Alias that is generic over a ParamSpec is not hashable when using a list as parameters_expression

Bug report

Bug description:

This is slightly related to #124445, but a different issue, maybe it can be solved at the same time?

Consider the following code where [T] is a parameters_expression according to PEP 612. Similar to using Callable or using Generic[P] or Protocol[P] I would expect the following code to work and receive a hashable variable:

from typing import TypeVar
from collections.abc import Callable
type X[**P] = Callable[P, int]
T = TypeVar("T")
hash(X[[T]])
# ~~~~^^^^^^^^
# TypeError: unhashable type: 'list'

Cause:

The problem is that X[[T]].__args__ == ([T],) which cannot be hashed. I think the list should either be turned into a tuple. Either a nested one as its done for Generic and Protocol or joined like for Callable[P, str][[int]].__args__.

Discussion:

I've opened a parallel topic on discuss

CPython versions tested on:

3.13.0.rc2

Operating systems tested on:

Linux

EDIT: A thought, should this be changed for whole class in general?

从 issue 中的复现用例开始，将 ParamSpec 别名的行为与引用的 Generic、Protocol 和 Callable 案例进行比较。阅读 PEP 612、issue #124445 以及链接的讨论，以确定列表参数应变为嵌套元组还是应进行合并。完成的标准是 hash(X[[T]]) 能够在没有不可哈希列表的情况下工作，同时保留预期的参数。