The major changes from the previous version are:

- Add InitVar to specify initialize-only fields.

This is the only feature that does not sit right with me. It looks very obscure and "hacky". From what I understand, we are supposed to use the field syntax to define constructor arguments. I'd argue that the name "initialize-only fields" is a misnomer, which only hides the fact that this has nothing to do with fields at all. Couldn't dataclassses just pass *args and **kwargs to __post_init__()? Type checkers need to be special-cases for InitVar anyway, couldn't they instead be special cased to look at __post_init__ argument types?

• As written above, InitVars look like fields, but aren't.
  
• InitVar goes against the established way to pass through arguments, *args and **kwargs. While type checking those is an unsolved problem, from what I understand, I don't think we should introduce a second way just for dataclasses.
• InitVars look like a way to satisfy the type checker without providing any benefit to the programmer. Even when I'm not interested in type checking, I have to declare init vars.
• InitVars force me to repeat myself. I have the InitVar declaration and then I have the repeat myself in the signature of __post_init__(). This has all the usual problems of repeated code.