From 0730a11b3661407129a05b545f27e1186b4a8e38 Mon Sep 17 00:00:00 2001
From: shruti2522 <shruti.apc01@gmail.com>
Date: Sat, 15 Aug 2026 03:17:26 +0000
Subject: [PATCH 01/19] feat(gc): integrate oscars GC backend into boa_engine

---
 .github/workflows/pull_request.yml            |   1 +
 .github/workflows/rust.yml                    |   2 +
 .github/workflows/test262.yml                 |   2 +
 .github/workflows/webassembly.yml             |   2 +
 Cargo.lock                                    |  11 +-
 Cargo.toml                                    |   4 +
 core/engine/Cargo.toml                        |   1 +
 core/engine/src/builtins/eval/mod.rs          |  14 +--
 .../src/builtins/finalization_registry/mod.rs |  28 ++---
 .../builtins/finalization_registry/tests.rs   |   1 +
 .../engine/src/builtins/function/arguments.rs |   4 +-
 core/engine/src/builtins/function/mod.rs      |  10 +-
 core/engine/src/builtins/generator/mod.rs     |   2 +-
 .../src/builtins/intl/list_format/mod.rs      |   2 +-
 core/engine/src/builtins/intl/locale/mod.rs   |  13 +-
 core/engine/src/builtins/intl/locale/utils.rs |   4 +-
 core/engine/src/builtins/json/mod.rs          |  11 +-
 core/engine/src/builtins/promise/mod.rs       |  27 +----
 core/engine/src/builtins/set/ordered_set.rs   |   6 +-
 core/engine/src/builtins/weak/weak_ref.rs     |   6 +-
 core/engine/src/builtins/weak_map/mod.rs      |  85 ++++++-------
 core/engine/src/builtins/weak_set/mod.rs      |   4 +-
 core/engine/src/bytecompiler/class.rs         |  12 +-
 core/engine/src/bytecompiler/function.rs      |   2 +-
 core/engine/src/context/mod.rs                |  14 +++
 core/engine/src/environments/runtime/mod.rs   |  14 ++-
 core/engine/src/error/mod.rs                  |   9 +-
 core/engine/src/host_defined.rs               |   2 +-
 core/engine/src/lib.rs                        |   4 +
 core/engine/src/module/loader/mod.rs          |   2 +-
 core/engine/src/module/mod.rs                 |  14 +--
 core/engine/src/module/source.rs              |  10 +-
 core/engine/src/module/synthetic.rs           |  12 +-
 .../src/native_function/continuation.rs       |   4 +-
 core/engine/src/native_function/mod.rs        |  21 ++--
 core/engine/src/object/builtins/jspromise.rs  |   5 +-
 .../src/object/builtins/jstypedarray.rs       |   2 +-
 core/engine/src/object/builtins/jsweakmap.rs  |   2 +-
 core/engine/src/object/builtins/jsweakset.rs  |   2 +-
 core/engine/src/object/jsobject.rs            |  24 ++--
 core/engine/src/object/mod.rs                 |  10 ++
 .../shape/shared_shape/forward_transition.rs  |  12 +-
 .../src/object/shape/shared_shape/mod.rs      |  19 +--
 core/engine/src/object/shape/unique_shape.rs  |  16 ++-
 core/engine/src/realm.rs                      |   4 +-
 core/engine/src/script.rs                     |   8 +-
 core/engine/src/value/equality.rs             |   2 +-
 core/engine/src/value/inner/legacy.rs         |   8 +-
 core/engine/src/value/inner/nan_boxed.rs      |  14 +--
 core/engine/src/value/integer.rs              |   8 +-
 core/engine/src/vm/code_block.rs              |   1 +
 core/engine/src/vm/inline_cache/mod.rs        |   1 +
 core/engine/src/vm/mod.rs                     |   2 +-
 core/engine/src/vm/opcode/await/mod.rs        |   7 +-
 core/engine/src/vm/opcode/function.rs         |   4 +-
 core/engine/src/vm/opcode/push/environment.rs |   6 +-
 core/engine/src/vm/tests.rs                   |   1 +
 core/gc/Cargo.toml                            |  13 +-
 core/gc/src/cell.rs                           |  10 +-
 core/gc/src/lib.rs                            | 114 +++++++++++++++++-
 core/gc/src/oscars_weak_map.rs                | 109 +++++++++++++++++
 core/gc/src/pointers/mutation_context.rs      |   6 +
 core/gc/src/pointers/weak_map.rs              |  13 ++
 core/gc/src/test/weak.rs                      |   2 +-
 core/gc/src/trace.rs                          |  12 +-
 core/interner/src/sym.rs                      |  14 +--
 core/macros/src/lib.rs                        |  38 +++---
 core/runtime/src/abort/mod.rs                 |   3 +-
 core/runtime/src/console/tests.rs             |  24 ++--
 core/runtime/src/microtask/tests.rs           |   2 +-
 core/runtime/src/test262.rs                   |   6 +-
 core/string/Cargo.toml                        |   4 +
 core/string/src/builder.rs                    |   8 +-
 core/string/src/lib.rs                        |  16 +++
 core/string/src/tests.rs                      |   4 +-
 examples/src/bin/derive.rs                    |   1 +
 examples/src/bin/jstypedarray.rs              |   2 +-
 tests/fuzz/Cargo.toml                         |   3 +
 tests/macros/tests/gcd_callback.rs            |   4 +-
 79 files changed, 631 insertions(+), 295 deletions(-)
 create mode 100644 core/gc/src/oscars_weak_map.rs

diff --git a/.github/workflows/pull_request.yml b/.github/workflows/pull_request.yml
index ae17ebe355e..fa208682396 100644
--- a/.github/workflows/pull_request.yml
+++ b/.github/workflows/pull_request.yml
@@ -5,6 +5,7 @@ on:
     branches:
       - main
       - releases/**
+      - dev/oscars-gc
 
 permissions:
   contents: read
diff --git a/.github/workflows/rust.yml b/.github/workflows/rust.yml
index 0fa015031fb..1dfd917b2a6 100644
--- a/.github/workflows/rust.yml
+++ b/.github/workflows/rust.yml
@@ -5,10 +5,12 @@ on:
     branches:
       - main
       - releases/**
+      - dev/oscars-gc
   push:
     branches:
       - main
       - releases/**
+      - dev/oscars-gc
   merge_group:
     types: [checks_requested]
   workflow_dispatch:
diff --git a/.github/workflows/test262.yml b/.github/workflows/test262.yml
index 6797efa033d..a8671fc37d0 100644
--- a/.github/workflows/test262.yml
+++ b/.github/workflows/test262.yml
@@ -5,6 +5,7 @@ on:
     branches:
       - main
       - releases/**
+      - dev/oscars-gc
 
 permissions:
   contents: read
@@ -15,6 +16,7 @@ concurrency:
 
 jobs:
   run_test262:
+    if: ${{ github.base_ref != 'dev/oscars-gc' }}
     name: Run the test262 test suite
     runs-on: ubuntu-latest
     timeout-minutes: 60
diff --git a/.github/workflows/webassembly.yml b/.github/workflows/webassembly.yml
index f9538775ebd..676a8602965 100644
--- a/.github/workflows/webassembly.yml
+++ b/.github/workflows/webassembly.yml
@@ -5,10 +5,12 @@ on:
     branches:
       - main
       - releases/**
+      - dev/oscars-gc
   push:
     branches:
       - main
       - releases/**
+      - dev/oscars-gc
   merge_group:
     types: [checks_requested]
 
diff --git a/Cargo.lock b/Cargo.lock
index 0585ab322c9..7e2cf9ee140 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -482,6 +482,7 @@ dependencies = [
  "icu_locale_core",
  "oscars",
  "thin-vec",
+ "typeid",
 ]
 
 [[package]]
@@ -593,6 +594,7 @@ version = "1.0.0-dev"
 dependencies = [
  "fast-float2",
  "itoa",
+ "oscars",
  "pastey",
  "rustc-hash 2.1.2",
  "ryu-js",
@@ -2846,17 +2848,22 @@ dependencies = [
 [[package]]
 name = "oscars"
 version = "0.1.0"
-source = "git+https://github.com/boa-dev/oscars.git?branch=main#592903ff2bec29ae3f4be7fecf4baded74674be2"
+source = "git+https://github.com/boa-dev/oscars.git?branch=main#ed5f692df0356338a82c113982449a3b5f7b1927"
 dependencies = [
+ "arrayvec",
+ "either",
  "hashbrown 0.16.1",
+ "icu_locale_core",
  "oscars_derive",
  "rustc-hash 2.1.2",
+ "thin-vec",
+ "typeid",
 ]
 
 [[package]]
 name = "oscars_derive"
 version = "0.1.0"
-source = "git+https://github.com/boa-dev/oscars.git?branch=main#592903ff2bec29ae3f4be7fecf4baded74674be2"
+source = "git+https://github.com/boa-dev/oscars.git?branch=main#ed5f692df0356338a82c113982449a3b5f7b1927"
 dependencies = [
  "cfg-if",
  "proc-macro2",
diff --git a/Cargo.toml b/Cargo.toml
index 41ce5060891..998e9f55e02 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -118,6 +118,7 @@ num-integer = "0.1.46"
 ryu-js = "1.0.2"
 tap = "1.0.1"
 thiserror = { version = "2.0.18", default-features = false }
+typeid = "1.0.3"
 dashmap = "6.2.1"
 num_enum = "0.7.6"
 itertools = { version = "0.15.0", default-features = false }
@@ -267,3 +268,6 @@ complexity = { level = "warn", priority = -1 }
 perf = { level = "warn", priority = -1 }
 pedantic = { level = "warn", priority = -1 }
 
+[patch."https://github.com/boa-dev/boa.git"]
+boa_string = { path = "core/string" }
+
diff --git a/core/engine/Cargo.toml b/core/engine/Cargo.toml
index d31abc302c8..eafe12de72b 100644
--- a/core/engine/Cargo.toml
+++ b/core/engine/Cargo.toml
@@ -26,6 +26,7 @@ embedded_lz4 = ["boa_macros/embedded_lz4", "lz4_flex"]
 jsvalue-enum = []
 deser = ["boa_interner/serde", "boa_ast/serde"]
 either = ["dep:either", "boa_gc/either"]
+oscars_backend = ["boa_gc/oscars_backend", "boa_string/oscars_backend"]
 
 # Enables the `Intl` builtin object and bundles a default ICU4X data provider.
 # Prefer this over `intl` if you just want to enable `Intl` without dealing with the
diff --git a/core/engine/src/builtins/eval/mod.rs b/core/engine/src/builtins/eval/mod.rs
index 7b0f9246640..0fd60137801 100644
--- a/core/engine/src/builtins/eval/mod.rs
+++ b/core/engine/src/builtins/eval/mod.rs
@@ -320,10 +320,8 @@ impl Eval {
 
         compiler.compile_statement_list(body.statements(), true, false);
 
-        let code_block = Gc::new(
-            &unsafe { boa_gc::MutationContext::dummy() },
-            compiler.finish(),
-        );
+        let finished = compiler.finish();
+        let code_block = Gc::new(&context.gc(), finished);
 
         // Strict calls don't need extensions, since all strict eval calls push a new
         // function environment before evaluating.
@@ -350,9 +348,11 @@ impl Eval {
         {
             let frame = context.vm.frame_mut();
             let global = frame.realm.environment();
-            frame
-                .environments
-                .push_lexical(lexical_scope.num_bindings_non_local(), global);
+            frame.environments.push_lexical(
+                lexical_scope.num_bindings_non_local(),
+                global,
+                unsafe { boa_gc::MutationContext::global() },
+            );
         }
 
         context
diff --git a/core/engine/src/builtins/finalization_registry/mod.rs b/core/engine/src/builtins/finalization_registry/mod.rs
index 4ec7ba0c0f3..810e40e287b 100644
--- a/core/engine/src/builtins/finalization_registry/mod.rs
+++ b/core/engine/src/builtins/finalization_registry/mod.rs
@@ -158,10 +158,7 @@ impl BuiltInConstructor for FinalizationRegistry {
             },
         );
 
-        let weak_registry = WeakGc::new(
-            &unsafe { boa_gc::MutationContext::dummy() },
-            registry.inner(),
-        );
+        let weak_registry = WeakGc::new(&context.gc(), registry.inner());
 
         {
             async fn inner_cleanup(
@@ -174,7 +171,7 @@ impl BuiltInConstructor for FinalizationRegistry {
                 };
 
                 let Some(registry) = weak_registry
-                    .upgrade(&unsafe { boa_gc::MutationContext::dummy() })
+                    .upgrade(&unsafe { boa_gc::MutationContext::global() })
                     .map(JsObject::from_inner)
                 else {
                     return Ok(JsValue::undefined());
@@ -205,7 +202,7 @@ impl FinalizationRegistry {
     /// [`FinalizationRegistry.prototype.register ( target, heldValue [ , unregisterToken ] )`][spec]
     ///
     /// [spec]: https://tc39.es/ecma262/sec-finalization-registry.prototype.register
-    fn register(this: &JsValue, args: &[JsValue], _context: &mut Context) -> JsResult<JsValue> {
+    fn register(this: &JsValue, args: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
         // 1. Let finalizationRegistry be the this value.
         // 2. Perform ? RequireInternalSlot(finalizationRegistry, [[Cells]]).
         let this = this.as_object();
@@ -257,10 +254,7 @@ impl FinalizationRegistry {
         //
         // TODO: support Symbols
         let unregister_token = match unregister_token.variant() {
-            JsVariant::Object(obj) => Some(WeakGc::new(
-                &unsafe { boa_gc::MutationContext::dummy() },
-                obj.inner(),
-            )),
+            JsVariant::Object(obj) => Some(WeakGc::new(&context.gc(), obj.inner())),
             // b. Set unregisterToken to empty.
             JsVariant::Undefined => None,
             // a. If unregisterToken is not undefined, throw a TypeError exception.
@@ -275,7 +269,7 @@ impl FinalizationRegistry {
         // 6. Let cell be the Record { [[WeakRefTarget]]: target, [[HeldValue]]: heldValue, [[UnregisterToken]]: unregisterToken }.
         let cell = RegistryCell {
             target: Ephemeron::new(
-                &unsafe { boa_gc::MutationContext::dummy() },
+                &context.gc(),
                 target_obj.inner(),
                 CleanupSignaler(Cell::new(Some(
                     registry.cleanup_notifier.clone().downgrade(),
@@ -295,7 +289,7 @@ impl FinalizationRegistry {
     /// [`FinalizationRegistry.prototype.unregister ( unregisterToken )`][spec]
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-finalization-registry.prototype.unregister
-    fn unregister(this: &JsValue, args: &[JsValue], _context: &mut Context) -> JsResult<JsValue> {
+    fn unregister(this: &JsValue, args: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
         // 1. Let finalizationRegistry be the this value.
         // 2. Perform ? RequireInternalSlot(finalizationRegistry, [[Cells]]).
         let this = this.as_object();
@@ -338,20 +332,16 @@ impl FinalizationRegistry {
 
             // a. If cell.[[UnregisterToken]] is not empty and SameValue(cell.[[UnregisterToken]], unregisterToken) is true, then
             if let Some(tok) = cell.unregister_token.as_ref()
-                && let Some(tok) = tok.upgrade(&unsafe { boa_gc::MutationContext::dummy() })
+                && let Some(tok) = tok.upgrade(&context.gc())
                 && Gc::ptr_eq(&tok, unregister_token)
             {
                 // i. Remove cell from finalizationRegistry.[[Cells]].
                 let cell = registry.cells.swap_remove(i);
-                let _key = cell
-                    .target
-                    .key(&unsafe { boa_gc::MutationContext::dummy() });
+                let _key = cell.target.key(&context.gc());
 
                 // TODO: it might be better to add a special ref for the value that
                 // also preserves the original key instead.
-                cell.target
-                    .value(&unsafe { boa_gc::MutationContext::dummy() })
-                    .and_then(|v| v.0.take());
+                cell.target.value(&context.gc()).and_then(|v| v.0.take());
 
                 // ii. Set removed to true.
                 removed = true;
diff --git a/core/engine/src/builtins/finalization_registry/tests.rs b/core/engine/src/builtins/finalization_registry/tests.rs
index 602bcc53586..0c4802e0093 100644
--- a/core/engine/src/builtins/finalization_registry/tests.rs
+++ b/core/engine/src/builtins/finalization_registry/tests.rs
@@ -1,3 +1,4 @@
+#[cfg(not(feature = "oscars_backend"))]
 mod miri {
 
     use indoc::indoc;
diff --git a/core/engine/src/builtins/function/arguments.rs b/core/engine/src/builtins/function/arguments.rs
index 81fe3f10043..ab339f96d07 100644
--- a/core/engine/src/builtins/function/arguments.rs
+++ b/core/engine/src/builtins/function/arguments.rs
@@ -1,3 +1,5 @@
+#![allow(clippy::trivially_copy_pass_by_ref)]
+#![allow(clippy::needless_pass_by_value)]
 use crate::{
     Context, JsData, JsExpect, JsResult, JsValue,
     bytecompiler::ToJsString,
@@ -124,7 +126,7 @@ impl MappedArguments {
             .get(index as usize)
             .copied()
             .flatten()?;
-        self.environment.get(binding_index)
+        (*self.environment).get(binding_index)
     }
 
     /// Set the value of the binding at the given index in the function environment.
diff --git a/core/engine/src/builtins/function/mod.rs b/core/engine/src/builtins/function/mod.rs
index d7585a76994..498cb555b8c 100644
--- a/core/engine/src/builtins/function/mod.rs
+++ b/core/engine/src/builtins/function/mod.rs
@@ -1073,7 +1073,9 @@ pub(crate) fn function_call(
     if has_binding_identifier {
         let frame = context.vm.frame_mut();
         let global = frame.realm.environment();
-        let index = frame.environments.push_lexical(1, global);
+        let index = frame
+            .environments
+            .push_lexical(1, global, unsafe { boa_gc::MutationContext::global() });
         frame.environments.put_lexical_value(
             BindingLocatorScope::Stack(index),
             0,
@@ -1091,6 +1093,7 @@ pub(crate) fn function_call(
             scope,
             FunctionSlots::new(this, function_object.clone(), None),
             global,
+            unsafe { boa_gc::MutationContext::global() },
         );
     }
 
@@ -1181,7 +1184,9 @@ fn function_construct(
     if has_binding_identifier {
         let frame = context.vm.frame_mut();
         let global = frame.realm.environment();
-        let index = frame.environments.push_lexical(1, global);
+        let index = frame
+            .environments
+            .push_lexical(1, global, unsafe { boa_gc::MutationContext::global() });
         frame.environments.put_lexical_value(
             BindingLocatorScope::Stack(index),
             0,
@@ -1210,6 +1215,7 @@ fn function_construct(
                 ),
             ),
             global,
+            unsafe { boa_gc::MutationContext::global() },
         );
     }
 
diff --git a/core/engine/src/builtins/generator/mod.rs b/core/engine/src/builtins/generator/mod.rs
index 85e086e9419..17e60e63aec 100644
--- a/core/engine/src/builtins/generator/mod.rs
+++ b/core/engine/src/builtins/generator/mod.rs
@@ -46,7 +46,7 @@ pub(crate) enum GeneratorState {
 // Need to manually implement, since `Trace` adds a `Drop` impl which disallows destructuring.
 unsafe impl Trace for GeneratorState {
     custom_trace!(this, mark, {
-        match &this {
+        match this {
             Self::SuspendedStart { context } | Self::SuspendedYield { context } => mark(context),
             Self::Executing | Self::Completed => {}
         }
diff --git a/core/engine/src/builtins/intl/list_format/mod.rs b/core/engine/src/builtins/intl/list_format/mod.rs
index 9c9bb2e0200..403fca045e6 100644
--- a/core/engine/src/builtins/intl/list_format/mod.rs
+++ b/core/engine/src/builtins/intl/list_format/mod.rs
@@ -329,7 +329,7 @@ impl ListFormat {
                 part: writeable::Part,
                 mut f: impl FnMut(&mut Self::SubPartsWrite) -> core::fmt::Result,
             ) -> core::fmt::Result {
-                assert!(part.category == "list");
+                assert_eq!(part.category, "list");
                 let mut string = WriteString(String::new());
                 f(&mut string)?;
                 if !string.0.is_empty() {
diff --git a/core/engine/src/builtins/intl/locale/mod.rs b/core/engine/src/builtins/intl/locale/mod.rs
index 2930d0adf7a..949f5b094ce 100644
--- a/core/engine/src/builtins/intl/locale/mod.rs
+++ b/core/engine/src/builtins/intl/locale/mod.rs
@@ -349,14 +349,17 @@ impl Locale {
         // 1. Let loc be the this value.
         // 2. Perform ? RequireInternalSlot(loc, [[InitializedLocale]]).
         let object = this.as_object();
+        // Under `oscars_backend`, `downcast_ref` returns `GcRef<'_, Locale>`.
+        // Deref through the guard before cloning to get an owned `icu_locale::Locale`.
+        // This is required because `GcRef<'_, Locale>` doesn't implement `NativeObject`.
         let mut loc = object
             .as_ref()
             .and_then(|o| o.downcast_ref::<icu_locale::Locale>())
             .ok_or_else(|| {
                 JsNativeError::typ()
                     .with_message("`Locale.maximize` can only be called on a `Locale` object")
-            })?
-            .clone();
+            })
+            .map(|r| (*r).clone())?;
 
         // 3. Let maximal be the result of the Add Likely Subtags algorithm applied to loc.[[Locale]]. If an error is signaled, set maximal to loc.[[Locale]].
         context
@@ -387,6 +390,8 @@ impl Locale {
         // 1. Let loc be the this value.
         // 2. Perform ? RequireInternalSlot(loc, [[InitializedLocale]]).
         let object = this.as_object();
+        // Under `oscars_backend`, `downcast_ref` returns `GcRef<'_, Locale>`.
+        // Deref through the guard before cloning to get an owned `icu_locale::Locale`.
         let mut loc = object
             .as_ref()
             .and_then(|o| o.downcast_ref::<icu_locale::Locale>())
@@ -394,8 +399,8 @@ impl Locale {
                 JsNativeError::typ().with_message(
                     "`Locale.prototype.minimize` can only be called on a `Locale` object",
                 )
-            })?
-            .clone();
+            })
+            .map(|r| (*r).clone())?;
 
         // 3. Let minimal be the result of the Remove Likely Subtags algorithm applied to loc.[[Locale]]. If an error is signaled, set minimal to loc.[[Locale]].
         context
diff --git a/core/engine/src/builtins/intl/locale/utils.rs b/core/engine/src/builtins/intl/locale/utils.rs
index 1193f6d53c3..7dcf9b29a31 100644
--- a/core/engine/src/builtins/intl/locale/utils.rs
+++ b/core/engine/src/builtins/intl/locale/utils.rs
@@ -54,7 +54,9 @@ pub(crate) fn locale_from_value(tag: &JsValue, context: &mut Context) -> JsResul
     if let Some(tag) = object.as_ref().and_then(|obj| obj.downcast_ref::<Locale>()) {
         // 1. Let tag be kValue.[[Locale]].
         // No need to canonicalize since all `Locale` objects should already be canonicalized.
-        return Ok(tag.clone());
+        // Under `oscars_backend`, `downcast_ref` returns `GcRef<'_, Locale>`.
+        // Deref through the guard before cloning to clone the `Locale` value, not the wrapper.
+        return Ok((*tag).clone());
     }
 
     // iv. Else,
diff --git a/core/engine/src/builtins/json/mod.rs b/core/engine/src/builtins/json/mod.rs
index be01ebb234b..3bc2f4f9abc 100644
--- a/core/engine/src/builtins/json/mod.rs
+++ b/core/engine/src/builtins/json/mod.rs
@@ -307,10 +307,8 @@ impl Json {
                 SourcePath::Json,
             );
             compiler.compile_statement_list(script.statements(), true, false);
-            Gc::new(
-                &unsafe { boa_gc::MutationContext::dummy() },
-                compiler.finish(),
-            )
+            let finished = compiler.finish();
+            Gc::new(&context.gc(), finished)
         };
 
         let realm = context.realm().clone();
@@ -815,7 +813,10 @@ impl Json {
             // d. Else if value has a [[BigIntData]] internal slot, then
             else if let Some(bigint) = obj.downcast_ref::<JsBigInt>() {
                 // i. Set value to value.[[BigIntData]].
-                value = bigint.clone().into();
+                // SAFETY: Under oscars_backend, `downcast_ref` returns a `GcRef<'_, JsBigInt>`.
+                // We must deref through the guard before calling `.clone()` so that we clone
+                // the inner `JsBigInt`, not the `GcRef` wrapper.
+                value = (*bigint).clone().into();
             }
             // e. Else if value has a [[IsRawJSON]] internal slot, then
             else if obj.is::<RawJson>() {
diff --git a/core/engine/src/builtins/promise/mod.rs b/core/engine/src/builtins/promise/mod.rs
index e79b52fc256..f03ef9500da 100644
--- a/core/engine/src/builtins/promise/mod.rs
+++ b/core/engine/src/builtins/promise/mod.rs
@@ -244,7 +244,7 @@ impl PromiseCapability {
         // 2. NOTE: C is assumed to be a constructor function that supports the parameter conventions of the Promise constructor (see 27.2.3.1).
         // 3. Let promiseCapability be the PromiseCapability Record { [[Promise]]: undefined, [[Resolve]]: undefined, [[Reject]]: undefined }.
         let promise_capability = Gc::new(
-            &unsafe { boa_gc::MutationContext::dummy() },
+            &context.gc(),
             GcRefCell::new(RejectResolve {
                 reject: JsValue::undefined(),
                 resolve: JsValue::undefined(),
@@ -656,10 +656,7 @@ impl Promise {
         }
 
         // 1. Let values be a new empty List.
-        let values = Gc::new(
-            &unsafe { boa_gc::MutationContext::dummy() },
-            GcRefCell::new(Vec::new()),
-        );
+        let values = Gc::new(&context.gc(), GcRefCell::new(Vec::new()));
 
         // 2. Let remainingElementsCount be the Record { [[Value]]: 1 }.
         let remaining_elements_count = Rc::new(Cell::new(1));
@@ -874,10 +871,7 @@ impl Promise {
         }
 
         // 1. Let values be a new empty List.
-        let values = Gc::new(
-            &unsafe { boa_gc::MutationContext::dummy() },
-            GcRefCell::new(Vec::new()),
-        );
+        let values = Gc::new(&context.gc(), GcRefCell::new(Vec::new()));
 
         // 2. Let remainingElementsCount be the Record { [[Value]]: 1 }.
         let remaining_elements_count = Rc::new(Cell::new(1));
@@ -1244,10 +1238,7 @@ impl Promise {
         let keys = Rc::new(RefCell::new(Vec::new()));
 
         // 3. Let values be a new empty List.
-        let values = Gc::new(
-            &unsafe { boa_gc::MutationContext::dummy() },
-            GcRefCell::new(Vec::new()),
-        );
+        let values = Gc::new(&context.gc(), GcRefCell::new(Vec::new()));
 
         // 4. Let remainingElementsCount be the Record { [[Value]]: 1 }.
         let remaining_elements_count = Rc::new(Cell::new(1));
@@ -1557,10 +1548,7 @@ impl Promise {
         }
 
         // 1. Let errors be a new empty List.
-        let errors = Gc::new(
-            &unsafe { boa_gc::MutationContext::dummy() },
-            GcRefCell::new(Vec::new()),
-        );
+        let errors = Gc::new(&context.gc(), GcRefCell::new(Vec::new()));
 
         // 2. Let remainingElementsCount be the Record { [[Value]]: 1 }.
         let remaining_elements_count = Rc::new(Cell::new(1));
@@ -2460,10 +2448,7 @@ impl Promise {
         // 1. Let alreadyResolved be the Record { [[Value]]: false }.
         // 5. Set resolve.[[Promise]] to promise.
         // 6. Set resolve.[[AlreadyResolved]] to alreadyResolved.
-        let promise = Gc::new(
-            &unsafe { boa_gc::MutationContext::dummy() },
-            Cell::new(Some(promise.clone())),
-        );
+        let promise = Gc::new(&context.gc(), Cell::new(Some(promise.clone())));
 
         // 2. Let stepsResolve be the algorithm steps defined in Promise Resolve Functions.
         // 3. Let lengthResolve be the number of non-optional parameters of the function definition in Promise Resolve Functions.
diff --git a/core/engine/src/builtins/set/ordered_set.rs b/core/engine/src/builtins/set/ordered_set.rs
index 6c604263662..a9888594441 100644
--- a/core/engine/src/builtins/set/ordered_set.rs
+++ b/core/engine/src/builtins/set/ordered_set.rs
@@ -15,9 +15,9 @@ pub struct OrderedSet {
 
 unsafe impl Trace for OrderedSet {
     custom_trace!(this, mark, {
-        for v in &this.inner {
-            if let MapKey::Key(v) = v {
-                mark(v);
+        for k in &this.inner {
+            if let MapKey::Key(key) = k {
+                mark(key);
             }
         }
     });
diff --git a/core/engine/src/builtins/weak/weak_ref.rs b/core/engine/src/builtins/weak/weak_ref.rs
index 77f136812ac..0804d3d5d92 100644
--- a/core/engine/src/builtins/weak/weak_ref.rs
+++ b/core/engine/src/builtins/weak/weak_ref.rs
@@ -87,7 +87,7 @@ impl BuiltInConstructor for WeakRef {
         let weak_ref = JsObject::from_proto_and_data_with_shared_shape(
             context.root_shape(),
             prototype,
-            WeakGc::new(&unsafe { boa_gc::MutationContext::dummy() }, target.inner()),
+            WeakGc::new(&context.gc(), target.inner()),
         );
 
         // 4. Perform AddToKeptObjects(target).
@@ -124,7 +124,7 @@ impl WeakRef {
         // https://tc39.es/ecma262/multipage/managing-memory.html#sec-weakrefderef
         // 1. Let target be weakRef.[[WeakRefTarget]].
         // 2. If target is not empty, then
-        if let Some(object) = weak_ref.upgrade(&unsafe { boa_gc::MutationContext::dummy() }) {
+        if let Some(object) = weak_ref.upgrade(&context.gc()) {
             let object = JsObject::from(object);
 
             // a. Perform AddToKeptObjects(target).
@@ -140,11 +140,13 @@ impl WeakRef {
 }
 
 #[cfg(test)]
+#[allow(unused_imports)]
 mod tests {
     use indoc::indoc;
 
     use crate::{JsNativeErrorKind, JsValue, TestAction, run_test_actions};
 
+    #[cfg(not(feature = "oscars_backend"))]
     #[test]
     fn weak_ref_collected() {
         run_test_actions([
diff --git a/core/engine/src/builtins/weak_map/mod.rs b/core/engine/src/builtins/weak_map/mod.rs
index adff36ecbfc..8f0bdf8de7c 100644
--- a/core/engine/src/builtins/weak_map/mod.rs
+++ b/core/engine/src/builtins/weak_map/mod.rs
@@ -28,7 +28,7 @@ pub(crate) type NativeWeakMap = boa_gc::WeakMap<ErasedVTableObject, JsValue>;
 #[derive(Debug, Trace, Finalize)]
 pub(crate) struct WeakMap;
 
-#[cfg(test)]
+#[cfg(all(test, not(feature = "oscars_backend")))]
 mod tests;
 
 impl IntrinsicObject for WeakMap {
@@ -97,7 +97,7 @@ impl BuiltInConstructor for WeakMap {
         let map = JsObject::from_proto_and_data_with_shared_shape(
             context.root_shape(),
             prototype,
-            NativeWeakMap::new(&unsafe { boa_gc::MutationContext::dummy() }),
+            NativeWeakMap::new(&context.gc()),
         )
         .upcast();
 
@@ -171,7 +171,7 @@ impl WeakMap {
     pub(crate) fn get(
         this: &JsValue,
         args: &[JsValue],
-        _context: &mut Context,
+        #[allow(unused_variables)] context: &mut Context,
     ) -> JsResult<JsValue> {
         // 1. Let M be the this value.
         // 2. Perform ? RequireInternalSlot(M, [[WeakMapData]]).
@@ -193,13 +193,8 @@ impl WeakMap {
         // 5. For each Record { [[Key]], [[Value]] } p of entries, do
         // a. If p.[[Key]] is not empty and SameValue(p.[[Key]], key) is true, return p.[[Value]].
         // 6. Return undefined.
-        if let Some(entry) = map.get(key.inner())
-            && let Some(val) = entry.value(&unsafe { boa_gc::MutationContext::dummy() })
-        {
-            Ok(val.clone())
-        } else {
-            Ok(JsValue::undefined())
-        }
+        let result: Option<JsValue> = map.get_value(key.inner());
+        Ok(result.unwrap_or_else(JsValue::undefined))
     }
 
     /// `WeakMap.prototype.has ( key )`
@@ -298,13 +293,14 @@ impl WeakMap {
     pub(crate) fn get_or_insert(
         this: &JsValue,
         args: &[JsValue],
-        _context: &mut Context,
+        #[allow(unused_variables)] context: &mut Context,
     ) -> JsResult<JsValue> {
         // 1. Let M be the this value.
         // 2. Perform ? RequireInternalSlot(M, [[WeakMapData]]).
         let object = this.as_object();
-        let map = object
-            .and_then(|obj| obj.clone().downcast::<NativeWeakMap>().ok())
+        let mut map = object
+            .as_ref()
+            .and_then(JsObject::downcast_mut::<NativeWeakMap>)
             .ok_or_else(|| {
                 js_error!(TypeError:
                     "WeakMap.prototype.getOrInsert: expected 'this' to be a WeakMap object",
@@ -324,18 +320,13 @@ impl WeakMap {
         };
 
         // 4. For each Record { [[Key]], [[Value]] } p of M.[[WeakMapData]]
-        if let Some(existing) = map.borrow().data().get(key.inner())
-            && let Some(value) = existing.value(&unsafe { boa_gc::MutationContext::dummy() })
-        {
-            // a. If p.[[Key]] is not empty and SameValue(p.[[Key]], key) is true, return p.[[Value]].
-            return Ok(value.clone());
+        if let Some(existing) = map.get_value(key.inner()) {
+            return Ok(existing);
         }
 
         // 5-6. Insert the new record with provided value and return it.
         let value = args.get_or_undefined(1).clone();
-        map.borrow_mut()
-            .data_mut()
-            .insert(key.inner(), value.clone());
+        map.insert(key.inner(), value.clone());
         Ok(value)
     }
 
@@ -353,23 +344,12 @@ impl WeakMap {
     pub(crate) fn get_or_insert_computed(
         this: &JsValue,
         args: &[JsValue],
-        context: &mut Context,
+        #[allow(unused_variables)] context: &mut Context,
     ) -> JsResult<JsValue> {
         // 1. Let M be the this value.
         // 2. Perform ? RequireInternalSlot(M, [[WeakMapData]]).
         let object = this.as_object();
-        let map = object
-            .and_then(|obj| obj.clone().downcast::<NativeWeakMap>().ok())
-            .ok_or_else(|| {
-                js_error!(TypeError:
-                    "WeakMap.prototype.getOrInsertComputed: expected 'this' to be a WeakMap object",
-                )
-            })?;
 
-        // 3. If CanBeHeldWeakly(key) is false, throw a TypeError exception.
-        // TODO: Implement proper CanBeHeldWeakly once available. For now, only
-        //       objects are accepted as keys; symbols should be allowed in the
-        //       future according to the proposal.
         let key_value = args.get_or_undefined(0).clone();
         let Some(key_obj) = key_value.as_object() else {
             return Err(js_error!(TypeError:
@@ -378,6 +358,19 @@ impl WeakMap {
             ));
         };
 
+        if let Some(map) = object
+            .as_ref()
+            .and_then(JsObject::downcast_ref::<NativeWeakMap>)
+        {
+            if let Some(existing) = map.get_value(key_obj.inner()) {
+                return Ok(existing);
+            }
+        } else {
+            return Err(js_error!(TypeError:
+                "WeakMap.prototype.getOrInsertComputed: expected 'this' to be a WeakMap object",
+            ));
+        }
+
         // 4. If IsCallable(callback) is false, throw a TypeError exception.
         let Some(callback_fn) = args.get_or_undefined(1).as_callable() else {
             return Err(js_error!(TypeError:
@@ -385,26 +378,20 @@ impl WeakMap {
             ));
         };
 
-        // 5. For each Record { [[Key]], [[Value]] } p of M.[[WeakMapData]]
-        if let Some(existing) = map.borrow().data().get(key_obj.inner())
-            && let Some(value) = existing.value(&unsafe { boa_gc::MutationContext::dummy() })
-        {
-            // a. If p.[[Key]] is not empty and SameValue(p.[[Key]], key) is true, return p.[[Value]].
-            return Ok(value.clone());
-        }
-
         // 6. Let value be ? Call(callback, undefined, « key »).
         // 7. NOTE: The WeakMap may have been modified during execution of callback.
-        let value = callback_fn.call(
-            &JsValue::undefined(),
-            std::slice::from_ref(&key_value),
-            context,
-        )?;
+        let value = callback_fn.call(&JsValue::undefined(), &[key_obj.clone().into()], context)?;
 
         // 8-10. Insert or update the entry and return value.
-        map.borrow_mut()
-            .data_mut()
-            .insert(key_obj.inner(), value.clone());
+        let mut map = object
+            .as_ref()
+            .and_then(JsObject::downcast_mut::<NativeWeakMap>)
+            .ok_or_else(|| {
+                js_error!(TypeError:
+                    "WeakMap.prototype.getOrInsertComputed: expected 'this' to be a WeakMap object",
+                )
+            })?;
+        map.insert(key_obj.inner(), value.clone());
         Ok(value)
     }
 }
diff --git a/core/engine/src/builtins/weak_set/mod.rs b/core/engine/src/builtins/weak_set/mod.rs
index 50647b16881..f55b58114b6 100644
--- a/core/engine/src/builtins/weak_set/mod.rs
+++ b/core/engine/src/builtins/weak_set/mod.rs
@@ -86,7 +86,7 @@ impl BuiltInConstructor for WeakSet {
         let weak_set = JsObject::from_proto_and_data_with_shared_shape(
             context.root_shape(),
             prototype,
-            NativeWeakSet::new(&unsafe { boa_gc::MutationContext::dummy() }),
+            NativeWeakSet::new(&context.gc()),
         )
         .upcast();
 
@@ -255,5 +255,5 @@ impl WeakSet {
     }
 }
 
-#[cfg(test)]
+#[cfg(all(test, not(feature = "oscars_backend")))]
 mod tests;
diff --git a/core/engine/src/bytecompiler/class.rs b/core/engine/src/bytecompiler/class.rs
index a876cc80403..d98020efdc9 100644
--- a/core/engine/src/bytecompiler/class.rs
+++ b/core/engine/src/bytecompiler/class.rs
@@ -157,7 +157,7 @@ impl ByteCompiler<'_> {
         );
 
         let code = Gc::new(
-            &unsafe { boa_gc::MutationContext::dummy() },
+            &unsafe { boa_gc::MutationContext::global() },
             compiler.finish(),
         );
         let index = self.push_function_to_constants(code);
@@ -444,7 +444,7 @@ impl ByteCompiler<'_> {
                     field_compiler.code_block_flags |= CodeBlockFlags::IN_CLASS_FIELD_INITIALIZER;
 
                     let code = Gc::new(
-                        &unsafe { boa_gc::MutationContext::dummy() },
+                        &unsafe { boa_gc::MutationContext::global() },
                         field_compiler.finish(),
                     );
                     let index = self.push_function_to_constants(code);
@@ -493,7 +493,7 @@ impl ByteCompiler<'_> {
                     field_compiler.code_block_flags |= CodeBlockFlags::IN_CLASS_FIELD_INITIALIZER;
 
                     let code = Gc::new(
-                        &unsafe { boa_gc::MutationContext::dummy() },
+                        &unsafe { boa_gc::MutationContext::global() },
                         field_compiler.finish(),
                     );
                     let index = self.push_function_to_constants(code);
@@ -551,7 +551,7 @@ impl ByteCompiler<'_> {
                     field_compiler.code_block_flags |= CodeBlockFlags::IN_CLASS_FIELD_INITIALIZER;
 
                     let code = field_compiler.finish();
-                    let code = Gc::new(&unsafe { boa_gc::MutationContext::dummy() }, code);
+                    let code = Gc::new(&unsafe { boa_gc::MutationContext::global() }, code);
 
                     static_elements.push(StaticElement::StaticField {
                         code,
@@ -595,7 +595,7 @@ impl ByteCompiler<'_> {
                     field_compiler.code_block_flags |= CodeBlockFlags::IN_CLASS_FIELD_INITIALIZER;
 
                     let code = field_compiler.finish();
-                    let code = Gc::new(&unsafe { boa_gc::MutationContext::dummy() }, code);
+                    let code = Gc::new(&unsafe { boa_gc::MutationContext::global() }, code);
 
                     static_elements.push(StaticElement::StaticField {
                         code,
@@ -639,7 +639,7 @@ impl ByteCompiler<'_> {
                     }
 
                     let code = Gc::new(
-                        &unsafe { boa_gc::MutationContext::dummy() },
+                        &unsafe { boa_gc::MutationContext::global() },
                         compiler.finish(),
                     );
                     static_elements.push(StaticElement::StaticBlock(code));
diff --git a/core/engine/src/bytecompiler/function.rs b/core/engine/src/bytecompiler/function.rs
index b862326fc7b..d1633a34cd6 100644
--- a/core/engine/src/bytecompiler/function.rs
+++ b/core/engine/src/bytecompiler/function.rs
@@ -227,6 +227,6 @@ impl FunctionCompiler {
 
         let code = compiler.finish();
 
-        Gc::new(&unsafe { boa_gc::MutationContext::dummy() }, code)
+        Gc::new(&unsafe { boa_gc::MutationContext::global() }, code)
     }
 }
diff --git a/core/engine/src/context/mod.rs b/core/engine/src/context/mod.rs
index 78453d26078..dfde062671c 100644
--- a/core/engine/src/context/mod.rs
+++ b/core/engine/src/context/mod.rs
@@ -463,6 +463,20 @@ impl Context {
         &self.vm.frame().realm
     }
 
+    /// Returns [`boa_gc::MutationContext`] to allocate on the Gc heap
+    /// (eg. for [`Gc::new`])
+    ///
+    /// # Safety
+    /// Uses `dummy()` as a temporary bridge during the oscars GC migration.
+    /// Todo: replace with a real branding token in future
+    #[inline]
+    #[must_use]
+    pub fn gc(&self) -> boa_gc::MutationContext<'static, 'static> {
+        // SAFETY: `MutationContext` is a ZST phantom type, this is sound
+        // under boa's single-threaded GC invariant until migration is complete
+        unsafe { boa_gc::MutationContext::global() }
+    }
+
     /// Set the value of trace on the context
     #[cfg(feature = "trace")]
     #[inline]
diff --git a/core/engine/src/environments/runtime/mod.rs b/core/engine/src/environments/runtime/mod.rs
index 8f7b2dd26c6..59724b87c38 100644
--- a/core/engine/src/environments/runtime/mod.rs
+++ b/core/engine/src/environments/runtime/mod.rs
@@ -1,3 +1,5 @@
+#![allow(clippy::trivially_copy_pass_by_ref)]
+#![allow(clippy::needless_pass_by_value)]
 use crate::{
     Context, JsResult, JsString, JsSymbol, JsValue,
     object::{JsObject, PrivateName},
@@ -214,13 +216,14 @@ impl EnvironmentStack {
         &mut self,
         bindings_count: u32,
         global: &Gc<'static, DeclarativeEnvironment>,
+        gc: boa_gc::MutationContext<'static, '_>,
     ) -> u32 {
         let (poisoned, with) = self.compute_poisoned_with(global);
 
         let index = self.depth;
 
         self.push_env(Environment::Declarative(Gc::new(
-            &unsafe { boa_gc::MutationContext::dummy() },
+            &gc,
             DeclarativeEnvironment::new(
                 DeclarativeEnvironmentKind::Lexical(LexicalEnvironment::new(bindings_count)),
                 poisoned,
@@ -237,13 +240,14 @@ impl EnvironmentStack {
         scope: Scope,
         function_slots: FunctionSlots,
         global: &Gc<'static, DeclarativeEnvironment>,
+        gc: boa_gc::MutationContext<'static, '_>,
     ) {
         let num_bindings = scope.num_bindings_non_local();
 
         let (poisoned, with) = self.compute_poisoned_with(global);
 
         self.push_env(Environment::Declarative(Gc::new(
-            &unsafe { boa_gc::MutationContext::dummy() },
+            &gc,
             DeclarativeEnvironment::new(
                 DeclarativeEnvironmentKind::Function(FunctionEnvironment::new(
                     num_bindings,
@@ -257,10 +261,10 @@ impl EnvironmentStack {
     }
 
     /// Push a module environment on the environments stack.
-    pub(crate) fn push_module(&mut self, scope: Scope) {
+    pub(crate) fn push_module(&mut self, scope: Scope, gc: boa_gc::MutationContext<'static, '_>) {
         let num_bindings = scope.num_bindings_non_local();
         self.push_env(Environment::Declarative(Gc::new(
-            &unsafe { boa_gc::MutationContext::dummy() },
+            &gc,
             DeclarativeEnvironment::new(
                 DeclarativeEnvironmentKind::Module(ModuleEnvironment::new(num_bindings, scope)),
                 false,
@@ -414,7 +418,7 @@ impl EnvironmentStack {
     /// Push an environment onto the chain.
     fn push_env(&mut self, env: Environment) {
         self.tip = Some(Gc::new(
-            &unsafe { boa_gc::MutationContext::dummy() },
+            &unsafe { boa_gc::MutationContext::global() },
             EnvironmentNode {
                 env,
                 parent: self.tip.take(),
diff --git a/core/engine/src/error/mod.rs b/core/engine/src/error/mod.rs
index 1fc5c934c51..2e8ec0e6949 100644
--- a/core/engine/src/error/mod.rs
+++ b/core/engine/src/error/mod.rs
@@ -562,10 +562,13 @@ impl JsError {
                 let obj = val
                     .as_object()
                     .ok_or_else(|| TryNativeError::NotAnErrorObject(val.clone()))?;
+                // Under `oscars_backend`, `downcast_ref` returns a `GcRef<'_, Error>`.
+                // We deref through the guard before `.clone()` so we clone the `Error` value,
+                // not the GcRef wrapper. The `*` operator goes through `Deref<Target = Error>`.
                 let error_data: Error = obj
                     .downcast_ref::<Error>()
-                    .ok_or_else(|| TryNativeError::NotAnErrorObject(val.clone()))?
-                    .clone();
+                    .ok_or_else(|| TryNativeError::NotAnErrorObject(val.clone()))
+                    .map(|r| (*r).clone())?;
 
                 let try_get_property = |key: JsString, name, context: &mut Context| {
                     obj.try_get(key, context)
@@ -1496,7 +1499,7 @@ unsafe impl Trace for JsNativeErrorKind {
     custom_trace!(
         this,
         mark,
-        match &this {
+        match this {
             Self::Aggregate(errors) => mark(errors),
             Self::Error
             | Self::Eval
diff --git a/core/engine/src/host_defined.rs b/core/engine/src/host_defined.rs
index 96ea02e1f46..8547bd59e85 100644
--- a/core/engine/src/host_defined.rs
+++ b/core/engine/src/host_defined.rs
@@ -34,7 +34,7 @@ unsafe impl<T: ?Sized + Trace> Trace for HostDefined<T> {
     });
 }
 
-impl<T: ?Sized + Finalize> Finalize for HostDefined<T> {}
+impl<T: ?Sized> Finalize for HostDefined<T> {}
 
 impl HostDefined<dyn Any> {
     /// Insert a type into the [`HostDefined`].
diff --git a/core/engine/src/lib.rs b/core/engine/src/lib.rs
index 37558607d06..62b4c21497f 100644
--- a/core/engine/src/lib.rs
+++ b/core/engine/src/lib.rs
@@ -71,6 +71,10 @@
 
     // Add temporarily - Needs addressing
     clippy::missing_panics_doc,
+
+    // Expected when feature "oscars_backend" is enabled, since Gc becomes a Copy type
+    clippy::clone_on_copy,
+    clippy::cloned_instead_of_copied,
 )]
 
 extern crate self as boa_engine;
diff --git a/core/engine/src/module/loader/mod.rs b/core/engine/src/module/loader/mod.rs
index 21b0ed06b2f..a9bf45844ff 100644
--- a/core/engine/src/module/loader/mod.rs
+++ b/core/engine/src/module/loader/mod.rs
@@ -287,7 +287,7 @@ impl ModuleLoader for MapModuleLoader {
     }
 }
 
-#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash, boa_gc::Trace, boa_gc::Finalize)]
 struct ModuleCacheKey {
     path: PathBuf,
     attributes: Box<[ImportAttribute]>,
diff --git a/core/engine/src/module/mod.rs b/core/engine/src/module/mod.rs
index e34f8a8329d..e8f260aae5b 100644
--- a/core/engine/src/module/mod.rs
+++ b/core/engine/src/module/mod.rs
@@ -287,7 +287,7 @@ impl Module {
 
         Ok(Self {
             inner: Gc::new(
-                &unsafe { boa_gc::MutationContext::dummy() },
+                &context.gc(),
                 ModuleRepr {
                     realm,
                     namespace: GcRefCell::default(),
@@ -319,7 +319,7 @@ impl Module {
 
         Self {
             inner: Gc::new(
-                &unsafe { boa_gc::MutationContext::dummy() },
+                &context.gc(),
                 ModuleRepr {
                     realm,
                     namespace: GcRefCell::default(),
@@ -826,10 +826,7 @@ fn into_js_module() {
     let bar_count = Rc::new(RefCell::new(0));
     let dad_count = Rc::new(RefCell::new(0));
 
-    context.insert_data(Gc::new(
-        &unsafe { boa_gc::MutationContext::dummy() },
-        GcRefCell::new(JsValue::undefined()),
-    ));
+    context.insert_data(Gc::new(&context.gc(), GcRefCell::new(JsValue::undefined())));
 
     let module = unsafe {
         vec![
@@ -912,7 +909,10 @@ fn into_js_module() {
         promise_result.state()
     );
 
-    let result = context.get_data::<ResultType>().unwrap().borrow().clone();
+    // Under `oscars_backend`, `borrow()` returns `GcRef<'_, JsValue>`.
+    // Deref through the guard before cloning to clone the inner `JsValue`. If we clone
+    // the guard instead, the `GcRef` (and immutable borrow) stays alive, causing error.
+    let result = (*context.get_data::<ResultType>().unwrap().borrow()).clone();
 
     assert_eq!(*foo_count.borrow(), 2);
     assert_eq!(*bar_count.borrow(), 15);
diff --git a/core/engine/src/module/source.rs b/core/engine/src/module/source.rs
index 80fe607c6d6..b84319f6893 100644
--- a/core/engine/src/module/source.rs
+++ b/core/engine/src/module/source.rs
@@ -1824,17 +1824,17 @@ impl SourceTextModule {
             compiler.compile_module_item_list(source.items());
 
             (
-                Gc::new(
-                    &unsafe { boa_gc::MutationContext::dummy() },
-                    compiler.finish(),
-                ),
+                {
+                    let finished = compiler.finish();
+                    Gc::new(&context.gc(), finished)
+                },
                 functions,
             )
         };
 
         // 8. Let moduleContext be a new ECMAScript code execution context.
         let mut envs = EnvironmentStack::new();
-        envs.push_module(source.scope().clone());
+        envs.push_module(source.scope().clone(), context.gc());
         drop(status);
 
         // 9. Set the Function of moduleContext to null.
diff --git a/core/engine/src/module/synthetic.rs b/core/engine/src/module/synthetic.rs
index 613561c9558..0d30f788fd6 100644
--- a/core/engine/src/module/synthetic.rs
+++ b/core/engine/src/module/synthetic.rs
@@ -120,7 +120,7 @@ impl SyntheticModuleInitializer {
         // Hopefully, this unsafe operation will be replaced by the `CoerceUnsized` API in the
         // future: https://github.com/rust-lang/rust/issues/18598
         let ptr = Gc::into_raw(Gc::new(
-            &unsafe { boa_gc::MutationContext::dummy() },
+            &unsafe { boa_gc::MutationContext::global() },
             Callback {
                 f: closure,
                 captures,
@@ -131,7 +131,7 @@ impl SyntheticModuleInitializer {
         // meaning this is safe.
         unsafe {
             Self {
-                inner: Gc::from_raw(ptr),
+                inner: <Gc<'static, dyn TraceableCallback>>::from_raw(ptr),
             }
         }
     }
@@ -338,13 +338,11 @@ impl SyntheticModule {
 
         module_scope.escape_all_bindings();
 
-        let cb = Gc::new(
-            &unsafe { boa_gc::MutationContext::dummy() },
-            compiler.finish(),
-        );
+        let finished = compiler.finish();
+        let cb = Gc::new(&context.gc(), finished);
 
         let mut envs = EnvironmentStack::new();
-        envs.push_module(module_scope);
+        envs.push_module(module_scope, context.gc());
 
         for locator in exports {
             //     b. Perform ! env.InitializeBinding(exportName, undefined).
diff --git a/core/engine/src/native_function/continuation.rs b/core/engine/src/native_function/continuation.rs
index c18fa9e0327..abce83e1e0f 100644
--- a/core/engine/src/native_function/continuation.rs
+++ b/core/engine/src/native_function/continuation.rs
@@ -108,7 +108,7 @@ impl NativeCoroutine {
         // Hopefully, this unsafe operation will be replaced by the `CoerceUnsized` API in the
         // future: https://github.com/rust-lang/rust/issues/18598
         let ptr = Gc::into_raw(Gc::new(
-            &unsafe { boa_gc::MutationContext::dummy() },
+            &unsafe { boa_gc::MutationContext::global() },
             Coroutine {
                 f: closure,
                 captures,
@@ -118,7 +118,7 @@ impl NativeCoroutine {
         // meaning this is safe.
         unsafe {
             Self {
-                inner: Gc::from_raw(ptr),
+                inner: <Gc<'static, dyn TraceableCoroutine>>::from_raw(ptr),
             }
         }
     }
diff --git a/core/engine/src/native_function/mod.rs b/core/engine/src/native_function/mod.rs
index 22d661a3b38..11dc49adce8 100644
--- a/core/engine/src/native_function/mod.rs
+++ b/core/engine/src/native_function/mod.rs
@@ -279,7 +279,7 @@ impl NativeFunction {
         // Hopefully, this unsafe operation will be replaced by the `CoerceUnsized` API in the
         // future: https://github.com/rust-lang/rust/issues/18598
         let ptr = Gc::into_raw(Gc::new(
-            &unsafe { boa_gc::MutationContext::dummy() },
+            &unsafe { boa_gc::MutationContext::global() },
             Closure {
                 f: closure,
                 captures,
@@ -289,7 +289,7 @@ impl NativeFunction {
         // meaning this is safe.
         unsafe {
             Self {
-                inner: Inner::Closure(Gc::from_raw(ptr)),
+                inner: Inner::Closure(<Gc<'static, dyn TraceableClosure>>::from_raw(ptr)),
             }
         }
     }
@@ -340,15 +340,18 @@ pub(crate) fn native_function_call(
     context.check_runtime_limits()?;
     let this_function_object = obj.clone();
 
+    // Under `oscars_backend`, `downcast_ref` returns a `GcRef<'_, NativeFunctionObject>`.
+    // We deref through the guard with `(*guard).clone()` so we clone the inner struct
+    // (which is `Copy` friendly via `Clone`), not the `GcRef` wrapper itself
     let NativeFunctionObject {
         f: function,
         name,
         constructor,
         realm,
-    } = obj
+    } = (*obj
         .downcast_ref::<NativeFunctionObject>()
-        .expect("the object should be a native function object")
-        .clone();
+        .expect("the object should be a native function object"))
+    .clone();
 
     let pc = context.vm.frame().pc;
     let native_source_info = context.native_source_info();
@@ -395,15 +398,17 @@ fn native_function_construct(
     context.check_runtime_limits()?;
     let this_function_object = obj.clone();
 
+    // Under `oscars_backend`, `downcast_ref` returns a `GcRef<'_, NativeFunctionObject>`.
+    // We deref through the guard with `(*guard).clone()` so we clone the inner struct.
     let NativeFunctionObject {
         f: function,
         name,
         constructor,
         realm,
-    } = obj
+    } = (*obj
         .downcast_ref::<NativeFunctionObject>()
-        .expect("the object should be a native function object")
-        .clone();
+        .expect("the object should be a native function object"))
+    .clone();
 
     let pc = context.vm.frame().pc;
     let native_source_info = context.native_source_info();
diff --git a/core/engine/src/object/builtins/jspromise.rs b/core/engine/src/object/builtins/jspromise.rs
index 85aa1b26b2b..67931d22bf9 100644
--- a/core/engine/src/object/builtins/jspromise.rs
+++ b/core/engine/src/object/builtins/jspromise.rs
@@ -1,3 +1,4 @@
+#![allow(clippy::redundant_locals)]
 //! A Rust API wrapper for Boa's promise Builtin ECMAScript Object
 
 use super::{JsArray, JsFunction};
@@ -1094,7 +1095,7 @@ impl JsPromise {
         }
 
         let state = Gc::new(
-            &unsafe { boa_gc::MutationContext::dummy() },
+            &context.gc(),
             GcRefCell::new(Inner {
                 result: None,
                 task: None,
@@ -1429,6 +1430,8 @@ impl TryIntoJs for JsPromise {
 /// between promises and futures a bit easier.
 ///
 /// The only way to construct an instance of `JsFuture` is by calling [`JsPromise::into_js_future`].
+#[derive(Clone)]
+#[allow(missing_copy_implementations)]
 pub struct JsFuture {
     inner: Gc<'static, GcRefCell<Inner>>,
 }
diff --git a/core/engine/src/object/builtins/jstypedarray.rs b/core/engine/src/object/builtins/jstypedarray.rs
index 77ec287f050..6828d0f6b98 100644
--- a/core/engine/src/object/builtins/jstypedarray.rs
+++ b/core/engine/src/object/builtins/jstypedarray.rs
@@ -678,7 +678,7 @@ impl JsTypedArray {
     /// # fn main() -> JsResult<()> {
     /// let context = &mut Context::default();
     /// let array = JsUint8Array::from_iter(vec![1, 2, 3, 4, 5], context)?;
-    /// let num_to_modify = Gc::new(GcRefCell::new(0u8));
+    /// let num_to_modify = Gc::new(&context.gc(), GcRefCell::new(0u8));
     ///
     /// let js_function = FunctionObjectBuilder::new(
     ///     context.realm(),
diff --git a/core/engine/src/object/builtins/jsweakmap.rs b/core/engine/src/object/builtins/jsweakmap.rs
index e752f696b95..d120be65a48 100644
--- a/core/engine/src/object/builtins/jsweakmap.rs
+++ b/core/engine/src/object/builtins/jsweakmap.rs
@@ -30,7 +30,7 @@ impl JsWeakMap {
             inner: JsObject::from_proto_and_data_with_shared_shape(
                 context.root_shape(),
                 context.intrinsics().constructors().weak_map().prototype(),
-                NativeWeakMap::new(&unsafe { boa_gc::MutationContext::dummy() }),
+                NativeWeakMap::new(&context.gc()),
             )
             .upcast(),
         }
diff --git a/core/engine/src/object/builtins/jsweakset.rs b/core/engine/src/object/builtins/jsweakset.rs
index 13d14095cc8..07a53fd4264 100644
--- a/core/engine/src/object/builtins/jsweakset.rs
+++ b/core/engine/src/object/builtins/jsweakset.rs
@@ -30,7 +30,7 @@ impl JsWeakSet {
             inner: JsObject::from_proto_and_data_with_shared_shape(
                 context.root_shape(),
                 context.intrinsics().constructors().weak_set().prototype(),
-                NativeWeakSet::new(&unsafe { boa_gc::MutationContext::dummy() }),
+                NativeWeakSet::new(&context.gc()),
             )
             .upcast(),
         }
diff --git a/core/engine/src/object/jsobject.rs b/core/engine/src/object/jsobject.rs
index cd30c5dceb4..711bb3cee2b 100644
--- a/core/engine/src/object/jsobject.rs
+++ b/core/engine/src/object/jsobject.rs
@@ -33,12 +33,6 @@ use std::{
 };
 use thin_vec::ThinVec;
 
-#[cfg(not(feature = "jsvalue-enum"))]
-use boa_gc::GcBox;
-
-#[cfg(not(feature = "jsvalue-enum"))]
-use std::ptr::NonNull;
-
 /// A wrapper type for an immutably borrowed type T.
 pub type Ref<'a, T> = GcRef<'a, T>;
 
@@ -86,8 +80,8 @@ pub(crate) struct VTableObject<T: NativeObject + ?Sized> {
 impl JsObject {
     /// Converts the `JsObject` into a raw pointer to its inner `GcBox<ErasedVTableObject>`.
     #[cfg(not(feature = "jsvalue-enum"))]
-    pub(crate) fn into_raw(self) -> NonNull<GcBox<ErasedVTableObject>> {
-        Gc::into_raw(self.inner)
+    pub(crate) fn into_raw(self) -> *const () {
+        Gc::into_raw(self.inner).as_ptr() as *const ()
     }
 
     /// Creates a new `JsObject` from a raw pointer.
@@ -96,9 +90,9 @@ impl JsObject {
     /// The caller must ensure that the pointer is valid and points to a `GcBox<ErasedVTableObject>`.
     /// The pointer must not be null.
     #[cfg(not(feature = "jsvalue-enum"))]
-    pub(crate) unsafe fn from_raw(raw: NonNull<GcBox<ErasedVTableObject>>) -> Self {
+    pub(crate) unsafe fn from_raw(raw: *const ()) -> Self {
         // SAFETY: The caller guaranteed the value to be a valid pointer to a `GcBox<ErasedVTableObject>`.
-        let inner = unsafe { Gc::from_raw(raw) };
+        let inner = unsafe { Gc::from_raw(core::ptr::NonNull::new_unchecked(raw as *mut _)) };
 
         JsObject { inner }
     }
@@ -128,7 +122,7 @@ impl JsObject {
         vtable: &'static InternalObjectMethods,
     ) -> Self {
         let inner = Gc::new(
-            &unsafe { boa_gc::MutationContext::dummy() },
+            &unsafe { boa_gc::MutationContext::global() },
             VTableObject {
                 object: GcRefCell::new(object),
                 vtable,
@@ -217,7 +211,7 @@ impl JsObject {
     ) -> Self {
         let internal_methods = data.internal_methods();
         let inner = Gc::new(
-            &unsafe { boa_gc::MutationContext::dummy() },
+            &unsafe { boa_gc::MutationContext::global() },
             VTableObject {
                 object: GcRefCell::new(Object {
                     data: ObjectData::new(data),
@@ -246,7 +240,7 @@ impl JsObject {
     ) -> JsObject<T> {
         let internal_methods = data.internal_methods();
         let inner = Gc::new(
-            &unsafe { boa_gc::MutationContext::dummy() },
+            &unsafe { boa_gc::MutationContext::global() },
             VTableObject {
                 object: GcRefCell::new(Object {
                     data: ObjectData::new(data),
@@ -1088,7 +1082,7 @@ impl<T: NativeObject> JsObject<T> {
     pub fn new<O: Into<Option<JsObject>>>(root_shape: &RootShape, prototype: O, data: T) -> Self {
         let internal_methods = data.internal_methods();
         let inner = Gc::new(
-            &unsafe { boa_gc::MutationContext::dummy() },
+            &unsafe { boa_gc::MutationContext::global() },
             VTableObject {
                 object: GcRefCell::new(Object {
                     data: ObjectData::new(data),
@@ -1126,7 +1120,7 @@ impl<T: NativeObject> JsObject<T> {
     pub fn new_unique<O: Into<Option<JsObject>>>(prototype: O, data: T) -> Self {
         let internal_methods = data.internal_methods();
         let inner = Gc::new(
-            &unsafe { boa_gc::MutationContext::dummy() },
+            &unsafe { boa_gc::MutationContext::global() },
             VTableObject {
                 object: GcRefCell::new(Object {
                     data: ObjectData::new(data),
diff --git a/core/engine/src/object/mod.rs b/core/engine/src/object/mod.rs
index 258da691647..edd29e6e913 100644
--- a/core/engine/src/object/mod.rs
+++ b/core/engine/src/object/mod.rs
@@ -96,6 +96,16 @@ impl<T: Any + Trace + JsData> NativeObject for T {
 // TODO: Use super trait casting in Rust 1.75
 impl dyn NativeObject {
     /// Returns `true` if the inner type is the same as `T`.
+    ///
+    /// # Type identity under `oscars_backend`
+    ///
+    /// 1. **`dyn NativeObject::is::<T>()`** (this method) uses [`std::any::TypeId::of::<T>()`].
+    ///    This is sound because `NativeObject: Any` requires `T: 'static`
+    /// 2. **[`JsObject::is::<T>()`]** uses `typeid::of::<VTableObject<T>>()`
+    ///    (via [`boa_gc::type_id_of`]), which supports non-`'static` branded lifetimes
+    ///
+    /// Do not replace the `std::any::TypeId` call below with `typeid::of`.
+    /// `std::any::TypeId` is authoritative for `Any` bounded types.
     #[inline]
     pub fn is<T: NativeObject>(&self) -> bool {
         // Get `TypeId` of the type this function is instantiated with.
diff --git a/core/engine/src/object/shape/shared_shape/forward_transition.rs b/core/engine/src/object/shape/shared_shape/forward_transition.rs
index 11934d51b79..88c286171d3 100644
--- a/core/engine/src/object/shape/shared_shape/forward_transition.rs
+++ b/core/engine/src/object/shape/shared_shape/forward_transition.rs
@@ -1,3 +1,5 @@
+#![allow(clippy::trivially_copy_pass_by_ref)]
+#![allow(clippy::needless_pass_by_value)]
 use std::fmt::Debug;
 
 use boa_gc::{Finalize, Gc, GcRefCell, Trace, WeakGc};
@@ -68,7 +70,7 @@ impl ForwardTransition {
 
         properties.map.insert(
             key,
-            WeakGc::new(&unsafe { boa_gc::MutationContext::dummy() }, value),
+            WeakGc::new(&unsafe { boa_gc::MutationContext::global() }, value),
         );
     }
 
@@ -83,11 +85,12 @@ impl ForwardTransition {
 
         prototypes.map.insert(
             key,
-            WeakGc::new(&unsafe { boa_gc::MutationContext::dummy() }, value),
+            WeakGc::new(&unsafe { boa_gc::MutationContext::global() }, value),
         );
     }
 
     /// Get a property transition, return [`None`] otherwise.
+    #[allow(clippy::cloned_instead_of_copied)]
     pub(super) fn get_property(&self, key: &TransitionKey) -> Option<WeakGc<SharedShapeInner>> {
         let this = self.inner.borrow();
         let transitions = this.properties.as_ref()?;
@@ -95,6 +98,7 @@ impl ForwardTransition {
     }
 
     /// Get a prototype transition, return [`None`] otherwise.
+    #[allow(clippy::cloned_instead_of_copied)]
     pub(super) fn get_prototype(&self, key: &JsPrototype) -> Option<WeakGc<SharedShapeInner>> {
         let this = self.inner.borrow();
         let transitions = this.prototypes.as_ref()?;
@@ -123,7 +127,7 @@ impl ForwardTransition {
         transitions.map.retain(|_, v| v.is_upgradable());
     }
 
-    #[cfg(test)]
+    #[cfg(all(test, not(feature = "oscars_backend")))]
     pub(crate) fn property_transitions_count(&self) -> (usize, u8) {
         let this = self.inner.borrow();
         this.properties.as_ref().map_or((0, 0), |transitions| {
@@ -134,7 +138,7 @@ impl ForwardTransition {
         })
     }
 
-    #[cfg(test)]
+    #[cfg(all(test, not(feature = "oscars_backend")))]
     pub(crate) fn prototype_transitions_count(&self) -> (usize, u8) {
         let this = self.inner.borrow();
         this.prototypes.as_ref().map_or((0, 0), |transitions| {
diff --git a/core/engine/src/object/shape/shared_shape/mod.rs b/core/engine/src/object/shape/shared_shape/mod.rs
index 0a1609fd55a..cbbfb1dbecb 100644
--- a/core/engine/src/object/shape/shared_shape/mod.rs
+++ b/core/engine/src/object/shape/shared_shape/mod.rs
@@ -1,7 +1,7 @@
 mod forward_transition;
 pub(crate) mod template;
 
-#[cfg(test)]
+#[cfg(all(test, not(feature = "oscars_backend")))]
 mod tests;
 
 use std::{collections::hash_map::RandomState, hash::Hash};
@@ -166,7 +166,7 @@ impl SharedShape {
     /// Create a new [`SharedShape`].
     fn new(inner: Inner) -> Self {
         Self {
-            inner: Gc::new(&unsafe { boa_gc::MutationContext::dummy() }, inner),
+            inner: Gc::new(&unsafe { boa_gc::MutationContext::global() }, inner),
         }
     }
 
@@ -188,7 +188,7 @@ impl SharedShape {
     /// Create a [`SharedShape`] change prototype transition.
     pub(crate) fn change_prototype_transition(&self, prototype: JsPrototype) -> Self {
         if let Some(shape) = self.forward_transitions().get_prototype(&prototype) {
-            if let Some(inner) = shape.upgrade(&unsafe { boa_gc::MutationContext::dummy() }) {
+            if let Some(inner) = shape.upgrade(&unsafe { boa_gc::MutationContext::global() }) {
                 return Self { inner };
             }
 
@@ -215,7 +215,7 @@ impl SharedShape {
     pub(crate) fn insert_property_transition(&self, key: TransitionKey) -> Self {
         // Check if we have already created such a transition, if so use it!
         if let Some(shape) = self.forward_transitions().get_property(&key) {
-            if let Some(inner) = shape.upgrade(&unsafe { boa_gc::MutationContext::dummy() }) {
+            if let Some(inner) = shape.upgrade(&unsafe { boa_gc::MutationContext::global() }) {
                 return Self { inner };
             }
 
@@ -253,7 +253,7 @@ impl SharedShape {
 
         // Check if we have already created such a transition, if so use it!
         if let Some(shape) = self.forward_transitions().get_property(&key) {
-            if let Some(inner) = shape.upgrade(&unsafe { boa_gc::MutationContext::dummy() }) {
+            if let Some(inner) = shape.upgrade(&unsafe { boa_gc::MutationContext::global() }) {
                 let action = if slot.attributes.width_match(key.attributes) {
                     ChangeTransitionAction::Nothing
                 } else if slot.attributes.is_accessor_descriptor() {
@@ -488,15 +488,20 @@ impl WeakSharedShape {
         Some(SharedShape {
             inner: self
                 .inner
-                .upgrade(&unsafe { boa_gc::MutationContext::dummy() })?,
+                .upgrade(&unsafe { boa_gc::MutationContext::global() })?,
         })
     }
+
+    #[allow(dead_code)]
+    pub(crate) fn is_upgradable(&self) -> bool {
+        self.inner.is_upgradable()
+    }
 }
 
 impl From<&SharedShape> for WeakSharedShape {
     fn from(value: &SharedShape) -> Self {
         WeakSharedShape {
-            inner: WeakGc::new(&unsafe { boa_gc::MutationContext::dummy() }, &value.inner),
+            inner: WeakGc::new(&unsafe { boa_gc::MutationContext::global() }, &value.inner),
         }
     }
 }
diff --git a/core/engine/src/object/shape/unique_shape.rs b/core/engine/src/object/shape/unique_shape.rs
index 6947489a526..b050e4bf5eb 100644
--- a/core/engine/src/object/shape/unique_shape.rs
+++ b/core/engine/src/object/shape/unique_shape.rs
@@ -38,7 +38,7 @@ impl UniqueShape {
     pub(crate) fn new(prototype: JsPrototype, property_table: PropertyTableInner) -> Self {
         Self {
             inner: Gc::new(
-                &unsafe { boa_gc::MutationContext::dummy() },
+                &unsafe { boa_gc::MutationContext::global() },
                 Inner {
                     property_table: RefCell::new(property_table),
                     prototype: GcRefCell::new(prototype),
@@ -58,7 +58,10 @@ impl UniqueShape {
 
     /// Get the prototype of the [`UniqueShape`].
     pub(crate) fn prototype(&self) -> JsPrototype {
-        self.inner.prototype.borrow().clone()
+        // Under `oscars_backend`, `GcRefCell::borrow()` returns `GcRef<'_, Option<JsObject>>`.
+        // Deref through the guard before cloning to get the inner `Option<JsObject>` value.
+        // This is what the `JsPrototype` return type requires.
+        (*self.inner.prototype.borrow()).clone()
     }
 
     /// Get the property table of the [`UniqueShape`].
@@ -258,15 +261,20 @@ impl WeakUniqueShape {
         Some(UniqueShape {
             inner: self
                 .inner
-                .upgrade(&unsafe { boa_gc::MutationContext::dummy() })?,
+                .upgrade(&unsafe { boa_gc::MutationContext::global() })?,
         })
     }
+
+    #[allow(dead_code)]
+    pub(crate) fn is_upgradable(&self) -> bool {
+        self.inner.is_upgradable()
+    }
 }
 
 impl From<&UniqueShape> for WeakUniqueShape {
     fn from(value: &UniqueShape) -> Self {
         WeakUniqueShape {
-            inner: WeakGc::new(&unsafe { boa_gc::MutationContext::dummy() }, &value.inner),
+            inner: WeakGc::new(&unsafe { boa_gc::MutationContext::global() }, &value.inner),
         }
     }
 }
diff --git a/core/engine/src/realm.rs b/core/engine/src/realm.rs
index 84bf5c39cf2..c133ce823eb 100644
--- a/core/engine/src/realm.rs
+++ b/core/engine/src/realm.rs
@@ -87,14 +87,14 @@ impl Realm {
             .create_global_this(&intrinsics)
             .unwrap_or_else(|| global_object.clone());
         let environment = Gc::new(
-            &unsafe { boa_gc::MutationContext::dummy() },
+            &unsafe { boa_gc::MutationContext::global() },
             DeclarativeEnvironment::global(),
         );
         let scope = Scope::new_global();
 
         let realm = Self {
             inner: Gc::new(
-                &unsafe { boa_gc::MutationContext::dummy() },
+                &unsafe { boa_gc::MutationContext::global() },
                 Inner {
                     intrinsics,
                     environment,
diff --git a/core/engine/src/script.rs b/core/engine/src/script.rs
index f11dbc61168..e7d5a36144e 100644
--- a/core/engine/src/script.rs
+++ b/core/engine/src/script.rs
@@ -105,7 +105,7 @@ impl Script {
 
         Ok(Self {
             inner: Gc::new(
-                &unsafe { boa_gc::MutationContext::dummy() },
+                &context.gc(),
                 Inner {
                     realm: realm.unwrap_or_else(|| context.realm().clone()),
                     phase: GcRefCell::new(ScriptPhase::Ast(code)),
@@ -162,10 +162,8 @@ impl Script {
             compiler.global_declaration_instantiation(source);
             compiler.compile_statement_list(source.statements(), true, false);
 
-            Gc::new(
-                &unsafe { boa_gc::MutationContext::dummy() },
-                compiler.finish(),
-            )
+            let finished = compiler.finish();
+            Gc::new(&context.gc(), finished)
         };
 
         *self.inner.phase.borrow_mut() = ScriptPhase::Codeblock(cb.clone());
diff --git a/core/engine/src/value/equality.rs b/core/engine/src/value/equality.rs
index 79a209253df..5ca76b9826c 100644
--- a/core/engine/src/value/equality.rs
+++ b/core/engine/src/value/equality.rs
@@ -238,7 +238,7 @@ impl JsValue {
     }
 
     fn same_value_non_numeric(x: &Self, y: &Self) -> bool {
-        debug_assert!(x.get_type() == y.get_type());
+        debug_assert_eq!(x.get_type(), y.get_type());
         match (x.variant(), y.variant()) {
             (JsVariant::Null, JsVariant::Null) | (JsVariant::Undefined, JsVariant::Undefined) => {
                 true
diff --git a/core/engine/src/value/inner/legacy.rs b/core/engine/src/value/inner/legacy.rs
index 087331990f3..5265b58f83f 100644
--- a/core/engine/src/value/inner/legacy.rs
+++ b/core/engine/src/value/inner/legacy.rs
@@ -33,8 +33,12 @@ impl Finalize for EnumBasedValue {
 #[allow(unsafe_op_in_unsafe_fn)]
 unsafe impl Trace for EnumBasedValue {
     custom_trace! {this, mark, {
-        if let Some(o) = this.as_object() {
-            mark(&o);
+        match this {
+            Self::Object(o) => mark(o),
+            Self::Symbol(s) => mark(s),
+            Self::String(s) => mark(s),
+            Self::BigInt(b) => mark(b),
+            _ => {}
         }
     }}
 }
diff --git a/core/engine/src/value/inner/nan_boxed.rs b/core/engine/src/value/inner/nan_boxed.rs
index 6a05d23fce4..d0c50bb3f6a 100644
--- a/core/engine/src/value/inner/nan_boxed.rs
+++ b/core/engine/src/value/inner/nan_boxed.rs
@@ -1,3 +1,4 @@
+#![allow(clippy::forget_non_drop)]
 //! A NaN-boxed inner value for JavaScript values.
 //!
 //! This [`JsValue`] is a float using `NaN` values to represent an inner
@@ -109,10 +110,9 @@
 #[cfg(feature = "annex-b")]
 use crate::builtins::is_html_dda::IsHTMLDDA;
 use crate::{
-    JsBigInt, JsObject, JsSymbol, JsVariant, bigint::RawBigInt, object::ErasedVTableObject,
-    symbol::RawJsSymbol, value::Type,
+    JsBigInt, JsObject, JsSymbol, JsVariant, bigint::RawBigInt, symbol::RawJsSymbol, value::Type,
 };
-use boa_gc::{Finalize, GcBox, Trace, custom_trace};
+use boa_gc::{Finalize, Trace, custom_trace};
 use boa_string::JsString;
 use core::fmt;
 use static_assertions::const_assert;
@@ -479,7 +479,7 @@ impl NanBoxedValue {
     #[must_use]
     #[inline(always)]
     pub(crate) fn object(value: JsObject) -> Self {
-        let ptr = value.into_raw();
+        let ptr = unsafe { NonNull::new_unchecked(value.into_raw().cast_mut()) };
         let addr = bits::tag_pointer(ptr, bits::MASK_OBJECT);
         Self::from_object_like(ptr, addr)
     }
@@ -684,11 +684,7 @@ impl NanBoxedValue {
     unsafe fn as_object_unchecked(&self) -> ManuallyDrop<JsObject> {
         let addr = bits::untag_pointer(self.value());
         // SAFETY: This is guaranteed by the caller.
-        unsafe {
-            ManuallyDrop::new(JsObject::from_raw(NonNull::new_unchecked(
-                self.ptr.with_addr(addr).cast::<GcBox<ErasedVTableObject>>(),
-            )))
-        }
+        unsafe { ManuallyDrop::new(JsObject::from_raw(self.ptr.with_addr(addr).cast::<()>())) }
     }
 
     /// Returns the value as a [`JsSymbol`].
diff --git a/core/engine/src/value/integer.rs b/core/engine/src/value/integer.rs
index 970ce0632f2..17fdbbdc23f 100644
--- a/core/engine/src/value/integer.rs
+++ b/core/engine/src/value/integer.rs
@@ -105,12 +105,12 @@ mod tests {
     fn test_eq() {
         let int: i64 = 42;
         let int_or_inf = IntegerOrInfinity::Integer(10);
-        assert!(int != int_or_inf);
-        assert!(int_or_inf != int);
+        assert_ne!(int, int_or_inf);
+        assert_ne!(int_or_inf, int);
 
         let int: i64 = 10;
-        assert!(int == int_or_inf);
-        assert!(int_or_inf == int);
+        assert_eq!(int, int_or_inf);
+        assert_eq!(int_or_inf, int);
     }
 
     #[test]
diff --git a/core/engine/src/vm/code_block.rs b/core/engine/src/vm/code_block.rs
index fb494a0a972..959256a90ce 100644
--- a/core/engine/src/vm/code_block.rs
+++ b/core/engine/src/vm/code_block.rs
@@ -330,6 +330,7 @@ impl CodeBlock {
     ///
     /// If the type of the [`Constant`] is not [`Constant::Function`].
     /// Or `index` is greater or equal to length of `constants`.
+    #[allow(clippy::clone_on_copy)]
     pub(crate) fn constant_function(&self, index: usize) -> Gc<'static, Self> {
         if let Some(Constant::Function(value)) = self.constants.get(index) {
             return value.clone();
diff --git a/core/engine/src/vm/inline_cache/mod.rs b/core/engine/src/vm/inline_cache/mod.rs
index c55aae8f767..2ae3b6d7d77 100644
--- a/core/engine/src/vm/inline_cache/mod.rs
+++ b/core/engine/src/vm/inline_cache/mod.rs
@@ -98,6 +98,7 @@ impl InlineCache {
 
         while i < entries.len() {
             if let Some(upgraded) = entries[i].shape.upgrade() {
+                let upgraded: Shape = upgraded;
                 if upgraded.to_addr_usize() == shape_addr {
                     result = Some((upgraded, entries[i].slot));
                     break;
diff --git a/core/engine/src/vm/mod.rs b/core/engine/src/vm/mod.rs
index b7da166b5c9..48d957adfaf 100644
--- a/core/engine/src/vm/mod.rs
+++ b/core/engine/src/vm/mod.rs
@@ -408,7 +408,7 @@ impl Vm {
         let mut frames = Vec::with_capacity(16);
         frames.push(CallFrame::new(
             Gc::new(
-                &unsafe { boa_gc::MutationContext::dummy() },
+                &unsafe { boa_gc::MutationContext::global() },
                 CodeBlock::new(JsString::default(), 0, true),
             ),
             None,
diff --git a/core/engine/src/vm/opcode/await/mod.rs b/core/engine/src/vm/opcode/await/mod.rs
index ad2c5fcbd54..f95a89e91cb 100644
--- a/core/engine/src/vm/opcode/await/mod.rs
+++ b/core/engine/src/vm/opcode/await/mod.rs
@@ -56,10 +56,7 @@ impl Await {
 
         let r#gen = GeneratorContext::from_current(context, None);
 
-        let captures = Gc::new(
-            &unsafe { boa_gc::MutationContext::dummy() },
-            Cell::new(Some(r#gen)),
-        );
+        let captures = Gc::new(&context.gc(), Cell::new(Some(r#gen)));
 
         // 3. Let fulfilledClosure be a new Abstract Closure with parameters (value) that captures asyncContext and performs the following steps when called:
         // 4. Let onFulfilled be CreateBuiltinFunction(fulfilledClosure, 1, "", « »).
@@ -132,7 +129,7 @@ impl Await {
 
                     Ok(JsValue::undefined())
                 },
-                captures,
+                captures.clone(),
             ),
         )
         .name(js_string!())
diff --git a/core/engine/src/vm/opcode/function.rs b/core/engine/src/vm/opcode/function.rs
index aa1e70fb325..8b125a308e6 100644
--- a/core/engine/src/vm/opcode/function.rs
+++ b/core/engine/src/vm/opcode/function.rs
@@ -61,7 +61,9 @@ impl GetHomeObject {
             .downcast_ref::<OrdinaryFunction>()
             .js_expect("must be function object")?
             .get_home_object()
-            .map_or_else(JsValue::null, |o| o.clone().into());
+            .map_or_else(JsValue::null, |o: &crate::object::JsObject| {
+                o.clone().into()
+            });
 
         context.vm.set_register(function.into(), home_object);
         Ok(())
diff --git a/core/engine/src/vm/opcode/push/environment.rs b/core/engine/src/vm/opcode/push/environment.rs
index 8f49f65b2c6..b27673d6d73 100644
--- a/core/engine/src/vm/opcode/push/environment.rs
+++ b/core/engine/src/vm/opcode/push/environment.rs
@@ -22,7 +22,9 @@ impl PushScope {
         let global = frame.realm.environment();
         frame
             .environments
-            .push_lexical(scope.num_bindings_non_local(), global);
+            .push_lexical(scope.num_bindings_non_local(), global, unsafe {
+                boa_gc::MutationContext::global()
+            });
     }
 }
 
@@ -82,7 +84,7 @@ impl PushPrivateEnvironment {
 
         let ptr: *const _ = class.as_ref();
         let environment = Gc::new(
-            &unsafe { boa_gc::MutationContext::dummy() },
+            &context.gc(),
             PrivateEnvironment::new(ptr.cast::<()>() as usize, names),
         );
 
diff --git a/core/engine/src/vm/tests.rs b/core/engine/src/vm/tests.rs
index 0b25366ac41..4655d97a09f 100644
--- a/core/engine/src/vm/tests.rs
+++ b/core/engine/src/vm/tests.rs
@@ -480,6 +480,7 @@ fn cross_context_function_call() {
 }
 
 // See: https://github.com/boa-dev/boa/issues/1848
+#[cfg(not(feature = "oscars_backend"))]
 #[test]
 fn long_object_chain_gc_trace_stack_overflow() {
     run_test_actions([
diff --git a/core/gc/Cargo.toml b/core/gc/Cargo.toml
index cf875a570ee..7b9b44be17e 100644
--- a/core/gc/Cargo.toml
+++ b/core/gc/Cargo.toml
@@ -12,18 +12,18 @@ rust-version.workspace = true
 
 [features]
 # Enable default implementations of trace and finalize for the thin-vec crate
-thin-vec = ["dep:thin-vec"]
+thin-vec = ["dep:thin-vec", "oscars?/thin-vec"]
 # Enable default implementations of trace and finalize for some `ICU4X` types
-icu = ["dep:icu_locale_core"]
+icu = ["dep:icu_locale_core", "oscars?/icu"]
 # Enable default implementations of trace and finalize for the `boa_string` crate
 boa_string = ["dep:boa_string"]
 # Enable default implementations of trace and finalize for the `either` crate
-either = ["dep:either"]
+either = ["dep:either", "oscars?/either"]
 # Enable default implementations of trace and finalize for the arrayvec crate
-arrayvec = ["dep:arrayvec"]
-default = ["boa_gc_backend"]
+arrayvec = ["dep:arrayvec", "oscars?/arrayvec"]
+default = []
 boa_gc_backend = []
-oscars_backend = ["dep:oscars"]
+oscars_backend = ["dep:oscars", "dep:typeid", "oscars?/std", "boa_string?/oscars_backend"]
 
 [dependencies]
 boa_macros.workspace = true
@@ -35,6 +35,7 @@ thin-vec = { workspace = true, optional = true }
 icu_locale_core = { workspace = true, optional = true }
 arrayvec = { workspace = true, optional = true }
 oscars = { git = "https://github.com/boa-dev/oscars.git", branch = "main", features = ["null_collector_branded"], optional = true }
+typeid = { workspace = true, optional = true }
 
 [lints]
 workspace = true
diff --git a/core/gc/src/cell.rs b/core/gc/src/cell.rs
index 674cf86ddb8..a07ce4ce731 100644
--- a/core/gc/src/cell.rs
+++ b/core/gc/src/cell.rs
@@ -59,13 +59,13 @@ impl BorrowFlag {
     ///  - This method will panic after incrementing if the borrow count overflows.
     #[inline]
     fn add_reading(self) -> Self {
-        assert!(self.borrowed() != BorrowState::Writing);
+        assert_ne!(self.borrowed(), BorrowState::Writing);
         let flags = Self(self.0 + 1);
 
         // This will fail if the borrow count overflows, which shouldn't happen,
         // but let's be safe
         {
-            assert!(flags.borrowed() == BorrowState::Reading);
+            assert_eq!(flags.borrowed(), BorrowState::Reading);
         }
         flags
     }
@@ -75,7 +75,7 @@ impl BorrowFlag {
     /// # Panic
     ///  - This method will panic if the current `BorrowState` is not reading.
     fn sub_reading(self) -> Self {
-        assert!(self.borrowed() == BorrowState::Reading);
+        assert_eq!(self.borrowed(), BorrowState::Reading);
         Self(self.0 - 1)
     }
 }
@@ -261,7 +261,7 @@ struct BorrowGcRef<'a> {
 
 impl Drop for BorrowGcRef<'_> {
     fn drop(&mut self) {
-        debug_assert!(self.borrow.get().borrowed() == BorrowState::Reading);
+        debug_assert_eq!(self.borrow.get().borrowed(), BorrowState::Reading);
         self.borrow.set(self.borrow.get().sub_reading());
     }
 }
@@ -411,7 +411,7 @@ struct BorrowGcRefMut<'a> {
 
 impl Drop for BorrowGcRefMut<'_> {
     fn drop(&mut self) {
-        debug_assert!(self.borrow.get().borrowed() == BorrowState::Writing);
+        debug_assert_eq!(self.borrow.get().borrowed(), BorrowState::Writing);
         self.borrow.set(BorrowFlag(UNUSED));
     }
 }
diff --git a/core/gc/src/lib.rs b/core/gc/src/lib.rs
index dec09a9c077..28b85aee782 100644
--- a/core/gc/src/lib.rs
+++ b/core/gc/src/lib.rs
@@ -14,6 +14,11 @@
     clippy::redundant_pub_crate,
     clippy::let_unit_value
 )]
+#![allow(missing_docs)]
+#![cfg_attr(
+    feature = "oscars_backend",
+    allow(unused_crate_dependencies, unused_extern_crates)
+)]
 
 extern crate self as boa_gc;
 
@@ -49,10 +54,111 @@ pub use internals::GcBox;
 pub use pointers::{Ephemeron, Gc, GcErased, MutationContext, WeakGc, WeakMap};
 
 #[cfg(feature = "oscars_backend")]
-pub use oscars::null_collector_branded::{
-    Ephemeron, Finalize, Gc, GcRefCell, MutationContext, Root, Trace, Tracer, WeakGc,
+pub use oscars::collectors::null_collector_branded::{
+    Finalize, Gc, GcBox, GcRefCell, Root, Trace, Tracer,
 };
 
+#[cfg(feature = "oscars_backend")]
+/// Re-export [`typeid::of`].
+///
+/// Computes a [`std::any::TypeId`] compatible value for `T` without requiring `T: 'static`.
+/// oscars collectors use this to stamp `GcBox` at allocation, ensuring consistent
+/// type comparisons.
+///
+/// Use this instead of `std::any::TypeId::of::<T>()` for types with non-`'static`
+/// branded lifetimes (like `'gc` or `'id`).
+pub use typeid::of as type_id_of;
+
+#[cfg(feature = "oscars_backend")]
+/// Type alias for Ephemeron
+pub type Ephemeron<K, V> = oscars::collectors::null_collector_branded::Ephemeron<'static, K, V>;
+
+#[cfg(feature = "oscars_backend")]
+/// A token granting permission to allocate into the GC arena.
+/// Lifetimes are `'static` for the null collector but should be forwarded for `mark_sweep_branded`.
+pub type MutationContext<'a, 'b> =
+    oscars::collectors::null_collector_branded::MutationContext<'static, 'static>;
+
+#[cfg(feature = "oscars_backend")]
+/// Type alias for `WeakGc`
+pub type WeakGc<T> = oscars::collectors::null_collector_branded::WeakGc<'static, T>;
+
+#[cfg(feature = "oscars_backend")]
+pub use oscars::collectors::null_collector_branded::cell::{GcRef, GcRefMut};
+
+#[cfg(feature = "oscars_backend")]
+mod oscars_weak_map;
+
+#[cfg(feature = "oscars_backend")]
+pub use oscars_weak_map::WeakMap;
+
+#[cfg(feature = "oscars_backend")]
+#[must_use]
+/// Returns whether finalizer is safe
+pub fn finalizer_safe() -> bool {
+    true
+}
+
+#[cfg(feature = "oscars_backend")]
+/// Implements an empty `Trace` trait for the specified types
+#[macro_export]
+macro_rules! empty_trace {
+    () => {
+        #[inline]
+        unsafe fn trace(&self, _tracer: &mut $crate::Tracer<'_>) {}
+        #[inline]
+        unsafe fn trace_non_roots(&self) {}
+        #[inline]
+        fn run_finalizer(&self) {
+            $crate::Finalize::finalize(self);
+        }
+    };
+    ($($T:ty),* $(,)?) => {
+        $(
+            unsafe impl $crate::Trace for $T {
+                $crate::empty_trace!();
+            }
+        )*
+    };
+}
+
+#[cfg(feature = "oscars_backend")]
+/// Macro for custom trace
+#[macro_export]
+macro_rules! custom_trace {
+    ($this:ident, $mark:ident, $body:expr) => {
+        #[inline]
+        unsafe fn trace(&self, tracer: &mut $crate::Tracer<'_>) {
+            let mut $mark = |it: &dyn $crate::Trace| {
+                // SAFETY: implementor must ensure trace is correctly implemented
+                unsafe {
+                    $crate::Trace::trace(it, tracer);
+                }
+            };
+            let $this = self;
+            // SAFETY: The implementor must ensure the trace body is safe
+            unsafe { $body }
+        }
+        #[inline]
+        unsafe fn trace_non_roots(&self) {
+            #[allow(non_snake_case)]
+            fn $mark<T: $crate::Trace + ?Sized>(_it: &T) {
+                // SAFETY: implementor must ensure trace is correctly implemented
+                unsafe {
+                    $crate::Trace::trace_non_roots(_it);
+                }
+            }
+            let $this = self;
+            // SAFETY: The implementor must ensure the trace body is safe
+            unsafe { $body }
+        }
+        #[inline]
+        fn run_finalizer(&self) {
+            $crate::Finalize::finalize(self);
+        }
+    };
+}
+
 #[cfg(not(feature = "oscars_backend"))]
 pub(crate) mod boa_allocator;
 
@@ -61,3 +167,7 @@ pub use boa_allocator::*;
 
 #[cfg(all(test, not(feature = "oscars_backend")))]
 mod test;
+
+#[cfg(feature = "oscars_backend")]
+/// Forces a garbage collection
+pub fn force_collect() {}
diff --git a/core/gc/src/oscars_weak_map.rs b/core/gc/src/oscars_weak_map.rs
new file mode 100644
index 00000000000..94bbe66e1a8
--- /dev/null
+++ b/core/gc/src/oscars_weak_map.rs
@@ -0,0 +1,109 @@
+//! Dummy `WeakMap` implementation for the `oscars_backend` feature.
+//!
+//! We define this here instead of in `oscars` because `boa_engine` needs to be able to modify the `WeakMap` even when it is shared, which it handles by using `GcRefCell`.
+//! Additionally, the `null_collector_branded` backend never frees memory, making a true weak map impossible.
+//! Defining a dummy wrapper in `boa_gc` fulfills engine requirements without polluting it with conditional compilation gates.
+//! All operations are leaky strong map operations to maintain API compatibility.
+
+use crate::{Finalize, Gc, MutationContext, Trace, Tracer};
+use std::collections::HashMap;
+use std::fmt::{Debug, Formatter, Result};
+
+#[derive(Clone)]
+pub struct WeakMap<K: Trace + ?Sized, V: Trace> {
+    map: HashMap<usize, V>,
+    _marker: std::marker::PhantomData<(*const K, *const V)>,
+}
+
+impl<K: Trace + ?Sized, V: Trace> Default for WeakMap<K, V> {
+    fn default() -> Self {
+        Self {
+            map: HashMap::new(),
+            _marker: std::marker::PhantomData,
+        }
+    }
+}
+
+impl<K: Trace + ?Sized, V: Trace> WeakMap<K, V> {
+    /// Creates a new, empty `WeakMap`.
+    ///
+    /// The `_mc` argument mirrors the non-oscars API; it is unused here.
+    #[must_use]
+    #[inline]
+    pub fn new(_mc: &MutationContext<'_, '_>) -> Self {
+        Self {
+            map: HashMap::new(),
+            _marker: std::marker::PhantomData,
+        }
+    }
+
+    /// Inserts a key value pair into the map
+    #[inline]
+    pub fn insert(&mut self, key: &Gc<'_, K>, value: V) {
+        self.map
+            .insert(std::ptr::from_ref(&**key).cast::<()>() as usize, value);
+    }
+
+    /// Removes a key from the map, returning `true` if the key was present.
+    /// Acts as a leaky strong map, so memory is never actually freed.
+    #[inline]
+    pub fn remove(&mut self, key: &Gc<'_, K>) -> bool {
+        self.map
+            .remove(&(std::ptr::from_ref(&**key).cast::<()>() as usize))
+            .is_some()
+    }
+
+    /// Returns `true` if the map contains the key.
+    #[must_use]
+    #[inline]
+    pub fn contains_key(&self, key: &Gc<'_, K>) -> bool {
+        self.map
+            .contains_key(&(std::ptr::from_ref(&**key).cast::<()>() as usize))
+    }
+
+    /// Returns the value associated with `key`, or `None`
+    #[must_use]
+    #[inline]
+    pub fn get(&self, key: &Gc<'_, K>) -> Option<V>
+    where
+        V: Clone,
+    {
+        self.map
+            .get(&(std::ptr::from_ref(&**key).cast::<()>() as usize))
+            .cloned()
+    }
+
+    /// Alias for `get` to match the `boa_gc` backend's `WeakMap` API.
+    #[must_use]
+    #[inline]
+    pub fn get_value(&self, key: &Gc<'_, K>) -> Option<V>
+    where
+        V: Clone,
+    {
+        self.get(key)
+    }
+}
+
+impl<K: Trace + ?Sized, V: Trace> Debug for WeakMap<K, V> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> Result {
+        f.debug_struct("WeakMap").finish()
+    }
+}
+
+impl<K: Trace + ?Sized, V: Trace> Finalize for WeakMap<K, V> {}
+
+unsafe impl<K: Trace + ?Sized, V: Trace> Trace for WeakMap<K, V> {
+    unsafe fn trace(&self, tracer: &mut Tracer<'_>) {
+        for value in self.map.values() {
+            unsafe { value.trace(tracer) };
+        }
+    }
+    unsafe fn trace_non_roots(&self) {
+        for value in self.map.values() {
+            unsafe { value.trace_non_roots() };
+        }
+    }
+    fn run_finalizer(&self) {
+        Finalize::finalize(self);
+    }
+}
diff --git a/core/gc/src/pointers/mutation_context.rs b/core/gc/src/pointers/mutation_context.rs
index fc527c6fc36..df771c72c23 100644
--- a/core/gc/src/pointers/mutation_context.rs
+++ b/core/gc/src/pointers/mutation_context.rs
@@ -17,4 +17,10 @@ impl MutationContext<'_, '_> {
             _marker: PhantomData,
         }
     }
+
+    /// Creates a global context (polyfill for the oscars backend).
+    #[must_use]
+    pub unsafe fn global() -> Self {
+        unsafe { Self::dummy() }
+    }
 }
diff --git a/core/gc/src/pointers/weak_map.rs b/core/gc/src/pointers/weak_map.rs
index f638e7d1648..624b1e71130 100644
--- a/core/gc/src/pointers/weak_map.rs
+++ b/core/gc/src/pointers/weak_map.rs
@@ -55,6 +55,19 @@ impl<K: Trace + ?Sized + 'static, V: Trace + 'static> WeakMap<K, V> {
     pub fn get<'a>(&'a self, key: &Gc<'_, K>) -> Option<GcRef<'a, Ephemeron<K, V>>> {
         GcRef::try_map(self.inner.borrow(), |inner| inner.get(key))
     }
+
+    /// Returns a cloned value from the ephemeron if it exists and has not been collected.
+    #[must_use]
+    #[inline]
+    pub fn get_value(&self, key: &Gc<'_, K>) -> Option<V>
+    where
+        V: Clone,
+    {
+        let ephemeron = self.get(key)?;
+        ephemeron
+            .value(&unsafe { crate::MutationContext::dummy() })
+            .map(|v| v.clone())
+    }
 }
 
 /// A hash map where the bucket type is an <code>[Ephemeron]\<K, V\></code>.
diff --git a/core/gc/src/test/weak.rs b/core/gc/src/test/weak.rs
index 9c4a108243a..20d3933f866 100644
--- a/core/gc/src/test/weak.rs
+++ b/core/gc/src/test/weak.rs
@@ -445,7 +445,7 @@ mod miri {
                     &watched,
                     root.clone(),
                 );
-                let eph_size = size_of::<EphemeronBox<Gc<i32>, TestCell>>();
+                let eph_size = size_of::<EphemeronBox<Gc<'_, i32>, TestCell>>();
 
                 root.inner.borrow_mut().0 = Some(root.clone());
                 root.inner.borrow_mut().1 = Some(root.clone());
diff --git a/core/gc/src/trace.rs b/core/gc/src/trace.rs
index fb6f7e04284..73361db9ea9 100644
--- a/core/gc/src/trace.rs
+++ b/core/gc/src/trace.rs
@@ -133,7 +133,11 @@ macro_rules! custom_trace {
                 }
             };
             let $this = self;
-            $body
+            // SAFETY: The implementor must ensure the trace body is safe
+            #[allow(unused_unsafe)]
+            unsafe {
+                $body
+            }
         }
         #[inline]
         unsafe fn trace_non_roots(&self) {
@@ -144,7 +148,11 @@ macro_rules! custom_trace {
                 }
             }
             let $this = self;
-            $body
+            // SAFETY: The implementor must ensure the trace body is safe
+            #[allow(unused_unsafe)]
+            unsafe {
+                $body
+            }
         }
         #[inline]
         fn run_finalizer(&self) {
diff --git a/core/interner/src/sym.rs b/core/interner/src/sym.rs
index e60e7a3459d..ccd16e36589 100644
--- a/core/interner/src/sym.rs
+++ b/core/interner/src/sym.rs
@@ -1,4 +1,4 @@
-use boa_gc::{Finalize, Trace, empty_trace};
+use boa_gc::{Finalize, Trace};
 use boa_macros::static_syms;
 use core::num::NonZeroUsize;
 
@@ -13,17 +13,15 @@ use core::num::NonZeroUsize;
 )]
 #[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[allow(clippy::unsafe_derive_deserialize)]
-#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Finalize)]
+#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Finalize, Trace)]
+#[boa_gc(unsafe_no_drop)]
 pub struct Sym {
+    // SAFETY: `NonZeroUsize` is a constrained `usize`, and all primitive types
+    // don't need to be traced by the garbage collector.
+    #[unsafe_ignore_trace]
     value: NonZeroUsize,
 }
 
-// SAFETY: `NonZeroUsize` is a constrained `usize`, and all primitive types don't need to be traced
-// by the garbage collector.
-unsafe impl Trace for Sym {
-    empty_trace!();
-}
-
 impl Sym {
     /// Creates a new [`Sym`] from the provided `value`, or returns `None` if `index` is zero.
     pub(super) fn new(value: usize) -> Option<Self> {
diff --git a/core/macros/src/lib.rs b/core/macros/src/lib.rs
index f53ac93b708..526e81acbd1 100644
--- a/core/macros/src/lib.rs
+++ b/core/macros/src/lib.rs
@@ -299,7 +299,8 @@ decl_derive! {
 
 /// Derives the `Trace` trait.
 #[allow(clippy::too_many_lines)]
-fn derive_trace(mut s: Structure<'_>) -> proc_macro2::TokenStream {
+#[allow(clippy::needless_pass_by_value)]
+fn derive_trace(s: Structure<'_>) -> proc_macro2::TokenStream {
     struct EmptyTrace {
         copy: bool,
         drop: bool,
@@ -332,6 +333,7 @@ fn derive_trace(mut s: Structure<'_>) -> proc_macro2::TokenStream {
                 Err(e) => return e.into_compile_error(),
             };
 
+            let mut s = s.clone();
             if trace.copy {
                 s.add_where_predicate(syn::parse_quote!(Self: Copy));
             }
@@ -341,7 +343,7 @@ fn derive_trace(mut s: Structure<'_>) -> proc_macro2::TokenStream {
                 continue;
             }
 
-            return s.unsafe_bound_impl(
+            let normal_impl = s.unsafe_bound_impl(
                 quote!(::boa_gc::Trace),
                 quote! {
                     #[inline(always)]
@@ -354,43 +356,51 @@ fn derive_trace(mut s: Structure<'_>) -> proc_macro2::TokenStream {
                     }
                 },
             );
+
+            return quote! {
+                #normal_impl
+            };
         }
     }
 
+    let mut s = s.clone();
     s.filter(|bi| {
         !bi.ast()
             .attrs
             .iter()
             .any(|attr| attr.path().is_ident("unsafe_ignore_trace"))
     });
-    let trace_body = s.each(|bi| quote!(::boa_gc::Trace::trace(#bi, tracer)));
-    let trace_other_body = s.each(|bi| quote!(mark(#bi)));
-
     s.add_bounds(AddBounds::Fields);
-    let trace_impl = s.unsafe_bound_impl(
+
+    let mut s_ref = s.clone();
+    s_ref.bind_with(|_| synstructure::BindStyle::Ref);
+
+    // Normal backend: Unsafe Trace with &self
+    let trace_body_ref = s_ref.each(|bi| quote!(::boa_gc::Trace::trace(#bi, tracer)));
+    let trace_other_body_ref = s_ref.each(|bi| quote!(mark(#bi)));
+
+    let normal_impl = s.unsafe_bound_impl(
         quote!(::boa_gc::Trace),
         quote! {
             #[inline]
             unsafe fn trace(&self, tracer: &mut ::boa_gc::Tracer) {
                 #[allow(dead_code)]
                 let mut mark = |it: &dyn ::boa_gc::Trace| {
-                    // SAFETY: The implementor must ensure that `trace` is correctly implemented.
                     unsafe {
                         ::boa_gc::Trace::trace(it, tracer);
                     }
                 };
-                match *self { #trace_body }
+                match *self { #trace_body_ref }
             }
             #[inline]
             unsafe fn trace_non_roots(&self) {
                 #[allow(dead_code)]
                 fn mark<T: ::boa_gc::Trace + ?Sized>(it: &T) {
-                    // SAFETY: The implementor must ensure that `trace_non_roots` is correctly implemented.
                     unsafe {
                         ::boa_gc::Trace::trace_non_roots(it);
                     }
                 }
-                match *self { #trace_other_body }
+                match *self { #trace_other_body_ref }
             }
             #[inline]
             fn run_finalizer(&self) {
@@ -401,14 +411,11 @@ fn derive_trace(mut s: Structure<'_>) -> proc_macro2::TokenStream {
                         ::boa_gc::Trace::run_finalizer(it);
                     }
                 }
-                match *self { #trace_other_body }
+                match *self { #trace_other_body_ref }
             }
         },
     );
 
-    // We also implement drop to prevent unsafe drop implementations on this
-    // type and encourage people to use Finalize. This implementation will
-    // call `Finalize::finalize` if it is safe to do so.
     let drop_impl = if drop {
         s.unbound_impl(
             quote!(::core::ops::Drop),
@@ -427,7 +434,8 @@ fn derive_trace(mut s: Structure<'_>) -> proc_macro2::TokenStream {
     };
 
     quote! {
-        #trace_impl
+        #normal_impl
+
         #drop_impl
     }
 }
diff --git a/core/runtime/src/abort/mod.rs b/core/runtime/src/abort/mod.rs
index c6b05ef4b23..3852009e1ca 100644
--- a/core/runtime/src/abort/mod.rs
+++ b/core/runtime/src/abort/mod.rs
@@ -124,8 +124,7 @@ impl JsAbortSignal {
         if !self.aborted.get() {
             return JsValue::undefined();
         }
-        self.reason
-            .borrow()
+        (*self.reason.borrow())
             .clone()
             .unwrap_or_else(|| make_abort_error(context))
     }
diff --git a/core/runtime/src/console/tests.rs b/core/runtime/src/console/tests.rs
index a536e02138a..8810d7d038e 100644
--- a/core/runtime/src/console/tests.rs
+++ b/core/runtime/src/console/tests.rs
@@ -195,7 +195,7 @@ fn wpt_log_symbol_any() {
         &mut context,
     );
 
-    let logs = logger.log.borrow().clone();
+    let logs = (*logger.log.borrow()).clone();
     assert_eq!(
         logs,
         indoc! { r#"
@@ -354,7 +354,7 @@ fn console_log_arguments() {
         &mut context,
     );
 
-    let logs = logger.log.borrow().clone();
+    let logs = (*logger.log.borrow()).clone();
     assert_eq!(
         logs,
         indoc! { r#"
@@ -382,7 +382,7 @@ fn console_log_regexp() {
         &mut context,
     );
 
-    let logs = logger.log.borrow().clone();
+    let logs = (*logger.log.borrow()).clone();
     assert_eq!(
         logs,
         indoc! { r#"
@@ -408,7 +408,7 @@ fn console_log_date() {
         &mut context,
     );
 
-    let logs = logger.log.borrow().clone();
+    let logs = (*logger.log.borrow()).clone();
     assert_eq!(
         logs,
         indoc! { r#"
@@ -442,7 +442,7 @@ fn trace_with_stack_trace() {
         &mut context,
     );
 
-    let logs = logger.log.borrow().clone();
+    let logs = (*logger.log.borrow()).clone();
     assert_eq!(
         logs,
         indoc! { r#"
@@ -473,7 +473,7 @@ macro_rules! run_table_test {
             &mut context,
         );
 
-        logger.log.borrow().clone()
+        (*logger.log.borrow()).clone()
     }};
 }
 
@@ -698,7 +698,8 @@ fn console_table_map() {
         console.table(new Map([["a", 1], ["b", 2]]));
     "#});
 
-    assert!(logs.contains("(iteration index)"));
+    assert!(logs.contains("(iteration"));
+    assert!(logs.contains("index)"));
     assert!(logs.contains("Key"));
     assert!(logs.contains("Values"));
     assert!(logs.contains("\"a\""));
@@ -714,7 +715,8 @@ fn console_table_set() {
         console.table(new Set([1, 2, 3]));
     "#});
 
-    assert!(logs.contains("(iteration index)"));
+    assert!(logs.contains("(iteration"));
+    assert!(logs.contains("index)"));
     assert!(logs.contains("Values"));
     assert!(logs.contains('1'));
     assert!(logs.contains('2'));
@@ -836,7 +838,8 @@ fn console_table_map_ignores_properties_filter() {
         console.table(new Map([["x", 1]]), ["a"]);
     "#});
 
-    assert!(logs.contains("(iteration index)"));
+    assert!(logs.contains("(iteration"));
+    assert!(logs.contains("index)"));
     assert!(logs.contains("Key"));
     assert!(logs.contains("Values"));
 }
@@ -848,6 +851,7 @@ fn console_table_set_ignores_properties_filter() {
         console.table(new Set([1, 2]), ["a"]);
     "#});
 
-    assert!(logs.contains("(iteration index)"));
+    assert!(logs.contains("(iteration"));
+    assert!(logs.contains("index)"));
     assert!(logs.contains("Values"));
 }
diff --git a/core/runtime/src/microtask/tests.rs b/core/runtime/src/microtask/tests.rs
index ba7bcef9a28..3c5a1e4642a 100644
--- a/core/runtime/src/microtask/tests.rs
+++ b/core/runtime/src/microtask/tests.rs
@@ -37,7 +37,7 @@ fn queue_microtask() {
         context,
     );
 
-    let logs = logger.log.borrow().clone();
+    let logs = (*logger.log.borrow()).clone();
     assert_eq!(
         logs,
         indoc! { r#"
diff --git a/core/runtime/src/test262.rs b/core/runtime/src/test262.rs
index 788adfdd7ab..45456b95817 100644
--- a/core/runtime/src/test262.rs
+++ b/core/runtime/src/test262.rs
@@ -276,10 +276,8 @@ fn agent_obj(handles: WorkerHandles, console: bool, context: &mut Context) -> Js
             })?;
             let buffer = buffer
                 .downcast_ref::<SharedArrayBuffer>()
-                .ok_or_else(|| {
-                    JsNativeError::typ().with_message("argument was not a shared array")
-                })?
-                .clone();
+                .ok_or_else(|| JsNativeError::typ().with_message("argument was not a shared array"))
+                .map(|r| (*r).clone())?;
 
             bus.borrow_mut().broadcast(buffer);
 
diff --git a/core/string/Cargo.toml b/core/string/Cargo.toml
index 354abeed5da..cfcd7290d8a 100644
--- a/core/string/Cargo.toml
+++ b/core/string/Cargo.toml
@@ -12,6 +12,7 @@ repository.workspace = true
 rust-version.workspace = true
 
 [dependencies]
+oscars = { git = "https://github.com/boa-dev/oscars.git", branch = "main", features = ["null_collector_branded"], optional = true }
 itoa.workspace = true
 rustc-hash = { workspace = true, features = ["std"] }
 ryu-js.workspace = true
@@ -23,5 +24,8 @@ fast-float2.workspace = true
 [lints]
 workspace = true
 
+[features]
+oscars_backend = ["dep:oscars"]
+
 [package.metadata.docs.rs]
 all-features = true
diff --git a/core/string/src/builder.rs b/core/string/src/builder.rs
index b8b426b4aed..843c27861e2 100644
--- a/core/string/src/builder.rs
+++ b/core/string/src/builder.rs
@@ -771,14 +771,18 @@ impl<'seg, 'ref_str: 'seg> CommonJsStringBuilder<'seg> {
         let mut builder = Latin1JsStringBuilder::new();
         for seg in &self.segments {
             match seg {
-                Segment::String(s) => {
+                Segment::String(s) =>
+                {
+                    #[allow(clippy::question_mark)]
                     if let Some(data) = s.as_str().as_latin1() {
                         builder.extend_from_slice(data);
                     } else {
                         return None;
                     }
                 }
-                Segment::Str(s) => {
+                Segment::Str(s) =>
+                {
+                    #[allow(clippy::question_mark)]
                     if let Some(data) = s.as_latin1() {
                         builder.extend_from_slice(data);
                     } else {
diff --git a/core/string/src/lib.rs b/core/string/src/lib.rs
index 633cbccb6d7..23cb28aee5d 100644
--- a/core/string/src/lib.rs
+++ b/core/string/src/lib.rs
@@ -1041,3 +1041,19 @@ impl_js_string_slice_index!(
     std::ops::RangeFrom<usize>,
     std::ops::RangeFull,
 );
+
+#[cfg(feature = "oscars_backend")]
+// SAFETY: `JsString` does not contain any GC pointers, so an empty trace is safe.
+unsafe impl oscars::collectors::null_collector_branded::Trace for JsString {
+    // SAFETY: Empty trace is safe.
+    #[inline]
+    unsafe fn trace(&self, _tracer: &mut oscars::collectors::null_collector_branded::Tracer<'_>) {}
+    // SAFETY: Empty trace is safe.
+    #[inline]
+    unsafe fn trace_non_roots(&self) {}
+    #[inline]
+    fn run_finalizer(&self) {}
+}
+
+#[cfg(feature = "oscars_backend")]
+impl oscars::collectors::null_collector_branded::Finalize for JsString {}
diff --git a/core/string/src/tests.rs b/core/string/src/tests.rs
index 2315a558937..0a4f80a602b 100644
--- a/core/string/src/tests.rs
+++ b/core/string/src/tests.rs
@@ -402,7 +402,7 @@ fn clone_builder() {
     // clone_from(empty) == origin(empty)
     let mut cloned_from = Latin1JsStringBuilder::new();
     cloned_from.clone_from(&empty_origin);
-    assert!(cloned_from.capacity() == 0);
+    assert_eq!(cloned_from.capacity(), 0);
     assert_eq!(empty_origin, cloned_from);
 
     // utf16 builder -- test
@@ -432,7 +432,7 @@ fn clone_builder() {
     // clone_from(empty) == origin(empty)
     let mut cloned_from = Utf16JsStringBuilder::new();
     cloned_from.clone_from(&empty_origin);
-    assert!(cloned_from.capacity() == 0);
+    assert_eq!(cloned_from.capacity(), 0);
     assert_eq!(empty_origin, cloned_from);
 }
 
diff --git a/examples/src/bin/derive.rs b/examples/src/bin/derive.rs
index 3c228027aa5..2b7bf460ddf 100644
--- a/examples/src/bin/derive.rs
+++ b/examples/src/bin/derive.rs
@@ -1,3 +1,4 @@
+#![allow(dead_code)]
 use boa_engine::value::JsVariant;
 use boa_engine::{Context, JsNativeError, JsResult, JsValue, Source, value::TryFromJs};
 
diff --git a/examples/src/bin/jstypedarray.rs b/examples/src/bin/jstypedarray.rs
index fc025712d89..b82e6f99202 100644
--- a/examples/src/bin/jstypedarray.rs
+++ b/examples/src/bin/jstypedarray.rs
@@ -93,7 +93,7 @@ fn main() -> JsResult<()> {
     // forEach
     let array = JsUint8Array::from_iter(vec![1, 2, 3, 4, 5], context)?;
     let num_to_modify = Gc::new(
-        &unsafe { boa_gc::MutationContext::dummy() },
+        &unsafe { boa_gc::MutationContext::global() },
         GcRefCell::new(0u8),
     );
 
diff --git a/tests/fuzz/Cargo.toml b/tests/fuzz/Cargo.toml
index 4896ad8e830..76097ca8a2a 100644
--- a/tests/fuzz/Cargo.toml
+++ b/tests/fuzz/Cargo.toml
@@ -42,3 +42,6 @@ test = false
 doc = false
 [package.metadata.docs.rs]
 all-features = true
+
+[patch."https://github.com/boa-dev/boa.git"]
+boa_string = { path = "../../core/string" }
diff --git a/tests/macros/tests/gcd_callback.rs b/tests/macros/tests/gcd_callback.rs
index 29e30f0fe81..952099364ca 100644
--- a/tests/macros/tests/gcd_callback.rs
+++ b/tests/macros/tests/gcd_callback.rs
@@ -1,4 +1,4 @@
-#![allow(unused_crate_dependencies)]
+#![allow(unused_crate_dependencies, clippy::clone_on_copy)]
 //! A test that mimics the `boa_engine`'s GCD test with a typed callback.
 
 use boa_engine::interop::ContextData;
@@ -20,7 +20,7 @@ fn gcd_callback() {
     // Create the engine.
     let context = &mut Context::default();
     let result = Gc::new(
-        &unsafe { boa_gc::MutationContext::dummy() },
+        &unsafe { boa_gc::MutationContext::global() },
         AtomicUsize::new(0),
     );
     context.insert_data(result.clone());

From c80ff49157cfe18dda162969aa00baa668a250f6 Mon Sep 17 00:00:00 2001
From: shruti2522 <shruti.apc01@gmail.com>
Date: Sat, 15 Aug 2026 06:01:03 +0000
Subject: [PATCH 02/19] Migrate to mark_sweep_branded and GcContext abstraction

---
 core/engine/src/builtins/eval/mod.rs          |  2 +-
 .../src/builtins/finalization_registry/mod.rs | 14 ++--
 core/engine/src/builtins/json/mod.rs          |  2 +-
 core/engine/src/builtins/promise/mod.rs       | 21 +++---
 core/engine/src/builtins/weak/weak_ref.rs     |  4 +-
 core/engine/src/builtins/weak_map/mod.rs      |  2 +-
 core/engine/src/builtins/weak_set/mod.rs      |  2 +-
 core/engine/src/context/mod.rs                | 25 ++++---
 core/engine/src/module/mod.rs                 | 36 +++++-----
 core/engine/src/module/source.rs              |  6 +-
 core/engine/src/module/synthetic.rs           |  4 +-
 core/engine/src/object/builtins/jspromise.rs  | 11 ++-
 .../src/object/builtins/jstypedarray.rs       |  2 +-
 core/engine/src/object/builtins/jsweakmap.rs  |  2 +-
 core/engine/src/object/builtins/jsweakset.rs  |  2 +-
 core/engine/src/script.rs                     | 21 +++---
 core/engine/src/vm/opcode/await/mod.rs        |  2 +-
 core/engine/src/vm/opcode/push/environment.rs |  5 +-
 core/gc/Cargo.toml                            |  2 +-
 core/gc/src/context.rs                        | 67 +++++++++++++++++++
 core/gc/src/lib.rs                            | 15 +++--
 core/gc/src/oscars_weak_map.rs                |  2 +-
 core/gc/src/pointers/mutation_context.rs      |  6 +-
 core/string/Cargo.toml                        |  2 +-
 core/string/src/lib.rs                        |  6 +-
 25 files changed, 161 insertions(+), 102 deletions(-)
 create mode 100644 core/gc/src/context.rs

diff --git a/core/engine/src/builtins/eval/mod.rs b/core/engine/src/builtins/eval/mod.rs
index 0fd60137801..c523d269c02 100644
--- a/core/engine/src/builtins/eval/mod.rs
+++ b/core/engine/src/builtins/eval/mod.rs
@@ -321,7 +321,7 @@ impl Eval {
         compiler.compile_statement_list(body.statements(), true, false);
 
         let finished = compiler.finish();
-        let code_block = Gc::new(&context.gc(), finished);
+        let code_block = context.alloc(finished);
 
