Make Flex,Row,Column const for real (#119673)

* Make Flex,Row,Column const for real

* dart fix --apply

* fix snippets

* fix integration test

* add comment

dev/automated_tests/flutter_test/print_correct_local_widget_test.dart

@@ -14,15 +14,15 @@ void main() {
           appBar: AppBar(
             title: const Text('RenderFlex OverFlow'),
           ),
-          body: SizedBox(
+          body: const SizedBox(
             width: 400.0,
             child: Row(
               children: <Widget>[
-                const Icon(Icons.message),
+                Icon(Icons.message),
                 Column(
                   mainAxisSize: MainAxisSize.min,
                   crossAxisAlignment: CrossAxisAlignment.start,
-                  children: const <Widget>[
+                  children: <Widget>[
                     Text('Title'),
                     Text(
                       'Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed '

dev/benchmarks/complex_layout/lib/src/app.dart

@@ -279,11 +279,11 @@ class IconBar extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return Padding(
-      padding: const EdgeInsets.only(left: 16.0, right: 16.0),
+    return const Padding(
+      padding: EdgeInsets.only(left: 16.0, right: 16.0),
       child: Row(
         mainAxisAlignment: MainAxisAlignment.spaceBetween,
-        children: const <Widget>[
+        children: <Widget>[
           IconWithText(Icons.thumb_up, 'Like'),
           IconWithText(Icons.comment, 'Comment'),
           IconWithText(Icons.share, 'Share'),
@@ -578,9 +578,9 @@ class BottomBar extends StatelessWidget {
           ),
         ),
       ),
-      child: Row(
+      child: const Row(
         mainAxisAlignment: MainAxisAlignment.spaceBetween,
-        children: const <Widget>[
+        children: <Widget>[
           BottomBarButton(Icons.new_releases, 'News'),
           BottomBarButton(Icons.people, 'Requests'),
           BottomBarButton(Icons.chat, 'Messenger'),

dev/benchmarks/macrobenchmarks/lib/src/cubic_bezier.dart

@@ -12,10 +12,10 @@ class CubicBezierPage extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return Center(
+    return const Center(
       child: Column(
         mainAxisAlignment: MainAxisAlignment.center,
-        children: const <Widget>[
+        children: <Widget>[
           Bezier(Colors.amber, 1.0),
         ],
       ),

dev/benchmarks/macrobenchmarks/lib/src/stack_size.dart

@@ -88,9 +88,9 @@ class StackSizePage extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return Material(
+    return const Material(
       child: Column(
-        children: const <Widget>[
+        children: <Widget>[
           SizedBox(
             width: 200,
             height: 100,

dev/benchmarks/macrobenchmarks/lib/src/text.dart

@@ -9,10 +9,10 @@ class TextPage extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return Material(
+    return const Material(
       child: Column(
         mainAxisAlignment: MainAxisAlignment.center,
-        children: const <Widget>[
+        children: <Widget>[
           SizedBox(
             width: 200,
             height: 100,

dev/benchmarks/macrobenchmarks/lib/src/web/bench_simple_lazy_text_scroll.dart

@@ -20,10 +20,10 @@ class BenchSimpleLazyTextScroll extends WidgetRecorder {
 
   @override
   Widget createWidget() {
-    return Directionality(
+    return const Directionality(
       textDirection: TextDirection.ltr,
       child: Row(
-        children: const <Widget>[
+        children: <Widget>[
           Flexible(
             child: _TestScrollingWidget(
               initialScrollOffset: 0,

dev/benchmarks/microbenchmarks/lib/foundation/all_elements_bench.dart

@@ -28,8 +28,8 @@ Future<void> main() async {
                   Icon(Icons.ac_unit),
                 ],
               ),
-              body: Column(
-                children: const <Widget>[
+              body: const Column(
+                children: <Widget>[
                   Text('Item 1'),
                   Text('Item 2'),
                   Text('Item 3'),

dev/benchmarks/test_apps/stocks/lib/stock_home.dart

@@ -345,8 +345,8 @@ class _CreateCompanySheet extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return Column(
-      children: const <Widget>[
+    return const Column(
+      children: <Widget>[
         TextField(
           autofocus: true,
           decoration: InputDecoration(

dev/integration_tests/abstract_method_smoke_test/lib/main.dart

@@ -59,9 +59,9 @@ class SecondPage extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return Scaffold(
+    return const Scaffold(
       body: Column(
-        children: const <Widget>[
+        children: <Widget>[
           Expanded(
             child: AndroidView(viewType: 'simple')
           ),

dev/integration_tests/flutter_gallery/lib/demo/cupertino/cupertino_switch_demo.dart

@@ -57,8 +57,8 @@ class _CupertinoSwitchDemoState extends State<CupertinoSwitchDemo> {
                 ),
                 Semantics(
                   container: true,
-                  child: Column(
-                    children: const <Widget>[
+                  child: const Column(
+                    children: <Widget>[
                       CupertinoSwitch(
                         value: true,
                         onChanged: null,
@@ -71,8 +71,8 @@ class _CupertinoSwitchDemoState extends State<CupertinoSwitchDemo> {
                 ),
                 Semantics(
                   container: true,
-                  child: Column(
-                    children: const <Widget>[
+                  child: const Column(
+                    children: <Widget>[
                       CupertinoSwitch(
                         value: false,
                         onChanged: null,

dev/integration_tests/flutter_gallery/lib/demo/material/bottom_app_bar_demo.dart

@@ -402,9 +402,9 @@ class _DemoDrawer extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return Drawer(
+    return const Drawer(
       child: Column(
-        children: const <Widget>[
+        children: <Widget>[
           ListTile(
             leading: Icon(Icons.search),
             title: Text('Search'),

dev/integration_tests/flutter_gallery/lib/demo/material/search_demo.dart

@@ -70,13 +70,13 @@ class _SearchDemoState extends State<SearchDemo> {
         child: Column(
           mainAxisAlignment: MainAxisAlignment.center,
           children: <Widget>[
-            MergeSemantics(
+            const MergeSemantics(
               child: Column(
                 mainAxisAlignment: MainAxisAlignment.center,
                 children: <Widget>[
                   Row(
                     mainAxisAlignment: MainAxisAlignment.center,
-                    children: const <Widget>[
+                    children: <Widget>[
                       Text('Press the '),
                       Tooltip(
                         message: 'search',
@@ -88,7 +88,7 @@ class _SearchDemoState extends State<SearchDemo> {
                       Text(' icon in the AppBar'),
                     ],
                   ),
-                  const Text('and search for an integer between 0 and 100,000.'),
+                  Text('and search for an integer between 0 and 100,000.'),
                 ],
               ),
             ),

dev/integration_tests/flutter_gallery/lib/demo/material/selection_controls_demo.dart

@@ -126,9 +126,9 @@ class _SelectionControlsDemoState extends State<SelectionControlsDemo> {
               ),
             ],
           ),
-          Row(
+          const Row(
             mainAxisSize: MainAxisSize.min,
-            children: const <Widget>[
+            children: <Widget>[
               // Disabled checkboxes
               Checkbox(value: true, onChanged: null),
               Checkbox(value: false, onChanged: null),
@@ -167,9 +167,9 @@ class _SelectionControlsDemoState extends State<SelectionControlsDemo> {
             ],
           ),
           // Disabled radio buttons
-          Row(
+          const Row(
             mainAxisSize: MainAxisSize.min,
-            children: const <Widget>[
+            children: <Widget>[
               Radio<int>(
                 value: 0,
                 groupValue: 0,

dev/integration_tests/flutter_gallery/lib/demo/material/slider_demo.dart

@@ -296,9 +296,9 @@ class _SlidersState extends State<_Sliders> {
               const Text('Continuous with Editable Numerical Value'),
             ],
           ),
-          Column(
+          const Column(
             mainAxisSize: MainAxisSize.min,
-            children: const <Widget>[
+            children: <Widget>[
               Slider.adaptive(value: 0.25, onChanged: null),
               Text('Disabled'),
             ],

dev/integration_tests/flutter_gallery/lib/demo/transformations/transformations_demo.dart

@@ -93,10 +93,10 @@ class _TransformationsDemoState extends State<TransformationsDemo> {
   Widget get instructionDialog {
     return AlertDialog(
       title: const Text('2D Transformations'),
-      content: Column(
+      content: const Column(
         crossAxisAlignment: CrossAxisAlignment.start,
         mainAxisSize: MainAxisSize.min,
-        children: const <Widget>[
+        children: <Widget>[
           Text('Tap to edit hex tiles, and use gestures to move around the scene:\n'),
           Text('- Drag to pan.'),
           Text('- Pinch to zoom.'),

dev/integration_tests/ui/lib/overflow.dart

@@ -29,7 +29,7 @@ class _TestState extends State<Test> {
     if (!_triggered) {
       return const SizedBox.shrink();
     }
-    return Row(children: const <Widget>[
+    return const Row(children: <Widget>[
       SizedBox(width: 10000.0),
       SizedBox(width: 10000.0),
       SizedBox(width: 10000.0),

dev/integration_tests/web/lib/service_worker_test_cached_resources.dart

@@ -5,10 +5,10 @@
 import 'package:flutter/material.dart';
 
 Future<void> main() async {
-  runApp(Scaffold(
+  runApp(const Scaffold(
     body: Center(
       child: Column(
-        children: const <Widget>[
+        children: <Widget>[
           Icon(Icons.ac_unit),
           Text('Hello, World', textDirection: TextDirection.ltr),
         ],

dev/manual_tests/lib/actions.dart

@@ -432,25 +432,25 @@ class _FocusDemoState extends State<FocusDemo> {
                     return Column(
                       mainAxisAlignment: MainAxisAlignment.center,
                       children: <Widget>[
-                        Row(
+                        const Row(
                           mainAxisAlignment: MainAxisAlignment.center,
-                          children: const <Widget>[
+                          children: <Widget>[
                             DemoButton(name: 'One'),
                             DemoButton(name: 'Two'),
                             DemoButton(name: 'Three'),
                           ],
                         ),
-                        Row(
+                        const Row(
                           mainAxisAlignment: MainAxisAlignment.center,
-                          children: const <Widget>[
+                          children: <Widget>[
                             DemoButton(name: 'Four'),
                             DemoButton(name: 'Five'),
                             DemoButton(name: 'Six'),
                           ],
                         ),
-                        Row(
+                        const Row(
                           mainAxisAlignment: MainAxisAlignment.center,
-                          children: const <Widget>[
+                          children: <Widget>[
                             DemoButton(name: 'Seven'),
                             DemoButton(name: 'Eight'),
                             DemoButton(name: 'Nine'),

dev/manual_tests/lib/drag_and_drop.dart

@@ -270,9 +270,9 @@ class DragAndDropAppState extends State<DragAndDropApp> {
               ],
             ),
           ),
-          Expanded(
+          const Expanded(
             child: Row(
-              children: const <Widget>[
+              children: <Widget>[
                 Expanded(child: ExampleDragTarget()),
                 Expanded(child: ExampleDragTarget()),
                 Expanded(child: ExampleDragTarget()),

dev/manual_tests/lib/focus.dart

@@ -152,18 +152,18 @@ class _FocusDemoState extends State<FocusDemo> {
                 return Column(
                   mainAxisAlignment: MainAxisAlignment.center,
                   children: <Widget>[
-                    Row(
+                    const Row(
                       mainAxisAlignment: MainAxisAlignment.center,
-                      children: const <Widget>[
+                      children: <Widget>[
                         DemoButton(
                           name: 'One',
                           autofocus: true,
                         ),
                       ],
                     ),
-                    Row(
+                    const Row(
                       mainAxisAlignment: MainAxisAlignment.center,
-                      children: const <Widget>[
+                      children: <Widget>[
                         DemoButton(name: 'Two'),
                         DemoButton(
                           name: 'Three',
@@ -171,9 +171,9 @@ class _FocusDemoState extends State<FocusDemo> {
                         ),
                       ],
                     ),
-                    Row(
+                    const Row(
                       mainAxisAlignment: MainAxisAlignment.center,
-                      children: const <Widget>[
+                      children: <Widget>[
                         DemoButton(name: 'Four'),
                         DemoButton(name: 'Five'),
                         DemoButton(name: 'Six'),

dev/tracing_tests/test/inflate_widget_tracing_test.dart

@@ -65,8 +65,8 @@ class TestRootState extends State<TestRoot> {
   @override
   Widget build(BuildContext context) {
     return _showRow
-      ? Row(
-          children: const <Widget>[
+      ? const Row(
+          children: <Widget>[
             TestChildWidget(),
             TestChildWidget(),
           ],

examples/api/lib/cupertino/activity_indicator/cupertino_activity_indicator.0.dart

