Increase the strictness of our requiring explicit types (#7585)

...now that we have generic methods, their types need to be specified too.

.analysis_options

@@ -16,7 +16,8 @@ analyzer:
   language:
     enableStrictCallChecks: true
     enableSuperMixins: true
-  strong-mode: true
+  strong-mode:
+    implicit-dynamic: false
   errors:
     # allow overriding fields (if they use super, ideally...)
     strong_mode_invalid_field_override: ignore

.analysis_options_repo

@@ -17,7 +17,8 @@ analyzer:
   language:
     enableStrictCallChecks: true
     enableSuperMixins: true
-  strong-mode: true
+  strong-mode:
+    implicit-dynamic: false
   errors:
     # allow overriding fields (if they use super, ideally...)
     strong_mode_invalid_field_override: ignore

dev/devicelab/lib/framework/runner.dart

@@ -37,7 +37,7 @@ Future<Map<String, dynamic>> runTask(String taskName, { bool silent: false }) as
 
   bool runnerFinished = false;
 
-  runner.exitCode.then((_) {
+  runner.exitCode.whenComplete(() {
     runnerFinished = true;
   });
 

dev/devicelab/lib/framework/utils.dart

@@ -166,7 +166,7 @@ Future<Process> startProcess(String executable, List<String> arguments,
   ProcessInfo procInfo = new ProcessInfo(command, proc);
   _runningProcesses.add(procInfo);
 
-  proc.exitCode.then((_) {
+  proc.exitCode.whenComplete(() {
     _runningProcesses.remove(procInfo);
   });
 

examples/flutter_gallery/lib/demo/dialog_demo.dart

@@ -70,7 +70,7 @@ class DialogDemoState extends State<DialogDemo> {
       context: context,
       child: child
     )
-    .then((T value) { // The value passed to Navigator.pop() or null.
+    .then<Null>((T value) { // The value passed to Navigator.pop() or null.
       if (value != null) {
         _scaffoldKey.currentState.showSnackBar(new SnackBar(
           content: new Text('You selected: $value')
@@ -178,7 +178,7 @@ class DialogDemoState extends State<DialogDemo> {
                 context: context,
                 initialTime: _selectedTime
               )
-              .then((TimeOfDay value) {
+              .then<Null>((TimeOfDay value) {
                 if (value != null && value != _selectedTime) {
                   _selectedTime = value;
                   _scaffoldKey.currentState.showSnackBar(new SnackBar(

examples/flutter_gallery/lib/demo/full_screen_dialog_demo.dart

@@ -48,7 +48,7 @@ class DateTimeItem extends StatelessWidget {
                     firstDate: date.subtract(const Duration(days: 30)),
                     lastDate: date.add(const Duration(days: 30))
                   )
-                  .then((DateTime value) {
+                  .then<Null>((DateTime value) {
                     onChanged(new DateTime(value.year, value.month, value.day, time.hour, time.minute));
                   });
                 },
@@ -74,7 +74,7 @@ class DateTimeItem extends StatelessWidget {
                   context: context,
                   initialTime: time
                 )
-                .then((TimeOfDay value) {
+                .then<Null>((TimeOfDay value) {
                   onChanged(new DateTime(date.year, date.month, date.day, value.hour, value.minute));
                 });
               },
@@ -112,7 +112,7 @@ class FullScreenDialogDemoState extends State<FullScreenDialogDemo> {
     final ThemeData theme = Theme.of(context);
     final TextStyle dialogTextStyle = theme.textTheme.subhead.copyWith(color: theme.textTheme.caption.color);
 
-    showDialog(
+    showDialog<DismissDialogAction>(
       context: context,
       child: new AlertDialog(
         content: new Text(

examples/flutter_gallery/lib/demo/persistent_bottom_sheet_demo.dart

@@ -22,7 +22,6 @@ class _PersistentBottomSheetDemoState extends State<PersistentBottomSheetDemo> {
     _showBottomSheetCallback = _showBottomSheet;
   }
 
