Refactoring `if` chains into `switch` statements (#144905)

Based on issue #144903, this PR aims to bring the codebase more in line with the [Flutter repo style guide](https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo#avoid-using-if-chains-or--or--with-enum-values):

> #### Avoid using `if` chains or `?:` or `==` with enum values

<br>

This change unfortunately increases the total line length, but it also improves readability.

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

@@ -40,14 +40,15 @@ class NavigationIconView {
 
   FadeTransition transition(BottomNavigationBarType type, BuildContext context) {
     Color? iconColor;
-    if (type == BottomNavigationBarType.shifting) {
+    switch (type) {
+      case BottomNavigationBarType.shifting:
         iconColor = _color;
-    } else {
+      case BottomNavigationBarType.fixed:
         final ThemeData theme = Theme.of(context);
-      final ColorScheme colorScheme = theme.colorScheme;
-      iconColor = theme.brightness == Brightness.light
-          ? colorScheme.primary
-          : colorScheme.secondary;
+        iconColor = switch (theme.brightness) {
+          Brightness.light => theme.colorScheme.primary,
+          Brightness.dark  => theme.colorScheme.secondary,
+        };
     }
 
     return FadeTransition(

dev/manual_tests/lib/overlay_geometry.dart

@@ -37,13 +37,16 @@ class _MarkerPainter extends CustomPainter {
       ..color = const Color(0xFFFFFFFF)
       ..style = PaintingStyle.stroke
       ..strokeWidth = 1.0;
-    if (type == MarkerType.topLeft) {
+
+    switch (type) {
+      case MarkerType.topLeft:
         canvas.drawLine(Offset(r, r), Offset(r + r - 1.0, r), paint);
         canvas.drawLine(Offset(r, r), Offset(r, r + r - 1.0), paint);
-    }
-    if (type == MarkerType.bottomRight) {
+      case MarkerType.bottomRight:
         canvas.drawLine(Offset(r, r), Offset(1.0, r), paint);
         canvas.drawLine(Offset(r, r), Offset(r, 1.0), paint);
+      case MarkerType.touch:
+        break;
     }
   }
 

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

@@ -41,10 +41,12 @@ class _BottomAppBarDemoState extends State<BottomAppBarDemo> {
       _isVisible ? FloatingActionButtonLocation.endContained : FloatingActionButtonLocation.endFloat;
 
   void _listen() {
-    final ScrollDirection direction = _controller.position.userScrollDirection;
-    if (direction == ScrollDirection.forward) {
+    switch (_controller.position.userScrollDirection) {
+      case ScrollDirection.idle:
+        break;
+      case ScrollDirection.forward:
         _show();
-    } else if (direction == ScrollDirection.reverse) {
+      case ScrollDirection.reverse:
         _hide();
     }
   }

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

@@ -1021,11 +1021,13 @@ class _CupertinoDatePickerDateTimeState extends State<CupertinoDatePicker> {
 
     // Adds am/pm column if the picker is not using 24h format.
     if (!widget.use24hFormat) {
-      if (localizations.datePickerDateTimeOrder == DatePickerDateTimeOrder.date_time_dayPeriod
-        || localizations.datePickerDateTimeOrder == DatePickerDateTimeOrder.time_dayPeriod_date) {
+      switch (localizations.datePickerDateTimeOrder) {
+        case DatePickerDateTimeOrder.date_time_dayPeriod:
+        case DatePickerDateTimeOrder.time_dayPeriod_date:
           pickerBuilders.add(_buildAmPmPicker);
           columnWidths.add(_getEstimatedColumnWidth(_PickerColumnType.dayPeriod));
-      } else {
+        case DatePickerDateTimeOrder.date_dayPeriod_time:
+        case DatePickerDateTimeOrder.dayPeriod_time_date:
           pickerBuilders.insert(0, _buildAmPmPicker);
           columnWidths.insert(0, _getEstimatedColumnWidth(_PickerColumnType.dayPeriod));
       }
@@ -1033,11 +1035,13 @@ class _CupertinoDatePickerDateTimeState extends State<CupertinoDatePicker> {
 
