[v1.5 regression] Invalid context-manager use goes unchecked #5548

from typing import Any, Generic, TypeVar

T = TypeVar("T")

class Envoy(Generic[T]):
    def __call__(self, *args: list[Any]) -> Any:
        return None

    def __getattr__(self, key: str) -> "Envoy[T] | T | Any":
        raise AttributeError(key)

def use(e: Envoy) -> None:
    with e:  # No longer reports bad-context-manager
        pass

use(Envoy())  # Raises TypeError