From 5982bb01b3adc6f9015b50abd96f5c58009dfc9a Mon Sep 17 00:00:00 2001
From: ahogappa <ahogappa@gmail.com>
Date: Tue, 11 Aug 2026 08:14:58 +0900
Subject: [PATCH 1/2] Fix crash on anonymous splat in find pattern (`[*, x,
 *]`)

Prism represents an anonymous splat as a `SplatNode` whose `expression`
is nil, so `FindPatternNode#initialize` passed nil into
`AST.create_pattern_node` and crashed with:

    undefined method 'type' for nil (NoMethodError)
    lib/typeprof/core/ast.rb:334:in 'AST.create_pattern_node'
    lib/typeprof/core/ast/pattern.rb:61:in 'FindPatternNode#initialize'

`left` and `right` are never nil (the grammar requires both splats), so
check `expression` instead, as `ArrayPatternNode` already does for its
rest pattern.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
---
 lib/typeprof/core/ast/pattern.rb | 4 ++--
 scenario/patterns/find_pat.rb    | 8 +++++++-
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/lib/typeprof/core/ast/pattern.rb b/lib/typeprof/core/ast/pattern.rb
index d418a3611..ae38f5c08 100644
--- a/lib/typeprof/core/ast/pattern.rb
+++ b/lib/typeprof/core/ast/pattern.rb
@@ -58,9 +58,9 @@ def install0(genv)
     class FindPatternNode < Node
       def initialize(raw_node, lenv)
         super(raw_node, lenv)
-        @left = raw_node.left ? AST.create_pattern_node(raw_node.left.expression, lenv) : nil
+        @left = raw_node.left.expression ? AST.create_pattern_node(raw_node.left.expression, lenv) : nil
         @requireds = raw_node.requireds.map {|raw_elem| AST.create_pattern_node(raw_elem, lenv) }
-        @right = raw_node.right ? AST.create_pattern_node(raw_node.right.expression, lenv) : nil
+        @right = raw_node.right.expression ? AST.create_pattern_node(raw_node.right.expression, lenv) : nil
       end
 
       attr_reader :left, :requireds, :right
diff --git a/scenario/patterns/find_pat.rb b/scenario/patterns/find_pat.rb
index 57834385d..74e7bf0ae 100644
--- a/scenario/patterns/find_pat.rb
+++ b/scenario/patterns/find_pat.rb
@@ -5,6 +5,12 @@ def check(x)
     :foo
   in *a, String, *b
     :bar # TODO: this should be excluded
+  in [*, Integer, *b]
+    :anon_left
+  in [*a, Integer, *]
+    :anon_right
+  in [*, Integer, *]
+    :anon_both
   else
     :zzz
   end
@@ -14,5 +20,5 @@ def check(x)
 
 ## assert
 class Object
-  def check: (Array[Integer]) -> (:bar | :foo | :zzz)
+  def check: (Array[Integer]) -> (:anon_both | :anon_left | :anon_right | :bar | :foo | :zzz)
 end

From 2aa3eddf7a679419b27c064f3106754a8191dca4 Mon Sep 17 00:00:00 2001
From: ahogappa <ahogappa@gmail.com>
Date: Tue, 11 Aug 2026 08:15:32 +0900
Subject: [PATCH 2/2] Fix crash on `{**nil}` pattern

`HashPatternNode#rest` is `AssocSplatNode | NoKeywordsParameterNode |
nil`, but the code assumed it always responds to `value`, so `in {**nil}`
crashed with:

    undefined method 'value' for an instance of Prism::NoKeywordsParameterNode
    lib/typeprof/core/ast/pattern.rb:42:in 'HashPatternNode#initialize'

Dispatch on the node class, mirroring `ArrayPatternNode#initialize`.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
---
 lib/typeprof/core/ast/pattern.rb | 9 ++++++++-
 scenario/patterns/hash_pat.rb    | 4 +++-
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/lib/typeprof/core/ast/pattern.rb b/lib/typeprof/core/ast/pattern.rb
index ae38f5c08..f41e91b2a 100644
--- a/lib/typeprof/core/ast/pattern.rb
+++ b/lib/typeprof/core/ast/pattern.rb
@@ -39,7 +39,14 @@ def initialize(raw_node, lenv)
         @keys = raw_node.elements.map {|raw_assoc| raw_assoc.key.value.to_sym }
         @values = raw_node.elements.map {|raw_assoc| AST.create_pattern_node(raw_assoc.value, lenv) }
         @rest = !!raw_node.rest
-        @rest_pattern = raw_node.rest && raw_node.rest.value ? AST.create_pattern_node(raw_node.rest.value, lenv) : nil
+        @rest_pattern = case raw_node.rest
+                        when Prism::AssocSplatNode
+                          AST.create_pattern_node(raw_node.rest.value, lenv) if raw_node.rest.value
+                        when Prism::NoKeywordsParameterNode, nil
+                          nil
+                        else
+                          raise
+                        end
       end
 
       attr_reader :keys, :values, :rest, :rest_pattern
diff --git a/scenario/patterns/hash_pat.rb b/scenario/patterns/hash_pat.rb
index 70e8c494f..d5d65cc23 100644
--- a/scenario/patterns/hash_pat.rb
+++ b/scenario/patterns/hash_pat.rb
@@ -12,6 +12,8 @@ def check(x)
     :baz
   in MyHash[a: Integer]
     :qux
+  in { **nil }
+    :no_kw
   else
     :zzz
   end
@@ -23,5 +25,5 @@ def check(x)
 class MyHash
 end
 class Object
-  def check: ({ a: Integer }) -> (:bar | :baz | :foo | :qux | :zzz)
+  def check: ({ a: Integer }) -> (:bar | :baz | :foo | :no_kw | :qux | :zzz)
 end