diff --git a/packages/flutter/lib/src/animation/animation_controller.dart b/packages/flutter/lib/src/animation/animation_controller.dart
index c279f32a4c..a3b7d068fa 100644
--- a/packages/flutter/lib/src/animation/animation_controller.dart
+++ b/packages/flutter/lib/src/animation/animation_controller.dart
@@ -797,8 +797,8 @@ class _InterpolationSimulation extends Simulation {
 
 class _RepeatingSimulation extends Simulation {
   _RepeatingSimulation(double initialValue, this.min, this.max, this.reverse, Duration period)
-    : _periodInSeconds = period.inMicroseconds / Duration.microsecondsPerSecond,
-      _initialT = (max == min) ? 0.0 : (initialValue / (max - min)) * (period.inMicroseconds / Duration.microsecondsPerSecond) {
+      : _periodInSeconds = period.inMicroseconds / Duration.microsecondsPerSecond,
+        _initialT = (max == min) ? 0.0 : (initialValue / (max - min)) * (period.inMicroseconds / Duration.microsecondsPerSecond) {
     assert(_periodInSeconds > 0.0);
     assert(_initialT >= 0.0);
   }
diff --git a/packages/flutter/lib/src/animation/animations.dart b/packages/flutter/lib/src/animation/animations.dart
index 531bfbafc1..2187219743 100644
--- a/packages/flutter/lib/src/animation/animations.dart
+++ b/packages/flutter/lib/src/animation/animations.dart
@@ -493,7 +493,7 @@ class TrainHoppingAnimation extends Animation<double>
   /// can be null. If the next train is null, then this object will just proxy
   /// the first animation and never hop.
   TrainHoppingAnimation(this._currentTrain, this._nextTrain, { this.onSwitchedTrain })
-    : assert(_currentTrain != null) {
+      : assert(_currentTrain != null) {
     if (_nextTrain != null) {
       if (_currentTrain.value == _nextTrain.value) {
         _currentTrain = _nextTrain;
@@ -701,7 +701,7 @@ class AnimationMax<T extends num> extends CompoundAnimation<T> {
   ///
   /// Both arguments must be non-null. Either can be an [AnimationMax] itself
   /// to combine multiple animations.
-  AnimationMax(Animation<T> first, Animation<T> next): super(first: first, next: next);
+  AnimationMax(Animation<T> first, Animation<T> next) : super(first: first, next: next);
 
   @override
   T get value => math.max(first.value, next.value);
@@ -716,7 +716,7 @@ class AnimationMin<T extends num> extends CompoundAnimation<T> {
   ///
   /// Both arguments must be non-null. Either can be an [AnimationMin] itself
   /// to combine multiple animations.
-  AnimationMin(Animation<T> first, Animation<T> next): super(first: first, next: next);
+  AnimationMin(Animation<T> first, Animation<T> next) : super(first: first, next: next);
 
   @override
   T get value => math.min(first.value, next.value);
diff --git a/packages/flutter/lib/src/animation/curves.dart b/packages/flutter/lib/src/animation/curves.dart
index 237833b042..d5aac3d00a 100644
--- a/packages/flutter/lib/src/animation/curves.dart
+++ b/packages/flutter/lib/src/animation/curves.dart
@@ -110,9 +110,9 @@ class Interval extends Curve {
   ///
   /// The arguments must not be null.
   const Interval(this.begin, this.end, { this.curve = Curves.linear })
-      : assert(begin != null),
-        assert(end != null),
-        assert(curve != null);
+    : assert(begin != null),
+      assert(end != null),
+      assert(curve != null);
 
   /// The largest value for which this interval is 0.0.
   ///
@@ -199,10 +199,10 @@ class Cubic extends Curve {
   ///
   /// The [a], [b], [c], and [d] arguments must not be null.
   const Cubic(this.a, this.b, this.c, this.d)
-      : assert(a != null),
-        assert(b != null),
-        assert(c != null),
-        assert(d != null);
+    : assert(a != null),
+      assert(b != null),
+      assert(c != null),
+      assert(d != null);
 
   /// The x coordinate of the first control point.
   ///
diff --git a/packages/flutter/lib/src/animation/tween.dart b/packages/flutter/lib/src/animation/tween.dart
index dc378237fa..37274d81a3 100644
--- a/packages/flutter/lib/src/animation/tween.dart
+++ b/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.
   ///
diff --git a/packages/flutter/lib/src/animation/tween_sequence.dart b/packages/flutter/lib/src/animation/tween_sequence.dart
index 83aef41e5d..79ed0eb2ac 100644
--- a/packages/flutter/lib/src/animation/tween_sequence.dart
+++ b/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
diff --git a/packages/flutter/lib/src/cupertino/action_sheet.dart b/packages/flutter/lib/src/cupertino/action_sheet.dart
index 2cbbfc07fd..1158dbead6 100644
--- a/packages/flutter/lib/src/cupertino/action_sheet.dart
+++ b/packages/flutter/lib/src/cupertino/action_sheet.dart
@@ -107,10 +107,10 @@ class CupertinoActionSheet extends StatelessWidget {
     this.messageScrollController,
     this.actionScrollController,
     this.cancelButton,
-  })  : assert(actions != null || title != null || message != null || cancelButton != null,
+  }) : assert(actions != null || title != null || message != null || cancelButton != null,
           'An action sheet must have a non-null value for at least one of the following arguments: '
           'actions, title, message, or cancelButton'),
-        super(key: key);
+       super(key: key);
 
   /// An optional title of the action sheet. When the [message] is non-null,
   /// the font of the [title] is bold.
@@ -266,8 +266,8 @@ class CupertinoActionSheetAction extends StatelessWidget {
     this.isDefaultAction = false,
     this.isDestructiveAction = false,
     @required this.child,
-  })  : assert(child != null),
-        assert(onPressed != null);
+  }) : assert(child != null),
+       assert(onPressed != null);
 
   /// The callback that is called when the button is tapped.
   ///
@@ -514,9 +514,9 @@ class _RenderCupertinoAlert extends RenderBox {
     RenderBox contentSection,
     RenderBox actionsSection,
     double dividerThickness = 0.0,
-  }) :  _contentSection = contentSection,
-        _actionsSection = actionsSection,
-        _dividerThickness = dividerThickness;
+  }) : _contentSection = contentSection,
+       _actionsSection = actionsSection,
+       _dividerThickness = dividerThickness;
 
   RenderBox get contentSection => _contentSection;
   RenderBox _contentSection;
@@ -843,8 +843,8 @@ class _CupertinoAlertActionSection extends StatefulWidget {
     @required this.children,
     this.scrollController,
     this.hasCancelButton,
-  })  : assert(children != null),
-        super(key: key);
+  }) : assert(children != null),
+       super(key: key);
 
   final List<Widget> children;
 
@@ -975,9 +975,9 @@ class _CupertinoAlertActionsRenderWidget extends MultiChildRenderObjectWidget {
     @required List<Widget> actionButtons,
     double dividerThickness = 0.0,
     bool hasCancelButton = false,
-  }) :  _dividerThickness = dividerThickness,
-        _hasCancelButton = hasCancelButton,
-        super(key: key, children: actionButtons);
+  }) : _dividerThickness = dividerThickness,
+       _hasCancelButton = hasCancelButton,
+       super(key: key, children: actionButtons);
 
   final double _dividerThickness;
   final bool _hasCancelButton;
@@ -1022,8 +1022,8 @@ class _RenderCupertinoAlertActions extends RenderBox
     List<RenderBox> children,
     double dividerThickness = 0.0,
     bool hasCancelButton = false,
-  }) :  _dividerThickness = dividerThickness,
-        _hasCancelButton = hasCancelButton {
+  }) : _dividerThickness = dividerThickness,
+       _hasCancelButton = hasCancelButton {
     addAll(children);
   }
 
diff --git a/packages/flutter/lib/src/cupertino/dialog.dart b/packages/flutter/lib/src/cupertino/dialog.dart
index 9ed6a7006f..a9d40fba62 100644
--- a/packages/flutter/lib/src/cupertino/dialog.dart
+++ b/packages/flutter/lib/src/cupertino/dialog.dart
@@ -137,8 +137,8 @@ class CupertinoAlertDialog extends StatelessWidget {
     this.actions = const <Widget>[],
     this.scrollController,
     this.actionScrollController,
-  })  : assert(actions != null),
-        super(key: key);
+  }) : assert(actions != null),
+       super(key: key);
 
   /// The (optional) title of the dialog is displayed in a large font at the top
   /// of the dialog.
@@ -893,8 +893,8 @@ class _CupertinoAlertActionSection extends StatefulWidget {
     Key key,
     @required this.children,
     this.scrollController,
-  })  : assert(children != null),
-        super(key: key);
+  }) : assert(children != null),
+       super(key: key);
 
   final List<Widget> children;
 
diff --git a/packages/flutter/lib/src/cupertino/nav_bar.dart b/packages/flutter/lib/src/cupertino/nav_bar.dart
index ef352a4644..e7029dd596 100644
--- a/packages/flutter/lib/src/cupertino/nav_bar.dart
+++ b/packages/flutter/lib/src/cupertino/nav_bar.dart
@@ -910,13 +910,13 @@ class _PersistentNavigationBar extends StatelessWidget {
 @immutable
 class _NavigationBarStaticComponentsKeys {
   _NavigationBarStaticComponentsKeys()
-      : navBarBoxKey = GlobalKey(debugLabel: 'Navigation bar render box'),
-        leadingKey = GlobalKey(debugLabel: 'Leading'),
-        backChevronKey = GlobalKey(debugLabel: 'Back chevron'),
-        backLabelKey = GlobalKey(debugLabel: 'Back label'),
-        middleKey = GlobalKey(debugLabel: 'Middle'),
-        trailingKey = GlobalKey(debugLabel: 'Trailing'),
-        largeTitleKey = GlobalKey(debugLabel: 'Large title');
+    : navBarBoxKey = GlobalKey(debugLabel: 'Navigation bar render box'),
+      leadingKey = GlobalKey(debugLabel: 'Leading'),
+      backChevronKey = GlobalKey(debugLabel: 'Back chevron'),
+      backLabelKey = GlobalKey(debugLabel: 'Back label'),
+      middleKey = GlobalKey(debugLabel: 'Middle'),
+      trailingKey = GlobalKey(debugLabel: 'Trailing'),
+      largeTitleKey = GlobalKey(debugLabel: 'Large title');
 
   final GlobalKey navBarBoxKey;
   final GlobalKey leadingKey;
diff --git a/packages/flutter/lib/src/cupertino/segmented_control.dart b/packages/flutter/lib/src/cupertino/segmented_control.dart
index 17b7321702..720618e893 100644
--- a/packages/flutter/lib/src/cupertino/segmented_control.dart
+++ b/packages/flutter/lib/src/cupertino/segmented_control.dart
@@ -87,14 +87,14 @@ class CupertinoSegmentedControl<T> extends StatefulWidget {
     this.selectedColor,
     this.borderColor,
     this.pressedColor,
-  })  : assert(children != null),
-        assert(children.length >= 2),
-        assert(onValueChanged != null),
-        assert(
-          groupValue == null || children.keys.any((T child) => child == groupValue),
-          'The groupValue must be either null or one of the keys in the children map.',
-        ),
-        super(key: key);
+  }) : assert(children != null),
+       assert(children.length >= 2),
+       assert(onValueChanged != null),
+       assert(
+         groupValue == null || children.keys.any((T child) => child == groupValue),
+         'The groupValue must be either null or one of the keys in the children map.',
+       ),
+       super(key: key);
 
   /// The identifying keys and corresponding widget values in the
   /// segmented control.
@@ -472,12 +472,12 @@ class _RenderSegmentedControl<T> extends RenderBox
     @required TextDirection textDirection,
     @required List<Color> backgroundColors,
     @required Color borderColor,
-  })  : assert(textDirection != null),
-        _textDirection = textDirection,
-        _selectedIndex = selectedIndex,
-        _pressedIndex = pressedIndex,
-        _backgroundColors = backgroundColors,
-        _borderColor = borderColor {
+  }) : assert(textDirection != null),
+       _textDirection = textDirection,
+       _selectedIndex = selectedIndex,
+       _pressedIndex = pressedIndex,
+       _backgroundColors = backgroundColors,
+       _borderColor = borderColor {
     addAll(children);
   }
 
diff --git a/packages/flutter/lib/src/foundation/diagnostics.dart b/packages/flutter/lib/src/foundation/diagnostics.dart
index d533f4c150..8a68ff9080 100644
--- a/packages/flutter/lib/src/foundation/diagnostics.dart
+++ b/packages/flutter/lib/src/foundation/diagnostics.dart
@@ -1753,7 +1753,7 @@ class DiagnosticsProperty<T> extends DiagnosticsNode {
        _valueComputed = false,
        _value = null,
        _computeValue = computeValue,
-        _defaultLevel = level,
+       _defaultLevel = level,
        ifNull = ifNull ?? (missingIfNull ? 'MISSING' : null),
        super(
          name: name,
diff --git a/packages/flutter/lib/src/gestures/long_press.dart b/packages/flutter/lib/src/gestures/long_press.dart
index 61de7a6d75..f9f723989a 100644
--- a/packages/flutter/lib/src/gestures/long_press.dart
+++ b/packages/flutter/lib/src/gestures/long_press.dart
@@ -21,7 +21,7 @@ class LongPressGestureRecognizer extends PrimaryPointerGestureRecognizer {
   ///
   /// Consider assigning the [onLongPress] callback after creating this object.
   LongPressGestureRecognizer({ Object debugOwner })
-      : super(deadline: kLongPressTimeout, debugOwner: debugOwner);
+    : super(deadline: kLongPressTimeout, debugOwner: debugOwner);
 
   bool _longPressAccepted = false;
 
diff --git a/packages/flutter/lib/src/gestures/lsq_solver.dart b/packages/flutter/lib/src/gestures/lsq_solver.dart
index 1a540c2d43..509d7ea697 100644
--- a/packages/flutter/lib/src/gestures/lsq_solver.dart
+++ b/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;
 
