detect if __future__.annotations is actually needed

[hon-gyu]

Currently we seem to include from __future__ import annotations in all cases. But it should only be needed if (1) there are type declarations; and (2) the type declarations contain circular references (?)

• is the above understanding correct?
• is there a way to detect if it's needed?
  • one potential way: use ty to typecheck code without and with this import. if it fails without it and passes with it, it should be added.