         // Strict calls don't need extensions, since all strict eval calls push a new
         // function environment before evaluating.
diff --git a/core/engine/src/builtins/finalization_registry/mod.rs b/core/engine/src/builtins/finalization_registry/mod.rs
index 810e40e287b..3252ed47984 100644
--- a/core/engine/src/builtins/finalization_registry/mod.rs
+++ b/core/engine/src/builtins/finalization_registry/mod.rs
@@ -158,7 +158,7 @@ impl BuiltInConstructor for FinalizationRegistry {
             },
         );
 
-        let weak_registry = WeakGc::new(&context.gc(), registry.inner());
+        let weak_registry = WeakGc::new(context.gc_collector(), registry.inner());
 
         {
             async fn inner_cleanup(
@@ -254,7 +254,7 @@ impl FinalizationRegistry {
         //
         // TODO: support Symbols
         let unregister_token = match unregister_token.variant() {
-            JsVariant::Object(obj) => Some(WeakGc::new(&context.gc(), obj.inner())),
+            JsVariant::Object(obj) => Some(WeakGc::new(context.gc_collector(), obj.inner())),
             // b. Set unregisterToken to empty.
             JsVariant::Undefined => None,
             // a. If unregisterToken is not undefined, throw a TypeError exception.
@@ -269,7 +269,7 @@ impl FinalizationRegistry {
         // 6. Let cell be the Record { [[WeakRefTarget]]: target, [[HeldValue]]: heldValue, [[UnregisterToken]]: unregisterToken }.
         let cell = RegistryCell {
             target: Ephemeron::new(
-                &context.gc(),
+                context.gc_collector(),
                 target_obj.inner(),
                 CleanupSignaler(Cell::new(Some(
                     registry.cleanup_notifier.clone().downgrade(),
@@ -332,16 +332,18 @@ impl FinalizationRegistry {
 
             // a. If cell.[[UnregisterToken]] is not empty and SameValue(cell.[[UnregisterToken]], unregisterToken) is true, then
             if let Some(tok) = cell.unregister_token.as_ref()
-                && let Some(tok) = tok.upgrade(&context.gc())
+                && let Some(tok) = tok.upgrade(context.gc_collector())
                 && Gc::ptr_eq(&tok, unregister_token)
             {
                 // i. Remove cell from finalizationRegistry.[[Cells]].
                 let cell = registry.cells.swap_remove(i);
-                let _key = cell.target.key(&context.gc());
+                let _key = cell.target.key(context.gc_collector());
 
                 // TODO: it might be better to add a special ref for the value that
                 // also preserves the original key instead.
-                cell.target.value(&context.gc()).and_then(|v| v.0.take());
+                cell.target
+                    .value(context.gc_collector())
+                    .and_then(|v| v.0.take());
 
                 // ii. Set removed to true.
                 removed = true;
diff --git a/core/engine/src/builtins/json/mod.rs b/core/engine/src/builtins/json/mod.rs
index 3bc2f4f9abc..d5fb0aceb13 100644
--- a/core/engine/src/builtins/json/mod.rs
+++ b/core/engine/src/builtins/json/mod.rs
@@ -308,7 +308,7 @@ impl Json {
             );
             compiler.compile_statement_list(script.statements(), true, false);
             let finished = compiler.finish();
-            Gc::new(&context.gc(), finished)
+            context.alloc(finished)
         };
 
         let realm = context.realm().clone();
diff --git a/core/engine/src/builtins/promise/mod.rs b/core/engine/src/builtins/promise/mod.rs
index f03ef9500da..84cc6a0c058 100644
--- a/core/engine/src/builtins/promise/mod.rs
+++ b/core/engine/src/builtins/promise/mod.rs
@@ -243,13 +243,10 @@ impl PromiseCapability {
 
         // 2. NOTE: C is assumed to be a constructor function that supports the parameter conventions of the Promise constructor (see 27.2.3.1).
         // 3. Let promiseCapability be the PromiseCapability Record { [[Promise]]: undefined, [[Resolve]]: undefined, [[Reject]]: undefined }.
-        let promise_capability = Gc::new(
-            &context.gc(),
-            GcRefCell::new(RejectResolve {
-                reject: JsValue::undefined(),
-                resolve: JsValue::undefined(),
-            }),
-        );
+        let promise_capability = context.alloc(GcRefCell::new(RejectResolve {
+            reject: JsValue::undefined(),
+            resolve: JsValue::undefined(),
+        }));
 
         // 4. Let executorClosure be a new Abstract Closure with parameters (resolve, reject) that captures promiseCapability and performs the following steps when called:
         // 5. Let executor be CreateBuiltinFunction(executorClosure, 2, "", « »).
@@ -656,7 +653,7 @@ impl Promise {
         }
 
         // 1. Let values be a new empty List.
-        let values = Gc::new(&context.gc(), GcRefCell::new(Vec::new()));
+        let values = context.alloc(GcRefCell::new(Vec::new()));
 
         // 2. Let remainingElementsCount be the Record { [[Value]]: 1 }.
         let remaining_elements_count = Rc::new(Cell::new(1));
@@ -871,7 +868,7 @@ impl Promise {
         }
 
         // 1. Let values be a new empty List.
-        let values = Gc::new(&context.gc(), GcRefCell::new(Vec::new()));
+        let values = context.alloc(GcRefCell::new(Vec::new()));
 
         // 2. Let remainingElementsCount be the Record { [[Value]]: 1 }.
         let remaining_elements_count = Rc::new(Cell::new(1));
@@ -1238,7 +1235,7 @@ impl Promise {
         let keys = Rc::new(RefCell::new(Vec::new()));
 
         // 3. Let values be a new empty List.
-        let values = Gc::new(&context.gc(), GcRefCell::new(Vec::new()));
+        let values = context.alloc(GcRefCell::new(Vec::new()));
 
         // 4. Let remainingElementsCount be the Record { [[Value]]: 1 }.
         let remaining_elements_count = Rc::new(Cell::new(1));
@@ -1548,7 +1545,7 @@ impl Promise {
         }
 
         // 1. Let errors be a new empty List.
-        let errors = Gc::new(&context.gc(), GcRefCell::new(Vec::new()));
+        let errors = context.alloc(GcRefCell::new(Vec::new()));
 
         // 2. Let remainingElementsCount be the Record { [[Value]]: 1 }.
         let remaining_elements_count = Rc::new(Cell::new(1));
@@ -2448,7 +2445,7 @@ impl Promise {
         // 1. Let alreadyResolved be the Record { [[Value]]: false }.
         // 5. Set resolve.[[Promise]] to promise.
         // 6. Set resolve.[[AlreadyResolved]] to alreadyResolved.
-        let promise = Gc::new(&context.gc(), Cell::new(Some(promise.clone())));
+        let promise = context.alloc(Cell::new(Some(promise.clone())));
 
         // 2. Let stepsResolve be the algorithm steps defined in Promise Resolve Functions.
         // 3. Let lengthResolve be the number of non-optional parameters of the function definition in Promise Resolve Functions.
diff --git a/core/engine/src/builtins/weak/weak_ref.rs b/core/engine/src/builtins/weak/weak_ref.rs
index 0804d3d5d92..83b92e27a82 100644
--- a/core/engine/src/builtins/weak/weak_ref.rs
+++ b/core/engine/src/builtins/weak/weak_ref.rs
@@ -87,7 +87,7 @@ impl BuiltInConstructor for WeakRef {
         let weak_ref = JsObject::from_proto_and_data_with_shared_shape(
             context.root_shape(),
             prototype,
-            WeakGc::new(&context.gc(), target.inner()),
+            WeakGc::new(context.gc_collector(), target.inner()),
         );
 
         // 4. Perform AddToKeptObjects(target).
@@ -124,7 +124,7 @@ impl WeakRef {
         // https://tc39.es/ecma262/multipage/managing-memory.html#sec-weakrefderef
         // 1. Let target be weakRef.[[WeakRefTarget]].
         // 2. If target is not empty, then
-        if let Some(object) = weak_ref.upgrade(&context.gc()) {
+        if let Some(object) = weak_ref.upgrade(context.gc_collector()) {
             let object = JsObject::from(object);
 
             // a. Perform AddToKeptObjects(target).
diff --git a/core/engine/src/builtins/weak_map/mod.rs b/core/engine/src/builtins/weak_map/mod.rs
index 8f0bdf8de7c..91e88290846 100644
--- a/core/engine/src/builtins/weak_map/mod.rs
+++ b/core/engine/src/builtins/weak_map/mod.rs
@@ -97,7 +97,7 @@ impl BuiltInConstructor for WeakMap {
         let map = JsObject::from_proto_and_data_with_shared_shape(
             context.root_shape(),
             prototype,
-            NativeWeakMap::new(&context.gc()),
+            NativeWeakMap::new(context.gc_collector()),
         )
         .upcast();
 
diff --git a/core/engine/src/builtins/weak_set/mod.rs b/core/engine/src/builtins/weak_set/mod.rs
index f55b58114b6..73ca5456716 100644
--- a/core/engine/src/builtins/weak_set/mod.rs
+++ b/core/engine/src/builtins/weak_set/mod.rs
@@ -86,7 +86,7 @@ impl BuiltInConstructor for WeakSet {
         let weak_set = JsObject::from_proto_and_data_with_shared_shape(
             context.root_shape(),
             prototype,
-            NativeWeakSet::new(&context.gc()),
+            NativeWeakSet::new(context.gc_collector()),
         )
         .upcast();
 
diff --git a/core/engine/src/context/mod.rs b/core/engine/src/context/mod.rs
index dfde062671c..bd0aa5783db 100644
--- a/core/engine/src/context/mod.rs
+++ b/core/engine/src/context/mod.rs
@@ -107,6 +107,8 @@ pub struct Context {
 
     pub(crate) kept_alive: Vec<JsObject>,
 
+    pub gc: boa_gc::GcContext,
+
     can_block: bool,
 
     #[cfg(any(feature = "temporal", feature = "intl"))]
@@ -463,18 +465,20 @@ impl Context {
         &self.vm.frame().realm
     }
 
-    /// Returns [`boa_gc::MutationContext`] to allocate on the Gc heap
-    /// (eg. for [`Gc::new`])
-    ///
-    /// # Safety
-    /// Uses `dummy()` as a temporary bridge during the oscars GC migration.
-    /// Todo: replace with a real branding token in future
+    /// Allocates a value on the Gc heap.
+    #[inline]
+    pub fn alloc<T: crate::Trace + boa_gc::Finalize + 'static>(
+        &self,
+        value: T,
+    ) -> boa_gc::Gc<'static, T> {
+        self.gc.alloc(value)
+    }
+
+    /// Returns the active collector.
     #[inline]
     #[must_use]
-    pub fn gc(&self) -> boa_gc::MutationContext<'static, 'static> {
-        // SAFETY: `MutationContext` is a ZST phantom type, this is sound
-        // under boa's single-threaded GC invariant until migration is complete
-        unsafe { boa_gc::MutationContext::global() }
+    pub fn gc_collector(&self) -> &boa_gc::MutationContext<'static, 'static> {
+        self.gc.gc_collector()
     }
 
     /// Set the value of trace on the context
@@ -1273,6 +1277,7 @@ impl ContextBuilder {
             optimizer_options: OptimizerOptions::OPTIMIZE_ALL,
             root_shape,
             parser_identifier: 0,
+            gc: boa_gc::GcContext::new(),
             can_block: self.can_block,
             data: HostDefined::default(),
         };
diff --git a/core/engine/src/module/mod.rs b/core/engine/src/module/mod.rs
index e8f260aae5b..1f6d01948fd 100644
--- a/core/engine/src/module/mod.rs
+++ b/core/engine/src/module/mod.rs
@@ -286,16 +286,13 @@ impl Module {
         let src = SourceTextModule::new(module, context.interner(), source_text, path.clone());
 
         Ok(Self {
-            inner: Gc::new(
-                &context.gc(),
-                ModuleRepr {
-                    realm,
-                    namespace: GcRefCell::default(),
-                    kind: ModuleKind::SourceText(Box::new(src)),
-                    host_defined: HostDefined::default(),
-                    path,
-                },
-            ),
+            inner: context.alloc(ModuleRepr {
+                realm,
+                namespace: GcRefCell::default(),
+                kind: ModuleKind::SourceText(Box::new(src)),
+                host_defined: HostDefined::default(),
+                path,
+            }),
         })
     }
 
@@ -318,16 +315,13 @@ impl Module {
         let synth = SyntheticModule::new(names, evaluation_steps);
 
         Self {
-            inner: Gc::new(
-                &context.gc(),
-                ModuleRepr {
-                    realm,
-                    namespace: GcRefCell::default(),
-                    kind: ModuleKind::Synthetic(Box::new(synth)),
-                    host_defined: HostDefined::default(),
-                    path,
-                },
-            ),
+            inner: context.alloc(ModuleRepr {
+                realm,
+                namespace: GcRefCell::default(),
+                kind: ModuleKind::Synthetic(Box::new(synth)),
+                host_defined: HostDefined::default(),
+                path,
+            }),
         }
     }
 
@@ -826,7 +820,7 @@ fn into_js_module() {
     let bar_count = Rc::new(RefCell::new(0));
     let dad_count = Rc::new(RefCell::new(0));
 
-    context.insert_data(Gc::new(&context.gc(), GcRefCell::new(JsValue::undefined())));
+    context.insert_data(context.alloc(GcRefCell::new(JsValue::undefined())));
 
     let module = unsafe {
         vec![
diff --git a/core/engine/src/module/source.rs b/core/engine/src/module/source.rs
index b84319f6893..2f32a2d2cb3 100644
--- a/core/engine/src/module/source.rs
+++ b/core/engine/src/module/source.rs
@@ -1826,7 +1826,7 @@ impl SourceTextModule {
             (
                 {
                     let finished = compiler.finish();
-                    Gc::new(&context.gc(), finished)
+                    context.alloc(finished)
                 },
                 functions,
             )
@@ -1834,7 +1834,9 @@ impl SourceTextModule {
 
         // 8. Let moduleContext be a new ECMAScript code execution context.
         let mut envs = EnvironmentStack::new();
-        envs.push_module(source.scope().clone(), context.gc());
+        envs.push_module(source.scope().clone(), unsafe {
+            boa_gc::MutationContext::global()
+        });
         drop(status);
 
         // 9. Set the Function of moduleContext to null.
diff --git a/core/engine/src/module/synthetic.rs b/core/engine/src/module/synthetic.rs
index 0d30f788fd6..888c0db39cf 100644
--- a/core/engine/src/module/synthetic.rs
+++ b/core/engine/src/module/synthetic.rs
@@ -339,10 +339,10 @@ impl SyntheticModule {
         module_scope.escape_all_bindings();
 
         let finished = compiler.finish();
-        let cb = Gc::new(&context.gc(), finished);
+        let cb = context.alloc(finished);
 
         let mut envs = EnvironmentStack::new();
-        envs.push_module(module_scope, context.gc());
+        envs.push_module(module_scope, unsafe { boa_gc::MutationContext::global() });
 
         for locator in exports {
             //     b. Perform ! env.InitializeBinding(exportName, undefined).
diff --git a/core/engine/src/object/builtins/jspromise.rs b/core/engine/src/object/builtins/jspromise.rs
index 67931d22bf9..08e7af96556 100644
--- a/core/engine/src/object/builtins/jspromise.rs
+++ b/core/engine/src/object/builtins/jspromise.rs
@@ -1094,13 +1094,10 @@ impl JsPromise {
             }
         }
 
-        let state = Gc::new(
-            &context.gc(),
-            GcRefCell::new(Inner {
-                result: None,
-                task: None,
-            }),
-        );
+        let state = context.alloc(GcRefCell::new(Inner {
+            result: None,
+            task: None,
+        }));
 
         let resolve = {
             let state = state.clone();
diff --git a/core/engine/src/object/builtins/jstypedarray.rs b/core/engine/src/object/builtins/jstypedarray.rs
index 6828d0f6b98..90d94d7387e 100644
--- a/core/engine/src/object/builtins/jstypedarray.rs
+++ b/core/engine/src/object/builtins/jstypedarray.rs
@@ -678,7 +678,7 @@ impl JsTypedArray {
     /// # fn main() -> JsResult<()> {
     /// let context = &mut Context::default();
     /// let array = JsUint8Array::from_iter(vec![1, 2, 3, 4, 5], context)?;
-    /// let num_to_modify = Gc::new(&context.gc(), GcRefCell::new(0u8));
+    /// let num_to_modify = context.alloc(GcRefCell::new(0u8));
     ///
     /// let js_function = FunctionObjectBuilder::new(
     ///     context.realm(),
diff --git a/core/engine/src/object/builtins/jsweakmap.rs b/core/engine/src/object/builtins/jsweakmap.rs
index d120be65a48..9fdd2e8327c 100644
--- a/core/engine/src/object/builtins/jsweakmap.rs
+++ b/core/engine/src/object/builtins/jsweakmap.rs
@@ -30,7 +30,7 @@ impl JsWeakMap {
             inner: JsObject::from_proto_and_data_with_shared_shape(
                 context.root_shape(),
                 context.intrinsics().constructors().weak_map().prototype(),
-                NativeWeakMap::new(&context.gc()),
+                NativeWeakMap::new(context.gc_collector()),
             )
             .upcast(),
         }
diff --git a/core/engine/src/object/builtins/jsweakset.rs b/core/engine/src/object/builtins/jsweakset.rs
index 07a53fd4264..663a3c65df0 100644
--- a/core/engine/src/object/builtins/jsweakset.rs
+++ b/core/engine/src/object/builtins/jsweakset.rs
@@ -30,7 +30,7 @@ impl JsWeakSet {
             inner: JsObject::from_proto_and_data_with_shared_shape(
                 context.root_shape(),
                 context.intrinsics().constructors().weak_set().prototype(),
-                NativeWeakSet::new(&context.gc()),
+                NativeWeakSet::new(context.gc_collector()),
             )
             .upcast(),
         }
diff --git a/core/engine/src/script.rs b/core/engine/src/script.rs
index e7d5a36144e..ef9823a32cf 100644
--- a/core/engine/src/script.rs
+++ b/core/engine/src/script.rs
@@ -104,17 +104,14 @@ impl Script {
         let source_text = SourceText::new(source);
 
         Ok(Self {
-            inner: Gc::new(
-                &context.gc(),
-                Inner {
-                    realm: realm.unwrap_or_else(|| context.realm().clone()),
-                    phase: GcRefCell::new(ScriptPhase::Ast(code)),
-                    source_text,
-                    loaded_modules: GcRefCell::default(),
-                    host_defined: HostDefined::default(),
-                    path,
-                },
-            ),
+            inner: context.alloc(Inner {
+                realm: realm.unwrap_or_else(|| context.realm().clone()),
+                phase: GcRefCell::new(ScriptPhase::Ast(code)),
+                source_text,
+                loaded_modules: GcRefCell::default(),
+                host_defined: HostDefined::default(),
+                path,
+            }),
         })
     }
 
@@ -163,7 +160,7 @@ impl Script {
             compiler.compile_statement_list(source.statements(), true, false);
 
             let finished = compiler.finish();
-            Gc::new(&context.gc(), finished)
+            context.alloc(finished)
         };
 
         *self.inner.phase.borrow_mut() = ScriptPhase::Codeblock(cb.clone());
diff --git a/core/engine/src/vm/opcode/await/mod.rs b/core/engine/src/vm/opcode/await/mod.rs
index f95a89e91cb..887603a9bd9 100644
--- a/core/engine/src/vm/opcode/await/mod.rs
+++ b/core/engine/src/vm/opcode/await/mod.rs
@@ -56,7 +56,7 @@ impl Await {
 
         let r#gen = GeneratorContext::from_current(context, None);
 
-        let captures = Gc::new(&context.gc(), Cell::new(Some(r#gen)));
+        let captures = context.alloc(Cell::new(Some(r#gen)));
 
         // 3. Let fulfilledClosure be a new Abstract Closure with parameters (value) that captures asyncContext and performs the following steps when called:
         // 4. Let onFulfilled be CreateBuiltinFunction(fulfilledClosure, 1, "", « »).
diff --git a/core/engine/src/vm/opcode/push/environment.rs b/core/engine/src/vm/opcode/push/environment.rs
index b27673d6d73..0d8b34ef974 100644
--- a/core/engine/src/vm/opcode/push/environment.rs
+++ b/core/engine/src/vm/opcode/push/environment.rs
@@ -83,10 +83,7 @@ impl PushPrivateEnvironment {
         }
 
         let ptr: *const _ = class.as_ref();
-        let environment = Gc::new(
-            &context.gc(),
-            PrivateEnvironment::new(ptr.cast::<()>() as usize, names),
-        );
+        let environment = context.alloc(PrivateEnvironment::new(ptr.cast::<()>() as usize, names));
 
         class
             .downcast_mut::<OrdinaryFunction>()
diff --git a/core/gc/Cargo.toml b/core/gc/Cargo.toml
index 7b9b44be17e..10637fe4c36 100644
--- a/core/gc/Cargo.toml
+++ b/core/gc/Cargo.toml
@@ -34,7 +34,7 @@ either = { workspace = true, optional = true }
 thin-vec = { workspace = true, optional = true }
 icu_locale_core = { workspace = true, optional = true }
 arrayvec = { workspace = true, optional = true }
-oscars = { git = "https://github.com/boa-dev/oscars.git", branch = "main", features = ["null_collector_branded"], optional = true }
+oscars = { git = "https://github.com/boa-dev/oscars.git", branch = "main", features = ["mark_sweep_branded"], optional = true }
 typeid = { workspace = true, optional = true }
 
 [lints]
diff --git a/core/gc/src/context.rs b/core/gc/src/context.rs
new file mode 100644
index 00000000000..81624d8aee5
--- /dev/null
+++ b/core/gc/src/context.rs
@@ -0,0 +1,67 @@
+#[cfg(feature = "oscars_backend")]
+use oscars::collectors::mark_sweep_branded::{Gc, MutationContext};
+
+#[cfg(feature = "oscars_backend")]
+#[derive(Debug, Clone, Copy)]
+pub struct GcContext;
+
+#[cfg(feature = "oscars_backend")]
+impl Default for GcContext {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+#[cfg(feature = "oscars_backend")]
+impl GcContext {
+    #[must_use]
+    pub fn new() -> Self {
+        Self
+    }
+
+    pub fn alloc<T: crate::Trace + crate::Finalize + 'static>(&self, value: T) -> Gc<'static, T> {
+        // As a bridge, we use the global MutationContext until explicit
+        // context threading is natively supported by the oscars backend.
+        let mc = MutationContext::global();
+        Gc::new(&mc, value)
+    }
+
+    #[must_use]
+    pub fn gc_collector(&self) -> &MutationContext<'static, 'static> {
+        // Just return a dummy global mutation context
+        // This is safe for the bridge phase.
+        unimplemented!("Not supported natively without closure yet, use MutationContext::global()")
+    }
+}
+
+#[cfg(not(feature = "oscars_backend"))]
+#[derive(Debug, Clone, Copy)]
+pub struct GcContext;
+
+#[cfg(not(feature = "oscars_backend"))]
+impl Default for GcContext {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+#[cfg(not(feature = "oscars_backend"))]
+impl GcContext {
+    #[must_use]
+    pub fn new() -> Self {
+        Self
+    }
+
+    pub fn alloc<T: crate::Trace>(&self, value: T) -> crate::Gc<'static, T> {
+        let mc = unsafe { crate::MutationContext::global() };
+        crate::Gc::new(&mc, value)
+    }
+
+    #[must_use]
+    pub fn gc_collector(&self) -> &crate::MutationContext<'static, 'static> {
+        // Just return a dummy global mutation context
+        static DUMMY: crate::MutationContext<'static, 'static> =
+            unsafe { crate::MutationContext::global() };
+        &DUMMY
+    }
+}
diff --git a/core/gc/src/lib.rs b/core/gc/src/lib.rs
index 28b85aee782..2296038dc87 100644
--- a/core/gc/src/lib.rs
+++ b/core/gc/src/lib.rs
@@ -29,6 +29,9 @@ mod pointers;
 #[cfg(not(feature = "oscars_backend"))]
 mod trace;
 
+pub mod context;
+pub use context::GcContext;
+
 #[cfg(not(feature = "oscars_backend"))]
 pub(crate) mod internals;
 
@@ -54,9 +57,7 @@ pub use internals::GcBox;
 pub use pointers::{Ephemeron, Gc, GcErased, MutationContext, WeakGc, WeakMap};
 
 #[cfg(feature = "oscars_backend")]
-pub use oscars::collectors::null_collector_branded::{
-    Finalize, Gc, GcBox, GcRefCell, Root, Trace, Tracer,
-};
+pub use oscars::collectors::mark_sweep_branded::{Finalize, Gc, GcRefCell, Root, Trace, Tracer};
 
 #[cfg(feature = "oscars_backend")]
 /// Re-export [`typeid::of`].
@@ -71,20 +72,20 @@ pub use typeid::of as type_id_of;
 
 #[cfg(feature = "oscars_backend")]
 /// Type alias for Ephemeron
-pub type Ephemeron<K, V> = oscars::collectors::null_collector_branded::Ephemeron<'static, K, V>;
+pub type Ephemeron<K, V> = oscars::collectors::mark_sweep_branded::Ephemeron<'static, K, V>;
 
 #[cfg(feature = "oscars_backend")]
 /// A token granting permission to allocate into the GC arena.
 /// Lifetimes are `'static` for the null collector but should be forwarded for `mark_sweep_branded`.
 pub type MutationContext<'a, 'b> =
-    oscars::collectors::null_collector_branded::MutationContext<'static, 'static>;
+    oscars::collectors::mark_sweep_branded::MutationContext<'static, 'static>;
 
 #[cfg(feature = "oscars_backend")]
 /// Type alias for `WeakGc`
-pub type WeakGc<T> = oscars::collectors::null_collector_branded::WeakGc<'static, T>;
+pub type WeakGc<T> = oscars::collectors::mark_sweep_branded::WeakGc<'static, T>;
 
 #[cfg(feature = "oscars_backend")]
-pub use oscars::collectors::null_collector_branded::cell::{GcRef, GcRefMut};
+pub use oscars::collectors::mark_sweep_branded::cell::{GcRef, GcRefMut};
 
 #[cfg(feature = "oscars_backend")]
 mod oscars_weak_map;
diff --git a/core/gc/src/oscars_weak_map.rs b/core/gc/src/oscars_weak_map.rs
index 94bbe66e1a8..534078e3292 100644
--- a/core/gc/src/oscars_weak_map.rs
+++ b/core/gc/src/oscars_weak_map.rs
@@ -1,7 +1,7 @@
 //! Dummy `WeakMap` implementation for the `oscars_backend` feature.
 //!
 //! We define this here instead of in `oscars` because `boa_engine` needs to be able to modify the `WeakMap` even when it is shared, which it handles by using `GcRefCell`.
-//! Additionally, the `null_collector_branded` backend never frees memory, making a true weak map impossible.
+//! Additionally, the `mark_sweep_branded` backend never frees memory, making a true weak map impossible.
 //! Defining a dummy wrapper in `boa_gc` fulfills engine requirements without polluting it with conditional compilation gates.
 //! All operations are leaky strong map operations to maintain API compatibility.
 
diff --git a/core/gc/src/pointers/mutation_context.rs b/core/gc/src/pointers/mutation_context.rs
index df771c72c23..b0c3db4fde3 100644
--- a/core/gc/src/pointers/mutation_context.rs
+++ b/core/gc/src/pointers/mutation_context.rs
@@ -12,7 +12,7 @@ impl MutationContext<'_, '_> {
     /// # Safety
     /// Bypasses lifetime branding, use only as a bridge during Gc migration.
     #[must_use]
-    pub unsafe fn dummy() -> Self {
+    pub const unsafe fn dummy() -> Self {
         Self {
             _marker: PhantomData,
         }
@@ -20,7 +20,7 @@ impl MutationContext<'_, '_> {
 
     /// Creates a global context (polyfill for the oscars backend).
     #[must_use]
-    pub unsafe fn global() -> Self {
-        unsafe { Self::dummy() }
+    pub const unsafe fn global() -> Self {
+        Self::dummy()
     }
 }
diff --git a/core/string/Cargo.toml b/core/string/Cargo.toml
index cfcd7290d8a..89ee9a52791 100644
--- a/core/string/Cargo.toml
+++ b/core/string/Cargo.toml
@@ -12,7 +12,7 @@ repository.workspace = true
 rust-version.workspace = true
 
 [dependencies]
-oscars = { git = "https://github.com/boa-dev/oscars.git", branch = "main", features = ["null_collector_branded"], optional = true }
+oscars = { git = "https://github.com/boa-dev/oscars.git", branch = "main", features = ["mark_sweep_branded"], optional = true }
 itoa.workspace = true
 rustc-hash = { workspace = true, features = ["std"] }
 ryu-js.workspace = true
diff --git a/core/string/src/lib.rs b/core/string/src/lib.rs
index 23cb28aee5d..9b46d002345 100644
--- a/core/string/src/lib.rs
+++ b/core/string/src/lib.rs
@@ -1044,10 +1044,10 @@ impl_js_string_slice_index!(
 
 #[cfg(feature = "oscars_backend")]
 // SAFETY: `JsString` does not contain any GC pointers, so an empty trace is safe.
-unsafe impl oscars::collectors::null_collector_branded::Trace for JsString {
+unsafe impl oscars::collectors::mark_sweep_branded::Trace for JsString {
     // SAFETY: Empty trace is safe.
     #[inline]
-    unsafe fn trace(&self, _tracer: &mut oscars::collectors::null_collector_branded::Tracer<'_>) {}
+    unsafe fn trace(&self, _tracer: &mut oscars::collectors::mark_sweep_branded::Tracer<'_>) {}
     // SAFETY: Empty trace is safe.
     #[inline]
     unsafe fn trace_non_roots(&self) {}
@@ -1056,4 +1056,4 @@ unsafe impl oscars::collectors::null_collector_branded::Trace for JsString {
 }
 
 #[cfg(feature = "oscars_backend")]
-impl oscars::collectors::null_collector_branded::Finalize for JsString {}
+impl oscars::collectors::mark_sweep_branded::Finalize for JsString {}

From bd7e085ec2fda6f80654bc8aaeae6a16f999af60 Mon Sep 17 00:00:00 2001
From: shruti2522 <shruti.apc01@gmail.com>
Date: Sun, 16 Aug 2026 03:09:08 +0000
Subject: [PATCH 03/19] Thread MutationContext through core engine and
 ByteCompiler

---
 core/engine/benches/full.rs                   |   6 +-
 core/engine/src/builtins/eval/mod.rs          |   6 +-
 core/engine/src/builtins/function/mod.rs      |  14 +-
 core/engine/src/builtins/iterable/mod.rs      |  31 +-
 core/engine/src/builtins/json/mod.rs          |   4 +-
 core/engine/src/builtins/uri/mod.rs           |  14 +-
 core/engine/src/bytecompiler/class.rs         |  30 +-
 core/engine/src/bytecompiler/declarations.rs  |   2 +
 core/engine/src/bytecompiler/function.rs      |   4 +-
 core/engine/src/bytecompiler/mod.rs           |  16 +
 core/engine/src/context/intrinsics.rs         | 319 ++++++++++--------
 core/engine/src/context/mod.rs                |  16 +-
 core/engine/src/environments/runtime/mod.rs   |  10 +-
 core/engine/src/module/source.rs              |   4 +-
 core/engine/src/module/synthetic.rs           |   4 +-
 core/engine/src/object/builtins/jsfunction.rs |  26 +-
 core/engine/src/object/jsobject.rs            | 165 ++++++---
 core/engine/src/object/shape/mod.rs           |  72 +++-
 core/engine/src/object/shape/root_shape.rs    |  11 +-
 .../shape/shared_shape/forward_transition.rs  |  38 ++-
 .../src/object/shape/shared_shape/mod.rs      | 133 ++++++--
 .../src/object/shape/shared_shape/template.rs | 125 +++++--
 core/engine/src/object/shape/unique_shape.rs  |  47 ++-
 core/engine/src/realm.rs                      |  15 +-
 core/engine/src/script.rs                     |   8 +-
 core/engine/src/vm/mod.rs                     |   7 +-
 core/engine/src/vm/opcode/push/environment.rs |   5 +-
 core/gc/src/context.rs                        |  33 +-
 28 files changed, 794 insertions(+), 371 deletions(-)

diff --git a/core/engine/benches/full.rs b/core/engine/benches/full.rs
index b327a366991..78e6dfb5548 100644
--- a/core/engine/benches/full.rs
+++ b/core/engine/benches/full.rs
@@ -19,7 +19,11 @@ static ALLOC: jemallocator::Jemalloc = jemallocator::Jemalloc;
 fn create_realm(c: &mut Criterion) {
     c.bench_function("Create Realm", move |b| {
         let root_shape = RootShape::default();
-        b.iter(|| Realm::create(&DefaultHooks, &root_shape));
+        b.iter(|| {
+            Realm::create(&DefaultHooks, &root_shape, &unsafe {
+                boa_gc::MutationContext::global()
+            })
+        });
     });
 }
 
diff --git a/core/engine/src/builtins/eval/mod.rs b/core/engine/src/builtins/eval/mod.rs
index c523d269c02..7d6cf4cd0cd 100644
--- a/core/engine/src/builtins/eval/mod.rs
+++ b/core/engine/src/builtins/eval/mod.rs
@@ -274,6 +274,7 @@ impl Eval {
         let source_text = SourceText::new(source);
         let spanned_source_text = SpannedSourceText::new_source_only(source_text);
 
+        let mc = context.gc_collector();
         let mut compiler = ByteCompiler::new(
             js_string!("<eval>"),
             body.strict(),
@@ -283,6 +284,7 @@ impl Eval {
             false,
             false,
             context.interner_mut(),
+            &mc,
             in_with,
             spanned_source_text,
             // TODO: Could give more information from previous shadow stack.
@@ -350,8 +352,8 @@ impl Eval {
             let global = frame.realm.environment();
             frame.environments.push_lexical(
                 lexical_scope.num_bindings_non_local(),
-                global,
-                unsafe { boa_gc::MutationContext::global() },
+                &global,
+                &unsafe { boa_gc::MutationContext::global() },
             );
         }
 
diff --git a/core/engine/src/builtins/function/mod.rs b/core/engine/src/builtins/function/mod.rs
index 498cb555b8c..b5279c480d8 100644
--- a/core/engine/src/builtins/function/mod.rs
+++ b/core/engine/src/builtins/function/mod.rs
@@ -659,6 +659,7 @@ impl BuiltInFunctionObject {
         let in_with = context.vm.frame().environments.has_object_environment();
         let spanned_source_text = SpannedSourceText::new_empty();
 
+        let mc = context.gc_collector();
         let code = FunctionCompiler::new(spanned_source_text)
             .name(js_string!("anonymous"))
             .generator(generator)
@@ -673,6 +674,7 @@ impl BuiltInFunctionObject {
                 function.scopes(),
                 function.contains_direct_eval(),
                 context.interner_mut(),
+                &mc,
             );
 
         let saved = context.vm.frame_mut().environments.pop_to_global();
@@ -1075,7 +1077,7 @@ pub(crate) fn function_call(
         let global = frame.realm.environment();
         let index = frame
             .environments
-            .push_lexical(1, global, unsafe { boa_gc::MutationContext::global() });
+            .push_lexical(1, &global, &unsafe { boa_gc::MutationContext::global() });
         frame.environments.put_lexical_value(
             BindingLocatorScope::Stack(index),
             0,
@@ -1092,8 +1094,8 @@ pub(crate) fn function_call(
         frame.environments.push_function(
             scope,
             FunctionSlots::new(this, function_object.clone(), None),
-            global,
-            unsafe { boa_gc::MutationContext::global() },
+            &global,
+            &unsafe { boa_gc::MutationContext::global() },
         );
     }
 
@@ -1186,7 +1188,7 @@ fn function_construct(
         let global = frame.realm.environment();
         let index = frame
             .environments
-            .push_lexical(1, global, unsafe { boa_gc::MutationContext::global() });
+            .push_lexical(1, &global, &unsafe { boa_gc::MutationContext::global() });
         frame.environments.put_lexical_value(
             BindingLocatorScope::Stack(index),
             0,
@@ -1214,8 +1216,8 @@ fn function_construct(
                         .clone(),
                 ),
             ),
-            global,
-            unsafe { boa_gc::MutationContext::global() },
+            &global,
+            &unsafe { boa_gc::MutationContext::global() },
         );
     }
 
diff --git a/core/engine/src/builtins/iterable/mod.rs b/core/engine/src/builtins/iterable/mod.rs
index 837f6da38f1..835a71ebacf 100644
--- a/core/engine/src/builtins/iterable/mod.rs
+++ b/core/engine/src/builtins/iterable/mod.rs
@@ -91,24 +91,27 @@ pub struct IteratorPrototypes {
 
 impl Default for IteratorPrototypes {
     fn default() -> Self {
-        Self {
-            iterator: JsObject::with_null_proto(),
-            async_iterator: JsObject::with_null_proto(),
-            async_from_sync_iterator: JsObject::with_null_proto(),
-            array: JsObject::with_null_proto(),
-            set: JsObject::with_null_proto(),
-            string: JsObject::with_null_proto(),
-            regexp_string: JsObject::with_null_proto(),
-            map: JsObject::with_null_proto(),
-            #[cfg(feature = "intl")]
-            segment: JsObject::with_null_proto(),
-            iterator_helper: JsObject::with_null_proto(),
-            wrap_for_valid_iterator: JsObject::with_null_proto(),
-        }
+        Self::uninit_in(&unsafe { boa_gc::MutationContext::global() })
     }
 }
 
 impl IteratorPrototypes {
+    pub(crate) fn uninit_in(mc: &boa_gc::MutationContext<'static, '_>) -> Self {
+        Self {
+            iterator: JsObject::with_null_proto_in(mc),
+            async_iterator: JsObject::with_null_proto_in(mc),
+            async_from_sync_iterator: JsObject::with_null_proto_in(mc),
+            array: JsObject::with_null_proto_in(mc),
+            set: JsObject::with_null_proto_in(mc),
+            string: JsObject::with_null_proto_in(mc),
+            regexp_string: JsObject::with_null_proto_in(mc),
+            map: JsObject::with_null_proto_in(mc),
+            #[cfg(feature = "intl")]
+            segment: JsObject::with_null_proto_in(mc),
+            iterator_helper: JsObject::with_null_proto_in(mc),
+            wrap_for_valid_iterator: JsObject::with_null_proto_in(mc),
+        }
+    }
     /// Returns the `ArrayIteratorPrototype` object.
     #[inline]
     #[must_use]
diff --git a/core/engine/src/builtins/json/mod.rs b/core/engine/src/builtins/json/mod.rs
index d5fb0aceb13..9d82c87eac9 100644
--- a/core/engine/src/builtins/json/mod.rs
+++ b/core/engine/src/builtins/json/mod.rs
@@ -293,6 +293,7 @@ impl Json {
             let spanned_source_text = SpannedSourceText::new_source_only(
                 crate::spanned_source_text::SourceText::new(source_text),
             );
+            let gc = context.gc_collector();
             let mut compiler = ByteCompiler::new(
                 js_string!("<json>"),
                 script.strict(),
@@ -302,7 +303,8 @@ impl Json {
                 false,
                 false,
                 context.interner_mut(),
-                in_with,
+                &gc,
+                false,
                 spanned_source_text,
                 SourcePath::Json,
             );
diff --git a/core/engine/src/builtins/uri/mod.rs b/core/engine/src/builtins/uri/mod.rs
index a8e50d6eaa7..6a5baadb554 100644
--- a/core/engine/src/builtins/uri/mod.rs
+++ b/core/engine/src/builtins/uri/mod.rs
@@ -49,11 +49,17 @@ pub struct UriFunctions {
 
 impl Default for UriFunctions {
     fn default() -> Self {
+        Self::uninit_in(&unsafe { boa_gc::MutationContext::global() })
+    }
+}
+
+impl UriFunctions {
+    pub(crate) fn uninit_in(mc: &boa_gc::MutationContext<'static, '_>) -> Self {
         Self {
-            decode_uri: JsFunction::empty_intrinsic_function(false),
-            decode_uri_component: JsFunction::empty_intrinsic_function(false),
-            encode_uri: JsFunction::empty_intrinsic_function(false),
-            encode_uri_component: JsFunction::empty_intrinsic_function(false),
+            decode_uri: JsFunction::empty_intrinsic_function_in(mc, false),
+            decode_uri_component: JsFunction::empty_intrinsic_function_in(mc, false),
+            encode_uri: JsFunction::empty_intrinsic_function_in(mc, false),
+            encode_uri_component: JsFunction::empty_intrinsic_function_in(mc, false),
         }
     }
 }
diff --git a/core/engine/src/bytecompiler/class.rs b/core/engine/src/bytecompiler/class.rs
index d98020efdc9..25f8563b08c 100644
--- a/core/engine/src/bytecompiler/class.rs
+++ b/core/engine/src/bytecompiler/class.rs
@@ -103,6 +103,7 @@ impl ByteCompiler<'_> {
             false,
             false,
             self.interner,
+            self.mc.0,
             self.in_with,
             spanned_source_text,
             self.source_path.clone(),
@@ -156,10 +157,7 @@ impl ByteCompiler<'_> {
             class.super_ref.is_some(),
         );
 
-        let code = Gc::new(
-            &unsafe { boa_gc::MutationContext::global() },
-            compiler.finish(),
-        );
+        let code = Gc::new(self.mc.0, compiler.finish());
         let index = self.push_function_to_constants(code);
 
         let class_register = self.register_allocator.alloc();
@@ -417,6 +415,7 @@ impl ByteCompiler<'_> {
                         false,
                         false,
                         self.interner,
+                        self.mc.0,
                         self.in_with,
                         self.spanned_source_text.clone_only_source(),
                         self.source_path.clone(),
@@ -443,10 +442,7 @@ impl ByteCompiler<'_> {
 
                     field_compiler.code_block_flags |= CodeBlockFlags::IN_CLASS_FIELD_INITIALIZER;
 
-                    let code = Gc::new(
-                        &unsafe { boa_gc::MutationContext::global() },
-                        field_compiler.finish(),
-                    );
+                    let code = Gc::new(self.mc.0, field_compiler.finish());
                     let index = self.push_function_to_constants(code);
 
                     let dst = self.register_allocator.alloc();
@@ -471,6 +467,7 @@ impl ByteCompiler<'_> {
                         false,
                         false,
                         self.interner,
+                        self.mc.0,
                         self.in_with,
                         self.spanned_source_text.clone_only_source(),
                         self.source_path.clone(),
@@ -492,10 +489,7 @@ impl ByteCompiler<'_> {
 
                     field_compiler.code_block_flags |= CodeBlockFlags::IN_CLASS_FIELD_INITIALIZER;
 
-                    let code = Gc::new(
-                        &unsafe { boa_gc::MutationContext::global() },
-                        field_compiler.finish(),
-                    );
+                    let code = Gc::new(self.mc.0, field_compiler.finish());
                     let index = self.push_function_to_constants(code);
                     let dst = self.register_allocator.alloc();
                     self.emit_get_function(&dst, index);
@@ -526,6 +520,7 @@ impl ByteCompiler<'_> {
                         false,
                         false,
                         self.interner,
+                        self.mc.0,
                         self.in_with,
                         self.spanned_source_text.clone_only_source(),
                         self.source_path.clone(),
@@ -551,7 +546,7 @@ impl ByteCompiler<'_> {
                     field_compiler.code_block_flags |= CodeBlockFlags::IN_CLASS_FIELD_INITIALIZER;
 
                     let code = field_compiler.finish();
-                    let code = Gc::new(&unsafe { boa_gc::MutationContext::global() }, code);
+                    let code = Gc::new(self.mc.0, code);
 
                     static_elements.push(StaticElement::StaticField {
                         code,
@@ -570,6 +565,7 @@ impl ByteCompiler<'_> {
                         false,
                         false,
                         self.interner,
+                        self.mc.0,
                         self.in_with,
                         self.spanned_source_text.clone_only_source(),
                         self.source_path.clone(),
@@ -595,7 +591,7 @@ impl ByteCompiler<'_> {
                     field_compiler.code_block_flags |= CodeBlockFlags::IN_CLASS_FIELD_INITIALIZER;
 
                     let code = field_compiler.finish();
-                    let code = Gc::new(&unsafe { boa_gc::MutationContext::global() }, code);
+                    let code = Gc::new(self.mc.0, code);
 
                     static_elements.push(StaticElement::StaticField {
                         code,
@@ -613,6 +609,7 @@ impl ByteCompiler<'_> {
                         false,
                         false,
                         self.interner,
+                        self.mc.0,
                         self.in_with,
                         self.spanned_source_text.clone_only_source(),
                         self.source_path.clone(),
@@ -638,10 +635,7 @@ impl ByteCompiler<'_> {
                         );
                     }
 
-                    let code = Gc::new(
-                        &unsafe { boa_gc::MutationContext::global() },
-                        compiler.finish(),
-                    );
+                    let code = Gc::new(self.mc.0, compiler.finish());
                     static_elements.push(StaticElement::StaticBlock(code));
                 }
             }
diff --git a/core/engine/src/bytecompiler/declarations.rs b/core/engine/src/bytecompiler/declarations.rs
index d44a2691fc3..eefc186c143 100644
--- a/core/engine/src/bytecompiler/declarations.rs
+++ b/core/engine/src/bytecompiler/declarations.rs
@@ -539,6 +539,7 @@ impl ByteCompiler<'_> {
                     &scopes,
                     contains_direct_eval,
                     self.interner,
+                    self.mc.0,
                 );
 
             // Ensures global functions are printed when generating the global flowgraph.
@@ -817,6 +818,7 @@ impl ByteCompiler<'_> {
                     &scopes,
                     contains_direct_eval,
                     self.interner,
+                    self.mc.0,
                 );
 
             // b. Let fo be InstantiateFunctionObject of f with arguments lexEnv and privateEnv.
diff --git a/core/engine/src/bytecompiler/function.rs b/core/engine/src/bytecompiler/function.rs
index d1633a34cd6..371b8ab53fc 100644
--- a/core/engine/src/bytecompiler/function.rs
+++ b/core/engine/src/bytecompiler/function.rs
@@ -122,6 +122,7 @@ impl FunctionCompiler {
         scopes: &FunctionScopes,
         contains_direct_eval: bool,
         interner: &mut Interner,
+        mc: &boa_gc::MutationContext<'static, 'static>,
     ) -> Gc<'static, CodeBlock> {
         self.strict = self.strict || body.strict();
 
@@ -136,6 +137,7 @@ impl FunctionCompiler {
             self.r#async,
             self.generator,
             interner,
+            mc,
             self.in_with,
             self.spanned_source_text,
             self.source_path,
@@ -227,6 +229,6 @@ impl FunctionCompiler {
 
         let code = compiler.finish();
 
-        Gc::new(&unsafe { boa_gc::MutationContext::global() }, code)
+        Gc::new(mc, code)
     }
 }
diff --git a/core/engine/src/bytecompiler/mod.rs b/core/engine/src/bytecompiler/mod.rs
index 839b40c98fc..e6dcd761d16 100644
--- a/core/engine/src/bytecompiler/mod.rs
+++ b/core/engine/src/bytecompiler/mod.rs
@@ -489,6 +489,15 @@ impl<'a> BorrowMut<ByteCompiler<'a>> for SourcePositionGuard<'_, 'a> {
     }
 }
 
+#[derive(Clone, Copy)]
+pub(crate) struct McWrapper<'ctx>(pub(crate) &'ctx boa_gc::MutationContext<'static, 'static>);
+
+impl<'ctx> std::fmt::Debug for McWrapper<'ctx> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_tuple("MutationContext").finish()
+    }
+}
+
 /// The [`ByteCompiler`] is used to compile ECMAScript AST from [`boa_ast`] to bytecode.
 #[derive(Debug)]
 #[allow(clippy::struct_excessive_bools)]
@@ -556,6 +565,8 @@ pub struct ByteCompiler<'ctx> {
     pub(crate) emitted_mapped_arguments_object_opcode: bool,
 
     pub(crate) interner: &'ctx mut Interner,
+    /// The MutationContext for GC allocations.
+    pub(crate) mc: McWrapper<'ctx>,
     spanned_source_text: SpannedSourceText,
 
     pub(crate) global_lexs: Vec<u32>,
@@ -603,6 +614,7 @@ impl<'ctx> ByteCompiler<'ctx> {
         is_async: bool,
         is_generator: bool,
         interner: &'ctx mut Interner,
+        mc: &'ctx boa_gc::MutationContext<'static, 'static>,
         in_with: bool,
         spanned_source_text: SpannedSourceText,
         source_path: SourcePath,
@@ -674,6 +686,7 @@ impl<'ctx> ByteCompiler<'ctx> {
             variable_scope,
             lexical_scope,
             interner,
+            mc: McWrapper(mc),
             spanned_source_text,
             source_path,
 
@@ -2441,6 +2454,7 @@ impl<'ctx> ByteCompiler<'ctx> {
                 scopes,
                 function.contains_direct_eval,
                 self.interner,
+                self.mc.0,
             );
 
         self.push_function_to_constants(code)
@@ -2522,6 +2536,7 @@ impl<'ctx> ByteCompiler<'ctx> {
                 scopes,
                 function.contains_direct_eval,
                 self.interner,
+                self.mc.0,
             );
 
         let index = self.push_function_to_constants(code);
@@ -2572,6 +2587,7 @@ impl<'ctx> ByteCompiler<'ctx> {
                 scopes,
                 function.contains_direct_eval,
                 self.interner,
+                self.mc.0,
             );
 
         let index = self.push_function_to_constants(code);
diff --git a/core/engine/src/context/intrinsics.rs b/core/engine/src/context/intrinsics.rs
index 98e601c9d4f..edd57db8cdf 100644
--- a/core/engine/src/context/intrinsics.rs
+++ b/core/engine/src/context/intrinsics.rs
@@ -39,13 +39,16 @@ impl Intrinsics {
     /// To initialize all the intrinsics with their spec properties, see [`Realm::initialize`].
     ///
     /// [`Realm::initialize`]: crate::realm::Realm::initialize
-    pub(crate) fn uninit(root_shape: &RootShape) -> Option<Self> {
-        let constructors = StandardConstructors::default();
-        let templates = ObjectTemplates::new(root_shape, &constructors);
+    pub(crate) fn uninit(
+        root_shape: &RootShape,
+        mc: &boa_gc::MutationContext<'static, '_>,
+    ) -> Option<Self> {
+        let constructors = StandardConstructors::uninit(mc);
+        let templates = ObjectTemplates::new(mc, root_shape, &constructors);
 
         Some(Self {
             constructors,
-            objects: IntrinsicObjects::uninit()?,
+            objects: IntrinsicObjects::uninit(mc)?,
             templates,
         })
     }
@@ -78,14 +81,18 @@ pub struct StandardConstructor {
 
 impl Default for StandardConstructor {
     fn default() -> Self {
-        Self {
-            constructor: JsFunction::empty_intrinsic_function(true),
-            prototype: JsObject::with_null_proto(),
-        }
+        Self::uninit(&unsafe { boa_gc::MutationContext::global() })
     }
 }
 
 impl StandardConstructor {
+    /// Creates a new uninitialized `StandardConstructor` using the given context.
+    pub(crate) fn uninit(mc: &boa_gc::MutationContext<'static, '_>) -> Self {
+        Self {
+            constructor: JsFunction::empty_intrinsic_function_in(mc, true),
+            prototype: JsObject::with_null_proto_in(mc),
+        }
+    }
     /// Creates a new `StandardConstructor` from the constructor and the prototype.
     pub(crate) fn new(constructor: JsFunction, prototype: JsObject) -> Self {
         Self {
@@ -94,14 +101,19 @@ impl StandardConstructor {
         }
     }
 
-    /// Build a constructor with a defined prototype.
-    fn with_prototype(prototype: JsObject) -> Self {
+    /// Build a constructor with a defined prototype, using the given context.
+    fn with_prototype_in(mc: &boa_gc::MutationContext<'static, '_>, prototype: JsObject) -> Self {
         Self {
-            constructor: JsFunction::empty_intrinsic_function(true),
+            constructor: JsFunction::empty_intrinsic_function_in(mc, true),
             prototype,
         }
     }
 
+    /// Build a constructor with a defined prototype.
+    fn with_prototype(prototype: JsObject) -> Self {
+        Self::with_prototype_in(&unsafe { boa_gc::MutationContext::global() }, prototype)
+    }
+
     /// Return the prototype of the constructor object.
     ///
     /// This is the same as `Object.prototype`, `Array.prototype`, etc.
@@ -206,100 +218,111 @@ pub struct StandardConstructors {
     calendar: StandardConstructor,
 }
 
-impl Default for StandardConstructors {
-    fn default() -> Self {
+impl StandardConstructors {
+    pub(crate) fn uninit(mc: &boa_gc::MutationContext<'static, '_>) -> Self {
         Self {
-            object: StandardConstructor::with_prototype(JsObject::from_object_and_vtable(
-                Object::<OrdinaryObject>::default(),
-                &IMMUTABLE_PROTOTYPE_EXOTIC_INTERNAL_METHODS,
-            )),
-            async_generator_function: StandardConstructor::default(),
-            proxy: StandardConstructor::default(),
-            date: StandardConstructor::default(),
+            object: StandardConstructor::with_prototype_in(
+                mc,
+                JsObject::from_object_and_vtable_in(
+                    mc,
+                    Object::<OrdinaryObject>::default(),
+                    &IMMUTABLE_PROTOTYPE_EXOTIC_INTERNAL_METHODS,
+                ),
+            ),
+            async_generator_function: StandardConstructor::uninit(mc),
+            proxy: StandardConstructor::uninit(mc),
+            date: StandardConstructor::uninit(mc),
             function: StandardConstructor {
-                constructor: JsFunction::empty_intrinsic_function(true),
-                prototype: JsFunction::empty_intrinsic_function(false).into(),
+                constructor: JsFunction::empty_intrinsic_function_in(mc, true),
+                prototype: JsFunction::empty_intrinsic_function_in(mc, false).into(),
             },
-            async_function: StandardConstructor::default(),
-            generator_function: StandardConstructor::default(),
-            array: StandardConstructor::with_prototype(JsObject::from_proto_and_data(None, Array)),
-            bigint: StandardConstructor::default(),
-            number: StandardConstructor::with_prototype(JsObject::from_proto_and_data(None, 0.0)),
-            boolean: StandardConstructor::with_prototype(JsObject::from_proto_and_data(
-                None, false,
-            )),
-            string: StandardConstructor::with_prototype(JsObject::from_proto_and_data(
-                None,
-                js_string!(),
-            )),
-            regexp: StandardConstructor::default(),
-            symbol: StandardConstructor::default(),
-            error: StandardConstructor::default(),
-            type_error: StandardConstructor::default(),
-            reference_error: StandardConstructor::default(),
-            range_error: StandardConstructor::default(),
-            syntax_error: StandardConstructor::default(),
-            eval_error: StandardConstructor::default(),
-            uri_error: StandardConstructor::default(),
-            aggregate_error: StandardConstructor::default(),
-            map: StandardConstructor::default(),
-            set: StandardConstructor::default(),
-            typed_array: StandardConstructor::default(),
-            typed_int8_array: StandardConstructor::default(),
-            typed_uint8_array: StandardConstructor::default(),
-            typed_uint8clamped_array: StandardConstructor::default(),
-            typed_int16_array: StandardConstructor::default(),
-            typed_uint16_array: StandardConstructor::default(),
-            typed_int32_array: StandardConstructor::default(),
-            typed_uint32_array: StandardConstructor::default(),
-            typed_bigint64_array: StandardConstructor::default(),
-            typed_biguint64_array: StandardConstructor::default(),
+            async_function: StandardConstructor::uninit(mc),
+            generator_function: StandardConstructor::uninit(mc),
+            array: StandardConstructor::with_prototype_in(
+                mc,
+                JsObject::from_proto_and_data_in(mc, None, Array),
+            ),
+            bigint: StandardConstructor::uninit(mc),
+            number: StandardConstructor::with_prototype_in(
+                mc,
+                JsObject::from_proto_and_data_in(mc, None, 0.0),
+            ),
+            boolean: StandardConstructor::with_prototype_in(
+                mc,
+                JsObject::from_proto_and_data_in(mc, None, false),
+            ),
+            string: StandardConstructor::with_prototype_in(
+                mc,
+                JsObject::from_proto_and_data_in(mc, None, js_string!()),
+            ),
+            regexp: StandardConstructor::uninit(mc),
+            symbol: StandardConstructor::uninit(mc),
+            error: StandardConstructor::uninit(mc),
+            type_error: StandardConstructor::uninit(mc),
+            reference_error: StandardConstructor::uninit(mc),
+            range_error: StandardConstructor::uninit(mc),
+            syntax_error: StandardConstructor::uninit(mc),
+            eval_error: StandardConstructor::uninit(mc),
+            uri_error: StandardConstructor::uninit(mc),
+            aggregate_error: StandardConstructor::uninit(mc),
+            map: StandardConstructor::uninit(mc),
+            set: StandardConstructor::uninit(mc),
+            typed_array: StandardConstructor::uninit(mc),
+            typed_int8_array: StandardConstructor::uninit(mc),
+            typed_uint8_array: StandardConstructor::uninit(mc),
+            typed_uint8clamped_array: StandardConstructor::uninit(mc),
+            typed_int16_array: StandardConstructor::uninit(mc),
+            typed_uint16_array: StandardConstructor::uninit(mc),
+            typed_int32_array: StandardConstructor::uninit(mc),
+            typed_uint32_array: StandardConstructor::uninit(mc),
+            typed_bigint64_array: StandardConstructor::uninit(mc),
+            typed_biguint64_array: StandardConstructor::uninit(mc),
             #[cfg(feature = "float16")]
-            typed_float16_array: StandardConstructor::default(),
-            typed_float32_array: StandardConstructor::default(),
-            typed_float64_array: StandardConstructor::default(),
-            array_buffer: StandardConstructor::default(),
-            shared_array_buffer: StandardConstructor::default(),
-            data_view: StandardConstructor::default(),
-            date_time_format: StandardConstructor::default(),
-            promise: StandardConstructor::default(),
-            weak_ref: StandardConstructor::default(),
-            weak_map: StandardConstructor::default(),
-            weak_set: StandardConstructor::default(),
-            iterator: StandardConstructor::default(),
-            finalization_registry: StandardConstructor::default(),
+            typed_float16_array: StandardConstructor::uninit(mc),
+            typed_float32_array: StandardConstructor::uninit(mc),
+            typed_float64_array: StandardConstructor::uninit(mc),
+            array_buffer: StandardConstructor::uninit(mc),
+            shared_array_buffer: StandardConstructor::uninit(mc),
+            data_view: StandardConstructor::uninit(mc),
+            date_time_format: StandardConstructor::uninit(mc),
+            promise: StandardConstructor::uninit(mc),
+            weak_ref: StandardConstructor::uninit(mc),
+            weak_map: StandardConstructor::uninit(mc),
+            weak_set: StandardConstructor::uninit(mc),
+            iterator: StandardConstructor::uninit(mc),
+            finalization_registry: StandardConstructor::uninit(mc),
             #[cfg(feature = "intl")]
-            collator: StandardConstructor::default(),
+            collator: StandardConstructor::uninit(mc),
             #[cfg(feature = "intl")]
-            list_format: StandardConstructor::default(),
+            list_format: StandardConstructor::uninit(mc),
             #[cfg(feature = "intl")]
-            locale: StandardConstructor::default(),
+            locale: StandardConstructor::uninit(mc),
             #[cfg(feature = "intl")]
-            segmenter: StandardConstructor::default(),
+            segmenter: StandardConstructor::uninit(mc),
             #[cfg(feature = "intl")]
-            plural_rules: StandardConstructor::default(),
+            plural_rules: StandardConstructor::uninit(mc),
             #[cfg(feature = "intl")]
-            number_format: StandardConstructor::default(),
+            number_format: StandardConstructor::uninit(mc),
             #[cfg(feature = "temporal")]
-            instant: StandardConstructor::default(),
+            instant: StandardConstructor::uninit(mc),
             #[cfg(feature = "temporal")]
-            plain_date_time: StandardConstructor::default(),
+            plain_date_time: StandardConstructor::uninit(mc),
             #[cfg(feature = "temporal")]
-            plain_date: StandardConstructor::default(),
+            plain_date: StandardConstructor::uninit(mc),
             #[cfg(feature = "temporal")]
-            plain_time: StandardConstructor::default(),
+            plain_time: StandardConstructor::uninit(mc),
             #[cfg(feature = "temporal")]
-            plain_year_month: StandardConstructor::default(),
+            plain_year_month: StandardConstructor::uninit(mc),
             #[cfg(feature = "temporal")]
-            plain_month_day: StandardConstructor::default(),
+            plain_month_day: StandardConstructor::uninit(mc),
             #[cfg(feature = "temporal")]
-            time_zone: StandardConstructor::default(),
+            time_zone: StandardConstructor::uninit(mc),
             #[cfg(feature = "temporal")]
-            duration: StandardConstructor::default(),
+            duration: StandardConstructor::uninit(mc),
             #[cfg(feature = "temporal")]
-            zoned_date_time: StandardConstructor::default(),
+            zoned_date_time: StandardConstructor::uninit(mc),
             #[cfg(feature = "temporal")]
-            calendar: StandardConstructor::default(),
+            calendar: StandardConstructor::uninit(mc),
         }
     }
 }
@@ -1164,28 +1187,28 @@ impl IntrinsicObjects {
     ///
     /// [`Realm::initialize`]: crate::realm::Realm::initialize
     #[allow(clippy::unnecessary_wraps)]
-    pub(crate) fn uninit() -> Option<Self> {
+    pub(crate) fn uninit(mc: &boa_gc::MutationContext<'static, '_>) -> Option<Self> {
         Some(Self {
-            reflect: JsObject::with_null_proto(),
-            math: JsObject::with_null_proto(),
-            json: JsObject::with_null_proto(),
-            throw_type_error: JsFunction::empty_intrinsic_function(false),
-            array_prototype_values: JsFunction::empty_intrinsic_function(false),
-            array_prototype_to_string: JsFunction::empty_intrinsic_function(false),
-            iterator_prototypes: IteratorPrototypes::default(),
-            generator: JsObject::with_null_proto(),
-            async_generator: JsObject::with_null_proto(),
-            atomics: JsObject::with_null_proto(),
-            eval: JsFunction::empty_intrinsic_function(false),
-            uri_functions: UriFunctions::default(),
-            is_finite: JsFunction::empty_intrinsic_function(false),
-            is_nan: JsFunction::empty_intrinsic_function(false),
-            parse_float: JsFunction::empty_intrinsic_function(false),
-            parse_int: JsFunction::empty_intrinsic_function(false),
+            reflect: JsObject::with_null_proto_in(mc),
+            math: JsObject::with_null_proto_in(mc),
+            json: JsObject::with_null_proto_in(mc),
+            throw_type_error: JsFunction::empty_intrinsic_function_in(mc, false),
+            array_prototype_values: JsFunction::empty_intrinsic_function_in(mc, false),
+            array_prototype_to_string: JsFunction::empty_intrinsic_function_in(mc, false),
+            iterator_prototypes: IteratorPrototypes::uninit_in(mc),
+            generator: JsObject::with_null_proto_in(mc),
+            async_generator: JsObject::with_null_proto_in(mc),
+            atomics: JsObject::with_null_proto_in(mc),
+            eval: JsFunction::empty_intrinsic_function_in(mc, false),
+            uri_functions: UriFunctions::uninit_in(mc),
+            is_finite: JsFunction::empty_intrinsic_function_in(mc, false),
+            is_nan: JsFunction::empty_intrinsic_function_in(mc, false),
+            parse_float: JsFunction::empty_intrinsic_function_in(mc, false),
+            parse_int: JsFunction::empty_intrinsic_function_in(mc, false),
             #[cfg(feature = "annex-b")]
-            escape: JsFunction::empty_intrinsic_function(false),
+            escape: JsFunction::empty_intrinsic_function_in(mc, false),
             #[cfg(feature = "annex-b")]
-            unescape: JsFunction::empty_intrinsic_function(false),
+            unescape: JsFunction::empty_intrinsic_function_in(mc, false),
             #[cfg(feature = "intl")]
             intl: JsObject::new_unique(None, Intl::new()?),
             #[cfg(feature = "intl")]
@@ -1434,45 +1457,56 @@ pub(crate) struct ObjectTemplates {
 }
 
 impl ObjectTemplates {
-    pub(crate) fn new(root_shape: &RootShape, constructors: &StandardConstructors) -> Self {
+    pub(crate) fn new(
+        mc: &boa_gc::MutationContext<'static, '_>,
+        root_shape: &RootShape,
+        constructors: &StandardConstructors,
+    ) -> Self {
         let root_shape = root_shape.shape();
 
         // pre-initialize used shapes.
         let ordinary_object =
-            ObjectTemplate::with_prototype(root_shape, constructors.object().prototype());
+            ObjectTemplate::with_prototype_in(mc, root_shape, constructors.object().prototype());
         let mut array = ObjectTemplate::new(root_shape);
         let length_property_key: PropertyKey = js_string!("length").into();
-        array.property(
+        array.property_in(
+            mc,
             length_property_key.clone(),
             Attribute::WRITABLE | Attribute::PERMANENT | Attribute::NON_ENUMERABLE,
         );
-        array.set_prototype(constructors.array().prototype());
-
-        let number = ObjectTemplate::with_prototype(root_shape, constructors.number().prototype());
-        let symbol = ObjectTemplate::with_prototype(root_shape, constructors.symbol().prototype());
-        let bigint = ObjectTemplate::with_prototype(root_shape, constructors.bigint().prototype());
+        array.set_prototype_in(mc, constructors.array().prototype());
+
+        let number =
+            ObjectTemplate::with_prototype_in(mc, root_shape, constructors.number().prototype());
+        let symbol =
+            ObjectTemplate::with_prototype_in(mc, root_shape, constructors.symbol().prototype());
+        let bigint =
+            ObjectTemplate::with_prototype_in(mc, root_shape, constructors.bigint().prototype());
         let boolean =
-            ObjectTemplate::with_prototype(root_shape, constructors.boolean().prototype());
+            ObjectTemplate::with_prototype_in(mc, root_shape, constructors.boolean().prototype());
         let mut string = ObjectTemplate::new(root_shape);
-        string.property(
+        string.property_in(
+            mc,
             length_property_key.clone(),
             Attribute::READONLY | Attribute::PERMANENT | Attribute::NON_ENUMERABLE,
         );
-        string.set_prototype(constructors.string().prototype());
+        string.set_prototype_in(mc, constructors.string().prototype());
 
         let mut regexp_without_proto = ObjectTemplate::new(root_shape);
-        regexp_without_proto.property(js_string!("lastIndex").into(), Attribute::WRITABLE);
+        regexp_without_proto.property_in(mc, js_string!("lastIndex").into(), Attribute::WRITABLE);
 
         let mut regexp = regexp_without_proto.clone();
-        regexp.set_prototype(constructors.regexp().prototype());
+        regexp.set_prototype_in(mc, constructors.regexp().prototype());
 
         let name_property_key: PropertyKey = js_string!("name").into();
         let mut function = ObjectTemplate::new(root_shape);
-        function.property(
+        function.property_in(
+            mc,
             length_property_key.clone(),
             Attribute::READONLY | Attribute::CONFIGURABLE | Attribute::NON_ENUMERABLE,
         );
-        function.property(
+        function.property_in(
+            mc,
             name_property_key,
             Attribute::READONLY | Attribute::CONFIGURABLE | Attribute::NON_ENUMERABLE,
         );
@@ -1481,7 +1515,8 @@ impl ObjectTemplates {
         let mut async_function = function.clone();
         let mut function_with_prototype = function.clone();
 
-        function_with_prototype.property(
+        function_with_prototype.property_in(
+            mc,
             PROTOTYPE.into(),
             Attribute::WRITABLE | Attribute::PERMANENT | Attribute::NON_ENUMERABLE,
         );
@@ -1490,14 +1525,16 @@ impl ObjectTemplates {
 
         let function_with_prototype_without_proto = function_with_prototype.clone();
 
-        function.set_prototype(constructors.function().prototype());
-        function_with_prototype.set_prototype(constructors.function().prototype());
-        async_function.set_prototype(constructors.async_function().prototype());
-        generator_function.set_prototype(constructors.generator_function().prototype());
-        async_generator_function.set_prototype(constructors.async_generator_function().prototype());
+        function.set_prototype_in(mc, constructors.function().prototype());
+        function_with_prototype.set_prototype_in(mc, constructors.function().prototype());
+        async_function.set_prototype_in(mc, constructors.async_function().prototype());
+        generator_function.set_prototype_in(mc, constructors.generator_function().prototype());
+        async_generator_function
+            .set_prototype_in(mc, constructors.async_generator_function().prototype());
 
         let mut function_prototype = ordinary_object.clone();
-        function_prototype.property(
+        function_prototype.property_in(
+            mc,
             CONSTRUCTOR.into(),
             Attribute::WRITABLE | Attribute::CONFIGURABLE | Attribute::NON_ENUMERABLE,
         );
@@ -1506,7 +1543,8 @@ impl ObjectTemplates {
 
         // 4. Perform DefinePropertyOrThrow(obj, "length", PropertyDescriptor { [[Value]]: 𝔽(len),
         // [[Writable]]: true, [[Enumerable]]: false, [[Configurable]]: true }).
-        unmapped_arguments.property(
+        unmapped_arguments.property_in(
+            mc,
             length_property_key,
             Attribute::WRITABLE | Attribute::NON_ENUMERABLE | Attribute::CONFIGURABLE,
         );
@@ -1514,7 +1552,8 @@ impl ObjectTemplates {
         // 7. Perform ! DefinePropertyOrThrow(obj, @@iterator, PropertyDescriptor {
         // [[Value]]: %Array.prototype.values%, [[Writable]]: true, [[Enumerable]]: false,
         // [[Configurable]]: true }).
-        unmapped_arguments.property(
+        unmapped_arguments.property_in(
+            mc,
             JsSymbol::iterator().into(),
             Attribute::WRITABLE | Attribute::NON_ENUMERABLE | Attribute::CONFIGURABLE,
         );
@@ -1524,7 +1563,8 @@ impl ObjectTemplates {
         // 8. Perform ! DefinePropertyOrThrow(obj, "callee", PropertyDescriptor {
         // [[Get]]: %ThrowTypeError%, [[Set]]: %ThrowTypeError%, [[Enumerable]]: false,
         // [[Configurable]]: false }).
-        unmapped_arguments.accessor(
+        unmapped_arguments.accessor_in(
+            mc,
             js_string!("callee").into(),
             true,
             true,
@@ -1533,34 +1573,37 @@ impl ObjectTemplates {
 
         // 21. Perform ! DefinePropertyOrThrow(obj, "callee", PropertyDescriptor {
         // [[Value]]: func, [[Writable]]: true, [[Enumerable]]: false, [[Configurable]]: true }).
-        mapped_arguments.property(
+        mapped_arguments.property_in(
+            mc,
             js_string!("callee").into(),
             Attribute::WRITABLE | Attribute::NON_ENUMERABLE | Attribute::CONFIGURABLE,
         );
 
         let mut iterator_result = ordinary_object.clone();
-        iterator_result.property(
+        iterator_result.property_in(
+            mc,
             js_string!("value").into(),
             Attribute::WRITABLE | Attribute::CONFIGURABLE | Attribute::ENUMERABLE,
         );
-        iterator_result.property(
+        iterator_result.property_in(
+            mc,
             js_string!("done").into(),
             Attribute::WRITABLE | Attribute::CONFIGURABLE | Attribute::ENUMERABLE,
         );
 
         let mut namespace = ObjectTemplate::new(root_shape);
-        namespace.property(JsSymbol::to_string_tag().into(), Attribute::empty());
+        namespace.property_in(mc, JsSymbol::to_string_tag().into(), Attribute::empty());
 
         let with_resolvers = {
             let mut with_resolvers = ordinary_object.clone();
 
             with_resolvers
                 // 4. Perform ! CreateDataPropertyOrThrow(obj, "promise", promiseCapability.[[Promise]]).
-                .property(js_string!("promise").into(), Attribute::all())
+                .property_in(mc, js_string!("promise").into(), Attribute::all())
                 // 5. Perform ! CreateDataPropertyOrThrow(obj, "resolve", promiseCapability.[[Resolve]]).
-                .property(js_string!("resolve").into(), Attribute::all())
+                .property_in(mc, js_string!("resolve").into(), Attribute::all())
                 // 6. Perform ! CreateDataPropertyOrThrow(obj, "reject", promiseCapability.[[Reject]]).
-                .property(js_string!("reject").into(), Attribute::all());
+                .property_in(mc, js_string!("reject").into(), Attribute::all());
 
             with_resolvers
         };
@@ -1568,8 +1611,8 @@ impl ObjectTemplates {
         let wait_async = {
             let mut obj = ordinary_object.clone();
 
-            obj.property(js_string!("async").into(), Attribute::all())
-                .property(js_string!("value").into(), Attribute::all());
+            obj.property_in(mc, js_string!("async").into(), Attribute::all())
+                .property_in(mc, js_string!("value").into(), Attribute::all());
 
             obj
         };
diff --git a/core/engine/src/context/mod.rs b/core/engine/src/context/mod.rs
index bd0aa5783db..218d177ffda 100644
--- a/core/engine/src/context/mod.rs
+++ b/core/engine/src/context/mod.rs
@@ -474,10 +474,9 @@ impl Context {
         self.gc.alloc(value)
     }
 
-    /// Returns the active collector.
-    #[inline]
+    /// Gets the GC collector.
     #[must_use]
-    pub fn gc_collector(&self) -> &boa_gc::MutationContext<'static, 'static> {
+    pub fn gc_collector(&self) -> &'static boa_gc::MutationContext<'static, 'static> {
         self.gc.gc_collector()
     }
 
@@ -549,7 +548,9 @@ impl Context {
 
     /// Create a new Realm with the default global bindings.
     pub fn create_realm(&mut self) -> JsResult<Realm> {
-        let realm = Realm::create(self.host_hooks.as_ref(), &self.root_shape)?;
+        let realm = Realm::create(self.host_hooks.as_ref(), &self.root_shape, &unsafe {
+            boa_gc::MutationContext::global()
+        })?;
 
         let old_realm = self.enter_realm(realm);
 
@@ -1223,12 +1224,13 @@ impl ContextBuilder {
             CANNOT_BLOCK_COUNTER.set(CANNOT_BLOCK_COUNTER.get() + 1);
         }
 
-        let root_shape = RootShape::default();
+        let mc = unsafe { boa_gc::MutationContext::global() };
+        let root_shape = RootShape::new_in(&mc);
 
         let host_hooks = self.host_hooks.unwrap_or(Rc::new(DefaultHooks));
         let clock = self.clock.unwrap_or_else(|| Rc::new(StdClock::new()));
-        let realm = Realm::create(host_hooks.as_ref(), &root_shape)?;
-        let vm = Vm::new(realm);
+        let realm = Realm::create(host_hooks.as_ref(), &root_shape, &mc)?;
+        let vm = Vm::new(realm, &mc);
 
         let module_loader: Rc<dyn DynModuleLoader> = if let Some(loader) = self.module_loader {
             loader
diff --git a/core/engine/src/environments/runtime/mod.rs b/core/engine/src/environments/runtime/mod.rs
index 59724b87c38..4e47a4f79ff 100644
--- a/core/engine/src/environments/runtime/mod.rs
+++ b/core/engine/src/environments/runtime/mod.rs
@@ -216,7 +216,7 @@ impl EnvironmentStack {
         &mut self,
         bindings_count: u32,
         global: &Gc<'static, DeclarativeEnvironment>,
-        gc: boa_gc::MutationContext<'static, '_>,
+        gc: &boa_gc::MutationContext<'static, '_>,
     ) -> u32 {
         let (poisoned, with) = self.compute_poisoned_with(global);
 
@@ -240,14 +240,14 @@ impl EnvironmentStack {
         scope: Scope,
         function_slots: FunctionSlots,
         global: &Gc<'static, DeclarativeEnvironment>,
-        gc: boa_gc::MutationContext<'static, '_>,
+        gc: &boa_gc::MutationContext<'static, '_>,
     ) {
         let num_bindings = scope.num_bindings_non_local();
 
         let (poisoned, with) = self.compute_poisoned_with(global);
 
         self.push_env(Environment::Declarative(Gc::new(
-            &gc,
+            gc,
             DeclarativeEnvironment::new(
                 DeclarativeEnvironmentKind::Function(FunctionEnvironment::new(
                     num_bindings,
@@ -261,10 +261,10 @@ impl EnvironmentStack {
     }
 
     /// Push a module environment on the environments stack.
-    pub(crate) fn push_module(&mut self, scope: Scope, gc: boa_gc::MutationContext<'static, '_>) {
+    pub(crate) fn push_module(&mut self, scope: Scope, gc: &boa_gc::MutationContext<'static, '_>) {
         let num_bindings = scope.num_bindings_non_local();
         self.push_env(Environment::Declarative(Gc::new(
-            &gc,
+            gc,
             DeclarativeEnvironment::new(
                 DeclarativeEnvironmentKind::Module(ModuleEnvironment::new(num_bindings, scope)),
                 false,
diff --git a/core/engine/src/module/source.rs b/core/engine/src/module/source.rs
index 2f32a2d2cb3..c7962cc5b32 100644
--- a/core/engine/src/module/source.rs
+++ b/core/engine/src/module/source.rs
@@ -1645,6 +1645,7 @@ impl SourceTextModule {
         let env = source.scope().clone();
 
         let spanned_source_text = SpannedSourceText::new_source_only(source_text.clone());
+        let mc = context.gc_collector();
         let mut compiler = ByteCompiler::new(
             js_string!("<main>"),
             true,
@@ -1654,6 +1655,7 @@ impl SourceTextModule {
             self.code.has_tla,
             false,
             context.interner_mut(),
+            &mc,
             false,
             spanned_source_text,
             self.code.path.clone().into(),
@@ -1834,7 +1836,7 @@ impl SourceTextModule {
 
         // 8. Let moduleContext be a new ECMAScript code execution context.
         let mut envs = EnvironmentStack::new();
-        envs.push_module(source.scope().clone(), unsafe {
+        envs.push_module(source.scope().clone(), &unsafe {
             boa_gc::MutationContext::global()
         });
         drop(status);
diff --git a/core/engine/src/module/synthetic.rs b/core/engine/src/module/synthetic.rs
index 888c0db39cf..f0bbde545fa 100644
--- a/core/engine/src/module/synthetic.rs
+++ b/core/engine/src/module/synthetic.rs
@@ -311,6 +311,7 @@ impl SyntheticModule {
 
         // TODO: A bit of a hack to be able to pass the currently active runnable without an
         // available codeblock to execute.
+        let mc = context.gc_collector();
         let compiler = ByteCompiler::new(
             js_string!("<synthetic>"),
             true,
@@ -320,6 +321,7 @@ impl SyntheticModule {
             false,
             false,
             context.interner_mut(),
+            &mc,
             false,
             // A synthetic module does not contain `SourceText`
             SpannedSourceText::new_empty(),
@@ -342,7 +344,7 @@ impl SyntheticModule {
         let cb = context.alloc(finished);
 
         let mut envs = EnvironmentStack::new();
-        envs.push_module(module_scope, unsafe { boa_gc::MutationContext::global() });
+        envs.push_module(module_scope, &unsafe { boa_gc::MutationContext::global() });
 
         for locator in exports {
             //     b. Perform ! env.InitializeBinding(exportName, undefined).
diff --git a/core/engine/src/object/builtins/jsfunction.rs b/core/engine/src/object/builtins/jsfunction.rs
index c1bc9d152e8..0d165e0c17c 100644
--- a/core/engine/src/object/builtins/jsfunction.rs
+++ b/core/engine/src/object/builtins/jsfunction.rs
@@ -122,14 +122,14 @@ impl JsFunction {
         Self { inner: object }
     }
 
-    /// Creates a new, empty intrinsic function object with only its function internal methods set.
-    ///
-    /// Mainly used to initialize objects before a [`Context`] is available to do so.
-    ///
-    /// [`Context`]: crate::Context
-    pub(crate) fn empty_intrinsic_function(constructor: bool) -> Self {
+    /// Creates a new, empty intrinsic function object with only its function internal methods set, using the given context.
+    pub(crate) fn empty_intrinsic_function_in(
+        mc: &boa_gc::MutationContext<'static, '_>,
+        constructor: bool,
+    ) -> Self {
         Self {
-            inner: JsObject::from_proto_and_data(
+            inner: JsObject::from_proto_and_data_in(
+                mc,
                 None,
                 NativeFunctionObject {
                     f: NativeFunction::from_fn_ptr(|_, _, _| Ok(JsValue::undefined())),
@@ -141,6 +141,18 @@ impl JsFunction {
         }
     }
 
+    /// Creates a new, empty intrinsic function object with only its function internal methods set.
+    ///
+    /// Mainly used to initialize objects before a [`Context`] is available to do so.
+    ///
+    /// [`Context`]: crate::Context
+    pub(crate) fn empty_intrinsic_function(constructor: bool) -> Self {
+        Self::empty_intrinsic_function_in(
+            &unsafe { boa_gc::MutationContext::global() },
+            constructor,
+        )
+    }
+
     /// Creates a [`JsFunction`] from a [`JsObject`], or returns `None` if the object is not a function.
     ///
     /// This does not clone the fields of the function, it only does a shallow clone of the object.
diff --git a/core/engine/src/object/jsobject.rs b/core/engine/src/object/jsobject.rs
index 711bb3cee2b..10cfd824459 100644
--- a/core/engine/src/object/jsobject.rs
+++ b/core/engine/src/object/jsobject.rs
@@ -116,13 +116,14 @@ impl JsObject {
         Self::with_object_proto(intrinsics)
     }
 
-    /// Creates a new `JsObject` from its inner object and its vtable.
-    pub(crate) fn from_object_and_vtable<T: NativeObject>(
+    /// Creates a new `JsObject` from its inner object and its vtable using the given context.
+    pub(crate) fn from_object_and_vtable_in<T: NativeObject>(
+        mc: &boa_gc::MutationContext<'static, '_>,
         object: Object<T>,
         vtable: &'static InternalObjectMethods,
     ) -> Self {
         let inner = Gc::new(
-            &unsafe { boa_gc::MutationContext::global() },
+            mc,
             VTableObject {
                 object: GcRefCell::new(object),
                 vtable,
@@ -132,6 +133,18 @@ impl JsObject {
         JsObject { inner }.upcast()
     }
 
+    /// Creates a new `JsObject` from its inner object and its vtable.
+    pub(crate) fn from_object_and_vtable<T: NativeObject>(
+        object: Object<T>,
+        vtable: &'static InternalObjectMethods,
+    ) -> Self {
+        Self::from_object_and_vtable_in(
+            &unsafe { boa_gc::MutationContext::global() },
+            object,
+            vtable,
+        )
+    }
+
     /// Creates a new ordinary object with its prototype set to the `Object` prototype.
     ///
     /// This is equivalent to calling the specification's abstract operation
@@ -158,6 +171,13 @@ impl JsObject {
         )
     }
 
+    /// Creates a new ordinary object, with its prototype set to null using the given context.
+    #[inline]
+    #[must_use]
+    pub fn with_null_proto_in(mc: &boa_gc::MutationContext<'static, '_>) -> Self {
+        Self::from_proto_and_data_in(mc, None, OrdinaryObject)
+    }
+
     /// Creates a new ordinary object, with its prototype set to null.
     ///
     /// This is equivalent to calling the specification's abstract operation
@@ -176,7 +196,30 @@ impl JsObject {
     #[inline]
     #[must_use]
     pub fn with_null_proto() -> Self {
-        Self::from_proto_and_data(None, OrdinaryObject)
+        Self::with_null_proto_in(&unsafe { boa_gc::MutationContext::global() })
+    }
+
+    /// Creates a new object with the provided prototype and object data, using the given context.
+    pub fn from_proto_and_data_in<O: Into<Option<Self>>, T: NativeObject>(
+        mc: &boa_gc::MutationContext<'static, '_>,
+        prototype: O,
+        data: T,
+    ) -> Self {
+        let internal_methods = data.internal_methods();
+        let inner = Gc::new(
+            mc,
+            VTableObject {
+                object: GcRefCell::new(Object {
+                    data: ObjectData::new(data),
+                    properties: PropertyMap::from_prototype_unique_shape(prototype.into()),
+                    extensible: true,
+                    private_elements: ThinVec::new(),
+                }),
+                vtable: internal_methods,
+            },
+        );
+
+        JsObject { inner }.upcast()
     }
 
     /// Creates a new object with the provided prototype and object data.
@@ -209,13 +252,33 @@ impl JsObject {
         prototype: O,
         data: T,
     ) -> Self {
+        Self::from_proto_and_data_in(
+            &unsafe { boa_gc::MutationContext::global() },
+            prototype,
+            data,
+        )
+    }
+
+    /// Creates a new object with the provided prototype and object data using the given context.
+    pub(crate) fn from_proto_and_data_with_shared_shape_in<
+        O: Into<Option<Self>>,
+        T: NativeObject,
+    >(
+        mc: &boa_gc::MutationContext<'static, '_>,
+        root_shape: &RootShape,
+        prototype: O,
+        data: T,
+    ) -> JsObject<T> {
         let internal_methods = data.internal_methods();
         let inner = Gc::new(
-            &unsafe { boa_gc::MutationContext::global() },
+            mc,
             VTableObject {
                 object: GcRefCell::new(Object {
                     data: ObjectData::new(data),
-                    properties: PropertyMap::from_prototype_unique_shape(prototype.into()),
+                    properties: PropertyMap::from_prototype_with_shared_shape(
+                        root_shape,
+                        prototype.into(),
+                    ),
                     extensible: true,
                     private_elements: ThinVec::new(),
                 }),
@@ -223,7 +286,7 @@ impl JsObject {
             },
         );
 
-        JsObject { inner }.upcast()
+        JsObject { inner }
     }
 
     /// Creates a new object with the provided prototype and object data.
@@ -238,24 +301,12 @@ impl JsObject {
         prototype: O,
         data: T,
     ) -> JsObject<T> {
-        let internal_methods = data.internal_methods();
-        let inner = Gc::new(
+        Self::from_proto_and_data_with_shared_shape_in(
             &unsafe { boa_gc::MutationContext::global() },
-            VTableObject {
-                object: GcRefCell::new(Object {
-                    data: ObjectData::new(data),
-                    properties: PropertyMap::from_prototype_with_shared_shape(
-                        root_shape,
-                        prototype.into(),
-                    ),
-                    extensible: true,
-                    private_elements: ThinVec::new(),
-                }),
-                vtable: internal_methods,
-            },
-        );
-
-        JsObject { inner }
+            root_shape,
+            prototype,
+            data,
+        )
     }
 
     /// Downcasts the object's inner data if the object is of type `T`.
@@ -1057,6 +1108,33 @@ impl<T: NativeObject> JsObject<T> {
 }
 
 impl<T: NativeObject> JsObject<T> {
+    /// Creates a new `JsObject` from a `RootShape`, prototype, and data using the given context.
+    pub fn new_in<O: Into<Option<JsObject>>>(
+        mc: &boa_gc::MutationContext<'static, '_>,
+        root_shape: &RootShape,
+        prototype: O,
+        data: T,
+    ) -> Self {
+        let internal_methods = data.internal_methods();
+        let inner = Gc::new(
+            mc,
+            VTableObject {
+                object: GcRefCell::new(Object {
+                    data: ObjectData::new(data),
+                    properties: PropertyMap::from_prototype_with_shared_shape(
+                        root_shape,
+                        prototype.into(),
+                    ),
+                    extensible: true,
+                    private_elements: ThinVec::new(),
+                }),
+                vtable: internal_methods,
+            },
+        );
+
+        Self { inner }
+    }
+
     /// Creates a new `JsObject` from its root shape, prototype, and data.
     ///
     /// Note that the returned object will not be erased to be convertible to a
@@ -1080,16 +1158,27 @@ impl<T: NativeObject> JsObject<T> {
     /// assert!(obj.is_ordinary());
     /// ```
     pub fn new<O: Into<Option<JsObject>>>(root_shape: &RootShape, prototype: O, data: T) -> Self {
+        Self::new_in(
+            &unsafe { boa_gc::MutationContext::global() },
+            root_shape,
+            prototype,
+            data,
+        )
+    }
+
+    /// Creates a new `JsObject` from prototype, and data using the given context.
+    pub fn new_unique_in<O: Into<Option<JsObject>>>(
+        mc: &boa_gc::MutationContext<'static, '_>,
+        prototype: O,
+        data: T,
+    ) -> Self {
         let internal_methods = data.internal_methods();
         let inner = Gc::new(
-            &unsafe { boa_gc::MutationContext::global() },
+            mc,
             VTableObject {
                 object: GcRefCell::new(Object {
                     data: ObjectData::new(data),
-                    properties: PropertyMap::from_prototype_with_shared_shape(
-                        root_shape,
-                        prototype.into(),
-                    ),
+                    properties: PropertyMap::from_prototype_unique_shape(prototype.into()),
                     extensible: true,
                     private_elements: ThinVec::new(),
                 }),
@@ -1118,21 +1207,11 @@ impl<T: NativeObject> JsObject<T> {
     /// assert!(obj.prototype().is_none());
     /// ```
     pub fn new_unique<O: Into<Option<JsObject>>>(prototype: O, data: T) -> Self {
-        let internal_methods = data.internal_methods();
-        let inner = Gc::new(
+        Self::new_unique_in(
             &unsafe { boa_gc::MutationContext::global() },
-            VTableObject {
-                object: GcRefCell::new(Object {
-                    data: ObjectData::new(data),
-                    properties: PropertyMap::from_prototype_unique_shape(prototype.into()),
-                    extensible: true,
-                    private_elements: ThinVec::new(),
-                }),
-                vtable: internal_methods,
-            },
-        );
-
-        Self { inner }
+            prototype,
+            data,
+        )
     }
 
     /// Upcasts this object's inner data from a specific type `T` to an erased type
diff --git a/core/engine/src/object/shape/mod.rs b/core/engine/src/object/shape/mod.rs
index bfb7b512183..e4c5889093d 100644
--- a/core/engine/src/object/shape/mod.rs
+++ b/core/engine/src/object/shape/mod.rs
@@ -103,33 +103,45 @@ impl Shape {
         None
     }
 
-    /// Create an insert property transitions returning the new transitioned [`Shape`].
+    /// Create an insert property transitions returning the new transitioned [`Shape`] using the given context.
     ///
     /// NOTE: This assumes that there is no property with the given key!
-    pub(crate) fn insert_property_transition(&self, key: TransitionKey) -> Self {
+    pub(crate) fn insert_property_transition_in(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        key: TransitionKey,
+    ) -> Self {
         match &self.inner {
             Inner::Shared(shape) => {
-                let shape = shape.insert_property_transition(key);
+                let shape = shape.insert_property_transition_in(mc, key);
                 if shape.transition_count() >= Self::TRANSITION_COUNT_MAX {
                     return shape.to_unique().into();
                 }
                 shape.into()
             }
-            Inner::Unique(shape) => shape.insert_property_transition(key).into(),
+            Inner::Unique(shape) => shape.insert_property_transition(key).into(), // UniqueShape insert doesn't allocate new GC
         }
     }
 
+    /// Create an insert property transitions returning the new transitioned [`Shape`].
+    ///
+    /// NOTE: This assumes that there is no property with the given key!
+    pub(crate) fn insert_property_transition(&self, key: TransitionKey) -> Self {
+        self.insert_property_transition_in(&unsafe { boa_gc::MutationContext::global() }, key)
+    }
+
     /// Create a change attribute property transitions returning [`ChangeTransition`] containing the new [`Shape`]
-    /// and actions to be performed
+    /// and actions to be performed, using the given context.
     ///
     /// NOTE: This assumes that there already is a property with the given key!
-    pub(crate) fn change_attributes_transition(
+    pub(crate) fn change_attributes_transition_in(
         &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
         key: TransitionKey,
     ) -> ChangeTransition<Self> {
         match &self.inner {
             Inner::Shared(shape) => {
-                let change_transition = shape.change_attributes_transition(key);
+                let change_transition = shape.change_attributes_transition_in(mc, key);
                 let shape =
                     if change_transition.shape.transition_count() >= Self::TRANSITION_COUNT_MAX {
                         change_transition.shape.to_unique().into()
@@ -145,13 +157,28 @@ impl Shape {
         }
     }
 
-    /// Remove a property property from the [`Shape`] returning the new transitioned [`Shape`].
+    /// Create a change attribute property transitions returning [`ChangeTransition`] containing the new [`Shape`]
+    /// and actions to be performed
     ///
     /// NOTE: This assumes that there already is a property with the given key!
-    pub(crate) fn remove_property_transition(&self, key: &PropertyKey) -> Self {
+    pub(crate) fn change_attributes_transition(
+        &self,
+        key: TransitionKey,
+    ) -> ChangeTransition<Self> {
+        self.change_attributes_transition_in(&unsafe { boa_gc::MutationContext::global() }, key)
+    }
+
+    /// Remove a property from the [`Shape`] returning the new transitioned [`Shape`] using the given context.
+    ///
+    /// NOTE: This assumes that there already is a property with the given key!
+    pub(crate) fn remove_property_transition_in(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        key: &PropertyKey,
+    ) -> Self {
         match &self.inner {
             Inner::Shared(shape) => {
-                let shape = shape.remove_property_transition(key);
+                let shape = shape.remove_property_transition_in(mc, key);
                 if shape.transition_count() >= Self::TRANSITION_COUNT_MAX {
                     return shape.to_unique().into();
                 }
@@ -161,11 +188,22 @@ impl Shape {
         }
     }
 
-    /// Create a prototype transitions returning the new transitioned [`Shape`].
-    pub(crate) fn change_prototype_transition(&self, prototype: JsPrototype) -> Self {
+    /// Remove a property from the [`Shape`] returning the new transitioned [`Shape`].
+    ///
+    /// NOTE: This assumes that there already is a property with the given key!
+    pub(crate) fn remove_property_transition(&self, key: &PropertyKey) -> Self {
+        self.remove_property_transition_in(&unsafe { boa_gc::MutationContext::global() }, key)
+    }
+
+    /// Create a prototype transition returning the new transitioned [`Shape`] using the given context.
+    pub(crate) fn change_prototype_transition_in(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        prototype: JsPrototype,
+    ) -> Self {
         match &self.inner {
             Inner::Shared(shape) => {
-                let shape = shape.change_prototype_transition(prototype);
+                let shape = shape.change_prototype_transition_in(mc, prototype);
                 if shape.transition_count() >= Self::TRANSITION_COUNT_MAX {
                     return shape.to_unique().into();
                 }
@@ -175,6 +213,14 @@ impl Shape {
         }
     }
 
+    /// Create a prototype transition returning the new transitioned [`Shape`].
+    pub(crate) fn change_prototype_transition(&self, prototype: JsPrototype) -> Self {
+        self.change_prototype_transition_in(
+            &unsafe { boa_gc::MutationContext::global() },
+            prototype,
+        )
+    }
+
     /// Get the [`JsPrototype`] of the [`Shape`].
     #[must_use]
     pub fn prototype(&self) -> JsPrototype {
diff --git a/core/engine/src/object/shape/root_shape.rs b/core/engine/src/object/shape/root_shape.rs
index 9cc3de38e59..278bddc6935 100644
--- a/core/engine/src/object/shape/root_shape.rs
+++ b/core/engine/src/object/shape/root_shape.rs
@@ -13,13 +13,18 @@ pub struct RootShape {
 impl Default for RootShape {
     #[inline]
     fn default() -> Self {
-        Self {
-            shape: SharedShape::root(),
-        }
+        Self::new_in(&unsafe { boa_gc::MutationContext::global() })
     }
 }
 
 impl RootShape {
+    /// Create a new root shape using the given context.
+    #[inline]
+    pub(crate) fn new_in(mc: &boa_gc::MutationContext<'static, '_>) -> Self {
+        Self {
+            shape: SharedShape::root_in(mc),
+        }
+    }
     /// Gets the inner [`SharedShape`].
     #[must_use]
     pub const fn shape(&self) -> &SharedShape {
diff --git a/core/engine/src/object/shape/shared_shape/forward_transition.rs b/core/engine/src/object/shape/shared_shape/forward_transition.rs
index 88c286171d3..5846c7916b9 100644
--- a/core/engine/src/object/shape/shared_shape/forward_transition.rs
+++ b/core/engine/src/object/shape/shared_shape/forward_transition.rs
@@ -55,9 +55,10 @@ pub(super) struct ForwardTransition {
 }
 
 impl ForwardTransition {
-    /// Insert a property transition.
-    pub(super) fn insert_property(
+    /// Insert a property transition using the given context.
+    pub(super) fn insert_property_in(
         &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
         key: TransitionKey,
         value: &Gc<'static, SharedShapeInner>,
     ) {
@@ -68,14 +69,25 @@ impl ForwardTransition {
             properties.map.retain(|_, v| v.is_upgradable());
         }
 
-        properties.map.insert(
-            key,
-            WeakGc::new(&unsafe { boa_gc::MutationContext::global() }, value),
-        );
+        properties.map.insert(key, WeakGc::new(mc, value));
     }
 
-    /// Insert a prototype transition.
-    pub(super) fn insert_prototype(&self, key: JsPrototype, value: &Gc<'static, SharedShapeInner>) {
+    /// Insert a property transition.
+    pub(super) fn insert_property(
+        &self,
+        key: TransitionKey,
+        value: &Gc<'static, SharedShapeInner>,
+    ) {
+        self.insert_property_in(&unsafe { boa_gc::MutationContext::global() }, key, value)
+    }
+
+    /// Insert a prototype transition using the given context.
+    pub(super) fn insert_prototype_in(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        key: JsPrototype,
+        value: &Gc<'static, SharedShapeInner>,
+    ) {
         let mut this = self.inner.borrow_mut();
         let prototypes = this.prototypes.get_or_insert_with(Box::default);
 
@@ -83,10 +95,12 @@ impl ForwardTransition {
             prototypes.map.retain(|_, v| v.is_upgradable());
         }
 
-        prototypes.map.insert(
-            key,
-            WeakGc::new(&unsafe { boa_gc::MutationContext::global() }, value),
-        );
+        prototypes.map.insert(key, WeakGc::new(mc, value));
+    }
+
+    /// Insert a prototype transition.
+    pub(super) fn insert_prototype(&self, key: JsPrototype, value: &Gc<'static, SharedShapeInner>) {
+        self.insert_prototype_in(&unsafe { boa_gc::MutationContext::global() }, key, value)
     }
 
     /// Get a property transition, return [`None`] otherwise.
diff --git a/core/engine/src/object/shape/shared_shape/mod.rs b/core/engine/src/object/shape/shared_shape/mod.rs
index cbbfb1dbecb..3448ac5455a 100644
--- a/core/engine/src/object/shape/shared_shape/mod.rs
+++ b/core/engine/src/object/shape/shared_shape/mod.rs
@@ -163,32 +163,50 @@ impl SharedShape {
         self.inner.prototype.as_ref() == Some(prototype)
     }
 
-    /// Create a new [`SharedShape`].
-    fn new(inner: Inner) -> Self {
+    /// Create a new [`SharedShape`] using the given context.
+    fn new_in(mc: &boa_gc::MutationContext<'static, '_>, inner: Inner) -> Self {
         Self {
-            inner: Gc::new(&unsafe { boa_gc::MutationContext::global() }, inner),
+            inner: Gc::new(mc, inner),
         }
     }
 
+    /// Create a new [`SharedShape`].
+    fn new(inner: Inner) -> Self {
+        Self::new_in(&unsafe { boa_gc::MutationContext::global() }, inner)
+    }
+
+    /// Create a root [`SharedShape`] using the given context.
+    #[must_use]
+    pub(crate) fn root_in(mc: &boa_gc::MutationContext<'static, '_>) -> Self {
+        Self::new_in(
+            mc,
+            Inner {
+                forward_transitions: ForwardTransition::default(),
+                prototype: None,
+                property_count: 0,
+                // Most of the time the root shape initiates with between 1-4 properties.
+                property_table: PropertyTable::with_capacity(4),
+                previous: None,
+                flags: ShapeFlags::default(),
+                transition_count: 0,
+            },
+        )
+    }
+
     /// Create a root [`SharedShape`].
     #[must_use]
     pub(crate) fn root() -> Self {
-        Self::new(Inner {
-            forward_transitions: ForwardTransition::default(),
-            prototype: None,
-            property_count: 0,
-            // Most of the time the root shape initiates with between 1-4 properties.
-            property_table: PropertyTable::with_capacity(4),
-            previous: None,
-            flags: ShapeFlags::default(),
-            transition_count: 0,
-        })
+        Self::root_in(&unsafe { boa_gc::MutationContext::global() })
     }
 
-    /// Create a [`SharedShape`] change prototype transition.
-    pub(crate) fn change_prototype_transition(&self, prototype: JsPrototype) -> Self {
+    /// Create a [`SharedShape`] change prototype transition using the given context.
+    pub(crate) fn change_prototype_transition_in(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        prototype: JsPrototype,
+    ) -> Self {
         if let Some(shape) = self.forward_transitions().get_prototype(&prototype) {
-            if let Some(inner) = shape.upgrade(&unsafe { boa_gc::MutationContext::global() }) {
+            if let Some(inner) = shape.upgrade(mc) {
                 return Self { inner };
             }
 
@@ -203,7 +221,7 @@ impl SharedShape {
             transition_count: self.transition_count() + 1,
             flags: ShapeFlags::prototype_transition_from(self.flags()),
         };
-        let new_shape = Self::new(new_inner_shape);
+        let new_shape = Self::new_in(mc, new_inner_shape);
 
         self.forward_transitions()
             .insert_prototype(prototype, &new_shape.inner);
@@ -211,11 +229,23 @@ impl SharedShape {
         new_shape
     }
 
-    /// Create a [`SharedShape`] insert property transition.
-    pub(crate) fn insert_property_transition(&self, key: TransitionKey) -> Self {
+    /// Create a [`SharedShape`] change prototype transition.
+    pub(crate) fn change_prototype_transition(&self, prototype: JsPrototype) -> Self {
+        self.change_prototype_transition_in(
+            &unsafe { boa_gc::MutationContext::global() },
+            prototype,
+        )
+    }
+
+    /// Create a [`SharedShape`] insert property transition using the given context.
+    pub(crate) fn insert_property_transition_in(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        key: TransitionKey,
+    ) -> Self {
         // Check if we have already created such a transition, if so use it!
         if let Some(shape) = self.forward_transitions().get_property(&key) {
-            if let Some(inner) = shape.upgrade(&unsafe { boa_gc::MutationContext::global() }) {
+            if let Some(inner) = shape.upgrade(mc) {
                 return Self { inner };
             }
 
@@ -236,7 +266,7 @@ impl SharedShape {
             transition_count: self.transition_count() + 1,
             flags: ShapeFlags::insert_property_transition_from(self.flags()),
         };
-        let new_shape = Self::new(new_inner_shape);
+        let new_shape = Self::new_in(mc, new_inner_shape);
 
         self.forward_transitions()
             .insert_property(key, &new_shape.inner);
@@ -244,16 +274,30 @@ impl SharedShape {
         new_shape
     }
 
+    /// Create a [`SharedShape`] insert property transition.
+    pub(crate) fn insert_property_transition(&self, key: TransitionKey) -> Self {
+        self.insert_property_transition_in(&unsafe { boa_gc::MutationContext::global() }, key)
+    }
+
     /// Create a [`SharedShape`] change prototype transition, returning [`ChangeTransition`].
     pub(crate) fn change_attributes_transition(
         &self,
         key: TransitionKey,
+    ) -> ChangeTransition<Self> {
+        self.change_attributes_transition_in(&unsafe { boa_gc::MutationContext::global() }, key)
+    }
+
+    /// Create a [`SharedShape`] change prototype transition using the given context, returning [`ChangeTransition`].
+    pub(crate) fn change_attributes_transition_in(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        key: TransitionKey,
     ) -> ChangeTransition<Self> {
         let slot = self.property_table().get_expect(&key.property_key);
 
         // Check if we have already created such a transition, if so use it!
         if let Some(shape) = self.forward_transitions().get_property(&key) {
-            if let Some(inner) = shape.upgrade(&unsafe { boa_gc::MutationContext::global() }) {
+            if let Some(inner) = shape.upgrade(mc) {
                 let action = if slot.attributes.width_match(key.attributes) {
                     ChangeTransitionAction::Nothing
                 } else if slot.attributes.is_accessor_descriptor() {
@@ -412,13 +456,17 @@ impl SharedShape {
         (base, prototype, transitions)
     }
 
-    /// Remove a property from [`SharedShape`], returning the new [`SharedShape`].
-    pub(crate) fn remove_property_transition(&self, key: &PropertyKey) -> Self {
+    /// Remove a property from [`SharedShape`], returning the new [`SharedShape`] using the given context.
+    pub(crate) fn remove_property_transition_in(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        key: &PropertyKey,
+    ) -> Self {
         let (mut base, prototype, transitions) = self.rollback_before(key);
 
         // Apply prototype transition, if it was found.
         if let Some(prototype) = prototype {
-            base = base.change_prototype_transition(prototype);
+            base = base.change_prototype_transition_in(mc, prototype);
         }
 
         for (property_key, attributes) in transitions.into_iter().rev() {
@@ -426,12 +474,17 @@ impl SharedShape {
                 property_key,
                 attributes,
             };
-            base = base.insert_property_transition(transition);
+            base = base.insert_property_transition_in(mc, transition);
         }
 
         base
     }
 
+    /// Remove a property from [`SharedShape`], returning the new [`SharedShape`].
+    pub(crate) fn remove_property_transition(&self, key: &PropertyKey) -> Self {
+        self.remove_property_transition_in(&unsafe { boa_gc::MutationContext::global() }, key)
+    }
+
     /// Do a property lookup, returns [`None`] if property not found.
     pub(crate) fn lookup(&self, key: &PropertyKey) -> Option<Slot> {
         let property_count = self.property_count();
@@ -481,27 +534,39 @@ pub(crate) struct WeakSharedShape {
 
 impl WeakSharedShape {
     /// Upgrade returns a [`SharedShape`] pointer for the internal value if the pointer is still live,
-    /// or [`None`] if the value was already garbage collected.
+    /// or [`None`] if the value was already garbage collected, using the given context.
     #[inline]
     #[must_use]
-    pub(crate) fn upgrade(&self) -> Option<SharedShape> {
+    pub(crate) fn upgrade_in(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+    ) -> Option<SharedShape> {
         Some(SharedShape {
-            inner: self
-                .inner
-                .upgrade(&unsafe { boa_gc::MutationContext::global() })?,
+            inner: self.inner.upgrade(mc)?,
         })
     }
 
+    /// Upgrade returns a [`SharedShape`] pointer for the internal value if the pointer is still live,
+    /// or [`None`] if the value was already garbage collected.
+    #[inline]
+    #[must_use]
+    pub(crate) fn upgrade(&self) -> Option<SharedShape> {
+        self.upgrade_in(&unsafe { boa_gc::MutationContext::global() })
+    }
+
     #[allow(dead_code)]
     pub(crate) fn is_upgradable(&self) -> bool {
         self.inner.is_upgradable()
     }
+    pub(crate) fn new_in(mc: &boa_gc::MutationContext<'static, '_>, value: &SharedShape) -> Self {
+        WeakSharedShape {
+            inner: WeakGc::new(mc, &value.inner),
+        }
+    }
 }
 
 impl From<&SharedShape> for WeakSharedShape {
     fn from(value: &SharedShape) -> Self {
-        WeakSharedShape {
-            inner: WeakGc::new(&unsafe { boa_gc::MutationContext::global() }, &value.inner),
-        }
+        Self::new_in(&unsafe { boa_gc::MutationContext::global() }, value)
     }
 }
diff --git a/core/engine/src/object/shape/shared_shape/template.rs b/core/engine/src/object/shape/shared_shape/template.rs
index 2e6c9fb90cb..0359b79153a 100644
--- a/core/engine/src/object/shape/shared_shape/template.rs
+++ b/core/engine/src/object/shape/shared_shape/template.rs
@@ -27,10 +27,23 @@ impl ObjectTemplate {
         }
     }
 
+    /// Create and [`ObjectTemplate`] with a prototype using the given context.
+    pub(crate) fn with_prototype_in(
+        mc: &boa_gc::MutationContext<'static, '_>,
+        shape: &SharedShape,
+        prototype: JsObject,
+    ) -> Self {
+        let shape = shape.change_prototype_transition_in(mc, Some(prototype));
+        Self { shape }
+    }
+
     /// Create and [`ObjectTemplate`] with a prototype.
     pub(crate) fn with_prototype(shape: &SharedShape, prototype: JsObject) -> Self {
-        let shape = shape.change_prototype_transition(Some(prototype));
-        Self { shape }
+        Self::with_prototype_in(
+            &unsafe { boa_gc::MutationContext::global() },
+            shape,
+            prototype,
+        )
     }
 
     /// Check if the shape has a specific, prototype.
@@ -38,12 +51,25 @@ impl ObjectTemplate {
         self.shape.has_prototype(prototype)
     }
 
+    /// Set the prototype of the [`ObjectTemplate`] using the given context.
+    ///
+    /// This assumes that the prototype has not been set yet.
+    pub(crate) fn set_prototype_in(
+        &mut self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        prototype: JsObject,
+    ) -> &mut Self {
+        self.shape = self
+            .shape
+            .change_prototype_transition_in(mc, Some(prototype));
+        self
+    }
+
     /// Set the prototype of the [`ObjectTemplate`].
     ///
     /// This assumes that the prototype has not been set yet.
     pub(crate) fn set_prototype(&mut self, prototype: JsObject) -> &mut Self {
-        self.shape = self.shape.change_prototype_transition(Some(prototype));
-        self
+        self.set_prototype_in(&unsafe { boa_gc::MutationContext::global() }, prototype)
     }
 
     /// Returns the inner shape of the [`ObjectTemplate`].
@@ -51,33 +77,51 @@ impl ObjectTemplate {
         &self.shape
     }
 
-    /// Add a data property to the [`ObjectTemplate`].
+    /// Add a data property to the [`ObjectTemplate`] using the given context.
     ///
     /// This assumes that the property with the given key was not previously set
     /// and that it's a string or symbol.
-    pub(crate) fn property(&mut self, key: PropertyKey, attributes: Attribute) -> &mut Self {
+    pub(crate) fn property_in(
+        &mut self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        key: PropertyKey,
+        attributes: Attribute,
+    ) -> &mut Self {
         debug_assert!(!matches!(&key, PropertyKey::Index(_)));
 
-        let attributes = SlotAttributes::from_bits_truncate(attributes.bits());
-        self.shape = self.shape.insert_property_transition(TransitionKey {
+        let transition = TransitionKey {
             property_key: key,
-            attributes,
-        });
+            attributes: SlotAttributes::from_bits_truncate(attributes.bits()),
+        };
+        self.shape = self.shape.insert_property_transition_in(mc, transition);
         self
     }
 
+    /// Add a data property to the [`ObjectTemplate`].
+    ///
+    /// This assumes that the property with the given key was not previously set
+    /// and that it's a string or symbol.
+    pub(crate) fn property(&mut self, key: PropertyKey, attributes: Attribute) -> &mut Self {
+        self.property_in(
+            &unsafe { boa_gc::MutationContext::global() },
+            key,
+            attributes,
+        )
+    }
+
     /// Add a accessor property to the [`ObjectTemplate`].
     ///
     /// This assumes that the property with the given key was not previously set
     /// and that it's a string or symbol.
-    pub(crate) fn accessor(
+    /// Add a accessor property to the [`ObjectTemplate`] using the given context.
+    pub(crate) fn accessor_in(
         &mut self,
+        mc: &boa_gc::MutationContext<'static, '_>,
         key: PropertyKey,
         get: bool,
         set: bool,
         attributes: Attribute,
     ) -> &mut Self {
-        // TODO: We don't support indexed keys.
         debug_assert!(!matches!(&key, PropertyKey::Index(_)));
 
         let attributes = {
@@ -97,29 +141,66 @@ impl ObjectTemplate {
             result
         };
 
-        self.shape = self.shape.insert_property_transition(TransitionKey {
-            property_key: key,
-            attributes,
-        });
+        self.shape = self.shape.insert_property_transition_in(
+            mc,
+            TransitionKey {
+                property_key: key,
+                attributes,
+            },
+        );
         self
     }
 
-    /// Create an object from the [`ObjectTemplate`]
+    /// Add a accessor property to the [`ObjectTemplate`].
     ///
-    /// The storage must match the properties provided.
-    pub(crate) fn create<T: NativeObject>(&self, data: T, storage: Vec<JsValue>) -> JsObject {
+    /// This assumes that the property with the given key was not previously set
+    /// and that it's a string or symbol.
+    pub(crate) fn accessor(
+        &mut self,
+        key: PropertyKey,
+        get: bool,
+        set: bool,
+        attributes: Attribute,
+    ) -> &mut Self {
+        self.accessor_in(
+            &unsafe { boa_gc::MutationContext::global() },
+            key,
+            get,
+            set,
+            attributes,
+        )
+    }
+
+    /// Create an object from the [`ObjectTemplate`] using the given context.
+    pub(crate) fn create_in<T: NativeObject>(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        data: T,
+        storage: Vec<JsValue>,
+    ) -> JsObject {
         let internal_methods = data.internal_methods();
 
+        let mut properties = PropertyMap::new(
+            self.shape.clone().into(),
+            crate::object::IndexedProperties::default(),
+        );
+        properties.storage = storage;
+
         let mut object = Object {
             data: ObjectData::new(data),
             extensible: true,
-            properties: PropertyMap::new(self.shape.clone().into(), IndexedProperties::default()),
+            properties,
             private_elements: ThinVec::new(),
         };
 
-        object.properties.storage = storage;
+        JsObject::from_object_and_vtable_in(mc, object, internal_methods)
+    }
 
-        JsObject::from_object_and_vtable(object, internal_methods)
+    /// Create an object from the [`ObjectTemplate`]
+    ///
+    /// The storage must match the properties provided.
+    pub(crate) fn create<T: NativeObject>(&self, data: T, storage: Vec<JsValue>) -> JsObject {
+        self.create_in(&unsafe { boa_gc::MutationContext::global() }, data, storage)
     }
 
     /// Create an object from the [`ObjectTemplate`]
diff --git a/core/engine/src/object/shape/unique_shape.rs b/core/engine/src/object/shape/unique_shape.rs
index b050e4bf5eb..2b19a497af4 100644
--- a/core/engine/src/object/shape/unique_shape.rs
+++ b/core/engine/src/object/shape/unique_shape.rs
@@ -34,11 +34,15 @@ pub(crate) struct UniqueShape {
 }
 
 impl UniqueShape {
-    /// Create a new [`UniqueShape`].
-    pub(crate) fn new(prototype: JsPrototype, property_table: PropertyTableInner) -> Self {
+    /// Create a new [`UniqueShape`] using the given context.
+    pub(crate) fn new_in(
+        mc: &boa_gc::MutationContext<'static, '_>,
+        prototype: JsPrototype,
+        property_table: PropertyTableInner,
+    ) -> Self {
         Self {
             inner: Gc::new(
-                &unsafe { boa_gc::MutationContext::global() },
+                mc,
                 Inner {
                     property_table: RefCell::new(property_table),
                     prototype: GcRefCell::new(prototype),
@@ -47,6 +51,15 @@ impl UniqueShape {
         }
     }
 
+    /// Create a new [`UniqueShape`].
+    pub(crate) fn new(prototype: JsPrototype, property_table: PropertyTableInner) -> Self {
+        Self::new_in(
+            &unsafe { boa_gc::MutationContext::global() },
+            prototype,
+            property_table,
+        )
+    }
+
     pub(crate) fn override_internal(
         &self,
         property_table: PropertyTableInner,
@@ -254,27 +267,39 @@ pub(crate) struct WeakUniqueShape {
 
 impl WeakUniqueShape {
     /// Upgrade returns a [`UniqueShape`] pointer for the internal value if the pointer is still live,
-    /// or [`None`] if the value was already garbage collected.
+    /// or [`None`] if the value was already garbage collected, using the given context.
     #[inline]
     #[must_use]
-    pub(crate) fn upgrade(&self) -> Option<UniqueShape> {
+    pub(crate) fn upgrade_in(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+    ) -> Option<UniqueShape> {
         Some(UniqueShape {
-            inner: self
-                .inner
-                .upgrade(&unsafe { boa_gc::MutationContext::global() })?,
+            inner: self.inner.upgrade(mc)?,
         })
     }
 
+    /// Upgrade returns a [`UniqueShape`] pointer for the internal value if the pointer is still live,
+    /// or [`None`] if the value was already garbage collected.
+    #[inline]
+    #[must_use]
+    pub(crate) fn upgrade(&self) -> Option<UniqueShape> {
+        self.upgrade_in(&unsafe { boa_gc::MutationContext::global() })
+    }
+
     #[allow(dead_code)]
     pub(crate) fn is_upgradable(&self) -> bool {
         self.inner.is_upgradable()
     }
+    pub(crate) fn new_in(mc: &boa_gc::MutationContext<'static, '_>, value: &UniqueShape) -> Self {
+        WeakUniqueShape {
+            inner: WeakGc::new(mc, &value.inner),
+        }
+    }
 }
 
 impl From<&UniqueShape> for WeakUniqueShape {
     fn from(value: &UniqueShape) -> Self {
-        WeakUniqueShape {
-            inner: WeakGc::new(&unsafe { boa_gc::MutationContext::global() }, &value.inner),
-        }
+        Self::new_in(&unsafe { boa_gc::MutationContext::global() }, value)
     }
 }
diff --git a/core/engine/src/realm.rs b/core/engine/src/realm.rs
index c133ce823eb..a1d0ec1c8b1 100644
--- a/core/engine/src/realm.rs
+++ b/core/engine/src/realm.rs
@@ -77,8 +77,12 @@ struct Inner {
 impl Realm {
     /// Create a new [`Realm`].
     #[inline]
-    pub fn create(hooks: &dyn HostHooks, root_shape: &RootShape) -> JsResult<Self> {
-        let intrinsics = Intrinsics::uninit(root_shape).ok_or_else(|| {
+    pub fn create(
+        hooks: &dyn HostHooks,
+        root_shape: &RootShape,
+        mc: &boa_gc::MutationContext<'static, '_>,
+    ) -> JsResult<Self> {
+        let intrinsics = Intrinsics::uninit(root_shape, mc).ok_or_else(|| {
             JsNativeError::typ().with_message("failed to create the realm intrinsics")
         })?;
 
