Large number of MiMa generic signature incompatibles for `scala-library` 3.8.0

[WojciechMazur]

There are apparently 1169 MiMa generic signature incompatibilities when comparing 3.8.0-RC2 against 3.7.3-fatlib (combined scala-library:2.13.17 and scala3-library_3:3.7.3)

https://gist.github.com/WojciechMazur/eb822f18f3b5dbe11b067a7e54b0bbe7

These should be checked and probably fixed - the generic singatures should not change between old and new stdlib

In current main we're no longer comparing against 3.3 LTS (this should be restored eventually) and binary compatibility is only guarded by transitivity rule (3.7.4 was compatibile with 3.3 LTS, so 3.8.0 needs to be compatible with 3.7.4)

Compiler version

3.8.0-RC2

Reproduction steps

• checkout release-3.8.0
• add mimaReportSignatureProblems := true to scala-library-bootstrapped project
• sbt scala-library-bootstrapped/mimaReportBinaryIssues

Expectation

Diff should be minimal or exactly the same

[hamzaremmal]

I'm aware of all of these and I'm fixing them one by one. These are not surprises. Some of them are improvements we could do but they are not fundamentally wrong. So this is not a priority, the priority is to fix the one that breaks Java compatibility (aka what @tanishiking is doing for akka/pekko).

[hamzaremmal]

Also, I don't recall exactly, but I believe there are some occasions where Scala 3 does better than Scala 2 so having these failures doesn't mean they should all be fixed. It only means they should all be analysed as we are currently (and having been) doing.