Stack overflow with recursive callables

[correctmost]

Summary

ty crashes when checking this code:

from typing import Callable

def fn[**T, U](c: Callable[T, U]) -> Callable[T, U]:
    return c

fn(fn)

thread '<unknown>' (2580764) has overflowed its stack
fatal runtime error: stack overflow, aborting

Version

a15bc9c249 w/ astral-sh/ruff@b36ff75a2

[carljm]

Ha, nice. Thanks for the report!