1 files changed, 1 insertions, 1 deletions
diff --git a/src/library/scala/collection/IndexedSeqOptimized.scala b/src/library/scala/collection/IndexedSeqOptimized.scala
index ade04e4de8..42cb37aa24 100755
--- a/src/library/scala/collection/IndexedSeqOptimized.scala
+++ b/src/library/scala/collection/IndexedSeqOptimized.scala
@@ -206,7 +206,7 @@ trait IndexedSeqOptimized[+A, +Repr] extends Any with IndexedSeqLike[A, Repr] {
 
   override /*SeqLike*/
   def lastIndexWhere(p: A => Boolean, end: Int): Int = {
-    var i = end
+    var i = math.min(end, length - 1)
     while (i >= 0 && !p(this(i))) i -= 1
     i
   }