自定义用户类型(枚举)的Scala slick查询比较会产生错误

编译时,我得到以下方法的错误：

def findCredentials(credentialType:CredentialType)(implicit session: Session): List[Credential] = {
    val query = for {
      c <- credentials if c.credentialType === credentialType
    } yield c
    query.list
}

这是错误：

[error] ... value === is not a member of         
scala.slick.lifted.Column[models.domain.enumeration.CredentialType.CredentialType]
[error]       c <- credentials if c.credentialType === credentialType

枚举代??码在这里：

object CredentialType extends Enumeration {
  type CredentialType = Value
  val Password,Token = Value
}

表定义如下：

case class Credential(id: Long,userId: Long,credentialType: CredentialType)

class Credentials(tag: Tag) extends Table[Credential](tag,"credential") {
  implicit val credentialTypeColumnType = MappedColumnType.base[CredentialType,String](
    { c => c.toString },{ s => CredentialType.withName(s)}
  )
  def id = column[Long]("id",O.PrimaryKey,O.AutoInc)
  def userId = column[Long]("user_id")
  def credentialType = column[CredentialType]("type")
  def * = (id,userId,credentialType) <> (Credential.tupled,Credential.unapply)
}

我已经搜索过其他一些问题,但它们要么不是光滑的2.x.x,要么不涉及枚举类型.

我的问题是,我是否需要在枚举类型的某处定义===运算符,或者使用我缺少的当前slick 2.0.0功能是否有更简单的方法？

谢谢