Remove arrow instance

typelevel · Sep 11, 2017 · 995d451 · 995d451
1 parent 3151311
commit 995d451
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diff --git a/core/src/main/scala/cats/data/IndexedStateT.scala b/core/src/main/scala/cats/data/IndexedStateT.scala
@@ -2,7 +2,6 @@ package cats
 package data
 
 import cats.functor.{ Contravariant, Bifunctor, Profunctor, Strong }
-import cats.arrow.Arrow
 import cats.syntax.either._
 
 /**
@@ -252,16 +251,11 @@ private[data] sealed abstract class IndexedStateTInstances3 extends IndexedState
     new IndexedStateTBifunctor[F, SA] { implicit def F = F0 }
 }
 
-private[data] sealed abstract class IndexedStateTInstances4 extends IndexedStateTInstances5 {
+private[data] sealed abstract class IndexedStateTInstances4 {
   implicit def catsDataStrongForIndexedStateT[F[_], V](implicit F0: Monad[F]): Strong[IndexedStateT[F, ?, ?, V]] =
     new IndexedStateTStrong[F, V] { implicit def F = F0 }
 }
 
-private[data] sealed abstract class IndexedStateTInstances5 {
-  implicit def catsDataArrowForIndexedStateT[F[_], V](implicit F0: Monad[F], V0: Monoid[V]): Arrow[IndexedStateT[F, ?, ?, V]] =
-    new IndexedStateTArrow[F, V] { implicit def F = F0; implicit def V = V0 }
-}
-
 // To workaround SI-7139 `object State` needs to be defined inside the package object
 // together with the type alias.
 private[data] abstract class StateFunctions {
@@ -337,28 +331,6 @@ private[data] sealed abstract class IndexedStateTStrong[F[_], V] extends Indexed
     first(fa).dimap((_: (C, A)).swap)(_.swap)
 }
 
-private[data] sealed abstract class IndexedStateTArrow[F[_], V] extends IndexedStateTStrong[F, V] with Arrow[IndexedStateT[F, ?, ?, V]] {
-  implicit def F: Monad[F]
-  implicit def V: Monoid[V]
-
-  def lift[A, B](f: A => B): IndexedStateT[F, A, B, V] =
-    IndexedStateT { a =>
-      F.pure((f(a), V.empty))
-    }
-
-  def id[A]: IndexedStateT[F, A, A, V] =
-    IndexedStateT.pure(V.empty)
-
-  def compose[A, B, C](f: IndexedStateT[F, B, C, V], g: IndexedStateT[F, A, B, V]): IndexedStateT[F, A, C, V] =
-    IndexedStateT { a =>
-      F.flatMap(g.run(a)) { case (b, va) =>
-        F.map(f.run(b)) { case (c, vb) =>
-          (c, V.combine(va, vb))
-        }
-      }
-    }
-}
-
 private[data] sealed abstract class IndexedStateTMonad[F[_], S] extends IndexedStateTFunctor[F, S, S] with Monad[IndexedStateT[F, S, S, ?]] {
   implicit def F: Monad[F]
 

diff --git a/tests/src/test/scala/cats/tests/IndexedStateTTests.scala b/tests/src/test/scala/cats/tests/IndexedStateTTests.scala
@@ -1,7 +1,6 @@
 package cats
 package tests
 
-import cats.arrow.Arrow
 import cats.data.{State, StateT, IndexedStateT, EitherT}
 import cats.functor.{Contravariant, Bifunctor, Profunctor, Strong}
 import cats.kernel.instances.tuple._
@@ -322,16 +321,6 @@ class IndexedStateTTests extends CatsSuite {
     Strong[IndexedStateT[ListWrapper, ?, ?, Int]]
   }
 
-  {
-    implicit val F: Monad[ListWrapper] = ListWrapper.monad
-    implicit val FS: Arrow[IndexedStateT[ListWrapper, ?, ?, Int]] = IndexedStateT.catsDataArrowForIndexedStateT
-
-    checkAll("IndexedStateT[ListWrapper, String, Int, Int]", ArrowTests[IndexedStateT[ListWrapper, ?, ?, Int]].arrow[String, String, String, Int, Int, Int])
-    checkAll("Arrow[IndexedStateT[ListWrapper, ?, ?, Int]]", SerializableTests.serializable(Arrow[IndexedStateT[ListWrapper, ?, ?, Int]]))
-
-    Arrow[IndexedStateT[ListWrapper, ?, ?, Int]]
-  }
-
   {
     // F has a Monad
     implicit val F = ListWrapper.monad