Make MultiChildRenderObjectWidget const (#119195)

dev/benchmarks/platform_views_layout/lib/main.dart

@@ -55,8 +55,8 @@ class PlatformViewLayout extends StatelessWidget {
             child: Material(
               elevation: (index % 5 + 1).toDouble(),
               color: Colors.white,
-              child: Stack(
-                children: const <Widget> [
+              child: const Stack(
+                children: <Widget> [
                   DummyPlatformView(),
                   RotationContainer(),
                 ],

dev/benchmarks/platform_views_layout_hybrid_composition/lib/main.dart

@@ -59,8 +59,8 @@ class PlatformViewLayout extends StatelessWidget {
             child: Material(
               elevation: (index % 5 + 1).toDouble(),
               color: Colors.white,
-              child: Stack(
-                children: const <Widget> [
+              child: const Stack(
+                children: <Widget> [
                   DummyPlatformView(),
                   RotationContainer(),
                 ],

dev/integration_tests/android_semantics_testing/lib/src/tests/popup_page.dart

@@ -77,9 +77,9 @@ class _PopupControlsPageState extends State<PopupControlsPage> {
                       return AlertDialog(
                         key: const ValueKey<String>(alertKeyValue),
                         title: const Text('Title text', key: ValueKey<String>('$alertKeyValue.Title')),
-                        content: SingleChildScrollView(
+                        content: const SingleChildScrollView(
                           child: ListBody(
-                            children: const <Widget>[
+                            children: <Widget>[
                               Text('Body text line 1.', key: ValueKey<String>('$alertKeyValue.Body1')),
                               Text('Body text line 2.', key: ValueKey<String>('$alertKeyValue.Body2')),
                             ],

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

@@ -1763,7 +1763,7 @@ class CupertinoDialogAction extends StatelessWidget {
 //
 // See [_RenderCupertinoDialogActions] for specific layout policy details.
 class _CupertinoDialogActionsRenderWidget extends MultiChildRenderObjectWidget {
-  _CupertinoDialogActionsRenderWidget({
+  const _CupertinoDialogActionsRenderWidget({
     required List<Widget> actionButtons,
     double dividerThickness = 0.0,
     bool hasCancelButton = false,

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

@@ -405,7 +405,7 @@ class _SegmentedControlState<T extends Object> extends State<CupertinoSegmentedC
 }
 
 class _SegmentedControlRenderWidget<T> extends MultiChildRenderObjectWidget {
-  _SegmentedControlRenderWidget({
+  const _SegmentedControlRenderWidget({
     super.key,
     super.children,
     required this.selectedIndex,

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

@@ -711,7 +711,7 @@ class _SegmentedControlState<T> extends State<CupertinoSlidingSegmentedControl<T
 }
 
 class _SegmentedControlRenderWidget<T> extends MultiChildRenderObjectWidget {
-  _SegmentedControlRenderWidget({
+  const _SegmentedControlRenderWidget({
     super.key,
     super.children,
     required this.highlightedIndex,

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/dialog.dart

@@ -302,9 +302,9 @@ class Dialog extends StatelessWidget {
 ///     builder: (BuildContext context) {
 ///       return AlertDialog(
 ///         title: const Text('AlertDialog Title'),
-///         content: SingleChildScrollView(
+///         content: const SingleChildScrollView(
 ///           child: ListBody(
-///             children: const <Widget>[
+///             children: <Widget>[
 ///               Text('This is a demo alert dialog.'),
 ///               Text('Would you like to approve of this message?'),
 ///             ],

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

@@ -605,7 +605,7 @@ class _ArrowDownIntent extends Intent {
 }
 
 class _DropdownMenuBody extends MultiChildRenderObjectWidget {
-  _DropdownMenuBody({
+  const _DropdownMenuBody({
     super.key,
     super.children,
     this.width,

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

@@ -655,7 +655,7 @@ class _MergeableMaterialSliceKey extends GlobalKey {
 }
 
 class _MergeableMaterialListBody extends ListBody {
-  _MergeableMaterialListBody({
+  const _MergeableMaterialListBody({
     required super.children,
     super.mainAxis,
     required this.items,

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

@@ -372,7 +372,7 @@ class SegmentedButton<T> extends StatelessWidget {
   }
 }
 class _SegmentedButtonRenderWidget<T> extends MultiChildRenderObjectWidget {
-  _SegmentedButtonRenderWidget({
+  const _SegmentedButtonRenderWidget({
     super.key,
     required this.segments,
     required this.enabledBorder,

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/material/text_selection_toolbar.dart

@@ -373,7 +373,7 @@ class _TextSelectionToolbarTrailingEdgeAlignRenderBox extends RenderProxyBox {
 // Renders the menu items in the correct positions in the menu and its overflow
 // submenu based on calculating which item would first overflow.
 class _TextSelectionToolbarItemsLayout extends MultiChildRenderObjectWidget {
-  _TextSelectionToolbarItemsLayout({
+  const _TextSelectionToolbarItemsLayout({
     required this.isAbove,
     required this.overflowOpen,
     required super.children,

