Fix and test case for #2075.

5 files changed, 14 insertions, 7 deletions

diff --git a/src/library/scala/collection/SortedMapLike.scala b/src/library/scala/collection/SortedMapLike.scala
index 2e75053f9b..c7a8ebbd62 100644
--- a/src/library/scala/collection/SortedMapLike.scala
+++ b/src/library/scala/collection/SortedMapLike.scala
@@ -36,11 +36,9 @@ self =>
   override def keySet : SortedSet[A] = new DefaultKeySortedSet
 
   protected class DefaultKeySortedSet extends super.DefaultKeySet with SortedSet[A] {
-    def ordering = self.ordering;
-    /** We can't give an implementation of +/- here because we do not have a generic sorted set implementation
-     */
-    override def + (elem: A): SortedSet[A] = throw new UnsupportedOperationException("keySet.+")
-    override def - (elem: A): SortedSet[A] = throw new UnsupportedOperationException("keySet.-")
+    implicit def ordering = self.ordering
+    override def + (elem: A): SortedSet[A] = (SortedSet[A]() ++ this + elem)
+    override def - (elem: A): SortedSet[A] = (SortedSet[A]() ++ this - elem)
     override def rangeImpl(from : Option[A], until : Option[A]) : SortedSet[A] = {
       val map = self.rangeImpl(from, until)
       new map.DefaultKeySortedSet
diff --git a/src/library/scala/collection/SortedSet.scala b/src/library/scala/collection/SortedSet.scala
index a1213a9dc4..33e5551824 100644
--- a/src/library/scala/collection/SortedSet.scala
+++ b/src/library/scala/collection/SortedSet.scala
@@ -20,7 +20,7 @@ import generic._
  */
 trait SortedSet[A] extends Set[A] with SortedSetLike[A, SortedSet[A]] {
   /** Needs to be overridden in subclasses. */
-  override def empty: SortedSet[A] = throw new UnsupportedOperationException("SortedMap.empty")
+  override def empty: SortedSet[A] = SortedSet.empty[A]
 }
 
 /**
diff --git a/src/library/scala/collection/SortedSetLike.scala b/src/library/scala/collection/SortedSetLike.scala
index b0a2f20992..1c41ee3a5a 100644
--- a/src/library/scala/collection/SortedSetLike.scala
+++ b/src/library/scala/collection/SortedSetLike.scala
@@ -21,6 +21,8 @@ import generic._
 trait SortedSetLike[A, +This <: SortedSet[A] with SortedSetLike[A, This]] extends Sorted[A, This] with SetLike[A, This] {
 self =>
 
+  implicit def ordering: Ordering[A]
+
   override def keySet = repr
 
   override def firstKey: A = head
diff --git a/src/library/scala/collection/immutable/SortedSet.scala b/src/library/scala/collection/immutable/SortedSet.scala
index 0fd9365dd1..126b751164 100644
--- a/src/library/scala/collection/immutable/SortedSet.scala
+++ b/src/library/scala/collection/immutable/SortedSet.scala
@@ -24,7 +24,7 @@ import mutable.Builder
  */
 trait SortedSet[A] extends Set[A] with scala.collection.SortedSet[A] with SortedSetLike[A, SortedSet[A]] {
   /** Needs to be overridden in subclasses. */
-  override def empty: SortedSet[A] = throw new UnsupportedOperationException("SortedMap.empty")
+  override def empty: SortedSet[A] = SortedSet.empty[A]
 }
 
 /**
diff --git a/test/files/run/bug2075.scala b/test/files/run/bug2075.scala
new file mode 100644
index 0000000000..f328faddcb
--- /dev/null
+++ b/test/files/run/bug2075.scala
@@ -0,0 +1,7 @@
+object Test extends Application {
+  var tm = new scala.collection.immutable.TreeMap[Int,Int]
+  for (i <- 0 to 100)
+    tm = tm.insert(i, i)
+
+  tm.keySet.filter(_ < 40)
+}
\ No newline at end of file