diff --git a/components/script/dom/promise.rs b/components/script/dom/promise.rs
index dd09b1df3a1..b8d30bd3651 100644
--- a/components/script/dom/promise.rs
+++ b/components/script/dom/promise.rs
@@ -317,7 +317,7 @@ unsafe extern "C" fn do_nothing_promise_executor(
     vp: *mut JSVal,
 ) -> bool {
     let args = CallArgs::from_vp(vp, argc);
-    *args.rval() = UndefinedValue();
+    args.rval().set(UndefinedValue());
     true
 }