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

@@ -2304,7 +2304,7 @@ class CustomMultiChildLayout extends MultiChildRenderObjectWidget {
   /// Creates a custom multi-child layout.
   ///
   /// The [delegate] argument must not be null.
-  CustomMultiChildLayout({
+  const CustomMultiChildLayout({
     super.key,
     required this.delegate,
     super.children,
@@ -3666,7 +3666,7 @@ class ListBody extends MultiChildRenderObjectWidget {
   /// given axis.
   ///
   /// By default, the [mainAxis] is [Axis.vertical].
-  ListBody({
+  const ListBody({
     super.key,
     this.mainAxis = Axis.vertical,
     this.reverse = false,
@@ -3825,7 +3825,7 @@ class Stack extends MultiChildRenderObjectWidget {
   ///
   /// By default, the non-positioned children of the stack are aligned by their
   /// top left corners.
-  Stack({
+  const Stack({
     super.key,
     this.alignment = AlignmentDirectional.topStart,
     this.textDirection,
@@ -3941,7 +3941,7 @@ class IndexedStack extends Stack {
   /// Creates a [Stack] widget that paints a single child.
   ///
   /// The [index] argument must not be null.
-  IndexedStack({
+  const IndexedStack({
     super.key,
     super.alignment,
     super.textDirection,
@@ -4445,7 +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.
-  Flex({
+  const Flex({
     super.key,
     required this.direction,
     this.mainAxisAlignment = MainAxisAlignment.start,
@@ -4812,7 +4812,7 @@ 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,
@@ -5005,7 +5005,7 @@ 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,
@@ -5212,7 +5212,7 @@ class Wrap 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.
-  Wrap({
+  const Wrap({
     super.key,
     this.direction = Axis.horizontal,
     this.alignment = WrapAlignment.start,
@@ -5474,7 +5474,7 @@ class Flow extends MultiChildRenderObjectWidget {
   /// a repaint boundary.
   ///
   /// The [delegate] argument must not be null.
-  Flow.unwrapped({
+  const Flow.unwrapped({
     super.key,
     required this.delegate,
     super.children,

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

@@ -1855,9 +1855,7 @@ abstract class MultiChildRenderObjectWidget extends RenderObjectWidget {
   ///
   /// The [children] argument must not be null and must not contain any null
   /// objects.
-  // TODO(goderbauer): Make this const and fix fallout, https://github.com/flutter/flutter/issues/108248
-  // ignore: prefer_const_constructors_in_immutables
-  MultiChildRenderObjectWidget({ super.key, this.children = const <Widget>[] });
+  const MultiChildRenderObjectWidget({ super.key, this.children = const <Widget>[] });
 
   /// The widgets below this widget in the tree.
   ///

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

@@ -59,7 +59,7 @@ class OverflowBar extends MultiChildRenderObjectWidget {
   /// [overflowDirection], and [clipBehavior] parameters must not be
   /// null. The [children] argument must not be null and must not contain
   /// any null objects.
-  OverflowBar({
+  const OverflowBar({
     super.key,
     this.spacing = 0.0,
     this.alignment,

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

@@ -637,7 +637,7 @@ class OverlayState extends State<Overlay> with TickerProviderStateMixin {
 ///
 /// The first [skipCount] children are considered "offstage".
 class _Theatre extends MultiChildRenderObjectWidget {
-  _Theatre({
+  const _Theatre({
     this.skipCount = 0,
     this.clipBehavior = Clip.hardEdge,
     super.children,

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

@@ -324,7 +324,7 @@ class ShrinkWrappingViewport extends MultiChildRenderObjectWidget {
   /// rebuild this widget when the [offset] changes.
   ///
   /// The [offset] argument must not be null.
-  ShrinkWrappingViewport({
+  const ShrinkWrappingViewport({
     super.key,
     this.axisDirection = AxisDirection.down,
     this.crossAxisDirection,

packages/flutter/test/cupertino/scaffold_test.dart

@@ -227,7 +227,7 @@ void main() {
                   ),
                   child: page1Center,
                 )
-                : Stack();
+                : const Stack();
           },
         ),
       ),
@@ -270,7 +270,7 @@ void main() {
                       ],
                     ),
                   )
-                  : Stack();
+                  : const Stack();
             },
           ),
         ),

packages/flutter/test/material/button_bar_test.dart

@@ -341,9 +341,9 @@ void main() {
 
     testWidgets('ButtonBar has a min height of 52 when using ButtonBarLayoutBehavior.constrained', (WidgetTester tester) async {
       await tester.pumpWidget(
-        SingleChildScrollView(
+        const SingleChildScrollView(
           child: ListBody(
-            children: const <Widget>[
+            children: <Widget>[
               Directionality(
                 textDirection: TextDirection.ltr,
                 child: ButtonBar(
@@ -364,9 +364,9 @@ void main() {
 
     testWidgets('ButtonBar has padding applied when using ButtonBarLayoutBehavior.padded', (WidgetTester tester) async {
       await tester.pumpWidget(
-        SingleChildScrollView(
+        const SingleChildScrollView(
           child: ListBody(
-            children: const <Widget>[
+            children: <Widget>[
               Directionality(
                 textDirection: TextDirection.ltr,
                 child: ButtonBar(

packages/flutter/test/material/icons_test.dart

@@ -63,11 +63,11 @@ void main() {
   testWidgets('A sample of icons look as expected', (WidgetTester tester) async {
     await _loadIconFont();
 
-    await tester.pumpWidget(MaterialApp(
+    await tester.pumpWidget(const MaterialApp(
       home: IconTheme(
-        data: const IconThemeData(size: 200),
+        data: IconThemeData(size: 200),
         child: Wrap(
-          children: const <Icon>[
+          children: <Icon>[
             Icon(Icons.ten_k),
             Icon(Icons.ac_unit),
             Icon(Icons.local_taxi),
@@ -87,11 +87,11 @@ void main() {
   testWidgets('Another sample of icons look as expected', (WidgetTester tester) async {
     await _loadIconFont();
 
