See related #122285

This behavior is pretty inconsistent for other attributes set in the class namespace:

>>> class X:
...     __name__ = 42
...     __module__ = 42
...     __qualname__ = "42"
...     __firstlineno__ = 42
...     __static_attributes__ = 42
...     
>>> X.__name__
'X'
>>> X.__module__
42
>>> X.__qualname__
'42'
>>> X.__firstlineno__
42
>>> X.__static_attributes__
()

Still, it's probably nicer to make this work the way this issue asks for. This can be fixed with the approach in #131550 if we do the same thing in class namespaces as we already do there for modules (assign __annotate__ early in class body execution). I'd wait for that one to be merged first and then apply the same change to class bodies.

This was actually already fixed by #132345, because now the compiler-generated __annotate__ function gets stored at a different key in the class dict. I will send a PR with a test case.

(You'll still get your name overwritten if you use the name __annotate_func__ in user code. Don't do that.)