gistfile1.scala

  implicit def shrinkCore[V](implicit s1: Shrink[V]): Shrink[Core[V]] = Shrink { c =>
    c match {
      case Var(_)               => Stream.empty
      case h: HardCore          => Stream.empty
      case App(f, x)            => Stream(f, x)
      // case class Let[+V](bindings: List[Scope[Byte, Core, V]], body: Scope[Byte, Core, V])
      case Let(bindings, body)  => Stream() // TODO: bindings, body
      // case class Case[+V](c: Core[V], branches: Map[Byte, (Byte, Scope[Byte, Core, V])], default: Option[Scope[Unit, Core, V]])
      case Case(c, branches, d) => Stream(c) // TODO: branches, default
      case Data(tag, fields)    => fields.toStream
      // case class LamDict[+V](body: Scope[Unit, Core, V])
      case LamDict(body)        => Stream() // TODO: body
      case AppDict(f, d)        => Stream(f, d)
    }
  }