-
   void _showBottomSheet() {
     setState(() { // disable the button
       _showBottomSheetCallback = null;
@@ -45,15 +44,17 @@ class _PersistentBottomSheetDemoState extends State<PersistentBottomSheetDemo> {
         )
       );
     })
-    .closed.then((_) {
-      setState(() { // re-enable the button
-        _showBottomSheetCallback = _showBottomSheet;
-      });
+    .closed.whenComplete(() {
+      if (mounted) {
+        setState(() { // re-enable the button
+          _showBottomSheetCallback = _showBottomSheet;
+        });
+      }
     });
   }
 
   void _showMessage()  {
-    showDialog(
+    showDialog<Null>(
       context: context,
       child: new AlertDialog(
         content: new Text('You tapped the floating action button.'),

examples/flutter_gallery/lib/demo/tabs_fab_demo.dart

@@ -66,7 +66,7 @@ class _TabsFabDemoState extends State<TabsFabDemo> with SingleTickerProviderStat
   }
 
   void _showExplanatoryText() {
-    _scaffoldKey.currentState.showBottomSheet((BuildContext context) {
+    _scaffoldKey.currentState.showBottomSheet<Null>((BuildContext context) {
       return new Container(
         decoration: new BoxDecoration(
           border: new Border(top: new BorderSide(color: Theme.of(context).dividerColor))

examples/flutter_gallery/lib/gallery/demo.dart

@@ -110,10 +110,12 @@ class FullScreenCodeDialogState extends State<FullScreenCodeDialog> {
 
   @override
   void dependenciesChanged() {
-    getExampleCode(config.exampleCodeTag, DefaultAssetBundle.of(context)).then((String code) {
-      setState(() {
-        _exampleCode = code;
-      });
+    getExampleCode(config.exampleCodeTag, DefaultAssetBundle.of(context)).then<Null>((String code) {
+      if (mounted) {
+        setState(() {
+          _exampleCode = code;
+        });
+      }
     });
     super.dependenciesChanged();
   }

examples/flutter_gallery/test/example_code_parser_test.dart

@@ -46,7 +46,7 @@ class TestAssetBundle extends AssetBundle {
   }
 
   @override
-  Future<dynamic> loadStructuredData(String key, Future<dynamic> parser(String value)) async {
+  Future<dynamic> loadStructuredData<T>(String key, Future<T> parser(String value)) async {
     return parser(await loadString(key));
   }
 

examples/flutter_gallery/test_driver/transitions_perf_test.dart

@@ -167,7 +167,7 @@ void main() {
             if (!unsynchedDemoTitles.contains(demoTitle)) {
               await driver.tap(find.byTooltip('Back'));
             } else {
-              await driver.runUnsynchronized(() async {
+              await driver.runUnsynchronized<Future<Null>>(() async {
                 await new Future<Null>.delayed(kWaitBetweenActions);
                 await driver.tap(find.byTooltip('Back'));
               });

examples/layers/services/isolate.dart

@@ -137,12 +137,12 @@ class CalculationManager {
     // the root bundle (see https://github.com/flutter/flutter/issues/3294).
     // However, the loading process is asynchronous, so the UI will not block
     // while the file is loaded.
-    rootBundle.loadString('services/data.json').then((String data) {
+    rootBundle.loadString('services/data.json').then<Null>((String data) {
       if (isRunning) {
-        CalculationMessage message = new CalculationMessage(data, _receivePort.sendPort);
+        final CalculationMessage message = new CalculationMessage(data, _receivePort.sendPort);
         // Spawn an isolate to JSON-parse the file contents. The JSON parsing
         // is synchronous, so if done in the main isolate, the UI would block.
-        Isolate.spawn(_calculate, message).then((Isolate isolate) {
+        Isolate.spawn(_calculate, message).then<Null>((Isolate isolate) {
           if (!isRunning) {
             isolate.kill(priority: Isolate.IMMEDIATE);
           } else {

examples/layers/widgets/styled_text.dart

@@ -4,7 +4,7 @@
 
 import 'package:flutter/material.dart';
 
