Discovered ListMap.++ returns a Map instead of ...

Discovered ListMap.++ returns a Map instead of a ListMap. Does
preserving binary compatibility mean we can't fix this sort of thing?
Fixing for now, inquiring via: review by odersky.

2 files changed, 10 insertions, 3 deletions

diff --git a/src/library/scala/collection/immutable/ListMap.scala b/src/library/scala/collection/immutable/ListMap.scala
index 6721d5bbf0..6a166e365d 100644
--- a/src/library/scala/collection/immutable/ListMap.scala
+++ b/src/library/scala/collection/immutable/ListMap.scala
@@ -89,6 +89,14 @@ class ListMap[A, +B] extends Map[A, B] with MapLike[A, B, ListMap[A, B]] {
   override def + [B1 >: B] (elem1: (A, B1), elem2: (A, B1), elems: (A, B1) *): ListMap[A, B1] =
     this + elem1 + elem2 ++ elems
 
+  /** Adds a number of elements provided by a traversable object
+   *  and returns a new collection with the added elements.
+   *
+   *  @param xs     the traversable object.
+   */
+  override def ++[B1 >: B](xs: TraversableOnce[(A, B1)]): ListMap[A, B1] =
+    ((repr: ListMap[A, B1]) /: xs) (_ + _)
+
   /** This creates a new mapping without the given <code>key</code>.
    *  If the map does not contain a mapping for the given key, the
    *  method returns the same map.
diff --git a/src/library/scala/collection/immutable/SortedMap.scala b/src/library/scala/collection/immutable/SortedMap.scala
index 2f0749c37a..f49c4a9986 100644
--- a/src/library/scala/collection/immutable/SortedMap.scala
+++ b/src/library/scala/collection/immutable/SortedMap.scala
@@ -40,8 +40,7 @@ trait SortedMap[A, +B] extends Map[A, B]
   override def updated [B1 >: B](key: A, value: B1): SortedMap[A, B1] = this + ((key, value))
 
   /** Add a key/value pair to this map.
-   *  @param    key the key
-   *  @param    value the value
+   *  @param    kv the key/value pair
    *  @return   A new map with the new binding added to this map
    *  @note     needs to be overridden in subclasses
    */
@@ -60,7 +59,7 @@ trait SortedMap[A, +B] extends Map[A, B]
   /** Adds a number of elements provided by a traversable object
    *  and returns a new collection with the added elements.
    *
-   *  @param elems     the traversable object.
+   *  @param xs     the traversable object.
    */
   override def ++[B1 >: B](xs: TraversableOnce[(A, B1)]): SortedMap[A, B1] =
     ((repr: SortedMap[A, B1]) /: xs) (_ + _)