False positive bad-argument-type when calling a method with AnyStr

[superbobry]

Describe the Bug

Reproducer:

from typing import AnyStr

class A:
  @classmethod
  def create(cls, x: AnyStr | None): ...


def test(x: AnyStr | None):
  A.create(x)

Output:

ERROR Argument `AnyStr | None` is not assignable to parameter `x` with type `str | None` in function `A.create` [bad-argument-type]
  --> /tmp/foo.py:10:12
   |
10 |   A.create(x)

It looks like AnyStr is specialized to str? Possibly a duplicate of #2370.

Sandbox Link

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(Only applicable for extension issues) IDE Information

No response

[migeed-z]

This appears to be related to #105? it looks like we are pinning the typevar that has type AnyStr to str. So to fundamentally solve this, I think issue 105 would have to be solved first. So this is blocked by the pinning issue. cc @rchen152 in case there is an alternative thought.

[rchen152]

@migeed-z Might worth checking what type we're passing in to create in the A.create(x) call - it's possible that we're not handling AnyStr correctly there. But if we are, then yeah, the str | None in the error message suggests that we're probably pinning AnyStr to the wrong type.