-typedef Widget TextTransformer(String name, String text);
+typedef Widget _TextTransformer(String name, String text);
 
 // From https://en.wikiquote.org/wiki/2001:_A_Space_Odyssey_(film)
 const String _kDialogText = '''
@@ -84,7 +84,7 @@ class _StyledTextDemoState extends State<StyledTextDemo> {
     _toText = toStyledText;
   }
 
-  TextTransformer _toText;
+  _TextTransformer _toText;
 
   void _handleTap() {
     setState(() {
@@ -95,7 +95,7 @@ class _StyledTextDemoState extends State<StyledTextDemo> {
   @override
   Widget build(BuildContext context) {
     List<Widget> lines = _kNameLines
-      .map((List<String> nameAndText) => Function.apply(_toText, nameAndText))
+      .map<Widget>((List<String> nameAndText) => _toText(nameAndText[0], nameAndText[1]))
       .toList();
 
     List<Widget> children = <Widget>[];

examples/stocks/lib/stock_data.dart

@@ -72,7 +72,7 @@ class StockDataFetcher {
   void _fetchNextChunk() {
     if (!actuallyFetchData)
       return;
-    http.get(_urlToFetch(_nextChunk++)).then((http.Response response) {
+    http.get(_urlToFetch(_nextChunk++)).then<Null>((http.Response response) {
       String json = response.body;
       if (json == null) {
         print("Failed to load stock data chunk ${_nextChunk - 1}");

examples/stocks/lib/stock_home.dart

@@ -105,7 +105,7 @@ class StockHomeState extends State<StockHome> {
         });
         break;
       case _StockMenuItem.refresh:
-        showDialog(
+        showDialog<Null>(
           context: context,
           child: new _NotImplementedDialog()
         );
@@ -267,7 +267,7 @@ class StockHomeState extends State<StockHome> {
         Navigator.pushNamed(context, '/stock/${stock.symbol}');
       },
       onShow: (Stock stock) {
-        _scaffoldKey.currentState.showBottomSheet((BuildContext context) => new StockSymbolBottomSheet(stock: stock));
+        _scaffoldKey.currentState.showBottomSheet<Null>((BuildContext context) => new StockSymbolBottomSheet(stock: stock));
       }
     );
   }

examples/stocks/lib/stock_settings.dart

@@ -65,7 +65,7 @@ class StockSettingsState extends State<StockSettings> {
         _handleOptimismChanged(false);
         break;
       case StockMode.pessimistic:
-        showDialog(
+        showDialog<bool>(
           context: context,
           child: new AlertDialog(
             title: new Text("Change mode?"),
@@ -85,7 +85,7 @@ class StockSettingsState extends State<StockSettings> {
               ),
             ]
           )
-        ).then(_handleOptimismChanged);
+        ).then<Null>(_handleOptimismChanged);
         break;
     }
   }

packages/flutter/lib/src/foundation/synchronous_future.dart

@@ -51,7 +51,7 @@ class SynchronousFuture<T> implements Future<T> {
     try {
       dynamic result = action();
       if (result is Future)
-        return result.then((_) => _value);
+        return result.then<T>((dynamic value) => _value);
       return this;
     } catch (e, stack) {
       return new Future<T>.error(e, stack);

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

@@ -515,7 +515,7 @@ class _DropdownButtonState<T> extends State<DropdownButton<T>> {
       elevation: config.elevation,
       theme: Theme.of(context, shadowThemeOnly: true),
       style: _textStyle,
-    )).then((_DropdownRouteResult<T> newValue) {
+    )).then<Null>((_DropdownRouteResult<T> newValue) {
       if (!mounted || newValue == null)
         return;
       if (config.onChanged != null)

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

@@ -535,7 +535,7 @@ class _PopupMenuButtonState<T> extends State<PopupMenuButton<T>> {
         0.0, 0.0
       )
     )
-    .then((T newValue) {
+    .then<Null>((T newValue) {
       if (!mounted || newValue == null)
         return;
       if (config.onSelected != null)

