Fix SI-5986.

Here we had an issue that RedBlack does not work the same way
for sets - which are not supposed to replace an element if
it is the same (wrt equals) and maps - which should replace
the corresponding values.

Adding an overwrite parameter which decides whether to overwrite
added keys if they are the same in the ordering.

Fix tests.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/library/scala/collection/immutable/TreeMap.scala b/src/library/scala/collection/immutable/TreeMap.scala
index 4c1a5f2e03..51bc76efc3 100644
--- a/src/library/scala/collection/immutable/TreeMap.scala
+++ b/src/library/scala/collection/immutable/TreeMap.scala
@@ -131,7 +131,7 @@ class TreeMap[A, +B] private (tree: RB.Tree[A, B])(implicit val ordering: Orderi
    *  @param value   the value to be associated with `key`
    *  @return        a new $coll with the updated binding
    */
-  override def updated [B1 >: B](key: A, value: B1): TreeMap[A, B1] = new TreeMap(RB.update(tree, key, value))
+  override def updated [B1 >: B](key: A, value: B1): TreeMap[A, B1] = new TreeMap(RB.update(tree, key, value, true))
 
   /** Add a key/value pair to this map.
    *  @tparam   B1   type of the value of the new binding, a supertype of `B`
@@ -171,7 +171,7 @@ class TreeMap[A, +B] private (tree: RB.Tree[A, B])(implicit val ordering: Orderi
    */
   def insert [B1 >: B](key: A, value: B1): TreeMap[A, B1] = {
     assert(!RB.contains(tree, key))
-    new TreeMap(RB.update(tree, key, value))
+    new TreeMap(RB.update(tree, key, value, true))
   }
 
   def - (key:A): TreeMap[A, B] =