diff --git a/examples/layers/services/media_service.dart b/examples/layers/services/media_service.dart
index 02e914f..f7f234d 100644
--- a/examples/layers/services/media_service.dart
+++ b/examples/layers/services/media_service.dart
@@ -121,7 +121,7 @@
   );
 }
 
-main() async {
+Future main() async {
   runApp(splashScreen());
 
   PianoApp app = new PianoApp();
diff --git a/examples/stocks/test_driver/scroll_perf_test.dart b/examples/stocks/test_driver/scroll_perf_test.dart
index 62cb9e6..f5ba03a 100644
--- a/examples/stocks/test_driver/scroll_perf_test.dart
+++ b/examples/stocks/test_driver/scroll_perf_test.dart
@@ -6,7 +6,7 @@
 import 'package:flutter_driver/flutter_driver.dart';
 import 'package:test/test.dart';
 
-main() {
+void main() {
   group('scrolling performance test', () {
     FlutterDriver driver;
 
diff --git a/packages/cassowary/lib/param.dart b/packages/cassowary/lib/param.dart
index 29ae254..81d3496 100644
--- a/packages/cassowary/lib/param.dart
+++ b/packages/cassowary/lib/param.dart
@@ -23,7 +23,7 @@
   double get value => variable.value;
 
   String get name => variable.name;
-  set name(String name) { variable.name = name; }
+  void set name(String name) { variable.name = name; }
 
   Expression asExpression() => new Expression([new Term(variable, 1.0)], 0.0);
 }
diff --git a/packages/cassowary/lib/row.dart b/packages/cassowary/lib/row.dart
index 5c49c0c..49b8fb9 100644
--- a/packages/cassowary/lib/row.dart
+++ b/packages/cassowary/lib/row.dart
@@ -16,7 +16,7 @@
   double add(double value) => constant += value;
 
   void insertSymbol(_Symbol symbol, [double coefficient = 1.0]) {
-    double val = _elvis(cells[symbol], 0.0);
+    double val = cells[symbol] ?? 0.0;
 
     if (_nearZero(val + coefficient)) {
       cells.remove(symbol);
@@ -52,7 +52,7 @@
     solveForSymbol(rhs);
   }
 
-  double coefficientForSymbol(_Symbol symbol) => _elvis(cells[symbol], 0.0);
+  double coefficientForSymbol(_Symbol symbol) => cells[symbol] ?? 0.0;
 
   void substitute(_Symbol symbol, _Row row) {
     double coefficient = cells[symbol];
diff --git a/packages/cassowary/lib/solver.dart b/packages/cassowary/lib/solver.dart
index 35451a5..4e551cf 100644
--- a/packages/cassowary/lib/solver.dart
+++ b/packages/cassowary/lib/solver.dart
@@ -583,7 +583,7 @@
       }
     }
 
-    return _elvis(entering, new _Symbol(_SymbolType.invalid, 0));
+    return entering ?? new _Symbol(_SymbolType.invalid, 0);
   }
 
   String toString() {
diff --git a/packages/cassowary/lib/utils.dart b/packages/cassowary/lib/utils.dart
index 699a6ae..224e8e3 100644
--- a/packages/cassowary/lib/utils.dart
+++ b/packages/cassowary/lib/utils.dart
@@ -9,11 +9,6 @@
   return value < 0.0 ? -value < epsilon : value < epsilon;
 }
 
-// Workaround for the lack of a null coalescing operator. Uses a ternary
-// instead. Sadly, due the lack of generic types on functions, we have to use
-// dynamic instead.
-_elvis(a, b) => a != null ? a : b;
-
 class _Pair<X, Y> {
   X first;
   Y second;
diff --git a/packages/cassowary/lib/variable.dart b/packages/cassowary/lib/variable.dart
index eca7948..d362b87 100644
--- a/packages/cassowary/lib/variable.dart
+++ b/packages/cassowary/lib/variable.dart
@@ -21,7 +21,7 @@
     return res;
   }
 
-  String get debugName => _elvis(name, 'variable$_tick');
+  String get debugName => name ?? 'variable$_tick';
 
   @override
   String toString() => debugName;
diff --git a/packages/flutter/lib/src/widgets/binding.dart b/packages/flutter/lib/src/widgets/binding.dart
index 0b353bc..b0b8278 100644
--- a/packages/flutter/lib/src/widgets/binding.dart
+++ b/packages/flutter/lib/src/widgets/binding.dart
@@ -35,7 +35,7 @@
     return _instance;
   }
 
-  initInstances() {
+  void initInstances() {
     super.initInstances();
     _instance = this;
     BuildableElement.scheduleBuildFor = scheduleBuildFor;
diff --git a/packages/flutter/lib/src/widgets/semantics_debugger.dart b/packages/flutter/lib/src/widgets/semantics_debugger.dart
index 45e9250..8183b36 100644
--- a/packages/flutter/lib/src/widgets/semantics_debugger.dart
+++ b/packages/flutter/lib/src/widgets/semantics_debugger.dart
@@ -311,7 +311,7 @@
 
   int generation = 0;
 