@@ -25,8 +25,8 @@ class CupertinoIndicatorExample extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return CupertinoPageScaffold(
-      navigationBar: const CupertinoNavigationBar(
+    return const CupertinoPageScaffold(
+      navigationBar: CupertinoNavigationBar(
         middle: Text('CupertinoActivityIndicator Sample'),
       ),
       child: Center(
@@ -35,7 +35,7 @@ class CupertinoIndicatorExample extends StatelessWidget {
           children: <Widget>[
             Column(
               mainAxisAlignment: MainAxisAlignment.center,
-              children: const <Widget>[
+              children: <Widget>[
                 // Cupertino activity indicator with default properties.
                 CupertinoActivityIndicator(),
                 SizedBox(height: 10),
@@ -44,7 +44,7 @@ class CupertinoIndicatorExample extends StatelessWidget {
             ),
             Column(
               mainAxisAlignment: MainAxisAlignment.center,
-              children: const <Widget>[
+              children: <Widget>[
                 // Cupertino activity indicator with custom radius and color.
                 CupertinoActivityIndicator(radius: 20.0, color: CupertinoColors.activeBlue),
                 SizedBox(height: 10),
@@ -56,7 +56,7 @@ class CupertinoIndicatorExample extends StatelessWidget {
             ),
             Column(
               mainAxisAlignment: MainAxisAlignment.center,
-              children: const <Widget>[
+              children: <Widget>[
                 // Cupertino activity indicator with custom radius and disabled
                 // animation.
                 CupertinoActivityIndicator(radius: 20.0, animating: false),

examples/api/lib/cupertino/form_row/cupertino_form_row.0.dart

@@ -56,33 +56,33 @@ class _CupertinoFormRowExampleState extends State<CupertinoFormRowExample> {
                 },
               ),
             ),
-            CupertinoFormRow(
-              prefix: const PrefixWidget(
+            const CupertinoFormRow(
+              prefix: PrefixWidget(
                 icon: CupertinoIcons.wifi,
                 title: 'Wi-Fi',
                 color: CupertinoColors.systemBlue,
               ),
-              error: const Text('Home network unavailable'),
+              error: Text('Home network unavailable'),
               child: Row(
                 mainAxisAlignment: MainAxisAlignment.end,
-                children: const <Widget>[
+                children: <Widget>[
                   Text('Not connected'),
                   SizedBox(width: 5),
                   Icon(CupertinoIcons.forward)
                 ],
               ),
             ),
-            CupertinoFormRow(
-              prefix: const PrefixWidget(
+            const CupertinoFormRow(
+              prefix: PrefixWidget(
                 icon: CupertinoIcons.bluetooth,
                 title: 'Bluetooth',
                 color: CupertinoColors.activeBlue,
               ),
               helper: Padding(
-                padding: const EdgeInsets.symmetric(vertical: 4.0),
+                padding: EdgeInsets.symmetric(vertical: 4.0),
                 child: Row(
                   mainAxisAlignment: MainAxisAlignment.spaceBetween,
-                  children: const <Widget>[
+                  children: <Widget>[
                     Text('Headphone'),
                     Text('Connected'),
                   ],
@@ -90,7 +90,7 @@ class _CupertinoFormRowExampleState extends State<CupertinoFormRowExample> {
               ),
               child: Row(
                 mainAxisAlignment: MainAxisAlignment.end,
-                children: const <Widget>[
+                children: <Widget>[
                   Text('On'),
                   SizedBox(width: 5),
                   Icon(CupertinoIcons.forward)

examples/api/lib/cupertino/nav_bar/cupertino_sliver_nav_bar.0.dart

@@ -86,10 +86,10 @@ class NextPage extends StatelessWidget {
             // when the CupertinoSliverNavigationBar is fully expanded.
             largeTitle: const Text('Family'),
           ),
-          SliverFillRemaining(
+          const SliverFillRemaining(
             child: Column(
               mainAxisAlignment: MainAxisAlignment.spaceEvenly,
-              children: const <Widget>[
+              children: <Widget>[
                 Text('Drag me up', textAlign: TextAlign.center),
                 // When the "leading" parameter is omitted on a route that has a previous page,
                 // the back button is automatically added to the leading position.

examples/api/lib/material/button_style/button_style.0.dart

@@ -30,10 +30,10 @@ class ButtonTypesExample extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return Padding(
-      padding: const EdgeInsets.all(4.0),
+    return const Padding(
+      padding: EdgeInsets.all(4.0),
       child: Row(
-        children: const <Widget>[
+        children: <Widget>[
           Spacer(),
           ButtonTypesGroup(enabled: true),
           ButtonTypesGroup(enabled: false),

examples/api/lib/material/card/card.2.dart

@@ -17,8 +17,8 @@ class CardExamplesApp extends StatelessWidget {
       theme: ThemeData(colorSchemeSeed: const Color(0xff6750a4), useMaterial3: true),
       home: Scaffold(
         appBar: AppBar(title: const Text('Card Examples')),
-        body: Column(
-          children: const <Widget>[
+        body: const Column(
+          children: <Widget>[
             Spacer(),
             ElevatedCardExample(),
             FilledCardExample(),

examples/api/lib/material/divider/divider.1.dart

@@ -28,11 +28,11 @@ class DividerExample extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return Center(
+    return const Center(
       child: Padding(
-        padding: const EdgeInsets.all(16.0),
+        padding: EdgeInsets.all(16.0),
         child: Column(
-          children: const <Widget>[
+          children: <Widget>[
             Expanded(
               child: Card(
                 child: SizedBox.expand(),

examples/api/lib/material/divider/vertical_divider.1.dart

@@ -28,11 +28,11 @@ class DividerExample extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return Center(
+    return const Center(
       child: Padding(
-        padding: const EdgeInsets.all(16.0),
+        padding: EdgeInsets.all(16.0),
         child: Row(
-          children: const <Widget>[
+          children: <Widget>[
             Expanded(
               child: Card(
                 child: SizedBox.expand(),

examples/api/lib/material/icon_button/icon_button.2.dart

@@ -30,10 +30,10 @@ class ButtonTypesExample extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return Padding(
-      padding: const EdgeInsets.all(4.0),
+    return const Padding(
+      padding: EdgeInsets.all(4.0),
       child: Row(
-        children: const <Widget>[
+        children: <Widget>[
           Spacer(),
           ButtonTypesGroup(enabled: true),
           ButtonTypesGroup(enabled: false),

examples/api/lib/material/icon_button/icon_button.3.dart

@@ -38,15 +38,15 @@ class DemoIconToggleButtons extends StatefulWidget {
 class _DemoIconToggleButtonsState extends State<DemoIconToggleButtons> {
   @override
   Widget build(BuildContext context) {
-    return Padding(
-      padding: const EdgeInsets.all(8.0),
+    return const Padding(
+      padding: EdgeInsets.all(8.0),
       child: Column(
         mainAxisAlignment: MainAxisAlignment.spaceEvenly,
         children: <Widget>[
           Row(
             mainAxisAlignment: MainAxisAlignment.center,
             // Standard IconButton
-            children: const <Widget>[
+            children: <Widget>[
               DemoIconToggleButton(isEnabled: true),
               SizedBox(width: 10),
               DemoIconToggleButton(isEnabled: false),
@@ -54,7 +54,7 @@ class _DemoIconToggleButtonsState extends State<DemoIconToggleButtons> {
           ),
           Row(
             mainAxisAlignment: MainAxisAlignment.center,
-            children: const <Widget>[
+            children: <Widget>[
               // Filled IconButton
               DemoIconToggleButton(isEnabled: true, getDefaultStyle: enabledFilledButtonStyle,),
               SizedBox(width: 10),
@@ -63,7 +63,7 @@ class _DemoIconToggleButtonsState extends State<DemoIconToggleButtons> {
           ),
           Row(
             mainAxisAlignment: MainAxisAlignment.center,
-            children: const <Widget>[
+            children: <Widget>[
               // Filled Tonal IconButton
               DemoIconToggleButton(isEnabled: true, getDefaultStyle: enabledFilledTonalButtonStyle,),
               SizedBox(width: 10),
@@ -72,7 +72,7 @@ class _DemoIconToggleButtonsState extends State<DemoIconToggleButtons> {
           ),
           Row(
             mainAxisAlignment: MainAxisAlignment.center,
-            children: const <Widget>[
+            children: <Widget>[
               // Outlined IconButton
               DemoIconToggleButton(isEnabled: true, getDefaultStyle: enabledOutlinedButtonStyle,),
               SizedBox(width: 10),

examples/api/lib/material/input_decorator/input_decoration.prefix_icon_constraints.0.dart

@@ -30,11 +30,11 @@ class MyStatelessWidget extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return Padding(
-      padding: const EdgeInsets.symmetric(horizontal: 8.0),
+    return const Padding(
+      padding: EdgeInsets.symmetric(horizontal: 8.0),
       child: Column(
         mainAxisAlignment: MainAxisAlignment.center,
-        children: const <Widget>[
+        children: <Widget>[
           TextField(
             decoration: InputDecoration(
               hintText: 'Normal Icon Constraints',

examples/api/lib/material/input_decorator/input_decoration.suffix_icon_constraints.0.dart

@@ -30,11 +30,11 @@ class MyStatelessWidget extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return Padding(
-      padding: const EdgeInsets.symmetric(horizontal: 8.0),
+    return const Padding(
+      padding: EdgeInsets.symmetric(horizontal: 8.0),
       child: Column(
         mainAxisAlignment: MainAxisAlignment.center,
-        children: const <Widget>[
+        children: <Widget>[
           TextField(
             decoration: InputDecoration(
               hintText: 'Normal Icon Constraints',

examples/api/lib/material/segmented_button/segmented_button.0.dart

@@ -17,11 +17,11 @@ class SegmentedButtonApp extends StatelessWidget {
   Widget build(BuildContext context) {
     return MaterialApp(
       theme: ThemeData(useMaterial3: true),
-      home: Scaffold(
+      home: const Scaffold(
         body: Center(
           child: Column(
             mainAxisAlignment: MainAxisAlignment.center,
-            children: const <Widget>[
+            children: <Widget>[
               Spacer(),
               Text('Single choice'),
               SingleChoice(),

examples/api/lib/material/selectable_region/selectable_region.0.dart

@@ -21,10 +21,10 @@ class MyApp extends StatelessWidget {
       home: SelectionArea(
         child: Scaffold(
           appBar: AppBar(title: const Text(_title)),
-          body: Center(
+          body: const Center(
             child: Column(
               mainAxisAlignment: MainAxisAlignment.center,
-              children: const <Widget>[
+              children: <Widget>[
                 Text('Select this icon', style: TextStyle(fontSize: 30)),
                 SizedBox(height: 10),
                 MySelectableAdapter(child: Icon(Icons.key, size: 30)),

examples/api/lib/material/selection_area/selection_area.0.dart

@@ -20,10 +20,10 @@ class MyApp extends StatelessWidget {
       home: SelectionArea(
         child: Scaffold(
           appBar: AppBar(title: const Text(_title)),
-          body: Center(
+          body: const Center(
             child: Column(
               mainAxisAlignment: MainAxisAlignment.center,
-              children: const <Widget>[
+              children: <Widget>[
                 Text('Row 1'),
                 Text('Row 2'),
                 Text('Row 3'),

examples/api/lib/material/selection_container/selection_container.0.dart

@@ -21,11 +21,11 @@ class MyApp extends StatelessWidget {
       home: SelectionArea(
         child: Scaffold(
           appBar: AppBar(title: const Text(_title)),
-          body: Center(
+          body: const Center(
             child: SelectionAllOrNoneContainer(
               child: Column(
                 mainAxisAlignment: MainAxisAlignment.center,
-                children: const <Widget>[
+                children: <Widget>[
                   Text('Row 1'),
                   Text('Row 2'),
                   Text('Row 3'),

examples/api/lib/material/selection_container/selection_container_disabled.0.dart

@@ -19,11 +19,11 @@ class MyApp extends StatelessWidget {
       title: _title,
       home: Scaffold(
         appBar: AppBar(title: const Text(_title)),
-        body: Center(
+        body: const Center(
           child: SelectionArea(
             child: Column(
               mainAxisAlignment: MainAxisAlignment.center,
-              children: const <Widget>[
+              children: <Widget>[
                 Text('Selectable text'),
                 SelectionContainer.disabled(child: Text('Non-selectable text')),
                 Text('Selectable text'),

examples/api/lib/material/text_field/text_field.2.dart

@@ -17,8 +17,8 @@ class TextFieldExamplesApp extends StatelessWidget {
       theme: ThemeData(colorSchemeSeed: const Color(0xff6750a4), useMaterial3: true),
       home: Scaffold(
         appBar: AppBar(title: const Text('TextField Examples')),
-        body: Column(
-          children: const <Widget>[
+        body: const Column(
+          children: <Widget>[
             Spacer(),
             FilledTextFieldExample(),
             OutlinedTextFieldExample(),

examples/api/lib/widgets/actions/action.action_overridable.0.dart

@@ -64,14 +64,14 @@ class VerificationCodeGenerator extends StatelessWidget {
   Widget build(BuildContext context) {
     return Actions(
       actions: <Type, Action<Intent>> { CopyTextIntent: CallbackAction<CopyTextIntent>(onInvoke: _copy) },
-      child: Column(
+      child: const Column(
         mainAxisAlignment: MainAxisAlignment.center,
         children: <Widget>[
-          const Text('Press Ctrl-C to Copy'),
-          const SizedBox(height: 10),
+          Text('Press Ctrl-C to Copy'),
+          SizedBox(height: 10),
           Row(
             mainAxisAlignment: MainAxisAlignment.center,
-            children: const <Widget>[
+            children: <Widget>[
               CopyableText(text: '111'),
               SizedBox(width: 5,),
               CopyableText(text: '222'),

examples/api/lib/widgets/focus_traversal/ordered_traversal_policy.0.dart

@@ -64,25 +64,25 @@ class MyStatelessWidget extends StatelessWidget {
   Widget build(BuildContext context) {
     return FocusTraversalGroup(
       policy: OrderedTraversalPolicy(),
-      child: Column(
+      child: const Column(
         mainAxisAlignment: MainAxisAlignment.center,
         children: <Widget>[
           Row(
             mainAxisAlignment: MainAxisAlignment.center,
-            children: const <Widget>[
+            children: <Widget>[
               DemoButton(name: 'Six', order: 6),
             ],
           ),
           Row(
             mainAxisAlignment: MainAxisAlignment.center,
-            children: const <Widget>[
+            children: <Widget>[
               DemoButton(name: 'Five', order: 5),
               DemoButton(name: 'Four', order: 4),
             ],
           ),
           Row(
             mainAxisAlignment: MainAxisAlignment.center,
-            children: const <Widget>[
+            children: <Widget>[
               DemoButton(name: 'Three', order: 3),
               DemoButton(name: 'Two', order: 2),
               DemoButton(name: 'One', order: 1, autofocus: true),

examples/api/lib/widgets/inherited_notifier/inherited_notifier.0.dart

@@ -90,9 +90,9 @@ class _MyStatefulWidgetState extends State<MyStatefulWidget>
   Widget build(BuildContext context) {
     return SpinModel(
       notifier: _controller,
-      child: Row(
+      child: const Row(
         mainAxisAlignment: MainAxisAlignment.spaceAround,
-        children: const <Widget>[
+        children: <Widget>[
           Spinner(),
           Spinner(),
           Spinner(),

