Enable no_default_cases lint (#91530)

analysis_options.yaml

@@ -127,7 +127,7 @@ linter:
     # - literal_only_boolean_expressions # too many false positives: https://github.com/dart-lang/linter/issues/453
     - missing_whitespace_between_adjacent_strings
     - no_adjacent_strings_in_list
-    # - no_default_cases # too many false positives
+    - no_default_cases
     - no_duplicate_case_values
     - no_logic_in_create_state
     # - no_runtimeType_toString # ok in tests; we enable this only in packages/

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

@@ -64,7 +64,7 @@ class _FilteredChildAnimationPageState extends State<FilteredChildAnimationPage>
       case FilterType.opacity: return 'Fading Child Animation';
       case FilterType.rotateTransform: return 'Transformed Child Animation';
       case FilterType.rotateFilter: return 'Matrix Filtered Child Animation';
-      default: return 'Static Child';
+      case null: return 'Static Child';
     }
   }
 

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

@@ -70,8 +70,10 @@ void _setTestMode(_TestMode? mode) {
     case _TestMode.useCanvasTextLayout:
       useCanvasText = true;
       break;
-    default:
+    case _TestMode.useCanvasKit:
+    case null:
       // Keep as null.
+      break;
   }
   js_util.callMethod(
     html.window,

dev/devicelab/lib/framework/devices.dart

@@ -74,8 +74,6 @@ abstract class DeviceDiscovery {
       case DeviceOperatingSystem.fake:
         print('Looking for fake devices! You should not see this in release builds.');
         return FakeDeviceDiscovery();
-      default:
-        throw DeviceException('Unsupported device operating system: $deviceOperatingSystem');
     }
   }
 

dev/integration_tests/channels/lib/src/test_step.dart

@@ -47,7 +47,7 @@ class TestStepResult {
           return snapshot.data!;
         }
         return snapshot.error! as TestStepResult;
-      default:
+      case ConnectionState.active:
         throw 'Unsupported state ${snapshot.connectionState}';
     }
   }

dev/integration_tests/flutter_gallery/lib/demo/calculator/logic.dart

@@ -257,8 +257,6 @@ class CalcExpression {
       case ExpressionState.NumberWithPoint:
       case ExpressionState.Result:
         return appendOperation(Operation.Subtraction);
-      default:
-        return null;
     }
   }
 

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

@@ -608,7 +608,7 @@ class Tab2ConversationBubble extends StatelessWidget {
         backgroundColor = CupertinoTheme.of(context).primaryColor;
         foregroundColor = CupertinoColors.white;
         break;
-      default:
+      case null:
         break;
     }
 

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

@@ -219,7 +219,7 @@ class _ListDemoState extends State<ListDemo> {
       case _MaterialListType.threeLine:
         itemTypeText = 'Three-line';
         break;
-      default:
+      case null:
         break;
     }
 

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

@@ -156,7 +156,7 @@ class _ListDemoState extends State<ReorderableListDemo> {
           ),
         );
         break;
-      default:
+      case null:
         listTile = Container(
           key: Key(item.value),
         );

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

@@ -169,8 +169,6 @@ class ScrollableTabsDemoState extends State<ScrollableTabsDemo> with SingleTicke
                 return Tab(icon: Icon(page.icon));
               case TabsDemoStyle.textOnly:
                 return Tab(text: page.text);
-              default:
-                return Tab();
             }
           }).toList()
         ),

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

@@ -90,7 +90,7 @@ class _CustomRangeThumbShape extends RangeSliderThumbShape {
           case Thumb.end:
             thumbPath = _leftTriangle(size, center);
             break;
-          default:
+          case null:
             break;
         }
         break;
@@ -102,11 +102,11 @@ class _CustomRangeThumbShape extends RangeSliderThumbShape {
           case Thumb.end:
             thumbPath = _rightTriangle(size, center);
             break;
-          default:
+          case null:
             break;
         }
         break;
-      default:
+      case null:
         break;
     }
     canvas.drawPath(thumbPath, Paint()..color = colorTween.evaluate(enableAnimation)!);

dev/integration_tests/flutter_gallery/lib/demo/shrine/supplemental/cut_corners_border.dart

@@ -116,7 +116,7 @@ class CutCornersBorder extends OutlineInputBorder {
           canvas.drawPath(path, paint);
           break;
         }
-        default:
+        case null:
           break;
       }
     }

dev/integration_tests/flutter_gallery/lib/gallery/options.dart

@@ -408,8 +408,8 @@ class _PlatformItem extends StatelessWidget {
   final GalleryOptions? options;
   final ValueChanged<GalleryOptions>? onOptionsChanged;
 
-  String? _platformLabel(TargetPlatform? platform) {
-    switch(platform) {
+  String _platformLabel(TargetPlatform platform) {
+    switch (platform) {
       case TargetPlatform.android:
         return 'Mountain View';
       case TargetPlatform.fuchsia:
@@ -422,9 +422,6 @@ class _PlatformItem extends StatelessWidget {
         return 'Material Desktop (macOS)';
       case TargetPlatform.windows:
         return 'Material Desktop (Windows)';
-      default:
-        assert(false);
-        return null;
     }
   }
 
