--- a/dom/bindings/BindingUtils.h
+++ b/dom/bindings/BindingUtils.h
@@ -3105,17 +3105,17 @@ class PinnedStringId
   operator const jsid& () const {
     return id;
   }
 
   operator JS::Handle<jsid> () const {
     /* This is safe because we have pinned the string. */
     return JS::Handle<jsid>::fromMarkedLocation(&id);
   }
-};
+} JS_HAZ_ROOTED;
 
 namespace binding_detail {
 /**
  * WebIDL getters have a "generic" JSNative that is responsible for the
  * following things:
  *
  * 1) Determining the "this" pointer for the C++ call.
  * 2) Extracting the "specialized" getter from the jitinfo on the JSFunction.