-    await tester.pumpWidget(MaterialApp(
+    await tester.pumpWidget(const MaterialApp(
       home: IconTheme(
-        data: const IconThemeData(size: 200),
+        data: IconThemeData(size: 200),
         child: Wrap(
-          children: const <Icon>[
+          children: <Icon>[
             Icon(Icons.water_drop),
             Icon(Icons.water_drop_outlined),
             Icon(Icons.water_drop_rounded),
@@ -107,11 +107,11 @@ void main() {
   testWidgets('Another sample of icons look as expected', (WidgetTester tester) async {
     await _loadIconFont();
 
-    await tester.pumpWidget(MaterialApp(
+    await tester.pumpWidget(const MaterialApp(
       home: IconTheme(
-        data: const IconThemeData(size: 200),
+        data: IconThemeData(size: 200),
         child: Wrap(
-          children: const <Icon>[
+          children: <Icon>[
             Icon(Icons.electric_bolt),
             Icon(Icons.electric_bolt_outlined),
             Icon(Icons.electric_bolt_rounded),
@@ -128,11 +128,11 @@ void main() {
   testWidgets('Another sample of icons look as expected', (WidgetTester tester) async {
     await _loadIconFont();
 
-    await tester.pumpWidget(MaterialApp(
+    await tester.pumpWidget(const MaterialApp(
       home: IconTheme(
-        data: const IconThemeData(size: 200),
+        data: IconThemeData(size: 200),
         child: Wrap(
-          children: const <Icon>[
+          children: <Icon>[
             Icon(Icons.repeat_on),
             Icon(Icons.repeat_on_outlined),
             Icon(Icons.repeat_on_rounded),

packages/flutter/test/material/input_decorator_test.dart

@@ -5903,14 +5903,14 @@ void main() {
     };
     try {
       await tester.pumpWidget(
-        MaterialApp(
+        const MaterialApp(
           home: Center(
             child: Directionality(
               textDirection: TextDirection.ltr,
               child: InputDecorator(
-                decoration: const InputDecoration(),
+                decoration: InputDecoration(),
                 child: Stack(
-                  children: const <Widget>[
+                  children: <Widget>[
                     SizedBox(height: 0),
                     Positioned(
                       bottom: 5,

packages/flutter/test/material/navigation_rail_test.dart

@@ -2652,10 +2652,10 @@ void main() {
       navigationRail: NavigationRail(
         labelType: NavigationRailLabelType.none,
         selectedIndex: 0,
-        destinations:  <NavigationRailDestination>[
+        destinations:  const <NavigationRailDestination>[
           NavigationRailDestination(
             icon: Stack(
-              children: const <Widget>[
+              children: <Widget>[
                 Icon(Icons.umbrella),
                 Positioned(
                   top: 0,
@@ -2667,13 +2667,13 @@ void main() {
                 ),
               ],
             ),
-            label: const Text('Abc'),
+            label: Text('Abc'),
           ),
-          const NavigationRailDestination(
+          NavigationRailDestination(
             icon: Icon(Icons.umbrella),
             label: Text('Def'),
           ),
-          const NavigationRailDestination(
+          NavigationRailDestination(
             icon: Icon(Icons.bookmark_border),
             label: Text('Ghi'),
           ),
@@ -4867,10 +4867,10 @@ void main() {
         navigationRail: NavigationRail(
           labelType: NavigationRailLabelType.none,
           selectedIndex: 0,
-          destinations:  <NavigationRailDestination>[
+          destinations:  const <NavigationRailDestination>[
             NavigationRailDestination(
               icon: Stack(
-                children: const <Widget>[
+                children: <Widget>[
                   Icon(Icons.umbrella),
                   Positioned(
                     top: 0,
@@ -4882,13 +4882,13 @@ void main() {
                   ),
                 ],
               ),
-              label: const Text('Abc'),
+              label: Text('Abc'),
             ),
-            const NavigationRailDestination(
+            NavigationRailDestination(
               icon: Icon(Icons.umbrella),
               label: Text('Def'),
             ),
-            const NavigationRailDestination(
+            NavigationRailDestination(
               icon: Icon(Icons.bookmark_border),
               label: Text('Ghi'),
             ),

