`filter` does not narrow `TypeVar` used in `TypeGuard` signature

Bug Report

Using filter with a TypeGuard, the TypeVar used in the TypeGuard signature is not properly narrowed.

To Reproduce

# tmp.py
from typing import Iterator, Optional, TypeVar

from typing_extensions import TypeGuard

T = TypeVar("T")


def is_not_none(x: Optional[T]) -> TypeGuard[T]:
    return x is not None


maybe_ints: list[Optional[int]] = [1, None, 2]
ints: Iterator[int] = filter(is_not_none, maybe_ints)

$ mypy tmp.py
tmp.py:14: error: Argument 1 to "filter" has incompatible type "Callable[[Optional[T]], TypeGuard[T]]"; expected "Callable[[Optional[int]], TypeGuard[int]]"
Found 1 error in 1 file (checked 1 source file)

Expected Behavior

I wouldn't expect any error. Since the second argument to filter is typed as list[Optional[int]], mypy should narrow the TypeVar T appropriately.

Your Environment

• Mypy version used: mypy 0.950
• Mypy command-line flags: none
• Mypy configuration options from mypy.ini (and other config files): none
• Python version used: 3.10

This may be related to https://github.com/python/mypy/issues/12682. I decided to open a new ticket instead of commenting on that issue because the repro above feels different from the one reported on that issue.

Beginne damit, den Bericht mit tmp.py und mypy 0.950 oder der aktuellen Version zu reproduzieren, wobei der Fokus auf filter mit is_not_none und dem TypeGuard TypeVar liegt. Verfolge den Type-Checking-Pfad für die Inferenz des filter-Callbacks und die TypeGuard-Eingrenzung; abgeschlossen ist die Aufgabe, wenn das Beispiel den Type-Check besteht und ints als Iterator[int] akzeptiert wird.