Fix nullability for some routing related stuff (#67675)

packages/flutter/lib/src/rendering/layer.dart

@@ -2225,7 +2225,7 @@ class FollowerLayer extends ContainerLayer {
   Matrix4? _invertedTransform;
   bool _inverseDirty = true;
 
-  Offset? _transformOffset<S extends Object>(Offset localPosition) {
+  Offset? _transformOffset(Offset localPosition) {
     if (_inverseDirty) {
       _invertedTransform = Matrix4.tryInvert(getLastTransform()!);
       _inverseDirty = false;
@@ -2245,7 +2245,7 @@ class FollowerLayer extends ContainerLayer {
       }
       return false;
     }
-    final Offset? transformedOffset = _transformOffset<S>(localPosition);
+    final Offset? transformedOffset = _transformOffset(localPosition);
     if (transformedOffset == null) {
       return false;
     }

packages/flutter/lib/src/services/raw_keyboard.dart

@@ -2,7 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-
 import 'dart:io';
 import 'dart:ui';
 
@@ -737,7 +736,7 @@ class RawKeyboard {
 }
 
 @immutable
-class _ModifierSidePair extends Object {
+class _ModifierSidePair {
   const _ModifierSidePair(this.modifier, this.side);
 
   final ModifierKey modifier;

packages/flutter/lib/src/widgets/drag_target.dart

@@ -131,7 +131,6 @@ class Draggable<T extends Object> extends StatefulWidget {
        assert(maxSimultaneousDrags == null || maxSimultaneousDrags >= 0),
        super(key: key);
 
-
   /// The data that will be dropped by this draggable.
   final T? data;
 

packages/flutter/lib/src/widgets/routes.dart

@@ -881,7 +881,7 @@ abstract class ModalRoute<T> extends TransitionRoute<T> with LocalHistoryRoute<T
   /// The given [BuildContext] will be rebuilt if the state of the route changes
   /// while it is visible (specifically, if [isCurrent] or [canPop] change value).
   @optionalTypeArgs
-  static ModalRoute<T>? of<T extends Object>(BuildContext context) {
+  static ModalRoute<T>? of<T extends Object?>(BuildContext context) {
     final _ModalScopeStatus? widget = context.dependOnInheritedWidgetOfExactType<_ModalScopeStatus>();
     return widget?.route as ModalRoute<T>?;
   }
@@ -1818,7 +1818,7 @@ class _DialogRoute<T> extends PopupRoute<T> {
 ///
 ///  * [showDialog], which displays a Material-style dialog.
 ///  * [showCupertinoDialog], which displays an iOS-style dialog.
-Future<T> showGeneralDialog<T extends Object>({
+Future<T> showGeneralDialog<T extends Object?>({
   required BuildContext context,
   required RoutePageBuilder pageBuilder,
   bool barrierDismissible = false,

packages/flutter/test/widgets/routes_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'dart:collection';
 
 import 'package:flutter/foundation.dart';
@@ -19,7 +17,7 @@ final List<String> results = <String>[];
 
 Set<TestRoute> routes = HashSet<TestRoute>();
 
-class TestRoute extends Route<String> with LocalHistoryRoute<String> {
+class TestRoute extends Route<String?> with LocalHistoryRoute<String?> {
   TestRoute(this.name);
   final String name;
 
@@ -57,7 +55,7 @@ class TestRoute extends Route<String> with LocalHistoryRoute<String> {
   }
 
   @override
-  void didReplace(Route<dynamic> oldRoute) {
+  void didReplace(Route<dynamic>? oldRoute) {
     expect(oldRoute, isA<TestRoute>());
     final TestRoute castRoute = oldRoute as TestRoute;
     log('didReplace ${castRoute.name}');
@@ -65,11 +63,11 @@ class TestRoute extends Route<String> with LocalHistoryRoute<String> {
   }
 