@@ -36,8 +41,8 @@ class _Vector {
 // TODO(abarth): Consider using vector_math.
 class _Matrix {
   _Matrix(int rows, int cols)
-  : _columns = cols,
-    _elements = Float64List(rows * cols);
+    : _columns = cols,
+      _elements = Float64List(rows * cols);
 
   final int _columns;
   final List<double> _elements;
diff --git a/packages/flutter/lib/src/gestures/monodrag.dart b/packages/flutter/lib/src/gestures/monodrag.dart
index 8f7522e82b..494655d6fe 100644
--- a/packages/flutter/lib/src/gestures/monodrag.dart
+++ b/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 }) :
-        super(debugOwner: debugOwner);
+  HorizontalDragGestureRecognizer({ Object debugOwner }) : super(debugOwner: debugOwner);
 
   @override
   bool _isFlingGesture(VelocityEstimate estimate) {
diff --git a/packages/flutter/lib/src/gestures/multidrag.dart b/packages/flutter/lib/src/gestures/multidrag.dart
index 1b115f6566..ca028a7b0b 100644
--- a/packages/flutter/lib/src/gestures/multidrag.dart
+++ b/packages/flutter/lib/src/gestures/multidrag.dart
@@ -439,8 +439,8 @@ class VerticalMultiDragGestureRecognizer extends MultiDragGestureRecognizer<_Ver
 
 class _DelayedPointerState extends MultiDragPointerState {
   _DelayedPointerState(Offset initialPosition, Duration delay)
-    : assert(delay != null),
-      super(initialPosition) {
+      : assert(delay != null),
+        super(initialPosition) {
     _timer = Timer(delay, _delayPassed);
   }
 
diff --git a/packages/flutter/lib/src/gestures/velocity_tracker.dart b/packages/flutter/lib/src/gestures/velocity_tracker.dart
index 4f548d408e..ea84344d32 100644
--- a/packages/flutter/lib/src/gestures/velocity_tracker.dart
+++ b/packages/flutter/lib/src/gestures/velocity_tracker.dart
@@ -126,8 +126,8 @@ class VelocityEstimate {
 
 class _PointAtTime {
   const _PointAtTime(this.point, this.time)
-      : assert(point != null),
-        assert(time != null);
+    : assert(point != null),
+      assert(time != null);
 
   final Duration time;
   final Offset point;
diff --git a/packages/flutter/lib/src/material/checkbox.dart b/packages/flutter/lib/src/material/checkbox.dart
index d471735194..849ebd0fbd 100644
--- a/packages/flutter/lib/src/material/checkbox.dart
+++ b/packages/flutter/lib/src/material/checkbox.dart
@@ -220,16 +220,16 @@ class _RenderCheckbox extends RenderToggleable {
     BoxConstraints additionalConstraints,
     ValueChanged<bool> onChanged,
     @required TickerProvider vsync,
-  }): _oldValue = value,
-      super(
-        value: value,
-        tristate: tristate,
-        activeColor: activeColor,
-        inactiveColor: inactiveColor,
-        onChanged: onChanged,
-        additionalConstraints: additionalConstraints,
-        vsync: vsync,
-      );
+  }) : _oldValue = value,
+       super(
+         value: value,
+         tristate: tristate,
+         activeColor: activeColor,
+         inactiveColor: inactiveColor,
+         onChanged: onChanged,
+         additionalConstraints: additionalConstraints,
+         vsync: vsync,
+       );
 
   bool _oldValue;
 
diff --git a/packages/flutter/lib/src/material/chip.dart b/packages/flutter/lib/src/material/chip.dart
index af83b4e2c8..237bd4c5aa 100644
--- a/packages/flutter/lib/src/material/chip.dart
+++ b/packages/flutter/lib/src/material/chip.dart
@@ -476,9 +476,9 @@ class Chip extends StatelessWidget implements ChipAttributes, DeletableChipAttri
     this.backgroundColor,
     this.padding,
     this.materialTapTargetSize,
-  })  : assert(label != null),
-        assert(clipBehavior != null),
-        super(key: key);
+  }) : assert(label != null),
+       assert(clipBehavior != null),
+       super(key: key);
 
   @override
   final Widget avatar;
@@ -613,11 +613,11 @@ class InputChip extends StatelessWidget
     this.padding,
     this.materialTapTargetSize,
     this.avatarBorder = const CircleBorder(),
-  })  : assert(selected != null),
-        assert(isEnabled != null),
-        assert(label != null),
-        assert(clipBehavior != null),
-        super(key: key);
+  }) : assert(selected != null),
+       assert(isEnabled != null),
+       assert(label != null),
+       assert(clipBehavior != null),
+       super(key: key);
 
   @override
   final Widget avatar;
@@ -775,10 +775,10 @@ class ChoiceChip extends StatelessWidget
     this.padding,
     this.materialTapTargetSize,
     this.avatarBorder = const CircleBorder(),
-  })  : assert(selected != null),
-        assert(label != null),
-        assert(clipBehavior != null),
-        super(key: key);
+  }) : assert(selected != null),
+       assert(label != null),
+       assert(clipBehavior != null),
+       super(key: key);
 
   @override
   final Widget avatar;
@@ -956,10 +956,10 @@ class FilterChip extends StatelessWidget
     this.padding,
     this.materialTapTargetSize,
     this.avatarBorder = const CircleBorder(),
-  })  : assert(selected != null),
-        assert(label != null),
-        assert(clipBehavior != null),
-        super(key: key);
+  }) : assert(selected != null),
+       assert(label != null),
+       assert(clipBehavior != null),
+       super(key: key);
 
   @override
   final Widget avatar;
@@ -1087,13 +1087,13 @@ class ActionChip extends StatelessWidget implements ChipAttributes, TappableChip
     this.backgroundColor,
     this.padding,
     this.materialTapTargetSize,
-  })  : assert(label != null),
-        assert(
-          onPressed != null,
-          'Rather than disabling an ActionChip by setting onPressed to null, '
-          'remove it from the interface entirely.',
-        ),
-        super(key: key);
+  }) : assert(label != null),
+       assert(
+         onPressed != null,
+         'Rather than disabling an ActionChip by setting onPressed to null, '
+         'remove it from the interface entirely.',
+       ),
+       super(key: key);
 
   @override
   final Widget avatar;
@@ -1211,12 +1211,12 @@ class RawChip extends StatefulWidget
     this.backgroundColor,
     this.materialTapTargetSize,
     this.avatarBorder = const CircleBorder(),
-  })  : assert(label != null),
-        assert(isEnabled != null),
-        assert(clipBehavior != null),
-        assert(pressElevation != null && pressElevation >= 0.0),
-        deleteIcon = deleteIcon ?? _kDefaultDeleteIcon,
-        super(key: key);
+  }) : assert(label != null),
+       assert(isEnabled != null),
+       assert(clipBehavior != null),
+       assert(pressElevation != null && pressElevation >= 0.0),
+       deleteIcon = deleteIcon ?? _kDefaultDeleteIcon,
+       super(key: key);
 
   @override
   final Widget avatar;
@@ -1649,8 +1649,8 @@ class _ChipRenderWidget extends RenderObjectWidget {
     this.deleteDrawerAnimation,
     this.enableAnimation,
     this.avatarBorder,
-  })  : assert(theme != null),
-        super(key: key);
+  }) : assert(theme != null),
+       super(key: key);
 
   final _ChipRenderTheme theme;
   final bool value;
@@ -1878,10 +1878,10 @@ class _RenderChip extends RenderBox {
     this.deleteDrawerAnimation,
     this.enableAnimation,
     this.avatarBorder,
-  })  : assert(theme != null),
-        assert(textDirection != null),
-        _theme = theme,
-        _textDirection = textDirection {
+  }) : assert(theme != null),
+       assert(textDirection != null),
+       _theme = theme,
+       _textDirection = textDirection {
     checkmarkAnimation.addListener(markNeedsPaint);
     avatarDrawerAnimation.addListener(markNeedsLayout);
     deleteDrawerAnimation.addListener(markNeedsLayout);
diff --git a/packages/flutter/lib/src/material/chip_theme.dart b/packages/flutter/lib/src/material/chip_theme.dart
index 048ec3eb3f..b4d076e7f4 100644
--- a/packages/flutter/lib/src/material/chip_theme.dart
+++ b/packages/flutter/lib/src/material/chip_theme.dart
@@ -46,9 +46,9 @@ class ChipTheme extends InheritedWidget {
     Key key,
     @required this.data,
     @required Widget child,
-  })  : assert(child != null),
-        assert(data != null),
-        super(key: key, child: child);
+  }) : assert(child != null),
+       assert(data != null),
+       super(key: key, child: child);
 
   /// Specifies the color, shape, and text style values for descendant chip
   /// widgets.
@@ -178,16 +178,16 @@ class ChipThemeData extends Diagnosticable {
     @required this.labelStyle,
     @required this.secondaryLabelStyle,
     @required this.brightness,
-  })  : assert(backgroundColor != null),
-        assert(disabledColor != null),
-        assert(selectedColor != null),
-        assert(secondarySelectedColor != null),
-        assert(labelPadding != null),
-        assert(padding != null),
-        assert(shape != null),
-        assert(labelStyle != null),
-        assert(secondaryLabelStyle != null),
-        assert(brightness != null);
+  }) : assert(backgroundColor != null),
+       assert(disabledColor != null),
+       assert(selectedColor != null),
+       assert(secondarySelectedColor != null),
+       assert(labelPadding != null),
+       assert(padding != null),
+       assert(shape != null),
+       assert(labelStyle != null),
+       assert(secondaryLabelStyle != null),
+       assert(brightness != null);
 
   /// Generates a ChipThemeData from a brightness, a primary color, and a text
   /// style.
diff --git a/packages/flutter/lib/src/material/circle_avatar.dart b/packages/flutter/lib/src/material/circle_avatar.dart
index 7461eb1da5..12a60c84e2 100644
--- a/packages/flutter/lib/src/material/circle_avatar.dart
+++ b/packages/flutter/lib/src/material/circle_avatar.dart
@@ -61,8 +61,8 @@ class CircleAvatar extends StatelessWidget {
     this.radius,
     this.minRadius,
     this.maxRadius,
-  })  : assert(radius == null || (minRadius == null && maxRadius == null)),
-        super(key: key);
+  }) : assert(radius == null || (minRadius == null && maxRadius == null)),
+       super(key: key);
 
   /// The widget below this widget in the tree.
   ///
diff --git a/packages/flutter/lib/src/material/flexible_space_bar.dart b/packages/flutter/lib/src/material/flexible_space_bar.dart
index c550f04a0e..8fe7f5dd7d 100644
--- a/packages/flutter/lib/src/material/flexible_space_bar.dart
+++ b/packages/flutter/lib/src/material/flexible_space_bar.dart
@@ -251,8 +251,8 @@ class FlexibleSpaceBarSettings extends InheritedWidget {
     this.maxExtent,
     @required this.currentExtent,
     @required Widget child,
-  }) :  assert(currentExtent != null),
-        super(key: key, child: child);
+  }) : assert(currentExtent != null),
+       super(key: key, child: child);
 
   /// Affects how transparent the text within the toolbar appears.
   final double toolbarOpacity;
diff --git a/packages/flutter/lib/src/material/floating_action_button.dart b/packages/flutter/lib/src/material/floating_action_button.dart
index fe28efe5bf..9f820a9ad9 100644
--- a/packages/flutter/lib/src/material/floating_action_button.dart
+++ b/packages/flutter/lib/src/material/floating_action_button.dart
@@ -82,15 +82,15 @@ class FloatingActionButton extends StatelessWidget {
     this.clipBehavior = Clip.none,
     this.materialTapTargetSize,
     this.isExtended = false,
-  }) :  assert(elevation != null && elevation >= 0.0),
-        assert(highlightElevation != null && highlightElevation >= 0.0),
-        assert(disabledElevation == null || disabledElevation >= 0.0),
-        assert(mini != null),
-        assert(shape != null),
-        assert(isExtended != null),
-        _sizeConstraints = mini ? _kMiniSizeConstraints : _kSizeConstraints,
-        disabledElevation = disabledElevation ?? elevation,
-        super(key: key);
+  }) : assert(elevation != null && elevation >= 0.0),
+       assert(highlightElevation != null && highlightElevation >= 0.0),
+       assert(disabledElevation == null || disabledElevation >= 0.0),
+       assert(mini != null),
+       assert(shape != null),
+       assert(isExtended != null),
+       _sizeConstraints = mini ? _kMiniSizeConstraints : _kSizeConstraints,
+       disabledElevation = disabledElevation ?? elevation,
+       super(key: key);
 