@@ -439,7 +436,7 @@ class _PlatformItem extends StatelessWidget {
               children: <Widget>[
                 const Text('Platform mechanics'),
                  Text(
-                   _platformLabel(options!.platform)!,
+                   _platformLabel(options!.platform!),
                    style: Theme.of(context).primaryTextTheme.bodyText2,
                  ),
               ],
@@ -452,7 +449,7 @@ class _PlatformItem extends StatelessWidget {
               return TargetPlatform.values.map((TargetPlatform platform) {
                 return PopupMenuItem<TargetPlatform>(
                   value: platform,
-                  child: Text(_platformLabel(platform)!),
+                  child: Text(_platformLabel(platform)),
                 );
               }).toList();
             },

dev/integration_tests/platform_interaction/lib/src/test_step.dart

@@ -28,7 +28,7 @@ class TestStepResult {
           final Object? result = snapshot.error;
           return result! as TestStepResult;
         }
-      default:
+      case ConnectionState.active:
         throw 'Unsupported state ${snapshot.connectionState}';
     }
   }

dev/manual_tests/lib/card_collection.dart

@@ -291,16 +291,20 @@ class CardCollectionState extends State<CardCollection> {
       case DismissDirection.startToEnd:
         backgroundMessage = 'Swipe right to dismiss';
         break;
-      default:
+      case DismissDirection.vertical:
+      case DismissDirection.up:
+      case DismissDirection.down:
+      case DismissDirection.none:
         backgroundMessage = 'Unsupported dismissDirection';
+        break;
     }
 
-    // TODO(abarth): This icon is wrong in RTL.
+    // This icon is wrong in RTL.
     Widget leftArrowIcon = const Icon(Icons.arrow_back, size: 36.0);
     if (_dismissDirection == DismissDirection.startToEnd)
       leftArrowIcon = Opacity(opacity: 0.1, child: leftArrowIcon);
 
-      // TODO(abarth): This icon is wrong in RTL.
+    // This icon is wrong in RTL.
     Widget rightArrowIcon = const Icon(Icons.arrow_forward, size: 36.0);
     if (_dismissDirection == DismissDirection.endToStart)
       rightArrowIcon = Opacity(opacity: 0.1, child: rightArrowIcon);

examples/layers/services/isolate.dart

@@ -281,7 +281,6 @@ class IsolateExampleState extends State<StatefulWidget> with SingleTickerProvide
       case CalculationState.calculating:
         return 'In Progress';
       case CalculationState.idle:
-      default:
         return 'Idle';
     }
   }

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

@@ -287,7 +287,8 @@ class _CupertinoContextMenuState extends State<CupertinoContextMenu> with Ticker
         });
         break;
 
-      default:
+      case AnimationStatus.forward:
+      case AnimationStatus.reverse:
         return;
     }
   }

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

@@ -566,7 +566,9 @@ class _PackagesViewState extends State<_PackagesView> {
                     );
                   },
                 );
-              default:
+              case ConnectionState.none:
+              case ConnectionState.active:
+              case ConnectionState.waiting:
                 return Material(
                     color: Theme.of(context).cardColor,
                     child: Column(

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

@@ -406,7 +406,10 @@ class _RenderButtonBarRow extends RenderFlex {
               case MainAxisAlignment.end:
                 childParentData.offset = Offset(constraints.maxWidth - child.size.width, currentHeight);
                 break;
-              default:
+              case MainAxisAlignment.spaceAround:
+              case MainAxisAlignment.spaceBetween:
+              case MainAxisAlignment.spaceEvenly:
+              case MainAxisAlignment.start:
                 childParentData.offset = Offset(0, currentHeight);
                 break;
             }
@@ -420,7 +423,10 @@ class _RenderButtonBarRow extends RenderFlex {
               case MainAxisAlignment.end:
                 childParentData.offset = Offset(0, currentHeight);
                 break;
-              default:
+              case MainAxisAlignment.spaceAround:
+              case MainAxisAlignment.spaceBetween:
+              case MainAxisAlignment.spaceEvenly:
+              case MainAxisAlignment.start:
                 childParentData.offset = Offset(constraints.maxWidth - child.size.width, currentHeight);
                 break;
             }

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

@@ -1654,7 +1654,10 @@ class _CalendarDateRangePickerState extends State<_CalendarDateRangePicker> {
       case TargetPlatform.fuchsia:
         HapticFeedback.vibrate();
         break;
-      default:
+      case TargetPlatform.iOS:
+      case TargetPlatform.linux:
+      case TargetPlatform.macOS:
+      case TargetPlatform.windows:
         break;
     }
   }

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

@@ -374,7 +374,8 @@ class DrawerControllerState extends State<DrawerController> with SingleTickerPro
         case AnimationStatus.dismissed:
           _controller.value = widget.isDrawerOpen ? 1.0 : 0.0;
           break;
-        default:
+        case AnimationStatus.forward:
+        case AnimationStatus.reverse:
           break;
       }
     }

