Ooh. I just found out about vermin: https://github.com/netromdk/vermin I wonder if pants could use that to recommend interpreter_constraints... Maybe in tailor?

Would that work as expected though? Some slices of code work on 3.6 while some are 3.7, etc... But overall my ICs are just 3.9

Dunno. Next thing to do is try it on some code bases and see what it says.

Don't you kinda already know what your own code supports though?

Not really. I know what it should support and what we're testing on. Also, when I pick up new code bases, I don't know if what they say is accurate.