Thanks for the feedback, Martin.
That's a good point about `office_number` being interpreted as a class variable. My intent was to match the semantics of dataclass, and this was simply a bug in the spec. I've updated the spec accordingly.
As for `InitVar`, none of the other libraries that I've reviewed have a similar concept (at least that I've noticed), so I didn't see a need to add support for custom `InitVar` classes. If one of these libraries decides to add support in the future, I would encourage them to use `dataclass.InitVar` rather than creating a new class with the same semantics.
-- Eric Traut Contributor to Pyright & Pylance Microsoft Corp.