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

@@ -350,7 +350,9 @@ class _MaterialState extends State<Material> with TickerProviderStateMixin {
         case MaterialType.card:
           color = theme.cardColor;
           break;
-        default:
+        case MaterialType.button:
+        case MaterialType.circle:
+        case MaterialType.transparency:
           break;
       }
     }

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

@@ -636,7 +636,10 @@ class DefaultMaterialLocalizations implements MaterialLocalizations {
         return formatDecimal(timeOfDay.hourOfPeriod == 0 ? 12 : timeOfDay.hourOfPeriod);
       case TimeOfDayFormat.HH_colon_mm:
         return _formatTwoDigitZeroPad(timeOfDay.hour);
-      default:
+      case TimeOfDayFormat.a_space_h_colon_mm:
+      case TimeOfDayFormat.frenchCanadian:
+      case TimeOfDayFormat.H_colon_mm:
+      case TimeOfDayFormat.HH_dot_mm:
          throw AssertionError('$runtimeType does not support $format.');
     }
   }

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

@@ -346,7 +346,11 @@ class RefreshIndicatorState extends State<RefreshIndicator> with TickerProviderS
         case _RefreshIndicatorMode.drag:
           _dismiss(_RefreshIndicatorMode.canceled);
           break;
-        default:
+        case _RefreshIndicatorMode.canceled:
+        case _RefreshIndicatorMode.done:
+        case _RefreshIndicatorMode.refresh:
+        case _RefreshIndicatorMode.snap:
+        case null:
           // do nothing
           break;
       }
@@ -407,14 +411,17 @@ class RefreshIndicatorState extends State<RefreshIndicator> with TickerProviderS
     setState(() {
       _mode = newMode;
     });
-    switch (_mode) {
+    switch (_mode!) {
       case _RefreshIndicatorMode.done:
         await _scaleController.animateTo(1.0, duration: _kIndicatorScaleDuration);
         break;
       case _RefreshIndicatorMode.canceled:
         await _positionController.animateTo(0.0, duration: _kIndicatorScaleDuration);
         break;
-      default:
+      case _RefreshIndicatorMode.armed:
+      case _RefreshIndicatorMode.drag:
+      case _RefreshIndicatorMode.refresh:
+      case _RefreshIndicatorMode.snap:
         assert(false);
     }
     if (mounted && _mode == newMode) {

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

@@ -100,7 +100,7 @@ class MaterialTextSelectionControls extends TextSelectionControls {
         return const Offset(_kHandleSize, 0);
       case TextSelectionHandleType.right:
         return Offset.zero;
-      default:
+      case TextSelectionHandleType.collapsed:
         return const Offset(_kHandleSize / 2, -4);
     }
   }

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

@@ -360,7 +360,9 @@ class _TooltipState extends State<Tooltip> with SingleTickerProviderStateMixin {
       case TargetPlatform.linux:
       case TargetPlatform.windows:
         return 24.0;
-      default:
+      case TargetPlatform.android:
+      case TargetPlatform.fuchsia:
+      case TargetPlatform.iOS:
         return 32.0;
     }
   }
@@ -372,7 +374,9 @@ class _TooltipState extends State<Tooltip> with SingleTickerProviderStateMixin {
       case TargetPlatform.linux:
       case TargetPlatform.windows:
         return const EdgeInsets.symmetric(horizontal: 8.0);
-      default:
+      case TargetPlatform.android:
+      case TargetPlatform.fuchsia:
+      case TargetPlatform.iOS:
         return const EdgeInsets.symmetric(horizontal: 16.0);
     }
   }
@@ -384,7 +388,9 @@ class _TooltipState extends State<Tooltip> with SingleTickerProviderStateMixin {
       case TargetPlatform.linux:
       case TargetPlatform.windows:
         return 10.0;
-      default:
+      case TargetPlatform.android:
+      case TargetPlatform.fuchsia:
+      case TargetPlatform.iOS:
         return 14.0;
     }
   }

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

@@ -1990,7 +1990,11 @@ class RenderEditable extends RenderBox with RelayoutWhenSystemFontsChangeMixin,
               _placeholderSpans[childIndex].baseline!,
             );
             break;
-          default:
+          case ui.PlaceholderAlignment.aboveBaseline:
+          case ui.PlaceholderAlignment.belowBaseline:
+          case ui.PlaceholderAlignment.bottom:
+          case ui.PlaceholderAlignment.middle:
+          case ui.PlaceholderAlignment.top:
             baselineOffset = null;
             break;
         }

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

@@ -554,7 +554,11 @@ class RenderParagraph extends RenderBox
               _placeholderSpans[childIndex].baseline!,
             );
             break;
-          default:
+          case ui.PlaceholderAlignment.aboveBaseline:
+          case ui.PlaceholderAlignment.belowBaseline:
+          case ui.PlaceholderAlignment.bottom:
+          case ui.PlaceholderAlignment.middle:
+          case ui.PlaceholderAlignment.top:
             baselineOffset = null;
             break;
         }

