stdlib: Use Never instead of NoReturn

[donBarbos]

related #13891

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2025-04-28 (@srittau): Deferred until there's a final decision in python/cpython#132941.

[srittau]

I see this as a regression. Using NoReturn instead of Never for return types is clearer. There is no intent for deprecating NoReturn that I know of.

[github-actions]

According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉

[Avasam]

Edit: I responded on the related issue: #13891 (comment)

Whilst they are equivalent. There's a semantic difference. And typeshed is no stranger to using type name alias to express different semantic (Incomplete, Unused, MaybeNone, ...) I'm -1 on this.

If python/cpython#132941 is accepted to where NoReturn is considered (soft) deprecated and there's a general agreement in the Python typing community to no longer use NoReturn, then maybe.

But as it stands:

Never is not the preferred name for return types.

I can get behind the semantic of "a function that Never returns". But I'd want widespread agreement before changing in typeshed.

[srittau]

Marking as deferred, pending the outcome of the discussion (and merged PR) of python/cpython#132941.