mypy typechecks that just fine[1]. However, I think that's possibly a bug :-) -- I agree that narrowing a literal via subclassing is unsound. That's why the ex

mypy typechecks that just fine[1]. However, I think that's possibly a bug :-) -- I agree that narrowing a literal via subclassing is unsound. That's why the example in the blog used `str` for the superclass, not the closure of all `Literal` variants. (I use this pattern pretty extensively in Python codebases that are typechecked with mypy, and I haven't run into many issues with mypy failing to understand the variant shapes -- the exception to this so far has been with `RootModel`, where mypy has needed Pydantic's mypy plugin[2] to understand the relationship between the "root" type and its underlying union. But it's possible that this is essentially unsound as well.) [1]: https://mypy-play.net/?mypy=latest&python=3.12&gist=f35da62ec4ac59f06360a758ca5f58f6 https://mypy-play.net/?mypy=latest&python=3.12&gist=f35da62e... [2]: https://docs.pydantic.dev/latest/integrations/mypy/ https://docs.pydantic.dev/latest/integrations/mypy/