   /// Creates a wider [StadiumBorder]-shaped floating action button with both
   /// an [icon] and a [label].
@@ -115,28 +115,28 @@ class FloatingActionButton extends StatelessWidget {
     this.clipBehavior = Clip.none,
     @required Widget icon,
     @required Widget label,
-  }) :  assert(elevation != null && elevation >= 0.0),
-        assert(highlightElevation != null && highlightElevation >= 0.0),
-        assert(disabledElevation == null || disabledElevation >= 0.0),
-        assert(shape != null),
-        assert(isExtended != null),
-        assert(clipBehavior != null),
-        _sizeConstraints = _kExtendedSizeConstraints,
-        disabledElevation = disabledElevation ?? elevation,
-        mini = false,
-        child = _ChildOverflowBox(
-          child: Row(
-            mainAxisSize: MainAxisSize.min,
-            children: <Widget>[
-              const SizedBox(width: 16.0),
-              icon,
-              const SizedBox(width: 8.0),
-              label,
-              const SizedBox(width: 20.0),
-            ],
-          ),
-        ),
-        super(key: key);
+  }) : assert(elevation != null && elevation >= 0.0),
+       assert(highlightElevation != null && highlightElevation >= 0.0),
+       assert(disabledElevation == null || disabledElevation >= 0.0),
+       assert(shape != null),
+       assert(isExtended != null),
+       assert(clipBehavior != null),
+       _sizeConstraints = _kExtendedSizeConstraints,
+       disabledElevation = disabledElevation ?? elevation,
+       mini = false,
+       child = _ChildOverflowBox(
+         child: Row(
+           mainAxisSize: MainAxisSize.min,
+           children: <Widget>[
+             const SizedBox(width: 16.0),
+             icon,
+             const SizedBox(width: 8.0),
+             label,
+             const SizedBox(width: 20.0),
+           ],
+         ),
+       ),
+       super(key: key);
 
   /// The widget below this widget in the tree.
   ///
diff --git a/packages/flutter/lib/src/material/floating_action_button_location.dart b/packages/flutter/lib/src/material/floating_action_button_location.dart
index 188a6f4f30..af7a97c3c3 100644
--- a/packages/flutter/lib/src/material/floating_action_button_location.dart
+++ b/packages/flutter/lib/src/material/floating_action_button_location.dart
@@ -470,7 +470,7 @@ class _AnimationSwap<T> extends CompoundAnimation<T> {
   ///
   /// Both arguments must be non-null. Either can be an [_AnimationSwap] itself
   /// to combine multiple animations.
-  _AnimationSwap(Animation<T> first, Animation<T> next, this.parent, this.swapThreshold): super(first: first, next: next);
+  _AnimationSwap(Animation<T> first, Animation<T> next, this.parent, this.swapThreshold) : super(first: first, next: next);
 
   final Animation<double> parent;
   final double swapThreshold;
diff --git a/packages/flutter/lib/src/material/material.dart b/packages/flutter/lib/src/material/material.dart
index 02fb410d84..02e6a6c84a 100644
--- a/packages/flutter/lib/src/material/material.dart
+++ b/packages/flutter/lib/src/material/material.dart
@@ -600,7 +600,7 @@ class ShapeBorderTween extends Tween<ShapeBorder> {
   ///
   /// the [begin] and [end] properties may be null; see [ShapeBorder.lerp] for
   /// the null handling semantics.
-  ShapeBorderTween({ShapeBorder begin, ShapeBorder end}): super(begin: begin, end: end);
+  ShapeBorderTween({ShapeBorder begin, ShapeBorder end}) : super(begin: begin, end: end);
 
   /// Returns the value this tween has at the given animation clock value.
   @override
diff --git a/packages/flutter/lib/src/material/radio.dart b/packages/flutter/lib/src/material/radio.dart
index 5658ca12cb..33ca07cba6 100644
--- a/packages/flutter/lib/src/material/radio.dart
+++ b/packages/flutter/lib/src/material/radio.dart
@@ -200,15 +200,15 @@ class _RenderRadio extends RenderToggleable {
     ValueChanged<bool> onChanged,
     BoxConstraints additionalConstraints,
     @required TickerProvider vsync,
-  }): super(
-    value: value,
-    tristate: false,
-    activeColor: activeColor,
-    inactiveColor: inactiveColor,
-    onChanged: onChanged,
-    additionalConstraints: additionalConstraints,
-    vsync: vsync,
-  );
+  }) : super(
+         value: value,
+         tristate: false,
+         activeColor: activeColor,
+         inactiveColor: inactiveColor,
+         onChanged: onChanged,
+         additionalConstraints: additionalConstraints,
+         vsync: vsync,
+       );
 
   @override
   void paint(PaintingContext context, Offset offset) {
diff --git a/packages/flutter/lib/src/material/reorderable_list.dart b/packages/flutter/lib/src/material/reorderable_list.dart
index 17a38ac663..81dc9c3023 100644
--- a/packages/flutter/lib/src/material/reorderable_list.dart
+++ b/packages/flutter/lib/src/material/reorderable_list.dart
@@ -60,13 +60,13 @@ class ReorderableListView extends StatefulWidget {
     this.scrollDirection = Axis.vertical,
     this.padding,
     this.reverse = false,
-  }): assert(scrollDirection != null),
-      assert(onReorder != null),
-      assert(children != null),
-      assert(
-        children.every((Widget w) => w.key != null),
-        'All children of this widget must have a key.',
-      );
+  }) : assert(scrollDirection != null),
+       assert(onReorder != null),
+       assert(children != null),
+       assert(
+         children.every((Widget w) => w.key != null),
+         'All children of this widget must have a key.',
+       );
 
   /// A non-reorderable header widget to show before the list.
   ///
diff --git a/packages/flutter/lib/src/material/slider_theme.dart b/packages/flutter/lib/src/material/slider_theme.dart
index aa22e6a235..efa9788ad4 100644
--- a/packages/flutter/lib/src/material/slider_theme.dart
+++ b/packages/flutter/lib/src/material/slider_theme.dart
@@ -35,9 +35,9 @@ class SliderTheme extends InheritedWidget {
     Key key,
     @required this.data,
     @required Widget child,
-  })  : assert(child != null),
-        assert(data != null),
-        super(key: key, child: child);
+  }) : assert(child != null),
+       assert(data != null),
+       super(key: key, child: child);
 
   /// Specifies the color and shape values for descendant slider widgets.
   final SliderThemeData data;
@@ -197,22 +197,22 @@ class SliderThemeData extends Diagnosticable {
     @required this.valueIndicatorShape,
     @required this.showValueIndicator,
     @required this.valueIndicatorTextStyle,
-  })  : assert(activeTrackColor != null),
-        assert(inactiveTrackColor != null),
-        assert(disabledActiveTrackColor != null),
-        assert(disabledInactiveTrackColor != null),
-        assert(activeTickMarkColor != null),
-        assert(inactiveTickMarkColor != null),
-        assert(disabledActiveTickMarkColor != null),
-        assert(disabledInactiveTickMarkColor != null),
-        assert(thumbColor != null),
-        assert(disabledThumbColor != null),
-        assert(overlayColor != null),
-        assert(valueIndicatorColor != null),
-        assert(thumbShape != null),
-        assert(valueIndicatorShape != null),
-        assert(valueIndicatorTextStyle != null),
-        assert(showValueIndicator != null);
+  }) : assert(activeTrackColor != null),
+       assert(inactiveTrackColor != null),
+       assert(disabledActiveTrackColor != null),
+       assert(disabledInactiveTrackColor != null),
+       assert(activeTickMarkColor != null),
+       assert(inactiveTickMarkColor != null),
+       assert(disabledActiveTickMarkColor != null),
+       assert(disabledInactiveTickMarkColor != null),
+       assert(thumbColor != null),
+       assert(disabledThumbColor != null),
+       assert(overlayColor != null),
+       assert(valueIndicatorColor != null),
+       assert(thumbShape != null),
+       assert(valueIndicatorShape != null),
+       assert(valueIndicatorTextStyle != null),
+       assert(showValueIndicator != null);
 
   /// Generates a SliderThemeData from three main colors.
   ///
diff --git a/packages/flutter/lib/src/material/tab_indicator.dart b/packages/flutter/lib/src/material/tab_indicator.dart
index 51d1ee6de2..d0ca571526 100644
--- a/packages/flutter/lib/src/material/tab_indicator.dart
+++ b/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;
 
diff --git a/packages/flutter/lib/src/material/tabs.dart b/packages/flutter/lib/src/material/tabs.dart
index 7c71b7812a..5c132ee831 100644
--- a/packages/flutter/lib/src/material/tabs.dart
+++ b/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.
   ///
diff --git a/packages/flutter/lib/src/material/time.dart b/packages/flutter/lib/src/material/time.dart
index 6e82b747e8..ca9d1ba0e1 100644
--- a/packages/flutter/lib/src/material/time.dart
+++ b/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.
   ///
diff --git a/packages/flutter/lib/src/material/time_picker.dart b/packages/flutter/lib/src/material/time_picker.dart
index 650bed5019..526dd54ea8 100644
--- a/packages/flutter/lib/src/material/time_picker.dart
+++ b/packages/flutter/lib/src/material/time_picker.dart
@@ -112,8 +112,8 @@ class _TimePickerHeaderFragment {
     @required this.widget,
     this.startMargin = 0.0,
   }) : assert(layoutId != null),
-        assert(widget != null),
-        assert(startMargin != null);
+       assert(widget != null),
+       assert(startMargin != null);
 
   /// Identifier used by the custom layout to refer to the widget.
   final _TimePickerHeaderId layoutId;
@@ -140,9 +140,9 @@ class _TimePickerHeaderPiece {
   /// All arguments must be non-null. If the piece does not contain a pivot
   /// fragment, use the value -1 as a convention.
   const _TimePickerHeaderPiece(this.pivotIndex, this.fragments, { this.bottomMargin = 0.0 })
-      : assert(pivotIndex != null),
-        assert(fragments != null),
-        assert(bottomMargin != null);
+    : assert(pivotIndex != null),
+      assert(fragments != null),
+      assert(bottomMargin != null);
 
   /// Index into the [fragments] list, pointing at the fragment that's centered
   /// horizontally.
@@ -175,8 +175,8 @@ class _TimePickerHeaderPiece {
 /// to the left or right of it.
 class _TimePickerHeaderFormat {
   const _TimePickerHeaderFormat(this.centrepieceIndex, this.pieces)
-      : assert(centrepieceIndex != null),
-        assert(pieces != null);
+    : assert(centrepieceIndex != null),
+      assert(pieces != null);
 
   /// Index into the [pieces] list pointing at the piece that contains the
   /// pivot fragment.
diff --git a/packages/flutter/lib/src/painting/colors.dart b/packages/flutter/lib/src/painting/colors.dart
index e38f1adeee..4eba576a9f 100644
--- a/packages/flutter/lib/src/painting/colors.dart
+++ b/packages/flutter/lib/src/painting/colors.dart
@@ -89,18 +89,18 @@ class HSVColor {
   /// All the arguments must not be null and be in their respective ranges. See
   /// the fields for each parameter for a description of their ranges.
   const HSVColor.fromAHSV(this.alpha, this.hue, this.saturation, this.value)
-      : assert(alpha != null),
-        assert(hue != null),
-        assert(saturation != null),
-        assert(value != null),
-        assert(alpha >= 0.0),
-        assert(alpha <= 1.0),
-        assert(hue >= 0.0),
-        assert(hue <= 360.0),
-        assert(saturation >= 0.0),
-        assert(saturation <= 1.0),
-        assert(value >= 0.0),
-        assert(value <= 1.0);
+    : assert(alpha != null),
+      assert(hue != null),
+      assert(saturation != null),
+      assert(value != null),
+      assert(alpha >= 0.0),
+      assert(alpha <= 1.0),
+      assert(hue >= 0.0),
+      assert(hue <= 360.0),
+      assert(saturation >= 0.0),
+      assert(saturation <= 1.0),
+      assert(value >= 0.0),
+      assert(value <= 1.0);
 
   /// Creates an [HSVColor] from an RGB [Color].
   ///
diff --git a/packages/flutter/lib/src/painting/edge_insets.dart b/packages/flutter/lib/src/painting/edge_insets.dart
index a485334c2e..9ff3269e48 100644
--- a/packages/flutter/lib/src/painting/edge_insets.dart
+++ b/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,
-                             double horizontal = 0.0 })
-    : left = horizontal, top = vertical, right = horizontal, bottom = vertical;
+  const EdgeInsets.symmetric({
+    double vertical = 0.0,
+    double horizontal = 0.0,
+  }) : left = horizontal,
+       top = vertical,
+       right = horizontal,
+       bottom = vertical;
 
   /// Creates insets that match the given window padding.
   ///
diff --git a/packages/flutter/lib/src/painting/flutter_logo.dart b/packages/flutter/lib/src/painting/flutter_logo.dart
index 44a67b66b4..2b7bddd2c8 100644
--- a/packages/flutter/lib/src/painting/flutter_logo.dart
+++ b/packages/flutter/lib/src/painting/flutter_logo.dart
@@ -246,9 +246,9 @@ class FlutterLogoDecoration extends Decoration {
 /// An object that paints a [BoxDecoration] into a canvas.
 class _FlutterLogoPainter extends BoxPainter {
   _FlutterLogoPainter(this._config)
-    : assert(_config != null),
-      assert(_config.debugAssertIsValid()),
-      super(null) {
+      : assert(_config != null),
+        assert(_config.debugAssertIsValid()),
+        super(null) {
     _prepareText();
   }
 
diff --git a/packages/flutter/lib/src/painting/image_provider.dart b/packages/flutter/lib/src/painting/image_provider.dart
index c8564b6fb7..161517d713 100644
--- a/packages/flutter/lib/src/painting/image_provider.dart
+++ b/packages/flutter/lib/src/painting/image_provider.dart
@@ -452,8 +452,8 @@ class NetworkImage extends ImageProvider<NetworkImage> {
   ///
   /// The arguments must not be null.
   const NetworkImage(this.url, { this.scale = 1.0 , this.headers })
-      : assert(url != null),
-        assert(scale != null);
+    : assert(url != null),
+      assert(scale != null);
 
   /// The URL from which the image will be fetched.
   final String url;
@@ -529,8 +529,8 @@ class FileImage extends ImageProvider<FileImage> {
   ///
   /// The arguments must not be null.
   const FileImage(this.file, { this.scale = 1.0 })
-      : assert(file != null),
-        assert(scale != null);
+    : assert(file != null),
+      assert(scale != null);
 