packages/flutter/test/widgets/automatic_keep_alive_test.dart

@@ -230,23 +230,23 @@ void main() {
           addRepaintBoundaries: false,
           addSemanticIndexes: false,
           cacheExtent: 0.0,
-          children: <Widget>[
+          children: const <Widget>[
             AutomaticKeepAlive(
               child: SizedBox(
                 height: 400.0,
-                child: Stack(children: const <Widget>[
+                child: Stack(children: <Widget>[
                   Leaf(key: GlobalObjectKey<_LeafState>(0), child: Placeholder()),
                   Leaf(key: GlobalObjectKey<_LeafState>(1), child: Placeholder()),
                 ]),
               ),
             ),
-            const AutomaticKeepAlive(
+            AutomaticKeepAlive(
               child: SizedBox(
                 key: GlobalObjectKey<_LeafState>(2),
                 height: 400.0,
               ),
             ),
-            const AutomaticKeepAlive(
+            AutomaticKeepAlive(
               child: SizedBox(
                 key: GlobalObjectKey<_LeafState>(3),
                 height: 400.0,
@@ -314,11 +314,11 @@ void main() {
           addRepaintBoundaries: false,
           addSemanticIndexes: false,
           cacheExtent: 0.0,
-          children: <Widget>[
+          children: const <Widget>[
             AutomaticKeepAlive(
               child: SizedBox(
                 height: 400.0,
-                child: Stack(children: const <Widget>[
+                child: Stack(children: <Widget>[
                   Leaf(key: GlobalObjectKey<_LeafState>(0), child: Placeholder()),
                   Leaf(key: GlobalObjectKey<_LeafState>(1), child: Placeholder()),
                 ]),
@@ -327,7 +327,7 @@ void main() {
             AutomaticKeepAlive(
               child: SizedBox(
                 height: 400.0,
-                child: Stack(children: const <Widget>[
+                child: Stack(children: <Widget>[
                   Leaf(key: GlobalObjectKey<_LeafState>(2), child: Placeholder()),
                   Leaf(key: GlobalObjectKey<_LeafState>(3), child: Placeholder()),
                 ]),
@@ -336,7 +336,7 @@ void main() {
             AutomaticKeepAlive(
               child: SizedBox(
                 height: 400.0,
-                child: Stack(children: const <Widget>[
+                child: Stack(children: <Widget>[
                   Leaf(key: GlobalObjectKey<_LeafState>(4), child: Placeholder()),
                   Leaf(key: GlobalObjectKey<_LeafState>(5), child: Placeholder()),
                 ]),
@@ -370,11 +370,11 @@ void main() {
         addRepaintBoundaries: false,
         addSemanticIndexes: false,
         cacheExtent: 0.0,
-        children: <Widget>[
+        children: const <Widget>[
           AutomaticKeepAlive(
             child: SizedBox(
               height: 400.0,
-              child: Stack(children: const <Widget>[
+              child: Stack(children: <Widget>[
                 Leaf(key: GlobalObjectKey<_LeafState>(1), child: Placeholder()),
               ]),
             ),
@@ -382,7 +382,7 @@ void main() {
           AutomaticKeepAlive(
             child: SizedBox(
               height: 400.0,
-              child: Stack(children: const <Widget>[
+              child: Stack(children: <Widget>[
                 Leaf(key: GlobalObjectKey<_LeafState>(2), child: Placeholder()),
                 Leaf(key: GlobalObjectKey<_LeafState>(3), child: Placeholder()),
               ]),
@@ -391,7 +391,7 @@ void main() {
           AutomaticKeepAlive(
             child: SizedBox(
               height: 400.0,
-              child: Stack(children: const <Widget>[
+              child: Stack(children: <Widget>[
                 Leaf(key: GlobalObjectKey<_LeafState>(4), child: Placeholder()),
                 Leaf(key: GlobalObjectKey<_LeafState>(5), child: Placeholder()),
                 Leaf(key: GlobalObjectKey<_LeafState>(0), child: Placeholder()),
@@ -434,11 +434,11 @@ void main() {
         addRepaintBoundaries: false,
         addSemanticIndexes: false,
         cacheExtent: 0.0,
-        children: <Widget>[
+        children: const <Widget>[
           AutomaticKeepAlive(
             child: SizedBox(
               height: 400.0,
-              child: Stack(children: const <Widget>[
+              child: Stack(children: <Widget>[
                 Leaf(key: GlobalObjectKey<_LeafState>(1), child: Placeholder()),
                 Leaf(key: GlobalObjectKey<_LeafState>(2), child: Placeholder()),
               ]),
@@ -453,7 +453,7 @@ void main() {
           AutomaticKeepAlive(
             child: SizedBox(
               height: 400.0,
-              child: Stack(children: const <Widget>[
+              child: Stack(children: <Widget>[
                 Leaf(key: GlobalObjectKey<_LeafState>(3), child: Placeholder()),
                 Leaf(key: GlobalObjectKey<_LeafState>(4), child: Placeholder()),
                 Leaf(key: GlobalObjectKey<_LeafState>(5), child: Placeholder()),

packages/flutter/test/widgets/basic_test.dart

@@ -911,12 +911,12 @@ void main() {
 
   testWidgets('Wrap implements debugFillProperties', (WidgetTester tester) async {
     final DiagnosticPropertiesBuilder builder = DiagnosticPropertiesBuilder();
-    Wrap(
+    const Wrap(
       spacing: 8.0, // gap between adjacent Text widget
       runSpacing: 4.0, // gap between lines
       textDirection: TextDirection.ltr,
       verticalDirection: VerticalDirection.up,
-      children: const <Widget>[
+      children: <Widget>[
         Text('Hamilton'),
         Text('Lafayette'),
         Text('Mulligan'),

packages/flutter/test/widgets/global_keys_duplicated_test.dart

@@ -12,7 +12,7 @@ void main() {
   testWidgets('GlobalKey children of one node', (WidgetTester tester) async {
     // This is actually a test of the regular duplicate key logic, which
     // happens before the duplicate GlobalKey logic.
-    await tester.pumpWidget(Stack(children: const <Widget>[
+    await tester.pumpWidget(const Stack(children: <Widget>[
       DummyWidget(key: GlobalObjectKey(0)),
       DummyWidget(key: GlobalObjectKey(0)),
     ]));
@@ -24,9 +24,9 @@ void main() {
   });
 
   testWidgets('GlobalKey children of two nodes - A', (WidgetTester tester) async {
-    await tester.pumpWidget(Stack(
+    await tester.pumpWidget(const Stack(
       textDirection: TextDirection.ltr,
-      children: const <Widget>[
+      children: <Widget>[
         DummyWidget(child: DummyWidget(key: GlobalObjectKey(0))),
         DummyWidget(
           child: DummyWidget(key: GlobalObjectKey(0),
@@ -44,9 +44,9 @@ void main() {
   });
 
