exceptions

1 files changed, 3 insertions, 1 deletions

diff --git a/src/library/scala/collection/mutable/ObservableMap.scala b/src/library/scala/collection/mutable/ObservableMap.scala
index da08fb95d7..f6713125d9 100644
--- a/src/library/scala/collection/mutable/ObservableMap.scala
+++ b/src/library/scala/collection/mutable/ObservableMap.scala
@@ -50,6 +50,8 @@ trait ObservableMap[A, B, This <: ObservableMap[A, B, This]] requires This
 
   abstract override def clear: Unit = {
     super.clear
-    publish(new Reset with Undoable { def undo: Unit = error("cannot undo") })
+    publish(new Reset with Undoable {
+      def undo: Unit = throw new UnsupportedOperationException("cannot undo")
+    })
   }
 }