We should emit a diagnostic when we see conflicting declared types of attributes, either between the declaration in the class body and declarations in a method, or between annotated assignments in different methods. We have existing tests for this scenario (see TODO comments):

https://github.com/astral-sh/ruff/blob/eb08345fd5434ed3db243233df6dd91757a6af3b/crates/red_knot_python_semantic/resources/mdtest/attributes.md?plain=1#L212-L226

part of: astral-sh/ruff#14164