diff --git a/components/style/gecko/wrapper.rs b/components/style/gecko/wrapper.rs
index 621fef9b5fa..c5588ca4b97 100644
--- a/components/style/gecko/wrapper.rs
+++ b/components/style/gecko/wrapper.rs
@@ -438,8 +438,8 @@ impl<'a> Iterator for GeckoChildrenIterator<'a> {
                 *self = GeckoChildrenIterator::Current(next);
                 curr
             },
-            GeckoChildrenIterator::GeckoIterator(ref it) => unsafe {
-                Gecko_GetNextStyleChild(&it).map(GeckoNode)
+            GeckoChildrenIterator::GeckoIterator(ref mut it) => unsafe {
+                Gecko_GetNextStyleChild(it).map(GeckoNode)
             }
         }
     }
diff --git a/components/style/gecko_bindings/bindings.rs b/components/style/gecko_bindings/bindings.rs
index 4def95850e1..7c219fceeb3 100644
--- a/components/style/gecko_bindings/bindings.rs
+++ b/components/style/gecko_bindings/bindings.rs
@@ -242,7 +242,7 @@ extern "C" {
     pub fn Gecko_DropStyleChildrenIterator(it: StyleChildrenIteratorOwned);
 }
 extern "C" {
-    pub fn Gecko_GetNextStyleChild(it: StyleChildrenIteratorBorrowed)
+    pub fn Gecko_GetNextStyleChild(it: StyleChildrenIteratorBorrowedMut)
      -> RawGeckoNodeBorrowedOrNull;
 }
 extern "C" {