   testWidgets('GlobalKey children of two different nodes - B', (WidgetTester tester) async {
-    await tester.pumpWidget(Stack(
+    await tester.pumpWidget(const Stack(
       textDirection: TextDirection.ltr,
-      children: const <Widget>[
+      children: <Widget>[
         DummyWidget(child: DummyWidget(key: GlobalObjectKey(0))),
         DummyWidget(key: Key('x'), child: DummyWidget(key:  GlobalObjectKey(0))),
       ],

packages/flutter/test/widgets/list_body_test.dart

@@ -31,7 +31,7 @@ void main() {
   testWidgets('ListBody down', (WidgetTester tester) async {
     await tester.pumpWidget(Flex(
       direction: Axis.vertical,
-      children: <Widget>[ ListBody(children: children) ],
+      children: const <Widget>[ ListBody(children: children) ],
     ));
 
     expectRects(
@@ -48,7 +48,7 @@ void main() {
   testWidgets('ListBody up', (WidgetTester tester) async {
     await tester.pumpWidget(Flex(
       direction: Axis.vertical,
-      children: <Widget>[ ListBody(reverse: true, children: children) ],
+      children: const <Widget>[ ListBody(reverse: true, children: children) ],
     ));
 
     expectRects(
@@ -66,7 +66,7 @@ void main() {
     await tester.pumpWidget(Flex(
       textDirection: TextDirection.ltr,
       direction: Axis.horizontal,
-      children: <Widget>[
+      children: const <Widget>[
         Directionality(
           textDirection: TextDirection.ltr,
           child: ListBody(mainAxis: Axis.horizontal, children: children),
@@ -89,7 +89,7 @@ void main() {
     await tester.pumpWidget(Flex(
       textDirection: TextDirection.ltr,
       direction: Axis.horizontal,
-      children: <Widget>[
+      children: const <Widget>[
         Directionality(
           textDirection: TextDirection.rtl,
           child: ListBody(mainAxis: Axis.horizontal, children: children),
@@ -114,7 +114,7 @@ void main() {
     FlutterError.onError = (FlutterErrorDetails error) => errors.add(error);
     try {
       await tester.pumpWidget(
-        SizedBox(
+        const SizedBox(
           width: 100,
           height: 100,
           child: Directionality(
@@ -159,7 +159,7 @@ void main() {
                   Flex(
                     textDirection: TextDirection.ltr,
                     direction: Axis.vertical,
-                    children: <Widget>[
+                    children: const <Widget>[
                       Directionality(
                         textDirection: TextDirection.ltr,
                         child: ListBody(

packages/flutter/test/widgets/modal_barrier_test.dart

@@ -910,9 +910,9 @@ void main() {
   });
 
   testWidgets('uses default mouse cursor', (WidgetTester tester) async {
-    await tester.pumpWidget(Stack(
+    await tester.pumpWidget(const Stack(
       textDirection: TextDirection.ltr,
-      children: const <Widget>[
+      children: <Widget>[
         MouseRegion(cursor: SystemMouseCursors.click),
         ModalBarrier(dismissible: false),
       ],

packages/flutter/test/widgets/multichild_test.dart

@@ -35,9 +35,9 @@ void main() {
   testWidgets('MultiChildRenderObjectElement control test', (WidgetTester tester) async {
 
     await tester.pumpWidget(
-      Stack(
+      const Stack(
         textDirection: TextDirection.ltr,
-        children: const <Widget>[
+        children: <Widget>[
           DecoratedBox(decoration: kBoxDecorationA),
           DecoratedBox(decoration: kBoxDecorationB),
           DecoratedBox(decoration: kBoxDecorationC),
@@ -48,9 +48,9 @@ void main() {
     checkTree(tester, <BoxDecoration>[kBoxDecorationA, kBoxDecorationB, kBoxDecorationC]);
 
     await tester.pumpWidget(
-      Stack(
+      const Stack(
         textDirection: TextDirection.ltr,
-        children: const <Widget>[
+        children: <Widget>[
           DecoratedBox(decoration: kBoxDecorationA),
           DecoratedBox(decoration: kBoxDecorationC),
         ],
@@ -60,9 +60,9 @@ void main() {
     checkTree(tester, <BoxDecoration>[kBoxDecorationA, kBoxDecorationC]);
 
     await tester.pumpWidget(
-      Stack(
+      const Stack(
         textDirection: TextDirection.ltr,
-        children: const <Widget>[
+        children: <Widget>[
           DecoratedBox(decoration: kBoxDecorationA),
           DecoratedBox(key: Key('b'), decoration: kBoxDecorationB),
           DecoratedBox(decoration: kBoxDecorationC),
@@ -73,9 +73,9 @@ void main() {
     checkTree(tester, <BoxDecoration>[kBoxDecorationA, kBoxDecorationB, kBoxDecorationC]);
 
     await tester.pumpWidget(
-      Stack(
+      const Stack(
         textDirection: TextDirection.ltr,
-        children: const <Widget>[
+        children: <Widget>[
           DecoratedBox(key: Key('b'), decoration: kBoxDecorationB),
           DecoratedBox(decoration: kBoxDecorationC),
           DecoratedBox(key: Key('a'), decoration: kBoxDecorationA),
@@ -86,9 +86,9 @@ void main() {
     checkTree(tester, <BoxDecoration>[kBoxDecorationB, kBoxDecorationC, kBoxDecorationA]);
 
