mypy

cc1bcc9c - Properly expand type in generic class with Self and TypeVar with values (#14491)

Properly expand type in generic class with Self and TypeVar with values (#14491) Fixes #14374 It looks like we need to special-case `Self` in `expand_type()` to support it in generics over `TypeVar` with values, since `Self` is the only type variable that can legitimately have other type variables in its upper bound.