     // Adds medium date column if the picker's mode is date and time.
     if (widget.mode == CupertinoDatePickerMode.dateAndTime) {
-      if (localizations.datePickerDateTimeOrder == DatePickerDateTimeOrder.time_dayPeriod_date
-          || localizations.datePickerDateTimeOrder == DatePickerDateTimeOrder.dayPeriod_time_date) {
+      switch (localizations.datePickerDateTimeOrder) {
+        case DatePickerDateTimeOrder.time_dayPeriod_date:
+        case DatePickerDateTimeOrder.dayPeriod_time_date:
           pickerBuilders.add(_buildMediumDatePicker);
           columnWidths.add(_getEstimatedColumnWidth(_PickerColumnType.date));
-      } else {
+        case DatePickerDateTimeOrder.date_time_dayPeriod:
+        case DatePickerDateTimeOrder.date_dayPeriod_time:
           pickerBuilders.insert(0, _buildMediumDatePicker);
           columnWidths.insert(0, _getEstimatedColumnWidth(_PickerColumnType.date));
       }

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

@@ -210,8 +210,9 @@ class CupertinoFormSection extends StatelessWidget {
             ),
             child: footer!);
 
-    return _type == CupertinoListSectionType.base
-        ? CupertinoListSection(
+    switch (_type) {
+      case CupertinoListSectionType.base:
+        return CupertinoListSection(
           header: headerWidget,
           footer: footerWidget,
           margin: margin,
@@ -219,8 +220,10 @@ class CupertinoFormSection extends StatelessWidget {
           decoration: decoration,
           clipBehavior: clipBehavior,
           hasLeading: false,
-            children: children)
-        : CupertinoListSection.insetGrouped(
+          children: children,
+        );
+      case CupertinoListSectionType.insetGrouped:
+        return CupertinoListSection.insetGrouped(
           header: headerWidget,
           footer: footerWidget,
           margin: margin,
@@ -228,6 +231,8 @@ class CupertinoFormSection extends StatelessWidget {
           decoration: decoration,
           clipBehavior: clipBehavior,
           hasLeading: false,
-            children: children);
+          children: children,
+        );
+    }
   }
 }

packages/flutter/lib/src/gestures/arena.dart

@@ -222,22 +222,23 @@ class GestureArenaManager {
     if (state == null) {
       return; // This arena has already resolved.
     }
-    assert(_debugLogDiagnostic(pointer, '${ disposition == GestureDisposition.accepted ? "Accepting" : "Rejecting" }: $member'));
     assert(state.members.contains(member));
-    if (disposition == GestureDisposition.rejected) {
-      state.members.remove(member);
-      member.rejectGesture(pointer);
-      if (!state.isOpen) {
-        _tryToResolveArena(pointer, state);
-      }
-    } else {
-      assert(disposition == GestureDisposition.accepted);
+    switch (disposition) {
+      case GestureDisposition.accepted:
+        assert(_debugLogDiagnostic(pointer, 'Accepting: $member'));
         if (state.isOpen) {
           state.eagerWinner ??= member;
         } else {
           assert(_debugLogDiagnostic(pointer, 'Self-declared winner: $member'));
           _resolveInFavorOf(pointer, state, member);
         }
+      case GestureDisposition.rejected:
+        assert(_debugLogDiagnostic(pointer, 'Rejecting: $member'));
+        state.members.remove(member);
+        member.rejectGesture(pointer);
+        if (!state.isOpen) {
+          _tryToResolveArena(pointer, state);
+        }
     }
   }
 

packages/flutter/lib/src/gestures/monodrag.dart

@@ -349,7 +349,8 @@ abstract class DragGestureRecognizer extends OneSequenceGestureRecognizer {
 