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

@@ -2466,7 +2466,12 @@ class RenderFittedBox extends RenderProxyBox {
     switch (fit) {
       case BoxFit.scaleDown:
         return true;
-      default:
+      case BoxFit.contain:
+      case BoxFit.cover:
+      case BoxFit.fill:
+      case BoxFit.fitHeight:
+      case BoxFit.fitWidth:
+      case BoxFit.none:
         return false;
     }
   }
@@ -2551,7 +2556,12 @@ class RenderFittedBox extends RenderProxyBox {
           final BoxConstraints sizeConstraints = constraints.loosen();
           final Size unconstrainedSize = sizeConstraints.constrainSizeAndAttemptToPreserveAspectRatio(childSize);
           return constraints.constrain(unconstrainedSize);
-        default:
+        case BoxFit.contain:
+        case BoxFit.cover:
+        case BoxFit.fill:
+        case BoxFit.fitHeight:
+        case BoxFit.fitWidth:
+        case BoxFit.none:
           return constraints.constrainSizeAndAttemptToPreserveAspectRatio(childSize);
       }
     } else {
@@ -2569,7 +2579,12 @@ class RenderFittedBox extends RenderProxyBox {
           final Size unconstrainedSize = sizeConstraints.constrainSizeAndAttemptToPreserveAspectRatio(child!.size);
           size = constraints.constrain(unconstrainedSize);
           break;
-        default:
+        case BoxFit.contain:
+        case BoxFit.cover:
+        case BoxFit.fill:
+        case BoxFit.fitHeight:
+        case BoxFit.fitWidth:
+        case BoxFit.none:
           size = constraints.constrainSizeAndAttemptToPreserveAspectRatio(child!.size);
           break;
       }

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

@@ -69,7 +69,7 @@ KeyEventResult combineKeyEventResults(Iterable<KeyEventResult> results) {
       case KeyEventResult.skipRemainingHandlers:
         hasSkipRemainingHandlers = true;
         break;
-      default:
+      case KeyEventResult.ignored:
         break;
     }
   }

packages/flutter/test/material/snack_bar_test.dart

@@ -2593,7 +2593,8 @@ Map<DismissDirection, List<Offset>> _getDragGesturesOfDismissDirections(double s
           Offset(-scaffoldWidth, 0.0), // drag to left gesture
         ];
         break;
-      default:
+      case DismissDirection.none:
+        break;
     }
   }
 

packages/flutter/test/widgets/custom_painter_test.dart

@@ -389,8 +389,24 @@ void _defineTests() {
         case SemanticsAction.setText:
           semanticsOwner.performAction(expectedId, action, 'text');
           break;
-        default:
+        case SemanticsAction.copy:
+        case SemanticsAction.customAction:
+        case SemanticsAction.cut:
+        case SemanticsAction.decrease:
+        case SemanticsAction.didGainAccessibilityFocus:
+        case SemanticsAction.didLoseAccessibilityFocus:
+        case SemanticsAction.dismiss:
+        case SemanticsAction.increase:
+        case SemanticsAction.longPress:
+        case SemanticsAction.paste:
+        case SemanticsAction.scrollDown:
+        case SemanticsAction.scrollLeft:
+        case SemanticsAction.scrollRight:
+        case SemanticsAction.scrollUp:
+        case SemanticsAction.showOnScreen:
+        case SemanticsAction.tap:
           semanticsOwner.performAction(expectedId, action);
+          break;
       }
       expect(performedActions.length, expectedLength);
       expect(performedActions.last, action);

packages/flutter/test/widgets/semantics_test.dart

@@ -493,8 +493,26 @@ void main() {
         case SemanticsAction.setText:
           semanticsOwner.performAction(expectedId, action, 'text');
           break;
-        default:
+        case SemanticsAction.copy:
+        case SemanticsAction.customAction:
+        case SemanticsAction.cut:
+        case SemanticsAction.decrease:
+        case SemanticsAction.didGainAccessibilityFocus:
+        case SemanticsAction.didLoseAccessibilityFocus:
+        case SemanticsAction.dismiss:
+        case SemanticsAction.increase:
+        case SemanticsAction.longPress:
+        case SemanticsAction.moveCursorBackwardByWord:
+        case SemanticsAction.moveCursorForwardByWord:
+        case SemanticsAction.paste:
+        case SemanticsAction.scrollDown:
+        case SemanticsAction.scrollLeft:
+        case SemanticsAction.scrollRight:
+        case SemanticsAction.scrollUp:
+        case SemanticsAction.showOnScreen:
+        case SemanticsAction.tap:
           semanticsOwner.performAction(expectedId, action);
+          break;
       }
       expect(performedActions.length, expectedLength);
       expect(performedActions.last, action);

packages/flutter_driver/lib/src/driver/vmservice_driver.dart

@@ -593,8 +593,6 @@ List<String> _timelineStreamsToString(List<TimelineStream> streams) {
       case TimelineStream.gc: return 'GC';
       case TimelineStream.isolate: return 'Isolate';
       case TimelineStream.vm: return 'VM';
-      default:
-        throw 'Unknown timeline stream $stream';
     }
   }).toList();
 }