-  updateSemanticsTree(List<mojom.SemanticsNode> nodes) {
+  void updateSemanticsTree(List<mojom.SemanticsNode> nodes) {
     generation += 1;
     for (mojom.SemanticsNode node in nodes)
       _updateNode(node);
diff --git a/packages/flutter/test/gestures/lsq_solver_test.dart b/packages/flutter/test/gestures/lsq_solver_test.dart
index 08246b5..c1ed191 100644
--- a/packages/flutter/test/gestures/lsq_solver_test.dart
+++ b/packages/flutter/test/gestures/lsq_solver_test.dart
@@ -7,7 +7,7 @@
 
 
 void main() {
-  approx(double value, double expectation) {
+  bool approx(double value, double expectation) {
     const double eps = 1e-6;
     return (value - expectation).abs() < eps;
   }
diff --git a/packages/flutter/test/widget/test_semantics.dart b/packages/flutter/test/widget/test_semantics.dart
index 7eda783..9fa4a32 100644
--- a/packages/flutter/test/widget/test_semantics.dart
+++ b/packages/flutter/test/widget/test_semantics.dart
@@ -10,7 +10,7 @@
     SemanticsNode.addListener(this);
   }
   final List<mojom.SemanticsNode> updates = <mojom.SemanticsNode>[];
-  updateSemanticsTree(List<mojom.SemanticsNode> nodes) {
+  void updateSemanticsTree(List<mojom.SemanticsNode> nodes) {
     assert(!nodes.any((mojom.SemanticsNode node) => node == null));
     updates.addAll(nodes);
     updates.add(null);
diff --git a/packages/flutter_driver/lib/src/find.dart b/packages/flutter_driver/lib/src/find.dart
index 11715eb..7e05334 100644
--- a/packages/flutter_driver/lib/src/find.dart
+++ b/packages/flutter_driver/lib/src/find.dart
@@ -7,6 +7,10 @@
 
 const List<Type> _supportedKeyValueTypes = const <Type>[String, int];
 
+DriverError _createInvalidKeyValueTypeError(String invalidType) {
+  return new DriverError('Unsupported key value type $invalidType. Flutter Driver only supports ${_supportedKeyValueTypes.join(", ")}');
+}
+
 /// Command to find an element.
 class Find extends Command {
   final String kind = 'find';
@@ -20,10 +24,6 @@
   static Find deserialize(Map<String, String> json) {
     return new Find(SearchSpecification.deserialize(json));
   }
-
-  static _throwInvalidKeyValueType(String invalidType) {
-    throw new DriverError('Unsupported key value type $invalidType. Flutter Driver only supports ${_supportedKeyValueTypes.join(", ")}');
-  }
 }
 
 /// Describes how to the driver should search for elements.
@@ -89,7 +89,7 @@
       this.keyValueString = '$keyValue',
       this.keyValueType = '${keyValue.runtimeType}' {
     if (!_supportedKeyValueTypes.contains(keyValue.runtimeType))
-      _throwInvalidKeyValueType('$keyValue.runtimeType');
+      throw _createInvalidKeyValueTypeError('$keyValue.runtimeType');
   }
 
   /// The true value of the key.
@@ -117,13 +117,9 @@
       case 'String':
         return new ByValueKey(keyValueString);
       default:
-        return _throwInvalidKeyValueType(keyValueType);
+        throw _createInvalidKeyValueTypeError(keyValueType);
     }
   }
-
-  static _throwInvalidKeyValueType(String invalidType) {
-    throw new DriverError('Unsupported key value type $invalidType. Flutter Driver only supports ${_supportedKeyValueTypes.join(", ")}');
-  }
 }
 
 /// Command to read the text from a given element.
diff --git a/packages/flutter_driver/lib/src/health.dart b/packages/flutter_driver/lib/src/health.dart
index d46a302..1fffbe9 100644
--- a/packages/flutter_driver/lib/src/health.dart
+++ b/packages/flutter_driver/lib/src/health.dart
@@ -9,7 +9,7 @@
 class GetHealth implements Command {
   final String kind = 'get_health';
 
-  static deserialize(Map<String, String> json) => new GetHealth();
+  static GetHealth deserialize(Map<String, String> json) => new GetHealth();
 
   Map<String, String> serialize() => const {};
 }
diff --git a/packages/flutter_driver/test/flutter_driver_test.dart b/packages/flutter_driver/test/flutter_driver_test.dart
index 4ed75da..3d7c118 100644
--- a/packages/flutter_driver/test/flutter_driver_test.dart
+++ b/packages/flutter_driver/test/flutter_driver_test.dart
@@ -13,7 +13,7 @@
 import 'package:quiver/testing/async.dart';
 import 'package:vm_service_client/vm_service_client.dart';
 
-main() {
+void main() {
   group('FlutterDriver.connect', () {
     List<LogRecord> log;
     StreamSubscription logSub;
@@ -21,7 +21,7 @@
     MockVM mockVM;
     MockIsolate mockIsolate;
 
