apply the upcoming rule unnecessary_this (#8838)

dev/devicelab/test/adb_test.dart

@@ -130,9 +130,9 @@ class CommandArgs {
       return false;
 
     final CommandArgs otherCmd = other;
-    return otherCmd.command == this.command &&
-      const ListEquality<String>().equals(otherCmd.arguments, this.arguments) &&
-      const MapEquality<String, String>().equals(otherCmd.environment, this.environment);
+    return otherCmd.command == command &&
+      const ListEquality<String>().equals(otherCmd.arguments, arguments) &&
+      const MapEquality<String, String>().equals(otherCmd.environment, environment);
   }
 
   @override

examples/flutter_gallery/lib/demo/calculator/home.dart

@@ -231,7 +231,7 @@ class KeyRow extends StatelessWidget {
     return new Expanded(
       child: new Row(
         mainAxisAlignment: MainAxisAlignment.center,
-        children: this.keys
+        children: keys
       )
     );
   }
@@ -248,10 +248,10 @@ class CalcKey extends StatelessWidget {
     final Orientation orientation = MediaQuery.of(context).orientation;
     return new Expanded(
       child: new InkResponse(
-        onTap: this.onTap,
+        onTap: onTap,
         child: new Center(
           child: new Text(
-            this.text,
+            text,
             style: new TextStyle(
               fontSize: (orientation == Orientation.portrait) ? 32.0 : 24.0
             )

examples/flutter_gallery/lib/demo/colors_demo.dart

@@ -14,7 +14,7 @@ class ColorSwatch {
   final Map<int, Color> accentColors;
   final int threshold; // titles for indices > threshold are white, otherwise black
 
-  bool get isValid => this.name != null && this.colors != null && threshold != null;
+  bool get isValid => name != null && colors != null && threshold != null;
 }
 
 final List<ColorSwatch> colorSwatches = <ColorSwatch>[

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

@@ -592,9 +592,9 @@ abstract class CompoundAnimation<T> extends Animation<T>
 
   AnimationStatus _lastStatus;
   void _maybeNotifyStatusListeners(AnimationStatus _) {
-    if (this.status != _lastStatus) {
-      _lastStatus = this.status;
-      notifyStatusListeners(this.status);
+    if (status != _lastStatus) {
+      _lastStatus = status;
+      notifyStatusListeners(status);
     }
   }
 

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

@@ -53,8 +53,8 @@ class BottomNavigationBarItem {
     @required this.title,
     this.backgroundColor
   }) {
-    assert(this.icon != null);
-    assert(this.title != null);
+    assert(icon != null);
+    assert(title != null);
   }
 
   /// The icon of the item.
@@ -492,9 +492,9 @@ class _Circle {
     this.color,
     @required TickerProvider vsync,
   }) {
-    assert(this.state != null);
-    assert(this.index != null);
-    assert(this.color != null);
+    assert(state != null);
+    assert(index != null);
+    assert(color != null);
 
     controller = new AnimationController(
       duration: kThemeAnimationDuration,

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

@@ -28,9 +28,9 @@ class ExpandIcon extends StatefulWidget {
     @required this.onPressed,
     this.padding: const EdgeInsets.all(8.0)
   }) : super(key: key) {
-    assert(this.isExpanded != null);
-    assert(this.size != null);
-    assert(this.padding != null);
+    assert(isExpanded != null);
+    assert(size != null);
+    assert(padding != null);
   }
 
   /// Whether the icon is in an expanded state.

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

@@ -44,9 +44,9 @@ class ExpansionPanel {
     @required this.body,
     this.isExpanded: false
   }) {
-    assert(this.headerBuilder != null);
-    assert(this.body != null);
-    assert(this.isExpanded != null);
+    assert(headerBuilder != null);
+    assert(body != null);
+    assert(isExpanded != null);
   }
 
   /// The widget builder that builds the expansion panels' header.
@@ -79,8 +79,8 @@ class ExpansionPanelList extends StatelessWidget {
     this.expansionCallback,
     this.animationDuration: kThemeAnimationDuration
   }) : super(key: key) {
-    assert(this.children != null);
-    assert(this.animationDuration != null);
+    assert(children != null);
+    assert(animationDuration != null);
   }
 
   /// The children of the expansion panel list. They are layed in a similar

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

@@ -81,9 +81,9 @@ class Step {
     this.state: StepState.indexed,
     this.isActive: false,
   }) {
-    assert(this.title != null);
-    assert(this.content != null);
-    assert(this.state != null);
+    assert(title != null);
+    assert(content != null);
+    assert(state != null);
   }
 
