RedBlack.scala: Change count from 'def' to 'val' in NonEmpty tree

to ensure TreeSet/TreeMap 'range' operations are O(log n) instead
of O(n).

1 files changed, 1 insertions, 1 deletions

diff --git a/src/library/scala/collection/immutable/RedBlack.scala b/src/library/scala/collection/immutable/RedBlack.scala
index 2d3d839851..534d476507 100644
--- a/src/library/scala/collection/immutable/RedBlack.scala
+++ b/src/library/scala/collection/immutable/RedBlack.scala
@@ -255,7 +255,7 @@ abstract class RedBlack[A] extends Serializable {
     }
     def first = if (left .isEmpty) key else left.first
     def last  = if (right.isEmpty) key else right.last
-    def count = 1 + left.count + right.count
+    val count = 1 + left.count + right.count
   }
   case object Empty extends Tree[Nothing] {
     def isEmpty = true