From e66f7a1b7d71739ab63d9d7a5ff8349224b117a8 Mon Sep 17 00:00:00 2001
From: Michael Zuber <michaelg.zuber@gmail.com>
Date: Wed, 2 Nov 2016 09:36:14 -0400
Subject: [PATCH 1/2] Added findValid method on Validated that accumulates
 errors. Closes #1447

---
 core/src/main/scala/cats/data/Validated.scala | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/core/src/main/scala/cats/data/Validated.scala b/core/src/main/scala/cats/data/Validated.scala
index d55915dab5..708f1156a0 100644
--- a/core/src/main/scala/cats/data/Validated.scala
+++ b/core/src/main/scala/cats/data/Validated.scala
@@ -44,6 +44,8 @@ sealed abstract class Validated[+E, +A] extends Product with Serializable {
 
   /**
    * Return this if it is Valid, or else fall back to the given default.
+   * The functionality is similar to that of [[findValid]] except for failure accumulation,
+   * where here only the error on the right is preserved and the error on the left is ignored.
    */
   def orElse[EE, AA >: A](default: => Validated[EE, AA]): Validated[EE, AA] =
     this match {
@@ -51,6 +53,18 @@ sealed abstract class Validated[+E, +A] extends Product with Serializable {
       case Invalid(_) => default
     }
 
+  /**
+    * If `this` is valid return `this`, otherwise if `that` is valid return `that`, otherwise combine the failures.
+    * This is similar to [[orElse]] except that here failures are accumulated.
+    */
+  def findValid[EE >: E, AA >: A](that: => Validated[EE, AA])(implicit EE: Semigroup[EE]): Validated[EE, AA] = this match {
+    case v @ Valid(_) => v
+    case Invalid(e) => that match {
+      case v @ Valid(_) => v
+      case Invalid(ee) => Invalid(EE.combine(e, ee))
+    }
+  }
+
   /**
    * Converts the value to an Either[E, A]
    */

From 31021548a12dfa902bba456ee3c25e71b0c2aff0 Mon Sep 17 00:00:00 2001
From: Michael Zuber <michaelg.zuber@gmail.com>
Date: Fri, 4 Nov 2016 10:52:25 -0400
Subject: [PATCH 2/2] Added tests for orElse and findValid on Validated

---
 .../scala/cats/tests/ValidatedTests.scala     | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/tests/src/test/scala/cats/tests/ValidatedTests.scala b/tests/src/test/scala/cats/tests/ValidatedTests.scala
index d40ee2cf6e..7904f7a860 100644
--- a/tests/src/test/scala/cats/tests/ValidatedTests.scala
+++ b/tests/src/test/scala/cats/tests/ValidatedTests.scala
@@ -114,6 +114,25 @@ class ValidatedTests extends CatsSuite {
     }
   }
 
+  test("findValid accumulates failures") {
+    forAll { (v: Validated[String, Int], u: Validated[String, Int]) =>
+      v findValid u shouldEqual { (v, u) match {
+        case (vv @ Valid(_), _) => vv
+        case (_, uu @ Valid(_)) => uu
+        case (Invalid(s1), Invalid(s2)) => Invalid(s1 ++ s2)
+      }}
+    }
+  }
+
+  test("orElse ignores left failure") {
+    forAll { (v: Validated[String, Int], u: Validated[String, Int]) =>
+      v orElse u shouldEqual { (v, u) match {
+        case (vv @ Valid(_), _) => vv
+        case (_, uu) => uu
+      }}
+    }
+  }
+
   test("valueOr consistent with swap then map then merge") {
     forAll { (v: Validated[String, Int], f: String => Int) =>
       v.valueOr(f) should === (v.swap.map(f).merge)