   @override
-  bool didPop(String result) {
+  bool didPop(String? result) {
     log('didPop $result');
     bool returnValue;
     if (returnValue = super.didPop(result))
-      navigator.finalizeRoute(this);
+      navigator!.finalizeRoute(this);
     return returnValue;
   }
 
@@ -82,9 +80,9 @@ class TestRoute extends Route<String> with LocalHistoryRoute<String> {
   }
 
   @override
-  void didChangeNext(Route<dynamic> nextRoute) {
+  void didChangeNext(Route<dynamic>? nextRoute) {
     expect(nextRoute, anyOf(isNull, isA<TestRoute>()));
-    final TestRoute castRoute = nextRoute as TestRoute;
+    final TestRoute? castRoute = nextRoute as TestRoute?;
     log('didChangeNext ${castRoute?.name}');
     super.didChangeNext(castRoute);
   }
@@ -148,7 +146,7 @@ void main() {
         ),
       ),
     );
-    final NavigatorState host = navigatorKey.currentState;
+    final NavigatorState host = navigatorKey.currentState!;
     await runNavigatorTest(
       tester,
       host,
@@ -159,7 +157,7 @@ void main() {
         'initial: didChangeNext null',
       ],
     );
-    TestRoute second;
+    late TestRoute second;
     await runNavigatorTest(
       tester,
       host,
@@ -231,7 +229,7 @@ void main() {
         ),
       ),
     );
-    final NavigatorState host = navigatorKey.currentState;
+    final NavigatorState host = navigatorKey.currentState!;
     await runNavigatorTest(
       tester,
       host,
@@ -242,7 +240,7 @@ void main() {
         'first: didChangeNext null',
       ],
     );
-    TestRoute second;
+    late TestRoute second;
     await runNavigatorTest(
       tester,
       host,
@@ -294,7 +292,7 @@ void main() {
         'second: didChangeNext three',
       ],
     );
-    TestRoute four;
+    late TestRoute four;
     await runNavigatorTest(
       tester,
       host,
@@ -342,7 +340,7 @@ void main() {
         ),
       ),
     );
-    final NavigatorState host = navigatorKey.currentState;
+    final NavigatorState host = navigatorKey.currentState!;
     await runNavigatorTest(
       tester,
       host,
@@ -364,7 +362,7 @@ void main() {
         'A: didChangeNext B',
       ],
     );
-    TestRoute routeC;
+    late TestRoute routeC;
     await runNavigatorTest(
       tester,
       host,
@@ -377,7 +375,7 @@ void main() {
       ],
     );
     expect(routeC.isActive, isTrue);
-    TestRoute routeB;
+    late TestRoute routeB;
     await runNavigatorTest(
       tester,
       host,
@@ -424,7 +422,7 @@ void main() {
         ),
       ),
     );
-    final NavigatorState host = navigatorKey.currentState;
+    final NavigatorState host = navigatorKey.currentState!;
     await runNavigatorTest(
       tester,
       host,
@@ -552,7 +550,7 @@ void main() {
               builder: (BuildContext context) {
                 return ElevatedButton(
                   onPressed: () {
-                    Navigator.of(context).push<void>(
+                    Navigator.of(context)!.push<void>(
                       PageRouteBuilder<void>(
                         settings: settings,
                         pageBuilder: (BuildContext context, Animation<double> input, Animation<double> out) {
@@ -601,7 +599,7 @@ void main() {
             builder: (BuildContext context) {
               return ElevatedButton(
                 onPressed: () {
-                  Navigator.of(context).push<void>(
+                  Navigator.of(context)!.push<void>(
                     PageRouteBuilder<void>(
                       settings: settings,
                       pageBuilder: (BuildContext context, Animation<double> input, Animation<double> out) {
@@ -656,9 +654,9 @@ void main() {
       );
 
