diff --git a/js/xpconnect/src/xpcprivate.h b/js/xpconnect/src/xpcprivate.h
index 97f5c36fe8..5a32cd13f8 100644
--- a/js/xpconnect/src/xpcprivate.h
+++ b/js/xpconnect/src/xpcprivate.h
@@ -3111,7 +3111,7 @@ nsresult
 GetSandboxMetadata(JSContext* cx, JS::HandleObject sandboxArg,
                    JS::MutableHandleValue rval);
 
-[[nodiscard]] nsresult
+MOZ_MUST_USE nsresult
 SetSandboxMetadata(JSContext* cx, JS::HandleObject sandboxArg,
                    JS::HandleValue metadata);