flutter · fluttergithubbot · Oct 15, 2020 · Oct 15, 2020
diff --git a/packages/flutter/lib/src/rendering/tweens.dart b/packages/flutter/lib/src/rendering/tweens.dart
@@ -39,7 +39,7 @@ class FractionalOffsetTween extends Tween<FractionalOffset?> {
 ///
 ///  * [AlignmentGeometryTween], which interpolates between two
 ///    [AlignmentGeometry] objects.
-class AlignmentTween extends Tween<Alignment?> {
+class AlignmentTween extends Tween<Alignment> {
   /// Creates a fractional offset tween.
   ///
   /// The [begin] and [end] properties may be null; the null value
@@ -49,7 +49,7 @@ class AlignmentTween extends Tween<Alignment?> {
 
   /// Returns the value this variable has at the given animation clock value.
   @override
-  Alignment? lerp(double t) => Alignment.lerp(begin, end, t);
+  Alignment lerp(double t) => Alignment.lerp(begin, end, t)!;
 }
 
 /// An interpolation between two [AlignmentGeometry].

diff --git a/packages/flutter/lib/src/widgets/value_listenable_builder.dart b/packages/flutter/lib/src/widgets/value_listenable_builder.dart
@@ -16,7 +16,7 @@ import 'framework.dart';
 ///
 ///  * [ValueListenableBuilder], a widget which invokes this builder each time
 ///    a [ValueListenable] changes value.
-typedef ValueWidgetBuilder<T> = Widget Function(BuildContext context, T? value, Widget? child);
+typedef ValueWidgetBuilder<T> = Widget Function(BuildContext context, T value, Widget? child);
 
 /// A widget whose content stays synced with a [ValueListenable].
 ///
@@ -153,7 +153,7 @@ class ValueListenableBuilder<T> extends StatefulWidget {
 }
 
 class _ValueListenableBuilderState<T> extends State<ValueListenableBuilder<T>> {
-  T? value;
+  late T value;
 
   @override
   void initState() {

diff --git a/packages/flutter/test/widgets/transitions_test.dart b/packages/flutter/test/widgets/transitions_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:math' as math;
 
 import 'package:flutter/material.dart';
@@ -50,7 +48,7 @@ void main() {
       ),
     );
 
-    AnimationController controller;
+    late AnimationController controller;
 
     setUp(() {
       controller = AnimationController(vsync: const TestVSync());
@@ -71,9 +69,9 @@ void main() {
       BoxDecoration actualDecoration = actualBox.decoration as BoxDecoration;
 
       expect(actualDecoration.color, const Color(0xFFFFFFFF));
-      expect(actualDecoration.boxShadow[0].blurRadius, 10.0);
-      expect(actualDecoration.boxShadow[0].spreadRadius, 4.0);
-      expect(actualDecoration.boxShadow[0].color, const Color(0x66000000));
+      expect(actualDecoration.boxShadow![0].blurRadius, 10.0);
+      expect(actualDecoration.boxShadow![0].spreadRadius, 4.0);
+      expect(actualDecoration.boxShadow![0].color, const Color(0x66000000));
 
       controller.value = 0.5;
 
@@ -83,16 +81,16 @@ void main() {
 
       expect(actualDecoration.color, const Color(0xFF7F7F7F));
       expect(actualDecoration.border, isA<Border>());
-      final Border border = actualDecoration.border as Border;
+      final Border border = actualDecoration.border! as Border;
       expect(border.left.width, 2.5);
       expect(border.left.style, BorderStyle.solid);
       expect(border.left.color, const Color(0xFF101010));
       expect(actualDecoration.borderRadius, BorderRadius.circular(5.0));
       expect(actualDecoration.shape, BoxShape.rectangle);
-      expect(actualDecoration.boxShadow[0].blurRadius, 5.0);
-      expect(actualDecoration.boxShadow[0].spreadRadius, 2.0);
+      expect(actualDecoration.boxShadow![0].blurRadius, 5.0);
+      expect(actualDecoration.boxShadow![0].spreadRadius, 2.0);
       // Scaling a shadow doesn't change the color.
-      expect(actualDecoration.boxShadow[0].color, const Color(0x66000000));
+      expect(actualDecoration.boxShadow![0].color, const Color(0x66000000));
 
       controller.value = 1.0;
 
