@disjoint_base + __new__(cls) -> Never leads to confusing error message #22306

I ran into this while improving type coverage in PyAV (src):

from typing import Never
from typing_extensions import disjoint_base

@disjoint_base
class Cat:
    def __new__(cls, /) -> Never:
        raise RuntimeError("cannot instantiate Cat")

main.py:5: error: Value of type variable "_TC" of "disjoint_base" cannot be "Callable[[], Never]"  [type-var]

https://mypy-play.net/?mypy=latest&python=3.14&gist=1f1d2c81fd843d4ba2d37355bf18b5dd

I don't think this should've lead to an error, let alone such a confusing one (from the perspective of an average typing user, because I can imagine that for mypy devs this error message is actually pretty helpful).