       // Push page one, its secondary animation is kAlwaysDismissedAnimation.
-      ProxyAnimation secondaryAnimationProxyPageOne;
-      ProxyAnimation animationPageOne;
-      navigator.currentState.push(
+      late ProxyAnimation secondaryAnimationProxyPageOne;
+      late ProxyAnimation animationPageOne;
+      navigator.currentState!.push(
         PageRouteBuilder<void>(
           pageBuilder: (_, Animation<double> animation, Animation<double> secondaryAnimation) {
             secondaryAnimationProxyPageOne = secondaryAnimation as ProxyAnimation;
@@ -675,9 +673,9 @@ void main() {
 
       // Push page two, the secondary animation of page one is the primary
       // animation of page two.
-      ProxyAnimation secondaryAnimationProxyPageTwo;
-      ProxyAnimation animationPageTwo;
-      navigator.currentState.push(
+      late ProxyAnimation secondaryAnimationProxyPageTwo;
+      late ProxyAnimation animationPageTwo;
+      navigator.currentState!.push(
         PageRouteBuilder<void>(
           pageBuilder: (_, Animation<double> animation, Animation<double> secondaryAnimation) {
             secondaryAnimationProxyPageTwo = secondaryAnimation as ProxyAnimation;
@@ -695,7 +693,7 @@ void main() {
 
       // Pop page two, the secondary animation of page one becomes
       // kAlwaysDismissedAnimation.
-      navigator.currentState.pop();
+      navigator.currentState!.pop();
       await tester.pump();
       await tester.pump(const Duration(milliseconds: 100));
       expect(secondaryAnimationPageOne.parent, animationPageTwo.parent);
@@ -714,9 +712,9 @@ void main() {
       );
 
       // Push page one, its secondary animation is kAlwaysDismissedAnimation.
-      ProxyAnimation secondaryAnimationProxyPageOne;
-      ProxyAnimation animationPageOne;
-      navigator.currentState.push(
+      late ProxyAnimation secondaryAnimationProxyPageOne;
+      late ProxyAnimation animationPageOne;
+      navigator.currentState!.push(
         PageRouteBuilder<void>(
           pageBuilder: (_, Animation<double> animation, Animation<double> secondaryAnimation) {
             secondaryAnimationProxyPageOne = secondaryAnimation as ProxyAnimation;
@@ -733,10 +731,10 @@ void main() {
 
       // Push page two, the secondary animation of page one is the primary
       // animation of page two.
-      ProxyAnimation secondaryAnimationProxyPageTwo;
-      ProxyAnimation animationPageTwo;
+      late ProxyAnimation secondaryAnimationProxyPageTwo;
+      late ProxyAnimation animationPageTwo;
       Route<void> secondRoute;
-      navigator.currentState.push(
+      navigator.currentState!.push(
         secondRoute = PageRouteBuilder<void>(
           pageBuilder: (_, Animation<double> animation, Animation<double> secondaryAnimation) {
             secondaryAnimationProxyPageTwo = secondaryAnimation as ProxyAnimation;
@@ -754,7 +752,7 @@ void main() {
 
       // Remove the second route, the secondary animation of page one is
       // kAlwaysDismissedAnimation again.
-      navigator.currentState.removeRoute(secondRoute);
+      navigator.currentState!.removeRoute(secondRoute);
       await tester.pump();
       expect(secondaryAnimationPageOne.parent, kAlwaysDismissedAnimation);
     });
@@ -769,9 +767,9 @@ void main() {
       );
 
       // Push page one, its secondary animation is kAlwaysDismissedAnimation.
-      ProxyAnimation secondaryAnimationProxyPageOne;
-      ProxyAnimation animationPageOne;
-      navigator.currentState.push(
+      late ProxyAnimation secondaryAnimationProxyPageOne;
+      late ProxyAnimation animationPageOne;
+      navigator.currentState!.push(
         PageRouteBuilder<void>(
           pageBuilder: (_, Animation<double> animation, Animation<double> secondaryAnimation) {
             secondaryAnimationProxyPageOne = secondaryAnimation as ProxyAnimation;
@@ -788,8 +786,8 @@ void main() {
 