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

@@ -57,7 +57,7 @@ class TabController extends ChangeNotifier {
     if (duration != null) {
       _indexIsChangingCount += 1;
       _animationController
-        ..animateTo(_index.toDouble(), duration: duration, curve: curve).then((_) {
+        ..animateTo(_index.toDouble(), duration: duration, curve: curve).whenComplete(() {
           _indexIsChangingCount -= 1;
           notifyListeners();
         });

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

@@ -56,7 +56,7 @@ abstract class AssetBundle {
   ///
   /// Implementations may cache the result, so a particular key should only be
   /// used with one parser for the lifetime of the asset bundle.
-  Future<dynamic> loadStructuredData(String key, Future<dynamic> parser(String value));
+  Future<dynamic> loadStructuredData<T>(String key, Future<T> parser(String value));
 
   /// If this is a caching asset bundle, and the given key describes a cached
   /// asset, then evict the asset from the cache so that the next time it is
@@ -100,7 +100,7 @@ class NetworkAssetBundle extends AssetBundle {
   /// The result is not cached. The parser is run each time the resource is
   /// fetched.
   @override
-  Future<dynamic> loadStructuredData(String key, Future<dynamic> parser(String value)) async {
+  Future<dynamic> loadStructuredData<T>(String key, Future<T> parser(String value)) async {
     assert(key != null);
     assert(parser != null);
     return parser(await loadString(key));
@@ -149,14 +149,14 @@ abstract class CachingAssetBundle extends AssetBundle {
   /// subsequent calls will be a [SynchronousFuture], which resolves its
   /// callback synchronously.
   @override
-  Future<dynamic> loadStructuredData(String key, Future<dynamic> parser(String value)) {
+  Future<dynamic> loadStructuredData<T>(String key, Future<T> parser(String value)) {
     assert(key != null);
     assert(parser != null);
     if (_structuredDataCache.containsKey(key))
       return _structuredDataCache[key];
     Completer<dynamic> completer;
     Future<dynamic> result;
-    loadString(key, cache: false).then(parser).then((dynamic value) {
+    loadString(key, cache: false).then<T>(parser).then<Null>((T value) {
       result = new SynchronousFuture<dynamic>(value);
       _structuredDataCache[key] = result;
       if (completer != null) {

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

@@ -163,7 +163,7 @@ abstract class ImageProvider<T> {
     assert(configuration != null);
     final ImageStream stream = new ImageStream();
     T obtainedKey;
-    obtainKey(configuration).then((T key) {
+    obtainKey(configuration).then<Null>((T key) {
       obtainedKey = key;
       stream.setCompleter(imageCache.putIfAbsent(key, () => load(key)));
     }).catchError(

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

@@ -94,7 +94,7 @@ class AssetImage extends AssetBundleImageProvider {
     final AssetBundle chosenBundle = bundle ?? configuration.bundle ?? rootBundle;
     Completer<AssetBundleImageKey> completer;
     Future<AssetBundleImageKey> result;
-    chosenBundle.loadStructuredData(_kAssetManifestFileName, _manifestParser).then(
+    chosenBundle.loadStructuredData<Map<String, List<String>>>(_kAssetManifestFileName, _manifestParser).then<Null>(
       (Map<String, List<String>> manifest) {
         final String chosenName = _chooseVariant(
           name,

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

@@ -239,7 +239,7 @@ class OneFrameImageStreamCompleter extends ImageStreamCompleter {
   /// FlutterErrorDetails]).
   OneFrameImageStreamCompleter(Future<ImageInfo> image, { InformationCollector informationCollector }) {
     assert(image != null);
-    image.then(setImage, onError: (dynamic error, StackTrace stack) {
+    image.then<Null>(setImage, onError: (dynamic error, StackTrace stack) {
       FlutterError.reportError(new FlutterErrorDetails(
         exception: error,
         stack: stack,

