diff --git a/components/script/dom/attr.rs b/components/script/dom/attr.rs
index 028a91ea422..9a062679a4f 100644
--- a/components/script/dom/attr.rs
+++ b/components/script/dom/attr.rs
@@ -8,6 +8,7 @@ use dom::bindings::codegen::Bindings::AttrBinding::AttrMethods;
 use dom::bindings::codegen::InheritTypes::NodeCast;
 use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, JSRef, Temporary};
+use dom::bindings::js::{OptionalRootedRootable, RootedReference};
 use dom::bindings::utils::{Reflector, reflect_dom_object};
 use dom::element::{Element, AttributeHandlers};
 use dom::node::Node;
@@ -207,7 +208,7 @@ pub trait AttrHelpers<'a> {
 
 impl<'a> AttrHelpers<'a> for JSRef<'a, Attr> {
     fn set_value(self, set_type: AttrSettingType, value: AttrValue, owner: JSRef<Element>) {
-        assert!(Some(owner) == self.owner.map(|o| *o.root()));
+        assert!(Some(owner) == self.owner.root().r());
 
         let node: JSRef<Node> = NodeCast::from_ref(owner);
         let namespace_is_null = self.namespace == ns!("");