OrType

OrType.scala

object Type {

  class |:|[A, B]

  implicit def orTypeA[A, B](implicit a: A): |:|[A, B] = new |:|[A, B]

  implicit def orTypeB[A, B](implicit b: B): |:|[A, B] = new |:|[A, B]

  type \:/[T, U] = {type λ[X] = (X <:< T) |:| (X <:< U)}

  object Test {

    case class One(x: Int)

    case class Two(x: Int)

    case class Three(x: Int)

    case class Wrap[A: (One \:/ Two)#λ](a: A)

    val w1 = Wrap(One(1))

    val w2 = Wrap(Two(2))

    // does not compile
    val w3 = Wrap(Three(3))
  }

}