Sad days. LGTM.

After applying #2414, the test case in eed3si9n@1f25cdf compiles and run successfully, however I was able to reproduce the problem by changing the testcase to involve a derived value class:

package example

class VC(val self: Int) extends AnyVal

class A {
  case class B(x: VC)
  def c = B
}
object A {
  def main(args: Array[String]): Unit = {
    (new A).c
  }
}

I suggest using this as a testcase instead. I can't help with the actual bug but my guess is that it has something to do with exitingPostErasure and scala/scala@6dd1495 might help, cc @adriaanm

It looks like using the changes in scala/scala@6dd1495 fixes the issue for both test cases in this ticket. Do we want to revert #2261 altogether or apply the fix by @adriaanm?

I created a branch with the test cases and the fix by @adriaanm: 0.13...Duhemm:fix-2411

@Duhemm If you can fix this, I am ok with keeping this feature. Could you test with the projects mentioned by the original tickets:

https://travis-ci.org/xuwei-k/Play20/jobs/104261656#L497
https://travis-ci.org/xuwei-k/scalikejdbc/jobs/104293183#L1193
https://travis-ci.org/seratch/skinny-framework/jobs/104275385#L2107
https://travis-ci.org/xuwei-k/cats/jobs/104294044#L2702

@eed3si9n Of course.

If possible please forward fix. Reverts are more work in this forward-porting, multi-repo world.

Closing this in favor of #2418