-    expectLogContains(String message) {
+    void expectLogContains(String message) {
       expect(log.map((r) => '$r'), anyElement(contains(message)));
     }
 
diff --git a/packages/flutter_driver/test/retry_test.dart b/packages/flutter_driver/test/retry_test.dart
index d1e6f40..b4fa3fd 100644
--- a/packages/flutter_driver/test/retry_test.dart
+++ b/packages/flutter_driver/test/retry_test.dart
@@ -9,7 +9,7 @@
 
 import 'package:flutter_driver/src/retry.dart';
 
-main() {
+void main() {
   group('retry', () {
     FakeAsync fakeAsync;
 
diff --git a/packages/flutter_sprites/lib/src/action.dart b/packages/flutter_sprites/lib/src/action.dart
index cd6915b..fb1aa8a 100644
--- a/packages/flutter_sprites/lib/src/action.dart
+++ b/packages/flutter_sprites/lib/src/action.dart
@@ -125,7 +125,7 @@
   ///     var myInifiniteLoop = new ActionRepeatForever(myAction);
   ActionRepeatForever(this.action);
 
-  step(double dt) {
+  void step(double dt) {
     _elapsedInAction += dt;
     while (_elapsedInAction > action.duration) {
       _elapsedInAction -= action.duration;
diff --git a/packages/flutter_sprites/lib/src/effect_line.dart b/packages/flutter_sprites/lib/src/effect_line.dart
index 9af9050..1f94fce 100644
--- a/packages/flutter_sprites/lib/src/effect_line.dart
+++ b/packages/flutter_sprites/lib/src/effect_line.dart
@@ -67,7 +67,7 @@
 
   List<Point> get points => _points;
 
-  set points(List<Point> points) {
+  void set points(List<Point> points) {
     _points = points;
     _pointAges = <double>[];
     for (int i = 0; i < _points.length; i++) {
diff --git a/packages/flutter_sprites/lib/src/label.dart b/packages/flutter_sprites/lib/src/label.dart
index 09bfa55..0318cdc 100644
--- a/packages/flutter_sprites/lib/src/label.dart
+++ b/packages/flutter_sprites/lib/src/label.dart
@@ -15,7 +15,7 @@
   /// The text being drawn by the label.
   String get text => _text;
 
-  set text(String text) {
+  void set text(String text) {
     _text = text;
     _painter = null;
   }
@@ -25,7 +25,7 @@
   /// The style to draw the text in.
   TextStyle get textStyle => _textStyle;
 
-  set textStyle(TextStyle textStyle) {
+  void set textStyle(TextStyle textStyle) {
     _textStyle = textStyle;
     _painter = null;
   }
diff --git a/packages/flutter_sprites/lib/src/node.dart b/packages/flutter_sprites/lib/src/node.dart
index 38052e1..131e05c 100644
--- a/packages/flutter_sprites/lib/src/node.dart
+++ b/packages/flutter_sprites/lib/src/node.dart
@@ -85,7 +85,7 @@
     return _constraints;
   }
 
-  set constraints(List<Constraint> constraints) {
+  void set constraints(List<Constraint> constraints) {
     _constraints = constraints;
     if (_spriteBox != null) _spriteBox._constrainedNodes = null;
   }
@@ -803,7 +803,7 @@
   ///     );
   PhysicsBody get physicsBody => _physicsBody;
 
-  set physicsBody(PhysicsBody physicsBody) {
+  void set physicsBody(PhysicsBody physicsBody) {
     if (parent != null) {
       assert(parent is PhysicsWorld);
 
diff --git a/packages/flutter_sprites/lib/src/node3d.dart b/packages/flutter_sprites/lib/src/node3d.dart
index 40fb629..1424a21 100644
--- a/packages/flutter_sprites/lib/src/node3d.dart
+++ b/packages/flutter_sprites/lib/src/node3d.dart
@@ -13,7 +13,7 @@
   /// The node's rotation around the x axis in degrees.
   double get rotationX => _rotationX;
 
-  set rotationX(double rotationX) {
+  void set rotationX(double rotationX) {
     _rotationX = rotationX;
     invalidateTransformMatrix();
   }
@@ -23,7 +23,7 @@
   /// The node's rotation around the y axis in degrees.
   double get rotationY => _rotationY;
 
-  set rotationY(double rotationY) {
+  void set rotationY(double rotationY) {
     _rotationY = rotationY;
     invalidateTransformMatrix();
   }
@@ -33,7 +33,7 @@
   /// The projection depth. Default value is 500.0.
   double get projectionDepth => _projectionDepth;
 
-  set projectionDepth(double projectionDepth) {
+  void set projectionDepth(double projectionDepth) {
     _projectionDepth = projectionDepth;
     invalidateTransformMatrix();
   }
diff --git a/packages/flutter_sprites/lib/src/physics_body.dart b/packages/flutter_sprites/lib/src/physics_body.dart
index 9afed57..f29636e 100644
--- a/packages/flutter_sprites/lib/src/physics_body.dart
+++ b/packages/flutter_sprites/lib/src/physics_body.dart
@@ -91,7 +91,7 @@
   ///     myBody.density = 0.5;
   double get density => _density;
 
-  set density(double density) {
+  void set density(double density) {
     _density = density;
 
     if (_body == null)
@@ -109,7 +109,7 @@
   ///     myBody.friction = 0.4;
   double get friction => _friction;
 
