inspect, asyncio: Use more TypeGuards (#8057)

test_cases/stdlib/asyncio/test_coroutines.py

@@ -0,0 +1,24 @@
+from asyncio import iscoroutinefunction
+from collections.abc import Awaitable, Callable, Coroutine
+from typing import Any, Union
+from typing_extensions import assert_type
+
+
+def test_iscoroutinefunction(
+    x: Callable[[str, int], Coroutine[str, int, bytes]],
+    y: Callable[[str, int], Awaitable[bytes]],
+    z: Callable[[str, int], Union[str, Awaitable[bytes]]],
+    xx: object,
+) -> None:
+
+    if iscoroutinefunction(x):
+        assert_type(x, Callable[[str, int], Coroutine[str, int, bytes]])
+
+    if iscoroutinefunction(y):
+        assert_type(y, Callable[[str, int], Coroutine[Any, Any, bytes]])
+
+    if iscoroutinefunction(z):
+        assert_type(z, Callable[[str, int], Coroutine[Any, Any, Any]])
+
+    if iscoroutinefunction(xx):
+        assert_type(xx, Callable[..., Coroutine[Any, Any, Any]])