format initializer list of constructors (#27111)

packages/flutter/lib/src/animation/tween.dart

@@ -267,7 +267,9 @@ class Tween<T extends dynamic> extends Animatable<T> {
 /// A [Tween] that evaluates its [parent] in reverse.
 class ReverseTween<T> extends Tween<T> {
   /// Construct a [Tween] that evaluates its [parent] in reverse.
-  ReverseTween(this.parent) : assert(parent != null), super(begin: parent.end, end: parent.begin);
+  ReverseTween(this.parent)
+    : assert(parent != null),
+      super(begin: parent.end, end: parent.begin);
 
   /// This tween's value is the same as the parent's value evaluated in reverse.
   ///

packages/flutter/lib/src/animation/tween_sequence.dart

@@ -44,7 +44,9 @@ class TweenSequence<T> extends Animatable<T> {
   /// There's a small cost associated with building a `TweenSequence` so
   /// it's best to reuse one, rather than rebuilding it on every frame,
   /// when that's possible.
-  TweenSequence(List<TweenSequenceItem<T>> items) : assert(items != null), assert(items.isNotEmpty) {
+  TweenSequence(List<TweenSequenceItem<T>> items)
+      : assert(items != null),
+        assert(items.isNotEmpty) {
     _items.addAll(items);
 
     double totalWeight = 0.0;
@@ -95,7 +97,9 @@ class TweenSequenceItem<T> {
   const TweenSequenceItem({
     @required this.tween,
     @required this.weight,
-  }) : assert(tween != null), assert(weight != null), assert(weight > 0.0);
+  }) : assert(tween != null),
+       assert(weight != null),
+       assert(weight > 0.0);
 
   /// Defines the value of the [TweenSequence] for the interval within the
   /// animation's duration indicated by [weight] and this item's position

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

@@ -7,10 +7,15 @@ import 'dart:typed_data';
 
 // TODO(abarth): Consider using vector_math.
 class _Vector {
-  _Vector(int size) : _offset = 0, _length = size, _elements = Float64List(size);
+  _Vector(int size)
+    : _offset = 0,
+      _length = size,
+      _elements = Float64List(size);
 
   _Vector.fromVOL(List<double> values, int offset, int length)
-    : _offset = offset, _length = length, _elements = values;
+    : _offset = offset,
+      _length = length,
+      _elements = values;
 
   final int _offset;
 

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

@@ -330,8 +330,7 @@ class VerticalDragGestureRecognizer extends DragGestureRecognizer {
 ///    track each touch point independently.
 class HorizontalDragGestureRecognizer extends DragGestureRecognizer {
   /// Create a gesture recognizer for interactions in the horizontal axis.
-  HorizontalDragGestureRecognizer({ Object debugOwner }) :
+  HorizontalDragGestureRecognizer({ Object debugOwner }) : super(debugOwner: debugOwner);
-        super(debugOwner: debugOwner);
 
   @override
   bool _isFlingGesture(VelocityEstimate estimate) {

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

@@ -22,7 +22,8 @@ class UnderlineTabIndicator extends Decoration {
   const UnderlineTabIndicator({
     this.borderSide = const BorderSide(width: 2.0, color: Colors.white),
     this.insets = EdgeInsets.zero,
-  }) : assert(borderSide != null), assert(insets != null);
+  }) : assert(borderSide != null),
+       assert(insets != null);
 
   /// The color and weight of the horizontal line drawn below the selected tab.
   final BorderSide borderSide;
@@ -64,7 +65,8 @@ class UnderlineTabIndicator extends Decoration {
 
 class _UnderlinePainter extends BoxPainter {
   _UnderlinePainter(this.decoration, VoidCallback onChanged)
-    : assert(decoration != null), super(onChanged);
+    : assert(decoration != null),
+      super(onChanged);
 
   final UnderlineTabIndicator decoration;
 

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

@@ -1236,7 +1236,10 @@ class TabPageSelectorIndicator extends StatelessWidget {
     @required this.backgroundColor,
     @required this.borderColor,
     @required this.size,
-  }) : assert(backgroundColor != null), assert(borderColor != null), assert(size != null), super(key: key);
+  }) : assert(backgroundColor != null),
+       assert(borderColor != null),
+       assert(size != null),
+       super(key: key);
 
   /// The indicator circle's background color.
   final Color backgroundColor;
@@ -1275,7 +1278,8 @@ class TabPageSelector extends StatelessWidget {
     this.indicatorSize = 12.0,
     this.color,
     this.selectedColor,
-  }) : assert(indicatorSize != null && indicatorSize > 0.0), super(key: key);
+  }) : assert(indicatorSize != null && indicatorSize > 0.0),
+       super(key: key);
 