examples/api/lib/widgets/overlay/overlay.0.dart

@@ -61,8 +61,8 @@ class _OverlayExampleState extends State<OverlayExample> {
                   Builder(builder: (BuildContext context) {
                     switch (currentPageIndex) {
                       case 0:
-                        return Column(
-                          children: const <Widget>[
+                        return const Column(
+                          children: <Widget>[
                             Text(
                               'Explore page',
                                 style: TextStyle(
@@ -76,8 +76,8 @@ class _OverlayExampleState extends State<OverlayExample> {
                           ],
                         );
                       case 1:
-                        return Column(
-                          children: const <Widget>[
+                        return const Column(
+                          children: <Widget>[
                             Text(
                               'Commute page',
                                 style: TextStyle(
@@ -91,8 +91,8 @@ class _OverlayExampleState extends State<OverlayExample> {
                           ],
                         );
                       case 2:
-                        return Column(
-                          children: const <Widget>[
+                        return const Column(
+                          children: <Widget>[
                             Text(
                               'Saved page',
                                 style: TextStyle(

examples/api/lib/widgets/shortcuts/character_activator.0.dart

@@ -56,10 +56,10 @@ class _MyStatefulWidgetState extends State<MyStatefulWidget> {
             },
           ),
         },
-        child: Focus(
+        child: const Focus(
           autofocus: true,
           child: Column(
-            children: const <Widget>[
+            children: <Widget>[
               Text('Press question mark for help'),
             ],
           ),

examples/api/lib/widgets/transitions/listenable_builder.0.dart

@@ -152,9 +152,9 @@ class ListenableBuilderExample extends StatelessWidget {
                     // The container background will change color to this when
                     // the subtree has focus.
                     focusedColor: Colors.blue.shade50,
-                    child: Column(
+                    child: const Column(
                       crossAxisAlignment: CrossAxisAlignment.start,
-                      children: const <Widget>[
+                      children: <Widget>[
                         Text('Owner:'),
                         MyField(label: 'First Name'),
                         MyField(label: 'Last Name'),

examples/splash/lib/main.dart

@@ -6,13 +6,13 @@ import 'package:flutter/material.dart';
 
 void main() {
   runApp(
-    DecoratedBox(
-      decoration: const BoxDecoration(color: Colors.white),
+    const DecoratedBox(
+      decoration: BoxDecoration(color: Colors.white),
       child: Center(
         child: Column(
           mainAxisAlignment: MainAxisAlignment.center,
           textDirection: TextDirection.ltr,
-          children: const <Widget>[
+          children: <Widget>[
             FlutterLogo(size: 48),
             Padding(
               padding: EdgeInsets.all(32),

packages/flutter/lib/src/cupertino/icons.dart

@@ -30,9 +30,9 @@ import 'package:flutter/widgets.dart';
 /// ![The following code snippet would generate a row of icons consisting of a pink heart, a green bell, and a blue umbrella, each progressively bigger than the last.](https://flutter.github.io/assets-for-api-docs/assets/cupertino/cupertino_icon.png)
 ///
 /// ```dart
-/// Row(
+/// const Row(
 ///   mainAxisAlignment: MainAxisAlignment.spaceAround,
-///   children: const <Widget>[
+///   children: <Widget>[
 ///     Icon(
 ///       CupertinoIcons.heart_fill,
 ///       color: Colors.pink,

packages/flutter/lib/src/material/button_bar.dart

@@ -233,7 +233,7 @@ class ButtonBar extends StatelessWidget {
 class _ButtonBarRow extends Flex {
   /// Creates a button bar that attempts to display in a row, but displays in
   /// a column if there is insufficient horizontal space.
-  _ButtonBarRow({
+  const _ButtonBarRow({
     required super.children,
     super.mainAxisSize,
     super.mainAxisAlignment,

packages/flutter/lib/src/material/icons.dart

@@ -119,9 +119,9 @@ class PlatformAdaptiveIcons implements Icons {
 /// ![The following code snippet would generate a row of icons consisting of a pink heart, a green musical note, and a blue umbrella, each progressively bigger than the last.](https://flutter.github.io/assets-for-api-docs/assets/widgets/icon.png)
 ///
 /// ```dart
-/// Row(
+/// const Row(
 ///   mainAxisAlignment: MainAxisAlignment.spaceAround,
-///   children: const <Widget>[
+///   children: <Widget>[
 ///     Icon(
 ///       Icons.favorite,
 ///       color: Colors.pink,

packages/flutter/lib/src/material/list_tile.dart

@@ -160,8 +160,8 @@ enum ListTileControlAffinity {
 /// whereas a [Row] does not constrain its children.
 ///
 /// ```dart
-/// Row(
-///   children: const <Widget>[
+/// const Row(
+///   children: <Widget>[
 ///     Expanded(
 ///       child: ListTile(
 ///         leading: FlutterLogo(),

packages/flutter/lib/src/material/tabs.dart

@@ -275,7 +275,7 @@ class _TabLabelBarRenderer extends RenderFlex {
 // upon layout. The tab widths are only used at paint time (see _IndicatorPainter)
 // or in response to input.
 class _TabLabelBar extends Flex {
-  _TabLabelBar({
+  const _TabLabelBar({
     super.children,
     required this.onPerformLayout,
   }) : super(

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

@@ -4445,9 +4445,7 @@ class Flex extends MultiChildRenderObjectWidget {
   /// to be necessary to decide which direction to lay the children in or to
   /// disambiguate `start` or `end` values for the main or cross axis
   /// directions, the [textDirection] must not be null.
-  // TODO(goderbauer): Figure out whether this can be const.
-  // ignore: prefer_const_constructors_in_immutables
-  Flex({
+  const Flex({
     super.key,
     required this.direction,
     this.mainAxisAlignment = MainAxisAlignment.start,
@@ -4458,7 +4456,8 @@ class Flex extends MultiChildRenderObjectWidget {
     this.textBaseline, // NO DEFAULT: we don't know what the text's baseline should be
     this.clipBehavior = Clip.none,
     super.children,
-  }) : assert(crossAxisAlignment != CrossAxisAlignment.baseline || textBaseline != null, 'textBaseline is required if you specify the crossAxisAlignment with CrossAxisAlignment.baseline');
+  }) : assert(!identical(crossAxisAlignment, CrossAxisAlignment.baseline) || textBaseline != null, 'textBaseline is required if you specify the crossAxisAlignment with CrossAxisAlignment.baseline');
+  // Cannot use == in the assert above instead of identical because of https://github.com/dart-lang/language/issues/1811.
 
   /// The direction to use as the main axis.
   ///
@@ -4649,8 +4648,8 @@ class Flex extends MultiChildRenderObjectWidget {
 /// ![](https://flutter.github.io/assets-for-api-docs/assets/widgets/row.png)
 ///
 /// ```dart
-/// Row(
-///   children: const <Widget>[
+/// const Row(
+///   children: <Widget>[
 ///     Expanded(
 ///       child: Text('Deliver features faster', textAlign: TextAlign.center),
 ///     ),
@@ -4684,8 +4683,8 @@ class Flex extends MultiChildRenderObjectWidget {
 /// Suppose, for instance, that you had this code:
 ///
 /// ```dart
-/// Row(
-///   children: const <Widget>[
+/// const Row(
+///   children: <Widget>[
 ///     FlutterLogo(),
 ///     Text("Flutter's hot reload helps you quickly and easily experiment, build UIs, add features, and fix bug faster. Experience sub-second reload times, without losing state, on emulators, simulators, and hardware for iOS and Android."),
 ///     Icon(Icons.sentiment_very_satisfied),
@@ -4711,8 +4710,8 @@ class Flex extends MultiChildRenderObjectWidget {
 /// row that the child should be given the remaining room:
 ///
 /// ```dart
-/// Row(
-///   children: const <Widget>[
+/// const Row(
+///   children: <Widget>[
 ///     FlutterLogo(),
 ///     Expanded(
 ///       child: Text("Flutter's hot reload helps you quickly and easily experiment, build UIs, add features, and fix bug faster. Experience sub-second reload times, without losing state, on emulators, simulators, and hardware for iOS and Android."),
@@ -4740,9 +4739,9 @@ class Flex extends MultiChildRenderObjectWidget {
 /// [TextDirection.rtl]. This is shown in the example below
 ///
 /// ```dart
-/// Row(
+/// const Row(
 ///   textDirection: TextDirection.rtl,
-///   children: const <Widget>[
+///   children: <Widget>[
 ///     FlutterLogo(),
 ///     Expanded(
 ///       child: Text("Flutter's hot reload helps you quickly and easily experiment, build UIs, add features, and fix bug faster. Experience sub-second reload times, without losing state, on emulators, simulators, and hardware for iOS and Android."),
@@ -4814,7 +4813,7 @@ class Row extends Flex {
   /// unless the row has no children or only one child) or to disambiguate
   /// `start` or `end` values for the [mainAxisAlignment], the [textDirection]
   /// must not be null.
-  Row({
+  const Row({
     super.key,
     super.mainAxisAlignment,
     super.mainAxisSize,
@@ -4851,8 +4850,8 @@ class Row extends Flex {
 /// ![Using the Column in this way creates two short lines of text with a large Flutter underneath.](https://flutter.github.io/assets-for-api-docs/assets/widgets/column.png)
 ///
 /// ```dart
-/// Column(
-///   children: const <Widget>[
+/// const Column(
+///   children: <Widget>[
 ///     Text('Deliver features faster'),
 ///     Text('Craft beautiful UIs'),
 ///     Expanded(
@@ -5007,7 +5006,7 @@ class Column extends Flex {
   /// any. If there is no ambient directionality, and a text direction is going
   /// to be necessary to disambiguate `start` or `end` values for the
   /// [crossAxisAlignment], the [textDirection] must not be null.
-  Column({
+  const Column({
     super.key,
     super.mainAxisAlignment,
     super.mainAxisSize,

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

@@ -37,15 +37,15 @@ import 'text_editing_intents.dart';
 ///   // If using WidgetsApp or its descendents MaterialApp or CupertinoApp,
 ///   // then DefaultTextEditingShortcuts is already being inserted into the
 ///   // widget tree.
-///   return DefaultTextEditingShortcuts(
+///   return const DefaultTextEditingShortcuts(
 ///     child: Center(
 ///       child: Shortcuts(
-///         shortcuts: const <ShortcutActivator, Intent>{
+///         shortcuts: <ShortcutActivator, Intent>{
 ///           SingleActivator(LogicalKeyboardKey.arrowDown, alt: true): NextFocusIntent(),
 ///           SingleActivator(LogicalKeyboardKey.arrowUp, alt: true): PreviousFocusIntent(),
 ///         },
 ///         child: Column(
-///           children: const <Widget>[
+///           children: <Widget>[
 ///             TextField(
 ///               decoration: InputDecoration(
 ///                 hintText: 'alt + down moves to the next field.',

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

@@ -36,9 +36,9 @@ import 'icon_theme_data.dart';
 /// ![The following code snippet would generate a row of icons consisting of a pink heart, a green musical note, and a blue umbrella, each progressively bigger than the last.](https://flutter.github.io/assets-for-api-docs/assets/widgets/icon.png)
 ///
 /// ```dart
-/// Row(
+/// const Row(
 ///   mainAxisAlignment: MainAxisAlignment.spaceAround,
-///   children: const <Widget>[
+///   children: <Widget>[
 ///     Icon(
 ///       Icons.favorite,
 ///       color: Colors.pink,

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

@@ -18,8 +18,8 @@ import 'framework.dart';
 /// {@tool snippet}
 ///
 /// ```dart
-/// Row(
-///   children: const <Widget>[
+/// const Row(
+///   children: <Widget>[
 ///     Text('Begin'),
 ///     Spacer(), // Defaults to a flex of one.
 ///     Text('Middle'),

packages/flutter/test/cupertino/text_field_test.dart

@@ -1702,9 +1702,9 @@ void main() {
 
   testWidgets('copy paste', (WidgetTester tester) async {
     await tester.pumpWidget(
-      CupertinoApp(
+      const CupertinoApp(
         home: Column(
-          children: const <Widget>[
+          children: <Widget>[
             CupertinoTextField(
               placeholder: 'field 1',
             ),

packages/flutter/test/material/app_bar_test.dart

@@ -701,7 +701,7 @@ void main() {
           appBar: AppBar(
             title: const Text('X'),
           ),
-          drawer: Column(), // Doesn't really matter. Triggers a hamburger regardless.
+          drawer: const Column(), // Doesn't really matter. Triggers a hamburger regardless.
         ),
       ),
     );

packages/flutter/test/material/bottom_app_bar_theme_test.dart

@@ -253,9 +253,9 @@ Widget _withTheme(BottomAppBarTheme theme, [bool useMaterial3 = false]) {
       floatingActionButtonLocation: FloatingActionButtonLocation.centerDocked,
       bottomNavigationBar: RepaintBoundary(
         key: _painterKey,
-        child: BottomAppBar(
+        child: const BottomAppBar(
           child: Row(
-            children: const <Widget>[
+            children: <Widget>[
               Icon(Icons.add),
               Expanded(child: SizedBox()),
               Icon(Icons.add),

packages/flutter/test/material/card_test.dart

@@ -82,13 +82,13 @@ void main() {
     debugResetSemanticsIdCounter();
 
     await tester.pumpWidget(
-      Directionality(
+      const Directionality(
         textDirection: TextDirection.ltr,
         child: Material(
           child: Center(
             child: Card(
               child: Column(
-                children: const <Widget>[
+                children: <Widget>[
                   Text('First child'),
                   Text('Second child'),
                 ],

