Turning List[Int => Int] into Int => List[Int] with cosequence

gistfile1.txt

import scalaz.std.function._
import scalaz.syntax.functor._
import scalaz.Functor

/* https://gist.github.com/ceedubs/f8273ede78f86df7df7f shows we can do this with sequenceU.
 * Stephen Compall (S11001001) pointed out that cosequence can do this without requiring a
 * Traverse instance of the outer type by using the Distributive instance of the inner type.
 * (It still requires a Functor instance of the outer type, but many types such as Task, Future,
 * etc have Functor but not Traverse.)
 */

// proving we don't need the Traverse instance for List
implicit val listFunctor: Functor[List] = scalaz.std.list.listInstance

val add1: Int => Int = _ + 1
val times2: Int => Int = _ * 2
val squared: Int => Int = n => n * n
// we have to help the compiler out with cosequence :(
val combined: Int => List[Int] = List(add1, times2, squared).cosequence[({type l[a]= Int => a})#l, Int]

combined(4) // List(5, 8, 16)