Diamond inheritance with abstract type member overriding

diamond_abstract_type_override.scala

trait BaseImp
trait Base {
  type T <: BaseImp
  val TVal: T
}

trait Sub1Imp extends BaseImp {
  def x = 1
}
trait Sub1 extends Base {
  type T <: Sub1Imp
}
object Sub1 extends Sub1 {
  type T = Sub1Imp
  val TVal = new Sub1Imp {}
  def x = "Sub1x - " + TVal.x
}

trait Sub2Imp extends BaseImp {
  def x = 2
  def y = 3
}
trait Sub2 extends Base {
  type T <: Sub2Imp
  def x = "Sub2x - " + TVal.x
  def y = "Sub2y - " + TVal.y
}
object Sub2 extends Sub2 {
  type T = Sub2Imp
  val TVal = new Sub2Imp {}
}

trait DiamondSubImp extends Sub1Imp with Sub2Imp {
  override def x = super.x
  def z = 4
}
trait DiamondSub extends Sub1 with Sub2 {
  type T <: DiamondSubImp
  override def x = "DiamondSubx - " + TVal.x
  def z = "DiamondSubz - " + TVal.z
}
object DiamondSub extends DiamondSub {
  type T = DiamondSubImp
  val TVal = new DiamondSubImp {}
}

println(s"Sub1.x = ${Sub1.x}")
println(s"Sub2.x = ${Sub2.x}")
println(s"Sub2.y = ${Sub2.y}")
println(s"DiamondSub.x = ${DiamondSub.x}")
println(s"DiamondSub.y = ${DiamondSub.y}")
println(s"DiamondSub.z = ${DiamondSub.z}")