   void _addPointer(PointerEvent event) {
     _velocityTrackers[event.pointer] = velocityTrackerBuilder(event);
-    if (_state == _DragState.ready) {
+    switch (_state) {
+      case _DragState.ready:
         _state = _DragState.possible;
         _initialPosition = OffsetPair(global: event.position, local: event.localPosition);
         _finalPosition = _initialPosition;
@@ -358,7 +359,9 @@ abstract class DragGestureRecognizer extends OneSequenceGestureRecognizer {
         _lastPendingEventTimestamp = event.timeStamp;
         _lastTransform = event.transform;
         _checkDown();
-    } else if (_state == _DragState.accepted) {
+      case _DragState.possible:
+        break;
+      case _DragState.accepted:
         resolve(GestureDisposition.accepted);
     }
   }
@@ -421,15 +424,8 @@ abstract class DragGestureRecognizer extends OneSequenceGestureRecognizer {
       final Offset position = (event is PointerMoveEvent) ? event.position : (event.position + (event as PointerPanZoomUpdateEvent).pan);
       final Offset localPosition = (event is PointerMoveEvent) ? event.localPosition : (event.localPosition + (event as PointerPanZoomUpdateEvent).localPan);
       _finalPosition = OffsetPair(local: localPosition, global: position);
-      if (_state == _DragState.accepted) {
-        _checkUpdate(
-          sourceTimeStamp: event.timeStamp,
-          delta: _getDeltaForDetails(localDelta),
-          primaryDelta: _getPrimaryValueFromOffset(localDelta),
-          globalPosition: position,
-          localPosition: localPosition,
-        );
-      } else {
+      switch (_state) {
+        case _DragState.ready || _DragState.possible:
           _pendingDragOffset += OffsetPair(local: localDelta, global: delta);
           _lastPendingEventTimestamp = event.timeStamp;
           _lastTransform = event.transform;
@@ -448,9 +444,17 @@ abstract class DragGestureRecognizer extends OneSequenceGestureRecognizer {
               resolve(GestureDisposition.accepted);
             }
           }
+        case _DragState.accepted:
+          _checkUpdate(
+            sourceTimeStamp: event.timeStamp,
+            delta: _getDeltaForDetails(localDelta),
+            primaryDelta: _getPrimaryValueFromOffset(localDelta),
+            globalPosition: position,
+            localPosition: localPosition,
+          );
       }
     }
-    if (event is PointerUpEvent || event is PointerCancelEvent || event is PointerPanZoomEndEvent) {
+    if (event case PointerUpEvent() || PointerCancelEvent() || PointerPanZoomEndEvent()) {
       _giveUpPointer(event.pointer);
     }
   }

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

@@ -1152,9 +1152,10 @@ class _MasterDetailFlowState extends State<_MasterDetailFlow> implements _PageOp
   @override
   void openDetailPage(Object arguments) {
     _cachedDetailArguments = arguments;
-    if (_builtLayout == _LayoutMode.nested) {
+    switch (_builtLayout) {
+      case _LayoutMode.nested:
         _navigatorKey.currentState!.pushNamed(_navDetail, arguments: arguments);
-    } else {
+      case _LayoutMode.lateral || null:
         focus = _Focus.detail;
     }
   }

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

@@ -455,19 +455,35 @@ class ToggleButtons extends StatelessWidget {
   // Determines if this is the first child that is being laid out
   // by the render object, _not_ the order of the children in its list.
   bool _isFirstButton(int index, int length, TextDirection textDirection) {
-    return index == 0 && ((direction == Axis.horizontal && textDirection == TextDirection.ltr) ||
-      (direction == Axis.vertical && verticalDirection == VerticalDirection.down))
-      || index == length - 1 && ((direction == Axis.horizontal && textDirection == TextDirection.rtl) ||
-      (direction == Axis.vertical && verticalDirection == VerticalDirection.up));
+    switch (direction) {
+      case Axis.horizontal:
+        return switch (textDirection) {
+          TextDirection.rtl => index == length - 1,
+          TextDirection.ltr => index == 0,
+        };
+      case Axis.vertical:
+        return switch (verticalDirection) {
+          VerticalDirection.up   => index == length - 1,
+          VerticalDirection.down => index == 0,
+        };
+    }
   }
 