@@ -126,9 +124,9 @@ void main() {
       BoxDecoration actualDecoration = actualBox.decoration as BoxDecoration;
 
       expect(actualDecoration.color, const Color(0xFFFFFFFF));
-      expect(actualDecoration.boxShadow[0].blurRadius, 10.0);
-      expect(actualDecoration.boxShadow[0].spreadRadius, 4.0);
-      expect(actualDecoration.boxShadow[0].color, const Color(0x66000000));
+      expect(actualDecoration.boxShadow![0].blurRadius, 10.0);
+      expect(actualDecoration.boxShadow![0].spreadRadius, 4.0);
+      expect(actualDecoration.boxShadow![0].color, const Color(0x66000000));
 
       controller.value = 0.5;
 
@@ -140,16 +138,16 @@ void main() {
       // tween's end values given the easeOut curve.
       expect(actualDecoration.color, const Color(0xFF505050));
       expect(actualDecoration.border, isA<Border>());
-      final Border border = actualDecoration.border as Border;
+      final Border border = actualDecoration.border! as Border;
       expect(border.left.width, moreOrLessEquals(1.9, epsilon: 0.1));
       expect(border.left.style, BorderStyle.solid);
       expect(border.left.color, const Color(0xFF151515));
-      expect(actualDecoration.borderRadius.resolve(TextDirection.ltr).topLeft.x, moreOrLessEquals(6.8, epsilon: 0.1));
+      expect(actualDecoration.borderRadius!.resolve(TextDirection.ltr).topLeft.x, moreOrLessEquals(6.8, epsilon: 0.1));
       expect(actualDecoration.shape, BoxShape.rectangle);
-      expect(actualDecoration.boxShadow[0].blurRadius, moreOrLessEquals(3.1, epsilon: 0.1));
-      expect(actualDecoration.boxShadow[0].spreadRadius, moreOrLessEquals(1.2, epsilon: 0.1));
+      expect(actualDecoration.boxShadow![0].blurRadius, moreOrLessEquals(3.1, epsilon: 0.1));
+      expect(actualDecoration.boxShadow![0].spreadRadius, moreOrLessEquals(1.2, epsilon: 0.1));
       // Scaling a shadow doesn't change the color.
-      expect(actualDecoration.boxShadow[0].color, const Color(0x66000000));
+      expect(actualDecoration.boxShadow![0].color, const Color(0x66000000));
     });
   });
 

diff --git a/packages/flutter/test/widgets/tween_animation_builder_test.dart b/packages/flutter/test/widgets/tween_animation_builder_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 'package:flutter_test/flutter_test.dart';
 import 'package:flutter/widgets.dart';
 
@@ -15,7 +13,7 @@ void main() {
       TweenAnimationBuilder<int>(
         duration: const Duration(seconds: 1),
         tween: IntTween(begin: 10, end: 110),
-        builder: (BuildContext context, int i, Widget child) {
+        builder: (BuildContext context, int i, Widget? child) {
           values.add(i);
           return const Placeholder();
         },
@@ -46,7 +44,7 @@ void main() {
       TweenAnimationBuilder<int>(
         duration: const Duration(seconds: 1),
         tween: IntTween(end: 100),
-        builder: (BuildContext context, int i, Widget child) {
+        builder: (BuildContext context, int i, Widget? child) {
           values.add(i);
           return const Placeholder();
         },
@@ -70,7 +68,7 @@ void main() {
       TweenAnimationBuilder<int>(
         duration: const Duration(seconds: 1),
         tween: IntTween(begin: 100, end: 100),
-        builder: (BuildContext context, int i, Widget child) {
+        builder: (BuildContext context, int i, Widget? child) {
           values.add(i);
           return const Placeholder();
         },
@@ -88,11 +86,11 @@ void main() {
 
   testWidgets('Replace tween animates new tween', (WidgetTester tester) async {
     final List<int> values = <int>[];
-    Widget buildWidget({IntTween tween}) {
+    Widget buildWidget({required IntTween tween}) {
       return TweenAnimationBuilder<int>(
         duration: const Duration(seconds: 1),
         tween: tween,
-        builder: (BuildContext context, int i, Widget child) {
+        builder: (BuildContext context, int i, Widget? child) {
           values.add(i);
           return const Placeholder();
         },
@@ -116,12 +114,12 @@ void main() {
 