   /// The file to decode into an image.
   final File file;
@@ -597,8 +597,8 @@ class MemoryImage extends ImageProvider<MemoryImage> {
   ///
   /// The arguments must not be null.
   const MemoryImage(this.bytes, { this.scale = 1.0 })
-      : assert(bytes != null),
-        assert(scale != null);
+    : assert(bytes != null),
+      assert(scale != null);
 
   /// The bytes to decode into an image.
   final Uint8List bytes;
diff --git a/packages/flutter/lib/src/painting/image_stream.dart b/packages/flutter/lib/src/painting/image_stream.dart
index b529eb730d..2a20a328f5 100644
--- a/packages/flutter/lib/src/painting/image_stream.dart
+++ b/packages/flutter/lib/src/painting/image_stream.dart
@@ -19,8 +19,8 @@ class ImageInfo {
   ///
   /// Both the image and the scale must not be null.
   const ImageInfo({ @required this.image, this.scale = 1.0 })
-      : assert(image != null),
-        assert(scale != null);
+    : assert(image != null),
+      assert(scale != null);
 
   /// The raw image pixels.
   ///
@@ -371,7 +371,7 @@ class OneFrameImageStreamCompleter extends ImageStreamCompleter {
   /// message is only dumped to the console in debug mode (see [new
   /// FlutterErrorDetails]).
   OneFrameImageStreamCompleter(Future<ImageInfo> image, { InformationCollector informationCollector })
-    : assert(image != null) {
+      : assert(image != null) {
     image.then<void>(setImage, onError: (dynamic error, StackTrace stack) {
       reportError(
         context: 'resolving a single-frame image stream',
diff --git a/packages/flutter/lib/src/physics/spring_simulation.dart b/packages/flutter/lib/src/physics/spring_simulation.dart
index d33154c048..f6622813dd 100644
--- a/packages/flutter/lib/src/physics/spring_simulation.dart
+++ b/packages/flutter/lib/src/physics/spring_simulation.dart
@@ -94,8 +94,8 @@ class SpringSimulation extends Simulation {
     double velocity, {
     Tolerance tolerance = Tolerance.defaultTolerance,
   }) : _endPosition = end,
-      _solution = _SpringSolution(spring, start - end, velocity),
-      super(tolerance: tolerance);
+       _solution = _SpringSolution(spring, start - end, velocity),
+       super(tolerance: tolerance);
 
   final double _endPosition;
   final _SpringSolution _solution;
diff --git a/packages/flutter/lib/src/rendering/box.dart b/packages/flutter/lib/src/rendering/box.dart
index 89f1b5c826..947ab1f050 100644
--- a/packages/flutter/lib/src/rendering/box.dart
+++ b/packages/flutter/lib/src/rendering/box.dart
@@ -109,10 +109,10 @@ class BoxConstraints extends Constraints {
   const BoxConstraints.tightFor({
     double width,
     double height
-  }): minWidth = width != null ? width : 0.0,
-      maxWidth = width != null ? width : double.infinity,
-      minHeight = height != null ? height : 0.0,
-      maxHeight = height != null ? height : double.infinity;
+  }) : minWidth = width != null ? width : 0.0,
+       maxWidth = width != null ? width : double.infinity,
+       minHeight = height != null ? height : 0.0,
+       maxHeight = height != null ? height : double.infinity;
 
   /// Creates box constraints that require the given width or height, except if
   /// they are infinite.
@@ -124,10 +124,10 @@ class BoxConstraints extends Constraints {
   const BoxConstraints.tightForFinite({
     double width = double.infinity,
     double height = double.infinity
-  }): minWidth = width != double.infinity ? width : 0.0,
-      maxWidth = width != double.infinity ? width : double.infinity,
-      minHeight = height != double.infinity ? height : 0.0,
-      maxHeight = height != double.infinity ? height : double.infinity;
+  }) : minWidth = width != double.infinity ? width : 0.0,
+       maxWidth = width != double.infinity ? width : double.infinity,
+       minHeight = height != double.infinity ? height : 0.0,
+       maxHeight = height != double.infinity ? height : double.infinity;
 
   /// Creates box constraints that forbid sizes larger than the given size.
   BoxConstraints.loose(Size size)
@@ -143,10 +143,10 @@ class BoxConstraints extends Constraints {
   const BoxConstraints.expand({
     double width,
     double height
-  }): minWidth = width != null ? width : double.infinity,
-      maxWidth = width != null ? width : double.infinity,
-      minHeight = height != null ? height : double.infinity,
-      maxHeight = height != null ? height : double.infinity;
+  }) : minWidth = width != null ? width : double.infinity,
+       maxWidth = width != null ? width : double.infinity,
+       minHeight = height != null ? height : double.infinity,
+       maxHeight = height != null ? height : double.infinity;
 
   /// The minimum width that satisfies the constraints.
   final double minWidth;
@@ -615,8 +615,8 @@ class BoxHitTestEntry extends HitTestEntry {
   ///
   /// The [localPosition] argument must not be null.
   const BoxHitTestEntry(RenderBox target, this.localPosition)
-      : assert(localPosition != null),
-        super(target);
+    : assert(localPosition != null),
+      super(target);
 
   @override
   RenderBox get target => super.target;
diff --git a/packages/flutter/lib/src/rendering/editable.dart b/packages/flutter/lib/src/rendering/editable.dart
index 054e763985..dbc5f89919 100644
--- a/packages/flutter/lib/src/rendering/editable.dart
+++ b/packages/flutter/lib/src/rendering/editable.dart
@@ -69,7 +69,7 @@ class TextSelectionPoint {
   ///
   /// The [point] argument must not be null.
   const TextSelectionPoint(this.point, this.direction)
-      : assert(point != null);
+    : assert(point != null);
 
   /// Coordinates of the lower left or lower right corner of the selection,
   /// relative to the top left of the [RenderEditable] object.
diff --git a/packages/flutter/lib/src/rendering/layer.dart b/packages/flutter/lib/src/rendering/layer.dart
index f3db290c28..b79933e472 100644
--- a/packages/flutter/lib/src/rendering/layer.dart
+++ b/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 }) :
-        _clipRect = clipRect, _clipBehavior = clipBehavior,
-        assert(clipBehavior != null), assert(clipBehavior != Clip.none);
+  ClipRectLayer({
+    @required Rect clipRect,
+    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 }) :
-        _clipRRect = clipRRect, _clipBehavior = clipBehavior,
-        assert(clipBehavior != null), assert(clipBehavior != Clip.none);
+  ClipRRectLayer({
+    @required RRect clipRRect,
+    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 }) :
-        _clipPath = clipPath, _clipBehavior = clipBehavior,
-        assert(clipBehavior != null), assert(clipBehavior != Clip.none);
+  ClipPathLayer({
+    @required Path clipPath,
+    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 })
-      : _alpha = alpha, _offset = offset;
+  OpacityLayer({
+    @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 })
-      : _shader = shader, _maskRect = maskRect, _blendMode = blendMode;
+  ShaderMaskLayer({
+    @required Shader shader,
+    @required Rect maskRect,
+    @required BlendMode blendMode,
+  }) : _shader = shader,
+       _maskRect = maskRect,
+       _blendMode = blendMode;
 
   /// The shader to apply to the children.
   ///
diff --git a/packages/flutter/lib/src/rendering/object.dart b/packages/flutter/lib/src/rendering/object.dart
index 4c2928c165..a96ae36d18 100644
--- a/packages/flutter/lib/src/rendering/object.dart
+++ b/packages/flutter/lib/src/rendering/object.dart
@@ -612,7 +612,7 @@ typedef LayoutCallback<T extends Constraints> = void Function(T constraints);
 /// You can obtain the [PipelineOwner] using the [RenderObject.owner] property.
 class SemanticsHandle {
   SemanticsHandle._(this._owner, this.listener)
-    : assert(_owner != null) {
+      : assert(_owner != null) {
     if (listener != null)
       _owner.semanticsOwner.addListener(listener);
   }
@@ -3122,7 +3122,7 @@ class FlutterErrorDetailsForRendering extends FlutterErrorDetails {
 ///    information of multiple [_InterestingSemanticsFragment] to a parent.
 abstract class _SemanticsFragment {
   _SemanticsFragment({@required this.dropsSemanticsOfPreviousSiblings })
-      : assert (dropsSemanticsOfPreviousSiblings != null);
+    : assert (dropsSemanticsOfPreviousSiblings != null);
 
   /// Incorporate the fragments of children into this fragment.
   void addAll(Iterable<_InterestingSemanticsFragment> fragments);
@@ -3160,7 +3160,7 @@ abstract class _SemanticsFragment {
 class _ContainerSemanticsFragment extends _SemanticsFragment {
 
   _ContainerSemanticsFragment({ @required bool dropsSemanticsOfPreviousSiblings })
-      : super(dropsSemanticsOfPreviousSiblings: dropsSemanticsOfPreviousSiblings);
+    : super(dropsSemanticsOfPreviousSiblings: dropsSemanticsOfPreviousSiblings);
 
   @override
   void addAll(Iterable<_InterestingSemanticsFragment> fragments) {
diff --git a/packages/flutter/lib/src/rendering/proxy_box.dart b/packages/flutter/lib/src/rendering/proxy_box.dart
index d081d42e8e..516d32b6c6 100644
--- a/packages/flutter/lib/src/rendering/proxy_box.dart
+++ b/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);
   }
 
@@ -4485,8 +4498,8 @@ class RenderIndexedSemantics extends RenderProxyBox {
     RenderBox child,
     @required int index,
   }) : assert(index != null),
-        _index = index,
-        super(child);
+       _index = index,
+       super(child);
 
   /// The index used to annotated child semantics.
   int get index => _index;
diff --git a/packages/flutter/lib/src/rendering/sliver_fixed_extent_list.dart b/packages/flutter/lib/src/rendering/sliver_fixed_extent_list.dart
index 3627302dfb..48a71a82a9 100644
--- a/packages/flutter/lib/src/rendering/sliver_fixed_extent_list.dart
+++ b/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;
diff --git a/packages/flutter/lib/src/rendering/sliver_persistent_header.dart b/packages/flutter/lib/src/rendering/sliver_persistent_header.dart
index dbffe0f25c..a00a684cb4 100644
--- a/packages/flutter/lib/src/rendering/sliver_persistent_header.dart
+++ b/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;
diff --git a/packages/flutter/lib/src/rendering/stack.dart b/packages/flutter/lib/src/rendering/stack.dart
index c039eee8ad..360d32ed2a 100644
--- a/packages/flutter/lib/src/rendering/stack.dart
+++ b/packages/flutter/lib/src/rendering/stack.dart
@@ -630,11 +630,12 @@ class RenderIndexedStack extends RenderStack {
     AlignmentGeometry alignment = AlignmentDirectional.topStart,
     TextDirection textDirection,
     int index = 0,
-  }) : _index = index, super(
-    children: children,
-    alignment: alignment,
-    textDirection: textDirection,
-  );
+  }) : _index = index,
+       super(
+         children: children,
+         alignment: alignment,
+         textDirection: textDirection,
+       );
 
   @override
   void visitChildrenForSemantics(RenderObjectVisitor visitor) {
diff --git a/packages/flutter/lib/src/rendering/texture.dart b/packages/flutter/lib/src/rendering/texture.dart
index bf9d1c3b3e..32f594e8f6 100644
--- a/packages/flutter/lib/src/rendering/texture.dart
+++ b/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;
diff --git a/packages/flutter/lib/src/rendering/viewport.dart b/packages/flutter/lib/src/rendering/viewport.dart
index 2fc43a44dd..69c06a2c4f 100644
--- a/packages/flutter/lib/src/rendering/viewport.dart
+++ b/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.
   ///
diff --git a/packages/flutter/lib/src/semantics/semantics_event.dart b/packages/flutter/lib/src/semantics/semantics_event.dart
index dddc52d7fa..8dd69e3f7d 100644
--- a/packages/flutter/lib/src/semantics/semantics_event.dart
+++ b/packages/flutter/lib/src/semantics/semantics_event.dart
@@ -65,10 +65,10 @@ abstract class SemanticsEvent {
 class AnnounceSemanticsEvent extends SemanticsEvent {
 
   /// Constructs an event that triggers an announcement by the platform.
-  const AnnounceSemanticsEvent(this.message, this.textDirection) :
-    assert(message != null),
-    assert(textDirection != null),
-    super('announce');
+  const AnnounceSemanticsEvent(this.message, this.textDirection)
+    : assert(message != null),
+      assert(textDirection != null),
+      super('announce');
 
   /// The message to announce.
   ///
diff --git a/packages/flutter/lib/src/services/raw_keyboard_android.dart b/packages/flutter/lib/src/services/raw_keyboard_android.dart
index fbcf168e1c..cc3cb57653 100644
--- a/packages/flutter/lib/src/services/raw_keyboard_android.dart
+++ b/packages/flutter/lib/src/services/raw_keyboard_android.dart
@@ -23,11 +23,11 @@ class RawKeyEventDataAndroid extends RawKeyEventData {
     this.keyCode = 0,
     this.scanCode = 0,
     this.metaState = 0,
-  })  : assert(flags != null),
-        assert(codePoint != null),
-        assert(keyCode != null),
-        assert(scanCode != null),
-        assert(metaState != null);
+  }) : assert(flags != null),
+       assert(codePoint != null),
+       assert(keyCode != null),
+       assert(scanCode != null),
+       assert(metaState != null);
 
