NewTypesV2.scala

import scala.reflect.ClassTag

object Test {
  type Flags = Flags.Type
  trait Flags1 {
    import Flags._
    type Type <: Int with Tag$$1
  }
  object Flags extends Flags1 {
    trait Tag$$1 extends Any
    object Impl {
      def apply(value: Int): Type = value.asInstanceOf[Type]
      def unwrap(value: Type): Int = value.asInstanceOf[Int]
      def subst[F[_]](value: F[Int]): F[Type] = value.asInstanceOf[F[Type]]
    }
    
    implicit val equiv: ClassTag[Type] = Impl.subst[ClassTag](implicitly[ClassTag[Int]])
  }
  
  type Opaque = Opaque.Type
  trait Opaque1 {
    import Opaque._
    type Base$$1
    type Type <: Base$$1 with Tag$$1
  }
  object Opaque extends Opaque1 {
    trait Tag$$1 extends Any
    object Impl {
      def apply(value: Int): Type = value.asInstanceOf[Type]
      def unwrap(value: Type): Int = value.asInstanceOf[Int]
      def subst[F[_]](value: F[Int]): F[Type] = value.asInstanceOf[F[Type]]
    }
    
    implicit val equiv: ClassTag[Type] = Impl.subst[ClassTag](implicitly[ClassTag[Int]])
  }

  def main(args: Array[String]): Unit = {
  
    implicitly[Flags <:< Int]
    
    println(implicitly[ClassTag[Flags]].newArray(10))
    println(implicitly[ClassTag[Opaque]].newArray(10))

    val arr: Array[Flags] = Flags.Impl.subst[Array]((Array(1): Array[Int]))
    println(arr(0))       // 1
    println(arr.getClass) // class [I, which is int[] !

    val v: Flags = Flags.Impl.apply(1)
    println(v)            // 1
    println(v.getClass)   // java.lang.Integer
    
    val arr1: Array[Opaque] = Opaque.Impl.subst[Array]((Array(1): Array[Int]))
    println(arr1(0))       // 1
    println(arr1.getClass) // class [I, which is int[] !

    val v1: Opaque = Opaque.Impl.apply(1)
    println(v1)            // 1
    println(v1.getClass)   // java.lang.Integer
  }
}