Iterators created with duplicate compare equal ...

Iterators created with duplicate compare equal if they are positioned at
the same element. Review by community.

1 files changed, 10 insertions, 1 deletions

diff --git a/src/library/scala/collection/Iterator.scala b/src/library/scala/collection/Iterator.scala
index de0ec5275f..32525d59a6 100644
--- a/src/library/scala/collection/Iterator.scala
+++ b/src/library/scala/collection/Iterator.scala
@@ -994,7 +994,8 @@ trait Iterator[+A] { self =>
   }
 
   /** Creates two new iterators that both iterate over the same elements
-   *  as this iterator (in the same order).
+   *  as this iterator (in the same order).  The duplicate iterators are
+   *  considered equal if they are positioned at the same element.
    *
    *  @return a pair of iterators
    */
@@ -1013,6 +1014,14 @@ trait Iterator[+A] { self =>
           e
         } else gap.dequeue
       }
+      // to verify partnerhood we use reference equality on gap because
+      // type testing does not discriminate based on origin.
+      private def compareGap(queue: scala.collection.mutable.Queue[A]) = gap eq queue
+      override def hashCode = gap.hashCode
+      override def equals(other: Any) = other match {
+        case x: Partner   => x.compareGap(gap) && gap.isEmpty
+        case _            => super.equals(other)
+      }
     }
     (new Partner, new Partner)
   }