Paramspec cannot be used as tuple/dict

[kasium]

Bug Report

I face issues, when using ParamSpec.args as a tuple and ParamSpec.kwargs as a dict

To Reproduce

Execute mypy on the following code

from typing_extensions import ParamSpec
from typing import Callable

P = ParamSpec("P")

def foo(func: Callable[P, None]):
    def _inner(*args: P.args, **kwargs: P.kwargs):
        x = kwargs.pop("x")

Expected Behavior

It works

Actual Behavior

Error: test.py:8:13: error: "P.kwargs" has no attribute "pop" [attr-defined]

Your Environment

• Mypy version used: 0.941
• Mypy command-line flags: none
• Mypy configuration options from mypy.ini (and other config files): none
• Python version used: 3.7.1
• Operating system and version: Linux

[AlexWaygood]

I just closed #12660 as a duplicate. Here's the repro from that issue, by @rbroderi:

from typing import TypeVar, Callable, ParamSpec
from functools import wraps

P = ParamSpec("P")
R = TypeVar("R")

def dec_test(func: Callable[P, R]) -> Callable[P, R]:
    @wraps(func)
    def inner(*args: P.args, **kwargs: P.kwargs) -> R:
        for a in args:  # error: "P.args" has no attribute "__iter__" (not iterable)
            print(a)
        for arg_k, arg_v in kwargs.items():  # error: "P.kwargs" has no attribute "items"
            print(f"{arg_k},{arg_v}")
        return func(*args, **kwargs)
  
    return inner

Playground link: https://mypy-play.net/?mypy=latest&python=3.10&gist=52d9dbf3999e25e8a72c3bb20c1cb097

[svenpanne]

I don't think that this is fully fixed, a slight variation using destructuring doesn't work:

from collections.abc import Callable
from typing import ParamSpec

P = ParamSpec("P")

def foo(func: Callable[P, None]) -> None:
    def _inner(*args: P.args, **kwargs: P.kwargs) -> None:
        x, *y = args

See https://mypy-play.net/?mypy=latest&python=3.10&gist=0c605f87eb31c12b25c7da8f7c2819cd. You get the error: main.py:8: error: "P.args" object is not iterable. The really funny thing is that looping with for x in args works. Can you re-open this ticket?

[AlexWaygood]

@svenpanne, I fixed that just the other day in #13459. It'll be included in the next mypy release (0.980).