   /// This widget's selection and animation state.
   ///

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

@@ -57,7 +57,9 @@ class TimeOfDay {
   ///
   /// The [hour] is set to the time's hour and the [minute] is set to the time's
   /// minute in the timezone of the given [DateTime].
-  TimeOfDay.fromDateTime(DateTime time) : hour = time.hour, minute = time.minute;
+  TimeOfDay.fromDateTime(DateTime time)
+    : hour = time.hour,
+      minute = time.minute;
 
   /// Creates a time of day based on the current time.
   ///

packages/flutter/lib/src/painting/edge_insets.dart

@@ -330,7 +330,10 @@ class EdgeInsets extends EdgeInsetsGeometry {
   /// ```
   /// {@end-tool}
   const EdgeInsets.all(double value)
-      : left = value, top = value, right = value, bottom = value;
+    : left = value,
+      top = value,
+      right = value,
+      bottom = value;
 
   /// Creates insets with only the given values non-zero.
   ///
@@ -359,9 +362,13 @@ class EdgeInsets extends EdgeInsetsGeometry {
   /// const EdgeInsets.symmetric(vertical: 8.0)
   /// ```
   /// {@end-tool}
-  const EdgeInsets.symmetric({ double vertical = 0.0,
+  const EdgeInsets.symmetric({
-                             double horizontal = 0.0 })
+    double vertical = 0.0,
-    : left = horizontal, top = vertical, right = horizontal, bottom = vertical;
+    double horizontal = 0.0,
+  }) : left = horizontal,
+       top = vertical,
+       right = horizontal,
+       bottom = vertical;
 
   /// Creates insets that match the given window padding.
   ///

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

@@ -323,7 +323,8 @@ class TextureLayer extends Layer {
     @required this.rect,
     @required this.textureId,
     this.freeze = false,
-  }): assert(rect != null), assert(textureId != null);
+  }) : assert(rect != null),
+       assert(textureId != null);
 
   /// Bounding rectangle of this layer.
   final Rect rect;
@@ -366,7 +367,8 @@ class PlatformViewLayer extends Layer {
   PlatformViewLayer({
     @required this.rect,
     @required this.viewId,
-  }): assert(rect != null), assert(viewId != null);
+  }) : assert(rect != null),
+       assert(viewId != null);
 
   /// Bounding rectangle of this layer in the global coordinate space.
   final Rect rect;
@@ -815,9 +817,13 @@ class ClipRectLayer extends ContainerLayer {
   ///
   /// The [clipRect] property must be non-null before the compositing phase of
   /// the pipeline.
-  ClipRectLayer({ @required Rect clipRect, Clip clipBehavior = Clip.hardEdge }) :
+  ClipRectLayer({
-        _clipRect = clipRect, _clipBehavior = clipBehavior,
+    @required Rect clipRect,
-        assert(clipBehavior != null), assert(clipBehavior != Clip.none);
+    Clip clipBehavior = Clip.hardEdge,
+  }) : _clipRect = clipRect,
+       _clipBehavior = clipBehavior,
+       assert(clipBehavior != null),
+       assert(clipBehavior != Clip.none);
 
   /// The rectangle to clip in the parent's coordinate system.
   ///
@@ -887,9 +893,13 @@ class ClipRRectLayer extends ContainerLayer {
   ///
   /// The [clipRRect] property must be non-null before the compositing phase of
   /// the pipeline.
-  ClipRRectLayer({ @required RRect clipRRect, Clip clipBehavior = Clip.antiAlias }) :
+  ClipRRectLayer({
-        _clipRRect = clipRRect, _clipBehavior = clipBehavior,
+    @required RRect clipRRect,
-        assert(clipBehavior != null), assert(clipBehavior != Clip.none);
+    Clip clipBehavior = Clip.antiAlias,
+  }) : _clipRRect = clipRRect,
+       _clipBehavior = clipBehavior,
+       assert(clipBehavior != null),
+       assert(clipBehavior != Clip.none);
 
   /// The rounded-rect to clip in the parent's coordinate system.
   ///
@@ -955,9 +965,13 @@ class ClipPathLayer extends ContainerLayer {
   ///
   /// The [clipPath] property must be non-null before the compositing phase of
   /// the pipeline.
-  ClipPathLayer({ @required Path clipPath, Clip clipBehavior = Clip.antiAlias }) :
+  ClipPathLayer({
-        _clipPath = clipPath, _clipBehavior = clipBehavior,
+    @required Path clipPath,
-        assert(clipBehavior != null), assert(clipBehavior != Clip.none);
+    Clip clipBehavior = Clip.antiAlias,
+  }) : _clipPath = clipPath,
+       _clipBehavior = clipBehavior,
+       assert(clipBehavior != null),
+       assert(clipBehavior != Clip.none);
 