-  set friction(double friction) {
+  void set friction(double friction) {
     _friction = friction;
 
     if (_body == null)
@@ -127,7 +127,7 @@
   /// the range of 0.0 to 1.0.
   ///
   ///     myBody.restitution = 0.5;
-  set restitution(double restitution) {
+  void set restitution(double restitution) {
     _restitution = restitution;
 
     if (_body == null)
@@ -146,7 +146,7 @@
   ///     myBody.isSensor = true;
   bool get isSensor => _isSensor;
 
-  set isSensor(bool isSensor) {
+  void set isSensor(bool isSensor) {
     _isSensor = isSensor;
 
     if (_body == null)
@@ -171,7 +171,7 @@
     }
   }
 
-  set linearVelocity(Offset linearVelocity) {
+  void set linearVelocity(Offset linearVelocity) {
     _linearVelocity = linearVelocity;
 
     if (_body != null) {
@@ -195,7 +195,7 @@
       return _body.angularVelocity;
   }
 
-  set angularVelocity(double angularVelocity) {
+  void set angularVelocity(double angularVelocity) {
     _angularVelocity = angularVelocity;
 
     if (_body != null) {
@@ -217,7 +217,7 @@
   ///     myBody.angularDampening = 0.1;
   double get angularDampening => _angularDampening;
 
-  set angularDampening(double angularDampening) {
+  void set angularDampening(double angularDampening) {
     _angularDampening = angularDampening;
 
     if (_body != null)
@@ -231,7 +231,7 @@
   ///     myBody.allowSleep = false;
   bool get allowSleep => _allowSleep;
 
-  set allowSleep(bool allowSleep) {
+  void set allowSleep(bool allowSleep) {
     _allowSleep = allowSleep;
 
     if (_body != null)
@@ -250,7 +250,7 @@
       return _awake;
   }
 
-  set awake(bool awake) {
+  void set awake(bool awake) {
     _awake = awake;
 
     if (_body != null)
@@ -264,7 +264,7 @@
   ///     myBody.fixedRotation = true;
   bool get fixedRotation => _fixedRotation;
 
-  set fixedRotation(bool fixedRotation) {
+  void set fixedRotation(bool fixedRotation) {
     _fixedRotation = fixedRotation;
 
     if (_body != null)
@@ -280,7 +280,7 @@
   /// if neccessary.
   ///
   ///     myBody.bullet = true;
-  set bullet(bool bullet) {
+  void set bullet(bool bullet) {
     _bullet = bullet;
 
     if (_body != null) {
@@ -301,7 +301,7 @@
       return _active;
   }
 
-  set active(bool active) {
+  void set active(bool active) {
     _active = active;
 
     if (_body != null)
@@ -321,7 +321,7 @@
     return _collisionCategory;
   }
 
-  set collisionCategory(Object collisionCategory) {
+  void set collisionCategory(Object collisionCategory) {
     _collisionCategory = collisionCategory;
     _updateFilter();
   }
@@ -334,7 +334,7 @@
   ///     myBody.collisionMask = ["Air", "Ground"];
   List<Object> get collisionMask => _collisionMask;
 
-  set collisionMask(List<Object> collisionMask) {
+  void set collisionMask(List<Object> collisionMask) {
     _collisionMask = collisionMask;
     _updateFilter();
   }
diff --git a/packages/flutter_sprites/lib/src/physics_group.dart b/packages/flutter_sprites/lib/src/physics_group.dart
index a78b0d5e..36cefa5 100644
--- a/packages/flutter_sprites/lib/src/physics_group.dart
+++ b/packages/flutter_sprites/lib/src/physics_group.dart
@@ -9,37 +9,37 @@
 ///     group.addChild(myNode);
 class PhysicsGroup extends Node {
 
-  set scaleX(double scaleX) {
+  void set scaleX(double scaleX) {
     assert(false);
   }
 
-  set scaleY(double scaleX) {
+  void set scaleY(double scaleX) {
     assert(false);
   }
 
-  set skewX(double scaleX) {
+  void set skewX(double scaleX) {
     assert(false);
   }
 
-  set skewY(double scaleX) {
+  void set skewY(double scaleX) {
     assert(false);
   }
 
-  set physicsBody(PhysicsBody body) {
+  void set physicsBody(PhysicsBody body) {
     assert(false);
   }
 
-  set position(Point position) {
+  void set position(Point position) {
     super.position = position;
     _invalidatePhysicsBodies(this);
   }
 
-  set rotation(double rotation) {
+  void set rotation(double rotation) {
     super.rotation = rotation;
     _invalidatePhysicsBodies(this);
   }
 
-  set scale(double scale) {
+  void set scale(double scale) {
     super.scale = scale;
     _invalidatePhysicsBodies(this);
   }
diff --git a/packages/flutter_sprites/lib/src/physics_joint.dart b/packages/flutter_sprites/lib/src/physics_joint.dart
index d5a0eef..f409f4d 100644
--- a/packages/flutter_sprites/lib/src/physics_joint.dart
+++ b/packages/flutter_sprites/lib/src/physics_joint.dart
@@ -147,7 +147,7 @@
   /// useful you also need to set [motorSpeed] and [maxMotorTorque].
   bool get enableMotor => _enableMotor;
 
