From 3fe7949520429f2da0c6a74d0d650fb9925da22d Mon Sep 17 00:00:00 2001
From: Julien Richard-Foy <julien@richard-foy.fr>
Date: Mon, 12 Aug 2019 18:45:57 +0200
Subject: [PATCH] Add IterableOnce operations to IterableOnceOps

Fixes scala/bug#11675

This change is backward compatible, because nothing is removed.
It should also be forward compatible, because `IterableOnceOps[A]` had
`IterableOnce[A]` as a self-type on 2.13.0, meaning that code relying on the
newly introduced methods also worked on 2.13.0 because any `IterableOnceOps[A]`
instance was also effectively an `IterableOnce[A]`.
---
 build.sbt                                       | 4 ++--
 src/library/scala/collection/IterableOnce.scala | 3 ++-
 test/files/neg/abstract-report.check            | 2 +-
 test/files/neg/abstract-report2.check           | 2 +-
 4 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/build.sbt b/build.sbt
index f91291695c73..4d46a172f1a9 100644
--- a/build.sbt
+++ b/build.sbt
@@ -93,8 +93,8 @@ val mimaFilterSettings = Seq(
     ProblemFilters.exclude[DirectMissingMethodProblem]("scala.reflect.runtime.JavaMirrors#JavaMirror.typeTag"),
     ProblemFilters.exclude[MissingClassProblem]("scala.reflect.runtime.JavaMirrors$JavaMirror$typeTagCache$"),
     ProblemFilters.exclude[DirectMissingMethodProblem]("scala.reflect.api.TypeTags.TypeTagImpl"),
-    ProblemFilters.exclude[DirectMissingMethodProblem]("scala.reflect.api.Universe.TypeTagImpl"),
-  ),
+    ProblemFilters.exclude[DirectMissingMethodProblem]("scala.reflect.api.Universe.TypeTagImpl")
+  )
 )
 
 // Save MiMa logs
diff --git a/src/library/scala/collection/IterableOnce.scala b/src/library/scala/collection/IterableOnce.scala
index 6bb57c028b4d..c7773f0386a3 100644
--- a/src/library/scala/collection/IterableOnce.scala
+++ b/src/library/scala/collection/IterableOnce.scala
@@ -296,7 +296,8 @@ object IterableOnce {
   * @define coll collection
   *
   */
-trait IterableOnceOps[+A, +CC[_], +C] extends Any { this: IterableOnce[A] =>
+trait IterableOnceOps[+A, +CC[_], +C] extends Any with IterableOnce[A] {
+
   /////////////////////////////////////////////////////////////// Abstract methods that must be implemented
 
   /** Produces a $coll containing cumulative results of applying the
diff --git a/test/files/neg/abstract-report.check b/test/files/neg/abstract-report.check
index 21a70a329c06..2d36b72aec48 100644
--- a/test/files/neg/abstract-report.check
+++ b/test/files/neg/abstract-report.check
@@ -1,6 +1,6 @@
 abstract-report.scala:1: error: class Unimplemented needs to be abstract.
 Missing implementations for 6 members. Stub implementations follow:
-  // Members declared in scala.collection.IterableOnce
+  // Members declared in scala.collection.IterableOnceOps
   def iterator: Iterator[String] = ???
 
   // Members declared in scala.collection.IterableOps
diff --git a/test/files/neg/abstract-report2.check b/test/files/neg/abstract-report2.check
index b64d7d4eede7..87f7f1419f97 100644
--- a/test/files/neg/abstract-report2.check
+++ b/test/files/neg/abstract-report2.check
@@ -54,7 +54,7 @@ class Baz[T] extends Collection[T]
       ^
 abstract-report2.scala:15: error: class Dingus needs to be abstract.
 Missing implementations for 7 members. Stub implementations follow:
-  // Members declared in scala.collection.IterableOnce
+  // Members declared in scala.collection.IterableOnceOps
   def iterator: Iterator[(Set[Int], String)] = ???
 
   // Members declared in scala.collection.IterableOps