Modified SI-6150 fix again.

Have to keep a sharp eye on those ReusableCBFs.
Now all the indexed sequences should be using the
same instance.

2 files changed, 23 insertions, 4 deletions

diff --git a/src/library/scala/collection/generic/GenTraversableFactory.scala b/src/library/scala/collection/generic/GenTraversableFactory.scala
index 076f555506..6614dbdc62 100644
--- a/src/library/scala/collection/generic/GenTraversableFactory.scala
+++ b/src/library/scala/collection/generic/GenTraversableFactory.scala
@@ -38,11 +38,10 @@ import language.higherKinds
 abstract class GenTraversableFactory[CC[X] <: GenTraversable[X] with GenericTraversableTemplate[X, CC]]
   extends GenericCompanion[CC] {
 
-  // A default implementation of GenericCanBuildFrom which can be cast
-  // to whatever is desired.
-  val ReusableCBF: GenericCanBuildFrom[Nothing] = new GenericCanBuildFrom[Nothing] {
+  private[this] val ReusableCBFInstance: GenericCanBuildFrom[Nothing] = new GenericCanBuildFrom[Nothing] {
     override def apply() = newBuilder[Nothing]
   }
+  def ReusableCBF: GenericCanBuildFrom[Nothing] = ReusableCBFInstance
 
   /** A generic implementation of the `CanBuildFrom` trait, which forwards
    *  all calls to `apply(from)` to the `genericBuilder` method of
@@ -250,4 +249,3 @@ abstract class GenTraversableFactory[CC[X] <: GenTraversable[X] with GenericTrav
     b.result
   }
 }
-
diff --git a/src/library/scala/collection/generic/IndexedSeqFactory.scala b/src/library/scala/collection/generic/IndexedSeqFactory.scala
new file mode 100644
index 0000000000..e5162c640b
--- /dev/null
+++ b/src/library/scala/collection/generic/IndexedSeqFactory.scala
@@ -0,0 +1,21 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___     Scala API                            **
+**    / __/ __// _ | / /  / _ |    (c) 2003-2011, LAMP/EPFL             **
+**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
+** /____/\___/_/ |_/____/_/ | |                                         **
+**                          |/                                          **
+\*                                                                      */
+
+package scala.collection
+package generic
+
+import language.higherKinds
+
+/** A template for companion objects of IndexedSeq and subclasses thereof.
+ *
+ *  @since 2.8
+ */
+abstract class IndexedSeqFactory[CC[X] <: IndexedSeq[X] with GenericTraversableTemplate[X, CC]] extends SeqFactory[CC] {
+  override def ReusableCBF: GenericCanBuildFrom[Nothing] =
+    scala.collection.IndexedSeq.ReusableCBF.asInstanceOf[GenericCanBuildFrom[Nothing]]
+}