-  set enableMotor(bool enableMotor) {
+  void set enableMotor(bool enableMotor) {
     _enableMotor = enableMotor;
     if (_joint != null) {
       box2d.RevoluteJoint revoluteJoint = _joint;
@@ -161,7 +161,7 @@
   /// set to true and [maxMotorTorque] is set to a non zero value.
   double get motorSpeed => _motorSpeed;
 
-  set motorSpeed(double motorSpeed) {
+  void set motorSpeed(double motorSpeed) {
     _motorSpeed = motorSpeed;
     if (_joint != null) {
       box2d.RevoluteJoint revoluteJoint = _joint;
@@ -175,7 +175,7 @@
 
   /// Sets the motor torque of this joint, will only work if [enableMotor] is
   /// set to true and [motorSpeed] is set to a non zero value.
-  set maxMotorTorque(double maxMotorTorque) {
+  void set maxMotorTorque(double maxMotorTorque) {
     _maxMotorTorque = maxMotorTorque;
     if (_joint != null) {
       box2d.RevoluteJoint revoluteJoint = _joint;
@@ -252,7 +252,7 @@
   /// [maxMotorForce].
   bool get enableMotor => _enableMotor;
 
-  set enableMotor(bool enableMotor) {
+  void set enableMotor(bool enableMotor) {
     _enableMotor = enableMotor;
     if (_joint != null) {
       box2d.PrismaticJoint prismaticJoint = _joint;
@@ -266,7 +266,7 @@
   /// set to true and [maxMotorForce] is set to a non zero value.
   double get motorSpeed => _motorSpeed;
 
-  set motorSpeed(double motorSpeed) {
+  void set motorSpeed(double motorSpeed) {
     _motorSpeed = motorSpeed;
     if (_joint != null) {
       box2d.PrismaticJoint prismaticJoint = _joint;
@@ -280,7 +280,7 @@
   /// set to true and [motorSpeed] is set to a non zero value.
   double get maxMotorForce => _maxMotorForce;
 
-  set maxMotorForce(double maxMotorForce) {
+  void set maxMotorForce(double maxMotorForce) {
     _maxMotorForce = maxMotorForce;
     if (_joint != null) {
       box2d.PrismaticJoint prismaticJoint = _joint;
diff --git a/packages/flutter_sprites/lib/src/physics_world.dart b/packages/flutter_sprites/lib/src/physics_world.dart
index 561ca08..8ab8e1a 100644
--- a/packages/flutter_sprites/lib/src/physics_world.dart
+++ b/packages/flutter_sprites/lib/src/physics_world.dart
@@ -74,7 +74,7 @@
     return new Offset(g.x, g.y);
   }
 
-  set gravity(Offset gravity) {
+  void set gravity(Offset gravity) {
     // Convert from points/s^2 to m/s^2
     b2World.setGravity(new Vector2(gravity.dx / b2WorldToNodeConversionFactor,
       gravity.dy / b2WorldToNodeConversionFactor));
@@ -83,14 +83,14 @@
   /// If set to true, objects can fall asleep if the haven't moved in a while.
   bool get allowSleep => b2World.isAllowSleep();
 
-  set allowSleep(bool allowSleep) {
+  void set allowSleep(bool allowSleep) {
     b2World.setAllowSleep(allowSleep);
   }
 
   /// True if sub stepping should be used in the simulation.
   bool get subStepping => b2World.isSubStepping();
 
-  set subStepping(bool subStepping) {
+  void set subStepping(bool subStepping) {
     b2World.setSubStepping(subStepping);
   }
 
diff --git a/packages/flutter_sprites/lib/src/sound.dart b/packages/flutter_sprites/lib/src/sound.dart
index 76395b0..6be942d 100644
--- a/packages/flutter_sprites/lib/src/sound.dart
+++ b/packages/flutter_sprites/lib/src/sound.dart
@@ -137,11 +137,8 @@
 class SoundTrackPlayer {
   Set<SoundTrack> _soundTracks = new HashSet<SoundTrack>();
 
-  static sharedInstance() {
-    if (_sharedSoundTrackPlayer == null) {
-      _sharedSoundTrackPlayer = new SoundTrackPlayer();
-    }
-    return _sharedSoundTrackPlayer;
+  static SoundTrackPlayer sharedInstance() {
+    return _sharedSoundTrackPlayer ??= new SoundTrackPlayer();
   }
 
   SoundTrackPlayer() {
diff --git a/packages/flutter_sprites/lib/src/sprite_box.dart b/packages/flutter_sprites/lib/src/sprite_box.dart
index 20dbc49..25685a6 100644
--- a/packages/flutter_sprites/lib/src/sprite_box.dart
+++ b/packages/flutter_sprites/lib/src/sprite_box.dart
@@ -38,7 +38,8 @@
       || value.size.height > 0);
 
     // Remove sprite box references
-    if (_rootNode != null) _removeSpriteBoxReference(_rootNode);
+    if (_rootNode != null)
+      _removeSpriteBoxReference(_rootNode);
 
