[functools] Allow method override with @cache decorator (#15238)

Author: emmanuel-ferdman

stdlib/@tests/test_cases/check_functools.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from functools import cached_property, wraps
+from functools import cache, cached_property, wraps
 from typing import Callable, TypeVar
 from typing_extensions import ParamSpec, assert_type
 
@@ -96,3 +96,15 @@ class Y(X):
     @cached_property
     def some(self) -> Child:  # safe override
         return Child()
+
+
+class CachedParent:
+    @cache
+    def method(self) -> Parent:
+        return Parent()
+
+
+class CachedChild(CachedParent):
+    @cache
+    def method(self) -> Child:
+        return Child()

stdlib/functools.pyi

@@ -54,14 +54,14 @@ class _CacheParameters(TypedDict):
     typed: bool
 
 @final
-class _lru_cache_wrapper(Generic[_T]):
-    __wrapped__: Callable[..., _T]
-    def __call__(self, *args: Hashable, **kwargs: Hashable) -> _T: ...
+class _lru_cache_wrapper(Generic[_T_co]):
+    __wrapped__: Callable[..., _T_co]
+    def __call__(self, *args: Hashable, **kwargs: Hashable) -> _T_co: ...
     def cache_info(self) -> _CacheInfo: ...
     def cache_clear(self) -> None: ...
     def cache_parameters(self) -> _CacheParameters: ...
-    def __copy__(self) -> _lru_cache_wrapper[_T]: ...
-    def __deepcopy__(self, memo: Any, /) -> _lru_cache_wrapper[_T]: ...
+    def __copy__(self) -> _lru_cache_wrapper[_T_co]: ...
+    def __deepcopy__(self, memo: Any, /) -> _lru_cache_wrapper[_T_co]: ...
 
 @overload
 def lru_cache(maxsize: int | None = 128, typed: bool = False) -> Callable[[Callable[..., _T]], _lru_cache_wrapper[_T]]: ...