packages/flutter/test/material/chip_test.dart

@@ -579,8 +579,8 @@ void main() {
     const TextStyle style = TextStyle(fontFamily: 'Ahem', fontSize: 10.0);
     await tester.pumpWidget(
       wrapForChip(
-        child: Row(
-          children: const <Widget>[
+        child: const Row(
+          children: <Widget>[
             Chip(label: Text('Test'), labelStyle: style),
           ],
         ),
@@ -590,8 +590,8 @@ void main() {
     expect(tester.getSize(find.byType(Chip)), const Size(64.0, 48.0));
     await tester.pumpWidget(
       wrapForChip(
-        child: Row(
-          children: const <Widget>[
+        child: const Row(
+          children: <Widget>[
             Flexible(child: Chip(label: Text('Test'), labelStyle: style)),
           ],
         ),
@@ -601,8 +601,8 @@ void main() {
     expect(tester.getSize(find.byType(Chip)), const Size(64.0, 48.0));
     await tester.pumpWidget(
       wrapForChip(
-        child: Row(
-          children: const <Widget>[
+        child: const Row(
+          children: <Widget>[
             Expanded(child: Chip(label: Text('Test'), labelStyle: style)),
           ],
         ),
@@ -615,8 +615,8 @@ void main() {
   testWidgets('Chip responds to materialTapTargetSize', (WidgetTester tester) async {
       await tester.pumpWidget(
         wrapForChip(
-          child: Column(
-            children: const <Widget>[
+          child: const Column(
+            children: <Widget>[
               Chip(
                 label: Text('X'),
                 materialTapTargetSize: MaterialTapTargetSize.padded,
@@ -731,8 +731,8 @@ void main() {
   testWidgets('Chip responds to textScaleFactor', (WidgetTester tester) async {
     await tester.pumpWidget(
       wrapForChip(
-        child: Column(
-          children: const <Widget>[
+        child: const Column(
+          children: <Widget>[
             Chip(
               avatar: CircleAvatar(child: Text('A')),
               label: Text('Chip A'),
@@ -762,8 +762,8 @@ void main() {
     await tester.pumpWidget(
       wrapForChip(
         textScaleFactor: 3.0,
-        child: Column(
-          children: const <Widget>[
+        child: const Column(
+          children: <Widget>[
             Chip(
               avatar: CircleAvatar(child: Text('A')),
               label: Text('Chip A'),
@@ -789,8 +789,8 @@ void main() {
     // Check that individual text scales are taken into account.
     await tester.pumpWidget(
       wrapForChip(
-        child: Column(
-          children: const <Widget>[
+        child: const Column(
+          children: <Widget>[
             Chip(
               avatar: CircleAvatar(child: Text('A')),
               label: Text('Chip A', textScaleFactor: 3.0),

packages/flutter/test/material/divider_test.dart

@@ -128,12 +128,12 @@ void main() {
 
   testWidgets('Vertical Divider Test 2', (WidgetTester tester) async {
     await tester.pumpWidget(
-      MaterialApp(
+      const MaterialApp(
         home: Material(
           child: SizedBox(
             height: 24.0,
             child: Row(
-              children: const <Widget>[
+              children: <Widget>[
                 Text('Hey.'),
                 VerticalDivider(),
               ],

packages/flutter/test/material/expansion_tile_test.dart

@@ -238,10 +238,10 @@ void main() {
           platform: TargetPlatform.iOS,
           dividerColor: dividerColor,
         ),
-        home: Material(
+        home: const Material(
           child: SingleChildScrollView(
             child: Column(
-              children: const <Widget>[
+              children: <Widget>[
                 ExpansionTile(
                   title: Text('Tile 1'),
                   maintainState: true,

packages/flutter/test/material/floating_action_button_location_test.dart

@@ -317,8 +317,8 @@ void main() {
           appBar: AppBar(),
           floatingActionButton: FloatingActionButton(onPressed: () { }, mini: true),
           floatingActionButtonLocation: FloatingActionButtonLocation.miniStartTop,
-          body: Column(
-            children: const <Widget>[
+          body: const Column(
+            children: <Widget>[
               ListTile(
                 leading: CircleAvatar(),
               ),

packages/flutter/test/material/input_decorator_test.dart

@@ -5935,12 +5935,12 @@ void main() {
 
   testWidgets('min intrinsic height for TextField with no content padding', (WidgetTester tester) async {
     // Regression test for: https://github.com/flutter/flutter/issues/75509
-    await tester.pumpWidget(MaterialApp(
+    await tester.pumpWidget(const MaterialApp(
       home: Material(
         child: Center(
           child: IntrinsicHeight(
             child: Column(
-              children: const <Widget>[
+              children: <Widget>[
                 TextField(
                   decoration: InputDecoration(
                     labelText: 'Label Text',

packages/flutter/test/material/raw_material_button_test.dart

@@ -240,12 +240,12 @@ void main() {
             RawMaterialButton(
               materialTapTargetSize: MaterialTapTargetSize.padded,
               onPressed: () { },
-              child: SizedBox(
+              child: const SizedBox(
                 width: 400.0,
                 height: 400.0,
                 child: Column(
                   mainAxisAlignment: MainAxisAlignment.end,
-                  children: const <Widget>[
+                  children: <Widget>[
                     SizedBox(
                       height: 50.0,
                       width: 400.0,

packages/flutter/test/material/tabs_test.dart

@@ -4515,10 +4515,10 @@ void main() {
 
   testWidgets('Tab preferredSize gives correct value', (WidgetTester tester) async {
     await tester.pumpWidget(
-      MaterialApp(
+      const MaterialApp(
         home: Material(
           child: Row(
-            children: const <Tab>[
+            children: <Tab>[
               Tab(icon: Icon(Icons.message)),
               Tab(text: 'Two'),
               Tab(text: 'Three', icon: Icon(Icons.chat)),

packages/flutter/test/material/toggle_buttons_test.dart

@@ -389,8 +389,8 @@ void main() {
             child: ToggleButtons(
               isSelected: const <bool>[false],
               onPressed: (int index) {},
-              children: <Widget>[
-                Row(children: const <Widget>[
+              children: const <Widget>[
+                Row(children: <Widget>[
                   Text('First child'),
                   Icon(Icons.check),
                 ]),
@@ -416,8 +416,8 @@ void main() {
             child: ToggleButtons(
               isSelected: const <bool>[true],
               onPressed: (int index) {},
-              children: <Widget>[
-                Row(children: const <Widget>[
+              children: const <Widget>[
+                Row(children: <Widget>[
                   Text('First child'),
                   Icon(Icons.check),
                 ]),
@@ -442,8 +442,8 @@ void main() {
           child: boilerplate(
             child: ToggleButtons(
               isSelected: const <bool>[true],
-              children: <Widget>[
-                Row(children: const <Widget>[
+              children: const <Widget>[
+                Row(children: <Widget>[
                   Text('First child'),
                   Icon(Icons.check),
                 ]),
@@ -497,8 +497,8 @@ void main() {
               color: enabledColor,
               isSelected: const <bool>[false],
               onPressed: (int index) {},
-              children: <Widget>[
-                Row(children: const <Widget>[
+              children: const <Widget>[
+                Row(children: <Widget>[
                   Text('First child'),
                   Icon(Icons.check),
                 ]),
@@ -519,8 +519,8 @@ void main() {
               selectedColor: selectedColor,
               isSelected: const <bool>[true],
               onPressed: (int index) {},
-              children: <Widget>[
-                Row(children: const <Widget>[
+              children: const <Widget>[
+                Row(children: <Widget>[
                   Text('First child'),
                   Icon(Icons.check),
                 ]),
@@ -540,8 +540,8 @@ void main() {
             child: ToggleButtons(
               disabledColor: disabledColor,
               isSelected: const <bool>[true],
-              children: <Widget>[
-                Row(children: const <Widget>[
+              children: const <Widget>[
+                Row(children: <Widget>[
                   Text('First child'),
                   Icon(Icons.check),
                 ]),
@@ -565,8 +565,8 @@ void main() {
           child: ToggleButtons(
             isSelected: const <bool>[false],
             onPressed: (int index) {},
-            children: <Widget>[
-              Row(children: const <Widget>[
+            children: const <Widget>[
+              Row(children: <Widget>[
                 Text('First child'),
               ]),
             ],
@@ -594,8 +594,8 @@ void main() {
           child: ToggleButtons(
             isSelected: const <bool>[true],
             onPressed: (int index) {},
-            children: <Widget>[
-              Row(children: const <Widget>[
+            children: const <Widget>[
+              Row(children: <Widget>[
                 Text('First child'),
               ]),
             ],
@@ -622,8 +622,8 @@ void main() {
         child: boilerplate(
           child: ToggleButtons(
             isSelected: const <bool>[true],
-            children: <Widget>[
-              Row(children: const <Widget>[
+            children: const <Widget>[
+              Row(children: <Widget>[
                 Text('First child'),
               ]),
             ],
@@ -652,8 +652,8 @@ void main() {
             fillColor: customFillColor,
             isSelected: const <bool>[true],
             onPressed: (int index) {},
-            children: <Widget>[
-              Row(children: const <Widget>[
+            children: const <Widget>[
+              Row(children: <Widget>[
                 Text('First child'),
               ]),
             ],

packages/flutter/test/material/toggle_buttons_theme_test.dart

@@ -261,10 +261,10 @@ void main() {
                 color: enabledColor,
                 isSelected: const <bool>[false],
                 onPressed: (int index) {},
-                children: <Widget>[
+                children: const <Widget>[
                   // This Row is used like this to test for both TextStyle
                   // and IconTheme for Text and Icon widgets respectively.
-                  Row(children: const <Widget>[
+                  Row(children: <Widget>[
                     Text('First child'),
                     Icon(Icons.check),
                   ]),
@@ -290,8 +290,8 @@ void main() {
                 color: enabledColor,
                 isSelected: const <bool>[true],
                 onPressed: (int index) {},
-                children: <Widget>[
-                  Row(children: const <Widget>[
+                children: const <Widget>[
+                  Row(children: <Widget>[
                     Text('First child'),
                     Icon(Icons.check),
                   ]),
@@ -317,8 +317,8 @@ void main() {
               child: ToggleButtons(
                 color: enabledColor,
                 isSelected: const <bool>[false],
-                children: <Widget>[
-                  Row(children: const <Widget>[
+                children: const <Widget>[
+                  Row(children: <Widget>[
                     Text('First child'),
                     Icon(Icons.check),
                   ]),
@@ -346,8 +346,8 @@ void main() {
             child: ToggleButtons(
               isSelected: const <bool>[true],
               onPressed: (int index) {},
-              children: <Widget>[
-                Row(children: const <Widget>[
+              children: const <Widget>[
+                Row(children: <Widget>[
                   Text('First child'),
                 ]),
               ],

packages/flutter/test/material/tooltip_test.dart

@@ -1280,10 +1280,10 @@ void main() {
     await gesture.moveTo(Offset.zero);
 
     await tester.pumpWidget(
-      MaterialApp(
+      const MaterialApp(
         home: Center(
           child: Column(
-            children: const <Widget>[
+            children: <Widget>[
               Tooltip(
                 message: 'message1',
                 waitDuration: waitDuration,

packages/flutter/test/rendering/flex_overflow_test.dart

@@ -10,9 +10,9 @@ import 'mock_canvas.dart';
 void main() {
   testWidgets('Flex overflow indicator', (WidgetTester tester) async {
     await tester.pumpWidget(
-      Center(
+      const Center(
         child: Column(
-          children: const <Widget>[
+          children: <Widget>[
             SizedBox(width: 200.0, height: 200.0),
           ],
         ),
@@ -22,11 +22,11 @@ void main() {
     expect(find.byType(Column), isNot(paints..rect()));
 
     await tester.pumpWidget(
-      Center(
+      const Center(
         child: SizedBox(
           height: 100.0,
           child: Column(
-            children: const <Widget>[
+            children: <Widget>[
               SizedBox(width: 200.0, height: 200.0),
             ],
           ),
@@ -39,11 +39,11 @@ void main() {
     expect(find.byType(Column), paints..rect());
 
     await tester.pumpWidget(
-      Center(
+      const Center(
         child: SizedBox(
           height: 0.0,
           child: Column(
-            children: const <Widget>[
+            children: <Widget>[
               SizedBox(width: 200.0, height: 200.0),
             ],
           ),

packages/flutter/test/rendering/view_chrome_style_test.dart

@@ -232,7 +232,7 @@ void main() {
     testWidgets('Top AnnotatedRegion provides status bar overlay style and bottom AnnotatedRegion provides navigation bar overlay style', (WidgetTester tester) async {
       setupTestDevice();
       await tester.pumpWidget(
-        Column(children: const <Widget>[
+        const Column(children: <Widget>[
           Expanded(child: AnnotatedRegion<SystemUiOverlayStyle>(
             value: SystemUiOverlayStyle(
               systemNavigationBarColor: Colors.blue,
@@ -258,7 +258,7 @@ void main() {
     testWidgets('Top only AnnotatedRegion provides status bar and navigation bar style properties', (WidgetTester tester) async {
       setupTestDevice();
       await tester.pumpWidget(
-        Column(children: const <Widget>[
+        const Column(children: <Widget>[
           Expanded(child: AnnotatedRegion<SystemUiOverlayStyle>(
             value: SystemUiOverlayStyle(
               systemNavigationBarColor: Colors.blue,
@@ -278,7 +278,7 @@ void main() {
     testWidgets('Bottom only AnnotatedRegion provides status bar and navigation bar style properties', (WidgetTester tester) async {
       setupTestDevice();
       await tester.pumpWidget(
-        Column(children: const <Widget>[
+        const Column(children: <Widget>[
           Expanded(child: SizedBox.expand()),
           Expanded(child: AnnotatedRegion<SystemUiOverlayStyle>(
             value: SystemUiOverlayStyle(

