Added instances and reolution tests for Id. Removed unneeded type

parameters.
typelevel · Mar 9, 2018 · fba0f7a · fba0f7a
1 parent e63a7e3
commit fba0f7a
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Showing 2 changed files with 27 additions and 2 deletions.
diff --git a/core/src/main/scala/cats/data/WriterT.scala b/core/src/main/scala/cats/data/WriterT.scala
@@ -106,13 +106,20 @@ private[data] sealed abstract class WriterTInstances extends WriterTInstances0 {
       implicit val F0: Monad[F] = F
       implicit val L0: Monoid[L] = L
     }
+
+  implicit def catsDataTraverseForWriterTId[L](implicit F: Traverse[Id]): Traverse[WriterT[Id, L, ?]] =
+    catsDataTraverseForWriterT[Id, L]
 }
 
 private[data] sealed abstract class WriterTInstances0 extends WriterTInstances1 {
-  implicit def catsDataTraverseForWriterT[F[_], L, V](implicit F: Traverse[F]): Traverse[WriterT[F, L, ?]] =
+
+  implicit def catsDataTraverseForWriterT[F[_], L](implicit F: Traverse[F]): Traverse[WriterT[F, L, ?]] =
     new WriterTTraverse[F, L] {
       val F0: Traverse[F] = F
     }
+
+  implicit def catsDataFoldableForWriterTId[L](implicit F: Foldable[Id]): Foldable[WriterT[Id, L, ?]] =
+    catsDataFoldableForWriterT[Id, L]
 }
 
 private[data] sealed abstract class WriterTInstances1 extends WriterTInstances2 {
@@ -153,7 +160,7 @@ private[data] sealed abstract class WriterTInstances1 extends WriterTInstances2
   implicit def catsDataMonoidForWriterTId[L:Monoid, V:Monoid]: Monoid[WriterT[Id, L, V]] =
     catsDataMonoidForWriterT[Id, L, V]
 
-  implicit def catsDataFoldableForWriterT[F[_], L, V](implicit F: Foldable[F]): Foldable[WriterT[F, L, ?]] =
+  implicit def catsDataFoldableForWriterT[F[_], L](implicit F: Foldable[F]): Foldable[WriterT[F, L, ?]] =
     new WriterTFoldable[F, L]{
       val F0: Foldable[F] = F
     }
@@ -168,6 +175,9 @@ private[data] sealed abstract class WriterTInstances2 extends WriterTInstances3
 
   implicit def catsDataSemigroupForWriterTId[L:Semigroup, V:Semigroup]: Semigroup[WriterT[Id, L, V]] =
     catsDataSemigroupForWriterT[Id, L, V]
+
+  implicit def catsDataComonadForWriterTId[L](implicit F: Comonad[Id]): Comonad[WriterT[Id, L, ?]] =
+    catsDataComonadForWriterT[Id, L]
 }
 
 private[data] sealed abstract class WriterTInstances3 extends WriterTInstances4 {

diff --git a/tests/src/test/scala/cats/tests/WriterTSuite.scala b/tests/src/test/scala/cats/tests/WriterTSuite.scala
@@ -373,28 +373,43 @@ class WriterTSuite extends CatsSuite {
   {
     // F has a Foldable and L has a Monoid
     implicit val L: Monoid[ListWrapper[Int]] = ListWrapper.monoid[Int]
+    Foldable[Const[String, ?]]
     Foldable[WriterT[Const[String, ?], ListWrapper[Int], ?]]
 
     checkAll("WriterT[Const[String, ?], ListWrapper[Int], ?]", FoldableTests[WriterT[Const[String, ?], ListWrapper[Int], ?]].foldable[Int, Int])
     checkAll("Foldable[WriterT[Const[String, ?], ListWrapper[Int], ?]]", SerializableTests.serializable(Foldable[WriterT[Const[String, ?], ListWrapper[Int], ?]]))
+
+    Foldable[Id]
+    Foldable[WriterT[Id, ListWrapper[Int], ?]]
+    Foldable[Writer[ListWrapper[Int], ?]]
   }
 
   {
     // F has a Traverse and L has a Monoid
     implicit val L: Monoid[ListWrapper[Int]] = ListWrapper.monoid[Int]
+    Traverse[Const[String, ?]]
     Traverse[WriterT[Const[String, ?], ListWrapper[Int], ?]]
 
     checkAll("WriterT[Const[String, ?], ListWrapper[Int], ?]", TraverseTests[WriterT[Const[String, ?], ListWrapper[Int], ?]].traverse[Int, Int, Int, Int, Option, Option])
     checkAll("Traverse[WriterT[Const[String, ?], ListWrapper[Int], ?]]", SerializableTests.serializable(Traverse[WriterT[Const[String, ?], ListWrapper[Int], ?]]))
+
+    Traverse[Id]
+    Traverse[WriterT[Id, ListWrapper[Int], ?]]
+    Traverse[Writer[ListWrapper[Int], ?]]
   }
 
   {
     // F has a Comonad and L has a Monoid
     implicit val L: Monoid[ListWrapper[Int]] = ListWrapper.monoid[Int]
+    Comonad[(String, ?)]
     Comonad[WriterT[(String, ?), ListWrapper[Int], ?]]
 
     checkAll("WriterT[(String, ?), ListWrapper[Int], ?]", ComonadTests[WriterT[(String, ?), ListWrapper[Int], ?]].comonad[Int, Int, Int])
     checkAll("Comonad[WriterT[(String, ?), ListWrapper[Int], ?]]", SerializableTests.serializable(Comonad[WriterT[(String, ?), ListWrapper[Int], ?]]))
+
+    Comonad[Id]
+    Comonad[WriterT[Id, ListWrapper[Int], ?]]
+    Comonad[Writer[ListWrapper[Int], ?]]
   }
 
   checkAll("WriterT[Option, Int, ?]", CommutativeMonadTests[WriterT[Option, Int, ?]].commutativeMonad[Int, Int, Int])