Names of all subtypes of a Scala ADT

TypeNames.scala

trait TypeNames[A] {
  def names: List[String]
}

object TypeNames {
  def of[A](implicit ev: TypeNames[A]) = ev.names

  implicit def forGenericThing[A, Repr <: Coproduct, Types <: HList](
    implicit gen: Generic.Aux[A, Repr],
    typeables: coproduct.LiftAll.Aux[Typeable, Repr, Types],
    toTraversable: hlist.ToTraversable.Aux[Types, List, Typeable[_]],
  ): TypeNames[A] = new TypeNames[A] {
    def names: List[String] = typeables.instances.toList.map(_.describe)
  }

}