[functools] Use ParamSpec for single dispatch

Author: srittau

stdlib/functools.pyi

@@ -26,6 +26,7 @@ __all__ = [
 _T = TypeVar("_T")
 _T_co = TypeVar("_T_co", covariant=True)
 _S = TypeVar("_S")
+_P = ParamSpec("_P")
 _PWrapped = ParamSpec("_PWrapped")
 _RWrapped = TypeVar("_RWrapped")
 _PWrapper = ParamSpec("_PWrapper")
@@ -195,38 +196,38 @@ else:
     _RegType: TypeAlias = type[Any]
 
 @type_check_only
-class _SingleDispatchCallable(Generic[_T]):
-    registry: types.MappingProxyType[Any, Callable[..., _T]]
-    def dispatch(self, cls: Any) -> Callable[..., _T]: ...
+class _SingleDispatchCallable(Generic[_P, _T]):
+    registry: types.MappingProxyType[Any, Callable[_P, _T]]
+    def dispatch(self, cls: Any) -> Callable[_P, _T]: ...
     # @fun.register(complex)
     # def _(arg, verbose=False): ...
     @overload
-    def register(self, cls: _RegType, func: None = None) -> Callable[[Callable[..., _T]], Callable[..., _T]]: ...
+    def register(self, cls: _RegType, func: None = None) -> Callable[[Callable[_P, _T]], Callable[_P, _T]]: ...
     # @fun.register
     # def _(arg: int, verbose=False):
     @overload
-    def register(self, cls: Callable[..., _T], func: None = None) -> Callable[..., _T]: ...
+    def register(self, cls: Callable[_P, _T], func: None = None) -> Callable[_P, _T]: ...
     # fun.register(int, lambda x: x)
     @overload
-    def register(self, cls: _RegType, func: Callable[..., _T]) -> Callable[..., _T]: ...
+    def register(self, cls: _RegType, func: Callable[_P, _T]) -> Callable[_P, _T]: ...
     def _clear_cache(self) -> None: ...
-    def __call__(self, /, *args: Any, **kwargs: Any) -> _T: ...
+    def __call__(self, /, *args: _P.args, **kwargs: _P.kwargs) -> _T: ...
 
-def singledispatch(func: Callable[..., _T]) -> _SingleDispatchCallable[_T]: ...
+def singledispatch(func: Callable[_P, _T]) -> _SingleDispatchCallable[_P, _T]: ...
 
-class singledispatchmethod(Generic[_T]):
-    dispatcher: _SingleDispatchCallable[_T]
-    func: Callable[..., _T]
-    def __init__(self, func: Callable[..., _T]) -> None: ...
+class singledispatchmethod(Generic[_P, _T]):
+    dispatcher: _SingleDispatchCallable[_P, _T]
+    func: Callable[_P, _T]
+    def __init__(self, func: Callable[_P, _T]) -> None: ...
     @property
     def __isabstractmethod__(self) -> bool: ...
     @overload
-    def register(self, cls: _RegType, method: None = None) -> Callable[[Callable[..., _T]], Callable[..., _T]]: ...
+    def register(self, cls: _RegType, method: None = None) -> Callable[[Callable[_P, _T]], Callable[_P, _T]]: ...
     @overload
-    def register(self, cls: Callable[..., _T], method: None = None) -> Callable[..., _T]: ...
+    def register(self, cls: Callable[_P, _T], method: None = None) -> Callable[_P, _T]: ...
     @overload
-    def register(self, cls: _RegType, method: Callable[..., _T]) -> Callable[..., _T]: ...
-    def __get__(self, obj: _S, cls: type[_S] | None = None) -> Callable[..., _T]: ...
+    def register(self, cls: _RegType, method: Callable[_P, _T]) -> Callable[_P, _T]: ...
+    def __get__(self, obj: _S, cls: type[_S] | None = None) -> Callable[_P, _T]: ...
 
 class cached_property(Generic[_T_co]):
     func: Callable[[Any], _T_co]