diff --git a/tip_003_popup_card/lib/hero_dialog_route.dart b/tip_003_popup_card/lib/hero_dialog_route.dart
index 057488f..ac47237 100644
--- a/tip_003_popup_card/lib/hero_dialog_route.dart
+++ b/tip_003_popup_card/lib/hero_dialog_route.dart
@@ -10,8 +10,8 @@ import 'package:flutter/material.dart';
 class HeroDialogRoute<T> extends PageRoute<T> {
   /// {@macro hero_dialog_route}
   HeroDialogRoute({
-    @required WidgetBuilder builder,
-    RouteSettings settings,
+    required WidgetBuilder builder,
+    RouteSettings? settings,
     bool fullscreenDialog = false,
   })  : _builder = builder,
         super(settings: settings, fullscreenDialog: fullscreenDialog);