hybridComponents.scala

trait AuthRepoComponent {
  val authRepo: AuthRepo
}

trait AuthRepoComponentImpl extends AuthRepoComponent {
  val authRepo: AuthRepo = new AuthRepoImpl
}

trait AuthServComponent {
  val authServ: AuthServ
}

trait AuthServComponentImpl extends AuthServComponent {
  self: AuthRepoComponent => // this is the self-type
  val authServ: AuthServ = new AuthServ(authRepo)
}