@@ -86,15 +90,12 @@ impl Realm {
         let global_this = hooks
             .create_global_this(&intrinsics)
             .unwrap_or_else(|| global_object.clone());
-        let environment = Gc::new(
-            &unsafe { boa_gc::MutationContext::global() },
-            DeclarativeEnvironment::global(),
-        );
+        let environment = Gc::new(mc, DeclarativeEnvironment::global());
         let scope = Scope::new_global();
 
         let realm = Self {
             inner: Gc::new(
-                &unsafe { boa_gc::MutationContext::global() },
+                mc,
                 Inner {
                     intrinsics,
                     environment,
diff --git a/core/engine/src/script.rs b/core/engine/src/script.rs
index ef9823a32cf..373129572b9 100644
--- a/core/engine/src/script.rs
+++ b/core/engine/src/script.rs
@@ -137,6 +137,7 @@ impl Script {
 
             let spanned_source_text = SpannedSourceText::new_source_only(self.get_source());
 
+            let mc = context.gc_collector();
             let mut compiler = ByteCompiler::new(
                 js_string!("<main>"),
                 source.strict(),
@@ -146,9 +147,14 @@ impl Script {
                 false,
                 false,
                 context.interner_mut(),
+                &mc,
                 false,
                 spanned_source_text,
-                self.path().map(Path::to_owned).into(),
+                self.inner
+                    .path
+                    .as_deref()
+                    .map(std::path::Path::to_path_buf)
+                    .into(),
             );
 
             #[cfg(feature = "annex-b")]
diff --git a/core/engine/src/vm/mod.rs b/core/engine/src/vm/mod.rs
index 48d957adfaf..cc4ee8247b7 100644
--- a/core/engine/src/vm/mod.rs
+++ b/core/engine/src/vm/mod.rs
@@ -404,13 +404,10 @@ impl ActiveRunnable {
 
 impl Vm {
     /// Creates a new virtual machine.
-    pub(crate) fn new(realm: Realm) -> Self {
+    pub(crate) fn new(realm: Realm, mc: &boa_gc::MutationContext<'static, '_>) -> Self {
         let mut frames = Vec::with_capacity(16);
         frames.push(CallFrame::new(
-            Gc::new(
-                &unsafe { boa_gc::MutationContext::global() },
-                CodeBlock::new(JsString::default(), 0, true),
-            ),
+            Gc::new(mc, CodeBlock::new(JsString::default(), 0, true)),
             None,
             EnvironmentStack::new(),
             realm,
diff --git a/core/engine/src/vm/opcode/push/environment.rs b/core/engine/src/vm/opcode/push/environment.rs
index 0d8b34ef974..a1eb7a76926 100644
--- a/core/engine/src/vm/opcode/push/environment.rs
+++ b/core/engine/src/vm/opcode/push/environment.rs
@@ -18,13 +18,12 @@ impl PushScope {
     #[inline(always)]
     pub(crate) fn operation(index: IndexOperand, context: &mut Context) {
         let scope = context.vm.frame().code_block().constant_scope(index.into());
+        let mc = context.gc_collector();
         let frame = context.vm.frame_mut();
         let global = frame.realm.environment();
         frame
             .environments
-            .push_lexical(scope.num_bindings_non_local(), global, unsafe {
-                boa_gc::MutationContext::global()
-            });
+            .push_lexical(scope.num_bindings_non_local(), global, mc);
     }
 }
 
diff --git a/core/gc/src/context.rs b/core/gc/src/context.rs
index 81624d8aee5..b3857952074 100644
--- a/core/gc/src/context.rs
+++ b/core/gc/src/context.rs
@@ -12,6 +12,13 @@ impl Default for GcContext {
     }
 }
 
+#[cfg(feature = "oscars_backend")]
+struct SyncWrapper(MutationContext<'static, 'static>);
+#[cfg(feature = "oscars_backend")]
+unsafe impl Sync for SyncWrapper {}
+#[cfg(feature = "oscars_backend")]
+unsafe impl Send for SyncWrapper {}
+
 #[cfg(feature = "oscars_backend")]
 impl GcContext {
     #[must_use]
@@ -20,17 +27,15 @@ impl GcContext {
     }
 
     pub fn alloc<T: crate::Trace + crate::Finalize + 'static>(&self, value: T) -> Gc<'static, T> {
-        // As a bridge, we use the global MutationContext until explicit
-        // context threading is natively supported by the oscars backend.
         let mc = MutationContext::global();
         Gc::new(&mc, value)
     }
 
     #[must_use]
-    pub fn gc_collector(&self) -> &MutationContext<'static, 'static> {
-        // Just return a dummy global mutation context
-        // This is safe for the bridge phase.
-        unimplemented!("Not supported natively without closure yet, use MutationContext::global()")
+    pub fn gc_collector(&self) -> &'static MutationContext<'static, 'static> {
+        static DUMMY: std::sync::LazyLock<SyncWrapper> =
+            std::sync::LazyLock::new(|| SyncWrapper(MutationContext::global()));
+        &DUMMY.0
     }
 }
 
@@ -45,6 +50,13 @@ impl Default for GcContext {
     }
 }
 
+#[cfg(not(feature = "oscars_backend"))]
+struct SyncWrapperDefault(crate::MutationContext<'static, 'static>);
+#[cfg(not(feature = "oscars_backend"))]
+unsafe impl Sync for SyncWrapperDefault {}
+#[cfg(not(feature = "oscars_backend"))]
+unsafe impl Send for SyncWrapperDefault {}
+
 #[cfg(not(feature = "oscars_backend"))]
 impl GcContext {
     #[must_use]
@@ -58,10 +70,9 @@ impl GcContext {
     }
 
     #[must_use]
-    pub fn gc_collector(&self) -> &crate::MutationContext<'static, 'static> {
-        // Just return a dummy global mutation context
-        static DUMMY: crate::MutationContext<'static, 'static> =
-            unsafe { crate::MutationContext::global() };
-        &DUMMY
+    pub fn gc_collector(&self) -> &'static crate::MutationContext<'static, 'static> {
+        static DUMMY: SyncWrapperDefault =
+            SyncWrapperDefault(unsafe { crate::MutationContext::global() });
+        &DUMMY.0
     }
 }

From 282344b4bc7eeef0cbd0db2083b2f8897f64c595 Mon Sep 17 00:00:00 2001
From: shruti2522 <shruti.apc01@gmail.com>
Date: Mon, 17 Aug 2026 15:35:24 +0000
Subject: [PATCH 04/19] Thread MutationContext through buitlin standard library
 objects

---
 cli/src/debug/limits.rs                       | 104 +++++----
 cli/src/debug/optimizer.rs                    |  28 ++-
 core/engine/benches/full.rs                   |   2 +-
 .../src/builtins/array/array_iterator.rs      |   5 +-
 core/engine/src/builtins/array/mod.rs         |  77 ++++---
 core/engine/src/builtins/array_buffer/mod.rs  |  16 +-
 .../src/builtins/array_buffer/shared.rs       |  13 +-
 .../engine/src/builtins/async_function/mod.rs |   4 +-
 .../src/builtins/async_generator/mod.rs       |   6 +-
 .../builtins/async_generator_function/mod.rs  |   4 +-
 core/engine/src/builtins/atomics/mod.rs       |  10 +-
 core/engine/src/builtins/bigint/mod.rs        |   4 +-
 core/engine/src/builtins/boolean/mod.rs       |  12 +-
 core/engine/src/builtins/builder.rs           |  54 +++--
 core/engine/src/builtins/dataview/mod.rs      |  11 +-
 core/engine/src/builtins/date/mod.rs          |  16 +-
 core/engine/src/builtins/error/aggregate.rs   |   5 +-
 core/engine/src/builtins/error/eval.rs        |   4 +-
 core/engine/src/builtins/error/mod.rs         |  10 +-
 core/engine/src/builtins/error/range.rs       |   4 +-
 core/engine/src/builtins/error/reference.rs   |   4 +-
 core/engine/src/builtins/error/syntax.rs      |   4 +-
 core/engine/src/builtins/error/type.rs        |   8 +-
 core/engine/src/builtins/error/uri.rs         |   4 +-
 core/engine/src/builtins/escape/mod.rs        |   8 +-
 core/engine/src/builtins/eval/mod.rs          |   4 +-
 .../src/builtins/finalization_registry/mod.rs |   5 +-
 .../engine/src/builtins/function/arguments.rs |   2 +
 core/engine/src/builtins/function/bound.rs    |   1 +
 core/engine/src/builtins/function/mod.rs      |  14 +-
 core/engine/src/builtins/function/tests.rs    |   3 +-
 core/engine/src/builtins/generator/mod.rs     |   4 +-
 .../src/builtins/generator_function/mod.rs    |   4 +-
 core/engine/src/builtins/intl/collator/mod.rs |  18 +-
 .../src/builtins/intl/date_time_format/mod.rs |  10 +-
 .../src/builtins/intl/list_format/mod.rs      |  27 +--
 core/engine/src/builtins/intl/locale/mod.rs   |  52 +++--
 core/engine/src/builtins/intl/mod.rs          |   4 +-
 .../src/builtins/intl/number_format/mod.rs    |   8 +-
 core/engine/src/builtins/intl/options.rs      |   1 +
 .../src/builtins/intl/plural_rules/mod.rs     |   5 +-
 .../src/builtins/intl/segmenter/iterator.rs   |   5 +-
 .../engine/src/builtins/intl/segmenter/mod.rs |  14 +-
 .../src/builtins/intl/segmenter/segments.rs   |   5 +-
 .../iterable/async_from_sync_iterator.rs      |   9 +-
 .../builtins/iterable/iterator_constructor.rs |   6 +-
 .../builtins/iterable/iterator_helper/mod.rs  |   5 +-
 .../builtins/iterable/iterator_prototype.rs   |  35 +--
 core/engine/src/builtins/iterable/mod.rs      |  56 +++--
 .../iterable/wrap_for_valid_iterator.rs       |   4 +-
 core/engine/src/builtins/json/mod.rs          |  12 +-
 core/engine/src/builtins/map/map_iterator.rs  |   5 +-
 core/engine/src/builtins/map/mod.rs           |  20 +-
 core/engine/src/builtins/math/mod.rs          |   4 +-
 core/engine/src/builtins/mod.rs               | 192 ++++++++--------
 core/engine/src/builtins/number/globals.rs    |  16 +-
 core/engine/src/builtins/number/mod.rs        |  12 +-
 .../src/builtins/object/for_in_iterator.rs    |  14 +-
 core/engine/src/builtins/object/mod.rs        |  23 +-
 core/engine/src/builtins/options.rs           |   7 +-
 core/engine/src/builtins/promise/mod.rs       |  43 +++-
 core/engine/src/builtins/proxy/mod.rs         |   9 +-
 core/engine/src/builtins/reflect/mod.rs       |   4 +-
 core/engine/src/builtins/regexp/mod.rs        |  44 ++--
 .../builtins/regexp/regexp_string_iterator.rs |   5 +-
 core/engine/src/builtins/set/mod.rs           |  15 +-
 core/engine/src/builtins/set/set_iterator.rs  |   5 +-
 core/engine/src/builtins/string/mod.rs        |  18 +-
 .../src/builtins/string/string_iterator.rs    |   5 +-
 core/engine/src/builtins/symbol/mod.rs        |   8 +-
 .../src/builtins/temporal/duration/mod.rs     |  43 ++--
 .../src/builtins/temporal/instant/mod.rs      |  28 ++-
 core/engine/src/builtins/temporal/mod.rs      |   4 +-
 core/engine/src/builtins/temporal/now.rs      |   4 +-
 .../src/builtins/temporal/plain_date/mod.rs   |  66 +++---
 .../builtins/temporal/plain_date_time/mod.rs  |  81 +++----
 .../builtins/temporal/plain_month_day/mod.rs  |  24 +-
 .../src/builtins/temporal/plain_time/mod.rs   |  48 ++--
 .../builtins/temporal/plain_year_month/mod.rs |  47 ++--
 .../builtins/temporal/zoneddatetime/mod.rs    | 109 +++++----
 .../src/builtins/typed_array/builtin.rs       |  48 ++--
 core/engine/src/builtins/typed_array/mod.rs   |   6 +-
 core/engine/src/builtins/uri/mod.rs           |  16 +-
 core/engine/src/builtins/weak/weak_ref.rs     |   5 +-
 core/engine/src/builtins/weak_map/mod.rs      |   5 +-
 core/engine/src/builtins/weak_set/mod.rs      |   5 +-
 core/engine/src/class.rs                      |  16 +-
 core/engine/src/context/hooks.rs              |   8 +-
 core/engine/src/context/intrinsics.rs         | 117 +++++-----
 core/engine/src/context/mod.rs                |   6 +-
 core/engine/src/error/mod.rs                  |   1 +
 core/engine/src/module/mod.rs                 |  12 +-
 core/engine/src/module/namespace.rs           |   1 +
 core/engine/src/module/source.rs              |   2 +
 core/engine/src/native_function/mod.rs        |   9 +-
 .../src/object/builtins/jsarraybuffer.rs      |   1 +
 core/engine/src/object/builtins/jsdataview.rs |   1 +
 core/engine/src/object/builtins/jsdate.rs     |  11 +-
 core/engine/src/object/builtins/jsfunction.rs |   2 +-
 core/engine/src/object/builtins/jsmap.rs      |   2 +
 core/engine/src/object/builtins/jspromise.rs  |  26 ++-
 core/engine/src/object/builtins/jsproxy.rs    |  72 ++++--
 core/engine/src/object/builtins/jsset.rs      |   2 +
 .../object/builtins/jssharedarraybuffer.rs    |   2 +-
 .../src/object/builtins/jstypedarray.rs       |  12 +-
 core/engine/src/object/builtins/jsweakmap.rs  |   1 +
 core/engine/src/object/builtins/jsweakset.rs  |   1 +
 core/engine/src/object/datatypes.rs           |   2 +-
 .../engine/src/object/internal_methods/mod.rs |  31 ++-
 core/engine/src/object/jsobject.rs            | 210 +++++-------------
 core/engine/src/object/mod.rs                 | 177 ++++++++++-----
 core/engine/src/object/property_map.rs        |  31 ++-
 core/engine/src/object/shape/mod.rs           |  64 ++----
 core/engine/src/object/shape/root_shape.rs    |  11 +-
 .../shape/shared_shape/forward_transition.rs  |  14 +-
 .../src/object/shape/shared_shape/mod.rs      |  82 ++-----
 .../src/object/shape/shared_shape/template.rs |  60 +----
 .../src/object/shape/shared_shape/tests.rs    |  58 +++--
 core/engine/src/object/shape/unique_shape.rs  |  46 ++--
 core/engine/src/realm.rs                      |   4 +-
 core/engine/src/symbol.rs                     |  11 +-
 .../src/value/conversions/serde_json.rs       |  17 +-
 core/engine/src/value/inner/nan_boxed.rs      |   2 +-
 core/engine/src/value/mod.rs                  |  60 ++---
 core/engine/src/value/tests.rs                |  10 +-
 core/engine/src/vm/code_block.rs              |  52 +++--
 core/engine/src/vm/inline_cache/mod.rs        |  16 +-
 core/engine/src/vm/inline_cache/tests.rs      |  64 +++---
 core/engine/src/vm/opcode/await/mod.rs        |   2 +
 core/engine/src/vm/opcode/call/mod.rs         |   3 +
 core/engine/src/vm/opcode/generator/mod.rs    |   2 +
 core/engine/src/vm/opcode/get/name.rs         |   4 +-
 core/engine/src/vm/opcode/get/property.rs     |   4 +-
 core/engine/src/vm/opcode/iteration/for_in.rs |   3 +-
 .../src/vm/opcode/iteration/iterator.rs       |   3 +-
 core/engine/src/vm/opcode/meta/mod.rs         |   2 +-
 core/engine/src/vm/opcode/push/array.rs       |  10 +-
 core/engine/src/vm/opcode/push/class/mod.rs   |   2 +-
 core/engine/src/vm/opcode/push/object.rs      |  10 +-
 .../src/vm/opcode/set/class_prototype.rs      |   1 +
 core/engine/src/vm/opcode/set/property.rs     |   4 +-
 core/macros/src/class.rs                      |  14 +-
 core/macros/src/lib.rs                        |   2 +-
 core/macros/src/module.rs                     |   6 +-
 core/runtime/src/console/mod.rs               |   2 +-
 core/runtime/src/fetch/headers_iterator.rs    |   6 +-
 core/runtime/src/fetch/mod.rs                 |   1 +
 core/runtime/src/process/mod.rs               |   2 +-
 core/runtime/src/store/to.rs                  |   2 +-
 core/runtime/src/test262.rs                   |   6 +-
 examples/src/bin/closures.rs                  |   3 +-
 examples/src/bin/jsarray.rs                   |   3 +
 examples/src/bin/jspromise.rs                 |   6 +-
 examples/src/bin/jstypedarray.rs              |   4 +
 examples/src/bin/modulehandler.rs             |   2 +-
 examples/src/bin/modules.rs                   |   4 +-
 examples/src/bin/synthetic.rs                 |   5 +
 tests/macros/tests/class.rs                   |   2 +-
 tests/macros/tests/fibonacci.rs               |   4 +-
 tests/macros/tests/gcd_callback.rs            |   2 +-
 tests/tester/src/exec/mod.rs                  |   1 +
 tests/wpt/src/lib.rs                          |   4 +-
 162 files changed, 1726 insertions(+), 1450 deletions(-)

diff --git a/cli/src/debug/limits.rs b/cli/src/debug/limits.rs
index 51ec1a900f8..b8370d7cb89 100644
--- a/cli/src/debug/limits.rs
+++ b/cli/src/debug/limits.rs
@@ -64,48 +64,72 @@ fn set_backtrace(_: &JsValue, args: &[JsValue], context: &mut Context) -> JsResu
 }
 
 pub(super) fn create_object(context: &mut Context) -> JsObject {
-    let get_loop =
-        FunctionObjectBuilder::new(context.realm(), NativeFunction::from_fn_ptr(get_loop))
-            .name(js_string!("get loop"))
-            .length(0)
-            .build();
-    let set_loop =
-        FunctionObjectBuilder::new(context.realm(), NativeFunction::from_fn_ptr(set_loop))
-            .name(js_string!("set loop"))
-            .length(1)
-            .build();
+    let get_loop = FunctionObjectBuilder::new(
+        context.realm(),
+        context.gc_collector(),
+        NativeFunction::from_fn_ptr(get_loop),
+    )
+    .name(js_string!("get loop"))
+    .length(0)
+    .build();
+    let set_loop = FunctionObjectBuilder::new(
+        context.realm(),
+        context.gc_collector(),
+        NativeFunction::from_fn_ptr(set_loop),
+    )
+    .name(js_string!("set loop"))
+    .length(1)
+    .build();
 
-    let get_stack =
-        FunctionObjectBuilder::new(context.realm(), NativeFunction::from_fn_ptr(get_stack))
-            .name(js_string!("get stack"))
-            .length(0)
-            .build();
-    let set_stack =
-        FunctionObjectBuilder::new(context.realm(), NativeFunction::from_fn_ptr(set_stack))
-            .name(js_string!("set stack"))
-            .length(1)
-            .build();
+    let get_stack = FunctionObjectBuilder::new(
+        context.realm(),
+        context.gc_collector(),
+        NativeFunction::from_fn_ptr(get_stack),
+    )
+    .name(js_string!("get stack"))
+    .length(0)
+    .build();
+    let set_stack = FunctionObjectBuilder::new(
+        context.realm(),
+        context.gc_collector(),
+        NativeFunction::from_fn_ptr(set_stack),
+    )
+    .name(js_string!("set stack"))
+    .length(1)
+    .build();
 
-    let get_recursion =
-        FunctionObjectBuilder::new(context.realm(), NativeFunction::from_fn_ptr(get_recursion))
-            .name(js_string!("get recursion"))
-            .length(0)
-            .build();
-    let set_recursion =
-        FunctionObjectBuilder::new(context.realm(), NativeFunction::from_fn_ptr(set_recursion))
-            .name(js_string!("set recursion"))
-            .length(1)
-            .build();
-    let get_backtrace =
-        FunctionObjectBuilder::new(context.realm(), NativeFunction::from_fn_ptr(get_backtrace))
-            .name(js_string!("get backtrace"))
-            .length(0)
-            .build();
-    let set_backtrace =
-        FunctionObjectBuilder::new(context.realm(), NativeFunction::from_fn_ptr(set_backtrace))
-            .name(js_string!("set backtrace"))
-            .length(1)
-            .build();
+    let get_recursion = FunctionObjectBuilder::new(
+        context.realm(),
+        context.gc_collector(),
+        NativeFunction::from_fn_ptr(get_recursion),
+    )
+    .name(js_string!("get recursion"))
+    .length(0)
+    .build();
+    let set_recursion = FunctionObjectBuilder::new(
+        context.realm(),
+        context.gc_collector(),
+        NativeFunction::from_fn_ptr(set_recursion),
+    )
+    .name(js_string!("set recursion"))
+    .length(1)
+    .build();
+    let get_backtrace = FunctionObjectBuilder::new(
+        context.realm(),
+        context.gc_collector(),
+        NativeFunction::from_fn_ptr(get_backtrace),
+    )
+    .name(js_string!("get backtrace"))
+    .length(0)
+    .build();
+    let set_backtrace = FunctionObjectBuilder::new(
+        context.realm(),
+        context.gc_collector(),
+        NativeFunction::from_fn_ptr(set_backtrace),
+    )
+    .name(js_string!("set backtrace"))
+    .length(1)
+    .build();
 
     ObjectInitializer::new(context)
         .accessor(
diff --git a/cli/src/debug/optimizer.rs b/cli/src/debug/optimizer.rs
index 20b33d85ba8..c5f868d9fb1 100644
--- a/cli/src/debug/optimizer.rs
+++ b/cli/src/debug/optimizer.rs
@@ -38,6 +38,7 @@ fn set_statistics(_: &JsValue, args: &[JsValue], context: &mut Context) -> JsRes
 pub(super) fn create_object(context: &mut Context) -> JsObject {
     let get_constant_folding = FunctionObjectBuilder::new(
         context.realm(),
+        context.gc_collector(),
         NativeFunction::from_fn_ptr(get_constant_folding),
     )
     .name("get constantFolding")
@@ -45,22 +46,29 @@ pub(super) fn create_object(context: &mut Context) -> JsObject {
     .build();
     let set_constant_folding = FunctionObjectBuilder::new(
         context.realm(),
+        context.gc_collector(),
         NativeFunction::from_fn_ptr(set_constant_folding),
     )
     .name("set constantFolding")
     .length(1)
     .build();
 
-    let get_statistics =
-        FunctionObjectBuilder::new(context.realm(), NativeFunction::from_fn_ptr(get_statistics))
-            .name("get statistics")
-            .length(0)
-            .build();
-    let set_statistics =
-        FunctionObjectBuilder::new(context.realm(), NativeFunction::from_fn_ptr(set_statistics))
-            .name("set statistics")
-            .length(1)
-            .build();
+    let get_statistics = FunctionObjectBuilder::new(
+        context.realm(),
+        context.gc_collector(),
+        NativeFunction::from_fn_ptr(get_statistics),
+    )
+    .name("get statistics")
+    .length(0)
+    .build();
+    let set_statistics = FunctionObjectBuilder::new(
+        context.realm(),
+        context.gc_collector(),
+        NativeFunction::from_fn_ptr(set_statistics),
+    )
+    .name("set statistics")
+    .length(1)
+    .build();
     ObjectInitializer::new(context)
         .accessor(
             js_string!("constantFolding"),
diff --git a/core/engine/benches/full.rs b/core/engine/benches/full.rs
index 78e6dfb5548..78cf1f27d7a 100644
--- a/core/engine/benches/full.rs
+++ b/core/engine/benches/full.rs
@@ -18,7 +18,7 @@ static ALLOC: jemallocator::Jemalloc = jemallocator::Jemalloc;
 
 fn create_realm(c: &mut Criterion) {
     c.bench_function("Create Realm", move |b| {
-        let root_shape = RootShape::default();
+        let root_shape = RootShape::new(&unsafe { boa_gc::MutationContext::global() });
         b.iter(|| {
             Realm::create(&DefaultHooks, &root_shape, &unsafe {
                 boa_gc::MutationContext::global()
diff --git a/core/engine/src/builtins/array/array_iterator.rs b/core/engine/src/builtins/array/array_iterator.rs
index 1c05b997c3b..2490214b261 100644
--- a/core/engine/src/builtins/array/array_iterator.rs
+++ b/core/engine/src/builtins/array/array_iterator.rs
@@ -37,8 +37,8 @@ pub(crate) struct ArrayIterator {
 }
 
 impl IntrinsicObject for ArrayIterator {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::with_intrinsic::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::with_intrinsic::<Self>(realm, mc)
             .prototype(realm.intrinsics().constructors().iterator().prototype())
             .static_method(Self::next, js_string!("next"), 0)
             .static_property(
@@ -78,6 +78,7 @@ impl ArrayIterator {
         context: &Context,
     ) -> JsValue {
         let array_iterator = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             context.intrinsics().objects().iterator_prototypes().array(),
             Self::new(array, kind),
diff --git a/core/engine/src/builtins/array/mod.rs b/core/engine/src/builtins/array/mod.rs
index acd695878ea..e07046b7978 100644
--- a/core/engine/src/builtins/array/mod.rs
+++ b/core/engine/src/builtins/array/mod.rs
@@ -76,11 +76,11 @@ impl JsData for Array {
 }
 
 impl IntrinsicObject for Array {
-    fn init(realm: &Realm) {
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
         let symbol_iterator = JsSymbol::iterator();
         let symbol_unscopables = JsSymbol::unscopables();
 
-        let get_species = BuiltInBuilder::callable(realm, Self::get_species)
+        let get_species = BuiltInBuilder::callable(realm, Self::get_species, mc)
             .name(js_string!("get [Symbol.species]"))
             .build();
 
@@ -88,6 +88,7 @@ impl IntrinsicObject for Array {
             realm,
             realm.intrinsics().objects().array_prototype_values().into(),
             Self::values,
+            mc,
         )
         .name(js_string!("values"))
         .build();
@@ -100,13 +101,14 @@ impl IntrinsicObject for Array {
                 .array_prototype_to_string()
                 .into(),
             Self::to_string,
+            mc,
         )
         .name(js_string!("toString"))
         .build();
 
-        let unscopables_object = Self::unscopables_object();
+        let unscopables_object = Self::unscopables_object(mc);
 
-        let builder = BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        let builder = BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             // Static Methods
             .static_method(Self::from, js_string!("from"), 1)
             .static_method(Self::is_array, js_string!("isArray"), 1)
@@ -333,11 +335,11 @@ impl Array {
 
         // Fast path:
         if prototype.is_none() {
-            return Ok(context
-                .intrinsics()
-                .templates()
-                .array()
-                .create(Array, vec![JsValue::new(length)]));
+            return Ok(context.intrinsics().templates().array().create(
+                context.gc_collector(),
+                Array,
+                vec![JsValue::new(length)],
+            ));
         }
 
         // 7. Return A.
@@ -355,16 +357,20 @@ impl Array {
             .array()
             .has_prototype(&prototype)
         {
-            return Ok(context
-                .intrinsics()
-                .templates()
-                .array()
-                .create(Array, vec![JsValue::new(length)]));
+            return Ok(context.intrinsics().templates().array().create(
+                context.gc_collector(),
+                Array,
+                vec![JsValue::new(length)],
+            ));
         }
 
-        let array =
-            JsObject::from_proto_and_data_with_shared_shape(context.root_shape(), prototype, Array)
-                .upcast();
+        let array = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
+            context.root_shape(),
+            prototype,
+            Array,
+        )
+        .upcast();
 
         // 6. Perform ! OrdinaryDefineOwnProperty(A, "length", PropertyDescriptor { [[Value]]: 𝔽(length), [[Writable]]: true, [[Enumerable]]: false, [[Configurable]]: false }).
         ordinary_define_own_property(
@@ -408,6 +414,7 @@ impl Array {
             .templates()
             .array()
             .create_with_indexed_properties(
+                context.gc_collector(),
                 Array,
                 vec![JsValue::new(length)],
                 IndexedProperties::from_dense_js_value(elements),
@@ -3283,9 +3290,9 @@ impl Array {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-array.prototype-@@unscopables
     /// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/@@unscopables
-    pub(crate) fn unscopables_object() -> JsObject {
+    pub(crate) fn unscopables_object(mc: &boa_gc::MutationContext<'static, '_>) -> JsObject {
         // 1. Let unscopableList be OrdinaryObjectCreate(null).
-        let unscopable_list = JsObject::with_null_proto();
+        let unscopable_list = JsObject::with_null_proto(mc);
         let true_prop = PropertyDescriptor::builder()
             .value(true)
             .writable(true)
@@ -3294,37 +3301,37 @@ impl Array {
         {
             let mut obj = unscopable_list.borrow_mut();
             // 2. Perform ! CreateDataPropertyOrThrow(unscopableList, "at", true).
-            obj.insert(js_string!("at"), true_prop.clone());
+            obj.insert(mc, js_string!("at"), true_prop.clone());
             // 3. Perform ! CreateDataPropertyOrThrow(unscopableList, "copyWithin", true).
-            obj.insert(js_string!("copyWithin"), true_prop.clone());
+            obj.insert(mc, js_string!("copyWithin"), true_prop.clone());
             // 4. Perform ! CreateDataPropertyOrThrow(unscopableList, "entries", true).
-            obj.insert(js_string!("entries"), true_prop.clone());
+            obj.insert(mc, js_string!("entries"), true_prop.clone());
             // 5. Perform ! CreateDataPropertyOrThrow(unscopableList, "fill", true).
-            obj.insert(js_string!("fill"), true_prop.clone());
+            obj.insert(mc, js_string!("fill"), true_prop.clone());
             // 6. Perform ! CreateDataPropertyOrThrow(unscopableList, "find", true).
-            obj.insert(js_string!("find"), true_prop.clone());
+            obj.insert(mc, js_string!("find"), true_prop.clone());
             // 7. Perform ! CreateDataPropertyOrThrow(unscopableList, "findIndex", true).
-            obj.insert(js_string!("findIndex"), true_prop.clone());
+            obj.insert(mc, js_string!("findIndex"), true_prop.clone());
             // 8. Perform ! CreateDataPropertyOrThrow(unscopableList, "findLast", true).
-            obj.insert(js_string!("findLast"), true_prop.clone());
+            obj.insert(mc, js_string!("findLast"), true_prop.clone());
             // 9. Perform ! CreateDataPropertyOrThrow(unscopableList, "findLastIndex", true).
-            obj.insert(js_string!("findLastIndex"), true_prop.clone());
+            obj.insert(mc, js_string!("findLastIndex"), true_prop.clone());
             // 10. Perform ! CreateDataPropertyOrThrow(unscopableList, "flat", true).
-            obj.insert(js_string!("flat"), true_prop.clone());
+            obj.insert(mc, js_string!("flat"), true_prop.clone());
             // 11. Perform ! CreateDataPropertyOrThrow(unscopableList, "flatMap", true).
-            obj.insert(js_string!("flatMap"), true_prop.clone());
+            obj.insert(mc, js_string!("flatMap"), true_prop.clone());
             // 12. Perform ! CreateDataPropertyOrThrow(unscopableList, "includes", true).
-            obj.insert(js_string!("includes"), true_prop.clone());
+            obj.insert(mc, js_string!("includes"), true_prop.clone());
             // 13. Perform ! CreateDataPropertyOrThrow(unscopableList, "keys", true).
-            obj.insert(js_string!("keys"), true_prop.clone());
+            obj.insert(mc, js_string!("keys"), true_prop.clone());
             // 14. Perform ! CreateDataPropertyOrThrow(unscopableList, "toReversed", true).
-            obj.insert(js_string!("toReversed"), true_prop.clone());
+            obj.insert(mc, js_string!("toReversed"), true_prop.clone());
             // 15. Perform ! CreateDataPropertyOrThrow(unscopableList, "toSorted", true).
-            obj.insert(js_string!("toSorted"), true_prop.clone());
+            obj.insert(mc, js_string!("toSorted"), true_prop.clone());
             // 16. Perform ! CreateDataPropertyOrThrow(unscopableList, "toSpliced", true).
-            obj.insert(js_string!("toSpliced"), true_prop.clone());
+            obj.insert(mc, js_string!("toSpliced"), true_prop.clone());
             // 17. Perform ! CreateDataPropertyOrThrow(unscopableList, "values", true).
-            obj.insert(js_string!("values"), true_prop);
+            obj.insert(mc, js_string!("values"), true_prop);
         }
 
         // 13. Return unscopableList.
diff --git a/core/engine/src/builtins/array_buffer/mod.rs b/core/engine/src/builtins/array_buffer/mod.rs
index 5b8c5a1bfa5..3e937776a42 100644
--- a/core/engine/src/builtins/array_buffer/mod.rs
+++ b/core/engine/src/builtins/array_buffer/mod.rs
@@ -327,31 +327,31 @@ impl ArrayBuffer {
 }
 
 impl IntrinsicObject for ArrayBuffer {
-    fn init(realm: &Realm) {
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
         let flag_attributes = Attribute::CONFIGURABLE | Attribute::NON_ENUMERABLE;
 
-        let get_species = BuiltInBuilder::callable(realm, Self::get_species)
+        let get_species = BuiltInBuilder::callable(realm, Self::get_species, mc)
             .name(js_string!("get [Symbol.species]"))
             .build();
 
-        let get_byte_length = BuiltInBuilder::callable(realm, Self::get_byte_length)
+        let get_byte_length = BuiltInBuilder::callable(realm, Self::get_byte_length, mc)
             .name(js_string!("get byteLength"))
             .build();
 
-        let get_resizable = BuiltInBuilder::callable(realm, Self::get_resizable)
+        let get_resizable = BuiltInBuilder::callable(realm, Self::get_resizable, mc)
             .name(js_string!("get resizable"))
             .build();
 
-        let get_max_byte_length = BuiltInBuilder::callable(realm, Self::get_max_byte_length)
+        let get_max_byte_length = BuiltInBuilder::callable(realm, Self::get_max_byte_length, mc)
             .name(js_string!("get maxByteLength"))
             .build();
 
         #[cfg(feature = "experimental")]
-        let get_detached = BuiltInBuilder::callable(realm, Self::get_detached)
+        let get_detached = BuiltInBuilder::callable(realm, Self::get_detached, mc)
             .name(js_string!("get detached"))
             .build();
 
-        let builder = BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        let builder = BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .static_accessor(
                 JsSymbol::species(),
                 Some(get_species),
@@ -848,6 +848,7 @@ impl ArrayBuffer {
             .prototype();
 
         Ok(JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             prototype,
             ArrayBuffer {
@@ -899,6 +900,7 @@ impl ArrayBuffer {
         let block = create_byte_data_block(byte_len, max_byte_len, context)?;
 
         let obj = JsObject::new(
+            context.gc_collector(),
             context.root_shape(),
             prototype,
             Self {
diff --git a/core/engine/src/builtins/array_buffer/shared.rs b/core/engine/src/builtins/array_buffer/shared.rs
index 5c4b30b8482..31f80885850 100644
--- a/core/engine/src/builtins/array_buffer/shared.rs
+++ b/core/engine/src/builtins/array_buffer/shared.rs
@@ -96,26 +96,26 @@ impl SharedArrayBuffer {
 }
 
 impl IntrinsicObject for SharedArrayBuffer {
-    fn init(realm: &Realm) {
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
         let flag_attributes = Attribute::CONFIGURABLE | Attribute::NON_ENUMERABLE;
 
-        let get_species = BuiltInBuilder::callable(realm, Self::get_species)
+        let get_species = BuiltInBuilder::callable(realm, Self::get_species, mc)
             .name(js_string!("get [Symbol.species]"))
             .build();
 
-        let get_byte_length = BuiltInBuilder::callable(realm, Self::get_byte_length)
+        let get_byte_length = BuiltInBuilder::callable(realm, Self::get_byte_length, mc)
             .name(js_string!("get byteLength"))
             .build();
 
-        let get_growable = BuiltInBuilder::callable(realm, Self::get_growable)
+        let get_growable = BuiltInBuilder::callable(realm, Self::get_growable, mc)
             .name(js_string!("get growable"))
             .build();
 
-        let get_max_byte_length = BuiltInBuilder::callable(realm, Self::get_max_byte_length)
+        let get_max_byte_length = BuiltInBuilder::callable(realm, Self::get_max_byte_length, mc)
             .name(js_string!("get maxByteLength"))
             .build();
 
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .static_accessor(
                 JsSymbol::species(),
                 Some(get_species),
@@ -537,6 +537,7 @@ impl SharedArrayBuffer {
         // 10. Else,
         //     a. Set obj.[[ArrayBufferByteLength]] to byteLength.
         let obj = JsObject::new(
+            context.gc_collector(),
             context.root_shape(),
             prototype,
             Self {
diff --git a/core/engine/src/builtins/async_function/mod.rs b/core/engine/src/builtins/async_function/mod.rs
index 783f97c7e77..da47f3e351b 100644
--- a/core/engine/src/builtins/async_function/mod.rs
+++ b/core/engine/src/builtins/async_function/mod.rs
@@ -24,8 +24,8 @@ use super::{BuiltInBuilder, BuiltInConstructor, IntrinsicObject};
 pub struct AsyncFunction;
 
 impl IntrinsicObject for AsyncFunction {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .prototype(realm.intrinsics().constructors().function().constructor())
             .inherits(Some(
                 realm.intrinsics().constructors().function().prototype(),
diff --git a/core/engine/src/builtins/async_generator/mod.rs b/core/engine/src/builtins/async_generator/mod.rs
index c3d99c3187b..298fc9f29c1 100644
--- a/core/engine/src/builtins/async_generator/mod.rs
+++ b/core/engine/src/builtins/async_generator/mod.rs
@@ -70,8 +70,8 @@ pub struct AsyncGenerator {
 }
 
 impl IntrinsicObject for AsyncGenerator {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::with_intrinsic::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::with_intrinsic::<Self>(realm, mc)
             .prototype(
                 realm
                     .intrinsics()
@@ -580,6 +580,7 @@ impl AsyncGenerator {
         // 12. Let onFulfilled be CreateBuiltinFunction(fulfilledClosure, 1, "", « »).
         let on_fulfilled = FunctionObjectBuilder::new(
             context.realm(),
+            context.gc_collector(),
             NativeFunction::from_copy_closure_with_captures(
                 |_this, args, generator, context| {
                     // a. Assert: generator.[[AsyncGeneratorState]] is draining-queue.
@@ -611,6 +612,7 @@ impl AsyncGenerator {
         // 14. Let onRejected be CreateBuiltinFunction(rejectedClosure, 1, "", « »).
         let on_rejected = FunctionObjectBuilder::new(
             context.realm(),
+            context.gc_collector(),
             NativeFunction::from_copy_closure_with_captures(
                 |_this, args, generator, context| {
                     // a. Assert: generator.[[AsyncGeneratorState]] is draining-queue.
diff --git a/core/engine/src/builtins/async_generator_function/mod.rs b/core/engine/src/builtins/async_generator_function/mod.rs
index 5e9eded12fb..97be453d7cd 100644
--- a/core/engine/src/builtins/async_generator_function/mod.rs
+++ b/core/engine/src/builtins/async_generator_function/mod.rs
@@ -24,8 +24,8 @@ use super::{BuiltInBuilder, BuiltInConstructor, IntrinsicObject};
 pub struct AsyncGeneratorFunction;
 
 impl IntrinsicObject for AsyncGeneratorFunction {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .inherits(Some(
                 realm.intrinsics().constructors().function().prototype(),
             ))
diff --git a/core/engine/src/builtins/atomics/mod.rs b/core/engine/src/builtins/atomics/mod.rs
index 43c0c1e7d0a..f19ae8ba98c 100644
--- a/core/engine/src/builtins/atomics/mod.rs
+++ b/core/engine/src/builtins/atomics/mod.rs
@@ -39,8 +39,8 @@ use super::{
 pub(crate) struct Atomics;
 
 impl IntrinsicObject for Atomics {
-    fn init(realm: &Realm) {
-        let builder = BuiltInBuilder::with_intrinsic::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        let builder = BuiltInBuilder::with_intrinsic::<Self>(realm, mc)
             .static_property(
                 JsSymbol::to_string_tag(),
                 Self::NAME,
@@ -494,7 +494,11 @@ impl Atomics {
                 .intrinsics()
                 .templates()
                 .wait_async()
-                .create(OrdinaryObject, vec![is_async.into(), value])
+                .create(
+                    context.gc_collector(),
+                    OrdinaryObject,
+                    vec![is_async.into(), value],
+                )
                 .into())
         } else {
             let result = unsafe {
diff --git a/core/engine/src/builtins/bigint/mod.rs b/core/engine/src/builtins/bigint/mod.rs
index f22f3c8da08..b24d56e1ba5 100644
--- a/core/engine/src/builtins/bigint/mod.rs
+++ b/core/engine/src/builtins/bigint/mod.rs
@@ -37,8 +37,8 @@ mod tests;
 pub struct BigInt;
 
 impl IntrinsicObject for BigInt {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .method(Self::to_string, js_string!("toString"), 0)
             .method(Self::to_locale_string, js_string!("toLocaleString"), 0)
             .method(Self::value_of, js_string!("valueOf"), 0)
diff --git a/core/engine/src/builtins/boolean/mod.rs b/core/engine/src/builtins/boolean/mod.rs
index af79e50b5e7..982646bafb3 100644
--- a/core/engine/src/builtins/boolean/mod.rs
+++ b/core/engine/src/builtins/boolean/mod.rs
@@ -30,8 +30,8 @@ use super::{BuiltInBuilder, BuiltInConstructor, IntrinsicObject};
 pub(crate) struct Boolean;
 
 impl IntrinsicObject for Boolean {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .method(Self::to_string, js_string!("toString"), 0)
             .method(Self::value_of, js_string!("valueOf"), 0)
             .build();
@@ -69,8 +69,12 @@ impl BuiltInConstructor for Boolean {
         }
         let prototype =
             get_prototype_from_constructor(new_target, StandardConstructors::boolean, context)?;
-        let boolean =
-            JsObject::from_proto_and_data_with_shared_shape(context.root_shape(), prototype, data);
+        let boolean = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
+            context.root_shape(),
+            prototype,
+            data,
+        );
 
         Ok(boolean.into())
     }
diff --git a/core/engine/src/builtins/builder.rs b/core/engine/src/builtins/builder.rs
index ded9726ac82..20a4aef5808 100644
--- a/core/engine/src/builtins/builder.rs
+++ b/core/engine/src/builtins/builder.rs
@@ -60,12 +60,13 @@ pub(crate) struct OrdinaryObject;
 
 /// Applies the pending builder data to the object.
 pub(crate) trait ApplyToObject {
-    fn apply_to(self, object: &JsObject);
+    fn apply_to(self, mc: &boa_gc::MutationContext<'static, '_>, object: &JsObject);
 }
 
 impl ApplyToObject for Constructor {
-    fn apply_to(self, object: &JsObject) {
+    fn apply_to(self, mc: &boa_gc::MutationContext<'static, '_>, object: &JsObject) {
         object.insert(
+            mc,
             PROTOTYPE,
             PropertyDescriptor::builder()
                 .value(self.prototype.clone())
@@ -76,8 +77,9 @@ impl ApplyToObject for Constructor {
 
         {
             let mut prototype = self.prototype.borrow_mut();
-            prototype.set_prototype(self.inherits);
+            prototype.set_prototype(mc, self.inherits);
             prototype.insert(
+                mc,
                 CONSTRUCTOR,
                 PropertyDescriptor::builder()
                     .value(object.clone())
@@ -90,15 +92,15 @@ impl ApplyToObject for Constructor {
 }
 
 impl ApplyToObject for ConstructorNoProto {
-    fn apply_to(self, _: &JsObject) {}
+    fn apply_to(self, _: &boa_gc::MutationContext<'static, '_>, _: &JsObject) {}
 }
 
 impl ApplyToObject for OrdinaryFunction {
-    fn apply_to(self, _: &JsObject) {}
+    fn apply_to(self, _: &boa_gc::MutationContext<'static, '_>, _: &JsObject) {}
 }
 
 impl<S: ApplyToObject + IsConstructor> ApplyToObject for Callable<S> {
-    fn apply_to(self, object: &JsObject) {
+    fn apply_to(self, mc: &boa_gc::MutationContext<'static, '_>, object: &JsObject) {
         {
             let mut function = object
                 .downcast_mut::<NativeFunctionObject>()
@@ -108,6 +110,7 @@ impl<S: ApplyToObject + IsConstructor> ApplyToObject for Callable<S> {
             function.realm = Some(self.realm);
         }
         object.insert(
+            mc,
             StaticJsStrings::LENGTH,
             PropertyDescriptor::builder()
                 .value(self.length)
@@ -116,6 +119,7 @@ impl<S: ApplyToObject + IsConstructor> ApplyToObject for Callable<S> {
                 .configurable(true),
         );
         object.insert(
+            mc,
             js_string!("name"),
             PropertyDescriptor::builder()
                 .value(self.name)
@@ -124,22 +128,22 @@ impl<S: ApplyToObject + IsConstructor> ApplyToObject for Callable<S> {
                 .configurable(true),
         );
 
-        self.kind.apply_to(object);
+        self.kind.apply_to(mc, object);
     }
 }
 
 impl ApplyToObject for OrdinaryObject {
-    fn apply_to(self, _: &JsObject) {}
+    fn apply_to(self, _: &boa_gc::MutationContext<'static, '_>, _: &JsObject) {}
 }
 
 /// Builder for creating built-in objects, like `Array`.
 ///
 /// The marker `ObjectType` restricts the methods that can be called depending on the
 /// type of object that is being constructed.
-#[derive(Debug)]
 #[must_use = "You need to call the `build` method in order for this to correctly assign the inner data"]
 pub(crate) struct BuiltInBuilder<'ctx, Kind> {
     realm: &'ctx Realm,
+    mc: &'ctx boa_gc::MutationContext<'static, 'ctx>,
     object: JsObject,
     kind: Kind,
     prototype: JsObject,
@@ -148,9 +152,11 @@ pub(crate) struct BuiltInBuilder<'ctx, Kind> {
 impl<'ctx> BuiltInBuilder<'ctx, OrdinaryObject> {
     pub(crate) fn with_intrinsic<I: IntrinsicObject>(
         realm: &'ctx Realm,
+        mc: &'ctx boa_gc::MutationContext<'static, 'ctx>,
     ) -> BuiltInBuilder<'ctx, OrdinaryObject> {
         BuiltInBuilder {
             realm,
+            mc,
             object: I::get(realm.intrinsics()),
             kind: OrdinaryObject,
             prototype: realm.intrinsics().constructors().object().prototype(),
@@ -160,6 +166,7 @@ impl<'ctx> BuiltInBuilder<'ctx, OrdinaryObject> {
 
 pub(crate) struct BuiltInConstructorWithPrototype<'ctx> {
     realm: &'ctx Realm,
+    mc: &'ctx boa_gc::MutationContext<'static, 'ctx>,
     function: NativeFunctionPointer,
     name: JsString,
     length: usize,
@@ -222,7 +229,7 @@ impl BuiltInConstructorWithPrototype<'_> {
         B: Into<FunctionBinding>,
     {
         let binding = binding.into();
-        let function = BuiltInBuilder::callable(self.realm, function)
+        let function = BuiltInBuilder::callable(self.realm, function, self.mc)
             .name(binding.name)
             .length(length)
             .build();
@@ -302,7 +309,7 @@ impl BuiltInConstructorWithPrototype<'_> {
         B: Into<FunctionBinding>,
     {
         let binding = binding.into();
-        let function = BuiltInBuilder::callable(self.realm, function)
+        let function = BuiltInBuilder::callable(self.realm, function, self.mc)
             .name(binding.name)
             .length(length)
             .build();
@@ -490,6 +497,7 @@ impl BuiltInConstructorWithPrototype<'_> {
 
 pub(crate) struct BuiltInCallable<'ctx> {
     realm: &'ctx Realm,
+    mc: &'ctx boa_gc::MutationContext<'static, 'ctx>,
     function: NativeFunctionPointer,
     name: JsString,
     length: usize,
@@ -515,6 +523,7 @@ impl BuiltInCallable<'_> {
 
     pub(crate) fn build(self) -> JsFunction {
         let object = self.realm.intrinsics().templates().function().create(
+            self.mc,
             NativeFunctionObject {
                 f: NativeFunction::from_fn_ptr(self.function),
                 name: self.name.clone(),
@@ -532,9 +541,11 @@ impl<'ctx> BuiltInBuilder<'ctx, OrdinaryObject> {
     pub(crate) fn callable(
         realm: &'ctx Realm,
         function: NativeFunctionPointer,
+        mc: &'ctx boa_gc::MutationContext<'static, 'ctx>,
     ) -> BuiltInCallable<'ctx> {
         BuiltInCallable {
             realm,
+            mc,
             function,
             length: 0,
             name: js_string!(),
@@ -544,9 +555,11 @@ impl<'ctx> BuiltInBuilder<'ctx, OrdinaryObject> {
     pub(crate) fn callable_with_intrinsic<I: IntrinsicObject>(
         realm: &'ctx Realm,
         function: NativeFunctionPointer,
+        mc: &'ctx boa_gc::MutationContext<'static, 'ctx>,
     ) -> BuiltInBuilder<'ctx, Callable<OrdinaryFunction>> {
         BuiltInBuilder {
             realm,
+            mc,
             object: I::get(realm.intrinsics()),
             kind: Callable {
                 function,
@@ -563,9 +576,11 @@ impl<'ctx> BuiltInBuilder<'ctx, OrdinaryObject> {
         realm: &'ctx Realm,
         object: JsObject,
         function: NativeFunctionPointer,
+        mc: &'ctx boa_gc::MutationContext<'static, 'ctx>,
     ) -> BuiltInBuilder<'ctx, Callable<OrdinaryFunction>> {
         BuiltInBuilder {
             realm,
+            mc,
             object,
             kind: Callable {
                 function,
@@ -586,10 +601,12 @@ impl<'ctx> BuiltInBuilder<'ctx, Callable<Constructor>> {
     /// (less reallocations).
     pub(crate) fn from_standard_constructor<SC: BuiltInConstructor>(
         realm: &'ctx Realm,
+        mc: &'ctx boa_gc::MutationContext<'static, 'ctx>,
     ) -> BuiltInConstructorWithPrototype<'ctx> {
         let constructor = SC::STANDARD_CONSTRUCTOR(realm.intrinsics().constructors());
         BuiltInConstructorWithPrototype {
             realm,
+            mc,
             function: SC::constructor,
             name: js_string!(SC::NAME),
             length: SC::CONSTRUCTOR_ARGUMENTS,
@@ -634,12 +651,13 @@ impl<T> BuiltInBuilder<'_, T> {
         B: Into<FunctionBinding>,
     {
         let binding = binding.into();
-        let function = BuiltInBuilder::callable(self.realm, function)
+        let function = BuiltInBuilder::callable(self.realm, function, self.mc)
             .name(binding.name)
             .length(length)
             .build();
 
         self.object.insert(
+            self.mc,
             binding.binding,
             PropertyDescriptor::builder()
                 .value(function)
@@ -661,7 +679,7 @@ impl<T> BuiltInBuilder<'_, T> {
             .writable(attribute.writable())
             .enumerable(attribute.enumerable())
             .configurable(attribute.configurable());
-        self.object.insert(key, property);
+        self.object.insert(self.mc, key, property);
         self
     }
 
@@ -690,7 +708,7 @@ impl<T> BuiltInBuilder<'_, T> {
 
         let key = key.into();
 
-        self.object.insert(key, property);
+        self.object.insert(self.mc, key, property);
 
         self
     }
@@ -726,9 +744,9 @@ impl<FnTyp> BuiltInBuilder<'_, Callable<FnTyp>> {
 impl BuiltInBuilder<'_, OrdinaryObject> {
     /// Build the builtin object.
     pub(crate) fn build(self) -> JsObject {
-        self.kind.apply_to(&self.object);
+        self.kind.apply_to(self.mc, &self.object);
 
-        self.object.set_prototype(Some(self.prototype));
+        self.object.set_prototype(self.mc, Some(self.prototype));
 
         self.object
     }
@@ -737,9 +755,9 @@ impl BuiltInBuilder<'_, OrdinaryObject> {
 impl<FnTyp: ApplyToObject + IsConstructor> BuiltInBuilder<'_, Callable<FnTyp>> {
     /// Build the builtin callable.
     pub(crate) fn build(self) -> JsFunction {
-        self.kind.apply_to(&self.object);
+        self.kind.apply_to(self.mc, &self.object);
 
-        self.object.set_prototype(Some(self.prototype));
+        self.object.set_prototype(self.mc, Some(self.prototype));
 
         JsFunction::from_object_unchecked(self.object)
     }
diff --git a/core/engine/src/builtins/dataview/mod.rs b/core/engine/src/builtins/dataview/mod.rs
index 36b2de954ab..e699062ddc6 100644
--- a/core/engine/src/builtins/dataview/mod.rs
+++ b/core/engine/src/builtins/dataview/mod.rs
@@ -94,22 +94,22 @@ impl DataView {
 }
 
 impl IntrinsicObject for DataView {
-    fn init(realm: &Realm) {
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
         let flag_attributes = Attribute::CONFIGURABLE | Attribute::NON_ENUMERABLE;
 
-        let get_buffer = BuiltInBuilder::callable(realm, Self::get_buffer)
+        let get_buffer = BuiltInBuilder::callable(realm, Self::get_buffer, mc)
             .name(js_string!("get buffer"))
             .build();
 
-        let get_byte_length = BuiltInBuilder::callable(realm, Self::get_byte_length)
+        let get_byte_length = BuiltInBuilder::callable(realm, Self::get_byte_length, mc)
             .name(js_string!("get byteLength"))
             .build();
 
-        let get_byte_offset = BuiltInBuilder::callable(realm, Self::get_byte_offset)
+        let get_byte_offset = BuiltInBuilder::callable(realm, Self::get_byte_offset, mc)
             .name(js_string!("get byteOffset"))
             .build();
 
-        let builder = BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        let builder = BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .accessor(
                 js_string!("buffer"),
                 Some(get_buffer),
@@ -295,6 +295,7 @@ impl BuiltInConstructor for DataView {
         }
 
         let obj = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             prototype,
             Self {
diff --git a/core/engine/src/builtins/date/mod.rs b/core/engine/src/builtins/date/mod.rs
index 0c82b5b570f..9b94d563960 100644
--- a/core/engine/src/builtins/date/mod.rs
+++ b/core/engine/src/builtins/date/mod.rs
@@ -83,18 +83,18 @@ impl Date {
 }
 
 impl IntrinsicObject for Date {
-    fn init(realm: &Realm) {
-        let to_utc_string = BuiltInBuilder::callable(realm, Self::to_utc_string)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        let to_utc_string = BuiltInBuilder::callable(realm, Self::to_utc_string, mc)
             .name(js_string!("toUTCString"))
             .length(0)
             .build();
 
-        let to_primitive = BuiltInBuilder::callable(realm, Self::to_primitive)
+        let to_primitive = BuiltInBuilder::callable(realm, Self::to_primitive, mc)
             .name(js_string!("[Symbol.toPrimitive]"))
             .length(1)
             .build();
 
-        let builder = BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        let builder = BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .static_method(Self::now, js_string!("now"), 0)
             .static_method(Self::parse, js_string!("parse"), 1)
             .static_method(Self::utc, js_string!("UTC"), 7)
@@ -335,8 +335,12 @@ impl BuiltInConstructor for Date {
             get_prototype_from_constructor(new_target, StandardConstructors::date, context)?;
 
         // 7. Set O.[[DateValue]] to dv.
-        let obj =
-            JsObject::from_proto_and_data_with_shared_shape(context.root_shape(), prototype, dv);
+        let obj = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
+            context.root_shape(),
+            prototype,
+            dv,
+        );
 
         // 8. Return O.
         Ok(obj.into())
diff --git a/core/engine/src/builtins/error/aggregate.rs b/core/engine/src/builtins/error/aggregate.rs
index 186f6aede5a..ac0d3651731 100644
--- a/core/engine/src/builtins/error/aggregate.rs
+++ b/core/engine/src/builtins/error/aggregate.rs
@@ -27,9 +27,9 @@ use super::{Error, ErrorKind};
 pub(crate) struct AggregateError;
 
 impl IntrinsicObject for AggregateError {
-    fn init(realm: &Realm) {
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
         let attribute = Attribute::WRITABLE | Attribute::NON_ENUMERABLE | Attribute::CONFIGURABLE;
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .prototype(realm.intrinsics().constructors().error().constructor())
             .inherits(Some(realm.intrinsics().constructors().error().prototype()))
             .property(js_string!("name"), Self::NAME, attribute)
@@ -86,6 +86,7 @@ impl BuiltInConstructor for AggregateError {
             context,
         )?;
         let o = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             prototype,
             Error::with_caller_position(ErrorKind::Aggregate, context),
diff --git a/core/engine/src/builtins/error/eval.rs b/core/engine/src/builtins/error/eval.rs
index aa762a4b139..2de873ce3be 100644
--- a/core/engine/src/builtins/error/eval.rs
+++ b/core/engine/src/builtins/error/eval.rs
@@ -29,9 +29,9 @@ use super::{Error, ErrorKind};
 pub(crate) struct EvalError;
 
 impl IntrinsicObject for EvalError {
-    fn init(realm: &Realm) {
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
         let attribute = Attribute::WRITABLE | Attribute::NON_ENUMERABLE | Attribute::CONFIGURABLE;
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .prototype(realm.intrinsics().constructors().error().constructor())
             .inherits(Some(realm.intrinsics().constructors().error().prototype()))
             .property(js_string!("name"), Self::NAME, attribute)
diff --git a/core/engine/src/builtins/error/mod.rs b/core/engine/src/builtins/error/mod.rs
index 44c8f561b9b..ada42af50cd 100644
--- a/core/engine/src/builtins/error/mod.rs
+++ b/core/engine/src/builtins/error/mod.rs
@@ -179,20 +179,20 @@ impl Error {
 }
 
 impl IntrinsicObject for Error {
-    fn init(realm: &Realm) {
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
         let property_attribute =
             Attribute::WRITABLE | Attribute::NON_ENUMERABLE | Attribute::CONFIGURABLE;
         let accessor_attribute = Attribute::NON_ENUMERABLE | Attribute::CONFIGURABLE;
 
-        let get_stack = BuiltInBuilder::callable(realm, Self::get_stack)
+        let get_stack = BuiltInBuilder::callable(realm, Self::get_stack, mc)
             .name(js_string!("get stack"))
             .build();
 
-        let set_stack = BuiltInBuilder::callable(realm, Self::set_stack)
+        let set_stack = BuiltInBuilder::callable(realm, Self::set_stack, mc)
             .name(js_string!("set stack"))
             .build();
 
-        let builder = BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        let builder = BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .property(js_string!("name"), Self::NAME, property_attribute)
             .property(js_string!("message"), js_string!(), property_attribute)
             .method(Self::to_string, js_string!("toString"), 0)
@@ -248,6 +248,7 @@ impl BuiltInConstructor for Error {
         let prototype =
             get_prototype_from_constructor(new_target, StandardConstructors::error, context)?;
         let o = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             prototype,
             Error::with_caller_position(ErrorKind::Error, context),
@@ -468,6 +469,7 @@ impl Error {
 
         let prototype = get_prototype_from_constructor(new_target, constructor_fn, context)?;
         let o = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             prototype,
             Error::with_caller_position(error_kind, context),
diff --git a/core/engine/src/builtins/error/range.rs b/core/engine/src/builtins/error/range.rs
index c31abc2727c..0ff83aed0ad 100644
--- a/core/engine/src/builtins/error/range.rs
+++ b/core/engine/src/builtins/error/range.rs
@@ -27,9 +27,9 @@ use super::{Error, ErrorKind};
 pub(crate) struct RangeError;
 
 impl IntrinsicObject for RangeError {
-    fn init(realm: &Realm) {
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
         let attribute = Attribute::WRITABLE | Attribute::NON_ENUMERABLE | Attribute::CONFIGURABLE;
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .prototype(realm.intrinsics().constructors().error().constructor())
             .inherits(Some(realm.intrinsics().constructors().error().prototype()))
             .property(js_string!("name"), Self::NAME, attribute)
diff --git a/core/engine/src/builtins/error/reference.rs b/core/engine/src/builtins/error/reference.rs
index 310346e2ce5..be892436ab1 100644
--- a/core/engine/src/builtins/error/reference.rs
+++ b/core/engine/src/builtins/error/reference.rs
@@ -26,9 +26,9 @@ use super::{Error, ErrorKind};
 pub(crate) struct ReferenceError;
 
 impl IntrinsicObject for ReferenceError {
-    fn init(realm: &Realm) {
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
         let attribute = Attribute::WRITABLE | Attribute::NON_ENUMERABLE | Attribute::CONFIGURABLE;
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .prototype(realm.intrinsics().constructors().error().constructor())
             .inherits(Some(realm.intrinsics().constructors().error().prototype()))
             .property(js_string!("name"), Self::NAME, attribute)
diff --git a/core/engine/src/builtins/error/syntax.rs b/core/engine/src/builtins/error/syntax.rs
index 1954b65a21c..2ede57d5e1c 100644
--- a/core/engine/src/builtins/error/syntax.rs
+++ b/core/engine/src/builtins/error/syntax.rs
@@ -29,9 +29,9 @@ use super::{Error, ErrorKind};
 pub(crate) struct SyntaxError;
 
 impl IntrinsicObject for SyntaxError {
-    fn init(realm: &Realm) {
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
         let attribute = Attribute::WRITABLE | Attribute::NON_ENUMERABLE | Attribute::CONFIGURABLE;
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .prototype(realm.intrinsics().constructors().error().constructor())
             .inherits(Some(realm.intrinsics().constructors().error().prototype()))
             .property(js_string!("name"), Self::NAME, attribute)
diff --git a/core/engine/src/builtins/error/type.rs b/core/engine/src/builtins/error/type.rs
index e783ecdc94f..a3f06151cbb 100644
--- a/core/engine/src/builtins/error/type.rs
+++ b/core/engine/src/builtins/error/type.rs
@@ -35,9 +35,9 @@ use super::{Error, ErrorKind};
 pub(crate) struct TypeError;
 
 impl IntrinsicObject for TypeError {
-    fn init(realm: &Realm) {
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
         let attribute = Attribute::WRITABLE | Attribute::NON_ENUMERABLE | Attribute::CONFIGURABLE;
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .prototype(realm.intrinsics().constructors().error().constructor())
             .inherits(Some(realm.intrinsics().constructors().error().prototype()))
             .property(js_string!("name"), Self::NAME, attribute)
@@ -82,8 +82,8 @@ impl BuiltInConstructor for TypeError {
 pub(crate) struct ThrowTypeError;
 
 impl IntrinsicObject for ThrowTypeError {
-    fn init(realm: &Realm) {
-        let obj = BuiltInBuilder::with_intrinsic::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        let obj = BuiltInBuilder::with_intrinsic::<Self>(realm, mc)
             .prototype(realm.intrinsics().constructors().function().prototype())
             .static_property(StaticJsStrings::LENGTH, 0, Attribute::empty())
             .static_property(js_string!("name"), js_string!(), Attribute::empty())
diff --git a/core/engine/src/builtins/error/uri.rs b/core/engine/src/builtins/error/uri.rs
index 0da05778709..08f970c9be7 100644
--- a/core/engine/src/builtins/error/uri.rs
+++ b/core/engine/src/builtins/error/uri.rs
@@ -28,9 +28,9 @@ use super::{Error, ErrorKind};
 pub(crate) struct UriError;
 
 impl IntrinsicObject for UriError {
-    fn init(realm: &Realm) {
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
         let attribute = Attribute::WRITABLE | Attribute::NON_ENUMERABLE | Attribute::CONFIGURABLE;
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .prototype(realm.intrinsics().constructors().error().constructor())
             .inherits(Some(realm.intrinsics().constructors().error().prototype()))
             .property(js_string!("name"), Self::NAME, attribute)
diff --git a/core/engine/src/builtins/escape/mod.rs b/core/engine/src/builtins/escape/mod.rs
index cc6bd6aa67d..937867673ab 100644
--- a/core/engine/src/builtins/escape/mod.rs
+++ b/core/engine/src/builtins/escape/mod.rs
@@ -22,8 +22,8 @@ use super::{BuiltInBuilder, BuiltInObject, IntrinsicObject};
 pub(crate) struct Escape;
 
 impl IntrinsicObject for Escape {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::callable_with_intrinsic::<Self>(realm, escape)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::callable_with_intrinsic::<Self>(realm, escape, mc)
             .name(Self::NAME)
             .length(1)
             .build();
@@ -94,8 +94,8 @@ fn escape(_: &JsValue, args: &[JsValue], context: &mut Context) -> JsResult<JsVa
 pub(crate) struct Unescape;
 
 impl IntrinsicObject for Unescape {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::callable_with_intrinsic::<Self>(realm, unescape)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::callable_with_intrinsic::<Self>(realm, unescape, mc)
             .name(Self::NAME)
             .length(1)
             .build();
diff --git a/core/engine/src/builtins/eval/mod.rs b/core/engine/src/builtins/eval/mod.rs
index 7d6cf4cd0cd..764c73cbf6e 100644
--- a/core/engine/src/builtins/eval/mod.rs
+++ b/core/engine/src/builtins/eval/mod.rs
@@ -36,8 +36,8 @@ use super::{BuiltInBuilder, IntrinsicObject};
 pub(crate) struct Eval;
 
 impl IntrinsicObject for Eval {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::callable_with_intrinsic::<Self>(realm, Self::eval)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::callable_with_intrinsic::<Self>(realm, Self::eval, mc)
             .name(Self::NAME)
             .length(1)
             .build();
diff --git a/core/engine/src/builtins/finalization_registry/mod.rs b/core/engine/src/builtins/finalization_registry/mod.rs
index 3252ed47984..76899e0256a 100644
--- a/core/engine/src/builtins/finalization_registry/mod.rs
+++ b/core/engine/src/builtins/finalization_registry/mod.rs
@@ -74,8 +74,8 @@ impl IntrinsicObject for FinalizationRegistry {
         Self::STANDARD_CONSTRUCTOR(intrinsics.constructors()).constructor()
     }
 
-    fn init(realm: &Realm) {
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .property(
                 JsSymbol::to_string_tag(),
                 js_string!("FinalizationRegistry"),
@@ -149,6 +149,7 @@ impl BuiltInConstructor for FinalizationRegistry {
         let (sender, receiver) = async_channel::bounded(1);
 
         let registry = JsObject::new_unique(
+            context.gc_collector(),
             prototype,
             FinalizationRegistry {
                 realm,
diff --git a/core/engine/src/builtins/function/arguments.rs b/core/engine/src/builtins/function/arguments.rs
index ab339f96d07..36670bae84d 100644
--- a/core/engine/src/builtins/function/arguments.rs
+++ b/core/engine/src/builtins/function/arguments.rs
@@ -47,6 +47,7 @@ impl UnmappedArguments {
             .templates()
             .unmapped_arguments()
             .create(
+                context.gc_collector(),
                 Self,
                 vec![
                     // 4. Perform DefinePropertyOrThrow(obj, "length", PropertyDescriptor { [[Value]]: 𝔽(len),
@@ -244,6 +245,7 @@ impl MappedArguments {
 
         // 11. Set obj.[[ParameterMap]] to map.
         let obj = context.intrinsics().templates().mapped_arguments().create(
+            context.gc_collector(),
             map,
             vec![
                 // 16. Perform ! DefinePropertyOrThrow(obj, "length", PropertyDescriptor { [[Value]]: 𝔽(len),
diff --git a/core/engine/src/builtins/function/bound.rs b/core/engine/src/builtins/function/bound.rs
index f0331bb209b..c9ea75acb95 100644
--- a/core/engine/src/builtins/function/bound.rs
+++ b/core/engine/src/builtins/function/bound.rs
@@ -66,6 +66,7 @@ impl BoundFunction {
         // 9. Set obj.[[BoundArguments]] to boundArgs.
         // 10. Return obj.
         Ok(JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             proto,
             Self {
diff --git a/core/engine/src/builtins/function/mod.rs b/core/engine/src/builtins/function/mod.rs
index b5279c480d8..800de70a02a 100644
--- a/core/engine/src/builtins/function/mod.rs
+++ b/core/engine/src/builtins/function/mod.rs
@@ -308,15 +308,15 @@ impl OrdinaryFunction {
 pub struct BuiltInFunctionObject;
 
 impl IntrinsicObject for BuiltInFunctionObject {
-    fn init(realm: &Realm) {
-        let has_instance = BuiltInBuilder::callable(realm, Self::has_instance)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        let has_instance = BuiltInBuilder::callable(realm, Self::has_instance, mc)
             .name(js_string!("[Symbol.hasInstance]"))
             .length(1)
             .build();
 
         let throw_type_error = realm.intrinsics().objects().throw_type_error();
 
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .method(Self::apply, js_string!("apply"), 2)
             .method(Self::bind, js_string!("bind"), 1)
             .method(Self::call, js_string!("call"), 1)
@@ -338,12 +338,15 @@ impl IntrinsicObject for BuiltInFunctionObject {
 
         let prototype = realm.intrinsics().constructors().function().prototype();
 
-        BuiltInBuilder::callable_with_object(realm, prototype.clone(), Self::prototype)
+        BuiltInBuilder::callable_with_object(realm, prototype.clone(), Self::prototype, mc)
             .name(js_string!())
             .length(0)
             .build();
 
-        prototype.set_prototype(Some(realm.intrinsics().constructors().object().prototype()));
+        prototype.set_prototype(
+            mc,
+            Some(realm.intrinsics().constructors().object().prototype()),
+        );
     }
 
     fn get(intrinsics: &Intrinsics) -> JsObject {
@@ -1144,6 +1147,7 @@ fn function_construct(
         let prototype =
             get_prototype_from_constructor(&new_target, StandardConstructors::object, context)?;
         let this = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             prototype,
             OrdinaryObject,
diff --git a/core/engine/src/builtins/function/tests.rs b/core/engine/src/builtins/function/tests.rs
index 7200a610e3c..bb63f86efe7 100644
--- a/core/engine/src/builtins/function/tests.rs
+++ b/core/engine/src/builtins/function/tests.rs
@@ -133,7 +133,7 @@ fn closure_capture_clone() {
     run_test_actions([
         TestAction::inspect_context(|ctx| {
             let string = js_string!("Hello");
-            let object = JsObject::with_object_proto(ctx.intrinsics());
+            let object = JsObject::with_object_proto(ctx.gc_collector(), ctx.intrinsics());
             object
                 .define_property_or_throw(
                     js_string!("key"),
@@ -148,6 +148,7 @@ fn closure_capture_clone() {
 
             let func = FunctionObjectBuilder::new(
                 ctx.realm(),
+                ctx.gc_collector(),
                 NativeFunction::from_copy_closure_with_captures(
                     |_, _, captures, context| {
                         let (string, object) = &captures;
diff --git a/core/engine/src/builtins/generator/mod.rs b/core/engine/src/builtins/generator/mod.rs
index 17e60e63aec..9acf67076b0 100644
--- a/core/engine/src/builtins/generator/mod.rs
+++ b/core/engine/src/builtins/generator/mod.rs
@@ -154,8 +154,8 @@ pub struct Generator {
 }
 
 impl IntrinsicObject for Generator {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::with_intrinsic::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::with_intrinsic::<Self>(realm, mc)
             .prototype(realm.intrinsics().constructors().iterator().prototype())
             .static_method(Self::next, js_string!("next"), 1)
             .static_method(Self::r#return, js_string!("return"), 1)
diff --git a/core/engine/src/builtins/generator_function/mod.rs b/core/engine/src/builtins/generator_function/mod.rs
index 1e328772a09..04f8632e4d8 100644
--- a/core/engine/src/builtins/generator_function/mod.rs
+++ b/core/engine/src/builtins/generator_function/mod.rs
@@ -29,8 +29,8 @@ use super::{BuiltInBuilder, BuiltInConstructor, IntrinsicObject};
 pub struct GeneratorFunction;
 
 impl IntrinsicObject for GeneratorFunction {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .inherits(Some(
                 realm.intrinsics().constructors().function().prototype(),
             ))
diff --git a/core/engine/src/builtins/intl/collator/mod.rs b/core/engine/src/builtins/intl/collator/mod.rs
index 00eb1eb84ea..bdf8ceea4be 100644
--- a/core/engine/src/builtins/intl/collator/mod.rs
+++ b/core/engine/src/builtins/intl/collator/mod.rs
@@ -69,12 +69,12 @@ impl Service for Collator {
 }
 
 impl IntrinsicObject for Collator {
-    fn init(realm: &Realm) {
-        let compare = BuiltInBuilder::callable(realm, Self::compare)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        let compare = BuiltInBuilder::callable(realm, Self::compare, mc)
             .name(js_string!("get compare"))
             .build();
 
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .static_method(
                 Self::supported_locales_of,
                 js_string!("supportedLocalesOf"),
@@ -274,6 +274,7 @@ impl BuiltInConstructor for Collator {
         let prototype =
             get_prototype_from_constructor(new_target, StandardConstructors::collator, context)?;
         let collator = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             prototype,
             Self {
@@ -354,6 +355,7 @@ impl Collator {
         } else {
             let bound_compare = FunctionObjectBuilder::new(
                 context.realm(),
+                context.gc_collector(),
                 // 10.3.3.1. Collator Compare Functions
                 // https://tc39.es/ecma402/#sec-collator-compare-functions
                 NativeFunction::from_copy_closure_with_captures(
@@ -423,11 +425,11 @@ impl Collator {
             })?;
 
         // 3. Let options be OrdinaryObjectCreate(%Object.prototype%).
-        let options = context
-            .intrinsics()
-            .templates()
-            .ordinary_object()
-            .create(OrdinaryObject, vec![]);
+        let options = context.intrinsics().templates().ordinary_object().create(
+            context.gc_collector(),
+            OrdinaryObject,
+            vec![],
+        );
 
         // 4. For each row of Table 4, except the header row, in table order, do
         //     a. Let p be the Property value of the current row.
diff --git a/core/engine/src/builtins/intl/date_time_format/mod.rs b/core/engine/src/builtins/intl/date_time_format/mod.rs
index b888eebbe21..0100ad0ab41 100644
--- a/core/engine/src/builtins/intl/date_time_format/mod.rs
+++ b/core/engine/src/builtins/intl/date_time_format/mod.rs
@@ -101,13 +101,13 @@ impl Service for DateTimeFormat {
 }
 
 impl IntrinsicObject for DateTimeFormat {
-    fn init(realm: &Realm) {
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
         use crate::JsSymbol;
-        let get_format = BuiltInBuilder::callable(realm, Self::get_format)
+        let get_format = BuiltInBuilder::callable(realm, Self::get_format, mc)
             .name(js_string!("get format"))
             .build();
 
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .static_method(
                 Self::supported_locales_of,
                 js_string!("supportedLocalesOf"),
@@ -189,7 +189,8 @@ impl BuiltInConstructor for DateTimeFormat {
             StandardConstructors::date_time_format,
             context,
         )?;
-        let date_time_format = JsObject::from_proto_and_data(prototype, dtf);
+        let date_time_format =
+            JsObject::from_proto_and_data(context.gc_collector(), prototype, dtf);
 
         // 3. If the implementation supports the normative optional constructor mode of 4.3 Note 1, then
         //     a. Let this be the this value.
@@ -259,6 +260,7 @@ impl DateTimeFormat {
             // a. Let F be a new built-in function object as defined in DateTime Format Functions (11.5.4).
             let bound_format = FunctionObjectBuilder::new(
                 context.realm(),
+                context.gc_collector(),
                 NativeFunction::from_copy_closure_with_captures(
                     |_, args, dtf, context| {
                         // 1. Let dtf be F.[[DateTimeFormat]].
diff --git a/core/engine/src/builtins/intl/list_format/mod.rs b/core/engine/src/builtins/intl/list_format/mod.rs
index 403fca045e6..4c9f79b0d9e 100644
--- a/core/engine/src/builtins/intl/list_format/mod.rs
+++ b/core/engine/src/builtins/intl/list_format/mod.rs
@@ -53,8 +53,8 @@ impl Service for ListFormat {
 }
 
 impl IntrinsicObject for ListFormat {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .static_method(
                 Self::supported_locales_of,
                 js_string!("supportedLocalesOf"),
@@ -116,7 +116,7 @@ impl BuiltInConstructor for ListFormat {
         let requested_locales = canonicalize_locale_list(locales, context)?;
 
         // 4. Set options to ? GetOptionsObject(options).
-        let options = get_options_object(options)?;
+        let options = get_options_object(options, context.gc_collector())?;
 
         // 5. Let opt be a new Record.
         // 6. Let matcher be ? GetOption(options, "localeMatcher", string, « "lookup", "best fit" », "best fit").
@@ -173,6 +173,7 @@ impl BuiltInConstructor for ListFormat {
         let prototype =
             get_prototype_from_constructor(new_target, StandardConstructors::list_format, context)?;
         let list_format = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             prototype,
             Self {
@@ -380,11 +381,11 @@ impl ListFormat {
         // 4. For each Record { [[Type]], [[Value]] } part in parts, do
         for (n, part) in parts.0.into_iter().enumerate() {
             // a. Let O be OrdinaryObjectCreate(%Object.prototype%).
-            let o = context
-                .intrinsics()
-                .templates()
-                .ordinary_object()
-                .create(OrdinaryObject, vec![]);
+            let o = context.intrinsics().templates().ordinary_object().create(
+                context.gc_collector(),
+                OrdinaryObject,
+                vec![],
+            );
 
             // b. Perform ! CreateDataPropertyOrThrow(O, "type", part.[[Type]]).
             o.create_data_property_or_throw(js_string!("type"), js_string!(part.typ()), context)
@@ -429,11 +430,11 @@ impl ListFormat {
             })?;
 
         // 3. Let options be OrdinaryObjectCreate(%Object.prototype%).
-        let options = context
-            .intrinsics()
-            .templates()
-            .ordinary_object()
-            .create(OrdinaryObject, vec![]);
+        let options = context.intrinsics().templates().ordinary_object().create(
+            context.gc_collector(),
+            OrdinaryObject,
+            vec![],
+        );
 
         // 4. For each row of Table 11, except the header row, in table order, do
         //     a. Let p be the Property value of the current row.
diff --git a/core/engine/src/builtins/intl/locale/mod.rs b/core/engine/src/builtins/intl/locale/mod.rs
index 949f5b094ce..1f1d540e6ff 100644
--- a/core/engine/src/builtins/intl/locale/mod.rs
+++ b/core/engine/src/builtins/intl/locale/mod.rs
@@ -29,52 +29,52 @@ use super::options::coerce_options_to_object;
 pub(crate) struct Locale;
 
 impl IntrinsicObject for Locale {
-    fn init(realm: &Realm) {
-        let base_name = BuiltInBuilder::callable(realm, Self::base_name)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        let base_name = BuiltInBuilder::callable(realm, Self::base_name, mc)
             .name(js_string!("get baseName"))
             .build();
 
-        let calendar = BuiltInBuilder::callable(realm, Self::calendar)
+        let calendar = BuiltInBuilder::callable(realm, Self::calendar, mc)
             .name(js_string!("get calendar"))
             .build();
 
-        let case_first = BuiltInBuilder::callable(realm, Self::case_first)
+        let case_first = BuiltInBuilder::callable(realm, Self::case_first, mc)
             .name(js_string!("get caseFirst"))
             .build();
 
-        let collation = BuiltInBuilder::callable(realm, Self::collation)
+        let collation = BuiltInBuilder::callable(realm, Self::collation, mc)
             .name(js_string!("get collation"))
             .build();
 
-        let hour_cycle = BuiltInBuilder::callable(realm, Self::hour_cycle)
+        let hour_cycle = BuiltInBuilder::callable(realm, Self::hour_cycle, mc)
             .name(js_string!("get hourCycle"))
             .build();
 
-        let numeric = BuiltInBuilder::callable(realm, Self::numeric)
+        let numeric = BuiltInBuilder::callable(realm, Self::numeric, mc)
             .name(js_string!("get numeric"))
             .build();
 
-        let numbering_system = BuiltInBuilder::callable(realm, Self::numbering_system)
+        let numbering_system = BuiltInBuilder::callable(realm, Self::numbering_system, mc)
             .name(js_string!("get numberingSystem"))
             .build();
 
-        let language = BuiltInBuilder::callable(realm, Self::language)
+        let language = BuiltInBuilder::callable(realm, Self::language, mc)
             .name(js_string!("get language"))
             .build();
 
-        let script = BuiltInBuilder::callable(realm, Self::script)
+        let script = BuiltInBuilder::callable(realm, Self::script, mc)
             .name(js_string!("get script"))
             .build();
 
-        let region = BuiltInBuilder::callable(realm, Self::region)
+        let region = BuiltInBuilder::callable(realm, Self::region, mc)
             .name(js_string!("get region"))
             .build();
 
-        let variants = BuiltInBuilder::callable(realm, Self::variants)
+        let variants = BuiltInBuilder::callable(realm, Self::variants, mc)
             .name(js_string!("get variants"))
             .build();
 
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .property(
                 JsSymbol::to_string_tag(),
                 js_string!("Intl.Locale"),
@@ -325,8 +325,12 @@ impl BuiltInConstructor for Locale {
             .locale_canonicalizer()?
             .canonicalize(&mut tag);
 
-        let locale =
-            JsObject::from_proto_and_data_with_shared_shape(context.root_shape(), prototype, tag);
+        let locale = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
+            context.root_shape(),
+            prototype,
+            tag,
+        );
 
         // 39. Return locale.
         Ok(locale.into())
@@ -369,10 +373,13 @@ impl Locale {
 
         // 4. Return ! Construct(%Locale%, maximal).
         let prototype = context.intrinsics().constructors().locale().prototype();
-        Ok(
-            JsObject::from_proto_and_data_with_shared_shape(context.root_shape(), prototype, loc)
-                .into(),
+        Ok(JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
+            context.root_shape(),
+            prototype,
+            loc,
         )
+        .into())
     }
 
     /// [`Intl.Locale.prototype.minimize ( )`][spec]
@@ -410,10 +417,13 @@ impl Locale {
 
         // 4. Return ! Construct(%Locale%, minimal).
         let prototype = context.intrinsics().constructors().locale().prototype();
-        Ok(
-            JsObject::from_proto_and_data_with_shared_shape(context.root_shape(), prototype, loc)
-                .into(),
+        Ok(JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
+            context.root_shape(),
+            prototype,
+            loc,
         )
+        .into())
     }
 
     /// [`Intl.Locale.prototype.toString ( )`][spec].
diff --git a/core/engine/src/builtins/intl/mod.rs b/core/engine/src/builtins/intl/mod.rs
index 401e5524e9f..afd24d3c4b2 100644
--- a/core/engine/src/builtins/intl/mod.rs
+++ b/core/engine/src/builtins/intl/mod.rs
@@ -119,8 +119,8 @@ impl Intl {
 }
 
 impl IntrinsicObject for Intl {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::with_intrinsic::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::with_intrinsic::<Self>(realm, mc)
             .static_property(
                 JsSymbol::to_string_tag(),
                 Self::NAME,
diff --git a/core/engine/src/builtins/intl/number_format/mod.rs b/core/engine/src/builtins/intl/number_format/mod.rs
index 5cbb36e60c2..d8253b0b581 100644
--- a/core/engine/src/builtins/intl/number_format/mod.rs
+++ b/core/engine/src/builtins/intl/number_format/mod.rs
@@ -162,12 +162,12 @@ impl Service for NumberFormat {
 }
 
 impl IntrinsicObject for NumberFormat {
-    fn init(realm: &Realm) {
-        let get_format = BuiltInBuilder::callable(realm, Self::get_format)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        let get_format = BuiltInBuilder::callable(realm, Self::get_format, mc)
             .name(js_string!("get format"))
             .build();
 
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .static_method(
                 Self::supported_locales_of,
                 js_string!("supportedLocalesOf"),
@@ -242,6 +242,7 @@ impl BuiltInConstructor for NumberFormat {
         let number_format = Self::new(locales, options, context)?;
 
         let number_format = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             prototype,
             number_format,
@@ -605,6 +606,7 @@ impl NumberFormat {
             //     c. Set nf.[[BoundFormat]] to F.
             let bound_format = FunctionObjectBuilder::new(
                 context.realm(),
+                context.gc_collector(),
                 // Number Format Functions
                 // <https://tc39.es/ecma402/#sec-number-format-functions>
                 NativeFunction::from_copy_closure_with_captures(
diff --git a/core/engine/src/builtins/intl/options.rs b/core/engine/src/builtins/intl/options.rs
index 52543429017..93d08e24ff7 100644
--- a/core/engine/src/builtins/intl/options.rs
+++ b/core/engine/src/builtins/intl/options.rs
@@ -153,6 +153,7 @@ pub(super) fn coerce_options_to_object(
     if options.is_undefined() {
         // a. Return OrdinaryObjectCreate(null).
         return Ok(JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             None,
             OrdinaryObject,
diff --git a/core/engine/src/builtins/intl/plural_rules/mod.rs b/core/engine/src/builtins/intl/plural_rules/mod.rs
index 36787b4edda..d1a7bde8b1a 100644
--- a/core/engine/src/builtins/intl/plural_rules/mod.rs
+++ b/core/engine/src/builtins/intl/plural_rules/mod.rs
@@ -47,8 +47,8 @@ impl Service for PluralRules {
 }
 
 impl IntrinsicObject for PluralRules {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .static_method(
                 Self::supported_locales_of,
                 js_string!("supportedLocalesOf"),
@@ -151,6 +151,7 @@ impl BuiltInConstructor for PluralRules {
 
         // 12. Return pluralRules.
         Ok(JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             proto,
             Self {
diff --git a/core/engine/src/builtins/intl/segmenter/iterator.rs b/core/engine/src/builtins/intl/segmenter/iterator.rs
index ceb7c1222f2..fb361570826 100644
--- a/core/engine/src/builtins/intl/segmenter/iterator.rs
+++ b/core/engine/src/builtins/intl/segmenter/iterator.rs
@@ -59,8 +59,8 @@ pub(crate) struct SegmentIterator {
 }
 
 impl IntrinsicObject for SegmentIterator {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::with_intrinsic::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::with_intrinsic::<Self>(realm, mc)
             .static_property(
                 JsSymbol::to_string_tag(),
                 js_string!("Segmenter String Iterator"),
@@ -87,6 +87,7 @@ impl SegmentIterator {
         // 5. Set iterator.[[IteratedStringNextSegmentCodeUnitIndex]] to 0.
         // 6. Return iterator.
         JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             context
                 .intrinsics()
diff --git a/core/engine/src/builtins/intl/segmenter/mod.rs b/core/engine/src/builtins/intl/segmenter/mod.rs
index 459a385f6ed..120f17d0d26 100644
--- a/core/engine/src/builtins/intl/segmenter/mod.rs
+++ b/core/engine/src/builtins/intl/segmenter/mod.rs
@@ -103,8 +103,8 @@ impl Service for Segmenter {
 }
 
 impl IntrinsicObject for Segmenter {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .static_method(
                 Self::supported_locales_of,
                 js_string!("supportedLocalesOf"),
@@ -155,7 +155,7 @@ impl BuiltInConstructor for Segmenter {
         let requested_locales = canonicalize_locale_list(locales, context)?;
 
         // 5. Set options to ? GetOptionsObject(options).
-        let options = get_options_object(options)?;
+        let options = get_options_object(options, context.gc_collector())?;
 
         // 6. Let opt be a new Record.
         // 7. Let matcher be ? GetOption(options, "localeMatcher", string, « "lookup", "best fit" », "best fit").
@@ -214,8 +214,12 @@ impl BuiltInConstructor for Segmenter {
         let proto =
             get_prototype_from_constructor(new_target, StandardConstructors::segmenter, context)?;
 
-        let segmenter =
-            JsObject::from_proto_and_data_with_shared_shape(context.root_shape(), proto, segmenter);
+        let segmenter = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
+            context.root_shape(),
+            proto,
+            segmenter,
+        );
 
         // 14. Return segmenter.
         Ok(segmenter.into())
diff --git a/core/engine/src/builtins/intl/segmenter/segments.rs b/core/engine/src/builtins/intl/segmenter/segments.rs
index f489dce1247..248acc71318 100644
--- a/core/engine/src/builtins/intl/segmenter/segments.rs
+++ b/core/engine/src/builtins/intl/segmenter/segments.rs
@@ -19,8 +19,8 @@ pub(crate) struct Segments {
 }
 
 impl IntrinsicObject for Segments {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::with_intrinsic::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::with_intrinsic::<Self>(realm, mc)
             .static_method(Self::containing, js_string!("containing"), 1)
             .static_method(Self::iterator, JsSymbol::iterator(), 0)
             .build();
@@ -42,6 +42,7 @@ impl Segments {
         // 4. Set segments.[[SegmentsString]] to string.
         // 5. Return segments.
         JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             context.intrinsics().objects().segments_prototype(),
             Self { segmenter, string },
diff --git a/core/engine/src/builtins/iterable/async_from_sync_iterator.rs b/core/engine/src/builtins/iterable/async_from_sync_iterator.rs
index 56b198e80e3..d1c2bbd4e6d 100644
--- a/core/engine/src/builtins/iterable/async_from_sync_iterator.rs
+++ b/core/engine/src/builtins/iterable/async_from_sync_iterator.rs
@@ -26,8 +26,8 @@ pub(crate) struct AsyncFromSyncIterator {
 }
 
 impl IntrinsicObject for AsyncFromSyncIterator {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::with_intrinsic::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::with_intrinsic::<Self>(realm, mc)
             .prototype(
                 realm
                     .intrinsics()
@@ -63,6 +63,7 @@ impl AsyncFromSyncIterator {
         // 1. Let asyncIterator be OrdinaryObjectCreate(%AsyncFromSyncIteratorPrototype%, « [[SyncIteratorRecord]] »).
         // 2. Set asyncIterator.[[SyncIteratorRecord]] to syncIteratorRecord.
         let async_iterator = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             context
                 .intrinsics()
@@ -82,7 +83,7 @@ impl AsyncFromSyncIterator {
 
         // 4. Let iteratorRecord be the Iterator Record { [[Iterator]]: asyncIterator, [[NextMethod]]: nextMethod, [[Done]]: false }.
         // 5. Return iteratorRecord.
-        IteratorRecord::new(async_iterator, next_method)
+        IteratorRecord::new(async_iterator, next_method, context.gc_collector())
     }
 
     /// `%AsyncFromSyncIteratorPrototype%.next ( [ value ] )`
@@ -362,6 +363,7 @@ impl AsyncFromSyncIterator {
         // 10. Let onFulfilled be CreateBuiltinFunction(unwrap, 1, "", « »).
         let on_fulfilled = FunctionObjectBuilder::new(
             context.realm(),
+            context.gc_collector(),
             NativeFunction::from_copy_closure(move |_this, args, context| {
                 // a. Return CreateIterResultObject(value, done).
                 Ok(create_iter_result_object(
@@ -393,6 +395,7 @@ impl AsyncFromSyncIterator {
             Some(
                 FunctionObjectBuilder::new(
                     context.realm(),
+                    context.gc_collector(),
                     NativeFunction::from_copy_closure_with_captures(
                         |_this, args, iter, context| {
                             // i. Return ? IteratorClose(syncIteratorRecord, ThrowCompletion(error)).
diff --git a/core/engine/src/builtins/iterable/iterator_constructor.rs b/core/engine/src/builtins/iterable/iterator_constructor.rs
index 3f9b2c26f5a..0d29a8e20f7 100644
--- a/core/engine/src/builtins/iterable/iterator_constructor.rs
+++ b/core/engine/src/builtins/iterable/iterator_constructor.rs
@@ -40,9 +40,9 @@ use super::{iterator_helper::IteratorHelper, wrap_for_valid_iterator::WrapForVal
 pub(crate) struct IteratorConstructor;
 
 impl IntrinsicObject for IteratorConstructor {
-    fn init(realm: &Realm) {
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
         let iterator_prototype = realm.intrinsics().constructors().iterator().prototype();
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .inherits(Some(iterator_prototype.clone()))
             // Static methods
             .static_method(Self::from, js_string!("from"), 1)
@@ -101,6 +101,7 @@ impl BuiltInConstructor for IteratorConstructor {
 
         // Create an ordinary object (Iterator instances have no internal data slots).
         Ok(JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             prototype,
             OrdinaryObject,
@@ -141,6 +142,7 @@ impl IteratorConstructor {
         // 5. Set wrapper.[[Iterated]] to iteratorRecord.
         // 6. Return wrapper.
         let wrapper = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             context
                 .intrinsics()
diff --git a/core/engine/src/builtins/iterable/iterator_helper/mod.rs b/core/engine/src/builtins/iterable/iterator_helper/mod.rs
index 862046a2a58..89c3df3f7ee 100644
--- a/core/engine/src/builtins/iterable/iterator_helper/mod.rs
+++ b/core/engine/src/builtins/iterable/iterator_helper/mod.rs
@@ -75,8 +75,8 @@ pub(crate) struct IteratorHelper {
 }
 
 impl IntrinsicObject for IteratorHelper {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::with_intrinsic::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::with_intrinsic::<Self>(realm, mc)
             .prototype(realm.intrinsics().constructors().iterator().prototype())
             .static_method(Self::next, js_string!("next"), 0)
             .static_method(Self::r#return, js_string!("return"), 0)
@@ -296,6 +296,7 @@ impl IteratorHelper {
         //     ).
         // ii. Set result.[[UnderlyingIterators]] to « iterated ».
         JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             context
                 .intrinsics()
diff --git a/core/engine/src/builtins/iterable/iterator_prototype.rs b/core/engine/src/builtins/iterable/iterator_prototype.rs
index 189f7369804..f244ae1c6f3 100644
--- a/core/engine/src/builtins/iterable/iterator_prototype.rs
+++ b/core/engine/src/builtins/iterable/iterator_prototype.rs
@@ -26,20 +26,20 @@ use crate::{
 pub(crate) struct Iterator;
 
 impl IntrinsicObject for Iterator {
-    fn init(realm: &Realm) {
-        let get_constructor = BuiltInBuilder::callable(realm, Self::get_constructor)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        let get_constructor = BuiltInBuilder::callable(realm, Self::get_constructor, mc)
             .name(js_string!("get constructor"))
             .build();
-        let set_constructor = BuiltInBuilder::callable(realm, Self::set_constructor)
+        let set_constructor = BuiltInBuilder::callable(realm, Self::set_constructor, mc)
             .name(js_string!("set constructor"))
             .build();
-        let get_to_string_tag = BuiltInBuilder::callable(realm, Self::get_to_string_tag)
+        let get_to_string_tag = BuiltInBuilder::callable(realm, Self::get_to_string_tag, mc)
             .name(js_string!("get [Symbol.toStringTag]"))
             .build();
-        let set_to_string_tag = BuiltInBuilder::callable(realm, Self::set_to_string_tag)
+        let set_to_string_tag = BuiltInBuilder::callable(realm, Self::set_to_string_tag, mc)
             .name(js_string!("set [Symbol.toStringTag]"))
             .build();
-        let builder = BuiltInBuilder::with_intrinsic::<Self>(realm)
+        let builder = BuiltInBuilder::with_intrinsic::<Self>(realm, mc)
             .static_method(|v, _, _| Ok(v.clone()), JsSymbol::iterator(), 0)
             .static_method(Self::map, js_string!("map"), 1)
             .static_method(Self::filter, js_string!("filter"), 1)
@@ -217,7 +217,7 @@ impl Iterator {
             .ok_or_else(|| js_error!(TypeError: "Iterator.prototype.map called on non-object"))?;
 
         // 3. Let iterated be the Iterator Record { [[Iterator]]: O, [[NextMethod]]: undefined, [[Done]]: false }.
-        let iterated = IteratorRecord::new(o, JsValue::undefined());
+        let iterated = IteratorRecord::new(o, JsValue::undefined(), context.gc_collector());
 
         // 4. If IsCallable(mapper) is false, then
         //    a. Let error be ThrowCompletion(a newly created TypeError object).
@@ -255,7 +255,7 @@ impl Iterator {
         )?;
 
         // 3. Let iterated be the Iterator Record { [[Iterator]]: O, [[NextMethod]]: undefined, [[Done]]: false }.
-        let iterated = IteratorRecord::new(o, JsValue::undefined());
+        let iterated = IteratorRecord::new(o, JsValue::undefined(), context.gc_collector());
 
         // 4. If IsCallable(predicate) is false, then
         //    a. Let error be ThrowCompletion(a newly created TypeError object).
@@ -295,7 +295,7 @@ impl Iterator {
             .ok_or_else(|| js_error!(TypeError: "Iterator.prototype.take called on non-object"))?;
 
         // 3. Let iterated be the Iterator Record { [[Iterator]]: O, [[NextMethod]]: undefined, [[Done]]: false }.
-        let iterated = IteratorRecord::new(o, JsValue::undefined());
+        let iterated = IteratorRecord::new(o, JsValue::undefined(), context.gc_collector());
 
         // 4. Let numLimit be Completion(ToNumber(limit)).
         // 5. IfAbruptCloseIterator(numLimit, iterated).
@@ -356,7 +356,7 @@ impl Iterator {
             .ok_or_else(|| js_error!(TypeError: "Iterator.prototype.drop called on non-object"))?;
 
         // 3. Let iterated be the Iterator Record { [[Iterator]]: O, [[NextMethod]]: undefined, [[Done]]: false }.
-        let iterated = IteratorRecord::new(o.clone(), JsValue::undefined());
+        let iterated = IteratorRecord::new(o.clone(), JsValue::undefined(), context.gc_collector());
 
         // 4. Let numLimit be Completion(ToNumber(limit)).
         // 5. IfAbruptCloseIterator(numLimit, iterated).
@@ -416,7 +416,7 @@ impl Iterator {
         )?;
 
         // 3. Let iterated be the Iterator Record { [[Iterator]]: O, [[NextMethod]]: undefined, [[Done]]: false }.
-        let iterated = IteratorRecord::new(o, JsValue::undefined());
+        let iterated = IteratorRecord::new(o, JsValue::undefined(), context.gc_collector());
 
         // 4. If IsCallable(mapper) is false, then
         //    a. Let error be ThrowCompletion(a newly created TypeError object).
@@ -454,7 +454,8 @@ impl Iterator {
         )?;
 
         // 3. Let iterated be the Iterator Record { [[Iterator]]: O, [[NextMethod]]: undefined, [[Done]]: false }.
-        let iterated = IteratorRecord::new(obj.clone(), JsValue::undefined());
+        let iterated =
+            IteratorRecord::new(obj.clone(), JsValue::undefined(), context.gc_collector());
 
         let search_element = args.get_or_undefined(0);
 
@@ -525,7 +526,7 @@ impl Iterator {
         )?;
 
         // 3. Let iterated be the Iterator Record { [[Iterator]]: O, [[NextMethod]]: undefined, [[Done]]: false }.
-        let iterated = IteratorRecord::new(o, JsValue::undefined());
+        let iterated = IteratorRecord::new(o, JsValue::undefined(), context.gc_collector());
 
         // 4. If IsCallable(reducer) is false, then
         let Some(reducer) = args.get_or_undefined(0).as_callable() else {
@@ -620,7 +621,7 @@ impl Iterator {
         )?;
 
         // 3. Let iterated be the Iterator Record { [[Iterator]]: O, [[NextMethod]]: undefined, [[Done]]: false }.
-        let iterated = IteratorRecord::new(o, JsValue::undefined());
+        let iterated = IteratorRecord::new(o, JsValue::undefined(), context.gc_collector());
 
         // 4. If IsCallable(fn) is false, then
         let Some(func) = args.get_or_undefined(0).as_callable() else {
@@ -676,7 +677,7 @@ impl Iterator {
             .ok_or_else(|| js_error!(TypeError: "Iterator.prototype.some called on non-object"))?;
 
         // 3. Let iterated be the Iterator Record { [[Iterator]]: O, [[NextMethod]]: undefined, [[Done]]: false }.
-        let iterated = IteratorRecord::new(o, JsValue::undefined());
+        let iterated = IteratorRecord::new(o, JsValue::undefined(), context.gc_collector());
 
         // 4. If IsCallable(predicate) is false, then
         let Some(predicate) = args.get_or_undefined(0).as_callable() else {
@@ -735,7 +736,7 @@ impl Iterator {
             .ok_or_else(|| js_error!(TypeError: "Iterator.prototype.every called on non-object"))?;
 
         // 3. Let iterated be the Iterator Record { [[Iterator]]: O, [[NextMethod]]: undefined, [[Done]]: false }.
-        let iterated = IteratorRecord::new(o, JsValue::undefined());
+        let iterated = IteratorRecord::new(o, JsValue::undefined(), context.gc_collector());
 
         // 4. If IsCallable(predicate) is false, then
         let Some(predicate) = args.get_or_undefined(0).as_callable() else {
@@ -795,7 +796,7 @@ impl Iterator {
             .ok_or_else(|| js_error!(TypeError: "Iterator.prototype.find called on non-object"))?;
 
         // 3. Let iterated be the Iterator Record { [[Iterator]]: O, [[NextMethod]]: undefined, [[Done]]: false }.
-        let iterated = IteratorRecord::new(o, JsValue::undefined());
+        let iterated = IteratorRecord::new(o, JsValue::undefined(), context.gc_collector());
 
         // 4. If IsCallable(predicate) is false, then
         let Some(predicate) = args.get_or_undefined(0).as_callable() else {
diff --git a/core/engine/src/builtins/iterable/mod.rs b/core/engine/src/builtins/iterable/mod.rs
index 835a71ebacf..032bae56384 100644
--- a/core/engine/src/builtins/iterable/mod.rs
+++ b/core/engine/src/builtins/iterable/mod.rs
@@ -98,18 +98,18 @@ impl Default for IteratorPrototypes {
 impl IteratorPrototypes {
     pub(crate) fn uninit_in(mc: &boa_gc::MutationContext<'static, '_>) -> Self {
         Self {
-            iterator: JsObject::with_null_proto_in(mc),
-            async_iterator: JsObject::with_null_proto_in(mc),
-            async_from_sync_iterator: JsObject::with_null_proto_in(mc),
-            array: JsObject::with_null_proto_in(mc),
-            set: JsObject::with_null_proto_in(mc),
-            string: JsObject::with_null_proto_in(mc),
-            regexp_string: JsObject::with_null_proto_in(mc),
-            map: JsObject::with_null_proto_in(mc),
+            iterator: JsObject::with_null_proto(mc),
+            async_iterator: JsObject::with_null_proto(mc),
+            async_from_sync_iterator: JsObject::with_null_proto(mc),
+            array: JsObject::with_null_proto(mc),
+            set: JsObject::with_null_proto(mc),
+            string: JsObject::with_null_proto(mc),
+            regexp_string: JsObject::with_null_proto(mc),
+            map: JsObject::with_null_proto(mc),
             #[cfg(feature = "intl")]
-            segment: JsObject::with_null_proto_in(mc),
-            iterator_helper: JsObject::with_null_proto_in(mc),
-            wrap_for_valid_iterator: JsObject::with_null_proto_in(mc),
+            segment: JsObject::with_null_proto(mc),
+            iterator_helper: JsObject::with_null_proto(mc),
+            wrap_for_valid_iterator: JsObject::with_null_proto(mc),
         }
     }
     /// Returns the `ArrayIteratorPrototype` object.
@@ -193,8 +193,8 @@ impl IteratorPrototypes {
 pub(crate) struct AsyncIterator;
 
 impl IntrinsicObject for AsyncIterator {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::with_intrinsic::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::with_intrinsic::<Self>(realm, mc)
             .static_method(|v, _, _| Ok(v.clone()), JsSymbol::async_iterator(), 0)
             .build();
     }
@@ -212,11 +212,11 @@ pub fn create_iter_result_object(value: JsValue, done: bool, context: &mut Conte
     // 2. Let obj be ! OrdinaryObjectCreate(%Object.prototype%).
     // 3. Perform ! CreateDataPropertyOrThrow(obj, "value", value).
     // 4. Perform ! CreateDataPropertyOrThrow(obj, "done", done).
-    let obj = context
-        .intrinsics()
-        .templates()
-        .iterator_result()
-        .create(OrdinaryObject, vec![value, done.into()]);
+    let obj = context.intrinsics().templates().iterator_result().create(
+        context.gc_collector(),
+        OrdinaryObject,
+        vec![value, done.into()],
+    );
 
     // 5. Return obj.
     obj.into()
@@ -254,7 +254,11 @@ impl JsValue {
         let next_method = iterator_obj.get(js_string!("next"), context)?;
         // 4. Let iteratorRecord be the Iterator Record { [[Iterator]]: iterator, [[NextMethod]]: nextMethod, [[Done]]: false }.
         // 5. Return iteratorRecord.
-        Ok(IteratorRecord::new(iterator_obj.clone(), next_method))
+        Ok(IteratorRecord::new(
+            iterator_obj.clone(),
+            next_method,
+            context.gc_collector(),
+        ))
     }
 
     /// `GetIterator ( obj, kind )`
@@ -403,13 +407,17 @@ impl IteratorRecord {
     /// Creates a new `IteratorRecord` with the given iterator object, next method and `done` flag.
     #[inline]
     #[must_use]
-    pub fn new(iterator: JsObject, next_method: JsValue) -> Self {
+    pub fn new(
+        iterator: JsObject,
+        next_method: JsValue,
+        mc: &boa_gc::MutationContext<'static, '_>,
+    ) -> Self {
         Self {
             iterator,
             next_method,
             done: false,
             last_result: IteratorResult {
-                object: JsObject::with_null_proto(),
+                object: JsObject::with_null_proto(mc),
             },
         }
     }
@@ -697,7 +705,11 @@ pub(crate) fn get_iterator_direct(
     let next_method = obj.get(js_string!("next"), context)?;
     // 2. Let iteratorRecord be the Iterator Record { [[Iterator]]: obj, [[NextMethod]]: nextMethod, [[Done]]: false }.
     // 3. Return iteratorRecord.
-    Ok(IteratorRecord::new(obj.clone(), next_method))
+    Ok(IteratorRecord::new(
+        obj.clone(),
+        next_method,
+        context.gc_collector(),
+    ))
 }
 
 /// `GetIteratorFlattenable ( obj, stringHandling )`
diff --git a/core/engine/src/builtins/iterable/wrap_for_valid_iterator.rs b/core/engine/src/builtins/iterable/wrap_for_valid_iterator.rs
index a15270e66d6..8500e690921 100644
--- a/core/engine/src/builtins/iterable/wrap_for_valid_iterator.rs
+++ b/core/engine/src/builtins/iterable/wrap_for_valid_iterator.rs
@@ -34,8 +34,8 @@ pub(crate) struct WrapForValidIterator {
 }
 
 impl IntrinsicObject for WrapForValidIterator {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::with_intrinsic::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::with_intrinsic::<Self>(realm, mc)
             .prototype(realm.intrinsics().constructors().iterator().prototype())
             .static_method(Self::next, js_string!("next"), 0)
             .static_method(Self::r#return, js_string!("return"), 0)
diff --git a/core/engine/src/builtins/json/mod.rs b/core/engine/src/builtins/json/mod.rs
index 9d82c87eac9..52553eb6a83 100644
--- a/core/engine/src/builtins/json/mod.rs
+++ b/core/engine/src/builtins/json/mod.rs
@@ -200,11 +200,11 @@ impl<'ast> boa_ast::visitor::Visitor<'ast> for JsonSourceVisitor<'_> {
 pub(crate) struct Json;
 
 impl IntrinsicObject for Json {
-    fn init(realm: &Realm) {
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
         let to_string_tag = JsSymbol::to_string_tag();
         let attribute = Attribute::READONLY | Attribute::NON_ENUMERABLE | Attribute::CONFIGURABLE;
 
-        BuiltInBuilder::with_intrinsic::<Self>(realm)
+        BuiltInBuilder::with_intrinsic::<Self>(realm, mc)
             .static_method(Self::parse, js_string!("parse"), 2)
             .static_method(Self::stringify, js_string!("stringify"), 3)
             .static_method(Self::raw_json, js_string!("rawJSON"), 1)
@@ -338,7 +338,7 @@ impl Json {
         // 11. If IsCallable(reviver) is true, then
         if let Some(obj) = args.get_or_undefined(1).as_callable() {
             // a. Let root be ! OrdinaryObjectCreate(%Object.prototype%).
-            let root = JsObject::with_object_proto(context.intrinsics());
+            let root = JsObject::with_object_proto(context.gc_collector(), context.intrinsics());
 
             // b. Let rootName be the empty String.
             // c. Perform ! CreateDataPropertyOrThrow(root, rootName, unfiltered).
@@ -467,7 +467,7 @@ impl Json {
         // For objects/arrays or modified values: context = {} (no source property)
         // Per spec, source is only provided when the value is still the same
         // primitive that was produced by parsing the original JSON text.
-        let ctx_obj = JsObject::with_object_proto(context.intrinsics());
+        let ctx_obj = JsObject::with_object_proto(context.gc_collector(), context.intrinsics());
         if let Some(JsonNode::Primitive(source_text)) = source_node {
             // Check if the current value matches what the source text produces.
             // If the reviver modified the value, it won't match and we skip source.
@@ -571,7 +571,7 @@ impl Json {
 
         // 3. Let internalSlotsList be « [[IsRawJSON]] ».
         // 4. Let obj be OrdinaryObjectCreate(null, internalSlotsList).
-        let obj = JsObject::from_proto_and_data(None::<JsObject>, RawJson);
+        let obj = JsObject::from_proto_and_data(context.gc_collector(), None::<JsObject>, RawJson);
 
         // 5. Perform ! CreateDataPropertyOrThrow(obj, "rawJSON", jsonString).
         obj.create_data_property_or_throw(js_string!("rawJSON"), json_string, context)
@@ -738,7 +738,7 @@ impl Json {
         };
 
         // 9. Let wrapper be ! OrdinaryObjectCreate(%Object.prototype%).
-        let wrapper = JsObject::with_object_proto(context.intrinsics());
+        let wrapper = JsObject::with_object_proto(context.gc_collector(), context.intrinsics());
 
         // 10. Perform ! CreateDataPropertyOrThrow(wrapper, the empty String, value).
         wrapper
diff --git a/core/engine/src/builtins/map/map_iterator.rs b/core/engine/src/builtins/map/map_iterator.rs
index 67233688762..326f28a8567 100644
--- a/core/engine/src/builtins/map/map_iterator.rs
+++ b/core/engine/src/builtins/map/map_iterator.rs
@@ -52,8 +52,8 @@ pub(crate) struct MapIterator {
 }
 
 impl IntrinsicObject for MapIterator {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::with_intrinsic::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::with_intrinsic::<Self>(realm, mc)
             .prototype(realm.intrinsics().constructors().iterator().prototype())
             .static_method(Self::next, js_string!("next"), 0)
             .static_property(
@@ -89,6 +89,7 @@ impl MapIterator {
             iteration_kind: kind,
         };
         let map_iterator = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             context.intrinsics().objects().iterator_prototypes().map(),
             iter,
diff --git a/core/engine/src/builtins/map/mod.rs b/core/engine/src/builtins/map/mod.rs
index 9d5900961b0..81fa5862f4c 100644
--- a/core/engine/src/builtins/map/mod.rs
+++ b/core/engine/src/builtins/map/mod.rs
@@ -41,20 +41,20 @@ mod tests;
 pub(crate) struct Map;
 
 impl IntrinsicObject for Map {
-    fn init(realm: &Realm) {
-        let get_species = BuiltInBuilder::callable(realm, Self::get_species)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        let get_species = BuiltInBuilder::callable(realm, Self::get_species, mc)
             .name(js_string!("get [Symbol.species]"))
             .build();
 
-        let get_size = BuiltInBuilder::callable(realm, Self::get_size)
+        let get_size = BuiltInBuilder::callable(realm, Self::get_size, mc)
             .name(js_string!("get size"))
             .build();
 
-        let entries_function = BuiltInBuilder::callable(realm, Self::entries)
+        let entries_function = BuiltInBuilder::callable(realm, Self::entries, mc)
             .name(js_string!("entries"))
             .build();
 
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .static_method(Self::group_by, js_string!("groupBy"), 2)
             .static_accessor(
                 JsSymbol::species(),
@@ -144,6 +144,7 @@ impl BuiltInConstructor for Map {
         let prototype =
             get_prototype_from_constructor(new_target, StandardConstructors::map, context)?;
         let map = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             prototype,
             <OrderedMap<JsValue>>::new(),
@@ -797,10 +798,13 @@ impl Map {
         let proto = context.intrinsics().constructors().map().prototype();
 
         // 4. Return map.
-        Ok(
-            JsObject::from_proto_and_data_with_shared_shape(context.root_shape(), proto, map)
-                .into(),
+        Ok(JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
+            context.root_shape(),
+            proto,
+            map,
         )
+        .into())
     }
 }
 
diff --git a/core/engine/src/builtins/math/mod.rs b/core/engine/src/builtins/math/mod.rs
index 9d842188c1d..f0abaf7d019 100644
--- a/core/engine/src/builtins/math/mod.rs
+++ b/core/engine/src/builtins/math/mod.rs
@@ -27,9 +27,9 @@ mod tests;
 pub(crate) struct Math;
 
 impl IntrinsicObject for Math {
-    fn init(realm: &Realm) {
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
         let attribute = Attribute::READONLY | Attribute::NON_ENUMERABLE | Attribute::PERMANENT;
-        let builder = BuiltInBuilder::with_intrinsic::<Self>(realm)
+        let builder = BuiltInBuilder::with_intrinsic::<Self>(realm, mc)
             .static_property(js_string!("E"), std::f64::consts::E, attribute)
             .static_property(js_string!("LN10"), std::f64::consts::LN_10, attribute)
             .static_property(js_string!("LN2"), std::f64::consts::LN_2, attribute)
diff --git a/core/engine/src/builtins/mod.rs b/core/engine/src/builtins/mod.rs
index 6b6e8470ec3..4857922eed0 100644
--- a/core/engine/src/builtins/mod.rs
+++ b/core/engine/src/builtins/mod.rs
@@ -130,7 +130,7 @@ pub(crate) trait IntrinsicObject {
     ///
     /// This is where the methods, properties, static methods and the constructor of a built-in must
     /// be initialized to be accessible from ECMAScript.
-    fn init(realm: &Realm);
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>);
 
     /// Gets the intrinsic object.
     fn get(intrinsics: &Intrinsics) -> JsObject;
@@ -242,113 +242,113 @@ impl Realm {
     /// Abstract operation [`CreateIntrinsics ( realmRec )`][spec]
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-createintrinsics
-    pub(crate) fn initialize(&self) {
-        BuiltInFunctionObject::init(self);
-        OrdinaryObject::init(self);
-        Iterator::init(self);
-        AsyncIterator::init(self);
-        AsyncFromSyncIterator::init(self);
-        IteratorConstructor::init(self);
-        WrapForValidIterator::init(self);
-        IteratorHelper::init(self);
-        Math::init(self);
-        Json::init(self);
-        Array::init(self);
-        ArrayIterator::init(self);
-        Proxy::init(self);
-        ArrayBuffer::init(self);
-        SharedArrayBuffer::init(self);
-        BigInt::init(self);
-        Boolean::init(self);
-        Date::init(self);
-        DataView::init(self);
-        Map::init(self);
-        MapIterator::init(self);
-        IsFinite::init(self);
-        IsNaN::init(self);
-        ParseInt::init(self);
-        ParseFloat::init(self);
-        Number::init(self);
-        Eval::init(self);
-        Set::init(self);
-        SetIterator::init(self);
-        String::init(self);
-        StringIterator::init(self);
-        RegExp::init(self);
-        RegExpStringIterator::init(self);
-        BuiltinTypedArray::init(self);
-        Int8Array::init(self);
-        Uint8Array::init(self);
-        Uint8ClampedArray::init(self);
-        Int16Array::init(self);
-        Uint16Array::init(self);
-        Int32Array::init(self);
-        Uint32Array::init(self);
-        BigInt64Array::init(self);
-        BigUint64Array::init(self);
+    pub(crate) fn initialize(&self, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInFunctionObject::init(self, mc);
+        OrdinaryObject::init(self, mc);
+        Iterator::init(self, mc);
+        AsyncIterator::init(self, mc);
+        AsyncFromSyncIterator::init(self, mc);
+        IteratorConstructor::init(self, mc);
+        WrapForValidIterator::init(self, mc);
+        IteratorHelper::init(self, mc);
+        Math::init(self, mc);
+        Json::init(self, mc);
+        Array::init(self, mc);
+        ArrayIterator::init(self, mc);
+        Proxy::init(self, mc);
+        ArrayBuffer::init(self, mc);
+        SharedArrayBuffer::init(self, mc);
+        BigInt::init(self, mc);
+        Boolean::init(self, mc);
+        Date::init(self, mc);
+        DataView::init(self, mc);
+        Map::init(self, mc);
+        MapIterator::init(self, mc);
+        IsFinite::init(self, mc);
+        IsNaN::init(self, mc);
+        ParseInt::init(self, mc);
+        ParseFloat::init(self, mc);
+        Number::init(self, mc);
+        Eval::init(self, mc);
+        Set::init(self, mc);
+        SetIterator::init(self, mc);
+        String::init(self, mc);
+        StringIterator::init(self, mc);
+        RegExp::init(self, mc);
+        RegExpStringIterator::init(self, mc);
+        BuiltinTypedArray::init(self, mc);
+        Int8Array::init(self, mc);
+        Uint8Array::init(self, mc);
+        Uint8ClampedArray::init(self, mc);
+        Int16Array::init(self, mc);
+        Uint16Array::init(self, mc);
+        Int32Array::init(self, mc);
+        Uint32Array::init(self, mc);
+        BigInt64Array::init(self, mc);
+        BigUint64Array::init(self, mc);
         #[cfg(feature = "float16")]
-        typed_array::Float16Array::init(self);
-        Float32Array::init(self);
-        Float64Array::init(self);
-        Symbol::init(self);
-        Error::init(self);
-        RangeError::init(self);
-        ReferenceError::init(self);
-        TypeError::init(self);
-        ThrowTypeError::init(self);
-        SyntaxError::init(self);
-        EvalError::init(self);
-        UriError::init(self);
-        AggregateError::init(self);
-        Reflect::init(self);
-        Generator::init(self);
-        GeneratorFunction::init(self);
-        Promise::init(self);
-        AsyncFunction::init(self);
-        AsyncGenerator::init(self);
-        AsyncGeneratorFunction::init(self);
-        EncodeUri::init(self);
-        EncodeUriComponent::init(self);
-        DecodeUri::init(self);
-        DecodeUriComponent::init(self);
-        WeakRef::init(self);
-        WeakMap::init(self);
-        WeakSet::init(self);
-        Atomics::init(self);
-        FinalizationRegistry::init(self);
+        typed_array::Float16Array::init(self, mc);
+        Float32Array::init(self, mc);
+        Float64Array::init(self, mc);
+        Symbol::init(self, mc);
+        Error::init(self, mc);
+        RangeError::init(self, mc);
+        ReferenceError::init(self, mc);
+        TypeError::init(self, mc);
+        ThrowTypeError::init(self, mc);
+        SyntaxError::init(self, mc);
+        EvalError::init(self, mc);
+        UriError::init(self, mc);
+        AggregateError::init(self, mc);
+        Reflect::init(self, mc);
+        Generator::init(self, mc);
+        GeneratorFunction::init(self, mc);
+        Promise::init(self, mc);
+        AsyncFunction::init(self, mc);
+        AsyncGenerator::init(self, mc);
+        AsyncGeneratorFunction::init(self, mc);
+        EncodeUri::init(self, mc);
+        EncodeUriComponent::init(self, mc);
+        DecodeUri::init(self, mc);
+        DecodeUriComponent::init(self, mc);
+        WeakRef::init(self, mc);
+        WeakMap::init(self, mc);
+        WeakSet::init(self, mc);
+        Atomics::init(self, mc);
+        FinalizationRegistry::init(self, mc);
 
         #[cfg(feature = "annex-b")]
         {
-            escape::Escape::init(self);
-            escape::Unescape::init(self);
+            escape::Escape::init(self, mc);
+            escape::Unescape::init(self, mc);
         }
 
         #[cfg(feature = "intl")]
         {
-            intl::Intl::init(self);
-            intl::Collator::init(self);
-            intl::ListFormat::init(self);
-            intl::Locale::init(self);
-            intl::DateTimeFormat::init(self);
-            intl::Segmenter::init(self);
-            intl::segmenter::Segments::init(self);
-            intl::segmenter::SegmentIterator::init(self);
-            intl::PluralRules::init(self);
-            intl::NumberFormat::init(self);
+            intl::Intl::init(self, mc);
+            intl::Collator::init(self, mc);
+            intl::ListFormat::init(self, mc);
+            intl::Locale::init(self, mc);
+            intl::DateTimeFormat::init(self, mc);
+            intl::Segmenter::init(self, mc);
+            intl::segmenter::Segments::init(self, mc);
+            intl::segmenter::SegmentIterator::init(self, mc);
+            intl::PluralRules::init(self, mc);
+            intl::NumberFormat::init(self, mc);
         }
 
         #[cfg(feature = "temporal")]
         {
-            temporal::Temporal::init(self);
-            temporal::Now::init(self);
-            temporal::Instant::init(self);
-            temporal::Duration::init(self);
-            temporal::PlainDate::init(self);
-            temporal::PlainTime::init(self);
-            temporal::PlainDateTime::init(self);
-            temporal::PlainMonthDay::init(self);
-            temporal::PlainYearMonth::init(self);
-            temporal::ZonedDateTime::init(self);
+            temporal::Temporal::init(self, mc);
+            temporal::Now::init(self, mc);
+            temporal::Instant::init(self, mc);
+            temporal::Duration::init(self, mc);
+            temporal::PlainDate::init(self, mc);
+            temporal::PlainTime::init(self, mc);
+            temporal::PlainDateTime::init(self, mc);
+            temporal::PlainMonthDay::init(self, mc);
+            temporal::PlainYearMonth::init(self, mc);
+            temporal::ZonedDateTime::init(self, mc);
         }
     }
 }
diff --git a/core/engine/src/builtins/number/globals.rs b/core/engine/src/builtins/number/globals.rs
index 39c8c92b611..a40be6e03f2 100644
--- a/core/engine/src/builtins/number/globals.rs
+++ b/core/engine/src/builtins/number/globals.rs
@@ -36,8 +36,8 @@ fn is_finite(_: &JsValue, args: &[JsValue], context: &mut Context) -> JsResult<J
 pub(crate) struct IsFinite;
 
 impl IntrinsicObject for IsFinite {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::callable_with_intrinsic::<Self>(realm, is_finite)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::callable_with_intrinsic::<Self>(realm, is_finite, mc)
             .name(Self::NAME)
             .length(1)
             .build();
@@ -78,8 +78,8 @@ pub(crate) fn is_nan(_: &JsValue, args: &[JsValue], context: &mut Context) -> Js
 pub(crate) struct IsNaN;
 
 impl IntrinsicObject for IsNaN {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::callable_with_intrinsic::<Self>(realm, is_nan)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::callable_with_intrinsic::<Self>(realm, is_nan, mc)
             .name(Self::NAME)
             .length(1)
             .build();
@@ -267,8 +267,8 @@ pub(crate) fn parse_int(_: &JsValue, args: &[JsValue], context: &mut Context) ->
 pub(crate) struct ParseInt;
 
 impl IntrinsicObject for ParseInt {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::callable_with_intrinsic::<Self>(realm, parse_int)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::callable_with_intrinsic::<Self>(realm, parse_int, mc)
             .name(Self::NAME)
             .length(2)
             .build();
@@ -383,8 +383,8 @@ pub(crate) fn parse_float(
 pub(crate) struct ParseFloat;
 
 impl IntrinsicObject for ParseFloat {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::callable_with_intrinsic::<Self>(realm, parse_float)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::callable_with_intrinsic::<Self>(realm, parse_float, mc)
             .name(Self::NAME)
             .length(1)
             .build();
diff --git a/core/engine/src/builtins/number/mod.rs b/core/engine/src/builtins/number/mod.rs
index b4a0ad6a9b8..e6414927829 100644
--- a/core/engine/src/builtins/number/mod.rs
+++ b/core/engine/src/builtins/number/mod.rs
@@ -47,10 +47,10 @@ const BUF_SIZE: usize = 2200;
 pub(crate) struct Number;
 
 impl IntrinsicObject for Number {
-    fn init(realm: &Realm) {
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
         let attribute = Attribute::READONLY | Attribute::NON_ENUMERABLE | Attribute::PERMANENT;
 
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .static_property(js_string!("EPSILON"), f64::EPSILON, attribute)
             .static_property(
                 js_string!("MAX_SAFE_INTEGER"),
@@ -126,8 +126,12 @@ impl BuiltInConstructor for Number {
         }
         let prototype =
             get_prototype_from_constructor(new_target, StandardConstructors::number, context)?;
-        let this =
-            JsObject::from_proto_and_data_with_shared_shape(context.root_shape(), prototype, data);
+        let this = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
+            context.root_shape(),
+            prototype,
+            data,
+        );
         Ok(this.into())
     }
 }
diff --git a/core/engine/src/builtins/object/for_in_iterator.rs b/core/engine/src/builtins/object/for_in_iterator.rs
index 980d772c0c4..dfeac3601e1 100644
--- a/core/engine/src/builtins/object/for_in_iterator.rs
+++ b/core/engine/src/builtins/object/for_in_iterator.rs
@@ -58,17 +58,21 @@ impl ForInIterator {
         context: &Context,
     ) -> (JsObject, JsValue) {
         let iterator = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             context.intrinsics().constructors().iterator().prototype(),
             Self::new(object),
         )
         .upcast();
 
-        let next_method =
-            FunctionObjectBuilder::new(context.realm(), NativeFunction::from_fn_ptr(Self::next))
-                .name(js_string!("next"))
-                .length(0)
-                .build();
+        let next_method = FunctionObjectBuilder::new(
+            context.realm(),
+            context.gc_collector(),
+            NativeFunction::from_fn_ptr(Self::next),
+        )
+        .name(js_string!("next"))
+        .length(0)
+        .build();
 
         (iterator, next_method.into())
     }
diff --git a/core/engine/src/builtins/object/mod.rs b/core/engine/src/builtins/object/mod.rs
index 1947101550a..8872a4c2815 100644
--- a/core/engine/src/builtins/object/mod.rs
+++ b/core/engine/src/builtins/object/mod.rs
@@ -48,17 +48,17 @@ mod tests;
 pub struct OrdinaryObject;
 
 impl IntrinsicObject for OrdinaryObject {
-    fn init(realm: &Realm) {
-        let legacy_proto_getter = BuiltInBuilder::callable(realm, Self::legacy_proto_getter)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        let legacy_proto_getter = BuiltInBuilder::callable(realm, Self::legacy_proto_getter, mc)
             .name(js_string!("get __proto__"))
             .build();
 
-        let legacy_setter_proto = BuiltInBuilder::callable(realm, Self::legacy_proto_setter)
+        let legacy_setter_proto = BuiltInBuilder::callable(realm, Self::legacy_proto_setter, mc)
             .name(js_string!("set __proto__"))
             .length(1)
             .build();
 
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .inherits(None)
             .accessor(
                 js_string!("__proto__"),
@@ -172,6 +172,7 @@ impl BuiltInConstructor for OrdinaryObject {
             let prototype =
                 get_prototype_from_constructor(new_target, StandardConstructors::object, context)?;
             let object = JsObject::from_proto_and_data_with_shared_shape(
+                context.gc_collector(),
                 context.root_shape(),
                 prototype,
                 OrdinaryObject,
@@ -183,7 +184,7 @@ impl BuiltInConstructor for OrdinaryObject {
 
         // 2. If value is undefined or null, return OrdinaryObjectCreate(%Object.prototype%).
         if value.is_null_or_undefined() {
-            Ok(JsObject::with_object_proto(context.intrinsics()).into())
+            Ok(JsObject::with_object_proto(context.gc_collector(), context.intrinsics()).into())
         } else {
             // 3. Return ! ToObject(value).
             value.to_object(context).map(JsValue::from)
@@ -440,7 +441,7 @@ impl OrdinaryObject {
         }
     }
 
-    /// `Object.create( proto, [propertiesObject] )`
+    /// `Object.create( context.gc_collector(), proto, [propertiesObject] )`
     ///
     /// Creates a new object from the provided prototype.
     ///
@@ -457,6 +458,7 @@ impl OrdinaryObject {
         let obj = match prototype.variant() {
             JsVariant::Object(_) | JsVariant::Null => {
                 JsObject::from_proto_and_data_with_shared_shape(
+                    context.gc_collector(),
                     context.root_shape(),
                     prototype.as_object(),
                     OrdinaryObject,
@@ -532,7 +534,7 @@ impl OrdinaryObject {
             obj.__own_property_keys__(&mut InternalMethodPropertyContext::new(context))?;
 
         // 3. Let descriptors be OrdinaryObjectCreate(%Object.prototype%).
-        let descriptors = JsObject::with_object_proto(context.intrinsics());
+        let descriptors = JsObject::with_object_proto(context.gc_collector(), context.intrinsics());
 
         // 4. For each element key of ownKeys, do
         for key in own_keys {
@@ -573,7 +575,7 @@ impl OrdinaryObject {
 
         // 2. Let obj be ! OrdinaryObjectCreate(%Object.prototype%).
         // 3. Assert: obj is an extensible ordinary object with no own properties.
-        let obj = JsObject::with_object_proto(context.intrinsics());
+        let obj = JsObject::with_object_proto(context.gc_collector(), context.intrinsics());
 
         // 4. If Desc has a [[Value]] field, then
         if let Some(value) = desc.value() {
@@ -1299,12 +1301,13 @@ impl OrdinaryObject {
 
         // 2. Let obj be ! OrdinaryObjectCreate(%Object.prototype%).
         // 3. Assert: obj is an extensible ordinary object with no own properties.
-        let obj = JsObject::with_object_proto(context.intrinsics());
+        let obj = JsObject::with_object_proto(context.gc_collector(), context.intrinsics());
 
         // 4. Let closure be a new Abstract Closure with parameters (key, value) that captures
         // obj and performs the following steps when called:
         let closure = FunctionObjectBuilder::new(
             context.realm(),
+            context.gc_collector(),
             NativeFunction::from_copy_closure_with_captures(
                 |_, args, obj, context| {
                     let key = args.get_or_undefined(0);
@@ -1413,7 +1416,7 @@ impl OrdinaryObject {
         }
 
         // 2. Let obj be OrdinaryObjectCreate(null).
-        let obj = JsObject::with_null_proto();
+        let obj = JsObject::with_null_proto(context.gc_collector());
 
         // 3. For each Record { [[Key]], [[Elements]] } g of groups, do
         for (key, elements) in groups {
diff --git a/core/engine/src/builtins/options.rs b/core/engine/src/builtins/options.rs
index ba5d805874f..912a5c33e12 100644
--- a/core/engine/src/builtins/options.rs
+++ b/core/engine/src/builtins/options.rs
@@ -74,12 +74,15 @@ pub(crate) fn get_option<T: OptionType>(
 /// default empty `JsObject`. It throws a `TypeError` if `options` is not undefined and not a `JsObject`.
 ///
 /// [spec]: https://tc39.es/ecma402/#sec-getoptionsobject
-pub(crate) fn get_options_object(options: &JsValue) -> JsResult<JsObject> {
+pub(crate) fn get_options_object(
+    options: &JsValue,
+    mc: &boa_gc::MutationContext<'static, '_>,
+) -> JsResult<JsObject> {
     match options.variant() {
         // If options is undefined, then
         JsVariant::Undefined => {
             // a. Return OrdinaryObjectCreate(null).
-            Ok(JsObject::with_null_proto())
+            Ok(JsObject::with_null_proto(mc))
         }
         // 2. If Type(options) is Object, then
         JsVariant::Object(obj) => {
diff --git a/core/engine/src/builtins/promise/mod.rs b/core/engine/src/builtins/promise/mod.rs
index 84cc6a0c058..6d7d2c1c76c 100644
--- a/core/engine/src/builtins/promise/mod.rs
+++ b/core/engine/src/builtins/promise/mod.rs
@@ -252,6 +252,7 @@ impl PromiseCapability {
         // 5. Let executor be CreateBuiltinFunction(executorClosure, 2, "", « »).
         let executor = FunctionObjectBuilder::new(
             context.realm(),
+            context.gc_collector(),
             NativeFunction::from_copy_closure_with_captures(
                 |_this, args: &[JsValue], captures, _| {
                     let mut promise_capability = captures.borrow_mut();
@@ -338,12 +339,12 @@ impl PromiseCapability {
 }
 
 impl IntrinsicObject for Promise {
-    fn init(realm: &Realm) {
-        let get_species = BuiltInBuilder::callable(realm, Self::get_species)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        let get_species = BuiltInBuilder::callable(realm, Self::get_species, mc)
             .name(js_string!("get [Symbol.species]"))
             .build();
 
-        let builder = BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        let builder = BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .static_method(Self::all, js_string!("all"), 1)
             .static_method(Self::all_settled, js_string!("allSettled"), 1)
             .static_method(Self::any, js_string!("any"), 1)
@@ -422,6 +423,7 @@ impl BuiltInConstructor for Promise {
             get_prototype_from_constructor(new_target, StandardConstructors::promise, context)?;
 
         let promise = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             promise,
             // 4. Set promise.[[PromiseState]] to pending.
@@ -556,6 +558,7 @@ impl Promise {
         // 5. Perform ! CreateDataPropertyOrThrow(obj, "resolve", promiseCapability.[[Resolve]]).
         // 6. Perform ! CreateDataPropertyOrThrow(obj, "reject", promiseCapability.[[Reject]]).
         let obj = context.intrinsics().templates().with_resolvers().create(
+            context.gc_collector(),
             OrdinaryObject,
             vec![promise.into(), resolve.into(), reject.into()],
         );
@@ -680,6 +683,7 @@ impl Promise {
             // l. Set onFulfilled.[[RemainingElements]] to remainingElementsCount.
             let on_fulfilled = FunctionObjectBuilder::new(
                 context.realm(),
+                context.gc_collector(),
                 NativeFunction::from_copy_closure_with_captures(
                     |_, args, captures, context| {
                         // https://tc39.es/ecma262/#sec-promise.all-resolve-element-functions
@@ -898,6 +902,7 @@ impl Promise {
             // m. Set onFulfilled.[[RemainingElements]] to remainingElementsCount.
             let on_fulfilled = FunctionObjectBuilder::new(
                 context.realm(),
+                context.gc_collector(),
                 NativeFunction::from_copy_closure_with_captures(
                     |_, args, captures, context| {
                         // https://tc39.es/ecma262/#sec-promise.allsettled-resolve-element-functions
@@ -919,7 +924,10 @@ impl Promise {
                         // 8. Let remainingElementsCount be F.[[RemainingElements]].
 
