Callable[[T|None],TypeGuard[T]] is incompatible with Callable[[int|None],TypeGuard[int]]?

[felebsp]

I have trouble understanding why mypy complains about Callable[[T|None],TypeGuard[T]] being incompatible with Callable[[int|None],TypeGuard[int]] when T is a TypeVar in this context. (The error happens in the last line)

import typing as t
from random import random

T = t.TypeVar('T')
def take_while(
    f: t.Callable[[t.Optional[T]], t.TypeGuard[T]], it: t.Iterator[t.Optional[T]]
) -> t.Iterable[T]:
    for x in it:
        if f(x):
            yield x
        else:
            return

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

def get_iterator() -> t.Iterable[t.Optional[int]]:
    while True:
        if random() > 0.2:
            yield int(random() * 100)
        else:
            yield None

take_while(is_not_none, iter(get_iterator()))

Here's the code in the mypy playground https://mypy-play.net/?mypy=latest&python=3.11&gist=59ff502958f7588377cdba0efd3044db

I'd be thankfull if someone helped me understand mypy's reasoning

[erictraut]

This type checks without error in pyright. I recommend filing a bug in the mypy issue tracker.