Claim Monad for X509 Certificates - having trouble running map on it

RequestHeader.scala

import java.net.URI
import scalaz.concurrent.Promise
import scalaz._
import Scalaz._
import language.implicitConversions


case class Cert(cn: String, pubKey: BigInt, webids: List[URI] )

trait RequestHeader {
  type Certificates = Cert

  def cert: Promise[Claim[_,Certificates]]

}

sealed trait Level
object Truth extends Level
object PubKeyVerified extends Level


trait Claim[L <: Level, S] {
  protected val statements: S

  val level: L

  def verify[L2 <: Level, S2](implicit verify: Verificator[L, S, L2, S2]): Claim[L2, S2] = {
    verify(this)
  }

  def st(implicit ev: L =:= Truth.type) = statements

}

trait Verificator[L<: Level,S,L2<:Level,S2] {
  def apply(s: Claim[L,S]): Claim[L2,S2]
}

object Claim {

  implicit val level: Truth.type = Truth

  implicit def unapplyClaim[TC[_[_]], A0 <: Level, B0](implicit TC0: TC[({type λ[α] = Claim[A0, α]})#λ]): Unapply[TC, Claim[A0, B0]] {
    type M[X] = Claim[A0, X]
    type A = B0
  } = new Unapply[TC, Claim[A0, B0]] {
    type M[X] = Claim[A0, X]
    type A = B0
    def TC = TC0
    def apply(ma: Claim[A0, B0]) = ma
  }

  implicit def ClaimMonad[L <: Level](implicit lvl: L): Monad[({type f[+a] = Claim[L, a]})#f] =
   new Monad[({type f[+a] = Claim[L, a]})#f] {

      def point[A](a: => A) = new Claim[L,A] {
        protected val statements : A = a

        val level: L = lvl

      }

      def bind[A, B](fa: Claim[L,A])(f: A => Claim[L,B]) = f(fa.statements)
    }

}

object Test {

    import Claim._

    implicitly[Truth.type]
    val m = Monad[({type f[+a] = Claim[Truth.type, a]})#f]
    val p = m.point(Cert("Henry Story",BigInt(123456789),List(new java.net.URI("http://bblfish.net/#hjs"))))

    val q = p.map(_.cn)
    q.st

}