Slick 2.0 - 通用枚举映射器

Question

我在Play应用程序中从Slick 1.0升级到Slick 2.0时遇到问题。

在我的应用中，我有一些用户定义的类型示例：

sealed trait UserStatus

case object NewUser extends UserStatus
case object ActiveUser extends UserStatus
case object BlockedUser extends UserStatus

object UserStatus extends SerializableEnum[UserStatus] {
  def mapping = Map[String, UserStatus](
    "NEW" -> NewUser,
    "ACTIVE" -> ActiveUser,
    "BLOCKED" -> BlockedUser
  )
}

和光滑1.0的通用映射器：

trait SerializableEnum[T] {
  def mapping: Map[String, T]

  def reverseMapping = mapping.map(_.swap)

  implicit def enumWrites = new Writes[T] {
    def writes(o: T): JsValue = JsString(reverseMapping(o))
  }

  implicit val enumReads = new Reads[T] {
    def reads(json: JsValue): JsResult[T] = json match {
      case JsString(s) => JsSuccess(mapping(s))
      case _ => JsError("Enum type should be of proper type")
    }
  }
  implicit val enumTypeMapper = MappedTypeMapper.base[T, String](reverseMapping, mapping)
}

迁移到Slick 2.0后，新的映射器无效：

trait SerializableEnum[T] {
  def mapping: Map[String, T]

  def reverseMapping:Map[T,String] = mapping.map(_.swap)

  implicit def enumWrites = new Writes[T] {
    def writes(o: T): JsValue = JsString(reverseMapping(o))
  }

  implicit val enumReads = new Reads[T] {
    def reads(json: JsValue): JsResult[T] = json match {
      case JsString(s) => JsSuccess(mapping(s))
      case _ => JsError("Enum type should be of proper type")
    }
  }
  implicit val enumTypeMapper = MappedColumnType.base[T, String](reverseMapping, mapping)
}

编译说：

No ClassTag available for T

无法为特征定义ClassTag类型。有人知道如何解决它吗？

我为此准备了示例应用： https://github.com/mgosk/slick-test