Add Commutative{Monad, FlatMap} instances for IdT (#2104)

typelevel · Dec 14, 2017 · d9c3c5b · d9c3c5b
1 parent cf36426
commit d9c3c5b
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Showing 2 changed files with 18 additions and 1 deletion.
diff --git a/core/src/main/scala/cats/data/IdT.scala b/core/src/main/scala/cats/data/IdT.scala
@@ -135,7 +135,17 @@ private[data] sealed trait IdTNonEmptyTraverse[F[_]] extends IdTTraverse[F] with
     fa.reduceRightTo(f)(g)
 }
 
-private[data] sealed abstract class IdTInstances6 {
+private[data] sealed abstract class IdTInstances8 {
+  implicit def catsDataCommutativeFlatMapForIdT[F[_]](implicit F: CommutativeFlatMap[F]): CommutativeFlatMap[IdT[F, ?]] =
+    new IdTFlatMap[F] with CommutativeFlatMap[IdT[F, ?]] { implicit val F0: CommutativeFlatMap[F] = F }
+}
+
+private[data] sealed abstract class IdTInstances7 extends IdTInstances8{
+  implicit def catsDataCommutativeMonadForIdT[F[_]](implicit F: CommutativeMonad[F]): CommutativeMonad[IdT[F, ?]] =
+    new IdTMonad[F] with CommutativeMonad[IdT[F, ?]] { implicit val F0: CommutativeMonad[F] = F }
+}
+
+private[data] sealed abstract class IdTInstances6 extends IdTInstances7 {
   implicit def catsDataContravariantMonoidalForIdT[F[_]](implicit F: ContravariantMonoidal[F]): ContravariantMonoidal[IdT[F, ?]] =
     new IdTContravariantMonoidal[F] { implicit val F0: ContravariantMonoidal[F] = F }
 }

diff --git a/tests/src/test/scala/cats/tests/IdTSuite.scala b/tests/src/test/scala/cats/tests/IdTSuite.scala
@@ -5,11 +5,18 @@ import cats.data.{Const, IdT, NonEmptyList}
 import cats.kernel.laws.discipline.{OrderTests, EqTests}
 import cats.laws.discipline._
 import cats.laws.discipline.arbitrary._
+import Helpers.CSemi
 
 class IdTSuite extends CatsSuite {
 
   implicit val iso = SemigroupalTests.Isomorphisms.invariant[IdT[ListWrapper, ?]](IdT.catsDataFunctorForIdT(ListWrapper.functor))
 
+  checkAll("IdT[(CSemi, ?), Int]", CommutativeFlatMapTests[IdT[(CSemi, ?), ?]].commutativeFlatMap[Int, Int, Int])
+  checkAll("CommutativeFlatMap[IdT[(CSemi, ?), ?]]", SerializableTests.serializable(CommutativeFlatMap[IdT[(CSemi, ?), ?]]))
+
+  checkAll("IdT[Option, Int]", CommutativeMonadTests[IdT[Option, ?]].commutativeMonad[Int, Int, Int])
+  checkAll("CommutativeMonad[IdT[Option, ?]]", SerializableTests.serializable(CommutativeMonad[IdT[Option, ?]]))
+
   {
     implicit val F = ListWrapper.eqv[Option[Int]]