packages/flutter/test/semantics/semantics_elevation_test.dart

@@ -26,25 +26,25 @@ void main() {
     //                                                           |
     //                                     --------------------------------------- 'ground'
     final SemanticsTester semantics = SemanticsTester(tester);
-    await tester.pumpWidget(MaterialApp(
+    await tester.pumpWidget(const MaterialApp(
       home: Column(
         children: <Widget>[
-          const Text('ground'),
+          Text('ground'),
           Card(
             elevation: 10.0,
             child: Column(
               children: <Widget>[
-                const Text('absolute elevation: 10'),
+                Text('absolute elevation: 10'),
                 PhysicalModel(
                   elevation: 5.0,
                   color: Colors.black,
                   child: Column(
                     children: <Widget>[
-                      const Text('absolute elevation: 15'),
+                      Text('absolute elevation: 15'),
                       Card(
                         elevation: 7.0,
                         child: Column(
-                          children: const <Widget>[
+                          children: <Widget>[
                             Text('absolute elevation: 22'),
                             Card(
                               elevation: 8.0,
@@ -56,7 +56,7 @@ void main() {
                     ],
                   ),
                 ),
-                const Card(
+                Card(
                   elevation: 15.0,
                   child: Text('absolute elevation: 25'),
                 ),
@@ -102,15 +102,15 @@ void main() {
     // is reversed
 
     final SemanticsTester semantics = SemanticsTester(tester);
-    await tester.pumpWidget(MaterialApp(
+    await tester.pumpWidget(const MaterialApp(
       home: Column(
         children: <Widget>[
-          const Text('ground'),
+          Text('ground'),
           Card(
             elevation: 10.0,
             child: Column(
               children: <Widget>[
-                const Card(
+                Card(
                   elevation: 15.0,
                   child: Text('absolute elevation: 25'),
                 ),
@@ -119,11 +119,11 @@ void main() {
                   color: Colors.black,
                   child: Column(
                     children: <Widget>[
-                      const Text('absolute elevation: 15'),
+                      Text('absolute elevation: 15'),
                       Card(
                         elevation: 7.0,
                         child: Column(
-                          children: const <Widget>[
+                          children: <Widget>[
                             Text('absolute elevation: 22'),
                             Card(
                               elevation: 8.0,
@@ -135,7 +135,7 @@ void main() {
                     ],
                   ),
                 ),
-                const Text('absolute elevation: 10'),
+                Text('absolute elevation: 10'),
               ],
             ),
           ),
@@ -205,8 +205,8 @@ void main() {
               MergeSemantics(
                 child: Semantics(
                   explicitChildNodes: true, // just to be sure that it's going to be an explicit merge
-                  child: Column(
-                    children: const <Widget>[
+                  child: const Column(
+                    children: <Widget>[
                       Card(
                         elevation: 15.0,
                         child: Text('abs. elevation 25.0'),
@@ -259,8 +259,8 @@ void main() {
                 MergeSemantics(
                   child: Semantics(
                     explicitChildNodes: true, // just to be sure that it's going to be an explicit merge
-                    child: Column(
-                      children: const <Widget>[
+                    child: const Column(
+                      children: <Widget>[
                         Card(
                           elevation: 5.0,
                           child: Text('abs. elevation 15.0'),

packages/flutter/test/widgets/align_test.dart

@@ -107,12 +107,12 @@ void main() {
 
   testWidgets('Align widthFactor', (WidgetTester tester) async {
     await tester.pumpWidget(
-      Directionality(
+      const Directionality(
         textDirection: TextDirection.ltr,
         child: Row(
           crossAxisAlignment: CrossAxisAlignment.start,
           mainAxisAlignment: MainAxisAlignment.center,
-          children: const <Widget>[
+          children: <Widget>[
             Align(
               widthFactor: 0.5,
               child: SizedBox(
@@ -130,12 +130,12 @@ void main() {
 
   testWidgets('Align heightFactor', (WidgetTester tester) async {
     await tester.pumpWidget(
-      Directionality(
+      const Directionality(
         textDirection: TextDirection.ltr,
         child: Column(
           mainAxisAlignment: MainAxisAlignment.center,
           crossAxisAlignment: CrossAxisAlignment.start,
-          children: const <Widget>[
+          children: <Widget>[
             Align(
               heightFactor: 0.5,
               child: SizedBox(

packages/flutter/test/widgets/animated_align_test.dart

@@ -59,11 +59,11 @@ void main() {
 
   testWidgets('AnimatedAlign widthFactor', (WidgetTester tester) async {
     await tester.pumpWidget(
-      Directionality(
+      const Directionality(
         textDirection: TextDirection.ltr,
         child: Row(
           mainAxisSize: MainAxisSize.min,
-          children: const <Widget>[
+          children: <Widget>[
             AnimatedAlign(
               alignment: Alignment.center,
               curve: Curves.ease,
@@ -84,10 +84,10 @@ void main() {
 
   testWidgets('AnimatedAlign heightFactor', (WidgetTester tester) async {
     await tester.pumpWidget(
-      Directionality(
+      const Directionality(
         textDirection: TextDirection.ltr,
         child: Column(
-          children: const <Widget>[
+          children: <Widget>[
             AnimatedAlign(
               alignment: Alignment.center,
               curve: Curves.ease,
@@ -108,11 +108,11 @@ void main() {
 
   testWidgets('AnimatedAlign null height factor', (WidgetTester tester) async {
     await tester.pumpWidget(
-      Directionality(
+      const Directionality(
         textDirection: TextDirection.ltr,
         child: Column(
           mainAxisAlignment: MainAxisAlignment.center,
-          children: const <Widget>[
+          children: <Widget>[
             AnimatedAlign(
               alignment: Alignment.center,
               curve: Curves.ease,
@@ -132,13 +132,13 @@ void main() {
 
   testWidgets('AnimatedAlign null widthFactor', (WidgetTester tester) async {
     await tester.pumpWidget(
-      Directionality(
+      const Directionality(
         textDirection: TextDirection.ltr,
         child: SizedBox.shrink(
           child: Row(
             mainAxisSize: MainAxisSize.min,
             mainAxisAlignment: MainAxisAlignment.center,
-            children: const <Widget>[
+            children: <Widget>[
                AnimatedAlign(
                 alignment: Alignment.center,
                 curve: Curves.ease,

packages/flutter/test/widgets/autofill_group_test.dart

@@ -17,7 +17,7 @@ void main() {
     const TextField client2 = TextField(autofillHints: <String>['2']);
 
     await tester.pumpWidget(
-      MaterialApp(
+      const MaterialApp(
         home: Scaffold(
           body: AutofillGroup(
             key: outerKey,
@@ -25,7 +25,7 @@ void main() {
               client1,
               AutofillGroup(
                 key: innerKey,
-                child: Column(children: const <Widget>[client2, TextField(autofillHints: null)]),
+                child: Column(children: <Widget>[client2, TextField(autofillHints: null)]),
               ),
             ]),
           ),
@@ -135,9 +135,9 @@ void main() {
             child: Column(children: <Widget>[
               client1,
               TextField(key: keyClient3, autofillHints: const <String>['3']),
-              AutofillGroup(
+              const AutofillGroup(
                 key: innerKey,
-                child: Column(children: const <Widget>[client2]),
+                child: Column(children: <Widget>[client2]),
               ),
             ]),
           ),

packages/flutter/test/widgets/basic_test.dart

@@ -658,10 +658,10 @@ void main() {
     });
 
     testWidgets('ColoredBox - no size, no child', (WidgetTester tester) async {
-      await tester.pumpWidget(Flex(
+      await tester.pumpWidget(const Flex(
         direction: Axis.horizontal,
         textDirection: TextDirection.ltr,
-        children: const <Widget>[
+        children: <Widget>[
           SizedBox.shrink(
             child: ColoredBox(color: colorToPaint),
           ),
@@ -681,10 +681,10 @@ void main() {
     testWidgets('ColoredBox - no size, child', (WidgetTester tester) async {
       const ValueKey<int> key = ValueKey<int>(0);
       const Widget child = SizedBox.expand(key: key);
-      await tester.pumpWidget(Flex(
+      await tester.pumpWidget(const Flex(
         direction: Axis.horizontal,
         textDirection: TextDirection.ltr,
-        children: const <Widget>[
+        children: <Widget>[
           SizedBox.shrink(
             child: ColoredBox(color: colorToPaint, child: child),
           ),

packages/flutter/test/widgets/column_test.dart

@@ -18,10 +18,10 @@ void main() {
     // Default is MainAxisSize.max so the Column should be as high as the test: 600.
     // Default is MainAxisAlignment.start so children so the children's
     // top edges should be at 0, 100, 500, child2's height should be 400.
-    await tester.pumpWidget(Center(
+    await tester.pumpWidget(const Center(
       child: Column(
         key: columnKey,
-        children: const <Widget>[
+        children: <Widget>[
           SizedBox(key: child0Key, width: 100.0, height: 100.0),
           Expanded(child: SizedBox(key: child1Key, width: 100.0, height: 100.0)),
           SizedBox(key: child2Key, width: 100.0, height: 100.0),
@@ -64,10 +64,10 @@ void main() {
     // Default is MainAxisSize.max so the Column should be as high as the test: 600.
     // Default is MainAxisAlignment.start so children so the children's
     // top edges should be at 0, 100, 200
-    await tester.pumpWidget(Center(
+    await tester.pumpWidget(const Center(
       child: Column(
         key: columnKey,
-        children: const <Widget>[
+        children: <Widget>[
           SizedBox(key: child0Key, width: 100.0, height: 100.0),
           SizedBox(key: child1Key, width: 100.0, height: 100.0),
           SizedBox(key: child2Key, width: 100.0, height: 100.0),
@@ -108,11 +108,11 @@ void main() {
 
     // Default is MainAxisSize.max so the Column should be as high as the test: 600.
     // The 100x100 children's top edges should be at 200, 300
-    await tester.pumpWidget(Center(
+    await tester.pumpWidget(const Center(
       child: Column(
         key: columnKey,
         mainAxisAlignment: MainAxisAlignment.center,
-        children: const <Widget>[
+        children: <Widget>[
           SizedBox(key: child0Key, width: 100.0, height: 100.0),
           SizedBox(key: child1Key, width: 100.0, height: 100.0),
         ],
@@ -147,11 +147,11 @@ void main() {
 
     // Default is MainAxisSize.max so the Column should be as high as the test: 600.
     // The 100x100 children's top edges should be at 300, 400, 500.
-    await tester.pumpWidget(Center(
+    await tester.pumpWidget(const Center(
       child: Column(
         key: columnKey,
         mainAxisAlignment: MainAxisAlignment.end,
-        children: const <Widget>[
+        children: <Widget>[
           SizedBox(key: child0Key, width: 100.0, height: 100.0),
           SizedBox(key: child1Key, width: 100.0, height: 100.0),
           SizedBox(key: child2Key, width: 100.0, height: 100.0),
@@ -193,11 +193,11 @@ void main() {
 
     // Default is MainAxisSize.max so the Column should be as high as the test: 600.
     // The 100x100 children's top edges should be at 0, 250, 500
-    await tester.pumpWidget(Center(
+    await tester.pumpWidget(const Center(
       child: Column(
         key: columnKey,
         mainAxisAlignment: MainAxisAlignment.spaceBetween,
-        children: const <Widget>[
+        children: <Widget>[
           SizedBox(key: child0Key, width: 100.0, height: 100.0),
           SizedBox(key: child1Key, width: 100.0, height: 100.0),
           SizedBox(key: child2Key, width: 100.0, height: 100.0),
@@ -240,11 +240,11 @@ void main() {
 
     // Default is MainAxisSize.max so the Column should be as high as the test: 600.
     // The 100x100 children's top edges should be at 25, 175, 325, 475
-    await tester.pumpWidget(Center(
+    await tester.pumpWidget(const Center(
       child: Column(
         key: columnKey,
         mainAxisAlignment: MainAxisAlignment.spaceAround,
-        children: const <Widget>[
+        children: <Widget>[
           SizedBox(key: child0Key, width: 100.0, height: 100.0),
           SizedBox(key: child1Key, width: 100.0, height: 100.0),
           SizedBox(key: child2Key, width: 100.0, height: 100.0),
@@ -293,11 +293,11 @@ void main() {
 
     // Default is MainAxisSize.max so the Column should be as high as the test: 600.
     // The 100x20 children's top edges should be at 135, 290, 445
-    await tester.pumpWidget(Center(
+    await tester.pumpWidget(const Center(
       child: Column(
         key: columnKey,
         mainAxisAlignment: MainAxisAlignment.spaceEvenly,
-        children: const <Widget>[
+        children: <Widget>[
           SizedBox(key: child0Key, width: 100.0, height: 20.0),
           SizedBox(key: child1Key, width: 100.0, height: 20.0),
           SizedBox(key: child2Key, width: 100.0, height: 20.0),
@@ -335,10 +335,10 @@ void main() {
     const Key flexKey = Key('flexKey');
 
     // Default is MainAxisSize.max so the Column should be as high as the test: 600.
-    await tester.pumpWidget(Center(
+    await tester.pumpWidget(const Center(
       child: Column(
         key: flexKey,
-        children: const <Widget>[
+        children: <Widget>[
           SizedBox(width: 100.0, height: 100.0),
           SizedBox(width: 100.0, height: 150.0),
         ],
@@ -349,11 +349,11 @@ void main() {
     expect(renderBox.size.height, equals(600.0));
 
     // Column with MainAxisSize.min without flexible children shrink wraps.
-    await tester.pumpWidget(Center(
+    await tester.pumpWidget(const Center(
       child: Column(
         key: flexKey,
         mainAxisSize: MainAxisSize.min,
-        children: const <Widget>[
+        children: <Widget>[
           SizedBox(width: 100.0, height: 100.0),
           SizedBox(width: 100.0, height: 150.0),
         ],
@@ -367,11 +367,11 @@ void main() {
   testWidgets('Column MainAxisSize.min layout at zero size', (WidgetTester tester) async {
     const Key childKey = Key('childKey');
 