   /// The path to clip in the parent's coordinate system.
   ///
@@ -1094,8 +1108,11 @@ class OpacityLayer extends ContainerLayer {
   ///
   /// The [alpha] property must be non-null before the compositing phase of
   /// the pipeline.
-  OpacityLayer({ @required int alpha, Offset offset = Offset.zero })
+  OpacityLayer({
-      : _alpha = alpha, _offset = offset;
+    @required int alpha,
+    Offset offset = Offset.zero,
+  }) : _alpha = alpha,
+       _offset = offset;
 
   /// The amount to multiply into the alpha channel.
   ///
@@ -1152,8 +1169,13 @@ class ShaderMaskLayer extends ContainerLayer {
   ///
   /// The [shader], [maskRect], and [blendMode] properties must be non-null
   /// before the compositing phase of the pipeline.
-  ShaderMaskLayer({ @required Shader shader, @required Rect maskRect, @required BlendMode blendMode })
+  ShaderMaskLayer({
-      : _shader = shader, _maskRect = maskRect, _blendMode = blendMode;
+    @required Shader shader,
+    @required Rect maskRect,
+    @required BlendMode blendMode,
+  }) : _shader = shader,
+       _maskRect = maskRect,
+       _blendMode = blendMode;
 
   /// The shader to apply to the children.
   ///

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

@@ -1153,7 +1153,9 @@ abstract class _RenderCustomClip<T> extends RenderProxyBox {
     RenderBox child,
     CustomClipper<T> clipper,
     this.clipBehavior = Clip.antiAlias,
-  }) : _clipper = clipper, assert(clipBehavior != null), super(child);
+  }) : _clipper = clipper,
+       assert(clipBehavior != null),
+       super(child);
 
   /// If non-null, determines which clip to use on the child.
   CustomClipper<T> get clipper => _clipper;
@@ -1318,7 +1320,9 @@ class RenderClipRRect extends _RenderCustomClip<RRect> {
     BorderRadius borderRadius = BorderRadius.zero,
     CustomClipper<RRect> clipper,
     Clip clipBehavior = Clip.antiAlias,
-  }) : assert(clipBehavior != Clip.none), _borderRadius = borderRadius, super(child: child, clipper: clipper, clipBehavior: clipBehavior) {
+  }) : assert(clipBehavior != Clip.none),
+       _borderRadius = borderRadius,
+       super(child: child, clipper: clipper, clipBehavior: clipBehavior) {
     assert(_borderRadius != null || clipper != null);
   }
 
@@ -1389,7 +1393,8 @@ class RenderClipOval extends _RenderCustomClip<Rect> {
     RenderBox child,
     CustomClipper<Rect> clipper,
     Clip clipBehavior = Clip.antiAlias,
-  }) : assert(clipBehavior != Clip.none), super(child: child, clipper: clipper, clipBehavior: clipBehavior);
+  }) : assert(clipBehavior != Clip.none),
+       super(child: child, clipper: clipper, clipBehavior: clipBehavior);
 
   Rect _cachedRect;
   Path _cachedPath;
@@ -1464,7 +1469,8 @@ class RenderClipPath extends _RenderCustomClip<Path> {
     RenderBox child,
     CustomClipper<Path> clipper,
     Clip clipBehavior = Clip.antiAlias,
-  }) : assert(clipBehavior != Clip.none), super(child: child, clipper: clipper, clipBehavior: clipBehavior);
+  }) : assert(clipBehavior != Clip.none),
+       super(child: child, clipper: clipper, clipBehavior: clipBehavior);
 
   @override
   Path get _defaultClip => Path()..addRect(Offset.zero & size);
@@ -2878,7 +2884,9 @@ class RenderIgnorePointer extends RenderProxyBox {
     RenderBox child,
     bool ignoring = true,
     bool ignoringSemantics
-  }) : _ignoring = ignoring, _ignoringSemantics = ignoringSemantics, super(child) {
+  }) : _ignoring = ignoring,
+       _ignoringSemantics = ignoringSemantics,
+       super(child) {
     assert(_ignoring != null);
   }
 
@@ -4381,7 +4389,11 @@ class RenderSemanticsAnnotations extends RenderProxyBox {
 class RenderBlockSemantics extends RenderProxyBox {
   /// Create a render object that blocks semantics for nodes below it in paint
   /// order.
-  RenderBlockSemantics({ RenderBox child, bool blocking = true, }) : _blocking = blocking, super(child);
+  RenderBlockSemantics({
+    RenderBox child,
+    bool blocking = true,
+  }) : _blocking = blocking,
+       super(child);
 
   /// Whether this render object is blocking semantics of previously painted
   /// [RenderObject]s below a common semantics boundary from the semantic tree.
@@ -4440,7 +4452,8 @@ class RenderExcludeSemantics extends RenderProxyBox {
   RenderExcludeSemantics({
     RenderBox child,
     bool excluding = true,
-  }) : _excluding = excluding, super(child) {
+  }) : _excluding = excluding,
+       super(child) {
     assert(_excluding != null);
   }
 