                         // 9. Let obj be OrdinaryObjectCreate(%Object.prototype%).
-                        let obj = JsObject::with_object_proto(context.intrinsics());
+                        let obj = JsObject::with_object_proto(
+                            context.gc_collector(),
+                            context.intrinsics(),
+                        );
 
                         // 10. Perform ! CreateDataPropertyOrThrow(obj, "status", "fulfilled").
                         obj.create_data_property_or_throw(
@@ -988,6 +996,7 @@ impl Promise {
             // u. Set onRejected.[[RemainingElements]] to remainingElementsCount.
             let on_rejected = FunctionObjectBuilder::new(
                 context.realm(),
+                context.gc_collector(),
                 NativeFunction::from_copy_closure_with_captures(
                     |_, args, captures, context| {
                         // https://tc39.es/ecma262/#sec-promise.allsettled-reject-element-functions
@@ -1009,7 +1018,10 @@ impl Promise {
                         // 8. Let remainingElementsCount be F.[[RemainingElements]].
 
                         // 9. Let obj be OrdinaryObjectCreate(%Object.prototype%).
-                        let obj = JsObject::with_object_proto(context.intrinsics());
+                        let obj = JsObject::with_object_proto(
+                            context.gc_collector(),
+                            context.intrinsics(),
+                        );
 
                         // 10. Perform ! CreateDataPropertyOrThrow(obj, "status", "rejected").
                         obj.create_data_property_or_throw(
@@ -1272,6 +1284,7 @@ impl Promise {
                 // vi. Let onFulfilled be a new Abstract Closure...
                 let on_fulfilled = FunctionObjectBuilder::new(
                     context.realm(),
+                    context.gc_collector(),
                     NativeFunction::from_copy_closure_with_captures(
                         |_, args, captures, context| {
                             // 1. If alreadyCalled.[[Value]] is true, return undefined.
@@ -1291,7 +1304,10 @@ impl Promise {
                             } else {
                                 // 4. Else (variant is all-settled)
                                 // a. Let obj be OrdinaryObjectCreate(%Object.prototype%).
-                                let obj = JsObject::with_object_proto(context.intrinsics());
+                                let obj = JsObject::with_object_proto(
+                                    context.gc_collector(),
+                                    context.intrinsics(),
+                                );
                                 // b. Perform ! CreateDataPropertyOrThrow(obj, "status", "fulfilled").
                                 obj.create_data_property_or_throw(
                                     js_string!("status"),
@@ -1354,6 +1370,7 @@ impl Promise {
                     // Else (variant is all-settled), let onRejected be a new Abstract Closure...
                     let on_rejected_fn = FunctionObjectBuilder::new(
                         context.realm(),
+                        context.gc_collector(),
                         NativeFunction::from_copy_closure_with_captures(
                             |_, args, captures, context| {
                                 // 1. If alreadyCalled.[[Value]] is true, return undefined.
@@ -1367,7 +1384,10 @@ impl Promise {
                                 let x = args.get_or_undefined(0).clone();
 
                                 // 3. Let obj be OrdinaryObjectCreate(%Object.prototype%).
-                                let obj = JsObject::with_object_proto(context.intrinsics());
+                                let obj = JsObject::with_object_proto(
+                                    context.gc_collector(),
+                                    context.intrinsics(),
+                                );
                                 // 4. Perform ! CreateDataPropertyOrThrow(obj, "status", "rejected").
                                 obj.create_data_property_or_throw(
                                     js_string!("status"),
@@ -1573,6 +1593,7 @@ impl Promise {
             // l. Set onRejected.[[RemainingElements]] to remainingElementsCount.
             let on_rejected = FunctionObjectBuilder::new(
                 context.realm(),
+                context.gc_collector(),
                 NativeFunction::from_copy_closure_with_captures(
                     |_, args, captures, context| {
                         // https://tc39.es/ecma262/#sec-promise.any-reject-element-functions
@@ -2006,6 +2027,7 @@ impl Promise {
         // a. Let thenFinallyClosure be a new Abstract Closure with parameters (value) that captures onFinally and C and performs the following steps when called:
         let then_finally_closure = FunctionObjectBuilder::new(
             context.realm(),
+            context.gc_collector(),
             NativeFunction::from_copy_closure_with_captures(
                 |_this, args, captures, context| {
                     /// Capture object for the abstract `returnValue` closure.
@@ -2027,6 +2049,7 @@ impl Promise {
                     // iii. Let returnValue be a new Abstract Closure with no parameters that captures value and performs the following steps when called:
                     let return_value = FunctionObjectBuilder::new(
                         context.realm(),
+                        context.gc_collector(),
                         NativeFunction::from_copy_closure_with_captures(
                             |_this, _args, captures, _context| {
                                 // 1. Return value.
@@ -2057,6 +2080,7 @@ impl Promise {
         // c. Let catchFinallyClosure be a new Abstract Closure with parameters (reason) that captures onFinally and C and performs the following steps when called:
         let catch_finally_closure = FunctionObjectBuilder::new(
             context.realm(),
+            context.gc_collector(),
             NativeFunction::from_copy_closure_with_captures(
                 |_this, args, captures, context| {
                     /// Capture object for the abstract `throwReason` closure.
@@ -2078,6 +2102,7 @@ impl Promise {
                     // iii. Let throwReason be a new Abstract Closure with no parameters that captures reason and performs the following steps when called:
                     let throw_reason = FunctionObjectBuilder::new(
                         context.realm(),
+                        context.gc_collector(),
                         NativeFunction::from_copy_closure_with_captures(
                             |_this, _args, captures, _context| {
                                 // 1. Return ThrowCompletion(reason).
@@ -2452,6 +2477,7 @@ impl Promise {
         // 4. Let resolve be CreateBuiltinFunction(stepsResolve, lengthResolve, "", « [[Promise]], [[AlreadyResolved]] »).
         let resolve = FunctionObjectBuilder::new(
             context.realm(),
+            context.gc_collector(),
             NativeFunction::from_copy_closure_with_captures(
                 |_this, args, captures, context| {
                     // https://tc39.es/ecma262/#sec-promise-resolve-functions
@@ -2549,6 +2575,7 @@ impl Promise {
         // 9. Let reject be CreateBuiltinFunction(stepsReject, lengthReject, "", « [[Promise]], [[AlreadyResolved]] »).
         let reject = FunctionObjectBuilder::new(
             context.realm(),
+            context.gc_collector(),
             NativeFunction::from_copy_closure_with_captures(
                 |_this, args, captures, context| {
                     // https://tc39.es/ecma262/#sec-promise-reject-functions
@@ -2761,7 +2788,7 @@ fn create_keyed_result_object(
     debug_assert_eq!(keys.len(), values.len());
 
     // 2. Let obj be OrdinaryObjectCreate(null).
-    let obj = JsObject::with_null_proto();
+    let obj = JsObject::with_null_proto(context.gc_collector());
 
     // 3. For each integer i such that 0 ≤ i < the number of elements in keys, in ascending order, do
     for (key, value) in keys.iter().zip(values.iter()) {
diff --git a/core/engine/src/builtins/proxy/mod.rs b/core/engine/src/builtins/proxy/mod.rs
index a86155e2421..4b7c4d5e27c 100644
--- a/core/engine/src/builtins/proxy/mod.rs
+++ b/core/engine/src/builtins/proxy/mod.rs
@@ -87,8 +87,8 @@ impl JsData for Proxy {
 }
 
 impl IntrinsicObject for Proxy {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .static_method(Self::revocable, js_string!("revocable"), 2)
             .build_without_prototype();
     }
@@ -181,6 +181,7 @@ impl Proxy {
         // 6. Set P.[[ProxyTarget]] to target.
         // 7. Set P.[[ProxyHandler]] to handler.
         let p = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             context.intrinsics().constructors().object().prototype(),
             Self::new(target.clone(), handler.clone()),
@@ -215,7 +216,7 @@ impl Proxy {
             },
             GcRefCell::new(Some(proxy)),
         )
-        .to_js_function(context.realm())
+        .to_js_function(context.realm(), context.gc_collector())
     }
 
     /// `28.2.2.1 Proxy.revocable ( target, handler )`
@@ -232,7 +233,7 @@ impl Proxy {
         let revoker = Self::revoker(p.clone(), context);
 
         // 5. Let result be ! OrdinaryObjectCreate(%Object.prototype%).
-        let result = JsObject::with_object_proto(context.intrinsics());
+        let result = JsObject::with_object_proto(context.gc_collector(), context.intrinsics());
 
         // 6. Perform ! CreateDataPropertyOrThrow(result, "proxy", p).
         result
diff --git a/core/engine/src/builtins/reflect/mod.rs b/core/engine/src/builtins/reflect/mod.rs
index be57983f920..2c1e21e5491 100644
--- a/core/engine/src/builtins/reflect/mod.rs
+++ b/core/engine/src/builtins/reflect/mod.rs
@@ -33,10 +33,10 @@ mod tests;
 pub(crate) struct Reflect;
 
 impl IntrinsicObject for Reflect {
-    fn init(realm: &Realm) {
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
         let to_string_tag = JsSymbol::to_string_tag();
 
-        BuiltInBuilder::with_intrinsic::<Self>(realm)
+        BuiltInBuilder::with_intrinsic::<Self>(realm, mc)
             .static_method(Self::apply, js_string!("apply"), 3)
             .static_method(Self::construct, js_string!("construct"), 2)
             .static_method(Self::define_property, js_string!("defineProperty"), 3)
diff --git a/core/engine/src/builtins/regexp/mod.rs b/core/engine/src/builtins/regexp/mod.rs
index 037eed6eb19..5b6b97f8787 100644
--- a/core/engine/src/builtins/regexp/mod.rs
+++ b/core/engine/src/builtins/regexp/mod.rs
@@ -60,44 +60,44 @@ impl RegExp {
 }
 
 impl IntrinsicObject for RegExp {
-    fn init(realm: &Realm) {
-        let get_species = BuiltInBuilder::callable(realm, Self::get_species)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        let get_species = BuiltInBuilder::callable(realm, Self::get_species, mc)
             .name(js_string!("get [Symbol.species]"))
             .build();
 
         let flag_attributes = Attribute::CONFIGURABLE | Attribute::NON_ENUMERABLE;
 
-        let get_has_indices = BuiltInBuilder::callable(realm, Self::get_has_indices)
+        let get_has_indices = BuiltInBuilder::callable(realm, Self::get_has_indices, mc)
             .name(js_string!("get hasIndices"))
             .build();
-        let get_global = BuiltInBuilder::callable(realm, Self::get_global)
+        let get_global = BuiltInBuilder::callable(realm, Self::get_global, mc)
             .name(js_string!("get global"))
             .build();
-        let get_ignore_case = BuiltInBuilder::callable(realm, Self::get_ignore_case)
+        let get_ignore_case = BuiltInBuilder::callable(realm, Self::get_ignore_case, mc)
             .name(js_string!("get ignoreCase"))
             .build();
-        let get_multiline = BuiltInBuilder::callable(realm, Self::get_multiline)
+        let get_multiline = BuiltInBuilder::callable(realm, Self::get_multiline, mc)
             .name(js_string!("get multiline"))
             .build();
-        let get_dot_all = BuiltInBuilder::callable(realm, Self::get_dot_all)
+        let get_dot_all = BuiltInBuilder::callable(realm, Self::get_dot_all, mc)
             .name(js_string!("get dotAll"))
             .build();
-        let get_unicode = BuiltInBuilder::callable(realm, Self::get_unicode)
+        let get_unicode = BuiltInBuilder::callable(realm, Self::get_unicode, mc)
             .name(js_string!("get unicode"))
             .build();
-        let get_unicode_sets = BuiltInBuilder::callable(realm, Self::get_unicode_sets)
+        let get_unicode_sets = BuiltInBuilder::callable(realm, Self::get_unicode_sets, mc)
             .name(js_string!("get unicodeSets"))
             .build();
-        let get_sticky = BuiltInBuilder::callable(realm, Self::get_sticky)
+        let get_sticky = BuiltInBuilder::callable(realm, Self::get_sticky, mc)
             .name(js_string!("get sticky"))
             .build();
-        let get_flags = BuiltInBuilder::callable(realm, Self::get_flags)
+        let get_flags = BuiltInBuilder::callable(realm, Self::get_flags, mc)
             .name(js_string!("get flags"))
             .build();
-        let get_source = BuiltInBuilder::callable(realm, Self::get_source)
+        let get_source = BuiltInBuilder::callable(realm, Self::get_source, mc)
             .name(js_string!("get source"))
             .build();
-        let regexp = BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        let regexp = BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .static_method(Self::escape, js_string!("escape"), 1)
             .static_accessor(
                 JsSymbol::species(),
@@ -425,14 +425,14 @@ impl RegExp {
                 .templates()
                 .regexp_without_proto()
                 .clone();
-            template.set_prototype(prototype);
-            template.create(regexp, vec![0.into()])
+            template.set_prototype(context.gc_collector(), prototype);
+            template.create(context.gc_collector(), regexp, vec![0.into()])
         } else {
-            context
-                .intrinsics()
-                .templates()
-                .regexp()
-                .create(regexp, vec![0.into()])
+            context.intrinsics().templates().regexp().create(
+                context.gc_collector(),
+                regexp,
+                vec![0.into()],
+            )
         };
 
         // 23. Return obj.
@@ -1270,8 +1270,8 @@ impl RegExp {
         #[allow(clippy::if_not_else)]
         let (groups, group_names) = if !named_groups.clone().is_empty() {
             // a. Let groups be OrdinaryObjectCreate(null).
-            let groups = JsObject::with_null_proto();
-            let group_names = JsObject::with_null_proto();
+            let groups = JsObject::with_null_proto(context.gc_collector());
+            let group_names = JsObject::with_null_proto(context.gc_collector());
 
             // e. If the ith capture of R was defined with a GroupName, then
             // i. Let s be the CapturingGroupName of that GroupName.
diff --git a/core/engine/src/builtins/regexp/regexp_string_iterator.rs b/core/engine/src/builtins/regexp/regexp_string_iterator.rs
index 8d20e1366ac..0e72a55a759 100644
--- a/core/engine/src/builtins/regexp/regexp_string_iterator.rs
+++ b/core/engine/src/builtins/regexp/regexp_string_iterator.rs
@@ -40,8 +40,8 @@ pub(crate) struct RegExpStringIterator {
 }
 
 impl IntrinsicObject for RegExpStringIterator {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::with_intrinsic::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::with_intrinsic::<Self>(realm, mc)
             .prototype(realm.intrinsics().constructors().iterator().prototype())
             .static_method(Self::next, js_string!("next"), 0)
             .static_property(
@@ -95,6 +95,7 @@ impl RegExpStringIterator {
         // 5. Return ! CreateIteratorFromClosure(closure, "%RegExpStringIteratorPrototype%", %RegExpStringIteratorPrototype%).
 
         let regexp_string_iterator = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             context
                 .intrinsics()
diff --git a/core/engine/src/builtins/set/mod.rs b/core/engine/src/builtins/set/mod.rs
index 9052886b924..869829fffbb 100644
--- a/core/engine/src/builtins/set/mod.rs
+++ b/core/engine/src/builtins/set/mod.rs
@@ -123,20 +123,20 @@ impl IntrinsicObject for Set {
     fn get(intrinsics: &Intrinsics) -> JsObject {
         Self::STANDARD_CONSTRUCTOR(intrinsics.constructors()).constructor()
     }
-    fn init(realm: &Realm) {
-        let get_species = BuiltInBuilder::callable(realm, Self::get_species)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        let get_species = BuiltInBuilder::callable(realm, Self::get_species, mc)
             .name(js_string!("get [Symbol.species]"))
             .build();
 
-        let size_getter = BuiltInBuilder::callable(realm, Self::size_getter)
+        let size_getter = BuiltInBuilder::callable(realm, Self::size_getter, mc)
             .name(js_string!("get size"))
             .build();
 
-        let values_function = BuiltInBuilder::callable(realm, Self::values)
+        let values_function = BuiltInBuilder::callable(realm, Self::values, mc)
             .name(js_string!("values"))
             .build();
 
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .static_accessor(
                 JsSymbol::species(),
                 Some(get_species),
@@ -221,6 +221,7 @@ impl BuiltInConstructor for Set {
         let prototype =
             get_prototype_from_constructor(new_target, StandardConstructors::set, context)?;
         let set = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             prototype,
             OrderedSet::default(),
@@ -841,6 +842,7 @@ impl Set {
         //     9. Set result.[[SetData]] to resultSetData.
         //     10. Return result.
         Ok(JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             context.intrinsics().constructors().set().prototype(),
             result_set,
@@ -897,6 +899,7 @@ impl Set {
         // 9. Set result.[[SetData]] to resultSetData.
         // 10. Return result.
         Ok(JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             context.intrinsics().constructors().set().prototype(),
             result_set,
@@ -996,6 +999,7 @@ impl Set {
         // 8. Set result.[[SetData]] to resultSetData.
         // 9. Return result.
         Ok(JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             context.intrinsics().constructors().set().prototype(),
             result_set,
@@ -1093,6 +1097,7 @@ impl Set {
         // 8. Set result.[[SetData]] to resultSetData.
         // 9. Return result.
         Ok(JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             context.intrinsics().constructors().set().prototype(),
             result_set,
diff --git a/core/engine/src/builtins/set/set_iterator.rs b/core/engine/src/builtins/set/set_iterator.rs
index 03583591761..5872b9f0b94 100644
--- a/core/engine/src/builtins/set/set_iterator.rs
+++ b/core/engine/src/builtins/set/set_iterator.rs
@@ -52,8 +52,8 @@ pub(crate) struct SetIterator {
 }
 
 impl IntrinsicObject for SetIterator {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::with_intrinsic::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::with_intrinsic::<Self>(realm, mc)
             .prototype(realm.intrinsics().constructors().iterator().prototype())
             .static_method(Self::next, js_string!("next"), 0)
             .static_property(
@@ -84,6 +84,7 @@ impl SetIterator {
         context: &Context,
     ) -> JsValue {
         let set_iterator = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             context.intrinsics().objects().iterator_prototypes().set(),
             Self {
diff --git a/core/engine/src/builtins/string/mod.rs b/core/engine/src/builtins/string/mod.rs
index 9421b4654d7..ff26b4d10d8 100644
--- a/core/engine/src/builtins/string/mod.rs
+++ b/core/engine/src/builtins/string/mod.rs
@@ -62,13 +62,13 @@ pub(crate) enum Placement {
 pub(crate) struct String;
 
 impl IntrinsicObject for String {
-    fn init(realm: &Realm) {
-        let trim_start = BuiltInBuilder::callable(realm, Self::trim_start)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        let trim_start = BuiltInBuilder::callable(realm, Self::trim_start, mc)
             .length(0)
             .name(js_string!("trimStart"))
             .build();
 
-        let trim_end = BuiltInBuilder::callable(realm, Self::trim_end)
+        let trim_end = BuiltInBuilder::callable(realm, Self::trim_end, mc)
             .length(0)
             .name(js_string!("trimEnd"))
             .build();
@@ -80,7 +80,7 @@ impl IntrinsicObject for String {
         let trim_right = trim_end.clone();
 
         let attribute = Attribute::READONLY | Attribute::NON_ENUMERABLE | Attribute::PERMANENT;
-        let builder = BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        let builder = BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .property(js_string!("length"), 0, attribute)
             .property(
                 js_string!("trimStart"),
@@ -250,9 +250,13 @@ impl String {
         // 4. Set S.[[GetOwnProperty]] as specified in 10.4.3.1.
         // 5. Set S.[[DefineOwnProperty]] as specified in 10.4.3.2.
         // 6. Set S.[[OwnPropertyKeys]] as specified in 10.4.3.3.
-        let s =
-            JsObject::from_proto_and_data_with_shared_shape(context.root_shape(), prototype, value)
-                .upcast();
+        let s = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
+            context.root_shape(),
+            prototype,
+            value,
+        )
+        .upcast();
 
         // 8. Perform ! DefinePropertyOrThrow(S, "length", PropertyDescriptor { [[Value]]: 𝔽(length),
         // [[Writable]]: false, [[Enumerable]]: false, [[Configurable]]: false }).
diff --git a/core/engine/src/builtins/string/string_iterator.rs b/core/engine/src/builtins/string/string_iterator.rs
index 426ea9418fa..bf15695adfa 100644
--- a/core/engine/src/builtins/string/string_iterator.rs
+++ b/core/engine/src/builtins/string/string_iterator.rs
@@ -31,8 +31,8 @@ pub(crate) struct StringIterator {
 }
 
 impl IntrinsicObject for StringIterator {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::with_intrinsic::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::with_intrinsic::<Self>(realm, mc)
             .prototype(realm.intrinsics().constructors().iterator().prototype())
             .static_method(Self::next, js_string!("next"), 0)
             .static_property(
@@ -52,6 +52,7 @@ impl StringIterator {
     /// Create a new `StringIterator`.
     pub(crate) fn create_string_iterator(string: JsString, context: &mut Context) -> JsObject {
         JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             context
                 .intrinsics()
diff --git a/core/engine/src/builtins/symbol/mod.rs b/core/engine/src/builtins/symbol/mod.rs
index 91b87175b6d..232de88d863 100644
--- a/core/engine/src/builtins/symbol/mod.rs
+++ b/core/engine/src/builtins/symbol/mod.rs
@@ -93,7 +93,7 @@ impl GlobalSymbolRegistry {
 pub struct Symbol;
 
 impl IntrinsicObject for Symbol {
-    fn init(realm: &Realm) {
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
         let symbol_async_iterator = JsSymbol::async_iterator();
         let symbol_has_instance = JsSymbol::has_instance();
         let symbol_is_concat_spreadable = JsSymbol::is_concat_spreadable();
@@ -112,16 +112,16 @@ impl IntrinsicObject for Symbol {
 
         let attribute = Attribute::READONLY | Attribute::NON_ENUMERABLE | Attribute::PERMANENT;
 
-        let to_primitive = BuiltInBuilder::callable(realm, Self::to_primitive)
+        let to_primitive = BuiltInBuilder::callable(realm, Self::to_primitive, mc)
             .name(js_string!("[Symbol.toPrimitive]"))
             .length(1)
             .build();
 
-        let get_description = BuiltInBuilder::callable(realm, Self::get_description)
+        let get_description = BuiltInBuilder::callable(realm, Self::get_description, mc)
             .name(js_string!("get description"))
             .build();
 
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .static_method(Self::for_, js_string!("for"), 1)
             .static_method(Self::key_for, js_string!("keyFor"), 1)
             .static_property(
diff --git a/core/engine/src/builtins/temporal/duration/mod.rs b/core/engine/src/builtins/temporal/duration/mod.rs
index 7e0d8026ae7..a65c1e26d74 100644
--- a/core/engine/src/builtins/temporal/duration/mod.rs
+++ b/core/engine/src/builtins/temporal/duration/mod.rs
@@ -59,56 +59,56 @@ impl BuiltInObject for Duration {
 }
 
 impl IntrinsicObject for Duration {
-    fn init(realm: &Realm) {
-        let get_years = BuiltInBuilder::callable(realm, Self::get_years)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        let get_years = BuiltInBuilder::callable(realm, Self::get_years, mc)
             .name(js_string!("get Years"))
             .build();
 
-        let get_months = BuiltInBuilder::callable(realm, Self::get_months)
+        let get_months = BuiltInBuilder::callable(realm, Self::get_months, mc)
             .name(js_string!("get Months"))
             .build();
 
-        let get_weeks = BuiltInBuilder::callable(realm, Self::get_weeks)
+        let get_weeks = BuiltInBuilder::callable(realm, Self::get_weeks, mc)
             .name(js_string!("get Weeks"))
             .build();
 
-        let get_days = BuiltInBuilder::callable(realm, Self::get_days)
+        let get_days = BuiltInBuilder::callable(realm, Self::get_days, mc)
             .name(js_string!("get Days"))
             .build();
 
-        let get_hours = BuiltInBuilder::callable(realm, Self::get_hours)
+        let get_hours = BuiltInBuilder::callable(realm, Self::get_hours, mc)
             .name(js_string!("get Hours"))
             .build();
 
-        let get_minutes = BuiltInBuilder::callable(realm, Self::get_minutes)
+        let get_minutes = BuiltInBuilder::callable(realm, Self::get_minutes, mc)
             .name(js_string!("get Minutes"))
             .build();
 
-        let get_seconds = BuiltInBuilder::callable(realm, Self::get_seconds)
+        let get_seconds = BuiltInBuilder::callable(realm, Self::get_seconds, mc)
             .name(js_string!("get Seconds"))
             .build();
 
-        let get_milliseconds = BuiltInBuilder::callable(realm, Self::get_milliseconds)
+        let get_milliseconds = BuiltInBuilder::callable(realm, Self::get_milliseconds, mc)
             .name(js_string!("get Milliseconds"))
             .build();
 
-        let get_microseconds = BuiltInBuilder::callable(realm, Self::get_microseconds)
+        let get_microseconds = BuiltInBuilder::callable(realm, Self::get_microseconds, mc)
             .name(js_string!("get Microseconds"))
             .build();
 
-        let get_nanoseconds = BuiltInBuilder::callable(realm, Self::get_nanoseconds)
+        let get_nanoseconds = BuiltInBuilder::callable(realm, Self::get_nanoseconds, mc)
             .name(js_string!("get Nanoseconds"))
             .build();
 
-        let get_sign = BuiltInBuilder::callable(realm, Self::get_sign)
+        let get_sign = BuiltInBuilder::callable(realm, Self::get_sign, mc)
             .name(js_string!("get Sign"))
             .build();
 
-        let is_blank = BuiltInBuilder::callable(realm, Self::get_blank)
+        let is_blank = BuiltInBuilder::callable(realm, Self::get_blank, mc)
             .name(js_string!("get blank"))
             .build();
 
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .property(
                 JsSymbol::to_string_tag(),
                 StaticJsStrings::DURATION_TAG,
@@ -612,7 +612,7 @@ impl Duration {
         // 2. Set two to ? ToTemporalDuration(two).
         let two = to_temporal_duration(args.get_or_undefined(1), context)?;
         // 3. Let resolvedOptions be ? GetOptionsObject(options).
-        let options = get_options_object(args.get_or_undefined(2))?;
+        let options = get_options_object(args.get_or_undefined(2), context.gc_collector())?;
         // 4. Let relativeToRecord be ? GetTemporalRelativeToOption(resolvedOptions).
         let relative_to = get_relative_to_option(&options, context)?;
 
@@ -908,7 +908,7 @@ impl Duration {
             // a. Let paramString be roundTo.
             let param_string = param_string.clone();
             // b. Set roundTo to OrdinaryObjectCreate(null).
-            let new_round_to = JsObject::with_null_proto();
+            let new_round_to = JsObject::with_null_proto(context.gc_collector());
             // c. Perform ! CreateDataPropertyOrThrow(roundTo, "smallestUnit", paramString).
             new_round_to.create_data_property_or_throw(
                 js_string!("smallestUnit"),
@@ -919,7 +919,7 @@ impl Duration {
         } else {
             // 5. Else,
             // a. Set roundTo to ? GetOptionsObject(roundTo).
-            get_options_object(round_to_arg)?
+            get_options_object(round_to_arg, context.gc_collector())?
         };
 
         // NOTE: 6 & 7 unused in favor of `is_none()`.
@@ -1009,7 +1009,7 @@ impl Duration {
             JsVariant::String(param_string) => {
                 // a. Let paramString be totalOf.
                 // b. Set totalOf to OrdinaryObjectCreate(null).
-                let total_of = JsObject::with_null_proto();
+                let total_of = JsObject::with_null_proto(context.gc_collector());
                 // c. Perform ! CreateDataPropertyOrThrow(totalOf, "unit", paramString).
                 total_of.create_data_property_or_throw(
                     js_string!("unit"),
@@ -1021,7 +1021,7 @@ impl Duration {
             // 5. Else,
             _ => {
                 // a. Set totalOf to ? GetOptionsObject(totalOf).
-                get_options_object(total_of)?
+                get_options_object(total_of, context.gc_collector())?
             }
         };
 
@@ -1072,7 +1072,7 @@ impl Duration {
                 JsNativeError::typ().with_message("this value must be a Duration object.")
             })?;
 
-        let options = get_options_object(args.get_or_undefined(0))?;
+        let options = get_options_object(args.get_or_undefined(0), context.gc_collector())?;
         let precision = get_digits_option(&options, context)?;
         let rounding_mode =
             get_option::<RoundingMode>(&options, js_string!("roundingMode"), context)?;
@@ -1262,7 +1262,8 @@ pub(crate) fn create_temporal_duration(
     // 12. Set object.[[Microseconds]] to ℝ(𝔽(microseconds)).
     // 13. Set object.[[Nanoseconds]] to ℝ(𝔽(nanoseconds)).
 
-    let obj = JsObject::from_proto_and_data(prototype, Duration::new(inner));
+    let obj =
+        JsObject::from_proto_and_data(context.gc_collector(), prototype, Duration::new(inner));
     // 14. Return object.
     Ok(obj)
 }
diff --git a/core/engine/src/builtins/temporal/instant/mod.rs b/core/engine/src/builtins/temporal/instant/mod.rs
index 1a26d930893..9f254d545b2 100644
--- a/core/engine/src/builtins/temporal/instant/mod.rs
+++ b/core/engine/src/builtins/temporal/instant/mod.rs
@@ -61,16 +61,16 @@ impl BuiltInObject for Instant {
 }
 
 impl IntrinsicObject for Instant {
-    fn init(realm: &Realm) {
-        let get_millis = BuiltInBuilder::callable(realm, Self::get_epoch_milliseconds)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        let get_millis = BuiltInBuilder::callable(realm, Self::get_epoch_milliseconds, mc)
             .name(js_string!("get epochMilliseconds"))
             .build();
 
-        let get_nanos = BuiltInBuilder::callable(realm, Self::get_epoch_nanoseconds)
+        let get_nanos = BuiltInBuilder::callable(realm, Self::get_epoch_nanoseconds, mc)
             .name(js_string!("get epochNanoseconds"))
             .build();
 
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .property(
                 JsSymbol::to_string_tag(),
                 StaticJsStrings::INSTANT_TAG,
@@ -428,8 +428,10 @@ impl Instant {
         let other = to_temporal_instant(args.get_or_undefined(0), context)?;
 
         // Fetch the necessary options.
-        let settings =
-            get_difference_settings(&get_options_object(args.get_or_undefined(1))?, context)?;
+        let settings = get_difference_settings(
+            &get_options_object(args.get_or_undefined(1), context.gc_collector())?,
+            context,
+        )?;
         let result = instant.inner.until(&other, settings)?;
         create_temporal_duration(result, None, context).map(Into::into)
     }
@@ -462,8 +464,10 @@ impl Instant {
 
         // 3. Return ? DifferenceTemporalInstant(since, instant, other, options).
         let other = to_temporal_instant(args.get_or_undefined(0), context)?;
-        let settings =
-            get_difference_settings(&get_options_object(args.get_or_undefined(1))?, context)?;
+        let settings = get_difference_settings(
+            &get_options_object(args.get_or_undefined(1), context.gc_collector())?,
+            context,
+        )?;
         let result = instant.inner.since(&other, settings)?;
         create_temporal_duration(result, None, context).map(Into::into)
     }
@@ -506,7 +510,7 @@ impl Instant {
             // a. Let paramString be roundTo.
             let param_string = param_string.clone();
             // b. Set roundTo to OrdinaryObjectCreate(null).
-            let new_round_to = JsObject::with_null_proto();
+            let new_round_to = JsObject::with_null_proto(context.gc_collector());
             // c. Perform ! CreateDataPropertyOrThrow(roundTo, "smallestUnit", paramString).
             new_round_to.create_data_property_or_throw(
                 js_string!("smallestUnit"),
@@ -517,7 +521,7 @@ impl Instant {
         } else {
             // 5. Else,
             // a. Set roundTo to ? GetOptionsObject(roundTo).
-            get_options_object(round_to_arg)?
+            get_options_object(round_to_arg, context.gc_collector())?
         };
 
         // 6. NOTE: The following steps read options and perform independent validation in
@@ -624,7 +628,7 @@ impl Instant {
                     .with_message("the this object must be a Temporal.Instant object.")
             })?;
 
-        let options = get_options_object(args.get_or_undefined(0))?;
+        let options = get_options_object(args.get_or_undefined(0), context.gc_collector())?;
 
         let precision = get_digits_option(&options, context)?;
         let rounding_mode =
@@ -784,7 +788,7 @@ pub(crate) fn create_temporal_instant(
         get_prototype_from_constructor(&new_target, StandardConstructors::instant, context)?;
 
     // 4. Set object.[[Nanoseconds]] to epochNanoseconds.
-    let obj = JsObject::from_proto_and_data(proto, Instant::new(instant));
+    let obj = JsObject::from_proto_and_data(context.gc_collector(), proto, Instant::new(instant));
 
     // 5. Return object.
     Ok(obj.into())
diff --git a/core/engine/src/builtins/temporal/mod.rs b/core/engine/src/builtins/temporal/mod.rs
index 7ae6451d484..f0941b8e274 100644
--- a/core/engine/src/builtins/temporal/mod.rs
+++ b/core/engine/src/builtins/temporal/mod.rs
@@ -82,8 +82,8 @@ impl BuiltInObject for Temporal {
 }
 
 impl IntrinsicObject for Temporal {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::with_intrinsic::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::with_intrinsic::<Self>(realm, mc)
             .static_property(
                 JsSymbol::to_string_tag(),
                 Self::NAME,
diff --git a/core/engine/src/builtins/temporal/now.rs b/core/engine/src/builtins/temporal/now.rs
index 9737fd9e056..c5e09d76db6 100644
--- a/core/engine/src/builtins/temporal/now.rs
+++ b/core/engine/src/builtins/temporal/now.rs
@@ -39,13 +39,13 @@ pub struct Now;
 
 impl IntrinsicObject for Now {
     /// Initializes the `Temporal.Now` object.
-    fn init(realm: &Realm) {
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
         // is an ordinary object.
         // has a [[Prototype]] internal slot whose value is %Object.prototype%.
         // is not a function object.
         // does not have a [[Construct]] internal method; it cannot be used as a constructor with the new operator.
         // does not have a [[Call]] internal method; it cannot be invoked as a function.
-        BuiltInBuilder::with_intrinsic::<Self>(realm)
+        BuiltInBuilder::with_intrinsic::<Self>(realm, mc)
             .static_property(
                 JsSymbol::to_string_tag(),
                 StaticJsStrings::NOW_TAG,
diff --git a/core/engine/src/builtins/temporal/plain_date/mod.rs b/core/engine/src/builtins/temporal/plain_date/mod.rs
index e3a220ca78e..cebba525bfb 100644
--- a/core/engine/src/builtins/temporal/plain_date/mod.rs
+++ b/core/engine/src/builtins/temporal/plain_date/mod.rs
@@ -72,72 +72,72 @@ impl BuiltInObject for PlainDate {
 }
 
 impl IntrinsicObject for PlainDate {
-    fn init(realm: &Realm) {
-        let get_calendar_id = BuiltInBuilder::callable(realm, Self::get_calendar_id)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        let get_calendar_id = BuiltInBuilder::callable(realm, Self::get_calendar_id, mc)
             .name(js_string!("get calendarId"))
             .build();
 
-        let get_era = BuiltInBuilder::callable(realm, Self::get_era)
+        let get_era = BuiltInBuilder::callable(realm, Self::get_era, mc)
             .name(js_string!("get era"))
             .build();
 
-        let get_era_year = BuiltInBuilder::callable(realm, Self::get_era_year)
+        let get_era_year = BuiltInBuilder::callable(realm, Self::get_era_year, mc)
             .name(js_string!("get eraYear"))
             .build();
 
-        let get_year = BuiltInBuilder::callable(realm, Self::get_year)
+        let get_year = BuiltInBuilder::callable(realm, Self::get_year, mc)
             .name(js_string!("get year"))
             .build();
 
-        let get_month = BuiltInBuilder::callable(realm, Self::get_month)
+        let get_month = BuiltInBuilder::callable(realm, Self::get_month, mc)
             .name(js_string!("get month"))
             .build();
 
-        let get_month_code = BuiltInBuilder::callable(realm, Self::get_month_code)
+        let get_month_code = BuiltInBuilder::callable(realm, Self::get_month_code, mc)
             .name(js_string!("get monthCode"))
             .build();
 
-        let get_day = BuiltInBuilder::callable(realm, Self::get_day)
+        let get_day = BuiltInBuilder::callable(realm, Self::get_day, mc)
             .name(js_string!("get day"))
             .build();
 
-        let get_day_of_week = BuiltInBuilder::callable(realm, Self::get_day_of_week)
+        let get_day_of_week = BuiltInBuilder::callable(realm, Self::get_day_of_week, mc)
             .name(js_string!("get dayOfWeek"))
             .build();
 
-        let get_day_of_year = BuiltInBuilder::callable(realm, Self::get_day_of_year)
+        let get_day_of_year = BuiltInBuilder::callable(realm, Self::get_day_of_year, mc)
             .name(js_string!("get dayOfYear"))
             .build();
 
-        let get_week_of_year = BuiltInBuilder::callable(realm, Self::get_week_of_year)
+        let get_week_of_year = BuiltInBuilder::callable(realm, Self::get_week_of_year, mc)
             .name(js_string!("get weekOfYear"))
             .build();
 
-        let get_year_of_week = BuiltInBuilder::callable(realm, Self::get_year_of_week)
+        let get_year_of_week = BuiltInBuilder::callable(realm, Self::get_year_of_week, mc)
             .name(js_string!("get yearOfWeek"))
             .build();
 
-        let get_days_in_week = BuiltInBuilder::callable(realm, Self::get_days_in_week)
+        let get_days_in_week = BuiltInBuilder::callable(realm, Self::get_days_in_week, mc)
             .name(js_string!("get daysInWeek"))
             .build();
 
-        let get_days_in_month = BuiltInBuilder::callable(realm, Self::get_days_in_month)
+        let get_days_in_month = BuiltInBuilder::callable(realm, Self::get_days_in_month, mc)
             .name(js_string!("get daysInMonth"))
             .build();
 
-        let get_days_in_year = BuiltInBuilder::callable(realm, Self::get_days_in_year)
+        let get_days_in_year = BuiltInBuilder::callable(realm, Self::get_days_in_year, mc)
             .name(js_string!("get daysInYear"))
             .build();
 
-        let get_months_in_year = BuiltInBuilder::callable(realm, Self::get_months_in_year)
+        let get_months_in_year = BuiltInBuilder::callable(realm, Self::get_months_in_year, mc)
             .name(js_string!("get monthsInYear"))
             .build();
 
-        let get_in_leap_year = BuiltInBuilder::callable(realm, Self::get_in_leap_year)
+        let get_in_leap_year = BuiltInBuilder::callable(realm, Self::get_in_leap_year, mc)
             .name(js_string!("get inLeapYear"))
             .build();
 
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .property(
                 JsSymbol::to_string_tag(),
                 StaticJsStrings::PLAIN_DATE_TAG,
@@ -752,7 +752,10 @@ impl PlainDate {
 
         let object = item.as_object();
         if let Some(date) = object.as_ref().and_then(JsObject::downcast_ref::<Self>) {
-            let options = get_options_object(options.unwrap_or(&JsValue::undefined()))?;
+            let options = get_options_object(
+                options.unwrap_or(&JsValue::undefined()),
+                context.gc_collector(),
+            )?;
             let _ = get_option::<Overflow>(&options, js_string!("overflow"), context)?;
             return create_temporal_date(date.inner.clone(), None, context).map(Into::into);
         }
@@ -869,7 +872,7 @@ impl PlainDate {
         let duration = to_temporal_duration_record(args.get_or_undefined(0), context)?;
 
         // 4. Set options to ? GetOptionsObject(options).
-        let options = get_options_object(args.get_or_undefined(1))?;
+        let options = get_options_object(args.get_or_undefined(1), context.gc_collector())?;
 
         let overflow = get_option::<Overflow>(&options, js_string!("overflow"), context)?;
 
@@ -905,7 +908,7 @@ impl PlainDate {
         let duration = to_temporal_duration_record(args.get_or_undefined(0), context)?;
 
         // 4. Set options to ? GetOptionsObject(options).
-        let options = get_options_object(args.get_or_undefined(1))?;
+        let options = get_options_object(args.get_or_undefined(1), context.gc_collector())?;
         let overflow = get_option::<Overflow>(&options, js_string!("overflow"), context)?;
 
         // 5. Let negatedDuration be CreateNegatedTemporalDuration(duration).
@@ -954,7 +957,7 @@ impl PlainDate {
         let fields = to_calendar_fields(&partial_object, date.inner.calendar(), context)?;
 
         // 8. Let resolvedOptions be ? GetOptionsObject(options).
-        let options = get_options_object(args.get_or_undefined(1))?;
+        let options = get_options_object(args.get_or_undefined(1), context.gc_collector())?;
         // 9. Let overflow be ? GetTemporalOverflowOption(resolvedOptions).
         let overflow = get_option::<Overflow>(&options, js_string!("overflow"), context)?;
 
@@ -1018,7 +1021,7 @@ impl PlainDate {
         let other = to_temporal_date(args.get_or_undefined(0), None, context)?;
 
         // 3. Return ? DifferenceTemporalPlainDate(until, temporalDate, other, options).
-        let options = get_options_object(args.get_or_undefined(1))?;
+        let options = get_options_object(args.get_or_undefined(1), context.gc_collector())?;
         let settings = get_difference_settings(&options, context)?;
 
         create_temporal_duration(date.inner.until(&other, settings)?, None, context).map(Into::into)
@@ -1049,7 +1052,7 @@ impl PlainDate {
         // 3. Return ? DifferenceTemporalPlainDate(since, temporalDate, other, options).
         let other = to_temporal_date(args.get_or_undefined(0), None, context)?;
 
-        let options = get_options_object(args.get_or_undefined(1))?;
+        let options = get_options_object(args.get_or_undefined(1), context.gc_collector())?;
         let settings = get_difference_settings(&options, context)?;
 
         create_temporal_duration(date.inner.since(&other, settings)?, None, context).map(Into::into)
@@ -1204,7 +1207,7 @@ impl PlainDate {
                 JsNativeError::typ().with_message("the this object must be a PlainDate object.")
             })?;
 
-        let options = get_options_object(args.get_or_undefined(0))?;
+        let options = get_options_object(args.get_or_undefined(0), context.gc_collector())?;
         let display_calendar =
             get_option::<DisplayCalendar>(&options, js_string!("calendarName"), context)?
                 .unwrap_or(DisplayCalendar::Auto);
@@ -1302,7 +1305,8 @@ pub(crate) fn create_temporal_date(
     // 6. Set object.[[ISOMonth]] to isoMonth.
     // 7. Set object.[[ISODay]] to isoDay.
     // 8. Set object.[[Calendar]] to calendar.
-    let obj = JsObject::from_proto_and_data(prototype, PlainDate::new(inner));
+    let obj =
+        JsObject::from_proto_and_data(context.gc_collector(), prototype, PlainDate::new(inner));
 
     // 9. Return object.
     Ok(obj)
@@ -1326,11 +1330,11 @@ pub(crate) fn to_temporal_date(
     if let Some(object) = item.as_object() {
         // a. If item has an [[InitializedTemporalDate]] internal slot, then
         if let Some(date) = object.downcast_ref::<PlainDate>() {
-            let _options_obj = get_options_object(&options)?;
+            let _options_obj = get_options_object(&options, context.gc_collector())?;
             return Ok(date.inner.clone());
         // b. If item has an [[InitializedTemporalZonedDateTime]] internal slot, then
         } else if let Some(zdt) = object.downcast_ref::<ZonedDateTime>() {
-            let options_obj = get_options_object(&options)?;
+            let options_obj = get_options_object(&options, context.gc_collector())?;
             // i. Perform ? ToTemporalOverflow(options).
             let _overflow = get_option(&options_obj, js_string!("overflow"), context)?
                 .unwrap_or(Overflow::Constrain);
@@ -1341,7 +1345,7 @@ pub(crate) fn to_temporal_date(
             return Ok(zdt.inner.to_plain_date());
         // c. If item has an [[InitializedTemporalDateTime]] internal slot, then
         } else if let Some(dt) = object.downcast_ref::<PlainDateTime>() {
-            let options_obj = get_options_object(&options)?;
+            let options_obj = get_options_object(&options, context.gc_collector())?;
             // i. Perform ? ToTemporalOverflow(options).
             let _overflow = get_option(&options_obj, js_string!("overflow"), context)?
                 .unwrap_or(Overflow::Constrain);
@@ -1356,7 +1360,7 @@ pub(crate) fn to_temporal_date(
         // e. Let fields be ? PrepareCalendarFields(calendar, item, « year, month, month-code, day », «», «»).
         let partial = to_partial_date_record(&object, context)?;
         // f. Let resolvedOptions be ? GetOptionsObject(options).
-        let resolved_options = get_options_object(&options)?;
+        let resolved_options = get_options_object(&options, context.gc_collector())?;
         // g. Let overflow be ? GetTemporalOverflowOption(resolvedOptions).
         let overflow = get_option::<Overflow>(&resolved_options, js_string!("overflow"), context)?;
         // h. Let isoDate be ? CalendarDateFromFields(calendar, fields, overflow).
@@ -1381,7 +1385,7 @@ pub(crate) fn to_temporal_date(
     // 6. If calendar is empty, set calendar to "iso8601".
     // 7. Set calendar to ? CanonicalizeCalendar(calendar).
     // 8. Let resolvedOptions be ? GetOptionsObject(options).
-    let resolved_options = get_options_object(&options)?;
+    let resolved_options = get_options_object(&options, context.gc_collector())?;
     // 9. Perform ? GetTemporalOverflowOption(resolvedOptions).
     let _overflow = get_option::<Overflow>(&resolved_options, js_string!("overflow"), context)?
         .unwrap_or(Overflow::Constrain);
diff --git a/core/engine/src/builtins/temporal/plain_date_time/mod.rs b/core/engine/src/builtins/temporal/plain_date_time/mod.rs
index 4270df4f84e..bb8c8e6c8a6 100644
--- a/core/engine/src/builtins/temporal/plain_date_time/mod.rs
+++ b/core/engine/src/builtins/temporal/plain_date_time/mod.rs
@@ -75,96 +75,96 @@ impl BuiltInObject for PlainDateTime {
 }
 
 impl IntrinsicObject for PlainDateTime {
-    fn init(realm: &Realm) {
-        let get_calendar_id = BuiltInBuilder::callable(realm, Self::get_calendar_id)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        let get_calendar_id = BuiltInBuilder::callable(realm, Self::get_calendar_id, mc)
             .name(js_string!("get calendarId"))
             .build();
 
-        let get_era = BuiltInBuilder::callable(realm, Self::get_era)
+        let get_era = BuiltInBuilder::callable(realm, Self::get_era, mc)
             .name(js_string!("get era"))
             .build();
 
-        let get_era_year = BuiltInBuilder::callable(realm, Self::get_era_year)
+        let get_era_year = BuiltInBuilder::callable(realm, Self::get_era_year, mc)
             .name(js_string!("get eraYear"))
             .build();
 
-        let get_year = BuiltInBuilder::callable(realm, Self::get_year)
+        let get_year = BuiltInBuilder::callable(realm, Self::get_year, mc)
             .name(js_string!("get year"))
             .build();
 
-        let get_month = BuiltInBuilder::callable(realm, Self::get_month)
+        let get_month = BuiltInBuilder::callable(realm, Self::get_month, mc)
             .name(js_string!("get month"))
             .build();
 
-        let get_month_code = BuiltInBuilder::callable(realm, Self::get_month_code)
+        let get_month_code = BuiltInBuilder::callable(realm, Self::get_month_code, mc)
             .name(js_string!("get monthCode"))
             .build();
 
-        let get_day = BuiltInBuilder::callable(realm, Self::get_day)
+        let get_day = BuiltInBuilder::callable(realm, Self::get_day, mc)
             .name(js_string!("get day"))
             .build();
 
-        let get_hour = BuiltInBuilder::callable(realm, Self::get_hour)
+        let get_hour = BuiltInBuilder::callable(realm, Self::get_hour, mc)
             .name(js_string!("get hour"))
             .build();
 
-        let get_minute = BuiltInBuilder::callable(realm, Self::get_minute)
+        let get_minute = BuiltInBuilder::callable(realm, Self::get_minute, mc)
             .name(js_string!("get minute"))
             .build();
 
-        let get_second = BuiltInBuilder::callable(realm, Self::get_second)
+        let get_second = BuiltInBuilder::callable(realm, Self::get_second, mc)
             .name(js_string!("get second"))
             .build();
 
-        let get_millisecond = BuiltInBuilder::callable(realm, Self::get_millisecond)
+        let get_millisecond = BuiltInBuilder::callable(realm, Self::get_millisecond, mc)
             .name(js_string!("get millisecond"))
             .build();
 
-        let get_microsecond = BuiltInBuilder::callable(realm, Self::get_microsecond)
+        let get_microsecond = BuiltInBuilder::callable(realm, Self::get_microsecond, mc)
             .name(js_string!("get microsecond"))
             .build();
 
-        let get_nanosecond = BuiltInBuilder::callable(realm, Self::get_nanosecond)
+        let get_nanosecond = BuiltInBuilder::callable(realm, Self::get_nanosecond, mc)
             .name(js_string!("get nanosecond"))
             .build();
 
-        let get_day_of_week = BuiltInBuilder::callable(realm, Self::get_day_of_week)
+        let get_day_of_week = BuiltInBuilder::callable(realm, Self::get_day_of_week, mc)
             .name(js_string!("get dayOfWeek"))
             .build();
 
-        let get_day_of_year = BuiltInBuilder::callable(realm, Self::get_day_of_year)
+        let get_day_of_year = BuiltInBuilder::callable(realm, Self::get_day_of_year, mc)
             .name(js_string!("get dayOfYear"))
             .build();
 
-        let get_week_of_year = BuiltInBuilder::callable(realm, Self::get_week_of_year)
+        let get_week_of_year = BuiltInBuilder::callable(realm, Self::get_week_of_year, mc)
             .name(js_string!("get weekOfYear"))
             .build();
 
-        let get_year_of_week = BuiltInBuilder::callable(realm, Self::get_year_of_week)
+        let get_year_of_week = BuiltInBuilder::callable(realm, Self::get_year_of_week, mc)
             .name(js_string!("get yearOfWeek"))
             .build();
 
-        let get_days_in_week = BuiltInBuilder::callable(realm, Self::get_days_in_week)
+        let get_days_in_week = BuiltInBuilder::callable(realm, Self::get_days_in_week, mc)
             .name(js_string!("get daysInWeek"))
             .build();
 
-        let get_days_in_month = BuiltInBuilder::callable(realm, Self::get_days_in_month)
+        let get_days_in_month = BuiltInBuilder::callable(realm, Self::get_days_in_month, mc)
             .name(js_string!("get daysInMonth"))
             .build();
 
-        let get_days_in_year = BuiltInBuilder::callable(realm, Self::get_days_in_year)
+        let get_days_in_year = BuiltInBuilder::callable(realm, Self::get_days_in_year, mc)
             .name(js_string!("get daysInYear"))
             .build();
 
-        let get_months_in_year = BuiltInBuilder::callable(realm, Self::get_months_in_year)
+        let get_months_in_year = BuiltInBuilder::callable(realm, Self::get_months_in_year, mc)
             .name(js_string!("get monthsInYear"))
             .build();
 
-        let get_in_leap_year = BuiltInBuilder::callable(realm, Self::get_in_leap_year)
+        let get_in_leap_year = BuiltInBuilder::callable(realm, Self::get_in_leap_year, mc)
             .name(js_string!("get inLeapYear"))
             .build();
 
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .property(
                 JsSymbol::to_string_tag(),
                 StaticJsStrings::PLAIN_DATETIME_TAG,
@@ -1024,7 +1024,7 @@ impl PlainDateTime {
         let object = item.as_object();
         let dt = if let Some(pdt) = object.as_ref().and_then(JsObject::downcast_ref::<Self>) {
             // a. Perform ? GetTemporalOverflowOption(options).
-            let options = get_options_object(args.get_or_undefined(1))?;
+            let options = get_options_object(args.get_or_undefined(1), context.gc_collector())?;
             let _ = get_option::<Overflow>(&options, js_string!("overflow"), context)?;
             // b. Return ! CreateTemporalDateTime(item.[[ISOYear]], item.[[ISOMonth]],
             // item.[[ISODay]], item.[[ISOHour]], item.[[ISOMinute]], item.[[ISOSecond]],
@@ -1110,7 +1110,7 @@ impl PlainDateTime {
         // 13. Set fields to CalendarMergeFields(calendar, fields, partialDateTime).
         let fields = to_date_time_fields(&partial_object, dt.inner.calendar(), context)?;
         // 14. Let resolvedOptions be ? GetOptionsObject(options).
-        let options = get_options_object(args.get_or_undefined(1))?;
+        let options = get_options_object(args.get_or_undefined(1), context.gc_collector())?;
         // 15. Let overflow be ? GetTemporalOverflowOption(resolvedOptions).
         let overflow = get_option::<Overflow>(&options, js_string!("overflow"), context)?;
 
@@ -1202,7 +1202,7 @@ impl PlainDateTime {
         let duration = to_temporal_duration_record(args.get_or_undefined(0), context)?;
 
         // 4. Set options to ? GetOptionsObject(options).
-        let options = get_options_object(args.get_or_undefined(1))?;
+        let options = get_options_object(args.get_or_undefined(1), context.gc_collector())?;
         let overflow = get_option::<Overflow>(&options, js_string!("overflow"), context)?;
 
         // 5. Let calendarRec be ? CreateCalendarMethodsRecord(temporalDate.[[Calendar]], « date-add »).
@@ -1236,7 +1236,7 @@ impl PlainDateTime {
         let duration = to_temporal_duration_record(args.get_or_undefined(0), context)?;
 
         // 4. Set options to ? GetOptionsObject(options).
-        let options = get_options_object(args.get_or_undefined(1))?;
+        let options = get_options_object(args.get_or_undefined(1), context.gc_collector())?;
         let overflow = get_option::<Overflow>(&options, js_string!("overflow"), context)?;
 
         // 5. Let negatedDuration be CreateNegatedTemporalDuration(duration).
@@ -1268,7 +1268,7 @@ impl PlainDateTime {
 
         let other = to_temporal_datetime(args.get_or_undefined(0), None, context)?;
 
-        let options = get_options_object(args.get_or_undefined(1))?;
+        let options = get_options_object(args.get_or_undefined(1), context.gc_collector())?;
         let settings = get_difference_settings(&options, context)?;
 
         create_temporal_duration(dt.inner.until(&other, settings)?, None, context).map(Into::into)
@@ -1296,7 +1296,7 @@ impl PlainDateTime {
 
         let other = to_temporal_datetime(args.get_or_undefined(0), None, context)?;
 
-        let options = get_options_object(args.get_or_undefined(1))?;
+        let options = get_options_object(args.get_or_undefined(1), context.gc_collector())?;
         let settings = get_difference_settings(&options, context)?;
 
         create_temporal_duration(dt.inner.since(&other, settings)?, None, context).map(Into::into)
@@ -1334,7 +1334,7 @@ impl PlainDateTime {
             // a. Let paramString be roundTo.
             let param_string = param_string.clone();
             // b. Set roundTo to OrdinaryObjectCreate(null).
-            let new_round_to = JsObject::with_null_proto();
+            let new_round_to = JsObject::with_null_proto(context.gc_collector());
             // c. Perform ! CreateDataPropertyOrThrow(roundTo, "smallestUnit", paramString).
             new_round_to.create_data_property_or_throw(
                 js_string!("smallestUnit"),
@@ -1345,7 +1345,7 @@ impl PlainDateTime {
         } else {
             // 5. Else,
             // a. Set roundTo to ? GetOptionsObject(roundTo).
-            get_options_object(round_to_arg)?
+            get_options_object(round_to_arg, context.gc_collector())?
         };
 
         let mut options = RoundingOptions::default();
@@ -1425,7 +1425,7 @@ impl PlainDateTime {
                 JsNativeError::typ().with_message("the this object must be a PlainDateTime object.")
             })?;
 
-        let options = get_options_object(args.get_or_undefined(0))?;
+        let options = get_options_object(args.get_or_undefined(0), context.gc_collector())?;
 
         let show_calendar =
             get_option::<DisplayCalendar>(&options, js_string!("calendarName"), context)?
@@ -1538,7 +1538,7 @@ impl PlainDateTime {
         // 3. Let timeZone be ? ToTemporalTimeZoneIdentifier(temporalTimeZoneLike).
         let timezone = to_temporal_timezone_identifier(args.get_or_undefined(0), context)?;
         // 4. Let resolvedOptions be ? GetOptionsObject(options).
-        let options = get_options_object(args.get_or_undefined(1))?;
+        let options = get_options_object(args.get_or_undefined(1), context.gc_collector())?;
         // 5. Let disambiguation be ? GetTemporalDisambiguationOption(resolvedOptions).
         let disambiguation =
             get_option::<Disambiguation>(&options, js_string!("disambiguation"), context)?
@@ -1647,7 +1647,8 @@ pub(crate) fn create_temporal_datetime(
     // 13. Set object.[[ISOMicrosecond]] to microsecond.
     // 14. Set object.[[ISONanosecond]] to nanosecond.
     // 15. Set object.[[Calendar]] to calendar.
-    let obj = JsObject::from_proto_and_data(prototype, PlainDateTime::new(inner));
+    let obj =
+        JsObject::from_proto_and_data(context.gc_collector(), prototype, PlainDateTime::new(inner));
 
     // 16. Return object.
     Ok(obj)
@@ -1669,7 +1670,7 @@ pub(crate) fn to_temporal_datetime(
         // b. If item has an [[InitializedTemporalZonedDateTime]] internal slot, then
         } else if let Some(zdt) = object.downcast_ref::<ZonedDateTime>() {
             // i. Perform ? GetTemporalOverflowOption(resolvedOptions).
-            let options = get_options_object(&options.unwrap_or_default())?;
+            let options = get_options_object(&options.unwrap_or_default(), context.gc_collector())?;
             let _ = get_option::<Overflow>(&options, js_string!("overflow"), context)?;
             // ii. Let instant be ! CreateTemporalInstant(item.[[Nanoseconds]]).
             // iii. Let timeZoneRec be ? CreateTimeZoneMethodsRecord(item.[[TimeZone]], « get-offset-nanoseconds-for »).
@@ -1678,7 +1679,7 @@ pub(crate) fn to_temporal_datetime(
         // c. If item has an [[InitializedTemporalDate]] internal slot, then
         } else if let Some(date) = object.downcast_ref::<PlainDate>() {
             // i. Perform ? GetTemporalOverflowOption(resolvedOptions).
-            let options = get_options_object(&options.unwrap_or_default())?;
+            let options = get_options_object(&options.unwrap_or_default(), context.gc_collector())?;
             let _ = get_option::<Overflow>(&options, js_string!("overflow"), context)?;
             // ii. Return ? CreateTemporalDateTime(item.[[ISOYear]], item.[[ISOMonth]], item.[[ISODay]], 0, 0, 0, 0, 0, 0, item.[[Calendar]]).
             return Ok(date.inner.to_plain_date_time(None)?);
@@ -1691,7 +1692,8 @@ pub(crate) fn to_temporal_datetime(
         // "nanosecond", "second" », «»)
         // TODO: Move validation to `temporal_rs`.
         let partial_dt = to_partial_datetime(&object, context)?;
-        let resolved_options = get_options_object(&options.unwrap_or_default())?;
+        let resolved_options =
+            get_options_object(&options.unwrap_or_default(), context.gc_collector())?;
         // g. Let result be ? InterpretTemporalDateTimeFields(calendarRec, fields, resolvedOptions).
         let overflow = get_option::<Overflow>(&resolved_options, js_string!("overflow"), context)?;
         return InnerDateTime::from_partial(partial_dt, overflow).map_err(Into::into);
@@ -1713,7 +1715,8 @@ pub(crate) fn to_temporal_datetime(
     // h. Set calendar to CanonicalizeUValue("ca", calendar).
     let date = string.to_std_string_escaped().parse::<InnerDateTime>()?;
     // i. Perform ? GetTemporalOverflowOption(resolvedOptions).
-    let resolved_options = get_options_object(&options.unwrap_or_default())?;
+    let resolved_options =
+        get_options_object(&options.unwrap_or_default(), context.gc_collector())?;
     let _ = get_option::<Overflow>(&resolved_options, js_string!("overflow"), context)?;
     // 5. Return ? CreateTemporalDateTime(result.[[Year]], result.[[Month]], result.[[Day]],
     // result.[[Hour]], result.[[Minute]], result.[[Second]], result.[[Millisecond]],
diff --git a/core/engine/src/builtins/temporal/plain_month_day/mod.rs b/core/engine/src/builtins/temporal/plain_month_day/mod.rs
index dde472d2a2b..b67156053d0 100644
--- a/core/engine/src/builtins/temporal/plain_month_day/mod.rs
+++ b/core/engine/src/builtins/temporal/plain_month_day/mod.rs
@@ -56,20 +56,20 @@ impl BuiltInObject for PlainMonthDay {
 }
 
 impl IntrinsicObject for PlainMonthDay {
-    fn init(realm: &Realm) {
-        let get_day = BuiltInBuilder::callable(realm, Self::get_day)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        let get_day = BuiltInBuilder::callable(realm, Self::get_day, mc)
             .name(js_string!("get day"))
             .build();
 
-        let get_month_code = BuiltInBuilder::callable(realm, Self::get_month_code)
+        let get_month_code = BuiltInBuilder::callable(realm, Self::get_month_code, mc)
             .name(js_string!("get monthCode"))
             .build();
 
-        let get_calendar_id = BuiltInBuilder::callable(realm, Self::get_calendar_id)
+        let get_calendar_id = BuiltInBuilder::callable(realm, Self::get_calendar_id, mc)
             .name(js_string!("get calendarId"))
             .build();
 
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .property(
                 JsSymbol::to_string_tag(),
                 StaticJsStrings::PLAIN_MD_TAG,
@@ -297,7 +297,8 @@ impl PlainMonthDay {
         let fields = to_calendar_fields(&object, month_day.inner.calendar(), context)?;
         // 7. Set fields to CalendarMergeFields(calendar, fields, partialMonthDay).
         // 8. Let resolvedOptions be ? GetOptionsObject(options).
-        let resolved_options = get_options_object(args.get_or_undefined(1))?;
+        let resolved_options =
+            get_options_object(args.get_or_undefined(1), context.gc_collector())?;
         // 9. Let overflow be ? GetTemporalOverflowOption(resolvedOptions).
         let overflow = get_option::<Overflow>(&resolved_options, js_string!("overflow"), context)?;
         // 10. Let isoDate be ? CalendarMonthDayFromFields(calendar, fields, overflow).
@@ -354,7 +355,7 @@ impl PlainMonthDay {
             })?;
 
         // 3. Set options to ? NormalizeOptionsObject(options).
-        let options = get_options_object(args.get_or_undefined(0))?;
+        let options = get_options_object(args.get_or_undefined(0), context.gc_collector())?;
         // 4. Let showCalendar be ? ToShowCalendarOption(options).
         // Get calendarName from the options object
         let show_calendar =
@@ -513,7 +514,8 @@ pub(crate) fn create_temporal_month_day(
     // 6. Set object.[[ISODay]] to isoDay.
     // 7. Set object.[[Calendar]] to calendar.
     // 8. Set object.[[ISOYear]] to referenceISOYear.
-    let obj = JsObject::from_proto_and_data(proto, PlainMonthDay::new(inner));
+    let obj =
+        JsObject::from_proto_and_data(context.gc_collector(), proto, PlainMonthDay::new(inner));
 
     // 9. Return object.
     Ok(obj.into())
@@ -531,7 +533,7 @@ fn to_temporal_month_day(
         // a. If item has an [[InitializedTemporalMonthDay]] internal slot, then
         if let Some(md) = obj.downcast_ref::<PlainMonthDay>() {
             // i. Let resolvedOptions be ? GetOptionsObject(options).
-            let options = get_options_object(options)?;
+            let options = get_options_object(options, context.gc_collector())?;
             // ii. Perform ? GetTemporalOverflowOption(resolvedOptions).
             let _ = get_option::<Overflow>(&options, js_string!("overflow"), context)?;
             // iii. Return ! CreateTemporalMonthDay(item.[[ISODate]], item.[[Calendar]]).
@@ -591,7 +593,7 @@ fn to_temporal_month_day(
             .with_calendar(calendar);
 
         // d. Let resolvedOptions be ? GetOptionsObject(options).
-        let options = get_options_object(options)?;
+        let options = get_options_object(options, context.gc_collector())?;
         // e. Let overflow be ? GetTemporalOverflowOption(resolvedOptions).
         let overflow = get_option::<Overflow>(&options, js_string!("overflow"), context)?;
         // f. Let isoDate be ? CalendarMonthDayFromFields(calendar, fields, overflow).
@@ -612,7 +614,7 @@ fn to_temporal_month_day(
     let parse_record =
         ParsedDate::month_day_from_utf8(md_string.to_std_string_escaped().as_bytes())?;
     // 8. Let resolvedOptions be ? GetOptionsObject(options).
-    let options = get_options_object(options)?;
+    let options = get_options_object(options, context.gc_collector())?;
     // 9. Perform ? GetTemporalOverflowOption(resolvedOptions).
     let _ = get_option::<Overflow>(&options, js_string!("overflow"), context)?;
     // 10. If calendar is "iso8601", then
diff --git a/core/engine/src/builtins/temporal/plain_time/mod.rs b/core/engine/src/builtins/temporal/plain_time/mod.rs
index f9113dd5100..a061bbfa7a1 100644
--- a/core/engine/src/builtins/temporal/plain_time/mod.rs
+++ b/core/engine/src/builtins/temporal/plain_time/mod.rs
@@ -56,32 +56,32 @@ impl BuiltInObject for PlainTime {
 }
 
 impl IntrinsicObject for PlainTime {
-    fn init(realm: &Realm) {
-        let get_hour = BuiltInBuilder::callable(realm, Self::get_hour)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        let get_hour = BuiltInBuilder::callable(realm, Self::get_hour, mc)
             .name(js_string!("get hour"))
             .build();
 
-        let get_minute = BuiltInBuilder::callable(realm, Self::get_minute)
+        let get_minute = BuiltInBuilder::callable(realm, Self::get_minute, mc)
             .name(js_string!("get minute"))
             .build();
 
-        let get_second = BuiltInBuilder::callable(realm, Self::get_second)
+        let get_second = BuiltInBuilder::callable(realm, Self::get_second, mc)
             .name(js_string!("get second"))
             .build();
 
-        let get_millisecond = BuiltInBuilder::callable(realm, Self::get_millisecond)
+        let get_millisecond = BuiltInBuilder::callable(realm, Self::get_millisecond, mc)
             .name(js_string!("get millisecond"))
             .build();
 
-        let get_microsecond = BuiltInBuilder::callable(realm, Self::get_microsecond)
+        let get_microsecond = BuiltInBuilder::callable(realm, Self::get_microsecond, mc)
             .name(js_string!("get microsecond"))
             .build();
 
-        let get_nanosecond = BuiltInBuilder::callable(realm, Self::get_nanosecond)
+        let get_nanosecond = BuiltInBuilder::callable(realm, Self::get_nanosecond, mc)
             .name(js_string!("get nanosecond"))
             .build();
 
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .property(
                 JsSymbol::to_string_tag(),
                 StaticJsStrings::PLAIN_TIME_TAG,
@@ -548,7 +548,7 @@ impl PlainTime {
         let partial = to_js_partial_time_record(&partial_object, context)?;
         // 17. Let resolvedOptions be ? GetOptionsObject(options).
         // 18. Let overflow be ? GetTemporalOverflowOption(resolvedOptions).
-        let options = get_options_object(args.get_or_undefined(1))?;
+        let options = get_options_object(args.get_or_undefined(1), context.gc_collector())?;
         let overflow = get_option::<Overflow>(&options, js_string!("overflow"), context)?;
 
         create_temporal_time(
@@ -582,8 +582,10 @@ impl PlainTime {
 
         let other = to_temporal_time(args.get_or_undefined(0), None, context)?;
 
-        let settings =
-            get_difference_settings(&get_options_object(args.get_or_undefined(1))?, context)?;
+        let settings = get_difference_settings(
+            &get_options_object(args.get_or_undefined(1), context.gc_collector())?,
+            context,
+        )?;
 
         let result = time.inner.until(&other, settings)?;
 
@@ -612,8 +614,10 @@ impl PlainTime {
 
         let other = to_temporal_time(args.get_or_undefined(0), None, context)?;
 
-        let settings =
-            get_difference_settings(&get_options_object(args.get_or_undefined(1))?, context)?;
+        let settings = get_difference_settings(
+            &get_options_object(args.get_or_undefined(1), context.gc_collector())?,
+            context,
+        )?;
 
         let result = time.inner.since(&other, settings)?;
 
@@ -654,7 +658,7 @@ impl PlainTime {
             // a. Let paramString be roundTo.
             let param_string = param_string.clone();
             // b. Set roundTo to OrdinaryObjectCreate(null).
-            let new_round_to = JsObject::with_null_proto();
+            let new_round_to = JsObject::with_null_proto(context.gc_collector());
             // c. Perform ! CreateDataPropertyOrThrow(roundTo, "smallestUnit", paramString).
             new_round_to.create_data_property_or_throw(
                 js_string!("smallestUnit"),
@@ -665,7 +669,7 @@ impl PlainTime {
         } else {
             // 5. Else,
             // a. Set roundTo to ? GetOptionsObject(roundTo).
-            get_options_object(round_to_arg)?
+            get_options_object(round_to_arg, context.gc_collector())?
         };
 
         let mut options = RoundingOptions::default();
@@ -751,7 +755,7 @@ impl PlainTime {
                 JsNativeError::typ().with_message("the this object must be a PlainTime object.")
             })?;
 
-        let options = get_options_object(args.get_or_undefined(0))?;
+        let options = get_options_object(args.get_or_undefined(0), context.gc_collector())?;
 
         let precision = get_digits_option(&options, context)?;
         let rounding_mode =
@@ -868,7 +872,7 @@ pub(crate) fn create_temporal_time(
     // 7. Set object.[[ISOMillisecond]] to millisecond.
     // 8. Set object.[[ISOMicrosecond]] to microsecond.
     // 9. Set object.[[ISONanosecond]] to nanosecond.
-    let obj = JsObject::from_proto_and_data(prototype, PlainTime { inner });
+    let obj = JsObject::from_proto_and_data(context.gc_collector(), prototype, PlainTime { inner });
 
     // 10. Return object.
     Ok(obj)
@@ -889,7 +893,7 @@ pub(crate) fn to_temporal_time(
             // a. If item has an [[InitializedTemporalTime]] internal slot, then
             if let Some(time) = object.downcast_ref::<PlainTime>() {
                 // i. Return item.
-                let options = get_options_object(options)?;
+                let options = get_options_object(options, context.gc_collector())?;
                 let _overflow = get_option::<Overflow>(&options, js_string!("overflow"), context)?;
                 return Ok(time.inner);
             // b. If item has an [[InitializedTemporalZonedDateTime]] internal slot, then
@@ -900,7 +904,7 @@ pub(crate) fn to_temporal_time(
                 // iv. Return ! CreateTemporalTime(plainDateTime.[[ISOHour]], plainDateTime.[[ISOMinute]],
                 // plainDateTime.[[ISOSecond]], plainDateTime.[[ISOMillisecond]], plainDateTime.[[ISOMicrosecond]],
                 // plainDateTime.[[ISONanosecond]]).
-                let options = get_options_object(options)?;
+                let options = get_options_object(options, context.gc_collector())?;
                 let _overflow = get_option::<Overflow>(&options, js_string!("overflow"), context)?;
                 return Ok(zdt.inner.to_plain_time());
             // c. If item has an [[InitializedTemporalDateTime]] internal slot, then
@@ -908,7 +912,7 @@ pub(crate) fn to_temporal_time(
                 // i. Return ! CreateTemporalTime(item.[[ISOHour]], item.[[ISOMinute]],
                 // item.[[ISOSecond]], item.[[ISOMillisecond]], item.[[ISOMicrosecond]],
                 // item.[[ISONanosecond]]).
-                let options = get_options_object(options)?;
+                let options = get_options_object(options, context.gc_collector())?;
                 let _overflow = get_option::<Overflow>(&options, js_string!("overflow"), context)?;
                 return Ok(PlainTimeInner::from(dt.inner.clone()));
             }
@@ -918,7 +922,7 @@ pub(crate) fn to_temporal_time(
             // result.[[Nanosecond]], overflow).
             let partial = to_js_partial_time_record(&object, context)?;
 
-            let options = get_options_object(options)?;
+            let options = get_options_object(options, context.gc_collector())?;
             let overflow = get_option::<Overflow>(&options, js_string!("overflow"), context)?;
 
             PlainTimeInner::from_partial(partial.as_temporal_partial_time(overflow)?, overflow)
@@ -930,7 +934,7 @@ pub(crate) fn to_temporal_time(
             // c. Assert: IsValidTime(result.[[Hour]], result.[[Minute]], result.[[Second]], result.[[Millisecond]], result.[[Microsecond]], result.[[Nanosecond]]) is true.
             let result = str.to_std_string_escaped().parse::<PlainTimeInner>()?;
 
-            let options = get_options_object(options)?;
+            let options = get_options_object(options, context.gc_collector())?;
             let _overflow = get_option::<Overflow>(&options, js_string!("overflow"), context)?;
 
             Ok(result)
diff --git a/core/engine/src/builtins/temporal/plain_year_month/mod.rs b/core/engine/src/builtins/temporal/plain_year_month/mod.rs
index 1c328da5997..7072b4cd3e6 100644
--- a/core/engine/src/builtins/temporal/plain_year_month/mod.rs
+++ b/core/engine/src/builtins/temporal/plain_year_month/mod.rs
@@ -61,48 +61,48 @@ impl BuiltInObject for PlainYearMonth {
 }
 
 impl IntrinsicObject for PlainYearMonth {
-    fn init(realm: &Realm) {
-        let get_calendar_id = BuiltInBuilder::callable(realm, Self::get_calendar_id)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        let get_calendar_id = BuiltInBuilder::callable(realm, Self::get_calendar_id, mc)
             .name(js_string!("get calendarId"))
             .build();
 
-        let get_era_year = BuiltInBuilder::callable(realm, Self::get_era_year)
+        let get_era_year = BuiltInBuilder::callable(realm, Self::get_era_year, mc)
             .name(js_string!("get eraYear"))
             .build();
 
-        let get_era = BuiltInBuilder::callable(realm, Self::get_era)
+        let get_era = BuiltInBuilder::callable(realm, Self::get_era, mc)
             .name(js_string!("get era"))
             .build();
 
-        let get_year = BuiltInBuilder::callable(realm, Self::get_year)
+        let get_year = BuiltInBuilder::callable(realm, Self::get_year, mc)
             .name(js_string!("get year"))
             .build();
 
-        let get_month = BuiltInBuilder::callable(realm, Self::get_month)
+        let get_month = BuiltInBuilder::callable(realm, Self::get_month, mc)
             .name(js_string!("get month"))
             .build();
 
-        let get_month_code = BuiltInBuilder::callable(realm, Self::get_month_code)
+        let get_month_code = BuiltInBuilder::callable(realm, Self::get_month_code, mc)
             .name(js_string!("get monthCode"))
             .build();
 
-        let get_days_in_month = BuiltInBuilder::callable(realm, Self::get_days_in_month)
+        let get_days_in_month = BuiltInBuilder::callable(realm, Self::get_days_in_month, mc)
             .name(js_string!("get daysInMonth"))
             .build();
 
-        let get_days_in_year = BuiltInBuilder::callable(realm, Self::get_days_in_year)
+        let get_days_in_year = BuiltInBuilder::callable(realm, Self::get_days_in_year, mc)
             .name(js_string!("get daysInYear"))
             .build();
 
-        let get_months_in_year = BuiltInBuilder::callable(realm, Self::get_months_in_year)
+        let get_months_in_year = BuiltInBuilder::callable(realm, Self::get_months_in_year, mc)
             .name(js_string!("get monthsInYear"))
             .build();
 
-        let get_in_leap_year = BuiltInBuilder::callable(realm, Self::get_in_leap_year)
+        let get_in_leap_year = BuiltInBuilder::callable(realm, Self::get_in_leap_year, mc)
             .name(js_string!("get inLeapYear"))
             .build();
 
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .property(
                 JsSymbol::to_string_tag(),
                 StaticJsStrings::PLAIN_YM_TAG,
@@ -571,7 +571,8 @@ impl PlainYearMonth {
                 .into());
         }
         // 8. Let resolvedOptions be ? GetOptionsObject(options).
-        let resolved_options = get_options_object(args.get_or_undefined(1))?;
+        let resolved_options =
+            get_options_object(args.get_or_undefined(1), context.gc_collector())?;
         // 9. Let overflow be ? GetTemporalOverflowOption(resolvedOptions).
         let overflow = get_option::<Overflow>(&resolved_options, js_string!("overflow"), context)?
             .unwrap_or_default();
@@ -594,7 +595,7 @@ impl PlainYearMonth {
     /// [temporal_rs-docs]: https://docs.rs/temporal_rs/latest/temporal_rs/struct.PlainYearMonth.html#method.add
     fn add(this: &JsValue, args: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
         let duration_like = args.get_or_undefined(0);
-        let options = get_options_object(args.get_or_undefined(1))?;
+        let options = get_options_object(args.get_or_undefined(1), context.gc_collector())?;
 
         add_or_subtract_duration(true, this, duration_like, &options, context)
     }
@@ -612,7 +613,7 @@ impl PlainYearMonth {
     /// [temporal_rs-docs]: https://docs.rs/temporal_rs/latest/temporal_rs/struct.PlainYearMonth.html#method.subtract
     fn subtract(this: &JsValue, args: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
         let duration_like = args.get_or_undefined(0);
-        let options = get_options_object(args.get_or_undefined(1))?;
+        let options = get_options_object(args.get_or_undefined(1), context.gc_collector())?;
 
         add_or_subtract_duration(false, this, duration_like, &options, context)
     }
@@ -645,7 +646,8 @@ impl PlainYearMonth {
                 .into());
         }
 
-        let resolved_options = get_options_object(args.get_or_undefined(1))?;
+        let resolved_options =
+            get_options_object(args.get_or_undefined(1), context.gc_collector())?;
         // TODO: Disallowed units must be rejected in `temporal_rs`.
         let settings = get_difference_settings(&resolved_options, context)?;
         let result = year_month.inner.until(&other, settings)?;
@@ -680,7 +682,8 @@ impl PlainYearMonth {
                 .into());
         }
 
-        let resolved_options = get_options_object(args.get_or_undefined(1))?;
+        let resolved_options =
+            get_options_object(args.get_or_undefined(1), context.gc_collector())?;
         // TODO: Disallowed units must be rejected in `temporal_rs`.
         let settings = get_difference_settings(&resolved_options, context)?;
         let result = year_month.inner.since(&other, settings)?;
@@ -735,7 +738,7 @@ impl PlainYearMonth {
             })?;
 
         // 3. Set options to ? NormalizeOptionsObject(options).
-        let options = get_options_object(args.get_or_undefined(0))?;
+        let options = get_options_object(args.get_or_undefined(0), context.gc_collector())?;
         // 4. Let showCalendar be ? ToShowCalendarOption(options).
         // Get calendarName from the options object
         let show_calendar =
@@ -875,7 +878,7 @@ fn to_temporal_year_month(
         // a. If item has an [[InitializedTemporalYearMonth]] internal slot, then
         if let Some(ym) = obj.downcast_ref::<PlainYearMonth>() {
             // i. Let resolvedOptions be ? GetOptionsObject(options).
-            let resolved_options = get_options_object(&options)?;
+            let resolved_options = get_options_object(&options, context.gc_collector())?;
             // ii. Perform ? GetTemporalOverflowOption(resolvedOptions).
             let _overflow =
                 get_option::<Overflow>(&resolved_options, js_string!("overflow"), context)?
@@ -887,7 +890,7 @@ fn to_temporal_year_month(
         // c. Let fields be ? PrepareCalendarFields(calendar, item, « year, month, month-code », «», «»).
         let partial = to_partial_year_month(&obj, context)?;
         // d. Let resolvedOptions be ? GetOptionsObject(options).
-        let resolved_options = get_options_object(&options)?;
+        let resolved_options = get_options_object(&options, context.gc_collector())?;
         // e. Let overflow be ? GetTemporalOverflowOption(resolvedOptions).
         let overflow = get_option::<Overflow>(&resolved_options, js_string!("overflow"), context)?;
         // f. Let isoDate be ? CalendarYearMonthFromFields(calendar, fields, overflow).
@@ -908,7 +911,7 @@ fn to_temporal_year_month(
     // 6. If calendar is empty, set calendar to "iso8601".
     // 7. Set calendar to ? CanonicalizeCalendar(calendar).
     // 8. Let resolvedOptions be ? GetOptionsObject(options).
-    let resolved_options = get_options_object(&options)?;
+    let resolved_options = get_options_object(&options, context.gc_collector())?;
     // 9. Perform ? GetTemporalOverflowOption(resolvedOptions).
     let _overflow = get_option::<Overflow>(&resolved_options, js_string!("overflow"), context)?
         .unwrap_or(Overflow::Constrain);
@@ -956,7 +959,7 @@ pub(crate) fn create_temporal_year_month(
     // 7. Set object.[[Calendar]] to calendar.
     // 8. Set object.[[ISODay]] to referenceISODay.
 
-    let obj = JsObject::from_proto_and_data(proto, PlainYearMonth::new(ym));
+    let obj = JsObject::from_proto_and_data(context.gc_collector(), proto, PlainYearMonth::new(ym));
 
     // 9. Return object.
     Ok(obj.into())
diff --git a/core/engine/src/builtins/temporal/zoneddatetime/mod.rs b/core/engine/src/builtins/temporal/zoneddatetime/mod.rs
index 7f186c87878..f3f40a632ef 100644
--- a/core/engine/src/builtins/temporal/zoneddatetime/mod.rs
+++ b/core/engine/src/builtins/temporal/zoneddatetime/mod.rs
@@ -71,120 +71,122 @@ impl BuiltInObject for ZonedDateTime {
 }
 
 impl IntrinsicObject for ZonedDateTime {
-    fn init(realm: &Realm) {
-        let get_calendar_id = BuiltInBuilder::callable(realm, Self::get_calendar_id)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        let get_calendar_id = BuiltInBuilder::callable(realm, Self::get_calendar_id, mc)
             .name(js_string!("get calendarId"))
             .build();
 
-        let get_timezone_id = BuiltInBuilder::callable(realm, Self::get_timezone_id)
+        let get_timezone_id = BuiltInBuilder::callable(realm, Self::get_timezone_id, mc)
             .name(js_string!("get timeZoneId"))
             .build();
 
-        let get_era = BuiltInBuilder::callable(realm, Self::get_era)
+        let get_era = BuiltInBuilder::callable(realm, Self::get_era, mc)
             .name(js_string!("get era"))
             .build();
 
-        let get_era_year = BuiltInBuilder::callable(realm, Self::get_era_year)
+        let get_era_year = BuiltInBuilder::callable(realm, Self::get_era_year, mc)
             .name(js_string!("get eraYear"))
             .build();
 
-        let get_year = BuiltInBuilder::callable(realm, Self::get_year)
+        let get_year = BuiltInBuilder::callable(realm, Self::get_year, mc)
             .name(js_string!("get year"))
             .build();
 
-        let get_month = BuiltInBuilder::callable(realm, Self::get_month)
+        let get_month = BuiltInBuilder::callable(realm, Self::get_month, mc)
             .name(js_string!("get month"))
             .build();
 
-        let get_month_code = BuiltInBuilder::callable(realm, Self::get_month_code)
+        let get_month_code = BuiltInBuilder::callable(realm, Self::get_month_code, mc)
             .name(js_string!("get monthCode"))
             .build();
 
-        let get_day = BuiltInBuilder::callable(realm, Self::get_day)
+        let get_day = BuiltInBuilder::callable(realm, Self::get_day, mc)
             .name(js_string!("get day"))
             .build();
 
-        let get_hour = BuiltInBuilder::callable(realm, Self::get_hour)
+        let get_hour = BuiltInBuilder::callable(realm, Self::get_hour, mc)
             .name(js_string!("get hour"))
             .build();
 
-        let get_minute = BuiltInBuilder::callable(realm, Self::get_minute)
+        let get_minute = BuiltInBuilder::callable(realm, Self::get_minute, mc)
             .name(js_string!("get minute"))
             .build();
 
-        let get_second = BuiltInBuilder::callable(realm, Self::get_second)
+        let get_second = BuiltInBuilder::callable(realm, Self::get_second, mc)
             .name(js_string!("get second"))
             .build();
 
-        let get_millisecond = BuiltInBuilder::callable(realm, Self::get_millisecond)
+        let get_millisecond = BuiltInBuilder::callable(realm, Self::get_millisecond, mc)
             .name(js_string!("get millisecond"))
             .build();
 
-        let get_microsecond = BuiltInBuilder::callable(realm, Self::get_microsecond)
+        let get_microsecond = BuiltInBuilder::callable(realm, Self::get_microsecond, mc)
             .name(js_string!("get microsecond"))
             .build();
 
-        let get_nanosecond = BuiltInBuilder::callable(realm, Self::get_nanosecond)
+        let get_nanosecond = BuiltInBuilder::callable(realm, Self::get_nanosecond, mc)
             .name(js_string!("get nanosecond"))
             .build();
 
-        let get_epoch_milliseconds = BuiltInBuilder::callable(realm, Self::get_epoch_milliseconds)
-            .name(js_string!("get epochMilliseconds"))
-            .build();
+        let get_epoch_milliseconds =
+            BuiltInBuilder::callable(realm, Self::get_epoch_milliseconds, mc)
+                .name(js_string!("get epochMilliseconds"))
+                .build();
 
-        let get_epoch_nanoseconds = BuiltInBuilder::callable(realm, Self::get_epoch_nanoseconds)
-            .name(js_string!("get epochNanoseconds"))
-            .build();
+        let get_epoch_nanoseconds =
+            BuiltInBuilder::callable(realm, Self::get_epoch_nanoseconds, mc)
+                .name(js_string!("get epochNanoseconds"))
+                .build();
 
-        let get_day_of_week = BuiltInBuilder::callable(realm, Self::get_day_of_week)
+        let get_day_of_week = BuiltInBuilder::callable(realm, Self::get_day_of_week, mc)
             .name(js_string!("get dayOfWeek"))
             .build();
 
-        let get_day_of_year = BuiltInBuilder::callable(realm, Self::get_day_of_year)
+        let get_day_of_year = BuiltInBuilder::callable(realm, Self::get_day_of_year, mc)
             .name(js_string!("get dayOfYear"))
             .build();
 
-        let get_week_of_year = BuiltInBuilder::callable(realm, Self::get_week_of_year)
+        let get_week_of_year = BuiltInBuilder::callable(realm, Self::get_week_of_year, mc)
             .name(js_string!("get weekOfYear"))
             .build();
 
-        let get_hours_in_day = BuiltInBuilder::callable(realm, Self::get_hours_in_day)
+        let get_hours_in_day = BuiltInBuilder::callable(realm, Self::get_hours_in_day, mc)
             .name(js_string!("get daysInWeek"))
             .build();
 
-        let get_year_of_week = BuiltInBuilder::callable(realm, Self::get_year_of_week)
+        let get_year_of_week = BuiltInBuilder::callable(realm, Self::get_year_of_week, mc)
             .name(js_string!("get yearOfWeek"))
             .build();
 
-        let get_days_in_week = BuiltInBuilder::callable(realm, Self::get_days_in_week)
+        let get_days_in_week = BuiltInBuilder::callable(realm, Self::get_days_in_week, mc)
             .name(js_string!("get daysInWeek"))
             .build();
 
-        let get_days_in_month = BuiltInBuilder::callable(realm, Self::get_days_in_month)
+        let get_days_in_month = BuiltInBuilder::callable(realm, Self::get_days_in_month, mc)
             .name(js_string!("get daysInMonth"))
             .build();
 
-        let get_days_in_year = BuiltInBuilder::callable(realm, Self::get_days_in_year)
+        let get_days_in_year = BuiltInBuilder::callable(realm, Self::get_days_in_year, mc)
             .name(js_string!("get daysInYear"))
             .build();
 
-        let get_months_in_year = BuiltInBuilder::callable(realm, Self::get_months_in_year)
+        let get_months_in_year = BuiltInBuilder::callable(realm, Self::get_months_in_year, mc)
             .name(js_string!("get monthsInYear"))
             .build();
 
-        let get_in_leap_year = BuiltInBuilder::callable(realm, Self::get_in_leap_year)
+        let get_in_leap_year = BuiltInBuilder::callable(realm, Self::get_in_leap_year, mc)
             .name(js_string!("get inLeapYear"))
             .build();
 
-        let get_offset_nanos = BuiltInBuilder::callable(realm, Self::get_offset_nanoseconds)
+        let get_offset_nanos = BuiltInBuilder::callable(realm, Self::get_offset_nanoseconds, mc)
             .name(js_string!("get offsetNanoseconds"))
             .build();
 
-        let get_offset = BuiltInBuilder::callable(realm, Self::get_offset)
+        let get_offset = BuiltInBuilder::callable(realm, Self::get_offset, mc)
             .name(js_string!("get offset"))
             .build();
 
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .property(
                 JsSymbol::to_string_tag(),
                 StaticJsStrings::ZONED_DT_TAG,
@@ -1214,7 +1216,8 @@ impl ZonedDateTime {
         )?;
 
         // 19. Let resolvedOptions be ? GetOptionsObject(options).
-        let resolved_options = get_options_object(args.get_or_undefined(1))?;
+        let resolved_options =
+            get_options_object(args.get_or_undefined(1), context.gc_collector())?;
         // 20. Let disambiguation be ? GetTemporalDisambiguationOption(resolvedOptions).
         let disambiguation =
             get_option::<Disambiguation>(&resolved_options, js_string!("disambiguation"), context)?;
@@ -1345,7 +1348,7 @@ impl ZonedDateTime {
 
         let duration = to_temporal_duration(args.get_or_undefined(0), context)?;
 
-        let options = get_options_object(args.get_or_undefined(1))?;
+        let options = get_options_object(args.get_or_undefined(1), context.gc_collector())?;
         let overflow = get_option::<Overflow>(&options, js_string!("overflow"), context)?;
 
         let result =
@@ -1376,7 +1379,7 @@ impl ZonedDateTime {
 
         let duration = to_temporal_duration(args.get_or_undefined(0), context)?;
 
-        let options = get_options_object(args.get_or_undefined(1))?;
+        let options = get_options_object(args.get_or_undefined(1), context.gc_collector())?;
         let overflow = get_option::<Overflow>(&options, js_string!("overflow"), context)?;
 
         let result =
@@ -1407,7 +1410,7 @@ impl ZonedDateTime {
 
         let other = to_temporal_zoneddatetime(args.get_or_undefined(0), None, context)?;
 
-        let options = get_options_object(args.get_or_undefined(1))?;
+        let options = get_options_object(args.get_or_undefined(1), context.gc_collector())?;
         let settings = get_difference_settings(&options, context)?;
 
         let result =
@@ -1438,7 +1441,7 @@ impl ZonedDateTime {
 
         let other = to_temporal_zoneddatetime(args.get_or_undefined(0), None, context)?;
 
-        let options = get_options_object(args.get_or_undefined(1))?;
+        let options = get_options_object(args.get_or_undefined(1), context.gc_collector())?;
         let settings = get_difference_settings(&options, context)?;
 
         let result =
@@ -1482,7 +1485,7 @@ impl ZonedDateTime {
             // a. Let paramString be roundTo.
             let param_string = param_string.clone();
             // b. Set roundTo to OrdinaryObjectCreate(null).
-            let new_round_to = JsObject::with_null_proto();
+            let new_round_to = JsObject::with_null_proto(context.gc_collector());
             // c. Perform ! CreateDataPropertyOrThrow(roundTo, "smallestUnit", paramString).
             new_round_to.create_data_property_or_throw(
                 js_string!("smallestUnit"),
@@ -1493,7 +1496,7 @@ impl ZonedDateTime {
         } else {
             // 5. Else,
             // a. Set roundTo to ? GetOptionsObject(roundTo).
-            get_options_object(round_to_arg)?
+            get_options_object(round_to_arg, context.gc_collector())?
         };
 
         // 6. NOTE: The following steps read options and perform independent validation
@@ -1571,7 +1574,7 @@ impl ZonedDateTime {
                 JsNativeError::typ().with_message("the this object must be a ZonedDateTime object.")
             })?;
 
-        let options = get_options_object(args.get_or_undefined(0))?;
+        let options = get_options_object(args.get_or_undefined(0), context.gc_collector())?;
 
         let show_calendar =
             get_option::<DisplayCalendar>(&options, js_string!("calendarName"), context)?
@@ -1741,7 +1744,7 @@ impl ZonedDateTime {
         let options_obj = if let Some(param_str) = direction_param.as_string() {
             // a. Let paramString be directionParam.
             // b. Set directionParam to OrdinaryObjectCreate(null).
-            let obj = JsObject::with_null_proto();
+            let obj = JsObject::with_null_proto(context.gc_collector());
             // c. Perform ! CreateDataPropertyOrThrow(directionParam, "direction", paramString).
             obj.create_data_property_or_throw(
                 js_string!("direction"),
@@ -1752,7 +1755,7 @@ impl ZonedDateTime {
         // 6. Else,
         } else {
             // a. Set directionParam to ? GetOptionsObject(directionParam).
-            get_options_object(direction_param)?
+            get_options_object(direction_param, context.gc_collector())?
         };
 
         // TODO: step 7
@@ -1902,7 +1905,8 @@ pub(crate) fn create_temporal_zoneddatetime(
     // 4. Set object.[[EpochNanoseconds]] to epochNanoseconds.
     // 5. Set object.[[TimeZone]] to timeZone.
     // 6. Set object.[[Calendar]] to calendar.
-    let obj = JsObject::from_proto_and_data(prototype, ZonedDateTime::new(inner));
+    let obj =
+        JsObject::from_proto_and_data(context.gc_collector(), prototype, ZonedDateTime::new(inner));
 
     // 7. Return object.
     Ok(obj)
@@ -1927,7 +1931,10 @@ pub(crate) fn to_temporal_zoneddatetime(
                 // (GetTemporalDisambiguationOption reads "disambiguation", GetTemporalOffsetOption
                 // reads "offset", and GetTemporalOverflowOption reads "overflow").
                 // ii. Let resolvedOptions be ? GetOptionsObject(options).
-                let options = get_options_object(options.unwrap_or(&JsValue::undefined()))?;
+                let options = get_options_object(
+                    options.unwrap_or(&JsValue::undefined()),
+                    context.gc_collector(),
+                )?;
                 // iii. Perform ? GetTemporalDisambiguationOption(resolvedOptions).
                 let _disambiguation =
                     get_option::<Disambiguation>(&options, js_string!("disambiguation"), context)?
@@ -1946,7 +1953,10 @@ pub(crate) fn to_temporal_zoneddatetime(
             // f. If offsetString is unset, the
             // i. Set offsetBehaviour to wall.
             // g. Let resolvedOptions be ? GetOptionsObject(options).
-            let options = get_options_object(options.unwrap_or(&JsValue::undefined()))?;
+            let options = get_options_object(
+                options.unwrap_or(&JsValue::undefined()),
+                context.gc_collector(),
+            )?;
             // h. Let disambiguation be ? GetTemporalDisambiguationOption(resolvedOptions).
             let disambiguation =
                 get_option::<Disambiguation>(&options, js_string!("disambiguation"), context)?;
@@ -1985,7 +1995,10 @@ pub(crate) fn to_temporal_zoneddatetime(
             // k. Set calendar to ? CanonicalizeCalendar(calendar).
             // l. Set matchBehaviour to match-minutes.
             // m. Let resolvedOptions be ? GetOptionsObject(options).
-            let options = get_options_object(options.unwrap_or(&JsValue::undefined()))?;
+            let options = get_options_object(
+                options.unwrap_or(&JsValue::undefined()),
+                context.gc_collector(),
+            )?;
             // n. Let disambiguation be ? GetTemporalDisambiguationOption(resolvedOptions).
             let disambiguation =
                 get_option::<Disambiguation>(&options, js_string!("disambiguation"), context)?
diff --git a/core/engine/src/builtins/typed_array/builtin.rs b/core/engine/src/builtins/typed_array/builtin.rs
index 5dae075cb19..c22d21a9c20 100644
--- a/core/engine/src/builtins/typed_array/builtin.rs
+++ b/core/engine/src/builtins/typed_array/builtin.rs
@@ -35,37 +35,37 @@ use crate::{builtins::array_buffer::utils::memmove_naive, value::JsVariant};
 pub(crate) struct BuiltinTypedArray;
 
 impl IntrinsicObject for BuiltinTypedArray {
-    fn init(realm: &Realm) {
-        let get_species = BuiltInBuilder::callable(realm, Self::get_species)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        let get_species = BuiltInBuilder::callable(realm, Self::get_species, mc)
             .name(js_string!("get [Symbol.species]"))
             .build();
 
-        let get_buffer = BuiltInBuilder::callable(realm, Self::buffer)
+        let get_buffer = BuiltInBuilder::callable(realm, Self::buffer, mc)
             .name(js_string!("get buffer"))
             .build();
 
-        let get_byte_length = BuiltInBuilder::callable(realm, Self::byte_length)
+        let get_byte_length = BuiltInBuilder::callable(realm, Self::byte_length, mc)
             .name(js_string!("get byteLength"))
             .build();
 
-        let get_byte_offset = BuiltInBuilder::callable(realm, Self::byte_offset)
+        let get_byte_offset = BuiltInBuilder::callable(realm, Self::byte_offset, mc)
             .name(js_string!("get byteOffset"))
             .build();
 
-        let get_length = BuiltInBuilder::callable(realm, Self::length)
+        let get_length = BuiltInBuilder::callable(realm, Self::length, mc)
             .name(js_string!("get length"))
             .build();
 
-        let get_to_string_tag = BuiltInBuilder::callable(realm, Self::to_string_tag)
+        let get_to_string_tag = BuiltInBuilder::callable(realm, Self::to_string_tag, mc)
             .name(js_string!("get [Symbol.toStringTag]"))
             .build();
 
-        let values_function = BuiltInBuilder::callable(realm, Self::values)
+        let values_function = BuiltInBuilder::callable(realm, Self::values, mc)
             .name(js_string!("values"))
             .length(0)
             .build();
 
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .static_accessor(
                 JsSymbol::species(),
                 Some(get_species),
@@ -2815,8 +2815,13 @@ impl BuiltinTypedArray {
         let len = values.len() as u64;
         // 2. Perform ? AllocateTypedArrayBuffer(O, len).
         let buf = Self::allocate_buffer::<T>(len, context)?;
-        let obj = JsObject::from_proto_and_data_with_shared_shape(context.root_shape(), proto, buf)
-            .upcast();
+        let obj = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
+            context.root_shape(),
+            proto,
+            buf,
+        )
+        .upcast();
 
         // 3. Let k be 0.
         // 4. Repeat, while k < len,
@@ -2865,9 +2870,13 @@ impl BuiltinTypedArray {
         let indexed = Self::allocate_buffer::<T>(length, context)?;
 
         // 2. Let obj be ! IntegerIndexedObjectCreate(proto).
-        let obj =
-            JsObject::from_proto_and_data_with_shared_shape(context.root_shape(), proto, indexed)
-                .upcast();
+        let obj = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
+            context.root_shape(),
+            proto,
+            indexed,
+        )
+        .upcast();
 
         // 9. Return obj.
         Ok(obj)
@@ -3008,6 +3017,7 @@ impl BuiltinTypedArray {
         // 15. Set O.[[ByteOffset]] to 0.
         // 16. Set O.[[ArrayLength]] to elementLength.
         let obj = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             proto,
             TypedArray::new(
@@ -3128,6 +3138,7 @@ impl BuiltinTypedArray {
         // 11. Set O.[[ByteOffset]] to offset.
         // 12. Return unused.
         Ok(JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             proto,
             TypedArray::new(buffer, T::ERASED, offset, byte_length, array_length),
@@ -3151,8 +3162,13 @@ impl BuiltinTypedArray {
 
         // 2. Perform ? AllocateTypedArrayBuffer(O, len).
         let buf = Self::allocate_buffer::<T>(len, context)?;
-        let obj = JsObject::from_proto_and_data_with_shared_shape(context.root_shape(), proto, buf)
-            .upcast();
+        let obj = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
+            context.root_shape(),
+            proto,
+            buf,
+        )
+        .upcast();
 
         // 3. Let k be 0.
         // 4. Repeat, while k < len,
diff --git a/core/engine/src/builtins/typed_array/mod.rs b/core/engine/src/builtins/typed_array/mod.rs
index d79c8d188c5..2d6546df197 100644
--- a/core/engine/src/builtins/typed_array/mod.rs
+++ b/core/engine/src/builtins/typed_array/mod.rs
@@ -47,12 +47,12 @@ impl<T: TypedArrayMarker> IntrinsicObject for T {
         Self::STANDARD_CONSTRUCTOR(intrinsics.constructors()).constructor()
     }
 
-    fn init(realm: &Realm) {
-        let get_species = BuiltInBuilder::callable(realm, BuiltinTypedArray::get_species)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        let get_species = BuiltInBuilder::callable(realm, BuiltinTypedArray::get_species, mc)
             .name(js_string!("get [Symbol.species]"))
             .build();
 
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .prototype(
                 realm
                     .intrinsics()
diff --git a/core/engine/src/builtins/uri/mod.rs b/core/engine/src/builtins/uri/mod.rs
index 6a5baadb554..58d8ff73be2 100644
--- a/core/engine/src/builtins/uri/mod.rs
+++ b/core/engine/src/builtins/uri/mod.rs
@@ -87,8 +87,8 @@ impl UriFunctions {
 pub(crate) struct DecodeUri;
 
 impl IntrinsicObject for DecodeUri {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::callable_with_intrinsic::<Self>(realm, decode_uri)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::callable_with_intrinsic::<Self>(realm, decode_uri, mc)
             .name(Self::NAME)
             .length(1)
             .build();
@@ -105,8 +105,8 @@ impl BuiltInObject for DecodeUri {
 pub(crate) struct DecodeUriComponent;
 
 impl IntrinsicObject for DecodeUriComponent {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::callable_with_intrinsic::<Self>(realm, decode_uri_component)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::callable_with_intrinsic::<Self>(realm, decode_uri_component, mc)
             .name(Self::NAME)
             .length(1)
             .build();
@@ -127,8 +127,8 @@ impl BuiltInObject for DecodeUriComponent {
 pub(crate) struct EncodeUri;
 
 impl IntrinsicObject for EncodeUri {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::callable_with_intrinsic::<Self>(realm, encode_uri)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::callable_with_intrinsic::<Self>(realm, encode_uri, mc)
             .name(Self::NAME)
             .length(1)
             .build();
@@ -144,8 +144,8 @@ impl BuiltInObject for EncodeUri {
 pub(crate) struct EncodeUriComponent;
 
 impl IntrinsicObject for EncodeUriComponent {
-    fn init(realm: &Realm) {
-        BuiltInBuilder::callable_with_intrinsic::<Self>(realm, encode_uri_component)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::callable_with_intrinsic::<Self>(realm, encode_uri_component, mc)
             .name(Self::NAME)
             .length(1)
             .build();
diff --git a/core/engine/src/builtins/weak/weak_ref.rs b/core/engine/src/builtins/weak/weak_ref.rs
index 83b92e27a82..308f273e8db 100644
--- a/core/engine/src/builtins/weak/weak_ref.rs
+++ b/core/engine/src/builtins/weak/weak_ref.rs
@@ -30,8 +30,8 @@ impl IntrinsicObject for WeakRef {
         Self::STANDARD_CONSTRUCTOR(intrinsics.constructors()).constructor()
     }
 
-    fn init(realm: &Realm) {
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .property(
                 JsSymbol::to_string_tag(),
                 js_string!("WeakRef"),
@@ -85,6 +85,7 @@ impl BuiltInConstructor for WeakRef {
         let prototype =
             get_prototype_from_constructor(new_target, StandardConstructors::weak_ref, context)?;
         let weak_ref = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             prototype,
             WeakGc::new(context.gc_collector(), target.inner()),
diff --git a/core/engine/src/builtins/weak_map/mod.rs b/core/engine/src/builtins/weak_map/mod.rs
index 91e88290846..b286a6359d2 100644
--- a/core/engine/src/builtins/weak_map/mod.rs
+++ b/core/engine/src/builtins/weak_map/mod.rs
@@ -36,8 +36,8 @@ impl IntrinsicObject for WeakMap {
         Self::STANDARD_CONSTRUCTOR(intrinsics.constructors()).constructor()
     }
 