packages/flutter_tools/lib/src/android/android_device.dart

@@ -236,9 +236,20 @@ class AndroidDevice extends Device {
         return buildMode != BuildMode.jitRelease;
       case TargetPlatform.android_x86:
         return buildMode == BuildMode.debug;
-      default:
+      case TargetPlatform.android:
+      case TargetPlatform.darwin:
+      case TargetPlatform.fuchsia_arm64:
+      case TargetPlatform.fuchsia_x64:
+      case TargetPlatform.ios:
+      case TargetPlatform.linux_arm64:
+      case TargetPlatform.linux_x64:
+      case TargetPlatform.tester:
+      case TargetPlatform.web_javascript:
+      case TargetPlatform.windows_uwp_x64:
+      case TargetPlatform.windows_x64:
         throw UnsupportedError('Invalid target platform for Android');
     }
+    throw null; // dead code, remove after null migration
   }
 
   @override
@@ -560,7 +571,17 @@ class AndroidDevice extends Device {
       case TargetPlatform.android_x86:
         androidArch = AndroidArch.x86;
         break;
-      default:
+      case TargetPlatform.android:
+      case TargetPlatform.darwin:
+      case TargetPlatform.fuchsia_arm64:
+      case TargetPlatform.fuchsia_x64:
+      case TargetPlatform.ios:
+      case TargetPlatform.linux_arm64:
+      case TargetPlatform.linux_x64:
+      case TargetPlatform.tester:
+      case TargetPlatform.web_javascript:
+      case TargetPlatform.windows_uwp_x64:
+      case TargetPlatform.windows_x64:
         _logger.printError('Android platforms are only supported.');
         return LaunchResult.failed();
     }

packages/flutter_tools/lib/src/artifacts.dart

@@ -420,10 +420,12 @@ class CachedArtifacts implements Artifacts {
   }) {
     platform = _mapTargetPlatform(platform);
     switch (platform) {
+      case TargetPlatform.android:
       case TargetPlatform.android_arm:
       case TargetPlatform.android_arm64:
       case TargetPlatform.android_x64:
       case TargetPlatform.android_x86:
+        assert(platform != TargetPlatform.android);
         return _getAndroidArtifactPath(artifact, platform!, mode!);
       case TargetPlatform.ios:
         return _getIosArtifactPath(artifact, platform!, mode, environmentType);
@@ -438,7 +440,7 @@ class CachedArtifacts implements Artifacts {
         return _getFuchsiaArtifactPath(artifact, platform!, mode!);
       case TargetPlatform.tester:
       case TargetPlatform.web_javascript:
-      default: // could be null, but that can't be specified as a case.
+      case null:
         return _getHostArtifactPath(artifact, platform ?? _currentHostPlatform(_platform, _operatingSystemUtils), mode);
     }
   }
@@ -468,7 +470,29 @@ class CachedArtifacts implements Artifacts {
         assert(mode != BuildMode.debug, 'Artifact $artifact only available in non-debug mode.');
         final String hostPlatform = getNameForHostPlatform(getCurrentHostPlatform());
         return _fileSystem.path.join(engineDir, hostPlatform, _artifactToFileName(artifact));
-      default:
+      case Artifact.constFinder:
+      case Artifact.flutterFramework:
+      case Artifact.flutterMacOSFramework:
+      case Artifact.flutterMacOSPodspec:
+      case Artifact.flutterPatchedSdkPath:
+      case Artifact.flutterTester:
+      case Artifact.flutterXcframework:
+      case Artifact.fontSubset:
+      case Artifact.fuchsiaFlutterRunner:
+      case Artifact.fuchsiaKernelCompiler:
+      case Artifact.icuData:
+      case Artifact.isolateSnapshotData:
+      case Artifact.linuxDesktopPath:
+      case Artifact.linuxHeaders:
+      case Artifact.platformKernelDill:
+      case Artifact.platformLibrariesJson:
+      case Artifact.skyEnginePath:
+      case Artifact.uwptool:
+      case Artifact.vmSnapshotData:
+      case Artifact.windowsCppClientWrapper:
+      case Artifact.windowsDesktopPath:
+      case Artifact.windowsUwpCppClientWrapper:
+      case Artifact.windowsUwpDesktopPath:
         return _getHostArtifactPath(artifact, platform, mode);
     }
   }
@@ -484,7 +508,27 @@ class CachedArtifacts implements Artifacts {
       case Artifact.flutterFramework:
         final String engineDir = _getEngineArtifactsPath(platform, mode)!;
         return _getIosEngineArtifactPath(engineDir, environmentType, _fileSystem);
-      default:
+      case Artifact.constFinder:
+      case Artifact.flutterMacOSFramework:
+      case Artifact.flutterMacOSPodspec:
+      case Artifact.flutterPatchedSdkPath:
+      case Artifact.flutterTester:
+      case Artifact.fontSubset:
+      case Artifact.fuchsiaFlutterRunner:
+      case Artifact.fuchsiaKernelCompiler:
+      case Artifact.icuData:
+      case Artifact.isolateSnapshotData:
+      case Artifact.linuxDesktopPath:
+      case Artifact.linuxHeaders:
+      case Artifact.platformKernelDill:
+      case Artifact.platformLibrariesJson:
+      case Artifact.skyEnginePath:
+      case Artifact.uwptool:
+      case Artifact.vmSnapshotData:
+      case Artifact.windowsCppClientWrapper:
+      case Artifact.windowsDesktopPath:
+      case Artifact.windowsUwpCppClientWrapper:
+      case Artifact.windowsUwpDesktopPath:
         return _getHostArtifactPath(artifact, platform, mode);
     }
   }
@@ -513,7 +557,26 @@ class CachedArtifacts implements Artifacts {
       case Artifact.fuchsiaFlutterRunner:
         final String artifactFileName = _artifactToFileName(artifact, platform, mode)!;
         return _fileSystem.path.join(root, runtime, artifactFileName);
-      default:
+      case Artifact.constFinder:
+      case Artifact.flutterFramework:
+      case Artifact.flutterMacOSFramework:
+      case Artifact.flutterMacOSPodspec:
+      case Artifact.flutterTester:
+      case Artifact.flutterXcframework:
+      case Artifact.fontSubset:
+      case Artifact.frontendServerSnapshotForEngineDartSdk:
+      case Artifact.icuData:
+      case Artifact.isolateSnapshotData:
+      case Artifact.linuxDesktopPath:
+      case Artifact.linuxHeaders:
+      case Artifact.platformLibrariesJson:
+      case Artifact.skyEnginePath:
+      case Artifact.uwptool:
+      case Artifact.vmSnapshotData:
+      case Artifact.windowsCppClientWrapper:
+      case Artifact.windowsDesktopPath:
+      case Artifact.windowsUwpCppClientWrapper:
+      case Artifact.windowsUwpDesktopPath:
         return _getHostArtifactPath(artifact, platform, mode);
     }
   }
@@ -586,7 +649,10 @@ class CachedArtifacts implements Artifacts {
                      .childDirectory('windows-uwp-x64-${getNameForBuildMode(mode ?? BuildMode.debug)}')
                      .childFile(_artifactToFileName(artifact, platform, mode)!)
                      .path;
-      default:
+      case Artifact.flutterFramework:
+      case Artifact.flutterXcframework:
+      case Artifact.fuchsiaFlutterRunner:
+      case Artifact.fuchsiaKernelCompiler:
         throw StateError('Artifact $artifact not available for platform $platform.');
     }
   }