     await tester.pumpWidget(
-      Stack(
+      const Stack(
         textDirection: TextDirection.ltr,
-        children: const <Widget>[
+        children: <Widget>[
           DecoratedBox(key: Key('a'), decoration: kBoxDecorationA),
           DecoratedBox(decoration: kBoxDecorationC),
           DecoratedBox(key: Key('b'), decoration: kBoxDecorationB),
@@ -99,9 +99,9 @@ void main() {
     checkTree(tester, <BoxDecoration>[kBoxDecorationA, kBoxDecorationC, kBoxDecorationB]);
 
     await tester.pumpWidget(
-      Stack(
+      const Stack(
         textDirection: TextDirection.ltr,
-        children: const <Widget>[
+        children: <Widget>[
           DecoratedBox(decoration: kBoxDecorationC),
         ],
       ),
@@ -110,7 +110,7 @@ void main() {
     checkTree(tester, <BoxDecoration>[kBoxDecorationC]);
 
     await tester.pumpWidget(
-      Stack(textDirection: TextDirection.ltr),
+      const Stack(textDirection: TextDirection.ltr),
     );
 
     checkTree(tester, <BoxDecoration>[]);
@@ -120,9 +120,9 @@ void main() {
   testWidgets('MultiChildRenderObjectElement with stateless widgets', (WidgetTester tester) async {
 
     await tester.pumpWidget(
-      Stack(
+      const Stack(
         textDirection: TextDirection.ltr,
-        children: const <Widget>[
+        children: <Widget>[
           DecoratedBox(decoration: kBoxDecorationA),
           DecoratedBox(decoration: kBoxDecorationB),
           DecoratedBox(decoration: kBoxDecorationC),
@@ -133,9 +133,9 @@ void main() {
     checkTree(tester, <BoxDecoration>[kBoxDecorationA, kBoxDecorationB, kBoxDecorationC]);
 
     await tester.pumpWidget(
-      Stack(
+      const Stack(
         textDirection: TextDirection.ltr,
-        children: const <Widget>[
+        children: <Widget>[
           DecoratedBox(decoration: kBoxDecorationA),
           DummyWidget(
             child: DecoratedBox(decoration: kBoxDecorationB),
@@ -148,9 +148,9 @@ void main() {
     checkTree(tester, <BoxDecoration>[kBoxDecorationA, kBoxDecorationB, kBoxDecorationC]);
 
     await tester.pumpWidget(
-      Stack(
+      const Stack(
         textDirection: TextDirection.ltr,
-        children: const <Widget>[
+        children: <Widget>[
           DecoratedBox(decoration: kBoxDecorationA),
           DummyWidget(
             child: DummyWidget(
@@ -165,9 +165,9 @@ void main() {
     checkTree(tester, <BoxDecoration>[kBoxDecorationA, kBoxDecorationB, kBoxDecorationC]);
 
     await tester.pumpWidget(
-      Stack(
+      const Stack(
         textDirection: TextDirection.ltr,
-        children: const <Widget>[
+        children: <Widget>[
           DummyWidget(
             child: DummyWidget(
               child: DecoratedBox(decoration: kBoxDecorationB),
@@ -184,9 +184,9 @@ void main() {
     checkTree(tester, <BoxDecoration>[kBoxDecorationB, kBoxDecorationA, kBoxDecorationC]);
 
     await tester.pumpWidget(
-      Stack(
+      const Stack(
         textDirection: TextDirection.ltr,
-        children: const <Widget>[
+        children: <Widget>[
           DummyWidget(
             child: DecoratedBox(decoration: kBoxDecorationB),
           ),
@@ -201,9 +201,9 @@ void main() {
     checkTree(tester, <BoxDecoration>[kBoxDecorationB, kBoxDecorationA, kBoxDecorationC]);
 
     await tester.pumpWidget(
-      Stack(
+      const Stack(
         textDirection: TextDirection.ltr,
-        children: const <Widget>[
+        children: <Widget>[
           DummyWidget(
             key: Key('b'),
             child: DecoratedBox(decoration: kBoxDecorationB),
@@ -219,9 +219,9 @@ void main() {
     checkTree(tester, <BoxDecoration>[kBoxDecorationB, kBoxDecorationA]);
 
     await tester.pumpWidget(
-      Stack(
+      const Stack(
         textDirection: TextDirection.ltr,
-        children: const <Widget>[
+        children: <Widget>[
           DummyWidget(
             key: Key('a'),
             child: DecoratedBox(decoration: kBoxDecorationA),
@@ -237,7 +237,7 @@ void main() {
     checkTree(tester, <BoxDecoration>[kBoxDecorationA, kBoxDecorationB]);
 
     await tester.pumpWidget(
-      Stack(textDirection: TextDirection.ltr),
+      const Stack(textDirection: TextDirection.ltr),
     );
 
     checkTree(tester, <BoxDecoration>[]);
@@ -245,9 +245,9 @@ void main() {
 
   testWidgets('MultiChildRenderObjectElement with stateful widgets', (WidgetTester tester) async {
     await tester.pumpWidget(
-      Stack(
+      const Stack(
         textDirection: TextDirection.ltr,
-        children: const <Widget>[
+        children: <Widget>[
           DecoratedBox(decoration: kBoxDecorationA),
           DecoratedBox(decoration: kBoxDecorationB),
         ],
@@ -257,9 +257,9 @@ void main() {
     checkTree(tester, <BoxDecoration>[kBoxDecorationA, kBoxDecorationB]);
 
     await tester.pumpWidget(
-      Stack(
+      const Stack(
         textDirection: TextDirection.ltr,
-        children: const <Widget>[
+        children: <Widget>[
           FlipWidget(
             left: DecoratedBox(decoration: kBoxDecorationA),
             right: DecoratedBox(decoration: kBoxDecorationB),
@@ -277,9 +277,9 @@ void main() {
     checkTree(tester, <BoxDecoration>[kBoxDecorationB, kBoxDecorationC]);
 