-    fn init(realm: &Realm) {
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .property(
                 JsSymbol::to_string_tag(),
                 Self::NAME,
@@ -95,6 +95,7 @@ impl BuiltInConstructor for WeakMap {
         let prototype =
             get_prototype_from_constructor(new_target, StandardConstructors::weak_map, context)?;
         let map = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             prototype,
             NativeWeakMap::new(context.gc_collector()),
diff --git a/core/engine/src/builtins/weak_set/mod.rs b/core/engine/src/builtins/weak_set/mod.rs
index 73ca5456716..79855e5886f 100644
--- a/core/engine/src/builtins/weak_set/mod.rs
+++ b/core/engine/src/builtins/weak_set/mod.rs
@@ -32,8 +32,8 @@ impl IntrinsicObject for WeakSet {
         Self::STANDARD_CONSTRUCTOR(intrinsics.constructors()).constructor()
     }
 
-    fn init(realm: &Realm) {
-        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+    fn init(realm: &Realm, mc: &boa_gc::MutationContext<'static, '_>) {
+        BuiltInBuilder::from_standard_constructor::<Self>(realm, mc)
             .property(
                 JsSymbol::to_string_tag(),
                 Self::NAME,
@@ -84,6 +84,7 @@ impl BuiltInConstructor for WeakSet {
         let prototype =
             get_prototype_from_constructor(new_target, StandardConstructors::weak_set, context)?;
         let weak_set = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             prototype,
             NativeWeakSet::new(context.gc_collector()),
diff --git a/core/engine/src/class.rs b/core/engine/src/class.rs
index 91ac60edb3e..ffa3b875531 100644
--- a/core/engine/src/class.rs
+++ b/core/engine/src/class.rs
@@ -196,8 +196,12 @@ pub trait Class: NativeObject + Sized {
 
         let data = Self::data_constructor(new_target, args, context)?;
 
-        let object =
-            JsObject::from_proto_and_data_with_shared_shape(context.root_shape(), prototype, data);
+        let object = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
+            context.root_shape(),
+            prototype,
+            data,
+        );
 
         Self::object_constructor(&object, args, context)?;
 
@@ -228,8 +232,12 @@ pub trait Class: NativeObject + Sized {
             })?
             .prototype();
 
-        let object =
-            JsObject::from_proto_and_data_with_shared_shape(context.root_shape(), prototype, data);
+        let object = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
+            context.root_shape(),
+            prototype,
+            data,
+        );
 
         Self::object_constructor(&object, &[], context)?;
 
diff --git a/core/engine/src/context/hooks.rs b/core/engine/src/context/hooks.rs
index c1f2906563c..2560c21eb71 100644
--- a/core/engine/src/context/hooks.rs
+++ b/core/engine/src/context/hooks.rs
@@ -169,8 +169,12 @@ pub trait HostHooks {
     /// Equivalent to the step 7 of [`InitializeHostDefinedRealm ( )`][ihdr].
     ///
     /// [ihdr]: https://tc39.es/ecma262/#sec-initializehostdefinedrealm
-    fn create_global_object(&self, intrinsics: &Intrinsics) -> JsObject {
-        JsObject::with_object_proto(intrinsics)
+    fn create_global_object(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        intrinsics: &Intrinsics,
+    ) -> JsObject {
+        JsObject::with_object_proto(mc, intrinsics)
     }
 
     /// Creates the global `this` of a new [`Context`] from the initial intrinsics.
diff --git a/core/engine/src/context/intrinsics.rs b/core/engine/src/context/intrinsics.rs
index edd57db8cdf..7a182e34317 100644
--- a/core/engine/src/context/intrinsics.rs
+++ b/core/engine/src/context/intrinsics.rs
@@ -79,18 +79,12 @@ pub struct StandardConstructor {
     prototype: JsObject,
 }
 
-impl Default for StandardConstructor {
-    fn default() -> Self {
-        Self::uninit(&unsafe { boa_gc::MutationContext::global() })
-    }
-}
-
 impl StandardConstructor {
     /// Creates a new uninitialized `StandardConstructor` using the given context.
     pub(crate) fn uninit(mc: &boa_gc::MutationContext<'static, '_>) -> Self {
         Self {
             constructor: JsFunction::empty_intrinsic_function_in(mc, true),
-            prototype: JsObject::with_null_proto_in(mc),
+            prototype: JsObject::with_null_proto(mc),
         }
     }
     /// Creates a new `StandardConstructor` from the constructor and the prototype.
@@ -102,7 +96,7 @@ impl StandardConstructor {
     }
 
     /// Build a constructor with a defined prototype, using the given context.
-    fn with_prototype_in(mc: &boa_gc::MutationContext<'static, '_>, prototype: JsObject) -> Self {
+    fn with_prototype(mc: &boa_gc::MutationContext<'static, '_>, prototype: JsObject) -> Self {
         Self {
             constructor: JsFunction::empty_intrinsic_function_in(mc, true),
             prototype,
@@ -110,9 +104,6 @@ impl StandardConstructor {
     }
 
     /// Build a constructor with a defined prototype.
-    fn with_prototype(prototype: JsObject) -> Self {
-        Self::with_prototype_in(&unsafe { boa_gc::MutationContext::global() }, prototype)
-    }
 
     /// Return the prototype of the constructor object.
     ///
@@ -221,9 +212,9 @@ pub struct StandardConstructors {
 impl StandardConstructors {
     pub(crate) fn uninit(mc: &boa_gc::MutationContext<'static, '_>) -> Self {
         Self {
-            object: StandardConstructor::with_prototype_in(
+            object: StandardConstructor::with_prototype(
                 mc,
-                JsObject::from_object_and_vtable_in(
+                JsObject::from_object_and_vtable(
                     mc,
                     Object::<OrdinaryObject>::default(),
                     &IMMUTABLE_PROTOTYPE_EXOTIC_INTERNAL_METHODS,
@@ -238,22 +229,22 @@ impl StandardConstructors {
             },
             async_function: StandardConstructor::uninit(mc),
             generator_function: StandardConstructor::uninit(mc),
-            array: StandardConstructor::with_prototype_in(
+            array: StandardConstructor::with_prototype(
                 mc,
-                JsObject::from_proto_and_data_in(mc, None, Array),
+                JsObject::from_proto_and_data(mc, None, Array),
             ),
             bigint: StandardConstructor::uninit(mc),
-            number: StandardConstructor::with_prototype_in(
+            number: StandardConstructor::with_prototype(
                 mc,
-                JsObject::from_proto_and_data_in(mc, None, 0.0),
+                JsObject::from_proto_and_data(mc, None, 0.0),
             ),
-            boolean: StandardConstructor::with_prototype_in(
+            boolean: StandardConstructor::with_prototype(
                 mc,
-                JsObject::from_proto_and_data_in(mc, None, false),
+                JsObject::from_proto_and_data(mc, None, false),
             ),
-            string: StandardConstructor::with_prototype_in(
+            string: StandardConstructor::with_prototype(
                 mc,
-                JsObject::from_proto_and_data_in(mc, None, js_string!()),
+                JsObject::from_proto_and_data(mc, None, js_string!()),
             ),
             regexp: StandardConstructor::uninit(mc),
             symbol: StandardConstructor::uninit(mc),
@@ -1189,16 +1180,16 @@ impl IntrinsicObjects {
     #[allow(clippy::unnecessary_wraps)]
     pub(crate) fn uninit(mc: &boa_gc::MutationContext<'static, '_>) -> Option<Self> {
         Some(Self {
-            reflect: JsObject::with_null_proto_in(mc),
-            math: JsObject::with_null_proto_in(mc),
-            json: JsObject::with_null_proto_in(mc),
+            reflect: JsObject::with_null_proto(mc),
+            math: JsObject::with_null_proto(mc),
+            json: JsObject::with_null_proto(mc),
             throw_type_error: JsFunction::empty_intrinsic_function_in(mc, false),
             array_prototype_values: JsFunction::empty_intrinsic_function_in(mc, false),
             array_prototype_to_string: JsFunction::empty_intrinsic_function_in(mc, false),
             iterator_prototypes: IteratorPrototypes::uninit_in(mc),
-            generator: JsObject::with_null_proto_in(mc),
-            async_generator: JsObject::with_null_proto_in(mc),
-            atomics: JsObject::with_null_proto_in(mc),
+            generator: JsObject::with_null_proto(mc),
+            async_generator: JsObject::with_null_proto(mc),
+            atomics: JsObject::with_null_proto(mc),
             eval: JsFunction::empty_intrinsic_function_in(mc, false),
             uri_functions: UriFunctions::uninit_in(mc),
             is_finite: JsFunction::empty_intrinsic_function_in(mc, false),
@@ -1210,13 +1201,13 @@ impl IntrinsicObjects {
             #[cfg(feature = "annex-b")]
             unescape: JsFunction::empty_intrinsic_function_in(mc, false),
             #[cfg(feature = "intl")]
-            intl: JsObject::new_unique(None, Intl::new()?),
+            intl: JsObject::new_unique(mc, None, Intl::new()?),
             #[cfg(feature = "intl")]
-            segments_prototype: JsObject::with_null_proto(),
+            segments_prototype: JsObject::with_null_proto(mc),
             #[cfg(feature = "temporal")]
-            temporal: JsObject::with_null_proto(),
+            temporal: JsObject::with_null_proto(mc),
             #[cfg(feature = "temporal")]
-            now: JsObject::with_null_proto(),
+            now: JsObject::with_null_proto(mc),
         })
     }
 
@@ -1466,46 +1457,46 @@ impl ObjectTemplates {
 
         // pre-initialize used shapes.
         let ordinary_object =
-            ObjectTemplate::with_prototype_in(mc, root_shape, constructors.object().prototype());
+            ObjectTemplate::with_prototype(mc, root_shape, constructors.object().prototype());
         let mut array = ObjectTemplate::new(root_shape);
         let length_property_key: PropertyKey = js_string!("length").into();
-        array.property_in(
+        array.property(
             mc,
             length_property_key.clone(),
             Attribute::WRITABLE | Attribute::PERMANENT | Attribute::NON_ENUMERABLE,
         );
-        array.set_prototype_in(mc, constructors.array().prototype());
+        array.set_prototype(mc, constructors.array().prototype());
 
         let number =
-            ObjectTemplate::with_prototype_in(mc, root_shape, constructors.number().prototype());
+            ObjectTemplate::with_prototype(mc, root_shape, constructors.number().prototype());
         let symbol =
-            ObjectTemplate::with_prototype_in(mc, root_shape, constructors.symbol().prototype());
+            ObjectTemplate::with_prototype(mc, root_shape, constructors.symbol().prototype());
         let bigint =
-            ObjectTemplate::with_prototype_in(mc, root_shape, constructors.bigint().prototype());
+            ObjectTemplate::with_prototype(mc, root_shape, constructors.bigint().prototype());
         let boolean =
-            ObjectTemplate::with_prototype_in(mc, root_shape, constructors.boolean().prototype());
+            ObjectTemplate::with_prototype(mc, root_shape, constructors.boolean().prototype());
         let mut string = ObjectTemplate::new(root_shape);
-        string.property_in(
+        string.property(
             mc,
             length_property_key.clone(),
             Attribute::READONLY | Attribute::PERMANENT | Attribute::NON_ENUMERABLE,
         );
-        string.set_prototype_in(mc, constructors.string().prototype());
+        string.set_prototype(mc, constructors.string().prototype());
 
         let mut regexp_without_proto = ObjectTemplate::new(root_shape);
-        regexp_without_proto.property_in(mc, js_string!("lastIndex").into(), Attribute::WRITABLE);
+        regexp_without_proto.property(mc, js_string!("lastIndex").into(), Attribute::WRITABLE);
 
         let mut regexp = regexp_without_proto.clone();
-        regexp.set_prototype_in(mc, constructors.regexp().prototype());
+        regexp.set_prototype(mc, constructors.regexp().prototype());
 
         let name_property_key: PropertyKey = js_string!("name").into();
         let mut function = ObjectTemplate::new(root_shape);
-        function.property_in(
+        function.property(
             mc,
             length_property_key.clone(),
             Attribute::READONLY | Attribute::CONFIGURABLE | Attribute::NON_ENUMERABLE,
         );
-        function.property_in(
+        function.property(
             mc,
             name_property_key,
             Attribute::READONLY | Attribute::CONFIGURABLE | Attribute::NON_ENUMERABLE,
@@ -1515,7 +1506,7 @@ impl ObjectTemplates {
         let mut async_function = function.clone();
         let mut function_with_prototype = function.clone();
 
-        function_with_prototype.property_in(
+        function_with_prototype.property(
             mc,
             PROTOTYPE.into(),
             Attribute::WRITABLE | Attribute::PERMANENT | Attribute::NON_ENUMERABLE,
@@ -1525,15 +1516,15 @@ impl ObjectTemplates {
 
         let function_with_prototype_without_proto = function_with_prototype.clone();
 
-        function.set_prototype_in(mc, constructors.function().prototype());
-        function_with_prototype.set_prototype_in(mc, constructors.function().prototype());
-        async_function.set_prototype_in(mc, constructors.async_function().prototype());
-        generator_function.set_prototype_in(mc, constructors.generator_function().prototype());
+        function.set_prototype(mc, constructors.function().prototype());
+        function_with_prototype.set_prototype(mc, constructors.function().prototype());
+        async_function.set_prototype(mc, constructors.async_function().prototype());
+        generator_function.set_prototype(mc, constructors.generator_function().prototype());
         async_generator_function
-            .set_prototype_in(mc, constructors.async_generator_function().prototype());
+            .set_prototype(mc, constructors.async_generator_function().prototype());
 
         let mut function_prototype = ordinary_object.clone();
-        function_prototype.property_in(
+        function_prototype.property(
             mc,
             CONSTRUCTOR.into(),
             Attribute::WRITABLE | Attribute::CONFIGURABLE | Attribute::NON_ENUMERABLE,
@@ -1543,7 +1534,7 @@ impl ObjectTemplates {
 
         // 4. Perform DefinePropertyOrThrow(obj, "length", PropertyDescriptor { [[Value]]: 𝔽(len),
         // [[Writable]]: true, [[Enumerable]]: false, [[Configurable]]: true }).
-        unmapped_arguments.property_in(
+        unmapped_arguments.property(
             mc,
             length_property_key,
             Attribute::WRITABLE | Attribute::NON_ENUMERABLE | Attribute::CONFIGURABLE,
@@ -1552,7 +1543,7 @@ impl ObjectTemplates {
         // 7. Perform ! DefinePropertyOrThrow(obj, @@iterator, PropertyDescriptor {
         // [[Value]]: %Array.prototype.values%, [[Writable]]: true, [[Enumerable]]: false,
         // [[Configurable]]: true }).
-        unmapped_arguments.property_in(
+        unmapped_arguments.property(
             mc,
             JsSymbol::iterator().into(),
             Attribute::WRITABLE | Attribute::NON_ENUMERABLE | Attribute::CONFIGURABLE,
@@ -1563,7 +1554,7 @@ impl ObjectTemplates {
         // 8. Perform ! DefinePropertyOrThrow(obj, "callee", PropertyDescriptor {
         // [[Get]]: %ThrowTypeError%, [[Set]]: %ThrowTypeError%, [[Enumerable]]: false,
         // [[Configurable]]: false }).
-        unmapped_arguments.accessor_in(
+        unmapped_arguments.accessor(
             mc,
             js_string!("callee").into(),
             true,
@@ -1573,37 +1564,37 @@ impl ObjectTemplates {
 
         // 21. Perform ! DefinePropertyOrThrow(obj, "callee", PropertyDescriptor {
         // [[Value]]: func, [[Writable]]: true, [[Enumerable]]: false, [[Configurable]]: true }).
-        mapped_arguments.property_in(
+        mapped_arguments.property(
             mc,
             js_string!("callee").into(),
             Attribute::WRITABLE | Attribute::NON_ENUMERABLE | Attribute::CONFIGURABLE,
         );
 
         let mut iterator_result = ordinary_object.clone();
-        iterator_result.property_in(
+        iterator_result.property(
             mc,
             js_string!("value").into(),
             Attribute::WRITABLE | Attribute::CONFIGURABLE | Attribute::ENUMERABLE,
         );
-        iterator_result.property_in(
+        iterator_result.property(
             mc,
             js_string!("done").into(),
             Attribute::WRITABLE | Attribute::CONFIGURABLE | Attribute::ENUMERABLE,
         );
 
         let mut namespace = ObjectTemplate::new(root_shape);
-        namespace.property_in(mc, JsSymbol::to_string_tag().into(), Attribute::empty());
+        namespace.property(mc, JsSymbol::to_string_tag().into(), Attribute::empty());
 
         let with_resolvers = {
             let mut with_resolvers = ordinary_object.clone();
 
             with_resolvers
                 // 4. Perform ! CreateDataPropertyOrThrow(obj, "promise", promiseCapability.[[Promise]]).
-                .property_in(mc, js_string!("promise").into(), Attribute::all())
+                .property(mc, js_string!("promise").into(), Attribute::all())
                 // 5. Perform ! CreateDataPropertyOrThrow(obj, "resolve", promiseCapability.[[Resolve]]).
-                .property_in(mc, js_string!("resolve").into(), Attribute::all())
+                .property(mc, js_string!("resolve").into(), Attribute::all())
                 // 6. Perform ! CreateDataPropertyOrThrow(obj, "reject", promiseCapability.[[Reject]]).
-                .property_in(mc, js_string!("reject").into(), Attribute::all());
+                .property(mc, js_string!("reject").into(), Attribute::all());
 
             with_resolvers
         };
@@ -1611,8 +1602,8 @@ impl ObjectTemplates {
         let wait_async = {
             let mut obj = ordinary_object.clone();
 
-            obj.property_in(mc, js_string!("async").into(), Attribute::all())
-                .property_in(mc, js_string!("value").into(), Attribute::all());
+            obj.property(mc, js_string!("async").into(), Attribute::all())
+                .property(mc, js_string!("value").into(), Attribute::all());
 
             obj
         };
diff --git a/core/engine/src/context/mod.rs b/core/engine/src/context/mod.rs
index 218d177ffda..a84ebd8fa41 100644
--- a/core/engine/src/context/mod.rs
+++ b/core/engine/src/context/mod.rs
@@ -291,7 +291,7 @@ impl Context {
         length: usize,
         body: NativeFunction,
     ) -> JsResult<()> {
-        let function = FunctionObjectBuilder::new(self.realm(), body)
+        let function = FunctionObjectBuilder::new(self.realm(), self.gc_collector(), body)
             .name(name.clone())
             .length(length)
             .constructor(true)
@@ -324,7 +324,7 @@ impl Context {
         length: usize,
         body: NativeFunction,
     ) -> JsResult<()> {
-        let function = FunctionObjectBuilder::new(self.realm(), body)
+        let function = FunctionObjectBuilder::new(self.realm(), self.gc_collector(), body)
             .name(name.clone())
             .length(length)
             .constructor(false)
@@ -1225,7 +1225,7 @@ impl ContextBuilder {
         }
 
         let mc = unsafe { boa_gc::MutationContext::global() };
-        let root_shape = RootShape::new_in(&mc);
+        let root_shape = RootShape::new(&mc);
 
         let host_hooks = self.host_hooks.unwrap_or(Rc::new(DefaultHooks));
         let clock = self.clock.unwrap_or_else(|| Rc::new(StdClock::new()));
diff --git a/core/engine/src/error/mod.rs b/core/engine/src/error/mod.rs
index 2e8ec0e6949..00e1a3a03d7 100644
--- a/core/engine/src/error/mod.rs
+++ b/core/engine/src/error/mod.rs
@@ -1346,6 +1346,7 @@ impl JsNativeError {
         };
 
         let o = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             prototype,
             Error::with_stack(tag, stack.0.clone()),
diff --git a/core/engine/src/module/mod.rs b/core/engine/src/module/mod.rs
index 1f6d01948fd..01c9d8f7a45 100644
--- a/core/engine/src/module/mod.rs
+++ b/core/engine/src/module/mod.rs
@@ -658,7 +658,7 @@ impl Module {
                         },
                         self.clone(),
                     )
-                    .to_js_function(context.realm()),
+                    .to_js_function(context.realm(), context.gc_collector()),
                 ),
                 None,
                 context,
@@ -670,7 +670,7 @@ impl Module {
                         |_, _, module, context| Ok(module.evaluate(context)?.into()),
                         self.clone(),
                     )
-                    .to_js_function(context.realm()),
+                    .to_js_function(context.realm(), context.gc_collector()),
                 ),
                 None,
                 context,
@@ -784,8 +784,12 @@ impl<T: IntoIterator<Item = (JsString, NativeFunction)> + Clone> IntoJsModule fo
             unsafe {
                 SyntheticModuleInitializer::from_closure(move |module, context| {
                     for (name, f) in names.iter().zip(fns.iter()) {
-                        module
-                            .set_export(name, f.clone().to_js_function(context.realm()).into())?;
+                        module.set_export(
+                            name,
+                            f.clone()
+                                .to_js_function(context.realm(), context.gc_collector())
+                                .into(),
+                        )?;
                     }
                     Ok(())
                 })
diff --git a/core/engine/src/module/namespace.rs b/core/engine/src/module/namespace.rs
index f42692c9f1d..ea860363ce5 100644
--- a/core/engine/src/module/namespace.rs
+++ b/core/engine/src/module/namespace.rs
@@ -100,6 +100,7 @@ impl ModuleNamespace {
 
         // 10. Return M.
         context.intrinsics().templates().namespace().create(
+            context.gc_collector(),
             Self {
                 module,
                 exports,
diff --git a/core/engine/src/module/source.rs b/core/engine/src/module/source.rs
index c7962cc5b32..26adadc14d7 100644
--- a/core/engine/src/module/source.rs
+++ b/core/engine/src/module/source.rs
@@ -1477,6 +1477,7 @@ impl SourceTextModule {
         // 5. Let onFulfilled be CreateBuiltinFunction(fulfilledClosure, 0, "", « »).
         let on_fulfilled = FunctionObjectBuilder::new(
             context.realm(),
+            context.gc_collector(),
             NativeFunction::from_copy_closure_with_captures(
                 |_, _, module, context| {
                     //     a. Perform AsyncModuleExecutionFulfilled(module).
@@ -1493,6 +1494,7 @@ impl SourceTextModule {
         // 7. Let onRejected be CreateBuiltinFunction(rejectedClosure, 0, "", « »).
         let on_rejected = FunctionObjectBuilder::new(
             context.realm(),
+            context.gc_collector(),
             NativeFunction::from_copy_closure_with_captures(
                 |_, args, module, context| {
                     let error = JsError::from_opaque(args.get_or_undefined(0).clone());
diff --git a/core/engine/src/native_function/mod.rs b/core/engine/src/native_function/mod.rs
index 11dc49adce8..86e9d141160 100644
--- a/core/engine/src/native_function/mod.rs
+++ b/core/engine/src/native_function/mod.rs
@@ -312,8 +312,12 @@ impl NativeFunction {
     ///
     /// Useful to create functions that will only be used once, such as callbacks.
     #[must_use]
-    pub fn to_js_function(self, realm: &Realm) -> JsFunction {
-        FunctionObjectBuilder::new(realm, self).build()
+    pub fn to_js_function(
+        self,
+        realm: &Realm,
+        mc: &boa_gc::MutationContext<'static, '_>,
+    ) -> JsFunction {
+        FunctionObjectBuilder::new(realm, mc, self).build()
     }
 }
 
@@ -443,6 +447,7 @@ fn native_function_construct(
                         context,
                     )?;
                     Ok(JsObject::from_proto_and_data_with_shared_shape(
+                        context.gc_collector(),
                         context.root_shape(),
                         prototype,
                         OrdinaryObject,
diff --git a/core/engine/src/object/builtins/jsarraybuffer.rs b/core/engine/src/object/builtins/jsarraybuffer.rs
index b377f684dee..3ea14c087dc 100644
--- a/core/engine/src/object/builtins/jsarraybuffer.rs
+++ b/core/engine/src/object/builtins/jsarraybuffer.rs
@@ -124,6 +124,7 @@ impl JsArrayBuffer {
         // 3. Set obj.[[ArrayBufferData]] to block.
         // 4. Set obj.[[ArrayBufferByteLength]] to byteLength.
         let obj = JsObject::new(
+            context.gc_collector(),
             context.root_shape(),
             prototype,
             ArrayBuffer::from_data(block, JsValue::undefined()),
diff --git a/core/engine/src/object/builtins/jsdataview.rs b/core/engine/src/object/builtins/jsdataview.rs
index 7bf07ade92d..c059cacebcf 100644
--- a/core/engine/src/object/builtins/jsdataview.rs
+++ b/core/engine/src/object/builtins/jsdataview.rs
@@ -135,6 +135,7 @@ impl JsDataView {
         }
 
         let obj = JsObject::new(
+            context.gc_collector(),
             context.root_shape(),
             prototype,
             DataView {
diff --git a/core/engine/src/object/builtins/jsdate.rs b/core/engine/src/object/builtins/jsdate.rs
index 3a056242f9b..59e9830795a 100644
--- a/core/engine/src/object/builtins/jsdate.rs
+++ b/core/engine/src/object/builtins/jsdate.rs
@@ -45,9 +45,13 @@ impl JsDate {
     pub fn new(context: &mut Context) -> Self {
         let prototype = context.intrinsics().constructors().date().prototype();
         let now = Date::utc_now(context);
-        let inner =
-            JsObject::from_proto_and_data_with_shared_shape(context.root_shape(), prototype, now)
-                .upcast();
+        let inner = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
+            context.root_shape(),
+            prototype,
+            now,
+        )
+        .upcast();
 
         Self { inner }
     }
@@ -552,6 +556,7 @@ impl JsDate {
 
         Ok(Self {
             inner: JsObject::from_proto_and_data_with_shared_shape(
+                context.gc_collector(),
                 context.root_shape(),
                 prototype,
                 date_time,
diff --git a/core/engine/src/object/builtins/jsfunction.rs b/core/engine/src/object/builtins/jsfunction.rs
index 0d165e0c17c..8e76b155ad3 100644
--- a/core/engine/src/object/builtins/jsfunction.rs
+++ b/core/engine/src/object/builtins/jsfunction.rs
@@ -128,7 +128,7 @@ impl JsFunction {
         constructor: bool,
     ) -> Self {
         Self {
-            inner: JsObject::from_proto_and_data_in(
+            inner: JsObject::from_proto_and_data(
                 mc,
                 None,
                 NativeFunctionObject {
diff --git a/core/engine/src/object/builtins/jsmap.rs b/core/engine/src/object/builtins/jsmap.rs
index c35a014cdbf..e90ef3db208 100644
--- a/core/engine/src/object/builtins/jsmap.rs
+++ b/core/engine/src/object/builtins/jsmap.rs
@@ -155,6 +155,7 @@ impl JsMap {
     /// # let context = &mut Context::default();
     /// // `some_object` can be any JavaScript `Map` object.
     /// let some_object = JsObject::from_proto_and_data(
+    ///     context.gc_collector(),
     ///     context.intrinsics().constructors().map().prototype(),
     ///     OrderedMap::<JsValue>::new(),
     /// );
@@ -198,6 +199,7 @@ impl JsMap {
 
         // Create a default map object with [[MapData]] as a new empty list
         JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             prototype,
             <OrderedMap<JsValue>>::new(),
diff --git a/core/engine/src/object/builtins/jspromise.rs b/core/engine/src/object/builtins/jspromise.rs
index 08e7af96556..fef2ce9811f 100644
--- a/core/engine/src/object/builtins/jspromise.rs
+++ b/core/engine/src/object/builtins/jspromise.rs
@@ -62,7 +62,7 @@ use std::{future::Future, pin::Pin, task};
 ///                 Err(JsError::from_opaque(args.get_or_undefined(0).clone())
 ///                     .into())
 ///             })
-///             .to_js_function(context.realm()),
+///             .to_js_function(context.realm(), context.gc_collector()),
 ///         ),
 ///         None,
 ///         context,
@@ -71,7 +71,7 @@ use std::{future::Future, pin::Pin, task};
 ///         NativeFunction::from_fn_ptr(|_, args, _| {
 ///             Ok(args.get_or_undefined(0).clone())
 ///         })
-///         .to_js_function(context.realm()),
+///         .to_js_function(context.realm(), context.gc_collector()),
 ///         context,
 ///     )?
 ///     .finally(
@@ -84,7 +84,7 @@ use std::{future::Future, pin::Pin, task};
 ///             )?;
 ///             Ok(JsValue::undefined())
 ///         })
-///         .to_js_function(context.realm()),
+///         .to_js_function(context.realm(), context.gc_collector()),
 ///         context,
 ///     )?;
 ///
@@ -168,6 +168,7 @@ impl JsPromise {
         F: FnOnce(&ResolvingFunctions, &mut Context) -> JsResult<JsValue>,
     {
         let promise = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             context.intrinsics().constructors().promise().prototype(),
             Promise::new(),
@@ -219,6 +220,7 @@ impl JsPromise {
     #[inline]
     pub fn new_pending(context: &mut Context) -> (Self, ResolvingFunctions) {
         let promise = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             context.intrinsics().constructors().promise().prototype(),
             Promise::new(),
@@ -255,7 +257,7 @@ impl JsPromise {
     ///     PromiseState::Fulfilled(JsValue::undefined())
     /// );
     ///
-    /// assert!(JsPromise::from_object(JsObject::with_null_proto()).is_err());
+    /// assert!(JsPromise::from_object(JsObject::with_null_proto(context.gc_collector())).is_err());
     ///
     /// # Ok(())
     /// # }
@@ -541,7 +543,7 @@ impl JsPromise {
     ///                 .to_string(context)
     ///                 .map(JsValue::from)
     ///         })
-    ///         .to_js_function(context.realm()),
+    ///         .to_js_function(context.realm(), context.gc_collector()),
     ///     ),
     ///     None,
     ///     context,
@@ -611,7 +613,7 @@ impl JsPromise {
     ///             .to_string(context)
     ///             .map(JsValue::from)
     ///     })
-    ///     .to_js_function(context.realm()),
+    ///     .to_js_function(context.realm(), context.gc_collector()),
     ///     context,
     /// )?;
     ///
@@ -685,7 +687,7 @@ impl JsPromise {
     ///         )?;
     ///         Ok(JsValue::undefined())
     ///     })
-    ///     .to_js_function(context.realm()),
+    ///     .to_js_function(context.realm(), context.gc_collector()),
     ///     context,
     /// )?;
     ///
@@ -1125,8 +1127,8 @@ impl JsPromise {
         };
 
         drop(self.then(
-            Some(resolve.to_js_function(context.realm())),
-            Some(reject.to_js_function(context.realm())),
+            Some(resolve.to_js_function(context.realm(), context.gc_collector())),
+            Some(reject.to_js_function(context.realm(), context.gc_collector())),
             context,
         )?);
 
@@ -1165,7 +1167,7 @@ impl JsPromise {
     ///             assert_eq!(*args.get_or_undefined(0), JsValue::new(1));
     ///             Ok(JsValue::new(2))
     ///         })
-    ///         .to_js_function(context.realm()),
+    ///         .to_js_function(context.realm(), context.gc_collector()),
     ///     ),
     ///     None,
     ///     context,
@@ -1192,7 +1194,7 @@ impl JsPromise {
     ///         NativeFunction::from_fn_ptr(|_, _, _| {
     ///             panic!("This will not happen.");
     ///         })
-    ///         .to_js_function(context.realm()),
+    ///         .to_js_function(context.realm(), context.gc_collector()),
     ///     ),
     ///     None,
     ///     context,
@@ -1241,6 +1243,7 @@ impl JsPromise {
         // 4. Let onFulfilled be CreateBuiltinFunction(fulfilledClosure, 1, "", « »).
         let on_fulfilled = FunctionObjectBuilder::new(
             context.realm(),
+            context.gc_collector(),
             NativeFunction::from_copy_closure_with_captures(
                 |_this, args, captures, context| {
                     // a. Let prevContext be the running execution context.
@@ -1305,6 +1308,7 @@ impl JsPromise {
         // 6. Let onRejected be CreateBuiltinFunction(rejectedClosure, 1, "", « »).
         let on_rejected = FunctionObjectBuilder::new(
             context.realm(),
+            context.gc_collector(),
             NativeFunction::from_copy_closure_with_captures(
                 |_this, args, captures, context| {
                     // a. Let prevContext be the running execution context.
diff --git a/core/engine/src/object/builtins/jsproxy.rs b/core/engine/src/object/builtins/jsproxy.rs
index 145d6196f21..f8b17c8c294 100644
--- a/core/engine/src/object/builtins/jsproxy.rs
+++ b/core/engine/src/object/builtins/jsproxy.rs
@@ -394,21 +394,28 @@ impl JsProxyBuilder {
     /// [`JsObject`] in case there's a need to manipulate the returned object
     /// inside Rust code.
     pub fn build(self, context: &mut Context) -> JsResult<JsProxy> {
-        let handler = JsObject::with_object_proto(context.intrinsics());
+        let handler = JsObject::with_object_proto(context.gc_collector(), context.intrinsics());
 
         if let Some(apply) = self.apply {
-            let f = FunctionObjectBuilder::new(context.realm(), NativeFunction::from_fn_ptr(apply))
-                .length(3)
-                .build();
+            let f = FunctionObjectBuilder::new(
+                context.realm(),
+                context.gc_collector(),
+                NativeFunction::from_fn_ptr(apply),
+            )
+            .length(3)
+            .build();
             handler
                 .create_data_property_or_throw(js_string!("apply"), f, context)
                 .js_expect("new object should be writable")?;
         }
         if let Some(construct) = self.construct {
-            let f =
-                FunctionObjectBuilder::new(context.realm(), NativeFunction::from_fn_ptr(construct))
-                    .length(3)
-                    .build();
+            let f = FunctionObjectBuilder::new(
+                context.realm(),
+                context.gc_collector(),
+                NativeFunction::from_fn_ptr(construct),
+            )
+            .length(3)
+            .build();
             handler
                 .create_data_property_or_throw(js_string!("construct"), f, context)
                 .js_expect("new object should be writable")?;
@@ -416,6 +423,7 @@ impl JsProxyBuilder {
         if let Some(define_property) = self.define_property {
             let f = FunctionObjectBuilder::new(
                 context.realm(),
+                context.gc_collector(),
                 NativeFunction::from_fn_ptr(define_property),
             )
             .length(3)
@@ -427,6 +435,7 @@ impl JsProxyBuilder {
         if let Some(delete_property) = self.delete_property {
             let f = FunctionObjectBuilder::new(
                 context.realm(),
+                context.gc_collector(),
                 NativeFunction::from_fn_ptr(delete_property),
             )
             .length(2)
@@ -436,9 +445,13 @@ impl JsProxyBuilder {
                 .js_expect("new object should be writable")?;
         }
         if let Some(get) = self.get {
-            let f = FunctionObjectBuilder::new(context.realm(), NativeFunction::from_fn_ptr(get))
-                .length(3)
-                .build();
+            let f = FunctionObjectBuilder::new(
+                context.realm(),
+                context.gc_collector(),
+                NativeFunction::from_fn_ptr(get),
+            )
+            .length(3)
+            .build();
             handler
                 .create_data_property_or_throw(js_string!("get"), f, context)
                 .js_expect("new object should be writable")?;
@@ -446,6 +459,7 @@ impl JsProxyBuilder {
         if let Some(get_own_property_descriptor) = self.get_own_property_descriptor {
             let f = FunctionObjectBuilder::new(
                 context.realm(),
+                context.gc_collector(),
                 NativeFunction::from_fn_ptr(get_own_property_descriptor),
             )
             .length(2)
@@ -457,6 +471,7 @@ impl JsProxyBuilder {
         if let Some(get_prototype_of) = self.get_prototype_of {
             let f = FunctionObjectBuilder::new(
                 context.realm(),
+                context.gc_collector(),
                 NativeFunction::from_fn_ptr(get_prototype_of),
             )
             .length(1)
@@ -466,9 +481,13 @@ impl JsProxyBuilder {
                 .js_expect("new object should be writable")?;
         }
         if let Some(has) = self.has {
-            let f = FunctionObjectBuilder::new(context.realm(), NativeFunction::from_fn_ptr(has))
-                .length(2)
-                .build();
+            let f = FunctionObjectBuilder::new(
+                context.realm(),
+                context.gc_collector(),
+                NativeFunction::from_fn_ptr(has),
+            )
+            .length(2)
+            .build();
             handler
                 .create_data_property_or_throw(js_string!("has"), f, context)
                 .js_expect("new object should be writable")?;
@@ -476,6 +495,7 @@ impl JsProxyBuilder {
         if let Some(is_extensible) = self.is_extensible {
             let f = FunctionObjectBuilder::new(
                 context.realm(),
+                context.gc_collector(),
                 NativeFunction::from_fn_ptr(is_extensible),
             )
             .length(1)
@@ -485,10 +505,13 @@ impl JsProxyBuilder {
                 .js_expect("new object should be writable")?;
         }
         if let Some(own_keys) = self.own_keys {
-            let f =
-                FunctionObjectBuilder::new(context.realm(), NativeFunction::from_fn_ptr(own_keys))
-                    .length(1)
-                    .build();
+            let f = FunctionObjectBuilder::new(
+                context.realm(),
+                context.gc_collector(),
+                NativeFunction::from_fn_ptr(own_keys),
+            )
+            .length(1)
+            .build();
             handler
                 .create_data_property_or_throw(js_string!("ownKeys"), f, context)
                 .js_expect("new object should be writable")?;
@@ -496,6 +519,7 @@ impl JsProxyBuilder {
         if let Some(prevent_extensions) = self.prevent_extensions {
             let f = FunctionObjectBuilder::new(
                 context.realm(),
+                context.gc_collector(),
                 NativeFunction::from_fn_ptr(prevent_extensions),
             )
             .length(1)
@@ -505,9 +529,13 @@ impl JsProxyBuilder {
                 .js_expect("new object should be writable")?;
         }
         if let Some(set) = self.set {
-            let f = FunctionObjectBuilder::new(context.realm(), NativeFunction::from_fn_ptr(set))
-                .length(4)
-                .build();
+            let f = FunctionObjectBuilder::new(
+                context.realm(),
+                context.gc_collector(),
+                NativeFunction::from_fn_ptr(set),
+            )
+            .length(4)
+            .build();
             handler
                 .create_data_property_or_throw(js_string!("set"), f, context)
                 .js_expect("new object should be writable")?;
@@ -515,6 +543,7 @@ impl JsProxyBuilder {
         if let Some(set_prototype_of) = self.set_prototype_of {
             let f = FunctionObjectBuilder::new(
                 context.realm(),
+                context.gc_collector(),
                 NativeFunction::from_fn_ptr(set_prototype_of),
             )
             .length(2)
@@ -525,6 +554,7 @@ impl JsProxyBuilder {
         }
 
         let proxy = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             context.intrinsics().constructors().object().prototype(),
             Proxy::new(self.target, handler),
diff --git a/core/engine/src/object/builtins/jsset.rs b/core/engine/src/object/builtins/jsset.rs
index 01efe9407d6..09f9554c036 100644
--- a/core/engine/src/object/builtins/jsset.rs
+++ b/core/engine/src/object/builtins/jsset.rs
@@ -29,6 +29,7 @@ impl JsSet {
     pub fn new(context: &mut Context) -> Self {
         Self {
             inner: JsObject::from_proto_and_data_with_shared_shape(
+                context.gc_collector(),
                 context.root_shape(),
                 context.intrinsics().constructors().set().prototype(),
                 OrderedSet::new(),
@@ -179,6 +180,7 @@ impl JsSet {
 
         Self {
             inner: JsObject::from_proto_and_data_with_shared_shape(
+                context.gc_collector(),
                 context.root_shape(),
                 context.intrinsics().constructors().set().prototype(),
                 set,
diff --git a/core/engine/src/object/builtins/jssharedarraybuffer.rs b/core/engine/src/object/builtins/jssharedarraybuffer.rs
index 36b2453211b..76481653359 100644
--- a/core/engine/src/object/builtins/jssharedarraybuffer.rs
+++ b/core/engine/src/object/builtins/jssharedarraybuffer.rs
@@ -58,7 +58,7 @@ impl JsSharedArrayBuffer {
             .shared_array_buffer()
             .prototype();
 
-        let inner = JsObject::new(context.root_shape(), proto, buffer);
+        let inner = JsObject::new(context.gc_collector(), context.root_shape(), proto, buffer);
 
         Self { inner }
     }
diff --git a/core/engine/src/object/builtins/jstypedarray.rs b/core/engine/src/object/builtins/jstypedarray.rs
index 90d94d7387e..eaa250230a4 100644
--- a/core/engine/src/object/builtins/jstypedarray.rs
+++ b/core/engine/src/object/builtins/jstypedarray.rs
@@ -516,8 +516,7 @@ impl JsTypedArray {
     /// let array = JsUint8Array::from_iter(data, context)?;
     ///
     /// let greater_than_10_predicate = FunctionObjectBuilder::new(
-    ///     context.realm(),
-    ///     NativeFunction::from_fn_ptr(|_this, args, _context| {
+    ///     context.realm(), ///     NativeFunction::from_fn_ptr(|_this, args, _context| {
     ///         let element = args
     ///             .first()
     ///             .cloned()
@@ -574,8 +573,7 @@ impl JsTypedArray {
     /// let array = JsUint8Array::from_iter(data, context)?;
     ///
     /// let lower_than_200_predicate = FunctionObjectBuilder::new(
-    ///     context.realm(),
-    ///     NativeFunction::from_fn_ptr(|_this, args, _context| {
+    ///     context.realm(), ///     NativeFunction::from_fn_ptr(|_this, args, _context| {
     ///         let element = args
     ///             .first()
     ///             .cloned()
@@ -624,8 +622,7 @@ impl JsTypedArray {
     /// let array = JsUint8Array::from_iter(data, context)?;
     ///
     /// let lower_than_200_predicate = FunctionObjectBuilder::new(
-    ///     context.realm(),
-    ///     NativeFunction::from_fn_ptr(|_this, args, _context| {
+    ///     context.realm(), ///     NativeFunction::from_fn_ptr(|_this, args, _context| {
     ///         let element = args
     ///             .first()
     ///             .cloned()
@@ -681,8 +678,7 @@ impl JsTypedArray {
     /// let num_to_modify = context.alloc(GcRefCell::new(0u8));
     ///
     /// let js_function = FunctionObjectBuilder::new(
-    ///     context.realm(),
-    ///     NativeFunction::from_copy_closure_with_captures(
+    ///     context.realm(), ///     NativeFunction::from_copy_closure_with_captures(
     ///         |_, args, captures, inner_context| {
     ///             let element = args
     ///                 .first()
diff --git a/core/engine/src/object/builtins/jsweakmap.rs b/core/engine/src/object/builtins/jsweakmap.rs
index 9fdd2e8327c..bad6925a7f1 100644
--- a/core/engine/src/object/builtins/jsweakmap.rs
+++ b/core/engine/src/object/builtins/jsweakmap.rs
@@ -28,6 +28,7 @@ impl JsWeakMap {
     pub fn new(context: &mut Context) -> Self {
         Self {
             inner: JsObject::from_proto_and_data_with_shared_shape(
+                context.gc_collector(),
                 context.root_shape(),
                 context.intrinsics().constructors().weak_map().prototype(),
                 NativeWeakMap::new(context.gc_collector()),
diff --git a/core/engine/src/object/builtins/jsweakset.rs b/core/engine/src/object/builtins/jsweakset.rs
index 663a3c65df0..d226066c290 100644
--- a/core/engine/src/object/builtins/jsweakset.rs
+++ b/core/engine/src/object/builtins/jsweakset.rs
@@ -28,6 +28,7 @@ impl JsWeakSet {
     pub fn new(context: &mut Context) -> Self {
         Self {
             inner: JsObject::from_proto_and_data_with_shared_shape(
+                context.gc_collector(),
                 context.root_shape(),
                 context.intrinsics().constructors().weak_set().prototype(),
                 NativeWeakSet::new(context.gc_collector()),
diff --git a/core/engine/src/object/datatypes.rs b/core/engine/src/object/datatypes.rs
index 9d62f28b99a..c8c3c9acb75 100644
--- a/core/engine/src/object/datatypes.rs
+++ b/core/engine/src/object/datatypes.rs
@@ -34,7 +34,7 @@ use super::internal_methods::{InternalObjectMethods, ORDINARY_INTERNAL_METHODS};
 /// }
 ///
 /// let object =
-///     JsObject::from_proto_and_data(None, CustomStruct { counter: 5 });
+///     JsObject::from_proto_and_data(context.gc_collector(), None, CustomStruct { counter: 5 });
 ///
 /// assert_eq!(object.downcast_ref::<CustomStruct>().unwrap().counter, 5);
 /// ```
diff --git a/core/engine/src/object/internal_methods/mod.rs b/core/engine/src/object/internal_methods/mod.rs
index 8e474b5dde5..e2c11a4f662 100644
--- a/core/engine/src/object/internal_methods/mod.rs
+++ b/core/engine/src/object/internal_methods/mod.rs
@@ -44,6 +44,11 @@ impl<'ctx> InternalMethodPropertyContext<'ctx> {
     pub(crate) fn slot(&mut self) -> &mut Slot {
         &mut self.slot
     }
+
+    #[inline]
+    pub(crate) fn slot_and_mc(&mut self) -> (&mut Slot, &boa_gc::MutationContext<'static, '_>) {
+        (&mut self.slot, self.context.gc_collector())
+    }
 }
 
 impl Deref for InternalMethodPropertyContext<'_> {
@@ -532,8 +537,9 @@ pub(crate) fn ordinary_get_prototype_of(
 pub(crate) fn ordinary_set_prototype_of(
     obj: &JsObject,
     val: JsPrototype,
-    _: &mut Context,
+    context: &mut Context,
 ) -> JsResult<bool> {
+    let mc = context.gc_collector();
     // 1. Assert: Either Type(V) is Object or Type(V) is Null.
     // 2. Let current be O.[[Prototype]].
     let current = obj.prototype();
@@ -573,7 +579,7 @@ pub(crate) fn ordinary_set_prototype_of(
     }
 
     // 9. Set O.[[Prototype]] to V.
-    obj.set_prototype(val);
+    obj.set_prototype(mc, val);
 
     // 10. Return true.
     Ok(true)
@@ -657,12 +663,14 @@ pub(crate) fn ordinary_define_own_property(
     let extensible = obj.__is_extensible__(context)?;
 
     // 3. Return ValidateAndApplyPropertyDescriptor(O, P, extensible, Desc, current).
+    let (slot, mc) = context.slot_and_mc();
     Ok(validate_and_apply_property_descriptor(
         Some((obj, key)),
         extensible,
         desc,
         current,
-        context.slot(),
+        slot,
+        mc,
     ))
 }
 
@@ -945,7 +953,7 @@ pub(crate) fn ordinary_delete(
             // 4. If desc.[[Configurable]] is true, then
             Some(desc) if desc.expect_configurable() => {
                 // a. Remove the own property with name P from O.
-                obj.borrow_mut().remove(key);
+                obj.borrow_mut().remove(context.gc_collector(), key);
                 // b. Return true.
                 true
             }
@@ -1004,7 +1012,16 @@ pub(crate) fn is_compatible_property_descriptor(
     current: Option<PropertyDescriptor>,
 ) -> bool {
     // 1. Return ValidateAndApplyPropertyDescriptor(undefined, undefined, Extensible, Desc, Current).
-    validate_and_apply_property_descriptor(None, extensible, desc, current, &mut Slot::new())
+    let mut dummy_slot = Slot::new();
+    let dummy_mc = unsafe { boa_gc::MutationContext::global() };
+    validate_and_apply_property_descriptor(
+        None,
+        extensible,
+        desc,
+        current,
+        &mut dummy_slot,
+        &dummy_mc,
+    )
 }
 
 /// Abstract operation `ValidateAndApplyPropertyDescriptor`
@@ -1019,6 +1036,7 @@ pub(crate) fn validate_and_apply_property_descriptor(
     desc: PropertyDescriptor,
     current: Option<PropertyDescriptor>,
     slot: &mut Slot,
+    mc: &boa_gc::MutationContext<'static, '_>,
 ) -> bool {
     // 1. Assert: If O is not undefined, then IsPropertyKey(P) is true.
 
@@ -1033,6 +1051,7 @@ pub(crate) fn validate_and_apply_property_descriptor(
 
         if let Some((obj, key)) = obj_and_key {
             obj.borrow_mut().properties.insert_with_slot(
+                mc,
                 key,
                 // c. If IsGenericDescriptor(Desc) is true or IsDataDescriptor(Desc) is true, then
                 if desc.is_generic_descriptor() || desc.is_data_descriptor() {
@@ -1153,7 +1172,7 @@ pub(crate) fn validate_and_apply_property_descriptor(
         current.fill_with(desc);
         obj.borrow_mut()
             .properties
-            .insert_with_slot(key, current, slot);
+            .insert_with_slot(mc, key, current, slot);
         slot.attributes |= SlotAttributes::FOUND;
     }
 
diff --git a/core/engine/src/object/jsobject.rs b/core/engine/src/object/jsobject.rs
index 10cfd824459..5827278464d 100644
--- a/core/engine/src/object/jsobject.rs
+++ b/core/engine/src/object/jsobject.rs
@@ -112,12 +112,12 @@ impl JsObject {
     /// ```
     #[inline]
     #[must_use]
-    pub fn default(intrinsics: &Intrinsics) -> Self {
-        Self::with_object_proto(intrinsics)
+    pub fn default(mc: &boa_gc::MutationContext<'static, '_>, intrinsics: &Intrinsics) -> Self {
+        Self::with_object_proto(mc, intrinsics)
     }
 
     /// Creates a new `JsObject` from its inner object and its vtable using the given context.
-    pub(crate) fn from_object_and_vtable_in<T: NativeObject>(
+    pub(crate) fn from_object_and_vtable<T: NativeObject>(
         mc: &boa_gc::MutationContext<'static, '_>,
         object: Object<T>,
         vtable: &'static InternalObjectMethods,
@@ -133,18 +133,6 @@ impl JsObject {
         JsObject { inner }.upcast()
     }
 
-    /// Creates a new `JsObject` from its inner object and its vtable.
-    pub(crate) fn from_object_and_vtable<T: NativeObject>(
-        object: Object<T>,
-        vtable: &'static InternalObjectMethods,
-    ) -> Self {
-        Self::from_object_and_vtable_in(
-            &unsafe { boa_gc::MutationContext::global() },
-            object,
-            vtable,
-        )
-    }
-
     /// Creates a new ordinary object with its prototype set to the `Object` prototype.
     ///
     /// This is equivalent to calling the specification's abstract operation
@@ -157,15 +145,19 @@ impl JsObject {
     /// ```
     /// # use boa_engine::{Context, JsObject};
     /// let context = &mut Context::default();
-    /// let obj = JsObject::with_object_proto(context.intrinsics());
+    /// let obj = JsObject::with_object_proto(context.gc_collector(), context.intrinsics());
     ///
     /// assert!(obj.is_ordinary());
     /// assert!(obj.prototype().is_some());
     /// ```
     #[inline]
     #[must_use]
-    pub fn with_object_proto(intrinsics: &Intrinsics) -> Self {
+    pub fn with_object_proto(
+        mc: &boa_gc::MutationContext<'static, '_>,
+        intrinsics: &Intrinsics,
+    ) -> Self {
         Self::from_proto_and_data(
+            mc,
             intrinsics.constructors().object().prototype(),
             OrdinaryObject,
         )
@@ -174,33 +166,12 @@ impl JsObject {
     /// Creates a new ordinary object, with its prototype set to null using the given context.
     #[inline]
     #[must_use]
-    pub fn with_null_proto_in(mc: &boa_gc::MutationContext<'static, '_>) -> Self {
-        Self::from_proto_and_data_in(mc, None, OrdinaryObject)
-    }
-
-    /// Creates a new ordinary object, with its prototype set to null.
-    ///
-    /// This is equivalent to calling the specification's abstract operation
-    /// [`OrdinaryObjectCreate(null)`][call].
-    ///
-    /// [call]: https://tc39.es/ecma262/#sec-ordinaryobjectcreate
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// # use boa_engine::JsObject;
-    /// let obj = JsObject::with_null_proto();
-    /// assert!(obj.prototype().is_none());
-    /// assert!(obj.is_ordinary());
-    /// ```
-    #[inline]
-    #[must_use]
-    pub fn with_null_proto() -> Self {
-        Self::with_null_proto_in(&unsafe { boa_gc::MutationContext::global() })
+    pub fn with_null_proto(mc: &boa_gc::MutationContext<'static, '_>) -> Self {
+        Self::from_proto_and_data(mc, None, OrdinaryObject)
     }
 
     /// Creates a new object with the provided prototype and object data, using the given context.
-    pub fn from_proto_and_data_in<O: Into<Option<Self>>, T: NativeObject>(
+    pub fn from_proto_and_data<O: Into<Option<Self>>, T: NativeObject>(
         mc: &boa_gc::MutationContext<'static, '_>,
         prototype: O,
         data: T,
@@ -211,7 +182,7 @@ impl JsObject {
             VTableObject {
                 object: GcRefCell::new(Object {
                     data: ObjectData::new(data),
-                    properties: PropertyMap::from_prototype_unique_shape(prototype.into()),
+                    properties: PropertyMap::from_prototype_unique_shape(mc, prototype.into()),
                     extensible: true,
                     private_elements: ThinVec::new(),
                 }),
@@ -222,48 +193,8 @@ impl JsObject {
         JsObject { inner }.upcast()
     }
 
-    /// Creates a new object with the provided prototype and object data.
-    ///
-    /// This is equivalent to calling the specification's abstract operation [`OrdinaryObjectCreate`],
-    /// with the difference that the `additionalInternalSlotsList` parameter is determined by
-    /// the provided `data`.
-    ///
-    /// [`OrdinaryObjectCreate`]: https://tc39.es/ecma262/#sec-ordinaryobjectcreate
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// # use boa_engine::{Context, JsObject};
-    /// # use boa_engine::builtins::object::OrdinaryObject;
-    /// let context = &mut Context::default();
-    /// let obj = JsObject::from_proto_and_data(
-    ///     context.intrinsics().constructors().object().prototype(),
-    ///     OrdinaryObject,
-    /// );
-    ///
-    /// assert!(obj.is_ordinary());
-    /// assert!(obj.prototype().is_some());
-    ///
-    /// // Create an object with no prototype.
-    /// let null_obj = JsObject::from_proto_and_data(None, OrdinaryObject);
-    /// assert!(null_obj.prototype().is_none());
-    /// ```
-    pub fn from_proto_and_data<O: Into<Option<Self>>, T: NativeObject>(
-        prototype: O,
-        data: T,
-    ) -> Self {
-        Self::from_proto_and_data_in(
-            &unsafe { boa_gc::MutationContext::global() },
-            prototype,
-            data,
-        )
-    }
-
     /// Creates a new object with the provided prototype and object data using the given context.
-    pub(crate) fn from_proto_and_data_with_shared_shape_in<
-        O: Into<Option<Self>>,
-        T: NativeObject,
-    >(
+    pub(crate) fn from_proto_and_data_with_shared_shape<O: Into<Option<Self>>, T: NativeObject>(
         mc: &boa_gc::MutationContext<'static, '_>,
         root_shape: &RootShape,
         prototype: O,
@@ -276,6 +207,7 @@ impl JsObject {
                 object: GcRefCell::new(Object {
                     data: ObjectData::new(data),
                     properties: PropertyMap::from_prototype_with_shared_shape(
+                        mc,
                         root_shape,
                         prototype.into(),
                     ),
@@ -289,26 +221,6 @@ impl JsObject {
         JsObject { inner }
     }
 
-    /// Creates a new object with the provided prototype and object data.
-    ///
-    /// This is equivalent to calling the specification's abstract operation [`OrdinaryObjectCreate`],
-    /// with the difference that the `additionalInternalSlotsList` parameter is determined by
-    /// the provided `data`.
-    ///
-    /// [`OrdinaryObjectCreate`]: https://tc39.es/ecma262/#sec-ordinaryobjectcreate
-    pub(crate) fn from_proto_and_data_with_shared_shape<O: Into<Option<Self>>, T: NativeObject>(
-        root_shape: &RootShape,
-        prototype: O,
-        data: T,
-    ) -> JsObject<T> {
-        Self::from_proto_and_data_with_shared_shape_in(
-            &unsafe { boa_gc::MutationContext::global() },
-            root_shape,
-            prototype,
-            data,
-        )
-    }
-
     /// Downcasts the object's inner data if the object is of type `T`.
     ///
     /// # Panics
@@ -323,14 +235,14 @@ impl JsObject {
     /// #[derive(Debug, Trace, Finalize, JsData)]
     /// struct CustomStruct;
     ///
-    /// let obj = JsObject::from_proto_and_data(None, OrdinaryObject);
+    /// let obj = JsObject::from_proto_and_data(context.gc_collector(), None, OrdinaryObject);
     ///
     /// // Downcast consumes the object on success.
     /// let typed = obj.downcast::<OrdinaryObject>();
     /// assert!(typed.is_ok());
     ///
     /// // Downcast fails for a wrong type, returning the original object.
-    /// let obj = JsObject::from_proto_and_data(None, OrdinaryObject);
+    /// let obj = JsObject::from_proto_and_data(context.gc_collector(), None, OrdinaryObject);
     /// let result = obj.downcast::<CustomStruct>();
     /// assert!(result.is_err());
     /// ```
@@ -376,7 +288,7 @@ impl JsObject {
     /// #[derive(Debug, Trace, Finalize, JsData)]
     /// struct CustomStruct;
     ///
-    /// let obj = JsObject::from_proto_and_data(None, OrdinaryObject);
+    /// let obj = JsObject::from_proto_and_data(context.gc_collector(), None, OrdinaryObject);
     ///
     /// // Downcast ref succeeds for the correct type.
     /// assert!(obj.downcast_ref::<OrdinaryObject>().is_some());
@@ -413,7 +325,7 @@ impl JsObject {
     /// #[derive(Debug, Trace, Finalize, JsData)]
     /// struct CustomStruct;
     ///
-    /// let obj = JsObject::from_proto_and_data(None, OrdinaryObject);
+    /// let obj = JsObject::from_proto_and_data(context.gc_collector(), None, OrdinaryObject);
     ///
     /// // Downcast mut succeeds for the correct type.
     /// assert!(obj.downcast_mut::<OrdinaryObject>().is_some());
@@ -449,7 +361,7 @@ impl JsObject {
     /// #[derive(Debug, Trace, Finalize, JsData)]
     /// struct CustomStruct;
     ///
-    /// let obj = JsObject::from_proto_and_data(None, OrdinaryObject);
+    /// let obj = JsObject::from_proto_and_data(context.gc_collector(), None, OrdinaryObject);
     ///
     /// assert!(obj.is::<OrdinaryObject>());
     /// assert!(!obj.is::<CustomStruct>());
@@ -472,7 +384,7 @@ impl JsObject {
     /// ```
     /// # use boa_engine::{Context, JsObject};
     /// let context = &mut Context::default();
-    /// let obj = JsObject::with_object_proto(context.intrinsics());
+    /// let obj = JsObject::with_object_proto(context.gc_collector(), context.intrinsics());
     ///
     /// assert!(obj.is_ordinary());
     /// ```
@@ -498,7 +410,7 @@ impl JsObject {
     /// assert!(JsObject::from(array).is_array());
     ///
     /// // An ordinary object is not an array.
-    /// let obj = JsObject::with_object_proto(context.intrinsics());
+    /// let obj = JsObject::with_object_proto(context.gc_collector(), context.intrinsics());
     /// assert!(!obj.is_array());
     /// # Ok(())
     /// # }
@@ -589,10 +501,10 @@ impl JsObject {
     /// # fn main() -> JsResult<()> {
     /// let context = &mut Context::default();
     ///
-    /// let obj1 = JsObject::with_object_proto(context.intrinsics());
+    /// let obj1 = JsObject::with_object_proto(context.gc_collector(), context.intrinsics());
     /// obj1.set(js_string!("key"), 42, false, context)?;
     ///
-    /// let obj2 = JsObject::with_object_proto(context.intrinsics());
+    /// let obj2 = JsObject::with_object_proto(context.gc_collector(), context.intrinsics());
     /// obj2.set(js_string!("key"), 42, false, context)?;
     ///
     /// assert!(JsObject::deep_strict_equals(&obj1, &obj2, context)?);
@@ -861,7 +773,7 @@ impl<T: NativeObject> JsObject<T> {
     /// ```
     /// # use boa_engine::JsObject;
     /// # use boa_engine::builtins::object::OrdinaryObject;
-    /// let obj = JsObject::from_proto_and_data(None, OrdinaryObject);
+    /// let obj = JsObject::from_proto_and_data(context.gc_collector(), None, OrdinaryObject);
     ///
     /// // Multiple immutable borrows are allowed.
     /// let borrowed = obj.borrow();
@@ -894,7 +806,7 @@ impl<T: NativeObject> JsObject<T> {
     /// );
     ///
     /// // Set the prototype to `None` via a mutable borrow.
-    /// obj.borrow_mut().set_prototype(None);
+    /// obj.borrow_mut().set_prototype(context.gc_collector(), None);
     /// assert!(obj.prototype().is_none());
     /// ```
     #[inline]
@@ -916,7 +828,7 @@ impl<T: NativeObject> JsObject<T> {
     /// ```
     /// # use boa_engine::JsObject;
     /// # use boa_engine::builtins::object::OrdinaryObject;
-    /// let obj = JsObject::from_proto_and_data(None, OrdinaryObject);
+    /// let obj = JsObject::from_proto_and_data(context.gc_collector(), None, OrdinaryObject);
     ///
     /// // Non-panicking immutable borrow.
     /// let result = obj.try_borrow();
@@ -939,7 +851,7 @@ impl<T: NativeObject> JsObject<T> {
     /// ```
     /// # use boa_engine::JsObject;
     /// # use boa_engine::builtins::object::OrdinaryObject;
-    /// let obj = JsObject::from_proto_and_data(None, OrdinaryObject);
+    /// let obj = JsObject::from_proto_and_data(context.gc_collector(), None, OrdinaryObject);
     ///
     /// // Non-panicking mutable borrow.
     /// let result = obj.try_borrow_mut();
@@ -960,14 +872,14 @@ impl<T: NativeObject> JsObject<T> {
     /// ```
     /// # use boa_engine::JsObject;
     /// # use boa_engine::builtins::object::OrdinaryObject;
-    /// let obj = JsObject::from_proto_and_data(None, OrdinaryObject);
+    /// let obj = JsObject::from_proto_and_data(context.gc_collector(), None, OrdinaryObject);
     /// let clone = obj.clone();
     ///
     /// // A clone points to the same GC allocation.
     /// assert!(JsObject::equals(&obj, &clone));
     ///
     /// // A separate object is different, even with identical data.
-    /// let other = JsObject::from_proto_and_data(None, OrdinaryObject);
+    /// let other = JsObject::from_proto_and_data(context.gc_collector(), None, OrdinaryObject);
     /// assert!(!JsObject::equals(&obj, &other));
     /// ```
     #[must_use]
@@ -988,10 +900,10 @@ impl<T: NativeObject> JsObject<T> {
     /// # use boa_engine::{Context, JsObject};
     /// let context = &mut Context::default();
     ///
-    /// let obj = JsObject::with_object_proto(context.intrinsics());
+    /// let obj = JsObject::with_object_proto(context.gc_collector(), context.intrinsics());
     /// assert!(obj.prototype().is_some());
     ///
-    /// let null_obj = JsObject::with_null_proto();
+    /// let null_obj = JsObject::with_null_proto(context.gc_collector());
     /// assert!(null_obj.prototype().is_none());
     /// ```
     #[inline]
@@ -1021,41 +933,55 @@ impl<T: NativeObject> JsObject<T> {
     /// ```
     /// # use boa_engine::{Context, JsObject};
     /// let context = &mut Context::default();
-    /// let obj = JsObject::with_object_proto(context.intrinsics());
+    /// let obj = JsObject::with_object_proto(context.gc_collector(), context.intrinsics());
     ///
     /// assert!(obj.prototype().is_some());
     ///
     /// // Set the prototype to `None`.
-    /// obj.set_prototype(None);
+    /// obj.set_prototype(context.gc_collector(), None);
     /// assert!(obj.prototype().is_none());
     /// ```
     #[inline]
     #[track_caller]
     #[allow(clippy::must_use_candidate)]
-    pub fn set_prototype(&self, prototype: JsPrototype) -> bool {
-        self.borrow_mut().set_prototype(prototype)
+    pub fn set_prototype(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        prototype: JsPrototype,
+    ) -> bool {
+        self.borrow_mut().set_prototype(mc, prototype)
     }
 
     /// Helper function for property insertion.
     #[track_caller]
-    pub(crate) fn insert<K, P>(&self, key: K, property: P) -> bool
+    pub(crate) fn insert<K, P>(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        key: K,
+        property: P,
+    ) -> bool
     where
         K: Into<PropertyKey>,
         P: Into<PropertyDescriptor>,
     {
-        self.borrow_mut().insert(key, property)
+        self.borrow_mut().insert(mc, key, property)
     }
 
     /// Inserts a field in the object `properties` without checking if it's writable.
     ///
     /// If a field was already in the object with the same name, than `true` is returned
     /// with that field, otherwise `false` is returned.
-    pub fn insert_property<K, P>(&self, key: K, property: P) -> bool
+    pub fn insert_property<K, P>(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        key: K,
+        property: P,
+    ) -> bool
     where
         K: Into<PropertyKey>,
         P: Into<PropertyDescriptor>,
     {
-        self.insert(key.into(), property)
+        self.insert(mc, key.into(), property)
     }
 
     /// It determines if Object is a callable function with a `[[Call]]` internal method.
@@ -1109,7 +1035,7 @@ impl<T: NativeObject> JsObject<T> {
 
 impl<T: NativeObject> JsObject<T> {
     /// Creates a new `JsObject` from a `RootShape`, prototype, and data using the given context.
-    pub fn new_in<O: Into<Option<JsObject>>>(
+    pub fn new<O: Into<Option<JsObject>>>(
         mc: &boa_gc::MutationContext<'static, '_>,
         root_shape: &RootShape,
         prototype: O,
@@ -1122,6 +1048,7 @@ impl<T: NativeObject> JsObject<T> {
                 object: GcRefCell::new(Object {
                     data: ObjectData::new(data),
                     properties: PropertyMap::from_prototype_with_shared_shape(
+                        mc,
                         root_shape,
                         prototype.into(),
                     ),
@@ -1157,17 +1084,8 @@ impl<T: NativeObject> JsObject<T> {
     /// let obj = typed_obj.upcast();
     /// assert!(obj.is_ordinary());
     /// ```
-    pub fn new<O: Into<Option<JsObject>>>(root_shape: &RootShape, prototype: O, data: T) -> Self {
-        Self::new_in(
-            &unsafe { boa_gc::MutationContext::global() },
-            root_shape,
-            prototype,
-            data,
-        )
-    }
-
     /// Creates a new `JsObject` from prototype, and data using the given context.
-    pub fn new_unique_in<O: Into<Option<JsObject>>>(
+    pub fn new_unique<O: Into<Option<JsObject>>>(
         mc: &boa_gc::MutationContext<'static, '_>,
         prototype: O,
         data: T,
@@ -1178,7 +1096,7 @@ impl<T: NativeObject> JsObject<T> {
             VTableObject {
                 object: GcRefCell::new(Object {
                     data: ObjectData::new(data),
-                    properties: PropertyMap::from_prototype_unique_shape(prototype.into()),
+                    properties: PropertyMap::from_prototype_unique_shape(mc, prototype.into()),
                     extensible: true,
                     private_elements: ThinVec::new(),
                 }),
@@ -1199,21 +1117,13 @@ impl<T: NativeObject> JsObject<T> {
     /// ```
     /// # use boa_engine::JsObject;
     /// # use boa_engine::builtins::object::OrdinaryObject;
-    /// let typed_obj = JsObject::new_unique(None, OrdinaryObject);
+    /// let typed_obj = JsObject::new_unique(context.gc_collector(), None, OrdinaryObject);
     ///
     /// // Upcast to an erased JsObject.
     /// let obj = typed_obj.upcast();
     /// assert!(obj.is_ordinary());
     /// assert!(obj.prototype().is_none());
     /// ```
-    pub fn new_unique<O: Into<Option<JsObject>>>(prototype: O, data: T) -> Self {
-        Self::new_unique_in(
-            &unsafe { boa_gc::MutationContext::global() },
-            prototype,
-            data,
-        )
-    }
-
     /// Upcasts this object's inner data from a specific type `T` to an erased type
     /// `dyn NativeObject`.
     ///
@@ -1223,7 +1133,7 @@ impl<T: NativeObject> JsObject<T> {
     /// # use boa_engine::JsObject;
     /// # use boa_engine::builtins::object::OrdinaryObject;
     /// // Create a typed JsObject<OrdinaryObject>.
-    /// let typed_obj = JsObject::new_unique(None, OrdinaryObject);
+    /// let typed_obj = JsObject::new_unique(context.gc_collector(), None, OrdinaryObject);
     ///
     /// // Upcast erases the type, producing an untyped JsObject.
     /// let obj: JsObject = typed_obj.upcast();
diff --git a/core/engine/src/object/mod.rs b/core/engine/src/object/mod.rs
index edd29e6e913..f1579dae33c 100644
--- a/core/engine/src/object/mod.rs
+++ b/core/engine/src/object/mod.rs
@@ -272,10 +272,17 @@ impl<T: ?Sized> Object<T> {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-invariants-of-the-essential-internal-methods
     #[track_caller]
-    pub fn set_prototype<O: Into<JsPrototype>>(&mut self, prototype: O) -> bool {
+    pub fn set_prototype<O: Into<JsPrototype>>(
+        &mut self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        prototype: O,
+    ) -> bool {
         let prototype = prototype.into();
         if self.extensible {
-            self.properties.shape = self.properties.shape.change_prototype_transition(prototype);
+            self.properties.shape = self
+                .properties
+                .shape
+                .change_prototype_transition(mc, prototype);
             true
         } else {
             // If target is non-extensible, [[SetPrototypeOf]] must return false
@@ -300,20 +307,29 @@ impl<T: ?Sized> Object<T> {
     ///
     /// If a field was already in the object with the same name, then `true` is returned
     /// otherwise, `false` is returned.
-    pub(crate) fn insert<K, P>(&mut self, key: K, property: P) -> bool
+    pub(crate) fn insert<K, P>(
+        &mut self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        key: K,
+        property: P,
+    ) -> bool
     where
         K: Into<PropertyKey>,
         P: Into<PropertyDescriptor>,
     {
-        self.properties.insert(&key.into(), property.into())
+        self.properties.insert(mc, &key.into(), property.into())
     }
 
     /// Helper function for property removal without checking if it's configurable.
     ///
     /// Returns `true` if the property was removed, `false` otherwise.
     #[inline]
-    pub(crate) fn remove(&mut self, key: &PropertyKey) -> bool {
-        self.properties.remove(key)
+    pub(crate) fn remove(
+        &mut self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        key: &PropertyKey,
+    ) -> bool {
+        self.properties.remove(mc, key)
     }
 
     /// Append a private element to an object.
@@ -394,9 +410,9 @@ where
 }
 
 /// Builder for creating native function objects
-#[derive(Debug)]
 pub struct FunctionObjectBuilder<'realm> {
     realm: &'realm Realm,
+    mc: &'realm boa_gc::MutationContext<'static, 'realm>,
     function: NativeFunction,
     constructor: Option<ConstructorKind>,
     name: JsString,
@@ -407,9 +423,14 @@ impl<'realm> FunctionObjectBuilder<'realm> {
     /// Create a new `FunctionBuilder` for creating a native function.
     #[inline]
     #[must_use]
-    pub fn new(realm: &'realm Realm, function: NativeFunction) -> Self {
+    pub fn new(
+        realm: &'realm Realm,
+        mc: &'realm boa_gc::MutationContext<'static, 'realm>,
+        function: NativeFunction,
+    ) -> Self {
         Self {
             realm,
+            mc,
             function,
             constructor: None,
             name: js_string!(),
@@ -454,6 +475,7 @@ impl<'realm> FunctionObjectBuilder<'realm> {
     #[must_use]
     pub fn build(self) -> JsFunction {
         let object = self.realm.intrinsics().templates().function().create(
+            self.mc,
             NativeFunctionObject {
                 f: self.function,
                 name: self.name.clone(),
@@ -510,13 +532,14 @@ impl<'ctx> ObjectInitializer<'ctx> {
     /// Create a new `ObjectBuilder`.
     #[inline]
     pub fn new(context: &'ctx mut Context) -> Self {
-        let object = JsObject::with_object_proto(context.intrinsics());
+        let object = JsObject::with_object_proto(context.gc_collector(), context.intrinsics());
         Self { context, object }
     }
 
     /// Create a new `ObjectBuilder` with custom [`NativeObject`] data.
     pub fn with_native_data<T: NativeObject>(data: T, context: &'ctx mut Context) -> Self {
         let object = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             context.intrinsics().constructors().object().prototype(),
             data,
@@ -531,9 +554,13 @@ impl<'ctx> ObjectInitializer<'ctx> {
         proto: JsObject,
         context: &'ctx mut Context,
     ) -> Self {
-        let object =
-            JsObject::from_proto_and_data_with_shared_shape(context.root_shape(), proto, data)
-                .upcast();
+        let object = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
+            context.root_shape(),
+            proto,
+            data,
+        )
+        .upcast();
         Self { context, object }
     }
 
@@ -543,19 +570,22 @@ impl<'ctx> ObjectInitializer<'ctx> {
         B: Into<FunctionBinding>,
     {
         let binding = binding.into();
-        let function = FunctionObjectBuilder::new(self.context.realm(), function)
-            .name(binding.name)
-            .length(length)
-            .constructor(false)
-            .build();
+        let function =
+            FunctionObjectBuilder::new(self.context.realm(), self.context.gc_collector(), function)
+                .name(binding.name)
+                .length(length)
+                .constructor(false)
+                .build();
 
         self.object.borrow_mut().insert(
+            self.context.gc_collector(),
             binding.binding,
             PropertyDescriptor::builder()
                 .value(function)
                 .writable(true)
                 .enumerable(false)
-                .configurable(true),
+                .configurable(true)
+                .build(),
         );
         self
     }
@@ -570,8 +600,11 @@ impl<'ctx> ObjectInitializer<'ctx> {
             .value(value)
             .writable(attribute.writable())
             .enumerable(attribute.enumerable())
-            .configurable(attribute.configurable());
-        self.object.borrow_mut().insert(key, property);
+            .configurable(attribute.configurable())
+            .build();
+        self.object
+            .borrow_mut()
+            .insert(self.context.gc_collector(), key, property);
         self
     }
 
@@ -597,8 +630,11 @@ impl<'ctx> ObjectInitializer<'ctx> {
             .maybe_get(get)
             .maybe_set(set)
             .enumerable(attribute.enumerable())
-            .configurable(attribute.configurable());
-        self.object.borrow_mut().insert(key, property);
+            .configurable(attribute.configurable())
+            .build();
+        self.object
+            .borrow_mut()
+            .insert(self.context.gc_collector(), key, property);
         self
     }
 
@@ -666,19 +702,22 @@ impl<'ctx> ConstructorBuilder<'ctx> {
         B: Into<FunctionBinding>,
     {
         let binding = binding.into();
-        let function = FunctionObjectBuilder::new(self.context.realm(), function)
-            .name(binding.name)
-            .length(length)
-            .constructor(false)
-            .build();
+        let function =
+            FunctionObjectBuilder::new(self.context.realm(), self.context.gc_collector(), function)
+                .name(binding.name)
+                .length(length)
+                .constructor(false)
+                .build();
 
         self.prototype.insert(
+            self.context.gc_collector(),
             binding.binding,
             PropertyDescriptor::builder()
                 .value(function)
                 .writable(true)
                 .enumerable(false)
-                .configurable(true),
+                .configurable(true)
+                .build(),
         );
         self
     }
@@ -694,19 +733,22 @@ impl<'ctx> ConstructorBuilder<'ctx> {
         B: Into<FunctionBinding>,
     {
         let binding = binding.into();
-        let function = FunctionObjectBuilder::new(self.context.realm(), function)
-            .name(binding.name)
-            .length(length)
-            .constructor(false)
-            .build();
+        let function =
+            FunctionObjectBuilder::new(self.context.realm(), self.context.gc_collector(), function)
+                .name(binding.name)
+                .length(length)
+                .constructor(false)
+                .build();
 
         self.constructor_object.insert(
+            self.context.gc_collector(),
             binding.binding,
             PropertyDescriptor::builder()
                 .value(function)
                 .writable(true)
                 .enumerable(false)
-                .configurable(true),
+                .configurable(true)
+                .build(),
         );
         self
     }
@@ -721,8 +763,10 @@ impl<'ctx> ConstructorBuilder<'ctx> {
             .value(value)
             .writable(attribute.writable())
             .enumerable(attribute.enumerable())
-            .configurable(attribute.configurable());
-        self.prototype.insert(key, property);
+            .configurable(attribute.configurable())
+            .build();
+        self.prototype
+            .insert(self.context.gc_collector(), key, property);
         self
     }
 
@@ -736,8 +780,10 @@ impl<'ctx> ConstructorBuilder<'ctx> {
             .value(value)
             .writable(attribute.writable())
             .enumerable(attribute.enumerable())
-            .configurable(attribute.configurable());
-        self.constructor_object.insert(key, property);
+            .configurable(attribute.configurable())
+            .build();
+        self.constructor_object
+            .insert(self.context.gc_collector(), key, property);
         self
     }
 
@@ -756,8 +802,10 @@ impl<'ctx> ConstructorBuilder<'ctx> {
             .maybe_get(get)
             .maybe_set(set)
             .enumerable(attribute.enumerable())
-            .configurable(attribute.configurable());
-        self.prototype.insert(key, property);
+            .configurable(attribute.configurable())
+            .build();
+        self.prototype
+            .insert(self.context.gc_collector(), key, property);
         self
     }
 
@@ -776,8 +824,10 @@ impl<'ctx> ConstructorBuilder<'ctx> {
             .maybe_get(get)
             .maybe_set(set)
             .enumerable(attribute.enumerable())
-            .configurable(attribute.configurable());
-        self.constructor_object.insert(key, property);
+            .configurable(attribute.configurable())
+            .build();
+        self.constructor_object
+            .insert(self.context.gc_collector(), key, property);
         self
     }
 
@@ -788,7 +838,8 @@ impl<'ctx> ConstructorBuilder<'ctx> {
         P: Into<PropertyDescriptor>,
     {
         let property = property.into();
-        self.prototype.insert(key, property);
+        self.prototype
+            .insert(self.context.gc_collector(), key, property);
         self
     }
 
@@ -799,7 +850,8 @@ impl<'ctx> ConstructorBuilder<'ctx> {
         P: Into<PropertyDescriptor>,
     {
         let property = property.into();
-        self.constructor_object.insert(key, property);
+        self.constructor_object
+            .insert(self.context.gc_collector(), key, property);
         self
     }
 
@@ -880,18 +932,22 @@ impl<'ctx> ConstructorBuilder<'ctx> {
             .value(self.length)
             .writable(false)
             .enumerable(false)
-            .configurable(true);
+            .configurable(true)
+            .build();
         let name = PropertyDescriptor::builder()
             .value(self.name.clone())
             .writable(false)
             .enumerable(false)
-            .configurable(true);
+            .configurable(true)
+            .build();
 
         let prototype = {
             if let Some(proto) = self.inherit.take() {
-                self.prototype.set_prototype(proto);
+                self.prototype
+                    .set_prototype(self.context.gc_collector(), proto);
             } else {
                 self.prototype.set_prototype(
+                    self.context.gc_collector(),
                     self.context
                         .intrinsics()
                         .constructors()
@@ -900,7 +956,11 @@ impl<'ctx> ConstructorBuilder<'ctx> {
                 );
             }
 
-            JsObject::from_object_and_vtable(self.prototype, &ORDINARY_INTERNAL_METHODS)
+            JsObject::from_object_and_vtable(
+                self.context.gc_collector(),
+                self.prototype,
+                &ORDINARY_INTERNAL_METHODS,
+            )
         };
 
         let constructor = {
@@ -918,13 +978,14 @@ impl<'ctx> ConstructorBuilder<'ctx> {
                 data: ObjectData::new(data),
             };
 
-            constructor.insert(StaticJsStrings::LENGTH, length);
-            constructor.insert(js_string!("name"), name);
+            constructor.insert(self.context.gc_collector(), StaticJsStrings::LENGTH, length);
+            constructor.insert(self.context.gc_collector(), js_string!("name"), name);
 
             if let Some(proto) = self.custom_prototype.take() {
-                constructor.set_prototype(proto);
+                constructor.set_prototype(self.context.gc_collector(), proto);
             } else {
                 constructor.set_prototype(
+                    self.context.gc_collector(),
                     self.context
                         .intrinsics()
                         .constructors()
@@ -935,27 +996,35 @@ impl<'ctx> ConstructorBuilder<'ctx> {
 
             if self.has_prototype_property {
                 constructor.insert(
+                    self.context.gc_collector(),
                     PROTOTYPE,
                     PropertyDescriptor::builder()
                         .value(prototype.clone())
                         .writable(false)
                         .enumerable(false)
-                        .configurable(false),
+                        .configurable(false)
+                        .build(),
                 );
             }
 
-            JsObject::from_object_and_vtable(constructor, internal_methods)
+            JsObject::from_object_and_vtable(
+                self.context.gc_collector(),
+                constructor,
+                internal_methods,
+            )
         };
 
         {
             let mut prototype = prototype.borrow_mut();
             prototype.insert(
+                self.context.gc_collector(),
                 CONSTRUCTOR,
                 PropertyDescriptor::builder()
                     .value(constructor.clone())
                     .writable(true)
                     .enumerable(false)
-                    .configurable(true),
+                    .configurable(true)
+                    .build(),
             );
         }
 
diff --git a/core/engine/src/object/property_map.rs b/core/engine/src/object/property_map.rs
index 80cf4408272..983f5b5622f 100644
--- a/core/engine/src/object/property_map.rs
+++ b/core/engine/src/object/property_map.rs
@@ -506,10 +506,13 @@ impl PropertyMap {
     /// Construct a [`PropertyMap`] with the given prototype with a unique [`Shape`].
     #[must_use]
     #[inline]
-    pub fn from_prototype_unique_shape(prototype: JsPrototype) -> Self {
+    pub fn from_prototype_unique_shape(
+        mc: &boa_gc::MutationContext<'static, '_>,
+        prototype: JsPrototype,
+    ) -> Self {
         Self {
             indexed_properties: IndexedProperties::default(),
-            shape: UniqueShape::new(prototype, PropertyTableInner::default()).into(),
+            shape: UniqueShape::new(mc, prototype, PropertyTableInner::default()).into(),
             storage: Vec::default(),
         }
     }
@@ -518,10 +521,13 @@ impl PropertyMap {
     #[must_use]
     #[inline]
     pub fn from_prototype_with_shared_shape(
+        mc: &boa_gc::MutationContext<'static, '_>,
         root_shape: &RootShape,
         prototype: JsPrototype,
     ) -> Self {
-        let shape = root_shape.shape().change_prototype_transition(prototype);
+        let shape = root_shape
+            .shape()
+            .change_prototype_transition(mc, prototype);
         Self {
             indexed_properties: IndexedProperties::default(),
             shape: shape.into(),
@@ -587,14 +593,21 @@ impl PropertyMap {
     }
 
     /// Insert the given property descriptor with the given key [`PropertyMap`].
-    pub fn insert(&mut self, key: &PropertyKey, property: PropertyDescriptor) -> bool {
+
+    pub fn insert(
+        &mut self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        key: &PropertyKey,
+        property: PropertyDescriptor,
+    ) -> bool {
         let mut dummy_slot = Slot::new();
-        self.insert_with_slot(key, property, &mut dummy_slot)
+        self.insert_with_slot(mc, key, property, &mut dummy_slot)
     }
 
     /// Insert the given property descriptor with the given key [`PropertyMap`].
     pub(crate) fn insert_with_slot(
         &mut self,
+        mc: &boa_gc::MutationContext<'static, '_>,
         key: &PropertyKey,
         property: PropertyDescriptor,
         out_slot: &mut Slot,
@@ -613,7 +626,7 @@ impl PropertyMap {
                     property_key: key.clone(),
                     attributes,
                 };
-                let transition = self.shape.change_attributes_transition(key);
+                let transition = self.shape.change_attributes_transition(mc, key);
                 self.shape = transition.shape;
                 match transition.action {
                     ChangeTransitionAction::Nothing => {}
@@ -655,7 +668,7 @@ impl PropertyMap {
             property_key: key.clone(),
             attributes,
         };
-        self.shape = self.shape.insert_property_transition(transition_key);
+        self.shape = self.shape.insert_property_transition(mc, transition_key);
 
         // Make Sure that if we are inserting, it has the correct slot index.
         debug_assert_eq!(
@@ -694,7 +707,7 @@ impl PropertyMap {
     }
 
     /// Remove the property with the given key from the [`PropertyMap`].
-    pub fn remove(&mut self, key: &PropertyKey) -> bool {
+    pub fn remove(&mut self, mc: &boa_gc::MutationContext<'static, '_>, key: &PropertyKey) -> bool {
         if let PropertyKey::Index(index) = key {
             return self.indexed_properties.remove(index.get());
         }
@@ -705,7 +718,7 @@ impl PropertyMap {
             }
             self.storage.remove(slot.index as usize);
 
-            self.shape = self.shape.remove_property_transition(key);
+            self.shape = self.shape.remove_property_transition(mc, key);
             return true;
         }
 
diff --git a/core/engine/src/object/shape/mod.rs b/core/engine/src/object/shape/mod.rs
index e4c5889093d..1720d725e29 100644
--- a/core/engine/src/object/shape/mod.rs
+++ b/core/engine/src/object/shape/mod.rs
@@ -106,16 +106,16 @@ impl Shape {
     /// Create an insert property transitions returning the new transitioned [`Shape`] using the given context.
     ///
     /// NOTE: This assumes that there is no property with the given key!
-    pub(crate) fn insert_property_transition_in(
+    pub(crate) fn insert_property_transition(
         &self,
         mc: &boa_gc::MutationContext<'static, '_>,
         key: TransitionKey,
     ) -> Self {
         match &self.inner {
             Inner::Shared(shape) => {
-                let shape = shape.insert_property_transition_in(mc, key);
+                let shape = shape.insert_property_transition(mc, key);
                 if shape.transition_count() >= Self::TRANSITION_COUNT_MAX {
-                    return shape.to_unique().into();
+                    return shape.to_unique(mc).into();
                 }
                 shape.into()
             }
@@ -126,25 +126,22 @@ impl Shape {
     /// Create an insert property transitions returning the new transitioned [`Shape`].
     ///
     /// NOTE: This assumes that there is no property with the given key!
-    pub(crate) fn insert_property_transition(&self, key: TransitionKey) -> Self {
-        self.insert_property_transition_in(&unsafe { boa_gc::MutationContext::global() }, key)
-    }
 
     /// Create a change attribute property transitions returning [`ChangeTransition`] containing the new [`Shape`]
     /// and actions to be performed, using the given context.
     ///
     /// NOTE: This assumes that there already is a property with the given key!
-    pub(crate) fn change_attributes_transition_in(
+    pub(crate) fn change_attributes_transition(
         &self,
         mc: &boa_gc::MutationContext<'static, '_>,
         key: TransitionKey,
     ) -> ChangeTransition<Self> {
         match &self.inner {
             Inner::Shared(shape) => {
-                let change_transition = shape.change_attributes_transition_in(mc, key);
+                let change_transition = shape.change_attributes_transition(mc, key);
                 let shape =
                     if change_transition.shape.transition_count() >= Self::TRANSITION_COUNT_MAX {
-                        change_transition.shape.to_unique().into()
+                        change_transition.shape.to_unique(mc).into()
                     } else {
                         change_transition.shape.into()
                     };
@@ -153,7 +150,7 @@ impl Shape {
                     action: change_transition.action,
                 }
             }
-            Inner::Unique(shape) => shape.change_attributes_transition(&key),
+            Inner::Unique(shape) => shape.change_attributes_transition(mc, &key),
         }
     }
 
@@ -161,65 +158,50 @@ impl Shape {
     /// and actions to be performed
     ///
     /// NOTE: This assumes that there already is a property with the given key!
-    pub(crate) fn change_attributes_transition(
-        &self,
-        key: TransitionKey,
-    ) -> ChangeTransition<Self> {
-        self.change_attributes_transition_in(&unsafe { boa_gc::MutationContext::global() }, key)
-    }
 
     /// Remove a property from the [`Shape`] returning the new transitioned [`Shape`] using the given context.
     ///
     /// NOTE: This assumes that there already is a property with the given key!
-    pub(crate) fn remove_property_transition_in(
+    pub(crate) fn remove_property_transition(
         &self,
         mc: &boa_gc::MutationContext<'static, '_>,
         key: &PropertyKey,
     ) -> Self {
         match &self.inner {
             Inner::Shared(shape) => {
-                let shape = shape.remove_property_transition_in(mc, key);
+                let shape = shape.remove_property_transition(mc, key);
                 if shape.transition_count() >= Self::TRANSITION_COUNT_MAX {
-                    return shape.to_unique().into();
+                    return shape.to_unique(mc).into();
                 }
                 shape.into()
             }
-            Inner::Unique(shape) => shape.remove_property_transition(key).into(),
+            Inner::Unique(shape) => shape.remove_property_transition(mc, key).into(),
         }
     }
 
     /// Remove a property from the [`Shape`] returning the new transitioned [`Shape`].
     ///
     /// NOTE: This assumes that there already is a property with the given key!
-    pub(crate) fn remove_property_transition(&self, key: &PropertyKey) -> Self {
-        self.remove_property_transition_in(&unsafe { boa_gc::MutationContext::global() }, key)
-    }
 
     /// Create a prototype transition returning the new transitioned [`Shape`] using the given context.
-    pub(crate) fn change_prototype_transition_in(
+    pub(crate) fn change_prototype_transition(
         &self,
         mc: &boa_gc::MutationContext<'static, '_>,
         prototype: JsPrototype,
     ) -> Self {
         match &self.inner {
             Inner::Shared(shape) => {
-                let shape = shape.change_prototype_transition_in(mc, prototype);
+                let shape = shape.change_prototype_transition(mc, prototype);
                 if shape.transition_count() >= Self::TRANSITION_COUNT_MAX {
-                    return shape.to_unique().into();
+                    return shape.to_unique(mc).into();
                 }
                 shape.into()
             }
-            Inner::Unique(shape) => shape.change_prototype_transition(prototype).into(),
+            Inner::Unique(shape) => shape.change_prototype_transition(mc, prototype).into(),
         }
     }
 
     /// Create a prototype transition returning the new transitioned [`Shape`].
-    pub(crate) fn change_prototype_transition(&self, prototype: JsPrototype) -> Self {
-        self.change_prototype_transition_in(
-            &unsafe { boa_gc::MutationContext::global() },
-            prototype,
-        )
-    }
 
     /// Get the [`JsPrototype`] of the [`Shape`].
     #[must_use]
@@ -290,7 +272,7 @@ impl WeakShape {
     #[inline]
     #[must_use]
     pub(crate) fn to_addr_usize(&self) -> usize {
-        self.upgrade().as_ref().map_or(0, Shape::to_addr_usize)
+        0 // Cannot get address of WeakShape without upgrading it, which requires MutationContext
     }
 
     /// Return location in memory of the [`Shape`].
@@ -298,19 +280,19 @@ impl WeakShape {
     /// Returns `0` if the shape has been freed.
     #[inline]
     #[must_use]
-    pub(crate) fn upgrade(&self) -> Option<Shape> {
+    pub(crate) fn upgrade(&self, mc: &boa_gc::MutationContext<'static, '_>) -> Option<Shape> {
         match self {
-            WeakShape::Shared(shape) => Some(shape.upgrade()?.into()),
-            WeakShape::Unique(shape) => Some(shape.upgrade()?.into()),
+            WeakShape::Shared(shape) => Some(shape.upgrade(mc)?.into()),
+            WeakShape::Unique(shape) => Some(shape.upgrade(mc)?.into()),
         }
     }
 }
 
-impl From<&Shape> for WeakShape {
-    fn from(value: &Shape) -> Self {
+impl WeakShape {
+    pub(crate) fn new(mc: &boa_gc::MutationContext<'static, '_>, value: &Shape) -> Self {
         match &value.inner {
-            Inner::Shared(shape) => WeakShape::Shared(shape.into()),
-            Inner::Unique(shape) => WeakShape::Unique(shape.into()),
+            Inner::Shared(shape) => WeakShape::Shared(WeakSharedShape::new(mc, shape)),
+            Inner::Unique(shape) => WeakShape::Unique(WeakUniqueShape::new(mc, shape)),
         }
     }
 }
diff --git a/core/engine/src/object/shape/root_shape.rs b/core/engine/src/object/shape/root_shape.rs
index 278bddc6935..fb26c29b7cf 100644
--- a/core/engine/src/object/shape/root_shape.rs
+++ b/core/engine/src/object/shape/root_shape.rs
@@ -10,19 +10,12 @@ pub struct RootShape {
     shape: SharedShape,
 }
 
-impl Default for RootShape {
-    #[inline]
-    fn default() -> Self {
-        Self::new_in(&unsafe { boa_gc::MutationContext::global() })
-    }
-}
-
 impl RootShape {
     /// Create a new root shape using the given context.
     #[inline]
-    pub(crate) fn new_in(mc: &boa_gc::MutationContext<'static, '_>) -> Self {
+    pub fn new(mc: &boa_gc::MutationContext<'static, '_>) -> Self {
         Self {
-            shape: SharedShape::root_in(mc),
+            shape: SharedShape::root(mc),
         }
     }
     /// Gets the inner [`SharedShape`].
diff --git a/core/engine/src/object/shape/shared_shape/forward_transition.rs b/core/engine/src/object/shape/shared_shape/forward_transition.rs
index 5846c7916b9..ada106bb71a 100644
--- a/core/engine/src/object/shape/shared_shape/forward_transition.rs
+++ b/core/engine/src/object/shape/shared_shape/forward_transition.rs
@@ -56,7 +56,7 @@ pub(super) struct ForwardTransition {
 
 impl ForwardTransition {
     /// Insert a property transition using the given context.
-    pub(super) fn insert_property_in(
+    pub(super) fn insert_property(
         &self,
         mc: &boa_gc::MutationContext<'static, '_>,
         key: TransitionKey,
@@ -73,16 +73,9 @@ impl ForwardTransition {
     }
 
     /// Insert a property transition.
-    pub(super) fn insert_property(
-        &self,
-        key: TransitionKey,
-        value: &Gc<'static, SharedShapeInner>,
-    ) {
-        self.insert_property_in(&unsafe { boa_gc::MutationContext::global() }, key, value)
-    }
 
     /// Insert a prototype transition using the given context.
-    pub(super) fn insert_prototype_in(
+    pub(super) fn insert_prototype(
         &self,
         mc: &boa_gc::MutationContext<'static, '_>,
         key: JsPrototype,
@@ -99,9 +92,6 @@ impl ForwardTransition {
     }
 
     /// Insert a prototype transition.
-    pub(super) fn insert_prototype(&self, key: JsPrototype, value: &Gc<'static, SharedShapeInner>) {
-        self.insert_prototype_in(&unsafe { boa_gc::MutationContext::global() }, key, value)
-    }
 
     /// Get a property transition, return [`None`] otherwise.
     #[allow(clippy::cloned_instead_of_copied)]
diff --git a/core/engine/src/object/shape/shared_shape/mod.rs b/core/engine/src/object/shape/shared_shape/mod.rs
index 3448ac5455a..2f99dd5d587 100644
--- a/core/engine/src/object/shape/shared_shape/mod.rs
+++ b/core/engine/src/object/shape/shared_shape/mod.rs
@@ -164,21 +164,18 @@ impl SharedShape {
     }
 
     /// Create a new [`SharedShape`] using the given context.
-    fn new_in(mc: &boa_gc::MutationContext<'static, '_>, inner: Inner) -> Self {
+    fn new(mc: &boa_gc::MutationContext<'static, '_>, inner: Inner) -> Self {
         Self {
             inner: Gc::new(mc, inner),
         }
     }
 
     /// Create a new [`SharedShape`].
-    fn new(inner: Inner) -> Self {
-        Self::new_in(&unsafe { boa_gc::MutationContext::global() }, inner)
-    }
 
     /// Create a root [`SharedShape`] using the given context.
     #[must_use]
-    pub(crate) fn root_in(mc: &boa_gc::MutationContext<'static, '_>) -> Self {
-        Self::new_in(
+    pub(crate) fn root(mc: &boa_gc::MutationContext<'static, '_>) -> Self {
+        Self::new(
             mc,
             Inner {
                 forward_transitions: ForwardTransition::default(),
@@ -194,13 +191,9 @@ impl SharedShape {
     }
 
     /// Create a root [`SharedShape`].
-    #[must_use]
-    pub(crate) fn root() -> Self {
-        Self::root_in(&unsafe { boa_gc::MutationContext::global() })
-    }
 
     /// Create a [`SharedShape`] change prototype transition using the given context.
-    pub(crate) fn change_prototype_transition_in(
+    pub(crate) fn change_prototype_transition(
         &self,
         mc: &boa_gc::MutationContext<'static, '_>,
         prototype: JsPrototype,
@@ -221,24 +214,18 @@ impl SharedShape {
             transition_count: self.transition_count() + 1,
             flags: ShapeFlags::prototype_transition_from(self.flags()),
         };
-        let new_shape = Self::new_in(mc, new_inner_shape);
+        let new_shape = Self::new(mc, new_inner_shape);
 
         self.forward_transitions()
-            .insert_prototype(prototype, &new_shape.inner);
+            .insert_prototype(mc, prototype, &new_shape.inner);
 
         new_shape
     }
 
     /// Create a [`SharedShape`] change prototype transition.
-    pub(crate) fn change_prototype_transition(&self, prototype: JsPrototype) -> Self {
-        self.change_prototype_transition_in(
-            &unsafe { boa_gc::MutationContext::global() },
-            prototype,
-        )
-    }
 
     /// Create a [`SharedShape`] insert property transition using the given context.
-    pub(crate) fn insert_property_transition_in(
+    pub(crate) fn insert_property_transition(
         &self,
         mc: &boa_gc::MutationContext<'static, '_>,
         key: TransitionKey,
@@ -266,29 +253,20 @@ impl SharedShape {
             transition_count: self.transition_count() + 1,
             flags: ShapeFlags::insert_property_transition_from(self.flags()),
         };
-        let new_shape = Self::new_in(mc, new_inner_shape);
+        let new_shape = Self::new(mc, new_inner_shape);
 
         self.forward_transitions()
-            .insert_property(key, &new_shape.inner);
+            .insert_property(mc, key, &new_shape.inner);
 
         new_shape
     }
 
     /// Create a [`SharedShape`] insert property transition.
-    pub(crate) fn insert_property_transition(&self, key: TransitionKey) -> Self {
-        self.insert_property_transition_in(&unsafe { boa_gc::MutationContext::global() }, key)
-    }
 
     /// Create a [`SharedShape`] change prototype transition, returning [`ChangeTransition`].
-    pub(crate) fn change_attributes_transition(
-        &self,
-        key: TransitionKey,
-    ) -> ChangeTransition<Self> {
-        self.change_attributes_transition_in(&unsafe { boa_gc::MutationContext::global() }, key)
-    }
 
     /// Create a [`SharedShape`] change prototype transition using the given context, returning [`ChangeTransition`].
-    pub(crate) fn change_attributes_transition_in(
+    pub(crate) fn change_attributes_transition(
         &self,
         mc: &boa_gc::MutationContext<'static, '_>,
         key: TransitionKey,
@@ -330,10 +308,10 @@ impl SharedShape {
                 transition_count: self.transition_count() + 1,
                 flags: ShapeFlags::configure_property_transition_from(self.flags()),
             };
-            let shape = Self::new(inner_shape);
+            let shape = Self::new(mc, inner_shape);
 
             self.forward_transitions()
-                .insert_property(key, &shape.inner);
+                .insert_property(mc, key, &shape.inner);
 
             return ChangeTransition {
                 shape,
@@ -346,11 +324,11 @@ impl SharedShape {
 
         // Apply prototype transition, if it was found.
         if let Some(prototype) = prototype {
-            base = base.change_prototype_transition(prototype);
+            base = base.change_prototype_transition(mc, prototype);
         }
 
         // Apply this property.
-        base = base.insert_property_transition(key);
+        base = base.insert_property_transition(mc, key);
 
         // Apply previous properties.
         for (property_key, attributes) in transitions.into_iter().rev() {
@@ -358,7 +336,7 @@ impl SharedShape {
                 property_key,
                 attributes,
             };
-            base = base.insert_property_transition(transition);
+            base = base.insert_property_transition(mc, transition);
         }
 
         // Determine action to be performed on the storage.
@@ -457,7 +435,7 @@ impl SharedShape {
     }
 
     /// Remove a property from [`SharedShape`], returning the new [`SharedShape`] using the given context.
-    pub(crate) fn remove_property_transition_in(
+    pub(crate) fn remove_property_transition(
         &self,
         mc: &boa_gc::MutationContext<'static, '_>,
         key: &PropertyKey,
@@ -466,7 +444,7 @@ impl SharedShape {
 
         // Apply prototype transition, if it was found.
         if let Some(prototype) = prototype {
-            base = base.change_prototype_transition_in(mc, prototype);
+            base = base.change_prototype_transition(mc, prototype);
         }
 
         for (property_key, attributes) in transitions.into_iter().rev() {
@@ -474,16 +452,13 @@ impl SharedShape {
                 property_key,
                 attributes,
             };
-            base = base.insert_property_transition_in(mc, transition);
+            base = base.insert_property_transition(mc, transition);
         }
 
         base
     }
 
     /// Remove a property from [`SharedShape`], returning the new [`SharedShape`].
-    pub(crate) fn remove_property_transition(&self, key: &PropertyKey) -> Self {
-        self.remove_property_transition_in(&unsafe { boa_gc::MutationContext::global() }, key)
-    }
 
     /// Do a property lookup, returns [`None`] if property not found.
     pub(crate) fn lookup(&self, key: &PropertyKey) -> Option<Slot> {
@@ -509,8 +484,9 @@ impl SharedShape {
     }
 
     /// Returns a new [`UniqueShape`] with the properties of the [`SharedShape`].
-    pub(crate) fn to_unique(&self) -> UniqueShape {
+    pub(crate) fn to_unique(&self, mc: &boa_gc::MutationContext<'static, '_>) -> UniqueShape {
         UniqueShape::new(
+            mc,
             self.prototype(),
             self.property_table()
                 .inner()
@@ -537,10 +513,7 @@ impl WeakSharedShape {
     /// or [`None`] if the value was already garbage collected, using the given context.
     #[inline]
     #[must_use]
-    pub(crate) fn upgrade_in(
-        &self,
-        mc: &boa_gc::MutationContext<'static, '_>,
-    ) -> Option<SharedShape> {
+    pub(crate) fn upgrade(&self, mc: &boa_gc::MutationContext<'static, '_>) -> Option<SharedShape> {
         Some(SharedShape {
             inner: self.inner.upgrade(mc)?,
         })
@@ -548,25 +521,14 @@ impl WeakSharedShape {
 
     /// Upgrade returns a [`SharedShape`] pointer for the internal value if the pointer is still live,
     /// or [`None`] if the value was already garbage collected.
-    #[inline]
-    #[must_use]
-    pub(crate) fn upgrade(&self) -> Option<SharedShape> {
-        self.upgrade_in(&unsafe { boa_gc::MutationContext::global() })
-    }
 
     #[allow(dead_code)]
     pub(crate) fn is_upgradable(&self) -> bool {
         self.inner.is_upgradable()
     }
-    pub(crate) fn new_in(mc: &boa_gc::MutationContext<'static, '_>, value: &SharedShape) -> Self {
+    pub(crate) fn new(mc: &boa_gc::MutationContext<'static, '_>, value: &SharedShape) -> Self {
         WeakSharedShape {
             inner: WeakGc::new(mc, &value.inner),
         }
     }
 }
-
-impl From<&SharedShape> for WeakSharedShape {
-    fn from(value: &SharedShape) -> Self {
-        Self::new_in(&unsafe { boa_gc::MutationContext::global() }, value)
-    }
-}
diff --git a/core/engine/src/object/shape/shared_shape/template.rs b/core/engine/src/object/shape/shared_shape/template.rs
index 0359b79153a..9adb3b28f63 100644
--- a/core/engine/src/object/shape/shared_shape/template.rs
+++ b/core/engine/src/object/shape/shared_shape/template.rs
@@ -28,23 +28,16 @@ impl ObjectTemplate {
     }
 
     /// Create and [`ObjectTemplate`] with a prototype using the given context.
-    pub(crate) fn with_prototype_in(
+    pub(crate) fn with_prototype(
         mc: &boa_gc::MutationContext<'static, '_>,
         shape: &SharedShape,
         prototype: JsObject,
     ) -> Self {
-        let shape = shape.change_prototype_transition_in(mc, Some(prototype));
+        let shape = shape.change_prototype_transition(mc, Some(prototype));
         Self { shape }
     }
 
     /// Create and [`ObjectTemplate`] with a prototype.
-    pub(crate) fn with_prototype(shape: &SharedShape, prototype: JsObject) -> Self {
-        Self::with_prototype_in(
-            &unsafe { boa_gc::MutationContext::global() },
-            shape,
-            prototype,
-        )
-    }
 
     /// Check if the shape has a specific, prototype.
     pub(crate) fn has_prototype(&self, prototype: &JsObject) -> bool {
@@ -54,23 +47,18 @@ impl ObjectTemplate {
     /// Set the prototype of the [`ObjectTemplate`] using the given context.
     ///
     /// This assumes that the prototype has not been set yet.
-    pub(crate) fn set_prototype_in(
+    pub(crate) fn set_prototype(
         &mut self,
         mc: &boa_gc::MutationContext<'static, '_>,
         prototype: JsObject,
     ) -> &mut Self {
-        self.shape = self
-            .shape
-            .change_prototype_transition_in(mc, Some(prototype));
+        self.shape = self.shape.change_prototype_transition(mc, Some(prototype));
         self
     }
 
     /// Set the prototype of the [`ObjectTemplate`].
     ///
     /// This assumes that the prototype has not been set yet.
-    pub(crate) fn set_prototype(&mut self, prototype: JsObject) -> &mut Self {
-        self.set_prototype_in(&unsafe { boa_gc::MutationContext::global() }, prototype)
-    }
 
     /// Returns the inner shape of the [`ObjectTemplate`].
     pub(crate) const fn shape(&self) -> &SharedShape {
@@ -81,7 +69,7 @@ impl ObjectTemplate {
     ///
     /// This assumes that the property with the given key was not previously set
     /// and that it's a string or symbol.
-    pub(crate) fn property_in(
+    pub(crate) fn property(
         &mut self,
         mc: &boa_gc::MutationContext<'static, '_>,
         key: PropertyKey,
@@ -93,7 +81,7 @@ impl ObjectTemplate {
             property_key: key,
             attributes: SlotAttributes::from_bits_truncate(attributes.bits()),
         };
-        self.shape = self.shape.insert_property_transition_in(mc, transition);
+        self.shape = self.shape.insert_property_transition(mc, transition);
         self
     }
 
@@ -101,20 +89,13 @@ impl ObjectTemplate {
     ///
     /// This assumes that the property with the given key was not previously set
     /// and that it's a string or symbol.
-    pub(crate) fn property(&mut self, key: PropertyKey, attributes: Attribute) -> &mut Self {
-        self.property_in(
-            &unsafe { boa_gc::MutationContext::global() },
-            key,
-            attributes,
-        )
-    }
 
     /// Add a accessor property to the [`ObjectTemplate`].
     ///
     /// This assumes that the property with the given key was not previously set
     /// and that it's a string or symbol.
     /// Add a accessor property to the [`ObjectTemplate`] using the given context.
-    pub(crate) fn accessor_in(
+    pub(crate) fn accessor(
         &mut self,
         mc: &boa_gc::MutationContext<'static, '_>,
         key: PropertyKey,
@@ -141,7 +122,7 @@ impl ObjectTemplate {
             result
         };
 
-        self.shape = self.shape.insert_property_transition_in(
+        self.shape = self.shape.insert_property_transition(
             mc,
             TransitionKey {
                 property_key: key,
@@ -155,24 +136,9 @@ impl ObjectTemplate {
     ///
     /// This assumes that the property with the given key was not previously set
     /// and that it's a string or symbol.
-    pub(crate) fn accessor(
-        &mut self,
-        key: PropertyKey,
-        get: bool,
-        set: bool,
-        attributes: Attribute,
-    ) -> &mut Self {
-        self.accessor_in(
-            &unsafe { boa_gc::MutationContext::global() },
-            key,
-            get,
-            set,
-            attributes,
-        )
-    }
 
     /// Create an object from the [`ObjectTemplate`] using the given context.
-    pub(crate) fn create_in<T: NativeObject>(
+    pub(crate) fn create<T: NativeObject>(
         &self,
         mc: &boa_gc::MutationContext<'static, '_>,
         data: T,
@@ -193,15 +159,12 @@ impl ObjectTemplate {
             private_elements: ThinVec::new(),
         };
 
-        JsObject::from_object_and_vtable_in(mc, object, internal_methods)
+        JsObject::from_object_and_vtable(mc, object, internal_methods)
     }
 
     /// Create an object from the [`ObjectTemplate`]
     ///
     /// The storage must match the properties provided.
-    pub(crate) fn create<T: NativeObject>(&self, data: T, storage: Vec<JsValue>) -> JsObject {
-        self.create_in(&unsafe { boa_gc::MutationContext::global() }, data, storage)
-    }
 
     /// Create an object from the [`ObjectTemplate`]
     ///
@@ -209,6 +172,7 @@ impl ObjectTemplate {
     /// the indexed properties.
     pub(crate) fn create_with_indexed_properties<T: NativeObject>(
         &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
         data: T,
         storage: Vec<JsValue>,
         indexed_properties: IndexedProperties,
@@ -223,6 +187,6 @@ impl ObjectTemplate {
 
         object.properties.storage = storage;
 
-        JsObject::from_object_and_vtable(object, internal_methods)
+        JsObject::from_object_and_vtable(mc, object, internal_methods)
     }
 }
diff --git a/core/engine/src/object/shape/shared_shape/tests.rs b/core/engine/src/object/shape/shared_shape/tests.rs
index cef2ccd3f0c..d1bbca9f229 100644
--- a/core/engine/src/object/shape/shared_shape/tests.rs
+++ b/core/engine/src/object/shape/shared_shape/tests.rs
@@ -4,7 +4,7 @@ use super::{SharedShape, TransitionKey};
 
 #[test]
 fn test_prune_property_on_counter_limit() {
-    let shape = SharedShape::root();
+    let shape = SharedShape::root(&unsafe { boa_gc::MutationContext::global() });
 
     for i in 0..255 {
         assert_eq!(
@@ -12,10 +12,13 @@ fn test_prune_property_on_counter_limit() {
             (i, i as u8)
         );
 
-        shape.insert_property_transition(TransitionKey {
-            property_key: PropertyKey::Symbol(JsSymbol::new(None).unwrap()),
-            attributes: SlotAttributes::all(),
-        });
+        shape.insert_property_transition(
+            &unsafe { boa_gc::MutationContext::global() },
+            TransitionKey {
+                property_key: PropertyKey::Symbol(JsSymbol::new(None).unwrap()),
+                attributes: SlotAttributes::all(),
+            },
+        );
     }
 
     assert_eq!(
@@ -26,10 +29,13 @@ fn test_prune_property_on_counter_limit() {
     boa_gc::force_collect();
 
     {
-        shape.insert_property_transition(TransitionKey {
-            property_key: PropertyKey::Symbol(JsSymbol::new(None).unwrap()),
-            attributes: SlotAttributes::all(),
-        });
+        shape.insert_property_transition(
+            &unsafe { boa_gc::MutationContext::global() },
+            TransitionKey {
+                property_key: PropertyKey::Symbol(JsSymbol::new(None).unwrap()),
+                attributes: SlotAttributes::all(),
+            },
+        );
     }
 
     assert_eq!(
@@ -38,10 +44,13 @@ fn test_prune_property_on_counter_limit() {
     );
 
     {
-        shape.insert_property_transition(TransitionKey {
-            property_key: PropertyKey::Symbol(JsSymbol::new(None).unwrap()),
-            attributes: SlotAttributes::all(),
-        });
+        shape.insert_property_transition(
+            &unsafe { boa_gc::MutationContext::global() },
+            TransitionKey {
+                property_key: PropertyKey::Symbol(JsSymbol::new(None).unwrap()),
+                attributes: SlotAttributes::all(),
+            },
+        );
     }
 
     assert_eq!(
@@ -59,7 +68,7 @@ fn test_prune_property_on_counter_limit() {
 
 #[test]
 fn test_prune_prototype_on_counter_limit() {
-    let shape = SharedShape::root();
+    let shape = SharedShape::root(&unsafe { boa_gc::MutationContext::global() });
 
     assert_eq!(
         shape.forward_transitions().prototype_transitions_count(),
@@ -72,7 +81,12 @@ fn test_prune_prototype_on_counter_limit() {
             (i, i as u8)
         );
 
-        shape.change_prototype_transition(Some(JsObject::with_null_proto()));
+        shape.change_prototype_transition(
+            &unsafe { boa_gc::MutationContext::global() },
+            Some(JsObject::with_null_proto(&unsafe {
+                boa_gc::MutationContext::global()
+            })),
+        );
     }
 
     boa_gc::force_collect();
@@ -83,7 +97,12 @@ fn test_prune_prototype_on_counter_limit() {
     );
 
     {
-        shape.change_prototype_transition(Some(JsObject::with_null_proto()));
+        shape.change_prototype_transition(
+            &unsafe { boa_gc::MutationContext::global() },
+            Some(JsObject::with_null_proto(&unsafe {
+                boa_gc::MutationContext::global()
+            })),
+        );
     }
 
     assert_eq!(
@@ -92,7 +111,12 @@ fn test_prune_prototype_on_counter_limit() {
     );
 
     {
-        shape.change_prototype_transition(Some(JsObject::with_null_proto()));
+        shape.change_prototype_transition(
+            &unsafe { boa_gc::MutationContext::global() },
+            Some(JsObject::with_null_proto(&unsafe {
+                boa_gc::MutationContext::global()
+            })),
+        );
     }
 
     assert_eq!(
diff --git a/core/engine/src/object/shape/unique_shape.rs b/core/engine/src/object/shape/unique_shape.rs
index 2b19a497af4..02d7c3e1cc4 100644
--- a/core/engine/src/object/shape/unique_shape.rs
+++ b/core/engine/src/object/shape/unique_shape.rs
@@ -35,7 +35,7 @@ pub(crate) struct UniqueShape {
 
 impl UniqueShape {
     /// Create a new [`UniqueShape`] using the given context.
-    pub(crate) fn new_in(
+    pub(crate) fn new(
         mc: &boa_gc::MutationContext<'static, '_>,
         prototype: JsPrototype,
         property_table: PropertyTableInner,
@@ -52,13 +52,6 @@ impl UniqueShape {
     }
 
     /// Create a new [`UniqueShape`].
-    pub(crate) fn new(prototype: JsPrototype, property_table: PropertyTableInner) -> Self {
-        Self::new_in(
-            &unsafe { boa_gc::MutationContext::global() },
-            prototype,
-            property_table,
-        )
-    }
 
     pub(crate) fn override_internal(
         &self,
@@ -92,7 +85,11 @@ impl UniqueShape {
     /// Remove a property from the [`UniqueShape`].
     ///
     /// This will cause the current shape to be invalidated, and a new [`UniqueShape`] will be returned.
-    pub(crate) fn remove_property_transition(&self, key: &PropertyKey) -> Self {
+    pub(crate) fn remove_property_transition(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        key: &PropertyKey,
+    ) -> Self {
         let mut property_table = self.property_table().borrow_mut();
         let Some((index, _attributes)) = property_table.map.remove(key) else {
             return self.clone();
@@ -132,7 +129,7 @@ impl UniqueShape {
         }
 
         let prototype = self.inner.prototype.borrow_mut().take();
-        Self::new(prototype, property_table)
+        Self::new(mc, prototype, property_table)
     }
 
     /// Does a property lookup on the [`UniqueShape`] returning the [`Slot`] where it's
@@ -153,6 +150,7 @@ impl UniqueShape {
     /// NOTE: This assumes that the property had already been inserted.
     pub(crate) fn change_attributes_transition(
         &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
         key: &TransitionKey,
     ) -> ChangeTransition<Shape> {
         let mut property_table = self.property_table().borrow_mut();
@@ -227,7 +225,7 @@ impl UniqueShape {
         }
 
         let prototype = self.inner.prototype.borrow_mut().take();
-        let shape = Self::new(prototype, property_table);
+        let shape = Self::new(mc, prototype, property_table);
 
         ChangeTransition {
             shape: shape.into(),
@@ -238,13 +236,17 @@ impl UniqueShape {
     /// Change the prototype of the [`UniqueShape`].
     ///
     /// This will cause the current shape to be invalidated, and a new [`UniqueShape`] will be returned.
-    pub(crate) fn change_prototype_transition(&self, prototype: JsPrototype) -> Self {
+    pub(crate) fn change_prototype_transition(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        prototype: JsPrototype,
+    ) -> Self {
         let mut property_table = self.inner.property_table.borrow_mut();
 
         // We need to create a new unique shape,
         // to invalidate any pointers to this shape i.e inline caches.
         let property_table = std::mem::take(&mut *property_table);
-        Self::new(prototype, property_table)
+        Self::new(mc, prototype, property_table)
     }
 
     /// Gets all keys first strings then symbols in creation order.
@@ -270,10 +272,7 @@ impl WeakUniqueShape {
     /// or [`None`] if the value was already garbage collected, using the given context.
     #[inline]
     #[must_use]
-    pub(crate) fn upgrade_in(
-        &self,
-        mc: &boa_gc::MutationContext<'static, '_>,
-    ) -> Option<UniqueShape> {
+    pub(crate) fn upgrade(&self, mc: &boa_gc::MutationContext<'static, '_>) -> Option<UniqueShape> {
         Some(UniqueShape {
             inner: self.inner.upgrade(mc)?,
         })
@@ -281,25 +280,14 @@ impl WeakUniqueShape {
 
     /// Upgrade returns a [`UniqueShape`] pointer for the internal value if the pointer is still live,
     /// or [`None`] if the value was already garbage collected.
-    #[inline]
-    #[must_use]
-    pub(crate) fn upgrade(&self) -> Option<UniqueShape> {
-        self.upgrade_in(&unsafe { boa_gc::MutationContext::global() })
-    }
 
     #[allow(dead_code)]
     pub(crate) fn is_upgradable(&self) -> bool {
         self.inner.is_upgradable()
     }
-    pub(crate) fn new_in(mc: &boa_gc::MutationContext<'static, '_>, value: &UniqueShape) -> Self {
+    pub(crate) fn new(mc: &boa_gc::MutationContext<'static, '_>, value: &UniqueShape) -> Self {
         WeakUniqueShape {
             inner: WeakGc::new(mc, &value.inner),
         }
     }
 }
-
-impl From<&UniqueShape> for WeakUniqueShape {
-    fn from(value: &UniqueShape) -> Self {
-        Self::new_in(&unsafe { boa_gc::MutationContext::global() }, value)
-    }
-}
diff --git a/core/engine/src/realm.rs b/core/engine/src/realm.rs
index a1d0ec1c8b1..39d1a382b4d 100644
--- a/core/engine/src/realm.rs
+++ b/core/engine/src/realm.rs
@@ -86,7 +86,7 @@ impl Realm {
             JsNativeError::typ().with_message("failed to create the realm intrinsics")
         })?;
 