packages/flutter_tools/lib/src/build_info.dart

@@ -718,7 +718,19 @@ String fuchsiaArchForTargetPlatform(TargetPlatform targetPlatform) {
       return 'arm64';
     case TargetPlatform.fuchsia_x64:
       return 'x64';
-    default:
+    case TargetPlatform.android:
+    case TargetPlatform.android_arm:
+    case TargetPlatform.android_arm64:
+    case TargetPlatform.android_x64:
+    case TargetPlatform.android_x86:
+    case TargetPlatform.darwin:
+    case TargetPlatform.ios:
+    case TargetPlatform.linux_arm64:
+    case TargetPlatform.linux_x64:
+    case TargetPlatform.tester:
+    case TargetPlatform.web_javascript:
+    case TargetPlatform.windows_uwp_x64:
+    case TargetPlatform.windows_x64:
       throw UnsupportedError('Unexpected Fuchsia platform $targetPlatform');
   }
 }
@@ -963,7 +975,17 @@ String getNameForTargetPlatformArch(TargetPlatform platform) {
       return 'x64';
     case TargetPlatform.linux_arm64:
       return 'arm64';
-    default:
+    case TargetPlatform.android:
+    case TargetPlatform.android_arm:
+    case TargetPlatform.android_arm64:
+    case TargetPlatform.android_x64:
+    case TargetPlatform.android_x86:
+    case TargetPlatform.fuchsia_arm64:
+    case TargetPlatform.fuchsia_x64:
+    case TargetPlatform.ios:
+    case TargetPlatform.tester:
+    case TargetPlatform.web_javascript:
+    case TargetPlatform.windows_uwp_x64:
       throw UnsupportedError('Unexpected target platform $platform');
   }
 }

packages/flutter_tools/lib/src/build_system/targets/common.dart

@@ -193,8 +193,20 @@ class KernelSnapshot extends Target {
       case TargetPlatform.linux_x64:
         forceLinkPlatform = true;
         break;
-      default:
+      case TargetPlatform.android:
+      case TargetPlatform.android_arm:
+      case TargetPlatform.android_arm64:
+      case TargetPlatform.android_x64:
+      case TargetPlatform.android_x86:
+      case TargetPlatform.fuchsia_arm64:
+      case TargetPlatform.fuchsia_x64:
+      case TargetPlatform.ios:
+      case TargetPlatform.linux_arm64:
+      case TargetPlatform.tester:
+      case TargetPlatform.web_javascript:
+      case TargetPlatform.windows_uwp_x64:
         forceLinkPlatform = false;
+        break;
     }
 