       // Push page two, the secondary animation of page one is the primary
       // animation of page two.
-      ProxyAnimation animationPageTwo;
-      navigator.currentState.push(
+      late ProxyAnimation animationPageTwo;
+      navigator.currentState!.push(
         PageRouteBuilder<void>(
           pageBuilder: (_, Animation<double> animation, Animation<double> secondaryAnimation) {
             animationPageTwo = animation as ProxyAnimation;
@@ -803,8 +801,8 @@ void main() {
 
       // Replace with a different route while push is ongoing to trigger
       // TrainHopping.
-      ProxyAnimation animationPageThree;
-      navigator.currentState.pushReplacement(
+      late ProxyAnimation animationPageThree;
+      navigator.currentState!.pushReplacement(
         TestPageRouteBuilder(
           pageBuilder: (_, Animation<double> animation, Animation<double> secondaryAnimation) {
             animationPageThree = animation as ProxyAnimation;
@@ -825,7 +823,7 @@ void main() {
       expect(secondaryAnimationPageOne.parent, animationPageThree.parent);
 
       // Pop page three.
-      navigator.currentState.pop();
+      navigator.currentState!.pop();
       await tester.pump();
       await tester.pumpAndSettle();
       expect(secondaryAnimationPageOne.parent, kAlwaysDismissedAnimation);
@@ -841,9 +839,9 @@ void main() {
       );
 
       // Push page one, its secondary animation is kAlwaysDismissedAnimation.
-      ProxyAnimation secondaryAnimationProxyPageOne;
-      ProxyAnimation animationPageOne;
-      navigator.currentState.push(
+      late ProxyAnimation secondaryAnimationProxyPageOne;
+      late ProxyAnimation animationPageOne;
+      navigator.currentState!.push(
         PageRouteBuilder<void>(
           pageBuilder: (_, Animation<double> animation, Animation<double> secondaryAnimation) {
             secondaryAnimationProxyPageOne = secondaryAnimation as ProxyAnimation;
@@ -860,8 +858,8 @@ void main() {
 
       // Push page two, the secondary animation of page one is the primary
       // animation of page two.
-      ProxyAnimation animationPageTwo;
-      navigator.currentState.push(
+      late ProxyAnimation animationPageTwo;
+      navigator.currentState!.push(
         PageRouteBuilder<void>(
           pageBuilder: (_, Animation<double> animation, Animation<double> secondaryAnimation) {
             animationPageTwo = animation as ProxyAnimation;
@@ -875,7 +873,7 @@ void main() {
 
       // Replace with a different route while push is ongoing to trigger
       // TrainHopping.
-      navigator.currentState.pushReplacement(
+      navigator.currentState!.pushReplacement(
         TestPageRouteBuilder(
           pageBuilder: (_, Animation<double> animation, Animation<double> secondaryAnimation) {
             return const Text('Page Three');
@@ -889,7 +887,7 @@ void main() {
       expect(trainHopper.currentTrain, animationPageTwo.parent);
 
       // Pop page three while replacement push is ongoing.
-      navigator.currentState.pop();
+      navigator.currentState!.pop();
       await tester.pump();
       expect(secondaryAnimationPageOne.parent, isA<TrainHoppingAnimation>());
       final TrainHoppingAnimation trainHopper2 = secondaryAnimationPageOne.parent as TrainHoppingAnimation;
@@ -902,8 +900,8 @@ void main() {
 
