Alex Waygood 0639da2552 [ty] ~T should never be assignable to T (#20606) ... ## Summary Currently we do not emit an error on this code: ```py from ty_extensions import Not def f[T](x: T, y: Not[T]) -> T: x = y return x ``` But we should do! `~T` should never be assignable to `T`. This fixes a small regression introduced in 14fe1228e7 (diff-8049ab5af787dba29daa389bbe2b691560c15461ef536f122b1beab112a4b48aR1443-R1446), where a branch that previously returned `false` was replaced with a branch that returns `C::always_satisfiable` -- the opposite of what it used to be! The regression occurred because we didn't have any tests for this -- so I added some tests in this PR that fail on `main`. I only spotted the problem because I was going through the code of `has_relation_to_impl` with a fine toothcomb for https://github.com/astral-sh/ruff/pull/20602 😄		2025-10-02 07:52:47 +01:00
..
legacy	[ty] ~T should never be assignable to T (#20606)	2025-10-02 07:52:47 +01:00
pep695	[ty] ~T should never be assignable to T (#20606)	2025-10-02 07:52:47 +01:00
builtins.md	[ty] Support using legacy typing aliases for generic classes in type annotations (#18404)	2025-06-03 12:09:51 +01:00
scoping.md	[ty] Use typing.Self for the first parameter of instance methods (#20517)	2025-09-29 21:08:08 +02:00