-    await tester.pumpWidget(Center(
+    await tester.pumpWidget(const Center(
       child: SizedBox.shrink(
         child: Column(
           mainAxisSize: MainAxisSize.min,
-          children: const <Widget>[
+          children: <Widget>[
             SizedBox(
               key: childKey,
               width: 100.0,
@@ -399,11 +399,11 @@ void main() {
     // Default is MainAxisSize.max so the Column should be as high as the test: 600.
     // Default is MainAxisAlignment.start so children so the children's
     // bottom edges should be at 0, 100, 500 from bottom, child2's height should be 400.
-    await tester.pumpWidget(Center(
+    await tester.pumpWidget(const Center(
       child: Column(
         key: columnKey,
         verticalDirection: VerticalDirection.up,
-        children: const <Widget>[
+        children: <Widget>[
           SizedBox(key: child0Key, width: 100.0, height: 100.0),
           Expanded(child: SizedBox(key: child1Key, width: 100.0, height: 100.0)),
           SizedBox(key: child2Key, width: 100.0, height: 100.0),
@@ -446,11 +446,11 @@ void main() {
     // Default is MainAxisSize.max so the Column should be as high as the test: 600.
     // Default is MainAxisAlignment.start so children so the children's
     // bottom edges should be at 0, 100, 200 from bottom
-    await tester.pumpWidget(Center(
+    await tester.pumpWidget(const Center(
       child: Column(
         key: columnKey,
         verticalDirection: VerticalDirection.up,
-        children: const <Widget>[
+        children: <Widget>[
           SizedBox(key: child0Key, width: 100.0, height: 100.0),
           SizedBox(key: child1Key, width: 100.0, height: 100.0),
           SizedBox(key: child2Key, width: 100.0, height: 100.0),
@@ -491,12 +491,12 @@ void main() {
 
     // Default is MainAxisSize.max so the Column should be as high as the test: 600.
     // The 100x100 children's bottom edges should be at 200, 300 from bottom
-    await tester.pumpWidget(Center(
+    await tester.pumpWidget(const Center(
       child: Column(
         key: columnKey,
         mainAxisAlignment: MainAxisAlignment.center,
         verticalDirection: VerticalDirection.up,
-        children: const <Widget>[
+        children: <Widget>[
           SizedBox(key: child0Key, width: 100.0, height: 100.0),
           SizedBox(key: child1Key, width: 100.0, height: 100.0),
         ],
@@ -531,12 +531,12 @@ void main() {
 
     // Default is MainAxisSize.max so the Column should be as high as the test: 600.
     // The 100x100 children's bottom edges should be at 300, 400, 500 from bottom.
-    await tester.pumpWidget(Center(
+    await tester.pumpWidget(const Center(
       child: Column(
         key: columnKey,
         mainAxisAlignment: MainAxisAlignment.end,
         verticalDirection: VerticalDirection.up,
-        children: const <Widget>[
+        children: <Widget>[
           SizedBox(key: child0Key, width: 100.0, height: 100.0),
           SizedBox(key: child1Key, width: 100.0, height: 100.0),
           SizedBox(key: child2Key, width: 100.0, height: 100.0),
@@ -578,12 +578,12 @@ void main() {
 
     // Default is MainAxisSize.max so the Column should be as high as the test: 600.
     // The 100x100 children's bottom edges should be at 0, 250, 500 from bottom
-    await tester.pumpWidget(Center(
+    await tester.pumpWidget(const Center(
       child: Column(
         key: columnKey,
         mainAxisAlignment: MainAxisAlignment.spaceBetween,
         verticalDirection: VerticalDirection.up,
-        children: const <Widget>[
+        children: <Widget>[
           SizedBox(key: child0Key, width: 100.0, height: 100.0),
           SizedBox(key: child1Key, width: 100.0, height: 100.0),
           SizedBox(key: child2Key, width: 100.0, height: 100.0),
@@ -626,12 +626,12 @@ void main() {
 
     // Default is MainAxisSize.max so the Column should be as high as the test: 600.
     // The 100x100 children's bottom edges should be at 25, 175, 325, 475 from bottom
-    await tester.pumpWidget(Center(
+    await tester.pumpWidget(const Center(
       child: Column(
         key: columnKey,
         mainAxisAlignment: MainAxisAlignment.spaceAround,
         verticalDirection: VerticalDirection.up,
-        children: const <Widget>[
+        children: <Widget>[
           SizedBox(key: child0Key, width: 100.0, height: 100.0),
           SizedBox(key: child1Key, width: 100.0, height: 100.0),
           SizedBox(key: child2Key, width: 100.0, height: 100.0),
@@ -680,12 +680,12 @@ void main() {
 
     // Default is MainAxisSize.max so the Column should be as high as the test: 600.
     // The 100x20 children's bottom edges should be at 135, 290, 445 from bottom
-    await tester.pumpWidget(Center(
+    await tester.pumpWidget(const Center(
       child: Column(
         key: columnKey,
         mainAxisAlignment: MainAxisAlignment.spaceEvenly,
         verticalDirection: VerticalDirection.up,
-        children: const <Widget>[
+        children: <Widget>[
           SizedBox(key: child0Key, width: 100.0, height: 20.0),
           SizedBox(key: child1Key, width: 100.0, height: 20.0),
           SizedBox(key: child2Key, width: 100.0, height: 20.0),
@@ -723,11 +723,11 @@ void main() {
     const Key flexKey = Key('flexKey');
 
     // Default is MainAxisSize.max so the Column should be as high as the test: 600.
-    await tester.pumpWidget(Center(
+    await tester.pumpWidget(const Center(
       child: Column(
         key: flexKey,
         verticalDirection: VerticalDirection.up,
-        children: const <Widget>[
+        children: <Widget>[
           SizedBox(width: 100.0, height: 100.0),
           SizedBox(width: 100.0, height: 150.0),
         ],
@@ -738,12 +738,12 @@ void main() {
     expect(renderBox.size.height, equals(600.0));
 
     // Column with MainAxisSize.min without flexible children shrink wraps.
-    await tester.pumpWidget(Center(
+    await tester.pumpWidget(const Center(
       child: Column(
         key: flexKey,
         mainAxisSize: MainAxisSize.min,
         verticalDirection: VerticalDirection.up,
-        children: const <Widget>[
+        children: <Widget>[
           SizedBox(width: 100.0, height: 100.0),
           SizedBox(width: 100.0, height: 150.0),
         ],
@@ -757,12 +757,12 @@ void main() {
   testWidgets('Column MainAxisSize.min layout at zero size', (WidgetTester tester) async {
     const Key childKey = Key('childKey');
 
-    await tester.pumpWidget(Center(
+    await tester.pumpWidget(const Center(
       child: SizedBox.shrink(
         child: Column(
           mainAxisSize: MainAxisSize.min,
           verticalDirection: VerticalDirection.up,
-          children: const <Widget>[
+          children: <Widget>[
             SizedBox(
               key: childKey,
               width: 100.0,

packages/flutter/test/widgets/dismissible_test.dart

@@ -640,14 +640,14 @@ void main() {
   // Dismissible contract. This is not an example of good practice.
   testWidgets('dismissing bottom then top (smoketest)', (WidgetTester tester) async {
     await tester.pumpWidget(
-      Directionality(
+      const Directionality(
         textDirection: TextDirection.ltr,
         child: Center(
           child: SizedBox(
             width: 100.0,
             height: 1000.0,
             child: Column(
-              children: const <Widget>[
+              children: <Widget>[
                 Test1215DismissibleWidget('1'),
                 Test1215DismissibleWidget('2'),
               ],

packages/flutter/test/widgets/draggable_test.dart

@@ -1752,9 +1752,9 @@ void main() {
     await gesture.moveTo(secondLocation);
     await tester.pump();
 
-    await tester.pumpWidget(MaterialApp(
+    await tester.pumpWidget(const MaterialApp(
         home: Column(
-            children: const <Widget>[
+            children: <Widget>[
               Draggable<int>(
                   data: 1,
                   feedback: Text('Dragging'),
@@ -2284,9 +2284,9 @@ void main() {
     await gesture.moveTo(secondLocation);
     await tester.pump();
 
-    await tester.pumpWidget(MaterialApp(
+    await tester.pumpWidget(const MaterialApp(
       home: Column(
-        children: const <Widget>[
+        children: <Widget>[
           Draggable<int>(
             data: 1,
             feedback: Text('Dragging'),
@@ -3061,9 +3061,9 @@ void main() {
     const HitTestBehavior hitTestBehavior = HitTestBehavior.deferToChild;
 
     await tester.pumpWidget(
-      MaterialApp(
+      const MaterialApp(
         home: Column(
-          children: const <Widget>[
+          children: <Widget>[
             Draggable<int>(
               feedback: SizedBox(height: 50.0, child: Text('Draggable')),
               child: SizedBox(height: 50.0, child: Text('Target')),
@@ -3079,9 +3079,9 @@ void main() {
   // Regression test for https://github.com/flutter/flutter/issues/92083
   testWidgets('feedback respect the MouseRegion cursor configure', (WidgetTester tester) async {
     await tester.pumpWidget(
-      MaterialApp(
+      const MaterialApp(
         home: Column(
-          children: const <Widget>[
+          children: <Widget>[
             Draggable<int>(
               ignoringFeedbackPointer: false,
               feedback: MouseRegion(

packages/flutter/test/widgets/flex_test.dart

@@ -49,9 +49,9 @@ void main() {
 
   testWidgets('Flexible defaults to loose', (WidgetTester tester) async {
     await tester.pumpWidget(
-      Row(
+      const Row(
         textDirection: TextDirection.ltr,
-        children: const <Widget>[
+        children: <Widget>[
           Flexible(child: SizedBox(width: 100.0, height: 200.0)),
         ],
       ),
@@ -64,11 +64,11 @@ void main() {
   testWidgets("Doesn't overflow because of floating point accumulated error", (WidgetTester tester) async {
     // both of these cases have failed in the past due to floating point issues
     await tester.pumpWidget(
-      Center(
+      const Center(
         child: SizedBox(
           height: 400.0,
           child: Column(
-            children: const <Widget>[
+            children: <Widget>[
               Expanded(child: SizedBox()),
               Expanded(child: SizedBox()),
               Expanded(child: SizedBox()),
@@ -81,11 +81,11 @@ void main() {
       ),
     );
     await tester.pumpWidget(
-      Center(
+      const Center(
         child: SizedBox(
           height: 199.0,
           child: Column(
-            children: const <Widget>[
+            children: <Widget>[
               Expanded(child: SizedBox()),
               Expanded(child: SizedBox()),
               Expanded(child: SizedBox()),
@@ -104,7 +104,7 @@ void main() {
     // we only get a single exception. Otherwise we'd get two, the one we want and
     // an extra one when we discover we never computed a size.
     await tester.pumpWidget(
-      Column(
+      const Column(
         children: <Widget>[
           Column(),
         ],
@@ -134,11 +134,17 @@ void main() {
   });
 
   testWidgets('Can set and update clipBehavior', (WidgetTester tester) async {
-    await tester.pumpWidget(Flex(direction: Axis.vertical));
+    await tester.pumpWidget(const Flex(direction: Axis.vertical));
     final RenderFlex renderObject = tester.allRenderObjects.whereType<RenderFlex>().first;
     expect(renderObject.clipBehavior, equals(Clip.none));
 
-    await tester.pumpWidget(Flex(direction: Axis.vertical, clipBehavior: Clip.antiAlias));
+    await tester.pumpWidget(const Flex(direction: Axis.vertical, clipBehavior: Clip.antiAlias));
     expect(renderObject.clipBehavior, equals(Clip.antiAlias));
   });
+
+  test('Flex/Column/Row can be const-constructed', () {
+    const Flex(direction: Axis.vertical);
+    const Column();
+    const Row();
+  });
 }

packages/flutter/test/widgets/implicit_semantics_test.dart

@@ -17,8 +17,8 @@ void main() {
         textDirection: TextDirection.ltr,
         child: Semantics(
           container: true,
-          child: Column(
-            children: const <Widget>[
+          child: const Column(
+            children: <Widget>[
               Text('Michael Goderbauer'),
               Text('goderbauer@google.com'),
             ],
@@ -51,8 +51,8 @@ void main() {
         child: Semantics(
           container: true,
           explicitChildNodes: true,
-          child: Column(
-            children: const <Widget>[
+          child: const Column(
+            children: <Widget>[
               Text('Michael Goderbauer'),
               Text('goderbauer@google.com'),
             ],
@@ -98,8 +98,8 @@ void main() {
           explicitChildNodes: true,
           child: Semantics(
             label: 'Signed in as',
-            child: Column(
-              children: const <Widget>[
+            child: const Column(
+              children: <Widget>[
                 Text('Michael Goderbauer'),
                 Text('goderbauer@google.com'),
               ],
@@ -140,8 +140,8 @@ void main() {
           container: true,
           child: Semantics(
             label: 'Signed in as',
-            child: Column(
-              children: const <Widget>[
+            child: const Column(
+              children: <Widget>[
                 Text('Michael Goderbauer'),
                 Text('goderbauer@google.com'),
               ],

packages/flutter/test/widgets/list_body_test.dart

@@ -29,9 +29,9 @@ void expectRects(WidgetTester tester, List<Rect> expected) {
 void main() {
 
   testWidgets('ListBody down', (WidgetTester tester) async {
-    await tester.pumpWidget(Flex(
+    await tester.pumpWidget(const Flex(
       direction: Axis.vertical,
-      children: const <Widget>[ ListBody(children: children) ],
+      children: <Widget>[ ListBody(children: children) ],
     ));
 
     expectRects(
@@ -46,9 +46,9 @@ void main() {
   });
 
   testWidgets('ListBody up', (WidgetTester tester) async {
-    await tester.pumpWidget(Flex(
+    await tester.pumpWidget(const Flex(
       direction: Axis.vertical,
-      children: const <Widget>[ ListBody(reverse: true, children: children) ],
+      children: <Widget>[ ListBody(reverse: true, children: children) ],
     ));
 
     expectRects(
@@ -63,10 +63,10 @@ void main() {
   });
 
   testWidgets('ListBody right', (WidgetTester tester) async {
-    await tester.pumpWidget(Flex(
+    await tester.pumpWidget(const Flex(
       textDirection: TextDirection.ltr,
       direction: Axis.horizontal,
-      children: const <Widget>[
+      children: <Widget>[
         Directionality(
           textDirection: TextDirection.ltr,
           child: ListBody(mainAxis: Axis.horizontal, children: children),
@@ -86,10 +86,10 @@ void main() {
   });
 
   testWidgets('ListBody left', (WidgetTester tester) async {
-    await tester.pumpWidget(Flex(
+    await tester.pumpWidget(const Flex(
       textDirection: TextDirection.ltr,
       direction: Axis.horizontal,
-      children: const <Widget>[
+      children: <Widget>[
         Directionality(
           textDirection: TextDirection.rtl,
           child: ListBody(mainAxis: Axis.horizontal, children: children),
@@ -147,7 +147,7 @@ void main() {
     FlutterError.onError = (FlutterErrorDetails error) => errors.add(error);
     try {
       await tester.pumpWidget(
-        Flex(
+        const Flex(
           textDirection: TextDirection.ltr,
           direction: Axis.horizontal,
           children: <Widget>[
@@ -159,7 +159,7 @@ void main() {
                   Flex(
                     textDirection: TextDirection.ltr,
                     direction: Axis.vertical,
-                    children: const <Widget>[
+                    children: <Widget>[
                       Directionality(
                         textDirection: TextDirection.ltr,
                         child: ListBody(

packages/flutter/test/widgets/multichildobject_with_keys_test.dart

@@ -11,10 +11,10 @@ void main() {
     // Regression test for https://github.com/flutter/flutter/issues/48855.
 