   /// The title of the step that typically describes it.
@@ -138,10 +138,10 @@ class Stepper extends StatefulWidget {
     this.onStepContinue,
     this.onStepCancel,
   }) : super(key: key) {
-    assert(this.steps != null);
-    assert(this.type != null);
-    assert(this.currentStep != null);
-    assert(0 <= currentStep && currentStep < this.steps.length);
+    assert(steps != null);
+    assert(type != null);
+    assert(currentStep != null);
+    assert(0 <= currentStep && currentStep < steps.length);
   }
 
   /// The steps of the stepper whose titles, subtitles, icons always get shown.

packages/flutter/lib/src/scheduler/ticker.dart

@@ -132,7 +132,7 @@ class Ticker {
         throw new FlutterError(
           'A ticker was started twice.\n'
           'A ticker that is already active cannot be started again without first stopping it.\n'
-          'The affected ticker was: ${ this.toString(debugIncludeStack: true) }'
+          'The affected ticker was: ${ toString(debugIncludeStack: true) }'
         );
       }
       return true;

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

@@ -53,9 +53,9 @@ class AnimatedCrossFade extends StatefulWidget {
     @required this.crossFadeState,
     @required this.duration
   }) : super(key: key) {
-    assert(this.firstCurve != null);
-    assert(this.secondCurve != null);
-    assert(this.sizeCurve != null);
+    assert(firstCurve != null);
+    assert(secondCurve != null);
+    assert(sizeCurve != null);
   }
 
   /// The child that is visible when [crossFadeState] is [showFirst]. It fades

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

@@ -26,10 +26,10 @@ abstract class ScrollView extends StatelessWidget {
     this.shrinkWrap: false,
   }) : primary = primary ?? controller == null && scrollDirection == Axis.vertical,
        super(key: key) {
-    assert(this.reverse != null);
-    assert(this.shrinkWrap != null);
+    assert(reverse != null);
+    assert(shrinkWrap != null);
     assert(this.primary != null);
-    assert(this.controller == null || !this.primary,
+    assert(controller == null || !this.primary,
            'Primary ScrollViews obtain their ScrollController via inheritance from a PrimaryScrollController widget. '
            'You cannot both set primary to true and pass an explicit controller.'
     );

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

@@ -49,9 +49,9 @@ class SingleChildScrollView extends StatelessWidget {
     this.child,
   }) : primary = primary ?? controller == null && scrollDirection == Axis.vertical,
        super(key: key) {
-    assert(this.scrollDirection != null);
+    assert(scrollDirection != null);
     assert(this.primary != null);
-    assert(this.controller == null || !this.primary,
+    assert(controller == null || !this.primary,
        'Primary ScrollViews obtain their ScrollController via inheritance from a PrimaryScrollController widget. '
        'You cannot both set primary to true and pass an explicit controller.'
     );

packages/flutter/test/widgets/dismissable_test.dart

@@ -122,7 +122,7 @@ class Test1215DismissableWidget extends StatelessWidget {
       key: new ObjectKey(text),
       child: new AspectRatio(
         aspectRatio: 1.0,
-        child: new Text(this.text),
+        child: new Text(text),
       ),
     );
   }

packages/flutter/test/widgets/independent_widget_layout_test.dart

@@ -73,12 +73,12 @@ class TriggerableState extends State<TriggerableWidget> {
   @override
   void initState() {
     super.initState();
-    config.trigger.callback = this.fire;
+    config.trigger.callback = fire;
   }
 
   @override
   void didUpdateConfig(TriggerableWidget oldConfig) {
-    config.trigger.callback = this.fire;
+    config.trigger.callback = fire;
   }
 
   int _count = 0;

packages/flutter_tools/lib/src/asset.dart

@@ -156,11 +156,10 @@ class AssetBundle {
 }
 
 class _Asset {
-  _Asset({ this.base, String assetEntry, this.relativePath, this.source }) {
-    this._assetEntry = assetEntry;
-  }
+  _Asset({ this.base, String assetEntry, this.relativePath, this.source })
+    : _assetEntry = assetEntry;
 
-  String _assetEntry;
+  final String _assetEntry;
 
   final String base;
 

packages/flutter_tools/lib/src/cache.dart

@@ -15,11 +15,9 @@ import 'globals.dart';
 /// A wrapper around the `bin/cache/` directory.
 class Cache {
   /// [rootOverride] is configurable for testing.
-  Cache({ Directory rootOverride }) {
-    this._rootOverride = rootOverride;
-  }
+  Cache({ Directory rootOverride }) : _rootOverride = rootOverride;
 
-  Directory _rootOverride;
+  final Directory _rootOverride;
 
   // Initialized by FlutterCommandRunner on startup.
   static String flutterRoot;

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

@@ -89,7 +89,7 @@ class DriveCommand extends RunCommandBase {
     if (testFile == null)
       throwToolExit(null);
 
-    this._device = await targetDeviceFinder();
+    _device = await targetDeviceFinder();
     if (device == null)
       throwToolExit(null);