gistfile1.scala

object SJ extends App {

  trait Getter[T] {
    def get(s: String): T
  }

  object Getter {

    implicit val getInt = new Getter[Int] {
      def get(s: String) = s.toInt // unsafe
    }

    implicit val getString = new Getter[String] {
      def get(s: String) = s
    }
  }

  def get[T: Getter](s: String): T = implicitly[Getter[T]].get(s)

  case class A(s: String)
  case class B(n: Int)

  class Foo[T: Getter](s: String) {
    val t: T = get(s)
  }

//  no compile (ambiguous implicits)
//  A(get("foo")) 
//  B(get("foo"))

  A(get[String]("foo"))
  B(get[Int]("foo"))

}