new type inference regression on callable

[bzoracler]

Bug Report

The new type inference introduced (default in mypy 1.7) causes the following failure:

To Reproduce & Actual Behaviour

mypy-play.net

import typing_extensions as t

T = t.TypeVar("T")
deco: t.Callable[[t.Callable[..., T]], t.Callable[..., T]]

@deco  # mypy: Argument 1 has incompatible type "Callable[[T], T | int]"; expected "Callable[..., Never]" [arg-type]
def func(item: T, /) -> T | int:
    return 0

The discovery of this was with @deco as @functools.singledispatch, which has signature def singledispatch(func: Callable[..., _T]) -> _SingleDispatchCallable[_T]: ....

Expected Behavior

No issues (as with mypy 1.6.1 without --new-type-inference and 1.7 with --old-type-inference)

Your Environment

• Mypy version used: 1.6.1 with --new-type-inference, 1.7, master,
• Mypy command-line flags: None
• Mypy configuration options from mypy.ini (and other config files): None
• Python version used: 3.10, 3.11

[ilevkivskyi]

This is a duplicate of #16451 (this has a much simpler repro, but that issue is older, so closing this one).