     testWidgets('secondary animation is triggered when pop initial route', (WidgetTester tester) async {
       final GlobalKey<NavigatorState> navigator = GlobalKey<NavigatorState>();
-      Animation<double> secondaryAnimationOfRouteOne;
-      Animation<double> primaryAnimationOfRouteTwo;
+      late Animation<double> secondaryAnimationOfRouteOne;
+      late Animation<double> primaryAnimationOfRouteTwo;
       await tester.pumpWidget(
         MaterialApp(
           navigatorKey: navigator,
@@ -927,7 +925,7 @@ void main() {
       expect(secondaryAnimationOfRouteOne.value, 1.0);
       expect(secondaryAnimationOfRouteOne.value, primaryAnimationOfRouteTwo.value);
       // Pops the top most route and verifies two routes are still chained.
-      navigator.currentState.pop();
+      navigator.currentState!.pop();
       await tester.pump();
       await tester.pump(const Duration(milliseconds: 30));
       expect(secondaryAnimationOfRouteOne.value, 0.9);
@@ -1127,7 +1125,7 @@ void main() {
             builder: (BuildContext context) {
               return ElevatedButton(
                 onPressed: () {
-                  Navigator.of(context).push<void>(
+                  Navigator.of(context)!.push<void>(
                     MaterialPageRoute<void>(
                       builder: (BuildContext innerContext) {
                         return Container(
@@ -1177,7 +1175,7 @@ void main() {
             builder: (BuildContext context) {
               return ElevatedButton(
                 onPressed: () {
-                  Navigator.of(context).push<void>(
+                  Navigator.of(context)!.push<void>(
                     ModifiedReverseTransitionDurationRoute<void>(
                       builder: (BuildContext innerContext) {
                         return Container(
@@ -1236,7 +1234,7 @@ void main() {
             builder: (BuildContext context) {
               return ElevatedButton(
                 onPressed: () {
-                  Navigator.of(context).push<void>(
+                  Navigator.of(context)!.push<void>(
                     ModifiedReverseTransitionDurationRoute<void>(
                       builder: (BuildContext innerContext) {
                         return Container(
@@ -1298,7 +1296,7 @@ void main() {
                 child: ElevatedButton(
                   child: const Text('X'),
                   onPressed: () {
-                    Navigator.of(context).push<void>(
+                    Navigator.of(context)!.push<void>(
                       _TestDialogRouteWithCustomBarrierCurve<void>(
                         child: const Text('Hello World'),
                       )
@@ -1360,7 +1358,7 @@ void main() {
                 child: ElevatedButton(
                   child: const Text('X'),
                   onPressed: () {
-                    Navigator.of(context).push<void>(
+                    Navigator.of(context)!.push<void>(
                       _TestDialogRouteWithCustomBarrierCurve<void>(
                         child: const Text('Hello World'),
                         barrierCurve: Curves.linear,
@@ -1425,7 +1423,7 @@ void main() {
                 child: ElevatedButton(
                   child: const Text('X'),
                   onPressed: () {
-                    Navigator.of(context).push<void>(
+                    Navigator.of(context)!.push<void>(
                       _TestDialogRouteWithCustomBarrierCurve<void>(
                         child: const Text('Hello World'),
                         barrierLabel: 'test label',
@@ -1499,7 +1497,7 @@ void main() {
       expect(focusNodeOnPageOne.hasFocus, isTrue);
 
       // Pushes one page.
-      navigatorKey.currentState.push<void>(
+      navigatorKey.currentState!.push<void>(
         MaterialPageRoute<void>(
           builder: (BuildContext context) => const Text('dummy2'),
         )
@@ -1513,7 +1511,7 @@ void main() {
       expect(focusNodeOnPageTwo.hasFocus, isTrue);
 
       // Pushes another page.
-      navigatorKey.currentState.push<void>(
+      navigatorKey.currentState!.push<void>(
         MaterialPageRoute<void>(
           builder: (BuildContext context) => const Text('dummy3'),
         )
@@ -1527,7 +1525,7 @@ void main() {
       expect(focusNodeOnPageThree.hasFocus, isTrue);
 
       // Pops two pages simultaneously.
-      navigatorKey.currentState.popUntil((Route<void> route) => route.isFirst);
+      navigatorKey.currentState!.popUntil((Route<void> route) => route.isFirst);
       await tester.pumpAndSettle();
       // It should refocus page one after pops.
       expect(focusNodeOnPageOne.hasFocus, isTrue);
@@ -1545,7 +1543,7 @@ void main() {
       expect(focusNodeOnPageOne.hasFocus, isTrue);
 