   // Determines if this is the last child that is being laid out
   // by the render object, _not_ the order of the children in its list.
   bool _isLastButton(int index, int length, TextDirection textDirection) {
-    return index == length - 1 && ((direction == Axis.horizontal && textDirection == TextDirection.ltr) ||
-      (direction == Axis.vertical && verticalDirection == VerticalDirection.down))
-      || index == 0 && ((direction == Axis.horizontal && textDirection == TextDirection.rtl) ||
-      (direction == Axis.vertical && verticalDirection == VerticalDirection.up));
+    switch (direction) {
+      case Axis.horizontal:
+        return switch (textDirection) {
+          TextDirection.rtl => index == 0,
+          TextDirection.ltr => index == length - 1,
+        };
+      case Axis.vertical:
+        return switch (verticalDirection) {
+          VerticalDirection.up   => index == 0,
+          VerticalDirection.down => index == length - 1,
+        };
+    }
   }
 
   BorderRadius _getEdgeBorderRadius(

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

@@ -1795,11 +1795,12 @@ class TextInput {
 
   Future<dynamic> _handleTextInputInvocation(MethodCall methodCall) async {
     final String method = methodCall.method;
-    if (method == 'TextInputClient.focusElement') {
+    switch (methodCall.method) {
+      case 'TextInputClient.focusElement':
         final List<dynamic> args = methodCall.arguments as List<dynamic>;
         _scribbleClients[args[0]]?.onScribbleFocus(Offset((args[1] as num).toDouble(), (args[2] as num).toDouble()));
         return;
-    } else if (method == 'TextInputClient.requestElementsInRect') {
+      case 'TextInputClient.requestElementsInRect':
         final List<double> args = (methodCall.arguments as List<dynamic>).cast<num>().map<double>((num value) => value.toDouble()).toList();
         return _scribbleClients.keys.where((String elementIdentifier) {
           final Rect rect = Rect.fromLTWH(args[0], args[1], args[2], args[3]);
@@ -1812,10 +1813,10 @@ class TextInput {
           final Rect bounds = _scribbleClients[elementIdentifier]!.bounds;
           return <dynamic>[elementIdentifier, ...<dynamic>[bounds.left, bounds.top, bounds.width, bounds.height]];
         }).toList();
-    } else if (method == 'TextInputClient.scribbleInteractionBegan') {
+      case 'TextInputClient.scribbleInteractionBegan':
         _scribbleInProgress = true;
         return;
-    } else if (method == 'TextInputClient.scribbleInteractionFinished') {
+      case 'TextInputClient.scribbleInteractionFinished':
         _scribbleInProgress = false;
         return;
     }

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

@@ -871,7 +871,8 @@ class _InteractiveViewerState extends State<InteractiveViewer> with TickerProvid
       return;
     }
 
-    if (_gestureType == _GestureType.pan) {
+    switch (_gestureType) {
+      case _GestureType.pan:
         if (details.velocity.pixelsPerSecond.distance < kMinFlingVelocity) {
           _currentAxis = null;
           return;
@@ -902,7 +903,7 @@ class _InteractiveViewerState extends State<InteractiveViewer> with TickerProvid
         _controller.duration = Duration(milliseconds: (tFinal * 1000).round());
         _animation!.addListener(_onAnimate);
         _controller.forward();
-    } else if (_gestureType == _GestureType.scale) {
+      case _GestureType.scale:
         if (details.scaleVelocity.abs() < 0.1) {
           _currentAxis = null;
           return;
@@ -924,6 +925,8 @@ class _InteractiveViewerState extends State<InteractiveViewer> with TickerProvid
         _scaleController.duration = Duration(milliseconds: (tFinal * 1000).round());
         _scaleAnimation!.addListener(_onScaleAnimate);
         _scaleController.forward();
+      case _GestureType.rotate || null:
+        break;
     }
   }
 

packages/flutter/test/material/mergeable_material_test.dart

@@ -14,10 +14,11 @@ enum RadiusType {
 void matches(BorderRadius? borderRadius, RadiusType top, RadiusType bottom) {
   final Radius cardRadius = kMaterialEdges[MaterialType.card]!.topLeft;
 