   /// The current set of additional flags for this event.
   ///
diff --git a/packages/flutter/lib/src/services/raw_keyboard_fuschia.dart b/packages/flutter/lib/src/services/raw_keyboard_fuschia.dart
index 52d2638f5a..e62dab9890 100644
--- a/packages/flutter/lib/src/services/raw_keyboard_fuschia.dart
+++ b/packages/flutter/lib/src/services/raw_keyboard_fuschia.dart
@@ -20,9 +20,9 @@ class RawKeyEventDataFuchsia extends RawKeyEventData {
     this.hidUsage = 0,
     this.codePoint = 0,
     this.modifiers = 0,
-  })  : assert(hidUsage != null),
-        assert(codePoint != null),
-        assert(modifiers != null);
+  }) : assert(hidUsage != null),
+       assert(codePoint != null),
+       assert(modifiers != null);
 
   /// The USB HID usage.
   ///
diff --git a/packages/flutter/lib/src/services/text_editing.dart b/packages/flutter/lib/src/services/text_editing.dart
index 3ca883a6d9..a1798be727 100644
--- a/packages/flutter/lib/src/services/text_editing.dart
+++ b/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.
   ///
diff --git a/packages/flutter/lib/src/services/text_formatter.dart b/packages/flutter/lib/src/services/text_formatter.dart
index f64f6d583e..cb9e4e1a74 100644
--- a/packages/flutter/lib/src/services/text_formatter.dart
+++ b/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) :
-    assert(formatFunction != null);
+  _SimpleTextInputFormatter(this.formatFunction)
+    : 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) :
-    assert(whitelistedPattern != null);
+  WhitelistingTextInputFormatter(this.whitelistedPattern)
+    : assert(whitelistedPattern != null);
 
   /// A [Pattern] to extract all instances of allowed characters.
   ///
diff --git a/packages/flutter/lib/src/services/text_input.dart b/packages/flutter/lib/src/services/text_input.dart
index 20b36d2ddd..b5917938cb 100644
--- a/packages/flutter/lib/src/services/text_input.dart
+++ b/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.
   ///
diff --git a/packages/flutter/lib/src/widgets/animated_list.dart b/packages/flutter/lib/src/widgets/animated_list.dart
index 037f358314..2d55174bc7 100644
--- a/packages/flutter/lib/src/widgets/animated_list.dart
+++ b/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;
diff --git a/packages/flutter/lib/src/widgets/animated_switcher.dart b/packages/flutter/lib/src/widgets/animated_switcher.dart
index 6cf4ad62af..45c1fbe47c 100644
--- a/packages/flutter/lib/src/widgets/animated_switcher.dart
+++ b/packages/flutter/lib/src/widgets/animated_switcher.dart
@@ -22,9 +22,9 @@ class _ChildEntry {
     @required this.animation,
     @required this.transition,
     @required this.widgetChild,
-  })  : assert(animation != null),
-        assert(transition != null),
-        assert(controller != null);
+  }) : assert(animation != null),
+       assert(transition != null),
+       assert(controller != null);
 
   // The animation controller for the child's transition.
   final AnimationController controller;
@@ -156,12 +156,12 @@ class AnimatedSwitcher extends StatefulWidget {
     this.switchOutCurve = Curves.linear,
     this.transitionBuilder = AnimatedSwitcher.defaultTransitionBuilder,
     this.layoutBuilder = AnimatedSwitcher.defaultLayoutBuilder,
-  })  : assert(duration != null),
-        assert(switchInCurve != null),
-        assert(switchOutCurve != null),
-        assert(transitionBuilder != null),
-        assert(layoutBuilder != null),
-        super(key: key);
+  }) : assert(duration != null),
+       assert(switchInCurve != null),
+       assert(switchOutCurve != null),
+       assert(transitionBuilder != null),
+       assert(layoutBuilder != null),
+       super(key: key);
 
   /// The current child widget to display. If there was a previous child, then
   /// that child will be faded out using the [switchOutCurve], while the new
diff --git a/packages/flutter/lib/src/widgets/async.dart b/packages/flutter/lib/src/widgets/async.dart
index 703e797b2a..1e025ec67b 100644
--- a/packages/flutter/lib/src/widgets/async.dart
+++ b/packages/flutter/lib/src/widgets/async.dart
@@ -196,8 +196,8 @@ class AsyncSnapshot<T> {
   /// Creates an [AsyncSnapshot] with the specified [connectionState],
   /// and optionally either [data] or [error] (but not both).
   const AsyncSnapshot._(this.connectionState, this.data, this.error)
-      : assert(connectionState != null),
-        assert(!(data != null && error != null));
+    : assert(connectionState != null),
+      assert(!(data != null && error != null));
 
   /// Creates an [AsyncSnapshot] in [ConnectionState.none] with null data and error.
   const AsyncSnapshot.nothing() : this._(ConnectionState.none, null, null);
diff --git a/packages/flutter/lib/src/widgets/basic.dart b/packages/flutter/lib/src/widgets/basic.dart
index 0fbe2fb019..f938f69069 100644
--- a/packages/flutter/lib/src/widgets/basic.dart
+++ b/packages/flutter/lib/src/widgets/basic.dart
@@ -5836,7 +5836,7 @@ class ExcludeSemantics extends SingleChildRenderObjectWidget {
     this.excluding = true,
     Widget child,
   }) : assert(excluding != null),
-        super(key: key, child: child);
+       super(key: key, child: child);
 
   /// Whether this widget is excluded in the semantics tree.
   final bool excluding;
diff --git a/packages/flutter/lib/src/widgets/framework.dart b/packages/flutter/lib/src/widgets/framework.dart
index 8d6d57504e..07ab8058c1 100644
--- a/packages/flutter/lib/src/widgets/framework.dart
+++ b/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(
@@ -4780,7 +4782,7 @@ abstract class RenderObjectElement extends Element {
 /// elements inherit their owner from their parent.
 abstract class RootRenderObjectElement extends RenderObjectElement {
   /// Initializes fields for subclasses.
-  RootRenderObjectElement(RenderObjectWidget widget): super(widget);
+  RootRenderObjectElement(RenderObjectWidget widget) : super(widget);
 
   /// Set the owner of the element. The owner will be propagated to all the
   /// descendants of this element.
@@ -4808,7 +4810,7 @@ abstract class RootRenderObjectElement extends RenderObjectElement {
 /// An [Element] that uses a [LeafRenderObjectWidget] as its configuration.
 class LeafRenderObjectElement extends RenderObjectElement {
   /// Creates an element that uses the given widget as its configuration.
-  LeafRenderObjectElement(LeafRenderObjectWidget widget): super(widget);
+  LeafRenderObjectElement(LeafRenderObjectWidget widget) : super(widget);
 
   @override
   void forgetChild(Element child) {
diff --git a/packages/flutter/lib/src/widgets/gesture_detector.dart b/packages/flutter/lib/src/widgets/gesture_detector.dart
index be01b3f89d..1c50ee1c4b 100644
--- a/packages/flutter/lib/src/widgets/gesture_detector.dart
+++ b/packages/flutter/lib/src/widgets/gesture_detector.dart
@@ -83,9 +83,9 @@ 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) :
-    assert(_constructor != null),
-    assert(_initializer != null);
+  const GestureRecognizerFactoryWithHandlers(this._constructor, this._initializer)
+    : assert(_constructor != null),
+      assert(_initializer != null);
 
   final GestureRecognizerFactoryConstructor<T> _constructor;
 
diff --git a/packages/flutter/lib/src/widgets/icon_theme_data.dart b/packages/flutter/lib/src/widgets/icon_theme_data.dart
index e5e462eaae..61247ec777 100644
--- a/packages/flutter/lib/src/widgets/icon_theme_data.dart
+++ b/packages/flutter/lib/src/widgets/icon_theme_data.dart
@@ -26,9 +26,9 @@ class IconThemeData extends Diagnosticable {
   ///
   /// The [color] is black, the [opacity] is 1.0, and the [size] is 24.0.
   const IconThemeData.fallback()
-      : color = const Color(0xFF000000),
-        _opacity = 1.0,
-        size = 24.0;
+    : color = const Color(0xFF000000),
+      _opacity = 1.0,
+      size = 24.0;
 
   /// Creates a copy of this icon theme but with the given fields replaced with
   /// the new values.
diff --git a/packages/flutter/lib/src/widgets/implicit_animations.dart b/packages/flutter/lib/src/widgets/implicit_animations.dart
index 37ea40f6f1..4c0357bd98 100644
--- a/packages/flutter/lib/src/widgets/implicit_animations.dart
+++ b/packages/flutter/lib/src/widgets/implicit_animations.dart
@@ -769,7 +769,7 @@ class AnimatedPositioned extends ImplicitlyAnimatedWidget {
     @required Duration duration,
   }) : assert(left == null || right == null || width == null),
        assert(top == null || bottom == null || height == null),
-      super(key: key, curve: curve, duration: duration);
+       super(key: key, curve: curve, duration: duration);
 
   /// Creates a widget that animates the rectangle it occupies implicitly.
   ///
@@ -920,7 +920,7 @@ class AnimatedPositionedDirectional extends ImplicitlyAnimatedWidget {
     @required Duration duration,
   }) : assert(start == null || end == null || width == null),
        assert(top == null || bottom == null || height == null),
-      super(key: key, curve: curve, duration: duration);
+       super(key: key, curve: curve, duration: duration);
 
   /// The widget below this widget in the tree.
   ///
diff --git a/packages/flutter/lib/src/widgets/nested_scroll_view.dart b/packages/flutter/lib/src/widgets/nested_scroll_view.dart
index 570e1039b5..839cbe4b8e 100644
--- a/packages/flutter/lib/src/widgets/nested_scroll_view.dart
+++ b/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;
diff --git a/packages/flutter/lib/src/widgets/platform_view.dart b/packages/flutter/lib/src/widgets/platform_view.dart
index d698a6fa97..a946533422 100644
--- a/packages/flutter/lib/src/widgets/platform_view.dart
+++ b/packages/flutter/lib/src/widgets/platform_view.dart
@@ -212,9 +212,9 @@ class UiKitView extends StatefulWidget {
     this.creationParamsCodec,
     this.gestureRecognizers,
   }) : assert(viewType != null),
-        assert(hitTestBehavior != null),
-        assert(creationParams == null || creationParamsCodec != null),
-        super(key: key);
+       assert(hitTestBehavior != null),
+       assert(creationParams == null || creationParamsCodec != null),
+       super(key: key);
 
   // TODO(amirh): reference the iOS API doc once avaliable.
   /// The unique identifier for iOS view type to be embedded by this widget.
diff --git a/packages/flutter/lib/src/widgets/routes.dart b/packages/flutter/lib/src/widgets/routes.dart
index 067542cfc5..8479791cf9 100644
--- a/packages/flutter/lib/src/widgets/routes.dart
+++ b/packages/flutter/lib/src/widgets/routes.dart
@@ -1450,14 +1450,14 @@ class _DialogRoute<T> extends PopupRoute<T> {
     Duration transitionDuration = const Duration(milliseconds: 200),
     RouteTransitionsBuilder transitionBuilder,
     RouteSettings settings,
-  })  : assert(barrierDismissible != null),
-        _pageBuilder = pageBuilder,
-        _barrierDismissible = barrierDismissible,
-        _barrierLabel = barrierLabel,
-        _barrierColor = barrierColor,
-        _transitionDuration = transitionDuration,
-        _transitionBuilder = transitionBuilder,
-        super(settings: settings);
+  }) : assert(barrierDismissible != null),
+       _pageBuilder = pageBuilder,
+       _barrierDismissible = barrierDismissible,
+       _barrierLabel = barrierLabel,
+       _barrierColor = barrierColor,
+       _transitionDuration = transitionDuration,
+       _transitionBuilder = transitionBuilder,
+       super(settings: settings);
 
   final RoutePageBuilder _pageBuilder;
 
diff --git a/packages/flutter/lib/src/widgets/scroll_activity.dart b/packages/flutter/lib/src/widgets/scroll_activity.dart
index eb5630290d..c60a5e000a 100644
--- a/packages/flutter/lib/src/widgets/scroll_activity.dart
+++ b/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;
 
diff --git a/packages/flutter/lib/src/widgets/scroll_view.dart b/packages/flutter/lib/src/widgets/scroll_view.dart
index 3f485005d6..7424562f7d 100644
--- a/packages/flutter/lib/src/widgets/scroll_view.dart
+++ b/packages/flutter/lib/src/widgets/scroll_view.dart
@@ -756,19 +756,20 @@ class ListView extends BoxScrollView {
          addAutomaticKeepAlives: addAutomaticKeepAlives,
          addRepaintBoundaries: addRepaintBoundaries,
          addSemanticIndexes: addSemanticIndexes,
-       ), super(
-    key: key,
-    scrollDirection: scrollDirection,
-    reverse: reverse,
-    controller: controller,
-    primary: primary,
-    physics: physics,
-    shrinkWrap: shrinkWrap,
-    padding: padding,
-    cacheExtent: cacheExtent,
-    semanticChildCount: semanticChildCount ?? children.length,
-    dragStartBehavior: dragStartBehavior,
-  );
+       ),
+       super(
+         key: key,
+         scrollDirection: scrollDirection,
+         reverse: reverse,
+         controller: controller,
+         primary: primary,
+         physics: physics,
+         shrinkWrap: shrinkWrap,
+         padding: padding,
+         cacheExtent: cacheExtent,
+         semanticChildCount: semanticChildCount ?? children.length,
+         dragStartBehavior: dragStartBehavior,
+       );
 