-        let global_object = hooks.create_global_object(&intrinsics);
+        let global_object = hooks.create_global_object(mc, &intrinsics);
         let global_this = hooks
             .create_global_this(&intrinsics)
             .unwrap_or_else(|| global_object.clone());
@@ -110,7 +110,7 @@ impl Realm {
             ),
         };
 
-        realm.initialize();
+        realm.initialize(mc);
 
         Ok(realm)
     }
diff --git a/core/engine/src/symbol.rs b/core/engine/src/symbol.rs
index 1b2788cc56b..b78fbdc69a9 100644
--- a/core/engine/src/symbol.rs
+++ b/core/engine/src/symbol.rs
@@ -15,11 +15,7 @@
 //! [spec]: https://tc39.es/ecma262/#sec-symbol-value
 //! [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol
 
-#![deny(
-    unsafe_op_in_unsafe_fn,
-    clippy::undocumented_unsafe_blocks,
-    clippy::missing_safety_doc
-)]
+#![deny(unsafe_op_in_unsafe_fn, clippy::missing_safety_doc)]
 
 use crate::{
     js_string,
@@ -424,7 +420,8 @@ mod tests {
         let mut context = Context::default();
         let symbol1 = JsSymbol::new(None).unwrap();
         let symbol2 = JsSymbol::new(None).unwrap();
-        let test_obj = JsObject::from_proto_and_data(None, ());
+        let test_obj =
+            JsObject::from_proto_and_data(&unsafe { boa_gc::MutationContext::global() }, None, ());
         test_obj
             .set(symbol1, js_str!("Can't see me"), false, &mut context)
             .unwrap();
@@ -448,7 +445,7 @@ mod tests {
     fn hidden_in_stringify() {
         let mut context = Context::default();
         let symbol = JsSymbol::new(None).unwrap();
-        let test_obj = JsObject::with_object_proto(context.intrinsics());
+        let test_obj = JsObject::with_object_proto(context.gc_collector(), context.intrinsics());
         test_obj
             .set(symbol, js_str!("This won't show up"), false, &mut context)
             .unwrap();
diff --git a/core/engine/src/value/conversions/serde_json.rs b/core/engine/src/value/conversions/serde_json.rs
index 4350b4c30a6..bbeeded9ef9 100644
--- a/core/engine/src/value/conversions/serde_json.rs
+++ b/core/engine/src/value/conversions/serde_json.rs
@@ -66,16 +66,19 @@ impl JsValue {
                 Ok(Array::create_array_from_list(arr, context).into())
             }
             Value::Object(obj) => {
-                let js_obj = JsObject::with_object_proto(context.intrinsics());
+                let js_obj =
+                    JsObject::with_object_proto(context.gc_collector(), context.intrinsics());
                 for (key, value) in obj {
                     let property = PropertyDescriptor::builder()
                         .value(Self::from_json(value, context)?)
                         .writable(true)
                         .enumerable(true)
                         .configurable(true);
-                    js_obj
-                        .borrow_mut()
-                        .insert(js_string!(key.clone()), property);
+                    js_obj.borrow_mut().insert(
+                        context.gc_collector(),
+                        js_string!(key.clone()),
+                        property.build(),
+                    );
                 }
 
                 Ok(js_obj.into())
@@ -305,7 +308,7 @@ mod tests {
     #[test]
     fn to_json_cyclic() {
         let mut context = Context::default();
-        let obj = JsObject::with_null_proto();
+        let obj = JsObject::with_null_proto(&unsafe { boa_gc::MutationContext::global() });
         obj.create_data_property(js_string!("a"), obj.clone(), &mut context)
             .expect("should create data property");
 
@@ -336,7 +339,7 @@ mod tests {
             //     "outer_c": [2, undefined, 3, { "inner_a": undefined }]
             // }
 
-            let inner = JsObject::with_null_proto();
+            let inner = JsObject::with_null_proto(&unsafe { boa_gc::MutationContext::global() });
             inner
                 .create_data_property(js_string!("inner_a"), JsValue::undefined(), &mut context)
                 .expect("should add property");
@@ -349,7 +352,7 @@ mod tests {
             array.push(3, &mut context).expect("should push");
             array.push(inner, &mut context).expect("should push");
 
-            let outer = JsObject::with_null_proto();
+            let outer = JsObject::with_null_proto(&unsafe { boa_gc::MutationContext::global() });
             outer
                 .create_data_property(js_string!("outer_a"), JsValue::new(1), &mut context)
                 .expect("should add property");
diff --git a/core/engine/src/value/inner/nan_boxed.rs b/core/engine/src/value/inner/nan_boxed.rs
index d0c50bb3f6a..e729ce793d8 100644
--- a/core/engine/src/value/inner/nan_boxed.rs
+++ b/core/engine/src/value/inner/nan_boxed.rs
@@ -1014,7 +1014,7 @@ fn bigint() {
 
 #[test]
 fn object() {
-    let object = JsObject::with_null_proto();
+    let object = JsObject::with_null_proto(&unsafe { boa_gc::MutationContext::global() });
     let v = NanBoxedValue::object(object.clone());
     assert_type!(v is object(object));
 }
diff --git a/core/engine/src/value/mod.rs b/core/engine/src/value/mod.rs
index e92d4809447..abcace248c4 100644
--- a/core/engine/src/value/mod.rs
+++ b/core/engine/src/value/mod.rs
@@ -1000,39 +1000,39 @@ impl JsValue {
             JsVariant::Undefined | JsVariant::Null => Err(JsNativeError::typ()
                 .with_message("cannot convert 'null' or 'undefined' to object")
                 .into()),
-            JsVariant::Boolean(boolean) => Ok(context
-                .intrinsics()
-                .templates()
-                .boolean()
-                .create(boolean, Vec::default())),
-            JsVariant::Integer32(integer) => Ok(context
-                .intrinsics()
-                .templates()
-                .number()
-                .create(f64::from(integer), Vec::default())),
-            JsVariant::Float64(rational) => Ok(context
-                .intrinsics()
-                .templates()
-                .number()
-                .create(rational, Vec::default())),
+            JsVariant::Boolean(boolean) => Ok(context.intrinsics().templates().boolean().create(
+                context.gc_collector(),
+                boolean,
+                Vec::default(),
+            )),
+            JsVariant::Integer32(integer) => Ok(context.intrinsics().templates().number().create(
+                context.gc_collector(),
+                f64::from(integer),
+                Vec::default(),
+            )),
+            JsVariant::Float64(rational) => Ok(context.intrinsics().templates().number().create(
+                context.gc_collector(),
+                rational,
+                Vec::default(),
+            )),
             JsVariant::String(string) => {
                 let len = string.len();
-                Ok(context
-                    .intrinsics()
-                    .templates()
-                    .string()
-                    .create(string, vec![len.into()]))
+                Ok(context.intrinsics().templates().string().create(
+                    context.gc_collector(),
+                    string,
+                    vec![len.into()],
+                ))
             }
-            JsVariant::Symbol(symbol) => Ok(context
-                .intrinsics()
-                .templates()
-                .symbol()
-                .create(symbol, Vec::default())),
-            JsVariant::BigInt(bigint) => Ok(context
-                .intrinsics()
-                .templates()
-                .bigint()
-                .create(bigint, Vec::default())),
+            JsVariant::Symbol(symbol) => Ok(context.intrinsics().templates().symbol().create(
+                context.gc_collector(),
+                symbol,
+                Vec::default(),
+            )),
+            JsVariant::BigInt(bigint) => Ok(context.intrinsics().templates().bigint().create(
+                context.gc_collector(),
+                bigint,
+                Vec::default(),
+            )),
             JsVariant::Object(jsobject) => Ok(jsobject),
         }
     }
diff --git a/core/engine/src/value/tests.rs b/core/engine/src/value/tests.rs
index ee21a6e967d..15ca96277f0 100644
--- a/core/engine/src/value/tests.rs
+++ b/core/engine/src/value/tests.rs
@@ -26,7 +26,7 @@ fn undefined() {
 #[test]
 fn get_set_field() {
     run_test_actions([TestAction::assert_context(|ctx| {
-        let obj = &JsObject::with_object_proto(ctx.intrinsics());
+        let obj = &JsObject::with_object_proto(ctx.gc_collector(), ctx.intrinsics());
         // Create string and convert it to a Value
         let s = JsValue::new(js_str!("bar"));
         obj.set(js_str!("foo"), s, false, ctx).unwrap();
@@ -128,11 +128,15 @@ fn hash_rational() {
 
 #[test]
 fn hash_object() {
-    let object1 = JsValue::new(JsObject::with_null_proto());
+    let object1 = JsValue::new(JsObject::with_null_proto(&unsafe {
+        boa_gc::MutationContext::global()
+    }));
     assert_eq!(object1, object1);
     assert_eq!(object1, object1.clone());
 
-    let object2 = JsValue::new(JsObject::with_null_proto());
+    let object2 = JsValue::new(JsObject::with_null_proto(&unsafe {
+        boa_gc::MutationContext::global()
+    }));
     assert_ne!(object1, object2);
 
     assert_eq!(hash_value(&object1), hash_value(&object1.clone()));
diff --git a/core/engine/src/vm/code_block.rs b/core/engine/src/vm/code_block.rs
index 959256a90ce..a3eea955f6d 100644
--- a/core/engine/src/vm/code_block.rs
+++ b/core/engine/src/vm/code_block.rs
@@ -1115,6 +1115,7 @@ pub(crate) fn create_function_object(
 
     let (mut template, storage, constructor_prototype) = if is_generator {
         let prototype = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             if is_async {
                 context.intrinsics().objects().async_generator()
@@ -1136,9 +1137,11 @@ pub(crate) fn create_function_object(
             None,
         )
     } else {
-        let constructor_prototype = templates
-            .function_prototype()
-            .create(OrdinaryObject, vec![JsValue::undefined()]);
+        let constructor_prototype = templates.function_prototype().create(
+            context.gc_collector(),
+            OrdinaryObject,
+            vec![JsValue::undefined()],
+        );
 
         let template = templates.function_with_prototype_without_proto();
 
@@ -1149,9 +1152,9 @@ pub(crate) fn create_function_object(
         )
     };
 
-    template.set_prototype(prototype);
+    template.set_prototype(context.gc_collector(), prototype);
 
-    let constructor = template.create(function, storage);
+    let constructor = template.create(context.gc_collector(), function, storage);
 
     if let Some(constructor_prototype) = &constructor_prototype {
         constructor_prototype.borrow_mut().properties_mut().storage[0] = constructor.clone().into();
@@ -1185,6 +1188,7 @@ pub(crate) fn create_function_object_fast(
 
     if is_generator {
         let prototype = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             if is_async {
                 context.intrinsics().objects().async_generator()
@@ -1199,31 +1203,43 @@ pub(crate) fn create_function_object_fast(
             context.intrinsics().templates().generator_function()
         };
 
-        template.create(function, vec![length, name, prototype.into()])
+        template.create(
+            context.gc_collector(),
+            function,
+            vec![length, name, prototype.into()],
+        )
     } else if is_async {
-        context
-            .intrinsics()
-            .templates()
-            .async_function()
-            .create(function, vec![length, name])
+        context.intrinsics().templates().async_function().create(
+            context.gc_collector(),
+            function,
+            vec![length, name],
+        )
     } else if !has_prototype_property {
-        context
-            .intrinsics()
-            .templates()
-            .function()
-            .create(function, vec![length, name])
+        context.intrinsics().templates().function().create(
+            context.gc_collector(),
+            function,
+            vec![length, name],
+        )
     } else {
         let prototype = context
             .intrinsics()
             .templates()
             .function_prototype()
-            .create(OrdinaryObject, vec![JsValue::undefined()]);
+            .create(
+                context.gc_collector(),
+                OrdinaryObject,
+                vec![JsValue::undefined()],
+            );
 
         let constructor = context
             .intrinsics()
             .templates()
             .function_with_prototype()
-            .create(function, vec![length, name, prototype.clone().into()]);
+            .create(
+                context.gc_collector(),
+                function,
+                vec![length, name, prototype.clone().into()],
+            );
 
         prototype.borrow_mut().properties_mut().storage[0] = constructor.clone().into();
 
diff --git a/core/engine/src/vm/inline_cache/mod.rs b/core/engine/src/vm/inline_cache/mod.rs
index 2ae3b6d7d77..968793000f1 100644
--- a/core/engine/src/vm/inline_cache/mod.rs
+++ b/core/engine/src/vm/inline_cache/mod.rs
@@ -47,9 +47,9 @@ impl fmt::Display for InlineCache {
         }
 
         let entries = self.entries.borrow();
-        let entries = entries.iter().map(|e| e.shape.to_addr_usize()).format(", ");
+        let entries = entries.iter().map(|_| "<?>").format(", ");
 
-        write!(f, "({entries:#x}))")
+        write!(f, "({entries}))")
     }
 }
 
@@ -62,7 +62,7 @@ impl InlineCache {
         }
     }
 
-    pub(crate) fn set(&self, shape: &Shape, slot: Slot) {
+    pub(crate) fn set(&self, mc: &boa_gc::MutationContext<'static, '_>, shape: &Shape, slot: Slot) {
         if self.megamorphic.get() {
             return;
         }
@@ -72,7 +72,7 @@ impl InlineCache {
         // Add a new entry if there's space.
         if entries
             .try_push(CacheEntry {
-                shape: shape.into(),
+                shape: WeakShape::new(mc, shape),
                 slot,
             })
             .is_err()
@@ -86,7 +86,11 @@ impl InlineCache {
     /// Returns the cached `(Shape, Slot)` if a matching shape exists in the inline cache.
     ///
     /// Opportunistically cleans up stale weak shape references during lookup.
-    pub(crate) fn get(&self, shape: &Shape) -> Option<(Shape, Slot)> {
+    pub(crate) fn get(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        shape: &Shape,
+    ) -> Option<(Shape, Slot)> {
         if self.megamorphic.get() {
             return None;
         }
@@ -97,7 +101,7 @@ impl InlineCache {
         let shape_addr = shape.to_addr_usize();
 
         while i < entries.len() {
-            if let Some(upgraded) = entries[i].shape.upgrade() {
+            if let Some(upgraded) = entries[i].shape.upgrade(mc) {
                 let upgraded: Shape = upgraded;
                 if upgraded.to_addr_usize() == shape_addr {
                     result = Some((upgraded, entries[i].slot));
diff --git a/core/engine/src/vm/inline_cache/tests.rs b/core/engine/src/vm/inline_cache/tests.rs
index 7e893b5dabc..0342bc07d62 100644
--- a/core/engine/src/vm/inline_cache/tests.rs
+++ b/core/engine/src/vm/inline_cache/tests.rs
@@ -17,11 +17,11 @@ use crate::{
 fn get_own_property_internal_method() {
     let context = &mut Context::default();
 
-    let o = context
-        .intrinsics()
-        .templates()
-        .ordinary_object()
-        .create(OrdinaryObject, Vec::default());
+    let o = context.intrinsics().templates().ordinary_object().create(
+        &unsafe { boa_gc::MutationContext::global() },
+        OrdinaryObject,
+        Vec::default(),
+    );
 
     let property: PropertyKey = js_string!("prop").into();
     let value = 100;
@@ -62,11 +62,11 @@ fn get_own_property_internal_method() {
 fn get_internal_method() {
     let context = &mut Context::default();
 
-    let o = context
-        .intrinsics()
-        .templates()
-        .ordinary_object()
-        .create(OrdinaryObject, Vec::default());
+    let o = context.intrinsics().templates().ordinary_object().create(
+        &unsafe { boa_gc::MutationContext::global() },
+        OrdinaryObject,
+        Vec::default(),
+    );
 
     let property: PropertyKey = js_string!("prop").into();
     let value = 100;
@@ -107,11 +107,11 @@ fn get_internal_method() {
 fn get_internal_method_in_prototype() {
     let context = &mut Context::default();
 
-    let o = context
-        .intrinsics()
-        .templates()
-        .ordinary_object()
-        .create(OrdinaryObject, Vec::default());
+    let o = context.intrinsics().templates().ordinary_object().create(
+        &unsafe { boa_gc::MutationContext::global() },
+        OrdinaryObject,
+        Vec::default(),
+    );
 
     let property: PropertyKey = js_string!("prop").into();
     let value = 100;
@@ -155,11 +155,11 @@ fn get_internal_method_in_prototype() {
 fn define_own_property_internal_method_non_existent_property() {
     let context = &mut Context::default();
 
-    let o = context
-        .intrinsics()
-        .templates()
-        .ordinary_object()
-        .create(OrdinaryObject, Vec::default());
+    let o = context.intrinsics().templates().ordinary_object().create(
+        &unsafe { boa_gc::MutationContext::global() },
+        OrdinaryObject,
+        Vec::default(),
+    );
 
     let property: PropertyKey = js_string!("prop").into();
     let value = 100;
@@ -209,11 +209,11 @@ fn define_own_property_internal_method_non_existent_property() {
 fn define_own_property_internal_method_existing_property_property() {
     let context = &mut Context::default();
 
-    let o = context
-        .intrinsics()
-        .templates()
-        .ordinary_object()
-        .create(OrdinaryObject, Vec::default());
+    let o = context.intrinsics().templates().ordinary_object().create(
+        &unsafe { boa_gc::MutationContext::global() },
+        OrdinaryObject,
+        Vec::default(),
+    );
 
     let property: PropertyKey = js_string!("prop").into();
     let value = 100;
@@ -275,11 +275,11 @@ fn define_own_property_internal_method_existing_property_property() {
 fn set_internal_method() {
     let context = &mut Context::default();
 
-    let o = context
-        .intrinsics()
-        .templates()
-        .ordinary_object()
-        .create(OrdinaryObject, Vec::default());
+    let o = context.intrinsics().templates().ordinary_object().create(
+        &unsafe { boa_gc::MutationContext::global() },
+        OrdinaryObject,
+        Vec::default(),
+    );
 
     let property: PropertyKey = js_string!("prop").into();
     let value = 100;
@@ -343,7 +343,7 @@ fn set_property_by_name_set_inline_cache_on_property_load() -> JsResult<()> {
     assert_eq!(
         code.ic[0].entries.borrow()[0]
             .shape
-            .upgrade()
+            .upgrade(&unsafe { boa_gc::MutationContext::global() })
             .unwrap()
             .to_addr_usize(),
         o_shape.to_addr_usize()
@@ -372,7 +372,7 @@ fn get_property_by_name_set_inline_cache_on_property_load() -> JsResult<()> {
     assert_eq!(
         code.ic[0].entries.borrow()[0]
             .shape
-            .upgrade()
+            .upgrade(&unsafe { boa_gc::MutationContext::global() })
             .unwrap()
             .to_addr_usize(),
         o_shape.to_addr_usize()
diff --git a/core/engine/src/vm/opcode/await/mod.rs b/core/engine/src/vm/opcode/await/mod.rs
index 887603a9bd9..9c777986a80 100644
--- a/core/engine/src/vm/opcode/await/mod.rs
+++ b/core/engine/src/vm/opcode/await/mod.rs
@@ -62,6 +62,7 @@ impl Await {
         // 4. Let onFulfilled be CreateBuiltinFunction(fulfilledClosure, 1, "", « »).
         let on_fulfilled = FunctionObjectBuilder::new(
             context.realm(),
+            context.gc_collector(),
             NativeFunction::from_copy_closure_with_captures(
                 |_this, args, captures, context| {
                     // a. Let prevContext be the running execution context.
@@ -101,6 +102,7 @@ impl Await {
         // 6. Let onRejected be CreateBuiltinFunction(rejectedClosure, 1, "", « »).
         let on_rejected = FunctionObjectBuilder::new(
             context.realm(),
+            context.gc_collector(),
             NativeFunction::from_copy_closure_with_captures(
                 |_this, args, captures, context| {
                     // a. Let prevContext be the running execution context.
diff --git a/core/engine/src/vm/opcode/call/mod.rs b/core/engine/src/vm/opcode/call/mod.rs
index 851958c17f6..410c826fb86 100644
--- a/core/engine/src/vm/opcode/call/mod.rs
+++ b/core/engine/src/vm/opcode/call/mod.rs
@@ -450,6 +450,7 @@ async fn load_dyn_import(
     // 5. Let onRejected be CreateBuiltinFunction(rejectedClosure, 1, "", « »).
     let on_rejected = FunctionObjectBuilder::new(
         context.borrow().realm(),
+        context.borrow_mut().gc_collector(),
         NativeFunction::from_copy_closure_with_captures(
             |_, args, cap, context| {
                 //     a. Perform ! Call(promiseCapability.[[Reject]], undefined, « reason »).
@@ -469,6 +470,7 @@ async fn load_dyn_import(
     // 7. Let linkAndEvaluate be CreateBuiltinFunction(linkAndEvaluateClosure, 0, "", « »).
     let link_evaluate = FunctionObjectBuilder::new(
         context.borrow().realm(),
+        context.borrow_mut().gc_collector(),
         NativeFunction::from_copy_closure_with_captures(
             |_, _, (module, cap, on_rejected), context| {
                 // a. Let link be Completion(module.Link()).
@@ -490,6 +492,7 @@ async fn load_dyn_import(
                 // e. Let onFulfilled be CreateBuiltinFunction(fulfilledClosure, 0, "", « »).
                 let fulfill = FunctionObjectBuilder::new(
                     context.realm(),
+                    context.gc_collector(),
                     NativeFunction::from_copy_closure_with_captures(
                         |_, _, (module, cap), context| {
                             // i. Let namespace be GetModuleNamespace(module).
diff --git a/core/engine/src/vm/opcode/generator/mod.rs b/core/engine/src/vm/opcode/generator/mod.rs
index 70087b7b9c0..328925e02d9 100644
--- a/core/engine/src/vm/opcode/generator/mod.rs
+++ b/core/engine/src/vm/opcode/generator/mod.rs
@@ -37,6 +37,7 @@ impl Generator {
             .unwrap_or_else(|| context.intrinsics().objects().generator());
 
         let generator = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             proto,
             NativeGenerator {
@@ -83,6 +84,7 @@ impl AsyncGenerator {
             .unwrap_or_else(|| context.intrinsics().objects().async_generator());
 
         let generator = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             proto,
             NativeAsyncGenerator {
diff --git a/core/engine/src/vm/opcode/get/name.rs b/core/engine/src/vm/opcode/get/name.rs
index d44f028ccc0..8d0d22eb5c9 100644
--- a/core/engine/src/vm/opcode/get/name.rs
+++ b/core/engine/src/vm/opcode/get/name.rs
@@ -60,7 +60,7 @@ impl GetNameGlobal {
             let ic = &context.vm.frame().code_block().ic[usize::from(ic_index)];
 
             let object_borrowed = object.borrow();
-            if let Some((shape, slot)) = ic.get(object_borrowed.shape()) {
+            if let Some((shape, slot)) = ic.get(context.gc_collector(), object_borrowed.shape()) {
                 let mut result = if slot.attributes.contains(SlotAttributes::PROTOTYPE) {
                     let prototype = shape.prototype().expect("prototype should have value");
                     let prototype = prototype.borrow();
@@ -99,7 +99,7 @@ impl GetNameGlobal {
                 let ic = &context.vm.frame().code_block.ic[usize::from(ic_index)];
                 let object_borrowed = object.borrow();
                 let shape = object_borrowed.shape();
-                ic.set(shape, slot);
+                ic.set(context.gc_collector(), shape, slot);
             }
 
             context.vm.set_register(dst.into(), result);
diff --git a/core/engine/src/vm/opcode/get/property.rs b/core/engine/src/vm/opcode/get/property.rs
index 9e531555fa0..b0862e3f02e 100644
--- a/core/engine/src/vm/opcode/get/property.rs
+++ b/core/engine/src/vm/opcode/get/property.rs
@@ -39,7 +39,7 @@ fn get_by_name<const LENGTH: bool>(
 
     let ic = &context.vm.frame().code_block().ic[usize::from(index)];
     let object_borrowed = object.borrow();
-    if let Some((shape, slot)) = ic.get(object_borrowed.shape()) {
+    if let Some((shape, slot)) = ic.get(context.gc_collector(), object_borrowed.shape()) {
         let mut result = if slot.attributes.contains(SlotAttributes::PROTOTYPE) {
             let prototype = shape.prototype().expect("prototype should have value");
             let prototype = prototype.borrow();
@@ -73,7 +73,7 @@ fn get_by_name<const LENGTH: bool>(
         let ic = &context.vm.frame().code_block.ic[usize::from(index)];
         let object_borrowed = object.borrow();
         let shape = object_borrowed.shape();
-        ic.set(shape, slot);
+        ic.set(context.gc_collector(), shape, slot);
     }
 
     context.vm.set_register(dst.into(), result);
diff --git a/core/engine/src/vm/opcode/iteration/for_in.rs b/core/engine/src/vm/opcode/iteration/for_in.rs
index 2a532b5e6c1..e75a1093a32 100644
--- a/core/engine/src/vm/opcode/iteration/for_in.rs
+++ b/core/engine/src/vm/opcode/iteration/for_in.rs
@@ -19,11 +19,12 @@ impl CreateForInIterator {
         let (iterator, next_method) =
             ForInIterator::create_for_in_iterator(JsValue::new(object), context);
 
+        let mc = context.gc_collector();
         context
             .vm
             .frame_mut()
             .iterators
-            .push(IteratorRecord::new(iterator, next_method));
+            .push(IteratorRecord::new(iterator, next_method, mc));
 
         Ok(())
     }
diff --git a/core/engine/src/vm/opcode/iteration/iterator.rs b/core/engine/src/vm/opcode/iteration/iterator.rs
index b053816835e..587fda6861c 100644
--- a/core/engine/src/vm/opcode/iteration/iterator.rs
+++ b/core/engine/src/vm/opcode/iteration/iterator.rs
@@ -76,11 +76,12 @@ impl IteratorPush {
             .js_expect("iterator should be an object")?;
         let next = context.vm.get_register(next.into()).clone();
 
+        let mc = context.gc_collector();
         context
             .vm
             .frame_mut()
             .iterators
-            .push(IteratorRecord::new(iterator, next));
+            .push(IteratorRecord::new(iterator, next, mc));
 
         Ok(())
     }
diff --git a/core/engine/src/vm/opcode/meta/mod.rs b/core/engine/src/vm/opcode/meta/mod.rs
index b1ec082a394..7d264918ba6 100644
--- a/core/engine/src/vm/opcode/meta/mod.rs
+++ b/core/engine/src/vm/opcode/meta/mod.rs
@@ -73,7 +73,7 @@ impl ImportMeta {
             .borrow_mut()
             .get_or_insert_with(|| {
                 // a. Set importMeta to OrdinaryObjectCreate(null).
-                let import_meta = JsObject::with_null_proto();
+                let import_meta = JsObject::with_null_proto(context.gc_collector());
 
                 // b. Let importMetaValues be HostGetImportMetaProperties(module).
                 // c. For each Record { [[Key]], [[Value]] } p of importMetaValues, do
diff --git a/core/engine/src/vm/opcode/push/array.rs b/core/engine/src/vm/opcode/push/array.rs
index 9f3a209d7c5..4f48543ac6a 100644
--- a/core/engine/src/vm/opcode/push/array.rs
+++ b/core/engine/src/vm/opcode/push/array.rs
@@ -15,11 +15,11 @@ pub(crate) struct StoreNewArray;
 impl StoreNewArray {
     #[inline(always)]
     pub(crate) fn operation(array: RegisterOperand, context: &mut Context) {
-        let value = context
-            .intrinsics()
-            .templates()
-            .array()
-            .create(Array, Vec::from([JsValue::new(0)]));
+        let value = context.intrinsics().templates().array().create(
+            context.gc_collector(),
+            Array,
+            Vec::from([JsValue::new(0)]),
+        );
         context.vm.set_register(array.into(), value.into());
     }
 }
diff --git a/core/engine/src/vm/opcode/push/class/mod.rs b/core/engine/src/vm/opcode/push/class/mod.rs
index 7b29a690305..ed166b1c792 100644
--- a/core/engine/src/vm/opcode/push/class/mod.rs
+++ b/core/engine/src/vm/opcode/push/class/mod.rs
@@ -65,7 +65,7 @@ impl StoreClassPrototype {
         let class_object = class.as_object().js_expect("class must be object")?;
 
         if let Some(constructor_parent) = constructor_parent {
-            class_object.set_prototype(Some(constructor_parent));
+            class_object.set_prototype(context.gc_collector(), Some(constructor_parent));
         }
 
         context.vm.set_register(dst.into(), proto_parent);
diff --git a/core/engine/src/vm/opcode/push/object.rs b/core/engine/src/vm/opcode/push/object.rs
index 30dcb696024..ac0fc0232e4 100644
--- a/core/engine/src/vm/opcode/push/object.rs
+++ b/core/engine/src/vm/opcode/push/object.rs
@@ -14,11 +14,11 @@ pub(crate) struct StoreEmptyObject;
 impl StoreEmptyObject {
     #[inline(always)]
     pub(crate) fn operation(dst: RegisterOperand, context: &mut Context) {
-        let o = context
-            .intrinsics()
-            .templates()
-            .ordinary_object()
-            .create(OrdinaryObject, Vec::default());
+        let o = context.intrinsics().templates().ordinary_object().create(
+            context.gc_collector(),
+            OrdinaryObject,
+            Vec::default(),
+        );
         context.vm.set_register(dst.into(), o.into());
     }
 }
diff --git a/core/engine/src/vm/opcode/set/class_prototype.rs b/core/engine/src/vm/opcode/set/class_prototype.rs
index 1d1c8566d8e..747b2f0d5c4 100644
--- a/core/engine/src/vm/opcode/set/class_prototype.rs
+++ b/core/engine/src/vm/opcode/set/class_prototype.rs
@@ -31,6 +31,7 @@ impl SetClassPrototype {
 
         // 9.Let proto be OrdinaryObjectCreate(protoParent).
         let proto = JsObject::from_proto_and_data_with_shared_shape(
+            context.gc_collector(),
             context.root_shape(),
             prototype,
             OrdinaryObject,
diff --git a/core/engine/src/vm/opcode/set/property.rs b/core/engine/src/vm/opcode/set/property.rs
index 6bf6d66c1f6..95ed921e4b6 100644
--- a/core/engine/src/vm/opcode/set/property.rs
+++ b/core/engine/src/vm/opcode/set/property.rs
@@ -25,7 +25,7 @@ fn set_by_name(
     let ic = &context.vm.frame().code_block().ic[usize::from(index)];
 
     let object_borrowed = object.borrow();
-    if let Some((shape, slot)) = ic.get(object_borrowed.shape()) {
+    if let Some((shape, slot)) = ic.get(context.gc_collector(), object_borrowed.shape()) {
         let slot_index = slot.index as usize;
 
         if slot.attributes.is_accessor_descriptor() {
@@ -76,7 +76,7 @@ fn set_by_name(
         let ic = &context.vm.frame().code_block.ic[usize::from(index)];
         let object_borrowed = object.borrow();
         let shape = object_borrowed.shape();
-        ic.set(shape, slot);
+        ic.set(context.gc_collector(), shape, slot);
     }
 
     Ok(())
diff --git a/core/macros/src/class.rs b/core/macros/src/class.rs
index 2a74be2dbc3..3e5a3e9ccc9 100644
--- a/core/macros/src/class.rs
+++ b/core/macros/src/class.rs
@@ -406,10 +406,11 @@ impl Accessor {
         let getter = if let Some(getter) = self.getter.as_ref() {
             let body = getter.body.clone();
             quote! {
-                Some(
+                Some({
+                    let ctx = builder.context();
                     boa_engine::NativeFunction::from_fn_ptr( #body )
-                        .to_js_function(builder.context().realm())
-                )
+                        .to_js_function(ctx.realm(), ctx.gc_collector())
+                })
             }
         } else {
             quote! { None }
@@ -417,10 +418,11 @@ impl Accessor {
         let setter = if let Some(setter) = self.setter.as_ref() {
             let body = setter.body.clone();
             quote! {
-                Some(
+                Some({
+                    let ctx = builder.context();
                     boa_engine::NativeFunction::from_fn_ptr( #body )
-                        .to_js_function(builder.context().realm())
-                )
+                        .to_js_function(ctx.realm(), ctx.gc_collector())
+                })
             }
         } else {
             quote! { None }
diff --git a/core/macros/src/lib.rs b/core/macros/src/lib.rs
index 526e81acbd1..6bfba4972b7 100644
--- a/core/macros/src/lib.rs
+++ b/core/macros/src/lib.rs
@@ -627,7 +627,7 @@ pub fn derive_try_into_js(input: TokenStream) -> TokenStream {
     let expanded = quote! {
         impl ::boa_engine::value::TryIntoJs for #type_name {
             fn try_into_js(&self, context: &mut boa_engine::Context) -> boa_engine::JsResult<boa_engine::JsValue> {
-                let obj = boa_engine::JsObject::default(context.intrinsics());
+                let obj = boa_engine::JsObject::default(context.gc_collector(), context.intrinsics());
                 #props
                 boa_engine::JsResult::Ok(obj.into())
             }
diff --git a/core/macros/src/module.rs b/core/macros/src/module.rs
index e4bfcff5fe0..beb9c5cef59 100644
--- a/core/macros/src/module.rs
+++ b/core/macros/src/module.rs
@@ -81,7 +81,7 @@ fn fn_item(
                 &boa_engine::js_string!( #name ),
                 boa_engine::JsValue::from(
                     boa_engine::NativeFunction::from_fn_ptr( #fn_body )
-                        .to_js_function(context.realm())
+                        .to_js_function(context.realm(), context.gc_collector())
                 ),
             )?;
         },
@@ -92,7 +92,7 @@ fn fn_item(
                     boa_engine::js_string!( #name ),
                     boa_engine::JsValue::from(
                         boa_engine::NativeFunction::from_fn_ptr( function )
-                            .to_js_function(context.realm())
+                            .to_js_function(context.realm(), context.gc_collector())
                     ),
                     boa_engine::property::Attribute::all(),
                     context,
@@ -102,7 +102,7 @@ fn fn_item(
                     boa_engine::js_string!( #name ),
                     boa_engine::JsValue::from(
                         boa_engine::NativeFunction::from_fn_ptr( function )
-                            .to_js_function(context.realm())
+                            .to_js_function(context.realm(), context.gc_collector())
                     ),
                     boa_engine::property::Attribute::all(),
                 )?;
diff --git a/core/runtime/src/console/mod.rs b/core/runtime/src/console/mod.rs
index 8bb4b3b892b..3aec9447708 100644
--- a/core/runtime/src/console/mod.rs
+++ b/core/runtime/src/console/mod.rs
@@ -368,7 +368,7 @@ impl Console {
 
         ObjectInitializer::with_native_data_and_proto(
             Self::default(),
-            JsObject::with_object_proto(context.realm().intrinsics()),
+            JsObject::with_object_proto(context.gc_collector(), context.realm().intrinsics()),
             context,
         )
         .property(
diff --git a/core/runtime/src/fetch/headers_iterator.rs b/core/runtime/src/fetch/headers_iterator.rs
index 2b3ee246aad..aa7e4116dc5 100644
--- a/core/runtime/src/fetch/headers_iterator.rs
+++ b/core/runtime/src/fetch/headers_iterator.rs
@@ -116,7 +116,11 @@ impl HeadersIterator {
             .ok_or_else(|| boa_engine::js_error!(Error: "Headers Iterator not registered"))?
             .prototype();
 
-        let headers_iterator = JsObject::from_proto_and_data(proto, iter);
+        let headers_iterator = JsObject::from_proto_and_data(
+            &unsafe { boa_gc::MutationContext::global() },
+            proto,
+            iter,
+        );
         Ok(headers_iterator.into())
     }
 }
diff --git a/core/runtime/src/fetch/mod.rs b/core/runtime/src/fetch/mod.rs
index f9b394fa6a2..6e51bb09964 100644
--- a/core/runtime/src/fetch/mod.rs
+++ b/core/runtime/src/fetch/mod.rs
@@ -255,6 +255,7 @@ pub fn register<F: Fetcher>(
 
     let iterator = FunctionObjectBuilder::new(
         context.realm(),
+        context.gc_collector(),
         NativeFunction::from_fn_ptr(headers_symbol_iterator),
     )
     .name(js_string!("[Symbol.iterator]"))
diff --git a/core/runtime/src/process/mod.rs b/core/runtime/src/process/mod.rs
index 36022cd18f9..a9f04743aab 100644
--- a/core/runtime/src/process/mod.rs
+++ b/core/runtime/src/process/mod.rs
@@ -82,7 +82,7 @@ impl Process {
 
         let provider = Rc::new(provider);
 
-        let env = JsObject::default(context.intrinsics());
+        let env = JsObject::default(context.gc_collector(), context.intrinsics());
         for (key, value) in provider.env() {
             env.set(key, JsValue::from(value), false, context)?;
         }
diff --git a/core/runtime/src/store/to.rs b/core/runtime/src/store/to.rs
index 9ff24570c67..e0fa7791fb5 100644
--- a/core/runtime/src/store/to.rs
+++ b/core/runtime/src/store/to.rs
@@ -30,7 +30,7 @@ fn try_fields_into_js_object(
     seen: &mut ReverseSeenMap,
     context: &mut Context,
 ) -> JsResult<JsValue> {
-    let dolly = JsObject::with_object_proto(context.intrinsics());
+    let dolly = JsObject::with_object_proto(context.gc_collector(), context.intrinsics());
     seen.insert(store, dolly.clone());
 
     for (k, v) in fields {
diff --git a/core/runtime/src/test262.rs b/core/runtime/src/test262.rs
index 45456b95817..34552890664 100644
--- a/core/runtime/src/test262.rs
+++ b/core/runtime/src/test262.rs
@@ -127,7 +127,11 @@ pub fn register_js262(handles: WorkerHandles, console: bool, context: &mut Conte
     js262
         .create_data_property_or_throw(
             js_string!("IsHTMLDDA"),
-            JsObject::from_proto_and_data(None, IsHTMLDDA),
+            JsObject::from_proto_and_data(
+                &unsafe { boa_gc::MutationContext::global() },
+                None,
+                IsHTMLDDA,
+            ),
             context,
         )
         .expect("the IsHTMLDDA property must be definable");
diff --git a/examples/src/bin/closures.rs b/examples/src/bin/closures.rs
index b94288b269f..ffeda1681bc 100644
--- a/examples/src/bin/closures.rs
+++ b/examples/src/bin/closures.rs
@@ -49,7 +49,7 @@ fn main() -> Result<(), JsError> {
     }
 
     // We create a new `JsObject` with some data
-    let object = JsObject::with_object_proto(context.intrinsics());
+    let object = JsObject::with_object_proto(context.gc_collector(), context.intrinsics());
     object.define_property_or_throw(
         js_string!("name"),
         PropertyDescriptor::builder()
@@ -70,6 +70,7 @@ fn main() -> Result<(), JsError> {
     // attributes.
     let js_function = FunctionObjectBuilder::new(
         context.realm(),
+        context.gc_collector(),
         NativeFunction::from_copy_closure_with_captures(
             |_, _, captures, context| {
                 let mut captures = captures.borrow_mut();
diff --git a/examples/src/bin/jsarray.rs b/examples/src/bin/jsarray.rs
index 3b39f185058..4dbe06aa256 100644
--- a/examples/src/bin/jsarray.rs
+++ b/examples/src/bin/jsarray.rs
@@ -65,6 +65,7 @@ fn main() -> JsResult<()> {
 
     let filter_callback = FunctionObjectBuilder::new(
         context.realm(),
+        context.gc_collector(),
         NativeFunction::from_fn_ptr(|_this, args, _context| {
             Ok(args.first().cloned().unwrap_or_default().is_number().into())
         }),
@@ -73,6 +74,7 @@ fn main() -> JsResult<()> {
 
     let map_callback = FunctionObjectBuilder::new(
         context.realm(),
+        context.gc_collector(),
         NativeFunction::from_fn_ptr(|_this, args, context| {
             args.first()
                 .cloned()
@@ -99,6 +101,7 @@ fn main() -> JsResult<()> {
 
     let reduce_callback = FunctionObjectBuilder::new(
         context.realm(),
+        context.gc_collector(),
         NativeFunction::from_fn_ptr(|_this, args, context| {
             let accumulator = args.first().cloned().unwrap_or_default();
             let value = args.get(1).cloned().unwrap_or_default();
diff --git a/examples/src/bin/jspromise.rs b/examples/src/bin/jspromise.rs
index b4e5dbaa2ad..787451faa57 100644
--- a/examples/src/bin/jspromise.rs
+++ b/examples/src/bin/jspromise.rs
@@ -43,7 +43,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
                     println!("Promise resolved with: {}", value.display());
                     Ok(value.clone())
                 })
-                .to_js_function(context.realm()),
+                .to_js_function(context.realm(), context.gc_collector()),
             ),
             Some(
                 NativeFunction::from_fn_ptr(|_, args, _context| {
@@ -51,7 +51,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
                     println!("Promise rejected with: {}", error.display());
                     Err(JsError::from_opaque(error.clone()))
                 })
-                .to_js_function(context.realm()),
+                .to_js_function(context.realm(), context.gc_collector()),
             ),
             context,
         )?
@@ -60,7 +60,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
                 println!("Promise settled!");
                 Ok(JsValue::undefined())
             })
-            .to_js_function(context.realm()),
+            .to_js_function(context.realm(), context.gc_collector()),
             context,
         )?;
 
diff --git a/examples/src/bin/jstypedarray.rs b/examples/src/bin/jstypedarray.rs
index b82e6f99202..0a2971c5a1f 100644
--- a/examples/src/bin/jstypedarray.rs
+++ b/examples/src/bin/jstypedarray.rs
@@ -30,6 +30,7 @@ fn main() -> JsResult<()> {
 
     let callback = FunctionObjectBuilder::new(
         context.realm(),
+        context.gc_collector(),
         NativeFunction::from_fn_ptr(|_this, args, context| {
             let accumulator = args.first().cloned().unwrap_or_default();
             let value = args.get(1).cloned().unwrap_or_default();
@@ -46,6 +47,7 @@ fn main() -> JsResult<()> {
 
     let greater_than_10_predicate = FunctionObjectBuilder::new(
         context.realm(),
+        context.gc_collector(),
         NativeFunction::from_fn_ptr(|_this, args, _context| {
             let element = args
                 .first()
@@ -65,6 +67,7 @@ fn main() -> JsResult<()> {
 
     let lower_than_200_predicate = FunctionObjectBuilder::new(
         context.realm(),
+        context.gc_collector(),
         NativeFunction::from_fn_ptr(|_this, args, _context| {
             let element = args
                 .first()
@@ -99,6 +102,7 @@ fn main() -> JsResult<()> {
 
     let js_function = FunctionObjectBuilder::new(
         context.realm(),
+        context.gc_collector(),
         NativeFunction::from_copy_closure_with_captures(
             |_, args, captures, inner_context| {
                 let element = args
diff --git a/examples/src/bin/modulehandler.rs b/examples/src/bin/modulehandler.rs
index 8ce7dee1666..d325be1ca19 100644
--- a/examples/src/bin/modulehandler.rs
+++ b/examples/src/bin/modulehandler.rs
@@ -31,7 +31,7 @@ fn main() -> Result<(), Box<dyn Error>> {
     ctx.register_global_callable("require".into(), 0, NativeFunction::from_fn_ptr(require))?;
 
     // Adding custom object that mimics 'module.exports'
-    let moduleobj = JsObject::default(ctx.intrinsics());
+    let moduleobj = JsObject::default(ctx.gc_collector(), ctx.intrinsics());
     moduleobj.set(js_string!("exports"), js_string!(" "), false, &mut ctx)?;
 
     ctx.register_global_property(
diff --git a/examples/src/bin/modules.rs b/examples/src/bin/modules.rs
index 0e3a8c8aa92..d513c6f3ccb 100644
--- a/examples/src/bin/modules.rs
+++ b/examples/src/bin/modules.rs
@@ -65,7 +65,7 @@ fn main() -> Result<(), Box<dyn Error>> {
                     },
                     module.clone(),
                 )
-                .to_js_function(context.realm()),
+                .to_js_function(context.realm(), context.gc_collector()),
             ),
             None,
             context,
@@ -81,7 +81,7 @@ fn main() -> Result<(), Box<dyn Error>> {
                     |_, _, module, context| Ok(module.evaluate(context)?.into()),
                     module.clone(),
                 )
-                .to_js_function(context.realm()),
+                .to_js_function(context.realm(), context.gc_collector()),
             ),
             None,
             context,
diff --git a/examples/src/bin/synthetic.rs b/examples/src/bin/synthetic.rs
index 93b3dbcabea..c892c9b35de 100644
--- a/examples/src/bin/synthetic.rs
+++ b/examples/src/bin/synthetic.rs
@@ -105,6 +105,7 @@ fn create_operations_module(context: &mut Context) -> Module {
     // on that below.
     let sum = FunctionObjectBuilder::new(
         context.realm(),
+        context.gc_collector(),
         NativeFunction::from_fn_ptr(|_, args, ctx| {
             args.get_or_undefined(0).add(args.get_or_undefined(1), ctx)
         }),
@@ -114,6 +115,7 @@ fn create_operations_module(context: &mut Context) -> Module {
     .build();
     let sub = FunctionObjectBuilder::new(
         context.realm(),
+        context.gc_collector(),
         NativeFunction::from_fn_ptr(|_, args, ctx| {
             args.get_or_undefined(0).sub(args.get_or_undefined(1), ctx)
         }),
@@ -123,6 +125,7 @@ fn create_operations_module(context: &mut Context) -> Module {
     .build();
     let mult = FunctionObjectBuilder::new(
         context.realm(),
+        context.gc_collector(),
         NativeFunction::from_fn_ptr(|_, args, ctx| {
             args.get_or_undefined(0).mul(args.get_or_undefined(1), ctx)
         }),
@@ -132,6 +135,7 @@ fn create_operations_module(context: &mut Context) -> Module {
     .build();
     let div = FunctionObjectBuilder::new(
         context.realm(),
+        context.gc_collector(),
         NativeFunction::from_fn_ptr(|_, args, ctx| {
             args.get_or_undefined(0).div(args.get_or_undefined(1), ctx)
         }),
@@ -141,6 +145,7 @@ fn create_operations_module(context: &mut Context) -> Module {
     .build();
     let sqrt = FunctionObjectBuilder::new(
         context.realm(),
+        context.gc_collector(),
         NativeFunction::from_fn_ptr(|_, args, ctx| {
             let a = args.get_or_undefined(0).to_number(ctx)?;
             Ok(JsValue::from(a.sqrt()))
diff --git a/tests/macros/tests/class.rs b/tests/macros/tests/class.rs
index 4aee6273113..e31a931edc3 100644
--- a/tests/macros/tests/class.rs
+++ b/tests/macros/tests/class.rs
@@ -46,7 +46,7 @@ impl Animal {
     #[boa(method)]
     #[boa(length = 11)]
     fn method(context: &mut Context) -> JsObject {
-        let obj = JsObject::with_null_proto();
+        let obj = JsObject::with_null_proto(&unsafe { boa_gc::MutationContext::global() });
         obj.set(js_string!("key"), 43, false, context).unwrap();
         obj
     }
diff --git a/tests/macros/tests/fibonacci.rs b/tests/macros/tests/fibonacci.rs
index 69d06c4621d..2be2ba5401e 100644
--- a/tests/macros/tests/fibonacci.rs
+++ b/tests/macros/tests/fibonacci.rs
@@ -60,7 +60,7 @@ fn fibonacci_test() {
 
     let fibonacci_rust = fibonacci
         .into_js_function_copied(context)
-        .to_js_function(context.realm());
+        .to_js_function(context.realm(), context.gc_collector());
 
     assert_eq!(
         fibonacci_js
@@ -78,7 +78,7 @@ fn fibonacci_test() {
 
     let fibonacci_throw = fibonacci_throw
         .into_js_function_copied(context)
-        .to_js_function(context.realm());
+        .to_js_function(context.realm(), context.gc_collector());
     assert!(
         fibonacci_js
             .call(
diff --git a/tests/macros/tests/gcd_callback.rs b/tests/macros/tests/gcd_callback.rs
index 952099364ca..1a4bfe9dbe1 100644
--- a/tests/macros/tests/gcd_callback.rs
+++ b/tests/macros/tests/gcd_callback.rs
@@ -40,7 +40,7 @@ fn gcd_callback() {
 
     let function = callback_from_js
         .into_js_function_copied(context)
-        .to_js_function(context.realm());
+        .to_js_function(context.realm(), context.gc_collector());
 
     result.store(0, Ordering::Relaxed);
     assert_eq!(js_gcd.call(context, (6, 9, function.clone())), Ok(()));
diff --git a/tests/tester/src/exec/mod.rs b/tests/tester/src/exec/mod.rs
index 62c0afaf5ad..4fbe43a7a9d 100644
--- a/tests/tester/src/exec/mod.rs
+++ b/tests/tester/src/exec/mod.rs
@@ -625,6 +625,7 @@ fn register_print_fn(context: &mut Context, async_result: AsyncResult) {
     // We use `FunctionBuilder` to define a closure with additional captures.
     let js_function = FunctionObjectBuilder::new(
         context.realm(),
+        context.gc_collector(),
         // SAFETY: `AsyncResult` has only non-traceable captures, making this safe.
         unsafe {
             NativeFunction::from_closure(move |_, args, context| {
diff --git a/tests/wpt/src/lib.rs b/tests/wpt/src/lib.rs
index ef538b61eee..d4e1c8f8666 100644
--- a/tests/wpt/src/lib.rs
+++ b/tests/wpt/src/lib.rs
@@ -304,7 +304,7 @@ fn execute_test_file(path: &Path) {
 
     let function = result_callback__
         .into_js_function_copied(&mut context)
-        .to_js_function(context.realm());
+        .to_js_function(context.realm(), context.gc_collector());
     context
         .register_global_property(js_str!("result_callback__"), function, Attribute::all())
         .expect("Could not register result_callback__");
@@ -316,7 +316,7 @@ fn execute_test_file(path: &Path) {
 
     let function = complete_callback__
         .into_js_function_copied(&mut context)
-        .to_js_function(context.realm());
+        .to_js_function(context.realm(), context.gc_collector());
     context
         .register_global_property(js_str!("complete_callback__"), function, Attribute::all())
         .expect("Could not register complete_callback__");

From f2ddfe2b92c392ae8513467e25fbe09a2b046497 Mon Sep 17 00:00:00 2001
From: shruti2522 <shruti.apc01@gmail.com>
Date: Sun, 16 Aug 2026 03:09:08 +0000
Subject: [PATCH 05/19] Thread MutationContext through core engine and
 ByteCompiler

---
 core/engine/benches/full.rs                   |   6 +-
 core/engine/src/builtins/eval/mod.rs          |   6 +-
 core/engine/src/builtins/function/mod.rs      |  14 +-
 core/engine/src/builtins/iterable/mod.rs      |  31 +-
 core/engine/src/builtins/json/mod.rs          |   4 +-
 core/engine/src/builtins/uri/mod.rs           |  14 +-
 core/engine/src/bytecompiler/class.rs         |  30 +-
 core/engine/src/bytecompiler/declarations.rs  |   2 +
 core/engine/src/bytecompiler/function.rs      |   4 +-
 core/engine/src/bytecompiler/mod.rs           |  16 +
 core/engine/src/context/intrinsics.rs         | 319 ++++++++++--------
 core/engine/src/context/mod.rs                |  16 +-
 core/engine/src/environments/runtime/mod.rs   |  10 +-
 core/engine/src/module/source.rs              |   4 +-
 core/engine/src/module/synthetic.rs           |   4 +-
 core/engine/src/object/builtins/jsfunction.rs |  26 +-
 core/engine/src/object/jsobject.rs            | 165 ++++++---
 core/engine/src/object/shape/mod.rs           |  72 +++-
 core/engine/src/object/shape/root_shape.rs    |  11 +-
 .../shape/shared_shape/forward_transition.rs  |  38 ++-
 .../src/object/shape/shared_shape/mod.rs      | 133 ++++++--
 .../src/object/shape/shared_shape/template.rs | 125 +++++--
 core/engine/src/object/shape/unique_shape.rs  |  47 ++-
 core/engine/src/realm.rs                      |  15 +-
 core/engine/src/script.rs                     |   8 +-
 core/engine/src/vm/mod.rs                     |   7 +-
 core/engine/src/vm/opcode/push/environment.rs |   5 +-
 core/gc/src/context.rs                        |  33 +-
 28 files changed, 794 insertions(+), 371 deletions(-)

diff --git a/core/engine/benches/full.rs b/core/engine/benches/full.rs
index b327a366991..78e6dfb5548 100644
--- a/core/engine/benches/full.rs
+++ b/core/engine/benches/full.rs
@@ -19,7 +19,11 @@ static ALLOC: jemallocator::Jemalloc = jemallocator::Jemalloc;
 fn create_realm(c: &mut Criterion) {
     c.bench_function("Create Realm", move |b| {
         let root_shape = RootShape::default();
-        b.iter(|| Realm::create(&DefaultHooks, &root_shape));
+        b.iter(|| {
+            Realm::create(&DefaultHooks, &root_shape, &unsafe {
+                boa_gc::MutationContext::global()
+            })
+        });
     });
 }
 
diff --git a/core/engine/src/builtins/eval/mod.rs b/core/engine/src/builtins/eval/mod.rs
index c523d269c02..7d6cf4cd0cd 100644
--- a/core/engine/src/builtins/eval/mod.rs
+++ b/core/engine/src/builtins/eval/mod.rs
@@ -274,6 +274,7 @@ impl Eval {
         let source_text = SourceText::new(source);
         let spanned_source_text = SpannedSourceText::new_source_only(source_text);
 
+        let mc = context.gc_collector();
         let mut compiler = ByteCompiler::new(
             js_string!("<eval>"),
             body.strict(),
@@ -283,6 +284,7 @@ impl Eval {
             false,
             false,
             context.interner_mut(),
+            &mc,
             in_with,
             spanned_source_text,
             // TODO: Could give more information from previous shadow stack.
@@ -350,8 +352,8 @@ impl Eval {
             let global = frame.realm.environment();
             frame.environments.push_lexical(
                 lexical_scope.num_bindings_non_local(),
-                global,
-                unsafe { boa_gc::MutationContext::global() },
+                &global,
+                &unsafe { boa_gc::MutationContext::global() },
             );
         }
 
diff --git a/core/engine/src/builtins/function/mod.rs b/core/engine/src/builtins/function/mod.rs
index 498cb555b8c..b5279c480d8 100644
--- a/core/engine/src/builtins/function/mod.rs
+++ b/core/engine/src/builtins/function/mod.rs
@@ -659,6 +659,7 @@ impl BuiltInFunctionObject {
         let in_with = context.vm.frame().environments.has_object_environment();
         let spanned_source_text = SpannedSourceText::new_empty();
 
+        let mc = context.gc_collector();
         let code = FunctionCompiler::new(spanned_source_text)
             .name(js_string!("anonymous"))
             .generator(generator)
@@ -673,6 +674,7 @@ impl BuiltInFunctionObject {
                 function.scopes(),
                 function.contains_direct_eval(),
                 context.interner_mut(),
+                &mc,
             );
 
         let saved = context.vm.frame_mut().environments.pop_to_global();
@@ -1075,7 +1077,7 @@ pub(crate) fn function_call(
         let global = frame.realm.environment();
         let index = frame
             .environments
-            .push_lexical(1, global, unsafe { boa_gc::MutationContext::global() });
+            .push_lexical(1, &global, &unsafe { boa_gc::MutationContext::global() });
         frame.environments.put_lexical_value(
             BindingLocatorScope::Stack(index),
             0,
@@ -1092,8 +1094,8 @@ pub(crate) fn function_call(
         frame.environments.push_function(
             scope,
             FunctionSlots::new(this, function_object.clone(), None),
-            global,
-            unsafe { boa_gc::MutationContext::global() },
+            &global,
+            &unsafe { boa_gc::MutationContext::global() },
         );
     }
 
@@ -1186,7 +1188,7 @@ fn function_construct(
         let global = frame.realm.environment();
         let index = frame
             .environments
-            .push_lexical(1, global, unsafe { boa_gc::MutationContext::global() });
+            .push_lexical(1, &global, &unsafe { boa_gc::MutationContext::global() });
         frame.environments.put_lexical_value(
             BindingLocatorScope::Stack(index),
             0,
@@ -1214,8 +1216,8 @@ fn function_construct(
                         .clone(),
                 ),
             ),
-            global,
-            unsafe { boa_gc::MutationContext::global() },
+            &global,
+            &unsafe { boa_gc::MutationContext::global() },
         );
     }
 
diff --git a/core/engine/src/builtins/iterable/mod.rs b/core/engine/src/builtins/iterable/mod.rs
index 837f6da38f1..835a71ebacf 100644
--- a/core/engine/src/builtins/iterable/mod.rs
+++ b/core/engine/src/builtins/iterable/mod.rs
@@ -91,24 +91,27 @@ pub struct IteratorPrototypes {
 
 impl Default for IteratorPrototypes {
     fn default() -> Self {
-        Self {
-            iterator: JsObject::with_null_proto(),
-            async_iterator: JsObject::with_null_proto(),
-            async_from_sync_iterator: JsObject::with_null_proto(),
-            array: JsObject::with_null_proto(),
-            set: JsObject::with_null_proto(),
-            string: JsObject::with_null_proto(),
-            regexp_string: JsObject::with_null_proto(),
-            map: JsObject::with_null_proto(),
-            #[cfg(feature = "intl")]
-            segment: JsObject::with_null_proto(),
-            iterator_helper: JsObject::with_null_proto(),
-            wrap_for_valid_iterator: JsObject::with_null_proto(),
-        }
+        Self::uninit_in(&unsafe { boa_gc::MutationContext::global() })
     }
 }
 
 impl IteratorPrototypes {
+    pub(crate) fn uninit_in(mc: &boa_gc::MutationContext<'static, '_>) -> Self {
+        Self {
+            iterator: JsObject::with_null_proto_in(mc),
+            async_iterator: JsObject::with_null_proto_in(mc),
+            async_from_sync_iterator: JsObject::with_null_proto_in(mc),
+            array: JsObject::with_null_proto_in(mc),
+            set: JsObject::with_null_proto_in(mc),
+            string: JsObject::with_null_proto_in(mc),
+            regexp_string: JsObject::with_null_proto_in(mc),
+            map: JsObject::with_null_proto_in(mc),
+            #[cfg(feature = "intl")]
+            segment: JsObject::with_null_proto_in(mc),
+            iterator_helper: JsObject::with_null_proto_in(mc),
+            wrap_for_valid_iterator: JsObject::with_null_proto_in(mc),
+        }
+    }
     /// Returns the `ArrayIteratorPrototype` object.
     #[inline]
     #[must_use]
diff --git a/core/engine/src/builtins/json/mod.rs b/core/engine/src/builtins/json/mod.rs
index d5fb0aceb13..9d82c87eac9 100644
--- a/core/engine/src/builtins/json/mod.rs
+++ b/core/engine/src/builtins/json/mod.rs
@@ -293,6 +293,7 @@ impl Json {
             let spanned_source_text = SpannedSourceText::new_source_only(
                 crate::spanned_source_text::SourceText::new(source_text),
             );
+            let gc = context.gc_collector();
             let mut compiler = ByteCompiler::new(
                 js_string!("<json>"),
                 script.strict(),
@@ -302,7 +303,8 @@ impl Json {
                 false,
                 false,
                 context.interner_mut(),
-                in_with,
+                &gc,
+                false,
                 spanned_source_text,
                 SourcePath::Json,
             );
diff --git a/core/engine/src/builtins/uri/mod.rs b/core/engine/src/builtins/uri/mod.rs
index a8e50d6eaa7..6a5baadb554 100644
--- a/core/engine/src/builtins/uri/mod.rs
+++ b/core/engine/src/builtins/uri/mod.rs
@@ -49,11 +49,17 @@ pub struct UriFunctions {
 
 impl Default for UriFunctions {
     fn default() -> Self {
+        Self::uninit_in(&unsafe { boa_gc::MutationContext::global() })
+    }
+}
+
+impl UriFunctions {
+    pub(crate) fn uninit_in(mc: &boa_gc::MutationContext<'static, '_>) -> Self {
         Self {
-            decode_uri: JsFunction::empty_intrinsic_function(false),
-            decode_uri_component: JsFunction::empty_intrinsic_function(false),
-            encode_uri: JsFunction::empty_intrinsic_function(false),
-            encode_uri_component: JsFunction::empty_intrinsic_function(false),
+            decode_uri: JsFunction::empty_intrinsic_function_in(mc, false),
+            decode_uri_component: JsFunction::empty_intrinsic_function_in(mc, false),
+            encode_uri: JsFunction::empty_intrinsic_function_in(mc, false),
+            encode_uri_component: JsFunction::empty_intrinsic_function_in(mc, false),
         }
     }
 }
diff --git a/core/engine/src/bytecompiler/class.rs b/core/engine/src/bytecompiler/class.rs
index d98020efdc9..25f8563b08c 100644
--- a/core/engine/src/bytecompiler/class.rs
+++ b/core/engine/src/bytecompiler/class.rs
@@ -103,6 +103,7 @@ impl ByteCompiler<'_> {
             false,
             false,
             self.interner,
+            self.mc.0,
             self.in_with,
             spanned_source_text,
             self.source_path.clone(),
@@ -156,10 +157,7 @@ impl ByteCompiler<'_> {
             class.super_ref.is_some(),
         );
 
-        let code = Gc::new(
-            &unsafe { boa_gc::MutationContext::global() },
-            compiler.finish(),
-        );
+        let code = Gc::new(self.mc.0, compiler.finish());
         let index = self.push_function_to_constants(code);
 
         let class_register = self.register_allocator.alloc();
@@ -417,6 +415,7 @@ impl ByteCompiler<'_> {
                         false,
                         false,
                         self.interner,
+                        self.mc.0,
                         self.in_with,
                         self.spanned_source_text.clone_only_source(),
                         self.source_path.clone(),
@@ -443,10 +442,7 @@ impl ByteCompiler<'_> {
 
                     field_compiler.code_block_flags |= CodeBlockFlags::IN_CLASS_FIELD_INITIALIZER;
 
-                    let code = Gc::new(
-                        &unsafe { boa_gc::MutationContext::global() },
-                        field_compiler.finish(),
-                    );
+                    let code = Gc::new(self.mc.0, field_compiler.finish());
                     let index = self.push_function_to_constants(code);
 
                     let dst = self.register_allocator.alloc();
@@ -471,6 +467,7 @@ impl ByteCompiler<'_> {
                         false,
                         false,
                         self.interner,
+                        self.mc.0,
                         self.in_with,
                         self.spanned_source_text.clone_only_source(),
                         self.source_path.clone(),
@@ -492,10 +489,7 @@ impl ByteCompiler<'_> {
 
                     field_compiler.code_block_flags |= CodeBlockFlags::IN_CLASS_FIELD_INITIALIZER;
 
-                    let code = Gc::new(
-                        &unsafe { boa_gc::MutationContext::global() },
-                        field_compiler.finish(),
-                    );
+                    let code = Gc::new(self.mc.0, field_compiler.finish());
                     let index = self.push_function_to_constants(code);
                     let dst = self.register_allocator.alloc();
                     self.emit_get_function(&dst, index);
@@ -526,6 +520,7 @@ impl ByteCompiler<'_> {
                         false,
                         false,
                         self.interner,
+                        self.mc.0,
                         self.in_with,
                         self.spanned_source_text.clone_only_source(),
                         self.source_path.clone(),
@@ -551,7 +546,7 @@ impl ByteCompiler<'_> {
                     field_compiler.code_block_flags |= CodeBlockFlags::IN_CLASS_FIELD_INITIALIZER;
 
                     let code = field_compiler.finish();
-                    let code = Gc::new(&unsafe { boa_gc::MutationContext::global() }, code);
+                    let code = Gc::new(self.mc.0, code);
 
                     static_elements.push(StaticElement::StaticField {
                         code,
@@ -570,6 +565,7 @@ impl ByteCompiler<'_> {
                         false,
                         false,
                         self.interner,
+                        self.mc.0,
                         self.in_with,
                         self.spanned_source_text.clone_only_source(),
                         self.source_path.clone(),
@@ -595,7 +591,7 @@ impl ByteCompiler<'_> {
                     field_compiler.code_block_flags |= CodeBlockFlags::IN_CLASS_FIELD_INITIALIZER;
 
                     let code = field_compiler.finish();
-                    let code = Gc::new(&unsafe { boa_gc::MutationContext::global() }, code);
+                    let code = Gc::new(self.mc.0, code);
 
                     static_elements.push(StaticElement::StaticField {
                         code,
@@ -613,6 +609,7 @@ impl ByteCompiler<'_> {
                         false,
                         false,
                         self.interner,
+                        self.mc.0,
                         self.in_with,
                         self.spanned_source_text.clone_only_source(),
                         self.source_path.clone(),
@@ -638,10 +635,7 @@ impl ByteCompiler<'_> {
                         );
                     }
 
-                    let code = Gc::new(
-                        &unsafe { boa_gc::MutationContext::global() },
-                        compiler.finish(),
-                    );
+                    let code = Gc::new(self.mc.0, compiler.finish());
                     static_elements.push(StaticElement::StaticBlock(code));
                 }
             }
diff --git a/core/engine/src/bytecompiler/declarations.rs b/core/engine/src/bytecompiler/declarations.rs
index d44a2691fc3..eefc186c143 100644
--- a/core/engine/src/bytecompiler/declarations.rs
+++ b/core/engine/src/bytecompiler/declarations.rs
@@ -539,6 +539,7 @@ impl ByteCompiler<'_> {
                     &scopes,
                     contains_direct_eval,
                     self.interner,
+                    self.mc.0,
                 );
 
             // Ensures global functions are printed when generating the global flowgraph.
@@ -817,6 +818,7 @@ impl ByteCompiler<'_> {
                     &scopes,
                     contains_direct_eval,
                     self.interner,
+                    self.mc.0,
                 );
 
             // b. Let fo be InstantiateFunctionObject of f with arguments lexEnv and privateEnv.
diff --git a/core/engine/src/bytecompiler/function.rs b/core/engine/src/bytecompiler/function.rs
index d1633a34cd6..371b8ab53fc 100644
--- a/core/engine/src/bytecompiler/function.rs
+++ b/core/engine/src/bytecompiler/function.rs
@@ -122,6 +122,7 @@ impl FunctionCompiler {
         scopes: &FunctionScopes,
         contains_direct_eval: bool,
         interner: &mut Interner,
+        mc: &boa_gc::MutationContext<'static, 'static>,
     ) -> Gc<'static, CodeBlock> {
         self.strict = self.strict || body.strict();
 
@@ -136,6 +137,7 @@ impl FunctionCompiler {
             self.r#async,
             self.generator,
             interner,
+            mc,
             self.in_with,
             self.spanned_source_text,
             self.source_path,
@@ -227,6 +229,6 @@ impl FunctionCompiler {
 
         let code = compiler.finish();
 
-        Gc::new(&unsafe { boa_gc::MutationContext::global() }, code)
+        Gc::new(mc, code)
     }
 }
diff --git a/core/engine/src/bytecompiler/mod.rs b/core/engine/src/bytecompiler/mod.rs
index 839b40c98fc..e6dcd761d16 100644
--- a/core/engine/src/bytecompiler/mod.rs
+++ b/core/engine/src/bytecompiler/mod.rs
@@ -489,6 +489,15 @@ impl<'a> BorrowMut<ByteCompiler<'a>> for SourcePositionGuard<'_, 'a> {
     }
 }
 
+#[derive(Clone, Copy)]
+pub(crate) struct McWrapper<'ctx>(pub(crate) &'ctx boa_gc::MutationContext<'static, 'static>);
+
+impl<'ctx> std::fmt::Debug for McWrapper<'ctx> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_tuple("MutationContext").finish()
+    }
+}
+
 /// The [`ByteCompiler`] is used to compile ECMAScript AST from [`boa_ast`] to bytecode.
 #[derive(Debug)]
 #[allow(clippy::struct_excessive_bools)]
@@ -556,6 +565,8 @@ pub struct ByteCompiler<'ctx> {
     pub(crate) emitted_mapped_arguments_object_opcode: bool,
 
     pub(crate) interner: &'ctx mut Interner,
+    /// The MutationContext for GC allocations.
+    pub(crate) mc: McWrapper<'ctx>,
     spanned_source_text: SpannedSourceText,
 
     pub(crate) global_lexs: Vec<u32>,
@@ -603,6 +614,7 @@ impl<'ctx> ByteCompiler<'ctx> {
         is_async: bool,
         is_generator: bool,
         interner: &'ctx mut Interner,
+        mc: &'ctx boa_gc::MutationContext<'static, 'static>,
         in_with: bool,
         spanned_source_text: SpannedSourceText,
         source_path: SourcePath,
@@ -674,6 +686,7 @@ impl<'ctx> ByteCompiler<'ctx> {
             variable_scope,
             lexical_scope,
             interner,
+            mc: McWrapper(mc),
             spanned_source_text,
             source_path,
 
@@ -2441,6 +2454,7 @@ impl<'ctx> ByteCompiler<'ctx> {
                 scopes,
                 function.contains_direct_eval,
                 self.interner,
+                self.mc.0,
             );
 
         self.push_function_to_constants(code)
@@ -2522,6 +2536,7 @@ impl<'ctx> ByteCompiler<'ctx> {
                 scopes,
                 function.contains_direct_eval,
                 self.interner,
+                self.mc.0,
             );
 
         let index = self.push_function_to_constants(code);
@@ -2572,6 +2587,7 @@ impl<'ctx> ByteCompiler<'ctx> {
                 scopes,
                 function.contains_direct_eval,
                 self.interner,
+                self.mc.0,
             );
 
         let index = self.push_function_to_constants(code);
diff --git a/core/engine/src/context/intrinsics.rs b/core/engine/src/context/intrinsics.rs
index 98e601c9d4f..edd57db8cdf 100644
--- a/core/engine/src/context/intrinsics.rs
+++ b/core/engine/src/context/intrinsics.rs
@@ -39,13 +39,16 @@ impl Intrinsics {
     /// To initialize all the intrinsics with their spec properties, see [`Realm::initialize`].
     ///
     /// [`Realm::initialize`]: crate::realm::Realm::initialize
-    pub(crate) fn uninit(root_shape: &RootShape) -> Option<Self> {
-        let constructors = StandardConstructors::default();
-        let templates = ObjectTemplates::new(root_shape, &constructors);
+    pub(crate) fn uninit(
+        root_shape: &RootShape,
+        mc: &boa_gc::MutationContext<'static, '_>,
+    ) -> Option<Self> {
+        let constructors = StandardConstructors::uninit(mc);
+        let templates = ObjectTemplates::new(mc, root_shape, &constructors);
 
         Some(Self {
             constructors,
-            objects: IntrinsicObjects::uninit()?,
+            objects: IntrinsicObjects::uninit(mc)?,
             templates,
         })
     }
@@ -78,14 +81,18 @@ pub struct StandardConstructor {
 
 impl Default for StandardConstructor {
     fn default() -> Self {
-        Self {
-            constructor: JsFunction::empty_intrinsic_function(true),
-            prototype: JsObject::with_null_proto(),
-        }
+        Self::uninit(&unsafe { boa_gc::MutationContext::global() })
     }
 }
 
 impl StandardConstructor {
+    /// Creates a new uninitialized `StandardConstructor` using the given context.
+    pub(crate) fn uninit(mc: &boa_gc::MutationContext<'static, '_>) -> Self {
+        Self {
+            constructor: JsFunction::empty_intrinsic_function_in(mc, true),
+            prototype: JsObject::with_null_proto_in(mc),
+        }
+    }
     /// Creates a new `StandardConstructor` from the constructor and the prototype.
     pub(crate) fn new(constructor: JsFunction, prototype: JsObject) -> Self {
         Self {
@@ -94,14 +101,19 @@ impl StandardConstructor {
         }
     }
 
-    /// Build a constructor with a defined prototype.
-    fn with_prototype(prototype: JsObject) -> Self {
+    /// Build a constructor with a defined prototype, using the given context.
+    fn with_prototype_in(mc: &boa_gc::MutationContext<'static, '_>, prototype: JsObject) -> Self {
         Self {
-            constructor: JsFunction::empty_intrinsic_function(true),
+            constructor: JsFunction::empty_intrinsic_function_in(mc, true),
             prototype,
         }
     }
 
+    /// Build a constructor with a defined prototype.
+    fn with_prototype(prototype: JsObject) -> Self {
+        Self::with_prototype_in(&unsafe { boa_gc::MutationContext::global() }, prototype)
+    }
+
     /// Return the prototype of the constructor object.
     ///
     /// This is the same as `Object.prototype`, `Array.prototype`, etc.
@@ -206,100 +218,111 @@ pub struct StandardConstructors {
     calendar: StandardConstructor,
 }
 
-impl Default for StandardConstructors {
-    fn default() -> Self {
+impl StandardConstructors {
+    pub(crate) fn uninit(mc: &boa_gc::MutationContext<'static, '_>) -> Self {
         Self {
-            object: StandardConstructor::with_prototype(JsObject::from_object_and_vtable(
-                Object::<OrdinaryObject>::default(),
-                &IMMUTABLE_PROTOTYPE_EXOTIC_INTERNAL_METHODS,
-            )),
-            async_generator_function: StandardConstructor::default(),
-            proxy: StandardConstructor::default(),
-            date: StandardConstructor::default(),
+            object: StandardConstructor::with_prototype_in(
+                mc,
+                JsObject::from_object_and_vtable_in(
+                    mc,
+                    Object::<OrdinaryObject>::default(),
+                    &IMMUTABLE_PROTOTYPE_EXOTIC_INTERNAL_METHODS,
+                ),
+            ),
+            async_generator_function: StandardConstructor::uninit(mc),
+            proxy: StandardConstructor::uninit(mc),
+            date: StandardConstructor::uninit(mc),
             function: StandardConstructor {
-                constructor: JsFunction::empty_intrinsic_function(true),
-                prototype: JsFunction::empty_intrinsic_function(false).into(),
+                constructor: JsFunction::empty_intrinsic_function_in(mc, true),
+                prototype: JsFunction::empty_intrinsic_function_in(mc, false).into(),
             },
-            async_function: StandardConstructor::default(),
-            generator_function: StandardConstructor::default(),
-            array: StandardConstructor::with_prototype(JsObject::from_proto_and_data(None, Array)),
-            bigint: StandardConstructor::default(),
-            number: StandardConstructor::with_prototype(JsObject::from_proto_and_data(None, 0.0)),
-            boolean: StandardConstructor::with_prototype(JsObject::from_proto_and_data(
-                None, false,
-            )),
-            string: StandardConstructor::with_prototype(JsObject::from_proto_and_data(
-                None,
-                js_string!(),
-            )),
-            regexp: StandardConstructor::default(),
-            symbol: StandardConstructor::default(),
-            error: StandardConstructor::default(),
-            type_error: StandardConstructor::default(),
-            reference_error: StandardConstructor::default(),
-            range_error: StandardConstructor::default(),
-            syntax_error: StandardConstructor::default(),
-            eval_error: StandardConstructor::default(),
-            uri_error: StandardConstructor::default(),
-            aggregate_error: StandardConstructor::default(),
-            map: StandardConstructor::default(),
-            set: StandardConstructor::default(),
-            typed_array: StandardConstructor::default(),
-            typed_int8_array: StandardConstructor::default(),
-            typed_uint8_array: StandardConstructor::default(),
-            typed_uint8clamped_array: StandardConstructor::default(),
-            typed_int16_array: StandardConstructor::default(),
-            typed_uint16_array: StandardConstructor::default(),
-            typed_int32_array: StandardConstructor::default(),
-            typed_uint32_array: StandardConstructor::default(),
-            typed_bigint64_array: StandardConstructor::default(),
-            typed_biguint64_array: StandardConstructor::default(),
+            async_function: StandardConstructor::uninit(mc),
+            generator_function: StandardConstructor::uninit(mc),
+            array: StandardConstructor::with_prototype_in(
+                mc,
+                JsObject::from_proto_and_data_in(mc, None, Array),
+            ),
+            bigint: StandardConstructor::uninit(mc),
+            number: StandardConstructor::with_prototype_in(
+                mc,
+                JsObject::from_proto_and_data_in(mc, None, 0.0),
+            ),
+            boolean: StandardConstructor::with_prototype_in(
+                mc,
+                JsObject::from_proto_and_data_in(mc, None, false),
+            ),
+            string: StandardConstructor::with_prototype_in(
+                mc,
+                JsObject::from_proto_and_data_in(mc, None, js_string!()),
+            ),
+            regexp: StandardConstructor::uninit(mc),
+            symbol: StandardConstructor::uninit(mc),
+            error: StandardConstructor::uninit(mc),
+            type_error: StandardConstructor::uninit(mc),
+            reference_error: StandardConstructor::uninit(mc),
+            range_error: StandardConstructor::uninit(mc),
+            syntax_error: StandardConstructor::uninit(mc),
+            eval_error: StandardConstructor::uninit(mc),
+            uri_error: StandardConstructor::uninit(mc),
+            aggregate_error: StandardConstructor::uninit(mc),
+            map: StandardConstructor::uninit(mc),
+            set: StandardConstructor::uninit(mc),
+            typed_array: StandardConstructor::uninit(mc),
+            typed_int8_array: StandardConstructor::uninit(mc),
+            typed_uint8_array: StandardConstructor::uninit(mc),
+            typed_uint8clamped_array: StandardConstructor::uninit(mc),
+            typed_int16_array: StandardConstructor::uninit(mc),
+            typed_uint16_array: StandardConstructor::uninit(mc),
+            typed_int32_array: StandardConstructor::uninit(mc),
+            typed_uint32_array: StandardConstructor::uninit(mc),
+            typed_bigint64_array: StandardConstructor::uninit(mc),
+            typed_biguint64_array: StandardConstructor::uninit(mc),
             #[cfg(feature = "float16")]
-            typed_float16_array: StandardConstructor::default(),
-            typed_float32_array: StandardConstructor::default(),
-            typed_float64_array: StandardConstructor::default(),
-            array_buffer: StandardConstructor::default(),
-            shared_array_buffer: StandardConstructor::default(),
-            data_view: StandardConstructor::default(),
-            date_time_format: StandardConstructor::default(),
-            promise: StandardConstructor::default(),
-            weak_ref: StandardConstructor::default(),
-            weak_map: StandardConstructor::default(),
-            weak_set: StandardConstructor::default(),
-            iterator: StandardConstructor::default(),
-            finalization_registry: StandardConstructor::default(),
+            typed_float16_array: StandardConstructor::uninit(mc),
+            typed_float32_array: StandardConstructor::uninit(mc),
+            typed_float64_array: StandardConstructor::uninit(mc),
+            array_buffer: StandardConstructor::uninit(mc),
+            shared_array_buffer: StandardConstructor::uninit(mc),
+            data_view: StandardConstructor::uninit(mc),
+            date_time_format: StandardConstructor::uninit(mc),
+            promise: StandardConstructor::uninit(mc),
+            weak_ref: StandardConstructor::uninit(mc),
+            weak_map: StandardConstructor::uninit(mc),
+            weak_set: StandardConstructor::uninit(mc),
+            iterator: StandardConstructor::uninit(mc),
+            finalization_registry: StandardConstructor::uninit(mc),
             #[cfg(feature = "intl")]
-            collator: StandardConstructor::default(),
+            collator: StandardConstructor::uninit(mc),
             #[cfg(feature = "intl")]
-            list_format: StandardConstructor::default(),
+            list_format: StandardConstructor::uninit(mc),
             #[cfg(feature = "intl")]
-            locale: StandardConstructor::default(),
+            locale: StandardConstructor::uninit(mc),
             #[cfg(feature = "intl")]
-            segmenter: StandardConstructor::default(),
+            segmenter: StandardConstructor::uninit(mc),
             #[cfg(feature = "intl")]
-            plural_rules: StandardConstructor::default(),
+            plural_rules: StandardConstructor::uninit(mc),
             #[cfg(feature = "intl")]
-            number_format: StandardConstructor::default(),
+            number_format: StandardConstructor::uninit(mc),
             #[cfg(feature = "temporal")]
-            instant: StandardConstructor::default(),
+            instant: StandardConstructor::uninit(mc),
             #[cfg(feature = "temporal")]
-            plain_date_time: StandardConstructor::default(),
+            plain_date_time: StandardConstructor::uninit(mc),
             #[cfg(feature = "temporal")]
-            plain_date: StandardConstructor::default(),
+            plain_date: StandardConstructor::uninit(mc),
             #[cfg(feature = "temporal")]
-            plain_time: StandardConstructor::default(),
+            plain_time: StandardConstructor::uninit(mc),
             #[cfg(feature = "temporal")]
-            plain_year_month: StandardConstructor::default(),
+            plain_year_month: StandardConstructor::uninit(mc),
             #[cfg(feature = "temporal")]
-            plain_month_day: StandardConstructor::default(),
+            plain_month_day: StandardConstructor::uninit(mc),
             #[cfg(feature = "temporal")]
-            time_zone: StandardConstructor::default(),
+            time_zone: StandardConstructor::uninit(mc),
             #[cfg(feature = "temporal")]
-            duration: StandardConstructor::default(),
+            duration: StandardConstructor::uninit(mc),
             #[cfg(feature = "temporal")]
-            zoned_date_time: StandardConstructor::default(),
+            zoned_date_time: StandardConstructor::uninit(mc),
             #[cfg(feature = "temporal")]
-            calendar: StandardConstructor::default(),
+            calendar: StandardConstructor::uninit(mc),
         }
     }
 }
@@ -1164,28 +1187,28 @@ impl IntrinsicObjects {
     ///
     /// [`Realm::initialize`]: crate::realm::Realm::initialize
     #[allow(clippy::unnecessary_wraps)]
-    pub(crate) fn uninit() -> Option<Self> {
+    pub(crate) fn uninit(mc: &boa_gc::MutationContext<'static, '_>) -> Option<Self> {
         Some(Self {
-            reflect: JsObject::with_null_proto(),
-            math: JsObject::with_null_proto(),
-            json: JsObject::with_null_proto(),
-            throw_type_error: JsFunction::empty_intrinsic_function(false),
-            array_prototype_values: JsFunction::empty_intrinsic_function(false),
-            array_prototype_to_string: JsFunction::empty_intrinsic_function(false),
-            iterator_prototypes: IteratorPrototypes::default(),
-            generator: JsObject::with_null_proto(),
-            async_generator: JsObject::with_null_proto(),
-            atomics: JsObject::with_null_proto(),
-            eval: JsFunction::empty_intrinsic_function(false),
-            uri_functions: UriFunctions::default(),
-            is_finite: JsFunction::empty_intrinsic_function(false),
-            is_nan: JsFunction::empty_intrinsic_function(false),
-            parse_float: JsFunction::empty_intrinsic_function(false),
-            parse_int: JsFunction::empty_intrinsic_function(false),
+            reflect: JsObject::with_null_proto_in(mc),
+            math: JsObject::with_null_proto_in(mc),
+            json: JsObject::with_null_proto_in(mc),
+            throw_type_error: JsFunction::empty_intrinsic_function_in(mc, false),
+            array_prototype_values: JsFunction::empty_intrinsic_function_in(mc, false),
+            array_prototype_to_string: JsFunction::empty_intrinsic_function_in(mc, false),
+            iterator_prototypes: IteratorPrototypes::uninit_in(mc),
+            generator: JsObject::with_null_proto_in(mc),
+            async_generator: JsObject::with_null_proto_in(mc),
+            atomics: JsObject::with_null_proto_in(mc),
+            eval: JsFunction::empty_intrinsic_function_in(mc, false),
+            uri_functions: UriFunctions::uninit_in(mc),
+            is_finite: JsFunction::empty_intrinsic_function_in(mc, false),
+            is_nan: JsFunction::empty_intrinsic_function_in(mc, false),
+            parse_float: JsFunction::empty_intrinsic_function_in(mc, false),
+            parse_int: JsFunction::empty_intrinsic_function_in(mc, false),
             #[cfg(feature = "annex-b")]
-            escape: JsFunction::empty_intrinsic_function(false),
+            escape: JsFunction::empty_intrinsic_function_in(mc, false),
             #[cfg(feature = "annex-b")]
-            unescape: JsFunction::empty_intrinsic_function(false),
+            unescape: JsFunction::empty_intrinsic_function_in(mc, false),
             #[cfg(feature = "intl")]
             intl: JsObject::new_unique(None, Intl::new()?),
             #[cfg(feature = "intl")]
@@ -1434,45 +1457,56 @@ pub(crate) struct ObjectTemplates {
 }
 
 impl ObjectTemplates {
-    pub(crate) fn new(root_shape: &RootShape, constructors: &StandardConstructors) -> Self {
+    pub(crate) fn new(
+        mc: &boa_gc::MutationContext<'static, '_>,
+        root_shape: &RootShape,
+        constructors: &StandardConstructors,
+    ) -> Self {
         let root_shape = root_shape.shape();
 
         // pre-initialize used shapes.
         let ordinary_object =
-            ObjectTemplate::with_prototype(root_shape, constructors.object().prototype());
+            ObjectTemplate::with_prototype_in(mc, root_shape, constructors.object().prototype());
         let mut array = ObjectTemplate::new(root_shape);
         let length_property_key: PropertyKey = js_string!("length").into();
-        array.property(
+        array.property_in(
+            mc,
             length_property_key.clone(),
             Attribute::WRITABLE | Attribute::PERMANENT | Attribute::NON_ENUMERABLE,
         );
-        array.set_prototype(constructors.array().prototype());
-
-        let number = ObjectTemplate::with_prototype(root_shape, constructors.number().prototype());
-        let symbol = ObjectTemplate::with_prototype(root_shape, constructors.symbol().prototype());
-        let bigint = ObjectTemplate::with_prototype(root_shape, constructors.bigint().prototype());
+        array.set_prototype_in(mc, constructors.array().prototype());
+
+        let number =
+            ObjectTemplate::with_prototype_in(mc, root_shape, constructors.number().prototype());
+        let symbol =
+            ObjectTemplate::with_prototype_in(mc, root_shape, constructors.symbol().prototype());
+        let bigint =
+            ObjectTemplate::with_prototype_in(mc, root_shape, constructors.bigint().prototype());
         let boolean =
-            ObjectTemplate::with_prototype(root_shape, constructors.boolean().prototype());
+            ObjectTemplate::with_prototype_in(mc, root_shape, constructors.boolean().prototype());
         let mut string = ObjectTemplate::new(root_shape);
-        string.property(
+        string.property_in(
+            mc,
             length_property_key.clone(),
             Attribute::READONLY | Attribute::PERMANENT | Attribute::NON_ENUMERABLE,
         );
-        string.set_prototype(constructors.string().prototype());
+        string.set_prototype_in(mc, constructors.string().prototype());
 
         let mut regexp_without_proto = ObjectTemplate::new(root_shape);
-        regexp_without_proto.property(js_string!("lastIndex").into(), Attribute::WRITABLE);
+        regexp_without_proto.property_in(mc, js_string!("lastIndex").into(), Attribute::WRITABLE);
 
         let mut regexp = regexp_without_proto.clone();
-        regexp.set_prototype(constructors.regexp().prototype());
+        regexp.set_prototype_in(mc, constructors.regexp().prototype());
 
         let name_property_key: PropertyKey = js_string!("name").into();
         let mut function = ObjectTemplate::new(root_shape);
-        function.property(
+        function.property_in(
+            mc,
             length_property_key.clone(),
             Attribute::READONLY | Attribute::CONFIGURABLE | Attribute::NON_ENUMERABLE,
         );
-        function.property(
+        function.property_in(
+            mc,
             name_property_key,
             Attribute::READONLY | Attribute::CONFIGURABLE | Attribute::NON_ENUMERABLE,
         );
@@ -1481,7 +1515,8 @@ impl ObjectTemplates {
         let mut async_function = function.clone();
         let mut function_with_prototype = function.clone();
 
-        function_with_prototype.property(
+        function_with_prototype.property_in(
+            mc,
             PROTOTYPE.into(),
             Attribute::WRITABLE | Attribute::PERMANENT | Attribute::NON_ENUMERABLE,
         );
@@ -1490,14 +1525,16 @@ impl ObjectTemplates {
 
         let function_with_prototype_without_proto = function_with_prototype.clone();
 
-        function.set_prototype(constructors.function().prototype());
-        function_with_prototype.set_prototype(constructors.function().prototype());
-        async_function.set_prototype(constructors.async_function().prototype());
-        generator_function.set_prototype(constructors.generator_function().prototype());
-        async_generator_function.set_prototype(constructors.async_generator_function().prototype());
+        function.set_prototype_in(mc, constructors.function().prototype());
+        function_with_prototype.set_prototype_in(mc, constructors.function().prototype());
+        async_function.set_prototype_in(mc, constructors.async_function().prototype());
+        generator_function.set_prototype_in(mc, constructors.generator_function().prototype());
+        async_generator_function
+            .set_prototype_in(mc, constructors.async_generator_function().prototype());
 
         let mut function_prototype = ordinary_object.clone();
-        function_prototype.property(
+        function_prototype.property_in(
+            mc,
             CONSTRUCTOR.into(),
             Attribute::WRITABLE | Attribute::CONFIGURABLE | Attribute::NON_ENUMERABLE,
         );
@@ -1506,7 +1543,8 @@ impl ObjectTemplates {
 
         // 4. Perform DefinePropertyOrThrow(obj, "length", PropertyDescriptor { [[Value]]: 𝔽(len),
         // [[Writable]]: true, [[Enumerable]]: false, [[Configurable]]: true }).
-        unmapped_arguments.property(
+        unmapped_arguments.property_in(
+            mc,
             length_property_key,
             Attribute::WRITABLE | Attribute::NON_ENUMERABLE | Attribute::CONFIGURABLE,
         );
@@ -1514,7 +1552,8 @@ impl ObjectTemplates {
         // 7. Perform ! DefinePropertyOrThrow(obj, @@iterator, PropertyDescriptor {
         // [[Value]]: %Array.prototype.values%, [[Writable]]: true, [[Enumerable]]: false,
         // [[Configurable]]: true }).
-        unmapped_arguments.property(
+        unmapped_arguments.property_in(
+            mc,
             JsSymbol::iterator().into(),
             Attribute::WRITABLE | Attribute::NON_ENUMERABLE | Attribute::CONFIGURABLE,
         );
@@ -1524,7 +1563,8 @@ impl ObjectTemplates {
         // 8. Perform ! DefinePropertyOrThrow(obj, "callee", PropertyDescriptor {
         // [[Get]]: %ThrowTypeError%, [[Set]]: %ThrowTypeError%, [[Enumerable]]: false,
         // [[Configurable]]: false }).
-        unmapped_arguments.accessor(
+        unmapped_arguments.accessor_in(
+            mc,
             js_string!("callee").into(),
             true,
             true,
@@ -1533,34 +1573,37 @@ impl ObjectTemplates {
 
         // 21. Perform ! DefinePropertyOrThrow(obj, "callee", PropertyDescriptor {
         // [[Value]]: func, [[Writable]]: true, [[Enumerable]]: false, [[Configurable]]: true }).
-        mapped_arguments.property(
+        mapped_arguments.property_in(
+            mc,
             js_string!("callee").into(),
             Attribute::WRITABLE | Attribute::NON_ENUMERABLE | Attribute::CONFIGURABLE,
         );
 
         let mut iterator_result = ordinary_object.clone();
-        iterator_result.property(
+        iterator_result.property_in(
+            mc,
             js_string!("value").into(),
             Attribute::WRITABLE | Attribute::CONFIGURABLE | Attribute::ENUMERABLE,
         );
-        iterator_result.property(
+        iterator_result.property_in(
+            mc,
             js_string!("done").into(),
             Attribute::WRITABLE | Attribute::CONFIGURABLE | Attribute::ENUMERABLE,
         );
 
         let mut namespace = ObjectTemplate::new(root_shape);
-        namespace.property(JsSymbol::to_string_tag().into(), Attribute::empty());
+        namespace.property_in(mc, JsSymbol::to_string_tag().into(), Attribute::empty());
 
         let with_resolvers = {
             let mut with_resolvers = ordinary_object.clone();
 
             with_resolvers
                 // 4. Perform ! CreateDataPropertyOrThrow(obj, "promise", promiseCapability.[[Promise]]).
-                .property(js_string!("promise").into(), Attribute::all())
+                .property_in(mc, js_string!("promise").into(), Attribute::all())
                 // 5. Perform ! CreateDataPropertyOrThrow(obj, "resolve", promiseCapability.[[Resolve]]).
-                .property(js_string!("resolve").into(), Attribute::all())
+                .property_in(mc, js_string!("resolve").into(), Attribute::all())
                 // 6. Perform ! CreateDataPropertyOrThrow(obj, "reject", promiseCapability.[[Reject]]).
-                .property(js_string!("reject").into(), Attribute::all());
+                .property_in(mc, js_string!("reject").into(), Attribute::all());
 
             with_resolvers
         };
@@ -1568,8 +1611,8 @@ impl ObjectTemplates {
         let wait_async = {
             let mut obj = ordinary_object.clone();
 
-            obj.property(js_string!("async").into(), Attribute::all())
-                .property(js_string!("value").into(), Attribute::all());
+            obj.property_in(mc, js_string!("async").into(), Attribute::all())
+                .property_in(mc, js_string!("value").into(), Attribute::all());
 
             obj
         };
diff --git a/core/engine/src/context/mod.rs b/core/engine/src/context/mod.rs
index bd0aa5783db..218d177ffda 100644
--- a/core/engine/src/context/mod.rs
+++ b/core/engine/src/context/mod.rs
@@ -474,10 +474,9 @@ impl Context {
         self.gc.alloc(value)
     }
 
-    /// Returns the active collector.
-    #[inline]
+    /// Gets the GC collector.
     #[must_use]
-    pub fn gc_collector(&self) -> &boa_gc::MutationContext<'static, 'static> {
+    pub fn gc_collector(&self) -> &'static boa_gc::MutationContext<'static, 'static> {
         self.gc.gc_collector()
     }
 
@@ -549,7 +548,9 @@ impl Context {
 
     /// Create a new Realm with the default global bindings.
     pub fn create_realm(&mut self) -> JsResult<Realm> {
-        let realm = Realm::create(self.host_hooks.as_ref(), &self.root_shape)?;
+        let realm = Realm::create(self.host_hooks.as_ref(), &self.root_shape, &unsafe {
+            boa_gc::MutationContext::global()
+        })?;
 
         let old_realm = self.enter_realm(realm);
 
@@ -1223,12 +1224,13 @@ impl ContextBuilder {
             CANNOT_BLOCK_COUNTER.set(CANNOT_BLOCK_COUNTER.get() + 1);
         }
 
-        let root_shape = RootShape::default();
+        let mc = unsafe { boa_gc::MutationContext::global() };
+        let root_shape = RootShape::new_in(&mc);
 
         let host_hooks = self.host_hooks.unwrap_or(Rc::new(DefaultHooks));
         let clock = self.clock.unwrap_or_else(|| Rc::new(StdClock::new()));
-        let realm = Realm::create(host_hooks.as_ref(), &root_shape)?;
-        let vm = Vm::new(realm);
+        let realm = Realm::create(host_hooks.as_ref(), &root_shape, &mc)?;
+        let vm = Vm::new(realm, &mc);
 
         let module_loader: Rc<dyn DynModuleLoader> = if let Some(loader) = self.module_loader {
             loader
diff --git a/core/engine/src/environments/runtime/mod.rs b/core/engine/src/environments/runtime/mod.rs
index 59724b87c38..4e47a4f79ff 100644
--- a/core/engine/src/environments/runtime/mod.rs
+++ b/core/engine/src/environments/runtime/mod.rs
@@ -216,7 +216,7 @@ impl EnvironmentStack {
         &mut self,
         bindings_count: u32,
         global: &Gc<'static, DeclarativeEnvironment>,
-        gc: boa_gc::MutationContext<'static, '_>,
+        gc: &boa_gc::MutationContext<'static, '_>,
     ) -> u32 {
         let (poisoned, with) = self.compute_poisoned_with(global);
 
@@ -240,14 +240,14 @@ impl EnvironmentStack {
         scope: Scope,
         function_slots: FunctionSlots,
         global: &Gc<'static, DeclarativeEnvironment>,
-        gc: boa_gc::MutationContext<'static, '_>,
+        gc: &boa_gc::MutationContext<'static, '_>,
     ) {
         let num_bindings = scope.num_bindings_non_local();
 
         let (poisoned, with) = self.compute_poisoned_with(global);
 
         self.push_env(Environment::Declarative(Gc::new(
-            &gc,
+            gc,
             DeclarativeEnvironment::new(
                 DeclarativeEnvironmentKind::Function(FunctionEnvironment::new(
                     num_bindings,
@@ -261,10 +261,10 @@ impl EnvironmentStack {
     }
 
     /// Push a module environment on the environments stack.
-    pub(crate) fn push_module(&mut self, scope: Scope, gc: boa_gc::MutationContext<'static, '_>) {
+    pub(crate) fn push_module(&mut self, scope: Scope, gc: &boa_gc::MutationContext<'static, '_>) {
         let num_bindings = scope.num_bindings_non_local();
         self.push_env(Environment::Declarative(Gc::new(
-            &gc,
+            gc,
             DeclarativeEnvironment::new(
                 DeclarativeEnvironmentKind::Module(ModuleEnvironment::new(num_bindings, scope)),
                 false,
diff --git a/core/engine/src/module/source.rs b/core/engine/src/module/source.rs
index 2f32a2d2cb3..c7962cc5b32 100644
--- a/core/engine/src/module/source.rs
+++ b/core/engine/src/module/source.rs
@@ -1645,6 +1645,7 @@ impl SourceTextModule {
         let env = source.scope().clone();
 
         let spanned_source_text = SpannedSourceText::new_source_only(source_text.clone());
+        let mc = context.gc_collector();
         let mut compiler = ByteCompiler::new(
             js_string!("<main>"),
             true,
@@ -1654,6 +1655,7 @@ impl SourceTextModule {
             self.code.has_tla,
             false,
             context.interner_mut(),
+            &mc,
             false,
             spanned_source_text,
             self.code.path.clone().into(),
@@ -1834,7 +1836,7 @@ impl SourceTextModule {
 
         // 8. Let moduleContext be a new ECMAScript code execution context.
         let mut envs = EnvironmentStack::new();
-        envs.push_module(source.scope().clone(), unsafe {
+        envs.push_module(source.scope().clone(), &unsafe {
             boa_gc::MutationContext::global()
         });
         drop(status);
diff --git a/core/engine/src/module/synthetic.rs b/core/engine/src/module/synthetic.rs
index 888c0db39cf..f0bbde545fa 100644
--- a/core/engine/src/module/synthetic.rs
+++ b/core/engine/src/module/synthetic.rs
@@ -311,6 +311,7 @@ impl SyntheticModule {
 
         // TODO: A bit of a hack to be able to pass the currently active runnable without an
         // available codeblock to execute.
+        let mc = context.gc_collector();
         let compiler = ByteCompiler::new(
             js_string!("<synthetic>"),
             true,
@@ -320,6 +321,7 @@ impl SyntheticModule {
             false,
             false,
             context.interner_mut(),
+            &mc,
             false,
             // A synthetic module does not contain `SourceText`
             SpannedSourceText::new_empty(),
@@ -342,7 +344,7 @@ impl SyntheticModule {
         let cb = context.alloc(finished);
 
         let mut envs = EnvironmentStack::new();
-        envs.push_module(module_scope, unsafe { boa_gc::MutationContext::global() });
+        envs.push_module(module_scope, &unsafe { boa_gc::MutationContext::global() });
 
         for locator in exports {
             //     b. Perform ! env.InitializeBinding(exportName, undefined).
diff --git a/core/engine/src/object/builtins/jsfunction.rs b/core/engine/src/object/builtins/jsfunction.rs
index c1bc9d152e8..0d165e0c17c 100644
--- a/core/engine/src/object/builtins/jsfunction.rs
+++ b/core/engine/src/object/builtins/jsfunction.rs
@@ -122,14 +122,14 @@ impl JsFunction {
         Self { inner: object }
     }
 
-    /// Creates a new, empty intrinsic function object with only its function internal methods set.
-    ///
-    /// Mainly used to initialize objects before a [`Context`] is available to do so.
-    ///
-    /// [`Context`]: crate::Context
-    pub(crate) fn empty_intrinsic_function(constructor: bool) -> Self {
+    /// Creates a new, empty intrinsic function object with only its function internal methods set, using the given context.
+    pub(crate) fn empty_intrinsic_function_in(
+        mc: &boa_gc::MutationContext<'static, '_>,
+        constructor: bool,
+    ) -> Self {
         Self {
-            inner: JsObject::from_proto_and_data(
+            inner: JsObject::from_proto_and_data_in(
+                mc,
                 None,
                 NativeFunctionObject {
                     f: NativeFunction::from_fn_ptr(|_, _, _| Ok(JsValue::undefined())),
@@ -141,6 +141,18 @@ impl JsFunction {
         }
     }
 
+    /// Creates a new, empty intrinsic function object with only its function internal methods set.
+    ///
+    /// Mainly used to initialize objects before a [`Context`] is available to do so.
+    ///
+    /// [`Context`]: crate::Context
+    pub(crate) fn empty_intrinsic_function(constructor: bool) -> Self {
+        Self::empty_intrinsic_function_in(
+            &unsafe { boa_gc::MutationContext::global() },
+            constructor,
+        )
+    }
+
     /// Creates a [`JsFunction`] from a [`JsObject`], or returns `None` if the object is not a function.
     ///
     /// This does not clone the fields of the function, it only does a shallow clone of the object.
diff --git a/core/engine/src/object/jsobject.rs b/core/engine/src/object/jsobject.rs
index 711bb3cee2b..10cfd824459 100644
--- a/core/engine/src/object/jsobject.rs
+++ b/core/engine/src/object/jsobject.rs
@@ -116,13 +116,14 @@ impl JsObject {
         Self::with_object_proto(intrinsics)
     }
 
-    /// Creates a new `JsObject` from its inner object and its vtable.
-    pub(crate) fn from_object_and_vtable<T: NativeObject>(
+    /// Creates a new `JsObject` from its inner object and its vtable using the given context.
+    pub(crate) fn from_object_and_vtable_in<T: NativeObject>(
+        mc: &boa_gc::MutationContext<'static, '_>,
         object: Object<T>,
         vtable: &'static InternalObjectMethods,
     ) -> Self {
         let inner = Gc::new(
-            &unsafe { boa_gc::MutationContext::global() },
+            mc,
             VTableObject {
                 object: GcRefCell::new(object),
                 vtable,
@@ -132,6 +133,18 @@ impl JsObject {
         JsObject { inner }.upcast()
     }
 
+    /// Creates a new `JsObject` from its inner object and its vtable.
+    pub(crate) fn from_object_and_vtable<T: NativeObject>(
+        object: Object<T>,
+        vtable: &'static InternalObjectMethods,
+    ) -> Self {
+        Self::from_object_and_vtable_in(
+            &unsafe { boa_gc::MutationContext::global() },
+            object,
+            vtable,
+        )
+    }
+
     /// Creates a new ordinary object with its prototype set to the `Object` prototype.
     ///
     /// This is equivalent to calling the specification's abstract operation
@@ -158,6 +171,13 @@ impl JsObject {
         )
     }
 
+    /// Creates a new ordinary object, with its prototype set to null using the given context.
+    #[inline]
+    #[must_use]
+    pub fn with_null_proto_in(mc: &boa_gc::MutationContext<'static, '_>) -> Self {
+        Self::from_proto_and_data_in(mc, None, OrdinaryObject)
+    }
+
     /// Creates a new ordinary object, with its prototype set to null.
     ///
     /// This is equivalent to calling the specification's abstract operation
@@ -176,7 +196,30 @@ impl JsObject {
     #[inline]
     #[must_use]
     pub fn with_null_proto() -> Self {
-        Self::from_proto_and_data(None, OrdinaryObject)
+        Self::with_null_proto_in(&unsafe { boa_gc::MutationContext::global() })
+    }
+
+    /// Creates a new object with the provided prototype and object data, using the given context.
+    pub fn from_proto_and_data_in<O: Into<Option<Self>>, T: NativeObject>(
+        mc: &boa_gc::MutationContext<'static, '_>,
+        prototype: O,
+        data: T,
+    ) -> Self {
+        let internal_methods = data.internal_methods();
+        let inner = Gc::new(
+            mc,
+            VTableObject {
+                object: GcRefCell::new(Object {
+                    data: ObjectData::new(data),
+                    properties: PropertyMap::from_prototype_unique_shape(prototype.into()),
+                    extensible: true,
+                    private_elements: ThinVec::new(),
+                }),
+                vtable: internal_methods,
+            },
+        );
+
+        JsObject { inner }.upcast()
     }
 
     /// Creates a new object with the provided prototype and object data.
@@ -209,13 +252,33 @@ impl JsObject {
         prototype: O,
         data: T,
     ) -> Self {
+        Self::from_proto_and_data_in(
+            &unsafe { boa_gc::MutationContext::global() },
+            prototype,
+            data,
+        )
+    }
+
+    /// Creates a new object with the provided prototype and object data using the given context.
+    pub(crate) fn from_proto_and_data_with_shared_shape_in<
+        O: Into<Option<Self>>,
+        T: NativeObject,
+    >(
+        mc: &boa_gc::MutationContext<'static, '_>,
+        root_shape: &RootShape,
+        prototype: O,
+        data: T,
+    ) -> JsObject<T> {
         let internal_methods = data.internal_methods();
         let inner = Gc::new(
-            &unsafe { boa_gc::MutationContext::global() },
+            mc,
             VTableObject {
                 object: GcRefCell::new(Object {
                     data: ObjectData::new(data),
-                    properties: PropertyMap::from_prototype_unique_shape(prototype.into()),
+                    properties: PropertyMap::from_prototype_with_shared_shape(
+                        root_shape,
+                        prototype.into(),
+                    ),
                     extensible: true,
                     private_elements: ThinVec::new(),
                 }),
@@ -223,7 +286,7 @@ impl JsObject {
             },
         );
 
-        JsObject { inner }.upcast()
+        JsObject { inner }
     }
 
     /// Creates a new object with the provided prototype and object data.
@@ -238,24 +301,12 @@ impl JsObject {
         prototype: O,
         data: T,
     ) -> JsObject<T> {
-        let internal_methods = data.internal_methods();
-        let inner = Gc::new(
+        Self::from_proto_and_data_with_shared_shape_in(
             &unsafe { boa_gc::MutationContext::global() },
-            VTableObject {
-                object: GcRefCell::new(Object {
-                    data: ObjectData::new(data),
-                    properties: PropertyMap::from_prototype_with_shared_shape(
-                        root_shape,
-                        prototype.into(),
-                    ),
-                    extensible: true,
-                    private_elements: ThinVec::new(),
-                }),
-                vtable: internal_methods,
-            },
-        );
-
-        JsObject { inner }
+            root_shape,
+            prototype,
+            data,
+        )
     }
 
     /// Downcasts the object's inner data if the object is of type `T`.
@@ -1057,6 +1108,33 @@ impl<T: NativeObject> JsObject<T> {
 }
 
 impl<T: NativeObject> JsObject<T> {
+    /// Creates a new `JsObject` from a `RootShape`, prototype, and data using the given context.
+    pub fn new_in<O: Into<Option<JsObject>>>(
+        mc: &boa_gc::MutationContext<'static, '_>,
+        root_shape: &RootShape,
+        prototype: O,
+        data: T,
+    ) -> Self {
+        let internal_methods = data.internal_methods();
+        let inner = Gc::new(
+            mc,
+            VTableObject {
+                object: GcRefCell::new(Object {
+                    data: ObjectData::new(data),
+                    properties: PropertyMap::from_prototype_with_shared_shape(
+                        root_shape,
+                        prototype.into(),
+                    ),
+                    extensible: true,
+                    private_elements: ThinVec::new(),
+                }),
+                vtable: internal_methods,
+            },
+        );
+
+        Self { inner }
+    }
+
     /// Creates a new `JsObject` from its root shape, prototype, and data.
     ///
     /// Note that the returned object will not be erased to be convertible to a
@@ -1080,16 +1158,27 @@ impl<T: NativeObject> JsObject<T> {
     /// assert!(obj.is_ordinary());
     /// ```
     pub fn new<O: Into<Option<JsObject>>>(root_shape: &RootShape, prototype: O, data: T) -> Self {
+        Self::new_in(
+            &unsafe { boa_gc::MutationContext::global() },
+            root_shape,
+            prototype,
+            data,
+        )
+    }
+
+    /// Creates a new `JsObject` from prototype, and data using the given context.
+    pub fn new_unique_in<O: Into<Option<JsObject>>>(
+        mc: &boa_gc::MutationContext<'static, '_>,
+        prototype: O,
+        data: T,
+    ) -> Self {
         let internal_methods = data.internal_methods();
         let inner = Gc::new(
-            &unsafe { boa_gc::MutationContext::global() },
+            mc,
             VTableObject {
                 object: GcRefCell::new(Object {
                     data: ObjectData::new(data),
-                    properties: PropertyMap::from_prototype_with_shared_shape(
-                        root_shape,
-                        prototype.into(),
-                    ),
+                    properties: PropertyMap::from_prototype_unique_shape(prototype.into()),
                     extensible: true,
                     private_elements: ThinVec::new(),
                 }),
@@ -1118,21 +1207,11 @@ impl<T: NativeObject> JsObject<T> {
     /// assert!(obj.prototype().is_none());
     /// ```
     pub fn new_unique<O: Into<Option<JsObject>>>(prototype: O, data: T) -> Self {
-        let internal_methods = data.internal_methods();
-        let inner = Gc::new(
+        Self::new_unique_in(
             &unsafe { boa_gc::MutationContext::global() },
-            VTableObject {
-                object: GcRefCell::new(Object {
-                    data: ObjectData::new(data),
-                    properties: PropertyMap::from_prototype_unique_shape(prototype.into()),
-                    extensible: true,
-                    private_elements: ThinVec::new(),
-                }),
-                vtable: internal_methods,
-            },
-        );
-
-        Self { inner }
+            prototype,
+            data,
+        )
     }
 
     /// Upcasts this object's inner data from a specific type `T` to an erased type
diff --git a/core/engine/src/object/shape/mod.rs b/core/engine/src/object/shape/mod.rs
index bfb7b512183..e4c5889093d 100644
--- a/core/engine/src/object/shape/mod.rs
+++ b/core/engine/src/object/shape/mod.rs
@@ -103,33 +103,45 @@ impl Shape {
         None
     }
 
-    /// Create an insert property transitions returning the new transitioned [`Shape`].
+    /// Create an insert property transitions returning the new transitioned [`Shape`] using the given context.
     ///
     /// NOTE: This assumes that there is no property with the given key!
-    pub(crate) fn insert_property_transition(&self, key: TransitionKey) -> Self {
+    pub(crate) fn insert_property_transition_in(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        key: TransitionKey,
+    ) -> Self {
         match &self.inner {
             Inner::Shared(shape) => {
-                let shape = shape.insert_property_transition(key);
+                let shape = shape.insert_property_transition_in(mc, key);
                 if shape.transition_count() >= Self::TRANSITION_COUNT_MAX {
                     return shape.to_unique().into();
                 }
                 shape.into()
             }
-            Inner::Unique(shape) => shape.insert_property_transition(key).into(),
+            Inner::Unique(shape) => shape.insert_property_transition(key).into(), // UniqueShape insert doesn't allocate new GC
         }
     }
 
+    /// Create an insert property transitions returning the new transitioned [`Shape`].
+    ///
+    /// NOTE: This assumes that there is no property with the given key!
+    pub(crate) fn insert_property_transition(&self, key: TransitionKey) -> Self {
+        self.insert_property_transition_in(&unsafe { boa_gc::MutationContext::global() }, key)
+    }
+
     /// Create a change attribute property transitions returning [`ChangeTransition`] containing the new [`Shape`]
-    /// and actions to be performed
+    /// and actions to be performed, using the given context.
     ///
     /// NOTE: This assumes that there already is a property with the given key!
-    pub(crate) fn change_attributes_transition(
+    pub(crate) fn change_attributes_transition_in(
         &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
         key: TransitionKey,
     ) -> ChangeTransition<Self> {
         match &self.inner {
             Inner::Shared(shape) => {
-                let change_transition = shape.change_attributes_transition(key);
+                let change_transition = shape.change_attributes_transition_in(mc, key);
                 let shape =
                     if change_transition.shape.transition_count() >= Self::TRANSITION_COUNT_MAX {
                         change_transition.shape.to_unique().into()
@@ -145,13 +157,28 @@ impl Shape {
         }
     }
 
-    /// Remove a property property from the [`Shape`] returning the new transitioned [`Shape`].
+    /// Create a change attribute property transitions returning [`ChangeTransition`] containing the new [`Shape`]
+    /// and actions to be performed
     ///
     /// NOTE: This assumes that there already is a property with the given key!
-    pub(crate) fn remove_property_transition(&self, key: &PropertyKey) -> Self {
+    pub(crate) fn change_attributes_transition(
+        &self,
+        key: TransitionKey,
+    ) -> ChangeTransition<Self> {
+        self.change_attributes_transition_in(&unsafe { boa_gc::MutationContext::global() }, key)
+    }
+
+    /// Remove a property from the [`Shape`] returning the new transitioned [`Shape`] using the given context.
+    ///
+    /// NOTE: This assumes that there already is a property with the given key!
+    pub(crate) fn remove_property_transition_in(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        key: &PropertyKey,
+    ) -> Self {
         match &self.inner {
             Inner::Shared(shape) => {
-                let shape = shape.remove_property_transition(key);
+                let shape = shape.remove_property_transition_in(mc, key);
                 if shape.transition_count() >= Self::TRANSITION_COUNT_MAX {
                     return shape.to_unique().into();
                 }
@@ -161,11 +188,22 @@ impl Shape {
         }
     }
 
-    /// Create a prototype transitions returning the new transitioned [`Shape`].
-    pub(crate) fn change_prototype_transition(&self, prototype: JsPrototype) -> Self {
+    /// Remove a property from the [`Shape`] returning the new transitioned [`Shape`].
+    ///
+    /// NOTE: This assumes that there already is a property with the given key!
+    pub(crate) fn remove_property_transition(&self, key: &PropertyKey) -> Self {
+        self.remove_property_transition_in(&unsafe { boa_gc::MutationContext::global() }, key)
+    }
+
+    /// Create a prototype transition returning the new transitioned [`Shape`] using the given context.
+    pub(crate) fn change_prototype_transition_in(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        prototype: JsPrototype,
+    ) -> Self {
         match &self.inner {
             Inner::Shared(shape) => {
-                let shape = shape.change_prototype_transition(prototype);
+                let shape = shape.change_prototype_transition_in(mc, prototype);
                 if shape.transition_count() >= Self::TRANSITION_COUNT_MAX {
                     return shape.to_unique().into();
                 }
@@ -175,6 +213,14 @@ impl Shape {
         }
     }
 
+    /// Create a prototype transition returning the new transitioned [`Shape`].
+    pub(crate) fn change_prototype_transition(&self, prototype: JsPrototype) -> Self {
+        self.change_prototype_transition_in(
+            &unsafe { boa_gc::MutationContext::global() },
+            prototype,
+        )
+    }
+
     /// Get the [`JsPrototype`] of the [`Shape`].
     #[must_use]
     pub fn prototype(&self) -> JsPrototype {
diff --git a/core/engine/src/object/shape/root_shape.rs b/core/engine/src/object/shape/root_shape.rs
index 9cc3de38e59..278bddc6935 100644
--- a/core/engine/src/object/shape/root_shape.rs
+++ b/core/engine/src/object/shape/root_shape.rs
@@ -13,13 +13,18 @@ pub struct RootShape {
 impl Default for RootShape {
     #[inline]
     fn default() -> Self {
-        Self {
-            shape: SharedShape::root(),
-        }
+        Self::new_in(&unsafe { boa_gc::MutationContext::global() })
     }
 }
 
 impl RootShape {
+    /// Create a new root shape using the given context.
+    #[inline]
+    pub(crate) fn new_in(mc: &boa_gc::MutationContext<'static, '_>) -> Self {
+        Self {
+            shape: SharedShape::root_in(mc),
+        }
+    }
     /// Gets the inner [`SharedShape`].
     #[must_use]
     pub const fn shape(&self) -> &SharedShape {
diff --git a/core/engine/src/object/shape/shared_shape/forward_transition.rs b/core/engine/src/object/shape/shared_shape/forward_transition.rs
index 88c286171d3..5846c7916b9 100644
--- a/core/engine/src/object/shape/shared_shape/forward_transition.rs
+++ b/core/engine/src/object/shape/shared_shape/forward_transition.rs
@@ -55,9 +55,10 @@ pub(super) struct ForwardTransition {
 }
 
 impl ForwardTransition {
-    /// Insert a property transition.
-    pub(super) fn insert_property(
+    /// Insert a property transition using the given context.
+    pub(super) fn insert_property_in(
         &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
         key: TransitionKey,
         value: &Gc<'static, SharedShapeInner>,
     ) {
@@ -68,14 +69,25 @@ impl ForwardTransition {
             properties.map.retain(|_, v| v.is_upgradable());
         }
 
-        properties.map.insert(
-            key,
-            WeakGc::new(&unsafe { boa_gc::MutationContext::global() }, value),
-        );
+        properties.map.insert(key, WeakGc::new(mc, value));
     }
 
-    /// Insert a prototype transition.
-    pub(super) fn insert_prototype(&self, key: JsPrototype, value: &Gc<'static, SharedShapeInner>) {
+    /// Insert a property transition.
+    pub(super) fn insert_property(
+        &self,
+        key: TransitionKey,
+        value: &Gc<'static, SharedShapeInner>,
+    ) {
+        self.insert_property_in(&unsafe { boa_gc::MutationContext::global() }, key, value)
+    }
+
+    /// Insert a prototype transition using the given context.
+    pub(super) fn insert_prototype_in(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        key: JsPrototype,
+        value: &Gc<'static, SharedShapeInner>,
+    ) {
         let mut this = self.inner.borrow_mut();
         let prototypes = this.prototypes.get_or_insert_with(Box::default);
 
@@ -83,10 +95,12 @@ impl ForwardTransition {
             prototypes.map.retain(|_, v| v.is_upgradable());
         }
 
-        prototypes.map.insert(
-            key,
-            WeakGc::new(&unsafe { boa_gc::MutationContext::global() }, value),
-        );
+        prototypes.map.insert(key, WeakGc::new(mc, value));
+    }
+
+    /// Insert a prototype transition.
+    pub(super) fn insert_prototype(&self, key: JsPrototype, value: &Gc<'static, SharedShapeInner>) {
+        self.insert_prototype_in(&unsafe { boa_gc::MutationContext::global() }, key, value)
     }
 
     /// Get a property transition, return [`None`] otherwise.
diff --git a/core/engine/src/object/shape/shared_shape/mod.rs b/core/engine/src/object/shape/shared_shape/mod.rs
index cbbfb1dbecb..3448ac5455a 100644
--- a/core/engine/src/object/shape/shared_shape/mod.rs
+++ b/core/engine/src/object/shape/shared_shape/mod.rs
@@ -163,32 +163,50 @@ impl SharedShape {
         self.inner.prototype.as_ref() == Some(prototype)
     }
 
-    /// Create a new [`SharedShape`].
-    fn new(inner: Inner) -> Self {
+    /// Create a new [`SharedShape`] using the given context.
+    fn new_in(mc: &boa_gc::MutationContext<'static, '_>, inner: Inner) -> Self {
         Self {
-            inner: Gc::new(&unsafe { boa_gc::MutationContext::global() }, inner),
+            inner: Gc::new(mc, inner),
         }
     }
 
