Incorrect narrowing for class pattern when `Callable` is used

[randolf-scholz]

Possibly even bug, maybe related to #6600 ?

from collections.abc import Callable
from typing import TypeVar

T = TypeVar("T")


def foo(obj: T | Callable[..., T]) -> None:
    match obj:
        case Callable() as func:
            func()

I guess the issue is that if T is callable, then its signature might be incompatible? But for completely unknown T, I'd assume that func should be inferred as the widest possible type Callable[..., Any].

[erictraut]

Yes, this is a bug. The current type narrowing logic for class pattern matching doesn't properly handle Callable.

[erictraut]

This will be fixed in the next release.

[erictraut]

This is addressed in pyright 1.1.339, which I just published. It will also be included in a future release of pylance.