Parametrised Callable allowed only when used as type alias

I've found a case where a Callable is not allowed when used directly, but is allowed if used as an alias

from typing import TypeVar, Callable

T = TypeVar('T')

MkFoo = Callable[[T], list[T]]

def foo(mkfoo: MkFoo) -> None:
    _ = mkfoo(0)

works, but replacing MkFoo by its definition

def foo(mkfoo: Callable[[T], list[T]]) -> None:
    _ = mkfoo(0)

produces

main.py:13: error: Argument 1 has incompatible type "int"; expected "T"

从 main.py 中展示的两个复现开始，比较直接使用的参数化 Callable 与等效的类型别名。检查由此产生的类型检查器行为和现有讨论；完成的标准是确定两种形式是否都应被接受，并为已达成共识的行为添加或更新覆盖测试。