Add enqueueAll to immutable.Queue

compat/src/main/scala-2.11/scala/collection/compat/package.scala

@@ -13,6 +13,7 @@
 package scala.collection
 
 import scala.collection.generic.{CanBuildFrom, GenericOrderedCompanion, IsTraversableLike}
+import scala.collection.{immutable => i}
 import scala.{collection => c}
 
 package object compat extends compat.PackageShared {
@@ -39,4 +40,8 @@ package object compat extends compat.PackageShared {
 
   implicit def toSeqExtensionMethods[A](self: c.Seq[A]): SeqExtensionMethods[A] =
     new SeqExtensionMethods[A](self)
+
+  implicit def toImmutableQueueExtensionMethods[A](
+      self: i.Queue[A]): ImmutableQueueExtensionMethods[A] =
+    new ImmutableQueueExtensionMethods[A](self)
 }

compat/src/main/scala-2.11_2.12/scala/collection/compat/PackageShared.scala

@@ -366,3 +366,8 @@ class MapViewExtensionMethods[K, V, C <: scala.collection.Map[K, V]](
   def filterKeys(p: K => Boolean): IterableView[(K, V), C] =
     self.filter { case (k, _) => p(k) }
 }
+
+class ImmutableQueueExtensionMethods[A](private val self: i.Queue[A]) extends AnyVal {
+  def enqueueAll[B >: A](iter: c.Iterable[B]): i.Queue[B] =
+    self.enqueue(iter.to[i.Iterable])
+}

compat/src/main/scala-2.12/scala/collection/compat/package.scala

@@ -14,7 +14,7 @@ package scala.collection
 
 import scala.collection.generic.{CanBuildFrom, GenericOrderedCompanion, IsTraversableLike}
 import scala.{collection => c}
-import scala.collection.{mutable => m}
+import scala.collection.{immutable => i, mutable => m}
 
 package object compat extends compat.PackageShared {
   implicit class MutableTreeMapExtensions2(private val fact: m.TreeMap.type) extends AnyVal {
@@ -50,4 +50,8 @@ package object compat extends compat.PackageShared {
 
   implicit def toSeqExtensionMethods[A](self: c.Seq[A]): SeqExtensionMethods[A] =
     new SeqExtensionMethods[A](self)
+
+  implicit def toImmutableQueueExtensionMethods[A](
+      self: i.Queue[A]): ImmutableQueueExtensionMethods[A] =
+    new ImmutableQueueExtensionMethods[A](self)
 }

compat/src/test/scala/test/scala/collection/ImmutableQueueTest.scala

@@ -0,0 +1,30 @@
+/*
+ * Scala (https://www.scala-lang.org)
+ *
+ * Copyright EPFL and Lightbend, Inc.
+ *
+ * Licensed under Apache License 2.0
+ * (http://www.apache.org/licenses/LICENSE-2.0).
+ *
+ * See the NOTICE file distributed with this work for
+ * additional information regarding copyright ownership.
+ */
+
+package test.scala.collection
+
+import org.junit.Assert._
+import org.junit.Test
+
+import scala.collection.compat._
+import scala.collection.immutable.Queue
+
+class ImmutableQueueTest {
+
+  @Test
+  def testEnqueueAll: Unit = {
+    val q                = Queue(1, 2)
+    val i: Iterable[Int] = List(3, 4)
+    val eq               = q.enqueueAll(i)
+    assertEquals(Queue(1, 2, 3, 4), eq)
+  }
+}