Shadow implicits

shadowing.scala

  package specsy {
    trait Expectable[A]
    trait MatchResult[A]
    trait Matcher[-T] { outer =>
      def apply[S <: T](t: Expectable[S]): MatchResult[S]
    }
    object Matchers {
      def oneMatcher[S1]: Matcher[S1] = OneMatcher.asInstanceOf[Matcher[S1]]
      def twoMatcher[S1, S2]: Matcher[(S1, S2)] = TwoMatcher.asInstanceOf[Matcher[(S1, S2)]]
    }
    object OneMatcher extends Matcher[Any] { def apply[S <: Any](t: Expectable[S]): MatchResult[S] = ??? }
    object TwoMatcher extends Matcher[(Any, Any)] { def apply[S <: (Any, Any)](t: Expectable[S]): MatchResult[S] = ??? }
    trait Cv { outer =>
      def zipf[T1,T2, S1,S2](m1: (=>T1) => Matcher[S1],m2: (=>T2) => Matcher[S2]): (=>(T1,T2)) => Matcher[(S1,S2)] = {
        x => Matchers.twoMatcher[S1, S2]
      }
      implicit class TupleMatcher2[T1,T2](t: (T1,T2)) {
        def zipf[S1,S2](m1: (=>T1) => Matcher[S1], m2: (=>T2) => Matcher[S2]): Matcher[(S1,S2)] =
          outer.zipf(m1,m2)(t)
      }
    }
    trait Off extends Cv {
      implicit class nottm2[T1, T2](val c: Any) {
        def zipf[S1,S2](m1: (=>T1) => Matcher[S1], m2: (=>T2) => Matcher[S2]): Matcher[(S1,S2)] = ???
      }
      /*
      implicit class nottm2(val c: Any) {
        def zipf[T1,T2,S1,S2](m1: (=>T1) => Matcher[S1], m2: (=>T2) => Matcher[S2]): Matcher[(S1,S2)] = ???
      }
      */
      //override def TupleMatcher2[T1,T2](t: (T1,T2)) = super.TupleMatcher2(t)
    }
    object OK extends App with Cv {
      val t = (42, 27)
      def m(n: => Int): Matcher[Int] = Matchers.oneMatcher[Int]
      println(t.zipf(m, m))
    }
    /*
    */
    object DNC extends App with Off {
      val t = (42, 27)
      def m(n: => Int): Matcher[Int] = Matchers.oneMatcher[Int]
      println(t.zipf(m, m))
    }
  }