diff --git a/components/script/dom/webidls/HTMLFieldSetElement.webidl b/components/script/dom/webidls/HTMLFieldSetElement.webidl
index 26f319ff108..1a009b523dd 100644
--- a/components/script/dom/webidls/HTMLFieldSetElement.webidl
+++ b/components/script/dom/webidls/HTMLFieldSetElement.webidl
@@ -11,13 +11,10 @@ interface HTMLFieldSetElement : HTMLElement {
 
   //readonly attribute DOMString type;
 
-  //HTMLFormControlsCollection: https://github.com/servo/servo/issues/8566
-  //readonly attribute HTMLFormControlsCollection elements;
-
-  readonly attribute HTMLCollection elements;
+  [SameObject] readonly attribute HTMLCollection elements;
 
   //readonly attribute boolean willValidate;
-  readonly attribute ValidityState validity;
+  [SameObject] readonly attribute ValidityState validity;
   //readonly attribute DOMString validationMessage;
   //boolean checkValidity();
   //boolean reportValidity();