Problems in erasure

[DarkDimius]

./out/dotty/tools/dotc/core/Phases.class

    default public Object atPhase(Phase phase, Function1 op) {
        return this.atPhase((Phase)BoxesRunTime.boxToInteger((int)phase.id()), op);
    }

is obviously going to fail with java.lang.Integer cannot be cast to dotty.tools.dotc.core.Phases$Phase.

Unfortunatelly, running dotty with isDerivedValueClass set to false does not work, so this blocks bootstrap.

[odersky]

Here's a minimized test case:

trait Periods { self: Context =>

  def atPhase(id: Int): Unit = println(s"atPhase: $id")

}

trait Phases { self: Context =>
  case class Phase(id: Int)
  def atPhase(phase: Phase): Unit = atPhase(phase.id)
}

trait Context extends Phases with Periods

object Test extends Context {

  def main(args: Array[String]) = atPhase(new Phase(2))

}

[odersky]

As the test case shows it has actually nothing to do with value classes. I found the real problem. Fix coming shortly.