From fc94c81173a50ad24476626d8aacf1148794894e Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Wed, 7 Oct 2026 15:48:27 +0100
Subject: [PATCH] [mypyc] Fix crash when exception variable is captured by
 nested function

Fixes mypyc/mypyc#1184.

This crashed with "unexpected type DeletedType":

```python
def f() -> None:
    try:
        raise RuntimeError()
    except RuntimeError as exc:
        fn = lambda: print(exc)
```

Mypy gives the variable of an except clause the type `DeletedType`
after the except block, and this type is used when adding a captured
variable to the environment class of the function. Now we map
`DeletedType` to `object`.
---
 mypyc/irbuild/mapper.py             |  4 ++++
 mypyc/test-data/run-exceptions.test | 29 +++++++++++++++++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/mypyc/irbuild/mapper.py b/mypyc/irbuild/mapper.py
index 523c718c9b867..ac472117c08cb 100644
--- a/mypyc/irbuild/mapper.py
+++ b/mypyc/irbuild/mapper.py
@@ -6,6 +6,7 @@
 from mypy.types import (
     AnyType,
     CallableType,
+    DeletedType,
     Instance,
     LiteralType,
     NoneTyp,
@@ -166,6 +167,9 @@ def type_to_rtype(self, typ: Type | None) -> RType:
         elif isinstance(typ, (UninhabitedType, UnboundType)):
             # Sure, whatever!
             return object_rprimitive
+        elif isinstance(typ, DeletedType):
+            # The type of an exception variable after the except block, for example
+            return object_rprimitive
 
         # I think we've covered everything that is supposed to
         # actually show up, so anything else is a bug somewhere.
diff --git a/mypyc/test-data/run-exceptions.test b/mypyc/test-data/run-exceptions.test
index 8257bfd9b8943..e6178876aae8b 100644
--- a/mypyc/test-data/run-exceptions.test
+++ b/mypyc/test-data/run-exceptions.test
@@ -665,3 +665,32 @@ from typing import Any
 class OtherException(Exception):
     def __new__(cls) -> Any:
         return ValueError("other")
+
+[case testExceptionVariableCapturedByNestedFunction]
+from typing import Callable, Iterator
+
+def call(f: Callable[[], str]) -> str:
+    return f()
+
+def test_lambda() -> None:
+    try:
+        raise RuntimeError("x")
+    except RuntimeError as exc:
+        assert call(lambda: str(exc)) == "x"
+
+def test_nested_function() -> None:
+    try:
+        raise ValueError("y")
+    except Exception as exc:
+        def f() -> str:
+            return type(exc).__name__ + str(exc)
+        assert call(f) == "ValueErrory"
+
+def gen() -> Iterator[str]:
+    try:
+        raise KeyError("z")
+    except KeyError as exc:
+        yield call(lambda: repr(exc))
+
+def test_generator() -> None:
+    assert list(gen()) == ["KeyError('z')"]