Some work towards fixing ticket #2030.

3 files changed, 27 insertions, 5 deletions

diff --git a/src/library/scala/collection/generic/ImmutableSortedSetFactory.scala b/src/library/scala/collection/generic/ImmutableSortedSetFactory.scala
new file mode 100644
index 0000000000..94284b505e
--- /dev/null
+++ b/src/library/scala/collection/generic/ImmutableSortedSetFactory.scala
@@ -0,0 +1,7 @@
+package scala.collection.generic
+
+/** A template for companion objects of mutable.Map and subclasses thereof.
+ */
+abstract class ImmutableSortedSetFactory[CC[A] <: immutable.SortedSet[A] with SortedSetTemplate[A, CC[A]]] extends SortedSetFactory[CC]{
+  def newBuilder[A](implicit ord: Ordering[A]): Builder[A, CC[A]] = new SetBuilder[A, CC[A]](empty)
+}
diff --git a/src/library/scala/collection/generic/SortedSetFactory.scala b/src/library/scala/collection/generic/SortedSetFactory.scala
new file mode 100644
index 0000000000..3fdcea64fb
--- /dev/null
+++ b/src/library/scala/collection/generic/SortedSetFactory.scala
@@ -0,0 +1,19 @@
+package scala.collection.generic
+
+/** A template for companion objects of Set and subclasses thereof.
+ */
+abstract class SortedSetFactory[CC[A] <: SortedSet[A] with SortedSetTemplate[A, CC[A]]] {
+  type Coll = CC[_]
+
+  def newBuilder[A](implicit ord: Ordering[A]): Builder[A, CC[A]]
+
+  def empty[A](implicit ord: Ordering[A]): CC[A]
+
+  def apply[A](elems: A*)(implicit ord: Ordering[A]): CC[A] = (newBuilder[A](ord) ++= elems).result
+
+  implicit def newBuilderFactory[A](implicit ord : Ordering[A]) : BuilderFactory[A, CC[A], Coll] = new SortedSetBuilderFactory()(ord);
+
+  class SortedSetBuilderFactory[A](implicit ord: Ordering[A]) extends BuilderFactory[A, CC[A], Coll] {
+    def apply(from: Coll) = newBuilder[A](ord)
+  }
+}
diff --git a/src/library/scala/collection/immutable/TreeSet.scala b/src/library/scala/collection/immutable/TreeSet.scala
index ddddf7bab0..36e4fc98c4 100644
--- a/src/library/scala/collection/immutable/TreeSet.scala
+++ b/src/library/scala/collection/immutable/TreeSet.scala
@@ -14,9 +14,8 @@ package scala.collection.immutable
 import generic._
 
 /** The canonical factory of <a href="TreeSet.html">TreeSet</a>'s. */
-object TreeSet {
+object TreeSet extends SortedSetFactory[TreeSet]{
 
-  type Coll = TreeSet[_]
   implicit def implicitBuilder[A](implicit ordering : Ordering[A]) : Builder[A, TreeSet[A]] = newBuilder[A](ordering)
   def newBuilder[A](implicit ordering : Ordering[A]) : Builder[A, TreeSet[A]] = new AddingBuilder(empty[A](ordering))
 
@@ -24,9 +23,6 @@ object TreeSet {
    */
   def empty[A](implicit ordering : Ordering[A]) = new TreeSet[A]
 
-  /** The canonical factory for this type
-   */
-  def apply[A](elems: A*)(implicit ordering : Ordering[A]) : TreeSet[A] = empty[A] ++ elems
 }
 
 /** This class implements immutable sets using a tree.