     // Update the value
     _rootNode = value;
@@ -374,7 +375,7 @@
     double delta = (timeStamp - _lastTimeStamp).inMicroseconds.toDouble() / Duration.MICROSECONDS_PER_SECOND;
     _lastTimeStamp = timeStamp;
 
-    _frameRate = 1.0/delta;
+    _frameRate = 1.0 / delta;
 
     if (_initialized) {
       _callConstraintsPreUpdate(delta);
@@ -497,7 +498,7 @@
     return nodes;
   }
 
-  _addNodesAtPosition(Node node, Point position, List<Node> list) {
+  void _addNodesAtPosition(Node node, Point position, List<Node> list) {
     // Visit children first
     for (Node child in node.children) {
       _addNodesAtPosition(child, position, list);
diff --git a/packages/flutter_sprites/lib/src/textured_line.dart b/packages/flutter_sprites/lib/src/textured_line.dart
index 2cbe95f..11c70f0 100644
--- a/packages/flutter_sprites/lib/src/textured_line.dart
+++ b/packages/flutter_sprites/lib/src/textured_line.dart
@@ -21,7 +21,7 @@
 
   List<Point> get points => _points;
 
-  set points(List<Point> points) {
+  void set points(List<Point> points) {
     _points = points;
     _calculatedTextureStops = null;
   }
@@ -32,7 +32,7 @@
 
   Texture get texture => _texture;
 
-  set texture(Texture texture) {
+  void set texture(Texture texture) {
     _texture = texture;
     if (texture == null) {
       _cachedPaint = new Paint();
@@ -68,9 +68,9 @@
 
   double _textureLoopLength;
 
-  get textureLoopLength => textureLoopLength;
+  double get textureLoopLength => textureLoopLength;
 
-  set textureLoopLength(double textureLoopLength) {
+  void set textureLoopLength(double textureLoopLength) {
     _textureLoopLength = textureLoopLength;
     _calculatedTextureStops = null;
   }
diff --git a/packages/flutter_tools/bin/flutter_tools.dart b/packages/flutter_tools/bin/flutter_tools.dart
index 482239c..762e6a5 100644
--- a/packages/flutter_tools/bin/flutter_tools.dart
+++ b/packages/flutter_tools/bin/flutter_tools.dart
@@ -4,4 +4,6 @@
 
 import 'package:flutter_tools/executable.dart' as executable;
 
-main(List<String> args) => executable.main(args);
+void main(List<String> args) {
+  executable.main(args);
+}
diff --git a/packages/flutter_tools/lib/src/android/adb.dart b/packages/flutter_tools/lib/src/android/adb.dart
index 0320b3c..e8b648e 100644
--- a/packages/flutter_tools/lib/src/android/adb.dart
+++ b/packages/flutter_tools/lib/src/android/adb.dart
@@ -204,7 +204,7 @@
   /// Device model; can be null. `XT1045`, `Nexus_7`
   String get modelID => _info['model'];
 
-  set modelID(String value) {
+  void set modelID(String value) {
     _info['model'] = value;
   }
 
diff --git a/packages/flutter_tools/lib/src/commands/analyze.dart b/packages/flutter_tools/lib/src/commands/analyze.dart
index 220c639..c6afb1b 100644
--- a/packages/flutter_tools/lib/src/commands/analyze.dart
+++ b/packages/flutter_tools/lib/src/commands/analyze.dart
@@ -288,6 +288,7 @@
     todo: ignore
 linter:
   rules:
+    - always_declare_return_types
     # we'll turn on avoid_as as soon as it doesn't complain about "as dynamic"
     # - avoid_as
     - camel_case_types
diff --git a/packages/flutter_tools/test/adb_test.dart b/packages/flutter_tools/test/adb_test.dart
index f8b505c..168085b 100644
--- a/packages/flutter_tools/test/adb_test.dart
+++ b/packages/flutter_tools/test/adb_test.dart
@@ -5,9 +5,7 @@
 import 'package:flutter_tools/src/android/adb.dart';
 import 'package:test/test.dart';
 
-main() => defineTests();
-
-defineTests() {
+void main() {
   Adb adb = new Adb('adb');
 
   // We only test the [Adb] class is we're able to locate the adb binary.
diff --git a/packages/flutter_tools/test/analyze_test.dart b/packages/flutter_tools/test/analyze_test.dart
index 9ff1be2..bddf95f 100644
--- a/packages/flutter_tools/test/analyze_test.dart
+++ b/packages/flutter_tools/test/analyze_test.dart
@@ -14,9 +14,7 @@
 
 import 'src/context.dart';
 
-main() => defineTests();
-
-defineTests() {
+void main() {
   AnalysisServer server;
   Directory tempDir;
 
diff --git a/packages/flutter_tools/test/android_device_test.dart b/packages/flutter_tools/test/android_device_test.dart
index 2ad4701..be14072 100644
--- a/packages/flutter_tools/test/android_device_test.dart
+++ b/packages/flutter_tools/test/android_device_test.dart
@@ -7,9 +7,7 @@
 
 import 'src/context.dart';
 