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

@@ -163,7 +163,7 @@ class _WidgetsAppState extends State<WidgetsApp> implements WidgetsBindingObserv
   @override
   void didChangeLocale(Locale locale) {
     if (config.onLocaleChanged != null) {
-      config.onLocaleChanged(locale).then((LocaleQueryData data) {
+      config.onLocaleChanged(locale).then<Null>((LocaleQueryData data) {
         if (mounted)
           setState(() { _localeData = data; });
       });

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

@@ -423,7 +423,7 @@ class _DragTargetState<T> extends State<DragTarget<T>> {
     return new MetaData(
       metaData: this,
       behavior: HitTestBehavior.translucent,
-      child: config.builder(context, _mapAvatarsToData<T>(_candidateAvatars), _mapAvatarsToData(_rejectedAvatars))
+      child: config.builder(context, _mapAvatarsToData<T>(_candidateAvatars), _mapAvatarsToData<dynamic>(_rejectedAvatars))
     );
   }
 }

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

@@ -338,7 +338,7 @@ abstract class PageableState<T extends Pageable> extends ScrollableState<T> {
       .then(_notifyPageChanged);
   }
 
-  void _notifyPageChanged(_) {
+  void _notifyPageChanged(Null value) {
     if (config.onPageChanged != null)
       config.onPageChanged(_scrollOffsetToPageIndex(scrollOffset));
   }

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

@@ -557,7 +557,7 @@ class AbsoluteBallisticScrollActivity extends ScrollActivity {
     )
       ..addListener(_tick)
       ..animateWith(simulation)
-       .then(_end);
+       .whenComplete(_end);
   }
 
   @override
@@ -587,7 +587,7 @@ class AbsoluteBallisticScrollActivity extends ScrollActivity {
       position.beginIdleActivity();
   }
 
-  void _end(Null value) {
+  void _end() {
     position.beginIdleActivity();
   }
 
@@ -636,7 +636,7 @@ class AbsoluteDrivenScrollActivity extends ScrollActivity {
     )
       ..addListener(_tick)
       ..animateTo(to, duration: duration, curve: curve)
-       .then(_end);
+       .whenComplete(_end);
   }
 
   @override
@@ -659,7 +659,7 @@ class AbsoluteDrivenScrollActivity extends ScrollActivity {
       position.beginIdleActivity();
   }
 
-  void _end(Null value) {
+  void _end() {
     position.beginBallisticActivity(velocity);
   }
 

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

@@ -1312,7 +1312,7 @@ class ScrollableState<T extends Scrollable> extends State<T> with SingleTickerPr
       config.onScroll(_scrollOffset);
   }
 
-  void _handleDragDown(_) {
+  void _handleDragDown(DragDownDetails details) {
     setState(() {
       _stop();
     });
@@ -1356,7 +1356,7 @@ class ScrollableState<T extends Scrollable> extends State<T> with SingleTickerPr
 
   void _handleDragEnd(DragEndDetails details) {
     final double scrollVelocity = pixelDeltaToScrollOffset(details.velocity.pixelsPerSecond);
-    fling(scrollVelocity).then((Null _) {
+    fling(scrollVelocity).then<Null>((Null value) {
       _endScroll(details: details);
     });
   }

packages/flutter/test/cupertino/dialog_test.dart

@@ -17,7 +17,7 @@ void main() {
             builder: (BuildContext context) {
               return new RaisedButton(
                 onPressed: () {
-                  showDialog(
+                  showDialog<Null>(
                     context: context,
                     child: new CupertinoAlertDialog(
                       title: new Text('The title'),

packages/flutter/test/foundation/capture_output.dart

@@ -8,7 +8,7 @@ import 'dart:ui' show VoidCallback;
 List<String> captureOutput(VoidCallback fn) {
   List<String> log = <String>[];
 
