Changed abstract class RedBlack to singleton object.

3 files changed, 13 insertions, 10 deletions

diff --git a/src/library/scala/collection/immutable/RedBlack.scala b/src/library/scala/collection/immutable/RedBlack.scala
index 3fbe9a3407..4069c86c57 100644
--- a/src/library/scala/collection/immutable/RedBlack.scala
+++ b/src/library/scala/collection/immutable/RedBlack.scala
@@ -16,7 +16,7 @@ package immutable
  *  @since 2.3
  */
 @SerialVersionUID(8691885935445612921L)
-abstract class RedBlack extends Serializable {
+object RedBlack extends Serializable {
 
   private def blacken[A, B](t: Tree[A, B]): Tree[A, B] = t match {
     case RedTree(k, v, l, r) => BlackTree(k, v, l, r)
diff --git a/src/library/scala/collection/immutable/TreeMap.scala b/src/library/scala/collection/immutable/TreeMap.scala
index 3dfda05e17..a13e78086b 100644
--- a/src/library/scala/collection/immutable/TreeMap.scala
+++ b/src/library/scala/collection/immutable/TreeMap.scala
@@ -23,7 +23,7 @@ object TreeMap extends ImmutableSortedMapFactory[TreeMap] {
   def empty[A, B](implicit ord: Ordering[A]) = new TreeMap[A, B]()(ord)
   /** $sortedMapCanBuildFromInfo */
   implicit def canBuildFrom[A, B](implicit ord: Ordering[A]): CanBuildFrom[Coll, (A, B), TreeMap[A, B]] = new SortedMapCanBuildFrom[A, B]
-  private def make[A, B](s: Int, t: RedBlack#Tree[A, B])(implicit ord: Ordering[A]) = new TreeMap[A, B](s, t)(ord)
+  private def make[A, B](s: Int, t: RedBlack.Tree[A, B])(implicit ord: Ordering[A]) = new TreeMap[A, B](s, t)(ord)
 }
 
 /** This class implements immutable maps using a tree.
@@ -46,13 +46,14 @@ object TreeMap extends ImmutableSortedMapFactory[TreeMap] {
  *  @define mayNotTerminateInf
  *  @define willNotTerminateInf
  */
-class TreeMap[A, +B](override val size: Int, t: RedBlack#Tree[A, B])(implicit val ordering: Ordering[A])
-  extends RedBlack
-     with SortedMap[A, B]
+class TreeMap[A, +B](override val size: Int, t: RedBlack.Tree[A, B])(implicit val ordering: Ordering[A])
+  extends SortedMap[A, B]
      with SortedMapLike[A, B, TreeMap[A, B]]
      with MapLike[A, B, TreeMap[A, B]]
      with Serializable {
 
+  import RedBlack._
+
   def isSmaller(x: A, y: A) = ordering.lt(x, y)
 
   override protected[this] def newBuilder : Builder[(A, B), TreeMap[A, B]] =
@@ -60,7 +61,7 @@ class TreeMap[A, +B](override val size: Int, t: RedBlack#Tree[A, B])(implicit va
 
   def this()(implicit ordering: Ordering[A]) = this(0, null)(ordering)
 
-  protected val tree: RedBlack#Tree[A, B] = if (size == 0) Empty() else t
+  protected val tree: RedBlack.Tree[A, B] = if (size == 0) Empty() else t
 
   override def rangeImpl(from : Option[A], until : Option[A]): TreeMap[A,B] = {
     val ntree = tree.range(from,until)
diff --git a/src/library/scala/collection/immutable/TreeSet.scala b/src/library/scala/collection/immutable/TreeSet.scala
index 47a28f88df..8462ae5af3 100644
--- a/src/library/scala/collection/immutable/TreeSet.scala
+++ b/src/library/scala/collection/immutable/TreeSet.scala
@@ -47,9 +47,11 @@ object TreeSet extends ImmutableSortedSetFactory[TreeSet] {
  *  @define willNotTerminateInf
  */
 @SerialVersionUID(-234066569443569402L)
-class TreeSet[A](override val size: Int, t: RedBlack#Tree[A, Unit])
+class TreeSet[A](override val size: Int, t: RedBlack.Tree[A, Unit])
                 (implicit val ordering: Ordering[A])
-  extends RedBlack with SortedSet[A] with SortedSetLike[A, TreeSet[A]] with Serializable {
+  extends SortedSet[A] with SortedSetLike[A, TreeSet[A]] with Serializable {
+
+  import RedBlack._
 
   override def stringPrefix = "TreeSet"
 
@@ -101,9 +103,9 @@ class TreeSet[A](override val size: Int, t: RedBlack#Tree[A, Unit])
 
   def this()(implicit ordering: Ordering[A]) = this(0, null)(ordering)
 
-  protected val tree: RedBlack#Tree[A, Unit] = if (size == 0) Empty() else t
+  protected val tree: RedBlack.Tree[A, Unit] = if (size == 0) Empty() else t
 
-  private def newSet(s: Int, t: RedBlack#Tree[A, Unit]) = new TreeSet[A](s, t)
+  private def newSet(s: Int, t: RedBlack.Tree[A, Unit]) = new TreeSet[A](s, t)
 
   /** A factory to create empty sets of the same type of keys.
    */