Fixed TypedDict from typing_extensions not being recognized as one

Fixes #443.

docs/versionhistory.rst

@@ -9,6 +9,8 @@ This library adheres to
 - Avoid creating reference cycles when type checking unions
 - Fixed ``Optional[...]`` being removed from the AST if it was located within a
   subscript (`#442 <https://github.com/agronholm/typeguard/issues/442>`_)
+- Fixed ``TypedDict`` from ``typing_extensions`` not being recognized as one
+  (`#443 <https://github.com/agronholm/typeguard/issues/443>`_)
 
 **4.1.5** (2023-09-11)
 

src/typeguard/_checkers.py

@@ -43,14 +43,18 @@
 from ._memo import TypeCheckMemo
 from ._utils import evaluate_forwardref, get_stacklevel, get_type_name, qualified_name
 
+if sys.version_info >= (3, 13):
+    from typing import is_typeddict
+else:
+    from typing_extensions import is_typeddict
+
 if sys.version_info >= (3, 11):
     from typing import (
         Annotated,
         TypeAlias,
         get_args,
         get_origin,
         get_type_hints,
-        is_typeddict,
     )
 
     SubclassableAny = Any
@@ -61,7 +65,6 @@
         get_args,
         get_origin,
         get_type_hints,
-        is_typeddict,
     )
     from typing_extensions import Any as SubclassableAny
 

tests/conftest.py

@@ -2,9 +2,11 @@
 import re
 import string
 import sys
+import typing
 from itertools import count
 
 import pytest
+import typing_extensions
 
 version_re = re.compile(r"_py(\d)(\d)\.py$")
 
@@ -25,3 +27,13 @@ def sample_set() -> set:
         dummy_set = {letter, num}
         if next(iter(dummy_set)) == letter:
             return dummy_set
+
+
+@pytest.fixture(
+    params=[
+        pytest.param(typing, id="typing"),
+        pytest.param(typing_extensions, id="typing_extensions"),
+    ]
+)
+def typing_provider(request):
+    return request.param

tests/test_checkers.py

@@ -27,7 +27,6 @@
     TextIO,
     Tuple,
     Type,
-    TypedDict,
     TypeVar,
     Union,
 )
@@ -473,8 +472,10 @@ class TestTypedDict:
             ),
         ],
     )
-    def test_typed_dict(self, value, total: bool, error_re: Optional[str]):
-        class DummyDict(TypedDict, total=total):
+    def test_typed_dict(
+        self, value, total: bool, error_re: Optional[str], typing_provider
+    ):
+        class DummyDict(typing_provider.TypedDict, total=total):
             x: int
             y: str
 
@@ -483,8 +484,8 @@ class DummyDict(TypedDict, total=total):
         else:
             check_type(value, DummyDict)
 
-    def test_inconsistent_keys_invalid(self):
-        class DummyDict(TypedDict):
+    def test_inconsistent_keys_invalid(self, typing_provider):
+        class DummyDict(typing_provider.TypedDict):
             x: int
 
         pytest.raises(