Decorator reported as untyped when unknown type appears

[hmc-cs-mdrissi]

Describe the bug

from collections.abc import Callable
from typing import TypeVar

from lib import Node

T = TypeVar("T")

Callback = Callable[[T], None]

def dec(*x: str) -> Callable[[Callback[T]], Callback[T]]:
    ...

@dec("")
def foo(x: Node):
    ...

lib is intentionally an unknown name as bug is specific to function with Unknown annotation (any untyped library in real use case).

This code produces an error recently of,

Untyped function decorator obscures type of function

But if I change Node to object the code type checks fine. The decorator is fully annotated, but Unknown in function confuses it somehow.

Other strange thing is this issue requires type alias Callback. If I inline alias the error goes away.

VS Code extension or command-line pyright 1.1.369

[erictraut]

This is included in pyright 1.1.370