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

@@ -297,7 +297,8 @@ class RenderSliverFixedExtentList extends RenderSliverFixedExtentBoxAdaptor {
   RenderSliverFixedExtentList({
     @required RenderSliverBoxChildManager childManager,
     double itemExtent,
-  }) : _itemExtent = itemExtent, super(childManager: childManager);
+  }) : _itemExtent = itemExtent,
+       super(childManager: childManager);
 
   @override
   double get itemExtent => _itemExtent;

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

@@ -356,7 +356,8 @@ abstract class RenderSliverFloatingPersistentHeader extends RenderSliverPersiste
   RenderSliverFloatingPersistentHeader({
     RenderBox child,
     FloatingHeaderSnapConfiguration snapConfiguration,
-  }) : _snapConfiguration = snapConfiguration, super(child: child);
+  }) : _snapConfiguration = snapConfiguration,
+       super(child: child);
 
   AnimationController _controller;
   Animation<double> _animation;

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

@@ -630,7 +630,8 @@ class RenderIndexedStack extends RenderStack {
     AlignmentGeometry alignment = AlignmentDirectional.topStart,
     TextDirection textDirection,
     int index = 0,
-  }) : _index = index, super(
+  }) : _index = index,
+       super(
          children: children,
          alignment: alignment,
          textDirection: textDirection,

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

@@ -36,7 +36,9 @@ import 'object.dart';
 ///    for how to create and manage backend textures on iOS.
 class TextureBox extends RenderBox {
   /// Creates a box backed by the texture identified by [textureId].
-  TextureBox({ @required int textureId }) : assert(textureId != null), _textureId = textureId;
+  TextureBox({ @required int textureId })
+    : assert(textureId != null),
+      _textureId = textureId;
 
   /// The identity of the backend texture.
   int get textureId => _textureId;

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

@@ -90,7 +90,8 @@ class RevealedOffset {
   const RevealedOffset({
     @required this.offset,
     @required this.rect,
-  }) : assert(offset != null), assert(rect != null);
+  }) : assert(offset != null),
+       assert(rect != null);
 
   /// Offset for the viewport to reveal a specific element in the viewport.
   ///

packages/flutter/lib/src/semantics/semantics_event.dart

@@ -65,8 +65,8 @@ abstract class SemanticsEvent {
 class AnnounceSemanticsEvent extends SemanticsEvent {
 
   /// Constructs an event that triggers an announcement by the platform.
-  const AnnounceSemanticsEvent(this.message, this.textDirection) :
+  const AnnounceSemanticsEvent(this.message, this.textDirection)
-    assert(message != null),
+    : assert(message != null),
       assert(textDirection != null),
       super('announce');
 

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

@@ -119,7 +119,10 @@ class TextSelection extends TextRange {
   const TextSelection.collapsed({
     @required int offset,
     this.affinity = TextAffinity.downstream
-  }) : baseOffset = offset, extentOffset = offset, isDirectional = false, super.collapsed(offset);
+  }) : baseOffset = offset,
+       extentOffset = offset,
+       isDirectional = false,
+       super.collapsed(offset);
 
   /// Creates a collapsed selection at the given text position.
   ///

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

@@ -60,8 +60,8 @@ typedef TextInputFormatFunction = TextEditingValue Function(
 
 /// Wiring for [TextInputFormatter.withFunction].
 class _SimpleTextInputFormatter extends TextInputFormatter {
-  _SimpleTextInputFormatter(this.formatFunction) :
+  _SimpleTextInputFormatter(this.formatFunction)
-    assert(formatFunction != null);
+    : assert(formatFunction != null);
 
   final TextInputFormatFunction formatFunction;
 
@@ -215,8 +215,8 @@ class WhitelistingTextInputFormatter extends TextInputFormatter {
   /// Creates a formatter that allows only the insertion of whitelisted characters patterns.
   ///
   /// The [whitelistedPattern] must not be null.
-  WhitelistingTextInputFormatter(this.whitelistedPattern) :
+  WhitelistingTextInputFormatter(this.whitelistedPattern)
-    assert(whitelistedPattern != null);
+    : assert(whitelistedPattern != null);
 
   /// A [Pattern] to extract all instances of allowed characters.
   ///

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

@@ -23,7 +23,9 @@ export 'dart:ui' show TextAffinity;
 /// for additional flags for some input types. For example, numeric input
 /// can specify whether it supports decimal numbers and/or signed numbers.
 class TextInputType {
-  const TextInputType._(this.index) : signed = null, decimal = null;
+  const TextInputType._(this.index)
+    : signed = null,
+      decimal = null;
 