     final PackageConfig packageConfig = await loadPackageConfigWithLogging(

packages/flutter_tools/lib/src/commands/build_bundle.dart

@@ -111,16 +111,27 @@ class BuildBundleCommand extends BuildSubCommand {
         }
         break;
       case TargetPlatform.windows_x64:
+      case TargetPlatform.windows_uwp_x64:
         if (!featureFlags.isWindowsEnabled) {
           throwToolExit('Windows is not a supported target platform.');
         }
         break;
       case TargetPlatform.linux_x64:
+      case TargetPlatform.linux_arm64:
         if (!featureFlags.isLinuxEnabled) {
           throwToolExit('Linux is not a supported target platform.');
         }
         break;
-      default:
+      case TargetPlatform.android:
+      case TargetPlatform.android_arm:
+      case TargetPlatform.android_arm64:
+      case TargetPlatform.android_x64:
+      case TargetPlatform.android_x86:
+      case TargetPlatform.fuchsia_arm64:
+      case TargetPlatform.fuchsia_x64:
+      case TargetPlatform.ios:
+      case TargetPlatform.tester:
+      case TargetPlatform.web_javascript:
         break;
     }
 

packages/flutter_tools/lib/src/commands/create_base.dart

@@ -287,7 +287,7 @@ abstract class CreateBase extends FlutterCommand {
 
     final FileSystemEntityType type = globals.fs.typeSync(projectDirPath);
 
-    switch (type) {
+    switch (type) { // ignore: exhaustive_cases, https://github.com/dart-lang/linter/issues/3017
       case FileSystemEntityType.file:
         // Do not overwrite files.
         throwToolExit("Invalid project name: '$projectDirPath' - file exists.",
@@ -298,7 +298,9 @@ abstract class CreateBase extends FlutterCommand {
         throwToolExit("Invalid project name: '$projectDirPath' - refers to a link.",
             exitCode: 2);
         break;
-      default:
+      case FileSystemEntityType.directory:
+      case FileSystemEntityType.notFound:
+        break;
     }
   }
 

packages/flutter_tools/lib/src/commands/ide_config.dart

@@ -269,11 +269,14 @@ class IdeConfigCommand extends FlutterCommand {
 String _validateFlutterDir(String dirPath, { String flutterRoot }) {
   final FileSystemEntityType type = globals.fs.typeSync(dirPath);
 
-  switch (type) {
+  switch (type) { // ignore: exhaustive_cases, https://github.com/dart-lang/linter/issues/3017
     case FileSystemEntityType.link:
       // Do not overwrite links.
       return "Invalid project root dir: '$dirPath' - refers to a link.";
-    default:
+    case FileSystemEntityType.file:
+    case FileSystemEntityType.directory:
+    case FileSystemEntityType.notFound:
       return null;
   }
+  return null; // dead code, remove after null safety migration
 }

packages/flutter_tools/lib/src/commands/update_packages.dart

@@ -850,7 +850,10 @@ class PubspecYaml {
             }
             endOfDevDependencies = output.length;
             break;
-          default:
+          case Section.builders:
+          case Section.dependencyOverrides:
+          case Section.header:
+          case Section.other:
             // In other sections, pass everything through in its original form.
             output.add(data.line);
             if (data.lockLine != null) {

packages/flutter_tools/lib/src/doctor_validator.dart

@@ -126,8 +126,6 @@ class GroupedValidator extends DoctorValidator {
             mergedType = ValidationType.partial;
           }
           break;
-        default:
-          throw 'Unrecognized validation type: ${result.type}';
       }
       mergedMessages.addAll(result.messages);
     }

packages/flutter_tools/lib/src/drive/web_driver_service.dart

@@ -317,9 +317,8 @@ Map<String, dynamic> getDesiredCapabilities(Browser browser, bool headless, [Str
           'args': <String>['--disable-fullscreen']
         },
       };
-    default:
-      throw UnsupportedError('Browser $browser not supported.');
   }
+  throw UnsupportedError('Browser $browser not supported.'); // dead code; remove with null safety migration
 }
 
 /// Converts [browserName] string to [Browser]
@@ -332,5 +331,5 @@ Browser _browserNameToEnum(String browserName) {
     case 'ios-safari': return Browser.iosSafari;
     case 'safari': return Browser.safari;
   }
-  throw UnsupportedError('Browser $browserName not supported');
+  throw UnsupportedError('Browser $browserName not supported'); // dead code; remove with null safety migration
 }

packages/flutter_tools/lib/src/flutter_plugins.dart

@@ -348,7 +348,6 @@ List<Map<String, Object?>> _extractPlatformMaps(List<Plugin> plugins, String typ
 /// [project] is using.
 AndroidEmbeddingVersion _getAndroidEmbeddingVersion(FlutterProject project) {
   assert(project.android != null);
-
   return project.android.getEmbeddingVersion();
 }
 
