Fixed up the regression I slipped in with slice.

for pointing me toward the problem.  No review.

3 files changed, 24 insertions, 4 deletions

diff --git a/src/library/scala/collection/SeqViewLike.scala b/src/library/scala/collection/SeqViewLike.scala
index f5a61ec350..2bd8e29b65 100644
--- a/src/library/scala/collection/SeqViewLike.scala
+++ b/src/library/scala/collection/SeqViewLike.scala
@@ -194,7 +194,11 @@ trait SeqViewLike[+A,
     val thatElem = _thatElem
   } with ZippedAll[A1, B]
   protected def newReversed: Transformed[A] = new Reversed { }
-  protected def newPatched[B >: A](_from: Int, _patch: Seq[B], _replaced: Int): Transformed[B] = new { val from = _from; val patch = _patch; val replaced = _replaced } with Patched[B]
+  protected def newPatched[B >: A](_from: Int, _patch: Seq[B], _replaced: Int): Transformed[B] = new {
+    val from = _from
+    val patch = _patch
+    val replaced = _replaced
+  } with Patched[B]
   protected def newPrepended[B >: A](elem: B): Transformed[B] = new { protected[this] val fst = elem } with Prepended[B]
 
   override def reverse: This = newReversed.asInstanceOf[This]
diff --git a/src/library/scala/collection/generic/SliceInterval.scala b/src/library/scala/collection/generic/SliceInterval.scala
index 5c980c7677..56033ca8d8 100644
--- a/src/library/scala/collection/generic/SliceInterval.scala
+++ b/src/library/scala/collection/generic/SliceInterval.scala
@@ -11,12 +11,14 @@ package generic
 
 /** A container for the endpoints of a collection slice.
  *  The constructor is private to enforce the invariants:
- *  from >= 0 and until >= 0.
+ *  from >= 0, until >= 0, from <= until.
  */
 private[collection] class SliceInterval private (val from: Int, val until: Int) {
   // The width of this slice from end to end.  This is the
   // maximum size of the collection slice, but the collection
-  // need not have this many (or any) elements.
+  // need not have this many (or any) elements.  Since
+  // from <= until is a constructor invariant, we don't have to
+  // check for negative values.
   def width = until - from
 
   /** Returns a new SliceInterval with endpoints calculated in
@@ -41,5 +43,11 @@ private[collection] class SliceInterval private (val from: Int, val until: Int)
 }
 
 object SliceInterval {
-  def apply(from: Int, until: Int) = new SliceInterval(from max 0, until max 0)
+  def apply(from: Int, until: Int) = {
+    val lo = from max 0
+    val hi = until max 0
+
+    if (hi <= lo) new SliceInterval(lo, lo)
+    else new SliceInterval(lo, hi)
+  }
 }
diff --git a/test/files/run/patch-boundary.scala b/test/files/run/patch-boundary.scala
new file mode 100644
index 0000000000..ed1a0e9fc1
--- /dev/null
+++ b/test/files/run/patch-boundary.scala
@@ -0,0 +1,8 @@
+object Test {
+  def f = collection.mutable.ArrayBuffer(1, 2, 3, 4, 5, 6, 7, 8)
+  def g = f.patch(4, List(1, 2), 10)
+
+  def main(args: Array[String]): Unit = {
+    assert(g.size == 6)
+  }
+}