a.scala

package p {
  trait Show[-A] {
    def show(x: A): String
  }

  trait Direct[+A]
  trait Consecutive[+A] extends Direct[A]
  final class Closed[+A]() extends Consecutive[A]

  trait LowPriorityShow {
    implicit def showDirect[A]: Show[Direct[A]] =
      new Show[Direct[A]] { def show(x: Direct[A]) = "Direct[A]" }
  }

  object Run {
    def main(args: Array[String]): Unit = {
      println(showsAs(nrange(0, 3)))
    }
  }
}


package object p extends p.LowPriorityShow {
  def nrange(s: Int, e: Int): Closed[Int] = new Closed[Int]()
  def showsAs[A: Show](x: A): String      = implicitly[Show[A]].show(x)

  implicit def showConsecutive[A, CC[X] <: Consecutive[X]]: Show[CC[_ <: A]] =
    new Show[CC[_ <: A]] { def show(x: CC[_ <: A]) = "CC[_ <: A]" }
}

output.txt

% ./run.sh
Typelevel...
Direct[A]

Scala...
CC[_ <: A]

run.sh

#!/usr/bin/env bash
#

echo "Typelevel..."

CP="$(coursier fetch org.typelevel:scala-compiler:2.12.1 | paste -sd: -)"

rm -rf ./p
java -cp "$CP" scala.tools.nsc.Main -usejavacp -nowarn *.scala
java -cp "$CP" scala.tools.nsc.MainGenericRunner -usejavacp p.Run

echo ""
echo "Scala..."

rm -rf ./p
scalac-2.12 -nowarn *.scala
scala-2.12 p.Run