[scala/scala#11017] Various Map.WithDefault classes expose the more specific WithDefault class as return type of concat method

Author: joshlemer

library/src/scala/collection/IterableOnce.scala

@@ -5,7 +5,6 @@ import scala.language.{higherKinds, implicitConversions}
 import scala.annotation.unchecked.uncheckedVariance
 import scala.math.{Numeric, Ordering}
 import scala.reflect.ClassTag
-import java.lang.{StringBuilder => JStringBuilder}
 import scala.collection.mutable.StringBuilder
 
 /**

library/src/scala/collection/immutable/Map.scala

@@ -153,6 +153,9 @@ object Map extends MapFactory[Map] {
 
     override def mapFactory: MapFactory[Map] = underlying.mapFactory
 
+    override def concat [V2 >: V](xs: collection.Iterable[(K, V2)]): WithDefault[K, V2] =
+      new WithDefault(underlying.concat(xs), defaultValue)
+
     def remove(key: K): WithDefault[K, V] = new WithDefault[K, V](underlying.remove(key), defaultValue)
 
     def updated[V1 >: V](key: K, value: V1): WithDefault[K, V1] =

library/src/scala/collection/immutable/SortedMap.scala

@@ -96,8 +96,10 @@ object SortedMap extends SortedMapFactory.Delegate[SortedMap](TreeMap) {
     override def updated[V1 >: V](key: K, value: V1): WithDefault[K, V1] =
       new WithDefault[K, V1](underlying.updated(key, value), defaultValue)
 
-    override def remove(key: K): WithDefault[K, V] =
-      new WithDefault[K, V](underlying.remove(key), defaultValue)
+    override def concat [V2 >: V](xs: collection.Iterable[(K, V2)]): WithDefault[K, V2] =
+      new WithDefault( underlying.concat(xs) , defaultValue)
+
+    override def remove(key: K): WithDefault[K, V] = new WithDefault[K, V](underlying.remove(key), defaultValue)
 
     override def empty: WithDefault[K, V] = new WithDefault[K, V](underlying.empty, defaultValue)
 

library/src/scala/collection/mutable/Map.scala

@@ -2,7 +2,6 @@ package scala
 package collection
 package mutable
 
-import scala.collection.MapFactory
 import scala.language.higherKinds
 
 /** Base type of mutable Maps */
@@ -187,6 +186,9 @@ object Map extends MapFactory.Delegate[Map](HashMap) {
 
     def addOne(elem: (K, V)): WithDefault.this.type = { underlying.addOne(elem); this }
 
+    override def concat[V2 >: V](suffix: collection.Iterable[(K, V2)]): WithDefault[K, V2] =
+      underlying.concat(suffix).withDefault(defaultValue)
+
     override def empty: WithDefault[K, V] = new WithDefault[K, V](underlying.empty, defaultValue)
 
     override protected def fromSpecificIterable(coll: scala.collection.Iterable[(K, V)]): WithDefault[K, V] =

library/src/scala/collection/mutable/SortedMap.scala

@@ -73,6 +73,9 @@ object SortedMap extends SortedMapFactory.Delegate[SortedMap](TreeMap) {
 
     override def empty: WithDefault[K, V] = new WithDefault[K, V](underlying.empty, defaultValue)
 
+    override def concat[V2 >: V](suffix: collection.Iterable[(K, V2)]): WithDefault[K, V2] =
+      underlying.concat(suffix).withDefault(defaultValue)
+
     override protected def fromSpecificIterable(coll: scala.collection.Iterable[(K, V)]): WithDefault[K, V] =
       new WithDefault[K, V](sortedMapFactory.from(coll), defaultValue)