     await tester.pumpWidget(
-      Directionality(
+      const Directionality(
         textDirection: TextDirection.ltr,
         child: Column(
-          children: const <Widget>[
+          children: <Widget>[
             Text('0', key: ValueKey<int>(0)),
             Text('1', key: ValueKey<int>(1)),
             Text('2', key: ValueKey<int>(2)),
@@ -35,10 +35,10 @@ void main() {
     );
 
     await tester.pumpWidget(
-      Directionality(
+      const Directionality(
         textDirection: TextDirection.ltr,
         child: Column(
-          children: const <Widget>[
+          children: <Widget>[
             Text('0', key: ValueKey<int>(0)),
             Text('6', key: ValueKey<int>(6)),
             Text('7', key: ValueKey<int>(7)),
@@ -62,8 +62,8 @@ void main() {
   testWidgets('Building a new MultiChildRenderObjectElement with children having duplicated keys throws', (WidgetTester tester) async {
     const ValueKey<int> duplicatedKey = ValueKey<int>(1);
 
-    await tester.pumpWidget(Column(
-      children: const <Widget>[
+    await tester.pumpWidget(const Column(
+      children: <Widget>[
         Text('Text 1', textDirection: TextDirection.ltr, key: duplicatedKey),
         Text('Text 2', textDirection: TextDirection.ltr, key: duplicatedKey),
       ],

packages/flutter/test/widgets/parent_data_test.dart

@@ -292,11 +292,11 @@ void main() {
     checkTree(tester, <TestParentData>[]);
 
     await tester.pumpWidget(
-      Directionality(
+      const Directionality(
         textDirection: TextDirection.ltr,
         child: DummyWidget(
           child: Row(
-            children: const <Widget>[
+            children: <Widget>[
               Positioned(
                 top: 6.0,
                 left: 7.0,

packages/flutter/test/widgets/physical_model_test.dart

@@ -47,15 +47,15 @@ void main() {
   testWidgets('PhysicalModel - clips when overflows and elevation is 0', (WidgetTester tester) async {
     const Key key = Key('test');
     await tester.pumpWidget(
-      MediaQuery(
+      const MediaQuery(
         key: key,
-        data: const MediaQueryData(),
+        data: MediaQueryData(),
         child: Directionality(
           textDirection: TextDirection.ltr,
           child: Padding(
-            padding: const EdgeInsets.all(50),
+            padding: EdgeInsets.all(50),
             child: Row(
-              children: const <Widget>[
+              children: <Widget>[
                 Material(child: Text('A long long long long long long long string')),
                 Material(child: Text('A long long long long long long long string')),
                 Material(child: Text('A long long long long long long long string')),

packages/flutter/test/widgets/rich_text_test.dart

@@ -147,17 +147,17 @@ void main() {
             color: Colors.green,
             child: IntrinsicHeight(
               child: RichText(
-                text: TextSpan(
+                text: const TextSpan(
                   children: <InlineSpan>[
-                    const TextSpan(text: 'Start\n', style: TextStyle(height: 1.0, fontSize: 16)),
+                    TextSpan(text: 'Start\n', style: TextStyle(height: 1.0, fontSize: 16)),
                     WidgetSpan(
                       child: Row(
-                        children: const <Widget>[
+                        children: <Widget>[
                           SizedBox(height: 16, width: 16),
                         ],
                       ),
                     ),
-                    const TextSpan(text: 'End', style: TextStyle(height: 1.0, fontSize: 16)),
+                    TextSpan(text: 'End', style: TextStyle(height: 1.0, fontSize: 16)),
                   ],
                 ),
               ),

packages/flutter/test/widgets/row_test.dart

@@ -284,12 +284,12 @@ void main() {
     OrderPainter.log.clear();
     const Key childKey = Key('childKey');
 
-    await tester.pumpWidget(Center(
+    await tester.pumpWidget(const Center(
       child: SizedBox.shrink(
         child: Row(
           mainAxisSize: MainAxisSize.min,
           mainAxisAlignment: MainAxisAlignment.center,
-          children: const <Widget>[
+          children: <Widget>[
             SizedBox(
               key: childKey,
               width: 100.0,
@@ -704,13 +704,13 @@ void main() {
     OrderPainter.log.clear();
     const Key childKey = Key('childKey');
 
-    await tester.pumpWidget(Center(
+    await tester.pumpWidget(const Center(
       child: SizedBox.shrink(
         child: Row(
           textDirection: TextDirection.ltr,
           mainAxisSize: MainAxisSize.min,
           mainAxisAlignment: MainAxisAlignment.center,
-          children: const <Widget>[
+          children: <Widget>[
             SizedBox(
               key: childKey,
               width: 100.0,
@@ -1125,13 +1125,13 @@ void main() {
     OrderPainter.log.clear();
     const Key childKey = Key('childKey');
 
-    await tester.pumpWidget(Center(
+    await tester.pumpWidget(const Center(
       child: SizedBox.shrink(
         child: Row(
           textDirection: TextDirection.rtl,
           mainAxisSize: MainAxisSize.min,
           mainAxisAlignment: MainAxisAlignment.center,
-          children: const <Widget>[
+          children: <Widget>[
             SizedBox(
               key: childKey,
               width: 100.0,

packages/flutter/test/widgets/safe_area_test.dart

@@ -113,10 +113,10 @@ void main() {
       }
 
       testWidgets('SafeArea alone.', (WidgetTester tester) async {
-        final Widget child = boilerplate(SafeArea(
+        final Widget child = boilerplate(const SafeArea(
           maintainBottomViewPadding: true,
           child: Column(
-            children: const <Widget>[
+            children: <Widget>[
               Expanded(child: Placeholder()),
             ],
           ),
@@ -148,10 +148,10 @@ void main() {
       });
 
       testWidgets('SafeArea alone - partial ViewInsets consume Padding', (WidgetTester tester) async {
-        final Widget child = boilerplate(SafeArea(
+        final Widget child = boilerplate(const SafeArea(
           maintainBottomViewPadding: true,
           child: Column(
-            children: const <Widget>[
+            children: <Widget>[
               Expanded(child: Placeholder()),
             ],
           ),
@@ -181,12 +181,12 @@ void main() {
       });
 
       testWidgets('SafeArea with nested Scaffold', (WidgetTester tester) async {
-        final Widget child = boilerplate(SafeArea(
+        final Widget child = boilerplate(const SafeArea(
           maintainBottomViewPadding: true,
           child: Scaffold(
             resizeToAvoidBottomInset: false,
             body: Column(
-              children: const <Widget>[
+              children: <Widget>[
                 Expanded(child: Placeholder()),
               ],
             ),
@@ -219,12 +219,12 @@ void main() {
       });
 
       testWidgets('SafeArea with nested Scaffold  - partial ViewInsets consume Padding', (WidgetTester tester) async {
-        final Widget child = boilerplate(SafeArea(
+        final Widget child = boilerplate(const SafeArea(
           maintainBottomViewPadding: true,
           child: Scaffold(
             resizeToAvoidBottomInset: false,
             body: Column(
-              children: const <Widget>[
+              children: <Widget>[
                 Expanded(child: Placeholder()),
               ],
             ),

packages/flutter/test/widgets/selectable_region_test.dart

@@ -409,8 +409,8 @@ void main() {
           home: SelectableRegion(
             focusNode: FocusNode(),
             selectionControls: materialTextSelectionControls,
-            child: Column(
-              children: const <Widget>[
+            child: const Column(
+              children: <Widget>[
                 Text('How are you?'),
                 Text('Good, and you?'),
                 Text('Fine, thank you.'),
@@ -449,8 +449,8 @@ void main() {
           home: SelectableRegion(
             focusNode: FocusNode(),
             selectionControls: materialTextSelectionControls,
-            child: Column(
-              children: const <Widget>[
+            child: const Column(
+              children: <Widget>[
                 Text('How are you?'),
                 SelectionContainer.disabled(child: Text('Good, and you?')),
                 Text('Fine, thank you.'),
@@ -490,8 +490,8 @@ void main() {
           home: SelectableRegion(
             focusNode: FocusNode(),
             selectionControls: materialTextSelectionControls,
-            child: Column(
-              children: const <Widget>[
+            child: const Column(
+              children: <Widget>[
                 Text('How are you?'),
                 Text('Good, and you?'),
                 Text('Fine, thank you.'),
@@ -529,8 +529,8 @@ void main() {
           home: SelectableRegion(
             focusNode: FocusNode(),
             selectionControls: materialTextSelectionControls,
-            child: Column(
-              children: const <Widget>[
+            child: const Column(
+              children: <Widget>[
                 Text('How are you?'),
                 Text('Good, and you?'),
                 Text('Fine, thank you.'),
@@ -665,8 +665,8 @@ void main() {
           home: SelectableRegion(
             focusNode: focusNode,
             selectionControls: materialTextSelectionControls,
-            child: Column(
-              children: const <Widget>[
+            child: const Column(
+              children: <Widget>[
                 Text('How are you?'),
                 Text('Good, and you?'),
                 Text('Fine, thank you.'),
@@ -813,8 +813,8 @@ void main() {
           home: SelectableRegion(
             focusNode: FocusNode(),
             selectionControls: materialTextSelectionControls,
-            child: Column(
-              children: const <Widget>[
+            child: const Column(
+              children: <Widget>[
                 Text('How are you?'),
                 Text('جيد وانت؟', textDirection: TextDirection.rtl),
                 Text('Fine, thank you.'),
@@ -854,8 +854,8 @@ void main() {
           home: SelectableRegion(
             focusNode: FocusNode(),
             selectionControls: materialTextSelectionControls,
-            child: Column(
-              children: const <Widget>[
+            child: const Column(
+              children: <Widget>[
                 Text('How are you?'),
                 Text('Good, and you?'),
                 Text('Fine, thank you.'),
@@ -954,8 +954,8 @@ void main() {
           home: SelectableRegion(
             focusNode: FocusNode(),
             selectionControls: materialTextSelectionControls,
-            child: Column(
-              children: const <Widget>[
+            child: const Column(
+              children: <Widget>[
                 Text('How are you?'),
                 Text('Good, and you?'),
                 Text('Fine, thank you.'),
@@ -995,8 +995,8 @@ void main() {
           home: SelectableRegion(
             focusNode: FocusNode(),
             selectionControls: materialTextSelectionControls,
-            child: Column(
-              children: const <Widget>[
+            child: const Column(
+              children: <Widget>[
                 Text('How are you?'),
                 Text('Good, and you?'),
                 Text('Fine, thank you.'),
@@ -1031,8 +1031,8 @@ void main() {
           home: SelectableRegion(
             focusNode: FocusNode(),
             selectionControls: materialTextSelectionControls,
-            child: Column(
-              children: const <Widget>[
+            child: const Column(
+              children: <Widget>[
                 Text('How are you?'),
                 Text('Good, and you?'),
                 Text('Fine, thank you.'),
@@ -1067,8 +1067,8 @@ void main() {
           home: SelectableRegion(
             focusNode: FocusNode(),
             selectionControls: materialTextSelectionControls,
-            child: Column(
-              children: const <Widget>[
+            child: const Column(
+              children: <Widget>[
                 Text('How are you?'),
                 Text('Good, and you?'),
                 Text('Fine, thank you.'),
@@ -1102,8 +1102,8 @@ void main() {
           home: SelectableRegion(
             focusNode: FocusNode(),
             selectionControls: materialTextSelectionControls,
-            child: Column(
-              children: const <Widget>[
+            child: const Column(
+              children: <Widget>[
                 Text('How are you?'),
                 Text('Good, and you?'),
                 Text('Fine, thank you.'),
@@ -1141,8 +1141,8 @@ void main() {
           home: SelectableRegion(
             focusNode: FocusNode(),
             selectionControls: materialTextSelectionControls,
-            child: Column(
-              children: const <Widget>[
+            child: const Column(
+              children: <Widget>[
                 Text('How are you?'),
                 Text('Good, and you?'),
                 Text('Fine, thank you.'),
@@ -1201,8 +1201,8 @@ void main() {
           home: SelectableRegion(
             focusNode: FocusNode(),
             selectionControls: materialTextSelectionControls,
-            child: Column(
-              children: const <Widget>[
+            child: const Column(
+              children: <Widget>[
                 Text('How are you?'),
                 Text('Good, and you?'),
                 Text('Fine, thank you.'),
@@ -1311,8 +1311,8 @@ void main() {
           home: SelectableRegion(
             focusNode: FocusNode(),
             selectionControls: materialTextSelectionControls,
-            child: Column(
-              children: const <Widget>[
+            child: const Column(
+              children: <Widget>[
                 Text('How are you?'),
                 Text('Good, and you?'),
                 Text('Fine, thank you.'),
@@ -1402,8 +1402,8 @@ void main() {
           home: SelectableRegion(
             focusNode: FocusNode(),
             selectionControls: materialTextSelectionControls,
-            child: Column(
-              children: const <Widget>[
+            child: const Column(
+              children: <Widget>[
                 Text('How are you?'),
                 Text('Good, and you?'),
                 Text('Fine, thank you.'),
@@ -1480,8 +1480,8 @@ void main() {
           home: SelectableRegion(
             focusNode: FocusNode(),
             selectionControls: materialTextSelectionControls,
-            child: Column(
-              children: const <Widget>[
+            child: const Column(
+              children: <Widget>[
                 Text('How are you?'),
                 Text('Good, and you?'),
                 Text('Fine, thank you.'),

