Typed.scala

  trait Instance[T] {
    def t: T
  }
  object Instance   {
    def apply[T](v: T): Instance[T] = new Instance[T] { override def t: T = v }
  }

  sealed trait Typed {
    type T
  }
  sealed trait TypedValue extends Typed {
    def value: T
  }
  object Typed {
    def instance(typed: Typed): Instance[typed.T] =
      typed match {
        case t: TypedValue => Instance(t.value) // To make this compile: Instance(t.value.asInstanceOf[typed.T])
      }
  }