-main() => defineTests();
-
-defineTests() {
+void main() {
   group('android_device', () {
     testUsingContext('stores the requested id', () {
       String deviceId = '1234';
diff --git a/packages/flutter_tools/test/base_utils_test.dart b/packages/flutter_tools/test/base_utils_test.dart
index 053fdd4..ad5a47d 100644
--- a/packages/flutter_tools/test/base_utils_test.dart
+++ b/packages/flutter_tools/test/base_utils_test.dart
@@ -7,9 +7,7 @@
 import 'package:flutter_tools/src/base/utils.dart';
 import 'package:test/test.dart';
 
-main() => defineTests();
-
-defineTests() {
+void main() {
   group('ItemListNotifier', () {
     test('sends notifications', () async {
       ItemListNotifier<String> list = new ItemListNotifier<String>();
diff --git a/packages/flutter_tools/test/context_test.dart b/packages/flutter_tools/test/context_test.dart
index 1de5840..8141909 100644
--- a/packages/flutter_tools/test/context_test.dart
+++ b/packages/flutter_tools/test/context_test.dart
@@ -7,9 +7,7 @@
 import 'package:flutter_tools/src/globals.dart';
 import 'package:test/test.dart';
 
-main() => defineTests();
-
-defineTests() {
+void main() {
   group('DeviceManager', () {
     test('error', () async {
       AppContext context = new AppContext();
diff --git a/packages/flutter_tools/test/create_test.dart b/packages/flutter_tools/test/create_test.dart
index 84e337d..703f8c6 100644
--- a/packages/flutter_tools/test/create_test.dart
+++ b/packages/flutter_tools/test/create_test.dart
@@ -13,9 +13,7 @@
 
 import 'src/context.dart';
 
-main() => defineTests();
-
-defineTests() {
+void main() {
   group('create', () {
     Directory temp;
 
diff --git a/packages/flutter_tools/test/daemon_test.dart b/packages/flutter_tools/test/daemon_test.dart
index 9f986fc..fa34531 100644
--- a/packages/flutter_tools/test/daemon_test.dart
+++ b/packages/flutter_tools/test/daemon_test.dart
@@ -17,9 +17,7 @@
 import 'src/context.dart';
 import 'src/mocks.dart';
 
-main() => defineTests();
-
-defineTests() {
+void main() {
   Daemon daemon;
   AppContext appContext;
   NotifyingLogger notifyingLogger;
diff --git a/packages/flutter_tools/test/device_test.dart b/packages/flutter_tools/test/device_test.dart
index 3ea8f09..2bb2fb7 100644
--- a/packages/flutter_tools/test/device_test.dart
+++ b/packages/flutter_tools/test/device_test.dart
@@ -7,9 +7,7 @@
 
 import 'src/context.dart';
 
-main() => defineTests();
-
-defineTests() {
+void main() {
   group('DeviceManager', () {
     testUsingContext('getDevices', () async {
       // Test that DeviceManager.getDevices() doesn't throw.
diff --git a/packages/flutter_tools/test/devices.test.dart b/packages/flutter_tools/test/devices.test.dart
index 767d4ce..49660c7 100644
--- a/packages/flutter_tools/test/devices.test.dart
+++ b/packages/flutter_tools/test/devices.test.dart
@@ -10,9 +10,7 @@
 import 'src/common.dart';
 import 'src/context.dart';
 
-main() => defineTests();
-
-defineTests() {
+void main() {
   group('devices', () {
     testUsingContext('returns 0 when called', () {
       DevicesCommand command = new DevicesCommand();
diff --git a/packages/flutter_tools/test/drive_test.dart b/packages/flutter_tools/test/drive_test.dart
index f95f76c..62c14f6 100644
--- a/packages/flutter_tools/test/drive_test.dart
+++ b/packages/flutter_tools/test/drive_test.dart
@@ -20,9 +20,7 @@
 import 'src/context.dart';
 import 'src/mocks.dart';
 
-main() => defineTests();
-
-defineTests() {
+void main() {
   group('drive', () {
     DriveCommand command;
     Device mockDevice;
@@ -182,7 +180,7 @@
     });
 
     group('findTargetDevice on iOS', () {
-      setOs() {
+      void setOs() {
         when(os.isMacOS).thenReturn(true);
         when(os.isLinux).thenReturn(false);
       }
@@ -222,7 +220,7 @@
     });
 
     group('findTargetDevice on Linux', () {
-      setOs() {
+      void setOs() {
         when(os.isMacOS).thenReturn(false);
         when(os.isLinux).thenReturn(true);
       }
diff --git a/packages/flutter_tools/test/install_test.dart b/packages/flutter_tools/test/install_test.dart
index fc7d2fd..aaa6186 100644
--- a/packages/flutter_tools/test/install_test.dart
+++ b/packages/flutter_tools/test/install_test.dart
@@ -10,9 +10,7 @@
 import 'src/context.dart';
 import 'src/mocks.dart';
 
-main() => defineTests();
-
-defineTests() {
+void main() {
   group('install', () {
     testUsingContext('returns 0 when Android is connected and ready for an install', () {
       InstallCommand command = new InstallCommand();
diff --git a/packages/flutter_tools/test/listen_test.dart b/packages/flutter_tools/test/listen_test.dart
index 701dc24..56bac43 100644
--- a/packages/flutter_tools/test/listen_test.dart
+++ b/packages/flutter_tools/test/listen_test.dart
@@ -9,9 +9,7 @@
 import 'src/context.dart';
 import 'src/mocks.dart';
 
