Runtime Access to Generic Types on Class Method

I would like to be able to access the type arguments of a class from its class methods.

To make this concrete, here is a generic instance:

import typing
import typing_inspect

T = typing.TypeVar("T")

class Inst(typing.Generic[T]):
    @classmethod
    def hi(cls):
        return cls

I can get its generic args:

>>> typing_inspect.get_args(Inst[int])
(int,)

But, these seem to get erased inside the class methods:

>>> typing_inspect.get_args(Inst[int].hi())
()

从 issue 中的 Inst[int] 和 classmethod 示例开始，然后检查运行时解析泛型别名时涉及的 typing 和 typing_inspect 行为。当类方法能够访问特化类的类型参数而不将其擦除，并且针对报告中的示例展示了该行为时，这项工作就完成了。