From c910cea28083c18f27ed5e4256214c7315384c3e Mon Sep 17 00:00:00 2001
From: Maxim Davydov <maximdavydoff@yandex.ru>
Date: Mon, 18 Nov 2019 17:57:11 +0300
Subject: [PATCH] #3141 Changed .reduceMap signature

---
 core/src/main/scala/cats/Reducible.scala            |  4 ++--
 core/src/main/scala/cats/syntax/reducible.scala     |  4 ++--
 .../src/test/scala/cats/tests/ReducibleSuite.scala  | 13 +++++--------
 3 files changed, 9 insertions(+), 12 deletions(-)

diff --git a/core/src/main/scala/cats/Reducible.scala b/core/src/main/scala/cats/Reducible.scala
index 5872bf78e6..ba498bc633 100644
--- a/core/src/main/scala/cats/Reducible.scala
+++ b/core/src/main/scala/cats/Reducible.scala
@@ -97,8 +97,8 @@ import simulacrum.{noop, typeclass}
    *
    * `noop` usage description [[https://github.com/typelevel/simulacrum/issues/162 here]]
    */
-  @noop def reduceMapA[G[_], A, B](fga: F[G[A]])(f: A => B)(implicit G: Apply[G], B: Semigroup[B]): G[B] =
-    reduceLeftTo(fga)(ga => G.map(ga)(f))((gb, ga) => G.map2(gb, G.map(ga)(f))(B.combine))
+  @noop def reduceMapA[G[_], A, B](fa: F[A])(f: A => G[B])(implicit G: Apply[G], B: Semigroup[B]): G[B] =
+    reduceLeftTo(fa)(f)((gb, a) => G.map2(gb, f(a))(B.combine))
 
   /**
    * Monadic reducing by mapping the `A` values to `G[B]`. combining
diff --git a/core/src/main/scala/cats/syntax/reducible.scala b/core/src/main/scala/cats/syntax/reducible.scala
index 42cc8dda62..dd8f2b46f4 100644
--- a/core/src/main/scala/cats/syntax/reducible.scala
+++ b/core/src/main/scala/cats/syntax/reducible.scala
@@ -35,6 +35,6 @@ final class ReducibleOps0[F[_], A](private val fa: F[A]) extends AnyVal {
   def reduceA[G[_], B](implicit F: Reducible[F], ev: A <:< G[B], G: Apply[G], B: Semigroup[B]): G[B] =
     F.reduceA[G, B](fa.asInstanceOf[F[G[B]]])
 
-  def reduceMapA[G[_], B, C](f: B => C)(implicit F: Reducible[F], ev: A <:< G[B], G: Apply[G], C: Semigroup[C]): G[C] =
-    F.reduceMapA[G, B, C](fa.asInstanceOf[F[G[B]]])(f)
+  def reduceMapA[G[_], B](f: A => G[B])(implicit F: Reducible[F], G: Apply[G], C: Semigroup[B]): G[B] =
+    F.reduceMapA[G, A, B](fa)(f)
 }
diff --git a/tests/src/test/scala/cats/tests/ReducibleSuite.scala b/tests/src/test/scala/cats/tests/ReducibleSuite.scala
index f22e05334c..db786be42a 100644
--- a/tests/src/test/scala/cats/tests/ReducibleSuite.scala
+++ b/tests/src/test/scala/cats/tests/ReducibleSuite.scala
@@ -102,21 +102,18 @@ abstract class ReducibleSuite[F[_]: Reducible](name: String)(implicit ArbFInt: A
   }
 
   test(s"Reducible[$name].reduceMapA successful case") {
-    def intToString(i: Int): String = i.toString
-
     val expected = "123"
-    val actual =
-      rangeE(1.asRight[String], 2.asRight[String], 3.asRight[String]).reduceMapA(intToString)
+    val actual = range(1, 3).reduceMapA(_.toString.some)
 
-    actual should ===(expected.asRight[String])
+    actual should ===(expected.some)
   }
 
   test(s"Reducible[$name].reduceMapA failure case") {
-    def intToString(i: Int): String = i.toString
+    def intToString(i: Long): Either[String, Int] = if (i == 2) i.toInt.asRight else "boom!!!".asLeft
 
     val expected = "boom!!!"
-    val actual = rangeE(1.asRight, "boom!!!".asLeft, 3.asRight).reduceMapA(intToString)
-    actual should ===(expected.asLeft[String])
+    val actual = range(1, 3).reduceMapA(intToString)
+    actual should ===(expected.asLeft[Int])
   }
 
   test(s"Reducible[$name].toNonEmptyList/toList consistency") {