     await tester.pumpWidget(
-      Stack(
+      const Stack(
         textDirection: TextDirection.ltr,
-        children: const <Widget>[
+        children: <Widget>[
           FlipWidget(
             left: DecoratedBox(decoration: kBoxDecorationA),
             right: DecoratedBox(decoration: kBoxDecorationB),
@@ -296,9 +296,9 @@ void main() {
     checkTree(tester, <BoxDecoration>[kBoxDecorationA]);
 
     await tester.pumpWidget(
-      Stack(
+      const Stack(
         textDirection: TextDirection.ltr,
-        children: const <Widget>[
+        children: <Widget>[
           FlipWidget(
             key: Key('flip'),
             left: DecoratedBox(decoration: kBoxDecorationA),
@@ -309,9 +309,9 @@ void main() {
     );
 
     await tester.pumpWidget(
-      Stack(
+      const Stack(
         textDirection: TextDirection.ltr,
-        children: const <Widget>[
+        children: <Widget>[
           DecoratedBox(key: Key('c'), decoration: kBoxDecorationC),
           FlipWidget(
             key: Key('flip'),
@@ -330,9 +330,9 @@ void main() {
     checkTree(tester, <BoxDecoration>[kBoxDecorationC, kBoxDecorationB]);
 
     await tester.pumpWidget(
-      Stack(
+      const Stack(
         textDirection: TextDirection.ltr,
-        children: const <Widget>[
+        children: <Widget>[
           FlipWidget(
             key: Key('flip'),
             left: DecoratedBox(decoration: kBoxDecorationA),

packages/flutter/test/widgets/overflow_bar_test.dart

@@ -7,7 +7,7 @@ import 'package:flutter_test/flutter_test.dart';
 
 void main() {
   testWidgets('OverflowBar documented defaults', (WidgetTester tester) async {
-    final OverflowBar bar = OverflowBar();
+    const OverflowBar bar = OverflowBar();
     expect(bar.spacing, 0);
     expect(bar.alignment, null);
     expect(bar.overflowSpacing, 0);
@@ -26,7 +26,7 @@ void main() {
         child: Center(
           child: ConstrainedBox(
             constraints: BoxConstraints.tight(size),
-            child: OverflowBar(),
+            child: const OverflowBar(),
           ),
         ),
       ),
@@ -35,7 +35,7 @@ void main() {
     expect(tester.getSize(find.byType(OverflowBar)), size);
 
     await tester.pumpWidget(
-      Directionality(
+      const Directionality(
         textDirection: TextDirection.ltr,
         child: Center(
           child: OverflowBar(),
@@ -182,11 +182,11 @@ void main() {
           child: Container(
             width: width,
             alignment: Alignment.topLeft,
-            child: IntrinsicWidth(
+            child: const IntrinsicWidth(
               child: OverflowBar(
                 spacing: 4,
                 overflowSpacing: 8,
-                children: const <Widget>[
+                children: <Widget>[
                   SizedBox(width: 48, height: 50),
                   SizedBox(width: 64, height: 25),
                   SizedBox(width: 32, height: 75),
@@ -213,11 +213,11 @@ void main() {
           child: Container(
             width: maxWidth,
             alignment: Alignment.topLeft,
-            child: IntrinsicHeight(
+            child: const IntrinsicHeight(
               child: OverflowBar(
                 spacing: 4,
                 overflowSpacing: 8,
-                children: const <Widget>[
+                children: <Widget>[
                   SizedBox(width: 48, height: 50),
                   SizedBox(width: 64, height: 25),
                   SizedBox(width: 32, height: 75),

packages/flutter/test/widgets/parent_data_test.dart

@@ -51,9 +51,9 @@ final TestParentData kNonPositioned = TestParentData();
 void main() {
   testWidgets('ParentDataWidget control test', (WidgetTester tester) async {
     await tester.pumpWidget(
-      Stack(
+      const Stack(
         textDirection: TextDirection.ltr,
-        children: const <Widget>[
+        children: <Widget>[
           DecoratedBox(decoration: kBoxDecorationA),
           Positioned(
             top: 10.0,
@@ -72,9 +72,9 @@ void main() {
     ]);
 
     await tester.pumpWidget(
-      Stack(
+      const Stack(
         textDirection: TextDirection.ltr,
-        children: const <Widget>[
+        children: <Widget>[
           Positioned(
             bottom: 5.0,
             right: 7.0,
@@ -101,9 +101,9 @@ void main() {
     const DecoratedBox kDecoratedBoxC = DecoratedBox(decoration: kBoxDecorationC);
 
     await tester.pumpWidget(
-      Stack(
+      const Stack(
         textDirection: TextDirection.ltr,
-        children: const <Widget>[
+        children: <Widget>[
           Positioned(
             bottom: 5.0,
             right: 7.0,
@@ -126,9 +126,9 @@ void main() {
     ]);
 
     await tester.pumpWidget(
-      Stack(
+      const Stack(
         textDirection: TextDirection.ltr,
-        children: const <Widget>[
+        children: <Widget>[
           Positioned(
             bottom: 6.0,
             right: 8.0,
@@ -197,9 +197,9 @@ void main() {
     ]);
 
     await tester.pumpWidget(
-      Stack(
+      const Stack(
         textDirection: TextDirection.ltr,
-        children: const <Widget>[
+        children: <Widget>[
           Positioned(
             right: 10.0,
             child: FlipWidget(left: kDecoratedBoxA, right: kDecoratedBoxB),
@@ -220,9 +220,9 @@ void main() {
     ]);
 
