Imported Upstream version 1.3upstream/1.3

1 files changed, 5 insertions, 5 deletions

diff --git a/src/pkg/container/list/list.go b/src/pkg/container/list/list.go
index ed2d15a45..0256768ef 100644
--- a/src/pkg/container/list/list.go
+++ b/src/pkg/container/list/list.go
@@ -65,7 +65,7 @@ func New() *List { return new(List).Init() }
 // The complexity is O(1).
 func (l *List) Len() int { return l.len }
 
-// Front returns the first element of list l or nil
+// Front returns the first element of list l or nil.
 func (l *List) Front() *Element {
 	if l.len == 0 {
 		return nil
@@ -180,18 +180,18 @@ func (l *List) MoveToBack(e *Element) {
 }
 
 // MoveBefore moves element e to its new position before mark.
-// If e is not an element of l, or e == mark, the list is not modified.
+// If e or mark is not an element of l, or e == mark, the list is not modified.
 func (l *List) MoveBefore(e, mark *Element) {
-	if e.list != l || e == mark {
+	if e.list != l || e == mark || mark.list != l {
 		return
 	}
 	l.insert(l.remove(e), mark.prev)
 }
 
 // MoveAfter moves element e to its new position after mark.
-// If e is not an element of l, or e == mark, the list is not modified.
+// If e or mark is not an element of l, or e == mark, the list is not modified.
 func (l *List) MoveAfter(e, mark *Element) {
-	if e.list != l || e == mark {
+	if e.list != l || e == mark || mark.list != l {
 		return
 	}
 	l.insert(l.remove(e), mark)