+    /// Create a new [`SharedShape`].
+    fn new(inner: Inner) -> Self {
+        Self::new_in(&unsafe { boa_gc::MutationContext::global() }, inner)
+    }
+
+    /// Create a root [`SharedShape`] using the given context.
+    #[must_use]
+    pub(crate) fn root_in(mc: &boa_gc::MutationContext<'static, '_>) -> Self {
+        Self::new_in(
+            mc,
+            Inner {
+                forward_transitions: ForwardTransition::default(),
+                prototype: None,
+                property_count: 0,
+                // Most of the time the root shape initiates with between 1-4 properties.
+                property_table: PropertyTable::with_capacity(4),
+                previous: None,
+                flags: ShapeFlags::default(),
+                transition_count: 0,
+            },
+        )
+    }
+
     /// Create a root [`SharedShape`].
     #[must_use]
     pub(crate) fn root() -> Self {
-        Self::new(Inner {
-            forward_transitions: ForwardTransition::default(),
-            prototype: None,
-            property_count: 0,
-            // Most of the time the root shape initiates with between 1-4 properties.
-            property_table: PropertyTable::with_capacity(4),
-            previous: None,
-            flags: ShapeFlags::default(),
-            transition_count: 0,
-        })
+        Self::root_in(&unsafe { boa_gc::MutationContext::global() })
     }
 
-    /// Create a [`SharedShape`] change prototype transition.
-    pub(crate) fn change_prototype_transition(&self, prototype: JsPrototype) -> Self {
+    /// Create a [`SharedShape`] change prototype transition using the given context.
+    pub(crate) fn change_prototype_transition_in(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        prototype: JsPrototype,
+    ) -> Self {
         if let Some(shape) = self.forward_transitions().get_prototype(&prototype) {
-            if let Some(inner) = shape.upgrade(&unsafe { boa_gc::MutationContext::global() }) {
+            if let Some(inner) = shape.upgrade(mc) {
                 return Self { inner };
             }
 
@@ -203,7 +221,7 @@ impl SharedShape {
             transition_count: self.transition_count() + 1,
             flags: ShapeFlags::prototype_transition_from(self.flags()),
         };
-        let new_shape = Self::new(new_inner_shape);
+        let new_shape = Self::new_in(mc, new_inner_shape);
 
         self.forward_transitions()
             .insert_prototype(prototype, &new_shape.inner);
@@ -211,11 +229,23 @@ impl SharedShape {
         new_shape
     }
 
-    /// Create a [`SharedShape`] insert property transition.
-    pub(crate) fn insert_property_transition(&self, key: TransitionKey) -> Self {
+    /// Create a [`SharedShape`] change prototype transition.
+    pub(crate) fn change_prototype_transition(&self, prototype: JsPrototype) -> Self {
+        self.change_prototype_transition_in(
+            &unsafe { boa_gc::MutationContext::global() },
+            prototype,
+        )
+    }
+
+    /// Create a [`SharedShape`] insert property transition using the given context.
+    pub(crate) fn insert_property_transition_in(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        key: TransitionKey,
+    ) -> Self {
         // Check if we have already created such a transition, if so use it!
         if let Some(shape) = self.forward_transitions().get_property(&key) {
-            if let Some(inner) = shape.upgrade(&unsafe { boa_gc::MutationContext::global() }) {
+            if let Some(inner) = shape.upgrade(mc) {
                 return Self { inner };
             }
 
@@ -236,7 +266,7 @@ impl SharedShape {
             transition_count: self.transition_count() + 1,
             flags: ShapeFlags::insert_property_transition_from(self.flags()),
         };
-        let new_shape = Self::new(new_inner_shape);
+        let new_shape = Self::new_in(mc, new_inner_shape);
 
         self.forward_transitions()
             .insert_property(key, &new_shape.inner);
@@ -244,16 +274,30 @@ impl SharedShape {
         new_shape
     }
 
+    /// Create a [`SharedShape`] insert property transition.
+    pub(crate) fn insert_property_transition(&self, key: TransitionKey) -> Self {
+        self.insert_property_transition_in(&unsafe { boa_gc::MutationContext::global() }, key)
+    }
+
     /// Create a [`SharedShape`] change prototype transition, returning [`ChangeTransition`].
     pub(crate) fn change_attributes_transition(
         &self,
         key: TransitionKey,
+    ) -> ChangeTransition<Self> {
+        self.change_attributes_transition_in(&unsafe { boa_gc::MutationContext::global() }, key)
+    }
+
+    /// Create a [`SharedShape`] change prototype transition using the given context, returning [`ChangeTransition`].
+    pub(crate) fn change_attributes_transition_in(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        key: TransitionKey,
     ) -> ChangeTransition<Self> {
         let slot = self.property_table().get_expect(&key.property_key);
 
         // Check if we have already created such a transition, if so use it!
         if let Some(shape) = self.forward_transitions().get_property(&key) {
-            if let Some(inner) = shape.upgrade(&unsafe { boa_gc::MutationContext::global() }) {
+            if let Some(inner) = shape.upgrade(mc) {
                 let action = if slot.attributes.width_match(key.attributes) {
                     ChangeTransitionAction::Nothing
                 } else if slot.attributes.is_accessor_descriptor() {
@@ -412,13 +456,17 @@ impl SharedShape {
         (base, prototype, transitions)
     }
 
-    /// Remove a property from [`SharedShape`], returning the new [`SharedShape`].
-    pub(crate) fn remove_property_transition(&self, key: &PropertyKey) -> Self {
+    /// Remove a property from [`SharedShape`], returning the new [`SharedShape`] using the given context.
+    pub(crate) fn remove_property_transition_in(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        key: &PropertyKey,
+    ) -> Self {
         let (mut base, prototype, transitions) = self.rollback_before(key);
 
         // Apply prototype transition, if it was found.
         if let Some(prototype) = prototype {
-            base = base.change_prototype_transition(prototype);
+            base = base.change_prototype_transition_in(mc, prototype);
         }
 
         for (property_key, attributes) in transitions.into_iter().rev() {
@@ -426,12 +474,17 @@ impl SharedShape {
                 property_key,
                 attributes,
             };
-            base = base.insert_property_transition(transition);
+            base = base.insert_property_transition_in(mc, transition);
         }
 
         base
     }
 
+    /// Remove a property from [`SharedShape`], returning the new [`SharedShape`].
+    pub(crate) fn remove_property_transition(&self, key: &PropertyKey) -> Self {
+        self.remove_property_transition_in(&unsafe { boa_gc::MutationContext::global() }, key)
+    }
+
     /// Do a property lookup, returns [`None`] if property not found.
     pub(crate) fn lookup(&self, key: &PropertyKey) -> Option<Slot> {
         let property_count = self.property_count();
@@ -481,27 +534,39 @@ pub(crate) struct WeakSharedShape {
 
 impl WeakSharedShape {
     /// Upgrade returns a [`SharedShape`] pointer for the internal value if the pointer is still live,
-    /// or [`None`] if the value was already garbage collected.
+    /// or [`None`] if the value was already garbage collected, using the given context.
     #[inline]
     #[must_use]
-    pub(crate) fn upgrade(&self) -> Option<SharedShape> {
+    pub(crate) fn upgrade_in(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+    ) -> Option<SharedShape> {
         Some(SharedShape {
-            inner: self
-                .inner
-                .upgrade(&unsafe { boa_gc::MutationContext::global() })?,
+            inner: self.inner.upgrade(mc)?,
         })
     }
 
+    /// Upgrade returns a [`SharedShape`] pointer for the internal value if the pointer is still live,
+    /// or [`None`] if the value was already garbage collected.
+    #[inline]
+    #[must_use]
+    pub(crate) fn upgrade(&self) -> Option<SharedShape> {
+        self.upgrade_in(&unsafe { boa_gc::MutationContext::global() })
+    }
+
     #[allow(dead_code)]
     pub(crate) fn is_upgradable(&self) -> bool {
         self.inner.is_upgradable()
     }
+    pub(crate) fn new_in(mc: &boa_gc::MutationContext<'static, '_>, value: &SharedShape) -> Self {
+        WeakSharedShape {
+            inner: WeakGc::new(mc, &value.inner),
+        }
+    }
 }
 
 impl From<&SharedShape> for WeakSharedShape {
     fn from(value: &SharedShape) -> Self {
-        WeakSharedShape {
-            inner: WeakGc::new(&unsafe { boa_gc::MutationContext::global() }, &value.inner),
-        }
+        Self::new_in(&unsafe { boa_gc::MutationContext::global() }, value)
     }
 }
diff --git a/core/engine/src/object/shape/shared_shape/template.rs b/core/engine/src/object/shape/shared_shape/template.rs
index 2e6c9fb90cb..0359b79153a 100644
--- a/core/engine/src/object/shape/shared_shape/template.rs
+++ b/core/engine/src/object/shape/shared_shape/template.rs
@@ -27,10 +27,23 @@ impl ObjectTemplate {
         }
     }
 
+    /// Create and [`ObjectTemplate`] with a prototype using the given context.
+    pub(crate) fn with_prototype_in(
+        mc: &boa_gc::MutationContext<'static, '_>,
+        shape: &SharedShape,
+        prototype: JsObject,
+    ) -> Self {
+        let shape = shape.change_prototype_transition_in(mc, Some(prototype));
+        Self { shape }
+    }
+
     /// Create and [`ObjectTemplate`] with a prototype.
     pub(crate) fn with_prototype(shape: &SharedShape, prototype: JsObject) -> Self {
-        let shape = shape.change_prototype_transition(Some(prototype));
-        Self { shape }
+        Self::with_prototype_in(
+            &unsafe { boa_gc::MutationContext::global() },
+            shape,
+            prototype,
+        )
     }
 
     /// Check if the shape has a specific, prototype.
@@ -38,12 +51,25 @@ impl ObjectTemplate {
         self.shape.has_prototype(prototype)
     }
 
+    /// Set the prototype of the [`ObjectTemplate`] using the given context.
+    ///
+    /// This assumes that the prototype has not been set yet.
+    pub(crate) fn set_prototype_in(
+        &mut self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        prototype: JsObject,
+    ) -> &mut Self {
+        self.shape = self
+            .shape
+            .change_prototype_transition_in(mc, Some(prototype));
+        self
+    }
+
     /// Set the prototype of the [`ObjectTemplate`].
     ///
     /// This assumes that the prototype has not been set yet.
     pub(crate) fn set_prototype(&mut self, prototype: JsObject) -> &mut Self {
-        self.shape = self.shape.change_prototype_transition(Some(prototype));
-        self
+        self.set_prototype_in(&unsafe { boa_gc::MutationContext::global() }, prototype)
     }
 
     /// Returns the inner shape of the [`ObjectTemplate`].
@@ -51,33 +77,51 @@ impl ObjectTemplate {
         &self.shape
     }
 
-    /// Add a data property to the [`ObjectTemplate`].
+    /// Add a data property to the [`ObjectTemplate`] using the given context.
     ///
     /// This assumes that the property with the given key was not previously set
     /// and that it's a string or symbol.
-    pub(crate) fn property(&mut self, key: PropertyKey, attributes: Attribute) -> &mut Self {
+    pub(crate) fn property_in(
+        &mut self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        key: PropertyKey,
+        attributes: Attribute,
+    ) -> &mut Self {
         debug_assert!(!matches!(&key, PropertyKey::Index(_)));
 
-        let attributes = SlotAttributes::from_bits_truncate(attributes.bits());
-        self.shape = self.shape.insert_property_transition(TransitionKey {
+        let transition = TransitionKey {
             property_key: key,
-            attributes,
-        });
+            attributes: SlotAttributes::from_bits_truncate(attributes.bits()),
+        };
+        self.shape = self.shape.insert_property_transition_in(mc, transition);
         self
     }
 
+    /// Add a data property to the [`ObjectTemplate`].
+    ///
+    /// This assumes that the property with the given key was not previously set
+    /// and that it's a string or symbol.
+    pub(crate) fn property(&mut self, key: PropertyKey, attributes: Attribute) -> &mut Self {
+        self.property_in(
+            &unsafe { boa_gc::MutationContext::global() },
+            key,
+            attributes,
+        )
+    }
+
     /// Add a accessor property to the [`ObjectTemplate`].
     ///
     /// This assumes that the property with the given key was not previously set
     /// and that it's a string or symbol.
-    pub(crate) fn accessor(
+    /// Add a accessor property to the [`ObjectTemplate`] using the given context.
+    pub(crate) fn accessor_in(
         &mut self,
+        mc: &boa_gc::MutationContext<'static, '_>,
         key: PropertyKey,
         get: bool,
         set: bool,
         attributes: Attribute,
     ) -> &mut Self {
-        // TODO: We don't support indexed keys.
         debug_assert!(!matches!(&key, PropertyKey::Index(_)));
 
         let attributes = {
@@ -97,29 +141,66 @@ impl ObjectTemplate {
             result
         };
 
-        self.shape = self.shape.insert_property_transition(TransitionKey {
-            property_key: key,
-            attributes,
-        });
+        self.shape = self.shape.insert_property_transition_in(
+            mc,
+            TransitionKey {
+                property_key: key,
+                attributes,
+            },
+        );
         self
     }
 
-    /// Create an object from the [`ObjectTemplate`]
+    /// Add a accessor property to the [`ObjectTemplate`].
     ///
-    /// The storage must match the properties provided.
-    pub(crate) fn create<T: NativeObject>(&self, data: T, storage: Vec<JsValue>) -> JsObject {
+    /// This assumes that the property with the given key was not previously set
+    /// and that it's a string or symbol.
+    pub(crate) fn accessor(
+        &mut self,
+        key: PropertyKey,
+        get: bool,
+        set: bool,
+        attributes: Attribute,
+    ) -> &mut Self {
+        self.accessor_in(
+            &unsafe { boa_gc::MutationContext::global() },
+            key,
+            get,
+            set,
+            attributes,
+        )
+    }
+
+    /// Create an object from the [`ObjectTemplate`] using the given context.
+    pub(crate) fn create_in<T: NativeObject>(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+        data: T,
+        storage: Vec<JsValue>,
+    ) -> JsObject {
         let internal_methods = data.internal_methods();
 
+        let mut properties = PropertyMap::new(
+            self.shape.clone().into(),
+            crate::object::IndexedProperties::default(),
+        );
+        properties.storage = storage;
+
         let mut object = Object {
             data: ObjectData::new(data),
             extensible: true,
-            properties: PropertyMap::new(self.shape.clone().into(), IndexedProperties::default()),
+            properties,
             private_elements: ThinVec::new(),
         };
 
-        object.properties.storage = storage;
+        JsObject::from_object_and_vtable_in(mc, object, internal_methods)
+    }
 
-        JsObject::from_object_and_vtable(object, internal_methods)
+    /// Create an object from the [`ObjectTemplate`]
+    ///
+    /// The storage must match the properties provided.
+    pub(crate) fn create<T: NativeObject>(&self, data: T, storage: Vec<JsValue>) -> JsObject {
+        self.create_in(&unsafe { boa_gc::MutationContext::global() }, data, storage)
     }
 
     /// Create an object from the [`ObjectTemplate`]
diff --git a/core/engine/src/object/shape/unique_shape.rs b/core/engine/src/object/shape/unique_shape.rs
index b050e4bf5eb..2b19a497af4 100644
--- a/core/engine/src/object/shape/unique_shape.rs
+++ b/core/engine/src/object/shape/unique_shape.rs
@@ -34,11 +34,15 @@ pub(crate) struct UniqueShape {
 }
 
 impl UniqueShape {
-    /// Create a new [`UniqueShape`].
-    pub(crate) fn new(prototype: JsPrototype, property_table: PropertyTableInner) -> Self {
+    /// Create a new [`UniqueShape`] using the given context.
+    pub(crate) fn new_in(
+        mc: &boa_gc::MutationContext<'static, '_>,
+        prototype: JsPrototype,
+        property_table: PropertyTableInner,
+    ) -> Self {
         Self {
             inner: Gc::new(
-                &unsafe { boa_gc::MutationContext::global() },
+                mc,
                 Inner {
                     property_table: RefCell::new(property_table),
                     prototype: GcRefCell::new(prototype),
@@ -47,6 +51,15 @@ impl UniqueShape {
         }
     }
 
+    /// Create a new [`UniqueShape`].
+    pub(crate) fn new(prototype: JsPrototype, property_table: PropertyTableInner) -> Self {
+        Self::new_in(
+            &unsafe { boa_gc::MutationContext::global() },
+            prototype,
+            property_table,
+        )
+    }
+
     pub(crate) fn override_internal(
         &self,
         property_table: PropertyTableInner,
@@ -254,27 +267,39 @@ pub(crate) struct WeakUniqueShape {
 
 impl WeakUniqueShape {
     /// Upgrade returns a [`UniqueShape`] pointer for the internal value if the pointer is still live,
-    /// or [`None`] if the value was already garbage collected.
+    /// or [`None`] if the value was already garbage collected, using the given context.
     #[inline]
     #[must_use]
-    pub(crate) fn upgrade(&self) -> Option<UniqueShape> {
+    pub(crate) fn upgrade_in(
+        &self,
+        mc: &boa_gc::MutationContext<'static, '_>,
+    ) -> Option<UniqueShape> {
         Some(UniqueShape {
-            inner: self
-                .inner
-                .upgrade(&unsafe { boa_gc::MutationContext::global() })?,
+            inner: self.inner.upgrade(mc)?,
         })
     }
 
+    /// Upgrade returns a [`UniqueShape`] pointer for the internal value if the pointer is still live,
+    /// or [`None`] if the value was already garbage collected.
+    #[inline]
+    #[must_use]
+    pub(crate) fn upgrade(&self) -> Option<UniqueShape> {
+        self.upgrade_in(&unsafe { boa_gc::MutationContext::global() })
+    }
+
     #[allow(dead_code)]
     pub(crate) fn is_upgradable(&self) -> bool {
         self.inner.is_upgradable()
     }
+    pub(crate) fn new_in(mc: &boa_gc::MutationContext<'static, '_>, value: &UniqueShape) -> Self {
+        WeakUniqueShape {
+            inner: WeakGc::new(mc, &value.inner),
+        }
+    }
 }
 
 impl From<&UniqueShape> for WeakUniqueShape {
     fn from(value: &UniqueShape) -> Self {
-        WeakUniqueShape {
-            inner: WeakGc::new(&unsafe { boa_gc::MutationContext::global() }, &value.inner),
-        }
+        Self::new_in(&unsafe { boa_gc::MutationContext::global() }, value)
     }
 }
diff --git a/core/engine/src/realm.rs b/core/engine/src/realm.rs
index c133ce823eb..a1d0ec1c8b1 100644
--- a/core/engine/src/realm.rs
+++ b/core/engine/src/realm.rs
@@ -77,8 +77,12 @@ struct Inner {
 impl Realm {
     /// Create a new [`Realm`].
     #[inline]
-    pub fn create(hooks: &dyn HostHooks, root_shape: &RootShape) -> JsResult<Self> {
-        let intrinsics = Intrinsics::uninit(root_shape).ok_or_else(|| {
+    pub fn create(
+        hooks: &dyn HostHooks,
+        root_shape: &RootShape,
+        mc: &boa_gc::MutationContext<'static, '_>,
+    ) -> JsResult<Self> {
+        let intrinsics = Intrinsics::uninit(root_shape, mc).ok_or_else(|| {
             JsNativeError::typ().with_message("failed to create the realm intrinsics")
         })?;
 
@@ -86,15 +90,12 @@ impl Realm {
         let global_this = hooks
             .create_global_this(&intrinsics)
             .unwrap_or_else(|| global_object.clone());
-        let environment = Gc::new(
-            &unsafe { boa_gc::MutationContext::global() },
-            DeclarativeEnvironment::global(),
-        );
+        let environment = Gc::new(mc, DeclarativeEnvironment::global());
         let scope = Scope::new_global();
 
         let realm = Self {
             inner: Gc::new(
-                &unsafe { boa_gc::MutationContext::global() },
+                mc,
                 Inner {
                     intrinsics,
                     environment,
diff --git a/core/engine/src/script.rs b/core/engine/src/script.rs
index ef9823a32cf..373129572b9 100644
--- a/core/engine/src/script.rs
+++ b/core/engine/src/script.rs
@@ -137,6 +137,7 @@ impl Script {
 
             let spanned_source_text = SpannedSourceText::new_source_only(self.get_source());
 
+            let mc = context.gc_collector();
             let mut compiler = ByteCompiler::new(
                 js_string!("<main>"),
                 source.strict(),
@@ -146,9 +147,14 @@ impl Script {
                 false,
                 false,
                 context.interner_mut(),
+                &mc,
                 false,
                 spanned_source_text,
-                self.path().map(Path::to_owned).into(),
+                self.inner
+                    .path
+                    .as_deref()
+                    .map(std::path::Path::to_path_buf)
+                    .into(),
             );
 
             #[cfg(feature = "annex-b")]
diff --git a/core/engine/src/vm/mod.rs b/core/engine/src/vm/mod.rs
index 48d957adfaf..cc4ee8247b7 100644
--- a/core/engine/src/vm/mod.rs
+++ b/core/engine/src/vm/mod.rs
@@ -404,13 +404,10 @@ impl ActiveRunnable {
 
 impl Vm {
     /// Creates a new virtual machine.
-    pub(crate) fn new(realm: Realm) -> Self {
+    pub(crate) fn new(realm: Realm, mc: &boa_gc::MutationContext<'static, '_>) -> Self {
         let mut frames = Vec::with_capacity(16);
         frames.push(CallFrame::new(
-            Gc::new(
-                &unsafe { boa_gc::MutationContext::global() },
-                CodeBlock::new(JsString::default(), 0, true),
-            ),
+            Gc::new(mc, CodeBlock::new(JsString::default(), 0, true)),
             None,
             EnvironmentStack::new(),
             realm,
diff --git a/core/engine/src/vm/opcode/push/environment.rs b/core/engine/src/vm/opcode/push/environment.rs
index 0d8b34ef974..a1eb7a76926 100644
--- a/core/engine/src/vm/opcode/push/environment.rs
+++ b/core/engine/src/vm/opcode/push/environment.rs
@@ -18,13 +18,12 @@ impl PushScope {
     #[inline(always)]
     pub(crate) fn operation(index: IndexOperand, context: &mut Context) {
         let scope = context.vm.frame().code_block().constant_scope(index.into());
+        let mc = context.gc_collector();
         let frame = context.vm.frame_mut();
         let global = frame.realm.environment();
         frame
             .environments
-            .push_lexical(scope.num_bindings_non_local(), global, unsafe {
-                boa_gc::MutationContext::global()
-            });
+            .push_lexical(scope.num_bindings_non_local(), global, mc);
     }
 }
 
diff --git a/core/gc/src/context.rs b/core/gc/src/context.rs
index 81624d8aee5..b3857952074 100644
--- a/core/gc/src/context.rs
+++ b/core/gc/src/context.rs
@@ -12,6 +12,13 @@ impl Default for GcContext {
     }
 }
 
+#[cfg(feature = "oscars_backend")]
+struct SyncWrapper(MutationContext<'static, 'static>);
+#[cfg(feature = "oscars_backend")]
+unsafe impl Sync for SyncWrapper {}
+#[cfg(feature = "oscars_backend")]
+unsafe impl Send for SyncWrapper {}
+
 #[cfg(feature = "oscars_backend")]
 impl GcContext {
     #[must_use]
@@ -20,17 +27,15 @@ impl GcContext {
     }
 
     pub fn alloc<T: crate::Trace + crate::Finalize + 'static>(&self, value: T) -> Gc<'static, T> {
-        // As a bridge, we use the global MutationContext until explicit
-        // context threading is natively supported by the oscars backend.
         let mc = MutationContext::global();
         Gc::new(&mc, value)
     }
 
     #[must_use]
-    pub fn gc_collector(&self) -> &MutationContext<'static, 'static> {
-        // Just return a dummy global mutation context
-        // This is safe for the bridge phase.
-        unimplemented!("Not supported natively without closure yet, use MutationContext::global()")
+    pub fn gc_collector(&self) -> &'static MutationContext<'static, 'static> {
+        static DUMMY: std::sync::LazyLock<SyncWrapper> =
+            std::sync::LazyLock::new(|| SyncWrapper(MutationContext::global()));
+        &DUMMY.0
     }
 }
 
@@ -45,6 +50,13 @@ impl Default for GcContext {
     }
 }
 
+#[cfg(not(feature = "oscars_backend"))]
+struct SyncWrapperDefault(crate::MutationContext<'static, 'static>);
+#[cfg(not(feature = "oscars_backend"))]
+unsafe impl Sync for SyncWrapperDefault {}
+#[cfg(not(feature = "oscars_backend"))]
+unsafe impl Send for SyncWrapperDefault {}
+
 #[cfg(not(feature = "oscars_backend"))]
 impl GcContext {
     #[must_use]
@@ -58,10 +70,9 @@ impl GcContext {
     }
 
     #[must_use]
-    pub fn gc_collector(&self) -> &crate::MutationContext<'static, 'static> {
-        // Just return a dummy global mutation context
-        static DUMMY: crate::MutationContext<'static, 'static> =
-            unsafe { crate::MutationContext::global() };
-        &DUMMY
+    pub fn gc_collector(&self) -> &'static crate::MutationContext<'static, 'static> {
+        static DUMMY: SyncWrapperDefault =
+            SyncWrapperDefault(unsafe { crate::MutationContext::global() });
+        &DUMMY.0
     }
 }

From 26b7baef8a83772b4857825a66296d0e1208ec30 Mon Sep 17 00:00:00 2001
From: shruti2522 <shruti.apc01@gmail.com>
Date: Mon, 17 Aug 2026 23:00:52 +0000
Subject: [PATCH 06/19] Integrate mark sweep backend and eliminate global GC
 state

---
 core/engine/src/builtins/eval/mod.rs          |  8 +-
 .../src/builtins/finalization_registry/mod.rs |  2 +-
 core/engine/src/builtins/function/mod.rs      | 16 ++--
 core/engine/src/builtins/iterable/mod.rs      |  6 --
 core/engine/src/builtins/uri/mod.rs           |  6 --
 core/engine/src/context/mod.rs                | 13 ++--
 core/engine/src/environments/runtime/mod.rs   | 73 +++++++++++--------
 core/engine/src/module/source.rs              |  4 +-
 core/engine/src/symbol.rs                     |  3 +-
 .../src/value/conversions/serde_json.rs       |  6 +-
 core/engine/src/vm/inline_cache/tests.rs      | 16 ++--
 core/engine/src/vm/opcode/call/mod.rs         |  6 +-
 core/engine/src/vm/opcode/push/environment.rs |  3 +-
 core/gc/Cargo.toml                            |  2 +-
 14 files changed, 83 insertions(+), 81 deletions(-)

diff --git a/core/engine/src/builtins/eval/mod.rs b/core/engine/src/builtins/eval/mod.rs
index 764c73cbf6e..ab101972742 100644
--- a/core/engine/src/builtins/eval/mod.rs
+++ b/core/engine/src/builtins/eval/mod.rs
@@ -350,11 +350,9 @@ impl Eval {
         {
             let frame = context.vm.frame_mut();
             let global = frame.realm.environment();
-            frame.environments.push_lexical(
-                lexical_scope.num_bindings_non_local(),
-                &global,
-                &unsafe { boa_gc::MutationContext::global() },
-            );
+            frame
+                .environments
+                .push_lexical(lexical_scope.num_bindings_non_local(), &global, mc);
         }
 
         context
diff --git a/core/engine/src/builtins/finalization_registry/mod.rs b/core/engine/src/builtins/finalization_registry/mod.rs
index 76899e0256a..c96c51a8e6c 100644
--- a/core/engine/src/builtins/finalization_registry/mod.rs
+++ b/core/engine/src/builtins/finalization_registry/mod.rs
@@ -172,7 +172,7 @@ impl BuiltInConstructor for FinalizationRegistry {
                 };
 
                 let Some(registry) = weak_registry
-                    .upgrade(&unsafe { boa_gc::MutationContext::global() })
+                    .upgrade(context.borrow().gc_collector())
                     .map(JsObject::from_inner)
                 else {
                     return Ok(JsValue::undefined());
diff --git a/core/engine/src/builtins/function/mod.rs b/core/engine/src/builtins/function/mod.rs
index 800de70a02a..0e0034ea960 100644
--- a/core/engine/src/builtins/function/mod.rs
+++ b/core/engine/src/builtins/function/mod.rs
@@ -1076,11 +1076,10 @@ pub(crate) fn function_call(
     let has_function_scope = context.vm.frame().code_block().has_function_scope();
 
     if has_binding_identifier {
+        let mc = context.gc_collector();
         let frame = context.vm.frame_mut();
         let global = frame.realm.environment();
-        let index = frame
-            .environments
-            .push_lexical(1, &global, &unsafe { boa_gc::MutationContext::global() });
+        let index = frame.environments.push_lexical(1, &global, mc);
         frame.environments.put_lexical_value(
             BindingLocatorScope::Stack(index),
             0,
@@ -1092,13 +1091,14 @@ pub(crate) fn function_call(
 
     if has_function_scope {
         let scope = context.vm.frame().code_block().constant_scope(last_env);
+        let mc = context.gc_collector();
         let frame = context.vm.frame_mut();
         let global = frame.realm.environment();
         frame.environments.push_function(
             scope,
             FunctionSlots::new(this, function_object.clone(), None),
             &global,
-            &unsafe { boa_gc::MutationContext::global() },
+            mc,
         );
     }
 
@@ -1188,11 +1188,10 @@ fn function_construct(
     let has_function_scope = context.vm.frame().code_block().has_function_scope();
 
     if has_binding_identifier {
+        let mc = context.gc_collector();
         let frame = context.vm.frame_mut();
         let global = frame.realm.environment();
-        let index = frame
-            .environments
-            .push_lexical(1, &global, &unsafe { boa_gc::MutationContext::global() });
+        let index = frame.environments.push_lexical(1, &global, mc);
         frame.environments.put_lexical_value(
             BindingLocatorScope::Stack(index),
             0,
@@ -1204,6 +1203,7 @@ fn function_construct(
 
     if has_function_scope {
         let scope = context.vm.frame().code_block().constant_scope(last_env);
+        let mc = context.gc_collector();
         let frame = context.vm.frame_mut();
         let global = frame.realm.environment();
         frame.environments.push_function(
@@ -1221,7 +1221,7 @@ fn function_construct(
                 ),
             ),
             &global,
-            &unsafe { boa_gc::MutationContext::global() },
+            mc,
         );
     }
 
diff --git a/core/engine/src/builtins/iterable/mod.rs b/core/engine/src/builtins/iterable/mod.rs
index 032bae56384..de4efa4a54b 100644
--- a/core/engine/src/builtins/iterable/mod.rs
+++ b/core/engine/src/builtins/iterable/mod.rs
@@ -89,12 +89,6 @@ pub struct IteratorPrototypes {
     wrap_for_valid_iterator: JsObject,
 }
 
-impl Default for IteratorPrototypes {
-    fn default() -> Self {
-        Self::uninit_in(&unsafe { boa_gc::MutationContext::global() })
-    }
-}
-
 impl IteratorPrototypes {
     pub(crate) fn uninit_in(mc: &boa_gc::MutationContext<'static, '_>) -> Self {
         Self {
diff --git a/core/engine/src/builtins/uri/mod.rs b/core/engine/src/builtins/uri/mod.rs
index 58d8ff73be2..b55e351cd3d 100644
--- a/core/engine/src/builtins/uri/mod.rs
+++ b/core/engine/src/builtins/uri/mod.rs
@@ -47,12 +47,6 @@ pub struct UriFunctions {
     encode_uri_component: JsFunction,
 }
 
-impl Default for UriFunctions {
-    fn default() -> Self {
-        Self::uninit_in(&unsafe { boa_gc::MutationContext::global() })
-    }
-}
-
 impl UriFunctions {
     pub(crate) fn uninit_in(mc: &boa_gc::MutationContext<'static, '_>) -> Self {
         Self {
diff --git a/core/engine/src/context/mod.rs b/core/engine/src/context/mod.rs
index a84ebd8fa41..a0117b5348a 100644
--- a/core/engine/src/context/mod.rs
+++ b/core/engine/src/context/mod.rs
@@ -548,9 +548,11 @@ impl Context {
 
     /// Create a new Realm with the default global bindings.
     pub fn create_realm(&mut self) -> JsResult<Realm> {
-        let realm = Realm::create(self.host_hooks.as_ref(), &self.root_shape, &unsafe {
-            boa_gc::MutationContext::global()
-        })?;
+        let realm = Realm::create(
+            self.host_hooks.as_ref(),
+            &self.root_shape,
+            self.gc_collector(),
+        )?;
 
         let old_realm = self.enter_realm(realm);
 
@@ -1224,7 +1226,8 @@ impl ContextBuilder {
             CANNOT_BLOCK_COUNTER.set(CANNOT_BLOCK_COUNTER.get() + 1);
         }
 
-        let mc = unsafe { boa_gc::MutationContext::global() };
+        let gc = boa_gc::GcContext::new();
+        let mc = gc.gc_collector();
         let root_shape = RootShape::new(&mc);
 
         let host_hooks = self.host_hooks.unwrap_or(Rc::new(DefaultHooks));
@@ -1279,7 +1282,7 @@ impl ContextBuilder {
             optimizer_options: OptimizerOptions::OPTIMIZE_ALL,
             root_shape,
             parser_identifier: 0,
-            gc: boa_gc::GcContext::new(),
+            gc,
             can_block: self.can_block,
             data: HostDefined::default(),
         };
diff --git a/core/engine/src/environments/runtime/mod.rs b/core/engine/src/environments/runtime/mod.rs
index 4e47a4f79ff..bdcc1bea321 100644
--- a/core/engine/src/environments/runtime/mod.rs
+++ b/core/engine/src/environments/runtime/mod.rs
@@ -207,8 +207,12 @@ impl EnvironmentStack {
     }
 
     /// Push a new object environment on the environments stack.
-    pub(crate) fn push_object(&mut self, object: JsObject) {
-        self.push_env(Environment::Object(object));
+    pub(crate) fn push_object(
+        &mut self,
+        object: JsObject,
+        mc: &boa_gc::MutationContext<'static, '_>,
+    ) {
+        self.push_env(Environment::Object(object), mc);
     }
 
     /// Push a lexical environment on the environments stack and return it's index.
@@ -222,14 +226,17 @@ impl EnvironmentStack {
 
         let index = self.depth;
 
-        self.push_env(Environment::Declarative(Gc::new(
-            &gc,
-            DeclarativeEnvironment::new(
-                DeclarativeEnvironmentKind::Lexical(LexicalEnvironment::new(bindings_count)),
-                poisoned,
-                with,
-            ),
-        )));
+        self.push_env(
+            Environment::Declarative(Gc::new(
+                &gc,
+                DeclarativeEnvironment::new(
+                    DeclarativeEnvironmentKind::Lexical(LexicalEnvironment::new(bindings_count)),
+                    poisoned,
+                    with,
+                ),
+            )),
+            gc,
+        );
 
         index
     }
@@ -246,31 +253,37 @@ impl EnvironmentStack {
 
         let (poisoned, with) = self.compute_poisoned_with(global);
 
-        self.push_env(Environment::Declarative(Gc::new(
+        self.push_env(
+            Environment::Declarative(Gc::new(
+                gc,
+                DeclarativeEnvironment::new(
+                    DeclarativeEnvironmentKind::Function(FunctionEnvironment::new(
+                        num_bindings,
+                        function_slots,
+                        scope,
+                    )),
+                    poisoned,
+                    with,
+                ),
+            )),
             gc,
-            DeclarativeEnvironment::new(
-                DeclarativeEnvironmentKind::Function(FunctionEnvironment::new(
-                    num_bindings,
-                    function_slots,
-                    scope,
-                )),
-                poisoned,
-                with,
-            ),
-        )));
+        );
     }
 
     /// Push a module environment on the environments stack.
     pub(crate) fn push_module(&mut self, scope: Scope, gc: &boa_gc::MutationContext<'static, '_>) {
         let num_bindings = scope.num_bindings_non_local();
-        self.push_env(Environment::Declarative(Gc::new(
+        self.push_env(
+            Environment::Declarative(Gc::new(
+                gc,
+                DeclarativeEnvironment::new(
+                    DeclarativeEnvironmentKind::Module(ModuleEnvironment::new(num_bindings, scope)),
+                    false,
+                    false,
+                ),
+            )),
             gc,
-            DeclarativeEnvironment::new(
-                DeclarativeEnvironmentKind::Module(ModuleEnvironment::new(num_bindings, scope)),
-                false,
-                false,
-            ),
-        )));
+        );
     }
 
     /// Pop environment from the environments stack.
@@ -416,9 +429,9 @@ impl EnvironmentStack {
     // ---- Private helpers ----
 
     /// Push an environment onto the chain.
-    fn push_env(&mut self, env: Environment) {
+    fn push_env(&mut self, env: Environment, mc: &boa_gc::MutationContext<'static, '_>) {
         self.tip = Some(Gc::new(
-            &unsafe { boa_gc::MutationContext::global() },
+            mc,
             EnvironmentNode {
                 env,
                 parent: self.tip.take(),
diff --git a/core/engine/src/module/source.rs b/core/engine/src/module/source.rs
index 26adadc14d7..def683d8a99 100644
--- a/core/engine/src/module/source.rs
+++ b/core/engine/src/module/source.rs
@@ -1838,9 +1838,7 @@ impl SourceTextModule {
 
         // 8. Let moduleContext be a new ECMAScript code execution context.
         let mut envs = EnvironmentStack::new();
-        envs.push_module(source.scope().clone(), &unsafe {
-            boa_gc::MutationContext::global()
-        });
+        envs.push_module(source.scope().clone(), unsafe { context.gc_collector() });
         drop(status);
 
         // 9. Set the Function of moduleContext to null.
diff --git a/core/engine/src/symbol.rs b/core/engine/src/symbol.rs
index b78fbdc69a9..9ee38e35157 100644
--- a/core/engine/src/symbol.rs
+++ b/core/engine/src/symbol.rs
@@ -420,8 +420,7 @@ mod tests {
         let mut context = Context::default();
         let symbol1 = JsSymbol::new(None).unwrap();
         let symbol2 = JsSymbol::new(None).unwrap();
-        let test_obj =
-            JsObject::from_proto_and_data(&unsafe { boa_gc::MutationContext::global() }, None, ());
+        let test_obj = JsObject::from_proto_and_data(context.gc_collector(), None, ());
         test_obj
             .set(symbol1, js_str!("Can't see me"), false, &mut context)
             .unwrap();
diff --git a/core/engine/src/value/conversions/serde_json.rs b/core/engine/src/value/conversions/serde_json.rs
index bbeeded9ef9..bbebbdd355c 100644
--- a/core/engine/src/value/conversions/serde_json.rs
+++ b/core/engine/src/value/conversions/serde_json.rs
@@ -308,7 +308,7 @@ mod tests {
     #[test]
     fn to_json_cyclic() {
         let mut context = Context::default();
-        let obj = JsObject::with_null_proto(&unsafe { boa_gc::MutationContext::global() });
+        let obj = JsObject::with_null_proto(context.gc_collector());
         obj.create_data_property(js_string!("a"), obj.clone(), &mut context)
             .expect("should create data property");
 
@@ -339,7 +339,7 @@ mod tests {
             //     "outer_c": [2, undefined, 3, { "inner_a": undefined }]
             // }
 
-            let inner = JsObject::with_null_proto(&unsafe { boa_gc::MutationContext::global() });
+            let inner = JsObject::with_null_proto(context.gc_collector());
             inner
                 .create_data_property(js_string!("inner_a"), JsValue::undefined(), &mut context)
                 .expect("should add property");
@@ -352,7 +352,7 @@ mod tests {
             array.push(3, &mut context).expect("should push");
             array.push(inner, &mut context).expect("should push");
 
-            let outer = JsObject::with_null_proto(&unsafe { boa_gc::MutationContext::global() });
+            let outer = JsObject::with_null_proto(context.gc_collector());
             outer
                 .create_data_property(js_string!("outer_a"), JsValue::new(1), &mut context)
                 .expect("should add property");
diff --git a/core/engine/src/vm/inline_cache/tests.rs b/core/engine/src/vm/inline_cache/tests.rs
index 0342bc07d62..d8e266eaf96 100644
--- a/core/engine/src/vm/inline_cache/tests.rs
+++ b/core/engine/src/vm/inline_cache/tests.rs
@@ -18,7 +18,7 @@ fn get_own_property_internal_method() {
     let context = &mut Context::default();
 
     let o = context.intrinsics().templates().ordinary_object().create(
-        &unsafe { boa_gc::MutationContext::global() },
+        context.gc_collector(),
         OrdinaryObject,
         Vec::default(),
     );
@@ -63,7 +63,7 @@ fn get_internal_method() {
     let context = &mut Context::default();
 
     let o = context.intrinsics().templates().ordinary_object().create(
-        &unsafe { boa_gc::MutationContext::global() },
+        context.gc_collector(),
         OrdinaryObject,
         Vec::default(),
     );
@@ -108,7 +108,7 @@ fn get_internal_method_in_prototype() {
     let context = &mut Context::default();
 
     let o = context.intrinsics().templates().ordinary_object().create(
-        &unsafe { boa_gc::MutationContext::global() },
+        context.gc_collector(),
         OrdinaryObject,
         Vec::default(),
     );
@@ -156,7 +156,7 @@ fn define_own_property_internal_method_non_existent_property() {
     let context = &mut Context::default();
 
     let o = context.intrinsics().templates().ordinary_object().create(
-        &unsafe { boa_gc::MutationContext::global() },
+        context.gc_collector(),
         OrdinaryObject,
         Vec::default(),
     );
@@ -210,7 +210,7 @@ fn define_own_property_internal_method_existing_property_property() {
     let context = &mut Context::default();
 
     let o = context.intrinsics().templates().ordinary_object().create(
-        &unsafe { boa_gc::MutationContext::global() },
+        context.gc_collector(),
         OrdinaryObject,
         Vec::default(),
     );
@@ -276,7 +276,7 @@ fn set_internal_method() {
     let context = &mut Context::default();
 
     let o = context.intrinsics().templates().ordinary_object().create(
-        &unsafe { boa_gc::MutationContext::global() },
+        context.gc_collector(),
         OrdinaryObject,
         Vec::default(),
     );
@@ -343,7 +343,7 @@ fn set_property_by_name_set_inline_cache_on_property_load() -> JsResult<()> {
     assert_eq!(
         code.ic[0].entries.borrow()[0]
             .shape
-            .upgrade(&unsafe { boa_gc::MutationContext::global() })
+            .upgrade(context.gc_collector())
             .unwrap()
             .to_addr_usize(),
         o_shape.to_addr_usize()
@@ -372,7 +372,7 @@ fn get_property_by_name_set_inline_cache_on_property_load() -> JsResult<()> {
     assert_eq!(
         code.ic[0].entries.borrow()[0]
             .shape
-            .upgrade(&unsafe { boa_gc::MutationContext::global() })
+            .upgrade(context.gc_collector())
             .unwrap()
             .to_addr_usize(),
         o_shape.to_addr_usize()
diff --git a/core/engine/src/vm/opcode/call/mod.rs b/core/engine/src/vm/opcode/call/mod.rs
index 410c826fb86..c71e8003a4a 100644
--- a/core/engine/src/vm/opcode/call/mod.rs
+++ b/core/engine/src/vm/opcode/call/mod.rs
@@ -448,9 +448,10 @@ async fn load_dyn_import(
 
     // 4. Let rejectedClosure be a new Abstract Closure with parameters (reason) that captures promiseCapability and performs the following steps when called:
     // 5. Let onRejected be CreateBuiltinFunction(rejectedClosure, 1, "", « »).
+    let mc = context.borrow().gc_collector();
     let on_rejected = FunctionObjectBuilder::new(
         context.borrow().realm(),
-        context.borrow_mut().gc_collector(),
+        &mc,
         NativeFunction::from_copy_closure_with_captures(
             |_, args, cap, context| {
                 //     a. Perform ! Call(promiseCapability.[[Reject]], undefined, « reason »).
@@ -468,9 +469,10 @@ async fn load_dyn_import(
 
     // 6. Let linkAndEvaluateClosure be a new Abstract Closure with no parameters that captures module, promiseCapability, and onRejected and performs the following steps when called:
     // 7. Let linkAndEvaluate be CreateBuiltinFunction(linkAndEvaluateClosure, 0, "", « »).
+    let mc = context.borrow().gc_collector();
     let link_evaluate = FunctionObjectBuilder::new(
         context.borrow().realm(),
-        context.borrow_mut().gc_collector(),
+        &mc,
         NativeFunction::from_copy_closure_with_captures(
             |_, _, (module, cap, on_rejected), context| {
                 // a. Let link be Completion(module.Link()).
diff --git a/core/engine/src/vm/opcode/push/environment.rs b/core/engine/src/vm/opcode/push/environment.rs
index a1eb7a76926..3149097b51d 100644
--- a/core/engine/src/vm/opcode/push/environment.rs
+++ b/core/engine/src/vm/opcode/push/environment.rs
@@ -45,7 +45,8 @@ impl PushObjectEnvironment {
     pub(crate) fn operation(value: RegisterOperand, context: &mut Context) -> JsResult<()> {
         let object = context.vm.get_register(value.into()).clone();
         let object = object.to_object(context)?;
-        context.vm.frame_mut().environments.push_object(object);
+        let mc = context.gc_collector();
+        context.vm.frame_mut().environments.push_object(object, mc);
         Ok(())
     }
 }
diff --git a/core/gc/Cargo.toml b/core/gc/Cargo.toml
index 10637fe4c36..030298d6d33 100644
--- a/core/gc/Cargo.toml
+++ b/core/gc/Cargo.toml
@@ -21,7 +21,7 @@ boa_string = ["dep:boa_string"]
 either = ["dep:either", "oscars?/either"]
 # Enable default implementations of trace and finalize for the arrayvec crate
 arrayvec = ["dep:arrayvec", "oscars?/arrayvec"]
-default = []
+default = ["oscars_backend"]
 boa_gc_backend = []
 oscars_backend = ["dep:oscars", "dep:typeid", "oscars?/std", "boa_string?/oscars_backend"]
 

From 516419e83eada6c11225726f79884834e54d4c01 Mon Sep 17 00:00:00 2001
From: shruti2522 <shruti.apc01@gmail.com>
Date: Tue, 18 Aug 2026 20:02:38 +0000
Subject: [PATCH 07/19] Fix test262 test suite failures for oscars integration

---
 .github/workflows/test262.yml                 |   1 -
 core/engine/src/builtins/array/from_async.rs  |   2 +
 .../src/builtins/async_generator/mod.rs       |   2 +
 core/engine/src/builtins/function/tests.rs    |   1 +
 core/engine/src/builtins/intl/collator/mod.rs |   1 +
 .../src/builtins/intl/date_time_format/mod.rs |   1 +
 .../src/builtins/intl/number_format/mod.rs    |   1 +
 .../iterable/async_from_sync_iterator.rs      |  20 +-
 .../builtins/iterable/iterator_constructor.rs |   5 +-
 .../iterable/iterator_helper/concat.rs        |   7 +-
 .../builtins/iterable/iterator_helper/drop.rs |   8 +-
 .../iterable/iterator_helper/filter.rs        |   8 +-
 .../iterable/iterator_helper/flat_map.rs      |   8 +-
 .../builtins/iterable/iterator_helper/map.rs  |   8 +-
 .../builtins/iterable/iterator_helper/take.rs |   8 +-
 .../builtins/iterable/iterator_prototype.rs   |  29 ++-
 core/engine/src/builtins/object/mod.rs        |   1 +
 core/engine/src/builtins/promise/mod.rs       |  13 +
 core/engine/src/builtins/proxy/mod.rs         |   3 +
 .../src/interop/into_js_function_impls.rs     |  24 +-
 core/engine/src/module/mod.rs                 |  44 ++--
 core/engine/src/module/source.rs              |   2 +
 core/engine/src/module/synthetic.rs           |  25 +-
 .../src/native_function/continuation.rs       |  16 +-
 core/engine/src/native_function/mod.rs        |  30 ++-
 core/engine/src/object/builtins/jsfunction.rs |  12 -
 core/engine/src/object/builtins/jspromise.rs  |   4 +
 .../src/object/builtins/jstypedarray.rs       |   1 +
 .../engine/src/object/internal_methods/mod.rs |  11 +-
 .../src/object/internal_methods/string.rs     |   1 +
 core/engine/src/value/mod.rs                  |   6 +-
 core/engine/src/vm/opcode/await/mod.rs        |   2 +
 core/engine/src/vm/opcode/call/mod.rs         |   3 +
 core/engine/src/vm/tests.rs                   |   2 +-
 core/gc/src/context.rs                        |  30 ++-
 core/gc/src/lib.rs                            |   6 +-
 core/macros/src/module.rs                     |   2 +-
 core/runtime/src/console/mod.rs               | 230 ++++++++++--------
 core/runtime/src/console/tests.rs             |  23 ++
 core/runtime/src/fetch/headers_iterator.rs    |   6 +-
 core/runtime/src/process/mod.rs               |   6 +-
 core/runtime/src/test262.rs                   |  16 +-
 examples/src/bin/closures.rs                  |  10 +-
 examples/src/bin/jstypedarray.rs              |   6 +-
 examples/src/bin/modules.rs                   |   2 +
 examples/src/bin/smol_event_loop.rs           |   2 +-
 examples/src/bin/synthetic.rs                 |   1 +
 examples/src/bin/tokio_event_loop.rs          |   2 +-
 tests/tester/src/exec/mod.rs                  |   5 +-
 49 files changed, 411 insertions(+), 246 deletions(-)

diff --git a/.github/workflows/test262.yml b/.github/workflows/test262.yml
index a8671fc37d0..d569e061ac5 100644
--- a/.github/workflows/test262.yml
+++ b/.github/workflows/test262.yml
@@ -16,7 +16,6 @@ concurrency:
 
 jobs:
   run_test262:
-    if: ${{ github.base_ref != 'dev/oscars-gc' }}
     name: Run the test262 test suite
     runs-on: ubuntu-latest
     timeout-minutes: 60
diff --git a/core/engine/src/builtins/array/from_async.rs b/core/engine/src/builtins/array/from_async.rs
index 43c8dbe8c36..cecf5fa0071 100644
--- a/core/engine/src/builtins/array/from_async.rs
+++ b/core/engine/src/builtins/array/from_async.rs
@@ -124,6 +124,7 @@ impl Array {
                         // Coroutine yielded. We need to allocate it for a future execution.
                         JsPromise::resolve(value, context)?.await_native(
                             NativeCoroutine::from_copy_closure_with_captures(
+                                context.gc_collector(),
                                 from_array_like,
                                 coroutine_state,
                             ),
@@ -174,6 +175,7 @@ impl Array {
                 CoroutineState::Continue(value) => {
                     JsPromise::resolve(value, context)?.await_native(
                         NativeCoroutine::from_copy_closure_with_captures(
+                            context.gc_collector(),
                             from_async_iterator,
                             coroutine_state,
                         ),
diff --git a/core/engine/src/builtins/async_generator/mod.rs b/core/engine/src/builtins/async_generator/mod.rs
index 298fc9f29c1..c662e5edc80 100644
--- a/core/engine/src/builtins/async_generator/mod.rs
+++ b/core/engine/src/builtins/async_generator/mod.rs
@@ -582,6 +582,7 @@ impl AsyncGenerator {
             context.realm(),
             context.gc_collector(),
             NativeFunction::from_copy_closure_with_captures(
+                context.gc_collector(),
                 |_this, args, generator, context| {
                     // a. Assert: generator.[[AsyncGeneratorState]] is draining-queue.
                     assert_eq!(
@@ -614,6 +615,7 @@ impl AsyncGenerator {
             context.realm(),
             context.gc_collector(),
             NativeFunction::from_copy_closure_with_captures(
+                context.gc_collector(),
                 |_this, args, generator, context| {
                     // a. Assert: generator.[[AsyncGeneratorState]] is draining-queue.
                     assert_eq!(
diff --git a/core/engine/src/builtins/function/tests.rs b/core/engine/src/builtins/function/tests.rs
index bb63f86efe7..da2a49dbbfe 100644
--- a/core/engine/src/builtins/function/tests.rs
+++ b/core/engine/src/builtins/function/tests.rs
@@ -150,6 +150,7 @@ fn closure_capture_clone() {
                 ctx.realm(),
                 ctx.gc_collector(),
                 NativeFunction::from_copy_closure_with_captures(
+                    ctx.gc_collector(),
                     |_, _, captures, context| {
                         let (string, object) = &captures;
 
diff --git a/core/engine/src/builtins/intl/collator/mod.rs b/core/engine/src/builtins/intl/collator/mod.rs
index bdf8ceea4be..d0c0f11072e 100644
--- a/core/engine/src/builtins/intl/collator/mod.rs
+++ b/core/engine/src/builtins/intl/collator/mod.rs
@@ -359,6 +359,7 @@ impl Collator {
                 // 10.3.3.1. Collator Compare Functions
                 // https://tc39.es/ecma402/#sec-collator-compare-functions
                 NativeFunction::from_copy_closure_with_captures(
+                    context.gc_collector(),
                     |_, args, collator, context| {
                         // 1. Let collator be F.[[Collator]].
                         // 2. Assert: Type(collator) is Object and collator has an [[InitializedCollator]] internal slot.
diff --git a/core/engine/src/builtins/intl/date_time_format/mod.rs b/core/engine/src/builtins/intl/date_time_format/mod.rs
index 0100ad0ab41..10a0abba1c3 100644
--- a/core/engine/src/builtins/intl/date_time_format/mod.rs
+++ b/core/engine/src/builtins/intl/date_time_format/mod.rs
@@ -262,6 +262,7 @@ impl DateTimeFormat {
                 context.realm(),
                 context.gc_collector(),
                 NativeFunction::from_copy_closure_with_captures(
+                    context.gc_collector(),
                     |_, args, dtf, context| {
                         // 1. Let dtf be F.[[DateTimeFormat]].
                         // 2. Assert: dtf is an Object and dtf has an [[InitializedDateTimeFormat]] internal slot.
diff --git a/core/engine/src/builtins/intl/number_format/mod.rs b/core/engine/src/builtins/intl/number_format/mod.rs
index d8253b0b581..1ea97697ea7 100644
--- a/core/engine/src/builtins/intl/number_format/mod.rs
+++ b/core/engine/src/builtins/intl/number_format/mod.rs
@@ -610,6 +610,7 @@ impl NumberFormat {
                 // Number Format Functions
                 // <https://tc39.es/ecma402/#sec-number-format-functions>
                 NativeFunction::from_copy_closure_with_captures(
+                    context.gc_collector(),
                     |_, args, nf, context| {
                         // 1. Let nf be F.[[NumberFormat]].
                         // 2. Assert: Type(nf) is Object and nf has an [[InitializedNumberFormat]] internal slot.
diff --git a/core/engine/src/builtins/iterable/async_from_sync_iterator.rs b/core/engine/src/builtins/iterable/async_from_sync_iterator.rs
index d1c2bbd4e6d..64cee86d4aa 100644
--- a/core/engine/src/builtins/iterable/async_from_sync_iterator.rs
+++ b/core/engine/src/builtins/iterable/async_from_sync_iterator.rs
@@ -364,14 +364,17 @@ impl AsyncFromSyncIterator {
         let on_fulfilled = FunctionObjectBuilder::new(
             context.realm(),
             context.gc_collector(),
-            NativeFunction::from_copy_closure(move |_this, args, context| {
-                // a. Return CreateIterResultObject(value, done).
-                Ok(create_iter_result_object(
-                    args.get_or_undefined(0).clone(),
-                    done,
-                    context,
-                ))
-            }),
+            NativeFunction::from_copy_closure(
+                context.gc_collector(),
+                move |_this, args, context| {
+                    // a. Return CreateIterResultObject(value, done).
+                    Ok(create_iter_result_object(
+                        args.get_or_undefined(0).clone(),
+                        done,
+                        context,
+                    ))
+                },
+            ),
         )
         .name(js_string!())
         .length(1)
@@ -397,6 +400,7 @@ impl AsyncFromSyncIterator {
                     context.realm(),
                     context.gc_collector(),
                     NativeFunction::from_copy_closure_with_captures(
+                        context.gc_collector(),
                         |_this, args, iter, context| {
                             // i. Return ? IteratorClose(syncIteratorRecord, ThrowCompletion(error)).
                             iter.close(
diff --git a/core/engine/src/builtins/iterable/iterator_constructor.rs b/core/engine/src/builtins/iterable/iterator_constructor.rs
index 0d29a8e20f7..9c77ae10a88 100644
--- a/core/engine/src/builtins/iterable/iterator_constructor.rs
+++ b/core/engine/src/builtins/iterable/iterator_constructor.rs
@@ -192,7 +192,10 @@ impl IteratorConstructor {
         //    (implemented via IteratorHelperOp::Concat in execute_next)
         // 4-5. Let result be CreateIteratorFromClosure(closure, "Iterator Helper", ...)
         //      with [[UnderlyingIterators]] set to a new empty List.
-        let helper = IteratorHelper::create(iterator_helper::Concat::new(iterables), context);
+        let helper = IteratorHelper::create(
+            iterator_helper::Concat::new(context.gc_collector(), iterables),
+            context,
+        );
 
         // 6. Return result.
         Ok(helper.into())
diff --git a/core/engine/src/builtins/iterable/iterator_helper/concat.rs b/core/engine/src/builtins/iterable/iterator_helper/concat.rs
index cbda860728a..5526971b744 100644
--- a/core/engine/src/builtins/iterable/iterator_helper/concat.rs
+++ b/core/engine/src/builtins/iterable/iterator_helper/concat.rs
@@ -43,11 +43,14 @@ impl Concat {
         clippy::new_ret_no_self,
         reason = "slightly cleaner to have this be a `new` method"
     )]
-    pub(crate) fn new(iterables: VecDeque<IterableRecord>) -> NativeCoroutine {
+    pub(crate) fn new(
+        mc: &boa_gc::MutationContext<'_, '_>,
+        iterables: VecDeque<IterableRecord>,
+    ) -> NativeCoroutine {
         // 3. Let closure be a new Abstract Closure with no parameters that captures
         //    iterables and performs the following steps when called:
         NativeCoroutine::from_copy_closure_with_captures(
-            // a. For each Record iterable of iterables, do
+            mc, // a. For each Record iterable of iterables, do
             |completion, state, context| {
                 let st = state.take();
                 match &st {
diff --git a/core/engine/src/builtins/iterable/iterator_helper/drop.rs b/core/engine/src/builtins/iterable/iterator_helper/drop.rs
index ffc4326c6b8..a12a263b9f3 100644
--- a/core/engine/src/builtins/iterable/iterator_helper/drop.rs
+++ b/core/engine/src/builtins/iterable/iterator_helper/drop.rs
@@ -31,12 +31,16 @@ impl Drop {
         clippy::new_ret_no_self,
         reason = "slightly cleaner to have this be a `new` method"
     )]
-    pub(crate) fn new(iterated: IteratorRecord, limit: Option<u64>) -> NativeCoroutine {
+    pub(crate) fn new(
+        mc: &boa_gc::MutationContext<'_, '_>,
+        iterated: IteratorRecord,
+        limit: Option<u64>,
+    ) -> NativeCoroutine {
         // 10. Let closure be a new Abstract Closure with no parameters that
         //     captures iterated and integerLimit and performs the following steps
         //     when called:
         NativeCoroutine::from_copy_closure_with_captures(
-            // a. Let remaining be integerLimit.
+            mc, // a. Let remaining be integerLimit.
             // c. Repeat,
             |completion, state, context| {
                 let st = state.take();
diff --git a/core/engine/src/builtins/iterable/iterator_helper/filter.rs b/core/engine/src/builtins/iterable/iterator_helper/filter.rs
index 93e74bc9204..57d1aaf73ba 100644
--- a/core/engine/src/builtins/iterable/iterator_helper/filter.rs
+++ b/core/engine/src/builtins/iterable/iterator_helper/filter.rs
@@ -31,11 +31,15 @@ impl Filter {
         clippy::new_ret_no_self,
         reason = "slightly cleaner to have this be a `new` method"
     )]
-    pub(crate) fn new(iterated: IteratorRecord, predicate: JsFunction) -> NativeCoroutine {
+    pub(crate) fn new(
+        mc: &boa_gc::MutationContext<'_, '_>,
+        iterated: IteratorRecord,
+        predicate: JsFunction,
+    ) -> NativeCoroutine {
         // 6. Let closure be a new Abstract Closure with no parameters that captures
         //    iterated and predicate and performs the following steps when called:
         NativeCoroutine::from_copy_closure_with_captures(
-            // a. Let counter be 0.
+            mc, // a. Let counter be 0.
             // b. Repeat,
             |completion, state, context| {
                 let st = state.take();
diff --git a/core/engine/src/builtins/iterable/iterator_helper/flat_map.rs b/core/engine/src/builtins/iterable/iterator_helper/flat_map.rs
index 96529387de9..f41cde0f8e8 100644
--- a/core/engine/src/builtins/iterable/iterator_helper/flat_map.rs
+++ b/core/engine/src/builtins/iterable/iterator_helper/flat_map.rs
@@ -39,11 +39,15 @@ impl FlatMap {
         clippy::new_ret_no_self,
         reason = "slightly cleaner to have this be a `new` method"
     )]
-    pub(crate) fn new(iterated: IteratorRecord, mapper: JsFunction) -> NativeCoroutine {
+    pub(crate) fn new(
+        mc: &boa_gc::MutationContext<'_, '_>,
+        iterated: IteratorRecord,
+        mapper: JsFunction,
+    ) -> NativeCoroutine {
         // 6. Let closure be a new Abstract Closure with no parameters that captures
         //    iterated and mapper and performs the following steps when called:
         NativeCoroutine::from_copy_closure_with_captures(
-            // a. Let counter be 0.
+            mc, // a. Let counter be 0.
             // b. Repeat,
             |completion, state, context| {
                 let st = state.take();
diff --git a/core/engine/src/builtins/iterable/iterator_helper/map.rs b/core/engine/src/builtins/iterable/iterator_helper/map.rs
index 2621696a614..f0879407722 100644
--- a/core/engine/src/builtins/iterable/iterator_helper/map.rs
+++ b/core/engine/src/builtins/iterable/iterator_helper/map.rs
@@ -31,11 +31,15 @@ impl Map {
         clippy::new_ret_no_self,
         reason = "slightly cleaner to have this be a `new` method"
     )]
-    pub(crate) fn new(iterated: IteratorRecord, mapper: JsFunction) -> NativeCoroutine {
+    pub(crate) fn new(
+        mc: &boa_gc::MutationContext<'_, '_>,
+        iterated: IteratorRecord,
+        mapper: JsFunction,
+    ) -> NativeCoroutine {
         // 6. Let closure be a new Abstract Closure with no parameters that captures
         //    iterated and mapper and performs the following steps when called:
         NativeCoroutine::from_copy_closure_with_captures(
-            // a. Let counter be 0.
+            mc, // a. Let counter be 0.
             // b. Repeat,
             |completion, state, context| {
                 let st = state.take();
diff --git a/core/engine/src/builtins/iterable/iterator_helper/take.rs b/core/engine/src/builtins/iterable/iterator_helper/take.rs
index 91e353bd4d4..b1feee3b533 100644
--- a/core/engine/src/builtins/iterable/iterator_helper/take.rs
+++ b/core/engine/src/builtins/iterable/iterator_helper/take.rs
@@ -29,12 +29,16 @@ impl Take {
         clippy::new_ret_no_self,
         reason = "slightly cleaner to have this be a `new` method"
     )]
-    pub(crate) fn new(iterated: IteratorRecord, limit: Option<u64>) -> NativeCoroutine {
+    pub(crate) fn new(
+        mc: &boa_gc::MutationContext<'_, '_>,
+        iterated: IteratorRecord,
+        limit: Option<u64>,
+    ) -> NativeCoroutine {
         // 10. Let closure be a new Abstract Closure with no parameters that
         //     captures iterated and integerLimit and performs the following steps
         //     when called:
         NativeCoroutine::from_copy_closure_with_captures(
-            // a. Let remaining be integerLimit.
+            mc, // a. Let remaining be integerLimit.
             // b. Repeat,
             |completion, state, context| {
                 let st = state.take();
diff --git a/core/engine/src/builtins/iterable/iterator_prototype.rs b/core/engine/src/builtins/iterable/iterator_prototype.rs
index f244ae1c6f3..abe398f4f73 100644
--- a/core/engine/src/builtins/iterable/iterator_prototype.rs
+++ b/core/engine/src/builtins/iterable/iterator_prototype.rs
@@ -235,7 +235,10 @@ impl Iterator {
         let iterated = get_iterator_direct(iterated.iterator(), context)?;
 
         // 6-8 are deferred to `IteratorHelper::create` and `Map::new`.
-        let result = IteratorHelper::create(iterator_helper::Map::new(iterated, mapper), context);
+        let result = IteratorHelper::create(
+            iterator_helper::Map::new(context.gc_collector(), iterated, mapper),
+            context,
+        );
 
         // 9. Return result.
         Ok(result.into())
@@ -274,8 +277,10 @@ impl Iterator {
         let iterated = get_iterator_direct(iterated.iterator(), context)?;
 
         // 6-8 are deferred to `IteratorHelper::create` and `Filter::new`.
-        let result =
-            IteratorHelper::create(iterator_helper::Filter::new(iterated, predicate), context);
+        let result = IteratorHelper::create(
+            iterator_helper::Filter::new(context.gc_collector(), iterated, predicate),
+            context,
+        );
 
         // 9. Return result.
         Ok(result.into())
@@ -335,8 +340,10 @@ impl Iterator {
         let iterated = get_iterator_direct(iterated.iterator(), context)?;
 
         // 10-12 are deferred to `IteratorHelper::create` and `Take::new`.
-        let result =
-            IteratorHelper::create(iterator_helper::Take::new(iterated, integer_limit), context);
+        let result = IteratorHelper::create(
+            iterator_helper::Take::new(context.gc_collector(), iterated, integer_limit),
+            context,
+        );
 
         // 13. Return result.
         Ok(result.into())
@@ -395,8 +402,10 @@ impl Iterator {
         let iterated = get_iterator_direct(iterated.iterator(), context)?;
 
         // 10-12 are deferred to `IteratorHelper::create` and `Drop::new`.
-        let result =
-            IteratorHelper::create(iterator_helper::Drop::new(iterated, integer_limit), context);
+        let result = IteratorHelper::create(
+            iterator_helper::Drop::new(context.gc_collector(), iterated, integer_limit),
+            context,
+        );
 
         // 13. Return result.
         Ok(result.into())
@@ -435,8 +444,10 @@ impl Iterator {
         let iterated = get_iterator_direct(iterated.iterator(), context)?;
 
         // 6-8 are deferred to `IteratorHelper::create` and `FlatMap::new`.
-        let helper =
-            IteratorHelper::create(iterator_helper::FlatMap::new(iterated, mapper), context);
+        let helper = IteratorHelper::create(
+            iterator_helper::FlatMap::new(context.gc_collector(), iterated, mapper),
+            context,
+        );
 
         // 9. Return result.
         Ok(helper.into())
diff --git a/core/engine/src/builtins/object/mod.rs b/core/engine/src/builtins/object/mod.rs
index 8872a4c2815..49dad929215 100644
--- a/core/engine/src/builtins/object/mod.rs
+++ b/core/engine/src/builtins/object/mod.rs
@@ -1309,6 +1309,7 @@ impl OrdinaryObject {
             context.realm(),
             context.gc_collector(),
             NativeFunction::from_copy_closure_with_captures(
+                context.gc_collector(),
                 |_, args, obj, context| {
                     let key = args.get_or_undefined(0);
                     let value = args.get_or_undefined(1);
diff --git a/core/engine/src/builtins/promise/mod.rs b/core/engine/src/builtins/promise/mod.rs
index 6d7d2c1c76c..15a0f6c3ad8 100644
--- a/core/engine/src/builtins/promise/mod.rs
+++ b/core/engine/src/builtins/promise/mod.rs
@@ -254,6 +254,7 @@ impl PromiseCapability {
             context.realm(),
             context.gc_collector(),
             NativeFunction::from_copy_closure_with_captures(
+                context.gc_collector(),
                 |_this, args: &[JsValue], captures, _| {
                     let mut promise_capability = captures.borrow_mut();
                     // a. If promiseCapability.[[Resolve]] is not undefined, throw a TypeError exception.
@@ -685,6 +686,7 @@ impl Promise {
                 context.realm(),
                 context.gc_collector(),
                 NativeFunction::from_copy_closure_with_captures(
+                    context.gc_collector(),
                     |_, args, captures, context| {
                         // https://tc39.es/ecma262/#sec-promise.all-resolve-element-functions
 
@@ -904,6 +906,7 @@ impl Promise {
                 context.realm(),
                 context.gc_collector(),
                 NativeFunction::from_copy_closure_with_captures(
+                    context.gc_collector(),
                     |_, args, captures, context| {
                         // https://tc39.es/ecma262/#sec-promise.allsettled-resolve-element-functions
 
@@ -998,6 +1001,7 @@ impl Promise {
                 context.realm(),
                 context.gc_collector(),
                 NativeFunction::from_copy_closure_with_captures(
+                    context.gc_collector(),
                     |_, args, captures, context| {
                         // https://tc39.es/ecma262/#sec-promise.allsettled-reject-element-functions
 
@@ -1286,6 +1290,7 @@ impl Promise {
                     context.realm(),
                     context.gc_collector(),
                     NativeFunction::from_copy_closure_with_captures(
+                        context.gc_collector(),
                         |_, args, captures, context| {
                             // 1. If alreadyCalled.[[Value]] is true, return undefined.
                             if captures.already_called.get() {
@@ -1372,6 +1377,7 @@ impl Promise {
                         context.realm(),
                         context.gc_collector(),
                         NativeFunction::from_copy_closure_with_captures(
+                            context.gc_collector(),
                             |_, args, captures, context| {
                                 // 1. If alreadyCalled.[[Value]] is true, return undefined.
                                 if captures.already_called.get() {
@@ -1595,6 +1601,7 @@ impl Promise {
                 context.realm(),
                 context.gc_collector(),
                 NativeFunction::from_copy_closure_with_captures(
+                    context.gc_collector(),
                     |_, args, captures, context| {
                         // https://tc39.es/ecma262/#sec-promise.any-reject-element-functions
 
@@ -2029,6 +2036,7 @@ impl Promise {
             context.realm(),
             context.gc_collector(),
             NativeFunction::from_copy_closure_with_captures(
+                context.gc_collector(),
                 |_this, args, captures, context| {
                     /// Capture object for the abstract `returnValue` closure.
                     #[derive(Debug, Trace, Finalize)]
@@ -2051,6 +2059,7 @@ impl Promise {
                         context.realm(),
                         context.gc_collector(),
                         NativeFunction::from_copy_closure_with_captures(
+                            context.gc_collector(),
                             |_this, _args, captures, _context| {
                                 // 1. Return value.
                                 Ok(captures.value.clone())
@@ -2082,6 +2091,7 @@ impl Promise {
             context.realm(),
             context.gc_collector(),
             NativeFunction::from_copy_closure_with_captures(
+                context.gc_collector(),
                 |_this, args, captures, context| {
                     /// Capture object for the abstract `throwReason` closure.
                     #[derive(Debug, Trace, Finalize)]
@@ -2104,6 +2114,7 @@ impl Promise {
                         context.realm(),
                         context.gc_collector(),
                         NativeFunction::from_copy_closure_with_captures(
+                            context.gc_collector(),
                             |_this, _args, captures, _context| {
                                 // 1. Return ThrowCompletion(reason).
                                 Err(JsError::from_opaque(captures.reason.clone()))
@@ -2479,6 +2490,7 @@ impl Promise {
             context.realm(),
             context.gc_collector(),
             NativeFunction::from_copy_closure_with_captures(
+                context.gc_collector(),
                 |_this, args, captures, context| {
                     // https://tc39.es/ecma262/#sec-promise-resolve-functions
 
@@ -2577,6 +2589,7 @@ impl Promise {
             context.realm(),
             context.gc_collector(),
             NativeFunction::from_copy_closure_with_captures(
+                context.gc_collector(),
                 |_this, args, captures, context| {
                     // https://tc39.es/ecma262/#sec-promise-reject-functions
 
diff --git a/core/engine/src/builtins/proxy/mod.rs b/core/engine/src/builtins/proxy/mod.rs
index 4b7c4d5e27c..046e15ff75b 100644
--- a/core/engine/src/builtins/proxy/mod.rs
+++ b/core/engine/src/builtins/proxy/mod.rs
@@ -197,6 +197,7 @@ impl Proxy {
         // 4. Set revoker.[[RevocableProxy]] to p.
 
         NativeFunction::from_copy_closure_with_captures(
+            context.gc_collector(),
             |_, _, revocable_proxy, _| {
                 // a. Let F be the active function object.
                 // b. Let p be F.[[RevocableProxy]].
@@ -547,6 +548,7 @@ pub(crate) fn proxy_exotic_get_own_property(
         extensible_target,
         result_desc.clone(),
         target_desc.clone(),
+        context.gc_collector(),
     ) {
         return Err(JsNativeError::typ()
             .with_message("Proxy trap returned unexpected property")
@@ -662,6 +664,7 @@ pub(crate) fn proxy_exotic_define_own_property(
                 extensible_target,
                 desc.clone(),
                 Some(target_desc.clone()),
+                context.gc_collector(),
             ) {
                 return Err(JsNativeError::typ()
                     .with_message("Proxy trap set property to unexpected value")
diff --git a/core/engine/src/interop/into_js_function_impls.rs b/core/engine/src/interop/into_js_function_impls.rs
index 9a4cb19195f..51954f837f2 100644
--- a/core/engine/src/interop/into_js_function_impls.rs
+++ b/core/engine/src/interop/into_js_function_impls.rs
@@ -51,7 +51,7 @@ macro_rules! impl_into_js_function {
             unsafe fn into_js_function_unsafe(self, _context: &mut Context) -> NativeFunction {
                 let s = RefCell::new(self);
                 unsafe {
-                    NativeFunction::from_closure(move |this, args, ctx| {
+                    NativeFunction::from_closure(_context.gc_collector(), move |this, args, ctx| {
                         let rest = args;
                         $(
                             let ($id, rest) = $t::try_from_js_argument(this, rest, ctx)?;
@@ -77,7 +77,7 @@ macro_rules! impl_into_js_function {
             unsafe fn into_js_function_unsafe(self, _context: &mut Context) -> NativeFunction {
                 let s = RefCell::new(self);
                 unsafe {
-                    NativeFunction::from_closure(move |this, args, ctx| {
+                    NativeFunction::from_closure(_context.gc_collector(), move |this, args, ctx| {
                         let rest = args;
                         $(
                             let ($id, rest) = $t::try_from_js_argument(this, rest, ctx)?;
@@ -103,7 +103,7 @@ macro_rules! impl_into_js_function {
             unsafe fn into_js_function_unsafe(self, _context: &mut Context) -> NativeFunction {
                 let s = RefCell::new(self);
                 unsafe {
-                    NativeFunction::from_closure(move |this, args, ctx| {
+                    NativeFunction::from_closure(_context.gc_collector(), move |this, args, ctx| {
                         let rest = args;
                         $(
                             let ($id, rest) = $t::try_from_js_argument(this, rest, ctx)?;
@@ -125,7 +125,7 @@ macro_rules! impl_into_js_function {
             unsafe fn into_js_function_unsafe(self, _context: &mut Context) -> NativeFunction {
                 let s = RefCell::new(self);
                 unsafe {
-                    NativeFunction::from_closure(move |this, args, ctx| {
+                    NativeFunction::from_closure(_context.gc_collector(), move |this, args, ctx| {
                         let rest = args;
                         $(
                             let ($id, rest) = $t::try_from_js_argument(this, rest, ctx)?;
@@ -145,9 +145,9 @@ macro_rules! impl_into_js_function {
             T: Fn($($t,)*) -> R + 'static + Copy,
         {
             #[allow(unused_variables)]
-            fn into_js_function_copied(self, _context: &mut Context) -> NativeFunction {
+            fn into_js_function_copied(self, context: &mut Context) -> NativeFunction {
                 let s = self;
-                NativeFunction::from_copy_closure(move |this, args, ctx| {
+                NativeFunction::from_copy_closure(context.gc_collector(), move |this, args, ctx| {
                     let rest = args;
                     $(
                         let ($id, rest) = $t::try_from_js_argument(this, rest, ctx)?;
@@ -165,9 +165,9 @@ macro_rules! impl_into_js_function {
             T: Fn($($t,)* JsRest<'_>) -> R + 'static + Copy,
         {
             #[allow(unused_variables)]
-            fn into_js_function_copied(self, _context: &mut Context) -> NativeFunction {
+            fn into_js_function_copied(self, context: &mut Context) -> NativeFunction {
                 let s = self;
-                NativeFunction::from_copy_closure(move |this, args, ctx| {
+                NativeFunction::from_copy_closure(context.gc_collector(), move |this, args, ctx| {
                     let rest = args;
                     $(
                         let ($id, rest) = $t::try_from_js_argument(this, rest, ctx)?;
@@ -185,9 +185,9 @@ macro_rules! impl_into_js_function {
             T: Fn($($t,)* &mut Context) -> R + 'static + Copy,
         {
             #[allow(unused_variables)]
-            fn into_js_function_copied(self, _context: &mut Context) -> NativeFunction {
+            fn into_js_function_copied(self, context: &mut Context) -> NativeFunction {
                 let s = self;
-                NativeFunction::from_copy_closure(move |this, args, ctx| {
+                NativeFunction::from_copy_closure(context.gc_collector(), move |this, args, ctx| {
                     let rest = args;
                     $(
                         let ($id, rest) = $t::try_from_js_argument(this, rest, ctx)?;
@@ -205,9 +205,9 @@ macro_rules! impl_into_js_function {
             T: Fn($($t,)* JsRest<'_>, &mut Context) -> R + 'static + Copy,
         {
             #[allow(unused_variables)]
-            fn into_js_function_copied(self, _context: &mut Context) -> NativeFunction {
+            fn into_js_function_copied(self, context: &mut Context) -> NativeFunction {
                 let s = self;
-                NativeFunction::from_copy_closure(move |this, args, ctx| {
+                NativeFunction::from_copy_closure(context.gc_collector(), move |this, args, ctx| {
                     let rest = args;
                     $(
                         let ($id, rest) = $t::try_from_js_argument(this, rest, ctx)?;
diff --git a/core/engine/src/module/mod.rs b/core/engine/src/module/mod.rs
index 01c9d8f7a45..e1cb1f29dfa 100644
--- a/core/engine/src/module/mod.rs
+++ b/core/engine/src/module/mod.rs
@@ -330,13 +330,16 @@ impl Module {
     pub fn from_value_as_default(value: JsValue, context: &mut Context) -> Self {
         Module::synthetic(
             &[js_string!("default")],
-            SyntheticModuleInitializer::from_copy_closure_with_captures(
-                move |m, value, _ctx| {
-                    m.set_export(&js_string!("default"), value.clone())?;
-                    Ok(())
-                },
-                value,
-            ),
+            unsafe {
+                SyntheticModuleInitializer::from_closure_with_captures(
+                    context.gc_collector(),
+                    move |m, value, _ctx| {
+                        m.set_export(&js_string!("default"), value.clone())?;
+                        Ok(())
+                    },
+                    value,
+                )
+            },
             None,
             None,
             context,
@@ -652,6 +655,7 @@ impl Module {
             .then(
                 Some(
                     NativeFunction::from_copy_closure_with_captures(
+                        context.gc_collector(),
                         |_, _, module, context| {
                             module.link(context)?;
                             Ok(JsValue::undefined())
@@ -667,6 +671,7 @@ impl Module {
             .then(
                 Some(
                     NativeFunction::from_copy_closure_with_captures(
+                        context.gc_collector(),
                         |_, _, module, context| Ok(module.evaluate(context)?.into()),
                         self.clone(),
                     )
@@ -782,17 +787,20 @@ impl<T: IntoIterator<Item = (JsString, NativeFunction)> + Clone> IntoJsModule fo
         Module::synthetic(
             exports.as_slice(),
             unsafe {
-                SyntheticModuleInitializer::from_closure(move |module, context| {
-                    for (name, f) in names.iter().zip(fns.iter()) {
-                        module.set_export(
-                            name,
-                            f.clone()
-                                .to_js_function(context.realm(), context.gc_collector())
-                                .into(),
-                        )?;
-                    }
-                    Ok(())
-                })
+                SyntheticModuleInitializer::from_closure(
+                    context.gc_collector(),
+                    move |module, context| {
+                        for (name, f) in names.iter().zip(fns.iter()) {
+                            module.set_export(
+                                name,
+                                f.clone()
+                                    .to_js_function(context.realm(), context.gc_collector())
+                                    .into(),
+                            )?;
+                        }
+                        Ok(())
+                    },
+                )
             },
             None,
             None,
diff --git a/core/engine/src/module/source.rs b/core/engine/src/module/source.rs
index def683d8a99..25127a48d49 100644
--- a/core/engine/src/module/source.rs
+++ b/core/engine/src/module/source.rs
@@ -1479,6 +1479,7 @@ impl SourceTextModule {
             context.realm(),
             context.gc_collector(),
             NativeFunction::from_copy_closure_with_captures(
+                context.gc_collector(),
                 |_, _, module, context| {
                     //     a. Perform AsyncModuleExecutionFulfilled(module).
                     async_module_execution_fulfilled(module, context)?;
@@ -1496,6 +1497,7 @@ impl SourceTextModule {
             context.realm(),
             context.gc_collector(),
             NativeFunction::from_copy_closure_with_captures(
+                context.gc_collector(),
                 |_, args, module, context| {
                     let error = JsError::from_opaque(args.get_or_undefined(0).clone());
                     // a. Perform AsyncModuleExecutionRejected(module, error).
diff --git a/core/engine/src/module/synthetic.rs b/core/engine/src/module/synthetic.rs
index f0bbde545fa..ad178da7cfc 100644
--- a/core/engine/src/module/synthetic.rs
+++ b/core/engine/src/module/synthetic.rs
@@ -65,22 +65,26 @@ impl std::fmt::Debug for SyntheticModuleInitializer {
 
 impl SyntheticModuleInitializer {
     /// Creates a `SyntheticModuleInitializer` from a [`Copy`] closure.
-    pub fn from_copy_closure<F>(closure: F) -> Self
+    pub fn from_copy_closure<F>(mc: &boa_gc::MutationContext<'_, '_>, closure: F) -> Self
     where
         F: Fn(&SyntheticModule, &mut Context) -> JsResult<()> + Copy + 'static,
     {
         // SAFETY: The `Copy` bound ensures there are no traceable types inside the closure.
-        unsafe { Self::from_closure(closure) }
+        unsafe { Self::from_closure(mc, closure) }
     }
 
     /// Creates a `SyntheticModuleInitializer` from a [`Copy`] closure and a list of traceable captures.
-    pub fn from_copy_closure_with_captures<F, T>(closure: F, captures: T) -> Self
+    pub fn from_copy_closure_with_captures<F, T>(
+        mc: &boa_gc::MutationContext<'_, '_>,
+        closure: F,
+        captures: T,
+    ) -> Self
     where
         F: Fn(&SyntheticModule, &T, &mut Context) -> JsResult<()> + Copy + 'static,
         T: Trace + 'static,
     {
         // SAFETY: The `Copy` bound ensures there are no traceable types inside the closure.
-        unsafe { Self::from_closure_with_captures(closure, captures) }
+        unsafe { Self::from_closure_with_captures(mc, closure, captures) }
     }
 
     /// Creates a new `SyntheticModuleInitializer` from a closure.
@@ -91,13 +95,14 @@ impl SyntheticModuleInitializer {
     /// collector could cause an use after free, memory corruption or other kinds of **Undefined
     /// Behaviour**. See <https://github.com/Manishearth/rust-gc/issues/50> for a technical explanation
     /// on why that is the case.
-    pub unsafe fn from_closure<F>(closure: F) -> Self
+    pub unsafe fn from_closure<F>(mc: &boa_gc::MutationContext<'_, '_>, closure: F) -> Self
     where
         F: Fn(&SyntheticModule, &mut Context) -> JsResult<()> + 'static,
     {
         // SAFETY: The caller must ensure the invariants of the closure hold.
         unsafe {
             Self::from_closure_with_captures(
+                mc,
                 move |module, (), context| closure(module, context),
                 (),
             )
@@ -112,7 +117,11 @@ impl SyntheticModuleInitializer {
     /// collector could cause an use after free, memory corruption or other kinds of **Undefined
     /// Behaviour**. See <https://github.com/Manishearth/rust-gc/issues/50> for a technical explanation
     /// on why that is the case.
-    pub unsafe fn from_closure_with_captures<F, T>(closure: F, captures: T) -> Self
+    pub unsafe fn from_closure_with_captures<F, T>(
+        mc: &boa_gc::MutationContext<'_, '_>,
+        closure: F,
+        captures: T,
+    ) -> Self
     where
         F: Fn(&SyntheticModule, &T, &mut Context) -> JsResult<()> + 'static,
         T: Trace + 'static,
@@ -120,7 +129,7 @@ impl SyntheticModuleInitializer {
         // Hopefully, this unsafe operation will be replaced by the `CoerceUnsized` API in the
         // future: https://github.com/rust-lang/rust/issues/18598
         let ptr = Gc::into_raw(Gc::new(
-            &unsafe { boa_gc::MutationContext::global() },
+            mc,
             Callback {
                 f: closure,
                 captures,
@@ -344,7 +353,7 @@ impl SyntheticModule {
         let cb = context.alloc(finished);
 
         let mut envs = EnvironmentStack::new();
-        envs.push_module(module_scope, &unsafe { boa_gc::MutationContext::global() });
+        envs.push_module(module_scope, context.gc_collector());
 
         for locator in exports {
             //     b. Perform ! env.InitializeBinding(exportName, undefined).
diff --git a/core/engine/src/native_function/continuation.rs b/core/engine/src/native_function/continuation.rs
index abce83e1e0f..651bd9de071 100644
--- a/core/engine/src/native_function/continuation.rs
+++ b/core/engine/src/native_function/continuation.rs
@@ -83,13 +83,17 @@ impl std::fmt::Debug for NativeCoroutine {
 
 impl NativeCoroutine {
     /// Creates a `NativeCoroutine` from a `Copy` closure and a list of traceable captures.
-    pub(crate) fn from_copy_closure_with_captures<F, T>(closure: F, captures: T) -> Self
+    pub(crate) fn from_copy_closure_with_captures<F, T>(
+        mc: &boa_gc::MutationContext<'_, '_>,
+        closure: F,
+        captures: T,
+    ) -> Self
     where
         F: Fn(CompletionRecord, &T, &mut Context) -> CoroutineState + Copy + 'static,
         T: Trace + 'static,
     {
         // SAFETY: The `Copy` bound ensures there are no traceable types inside the closure.
-        unsafe { Self::from_closure_with_captures(closure, captures) }
+        unsafe { Self::from_closure_with_captures(mc, closure, captures) }
     }
 
     /// Create a new `NativeCoroutine` from a closure and a list of traceable captures.
@@ -100,7 +104,11 @@ impl NativeCoroutine {
     /// collector could cause an use after free, memory corruption or other kinds of **Undefined
     /// Behaviour**. See <https://github.com/Manishearth/rust-gc/issues/50> for a technical explanation
     /// on why that is the case.
-    pub(crate) unsafe fn from_closure_with_captures<F, T>(closure: F, captures: T) -> Self
+    pub(crate) unsafe fn from_closure_with_captures<F, T>(
+        mc: &boa_gc::MutationContext<'_, '_>,
+        closure: F,
+        captures: T,
+    ) -> Self
     where
         F: Fn(CompletionRecord, &T, &mut Context) -> CoroutineState + 'static,
         T: Trace + 'static,
@@ -108,7 +116,7 @@ impl NativeCoroutine {
         // Hopefully, this unsafe operation will be replaced by the `CoerceUnsized` API in the
         // future: https://github.com/rust-lang/rust/issues/18598
         let ptr = Gc::into_raw(Gc::new(
-            &unsafe { boa_gc::MutationContext::global() },
+            mc,
             Coroutine {
                 f: closure,
                 captures,
diff --git a/core/engine/src/native_function/mod.rs b/core/engine/src/native_function/mod.rs
index 86e9d141160..1cdc33780eb 100644
--- a/core/engine/src/native_function/mod.rs
+++ b/core/engine/src/native_function/mod.rs
@@ -191,14 +191,15 @@ impl NativeFunction {
     ///     let value = arg.to_u32(&mut context.borrow_mut())?;
     ///     Ok(JsValue::from(value * 2))
     /// }
-    /// NativeFunction::from_async_fn(test);
+    /// let mut context = Context::default();
+    /// NativeFunction::from_async_fn(context.gc_collector(), test);
     /// ```
-    pub fn from_async_fn<F>(f: F) -> Self
+    pub fn from_async_fn<F>(mc: &boa_gc::MutationContext<'_, '_>, f: F) -> Self
     where
         F: AsyncFn(&JsValue, &[JsValue], &RefCell<&mut Context>) -> JsResult<JsValue> + 'static,
         F: Copy,
     {
-        Self::from_copy_closure(move |this, args, context| {
+        Self::from_copy_closure(mc, move |this, args, context| {
             let (promise, resolvers) = JsPromise::new_pending(context);
             let this = this.clone();
             let args = args.to_vec();
@@ -224,22 +225,26 @@ impl NativeFunction {
     }
 
     /// Creates a `NativeFunction` from a `Copy` closure.
-    pub fn from_copy_closure<F>(closure: F) -> Self
+    pub fn from_copy_closure<F>(mc: &boa_gc::MutationContext<'_, '_>, closure: F) -> Self
     where
         F: Fn(&JsValue, &[JsValue], &mut Context) -> JsResult<JsValue> + Copy + 'static,
     {
         // SAFETY: The `Copy` bound ensures there are no traceable types inside the closure.
-        unsafe { Self::from_closure(closure) }
+        unsafe { Self::from_closure(mc, closure) }
     }
 
     /// Creates a `NativeFunction` from a `Copy` closure and a list of traceable captures.
-    pub fn from_copy_closure_with_captures<F, T>(closure: F, captures: T) -> Self
+    pub fn from_copy_closure_with_captures<F, T>(
+        mc: &boa_gc::MutationContext<'_, '_>,
+        closure: F,
+        captures: T,
+    ) -> Self
     where
         F: Fn(&JsValue, &[JsValue], &T, &mut Context) -> JsResult<JsValue> + Copy + 'static,
         T: Trace + 'static,
     {
         // SAFETY: The `Copy` bound ensures there are no traceable types inside the closure.
-        unsafe { Self::from_closure_with_captures(closure, captures) }
+        unsafe { Self::from_closure_with_captures(mc, closure, captures) }
     }
 
     /// Creates a new `NativeFunction` from a closure.
@@ -250,13 +255,14 @@ impl NativeFunction {
     /// collector could cause an use after free, memory corruption or other kinds of **Undefined
     /// Behaviour**. See <https://github.com/Manishearth/rust-gc/issues/50> for a technical explanation
     /// on why that is the case.
-    pub unsafe fn from_closure<F>(closure: F) -> Self
+    pub unsafe fn from_closure<F>(mc: &boa_gc::MutationContext<'_, '_>, closure: F) -> Self
     where
         F: Fn(&JsValue, &[JsValue], &mut Context) -> JsResult<JsValue> + 'static,
     {
         // SAFETY: The caller must ensure the invariants of the closure hold.
         unsafe {
             Self::from_closure_with_captures(
+                mc,
                 move |this, args, (), context| closure(this, args, context),
                 (),
             )
@@ -271,7 +277,11 @@ impl NativeFunction {
     /// collector could cause an use after free, memory corruption or other kinds of **Undefined
     /// Behaviour**. See <https://github.com/Manishearth/rust-gc/issues/50> for a technical explanation
     /// on why that is the case.
-    pub unsafe fn from_closure_with_captures<F, T>(closure: F, captures: T) -> Self
+    pub unsafe fn from_closure_with_captures<F, T>(
+        mc: &boa_gc::MutationContext<'_, '_>,
+        closure: F,
+        captures: T,
+    ) -> Self
     where
         F: Fn(&JsValue, &[JsValue], &T, &mut Context) -> JsResult<JsValue> + 'static,
         T: Trace + 'static,
@@ -279,7 +289,7 @@ impl NativeFunction {
         // Hopefully, this unsafe operation will be replaced by the `CoerceUnsized` API in the
         // future: https://github.com/rust-lang/rust/issues/18598
         let ptr = Gc::into_raw(Gc::new(
-            &unsafe { boa_gc::MutationContext::global() },
+            mc,
             Closure {
                 f: closure,
                 captures,
diff --git a/core/engine/src/object/builtins/jsfunction.rs b/core/engine/src/object/builtins/jsfunction.rs
index 8e76b155ad3..3de7d9b5a0a 100644
--- a/core/engine/src/object/builtins/jsfunction.rs
+++ b/core/engine/src/object/builtins/jsfunction.rs
@@ -141,18 +141,6 @@ impl JsFunction {
         }
     }
 
-    /// Creates a new, empty intrinsic function object with only its function internal methods set.
-    ///
-    /// Mainly used to initialize objects before a [`Context`] is available to do so.
-    ///
-    /// [`Context`]: crate::Context
-    pub(crate) fn empty_intrinsic_function(constructor: bool) -> Self {
-        Self::empty_intrinsic_function_in(
-            &unsafe { boa_gc::MutationContext::global() },
-            constructor,
-        )
-    }
-
     /// Creates a [`JsFunction`] from a [`JsObject`], or returns `None` if the object is not a function.
     ///
     /// This does not clone the fields of the function, it only does a shallow clone of the object.
diff --git a/core/engine/src/object/builtins/jspromise.rs b/core/engine/src/object/builtins/jspromise.rs
index fef2ce9811f..5c3957ef189 100644
--- a/core/engine/src/object/builtins/jspromise.rs
+++ b/core/engine/src/object/builtins/jspromise.rs
@@ -1105,6 +1105,7 @@ impl JsPromise {
             let state = state.clone();
 
             NativeFunction::from_copy_closure_with_captures(
+                context.gc_collector(),
                 move |_, args, state, _| {
                     finish(state, Ok(args.get_or_undefined(0).clone()));
                     Ok(JsValue::undefined())
@@ -1117,6 +1118,7 @@ impl JsPromise {
             let state = state.clone();
 
             NativeFunction::from_copy_closure_with_captures(
+                context.gc_collector(),
                 move |_, args, state, _| {
                     let err = JsError::from_opaque(args.get_or_undefined(0).clone());
                     finish(state, Err(err));
@@ -1245,6 +1247,7 @@ impl JsPromise {
             context.realm(),
             context.gc_collector(),
             NativeFunction::from_copy_closure_with_captures(
+                context.gc_collector(),
                 |_this, args, captures, context| {
                     // a. Let prevContext be the running execution context.
                     // b. Suspend prevContext.
@@ -1310,6 +1313,7 @@ impl JsPromise {
             context.realm(),
             context.gc_collector(),
             NativeFunction::from_copy_closure_with_captures(
+                context.gc_collector(),
                 |_this, args, captures, context| {
                     // a. Let prevContext be the running execution context.
                     // b. Suspend prevContext.
diff --git a/core/engine/src/object/builtins/jstypedarray.rs b/core/engine/src/object/builtins/jstypedarray.rs
index 817391d4ca0..4cc23bdfb69 100644
--- a/core/engine/src/object/builtins/jstypedarray.rs
+++ b/core/engine/src/object/builtins/jstypedarray.rs
@@ -687,6 +687,7 @@ impl JsTypedArray {
     ///     context.realm(),
     ///     context.gc_collector(),
     ///     NativeFunction::from_copy_closure_with_captures(
+    ///         context.gc_collector(),
     ///         |_, args, captures, inner_context| {
     ///             let element = args
     ///                 .first()
diff --git a/core/engine/src/object/internal_methods/mod.rs b/core/engine/src/object/internal_methods/mod.rs
index e2c11a4f662..d7223e1da7e 100644
--- a/core/engine/src/object/internal_methods/mod.rs
+++ b/core/engine/src/object/internal_methods/mod.rs
@@ -1010,18 +1010,11 @@ pub(crate) fn is_compatible_property_descriptor(
     extensible: bool,
     desc: PropertyDescriptor,
     current: Option<PropertyDescriptor>,
+    mc: &boa_gc::MutationContext<'_, '_>,
 ) -> bool {
     // 1. Return ValidateAndApplyPropertyDescriptor(undefined, undefined, Extensible, Desc, Current).
     let mut dummy_slot = Slot::new();
-    let dummy_mc = unsafe { boa_gc::MutationContext::global() };
-    validate_and_apply_property_descriptor(
-        None,
-        extensible,
-        desc,
-        current,
-        &mut dummy_slot,
-        &dummy_mc,
-    )
+    validate_and_apply_property_descriptor(None, extensible, desc, current, &mut dummy_slot, mc)
 }
 
 /// Abstract operation `ValidateAndApplyPropertyDescriptor`
diff --git a/core/engine/src/object/internal_methods/string.rs b/core/engine/src/object/internal_methods/string.rs
index 11a60219bd3..57f7087a103 100644
--- a/core/engine/src/object/internal_methods/string.rs
+++ b/core/engine/src/object/internal_methods/string.rs
@@ -68,6 +68,7 @@ pub(crate) fn string_exotic_define_own_property(
             extensible,
             desc,
             Some(string_desc),
+            context.gc_collector(),
         ))
     } else {
         // 4. Return ! OrdinaryDefineOwnProperty(S, P, Desc).
diff --git a/core/engine/src/value/mod.rs b/core/engine/src/value/mod.rs
index ea09d5785df..af5351f04fc 100644
--- a/core/engine/src/value/mod.rs
+++ b/core/engine/src/value/mod.rs
@@ -359,7 +359,7 @@ impl JsValue {
     /// use boa_engine::{Context, JsValue, NativeFunction};
     ///
     /// let context = &mut Context::default();
-    /// let native_fn = NativeFunction::from_copy_closure(|_, _, _| Ok(JsValue::undefined()));
+    /// let native_fn = NativeFunction::from_copy_closure(context.gc_collector(), |_, _, _| Ok(JsValue::undefined()));
     /// let js_value = JsValue::from(native_fn.to_js_function(context.realm(), context.gc_collector()));
     /// assert!(js_value.is_callable());
     ///
@@ -380,7 +380,7 @@ impl JsValue {
     /// use boa_engine::{Context, JsValue, NativeFunction};
     ///
     /// let context = &mut Context::default();
-    /// let native_fn = NativeFunction::from_copy_closure(|_, _, _| Ok(JsValue::undefined()));
+    /// let native_fn = NativeFunction::from_copy_closure(context.gc_collector(), |_, _, _| Ok(JsValue::undefined()));
     /// let js_value = JsValue::from(native_fn.to_js_function(context.realm(), context.gc_collector()));
     /// assert!(js_value.as_callable().is_some());
     ///
@@ -402,7 +402,7 @@ impl JsValue {
     /// use boa_engine::{Context, JsValue, NativeFunction};
     ///
     /// let context = &mut Context::default();
-    /// let native_fn = NativeFunction::from_copy_closure(|_, _, _| Ok(JsValue::undefined()));
+    /// let native_fn = NativeFunction::from_copy_closure(context.gc_collector(), |_, _, _| Ok(JsValue::undefined()));
     /// let js_value = JsValue::from(native_fn.to_js_function(context.realm(), context.gc_collector()));
     /// assert!(js_value.as_function().is_some());
     ///
diff --git a/core/engine/src/vm/opcode/await/mod.rs b/core/engine/src/vm/opcode/await/mod.rs
index 9c777986a80..4a4b3ba41fa 100644
--- a/core/engine/src/vm/opcode/await/mod.rs
+++ b/core/engine/src/vm/opcode/await/mod.rs
@@ -64,6 +64,7 @@ impl Await {
             context.realm(),
             context.gc_collector(),
             NativeFunction::from_copy_closure_with_captures(
+                context.gc_collector(),
                 |_this, args, captures, context| {
                     // a. Let prevContext be the running execution context.
                     // b. Suspend prevContext.
@@ -104,6 +105,7 @@ impl Await {
             context.realm(),
             context.gc_collector(),
             NativeFunction::from_copy_closure_with_captures(
+                context.gc_collector(),
                 |_this, args, captures, context| {
                     // a. Let prevContext be the running execution context.
                     // b. Suspend prevContext.
diff --git a/core/engine/src/vm/opcode/call/mod.rs b/core/engine/src/vm/opcode/call/mod.rs
index c71e8003a4a..aa1b42e3bb9 100644
--- a/core/engine/src/vm/opcode/call/mod.rs
+++ b/core/engine/src/vm/opcode/call/mod.rs
@@ -453,6 +453,7 @@ async fn load_dyn_import(
         context.borrow().realm(),
         &mc,
         NativeFunction::from_copy_closure_with_captures(
+            &mc,
             |_, args, cap, context| {
                 //     a. Perform ! Call(promiseCapability.[[Reject]], undefined, « reason »).
                 cap.reject()
@@ -474,6 +475,7 @@ async fn load_dyn_import(
         context.borrow().realm(),
         &mc,
         NativeFunction::from_copy_closure_with_captures(
+            &mc,
             |_, _, (module, cap, on_rejected), context| {
                 // a. Let link be Completion(module.Link()).
                 // b. If link is an abrupt completion, then
@@ -496,6 +498,7 @@ async fn load_dyn_import(
                     context.realm(),
                     context.gc_collector(),
                     NativeFunction::from_copy_closure_with_captures(
+                        context.gc_collector(),
                         |_, _, (module, cap), context| {
                             // i. Let namespace be GetModuleNamespace(module).
                             let namespace = module.namespace(context);
diff --git a/core/engine/src/vm/tests.rs b/core/engine/src/vm/tests.rs
index 4655d97a09f..85f6606bce0 100644
--- a/core/engine/src/vm/tests.rs
+++ b/core/engine/src/vm/tests.rs
@@ -52,7 +52,7 @@ fn position() {
         .register_global_callable(
             js_string!("check_stack"),
             2,
-            NativeFunction::from_copy_closure(|_, _, context| {
+            NativeFunction::from_copy_closure(context.gc_collector(), |_, _, context| {
                 let frame = context.stack_trace().collect::<Vec<&CallFrame>>();
 
                 assert_eq!(frame.len(), 4);
diff --git a/core/gc/src/context.rs b/core/gc/src/context.rs
index 4df8c7e3012..5cf014b83fa 100644
--- a/core/gc/src/context.rs
+++ b/core/gc/src/context.rs
@@ -12,6 +12,18 @@ impl Default for GcContext {
     }
 }
 
+#[cfg(feature = "oscars_backend")]
+thread_local! {
+    static COLLECTOR: &'static oscars::collectors::mark_sweep_branded::Collector =
+        Box::leak(Box::new(oscars::collectors::mark_sweep_branded::Collector::new()));
+
+    static DUMMY: &'static MutationContext<'static, 'static> = COLLECTOR.with(|c| {
+        Box::leak(Box::new(unsafe {
+            MutationContext::from_collector_erased(*c)
+        }))
+    });
+}
+
 #[cfg(feature = "oscars_backend")]
 impl GcContext {
     #[must_use]
@@ -20,24 +32,18 @@ impl GcContext {
     }
 
     pub fn alloc<T: crate::Trace + crate::Finalize + 'static>(&self, value: T) -> Gc<'static, T> {
-        let mc = MutationContext::global();
-        Gc::new(&mc, value)
+        let mc = self.gc_collector();
+        Gc::new(mc, value)
     }
 
     #[must_use]
     pub fn gc_collector(&self) -> &'static MutationContext<'static, 'static> {
-        thread_local! {
-            static COLLECTOR: &'static oscars::collectors::mark_sweep_branded::Collector =
-                Box::leak(Box::new(oscars::collectors::mark_sweep_branded::Collector::new()));
-
-            static DUMMY: &'static MutationContext<'static, 'static> = COLLECTOR.with(|c| {
-                Box::leak(Box::new(unsafe {
-                    oscars::collectors::mark_sweep_branded::MutationContext::from_collector_erased(*c)
-                }))
-            });
-        }
         DUMMY.with(|dummy| *dummy)
     }
+
+    pub fn force_collect(&self) {
+        COLLECTOR.with(|c| c.collect());
+    }
 }
 
 #[cfg(not(feature = "oscars_backend"))]
diff --git a/core/gc/src/lib.rs b/core/gc/src/lib.rs
index 2296038dc87..b50c2dda207 100644
--- a/core/gc/src/lib.rs
+++ b/core/gc/src/lib.rs
@@ -171,4 +171,8 @@ mod test;
 
 #[cfg(feature = "oscars_backend")]
 /// Forces a garbage collection
-pub fn force_collect() {}
+pub fn force_collect() {
+    let mc = MutationContext::global();
+    mc.collect();
+    crate::context::GcContext::new().force_collect();
+}
diff --git a/core/macros/src/module.rs b/core/macros/src/module.rs
index beb9c5cef59..046bc4fe022 100644
--- a/core/macros/src/module.rs
+++ b/core/macros/src/module.rs
@@ -272,7 +272,7 @@ fn module_impl_impl(_args: ModuleArguments, mut mod_: ItemMod) -> SpannedResult<
                 boa_engine::Module::synthetic(
                     &[ #module_exports ],
                     boa_engine::module::SyntheticModuleInitializer::from_copy_closure(
-                        |m, context| {
+                        context.gc_collector(), |m, context| {
                             #module_fn
                             Ok(())
                         }
diff --git a/core/runtime/src/console/mod.rs b/core/runtime/src/console/mod.rs
index 3aec9447708..a9dc41fd6fb 100644
--- a/core/runtime/src/console/mod.rs
+++ b/core/runtime/src/console/mod.rs
@@ -339,25 +339,27 @@ impl Console {
         L: Logger + 'static,
     {
         fn console_method<L: Logger + 'static>(
+            mc: &boa_gc::MutationContext<'_, '_>,
             f: fn(&JsValue, &[JsValue], &Console, &L, &mut Context) -> JsResult<JsValue>,
             state: Rc<RefCell<Console>>,
             logger: Rc<L>,
         ) -> NativeFunction {
             // SAFETY: `Console` doesn't contain types that need tracing.
             unsafe {
-                NativeFunction::from_closure(move |this, args, context| {
+                NativeFunction::from_closure(mc, move |this, args, context| {
                     f(this, args, &state.borrow(), &logger, context)
                 })
             }
         }
         fn console_method_mut<L: Logger + 'static>(
+            mc: &boa_gc::MutationContext<'_, '_>,
             f: fn(&JsValue, &[JsValue], &mut Console, &L, &mut Context) -> JsResult<JsValue>,
             state: Rc<RefCell<Console>>,
             logger: Rc<L>,
         ) -> NativeFunction {
             // SAFETY: `Console` doesn't contain types that need tracing.
             unsafe {
-                NativeFunction::from_closure(move |this, args, context| {
+                NativeFunction::from_closure(mc, move |this, args, context| {
                     f(this, args, &mut state.borrow_mut(), &logger, context)
                 })
             }
@@ -366,6 +368,116 @@ impl Console {
         let state = Rc::new(RefCell::new(Self::default()));
         let logger = Rc::new(logger);
 
+        let assert_fn = console_method(
+            context.gc_collector(),
+            Self::assert,
+            state.clone(),
+            logger.clone(),
+        );
+        let clear_fn = console_method_mut(
+            context.gc_collector(),
+            Self::clear,
+            state.clone(),
+            logger.clone(),
+        );
+        let debug_fn = console_method(
+            context.gc_collector(),
+            Self::debug,
+            state.clone(),
+            logger.clone(),
+        );
+        let error_fn = console_method(
+            context.gc_collector(),
+            Self::error,
+            state.clone(),
+            logger.clone(),
+        );
+        let info_fn = console_method(
+            context.gc_collector(),
+            Self::info,
+            state.clone(),
+            logger.clone(),
+        );
+        let log_fn = console_method(
+            context.gc_collector(),
+            Self::log,
+            state.clone(),
+            logger.clone(),
+        );
+        let trace_fn = console_method(
+            context.gc_collector(),
+            Self::trace,
+            state.clone(),
+            logger.clone(),
+        );
+        let warn_fn = console_method(
+            context.gc_collector(),
+            Self::warn,
+            state.clone(),
+            logger.clone(),
+        );
+        let count_fn = console_method_mut(
+            context.gc_collector(),
+            Self::count,
+            state.clone(),
+            logger.clone(),
+        );
+        let count_reset_fn = console_method_mut(
+            context.gc_collector(),
+            Self::count_reset,
+            state.clone(),
+            logger.clone(),
+        );
+        let group_fn = console_method_mut(
+            context.gc_collector(),
+            Self::group,
+            state.clone(),
+            logger.clone(),
+        );
+        let group_collapsed_fn = console_method_mut(
+            context.gc_collector(),
+            Self::group_collapsed,
+            state.clone(),
+            logger.clone(),
+        );
+        let group_end_fn = console_method_mut(
+            context.gc_collector(),
+            Self::group_end,
+            state.clone(),
+            logger.clone(),
+        );
+        let time_fn = console_method_mut(
+            context.gc_collector(),
+            Self::time,
+            state.clone(),
+            logger.clone(),
+        );
+        let time_log_fn = console_method(
+            context.gc_collector(),
+            Self::time_log,
+            state.clone(),
+            logger.clone(),
+        );
+        let time_end_fn = console_method_mut(
+            context.gc_collector(),
+            Self::time_end,
+            state.clone(),
+            logger.clone(),
+        );
+        let dir_fn = console_method(
+            context.gc_collector(),
+            Self::dir,
+            state.clone(),
+            logger.clone(),
+        );
+        let dirxml_fn = console_method(
+            context.gc_collector(),
+            Self::dir,
+            state.clone(),
+            logger.clone(),
+        );
+        let table_fn = console_method(context.gc_collector(), Self::table, state, logger.clone());
+
         ObjectInitializer::with_native_data_and_proto(
             Self::default(),
             JsObject::with_object_proto(context.gc_collector(), context.realm().intrinsics()),
@@ -376,101 +488,25 @@ impl Console {
             Self::NAME,
             Attribute::CONFIGURABLE,
         )
-        .function(
-            console_method(Self::assert, state.clone(), logger.clone()),
-            js_string!("assert"),
-            0,
-        )
-        .function(
-            console_method_mut(Self::clear, state.clone(), logger.clone()),
-            js_string!("clear"),
-            0,
-        )
-        .function(
-            console_method(Self::debug, state.clone(), logger.clone()),
-            js_string!("debug"),
-            0,
-        )
-        .function(
-            console_method(Self::error, state.clone(), logger.clone()),
-            js_string!("error"),
-            0,
-        )
-        .function(
-            console_method(Self::info, state.clone(), logger.clone()),
-            js_string!("info"),
-            0,
-        )
-        .function(
-            console_method(Self::log, state.clone(), logger.clone()),
-            js_string!("log"),
-            0,
-        )
-        .function(
-            console_method(Self::trace, state.clone(), logger.clone()),
-            js_string!("trace"),
-            0,
-        )
-        .function(
-            console_method(Self::warn, state.clone(), logger.clone()),
-            js_string!("warn"),
-            0,
-        )
-        .function(
-            console_method_mut(Self::count, state.clone(), logger.clone()),
-            js_string!("count"),
-            0,
-        )
-        .function(
-            console_method_mut(Self::count_reset, state.clone(), logger.clone()),
-            js_string!("countReset"),
-            0,
-        )
-        .function(
-            console_method_mut(Self::group, state.clone(), logger.clone()),
-            js_string!("group"),
-            0,
-        )
-        .function(
-            console_method_mut(Self::group_collapsed, state.clone(), logger.clone()),
-            js_string!("groupCollapsed"),
-            0,
-        )
-        .function(
-            console_method_mut(Self::group_end, state.clone(), logger.clone()),
-            js_string!("groupEnd"),
-            0,
-        )
-        .function(
-            console_method_mut(Self::time, state.clone(), logger.clone()),
-            js_string!("time"),
-            0,
-        )
-        .function(
-            console_method(Self::time_log, state.clone(), logger.clone()),
-            js_string!("timeLog"),
-            0,
-        )
-        .function(
-            console_method_mut(Self::time_end, state.clone(), logger.clone()),
-            js_string!("timeEnd"),
-            0,
-        )
-        .function(
-            console_method(Self::dir, state.clone(), logger.clone()),
-            js_string!("dir"),
-            0,
-        )
-        .function(
-            console_method(Self::dir, state.clone(), logger.clone()),
-            js_string!("dirxml"),
-            0,
-        )
-        .function(
-            console_method(Self::table, state, logger.clone()),
-            js_string!("table"),
-            0,
-        )
+        .function(assert_fn, js_string!("assert"), 0)
+        .function(clear_fn, js_string!("clear"), 0)
+        .function(debug_fn, js_string!("debug"), 0)
+        .function(error_fn, js_string!("error"), 0)
+        .function(info_fn, js_string!("info"), 0)
+        .function(log_fn, js_string!("log"), 0)
+        .function(trace_fn, js_string!("trace"), 0)
+        .function(warn_fn, js_string!("warn"), 0)
+        .function(count_fn, js_string!("count"), 0)
+        .function(count_reset_fn, js_string!("countReset"), 0)
+        .function(group_fn, js_string!("group"), 0)
+        .function(group_collapsed_fn, js_string!("groupCollapsed"), 0)
+        .function(group_end_fn, js_string!("groupEnd"), 0)
+        .function(time_fn, js_string!("time"), 0)
+        .function(time_log_fn, js_string!("timeLog"), 0)
+        .function(time_end_fn, js_string!("timeEnd"), 0)
+        .function(dir_fn, js_string!("dir"), 0)
+        .function(dirxml_fn, js_string!("dirxml"), 0)
+        .function(table_fn, js_string!("table"), 0)
         .build()
     }
 
diff --git a/core/runtime/src/console/tests.rs b/core/runtime/src/console/tests.rs
index 8810d7d038e..2b24100fea8 100644
--- a/core/runtime/src/console/tests.rs
+++ b/core/runtime/src/console/tests.rs
@@ -137,6 +137,29 @@ impl Logger for RecordingLogger {
     fn error(&self, msg: String, state: &ConsoleState, context: &mut Context) -> JsResult<()> {
         self.log(msg, state, context)
     }
+
+    fn table(
+        &self,
+        data: crate::console::TableData,
+        state: &ConsoleState,
+        context: &mut Context,
+    ) -> JsResult<()> {
+        let mut table = comfy_table::Table::new();
+        table.load_preset(comfy_table::presets::UTF8_FULL);
+        // Do not use Dynamic arrangement in tests to avoid wrapping based on pseudo-TTY width.
+        table.set_header(&data.col_names);
+
+        for row in &data.rows {
+            let cells: Vec<comfy_table::Cell> = data
+                .col_names
+                .iter()
+                .map(|name| comfy_table::Cell::new(row.get(name).cloned().unwrap_or_default()))
+                .collect();
+            table.add_row(cells);
+        }
+
+        self.log(table.to_string(), state, context)
+    }
 }
 
 /// Harness methods to be used in JS tests.
diff --git a/core/runtime/src/fetch/headers_iterator.rs b/core/runtime/src/fetch/headers_iterator.rs
index aa7e4116dc5..6be8da9de08 100644
--- a/core/runtime/src/fetch/headers_iterator.rs
+++ b/core/runtime/src/fetch/headers_iterator.rs
@@ -116,11 +116,7 @@ impl HeadersIterator {
             .ok_or_else(|| boa_engine::js_error!(Error: "Headers Iterator not registered"))?
             .prototype();
 
-        let headers_iterator = JsObject::from_proto_and_data(
-            &unsafe { boa_gc::MutationContext::global() },
-            proto,
-            iter,
-        );
+        let headers_iterator = JsObject::from_proto_and_data(context.gc_collector(), proto, iter);
         Ok(headers_iterator.into())
     }
 }
diff --git a/core/runtime/src/process/mod.rs b/core/runtime/src/process/mod.rs
index a9f04743aab..48b39757297 100644
--- a/core/runtime/src/process/mod.rs
+++ b/core/runtime/src/process/mod.rs
@@ -69,12 +69,13 @@ impl Process {
         P: ProcessProvider + 'static,
     {
         fn process_method<P: ProcessProvider + 'static>(
+            mc: &boa_gc::MutationContext<'_, '_>,
             f: fn(&JsValue, &[JsValue], &P, &mut Context) -> JsResult<JsValue>,
             provider: Rc<P>,
         ) -> NativeFunction {
             // SAFETY: `Process` doesn't contain types that need tracing.
             unsafe {
-                NativeFunction::from_closure(move |this, args, context| {
+                NativeFunction::from_closure(mc, move |this, args, context| {
                     f(this, args, &provider, context)
                 })
             }
@@ -87,6 +88,8 @@ impl Process {
             env.set(key, JsValue::from(value), false, context)?;
         }
 
+        let gc_collector = context.gc_collector();
+
         Ok(ObjectInitializer::new(context)
             .property(
                 JsSymbol::to_string_tag(),
@@ -100,6 +103,7 @@ impl Process {
             )
             .function(
                 process_method(
+                    gc_collector,
                     |_, _, provider, _| provider.cwd().map(JsValue::from),
                     provider.clone(),
                 ),
diff --git a/core/runtime/src/test262.rs b/core/runtime/src/test262.rs
index 34552890664..9dac56e496e 100644
--- a/core/runtime/src/test262.rs
+++ b/core/runtime/src/test262.rs
@@ -127,11 +127,7 @@ pub fn register_js262(handles: WorkerHandles, console: bool, context: &mut Conte
     js262
         .create_data_property_or_throw(
             js_string!("IsHTMLDDA"),
-            JsObject::from_proto_and_data(
-                &unsafe { boa_gc::MutationContext::global() },
-                None,
-                IsHTMLDDA,
-            ),
+            JsObject::from_proto_and_data(context.gc_collector(), None, IsHTMLDDA),
             context,
         )
         .expect("the IsHTMLDDA property must be definable");
@@ -235,7 +231,7 @@ fn agent_obj(handles: WorkerHandles, console: bool, context: &mut Context) -> Js
 
     let start = unsafe {
         let bus = bus.clone();
-        NativeFunction::from_closure(move |_, args, context| {
+        NativeFunction::from_closure(context.gc_collector(), move |_, args, context| {
             let script = args
                 .get_or_undefined(0)
                 .to_string(context)?
@@ -274,7 +270,7 @@ fn agent_obj(handles: WorkerHandles, console: bool, context: &mut Context) -> Js
 
     let broadcast = unsafe {
         // should technically also have a second numeric argument, but the test262 never uses it.
-        NativeFunction::from_closure(move |_, args, _| {
+        NativeFunction::from_closure(context.gc_collector(), move |_, args, _| {
             let buffer = args.get_or_undefined(0).as_object().ok_or_else(|| {
                 JsNativeError::typ().with_message("argument was not a shared array")
             })?;
@@ -290,7 +286,7 @@ fn agent_obj(handles: WorkerHandles, console: bool, context: &mut Context) -> Js
     };
 
     let get_report = unsafe {
-        NativeFunction::from_closure(move |_, _, _| {
+        NativeFunction::from_closure(context.gc_collector(), move |_, _, _| {
             let Ok(msg) = reports_rx.try_recv() else {
                 return Ok(JsValue::null());
             };
@@ -321,7 +317,7 @@ fn register_js262_worker(
     let rx = RefCell::new(rx);
     let receive_broadcast = unsafe {
         // should technically also have a second numeric argument, but the test262 never uses it.
-        NativeFunction::from_closure(move |_, args, context| {
+        NativeFunction::from_closure(context.gc_collector(), move |_, args, context| {
             let array = rx.borrow_mut().recv().map_err(|err| {
                 JsNativeError::typ().with_message(format!("failed to receive buffer: {err}"))
             })?;
@@ -337,7 +333,7 @@ fn register_js262_worker(
     };
 
     let report = unsafe {
-        NativeFunction::from_closure(move |_, args, context| {
+        NativeFunction::from_closure(context.gc_collector(), move |_, args, context| {
             let string = args.get_or_undefined(0).to_string(context)?.to_vec();
             tx.send(string)
                 .map_err(|e| JsNativeError::typ().with_message(e.to_string()))?;
diff --git a/examples/src/bin/closures.rs b/examples/src/bin/closures.rs
index ffeda1681bc..24d92645b4d 100644
--- a/examples/src/bin/closures.rs
+++ b/examples/src/bin/closures.rs
@@ -24,7 +24,7 @@ fn main() -> Result<(), JsError> {
         .register_global_callable(
             JsString::from("closure"),
             0,
-            NativeFunction::from_copy_closure(move |_, _, _| {
+            NativeFunction::from_copy_closure(context.gc_collector(), move |_, _, _| {
                 println!("Called `closure`");
                 // `variable` is captured from the main function.
                 println!("variable = {variable}");
@@ -72,6 +72,7 @@ fn main() -> Result<(), JsError> {
         context.realm(),
         context.gc_collector(),
         NativeFunction::from_copy_closure_with_captures(
+            context.gc_collector(),
             |_, _, captures, context| {
                 let mut captures = captures.borrow_mut();
                 let BigStruct { greeting, object } = &mut *captures;
@@ -80,15 +81,16 @@ fn main() -> Result<(), JsError> {
                 let name = object.get(js_string!("name"), context)?;
 
                 // We create a new message from our captured variable.
+                let greeting_ref: &JsString = greeting;
                 let message = js_string!(
                     &js_string!("message from `"),
                     &name.to_string(context)?,
                     &js_string!("`: "),
-                    &*greeting
+                    greeting_ref
                 );
 
                 // We can also mutate the moved data inside the closure.
-                captures.greeting = js_string!(&*greeting, &js_string!(" Hello!"));
+                captures.greeting = js_string!(greeting_ref, &js_string!(" Hello!"));
 
                 println!("{}", message.to_std_string_escaped());
                 println!();
@@ -149,7 +151,7 @@ fn main() -> Result<(), JsError> {
             // Note that it is required to use `unsafe` code, since the compiler cannot verify that the
             // types captured by the closure are not traceable.
             unsafe {
-                NativeFunction::from_closure(move |_, _, context| {
+                NativeFunction::from_closure(context.gc_collector(), move |_, _, context| {
                     println!("Called `enumerate`");
                     // `index` is captured from the main function.
                     println!("index = {}", index.get());
diff --git a/examples/src/bin/jstypedarray.rs b/examples/src/bin/jstypedarray.rs
index 0a2971c5a1f..92987af7c2f 100644
--- a/examples/src/bin/jstypedarray.rs
+++ b/examples/src/bin/jstypedarray.rs
@@ -95,15 +95,13 @@ fn main() -> JsResult<()> {
 
     // forEach
     let array = JsUint8Array::from_iter(vec![1, 2, 3, 4, 5], context)?;
-    let num_to_modify = Gc::new(
-        &unsafe { boa_gc::MutationContext::global() },
-        GcRefCell::new(0u8),
-    );
+    let num_to_modify = Gc::new(context.gc_collector(), GcRefCell::new(0u8));
 
     let js_function = FunctionObjectBuilder::new(
         context.realm(),
         context.gc_collector(),
         NativeFunction::from_copy_closure_with_captures(
+            context.gc_collector(),
             |_, args, captures, inner_context| {
                 let element = args
                     .first()
diff --git a/examples/src/bin/modules.rs b/examples/src/bin/modules.rs
index d513c6f3ccb..aefc3f2f947 100644
--- a/examples/src/bin/modules.rs
+++ b/examples/src/bin/modules.rs
@@ -55,6 +55,7 @@ fn main() -> Result<(), Box<dyn Error>> {
         .then(
             Some(
                 NativeFunction::from_copy_closure_with_captures(
+                    context.gc_collector(),
                     |_, _, module, context| {
                         // After loading, link all modules by resolving the imports
                         // and exports on the full module graph, initializing module
@@ -74,6 +75,7 @@ fn main() -> Result<(), Box<dyn Error>> {
         .then(
             Some(
                 NativeFunction::from_copy_closure_with_captures(
+                    context.gc_collector(),
                     // Finally, evaluate the root module.
                     // This returns a `JsPromise` since a module could have
                     // top-level await statements, which defers module execution to the
diff --git a/examples/src/bin/smol_event_loop.rs b/examples/src/bin/smol_event_loop.rs
index 504c39761d1..b54bf9ade1a 100644
--- a/examples/src/bin/smol_event_loop.rs
+++ b/examples/src/bin/smol_event_loop.rs
@@ -201,7 +201,7 @@ fn add_runtime(context: &mut Context) {
         .register_global_builtin_callable(
             js_string!("delay"),
             1,
-            NativeFunction::from_async_fn(delay),
+            NativeFunction::from_async_fn(context.gc_collector(), delay),
         )
         .expect("the delay builtin shouldn't exist");
 
diff --git a/examples/src/bin/synthetic.rs b/examples/src/bin/synthetic.rs
index c892c9b35de..e87fdec0679 100644
--- a/examples/src/bin/synthetic.rs
+++ b/examples/src/bin/synthetic.rs
@@ -167,6 +167,7 @@ fn create_operations_module(context: &mut Context) -> Module {
         // The initializer is evaluated every time a module imports this synthetic module,
         // so we avoid creating duplicate objects by capturing and cloning them instead.
         SyntheticModuleInitializer::from_copy_closure_with_captures(
+            context.gc_collector(),
             |module, fns, _| {
                 println!("Running initializer!");
                 module.set_export(&js_string!("sum"), fns.0.clone().into())?;
diff --git a/examples/src/bin/tokio_event_loop.rs b/examples/src/bin/tokio_event_loop.rs
index d82a1ed31af..2261cd52e58 100644
--- a/examples/src/bin/tokio_event_loop.rs
+++ b/examples/src/bin/tokio_event_loop.rs
@@ -208,7 +208,7 @@ fn add_runtime(context: &mut Context) {
         .register_global_builtin_callable(
             js_string!("delay"),
             1,
-            NativeFunction::from_async_fn(delay),
+            NativeFunction::from_async_fn(context.gc_collector(), delay),
         )
         .expect("the delay builtin shouldn't exist");
 
diff --git a/tests/tester/src/exec/mod.rs b/tests/tester/src/exec/mod.rs
index 4fbe43a7a9d..44e47688b58 100644
--- a/tests/tester/src/exec/mod.rs
+++ b/tests/tester/src/exec/mod.rs
@@ -515,6 +515,9 @@ impl Test {
             },
         );
 
+        // Force GC collection to prevent memory exhaustion when running tens of thousands of tests.
+        boa_engine::gc::force_collect();
+
         self.create_result(result, result_text, strict, verbosity)
     }
 
@@ -628,7 +631,7 @@ fn register_print_fn(context: &mut Context, async_result: AsyncResult) {
         context.gc_collector(),
         // SAFETY: `AsyncResult` has only non-traceable captures, making this safe.
         unsafe {
-            NativeFunction::from_closure(move |_, args, context| {
+            NativeFunction::from_closure(context.gc_collector(), move |_, args, context| {
                 let message = args
                     .get_or_undefined(0)
                     .to_string(context)?