     await tester.pumpWidget(
-      Stack(
+      const Stack(
         textDirection: TextDirection.ltr,
-        children: const <Widget>[
+        children: <Widget>[
           Positioned(
             top: 7.0,
             child: FlipWidget(left: kDecoratedBoxA, right: kDecoratedBoxB),
@@ -243,7 +243,7 @@ void main() {
     ]);
 
     await tester.pumpWidget(
-      Stack(textDirection: TextDirection.ltr),
+      const Stack(textDirection: TextDirection.ltr),
     );
 
     checkTree(tester, <TestParentData>[]);
@@ -251,11 +251,11 @@ void main() {
 
   testWidgets('ParentDataWidget conflicting data', (WidgetTester tester) async {
     await tester.pumpWidget(
-      Directionality(
+      const Directionality(
         textDirection: TextDirection.ltr,
         child: Stack(
           textDirection: TextDirection.ltr,
-          children: const <Widget>[
+          children: <Widget>[
             Positioned(
               top: 5.0,
               bottom: 8.0,
@@ -287,7 +287,7 @@ void main() {
       ),
     );
 
-    await tester.pumpWidget(Stack(textDirection: TextDirection.ltr));
+    await tester.pumpWidget(const Stack(textDirection: TextDirection.ltr));
 
     checkTree(tester, <TestParentData>[]);
 
@@ -325,7 +325,7 @@ void main() {
     );
 
     await tester.pumpWidget(
-      Stack(textDirection: TextDirection.ltr),
+      const Stack(textDirection: TextDirection.ltr),
     );
 
     checkTree(tester, <TestParentData>[]);

packages/flutter/test/widgets/placeholder_test.dart

@@ -13,11 +13,11 @@ void main() {
     expect(tester.renderObject<RenderBox>(find.byType(Placeholder)).size, const Size(800.0, 600.0));
     await tester.pumpWidget(const Center(child: Placeholder()));
     expect(tester.renderObject<RenderBox>(find.byType(Placeholder)).size, const Size(800.0, 600.0));
-    await tester.pumpWidget(Stack(textDirection: TextDirection.ltr, children: const <Widget>[Positioned(top: 0.0, bottom: 0.0, child: Placeholder())]));
+    await tester.pumpWidget(const Stack(textDirection: TextDirection.ltr, children: <Widget>[Positioned(top: 0.0, bottom: 0.0, child: Placeholder())]));
     expect(tester.renderObject<RenderBox>(find.byType(Placeholder)).size, const Size(400.0, 600.0));
-    await tester.pumpWidget(Stack(textDirection: TextDirection.ltr, children: const <Widget>[Positioned(left: 0.0, right: 0.0, child: Placeholder())]));
+    await tester.pumpWidget(const Stack(textDirection: TextDirection.ltr, children: <Widget>[Positioned(left: 0.0, right: 0.0, child: Placeholder())]));
     expect(tester.renderObject<RenderBox>(find.byType(Placeholder)).size, const Size(800.0, 400.0));
-    await tester.pumpWidget(Stack(textDirection: TextDirection.ltr, children: const <Widget>[Positioned(top: 0.0, child: Placeholder(fallbackWidth: 200.0, fallbackHeight: 300.0))]));
+    await tester.pumpWidget(const Stack(textDirection: TextDirection.ltr, children: <Widget>[Positioned(top: 0.0, child: Placeholder(fallbackWidth: 200.0, fallbackHeight: 300.0))]));
     expect(tester.renderObject<RenderBox>(find.byType(Placeholder)).size, const Size(200.0, 300.0));
   });
 

packages/flutter/test/widgets/tap_region_test.dart

@@ -210,7 +210,7 @@ void main() {
                       onTapInside: (PointerEvent event) {
                         tappedInside.add(noGroupKey.value);
                       },
-                      child: Stack(key: noGroupKey),
+                      child: const Stack(key: noGroupKey),
                     ),
                   ),
                   ConstrainedBox(
@@ -221,7 +221,7 @@ void main() {
                       onTapInside: (PointerEvent event) {
                         tappedInside.add(group1AKey.value);
                       },
-                      child: Stack(key: group1AKey),
+                      child: const Stack(key: group1AKey),
                     ),
                   ),
                   ConstrainedBox(
@@ -232,7 +232,7 @@ void main() {
                       onTapInside: (PointerEvent event) {
                         tappedInside.add(group1BKey.value);
                       },
-                      child: Stack(key: group1BKey),
+                      child: const Stack(key: group1BKey),
                     ),
                   ),
                 ],

packages/flutter/test/widgets/text_test.dart

@@ -1332,21 +1332,21 @@ void main() {
             height: 100,
             child: IntrinsicWidth(
               child: RichText(
-                text: TextSpan(
-                  style: const TextStyle(fontSize: 16, height: 1),
+                text: const TextSpan(
+                  style: TextStyle(fontSize: 16, height: 1),
                   children: <InlineSpan>[
-                    const TextSpan(text: 'S '),
+                    TextSpan(text: 'S '),
                     WidgetSpan(
                       alignment: PlaceholderAlignment.top,
                       child: Wrap(
                         direction: Axis.vertical,
-                        children: const <Widget>[
+                        children: <Widget>[
                           SizedBox(width: 200, height: 100),
                           SizedBox(width: 200, height: 30),
                         ],
                       ),
                     ),
-                    const TextSpan(text: ' E'),
+                    TextSpan(text: ' E'),
                   ],
                 ),
               ),