from typing import Any, Callable, Protocol, runtime_checkable

class Proto(Protocol):
    def foo(self, x: int, /) -> object: ...

def test_object(x: object) -> None:
    match x:
        case Proto() as y:  # No Error
            reveal_type(y)  # N: Revealed type is "__main__.Proto"

    if isinstance(x, Proto):  # E: Only @runtime_checkable protocols ...
        reveal_type(x)  # N: Revealed type is "__main__.Proto"