inspect, asyncio: Use more TypeGuards (#8057)

stdlib/asyncio/coroutines.pyi

@@ -1,21 +1,28 @@
 import sys
-from collections.abc import Coroutine
-from typing import Any
-from typing_extensions import TypeGuard
+from collections.abc import Awaitable, Callable, Coroutine
+from typing import Any, TypeVar, overload
+from typing_extensions import ParamSpec, TypeGuard
 
 if sys.version_info >= (3, 11):
     __all__ = ("iscoroutinefunction", "iscoroutine")
 else:
     __all__ = ("coroutine", "iscoroutinefunction", "iscoroutine")
 
+_T = TypeVar("_T")
+_FunctionT = TypeVar("_FunctionT", bound=Callable[..., Any])
+_P = ParamSpec("_P")
+
 if sys.version_info < (3, 11):
-    from collections.abc import Callable
-    from typing import TypeVar
+    def coroutine(func: _FunctionT) -> _FunctionT: ...
 
-    _F = TypeVar("_F", bound=Callable[..., Any])
-    def coroutine(func: _F) -> _F: ...
-
-def iscoroutinefunction(func: object) -> bool: ...
+@overload
+def iscoroutinefunction(func: Callable[..., Coroutine[Any, Any, Any]]) -> bool: ...
+@overload
+def iscoroutinefunction(func: Callable[_P, Awaitable[_T]]) -> TypeGuard[Callable[_P, Coroutine[Any, Any, _T]]]: ...
+@overload
+def iscoroutinefunction(func: Callable[_P, object]) -> TypeGuard[Callable[_P, Coroutine[Any, Any, Any]]]: ...
+@overload
+def iscoroutinefunction(func: object) -> TypeGuard[Callable[..., Coroutine[Any, Any, Any]]]: ...
 
 # Can actually be a generator-style coroutine on Python 3.7
 def iscoroutine(obj: object) -> TypeGuard[Coroutine[Any, Any, Any]]: ...