TypeVarTuple and ParamSpec don't work together

[LeeeeT]

Bug report

The following code gives me an error:

from typing import Generic, TypeVarTuple, ParamSpec


Ts = TypeVarTuple("Ts")

P = ParamSpec("P")


class Foo(Generic[*Ts, P]):
    pass


Foo[int, str, [bytes]]

TypeError: Too many arguments for <class 'Foo'>; actual 3, expected 2

I don't see any reasons why it doesn't work with ParamSpec. I believe it should assign int, str to Ts and [bytes] to P.

Environment

• CPython versions tested on: 3.11
• Operating system and architecture: Linux x86_64

• PR: gh-99344, gh-99379, gh-99382: Fix issues in substitution of ParamSpec and TypeVarTuple #99412

• PR: [3.11] gh-99344, gh-99379, gh-99382: Fix issues in substitution of ParamSpec and TypeVarTuple (GH-99412) #99866

[JelleZijlstra]

cc @mrahtz @serhiy-storchaka

[serhiy-storchaka]

Yes, such case is just not supported in the code, and it needs a nontrivial rewriting. I have found also several other similar bugs. I am working on the solution, PRs are almost ready.

[mrahtz]

Thank you for taking care of this, Serhiy!