kleisli-contra.scala

import cats._
import cats.data._
import cats.implicits._

object KleisliReader {
  val k = Kleisli[Id, Int, String](i => (i + 1).toString)
  
  Contravariant[Reader[?, String]]      // not found
  Contravariant[Kleisli[Id, ?, String]] // not found

  val j: Kleisli[Id, (Int, Int), String] =
    k.contramap { case (s: Int, t: Int) => s } // not found

  type K[A] = Kleisli[Id, A, String]
  val CK = Contravariant[K]
  val k2: K[Int] = k
  val j2: K[(Int, Int)] =
    CK.contramap(k2)(_._1)
    // k.contramap(_._1)                 // not found
}