   /// Optimize for numerical information.
   ///

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

@@ -26,7 +26,9 @@ const Duration _kDuration = Duration(milliseconds: 300);
 class _ActiveItem implements Comparable<_ActiveItem> {
   _ActiveItem.incoming(this.controller, this.itemIndex) : removedItemBuilder = null;
   _ActiveItem.outgoing(this.controller, this.itemIndex, this.removedItemBuilder);
-  _ActiveItem.index(this.itemIndex) : controller = null, removedItemBuilder = null;
+  _ActiveItem.index(this.itemIndex)
+    : controller = null,
+      removedItemBuilder = null;
 
   final AnimationController controller;
   final AnimatedListRemovedItemBuilder removedItemBuilder;

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

@@ -3590,7 +3590,8 @@ typedef ErrorWidgetBuilder = Widget Function(FlutterErrorDetails details);
 /// information such as the stack trace for the exception.
 class ErrorWidget extends LeafRenderObjectWidget {
   /// Creates a widget that displays the given error message.
-  ErrorWidget(Object exception) : message = _stringify(exception),
+  ErrorWidget(Object exception)
+    : message = _stringify(exception),
       super(key: UniqueKey());
 
   /// The configurable factory for [ErrorWidget].
@@ -3796,7 +3797,8 @@ class StatelessElement extends ComponentElement {
 class StatefulElement extends ComponentElement {
   /// Creates an element that uses the given widget as its configuration.
   StatefulElement(StatefulWidget widget)
-    : _state = widget.createState(), super(widget) {
+      : _state = widget.createState(),
+        super(widget) {
     assert(() {
       if (!_state._debugTypesAreRight(widget)) {
         throw FlutterError(

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

@@ -83,8 +83,8 @@ class GestureRecognizerFactoryWithHandlers<T extends GestureRecognizer> extends
   /// Creates a gesture recognizer factory with the given callbacks.
   ///
   /// The arguments must not be null.
-  const GestureRecognizerFactoryWithHandlers(this._constructor, this._initializer) :
+  const GestureRecognizerFactoryWithHandlers(this._constructor, this._initializer)
-    assert(_constructor != null),
+    : assert(_constructor != null),
       assert(_initializer != null);
 
   final GestureRecognizerFactoryConstructor<T> _constructor;

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

@@ -1377,7 +1377,8 @@ class RenderSliverOverlapAbsorber extends RenderSliver with RenderObjectWithChil
   RenderSliverOverlapAbsorber({
     @required SliverOverlapAbsorberHandle handle,
     RenderSliver child,
-  }) : assert(handle != null), _handle = handle {
+  }) : assert(handle != null),
+       _handle = handle {
     this.child = child;
   }
 
@@ -1522,7 +1523,8 @@ class RenderSliverOverlapInjector extends RenderSliver {
   /// The [handle] must not be null.
   RenderSliverOverlapInjector({
     @required SliverOverlapAbsorberHandle handle,
-  }) : assert(handle != null), _handle = handle;
+  }) : assert(handle != null),
+       _handle = handle;
 
   double _currentLayoutExtent;
   double _currentMaxExtent;

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

@@ -425,7 +425,8 @@ class DragScrollActivity extends ScrollActivity {
   DragScrollActivity(
     ScrollActivityDelegate delegate,
     ScrollDragController controller,
-  ) : _controller = controller, super(delegate);
+  ) : _controller = controller,
+      super(delegate);
 
   ScrollDragController _controller;
 

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

@@ -756,7 +756,8 @@ class ListView extends BoxScrollView {
          addAutomaticKeepAlives: addAutomaticKeepAlives,
          addRepaintBoundaries: addRepaintBoundaries,
          addSemanticIndexes: addSemanticIndexes,
-       ), super(
+       ),
+       super(
          key: key,
          scrollDirection: scrollDirection,
          reverse: reverse,
@@ -820,7 +821,8 @@ class ListView extends BoxScrollView {
          addAutomaticKeepAlives: addAutomaticKeepAlives,
          addRepaintBoundaries: addRepaintBoundaries,
          addSemanticIndexes: addSemanticIndexes,
-       ), super(
+       ),
+       super(
          key: key,
          scrollDirection: scrollDirection,
          reverse: reverse,
@@ -925,7 +927,8 @@ class ListView extends BoxScrollView {
          semanticIndexCallback: (Widget _, int index) {
            return index.isEven ? index ~/ 2 : null;
          }
-       ), super(
+       ),
+       super(
          key: key,
          scrollDirection: scrollDirection,
          reverse: reverse,
@@ -1327,7 +1330,8 @@ class GridView extends BoxScrollView {
          addAutomaticKeepAlives: addAutomaticKeepAlives,
          addRepaintBoundaries: addRepaintBoundaries,
          addSemanticIndexes: addSemanticIndexes,
-       ), super(
+       ),
+       super(
          key: key,
          scrollDirection: scrollDirection,
          reverse: reverse,
@@ -1385,7 +1389,8 @@ class GridView extends BoxScrollView {
          addAutomaticKeepAlives: addAutomaticKeepAlives,
          addRepaintBoundaries: addRepaintBoundaries,
          addSemanticIndexes: addSemanticIndexes,
-       ), super(
+       ),
+       super(
          key: key,
          scrollDirection: scrollDirection,
          reverse: reverse,

