Limitations of Early Definitions, a new feature in Scala 2.8

early-initialization.scala

trait Base {
  val abstractVal: String
  final val useAbstractVal = abstractVal
}

{
  class C1 extends Base {
    val abstractVal = "C1.abstractVal"
  }
  assert(new C1().useAbstractVal eq null)
}

{
  class C2 extends {
    val abstractVal = "C2.abstractVal"
  } with Base

  assert(new C2().useAbstractVal == "C2.abstractVal")
}

{
  trait T1 extends {
    val abstractVal = "T1.abstractVal"
  } with Base

  class C3 extends T1

  assert(new C3().useAbstractVal eq null) // why not == "T1.abstractVal" ?
}

{
  class T2 extends {
    val abstractVal = "T2.abstractVal"
  } with Base

  case object O1 extends T2

  assert(O1.useAbstractVal == "T2.abstractVal")
}