[FR] Make Never raisable

[Azureblade3808]

Currently, a variable with type Never is not allowed to be raised.

e = None
...
if e is not None:
    raise e  # reportGeneralTypeIssues: "Never" does not derive from BaseException

But technically said, Never is indeed a subtype of BaseException, so I don't think the reason is very convincing.

If such usages are allowed, it will be easier to implement tests for unraisable exceptions. For my case, it is something like --

import sys
import pytest

def foo() -> None:
    """
    This function may either raise normally or cause an unraisable exception.
    """
    ...

def test() -> None:
    def unraisablehook(args: sys.UnraisableHookArgs, /) -> None:
        nonlocal e
        e = args.exc_value

    old_unraisablehook = sys.unraisablehook
    sys.unraisablehook = unraisablehook

    with pytest.raises(Exception):
        e = None
        foo()
        if e is not None:
            raise e

    sys.unraisablehook = old_unraisablehook

[erictraut]

This will be addressed in the next release.