SI-6632 ListBuffer's updated accepts negative positions

Changed the behavior in SeqLike.updated (which would silently accept negatives and throw on empty.tail) to throw IndexOutOfBoundException.

Updated tests to verify the behavior in ListBuffer.  Everything else SeqLike will come along for the ride.

1 files changed, 4 insertions, 1 deletions

diff --git a/src/library/scala/collection/SeqLike.scala b/src/library/scala/collection/SeqLike.scala
index 960c277f67..fdfb1f2efc 100644
--- a/src/library/scala/collection/SeqLike.scala
+++ b/src/library/scala/collection/SeqLike.scala
@@ -509,11 +509,14 @@ trait SeqLike[+A, +Repr] extends Any with IterableLike[A, Repr] with GenSeqLike[
   }
 
   def updated[B >: A, That](index: Int, elem: B)(implicit bf: CanBuildFrom[Repr, B, That]): That = {
+    if (index < 0) throw new IndexOutOfBoundsException(index.toString)
     val b = bf(repr)
     val (prefix, rest) = this.splitAt(index)
+    val restColl = toCollection(rest)
+    if (restColl.isEmpty) throw new IndexOutOfBoundsException(index.toString)
     b ++= toCollection(prefix)
     b += elem
-    b ++= toCollection(rest).view.tail
+    b ++= restColl.view.tail
     b.result()
   }