       // Pushes one page.
-      navigatorKey.currentState.push<void>(
+      navigatorKey.currentState!.push<void>(
           MaterialPageRoute<void>(
             builder: (BuildContext context) => const Material(child: TextField()),
           )
@@ -1565,7 +1563,7 @@ void main() {
       expect(focusNodeOnPageTwo.hasPrimaryFocus, isFalse);
 
       // Pushes another page.
-      navigatorKey.currentState.push<void>(
+      navigatorKey.currentState!.push<void>(
           MaterialPageRoute<void>(
             builder: (BuildContext context) => const Text('dummy3'),
           )
@@ -1579,7 +1577,7 @@ void main() {
       expect(focusNodeOnPageThree.hasFocus, isTrue);
 
       // Pops two pages simultaneously.
-      navigatorKey.currentState.popUntil((Route<void> route) => route.isFirst);
+      navigatorKey.currentState!.popUntil((Route<void> route) => route.isFirst);
       await tester.pumpAndSettle();
       // It should refocus page one after pops.
       expect(focusNodeOnPageOne.hasFocus, isTrue);
@@ -1629,6 +1627,28 @@ void main() {
     await tester.pumpAndSettle();
     expect(find.text('dialog1'), findsNothing);
   });
+
+  testWidgets('ModalRoute.of works for void routes', (WidgetTester tester) async {
+    final GlobalKey<NavigatorState> navigatorKey = GlobalKey<NavigatorState>();
+    await tester.pumpWidget(MaterialApp(
+      navigatorKey: navigatorKey,
+      home: const Text('home'),
+    ));
+    expect(find.text('page2'), findsNothing);
+
+    navigatorKey.currentState!.push<void>(MaterialPageRoute<void>(
+      builder: (BuildContext context) {
+        return const Text('page2');
+      }
+    ));
+
+    await tester.pumpAndSettle();
+    expect(find.text('page2'), findsOneWidget);
+
+    final ModalRoute<void>? parentRoute = ModalRoute.of<void>(tester.element(find.text('page2')));
+    expect(parentRoute, isNotNull);
+    expect(parentRoute, isA<MaterialPageRoute<void>>());
+  });
 }
 
 double _getOpacity(GlobalKey key, WidgetTester tester) {
@@ -1644,9 +1664,9 @@ double _getOpacity(GlobalKey key, WidgetTester tester) {
 
 class ModifiedReverseTransitionDurationRoute<T> extends MaterialPageRoute<T> {
   ModifiedReverseTransitionDurationRoute({
-    @required WidgetBuilder builder,
-    RouteSettings settings,
-    this.reverseTransitionDuration,
+    required WidgetBuilder builder,
+    RouteSettings? settings,
+    required this.reverseTransitionDuration,
     bool fullscreenDialog = false,
   }) : super(
          builder: builder,
@@ -1690,7 +1710,7 @@ class MockRouteAware extends Fake implements RouteAware {
 }
 
 class TestPageRouteBuilder extends PageRouteBuilder<void> {
-  TestPageRouteBuilder({RoutePageBuilder pageBuilder}) : super(pageBuilder: pageBuilder);
+  TestPageRouteBuilder({required RoutePageBuilder pageBuilder}) : super(pageBuilder: pageBuilder);
 
   @override
   Animation<double> createAnimation() {
@@ -1703,7 +1723,7 @@ class DialogObserver extends NavigatorObserver {
   int dialogCount = 0;
 
   @override
-  void didPush(Route<dynamic> route, Route<dynamic> previousRoute) {
+  void didPush(Route<dynamic> route, Route<dynamic>? previousRoute) {
     if (route.toString().contains('_DialogRoute')) {
       dialogRoutes.add(route as ModalRoute<dynamic>);
       dialogCount++;
@@ -1712,7 +1732,7 @@ class DialogObserver extends NavigatorObserver {
   }
 
