```scala object Test { case class Tuple2K[H[_], T[_], X](h: H[X], t: T[X]) trait TC[A] implicit def case1[F[_]](implicit t: => TC[F[Any]]): TC[Tuple2K[[_] => Any, F, Any]] = ??? implicit def case2[A, F[_]](implicit r: TC[F[Any]]): TC[A] = ??? implicitly[TC[Int]] // java.lang.IndexOutOfBoundsException: 0 } ```