On Sun, 2021-04-11 at 23:34 -0700, Larry Hastings wrote:

Your example was valid, and I think your workaround should be fine.  Do you have a use case for this, or is this question motivated purely by curiosity?

It took a few readings for me to understand the limitations in the PEP. My example and workaround were mostly for me to confirm I had read it correctly. 

It's fine to modify the __annotations__ dict after the creation of the class or module.  It's code that modifies "__annotations__" from within the class or module that is disallowed here.  Similarly for dataclasses; once it creates a class object, it can explicitly set and / or modify the annotations dict on that class.

Thanks. I think this clarification should be added to the PEP.