Overly broad type inference when using zip(*x) to tranpose 2d iterable

Description:

When transposing a 2d iterable x: Iterable[Iterable[T]] using zip(*x), I've noticed typeshed's type annotations result in the return type being inferred as zip[tuple[Any, ...]] rather than the expected zip[tuple[T, ...]]. It would be nice if builtins.py^1 had an overload for this use case.

Expected behavior

When x has type Iterable[Iterable[T]], the expression zip(*x) should be inferred as zip[tuple[T, ...]], preserving the element type information through the transpose operation.

Actual behavior

The expression zip(*x) is inferred as zip[tuple[Any, ...]].

Possible solution

Add the following overloads to zip:

Pre 3.10:

        @overload
        def __new__(
            cls,
            *iterables: Iterable[_T1],
        ) -> zip[tuple[_T1, ...]]: ...

3.10 or later:

        @overload
        def __new__(
            cls,
            *iterables: Iterable[_T1],
            *,
            strict: bool = ...
        ) -> zip[tuple[_T1, ...]]: ...

While I have seen zip(*x) in the wild, I have not seen zip(a,b,c,*x) in any environment before, so I don't think it's necessary to write an overload for that edge case.

Apri stdlib/builtins.pyi alla definizione zip collegata e confronta gli overload esistenti con le signature proposte per le versioni precedenti alla 3.10 e per la 3.10+. Conferma che zip(*x) per Iterable[Iterable[T]] venga inferito come zip[tuple[T, ...]] anziché come zip[tuple[Any, ...]], mantenendo al contempo la gestione strict.