Regression test for https://github.com/astral-sh/ty/issues/2243 Reduced to 20 lines. The crash requires this specific combination: 1. A TypeVar with a forward-reference union bound 2. A Callable type alias using that TypeVar 3. A Protocol using Self returning another Protocol with that TypeVar 4. A subclass Protocol inheriting from the parent with the TypeVar 5. Another Protocol using ExprT (bounded by forward ref) in a method