trait Xtractor[X]{
    type Repr
    def xtractTypeClass[TC[_]](implicit tc: TC[Repr]): TC[X]
  }
object Xtractor {
    type Aux[A, B] = Xtractor[A] {type Repr = B}
    implicit def estaticoXtractor[A, B](implicit c: Coercible[A, B]): Xtractor.Aux[B, A] = new Xtractor[B] {
      override type Repr = A
      override def xtractTypeClass[TC[_]](implicit tc: TC[A]): TC[B] = ???
    }
  }

case class Name(s: String)
object Name {
    implicit def encoder(implicit xtractor: Xtractor[Name]): Encoder[Name] = xtractor.xtractTypeClass[Encoder]
  }