`zip()` doesn't work

[grievejia]

Minimal repro:

def foo(x: list[int], y: list[str]) -> None:
    for p in zip(x, y):
        reveal_type(p)

Expected: some form of tuple[int, str]
Actual: Unknown

[ndmitchell]

from typing import *

class zipppy[T]:
    def __new__(cls) -> zipppy[bool]: ...

reveal_type(zipppy())

This reveals the type to be zippy[Any] which is wrong.