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

@@ -595,7 +595,8 @@ class _ScrollSemantics extends SingleChildRenderObjectWidget {
     @required this.allowImplicitScrolling,
     @required this.semanticChildCount,
     Widget child
-  }) : assert(position != null), super(key: key, child: child);
+  }) : assert(position != null),
+       super(key: key, child: child);
 
   final ScrollPosition position;
   final bool allowImplicitScrolling;
@@ -628,7 +629,8 @@ class _RenderScrollSemantics extends RenderProxyBox {
   }) : _position = position,
        _allowImplicitScrolling = allowImplicitScrolling,
        _semanticChildCount = semanticChildCount,
-       assert(position != null), super(child) {
+       assert(position != null),
+       super(child) {
     position.addListener(markNeedsSemanticsUpdate);
   }
 

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

@@ -39,7 +39,8 @@ class SliverPrototypeExtentList extends SliverMultiBoxAdaptorWidget {
     Key key,
     @required SliverChildDelegate delegate,
     @required this.prototypeItem,
-  }) : assert(prototypeItem != null), super(key: key, delegate: delegate);
+  }) : assert(prototypeItem != null),
+       super(key: key, delegate: delegate);
 
   /// Defines the main axis extent of all of this sliver's children.
   ///

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

@@ -34,7 +34,11 @@ import 'framework.dart';
 ///    for how to create and manage backend textures on iOS.
 class Texture extends LeafRenderObjectWidget {
   /// Creates a widget backed by the texture identified by [textureId].
-  const Texture({ Key key, @required this.textureId }): assert(textureId != null), super(key: key);
+  const Texture({
+    Key key,
+    @required this.textureId,
+  }) : assert(textureId != null),
+       super(key: key);
 
   /// The identity of the backend texture.
   final int textureId;

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

@@ -607,7 +607,12 @@ class _DiagnosticsPathNode {
   /// [DiagnosticsNode] objects.
   ///
   /// The [node] and [child] arguments must not be null.
-  _DiagnosticsPathNode({ @required this.node, @required this.children, this.childIndex }) : assert(node != null), assert(children != null);
+  _DiagnosticsPathNode({
+    @required this.node,
+    @required this.children,
+    this.childIndex,
+  }) : assert(node != null),
+       assert(children != null);
 
   /// Node at the point in the path this [_DiagnosticsPathNode] is describing.
   final DiagnosticsNode node;
@@ -686,8 +691,7 @@ class _SerializeConfig {
     _SerializeConfig base, {
     int subtreeDepth,
     Iterable<Diagnosticable> pathToInclude,
-  }) :
+  }) : groupName = base.groupName,
-    groupName = base.groupName,
        summaryTree = base.summaryTree,
        subtreeDepth = subtreeDepth ?? base.subtreeDepth,
        pathToInclude = pathToInclude ?? base.pathToInclude,
@@ -2443,7 +2447,9 @@ class _InspectorOverlay extends LeafRenderObjectWidget {
 
 class _RenderInspectorOverlay extends RenderBox {
   /// The arguments must not be null.
-  _RenderInspectorOverlay({ @required InspectorSelection selection }) : _selection = selection, assert(selection != null);
+  _RenderInspectorOverlay({ @required InspectorSelection selection })
+    : _selection = selection,
+      assert(selection != null);
 
   InspectorSelection get selection => _selection;
   InspectorSelection _selection;
@@ -2476,8 +2482,8 @@ class _RenderInspectorOverlay extends RenderBox {
 }
 
 class _TransformedRect {
-  _TransformedRect(RenderObject object) :
+  _TransformedRect(RenderObject object)
-    rect = object.semanticBounds,
+    : rect = object.semanticBounds,
       transform = object.getTransformTo(null);
 
   final Rect rect;
@@ -2545,7 +2551,8 @@ class _InspectorOverlayLayer extends Layer {
   _InspectorOverlayLayer({
     @required this.overlayRect,
     @required this.selection,
-  }) : assert(overlayRect != null), assert(selection != null) {
+  }) : assert(overlayRect != null),
+       assert(selection != null) {
     bool inDebugMode = false;
     assert(() {
       inDebugMode = true;

packages/flutter/test/painting/image_stream_test.dart

@@ -11,8 +11,8 @@ import 'package:flutter/scheduler.dart' show timeDilation;
 import 'package:flutter_test/flutter_test.dart';
 
