From 45ea5a304d789fd0e1ea99065c186407d784a021 Mon Sep 17 00:00:00 2001
From: "a.kozlov" <a.kozlov@dlg.im>
Date: Mon, 23 Nov 2020 01:38:18 +0300
Subject: [PATCH] wip

---
 .../main/scala/zio/prelude/Traversable.scala  | 33 ++++++++-----------
 .../scala/zio/prelude/TraversableSpec.scala   |  2 ++
 2 files changed, 15 insertions(+), 20 deletions(-)

diff --git a/core/shared/src/main/scala/zio/prelude/Traversable.scala b/core/shared/src/main/scala/zio/prelude/Traversable.scala
index 26099e967..1e6700fba 100644
--- a/core/shared/src/main/scala/zio/prelude/Traversable.scala
+++ b/core/shared/src/main/scala/zio/prelude/Traversable.scala
@@ -122,37 +122,30 @@ trait Traversable[F[+_]] extends Covariant[F] {
       }
     }
 
+
   /**
    * Compute each element of the collection
    * with specified effectual function `f`
    * and then reduces the results using the
    * `AssociativeEither[G].both` operation,
-   * returning effect with `None` if the collection is empty.
-   */
-  def forany[G[+_]: AssociativeEither: IdentityBoth: Covariant, A, B](fa: F[A])(f: A => G[B]): G[Option[B]] =
-    foldLeft(fa)(None: Option[G[B]]) {
-      case (Some(s), v) => Some(s.orElse(f(v)))
-      case (None, v)    => Some(f(v))
-    } match {
-      case Some(x) => x.map[Option[B]](Some(_))
-      case None    => IdentityBoth[G].any.as(None)
-    }
+   * returning `None` if the collection is empty.
+   */
+  def forany[G[+_]: AssociativeEither: Covariant, A, B](fa: F[A])(f: A => G[B]): Option[G[B]] = {
+    implicit val associative: Associative[G[B]] = Associative.make[G[B]](_ orElse _)
+    reduceMapOption(fa)(f)
+  }
 
   /**
    * Compute each element of the collection
    * with specified effectual function `f`
    * and then reduces the results using the
    * `CommutativeEither[G].both` operation,
-   * returning effect with `None` if the collection is empty.
-   */
-  def foranyPar[G[+_]: CommutativeEither: IdentityBoth: Covariant, A, B](fa: F[A])(f: A => G[B]): G[Option[B]] =
-    foldLeft(fa)(None: Option[G[B]]) {
-      case (Some(s), v) => Some(s.orElsePar(f(v)))
-      case (None, v)    => Some(f(v))
-    } match {
-      case Some(x) => x.map[Option[B]](Some(_))
-      case None    => IdentityBoth[G].any.as(None)
-    }
+   * returning `None` if the collection is empty.
+   */
+  def foranyPar[G[+_]: CommutativeEither: Covariant, A, B](fa: F[A])(f: A => G[B]): Option[G[B]] = {
+    implicit val associative: Associative[G[B]] = Associative.make[G[B]](_ orElsePar  _)
+    reduceMapOption(fa)(f)
+  }
 
   /**
    * Returns whether the collection is empty.
diff --git a/core/shared/src/test/scala/zio/prelude/TraversableSpec.scala b/core/shared/src/test/scala/zio/prelude/TraversableSpec.scala
index 25eabae98..66bd0fe39 100644
--- a/core/shared/src/test/scala/zio/prelude/TraversableSpec.scala
+++ b/core/shared/src/test/scala/zio/prelude/TraversableSpec.scala
@@ -141,6 +141,7 @@ object TraversableSpec extends DefaultRunnableSpec {
                                                   case Some(x) => IO.succeedNow(x)
                                                   case None    => IO.fail(())
                                                 }(Invariant.Function1Covariant))
+                                                .flip
                                                 .option
               expected: Option[Option[Int]] = {
                 val allResults = as.map(f)
@@ -160,6 +161,7 @@ object TraversableSpec extends DefaultRunnableSpec {
                                                case Some(x) => IO.succeedNow(x)
                                                case None    => IO.fail(())
                                              }(Invariant.Function1Covariant))
+                                             .flip
                                              .option
               expected: Option[Set[Int]] = {
                 val allResults = as.map(f)