-  if (top == RadiusType.Sharp) {
+  switch (top) {
+    case RadiusType.Sharp:
       expect(borderRadius?.topLeft, equals(Radius.zero));
       expect(borderRadius?.topRight, equals(Radius.zero));
-  } else if (top == RadiusType.Shifting) {
+    case RadiusType.Shifting:
       expect(borderRadius?.topLeft.x, greaterThan(0.0));
       expect(borderRadius?.topLeft.x, lessThan(cardRadius.x));
       expect(borderRadius?.topLeft.y, greaterThan(0.0));
@@ -26,15 +27,16 @@ void matches(BorderRadius? borderRadius, RadiusType top, RadiusType bottom) {
       expect(borderRadius?.topRight.x, lessThan(cardRadius.x));
       expect(borderRadius?.topRight.y, greaterThan(0.0));
       expect(borderRadius?.topRight.y, lessThan(cardRadius.y));
-  } else {
+    case RadiusType.Round:
       expect(borderRadius?.topLeft, equals(cardRadius));
       expect(borderRadius?.topRight, equals(cardRadius));
   }
 
-  if (bottom == RadiusType.Sharp) {
+  switch (bottom) {
+    case RadiusType.Sharp:
       expect(borderRadius?.bottomLeft, equals(Radius.zero));
       expect(borderRadius?.bottomRight, equals(Radius.zero));
-  } else if (bottom == RadiusType.Shifting) {
+    case RadiusType.Shifting:
       expect(borderRadius?.bottomLeft.x, greaterThan(0.0));
       expect(borderRadius?.bottomLeft.x, lessThan(cardRadius.x));
       expect(borderRadius?.bottomLeft.y, greaterThan(0.0));
@@ -43,7 +45,7 @@ void matches(BorderRadius? borderRadius, RadiusType top, RadiusType bottom) {
       expect(borderRadius?.bottomRight.x, lessThan(cardRadius.x));
       expect(borderRadius?.bottomRight.y, greaterThan(0.0));
       expect(borderRadius?.bottomRight.y, lessThan(cardRadius.y));
-  } else {
+    case RadiusType.Round:
       expect(borderRadius?.bottomLeft, equals(cardRadius));
       expect(borderRadius?.bottomRight, equals(cardRadius));
   }

packages/flutter_test/lib/src/test_text_input_key_handler.dart

@@ -221,25 +221,25 @@ class MacOSTestTextInputKeyHandler extends TestTextInputKeyHandler {
 
   @override
   Future<void> handleKeyDownEvent(LogicalKeyboardKey key) async {
-    if (key == LogicalKeyboardKey.shift ||
-        key == LogicalKeyboardKey.shiftLeft ||
-        key == LogicalKeyboardKey.shiftRight) {
+    switch (key) {
+      case LogicalKeyboardKey.shift:
+      case LogicalKeyboardKey.shiftLeft:
+      case LogicalKeyboardKey.shiftRight:
         _shift = true;
-    } else if (key == LogicalKeyboardKey.alt ||
-        key == LogicalKeyboardKey.altLeft ||
-        key == LogicalKeyboardKey.altRight) {
+      case LogicalKeyboardKey.alt:
+      case LogicalKeyboardKey.altLeft:
+      case LogicalKeyboardKey.altRight:
         _alt = true;
-    } else if (key == LogicalKeyboardKey.meta ||
-        key == LogicalKeyboardKey.metaLeft ||
-        key == LogicalKeyboardKey.metaRight) {
+      case LogicalKeyboardKey.meta:
+      case LogicalKeyboardKey.metaLeft:
+      case LogicalKeyboardKey.metaRight:
         _meta = true;
-    } else if (key == LogicalKeyboardKey.control ||
-        key == LogicalKeyboardKey.controlLeft ||
-        key == LogicalKeyboardKey.controlRight) {
+      case LogicalKeyboardKey.control:
+      case LogicalKeyboardKey.controlLeft:
+      case LogicalKeyboardKey.controlRight:
         _control = true;
-    } else {
-      for (final MapEntry<SingleActivator, List<String>> entry
-          in _macOSActivatorToSelectors.entries) {
+      default:
+        for (final MapEntry<SingleActivator, List<String>> entry in _macOSActivatorToSelectors.entries) {
           final SingleActivator activator = entry.key;
           if (activator.triggers.first == key &&
               activator.shift == _shift &&
@@ -255,21 +255,22 @@ class MacOSTestTextInputKeyHandler extends TestTextInputKeyHandler {
 