   @override
-  void didPop(Route<dynamic> route, Route<dynamic> previousRoute) {
+  void didPop(Route<dynamic> route, Route<dynamic>? previousRoute) {
     if (route.toString().contains('_DialogRoute')) {
       dialogRoutes.removeLast();
       dialogCount--;
@@ -1723,9 +1743,9 @@ class DialogObserver extends NavigatorObserver {
 
 class _TestDialogRouteWithCustomBarrierCurve<T> extends PopupRoute<T> {
   _TestDialogRouteWithCustomBarrierCurve({
-    @required Widget child,
+    required Widget child,
     this.barrierLabel,
-    Curve barrierCurve,
+    Curve? barrierCurve,
   }) : _barrierCurve = barrierCurve,
        _child = child;
 
@@ -1735,7 +1755,7 @@ class _TestDialogRouteWithCustomBarrierCurve<T> extends PopupRoute<T> {
   bool get barrierDismissible => true;
 
   @override
-  final String barrierLabel;
+  final String? barrierLabel;
 
   @override
   Color get barrierColor => Colors.black; // easier value to test against
@@ -1745,9 +1765,9 @@ class _TestDialogRouteWithCustomBarrierCurve<T> extends PopupRoute<T> {
     if (_barrierCurve == null) {
       return super.barrierCurve;
     }
-    return _barrierCurve;
+    return _barrierCurve!;
   }
-  final Curve _barrierCurve;
+  final Curve? _barrierCurve;
 
   @override
   Duration get transitionDuration => const Duration(milliseconds: 100); // easier value to test against
@@ -1768,10 +1788,10 @@ class WidgetWithLocalHistory extends StatefulWidget {
 }
 
 class WidgetWithLocalHistoryState extends State<WidgetWithLocalHistory> {
-  LocalHistoryEntry _localHistory;
+  late LocalHistoryEntry _localHistory;
 
   void addLocalHistory() {
-    final ModalRoute<dynamic> route = ModalRoute.of(context);
+    final ModalRoute<dynamic> route = ModalRoute.of(context)!;
     _localHistory = LocalHistoryEntry();
     route.addLocalHistoryEntry(_localHistory);
   }
@@ -1792,9 +1812,9 @@ class TransitionDetector extends DefaultTransitionDelegate<void> {
   bool hasTransition = false;
   @override
   Iterable<RouteTransitionRecord> resolve({
-    List<RouteTransitionRecord> newPageRouteHistory,
-    Map<RouteTransitionRecord, RouteTransitionRecord> locationToExitingPageRoute,
-    Map<RouteTransitionRecord, List<RouteTransitionRecord>> pageRouteToPagelessRoutes
+    required List<RouteTransitionRecord> newPageRouteHistory,
+    required Map<RouteTransitionRecord?, RouteTransitionRecord> locationToExitingPageRoute,
+    required Map<RouteTransitionRecord?, List<RouteTransitionRecord>> pageRouteToPagelessRoutes
   }) {
     hasTransition = true;
     return super.resolve(
@@ -1806,13 +1826,13 @@ class TransitionDetector extends DefaultTransitionDelegate<void> {
 }
 
 Widget buildNavigator({
-  List<Page<dynamic>> pages,
-  PopPageCallback onPopPage,
-  GlobalKey<NavigatorState> key,
-  TransitionDelegate<dynamic> transitionDelegate
+  required List<Page<dynamic>> pages,
+  required PopPageCallback onPopPage,
+  GlobalKey<NavigatorState>? key,
+  TransitionDelegate<dynamic>? transitionDelegate
 }) {
   return MediaQuery(
-    data: MediaQueryData.fromWindow(WidgetsBinding.instance.window),
+    data: MediaQueryData.fromWindow(WidgetsBinding.instance!.window),
     child: Localizations(
       locale: const Locale('en', 'US'),
       delegates: const <LocalizationsDelegate<dynamic>>[