 class FakeFrameInfo implements FrameInfo {
-  FakeFrameInfo(int width, int height, this._duration) :
+  FakeFrameInfo(int width, int height, this._duration)
-    _image = FakeImage(width, height);
+    : _image = FakeImage(width, height);
 
   final Duration _duration;
   final Image _image;

packages/flutter/test/rendering/mock_canvas.dart

@@ -559,7 +559,8 @@ abstract class _TestRecordingCanvasMatcher extends Matcher {
 
 class _TestRecordingCanvasPaintsCountMatcher extends _TestRecordingCanvasMatcher {
   _TestRecordingCanvasPaintsCountMatcher(Symbol methodName, int count)
-      : _methodName = methodName, _count = count;
+    : _methodName = methodName,
+      _count = count;
 
   final Symbol _methodName;
   final int _count;

packages/flutter_test/lib/src/accessibility.dart

@@ -17,7 +17,9 @@ import 'widget_tester.dart';
 /// The result of evaluating a semantics node by a [AccessibilityGuideline].
 class Evaluation {
   /// Create a passing evaluation.
-  const Evaluation.pass() : passed = true, reason = null;
+  const Evaluation.pass()
+    : passed = true,
+      reason = null;
 
   /// Create a failing evaluation, with an optional [reason] explaining the
   /// result.

packages/flutter_test/lib/src/test_compat.dart

@@ -310,6 +310,7 @@ class _Reporter {
       _yellow = color ? '\u001b[33m' : '',
       _bold = color ? '\u001b[1m' : '',
       _noColor = color ? '\u001b[0m' : '';
+
   final List<LiveTest> passed = <LiveTest>[];
   final List<LiveTest> failed = <LiveTest>[];
   final List<Test> skipped = <Test>[];

packages/flutter_tools/lib/src/artifacts.dart

@@ -76,8 +76,10 @@ String _artifactToFileName(Artifact artifact, [TargetPlatform platform, BuildMod
 }
 
 class EngineBuildPaths {
-  const EngineBuildPaths({ @required this.targetEngine, @required this.hostEngine }):
+  const EngineBuildPaths({
-      assert(targetEngine != null),
+    @required this.targetEngine,
+    @required this.hostEngine,
+  }) : assert(targetEngine != null),
        assert(hostEngine != null);
 
   final String targetEngine;

packages/flutter_tools/lib/src/base/process.dart

@@ -361,7 +361,9 @@ class ProcessExit implements Exception {
 }
 
 class RunResult {
-  RunResult(this.processResult, this._command) : assert(_command != null), assert(_command.isNotEmpty);
+  RunResult(this.processResult, this._command)
+    : assert(_command != null),
+      assert(_command.isNotEmpty);
 
   final ProcessResult processResult;
 

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

@@ -903,7 +903,8 @@ class PubspecDependency extends PubspecLine {
     DependencyKind kind,
     this.version,
     this.sourcePath,
-  }) : _kind = kind, super(line);
+  }) : _kind = kind,
+       super(line);
 
   static PubspecDependency parse(String line, { @required String filename }) {
     // We recognize any line that:

packages/flutter_tools/lib/src/compile.dart

@@ -286,9 +286,13 @@ abstract class _CompilationRequest {
 }
 
 class _RecompileRequest extends _CompilationRequest {
-  _RecompileRequest(Completer<CompilerOutput> completer, this.mainPath,
+  _RecompileRequest(
-      this.invalidatedFiles, this.outputPath, this.packagesFilePath) :
+    Completer<CompilerOutput> completer,
-      super(completer);
+    this.mainPath,
+    this.invalidatedFiles,
+    this.outputPath,
+    this.packagesFilePath,
+  ) : super(completer);
 
   String mainPath;
   List<String> invalidatedFiles;
@@ -301,9 +305,15 @@ class _RecompileRequest extends _CompilationRequest {
 }
 
 class _CompileExpressionRequest extends _CompilationRequest {
-  _CompileExpressionRequest(Completer<CompilerOutput> completer, this.expression, this.definitions,
+  _CompileExpressionRequest(
-      this.typeDefinitions, this.libraryUri, this.klass, this.isStatic) :
+    Completer<CompilerOutput> completer,
-      super(completer);
+    this.expression,
+    this.definitions,
+    this.typeDefinitions,
+    this.libraryUri,
+    this.klass,
+    this.isStatic
+  ) : super(completer);
 