   @override
   Future<void> handleKeyUpEvent(LogicalKeyboardKey key) async {
-    if (key == LogicalKeyboardKey.shift ||
-        key == LogicalKeyboardKey.shiftLeft ||
-        key == LogicalKeyboardKey.shiftRight) {
+    switch (key) {
+      case LogicalKeyboardKey.shift:
+      case LogicalKeyboardKey.shiftLeft:
+      case LogicalKeyboardKey.shiftRight:
         _shift = false;
-    } else if (key == LogicalKeyboardKey.alt ||
-        key == LogicalKeyboardKey.altLeft ||
-        key == LogicalKeyboardKey.altRight) {
+      case LogicalKeyboardKey.alt:
+      case LogicalKeyboardKey.altLeft:
+      case LogicalKeyboardKey.altRight:
         _alt = false;
-    } else if (key == LogicalKeyboardKey.meta ||
-        key == LogicalKeyboardKey.metaLeft ||
-        key == LogicalKeyboardKey.metaRight) {
+      case LogicalKeyboardKey.meta:
+      case LogicalKeyboardKey.metaLeft:
+      case LogicalKeyboardKey.metaRight:
         _meta = false;
-    } else if (key == LogicalKeyboardKey.control ||
-        key == LogicalKeyboardKey.controlLeft ||
-        key == LogicalKeyboardKey.controlRight) {
+      case LogicalKeyboardKey.control:
+      case LogicalKeyboardKey.controlLeft:
+      case LogicalKeyboardKey.controlRight:
         _control = false;
     }
   }

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

@@ -165,14 +165,15 @@ class AndroidDevices extends PollingDeviceDiscovery {
           info['model'] = cleanAdbDeviceName(model);
         }
 
-        if (deviceState == 'unauthorized') {
+        switch (deviceState) {
+          case 'unauthorized':
             diagnostics?.add(
               'Device $deviceID is not authorized.\n'
               'You might need to check your device for an authorization dialog.'
             );
-        } else if (deviceState == 'offline') {
+          case 'offline':
             diagnostics?.add('Device $deviceID is offline.');
-        } else {
+          default:
             devices?.add(AndroidDevice(
               deviceID,
               productID: info['product'],

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

@@ -866,9 +866,10 @@ void _printWarningDisabledPlatform(List<String> platforms) {
   final List<String> web = <String>[];
 
   for (final String platform in platforms) {
-    if (platform == 'web') {
+    switch (platform) {
+      case 'web':
         web.add(platform);
-    } else if (platform == 'macos' || platform == 'windows' || platform == 'linux') {
+      case 'macos' || 'windows' || 'linux':
         desktop.add(platform);
     }
   }

packages/flutter_tools/lib/src/dart/analysis.dart

@@ -152,11 +152,12 @@ class AnalysisServer {
         }
 
         if (paramsMap != null) {
-          if (event == 'server.status') {
+          switch (event) {
+            case 'server.status':
               _handleStatus(paramsMap);
-          } else if (event == 'analysis.errors') {
+            case 'analysis.errors':
               _handleAnalysisIssues(paramsMap);
-          } else if (event == 'server.error') {
+            case 'server.error':
               _handleServerError(paramsMap);
           }
         }

packages/flutter_tools/lib/src/resident_runner.dart

@@ -120,18 +120,22 @@ class FlutterDevice {
       // TODO(zanderso): consistently provide these flags across platforms.
       final String platformDillName;
       final List<String> extraFrontEndOptions = List<String>.of(buildInfo.extraFrontEndOptions);
-      if (buildInfo.nullSafetyMode == NullSafetyMode.unsound) {
+      switch (buildInfo.nullSafetyMode) {
+        case NullSafetyMode.unsound:
           platformDillName = 'ddc_outline.dill';
           if (!extraFrontEndOptions.contains('--no-sound-null-safety')) {
             extraFrontEndOptions.add('--no-sound-null-safety');
           }
-      } else if (buildInfo.nullSafetyMode == NullSafetyMode.sound) {
+        case NullSafetyMode.sound:
           platformDillName = 'ddc_outline_sound.dill';
           if (!extraFrontEndOptions.contains('--sound-null-safety')) {
             extraFrontEndOptions.add('--sound-null-safety');
           }
-      } else {
-        throw StateError('Expected buildInfo.nullSafetyMode to be one of unsound or sound, got ${buildInfo.nullSafetyMode}');
+        case NullSafetyMode.autodetect:
+          throw StateError(
+            'Expected buildInfo.nullSafetyMode to be one of unsound or sound, '
+            'got NullSafetyMode.autodetect',
+          );
       }
 
       final String platformDillPath = globals.fs.path.join(

packages/flutter_tools/lib/src/run_hot.dart

@@ -146,16 +146,17 @@ class HotRunner extends ResidentRunner {
       return;
     }
 