-  runZoned(fn, zoneSpecification: new ZoneSpecification(
+  runZoned<Null>(fn, zoneSpecification: new ZoneSpecification(
     print: (Zone self,
             ZoneDelegate parent,
             Zone zone,

packages/flutter/test/foundation/synchronous_future_test.dart

@@ -12,13 +12,13 @@ void main() {
     Future<int> future = new SynchronousFuture<int>(42);
 
     int result;
-    future.then((int value) { result = value; });
+    future.then<Null>((int value) { result = value; });
 
     expect(result, equals(42));
     result = null;
 
     Future<int> futureWithTimeout = future.timeout(const Duration(milliseconds: 1));
-    futureWithTimeout.then((int value) { result = value; });
+    futureWithTimeout.then<Null>((int value) { result = value; });
     expect(result, isNull);
     await futureWithTimeout;
     expect(result, equals(42));

packages/flutter/test/material/dialog_test.dart

@@ -18,7 +18,7 @@ void main() {
                 child: new RaisedButton(
                   child: new Text('X'),
                   onPressed: () {
-                    showDialog(
+                    showDialog<Null>(
                       context: context,
                       child: new AlertDialog(
                         content: new Container(
@@ -68,7 +68,7 @@ void main() {
                 child: new RaisedButton(
                   child: new Text('X'),
                   onPressed: () {
-                    showDialog(
+                    showDialog<Null>(
                       context: context,
                       child: new AlertDialog(
                         title: new Text('Title'),

packages/flutter/test/material/scaffold_test.dart

@@ -211,7 +211,7 @@ void main() {
             builder: (BuildContext context) {
               return new GestureDetector(
                 onTap: () {
-                  Scaffold.of(context).showBottomSheet((BuildContext context) {
+                  Scaffold.of(context).showBottomSheet<Null>((BuildContext context) {
                     return new Container(
                       key: sheetKey,
                       decoration: new BoxDecoration(backgroundColor: Colors.blue[500])

packages/flutter/test/material/snack_bar_test.dart

@@ -356,7 +356,7 @@ void main() {
                       actionPressed = true;
                     }
                   ),
-                )).closed.then((SnackBarClosedReason reason) {
+                )).closed.then<Null>((SnackBarClosedReason reason) {
                   closedReason = reason;
                 });
               },

packages/flutter/test/material/theme_test.dart

@@ -135,7 +135,7 @@ void main() {
                 builder: (BuildContext context) {
                   return new RaisedButton(
                     onPressed: () {
-                      showModalBottomSheet(
+                      showModalBottomSheet<Null>(
                         context: context,
                         builder: (BuildContext context) => new Text('bottomSheet'),
                       );
@@ -172,7 +172,7 @@ void main() {
                 builder: (BuildContext context) {
                   return new RaisedButton(
                     onPressed: () {
-                      showDialog(
+                      showDialog<Null>(
                         context: context,
                         child: new Text('dialog'),
                       );
@@ -204,7 +204,7 @@ void main() {
               builder: (BuildContext context) {
                 return new GestureDetector(
                   onTap: () {
-                    showDialog(
+                    showDialog<Null>(
                       context: context,
                       child: new Scaffold(
                         body: const SizedBox(

packages/flutter/test/material/will_pop_test.dart

@@ -65,7 +65,7 @@ void main() {
                 child: new FlatButton(
                   child: new Text('X'),
                   onPressed: () {
-                    showDialog(
+                    showDialog<Null>(
                       context: context,
                       child: new SamplePage(),
                     );

packages/flutter/test/widgets/bottom_sheet_test.dart

@@ -26,7 +26,7 @@ void main() {
     showModalBottomSheet<Null>(
       context: savedContext,
       builder: (BuildContext context) => new Text('BottomSheet')
-    ).then((Null result) {
+    ).then<Null>((Null result) {
       expectSync(result, isNull);
       showBottomSheetThenCalled = true;
     });
@@ -48,7 +48,7 @@ void main() {
     showModalBottomSheet<Null>(
       context: savedContext,
       builder: (BuildContext context) => new Text('BottomSheet'),
-    ).then((Null result) {
+    ).then<Null>((Null result) {
       expectSync(result, isNull);
       showBottomSheetThenCalled = true;
     });
@@ -80,12 +80,12 @@ void main() {
     expect(showBottomSheetThenCalled, isFalse);
     expect(find.text('BottomSheet'), findsNothing);
 