@@ -415,7 +414,6 @@ Future<void> _writeAndroidPluginRegistrant(FlutterProject project, List<Plugin>
       templateContent = _androidPluginRegistryTemplateNewEmbedding;
       break;
     case AndroidEmbeddingVersion.v1:
-    default:
       globals.printError(
         'This app is using a deprecated version of the Android embedding.\n'
         'To avoid unexpected runtime failures, or future build failures, try to migrate this '

packages/flutter_tools/lib/src/ios/mac.dart

@@ -598,8 +598,6 @@ String xcodeBuildActionToString(XcodeBuildAction action) {
         return 'build';
       case XcodeBuildAction.archive:
         return 'archive';
-      default:
-        throw UnsupportedError('Unknown Xcode build action');
     }
 }
 

packages/flutter_tools/lib/src/mdns_discovery.dart

@@ -204,7 +204,20 @@ class MDnsObservatoryDiscovery {
           'See https://github.com/flutter/flutter/issues/46698 for details.'
         );
         break;
-      default:
+      case TargetPlatform.android:
+      case TargetPlatform.android_arm:
+      case TargetPlatform.android_arm64:
+      case TargetPlatform.android_x64:
+      case TargetPlatform.android_x86:
+      case TargetPlatform.darwin:
+      case TargetPlatform.fuchsia_arm64:
+      case TargetPlatform.fuchsia_x64:
+      case TargetPlatform.linux_arm64:
+      case TargetPlatform.linux_x64:
+      case TargetPlatform.tester:
+      case TargetPlatform.web_javascript:
+      case TargetPlatform.windows_uwp_x64:
+      case TargetPlatform.windows_x64:
         _logger.printTrace('No interface with an ipv4 link local address was found.');
         break;
     }

packages/flutter_tools/lib/src/resident_runner.dart

@@ -1467,9 +1467,19 @@ Future<String> getMissingPackageHintForPlatform(TargetPlatform platform) async {
       return 'Is your project missing an $manifestPath?\nConsider running "flutter create ." to create one.';
     case TargetPlatform.ios:
       return 'Is your project missing an ios/Runner/Info.plist?\nConsider running "flutter create ." to create one.';
-    default:
+    case TargetPlatform.android:
+    case TargetPlatform.darwin:
+    case TargetPlatform.fuchsia_arm64:
+    case TargetPlatform.fuchsia_x64:
+    case TargetPlatform.linux_arm64:
+    case TargetPlatform.linux_x64:
+    case TargetPlatform.tester:
+    case TargetPlatform.web_javascript:
+    case TargetPlatform.windows_uwp_x64:
+    case TargetPlatform.windows_x64:
       return null;
   }
+  return null; // dead code, remove after null safety migration
 }
 
 /// Redirects terminal commands to the correct resident runner methods.

packages/flutter_tools/lib/src/runner/flutter_command.dart

@@ -91,10 +91,8 @@ class FlutterCommandResult {
         return 'fail';
       case ExitStatus.killed:
         return 'killed';
-      default:
-        assert(false);
-        return null;
     }
+    return null; // dead code, remove with null safety migration
   }
 }
 

packages/flutter_tools/lib/src/sksl_writer.dart

@@ -47,7 +47,17 @@ Future<String> sharedSkSlWriter(Device device, Map<String, Object> data, {
     case TargetPlatform.android_x86:
       targetPlatform = TargetPlatform.android;
       break;
-    default:
+    case TargetPlatform.android:
+    case TargetPlatform.darwin:
+    case TargetPlatform.ios:
+    case TargetPlatform.fuchsia_arm64:
+    case TargetPlatform.fuchsia_x64:
+    case TargetPlatform.linux_arm64:
+    case TargetPlatform.linux_x64:
+    case TargetPlatform.tester:
+    case TargetPlatform.web_javascript:
+    case TargetPlatform.windows_uwp_x64:
+    case TargetPlatform.windows_x64:
       break;
   }
   final Map<String, Object> manifest = <String, Object>{

packages/flutter_tools/test/general.shard/plugins_test.dart

@@ -84,7 +84,8 @@ void main() {
       androidProject
         ..pluginRegistrantHost = androidDirectory.childDirectory('app')
         ..hostAppGradleRoot = androidDirectory
-        ..exists = false;
+        ..exists = false
+        ..embeddingVersion = AndroidEmbeddingVersion.v2;
 
       webProject = FakeWebProject();
       flutterProject.web = webProject;
@@ -922,7 +923,6 @@ dependencies:
       testUsingContext('Does not throw when AndroidManifest.xml is not found', () async {
         final File manifest = fs.file('AndroidManifest.xml');
         androidProject.appManifestFile = manifest;
-
         await injectPlugins(flutterProject, androidPlatform: true);
       }, overrides: <Type, Generator>{
         FileSystem: () => fs,

packages/integration_test/lib/_callback_web.dart

@@ -125,7 +125,7 @@ class WebCallbackManager implements CallbackManager {
             'message': Response.webDriverCommand(data: data).toJson(),
           };
           break;
-        default:
+        case WebDriverCommandType.ack:
           throw UnimplementedError('${command.type} is not implemented');
       }
     } else {