Fixed generic aliases not passing checks against type (#433)

Co-authored-by: Alex Grönholm <alex.gronholm@nextday.fi>

docs/versionhistory.rst

@@ -11,6 +11,9 @@ This library adheres to
   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>`_)
+- Fixed ``typing`` types (``dict[str, int]``, ``List[str]``, etc.) not passing checks
+  against ``type`` or ``Type``
+  (`#432 <https://github.com/agronholm/typeguard/issues/432>`_, PR by Yongxin Wang)
 
 **4.1.5** (2023-09-11)
 

src/typeguard/_checkers.py

@@ -83,6 +83,9 @@
 ]
 
 checker_lookup_functions: list[TypeCheckLookupCallback] = []
+generic_alias_types: tuple[type, ...] = (type(List), type(List[Any]))
+if sys.version_info >= (3, 9):
+    generic_alias_types += (types.GenericAlias,)
 
 
 # Sentinel
@@ -440,7 +443,7 @@ def check_class(
     args: tuple[Any, ...],
     memo: TypeCheckMemo,
 ) -> None:
-    if not isclass(value):
+    if not isclass(value) and not isinstance(value, generic_alias_types):
         raise TypeCheckError("is not a class")
 
     if not args:
@@ -475,7 +478,7 @@ def check_class(
             raise TypeCheckError(
                 f"did not match any element in the union:\n{formatted_errors}"
             )
-    elif not issubclass(value, expected_class):
+    elif not issubclass(value, expected_class):  # type: ignore[arg-type]
         raise TypeCheckError(f"is not a subclass of {qualified_name(expected_class)}")
 
 

tests/test_checkers.py

@@ -891,6 +891,14 @@ def test_union_typevar(self):
         T = TypeVar("T", bound=Parent)
         check_type(Child, Type[T])
 
+    @pytest.mark.parametrize("check_against", [type, Type[Any]])
+    def test_generic_aliase(self, check_against):
+        if sys.version_info >= (3, 9):
+            check_type(dict[str, str], check_against)
+
+        check_type(Dict, check_against)
+        check_type(Dict[str, str], check_against)
+
 
 class TestIO:
     @pytest.mark.parametrize(