Add mutable tree sets to the standard library.

This implementation is based on AVL trees.
The current implementation is contributed by Lucien Pereira.

Fixes #4147.

2 files changed, 10 insertions, 1 deletions

diff --git a/test/files/jvm/serialization.check b/test/files/jvm/serialization.check
index 15708f0c3b..bc56387f81 100644
--- a/test/files/jvm/serialization.check
+++ b/test/files/jvm/serialization.check
@@ -188,6 +188,10 @@ x = WrappedArray(1, 2, 3)
 y = WrappedArray(1, 2, 3)
 x equals y: true, y equals x: true
 
+x = TreeSet(1, 2, 3)
+y = TreeSet(1, 2, 3)
+x equals y: true, y equals x: true
+
 x =  xml:src="hello"
 y =  xml:src="hello"
 x equals y: true, y equals x: true
diff --git a/test/files/jvm/serialization.scala b/test/files/jvm/serialization.scala
index 9391b60e46..73bed2d46b 100644
--- a/test/files/jvm/serialization.scala
+++ b/test/files/jvm/serialization.scala
@@ -286,7 +286,7 @@ object Test3_mutable {
   import scala.collection.mutable.{
     ArrayBuffer, ArrayBuilder, ArraySeq, ArrayStack, BitSet, DoubleLinkedList,
     HashMap, HashSet, History, LinkedList, ListBuffer, Publisher, Queue,
-    Stack, StringBuilder, WrappedArray}
+    Stack, StringBuilder, WrappedArray, TreeSet}
 
   // in alphabetic order
   try {
@@ -380,6 +380,11 @@ object Test3_mutable {
     val wa1 = WrappedArray.make(Array(1, 2, 3))
     val _wa1: WrappedArray[Int] = read(write(wa1))
     check(wa1, _wa1)
+    
+    // TreeSet
+    val ts1 = TreeSet[Int]() ++= Array(1, 2, 3)
+    val _ts1: TreeSet[Int] = read(write(ts1))
+    check(ts1, _ts1)
   }
   catch {
     case e: Exception =>