CoflatMap Instance for Applicative

core/src/main/scala/cats/Applicative.scala

@@ -207,6 +207,28 @@ object Applicative {
    */
   implicit def catsApplicativeForArrow[F[_, _], A](implicit F: Arrow[F]): Applicative[F[A, ?]] =
     new ArrowApplicative[F, A](F)
+
+
+  /**
+   * Creates a CoflatMap for an Applicative `F`.
+   * Cannot be implicit in 1.0 for Binary Compatibility Reasons
+   *
+   * Example:
+   * {{{
+   * scala> import cats._
+   * scala> import cats.implicits._
+   * scala> val fa = Some(3)
+   * fa: Option[Int] = Some(3)
+   * scala> Applicative.coflatMap[Option].coflatten(fa)
+   * res0: Option[Option[Int]] = Some(Some(3))
+   * }}}
+   */
+  def coflatMap[F[_]](implicit F: Applicative[F]): CoflatMap[F] =
+    new CoflatMap[F] {
+      def coflatMap[A, B](fa: F[A])(f: F[A] => B): F[B] = F.pure(f(fa))
+      def map[A, B](fa: F[A])(f: A => B): F[B] = F.map(fa)(f)
+    }
+
 }
 
 private[cats] class ApplicativeMonoid[F[_], A](f: Applicative[F], monoid: Monoid[A]) extends ApplySemigroup(f, monoid) with Monoid[F[A]] {

tests/src/test/scala/cats/tests/ApplicativeSuite.scala

@@ -2,6 +2,9 @@ package cats
 package tests
 
 import cats.Applicative
+import cats.data.{Validated, Const}
+import cats.laws.discipline.arbitrary._
+import cats.laws.discipline.CoflatMapTests
 
 
 class ApplicativeSuite extends CatsSuite {
@@ -36,4 +39,14 @@ class ApplicativeSuite extends CatsSuite {
     }
   }
 
+  implicit val listwrapperApplicative = ListWrapper.applicative
+  implicit val listwrapperCoflatMap = Applicative.coflatMap[ListWrapper]
+  checkAll("Applicative[ListWrapper].coflatMap", CoflatMapTests[ListWrapper].coflatMap[String, String, String])
+
+  implicit val validatedCoflatMap = Applicative.coflatMap[Validated[String, ?]]
+  checkAll("Applicative[Validated].coflatMap", CoflatMapTests[Validated[String, ?]].coflatMap[String, String, String])
+
+  implicit val constCoflatMap = Applicative.coflatMap[Const[String, ?]]
+  checkAll("Applicative[Const].coflatMap", CoflatMapTests[Const[String, ?]].coflatMap[String, String, String])
+
 }