1 files changed, 3 insertions, 1 deletions
diff --git a/src/library/scala/collection/mutable/GrowingBuilder.scala b/src/library/scala/collection/mutable/GrowingBuilder.scala
index c4b5e546aa..27d554d98e 100644
--- a/src/library/scala/collection/mutable/GrowingBuilder.scala
+++ b/src/library/scala/collection/mutable/GrowingBuilder.scala
@@ -15,6 +15,8 @@ import generic._
 /** The canonical builder for collections that are growable, i.e. that support an
  *  efficient `+=` method which adds an element to the collection.
  *
+ *  GrowableBuilders can produce only a single instance of the collection they are growing.
+ *
  *  @author Paul Phillips
  *  @version 2.8
  *  @since 2.8
@@ -25,6 +27,6 @@ import generic._
 class GrowingBuilder[Elem, To <: Growable[Elem]](empty: To) extends Builder[Elem, To] {
   protected var elems: To = empty
   def +=(x: Elem): this.type = { elems += x; this }
-  def clear() { elems = empty }
+  def clear() { empty.clear }
   def result: To = elems
 }