TypeVar with Callable

[Cologler]

from typing import Callable, TypeVar

T = TypeVar('T')

some_cache = []

def lazy(factory: Callable[[], T]):
    # do something ...
    def wrapper() -> T:
        return some_cache[factory]
    return wrapper

fac = lazy(lambda: 15)
value = fac()

Expected behaviour

value has type int.

Actual behaviour

value has no type.

[jakebailey]

We support TypeVar (see https://github.com/microsoft/python-language-server/blob/58da850a7d8f7d1dbda9d43a2d56945701b35e85/src/Analysis/Ast/Test/GenericsTests.cs).

I believe it's Callable that's the issue here. #535

[Cologler]

@jakebailey no sure about that:

from typing import TypeVar

T = TypeVar('T')
cache = {}

def convert(value: T) -> T:
    return cache[value]

ret = convert(15)

maybe the test case needs to be updated.

[MikhailArkhipov]

Moving @jakebailey's example to #1163. Original code requires speclaizing Callable which is part of #535.