   String expression;
   List<String> definitions;

packages/flutter_tools/lib/src/dart/dependencies.dart

@@ -26,8 +26,8 @@ String _dottedNameToString(analyzer.DottedName dottedName) {
 }
 
 class DartDependencySetBuilder {
-  DartDependencySetBuilder(String mainScriptPath, String packagesFilePath) :
+  DartDependencySetBuilder(String mainScriptPath, String packagesFilePath)
-    _mainScriptPath = canonicalizePath(mainScriptPath),
+    : _mainScriptPath = canonicalizePath(mainScriptPath),
       _mainScriptUri = fs.path.toUri(mainScriptPath),
       _packagesFilePath = canonicalizePath(packagesFilePath);
 

packages/flutter_tools/lib/src/devfs.dart

@@ -193,7 +193,9 @@ class DevFSByteContent extends DevFSContent {
 
 /// String content to be copied to the device.
 class DevFSStringContent extends DevFSByteContent {
-  DevFSStringContent(String string) : _string = string, super(utf8.encode(string));
+  DevFSStringContent(String string)
+    : _string = string,
+      super(utf8.encode(string));
 
   String _string;
 
@@ -377,23 +379,23 @@ class UpdateFSReport {
 
 class DevFS {
   /// Create a [DevFS] named [fsName] for the local files in [rootDirectory].
-  DevFS(VMService serviceProtocol,
+  DevFS(
+    VMService serviceProtocol,
     this.fsName,
     this.rootDirectory, {
     String packagesFilePath
-      })
+  }) : _operations = ServiceProtocolDevFSOperations(serviceProtocol),
-    : _operations = ServiceProtocolDevFSOperations(serviceProtocol),
        _httpWriter = _DevFSHttpWriter(fsName, serviceProtocol) {
     _packagesFilePath =
         packagesFilePath ?? fs.path.join(rootDirectory.path, kPackagesFileName);
   }
 
-  DevFS.operations(this._operations,
+  DevFS.operations(
+    this._operations,
     this.fsName,
     this.rootDirectory, {
     String packagesFilePath,
-      })
+  }) : _httpWriter = null {
-    : _httpWriter = null {
        _packagesFilePath =
            packagesFilePath ?? fs.path.join(rootDirectory.path, kPackagesFileName);
   }

packages/flutter_tools/lib/src/device.dart

@@ -361,8 +361,8 @@ class DebuggingOptions {
     this.observatoryPort,
    }) : debuggingEnabled = true;
 
-  DebuggingOptions.disabled(this.buildInfo) :
+  DebuggingOptions.disabled(this.buildInfo)
-    debuggingEnabled = false,
+    : debuggingEnabled = false,
       useTestFonts = false,
       startPaused = false,
       enableSoftwareRendering = false,
@@ -387,7 +387,9 @@ class DebuggingOptions {
 
 class LaunchResult {
   LaunchResult.succeeded({ this.observatoryUri }) : started = true;
-  LaunchResult.failed() : started = false, observatoryUri = null;
+  LaunchResult.failed()
+    : started = false,
+      observatoryUri = null;
 
   bool get hasObservatory => observatoryUri != null;
 

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

@@ -111,7 +111,9 @@ class IOSDevices extends PollingDeviceDiscovery {
 }
 
 class IOSDevice extends Device {
-  IOSDevice(String id, { this.name, String sdkVersion }) : _sdkVersion = sdkVersion, super(id) {
+  IOSDevice(String id, { this.name, String sdkVersion })
+      : _sdkVersion = sdkVersion,
+        super(id) {
     _installerPath = _checkForCommand('ideviceinstaller');
     _iproxyPath = _checkForCommand('iproxy');
   }

packages/flutter_tools/lib/src/version.dart

@@ -540,7 +540,12 @@ String _shortGitRevision(String revision) {
 
 class GitTagVersion {
   const GitTagVersion(this.x, this.y, this.z, this.commits, this.hash);
-  const GitTagVersion.unknown() : x = null, y = null, z = null, commits = 0, hash = '';
+  const GitTagVersion.unknown()
+    : x = null,
+      y = null,
+      z = null,
+      commits = 0,
+      hash = '';
 
   /// The X in vX.Y.Z.
   final int x;

packages/flutter_tools/test/integration/test_driver.dart

@@ -590,8 +590,8 @@ class FlutterRunTestDriver extends FlutterTestDriver {
 }
 
 class FlutterTestTestDriver extends FlutterTestDriver {
-  FlutterTestTestDriver(Directory _projectFolder, {String logPrefix}):
+  FlutterTestTestDriver(Directory _projectFolder, {String logPrefix})
-    super(_projectFolder, logPrefix: logPrefix);
+    : super(_projectFolder, logPrefix: logPrefix);
 
   Future<void> test({
     String testFile = 'test/test.dart',

packages/fuchsia_remote_debug_protocol/lib/src/common/logging.dart

@@ -69,8 +69,7 @@ class LogMessage {
   ///
   /// When this message is created, it sets its [time] to [DateTime.now].
   LogMessage(this.message, this.tag, this.level)
-      : levelName =
+    : levelName = level.toString().substring(level.toString().indexOf('.') + 1),
-            level.toString().substring(level.toString().indexOf('.') + 1),
       time = DateTime.now();
 
   /// The actual log message.