Rules pertaining to PEP 695

[Goldziher]

MyPy released support for PEP 695 generics: python/mypy#15238

It would be awesome to do any of the following:

1. get linting errors for code that uses older style generics (TypeVar, ParamSpec etc.) for Python 3.12+
2. get linting errors for code that uses newer style generics and should be backward compatible with lower Python versions
3. automagically upgrade older style generics to use the new syntax

I see that for point 3 there is an open related issue. This issue is about the underlying rust implementation for point 3, but does not cover points 1 and 2.

[charliermarsh]

We have some support for this already in https://docs.astral.sh/ruff/rules/non-pep695-type-alias/. I believe that rule does (1) and (3)?

[Goldziher]

We have some support for this already in https://docs.astral.sh/ruff/rules/non-pep695-type-alias/. I believe that rule does (1) and (3)?

I don't think so. I might be wrong but it seems to me like this rule is concerned with the TypeAlias type.

I am talking about the new generics style: https://peps.python.org/pep-0695/#summary-examples

[charliermarsh]

Thanks, you're right, that's my mistake. We may want to fold this into #4617, and just flesh out that issue a bit more.

[ntBre]

Cases (1) and (3) should now be handled by the rules UP046 and UP047 added in #15565, with a few caveats being tracked in #15642.

I think case (2) would be a good fit for the "pydowngrade" suggestion from #2501, so I'm closing this and making a comment there.