One of the many workarounds for "implicit type parameters" in Scala

HasKF.scala

class HasKF[F[_]] private {
  type KF[A, B] = Kleisli[F, A, B]
}

object HasKF {
  private val s: HasKF[Id] = new HasKF[Id]
  def apply[F[_]]: HasKF[F] = s.asInstanceOf[HasKF[F]]
}

class AService[F[_] : Applicative] {
  val x: HasKF[F]#KF[String, Int] = Kleisli.pure(10)
}

object AService {
  def main(args: Array[String]): Unit = {
    println(new AService[Id].x("hello"))
  }
}