Type not narrowed on `isinstance(obj, Callable)` check

I received this bug report from a pyright user: https://github.com/microsoft/pyright/issues/2274. Mypy exhibits the same behavior, so I'm wondering whether it's a bug or the intended behavior.

In this code sample, mypy (and pyright) do not currently narrow the type of obj based on the isinstance(obj, Callable) conditional check.

from typing import Callable, Union

def some_func(obj: Union[Callable, int]):
    if isinstance(obj, Callable):
        reveal_type(obj) # Type of "obj" is "(*args: Unknown, **kwargs: Unknown) -> Unknown | int"
    else:
        reveal_type(obj) # Type of "obj" is "(*args: Unknown, **kwargs: Unknown) -> Unknown | int"

I'm wondering if there's a reason why mypy does not perform type narrowing in this case. Is there a type safety reason? Is callable() the preferred way to check for callables?

I've searched the issue database, and it doesn't appear to be an issue that anyone has previously reported.

Commencez par exécuter le reproducteur Python avec mypy et vérifier les types révélés pour les deux branches. Suivez le comportement de narrowing existant de isinstance et Callable, y compris les tests ou la documentation associés. Le travail est considéré comme terminé lorsqu’il est établi si ce comportement est intentionnel et, s’il s’agit d’un bug, qu’un résultat de narrowing testé est défini.