packages/flutter/test/widgets/selectable_text_test.dart

@@ -5079,11 +5079,11 @@ void main() {
 
   testWidgets('text selection style 1', (WidgetTester tester) async {
     await tester.pumpWidget(
-      MaterialApp(
+      const MaterialApp(
         home: Material(
           child: Center(
             child: Column(
-              children: const <Widget>[
+              children: <Widget>[
                 SelectableText.rich(
                   TextSpan(
                     children: <TextSpan>[
@@ -5131,11 +5131,11 @@ void main() {
 
   testWidgets('text selection style 2', (WidgetTester tester) async {
     await tester.pumpWidget(
-      MaterialApp(
+      const MaterialApp(
         home: Material(
           child: Center(
             child: Column(
-              children: const <Widget>[
+              children: <Widget>[
                 SelectableText.rich(
                   TextSpan(
                     children: <TextSpan>[

packages/flutter/test/widgets/selection_container_test.dart

@@ -25,8 +25,8 @@ void main() {
       SelectionContainer(
         registrar: registrar,
         delegate: delegate,
-        child: Column(
-          children: const <Widget>[
+        child: const Column(
+          children: <Widget>[
             Text('column1', textDirection: TextDirection.ltr),
             Text('column2', textDirection: TextDirection.ltr),
             Text('column3', textDirection: TextDirection.ltr),
@@ -46,9 +46,9 @@ void main() {
       SelectionContainer(
         registrar: registrar,
         delegate: delegate,
-        child: SelectionContainer.disabled(
+        child: const SelectionContainer.disabled(
           child: Column(
-            children: const <Widget>[
+            children: <Widget>[
               Text('column1', textDirection: TextDirection.ltr),
               Text('column2', textDirection: TextDirection.ltr),
               Text('column3', textDirection: TextDirection.ltr),
@@ -69,7 +69,7 @@ void main() {
       SelectionContainer(
         registrar: registrar,
         delegate: delegate,
-        child: Column(
+        child: const Column(
         ),
       ),
     );
@@ -80,8 +80,8 @@ void main() {
       SelectionContainer(
         registrar: registrar,
         delegate: delegate,
-        child: Column(
-          children: const <Widget>[
+        child: const Column(
+          children: <Widget>[
             Text('column1', textDirection: TextDirection.ltr),
           ],
         ),
@@ -94,7 +94,7 @@ void main() {
       SelectionContainer(
         registrar: registrar,
         delegate: delegate,
-        child: Column(
+        child: const Column(
         ),
       ),
     );
@@ -111,8 +111,8 @@ void main() {
         registrar: registrar,
         child: SelectionContainer(
           delegate: delegate,
-          child: Column(
-            children: const <Widget>[
+          child: const Column(
+            children: <Widget>[
               Text('column1', textDirection: TextDirection.ltr),
             ],
           ),

packages/flutter/test/widgets/semantics_clipping_test.dart

@@ -12,7 +12,7 @@ void main() {
   testWidgets('SemanticNode.rect is clipped', (WidgetTester tester) async {
     final SemanticsTester semantics = SemanticsTester(tester);
 
-    await tester.pumpWidget(Directionality(
+    await tester.pumpWidget(const Directionality(
       textDirection: TextDirection.ltr,
       child: Center(
         child: SizedBox(
@@ -20,7 +20,7 @@ void main() {
           child: Flex(
             clipBehavior: Clip.hardEdge,
             direction: Axis.horizontal,
-            children: const <Widget>[
+            children: <Widget>[
               SizedBox(
                 width: 75.0,
                 child: Text('1'),
@@ -70,7 +70,7 @@ void main() {
   testWidgets('SemanticsNode is not removed if out of bounds and merged into something within bounds', (WidgetTester tester) async {
     final SemanticsTester semantics = SemanticsTester(tester);
 
-    await tester.pumpWidget(Directionality(
+    await tester.pumpWidget(const Directionality(
       textDirection: TextDirection.ltr,
       child: Center(
         child: SizedBox(
@@ -79,14 +79,14 @@ void main() {
             clipBehavior: Clip.hardEdge,
             direction: Axis.horizontal,
             children: <Widget>[
-              const SizedBox(
+              SizedBox(
                 width: 75.0,
                 child: Text('1'),
               ),
               MergeSemantics(
                 child: Flex(
                   direction: Axis.horizontal,
-                  children: const <Widget>[
+                  children: <Widget>[
                     SizedBox(
                       width: 75.0,
                       child: Text('2'),

packages/flutter/test/widgets/semantics_test.dart

@@ -1001,14 +1001,14 @@ void main() {
       },
     );
     await tester.pumpWidget(
-      Directionality(
+      const Directionality(
         textDirection: TextDirection.ltr,
         child: Column(
           children: <Widget>[
-            const Text('Label 1'),
-            const Text('Label 2'),
+            Text('Label 1'),
+            Text('Label 2'),
             Row(
-              children: const <Widget>[
+              children: <Widget>[
                 Text('Label 3'),
                 Text('Label 4'),
                 Text('Label 5'),
@@ -1070,8 +1070,8 @@ void main() {
             const Text('Label 2'),
             Transform.rotate(
               angle: pi / 2.0,
-              child: Row(
-                children: const <Widget>[
+              child: const Row(
+                children: <Widget>[
                   Text('Label 3'),
                   Text('Label 4'),
                   Text('Label 5'),
@@ -1638,7 +1638,7 @@ void main() {
     // Construct a widget tree that will end up with a fitted box that applies
     // a zero transform because it does not actually draw its children.
     // Assert that this subtree gets dropped (the root node has no children).
-    await tester.pumpWidget(Column(
+    await tester.pumpWidget(const Column(
       children: <Widget>[
         SizedBox(
           height: 0,

packages/flutter/test/widgets/spacer_test.dart

@@ -7,8 +7,8 @@ import 'package:flutter_test/flutter_test.dart';
 
 void main() {
   testWidgets('Spacer takes up space.', (WidgetTester tester) async {
-    await tester.pumpWidget(Column(
-      children: const <Widget>[
+    await tester.pumpWidget(const Column(
+      children: <Widget>[
         SizedBox(width: 10.0, height: 10.0),
         Spacer(),
         SizedBox(width: 10.0, height: 10.0),
@@ -24,9 +24,9 @@ void main() {
     const Spacer spacer2 = Spacer();
     const Spacer spacer3 = Spacer(flex: 2);
     const Spacer spacer4 = Spacer(flex: 4);
-    await tester.pumpWidget(Row(
+    await tester.pumpWidget(const Row(
       textDirection: TextDirection.rtl,
-      children: const <Widget>[
+      children: <Widget>[
         SizedBox(width: 10.0, height: 10.0),
         spacer1,
         SizedBox(width: 10.0, height: 10.0),
@@ -54,10 +54,10 @@ void main() {
   });
 
   testWidgets('Spacer takes up space.', (WidgetTester tester) async {
-    await tester.pumpWidget(UnconstrainedBox(
+    await tester.pumpWidget(const UnconstrainedBox(
       constrainedAxis: Axis.vertical,
       child: Column(
-        children: const <Widget>[
+        children: <Widget>[
           SizedBox(width: 20.0, height: 10.0),
           Spacer(),
           SizedBox(width: 10.0, height: 10.0),

packages/flutter/test/widgets/syncing_test.dart

@@ -130,7 +130,7 @@ void main() {
   testWidgets('swap instances around', (WidgetTester tester) async {
     const Widget a = TestWidget(persistentState: 0x61, syncedState: 0x41, child: Text('apple', textDirection: TextDirection.ltr));
     const Widget b = TestWidget(persistentState: 0x62, syncedState: 0x42, child: Text('banana', textDirection: TextDirection.ltr));
-    await tester.pumpWidget(Column());
+    await tester.pumpWidget(const Column());
 
     final GlobalKey keyA = GlobalKey();
     final GlobalKey keyB = GlobalKey();

packages/flutter/test/widgets/text_golden_test.dart

@@ -1331,8 +1331,8 @@ void main() {
             decoration: const BoxDecoration(
               color: Color(0xff00ff00),
             ),
-            child: Column(
-              children: const <Widget>[
+            child: const Column(
+              children: <Widget>[
                 Text('Hello\nLine 2\nLine 3',
                   textDirection: TextDirection.ltr,
                   style: TextStyle(height: 5),

packages/flutter/test/widgets/text_test.dart

@@ -1012,13 +1012,13 @@ void main() {
 
   testWidgets('textWidthBasis with textAlign still obeys parent alignment', (WidgetTester tester) async {
     await tester.pumpWidget(
-      MaterialApp(
+      const MaterialApp(
         home: Scaffold(
           body: Center(
             child: Column(
               mainAxisSize: MainAxisSize.min,
               crossAxisAlignment: CrossAxisAlignment.start,
-              children: const <Widget>[
+              children: <Widget>[
                 Text(
                   'LEFT ALIGNED, PARENT',
                   textAlign: TextAlign.left,

packages/flutter/test/widgets/ticker_mode_test.dart

@@ -190,8 +190,8 @@ void main() {
       routes: <String, WidgetBuilder>{
         '/foo' : (BuildContext context) => const Text('New route'),
       },
-      home: Row(
-        children: const <Widget>[
+      home: const Row(
+        children: <Widget>[
           _TickingWidget(),
           _MultiTickingWidget(),
           Text('Old route'),

packages/flutter/test/widgets/transform_test.dart

@@ -808,7 +808,7 @@ void main() {
             ),
             const ColoredBox(color: Color(0xff00ff00), child: square),
           ]),
-          Row(mainAxisSize: MainAxisSize.min, children: const <Widget>[
+          const Row(mainAxisSize: MainAxisSize.min, children: <Widget>[
             ColoredBox(color: Color(0xff0000ff), child: square),
             ColoredBox(color: Color(0xffeeff00), child: square),
           ]),

packages/flutter/test/widgets/widget_inspector_test.dart

@@ -4303,11 +4303,11 @@ class _TestWidgetInspectorService extends TestWidgetInspectorService {
       });
 
       Future<void> pumpWidgetForLayoutExplorer(WidgetTester tester) async {
-        final Widget widget = Directionality(
+        const Widget widget = Directionality(
           textDirection: TextDirection.ltr,
           child: Center(
             child: Row(
-              children: const <Widget>[
+              children: <Widget>[
                 Flexible(
                   child: ColoredBox(
                     color: Colors.green,
@@ -4959,9 +4959,9 @@ class _TestWidgetInspectorService extends TestWidgetInspectorService {
             appBar: AppBar(
               title: const Text('Hello World!'),
             ),
-            body: Center(
+            body: const Center(
               child: Column(
-                children: const <Widget>[
+                children: <Widget>[
                   Text('Hello World!'),
                 ],
               ),

packages/flutter/test/widgets/wrap_test.dart

@@ -841,8 +841,8 @@ void main() {
 
   testWidgets('Object exactly matches container width', (WidgetTester tester) async {
     await tester.pumpWidget(
-      Column(
-        children: const <Widget>[
+      const Column(
+        children: <Widget>[
           Wrap(
             textDirection: TextDirection.ltr,
             spacing: 10.0,
@@ -859,8 +859,8 @@ void main() {
     verify(tester, <Offset>[Offset.zero]);
 
     await tester.pumpWidget(
-      Column(
-        children: const <Widget>[
+      const Column(
+        children: <Widget>[
           Wrap(
             textDirection: TextDirection.ltr,
             spacing: 10.0,
@@ -893,7 +893,7 @@ void main() {
   testWidgets('Horizontal wrap - IntrinsicsHeight', (WidgetTester tester) async {
     // Regression test for https://github.com/flutter/flutter/issues/48679.
     await tester.pumpWidget(
-      Directionality(
+      const Directionality(
         textDirection: TextDirection.ltr,
         child: Center(
           child: IntrinsicHeight(
@@ -901,13 +901,13 @@ void main() {
               color: Colors.green,
               child: Wrap(
                 children: <Widget>[
-                  const Text('Start', style: TextStyle(height: 1.0, fontSize: 16)),
+                  Text('Start', style: TextStyle(height: 1.0, fontSize: 16)),
                   Row(
-                    children: const <Widget>[
+                    children: <Widget>[
                       SizedBox(height: 40, width: 60),
                     ],
                   ),
-                  const Text('End', style: TextStyle(height: 1.0, fontSize: 16)),
+                  Text('End', style: TextStyle(height: 1.0, fontSize: 16)),
                 ],
               ),
             ),
@@ -925,7 +925,7 @@ void main() {
   testWidgets('Vertical wrap - IntrinsicsWidth', (WidgetTester tester) async {
     // Regression test for https://github.com/flutter/flutter/issues/48679.
     await tester.pumpWidget(
-      Directionality(
+      const Directionality(
         textDirection: TextDirection.ltr,
         child: Center(
           child: IntrinsicWidth(
@@ -934,13 +934,13 @@ void main() {
               child: Wrap(
                 direction: Axis.vertical,
                 children: <Widget>[
-                  const Text('Start', style: TextStyle(height: 1.0, fontSize: 16)),
+                  Text('Start', style: TextStyle(height: 1.0, fontSize: 16)),
                   Column(
-                    children: const <Widget>[
+                    children: <Widget>[
                       SizedBox(height: 40, width: 60),
                     ],
                   ),
-                  const Text('End', style: TextStyle(height: 1.0, fontSize: 16)),
+                  Text('End', style: TextStyle(height: 1.0, fontSize: 16)),
                 ],
               ),
             ),