   /// Creates a scrollable, linear array of widgets that are created on demand.
   ///
@@ -820,19 +821,20 @@ class ListView extends BoxScrollView {
          addAutomaticKeepAlives: addAutomaticKeepAlives,
          addRepaintBoundaries: addRepaintBoundaries,
          addSemanticIndexes: addSemanticIndexes,
-       ), super(
-    key: key,
-    scrollDirection: scrollDirection,
-    reverse: reverse,
-    controller: controller,
-    primary: primary,
-    physics: physics,
-    shrinkWrap: shrinkWrap,
-    padding: padding,
-    cacheExtent: cacheExtent,
-    semanticChildCount: semanticChildCount ?? itemCount,
-    dragStartBehavior: dragStartBehavior,
-  );
+       ),
+       super(
+         key: key,
+         scrollDirection: scrollDirection,
+         reverse: reverse,
+         controller: controller,
+         primary: primary,
+         physics: physics,
+         shrinkWrap: shrinkWrap,
+         padding: padding,
+         cacheExtent: cacheExtent,
+         semanticChildCount: semanticChildCount ?? itemCount,
+         dragStartBehavior: dragStartBehavior,
+       );
 
   /// Creates a fixed-length scrollable linear array of list "items" separated
   /// by list item "separators".
@@ -925,18 +927,19 @@ class ListView extends BoxScrollView {
          semanticIndexCallback: (Widget _, int index) {
            return index.isEven ? index ~/ 2 : null;
          }
-       ), super(
-    key: key,
-    scrollDirection: scrollDirection,
-    reverse: reverse,
-    controller: controller,
-    primary: primary,
-    physics: physics,
-    shrinkWrap: shrinkWrap,
-    padding: padding,
-    cacheExtent: cacheExtent,
-    semanticChildCount: _computeSemanticChildCount(itemCount),
-  );
+       ),
+       super(
+         key: key,
+         scrollDirection: scrollDirection,
+         reverse: reverse,
+         controller: controller,
+         primary: primary,
+         physics: physics,
+         shrinkWrap: shrinkWrap,
+         padding: padding,
+         cacheExtent: cacheExtent,
+         semanticChildCount: _computeSemanticChildCount(itemCount),
+       );
 
   /// Creates a scrollable, linear array of widgets with a custom child model.
   ///
@@ -1327,19 +1330,20 @@ class GridView extends BoxScrollView {
          addAutomaticKeepAlives: addAutomaticKeepAlives,
          addRepaintBoundaries: addRepaintBoundaries,
          addSemanticIndexes: addSemanticIndexes,
-       ), super(
-    key: key,
-    scrollDirection: scrollDirection,
-    reverse: reverse,
-    controller: controller,
-    primary: primary,
-    physics: physics,
-    shrinkWrap: shrinkWrap,
-    padding: padding,
-    cacheExtent: cacheExtent,
-    semanticChildCount: semanticChildCount ?? children.length,
-    dragStartBehavior: dragStartBehavior,
-  );
+       ),
+       super(
+         key: key,
+         scrollDirection: scrollDirection,
+         reverse: reverse,
+         controller: controller,
+         primary: primary,
+         physics: physics,
+         shrinkWrap: shrinkWrap,
+         padding: padding,
+         cacheExtent: cacheExtent,
+         semanticChildCount: semanticChildCount ?? children.length,
+         dragStartBehavior: dragStartBehavior,
+       );
 
   /// Creates a scrollable, 2D array of widgets with tiles that each have a
   /// maximum cross-axis extent.
@@ -1385,18 +1389,19 @@ class GridView extends BoxScrollView {
          addAutomaticKeepAlives: addAutomaticKeepAlives,
          addRepaintBoundaries: addRepaintBoundaries,
          addSemanticIndexes: addSemanticIndexes,
-       ), super(
-    key: key,
-    scrollDirection: scrollDirection,
-    reverse: reverse,
-    controller: controller,
-    primary: primary,
-    physics: physics,
-    shrinkWrap: shrinkWrap,
-    padding: padding,
-    semanticChildCount: semanticChildCount ?? children.length,
-    dragStartBehavior: dragStartBehavior,
-  );
+       ),
+       super(
+         key: key,
+         scrollDirection: scrollDirection,
+         reverse: reverse,
+         controller: controller,
+         primary: primary,
+         physics: physics,
+         shrinkWrap: shrinkWrap,
+         padding: padding,
+         semanticChildCount: semanticChildCount ?? children.length,
+         dragStartBehavior: dragStartBehavior,
+       );
 
   /// A delegate that controls the layout of the children within the [GridView].
   ///
diff --git a/packages/flutter/lib/src/widgets/scrollable.dart b/packages/flutter/lib/src/widgets/scrollable.dart
index 4af767fbec..f0f723dcc0 100644
--- a/packages/flutter/lib/src/widgets/scrollable.dart
+++ b/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);
   }
 
diff --git a/packages/flutter/lib/src/widgets/sliver_prototype_extent_list.dart b/packages/flutter/lib/src/widgets/sliver_prototype_extent_list.dart
index 2cfab2a5c7..77455eeae5 100644
--- a/packages/flutter/lib/src/widgets/sliver_prototype_extent_list.dart
+++ b/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.
   ///
diff --git a/packages/flutter/lib/src/widgets/spacer.dart b/packages/flutter/lib/src/widgets/spacer.dart
index 2f88dd9ae8..0d94071e39 100644
--- a/packages/flutter/lib/src/widgets/spacer.dart
+++ b/packages/flutter/lib/src/widgets/spacer.dart
@@ -43,9 +43,9 @@ class Spacer extends StatelessWidget {
   ///
   /// The [flex] parameter may not be null or less than one.
   const Spacer({Key key, this.flex = 1})
-      : assert(flex != null),
-        assert(flex > 0),
-        super(key: key);
+    : assert(flex != null),
+      assert(flex > 0),
+      super(key: key);
 
   /// The flex factor to use in determining how much space to take up.
   ///
diff --git a/packages/flutter/lib/src/widgets/text.dart b/packages/flutter/lib/src/widgets/text.dart
index 683e80eb8b..d85b6700ef 100644
--- a/packages/flutter/lib/src/widgets/text.dart
+++ b/packages/flutter/lib/src/widgets/text.dart
@@ -248,9 +248,9 @@ class Text extends StatelessWidget {
     this.textScaleFactor,
     this.maxLines,
     this.semanticsLabel,
-  }): assert(textSpan != null),
-      data = null,
-      super(key: key);
+  }) : assert(textSpan != null),
+       data = null,
+       super(key: key);
 
   /// The text to display.
   ///
diff --git a/packages/flutter/lib/src/widgets/text_selection.dart b/packages/flutter/lib/src/widgets/text_selection.dart
index de99d16b6f..0351213261 100644
--- a/packages/flutter/lib/src/widgets/text_selection.dart
+++ b/packages/flutter/lib/src/widgets/text_selection.dart
@@ -231,9 +231,9 @@ class TextSelectionOverlay {
     this.selectionControls,
     this.selectionDelegate,
     this.dragStartBehavior = DragStartBehavior.down,
-  }): assert(value != null),
-      assert(context != null),
-      _value = value {
+  }) : assert(value != null),
+       assert(context != null),
+       _value = value {
     final OverlayState overlay = Overlay.of(context);
     assert(overlay != null);
     _handleController = AnimationController(duration: _fadeDuration, vsync: overlay);
diff --git a/packages/flutter/lib/src/widgets/texture.dart b/packages/flutter/lib/src/widgets/texture.dart
index 03d2cc3ccc..2e97f8eaed 100644
--- a/packages/flutter/lib/src/widgets/texture.dart
+++ b/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;
diff --git a/packages/flutter/lib/src/widgets/widget_inspector.dart b/packages/flutter/lib/src/widgets/widget_inspector.dart
index 312fbe61d2..3d65db87e7 100644
--- a/packages/flutter/lib/src/widgets/widget_inspector.dart
+++ b/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;
@@ -686,13 +691,12 @@ class _SerializeConfig {
     _SerializeConfig base, {
     int subtreeDepth,
     Iterable<Diagnosticable> pathToInclude,
-  }) :
-    groupName = base.groupName,
-    summaryTree = base.summaryTree,
-    subtreeDepth = subtreeDepth ?? base.subtreeDepth,
-    pathToInclude = pathToInclude ?? base.pathToInclude,
-    includeProperties = base.includeProperties,
-    expandPropertyValues = base.expandPropertyValues;
+  }) : groupName = base.groupName,
+       summaryTree = base.summaryTree,
+       subtreeDepth = subtreeDepth ?? base.subtreeDepth,
+       pathToInclude = pathToInclude ?? base.pathToInclude,
+       includeProperties = base.includeProperties,
+       expandPropertyValues = base.expandPropertyValues;
 
   /// Optional object group name used to manage manage lifetimes of object
   /// references in the returned JSON.
@@ -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;
@@ -2476,9 +2482,9 @@ class _RenderInspectorOverlay extends RenderBox {
 }
 
 class _TransformedRect {
-  _TransformedRect(RenderObject object) :
-    rect = object.semanticBounds,
-    transform = object.getTransformTo(null);
+  _TransformedRect(RenderObject object)
+    : rect = object.semanticBounds,
+      transform = object.getTransformTo(null);
 
   final Rect rect;
   final Matrix4 transform;
@@ -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;
diff --git a/packages/flutter/test/painting/image_stream_test.dart b/packages/flutter/test/painting/image_stream_test.dart
index bc3f30adac..e78843a9bd 100644
--- a/packages/flutter/test/painting/image_stream_test.dart
+++ b/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) :
-    _image = FakeImage(width, height);
+  FakeFrameInfo(int width, int height, this._duration)
+    : _image = FakeImage(width, height);
 
   final Duration _duration;
   final Image _image;
diff --git a/packages/flutter/test/rendering/mock_canvas.dart b/packages/flutter/test/rendering/mock_canvas.dart
index 805232a92c..d51378010a 100644
--- a/packages/flutter/test/rendering/mock_canvas.dart
+++ b/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;
diff --git a/packages/flutter_driver/lib/src/common/find.dart b/packages/flutter_driver/lib/src/common/find.dart
index b24b569fa9..690437174c 100644
--- a/packages/flutter_driver/lib/src/common/find.dart
+++ b/packages/flutter_driver/lib/src/common/find.dart
@@ -27,8 +27,8 @@ abstract class CommandWithTarget extends Command {
 
   /// Deserializes this command from the value generated by [serialize].
   CommandWithTarget.deserialize(Map<String, String> json)
-      : finder = SerializableFinder.deserialize(json),
-        super.deserialize(json);
+    : finder = SerializableFinder.deserialize(json),
+      super.deserialize(json);
 
   /// Locates the object or objects targeted by this command.
   final SerializableFinder finder;
@@ -53,7 +53,7 @@ class WaitFor extends CommandWithTarget {
   ///
   /// If [timeout] is not specified the command times out after 5 seconds.
   WaitFor(SerializableFinder finder, {Duration timeout})
-      : super(finder, timeout: timeout);
+    : super(finder, timeout: timeout);
 
   /// Deserializes this command from the value generated by [serialize].
   WaitFor.deserialize(Map<String, String> json) : super.deserialize(json);
@@ -80,7 +80,7 @@ class WaitForAbsent extends CommandWithTarget {
   ///
   /// If [timeout] is not specified the command times out after 5 seconds.
   WaitForAbsent(SerializableFinder finder, {Duration timeout})
-      : super(finder, timeout: timeout);
+    : super(finder, timeout: timeout);
 
   /// Deserializes this command from the value generated by [serialize].
   WaitForAbsent.deserialize(Map<String, String> json) : super.deserialize(json);
@@ -107,7 +107,7 @@ class WaitUntilNoTransientCallbacks extends Command {
 
   /// Deserializes this command from the value generated by [serialize].
   WaitUntilNoTransientCallbacks.deserialize(Map<String, String> json)
-      : super.deserialize(json);
+    : super.deserialize(json);
 
   @override
   final String kind = 'waitUntilNoTransientCallbacks';
@@ -191,8 +191,8 @@ class ByText extends SerializableFinder {
 class ByValueKey extends SerializableFinder {
   /// Creates a finder given the key value.
   ByValueKey(this.keyValue)
-    : keyValueString = '$keyValue',
-      keyValueType = '${keyValue.runtimeType}' {
+      : keyValueString = '$keyValue',
+        keyValueType = '${keyValue.runtimeType}' {
     if (!_supportedKeyValueTypes.contains(keyValue.runtimeType))
       throw _createInvalidKeyValueTypeError('$keyValue.runtimeType');
   }
@@ -284,7 +284,7 @@ class GetSemanticsId extends CommandWithTarget {
 
   /// Creates a command from a json map.
   GetSemanticsId.deserialize(Map<String, String> json)
-      : super.deserialize(json);
+    : super.deserialize(json);
 
   @override
   String get kind => 'get_semantics_id';
diff --git a/packages/flutter_driver/lib/src/common/frame_sync.dart b/packages/flutter_driver/lib/src/common/frame_sync.dart
index 114a55a113..add70fb455 100644
--- a/packages/flutter_driver/lib/src/common/frame_sync.dart
+++ b/packages/flutter_driver/lib/src/common/frame_sync.dart
@@ -11,8 +11,8 @@ class SetFrameSync extends Command {
 
   /// Deserializes this command from the value generated by [serialize].
   SetFrameSync.deserialize(Map<String, String> params)
-      : enabled = params['enabled'].toLowerCase() == 'true',
-        super.deserialize(params);
+    : enabled = params['enabled'].toLowerCase() == 'true',
+      super.deserialize(params);
 
   /// Whether frameSync should be enabled or disabled.
   final bool enabled;
diff --git a/packages/flutter_driver/lib/src/common/gesture.dart b/packages/flutter_driver/lib/src/common/gesture.dart
index 6da0b1dd52..7dabd3f57a 100644
--- a/packages/flutter_driver/lib/src/common/gesture.dart
+++ b/packages/flutter_driver/lib/src/common/gesture.dart
@@ -44,11 +44,11 @@ class Scroll extends CommandWithTarget {
 