   testWidgets('Curve is respected', (WidgetTester tester) async {
     final List<int> values = <int>[];
-    Widget buildWidget({IntTween tween, Curve curve}) {
+    Widget buildWidget({required IntTween tween, required Curve curve}) {
       return TweenAnimationBuilder<int>(
         duration: const Duration(seconds: 1),
         tween: tween,
         curve: curve,
-        builder: (BuildContext context, int i, Widget child) {
+        builder: (BuildContext context, int i, Widget? child) {
           values.add(i);
           return const Placeholder();
         },
@@ -146,11 +144,11 @@ void main() {
 
   testWidgets('Duration is respected', (WidgetTester tester) async {
     final List<int> values = <int>[];
-    Widget buildWidget({IntTween tween, Duration duration}) {
+    Widget buildWidget({required IntTween tween, required Duration duration}) {
       return TweenAnimationBuilder<int>(
         tween: tween,
         duration: duration,
-        builder: (BuildContext context, int i, Widget child) {
+        builder: (BuildContext context, int i, Widget? child) {
           values.add(i);
           return const Placeholder();
         },
@@ -179,8 +177,8 @@ void main() {
         child: TweenAnimationBuilder<int>(
           tween: IntTween(begin: 0, end: 100),
           duration: const Duration(seconds: 1),
-          builder: (BuildContext context, int i, Widget child) {
-            return child;
+          builder: (BuildContext context, int i, Widget? child) {
+            return child!;
           },
           child: const Text('Hello World'),
         ),
@@ -193,11 +191,11 @@ void main() {
   group('Change tween gapless while', () {
     testWidgets('running forward', (WidgetTester tester) async {
       final List<int> values = <int>[];
-      Widget buildWidget({IntTween tween}) {
+      Widget buildWidget({required IntTween tween}) {
         return TweenAnimationBuilder<int>(
           tween: tween,
           duration: const Duration(seconds: 1),
-          builder: (BuildContext context, int i, Widget child) {
+          builder: (BuildContext context, int i, Widget? child) {
             values.add(i);
             return const Placeholder();
           },
@@ -228,11 +226,11 @@ void main() {
 
     testWidgets('running forward and then reverse with same tween instance', (WidgetTester tester) async {
       final List<int> values = <int>[];
-      Widget buildWidget({IntTween tween}) {
+      Widget buildWidget({required IntTween tween}) {
         return TweenAnimationBuilder<int>(
           tween: tween,
           duration: const Duration(seconds: 1),
-          builder: (BuildContext context, int i, Widget child) {
+          builder: (BuildContext context, int i, Widget? child) {
             values.add(i);
             return const Placeholder();
           },
@@ -258,11 +256,11 @@ void main() {
 
   testWidgets('Changing tween while gapless tween change is in progress', (WidgetTester tester) async {
     final List<int> values = <int>[];
-    Widget buildWidget({IntTween tween}) {
+    Widget buildWidget({required IntTween tween}) {
       return TweenAnimationBuilder<int>(
         tween: tween,
         duration: const Duration(seconds: 1),
-        builder: (BuildContext context, int i, Widget child) {
+        builder: (BuildContext context, int i, Widget? child) {
           values.add(i);
           return const Placeholder();
         },
@@ -298,12 +296,12 @@ void main() {
 
   testWidgets('Changing curve while no animation is running does not trigger animation', (WidgetTester tester) async {
     final List<int> values = <int>[];
-    Widget buildWidget({Curve curve}) {
+    Widget buildWidget({required Curve curve}) {
       return TweenAnimationBuilder<int>(
         tween: IntTween(begin: 0, end: 100),
         curve: curve,
         duration: const Duration(seconds: 1),
-        builder: (BuildContext context, int i, Widget child) {
+        builder: (BuildContext context, int i, Widget? child) {
           values.add(i);
           return const Placeholder();
         },
@@ -327,11 +325,11 @@ void main() {
 
   testWidgets('Setting same tween and direction does not trigger animation', (WidgetTester tester) async {
     final List<int> values = <int>[];
-    Widget buildWidget({IntTween tween}) {
+    Widget buildWidget({required IntTween tween}) {
       return TweenAnimationBuilder<int>(
         tween: tween,
         duration: const Duration(seconds: 1),
-        builder: (BuildContext context, int i, Widget child) {
+        builder: (BuildContext context, int i, Widget? child) {
           values.add(i);
           return const Placeholder();
         },
@@ -356,11 +354,11 @@ void main() {
 
