Composite sort key ergonomics about meteor HOT 1 OPEN

sealed trait CompositeValue2[A, +B]

final case class One[A](x: A) extends CompositeValue2[A, Nothing]

object CompositeValue2 {
  implicit def attrKey2Encoder[A, B](implicit
    A: DynamoStringEncoder[A]
  ): Encoder[CompositeValue2[A, B]] =
    Encoder[String]
      .contramap { case One(x) =>
        A.toDynamoString(x)
      }
}