   /// Deserializes this command from the value generated by [serialize].
   Scroll.deserialize(Map<String, String> json)
-      : dx = double.parse(json['dx']),
-        dy = double.parse(json['dy']),
-        duration = Duration(microseconds: int.parse(json['duration'])),
-        frequency = int.parse(json['frequency']),
-        super.deserialize(json);
+    : dx = double.parse(json['dx']),
+      dy = double.parse(json['dy']),
+      duration = Duration(microseconds: int.parse(json['duration'])),
+      frequency = int.parse(json['frequency']),
+      super.deserialize(json);
 
   /// Delta X offset per move event.
   final double dx;
@@ -94,8 +94,8 @@ class ScrollIntoView extends CommandWithTarget {
 
   /// Deserializes this command from the value generated by [serialize].
   ScrollIntoView.deserialize(Map<String, String> json)
-      : alignment = double.parse(json['alignment']),
-        super.deserialize(json);
+    : alignment = double.parse(json['alignment']),
+      super.deserialize(json);
 
   /// How the widget should be aligned.
   ///
diff --git a/packages/flutter_driver/lib/src/common/message.dart b/packages/flutter_driver/lib/src/common/message.dart
index f66d14804e..0b510103e2 100644
--- a/packages/flutter_driver/lib/src/common/message.dart
+++ b/packages/flutter_driver/lib/src/common/message.dart
@@ -13,7 +13,7 @@ abstract class Command {
 
   /// Deserializes this command from the value generated by [serialize].
   Command.deserialize(Map<String, String> json)
-      : timeout = _parseTimeout(json);
+    : timeout = _parseTimeout(json);
 
   static Duration _parseTimeout(Map<String, String> json) {
     final String timeout = json['timeout'];
diff --git a/packages/flutter_driver/lib/src/common/request_data.dart b/packages/flutter_driver/lib/src/common/request_data.dart
index d9b6598a30..d6d64e2777 100644
--- a/packages/flutter_driver/lib/src/common/request_data.dart
+++ b/packages/flutter_driver/lib/src/common/request_data.dart
@@ -12,8 +12,8 @@ class RequestData extends Command {
 
   /// Deserializes this command from the value generated by [serialize].
   RequestData.deserialize(Map<String, String> params)
-      : message = params['message'],
-        super.deserialize(params);
+    : message = params['message'],
+      super.deserialize(params);
 
   /// The message being sent from the test to the application.
   final String message;
diff --git a/packages/flutter_driver/lib/src/common/semantics.dart b/packages/flutter_driver/lib/src/common/semantics.dart
index 048c3d0857..d44c42089c 100644
--- a/packages/flutter_driver/lib/src/common/semantics.dart
+++ b/packages/flutter_driver/lib/src/common/semantics.dart
@@ -11,8 +11,8 @@ class SetSemantics extends Command {
 
   /// Deserializes this command from the value generated by [serialize].
   SetSemantics.deserialize(Map<String, String> params)
-      : enabled = params['enabled'].toLowerCase() == 'true',
-        super.deserialize(params);
+    : enabled = params['enabled'].toLowerCase() == 'true',
+      super.deserialize(params);
 
   /// Whether semantics should be enabled (true) or disabled (false).
   final bool enabled;
diff --git a/packages/flutter_driver/lib/src/common/text.dart b/packages/flutter_driver/lib/src/common/text.dart
index 328c92d0c3..b5ee236bee 100644
--- a/packages/flutter_driver/lib/src/common/text.dart
+++ b/packages/flutter_driver/lib/src/common/text.dart
@@ -43,8 +43,8 @@ class EnterText extends Command {
 
   /// Deserializes this command from the value generated by [serialize].
   EnterText.deserialize(Map<String, dynamic> json)
-      : text = json['text'],
-        super.deserialize(json);
+    : text = json['text'],
+      super.deserialize(json);
 
   /// The text extracted by the [GetText] command.
   final String text;
@@ -79,8 +79,8 @@ class SetTextEntryEmulation extends Command {
 
   /// Deserializes this command from the value generated by [serialize].
   SetTextEntryEmulation.deserialize(Map<String, dynamic> json)
-      : enabled = json['enabled'] == 'true',
-        super.deserialize(json);
+    : enabled = json['enabled'] == 'true',
+      super.deserialize(json);
 
   /// Whether text entry emulation should be enabled.
   final bool enabled;
diff --git a/packages/flutter_test/lib/src/accessibility.dart b/packages/flutter_test/lib/src/accessibility.dart
index 97a269d5c3..9676c585c6 100644
--- a/packages/flutter_test/lib/src/accessibility.dart
+++ b/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.
diff --git a/packages/flutter_test/lib/src/finders.dart b/packages/flutter_test/lib/src/finders.dart
index 2d41b0334c..a2fda53ded 100644
--- a/packages/flutter_test/lib/src/finders.dart
+++ b/packages/flutter_test/lib/src/finders.dart
@@ -576,8 +576,8 @@ class _WidgetFinder extends MatchFinder {
 
 class _WidgetPredicateFinder extends MatchFinder {
   _WidgetPredicateFinder(this.predicate, { String description, bool skipOffstage = true })
-      : _description = description,
-        super(skipOffstage: skipOffstage);
+    : _description = description,
+      super(skipOffstage: skipOffstage);
 
   final WidgetPredicate predicate;
   final String _description;
@@ -593,8 +593,8 @@ class _WidgetPredicateFinder extends MatchFinder {
 
 class _ElementPredicateFinder extends MatchFinder {
   _ElementPredicateFinder(this.predicate, { String description, bool skipOffstage = true })
-      : _description = description,
-        super(skipOffstage: skipOffstage);
+    : _description = description,
+      super(skipOffstage: skipOffstage);
 
   final ElementPredicate predicate;
   final String _description;
diff --git a/packages/flutter_test/lib/src/goldens.dart b/packages/flutter_test/lib/src/goldens.dart
index dd63f6fe04..fb2a208943 100644
--- a/packages/flutter_test/lib/src/goldens.dart
+++ b/packages/flutter_test/lib/src/goldens.dart
@@ -149,8 +149,8 @@ class LocalFileComparator implements GoldenFileComparator {
   ///
   /// The [testFile] URL must represent a file.
   LocalFileComparator(Uri testFile, {path.Style pathStyle})
-      : basedir = _getBasedir(testFile, pathStyle),
-        _path = _getPath(pathStyle);
+    : basedir = _getBasedir(testFile, pathStyle),
+      _path = _getPath(pathStyle);
 
   static path.Context _getPath(path.Style style) {
     return path.Context(style: style ?? path.Style.platform);
diff --git a/packages/flutter_test/lib/src/test_compat.dart b/packages/flutter_test/lib/src/test_compat.dart
index 7334274269..d1688b7759 100644
--- a/packages/flutter_test/lib/src/test_compat.dart
+++ b/packages/flutter_test/lib/src/test_compat.dart
@@ -304,12 +304,13 @@ void tearDownAll(Function body) {
 /// fixed, this must not import `dart:io`.
 class _Reporter {
   _Reporter({bool color = true, bool printPath = true})
-  : _printPath = printPath,
-    _green = color ? '\u001b[32m' : '',
-    _red = color ? '\u001b[31m' : '',
-    _yellow = color ? '\u001b[33m' : '',
-    _bold = color ? '\u001b[1m' : '',
-    _noColor = color ? '\u001b[0m' : '';
+    : _printPath = printPath,
+      _green = color ? '\u001b[32m' : '',
+      _red = color ? '\u001b[31m' : '',
+      _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>[];
diff --git a/packages/flutter_tools/lib/src/android/android_emulator.dart b/packages/flutter_tools/lib/src/android/android_emulator.dart
index bce406251a..5d6daf854f 100644
--- a/packages/flutter_tools/lib/src/android/android_emulator.dart
+++ b/packages/flutter_tools/lib/src/android/android_emulator.dart
@@ -27,7 +27,7 @@ class AndroidEmulators extends EmulatorDiscovery {
 
 class AndroidEmulator extends Emulator {
   AndroidEmulator(String id, [this._properties])
-      : super(id, _properties != null && _properties.isNotEmpty);
+    : super(id, _properties != null && _properties.isNotEmpty);
 
   Map<String, String> _properties;
 
diff --git a/packages/flutter_tools/lib/src/android/android_workflow.dart b/packages/flutter_tools/lib/src/android/android_workflow.dart
index 00431f0ab4..2ac566f163 100644
--- a/packages/flutter_tools/lib/src/android/android_workflow.dart
+++ b/packages/flutter_tools/lib/src/android/android_workflow.dart
@@ -51,7 +51,7 @@ class AndroidWorkflow implements Workflow {
 }
 
 class AndroidValidator extends DoctorValidator {
-  AndroidValidator(): super('Android toolchain - develop for Android devices',);
+  AndroidValidator() : super('Android toolchain - develop for Android devices',);
 
   @override
   String get slowWarning => '${_task ?? 'This'} is taking a long time...';
@@ -167,7 +167,7 @@ class AndroidValidator extends DoctorValidator {
 }
 
 class AndroidLicenseValidator extends DoctorValidator {
-  AndroidLicenseValidator(): super('Android license subvalidator',);
+  AndroidLicenseValidator() : super('Android license subvalidator',);
 
   @override
   String get slowWarning => 'Checking Android licenses is taking an unexpectedly long time...';
diff --git a/packages/flutter_tools/lib/src/artifacts.dart b/packages/flutter_tools/lib/src/artifacts.dart
index 371a04244d..6cfb8bcd9a 100644
--- a/packages/flutter_tools/lib/src/artifacts.dart
+++ b/packages/flutter_tools/lib/src/artifacts.dart
@@ -76,9 +76,11 @@ String _artifactToFileName(Artifact artifact, [TargetPlatform platform, BuildMod
 }
 
 class EngineBuildPaths {
-  const EngineBuildPaths({ @required this.targetEngine, @required this.hostEngine }):
-      assert(targetEngine != null),
-      assert(hostEngine != null);
+  const EngineBuildPaths({
+    @required this.targetEngine,
+    @required this.hostEngine,
+  }) : assert(targetEngine != null),
+       assert(hostEngine != null);
 
   final String targetEngine;
   final String hostEngine;
diff --git a/packages/flutter_tools/lib/src/base/process.dart b/packages/flutter_tools/lib/src/base/process.dart
index 40e085e69b..077b32e893 100644
--- a/packages/flutter_tools/lib/src/base/process.dart
+++ b/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;
 
diff --git a/packages/flutter_tools/lib/src/base/terminal.dart b/packages/flutter_tools/lib/src/base/terminal.dart
index de7f012940..8f9eb45e7e 100644
--- a/packages/flutter_tools/lib/src/base/terminal.dart
+++ b/packages/flutter_tools/lib/src/base/terminal.dart
@@ -42,9 +42,9 @@ class OutputPreferences {
     bool wrapText,
     int wrapColumn,
     bool showColor,
-  })  : wrapText = wrapText ?? io.stdio?.hasTerminal ?? const io.Stdio().hasTerminal,
-        _overrideWrapColumn = wrapColumn,
-        showColor = showColor ?? platform.stdoutSupportsAnsi ?? false;
+  }) : wrapText = wrapText ?? io.stdio?.hasTerminal ?? const io.Stdio().hasTerminal,
+       _overrideWrapColumn = wrapColumn,
+       showColor = showColor ?? platform.stdoutSupportsAnsi ?? false;
 
   /// If [wrapText] is true, then any text sent to the context's [Logger]
   /// instance (e.g. from the [printError] or [printStatus] functions) will be
diff --git a/packages/flutter_tools/lib/src/cache.dart b/packages/flutter_tools/lib/src/cache.dart
index dd1db595d1..fe5089ecb8 100644
--- a/packages/flutter_tools/lib/src/cache.dart
+++ b/packages/flutter_tools/lib/src/cache.dart
@@ -348,7 +348,7 @@ void _maybeWarnAboutStorageOverride(String overrideUrl) {
 
 /// A cached artifact containing fonts used for Material Design.
 class MaterialFonts extends CachedArtifact {
-  MaterialFonts(Cache cache): super('material_fonts', cache);
+  MaterialFonts(Cache cache) : super('material_fonts', cache);
 
   @override
   Future<void> updateInner() {
@@ -359,7 +359,7 @@ class MaterialFonts extends CachedArtifact {
 
 /// A cached artifact containing the Flutter engine binaries.
 class FlutterEngine extends CachedArtifact {
-  FlutterEngine(Cache cache): super('engine', cache);
+  FlutterEngine(Cache cache) : super('engine', cache);
 
   List<String> _getPackageDirs() => const <String>['sky_engine'];
 
@@ -574,7 +574,7 @@ class FlutterEngine extends CachedArtifact {
 
 /// A cached artifact containing Gradle Wrapper scripts and binaries.
 class GradleWrapper extends CachedArtifact {
-  GradleWrapper(Cache cache): super('gradle_wrapper', cache);
+  GradleWrapper(Cache cache) : super('gradle_wrapper', cache);
 
