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For what it's worth, I (representing FastAPI) think this is a great idea. 🎉 More details about my support for this are below (feel free to skip them): Even if the proposed change requires modifications (or not), the current state is already very helpful, and it would be a huge improvement in the development experience using FastAPI/pydantic and other similar libraries. By being part of standard Python it would be more straightforward for different editors to implement support for this in a standard way. And by having this simple way to declare that "dataclass-like" behavior, more libraries could take advantage of these features from type annotations similar to dataclasses, and much better support from editors (constructor autocompletion and type checks). I could imagine several libraries that would benefit from this, even some that are way older than dataclasses, like SQLAlchemy, or also other future possible tools. As this is already available and usable with the "alternate form" in Pyright (VS Code/Pylance) it can be implemented right away in pydantic and others: https://github.com/samuelcolvin/pydantic/pull/2721 The benefits are immediately evident and would help a lot of users (see that PR for a screenshot of autocompletion in a constructor with type info). Note: I tried replying to this thread via email but it seems I still don't understand the caveats and tricks to properly use the mailing list system, and it ended up in a "new thread" with this same message (https://mail.python.org/archives/list/typing-sig@python.org/thread/JMROGUAGK...), sorry for that, it was intended only as a response here. All the best, Sebastián Ramírez