Circe with generic types

GenericCirce.scala

import io.circe._
import io.circe.parser._
import io.circe.syntax._
import io.circe.generic.decoding._
import io.circe.generic.encoding._
import io.circe.generic.semiauto._

case class GenericModel[Payload](payload: Payload, value: String)

case class TestPayload()

case class RealPayload()

trait CirceCodec[P] {
  type Payload = P

  implicit def dec0: Decoder[Payload]

  implicit def enc0: Encoder[Payload]

  implicit def dec1: Decoder[GenericModel[Payload]]

  implicit def enc1: Encoder[GenericModel[Payload]]
}

class CirceCodecPolyImpl
[
P: DerivedObjectEncoder : DerivedDecoder
] extends CirceCodec[P] {

  implicit def dec0: Decoder[Payload] = deriveDecoder

  implicit def enc0: Encoder[Payload] = deriveEncoder

  implicit def dec1: Decoder[GenericModel[Payload]] = deriveDecoder

  implicit def enc1: Encoder[GenericModel[Payload]] = deriveEncoder
}

object RealCodec extends CirceCodecPolyImpl[RealPayload]

object TestCodec extends CirceCodecPolyImpl[TestPayload]


object Test {
  def test1(): Unit = {
    import RealCodec._
    println(parse(GenericModel[RealPayload](RealPayload(), "test1").asJson.noSpaces))
  }

  def test2(): Unit = {
    import TestCodec._
    println(parse(GenericModel[TestPayload](TestPayload(), "test2").asJson.noSpaces))
  }
}

Test.test1()
Test.test2()