-    if (flutterDevices.length == 1) {
+    switch (flutterDevices.length) {
+      case 1:
         final Device device = flutterDevices.first.device!;
         _targetPlatform = getNameForTargetPlatform(await device.targetPlatform);
         _sdkName = await device.sdkNameAndVersion;
         _emulator = await device.isLocalEmulator;
-    } else if (flutterDevices.length > 1) {
+      case > 1:
         _targetPlatform = 'multiple';
         _sdkName = 'multiple';
         _emulator = false;
-    } else {
+      default:
         _targetPlatform = 'unknown';
         _sdkName = 'unknown';
         _emulator = false;

packages/flutter_tools/lib/src/test/web_test_compiler.dart

@@ -57,12 +57,13 @@ class WebTestCompiler {
     // TODO(zanderso): to support autodetect this would need to partition the source code into
     // a sound and unsound set and perform separate compilations
     final List<String> extraFrontEndOptions = List<String>.of(buildInfo.extraFrontEndOptions);
-    if (buildInfo.nullSafetyMode == NullSafetyMode.unsound || buildInfo.nullSafetyMode == NullSafetyMode.autodetect) {
+    switch (buildInfo.nullSafetyMode) {
+      case NullSafetyMode.unsound || NullSafetyMode.autodetect:
         platformDillName = 'ddc_outline.dill';
         if (!extraFrontEndOptions.contains('--no-sound-null-safety')) {
           extraFrontEndOptions.add('--no-sound-null-safety');
         }
-    } else if (buildInfo.nullSafetyMode == NullSafetyMode.sound) {
+      case NullSafetyMode.sound:
         languageVersion = currentLanguageVersion(_fileSystem, Cache.flutterRoot!);
         platformDillName = 'ddc_outline_sound.dill';
         if (!extraFrontEndOptions.contains('--sound-null-safety')) {

packages/flutter_tools/test/integration.shard/isolated/native_assets_test.dart

@@ -147,11 +147,12 @@ void main() {
           // shadow the exception we would have gotten.
           expect(stdout, isNot(contains('EXCEPTION CAUGHT BY WIDGETS LIBRARY')));
 
-          if (device == 'macos') {
+          switch (device) {
+            case 'macos':
               expectDylibIsBundledMacOS(exampleDirectory, buildMode);
-          } else if (device == 'linux') {
+            case 'linux':
               expectDylibIsBundledLinux(exampleDirectory, buildMode);
-          } else if (device == 'windows') {
+            case 'windows':
               expectDylibIsBundledWindows(exampleDirectory, buildMode);
           }
           if (device == hostOs) {
@@ -203,15 +204,16 @@ void main() {
             throw Exception('flutter build failed: ${result.exitCode}\n${result.stderr}\n${result.stdout}');
           }
 
-          if (buildSubcommand == 'macos') {
+          switch (buildSubcommand) {
+            case 'macos':
               expectDylibIsBundledMacOS(exampleDirectory, buildMode);
-          } else if (buildSubcommand == 'ios') {
+            case 'ios':
               expectDylibIsBundledIos(exampleDirectory, buildMode);
-          } else if (buildSubcommand == 'linux') {
+            case 'linux':
               expectDylibIsBundledLinux(exampleDirectory, buildMode);
-          } else if (buildSubcommand == 'windows') {
+            case 'windows':
               expectDylibIsBundledWindows(exampleDirectory, buildMode);
-          } else if (buildSubcommand == 'apk') {
+            case 'apk':
               expectDylibIsBundledAndroid(exampleDirectory, buildMode);
           }
           expectCCompilerIsConfigured(exampleDirectory);