-main() => defineTests();
-
-defineTests() {
+void main() {
   group('listen', () {
     testUsingContext('returns 1 when no device is connected', () {
       ListenCommand command = new ListenCommand(singleRun: true);
diff --git a/packages/flutter_tools/test/logs_test.dart b/packages/flutter_tools/test/logs_test.dart
index ba5bdc9..ef99320 100644
--- a/packages/flutter_tools/test/logs_test.dart
+++ b/packages/flutter_tools/test/logs_test.dart
@@ -9,9 +9,7 @@
 import 'src/context.dart';
 import 'src/mocks.dart';
 
-main() => defineTests();
-
-defineTests() {
+void main() {
   group('logs', () {
     testUsingContext('fail with a bad device id', () {
       LogsCommand command = new LogsCommand();
diff --git a/packages/flutter_tools/test/os_utils_test.dart b/packages/flutter_tools/test/os_utils_test.dart
index 9dacd2f..87a7c28 100644
--- a/packages/flutter_tools/test/os_utils_test.dart
+++ b/packages/flutter_tools/test/os_utils_test.dart
@@ -8,9 +8,7 @@
 import 'package:path/path.dart' as path;
 import 'package:test/test.dart';
 
-main() => defineTests();
-
-defineTests() {
+void main() {
   group('OperatingSystemUtils', () {
     Directory temp;
 
diff --git a/packages/flutter_tools/test/run_test.dart b/packages/flutter_tools/test/run_test.dart
index 8c07516..4f7c7e9 100644
--- a/packages/flutter_tools/test/run_test.dart
+++ b/packages/flutter_tools/test/run_test.dart
@@ -9,9 +9,7 @@
 import 'src/context.dart';
 import 'src/mocks.dart';
 
-main() => defineTests();
-
-defineTests() {
+void main() {
   group('run', () {
     testUsingContext('fails when target not found', () {
       RunCommand command = new RunCommand();
diff --git a/packages/flutter_tools/test/service_protocol_test.dart b/packages/flutter_tools/test/service_protocol_test.dart
index 7c62e57..3498b5c 100644
--- a/packages/flutter_tools/test/service_protocol_test.dart
+++ b/packages/flutter_tools/test/service_protocol_test.dart
@@ -9,9 +9,7 @@
 
 import 'src/mocks.dart';
 
-main() => defineTests();
-
-defineTests() {
+void main() {
   group('service_protocol', () {
     test('Discovery Heartbeat', () async {
       MockDeviceLogReader logReader = new MockDeviceLogReader();
diff --git a/packages/flutter_tools/test/stop_test.dart b/packages/flutter_tools/test/stop_test.dart
index 112a9fc..d3c5f31 100644
--- a/packages/flutter_tools/test/stop_test.dart
+++ b/packages/flutter_tools/test/stop_test.dart
@@ -12,9 +12,7 @@
 import 'src/context.dart';
 import 'src/mocks.dart';
 
-main() => defineTests();
-
-defineTests() {
+void main() {
   group('stop', () {
     testUsingContext('returns 0 when Android is connected and ready to be stopped', () {
       StopCommand command = new StopCommand();
diff --git a/packages/flutter_tools/test/trace_test.dart b/packages/flutter_tools/test/trace_test.dart
index 5fc2cd7..e987067 100644
--- a/packages/flutter_tools/test/trace_test.dart
+++ b/packages/flutter_tools/test/trace_test.dart
@@ -9,9 +9,7 @@
 import 'src/context.dart';
 import 'src/mocks.dart';
 
-main() => defineTests();
-
-defineTests() {
+void main() {
   group('trace', () {
     testUsingContext('returns 1 when no Android device is connected', () {
       TraceCommand command = new TraceCommand();
diff --git a/packages/flx/test/bundle_test.dart b/packages/flx/test/bundle_test.dart
index a54ccfe..521502a 100644
--- a/packages/flx/test/bundle_test.dart
+++ b/packages/flx/test/bundle_test.dart
@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'dart:convert' hide BASE64;
 import 'dart:io';
 import 'dart:typed_data';
@@ -7,7 +8,7 @@
 import 'package:flx/signing.dart';
 import 'package:test/test.dart';
 
-main() async {
+Future main() async {
   // The following constant was generated via the openssl shell commands:
   // openssl ecparam -genkey -name prime256v1 -out privatekey.pem
   // openssl ec -in privatekey.pem -outform DER | base64
diff --git a/packages/flx/test/signing_test.dart b/packages/flx/test/signing_test.dart
index 46e746e..585ca79 100644
--- a/packages/flx/test/signing_test.dart
+++ b/packages/flx/test/signing_test.dart
@@ -8,7 +8,7 @@
 import 'package:flx/signing.dart';
 import 'package:test/test.dart';
 
-main() async {
+Future main() async {
   // The following constant was generated via the openssl shell commands:
   // openssl ecparam -genkey -name prime256v1 -out privatekey.pem
   // openssl ec -in privatekey.pem -outform DER | base64