   testWidgets('Setting same tween and direction while gapless animation is in progress works', (WidgetTester tester) async {
     final List<int> values = <int>[];
-    Widget buildWidget({IntTween tween}) {
+    Widget buildWidget({required IntTween tween}) {
       return TweenAnimationBuilder<int>(
         tween: tween,
         duration: const Duration(seconds: 1),
-        builder: (BuildContext context, int i, Widget child) {
+        builder: (BuildContext context, int i, Widget? child) {
           values.add(i);
           return const Placeholder();
         },

diff --git a/packages/flutter/test/widgets/unique_widget_test.dart b/packages/flutter/test/widgets/unique_widget_test.dart
@@ -2,13 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_test/flutter_test.dart';
 import 'package:flutter/widgets.dart';
 
 class TestUniqueWidget extends UniqueWidget<TestUniqueWidgetState> {
-  const TestUniqueWidget({ GlobalKey<TestUniqueWidgetState> key }) : super(key: key);
+  const TestUniqueWidget({ required GlobalKey<TestUniqueWidgetState> key }) : super(key: key);
 
   @override
   TestUniqueWidgetState createState() => TestUniqueWidgetState();
@@ -25,7 +23,7 @@ void main() {
 
     await tester.pumpWidget(widget);
 
-    final TestUniqueWidgetState state = widget.currentState;
+    final TestUniqueWidgetState state = widget.currentState!;
 
     expect(state, isNotNull);
 

diff --git a/packages/flutter/test/widgets/value_listenable_builder_test.dart b/packages/flutter/test/widgets/value_listenable_builder_test.dart
@@ -2,24 +2,22 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_test/flutter_test.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/widgets.dart';
 
 void main() {
-  SpyStringValueNotifier valueListenable;
-  Widget textBuilderUnderTest;
+  late SpyStringValueNotifier valueListenable;
+  late Widget textBuilderUnderTest;
 
   Widget builderForValueListenable(
-    ValueListenable<String> valueListenable,
+    ValueListenable<String?> valueListenable,
   ) {
     return Directionality(
       textDirection: TextDirection.ltr,
-      child: ValueListenableBuilder<String>(
+      child: ValueListenableBuilder<String?>(
         valueListenable: valueListenable,
-        builder: (BuildContext context, String value, Widget child) {
+        builder: (BuildContext context, String? value, Widget? child) {
           if (value == null)
             return const Placeholder();
           return Text(value);
@@ -67,7 +65,7 @@ void main() {
     await tester.pump();
     expect(find.text('Gilfoyle'), findsOneWidget);
 
-    final ValueListenable<String> differentListenable =
+    final ValueListenable<String?> differentListenable =
         SpyStringValueNotifier('Hendricks');
 
     await tester.pumpWidget(builderForValueListenable(differentListenable));
@@ -83,7 +81,7 @@ void main() {
     await tester.pump();
     expect(find.text('Gilfoyle'), findsOneWidget);
 
-    final ValueListenable<String> differentListenable =
+    final ValueListenable<String?> differentListenable =
        SpyStringValueNotifier('Hendricks');
 
     await tester.pumpWidget(builderForValueListenable(differentListenable));
@@ -113,8 +111,8 @@ void main() {
   });
 }
 
-class SpyStringValueNotifier extends ValueNotifier<String> {
-  SpyStringValueNotifier(String initialValue) : super(initialValue);
+class SpyStringValueNotifier extends ValueNotifier<String?> {
+  SpyStringValueNotifier(String? initialValue) : super(initialValue);
 
   /// Override for test visibility only.
   @override

diff --git a/packages/flutter/test/widgets/visibility_test.dart b/packages/flutter/test/widgets/visibility_test.dart
@@ -2,16 +2,14 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 import '../rendering/mock_canvas.dart';
 import 'semantics_tester.dart';
 
 class TestState extends StatefulWidget {
-  const TestState({ Key key, this.child, this.log }) : super(key: key);
+  const TestState({ Key? key, required this.child, required this.log }) : super(key: key);
   final Widget child;
   final List<String> log;
   @override