Unexpected failed binary compatibility checks when upgrading Scala 3.x from 3.1.1 to 3.1.2

[plokhotnyuk]

1. https://github.com/plokhotnyuk/jsoniter-scala/runs/5997860125?check_suite_focus=true
2. https://github.com/plokhotnyuk/fast-string-interpolator/runs/5997843067?check_suite_focus=true

[danicheg]

We also get it in http4s.
https://github.com/http4s/http4s/runs/5994609791?check_suite_focus=true

[smarter]

You can ignore IncompatibleSignatureProblem where it goes from no generic signature (which mima writes <missing>) to some generic signature, but ideally mima should do that itself.

[raboof]

You can ignore IncompatibleSignatureProblem where it goes from no generic signature (which mima writes <missing>) to some generic signature, but ideally mima should do that itself.

That makes sense, though it doesn't help in the jsoniter case, since that also checks for forward compatibility. I'd rather still emit a warning when a generic signature disappears (since it's not necessarily a problem, but definitely surprising/suspicious).

It looks like in this case Scala 3.1.2 adds signatures for methods that aren't generic. I think we can safely disregard those when comparing signatures, since we first check the descriptor anyway. Proposing #695.