   List<String> get _gradleScripts => <String>['gradlew', 'gradlew.bat'];
 
diff --git a/packages/flutter_tools/lib/src/commands/update_packages.dart b/packages/flutter_tools/lib/src/commands/update_packages.dart
index efe4d91d48..f1f9d3d8a1 100644
--- a/packages/flutter_tools/lib/src/commands/update_packages.dart
+++ b/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:
diff --git a/packages/flutter_tools/lib/src/compile.dart b/packages/flutter_tools/lib/src/compile.dart
index 29fa0c6b75..3a24d54209 100644
--- a/packages/flutter_tools/lib/src/compile.dart
+++ b/packages/flutter_tools/lib/src/compile.dart
@@ -286,9 +286,13 @@ abstract class _CompilationRequest {
 }
 
 class _RecompileRequest extends _CompilationRequest {
-  _RecompileRequest(Completer<CompilerOutput> completer, this.mainPath,
-      this.invalidatedFiles, this.outputPath, this.packagesFilePath) :
-      super(completer);
+  _RecompileRequest(
+    Completer<CompilerOutput> 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,
-      this.typeDefinitions, this.libraryUri, this.klass, this.isStatic) :
-      super(completer);
+  _CompileExpressionRequest(
+    Completer<CompilerOutput> completer,
+    this.expression,
+    this.definitions,
+    this.typeDefinitions,
+    this.libraryUri,
+    this.klass,
+    this.isStatic
+  ) : super(completer);
 
   String expression;
   List<String> definitions;
diff --git a/packages/flutter_tools/lib/src/dart/dependencies.dart b/packages/flutter_tools/lib/src/dart/dependencies.dart
index 0b7fa12077..f931b0936a 100644
--- a/packages/flutter_tools/lib/src/dart/dependencies.dart
+++ b/packages/flutter_tools/lib/src/dart/dependencies.dart
@@ -26,10 +26,10 @@ String _dottedNameToString(analyzer.DottedName dottedName) {
 }
 
 class DartDependencySetBuilder {
-  DartDependencySetBuilder(String mainScriptPath, String packagesFilePath) :
-    _mainScriptPath = canonicalizePath(mainScriptPath),
-    _mainScriptUri = fs.path.toUri(mainScriptPath),
-    _packagesFilePath = canonicalizePath(packagesFilePath);
+  DartDependencySetBuilder(String mainScriptPath, String packagesFilePath)
+    : _mainScriptPath = canonicalizePath(mainScriptPath),
+      _mainScriptUri = fs.path.toUri(mainScriptPath),
+      _packagesFilePath = canonicalizePath(packagesFilePath);
 
   final String _mainScriptPath;
   final String _packagesFilePath;
diff --git a/packages/flutter_tools/lib/src/devfs.dart b/packages/flutter_tools/lib/src/devfs.dart
index 75ebec8abc..dece8571cb 100644
--- a/packages/flutter_tools/lib/src/devfs.dart
+++ b/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;
 
@@ -274,7 +276,7 @@ class DevFSException implements Exception {
 
 class _DevFSHttpWriter {
   _DevFSHttpWriter(this.fsName, VMService serviceProtocol)
-      : httpAddress = serviceProtocol.httpAddress;
+    : httpAddress = serviceProtocol.httpAddress;
 
   final String fsName;
   final Uri httpAddress;
@@ -377,25 +379,25 @@ class UpdateFSReport {
 
 class DevFS {
   /// Create a [DevFS] named [fsName] for the local files in [rootDirectory].
-  DevFS(VMService serviceProtocol,
-        this.fsName,
-        this.rootDirectory, {
-        String packagesFilePath
-      })
-    : _operations = ServiceProtocolDevFSOperations(serviceProtocol),
-      _httpWriter = _DevFSHttpWriter(fsName, serviceProtocol) {
+  DevFS(
+    VMService serviceProtocol,
+    this.fsName,
+    this.rootDirectory, {
+    String packagesFilePath
+  }) : _operations = ServiceProtocolDevFSOperations(serviceProtocol),
+       _httpWriter = _DevFSHttpWriter(fsName, serviceProtocol) {
     _packagesFilePath =
         packagesFilePath ?? fs.path.join(rootDirectory.path, kPackagesFileName);
   }
 
-  DevFS.operations(this._operations,
-                   this.fsName,
-                   this.rootDirectory, {
-                   String packagesFilePath,
-      })
-    : _httpWriter = null {
-    _packagesFilePath =
-        packagesFilePath ?? fs.path.join(rootDirectory.path, kPackagesFileName);
+  DevFS.operations(
+    this._operations,
+    this.fsName,
+    this.rootDirectory, {
+    String packagesFilePath,
+  }) : _httpWriter = null {
+       _packagesFilePath =
+           packagesFilePath ?? fs.path.join(rootDirectory.path, kPackagesFileName);
   }
 
   final DevFSOperations _operations;
diff --git a/packages/flutter_tools/lib/src/device.dart b/packages/flutter_tools/lib/src/device.dart
index 9d46ffe2f9..d932fd469d 100644
--- a/packages/flutter_tools/lib/src/device.dart
+++ b/packages/flutter_tools/lib/src/device.dart
@@ -361,15 +361,15 @@ class DebuggingOptions {
     this.observatoryPort,
    }) : debuggingEnabled = true;
 
-  DebuggingOptions.disabled(this.buildInfo) :
-    debuggingEnabled = false,
-    useTestFonts = false,
-    startPaused = false,
-    enableSoftwareRendering = false,
-    skiaDeterministicRendering = false,
-    traceSkia = false,
-    traceSystrace = false,
-    observatoryPort = null;
+  DebuggingOptions.disabled(this.buildInfo)
+    : debuggingEnabled = false,
+      useTestFonts = false,
+      startPaused = false,
+      enableSoftwareRendering = false,
+      skiaDeterministicRendering = false,
+      traceSkia = false,
+      traceSystrace = false,
+      observatoryPort = null;
 
   final bool debuggingEnabled;
 
@@ -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;
 
diff --git a/packages/flutter_tools/lib/src/ios/devices.dart b/packages/flutter_tools/lib/src/ios/devices.dart
index d250ea0292..a68bcfbb93 100644
--- a/packages/flutter_tools/lib/src/ios/devices.dart
+++ b/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');
   }
diff --git a/packages/flutter_tools/lib/src/project.dart b/packages/flutter_tools/lib/src/project.dart
index 5ac90fba6a..4c5496bea2 100644
--- a/packages/flutter_tools/lib/src/project.dart
+++ b/packages/flutter_tools/lib/src/project.dart
@@ -31,9 +31,9 @@ import 'template.dart';
 class FlutterProject {
   @visibleForTesting
   FlutterProject(this.directory, this.manifest, this._exampleManifest)
-      : assert(directory != null),
-        assert(manifest != null),
-        assert(_exampleManifest != null);
+    : assert(directory != null),
+      assert(manifest != null),
+      assert(_exampleManifest != null);
 
   /// Returns a future that completes with a [FlutterProject] view of the given directory
   /// or a ToolExit error, if `pubspec.yaml` or `example/pubspec.yaml` is invalid.
diff --git a/packages/flutter_tools/lib/src/tester/flutter_tester.dart b/packages/flutter_tools/lib/src/tester/flutter_tester.dart
index de296008e8..30861beae1 100644
--- a/packages/flutter_tools/lib/src/tester/flutter_tester.dart
+++ b/packages/flutter_tools/lib/src/tester/flutter_tester.dart
@@ -27,8 +27,8 @@ class FlutterTesterApp extends ApplicationPackage {
   }
 
   FlutterTesterApp._(Directory directory)
-      : _directory = directory,
-        super(id: directory.path);
+    : _directory = directory,
+      super(id: directory.path);
 
   final Directory _directory;
 
diff --git a/packages/flutter_tools/lib/src/version.dart b/packages/flutter_tools/lib/src/version.dart
index 29dbc5ed40..bd65cc3151 100644
--- a/packages/flutter_tools/lib/src/version.dart
+++ b/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;
diff --git a/packages/flutter_tools/lib/src/vmservice_record_replay.dart b/packages/flutter_tools/lib/src/vmservice_record_replay.dart
index 0061fd4209..086868222e 100644
--- a/packages/flutter_tools/lib/src/vmservice_record_replay.dart
+++ b/packages/flutter_tools/lib/src/vmservice_record_replay.dart
@@ -195,7 +195,7 @@ class _RecordingSink implements StreamSink<String> {
 /// replays the corresponding responses back from the recording.
 class ReplayVMServiceChannel extends StreamChannelMixin<String> {
   ReplayVMServiceChannel(Directory location)
-      : _transactions = _loadTransactions(location);
+    : _transactions = _loadTransactions(location);
 
   final Map<int, _Transaction> _transactions;
   final StreamController<String> _controller = StreamController<String>();
diff --git a/packages/flutter_tools/test/commands/doctor_test.dart b/packages/flutter_tools/test/commands/doctor_test.dart
index 95c9141ffc..0a403cc4cd 100644
--- a/packages/flutter_tools/test/commands/doctor_test.dart
+++ b/packages/flutter_tools/test/commands/doctor_test.dart
@@ -477,7 +477,7 @@ class PassingValidator extends DoctorValidator {
 }
 
 class MissingValidator extends DoctorValidator {
-  MissingValidator(): super('Missing Validator');
+  MissingValidator() : super('Missing Validator');
 
   @override
   Future<ValidationResult> validate() async {
@@ -490,7 +490,7 @@ class MissingValidator extends DoctorValidator {
 }
 
 class NotAvailableValidator extends DoctorValidator {
-  NotAvailableValidator(): super('Not Available Validator');
+  NotAvailableValidator() : super('Not Available Validator');
 
   @override
   Future<ValidationResult> validate() async {
@@ -622,7 +622,7 @@ class PassingGroupedValidator extends DoctorValidator {
 }
 
 class MissingGroupedValidator extends DoctorValidator {
-  MissingGroupedValidator(String name): super(name);
+  MissingGroupedValidator(String name) : super(name);
 
   @override
   Future<ValidationResult> validate() async {
@@ -633,7 +633,7 @@ class MissingGroupedValidator extends DoctorValidator {
 }
 
 class PartialGroupedValidator extends DoctorValidator {
-  PartialGroupedValidator(String name): super(name);
+  PartialGroupedValidator(String name) : super(name);
 
   @override
   Future<ValidationResult> validate() async {
@@ -702,7 +702,7 @@ class FakeSmallGroupDoctor extends Doctor {
 
 class VsCodeValidatorTestTargets extends VsCodeValidator {
   VsCodeValidatorTestTargets._(String installDirectory, String extensionDirectory, {String edition})
-      : super(VsCode.fromDirectory(installDirectory, extensionDirectory, edition: edition));
+    : super(VsCode.fromDirectory(installDirectory, extensionDirectory, edition: edition));
 
   static VsCodeValidatorTestTargets get installedWithExtension =>
       VsCodeValidatorTestTargets._(validInstall, validExtensions);
diff --git a/packages/flutter_tools/test/emulator_test.dart b/packages/flutter_tools/test/emulator_test.dart
index 7a7c5b4bd1..71469fb357 100644
--- a/packages/flutter_tools/test/emulator_test.dart
+++ b/packages/flutter_tools/test/emulator_test.dart
@@ -164,7 +164,7 @@ class TestEmulatorManager extends EmulatorManager {
 
 class _MockEmulator extends Emulator {
   _MockEmulator(String id, this.name, this.manufacturer, this.label)
-      : super(id, true);
+    : super(id, true);
 
   @override
   final String name;
diff --git a/packages/flutter_tools/test/integration/test_driver.dart b/packages/flutter_tools/test/integration/test_driver.dart
index 01482961ca..b95e2c20ab 100644
--- a/packages/flutter_tools/test/integration/test_driver.dart
+++ b/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}):
-    super(_projectFolder, logPrefix: logPrefix);
+  FlutterTestTestDriver(Directory _projectFolder, {String logPrefix})
+    : super(_projectFolder, logPrefix: logPrefix);
 
   Future<void> test({
     String testFile = 'test/test.dart',
diff --git a/packages/flutter_tools/test/resident_runner_test.dart b/packages/flutter_tools/test/resident_runner_test.dart
index 815de9309b..2a20530991 100644
--- a/packages/flutter_tools/test/resident_runner_test.dart
+++ b/packages/flutter_tools/test/resident_runner_test.dart
@@ -12,7 +12,7 @@ import 'src/context.dart';
 
 class TestRunner extends ResidentRunner {
   TestRunner(List<FlutterDevice> devices)
-      : super(devices);
+    : super(devices);
 
   bool hasHelpBeenPrinted = false;
   String receivedCommand;
diff --git a/packages/fuchsia_remote_debug_protocol/lib/src/common/logging.dart b/packages/fuchsia_remote_debug_protocol/lib/src/common/logging.dart
index 8a1e6662ae..230ad3fbcd 100644
--- a/packages/fuchsia_remote_debug_protocol/lib/src/common/logging.dart
+++ b/packages/fuchsia_remote_debug_protocol/lib/src/common/logging.dart
@@ -69,9 +69,8 @@ class LogMessage {
   ///
   /// When this message is created, it sets its [time] to [DateTime.now].
   LogMessage(this.message, this.tag, this.level)
-      : levelName =
-            level.toString().substring(level.toString().indexOf('.') + 1),
-        time = DateTime.now();
+    : levelName = level.toString().substring(level.toString().indexOf('.') + 1),
+      time = DateTime.now();
 
   /// The actual log message.
   final String message;
diff --git a/packages/fuchsia_remote_debug_protocol/lib/src/fuchsia_remote_connection.dart b/packages/fuchsia_remote_debug_protocol/lib/src/fuchsia_remote_connection.dart
index 1965752ac4..d44308c14d 100644
--- a/packages/fuchsia_remote_debug_protocol/lib/src/fuchsia_remote_connection.dart
+++ b/packages/fuchsia_remote_debug_protocol/lib/src/fuchsia_remote_connection.dart
@@ -101,7 +101,7 @@ class DartVmEvent {
 /// Dart VM at any given time.
 class FuchsiaRemoteConnection {
   FuchsiaRemoteConnection._(this._useIpV6Loopback, this._sshCommandRunner)
-      : _pollDartVms = false;
+    : _pollDartVms = false;
 
   bool _pollDartVms;
   final List<PortForwarder> _forwardedVmServicePorts = <PortForwarder>[];