1 files changed, 4 insertions, 3 deletions
diff --git a/components/script/dom/customelementregistry.rs b/components/script/dom/customelementregistry.rs
index 4080731a534..abefc4eca58 100644
--- a/components/script/dom/customelementregistry.rs
+++ b/components/script/dom/customelementregistry.rs
@@ -399,20 +399,21 @@ impl CustomElementRegistryMethods for CustomElementRegistry {
     }
 
     /// <https://html.spec.whatwg.org/multipage/#dom-customelementregistry-whendefined>
+    #[allow(unsafe_code)]
     fn WhenDefined(&self, name: DOMString) -> Rc<Promise> {
         let global_scope = self.window.upcast::<GlobalScope>();
         let name = LocalName::from(&*name);
 
         // Step 1
         if !is_valid_custom_element_name(&name) {
-            let promise = Promise::new(global_scope);
+            let promise = unsafe { Promise::new_in_current_compartment(global_scope) };
             promise.reject_native(&DOMException::new(global_scope, DOMErrorName::SyntaxError));
             return promise;
         }
 
         // Step 2
         if self.definitions.borrow().contains_key(&name) {
-            let promise = Promise::new(global_scope);
+            let promise = unsafe { Promise::new_in_current_compartment(global_scope) };
             promise.resolve_native(&UndefinedValue());
             return promise;
         }
@@ -422,7 +423,7 @@ impl CustomElementRegistryMethods for CustomElementRegistry {
 
         // Steps 4, 5
         let promise = map.get(&name).cloned().unwrap_or_else(|| {
-            let promise = Promise::new(global_scope);
+            let promise = unsafe { Promise::new_in_current_compartment(global_scope) };
             map.insert(name, promise.clone());
             promise
         });