From bc7d8fe6a0ba1ebd7d6a1efa35e16cf061f5916f Mon Sep 17 00:00:00 2001
From: shruti2522 <shruti.apc01@gmail.com>
Date: Thu, 20 Aug 2026 01:19:28 +0000
Subject: [PATCH 08/19] Implement exact rooting via HandleScope

---
 core/engine/src/bytecompiler/class.rs         |  12 +-
 core/engine/src/bytecompiler/function.rs      |   2 +-
 core/engine/src/context/mod.rs                |   6 +
 core/engine/src/environments/runtime/mod.rs   |   8 +-
 core/engine/src/module/synthetic.rs           |   2 +-
 .../src/native_function/continuation.rs       |   2 +-
 core/engine/src/native_function/mod.rs        |   2 +-
 core/engine/src/object/jsobject.rs            |  12 +-
 .../src/object/shape/shared_shape/mod.rs      |   2 +-
 core/engine/src/object/shape/unique_shape.rs  |   2 +-
 core/engine/src/realm.rs                      |   4 +-
 core/engine/src/value/inner/nan_boxed.rs      |   3 +
 core/engine/src/value/tests.rs                |   3 +
 core/engine/src/vm/mod.rs                     |   2 +-
 core/gc/src/context.rs                        |  10 ++
 core/gc/src/lib.rs                            |  25 ++++
 core/gc/src/pointers/gc.rs                    |   9 +-
 core/gc/src/scope.rs                          | 110 ++++++++++++++++++
 core/gc/src/scope_tracker.rs                  |  22 ++++
 19 files changed, 212 insertions(+), 26 deletions(-)
 create mode 100644 core/gc/src/scope.rs
 create mode 100644 core/gc/src/scope_tracker.rs

diff --git a/core/engine/src/bytecompiler/class.rs b/core/engine/src/bytecompiler/class.rs
index 25f8563b08c..f48d0862deb 100644
--- a/core/engine/src/bytecompiler/class.rs
+++ b/core/engine/src/bytecompiler/class.rs
@@ -157,7 +157,7 @@ impl ByteCompiler<'_> {
             class.super_ref.is_some(),
         );
 
-        let code = Gc::new(self.mc.0, compiler.finish());
+        let code = boa_gc::allocate_rooted(self.mc.0, compiler.finish());
         let index = self.push_function_to_constants(code);
 
         let class_register = self.register_allocator.alloc();
@@ -442,7 +442,7 @@ impl ByteCompiler<'_> {
 
                     field_compiler.code_block_flags |= CodeBlockFlags::IN_CLASS_FIELD_INITIALIZER;
 
-                    let code = Gc::new(self.mc.0, field_compiler.finish());
+                    let code = boa_gc::allocate_rooted(self.mc.0, field_compiler.finish());
                     let index = self.push_function_to_constants(code);
 
                     let dst = self.register_allocator.alloc();
@@ -489,7 +489,7 @@ impl ByteCompiler<'_> {
 
                     field_compiler.code_block_flags |= CodeBlockFlags::IN_CLASS_FIELD_INITIALIZER;
 
-                    let code = Gc::new(self.mc.0, field_compiler.finish());
+                    let code = boa_gc::allocate_rooted(self.mc.0, field_compiler.finish());
                     let index = self.push_function_to_constants(code);
                     let dst = self.register_allocator.alloc();
                     self.emit_get_function(&dst, index);
@@ -546,7 +546,7 @@ impl ByteCompiler<'_> {
                     field_compiler.code_block_flags |= CodeBlockFlags::IN_CLASS_FIELD_INITIALIZER;
 
                     let code = field_compiler.finish();
-                    let code = Gc::new(self.mc.0, code);
+                    let code = boa_gc::allocate_rooted(self.mc.0, code);
 
                     static_elements.push(StaticElement::StaticField {
                         code,
@@ -591,7 +591,7 @@ impl ByteCompiler<'_> {
                     field_compiler.code_block_flags |= CodeBlockFlags::IN_CLASS_FIELD_INITIALIZER;
 
                     let code = field_compiler.finish();
-                    let code = Gc::new(self.mc.0, code);
+                    let code = boa_gc::allocate_rooted(self.mc.0, code);
 
                     static_elements.push(StaticElement::StaticField {
                         code,
@@ -635,7 +635,7 @@ impl ByteCompiler<'_> {
                         );
                     }
 
-                    let code = Gc::new(self.mc.0, compiler.finish());
+                    let code = boa_gc::allocate_rooted(self.mc.0, compiler.finish());
                     static_elements.push(StaticElement::StaticBlock(code));
                 }
             }
diff --git a/core/engine/src/bytecompiler/function.rs b/core/engine/src/bytecompiler/function.rs
index 371b8ab53fc..97321284d34 100644
--- a/core/engine/src/bytecompiler/function.rs
+++ b/core/engine/src/bytecompiler/function.rs
@@ -229,6 +229,6 @@ impl FunctionCompiler {
 
         let code = compiler.finish();
 
-        Gc::new(mc, code)
+        boa_gc::allocate_rooted(mc, code)
     }
 }
diff --git a/core/engine/src/context/mod.rs b/core/engine/src/context/mod.rs
index a0117b5348a..4e252980b69 100644
--- a/core/engine/src/context/mod.rs
+++ b/core/engine/src/context/mod.rs
@@ -108,6 +108,8 @@ pub struct Context {
     pub(crate) kept_alive: Vec<JsObject>,
 
     pub gc: boa_gc::GcContext,
+    #[cfg(feature = "oscars_backend")]
+    global_scope: boa_gc::HandleScope,
 
     can_block: bool,
 
@@ -1227,6 +1229,8 @@ impl ContextBuilder {
         }
 
         let gc = boa_gc::GcContext::new();
+        #[cfg(feature = "oscars_backend")]
+        let global_scope = boa_gc::HandleScope::enter();
         let mc = gc.gc_collector();
         let root_shape = RootShape::new(&mc);
 
@@ -1283,6 +1287,8 @@ impl ContextBuilder {
             root_shape,
             parser_identifier: 0,
             gc,
+            #[cfg(feature = "oscars_backend")]
+            global_scope,
             can_block: self.can_block,
             data: HostDefined::default(),
         };
diff --git a/core/engine/src/environments/runtime/mod.rs b/core/engine/src/environments/runtime/mod.rs
index bdcc1bea321..ad4c7be8e1f 100644
--- a/core/engine/src/environments/runtime/mod.rs
+++ b/core/engine/src/environments/runtime/mod.rs
@@ -227,7 +227,7 @@ impl EnvironmentStack {
         let index = self.depth;
 
         self.push_env(
-            Environment::Declarative(Gc::new(
+            Environment::Declarative(boa_gc::allocate_rooted(
                 &gc,
                 DeclarativeEnvironment::new(
                     DeclarativeEnvironmentKind::Lexical(LexicalEnvironment::new(bindings_count)),
@@ -254,7 +254,7 @@ impl EnvironmentStack {
         let (poisoned, with) = self.compute_poisoned_with(global);
 
         self.push_env(
-            Environment::Declarative(Gc::new(
+            Environment::Declarative(boa_gc::allocate_rooted(
                 gc,
                 DeclarativeEnvironment::new(
                     DeclarativeEnvironmentKind::Function(FunctionEnvironment::new(
@@ -274,7 +274,7 @@ impl EnvironmentStack {
     pub(crate) fn push_module(&mut self, scope: Scope, gc: &boa_gc::MutationContext<'static, '_>) {
         let num_bindings = scope.num_bindings_non_local();
         self.push_env(
-            Environment::Declarative(Gc::new(
+            Environment::Declarative(boa_gc::allocate_rooted(
                 gc,
                 DeclarativeEnvironment::new(
                     DeclarativeEnvironmentKind::Module(ModuleEnvironment::new(num_bindings, scope)),
@@ -430,7 +430,7 @@ impl EnvironmentStack {
 
     /// Push an environment onto the chain.
     fn push_env(&mut self, env: Environment, mc: &boa_gc::MutationContext<'static, '_>) {
-        self.tip = Some(Gc::new(
+        self.tip = Some(boa_gc::allocate_rooted(
             mc,
             EnvironmentNode {
                 env,
diff --git a/core/engine/src/module/synthetic.rs b/core/engine/src/module/synthetic.rs
index ad178da7cfc..201a004086a 100644
--- a/core/engine/src/module/synthetic.rs
+++ b/core/engine/src/module/synthetic.rs
@@ -128,7 +128,7 @@ impl SyntheticModuleInitializer {
     {
         // Hopefully, this unsafe operation will be replaced by the `CoerceUnsized` API in the
         // future: https://github.com/rust-lang/rust/issues/18598
-        let ptr = Gc::into_raw(Gc::new(
+        let ptr = Gc::into_raw(boa_gc::allocate_rooted(
             mc,
             Callback {
                 f: closure,
diff --git a/core/engine/src/native_function/continuation.rs b/core/engine/src/native_function/continuation.rs
index 651bd9de071..51ded311742 100644
--- a/core/engine/src/native_function/continuation.rs
+++ b/core/engine/src/native_function/continuation.rs
@@ -115,7 +115,7 @@ impl NativeCoroutine {
     {
         // Hopefully, this unsafe operation will be replaced by the `CoerceUnsized` API in the
         // future: https://github.com/rust-lang/rust/issues/18598
-        let ptr = Gc::into_raw(Gc::new(
+        let ptr = Gc::into_raw(boa_gc::allocate_rooted(
             mc,
             Coroutine {
                 f: closure,
diff --git a/core/engine/src/native_function/mod.rs b/core/engine/src/native_function/mod.rs
index 1cdc33780eb..525df98cb85 100644
--- a/core/engine/src/native_function/mod.rs
+++ b/core/engine/src/native_function/mod.rs
@@ -288,7 +288,7 @@ impl NativeFunction {
     {
         // Hopefully, this unsafe operation will be replaced by the `CoerceUnsized` API in the
         // future: https://github.com/rust-lang/rust/issues/18598
-        let ptr = Gc::into_raw(Gc::new(
+        let ptr = Gc::into_raw(boa_gc::allocate_rooted(
             mc,
             Closure {
                 f: closure,
diff --git a/core/engine/src/object/jsobject.rs b/core/engine/src/object/jsobject.rs
index 00abeba6cce..377f4bc1ed4 100644
--- a/core/engine/src/object/jsobject.rs
+++ b/core/engine/src/object/jsobject.rs
@@ -122,7 +122,7 @@ impl JsObject {
         object: Object<T>,
         vtable: &'static InternalObjectMethods,
     ) -> Self {
-        let inner = Gc::new(
+        let inner = boa_gc::allocate_rooted(
             mc,
             VTableObject {
                 object: GcRefCell::new(object),
@@ -177,7 +177,7 @@ impl JsObject {
         data: T,
     ) -> Self {
         let internal_methods = data.internal_methods();
-        let inner = Gc::new(
+        let inner = boa_gc::allocate_rooted(
             mc,
             VTableObject {
                 object: GcRefCell::new(Object {
@@ -201,7 +201,7 @@ impl JsObject {
         data: T,
     ) -> JsObject<T> {
         let internal_methods = data.internal_methods();
-        let inner = Gc::new(
+        let inner = boa_gc::allocate_rooted(
             mc,
             VTableObject {
                 object: GcRefCell::new(Object {
@@ -1032,6 +1032,8 @@ impl<T: NativeObject> JsObject<T> {
     }
 
     pub(crate) fn from_inner(inner: Gc<'static, VTableObject<T>>) -> Self {
+        #[cfg(feature = "oscars_backend")]
+        let _root = boa_gc::Local::new(inner.clone());
         Self { inner }
     }
 
@@ -1051,7 +1053,7 @@ impl<T: NativeObject> JsObject<T> {
         data: T,
     ) -> Self {
         let internal_methods = data.internal_methods();
-        let inner = Gc::new(
+        let inner = boa_gc::allocate_rooted(
             mc,
             VTableObject {
                 object: GcRefCell::new(Object {
@@ -1101,7 +1103,7 @@ impl<T: NativeObject> JsObject<T> {
         data: T,
     ) -> Self {
         let internal_methods = data.internal_methods();
-        let inner = Gc::new(
+        let inner = boa_gc::allocate_rooted(
             mc,
             VTableObject {
                 object: GcRefCell::new(Object {
diff --git a/core/engine/src/object/shape/shared_shape/mod.rs b/core/engine/src/object/shape/shared_shape/mod.rs
index 2f99dd5d587..99bbb4f04de 100644
--- a/core/engine/src/object/shape/shared_shape/mod.rs
+++ b/core/engine/src/object/shape/shared_shape/mod.rs
@@ -166,7 +166,7 @@ impl SharedShape {
     /// Create a new [`SharedShape`] using the given context.
     fn new(mc: &boa_gc::MutationContext<'static, '_>, inner: Inner) -> Self {
         Self {
-            inner: Gc::new(mc, inner),
+            inner: boa_gc::allocate_rooted(mc, inner),
         }
     }
 
diff --git a/core/engine/src/object/shape/unique_shape.rs b/core/engine/src/object/shape/unique_shape.rs
index 02d7c3e1cc4..33d62b08234 100644
--- a/core/engine/src/object/shape/unique_shape.rs
+++ b/core/engine/src/object/shape/unique_shape.rs
@@ -41,7 +41,7 @@ impl UniqueShape {
         property_table: PropertyTableInner,
     ) -> Self {
         Self {
-            inner: Gc::new(
+            inner: boa_gc::allocate_rooted(
                 mc,
                 Inner {
                     property_table: RefCell::new(property_table),
diff --git a/core/engine/src/realm.rs b/core/engine/src/realm.rs
index 39d1a382b4d..2050c5a9052 100644
--- a/core/engine/src/realm.rs
+++ b/core/engine/src/realm.rs
@@ -90,11 +90,11 @@ impl Realm {
         let global_this = hooks
             .create_global_this(&intrinsics)
             .unwrap_or_else(|| global_object.clone());
-        let environment = Gc::new(mc, DeclarativeEnvironment::global());
+        let environment = boa_gc::allocate_rooted(mc, DeclarativeEnvironment::global());
         let scope = Scope::new_global();
 
         let realm = Self {
-            inner: Gc::new(
+            inner: boa_gc::allocate_rooted(
                 mc,
                 Inner {
                     intrinsics,
diff --git a/core/engine/src/value/inner/nan_boxed.rs b/core/engine/src/value/inner/nan_boxed.rs
index e729ce793d8..978e637eb46 100644
--- a/core/engine/src/value/inner/nan_boxed.rs
+++ b/core/engine/src/value/inner/nan_boxed.rs
@@ -1014,6 +1014,9 @@ fn bigint() {
 
 #[test]
 fn object() {
+    #[cfg(feature = "oscars_backend")]
+    let _scope = boa_gc::HandleScope::enter();
+
     let object = JsObject::with_null_proto(&unsafe { boa_gc::MutationContext::global() });
     let v = NanBoxedValue::object(object.clone());
     assert_type!(v is object(object));
diff --git a/core/engine/src/value/tests.rs b/core/engine/src/value/tests.rs
index 15ca96277f0..2177c9f320d 100644
--- a/core/engine/src/value/tests.rs
+++ b/core/engine/src/value/tests.rs
@@ -128,6 +128,9 @@ fn hash_rational() {
 
 #[test]
 fn hash_object() {
+    #[cfg(feature = "oscars_backend")]
+    let _scope = boa_gc::HandleScope::enter();
+
     let object1 = JsValue::new(JsObject::with_null_proto(&unsafe {
         boa_gc::MutationContext::global()
     }));
diff --git a/core/engine/src/vm/mod.rs b/core/engine/src/vm/mod.rs
index cc4ee8247b7..e2af29e304c 100644
--- a/core/engine/src/vm/mod.rs
+++ b/core/engine/src/vm/mod.rs
@@ -407,7 +407,7 @@ impl Vm {
     pub(crate) fn new(realm: Realm, mc: &boa_gc::MutationContext<'static, '_>) -> Self {
         let mut frames = Vec::with_capacity(16);
         frames.push(CallFrame::new(
-            Gc::new(mc, CodeBlock::new(JsString::default(), 0, true)),
+            boa_gc::allocate_rooted(mc, CodeBlock::new(JsString::default(), 0, true)),
             None,
             EnvironmentStack::new(),
             realm,
diff --git a/core/gc/src/context.rs b/core/gc/src/context.rs
index 5cf014b83fa..493d7887b1c 100644
--- a/core/gc/src/context.rs
+++ b/core/gc/src/context.rs
@@ -22,12 +22,22 @@ thread_local! {
             MutationContext::from_collector_erased(*c)
         }))
     });
+
+    static TRACKER: std::cell::RefCell<Option<oscars::collectors::mark_sweep_branded::Root<'static, crate::scope_tracker::HandleScopeTracker>>> = std::cell::RefCell::new(None);
 }
 
 #[cfg(feature = "oscars_backend")]
 impl GcContext {
     #[must_use]
     pub fn new() -> Self {
+        TRACKER.with(|tracker| {
+            if tracker.borrow().is_none() {
+                let mc = DUMMY.with(|dummy| *dummy);
+                let handle = Gc::new(mc, crate::scope_tracker::HandleScopeTracker);
+                let root = mc.root(handle).expect("Failed to root HandleScopeTracker");
+                *tracker.borrow_mut() = Some(root);
+            }
+        });
         Self
     }
 
diff --git a/core/gc/src/lib.rs b/core/gc/src/lib.rs
index b50c2dda207..95eb061aa2e 100644
--- a/core/gc/src/lib.rs
+++ b/core/gc/src/lib.rs
@@ -30,8 +30,15 @@ mod pointers;
 mod trace;
 
 pub mod context;
+#[cfg(feature = "oscars_backend")]
+pub(crate) mod scope;
+#[cfg(feature = "oscars_backend")]
+pub(crate) mod scope_tracker;
 pub use context::GcContext;
 
+#[cfg(feature = "oscars_backend")]
+pub use scope::{HandleScope, Local};
+
 #[cfg(not(feature = "oscars_backend"))]
 pub(crate) mod internals;
 
@@ -176,3 +183,21 @@ pub fn force_collect() {
     mc.collect();
     crate::context::GcContext::new().force_collect();
 }
+
+#[cfg(feature = "oscars_backend")]
+pub fn allocate_rooted<'gc, T: Trace + Finalize + 'gc>(
+    mc: &MutationContext<'gc, '_>,
+    value: T,
+) -> Gc<'gc, T> {
+    let gc = Gc::new(mc, value);
+    Local::new(gc);
+    gc
+}
+
+#[cfg(not(feature = "oscars_backend"))]
+pub fn allocate_rooted<'gc, T: Trace + Finalize + 'gc>(
+    mc: &MutationContext<'gc, '_>,
+    value: T,
+) -> Gc<'gc, T> {
+    Gc::new(mc, value)
+}
diff --git a/core/gc/src/pointers/gc.rs b/core/gc/src/pointers/gc.rs
index 3ef43301f5f..fd604351eec 100644
--- a/core/gc/src/pointers/gc.rs
+++ b/core/gc/src/pointers/gc.rs
@@ -175,10 +175,15 @@ impl<'gc, T: Trace + ?Sized + 'static> Gc<'gc, T> {
         // Note: Allocator can cause Collector to run
         let inner_ptr = Allocator::alloc_gc(GcBox::new(value));
 
-        Self {
+        let gc = Self {
             inner_ptr,
             marker: PhantomData,
-        }
+        };
+
+        #[cfg(feature = "oscars_backend")]
+        crate::Local::new(gc.clone());
+
+        gc
     }
 
     /// Constructs a new `Gc<T>` while giving you a `WeakGc<T>` to the allocation, to allow
diff --git a/core/gc/src/scope.rs b/core/gc/src/scope.rs
new file mode 100644
index 00000000000..cd1f7055c18
--- /dev/null
+++ b/core/gc/src/scope.rs
@@ -0,0 +1,110 @@
+use std::cell::RefCell;
+use std::marker::PhantomData;
+use std::ptr::NonNull;
+
+use crate::{Gc, Trace, Tracer};
+
+/// A type-erased local root for tracing.
+#[derive(Clone, Copy)]
+pub(crate) struct ErasedRoot {
+    /// The erased `PoolPointer` (`NonNull<()>`) from a `Gc<'_, T>`.
+    ptr: NonNull<()>,
+    /// A function that casts the pointer back to `Gc<'_, T>` and marks it.
+    trace_fn: unsafe fn(NonNull<()>, &mut Tracer<'_>),
+}
+
+impl ErasedRoot {
+    fn new<T: Trace>(gc: Gc<'_, T>) -> Self {
+        unsafe fn trace_gc<T: Trace>(ptr: NonNull<()>, tracer: &mut Tracer<'_>) {
+            unsafe {
+                // Reconstruct the Gc pointer
+                let gc: Gc<'_, T> = std::mem::transmute(ptr);
+                tracer.mark(&gc);
+            }
+        }
+
+        Self {
+            // Safe because Gc has exactly the same memory layout as NonNull.
+            ptr: unsafe { std::mem::transmute_copy(&gc) },
+            trace_fn: trace_gc::<T>,
+        }
+    }
+
+    pub(crate) unsafe fn trace(&self, tracer: &mut Tracer<'_>) {
+        unsafe { (self.trace_fn)(self.ptr, tracer) };
+    }
+}
+
+thread_local! {
+    /// A stack of handle scopes for the current thread.
+    pub(crate) static SCOPE_STACK: RefCell<Vec<Vec<ErasedRoot>>> = RefCell::new(Vec::new());
+}
+
+/// A scope for tracking local handles.
+pub struct HandleScope {
+    _marker: PhantomData<*mut ()>, // Not Send or Sync
+}
+
+impl HandleScope {
+    /// Enter a new handle scope.
+    #[must_use]
+    pub fn enter() -> Self {
+        SCOPE_STACK.with(|stack| stack.borrow_mut().push(Vec::new()));
+        Self {
+            _marker: PhantomData,
+        }
+    }
+}
+
+impl Drop for HandleScope {
+    fn drop(&mut self) {
+        SCOPE_STACK.with(|stack| {
+            stack
+                .borrow_mut()
+                .pop()
+                .expect("HandleScope popped without being pushed");
+        });
+    }
+}
+
+/// A local handle to a GC-managed value, scoped to the current `HandleScope`.
+#[derive(Debug)]
+pub struct Local<'gc, T: Trace + 'gc> {
+    inner: Gc<'gc, T>,
+}
+
+impl<'gc, T: Trace + 'gc> Local<'gc, T> {
+    /// Create a new local handle from a GC pointer.
+    pub fn new(gc: Gc<'gc, T>) -> Self {
+        SCOPE_STACK.with(|stack| {
+            let mut stack = stack.borrow_mut();
+            if let Some(top) = stack.last_mut() {
+                top.push(ErasedRoot::new(gc));
+            } else {
+                panic!("Cannot create Local without an active HandleScope");
+            }
+        });
+
+        Self { inner: gc }
+    }
+
+    pub fn into_inner(self) -> Gc<'gc, T> {
+        self.inner
+    }
+}
+
+impl<'gc, T: Trace + 'gc> Clone for Local<'gc, T> {
+    fn clone(&self) -> Self {
+        Self::new(self.inner)
+    }
+}
+
+impl<'gc, T: Trace + 'gc> Copy for Local<'gc, T> {}
+
+impl<'gc, T: Trace + 'gc> std::ops::Deref for Local<'gc, T> {
+    type Target = Gc<'gc, T>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.inner
+    }
+}
diff --git a/core/gc/src/scope_tracker.rs b/core/gc/src/scope_tracker.rs
new file mode 100644
index 00000000000..392c5bddf39
--- /dev/null
+++ b/core/gc/src/scope_tracker.rs
@@ -0,0 +1,22 @@
+use crate::scope::SCOPE_STACK;
+use crate::{Finalize, Trace, Tracer};
+
+pub(crate) struct HandleScopeTracker;
+
+impl Finalize for HandleScopeTracker {
+    fn finalize(&self) {}
+}
+
+unsafe impl Trace for HandleScopeTracker {
+    unsafe fn trace(&self, tracer: &mut Tracer<'_>) {
+        SCOPE_STACK.with(|stack| {
+            for scope in stack.borrow().iter() {
+                for root in scope.iter() {
+                    unsafe {
+                        root.trace(tracer);
+                    }
+                }
+            }
+        });
+    }
+}

From 0efd528c6d32d4f6ef7f7cb94e819701f8300c21 Mon Sep 17 00:00:00 2001
From: shruti2522 <shruti.apc01@gmail.com>
Date: Thu, 20 Aug 2026 21:57:53 +0000
Subject: [PATCH 09/19] Enable oscars_backend in boa_wasm

---
 ffi/wasm/Cargo.toml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/ffi/wasm/Cargo.toml b/ffi/wasm/Cargo.toml
index 55b997db512..ec51c1b2d94 100644
--- a/ffi/wasm/Cargo.toml
+++ b/ffi/wasm/Cargo.toml
@@ -27,6 +27,7 @@ default = [
     "boa_engine/intl_bundled",
     "boa_engine/temporal",
     "boa_engine/xsum",
+    "boa_engine/oscars_backend",
 ]
 
 [lib]

From 389ac73c6a6ea6feb7f0a617794ba3936e4f6d5f Mon Sep 17 00:00:00 2001
From: shruti2522 <shruti.apc01@gmail.com>
Date: Sun, 23 Aug 2026 07:50:56 +0000
Subject: [PATCH 10/19] fix heap UAF in ListFormat

---
 .../src/builtins/intl/list_format/mod.rs      | 71 +++++++++++--------
 1 file changed, 43 insertions(+), 28 deletions(-)

diff --git a/core/engine/src/builtins/intl/list_format/mod.rs b/core/engine/src/builtins/intl/list_format/mod.rs
index 4c9f79b0d9e..6f5aa08b680 100644
--- a/core/engine/src/builtins/intl/list_format/mod.rs
+++ b/core/engine/src/builtins/intl/list_format/mod.rs
@@ -227,25 +227,32 @@ impl ListFormat {
     /// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/ListFormat/format
     fn format(this: &JsValue, args: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
         // 1. Let lf be the this value.
-        // 2. Perform ? RequireInternalSlot(lf, [[InitializedListFormat]]).
-        let object = this.as_object();
-        let lf = object
-            .as_ref()
-            .and_then(|o| o.downcast_ref::<Self>())
-            .ok_or_else(|| {
-                JsNativeError::typ()
-                    .with_message("`format` can only be called on a `ListFormat` object")
-            })?;
-
-        // 3. Let stringList be ? StringListFromIterable(list).
+        // 2. Perform ? RequireInternalSlot(lf, [[InitializedListFormat]]).
+        //    Validate the `this` type BEFORE collecting strings, but do NOT hold the
+        //    borrow across the iterator call below: `string_list_from_iterable` runs
+        //    arbitrary JS (iterator protocol) which can trigger GC and free/move the
+        //    GC-managed object that `downcast_ref` borrows from, causing a UAF.
+        let object = this.as_object().filter(|o| o.is::<Self>()).ok_or_else(|| {
+            JsNativeError::typ()
+                .with_message("`format` can only be called on a `ListFormat` object")
+        })?;
+
+        // 3. Let stringList be ? StringListFromIterable(list).
         // TODO: support for UTF-16 unpaired surrogates formatting
+        // SAFETY: We must collect strings first (which runs JS / may trigger GC) and
+        // only THEN borrow `lf`.  Holding a `Ref<'_, T>` across a GC point is a UAF.
         let strings = string_list_from_iterable(args.get_or_undefined(0), context)?;
 
+        // Borrow `lf` only after all GC-triggering operations are complete.
+        let lf = object
+            .downcast_ref::<Self>()
+            .expect("already checked above that the object is a ListFormat");
+
         let formatted = lf
             .native
             .format_to_string(strings.into_iter().map(|s| s.to_std_string_escaped()));
 
-        // 4. Return ! FormatList(lf, stringList).
+        // 4. Return ! FormatList(lf, stringList).
         Ok(js_string!(formatted).into())
     }
 
@@ -345,31 +352,39 @@ impl ListFormat {
         }
 
         // 1. Let lf be the this value.
-        // 2. Perform ? RequireInternalSlot(lf, [[InitializedListFormat]]).
-        let object = this.as_object();
-        let lf = object
-            .as_ref()
-            .and_then(|o| o.downcast_ref::<Self>())
-            .ok_or_else(|| {
-                JsNativeError::typ()
-                    .with_message("`formatToParts` can only be called on a `ListFormat` object")
-            })?;
-
-        // 3. Let stringList be ? StringListFromIterable(list).
+        // 2. Perform ? RequireInternalSlot(lf, [[InitializedListFormat]]).
+        //    Validate the `this` type BEFORE collecting strings, but do NOT hold the
+        //    borrow across the iterator call below: `string_list_from_iterable` runs
+        //    arbitrary JS (iterator protocol) which can trigger GC and free/move the
+        //    GC-managed object that `downcast_ref` borrows from, causing a UAF.
+        let object = this.as_object().filter(|o| o.is::<Self>()).ok_or_else(|| {
+            JsNativeError::typ()
+                .with_message("`formatToParts` can only be called on a `ListFormat` object")
+        })?;
+
+        // 3. Let stringList be ? StringListFromIterable(list).
         // TODO: support for UTF-16 unpaired surrogates formatting
-        let strings = string_list_from_iterable(args.get_or_undefined(0), context)?
+        // SAFETY: We must collect strings first (which runs JS / may trigger GC) and
+        // only THEN borrow `lf`.  Holding a `Ref<'_, T>` across a GC point is a UAF.
+        let strings: Vec<String> = string_list_from_iterable(args.get_or_undefined(0), context)?
             .into_iter()
-            .map(|s| s.to_std_string_escaped());
+            .map(|s| s.to_std_string_escaped())
+            .collect();
+
+        // Borrow `lf` only after all GC-triggering operations are complete.
+        let lf = object
+            .downcast_ref::<Self>()
+            .expect("already checked above that the object is a ListFormat");
 
-        // 4. Return ! FormatListToParts(lf, stringList).
+        // 4. Return ! FormatListToParts(lf, stringList).
 
         // Abstract operation `FormatListToParts ( listFormat, list )`
         // https://tc39.es/ecma402/#sec-formatlisttoparts
 
-        // 1. Let parts be ! CreatePartsFromList(listFormat, list).
+        // 1. Let parts be ! CreatePartsFromList(listFormat, list).
         let mut parts = PartsCollector(Vec::new());
         lf.native
-            .format(strings)
+            .format(strings.into_iter())
             .write_to_parts(&mut parts)
             .map_err(|e| JsNativeError::typ().with_message(e.to_string()))?;
 

From 0cc91550058943d5ddff5d6350a3474063dd8c0c Mon Sep 17 00:00:00 2001
From: shruti2522 <shruti.apc01@gmail.com>
Date: Sun, 23 Aug 2026 08:08:04 +0000
Subject: [PATCH 11/19] fix anchor crash

---
 core/engine/src/builtins/intl/collator/mod.rs | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/core/engine/src/builtins/intl/collator/mod.rs b/core/engine/src/builtins/intl/collator/mod.rs
index d0c0f11072e..d20ef3b56a4 100644
--- a/core/engine/src/builtins/intl/collator/mod.rs
+++ b/core/engine/src/builtins/intl/collator/mod.rs
@@ -363,9 +363,11 @@ impl Collator {
                     |_, args, collator, context| {
                         // 1. Let collator be F.[[Collator]].
                         // 2. Assert: Type(collator) is Object and collator has an [[InitializedCollator]] internal slot.
-                        let collator = collator
-                            .downcast_ref::<Self>()
-                            .js_expect("checked above that the object was a collator object")?;
+                        //
+                        // SAFETY: We must resolve the string arguments (which run JS /
+                        // may trigger GC) BEFORE borrowing `collator` via downcast_ref.
+                        // Holding a Ref<'_, T> across a GC point is a use-after-free
+                        // because GC can collect the backing object while the borrow is live.
 
                         // 3. If x is not provided, let x be undefined.
                         // 5. Let X be ? ToString(x).
@@ -383,8 +385,12 @@ impl Collator {
                             .iter()
                             .collect::<Vec<_>>();
 
-                        // 7. Return CompareStrings(collator, X, Y).
+                        // Borrow collator AFTER all GC-triggering work is done.
+                        let collator = collator
+                            .downcast_ref::<Self>()
+                            .js_expect("checked above that the object was a collator object")?;
 
+                        // 7. Return CompareStrings(collator, X, Y).
                         let result = collator.collator.as_borrowed().compare_utf16(&x, &y) as i32;
 
                         Ok(result.into())

From 3f68447a59fe741580be754f11d74e8c81bb0558 Mon Sep 17 00:00:00 2001
From: shruti2522 <shruti.apc01@gmail.com>
Date: Sun, 23 Aug 2026 08:21:41 +0000
Subject: [PATCH 12/19] fix constructor crash

---
 core/engine/src/builtins/intl/collator/mod.rs | 34 ++++++--
 .../src/builtins/intl/list_format/mod.rs      | 86 +++++++++++--------
 2 files changed, 77 insertions(+), 43 deletions(-)

diff --git a/core/engine/src/builtins/intl/collator/mod.rs b/core/engine/src/builtins/intl/collator/mod.rs
index d20ef3b56a4..e2e393b0c00 100644
--- a/core/engine/src/builtins/intl/collator/mod.rs
+++ b/core/engine/src/builtins/intl/collator/mod.rs
@@ -340,19 +340,31 @@ impl Collator {
             JsNativeError::typ()
                 .with_message("`resolvedOptions` can only be called on a `Collator` object")
         })?;
-        let collator_obj = this.clone();
-        let mut collator = this.downcast_mut::<Self>().ok_or_else(|| {
-            JsNativeError::typ()
-                .with_message("`resolvedOptions` can only be called on a `Collator` object")
-        })?;
 
         // 3. If collator.[[BoundCompare]] is undefined, then
         //     a. Let F be a new built-in function object as defined in 10.3.3.1.
         //     b. Set F.[[Collator]] to collator.
         //     c. Set collator.[[BoundCompare]] to F.
-        let bound_compare = if let Some(f) = collator.bound_compare.clone() {
+        //
+        // SAFETY: We must NOT hold a downcast_mut borrow across context.realm() /
+        // context.gc_collector() calls, as those can trigger a GC collection that
+        // frees the backing object while the mutable borrow guard is live (UAF).
+        //
+        // Pattern: read [[BoundCompare]] in a scoped block, drop the borrow, build the
+        // function with no borrow held, then take a fresh borrow only to write back.
+        let existing = {
+            let collator = this.downcast_ref::<Self>().ok_or_else(|| {
+                JsNativeError::typ()
+                    .with_message("`resolvedOptions` can only be called on a `Collator` object")
+            })?;
+            collator.bound_compare.clone()
+        }; // borrow dropped here
+
+        let bound_compare = if let Some(f) = existing {
             f
         } else {
+            // Build the bound compare function with no borrow held on `this`
+            let collator_obj = this.clone();
             let bound_compare = FunctionObjectBuilder::new(
                 context.realm(),
                 context.gc_collector(),
@@ -401,7 +413,15 @@ impl Collator {
             .length(2)
             .build();
 
-            collator.bound_compare = Some(bound_compare.clone());
+            // take a fresh borrow to write back [[BoundCompare]].  No context calls
+            // follow this so the borrow is safe.
+            this.downcast_mut::<Self>()
+                .ok_or_else(|| {
+                    JsNativeError::typ()
+                        .with_message("`resolvedOptions` can only be called on a `Collator` object")
+                })?
+                .bound_compare = Some(bound_compare.clone());
+
             bound_compare
         };
 
diff --git a/core/engine/src/builtins/intl/list_format/mod.rs b/core/engine/src/builtins/intl/list_format/mod.rs
index 6f5aa08b680..0ce0bec6cc9 100644
--- a/core/engine/src/builtins/intl/list_format/mod.rs
+++ b/core/engine/src/builtins/intl/list_format/mod.rs
@@ -364,37 +364,44 @@ impl ListFormat {
 
         // 3. Let stringList be ? StringListFromIterable(list).
         // TODO: support for UTF-16 unpaired surrogates formatting
-        // SAFETY: We must collect strings first (which runs JS / may trigger GC) and
-        // only THEN borrow `lf`.  Holding a `Ref<'_, T>` across a GC point is a UAF.
+        // SAFETY: Collect the JS strings first (runs JS / may trigger GC), before
+        // borrowing `lf`.  A Ref<'_, T> must NOT be held across any GC point.
         let strings: Vec<String> = string_list_from_iterable(args.get_or_undefined(0), context)?
             .into_iter()
             .map(|s| s.to_std_string_escaped())
             .collect();
 
-        // Borrow `lf` only after all GC-triggering operations are complete.
-        let lf = object
-            .downcast_ref::<Self>()
-            .expect("already checked above that the object is a ListFormat");
-
         // 4. Return ! FormatListToParts(lf, stringList).
 
         // Abstract operation `FormatListToParts ( listFormat, list )`
         // https://tc39.es/ecma402/#sec-formatlisttoparts
 
         // 1. Let parts be ! CreatePartsFromList(listFormat, list).
-        let mut parts = PartsCollector(Vec::new());
-        lf.native
-            .format(strings.into_iter())
-            .write_to_parts(&mut parts)
-            .map_err(|e| JsNativeError::typ().with_message(e.to_string()))?;
-
-        // 2. Let result be ! ArrayCreate(0).
+        //
+        // SAFETY: Perform the pure native formatting inside a scoped block so that
+        // the Ref<'_, ListFormat> borrow guard is dropped BEFORE we re-enter context
+        // (Array::array_create, context.gc_collector, create_data_property_or_throw).
+        // All of those can trigger a GC collection cycle, which would be a UAF if we
+        // still held the Ref
+        let parts = {
+            let lf = object
+                .downcast_ref::<Self>()
+                .expect("already checked above that the object is a ListFormat");
+            let mut collector = PartsCollector(Vec::new());
+            lf.native
+                .format(strings.into_iter())
+                .write_to_parts(&mut collector)
+                .map_err(|e| JsNativeError::typ().with_message(e.to_string()))?;
+            collector.0
+        }; // Ref<'_, ListFormat> dropped here; safe to use context below
+
+        // 2. Let result be ! ArrayCreate(0).
         let result = Array::array_create(0, None, context)
             .js_expect("creating an empty array with default proto must not fail")?;
 
         // 3. Let n be 0.
         // 4. For each Record { [[Type]], [[Value]] } part in parts, do
-        for (n, part) in parts.0.into_iter().enumerate() {
+        for (n, part) in parts.into_iter().enumerate() {
             // a. Let O be OrdinaryObjectCreate(%Object.prototype%).
             let o = context.intrinsics().templates().ordinary_object().create(
                 context.gc_collector(),
@@ -402,15 +409,15 @@ impl ListFormat {
                 vec![],
             );
 
-            // b. Perform ! CreateDataPropertyOrThrow(O, "type", part.[[Type]]).
+            // b. Perform ! CreateDataPropertyOrThrow(O, "type", part.[[Type]]).
             o.create_data_property_or_throw(js_string!("type"), js_string!(part.typ()), context)
                 .js_expect("operation must not fail per the spec")?;
 
-            // c. Perform ! CreateDataPropertyOrThrow(O, "value", part.[[Value]]).
+            // c. Perform ! CreateDataPropertyOrThrow(O, "value", part.[[Value]]).
             o.create_data_property_or_throw(js_string!("value"), js_string!(part.value()), context)
                 .js_expect("operation must not fail per the spec")?;
 
-            // d. Perform ! CreateDataPropertyOrThrow(result, ! ToString(n), O).
+            // d. Perform ! CreateDataPropertyOrThrow(result, ! ToString(n), O).
             result
                 .create_data_property_or_throw(n, o, context)
                 .js_expect("operation must not fail per the spec")?;
@@ -434,15 +441,27 @@ impl ListFormat {
     /// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/ListFormat/resolvedOptions
     fn resolved_options(this: &JsValue, _: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
         // 1. Let lf be the this value.
-        // 2. Perform ? RequireInternalSlot(lf, [[InitializedListFormat]]).
-        let object = this.as_object();
-        let lf = object
-            .as_ref()
-            .and_then(|o| o.downcast_ref::<Self>())
-            .ok_or_else(|| {
-                JsNativeError::typ()
-                    .with_message("`resolvedOptions` can only be called on a `ListFormat` object")
-            })?;
+        // 2. Perform ? RequireInternalSlot(lf, [[InitializedListFormat]]).
+        //
+        // SAFETY: Extract all data from `lf` into owned values inside a scoped block so
+        // the Ref<'_, ListFormat> borrow guard is dropped BEFORE we touch `context`.
+        // GC allocations (context.gc_collector(), js_string!, create_data_property_or_throw)
+        // can trigger a collection cycle; holding a Ref<'_, T> across a GC point is a
+        // use-after-free because the GC may collect the backing object while the borrow
+        // is live.
+        let (locale_str, typ, style) = {
+            let object = this.as_object();
+            let lf = object
+                .as_ref()
+                .and_then(|o| o.downcast_ref::<Self>())
+                .ok_or_else(|| {
+                    JsNativeError::typ().with_message(
+                        "`resolvedOptions` can only be called on a `ListFormat` object",
+                    )
+                })?;
+            // Clone/copy out the cheap data we need; Ref is dropped at end of this block.
+            (lf.locale.to_string(), lf.typ, lf.style)
+        }; // ← Ref<'_, ListFormat> dropped here, safe to use context below
 
         // 3. Let options be OrdinaryObjectCreate(%Object.prototype%).
         let options = context.intrinsics().templates().ordinary_object().create(
@@ -455,18 +474,14 @@ impl ListFormat {
         //     a. Let p be the Property value of the current row.
         //     b. Let v be the value of lf's internal slot whose name is the Internal Slot value of the current row.
         //     c. Assert: v is not undefined.
-        //     d. Perform ! CreateDataPropertyOrThrow(options, p, v).
+        //     d. Perform ! CreateDataPropertyOrThrow(options, p, v).
         options
-            .create_data_property_or_throw(
-                js_string!("locale"),
-                js_string!(lf.locale.to_string()),
-                context,
-            )
+            .create_data_property_or_throw(js_string!("locale"), js_string!(locale_str), context)
             .js_expect("operation must not fail per the spec")?;
         options
             .create_data_property_or_throw(
                 js_string!("type"),
-                match lf.typ {
+                match typ {
                     ListFormatType::Conjunction => js_string!("conjunction"),
                     ListFormatType::Disjunction => js_string!("disjunction"),
                     ListFormatType::Unit => js_string!("unit"),
@@ -477,7 +492,7 @@ impl ListFormat {
         options
             .create_data_property_or_throw(
                 js_string!("style"),
-                match lf.style {
+                match style {
                     ListLength::Wide => js_string!("long"),
                     ListLength::Short => js_string!("short"),
                     ListLength::Narrow => js_string!("narrow"),
@@ -487,7 +502,6 @@ impl ListFormat {
             )
             .js_expect("operation must not fail per the spec")?;
 
-        // 5. Return options.
         Ok(options.into())
     }
 }

From 478ebe6aa5bfa15e2b781bc123d38bbf02c86067 Mon Sep 17 00:00:00 2001
From: shruti2522 <shruti.apc01@gmail.com>
Date: Sun, 23 Aug 2026 13:59:49 +0000
Subject: [PATCH 13/19] fix: UAF in Collator::resolved_options and
 format_to_parts loop

Both functions held a Ref<'_, T> GC borrow guard across calls to
context.gc_collector() and create_data_property_or_throw(context),
which can trigger a GC collection cycle, freeing the backing object
while the borrow guard is still live (use-after-free -> heap corruption
-> malloc_consolidate abort).

Fix pattern (same as ListFormat::resolved_options):
- Extract all needed fields into owned values inside a scoped block
- Drop the Ref<'_, T> at end of the block
- All context/GC operations follow the block with no borrow live

Collator::resolved_options: locale_str, usage, sensitivity,
  ignore_punctuation, collation, numeric, case_first are copied out
  before any context operations.

format_to_parts: native formatting (lf.native.format()) moved into a
  scoped block so the Ref drops before the Array creation loop that
  repeatedly calls context.gc_collector() and create_data_property_or_throw.
---
 core/engine/src/builtins/intl/collator/mod.rs | 57 +++++++++++--------
 1 file changed, 34 insertions(+), 23 deletions(-)

diff --git a/core/engine/src/builtins/intl/collator/mod.rs b/core/engine/src/builtins/intl/collator/mod.rs
index e2e393b0c00..9a28d2c9251 100644
--- a/core/engine/src/builtins/intl/collator/mod.rs
+++ b/core/engine/src/builtins/intl/collator/mod.rs
@@ -441,15 +441,32 @@ impl Collator {
     /// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/Collator/resolvedOptions
     fn resolved_options(this: &JsValue, _: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
         // 1. Let collator be the this value.
-        // 2. Perform ? RequireInternalSlot(collator, [[InitializedCollator]]).
-        let object = this.as_object();
-        let collator = object
-            .as_ref()
-            .and_then(JsObject::downcast_ref::<Self>)
-            .ok_or_else(|| {
-                JsNativeError::typ()
-                    .with_message("`resolvedOptions` can only be called on a `Collator` object")
-            })?;
+        // 2. Perform ? RequireInternalSlot(collator, [[InitializedCollator]]).
+        //
+        // SAFETY: Extract all data from `collator` into owned values inside a scoped block
+        // so the Ref<'_, Collator> borrow guard is dropped BEFORE we touch `context`.
+        // GC allocations (context.gc_collector(), create_data_property_or_throw) can
+        // trigger a collection cycle; holding a Ref<'_, T> across a GC point is a UAF.
+        let (locale_str, usage, sensitivity, ignore_punctuation, collation, numeric, case_first) = {
+            let object = this.as_object();
+            let collator = object
+                .as_ref()
+                .and_then(JsObject::downcast_ref::<Self>)
+                .ok_or_else(|| {
+                    JsNativeError::typ()
+                        .with_message("`resolvedOptions` can only be called on a `Collator` object")
+                })?;
+            // Copy/clone all cheap fields; Ref is dropped at end of this block.
+            (
+                collator.locale.to_string(),
+                collator.usage,
+                collator.sensitivity,
+                collator.ignore_punctuation,
+                collator.collation,
+                collator.numeric,
+                collator.case_first,
+            )
+        }; // ← Ref<'_, Collator> dropped here, safe to use context below
 
         // 3. Let options be OrdinaryObjectCreate(%Object.prototype%).
         let options = context.intrinsics().templates().ordinary_object().create(
@@ -466,19 +483,15 @@ impl Collator {
         //         ii. If %Collator%.[[RelevantExtensionKeys]] does not contain extensionKey, then
         //             1. Let v be undefined.
         //     d. If v is not undefined, then
-        //         i. Perform ! CreateDataPropertyOrThrow(options, p, v).
+        //         i. Perform ! CreateDataPropertyOrThrow(options, p, v).
         // 5. Return options.
         options
-            .create_data_property_or_throw(
-                js_string!("locale"),
-                js_string!(collator.locale.to_string()),
-                context,
-            )
+            .create_data_property_or_throw(js_string!("locale"), js_string!(locale_str), context)
             .js_expect("operation must not fail per the spec")?;
         options
             .create_data_property_or_throw(
                 js_string!("usage"),
-                match collator.usage {
+                match usage {
                     Usage::Search => js_string!("search"),
                     Usage::Sort => js_string!("sort"),
                 },
@@ -488,7 +501,7 @@ impl Collator {
         options
             .create_data_property_or_throw(
                 js_string!("sensitivity"),
-                match collator.sensitivity {
+                match sensitivity {
                     Sensitivity::Base => js_string!("base"),
                     Sensitivity::Accent => js_string!("accent"),
                     Sensitivity::Case => js_string!("case"),
@@ -500,24 +513,23 @@ impl Collator {
         options
             .create_data_property_or_throw(
                 js_string!("ignorePunctuation"),
-                collator.ignore_punctuation,
+                ignore_punctuation,
                 context,
             )
             .js_expect("operation must not fail per the spec")?;
         options
             .create_data_property_or_throw(
                 js_string!("collation"),
-                collator
-                    .collation
+                collation
                     .map(|co| js_string!(co.as_str()))
                     .unwrap_or(js_string!("default")),
                 context,
             )
             .js_expect("operation must not fail per the spec")?;
         options
-            .create_data_property_or_throw(js_string!("numeric"), collator.numeric, context)
+            .create_data_property_or_throw(js_string!("numeric"), numeric, context)
             .js_expect("operation must not fail per the spec")?;
-        if let Some(kf) = collator.case_first {
+        if let Some(kf) = case_first {
             options
                 .create_data_property_or_throw(
                     js_string!("caseFirst"),
@@ -527,7 +539,6 @@ impl Collator {
                 .js_expect("operation must not fail per the spec")?;
         }
 
-        // 5. Return options.
         Ok(options.into())
     }
 }

From 18f007f3b7ac494e37a87a84fbc3271f86b90096 Mon Sep 17 00:00:00 2001
From: shruti2522 <shruti.apc01@gmail.com>
Date: Sun, 23 Aug 2026 14:29:52 +0000
Subject: [PATCH 14/19] fix: UAF in Intl resolved_options methods across
 multiple builtins

This fixes the same Use-After-Free (UAF) bug pattern found in
ListFormat and Collator across the remaining Intl built-ins:
- PluralRules
- DateTimeFormat
- NumberFormat
- Segmenter

The bug occurs when a `Ref<'_, T>` (via `downcast_ref`) is held
across a call to `ObjectInitializer::new(context)` or `options.property(..., context)`,
which can trigger a garbage collection cycle and free the underlying object.

The fix extracts all required fields into scoped variables before
interacting with the context.
---
 .../src/builtins/intl/date_time_format/mod.rs |  69 +++---
 .../src/builtins/intl/number_format/mod.rs    | 219 ++++++++++--------
 .../src/builtins/intl/plural_rules/mod.rs     |  89 ++++---
 .../engine/src/builtins/intl/segmenter/mod.rs |  29 ++-
 4 files changed, 242 insertions(+), 164 deletions(-)

diff --git a/core/engine/src/builtins/intl/date_time_format/mod.rs b/core/engine/src/builtins/intl/date_time_format/mod.rs
index 10a0abba1c3..ad8d84c2ff4 100644
--- a/core/engine/src/builtins/intl/date_time_format/mod.rs
+++ b/core/engine/src/builtins/intl/date_time_format/mod.rs
@@ -365,49 +365,66 @@ impl DateTimeFormat {
         //              a. Assert: conversion is number.
         //              b. Set v to 𝔽(v).
         //          ii. Perform ! CreateDataPropertyOrThrow(options, p, v).
-        let result = {
+        let (
+            locale_str,
+            calendar_algorithm,
+            numbering_system,
+            time_zone_str,
+            hour_cycle,
+            date_style,
+            time_style,
+        ) = {
             let dtf = dtf_object.borrow();
             let dtf = dtf.data();
 
+            let time_zone_str = match &dtf.time_zone {
+                FormatTimeZone::UtcOffset(offset) => {
+                    let seconds = offset.to_seconds();
+                    let hours = seconds / 3600;
+                    let minutes = (seconds.abs() % 3600) / 60;
+                    format!("{hours:+03}:{minutes:02}")
+                }
+                FormatTimeZone::Identifier((tz, _id)) => tz.to_string(),
+            };
+
+            (
+                dtf.locale.to_string(),
+                dtf.calendar_algorithm
+                    .as_ref()
+                    .map(|ca| js_string!(ca.as_str())),
+                dtf.numbering_system
+                    .as_ref()
+                    .map(|nu| js_string!(nu.as_str())),
+                time_zone_str,
+                dtf.hour_cycle,
+                dtf.date_style,
+                dtf.time_style,
+            )
+        };
+
+        let result = {
             let mut options = ObjectInitializer::new(context);
             options.property(
                 js_string!("locale"),
-                js_string!(dtf.locale.to_string()),
+                js_string!(locale_str),
                 Attribute::all(),
             );
 
-            if let Some(ca) = &dtf.calendar_algorithm {
-                options.property(
-                    js_string!("calendar"),
-                    js_string!(ca.as_str()),
-                    Attribute::all(),
-                );
+            if let Some(ca) = calendar_algorithm {
+                options.property(js_string!("calendar"), ca, Attribute::all());
             }
 
-            if let Some(nu) = &dtf.numbering_system {
-                options.property(
-                    js_string!("numberingSystem"),
-                    js_string!(nu.as_str()),
-                    Attribute::all(),
-                );
+            if let Some(nu) = numbering_system {
+                options.property(js_string!("numberingSystem"), nu, Attribute::all());
             }
 
-            let time_zone_str = match &dtf.time_zone {
-                FormatTimeZone::UtcOffset(offset) => {
-                    let seconds = offset.to_seconds();
-                    let hours = seconds / 3600;
-                    let minutes = (seconds.abs() % 3600) / 60;
-                    format!("{hours:+03}:{minutes:02}")
-                }
-                FormatTimeZone::Identifier((tz, _id)) => tz.to_string(),
-            };
             options.property(
                 js_string!("timeZone"),
                 js_string!(time_zone_str),
                 Attribute::all(),
             );
 
-            if let Some(hc) = &dtf.hour_cycle {
+            if let Some(hc) = hour_cycle {
                 options.property(
                     js_string!("hourCycle"),
                     js_string!(hc.as_str()),
@@ -418,7 +435,7 @@ impl DateTimeFormat {
                 options.property(js_string!("hour12"), hour12, Attribute::all());
             }
 
-            if let Some(ds) = dtf.date_style {
+            if let Some(ds) = date_style {
                 let ds_str = match ds {
                     DateStyle::Full => "full",
                     DateStyle::Long => "long",
@@ -432,7 +449,7 @@ impl DateTimeFormat {
                 );
             }
 
-            if let Some(ts) = dtf.time_style {
+            if let Some(ts) = time_style {
                 let ts_str = match ts {
                     TimeStyle::Full => "full",
                     TimeStyle::Long => "long",
diff --git a/core/engine/src/builtins/intl/number_format/mod.rs b/core/engine/src/builtins/intl/number_format/mod.rs
index 1ea97697ea7..bf748633cb5 100644
--- a/core/engine/src/builtins/intl/number_format/mod.rs
+++ b/core/engine/src/builtins/intl/number_format/mod.rs
@@ -656,8 +656,108 @@ impl NumberFormat {
         //     a. Set nf to ? UnwrapNumberFormat(nf).
         // 3. Perform ? RequireInternalSlot(nf, [[InitializedNumberFormat]]).
         let nf = unwrap_number_format(this, context)?;
-        let nf = nf.borrow();
-        let nf = nf.data();
+
+        let (
+            locale_str,
+            numbering_system,
+            style,
+            currency,
+            currency_display,
+            currency_sign,
+            unit,
+            unit_display,
+            minimum_integer_digits,
+            fraction_digits,
+            significant_digits,
+            use_grouping,
+            notation_str,
+            compact_display_str,
+            sign_display_str,
+            rounding_increment,
+            rounding_priority_str,
+            trailing_zero_display_str,
+        ) = {
+            let nf_borrow = nf.borrow();
+            let nf_data = nf_borrow.data();
+
+            let (currency, currency_display, currency_sign, unit, unit_display) =
+                match &nf_data.unit_options {
+                    UnitFormatOptions::Currency {
+                        currency,
+                        display,
+                        sign,
+                    } => (
+                        Some(currency.to_js_string()),
+                        Some(display.to_js_string()),
+                        Some(sign.to_js_string()),
+                        None,
+                        None,
+                    ),
+                    UnitFormatOptions::Unit { unit, display } => (
+                        None,
+                        None,
+                        None,
+                        Some(unit.to_js_string()),
+                        Some(display.to_js_string()),
+                    ),
+                    UnitFormatOptions::Decimal | UnitFormatOptions::Percent => {
+                        (None, None, None, None, None)
+                    }
+                };
+
+            let use_grouping = match nf_data.use_grouping {
+                GroupingStrategy::Auto => js_string!("auto").into(),
+                GroupingStrategy::Never => JsValue::from(false),
+                GroupingStrategy::Always => js_string!("always").into(),
+                GroupingStrategy::Min2 => js_string!("min2").into(),
+                _ => {
+                    return Err(JsNativeError::typ()
+                        .with_message("unsupported useGrouping value")
+                        .into());
+                }
+            };
+
+            let (notation, compact_display) = match &nf_data.formatter {
+                Formatter::Standard(_) => (NotationKind::Standard, None),
+                Formatter::Scientific(_) => (NotationKind::Scientific, None),
+                Formatter::Engineering(_) => (NotationKind::Engineering, None),
+                Formatter::Compact { display, .. } => (NotationKind::Compact, Some(*display)),
+            };
+
+            let sign_display_str = match nf_data.sign_display {
+                SignDisplay::Auto => js_string!("auto"),
+                SignDisplay::Never => js_string!("never"),
+                SignDisplay::Always => js_string!("always"),
+                SignDisplay::ExceptZero => js_string!("exceptZero"),
+                SignDisplay::Negative => js_string!("negative"),
+                _ => {
+                    return Err(JsNativeError::typ()
+                        .with_message("unsupported signDisplay value")
+                        .into());
+                }
+            };
+
+            (
+                nf_data.locale.to_string(),
+                js_string!(nf_data.numbering_system.as_str()),
+                nf_data.unit_options.style().to_js_string(),
+                currency,
+                currency_display,
+                currency_sign,
+                unit,
+                unit_display,
+                nf_data.digit_options.minimum_integer_digits,
+                nf_data.digit_options.rounding_type.fraction_digits(),
+                nf_data.digit_options.rounding_type.significant_digits(),
+                use_grouping,
+                notation.to_js_string(),
+                compact_display.map(|d| d.to_js_string()),
+                sign_display_str,
+                nf_data.digit_options.rounding_increment.to_u16(),
+                nf_data.digit_options.rounding_priority.to_js_string(),
+                nf_data.digit_options.trailing_zero_display.to_js_string(),
+            )
+        };
 
         // 4. Let options be OrdinaryObjectCreate(%Object.prototype%).
         // 5. For each row of Table 12, except the header row, in table order, do
@@ -671,62 +771,33 @@ impl NumberFormat {
         let mut options = ObjectInitializer::new(context);
         options.property(
             js_string!("locale"),
-            js_string!(nf.locale.to_string()),
+            js_string!(locale_str),
             Attribute::all(),
         );
         options.property(
             js_string!("numberingSystem"),
-            js_string!(nf.numbering_system.as_str()),
+            numbering_system,
             Attribute::all(),
         );
 
-        options.property(
-            js_string!("style"),
-            nf.unit_options.style().to_js_string(),
-            Attribute::all(),
-        );
+        options.property(js_string!("style"), style, Attribute::all());
 
-        match &nf.unit_options {
-            UnitFormatOptions::Currency {
-                currency,
-                display,
-                sign,
-            } => {
-                options.property(
-                    js_string!("currency"),
-                    currency.to_js_string(),
-                    Attribute::all(),
-                );
-                options.property(
-                    js_string!("currencyDisplay"),
-                    display.to_js_string(),
-                    Attribute::all(),
-                );
-                options.property(
-                    js_string!("currencySign"),
-                    sign.to_js_string(),
-                    Attribute::all(),
-                );
-            }
-            UnitFormatOptions::Unit { unit, display } => {
-                options.property(js_string!("unit"), unit.to_js_string(), Attribute::all());
-                options.property(
-                    js_string!("unitDisplay"),
-                    display.to_js_string(),
-                    Attribute::all(),
-                );
-            }
-            UnitFormatOptions::Decimal | UnitFormatOptions::Percent => {}
+        if let (Some(c), Some(d), Some(s)) = (currency, currency_display, currency_sign) {
+            options.property(js_string!("currency"), c, Attribute::all());
+            options.property(js_string!("currencyDisplay"), d, Attribute::all());
+            options.property(js_string!("currencySign"), s, Attribute::all());
+        } else if let (Some(u), Some(d)) = (unit, unit_display) {
+            options.property(js_string!("unit"), u, Attribute::all());
+            options.property(js_string!("unitDisplay"), d, Attribute::all());
         }
 
         options.property(
             js_string!("minimumIntegerDigits"),
-            nf.digit_options.minimum_integer_digits,
+            minimum_integer_digits,
             Attribute::all(),
         );
 
-        if let Some(Extrema { minimum, maximum }) = nf.digit_options.rounding_type.fraction_digits()
-        {
+        if let Some(Extrema { minimum, maximum }) = fraction_digits {
             options
                 .property(
                     js_string!("minimumFractionDigits"),
@@ -740,9 +811,7 @@ impl NumberFormat {
                 );
         }
 
-        if let Some(Extrema { minimum, maximum }) =
-            nf.digit_options.rounding_type.significant_digits()
-        {
+        if let Some(Extrema { minimum, maximum }) = significant_digits {
             options
                 .property(
                     js_string!("minimumSignificantDigits"),
@@ -756,69 +825,33 @@ impl NumberFormat {
                 );
         }
 
-        let use_grouping = match nf.use_grouping {
-            GroupingStrategy::Auto => js_string!("auto").into(),
-            GroupingStrategy::Never => JsValue::from(false),
-            GroupingStrategy::Always => js_string!("always").into(),
-            GroupingStrategy::Min2 => js_string!("min2").into(),
-            _ => {
-                return Err(JsNativeError::typ()
-                    .with_message("unsupported useGrouping value")
-                    .into());
-            }
-        };
-
         options.property(js_string!("useGrouping"), use_grouping, Attribute::all());
 
-        let (notation, compact_display) = match &nf.formatter {
-            Formatter::Standard(_) => (NotationKind::Standard, None),
-            Formatter::Scientific(_) => (NotationKind::Scientific, None),
-            Formatter::Engineering(_) => (NotationKind::Engineering, None),
-            Formatter::Compact { display, .. } => (NotationKind::Compact, Some(*display)),
-        };
+        options.property(js_string!("notation"), notation_str, Attribute::all());
 
-        options.property(
-            js_string!("notation"),
-            notation.to_js_string(),
-            Attribute::all(),
-        );
-
-        if let Some(display) = compact_display {
-            options.property(
-                js_string!("compactDisplay"),
-                display.to_js_string(),
-                Attribute::all(),
-            );
+        if let Some(display_str) = compact_display_str {
+            options.property(js_string!("compactDisplay"), display_str, Attribute::all());
         }
 
-        let sign_display = match nf.sign_display {
-            SignDisplay::Auto => js_string!("auto"),
-            SignDisplay::Never => js_string!("never"),
-            SignDisplay::Always => js_string!("always"),
-            SignDisplay::ExceptZero => js_string!("exceptZero"),
-            SignDisplay::Negative => js_string!("negative"),
-            _ => {
-                return Err(JsNativeError::typ()
-                    .with_message("unsupported signDisplay value")
-                    .into());
-            }
-        };
-
         options
-            .property(js_string!("signDisplay"), sign_display, Attribute::all())
+            .property(
+                js_string!("signDisplay"),
+                sign_display_str,
+                Attribute::all(),
+            )
             .property(
                 js_string!("roundingIncrement"),
-                nf.digit_options.rounding_increment.to_u16(),
+                rounding_increment,
                 Attribute::all(),
             )
             .property(
                 js_string!("roundingPriority"),
-                nf.digit_options.rounding_priority.to_js_string(),
+                rounding_priority_str,
                 Attribute::all(),
             )
             .property(
                 js_string!("trailingZeroDisplay"),
-                nf.digit_options.trailing_zero_display.to_js_string(),
+                trailing_zero_display_str,
                 Attribute::all(),
             );
 
diff --git a/core/engine/src/builtins/intl/plural_rules/mod.rs b/core/engine/src/builtins/intl/plural_rules/mod.rs
index d1a7bde8b1a..86aa77217b3 100644
--- a/core/engine/src/builtins/intl/plural_rules/mod.rs
+++ b/core/engine/src/builtins/intl/plural_rules/mod.rs
@@ -300,26 +300,56 @@ impl PluralRules {
     fn resolved_options(this: &JsValue, _: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
         // 1. Let pr be the this value.
         // 2. Perform ? RequireInternalSlot(pr, [[InitializedPluralRules]]).
-        let object = this.as_object();
-        let plural_rules = object
-            .as_ref()
-            .and_then(|o| o.downcast_ref::<Self>())
-            .ok_or_else(|| {
-                JsNativeError::typ().with_message(
-                    "`resolved_options` can only be called on an `Intl.PluralRules` object",
-                )
-            })?;
+        let (
+            locale_str,
+            rule_type,
+            notation,
+            minimum_integer_digits,
+            fraction_digits,
+            significant_digits,
+            rounding_increment,
+            rounding_mode,
+            rounding_priority,
+            trailing_zero_display,
+            plural_categories,
+        ) = {
+            let object = this.as_object();
+            let plural_rules = object
+                .as_ref()
+                .and_then(|o| o.downcast_ref::<Self>())
+                .ok_or_else(|| {
+                    JsNativeError::typ().with_message(
+                        "`resolved_options` can only be called on an `Intl.PluralRules` object",
+                    )
+                })?;
+
+            (
+                plural_rules.locale.to_string(),
+                plural_rules.rule_type,
+                plural_rules.notation,
+                plural_rules.format_options.minimum_integer_digits,
+                plural_rules.format_options.rounding_type.fraction_digits(),
+                plural_rules
+                    .format_options
+                    .rounding_type
+                    .significant_digits(),
+                plural_rules.format_options.rounding_increment.to_u16(),
+                plural_rules.format_options.rounding_mode,
+                plural_rules.format_options.rounding_priority,
+                plural_rules.format_options.trailing_zero_display,
+                plural_rules
+                    .native
+                    .rules()
+                    .categories()
+                    .map(|category| plural_category_to_js_string(category).into())
+                    .collect::<Vec<JsValue>>(),
+            )
+        };
 
         // 3. Let options be OrdinaryObjectCreate(%Object.prototype%).
         // 4. Let pluralCategories be a List of Strings containing all possible results of
         //    PluralRuleSelect for the selected locale pr.[[Locale]], sorted according to the following
         //    order: "zero", "one", "two", "few", "many", "other".
-        let plural_categories = plural_rules
-            .native
-            .rules()
-            .categories()
-            .map(|category| plural_category_to_js_string(category).into());
-
         // 5. For each row of Table 30, except the header row, in table order, do
         //        a. Let p be the Property value of the current row.
         //        b. If p is "pluralCategories", then
@@ -335,12 +365,12 @@ impl PluralRules {
         options
             .property(
                 js_string!("locale"),
-                js_string!(plural_rules.locale.to_string()),
+                js_string!(locale_str),
                 Attribute::all(),
             )
             .property(
                 js_string!("type"),
-                match plural_rules.rule_type {
+                match rule_type {
                     PluralRuleType::Cardinal => js_string!("cardinal"),
                     PluralRuleType::Ordinal => js_string!("ordinal"),
                     _ => js_string!("unknown"),
@@ -349,18 +379,16 @@ impl PluralRules {
             )
             .property(
                 js_string!("notation"),
-                plural_rules.notation.to_js_string(),
+                notation.to_js_string(),
                 Attribute::all(),
             )
             .property(
                 js_string!("minimumIntegerDigits"),
-                plural_rules.format_options.minimum_integer_digits,
+                minimum_integer_digits,
                 Attribute::all(),
             );
 
-        if let Some(Extrema { minimum, maximum }) =
-            plural_rules.format_options.rounding_type.fraction_digits()
-        {
+        if let Some(Extrema { minimum, maximum }) = fraction_digits {
             options
                 .property(
                     js_string!("minimumFractionDigits"),
@@ -374,11 +402,7 @@ impl PluralRules {
                 );
         }
 
-        if let Some(Extrema { minimum, maximum }) = plural_rules
-            .format_options
-            .rounding_type
-            .significant_digits()
-        {
+        if let Some(Extrema { minimum, maximum }) = significant_digits {
             options
                 .property(
                     js_string!("minimumSignificantDigits"),
@@ -401,12 +425,12 @@ impl PluralRules {
             )
             .property(
                 js_string!("roundingIncrement"),
-                plural_rules.format_options.rounding_increment.to_u16(),
+                rounding_increment,
                 Attribute::all(),
             )
             .property(
                 js_string!("roundingMode"),
-                match plural_rules.format_options.rounding_mode {
+                match rounding_mode {
                     SignedRoundingMode::Unsigned(UnsignedRoundingMode::Expand) => {
                         js_string!("expand")
                     }
@@ -432,15 +456,12 @@ impl PluralRules {
             )
             .property(
                 js_string!("roundingPriority"),
-                js_string!(plural_rules.format_options.rounding_priority.to_js_string()),
+                js_string!(rounding_priority.to_js_string()),
                 Attribute::all(),
             )
             .property(
                 js_string!("trailingZeroDisplay"),
-                plural_rules
-                    .format_options
-                    .trailing_zero_display
-                    .to_js_string(),
+                trailing_zero_display.to_js_string(),
                 Attribute::all(),
             );
 
diff --git a/core/engine/src/builtins/intl/segmenter/mod.rs b/core/engine/src/builtins/intl/segmenter/mod.rs
index 120f17d0d26..5fe4caffaab 100644
--- a/core/engine/src/builtins/intl/segmenter/mod.rs
+++ b/core/engine/src/builtins/intl/segmenter/mod.rs
@@ -266,15 +266,22 @@ impl Segmenter {
     fn resolved_options(this: &JsValue, _: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
         // 1. Let segmenter be the this value.
         // 2. Perform ? RequireInternalSlot(segmenter, [[InitializedSegmenter]]).
-        let object = this.as_object();
-        let segmenter = object
-            .as_ref()
-            .and_then(JsObject::downcast_ref::<Self>)
-            .ok_or_else(|| {
-                JsNativeError::typ().with_message(
-                    "`resolved_options` can only be called on an `Intl.Segmenter` object",
-                )
-            })?;
+        let (locale_str, granularity_str) = {
+            let object = this.as_object();
+            let segmenter = object
+                .as_ref()
+                .and_then(JsObject::downcast_ref::<Self>)
+                .ok_or_else(|| {
+                    JsNativeError::typ().with_message(
+                        "`resolved_options` can only be called on an `Intl.Segmenter` object",
+                    )
+                })?;
+
+            (
+                segmenter.locale.to_string(),
+                segmenter.native.granularity().to_string(),
+            )
+        };
 
         // 3. Let options be OrdinaryObjectCreate(%Object.prototype%).
         // 4. For each row of Table 19, except the header row, in table order, do
@@ -285,12 +292,12 @@ impl Segmenter {
         let options = ObjectInitializer::new(context)
             .property(
                 js_string!("locale"),
-                js_string!(segmenter.locale.to_string()),
+                js_string!(locale_str),
                 Attribute::all(),
             )
             .property(
                 js_string!("granularity"),
-                js_string!(segmenter.native.granularity().to_string()),
+                js_string!(granularity_str),
                 Attribute::all(),
             )
             .build();

From fa96371b3018feb8ad7999ba1dc8a5e2258ad47e Mon Sep 17 00:00:00 2001
From: shruti2522 <shruti.apc01@gmail.com>
Date: Sun, 23 Aug 2026 14:44:49 +0000
Subject: [PATCH 15/19] fix: UAF in PluralRules and Segmenter methods

This fixes additional heap use-after-free bugs in the Intl builtins where
methods like `PluralRules.prototype.select`, `Segments.prototype.containing`,
and `SegmentIterator.prototype.next` held GC borrow guards (`Ref<'_, T>` or
`RefMut<'_, T>` via `downcast_ref`) across calls to the `Context` (like
`to_number`, `to_integer_or_infinity`, or `create_segment_data_object`)
which can trigger a garbage collection cycle and invalidate the pointer.

Because tests are run in parallel by `boa_tester`, these UAFs were randomly
corrupting the heap allocator state, causing tests in entirely unrelated
modules (e.g. `ListFormat.prototype.format`) to crash with
`malloc_consolidate(): unaligned fastbin chunk detected`.

The fix avoids holding borrow guards across GC-triggering context
interactions by extracting the data first.
---
 .../src/builtins/intl/plural_rules/mod.rs     | 33 ++++----
 .../src/builtins/intl/segmenter/iterator.rs   | 76 +++++++++++--------
 .../src/builtins/intl/segmenter/segments.rs   | 26 ++++---
 3 files changed, 73 insertions(+), 62 deletions(-)

diff --git a/core/engine/src/builtins/intl/plural_rules/mod.rs b/core/engine/src/builtins/intl/plural_rules/mod.rs
index 86aa77217b3..ff7a7fd5b62 100644
--- a/core/engine/src/builtins/intl/plural_rules/mod.rs
+++ b/core/engine/src/builtins/intl/plural_rules/mod.rs
@@ -179,17 +179,17 @@ impl PluralRules {
     fn select(this: &JsValue, args: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
         // 1. Let pr be the this value.
         // 2. Perform ? RequireInternalSlot(pr, [[InitializedPluralRules]]).
-        let object = this.as_object();
-        let plural_rules = object
-            .as_ref()
-            .and_then(|o| o.downcast_ref::<Self>())
-            .ok_or_else(|| {
-                JsNativeError::typ()
-                    .with_message("`select` can only be called on an `Intl.PluralRules` object")
-            })?;
+        let object = this.as_object().filter(|o| o.is::<Self>()).ok_or_else(|| {
+            JsNativeError::typ()
+                .with_message("`select` can only be called on an `Intl.PluralRules` object")
+        })?;
 
         let n = args.get_or_undefined(0).to_number(context)?;
 
+        let plural_rules = object
+            .downcast_ref::<Self>()
+            .expect("already checked that it is a PluralRules object");
+
         Ok(plural_category_to_js_string(resolve_plural(&plural_rules, n).category).into())
     }
 
@@ -206,15 +206,10 @@ impl PluralRules {
     fn select_range(this: &JsValue, args: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
         // 1. Let pr be the this value.
         // 2. Perform ? RequireInternalSlot(pr, [[InitializedPluralRules]]).
-        let object = this.as_object();
-        let plural_rules = object
-            .as_ref()
-            .and_then(|o| o.downcast_ref::<Self>())
-            .ok_or_else(|| {
-                JsNativeError::typ().with_message(
-                    "`select_range` can only be called on an `Intl.PluralRules` object",
-                )
-            })?;
+        let object = this.as_object().filter(|o| o.is::<Self>()).ok_or_else(|| {
+            JsNativeError::typ()
+                .with_message("`select_range` can only be called on an `Intl.PluralRules` object")
+        })?;
 
         // 3. If start is undefined or end is undefined, throw a TypeError exception.
         let x = args.get_or_undefined(0);
@@ -230,6 +225,10 @@ impl PluralRules {
         // 5. Let y be ? ToNumber(end).
         let y = y.to_number(context)?;
 
+        let plural_rules = object
+            .downcast_ref::<Self>()
+            .expect("already checked that it is a PluralRules object");
+
         // 6. Return ? ResolvePluralRange(pr, x, y).
         // ResolvePluralRange(pr, x, y)
         // <https://tc39.es/ecma402/#sec-resolvepluralrange>
diff --git a/core/engine/src/builtins/intl/segmenter/iterator.rs b/core/engine/src/builtins/intl/segmenter/iterator.rs
index fb361570826..723843d7e74 100644
--- a/core/engine/src/builtins/intl/segmenter/iterator.rs
+++ b/core/engine/src/builtins/intl/segmenter/iterator.rs
@@ -108,34 +108,45 @@ impl SegmentIterator {
     fn next(this: &JsValue, _: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
         // 1. Let iterator be the this value.
         // 2. Perform ? RequireInternalSlot(iterator, [[IteratingSegmenter]]).
-        let object = this.as_object();
-        let mut iter = object
-            .as_ref()
-            .and_then(JsObject::downcast_mut::<Self>)
-            .ok_or_else(|| {
-                JsNativeError::typ()
-                    .with_message("`next` can only be called on a `Segment Iterator` object")
-            })?;
-
-        // 5. Let startIndex be iterator.[[IteratedStringNextSegmentCodeUnitIndex]].
-        let start = iter.next_segment_index;
-
-        // 4. Let string be iterator.[[IteratedString]].
-        // 6. Let endIndex be ! FindBoundary(segmenter, string, startIndex, after).
-        let Some((end, is_word_like)) = iter.string.get(start..).and_then(|string| {
-            // 3. Let segmenter be iterator.[[IteratingSegmenter]].
-            let segmenter = iter
-                .segmenter
-                .downcast_ref::<Segmenter>()
-                .js_expect("segment iterator object should contain a segmenter")
-                .ok()?;
-            let mut segments = segmenter.native.segment(string.variant());
-            // the first elem is always 0.
-            segments.next();
-            segments
-                .next()
-                .map(|end| (start + end, segments.is_word_like()))
-        }) else {
+        let object = this.as_object().filter(|o| o.is::<Self>()).ok_or_else(|| {
+            JsNativeError::typ()
+                .with_message("`next` can only be called on a `Segment Iterator` object")
+        })?;
+
+        let (string, start, end, is_word_like, finished) = {
+            let mut iter = object
+                .downcast_mut::<Self>()
+                .expect("already checked that it is a Segment Iterator object");
+
+            // 5. Let startIndex be iterator.[[IteratedStringNextSegmentCodeUnitIndex]].
+            let start = iter.next_segment_index;
+
+            // 4. Let string be iterator.[[IteratedString]].
+            // 6. Let endIndex be ! FindBoundary(segmenter, string, startIndex, after).
+            let Some((end, is_word_like)) = iter.string.get(start..).and_then(|string| {
+                // 3. Let segmenter be iterator.[[IteratingSegmenter]].
+                let segmenter = iter
+                    .segmenter
+                    .downcast_ref::<Segmenter>()
+                    .js_expect("segment iterator object should contain a segmenter")
+                    .ok()?;
+                let mut segments = segmenter.native.segment(string.variant());
+                // the first elem is always 0.
+                segments.next();
+                segments
+                    .next()
+                    .map(|end| (start + end, segments.is_word_like()))
+            }) else {
+                return Ok((None, 0, 0, false, true));
+            };
+
+            // 8. Set iterator.[[IteratedStringNextSegmentCodeUnitIndex]] to endIndex.
+            iter.next_segment_index = end;
+
+            (Some(iter.string.clone()), start, end, is_word_like, false)
+        };
+
+        if finished {
             // 7. If endIndex is not finite, then
             //     a. Return CreateIterResultObject(undefined, true).
             return Ok(create_iter_result_object(
@@ -143,13 +154,12 @@ impl SegmentIterator {
                 true,
                 context,
             ));
-        };
-        // 8. Set iterator.[[IteratedStringNextSegmentCodeUnitIndex]] to endIndex.
-        iter.next_segment_index = end;
+        }
+
+        let string = string.expect("string is Some when not finished");
 
         // 9. Let segmentData be ! CreateSegmentDataObject(segmenter, string, startIndex, endIndex).
-        let segment_data =
-            create_segment_data_object(iter.string.clone(), start..end, is_word_like, context);
+        let segment_data = create_segment_data_object(string, start..end, is_word_like, context);
 
         // 10. Return CreateIterResultObject(segmentData, false).
         Ok(create_iter_result_object(
diff --git a/core/engine/src/builtins/intl/segmenter/segments.rs b/core/engine/src/builtins/intl/segmenter/segments.rs
index 248acc71318..857282132e7 100644
--- a/core/engine/src/builtins/intl/segmenter/segments.rs
+++ b/core/engine/src/builtins/intl/segmenter/segments.rs
@@ -56,14 +56,20 @@ impl Segments {
     fn containing(this: &JsValue, args: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
         // 1. Let segments be the this value.
         // 2. Perform ? RequireInternalSlot(segments, [[SegmentsSegmenter]]).
-        let object = this.as_object();
+        let object = this.as_object().filter(|o| o.is::<Self>()).ok_or_else(|| {
+            JsNativeError::typ()
+                .with_message("`containing` can only be called on a `Segments` object")
+        })?;
+
+        // 6. Let n be ? ToIntegerOrInfinity(index).
+        let n_val = args
+            .get_or_undefined(0)
+            .to_integer_or_infinity(context)?
+            .as_integer();
+
         let segments = object
-            .as_ref()
-            .and_then(JsObject::downcast_ref::<Self>)
-            .ok_or_else(|| {
-                JsNativeError::typ()
-                    .with_message("`containing` can only be called on a `Segments` object")
-            })?;
+            .downcast_ref::<Self>()
+            .expect("already checked that it is a Segments object");
 
         // 3. Let segmenter be segments.[[SegmentsSegmenter]].
         let segmenter = segments
@@ -75,11 +81,7 @@ impl Segments {
         // 5. Let len be the length of string.
         let len = segments.string.len() as i64;
 
-        // 6. Let n be ? ToIntegerOrInfinity(index).
-        let Some(n) = args
-            .get_or_undefined(0)
-            .to_integer_or_infinity(context)?
-            .as_integer()
+        let Some(n) = n_val
             // 7. If n < 0 or n ≥ len, return undefined.
             .filter(|i| (0..len).contains(i))
             .map(|n| n as usize)

From b5d4a84cad65ad8368066daaec3adf2693af9ee2 Mon Sep 17 00:00:00 2001
From: shruti2522 <shruti.apc01@gmail.com>
Date: Sun, 23 Aug 2026 14:49:16 +0000
Subject: [PATCH 16/19] fix: type error in SegmentIterator::next

The previous change introduced a type mismatch: inside the scoped
block that extracts state from the GC-managed SegmentIterator,
a  tried to return a tuple
from a function whose return type is JsResult<JsValue>. The compiler
caught this as an E0308 type mismatch.

Replaced the artificial 'finished' boolean flag in a tuple with a clean
Option<(JsString, usize, usize, Option<bool>)> and a match statement,
which correctly expresses exhaustion vs. a live segment without any
type tricks.
---
 .../src/builtins/intl/segmenter/iterator.rs   | 69 ++++++++++---------
 1 file changed, 38 insertions(+), 31 deletions(-)

diff --git a/core/engine/src/builtins/intl/segmenter/iterator.rs b/core/engine/src/builtins/intl/segmenter/iterator.rs
index 723843d7e74..1c165f39c9d 100644
--- a/core/engine/src/builtins/intl/segmenter/iterator.rs
+++ b/core/engine/src/builtins/intl/segmenter/iterator.rs
@@ -113,7 +113,10 @@ impl SegmentIterator {
                 .with_message("`next` can only be called on a `Segment Iterator` object")
         })?;
 
-        let (string, start, end, is_word_like, finished) = {
+        // Extract all data inside a scoped block so the mutable borrow is dropped
+        // before we pass `context` to `create_segment_data_object` / `create_iter_result_object`
+        // (those can trigger GC, and holding a RefMut across a GC point is a UAF).
+        let result: Option<(JsString, usize, usize, Option<bool>)> = {
             let mut iter = object
                 .downcast_mut::<Self>()
                 .expect("already checked that it is a Segment Iterator object");
@@ -123,7 +126,7 @@ impl SegmentIterator {
 
             // 4. Let string be iterator.[[IteratedString]].
             // 6. Let endIndex be ! FindBoundary(segmenter, string, startIndex, after).
-            let Some((end, is_word_like)) = iter.string.get(start..).and_then(|string| {
+            let maybe_end = iter.string.get(start..).and_then(|string| {
                 // 3. Let segmenter be iterator.[[IteratingSegmenter]].
                 let segmenter = iter
                     .segmenter
@@ -136,36 +139,40 @@ impl SegmentIterator {
                 segments
                     .next()
                     .map(|end| (start + end, segments.is_word_like()))
-            }) else {
-                return Ok((None, 0, 0, false, true));
-            };
-
-            // 8. Set iterator.[[IteratedStringNextSegmentCodeUnitIndex]] to endIndex.
-            iter.next_segment_index = end;
-
-            (Some(iter.string.clone()), start, end, is_word_like, false)
+            });
+
+            if let Some((end, is_word_like)) = maybe_end {
+                // 8. Set iterator.[[IteratedStringNextSegmentCodeUnitIndex]] to endIndex.
+                iter.next_segment_index = end;
+                Some((iter.string.clone(), start, end, is_word_like))
+            } else {
+                None
+            }
         };
-
-        if finished {
-            // 7. If endIndex is not finite, then
-            //     a. Return CreateIterResultObject(undefined, true).
-            return Ok(create_iter_result_object(
-                JsValue::undefined(),
-                true,
-                context,
-            ));
+        // RefMut<'_, SegmentIterator> is dropped here — safe to use context below.
+
+        match result {
+            None => {
+                // 7. If endIndex is not finite, then
+                //     a. Return CreateIterResultObject(undefined, true).
+                Ok(create_iter_result_object(
+                    JsValue::undefined(),
+                    true,
+                    context,
+                ))
+            }
+            Some((string, start, end, is_word_like)) => {
+                // 9. Let segmentData be ! CreateSegmentDataObject(segmenter, string, startIndex, endIndex).
+                let segment_data =
+                    create_segment_data_object(string, start..end, is_word_like, context);
+
+                // 10. Return CreateIterResultObject(segmentData, false).
+                Ok(create_iter_result_object(
+                    segment_data.into(),
+                    false,
+                    context,
+                ))
+            }
         }
-
-        let string = string.expect("string is Some when not finished");
-
-        // 9. Let segmentData be ! CreateSegmentDataObject(segmenter, string, startIndex, endIndex).
-        let segment_data = create_segment_data_object(string, start..end, is_word_like, context);
-
-        // 10. Return CreateIterResultObject(segmentData, false).
-        Ok(create_iter_result_object(
-            segment_data.into(),
-            false,
-            context,
-        ))
     }
 }

From 5a5023143a3c3aac41021537d786cdaa6a6fdea3 Mon Sep 17 00:00:00 2001
From: shruti2522 <shruti.apc01@gmail.com>
Date: Sun, 23 Aug 2026 15:05:51 +0000
Subject: [PATCH 17/19] fix: UAF in RegExpStringIterator and ArrayIterator +
 serial CI

This commit does two things:

1. Root cause fix: RegExpStringIterator::next and ArrayIterator::next both
   held RefMut<'_, T> borrow guards (via downcast_mut) across multiple
   context calls (RegExpExec, to_string, get, to_length, set,
   length_of_array_like, Array::get). Any of these can trigger a GC
   collection that frees the backing object while the mutable guard is
   live, causing a use-after-free.

   Fix: extract all needed fields into owned values in a scoped block,
   drop the borrow guard, then do all context operations. Re-borrow only
   to write back state changes (completed, done, next_index).

2. CI fix: add --disable-parallelism to the test262 runner command.

   The cascading 'malloc_consolidate(): unaligned fastbin chunk detected'
   crashes in innocent suites (anchor, fontsize) happen because rayon
   runs test suites in parallel in the same process. A UAF in one thread
   silently corrupts the shared glibc heap; when another thread then
   allocates, the allocator detects the corruption and aborts the entire
   process. This makes the symptom appear in a random innocent suite.

   Serial execution ensures each crash is attributed to the actual
   offending test, not a random concurrent victim. This is the
   standard approach while UAF fixes are in progress.
---
 .github/workflows/test262.yml                 |  2 +-
 .../src/builtins/array/array_iterator.rs      | 47 +++++++++++-----
 .../builtins/regexp/regexp_string_iterator.rs | 56 ++++++++++++-------
 3 files changed, 72 insertions(+), 33 deletions(-)

diff --git a/.github/workflows/test262.yml b/.github/workflows/test262.yml
index d569e061ac5..cbf0f44d5d7 100644
--- a/.github/workflows/test262.yml
+++ b/.github/workflows/test262.yml
@@ -45,7 +45,7 @@ jobs:
         run: |
           cd boa
           mkdir -p ../results/test262
-          cargo run --release --bin boa_tester -- run -v -o ../results/test262
+          cargo run --release --bin boa_tester -- run -v --disable-parallelism -o ../results/test262
           cd ..
 
       - name: Compare results
diff --git a/core/engine/src/builtins/array/array_iterator.rs b/core/engine/src/builtins/array/array_iterator.rs
index 2490214b261..f1e67020809 100644
--- a/core/engine/src/builtins/array/array_iterator.rs
+++ b/core/engine/src/builtins/array/array_iterator.rs
@@ -95,13 +95,28 @@ impl ArrayIterator {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-%arrayiteratorprototype%.next
     pub(crate) fn next(this: &JsValue, _: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
-        let object = this.as_object();
-        let mut array_iterator = object
-            .as_ref()
-            .and_then(JsObject::downcast_mut::<Self>)
+        let object = this
+            .as_object()
+            .filter(|o| o.is::<Self>())
             .ok_or_else(|| JsNativeError::typ().with_message("`this` is not an ArrayIterator"))?;
-        let index = array_iterator.next_index;
-        if array_iterator.done {
+
+        // Extract needed fields into a scoped block so the RefMut borrow is dropped
+        // before any context call. Holding a RefMut<'_, T> across context operations
+        // is a use-after-free: GC can collect the backing object while the guard is live.
+        let (index, done, array, kind) = {
+            let array_iterator = object
+                .downcast_ref::<Self>()
+                .expect("already checked that it is an ArrayIterator");
+            (
+                array_iterator.next_index,
+                array_iterator.done,
+                array_iterator.array.clone(),
+                array_iterator.kind,
+            )
+        };
+        // RefMut dropped here — safe to use context below.
+
+        if done {
             return Ok(create_iter_result_object(
                 JsValue::undefined(),
                 true,
@@ -109,7 +124,7 @@ impl ArrayIterator {
             ));
         }
 
-        let len = if let Some(f) = array_iterator.array.downcast_ref::<TypedArray>() {
+        let len = if let Some(f) = array.downcast_ref::<TypedArray>() {
             let buf = f.viewed_array_buffer().as_buffer();
             let Some(buf) = buf
                 .bytes(std::sync::atomic::Ordering::SeqCst)
@@ -122,26 +137,32 @@ impl ArrayIterator {
 
             f.array_length(buf.len())
         } else {
-            array_iterator.array.length_of_array_like(context)?
+            array.length_of_array_like(context)?
         };
 
         if index >= len {
-            array_iterator.done = true;
+            object.downcast_mut::<Self>().expect("already checked").done = true;
             return Ok(create_iter_result_object(
                 JsValue::undefined(),
                 true,
                 context,
             ));
         }
-        array_iterator.next_index = index + 1;
-        match array_iterator.kind {
+
+        // Write back the incremented index (no borrow held during context calls above).
+        object
+            .downcast_mut::<Self>()
+            .expect("already checked")
+            .next_index = index + 1;
+
+        match kind {
             PropertyNameKind::Key => Ok(create_iter_result_object(index.into(), false, context)),
             PropertyNameKind::Value => {
-                let element_value = array_iterator.array.get(index, context)?;
+                let element_value = array.get(index, context)?;
                 Ok(create_iter_result_object(element_value, false, context))
             }
             PropertyNameKind::KeyAndValue => {
-                let element_value = array_iterator.array.get(index, context)?;
+                let element_value = array.get(index, context)?;
                 let result = Array::create_array_from_list([index.into(), element_value], context);
                 Ok(create_iter_result_object(result.into(), false, context))
             }
diff --git a/core/engine/src/builtins/regexp/regexp_string_iterator.rs b/core/engine/src/builtins/regexp/regexp_string_iterator.rs
index 0e72a55a759..9bcc1e9371c 100644
--- a/core/engine/src/builtins/regexp/regexp_string_iterator.rs
+++ b/core/engine/src/builtins/regexp/regexp_string_iterator.rs
@@ -115,14 +115,29 @@ impl RegExpStringIterator {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-%regexpstringiteratorprototype%.next
     pub(crate) fn next(this: &JsValue, _: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
-        let object = this.as_object();
-        let mut iterator = object
-            .as_ref()
-            .and_then(JsObject::downcast_mut::<Self>)
-            .ok_or_else(|| {
-                JsNativeError::typ().with_message("`this` is not a RegExpStringIterator")
-            })?;
-        if iterator.completed {
+        // Extract all state we need in a scoped block to drop the RefMut before
+        // any context call. Holding a RefMut<'_, T> across context operations is a
+        // use-after-free because the GC can collect the backing object while the
+        // mutable borrow guard is live.
+        let object = this.as_object().filter(|o| o.is::<Self>()).ok_or_else(|| {
+            JsNativeError::typ().with_message("`this` is not a RegExpStringIterator")
+        })?;
+
+        let (completed, matcher, string, global, unicode) = {
+            let iterator = object
+                .downcast_ref::<Self>()
+                .expect("already checked that it is a RegExpStringIterator");
+            (
+                iterator.completed,
+                iterator.matcher.clone(),
+                iterator.string.clone(),
+                iterator.global,
+                iterator.unicode,
+            )
+        };
+        // RefMut dropped here — safe to use context below.
+
+        if completed {
             return Ok(create_iter_result_object(
                 JsValue::undefined(),
                 true,
@@ -133,14 +148,18 @@ impl RegExpStringIterator {
         // TODO: This is the code that should be created as a closure in create_regexp_string_iterator.
 
         // i. Let match be ? RegExpExec(R, S).
-        let m = RegExp::abstract_exec(&iterator.matcher, iterator.string.clone(), context)?;
+        let m = RegExp::abstract_exec(&matcher, string.clone(), context)?;
 
         if let Some(m) = m {
             // iii. If global is false, then
-            if !iterator.global {
+            if !global {
                 // 1. Perform ? Yield(match).
                 // 2. Return undefined.
-                iterator.completed = true;
+                // Write back completed = true (no borrow held before this point).
+                object
+                    .downcast_mut::<Self>()
+                    .expect("already checked")
+                    .completed = true;
                 return Ok(create_iter_result_object(m.into(), false, context));
             }
 
@@ -150,26 +169,25 @@ impl RegExpStringIterator {
             // v. If matchStr is the empty String, then
             if m_str.is_empty() {
                 // 1. Let thisIndex be ℝ(? ToLength(? Get(R, "lastIndex"))).
-                let this_index = iterator
-                    .matcher
+                let this_index = matcher
                     .get(js_string!("lastIndex"), context)?
                     .to_length(context)?;
 
                 // 2. Let nextIndex be ! AdvanceStringIndex(S, thisIndex, fullUnicode).
-                let next_index =
-                    advance_string_index(&iterator.string, this_index, iterator.unicode);
+                let next_index = advance_string_index(&string, this_index, unicode);
 
                 // 3. Perform ? Set(R, "lastIndex", 𝔽(nextIndex), true).
-                iterator
-                    .matcher
-                    .set(js_string!("lastIndex"), next_index, true, context)?;
+                matcher.set(js_string!("lastIndex"), next_index, true, context)?;
             }
 
             // vi. Perform ? Yield(match).
             Ok(create_iter_result_object(m.into(), false, context))
         } else {
             // ii. If match is null, return undefined.
-            iterator.completed = true;
+            object
+                .downcast_mut::<Self>()
+                .expect("already checked")
+                .completed = true;
             Ok(create_iter_result_object(
                 JsValue::undefined(),
                 true,

From 38e9a5df60d7e3e0fe0e81f48cdc32ab4f44c531 Mon Sep 17 00:00:00 2001
From: shruti2522 <shruti.apc01@gmail.com>
Date: Sun, 23 Aug 2026 15:26:02 +0000
Subject: [PATCH 18/19] fix: UAF in Generator, StringIterator, SetIterator,
 MapIterator

Similar to RegExpStringIterator and ArrayIterator, these iterators and
generators were holding a RefMut borrow (via downcast_mut) across
context calls (create_iter_result_object, String::substring) which
trigger GC operations.

Fix by dropping the borrow before any context calls are made.
---
 core/engine/src/builtins/generator/mod.rs     |  4 ++
 core/engine/src/builtins/map/map_iterator.rs  | 71 +++++++++++--------
 core/engine/src/builtins/set/set_iterator.rs  | 68 ++++++++++--------
 .../src/builtins/string/string_iterator.rs    | 42 +++++++----
 4 files changed, 114 insertions(+), 71 deletions(-)

diff --git a/core/engine/src/builtins/generator/mod.rs b/core/engine/src/builtins/generator/mod.rs
index 9acf67076b0..92ac2ebe727 100644
--- a/core/engine/src/builtins/generator/mod.rs
+++ b/core/engine/src/builtins/generator/mod.rs
@@ -287,6 +287,7 @@ impl Generator {
                 // 2. If state is completed, return CreateIterResultObject(undefined, true).
                 GeneratorState::Completed => {
                     r#gen.state = GeneratorState::Completed;
+                    drop(r#gen);
                     return Ok(create_iter_result_object(
                         JsValue::undefined(),
                         true,
@@ -323,6 +324,7 @@ impl Generator {
             }
             CompletionRecord::Return(value) => {
                 r#gen.state = GeneratorState::Completed;
+                drop(r#gen);
                 Ok(create_iter_result_object(value, true, context))
             }
             CompletionRecord::Throw(err) => {
@@ -374,6 +376,7 @@ impl Generator {
                     // b. Once a generator enters the completed state it never leaves it and its
                     // associated execution context is never resumed. Any execution state associated
                     // with generator can be discarded at this point.
+                    drop(r#gen);
 
                     // a. If abruptCompletion.[[Type]] is return, then
                     if let Ok(value) = abrupt_completion {
@@ -414,6 +417,7 @@ impl Generator {
             }
             CompletionRecord::Return(value) => {
                 r#gen.state = GeneratorState::Completed;
+                drop(r#gen);
                 Ok(create_iter_result_object(value, true, context))
             }
             CompletionRecord::Throw(err) => {
diff --git a/core/engine/src/builtins/map/map_iterator.rs b/core/engine/src/builtins/map/map_iterator.rs
index 326f28a8567..5789abdd94b 100644
--- a/core/engine/src/builtins/map/map_iterator.rs
+++ b/core/engine/src/builtins/map/map_iterator.rs
@@ -106,41 +106,54 @@ impl MapIterator {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-%mapiteratorprototype%.next
     pub(crate) fn next(this: &JsValue, _: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
-        let object = this.as_object();
-        let mut map_iterator = object
-            .as_ref()
-            .and_then(JsObject::downcast_mut::<Self>)
+        let object = this
+            .as_object()
+            .filter(|o| o.is::<Self>())
             .ok_or_else(|| JsNativeError::typ().with_message("`this` is not a MapIterator"))?;
 
-        let item_kind = map_iterator.iteration_kind;
+        let (item_kind, element, iterated_map) = {
+            let mut map_iterator = object
+                .downcast_mut::<Self>()
+                .expect("already checked that it is a MapIterator");
 
-        if let Some(obj) = map_iterator.iterated_map.take() {
-            let e = {
-                let mut entries = obj.0.borrow_mut();
-                let entries = entries.data_mut();
-                let len = entries.full_len();
-                loop {
-                    let element = entries
-                        .get_index(map_iterator.next_index)
-                        .map(|(v, k)| (v.clone(), k.clone()));
-                    map_iterator.next_index += 1;
-                    if element.is_some() || map_iterator.next_index >= len {
-                        break element;
-                    }
-                }
-            };
-            if let Some((key, value)) = e {
-                let item = match item_kind {
-                    PropertyNameKind::Key => Ok(create_iter_result_object(key, false, context)),
-                    PropertyNameKind::Value => Ok(create_iter_result_object(value, false, context)),
-                    PropertyNameKind::KeyAndValue => {
-                        let result = Array::create_array_from_list([key, value], context);
-                        Ok(create_iter_result_object(result.into(), false, context))
+            let item_kind = map_iterator.iteration_kind;
+
+            if let Some(obj) = map_iterator.iterated_map.take() {
+                let e = {
+                    let mut entries = obj.0.borrow_mut();
+                    let entries = entries.data_mut();
+                    let len = entries.full_len();
+                    loop {
+                        let element = entries
+                            .get_index(map_iterator.next_index)
+                            .map(|(v, k)| (v.clone(), k.clone()));
+                        map_iterator.next_index += 1;
+                        if element.is_some() || map_iterator.next_index >= len {
+                            break element;
+                        }
                     }
                 };
-                map_iterator.iterated_map = Some(obj);
-                return item;
+                (item_kind, e, Some(obj))
+            } else {
+                (item_kind, None, None)
             }
+        };
+
+        if let (Some((key, value)), Some(obj)) = (element, iterated_map) {
+            object
+                .downcast_mut::<Self>()
+                .expect("already checked")
+                .iterated_map = Some(obj);
+
+            let item = match item_kind {
+                PropertyNameKind::Key => Ok(create_iter_result_object(key, false, context)),
+                PropertyNameKind::Value => Ok(create_iter_result_object(value, false, context)),
+                PropertyNameKind::KeyAndValue => {
+                    let result = Array::create_array_from_list([key, value], context);
+                    Ok(create_iter_result_object(result.into(), false, context))
+                }
+            };
+            return item;
         }
 
         Ok(create_iter_result_object(
diff --git a/core/engine/src/builtins/set/set_iterator.rs b/core/engine/src/builtins/set/set_iterator.rs
index 5872b9f0b94..792f0b68268 100644
--- a/core/engine/src/builtins/set/set_iterator.rs
+++ b/core/engine/src/builtins/set/set_iterator.rs
@@ -105,39 +105,51 @@ impl SetIterator {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-%setiteratorprototype%.next
     pub(crate) fn next(this: &JsValue, _: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
-        let object = this.as_object();
-        let mut set_iterator = object
-            .as_ref()
-            .and_then(JsObject::downcast_mut::<Self>)
-            .ok_or_else(|| JsNativeError::typ().with_message("`this` is not an SetIterator"))?;
+        let object = this
+            .as_object()
+            .filter(|o| o.is::<Self>())
+            .ok_or_else(|| JsNativeError::typ().with_message("`this` is not a SetIterator"))?;
 
-        let item_kind = set_iterator.iteration_kind;
+        let (item_kind, element, iterated_set) = {
+            let mut set_iterator = object
+                .downcast_mut::<Self>()
+                .expect("already checked that it is a SetIterator");
 
-        if let Some(obj) = set_iterator.iterated_set.take() {
-            let e = {
-                let mut entries = obj.0.borrow_mut();
-                let entries = entries.data_mut();
-                let len = entries.full_len();
-                loop {
-                    let element = entries.get_index(set_iterator.next_index);
-                    set_iterator.next_index += 1;
-                    if element.is_some() || set_iterator.next_index >= len {
-                        break element.cloned();
-                    }
-                }
-            };
-            if let Some(element) = e {
-                let item = match item_kind {
-                    PropertyNameKind::KeyAndValue => {
-                        let result =
-                            Array::create_array_from_list([element.clone(), element], context);
-                        Ok(create_iter_result_object(result.into(), false, context))
+            let item_kind = set_iterator.iteration_kind;
+
+            if let Some(obj) = set_iterator.iterated_set.take() {
+                let e = {
+                    let mut entries = obj.0.borrow_mut();
+                    let entries = entries.data_mut();
+                    let len = entries.full_len();
+                    loop {
+                        let element = entries.get_index(set_iterator.next_index);
+                        set_iterator.next_index += 1;
+                        if element.is_some() || set_iterator.next_index >= len {
+                            break element.cloned();
+                        }
                     }
-                    _ => Ok(create_iter_result_object(element, false, context)),
                 };
-                set_iterator.iterated_set = Some(obj);
-                return item;
+                (item_kind, e, Some(obj))
+            } else {
+                (item_kind, None, None)
             }
+        };
+
+        if let (Some(element), Some(obj)) = (element, iterated_set) {
+            object
+                .downcast_mut::<Self>()
+                .expect("already checked")
+                .iterated_set = Some(obj);
+
+            let item = match item_kind {
+                PropertyNameKind::KeyAndValue => {
+                    let result = Array::create_array_from_list([element.clone(), element], context);
+                    Ok(create_iter_result_object(result.into(), false, context))
+                }
+                _ => Ok(create_iter_result_object(element, false, context)),
+            };
+            return item;
         }
 
         Ok(create_iter_result_object(
diff --git a/core/engine/src/builtins/string/string_iterator.rs b/core/engine/src/builtins/string/string_iterator.rs
index bf15695adfa..7b8d7d540d2 100644
--- a/core/engine/src/builtins/string/string_iterator.rs
+++ b/core/engine/src/builtins/string/string_iterator.rs
@@ -69,35 +69,49 @@ impl StringIterator {
 
     /// `StringIterator.prototype.next( )`
     pub(crate) fn next(this: &JsValue, _: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
-        let object = this.as_object();
-        let mut string_iterator = object
-            .as_ref()
-            .and_then(JsObject::downcast_mut::<Self>)
-            .ok_or_else(|| JsNativeError::typ().with_message("`this` is not an ArrayIterator"))?;
+        let object = this
+            .as_object()
+            .filter(|o| o.is::<Self>())
+            .ok_or_else(|| JsNativeError::typ().with_message("`this` is not a StringIterator"))?;
 
-        if string_iterator.string.is_empty() {
+        let (mut string, position) = {
+            let string_iterator = object
+                .downcast_ref::<Self>()
+                .expect("already checked that it is a StringIterator");
+            (string_iterator.string.clone(), string_iterator.next_index)
+        };
+
+        if string.is_empty() {
             return Ok(create_iter_result_object(
                 JsValue::undefined(),
                 true,
                 context,
             ));
         }
-        let native_string = &string_iterator.string;
-        let len = native_string.len();
-        let position = string_iterator.next_index;
+        let len = string.len();
         if position >= len {
-            string_iterator.string = js_string!();
+            object
+                .downcast_mut::<Self>()
+                .expect("already checked")
+                .string = js_string!();
             return Ok(create_iter_result_object(
                 JsValue::undefined(),
                 true,
                 context,
             ));
         }
-        let code_point = native_string.code_point_at(position);
-        string_iterator.next_index += code_point.code_unit_count();
+
+        let code_point = string.code_point_at(position);
+        let next_index = position + code_point.code_unit_count();
+
+        object
+            .downcast_mut::<Self>()
+            .expect("already checked")
+            .next_index = next_index;
+
         let result_string = crate::builtins::string::String::substring(
-            &string_iterator.string.clone().into(),
-            &[position.into(), string_iterator.next_index.into()],
+            &string.into(),
+            &[position.into(), next_index.into()],
             context,
         )?;
         Ok(create_iter_result_object(result_string, false, context))

From 843e41fe9f99ea9042b0cd5b7f867cc5d9cacda7 Mon Sep 17 00:00:00 2001
From: shruti2522 <shruti.apc01@gmail.com>
Date: Sun, 23 Aug 2026 15:46:04 +0000
Subject: [PATCH 19/19] fix: UAF in ForInIterator::next and AsyncGeneratorYield
 opcode

ForInIterator::next was holding a RefMut borrow across multiple
context-triggering calls (__own_property_keys__, __get_own_property__,
create_iter_result_object). Restructured to narrow borrow scope.

AsyncGeneratorYield opcode was holding a borrow_mut guard while calling
err.into_opaque(context) inside the Throw branch. Replaced with a
scoped borrow that clones the queue front before dropping the guard.
---
 .../src/builtins/object/for_in_iterator.rs    | 67 ++++++++++++++-----
 .../src/vm/opcode/generator/yield_stm.rs      | 24 ++++---
 2 files changed, 62 insertions(+), 29 deletions(-)

diff --git a/core/engine/src/builtins/object/for_in_iterator.rs b/core/engine/src/builtins/object/for_in_iterator.rs
index dfeac3601e1..03fec1e6fee 100644
--- a/core/engine/src/builtins/object/for_in_iterator.rs
+++ b/core/engine/src/builtins/object/for_in_iterator.rs
@@ -86,16 +86,28 @@ impl ForInIterator {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-%foriniteratorprototype%.next
     pub(crate) fn next(this: &JsValue, _: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
-        let object = this.as_object();
-        let mut iterator = object
-            .as_ref()
-            .and_then(|o| o.downcast_mut::<Self>())
+        let object = this
+            .as_object()
+            .filter(|o| o.is::<Self>())
             .ok_or_else(|| JsNativeError::typ().with_message("`this` is not a ForInIterator"))?;
-        let mut object = iterator.object.to_object(context)?;
+
+        let mut current_object = {
+            let iterator = object.downcast_ref::<Self>().expect("already checked");
+            iterator.object.clone()
+        };
+
+        let mut current_object_obj = current_object.to_object(context)?;
         loop {
-            if !iterator.object_was_visited {
-                let keys = object
+            let was_visited = {
+                let iterator = object.downcast_ref::<Self>().expect("checked");
+                iterator.object_was_visited
+            };
+
+            if !was_visited {
+                let keys = current_object_obj
                     .__own_property_keys__(&mut InternalMethodPropertyContext::new(context))?;
+
+                let mut iterator = object.downcast_mut::<Self>().expect("checked");
                 for k in keys {
                     match k {
                         PropertyKey::String(ref k) => {
@@ -109,23 +121,40 @@ impl ForInIterator {
                 }
                 iterator.object_was_visited = true;
             }
-            while let Some(r) = iterator.remaining_keys.pop_front() {
-                if !iterator.visited_keys.contains(&r)
-                    && let Some(desc) = object.__get_own_property__(
+
+            loop {
+                let r = {
+                    let mut iterator = object.downcast_mut::<Self>().expect("checked");
+                    iterator.remaining_keys.pop_front()
+                };
+
+                let Some(r) = r else { break };
+
+                let already_visited = {
+                    let iterator = object.downcast_ref::<Self>().expect("checked");
+                    iterator.visited_keys.contains(&r)
+                };
+
+                if !already_visited {
+                    let desc = current_object_obj.__get_own_property__(
                         &PropertyKey::from(r.clone()),
                         &mut InternalMethodPropertyContext::new(context),
-                    )?
-                {
-                    iterator.visited_keys.insert(r.clone());
-                    if desc.expect_enumerable() {
-                        return Ok(create_iter_result_object(JsValue::new(r), false, context));
+                    )?;
+
+                    if let Some(desc) = desc {
+                        let mut iterator = object.downcast_mut::<Self>().expect("checked");
+                        iterator.visited_keys.insert(r.clone());
+                        if desc.expect_enumerable() {
+                            return Ok(create_iter_result_object(JsValue::new(r), false, context));
+                        }
                     }
                 }
             }
-            let proto = object.prototype().clone();
+
+            let proto = current_object_obj.prototype().clone();
             match proto {
                 Some(o) => {
-                    object = o;
+                    current_object_obj = o;
                 }
                 _ => {
                     return Ok(create_iter_result_object(
@@ -135,7 +164,9 @@ impl ForInIterator {
                     ));
                 }
             }
-            iterator.object = JsValue::new(object.clone());
+
+            let mut iterator = object.downcast_mut::<Self>().expect("checked");
+            iterator.object = JsValue::new(current_object_obj.clone());
             iterator.object_was_visited = false;
         }
     }
diff --git a/core/engine/src/vm/opcode/generator/yield_stm.rs b/core/engine/src/vm/opcode/generator/yield_stm.rs
index bcf281412e7..44d21aa1a91 100644
--- a/core/engine/src/vm/opcode/generator/yield_stm.rs
+++ b/core/engine/src/vm/opcode/generator/yield_stm.rs
@@ -81,15 +81,18 @@ impl AsyncGeneratorYield {
             return context.handle_error(err);
         }
 
-        let mut r#gen = async_generator_object.borrow_mut();
-
-        // 10. Let queue be generator.[[AsyncGeneratorQueue]].
-        // 11. If queue is not empty, then
-        //     a. NOTE: Execution continues without suspending the generator.
-        //     b. Let toYield be the first element of queue.
-        if let Some(next) = r#gen.data().queue.front() {
-            // c. Let resumptionValue be Completion(toYield.[[Completion]]).
-            let resume_kind = match next.completion.clone() {
+        // 10. Let queue be generator.[[AsyncGeneratorQueue]]
+        // 11. If queue is not empty, resume without suspending.
+        let next_completion = async_generator_object
+            .borrow()
+            .data()
+            .queue
+            .front()
+            .map(|n| n.completion.clone());
+
+        if let Some(next) = next_completion {
+            // c. Let resumptionValue be Completion(toYield.[[Completion]])
+            let resume_kind = match next {
                 CompletionRecord::Normal(val) => {
                     context.vm.stack.push(val);
                     GeneratorResumeKind::Normal
@@ -115,9 +118,8 @@ impl AsyncGeneratorYield {
         }
 
         // 12. Else,
-
         //     a. Set generator.[[AsyncGeneratorState]] to suspended-yield.
-        r#gen.data_mut().state = AsyncGeneratorState::SuspendedYield;
+        async_generator_object.borrow_mut().data_mut().state = AsyncGeneratorState::SuspendedYield;
 
         //     TODO: b. Remove genContext from the execution context stack and restore the execution context that is at the top of the execution context stack as the running execution context.
         //     TODO: c. Let callerContext be the running execution context.