-    scaffoldKey.currentState.showBottomSheet((BuildContext context) {
+    scaffoldKey.currentState.showBottomSheet<Null>((BuildContext context) {
       return new Container(
         margin: const EdgeInsets.all(40.0),
         child: new Text('BottomSheet')
       );
-    }).closed.then((_) {
+    }).closed.whenComplete(() {
       showBottomSheetThenCalled = true;
     });
 
@@ -130,7 +130,7 @@ void main() {
       )
     ));
 
-    scaffoldKey.currentState.showBottomSheet((BuildContext context) {
+    scaffoldKey.currentState.showBottomSheet<Null>((BuildContext context) {
       return new Container(
         margin: const EdgeInsets.all(40.0),
         child: new Text('BottomSheet')

packages/flutter/test/widgets/image_resolution_test.dart

@@ -87,8 +87,8 @@ class TestAssetImage extends AssetImage {
   @override
   Future<ImageInfo> loadAsync(AssetBundleImageKey key) {
     ImageInfo result;
-    key.bundle.load(key.name).then((ByteData data) {
-      decodeImage(data).then((ui.Image image) {
+    key.bundle.load(key.name).then<Null>((ByteData data) {
+      decodeImage(data).then<Null>((ui.Image image) {
         result = new ImageInfo(image: image, scale: key.scale);
       });
     });

packages/flutter/test/widgets/page_transitions_test.dart

@@ -29,7 +29,7 @@ class PersistentBottomSheetTestState extends State<PersistentBottomSheetTest> {
     _scaffoldKey.currentState.showBottomSheet<Null>((BuildContext context) {
       return new Text('bottomSheet');
     })
-    .closed.then((_) {
+    .closed.whenComplete(() {
       setState(() {
         setStateCalled = true;
       });
@@ -421,13 +421,13 @@ void main() {
     );
 
     int popCount = 0;
-    route.popped.then((_) {
-      ++popCount;
+    route.popped.whenComplete(() {
+      popCount += 1;
     });
 
     int completeCount = 0;
-    route.completed.then((_) {
-      ++completeCount;
+    route.completed.whenComplete(() {
+      completeCount += 1;
     });
 
     expect(popCount, 0);

packages/flutter/test/widgets/set_state_1_test.dart

@@ -19,7 +19,7 @@ class InsideState extends State<Inside> {
     );
   }
 
-  void _handlePointerDown(_) {
+  void _handlePointerDown(PointerDownEvent event) {
     setState(() { });
   }
 }
@@ -42,7 +42,7 @@ class MiddleState extends State<Middle> {
     );
   }
 
-  void _handlePointerDown(_) {
+  void _handlePointerDown(PointerDownEvent event) {
     setState(() { });
   }
 }

packages/flutter_test/lib/src/binding.dart

@@ -360,7 +360,7 @@ abstract class TestWidgetsFlutterBinding extends BindingBase
         ));
         assert(_parentZone != null);
         assert(_pendingExceptionDetails != null);
-        _parentZone.run(_testCompletionHandler);
+        _parentZone.run<Null>(_testCompletionHandler);
       }
     );
     _parentZone = Zone.current;

packages/flutter_tools/lib/executable.dart

@@ -162,7 +162,7 @@ Future<Null> main(List<String> args) async {
           else
             stderr.writeln('Oops; flutter has exited unexpectedly.');
 
-          _createCrashReport(args, error, chain).then((File file) {
+          _createCrashReport(args, error, chain).then<Null>((File file) {
             stderr.writeln(
                 'Crash report written to ${file.path};\n'
                     'please let us know at https://github.com/flutter/flutter/issues.'

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

@@ -587,12 +587,11 @@ class _AdbLogReader extends DeviceLogReader {
         _timeOrigin = _adbTimestampToDateTime(lastTimestamp);
     else
         _timeOrigin = null;
-    runCommand(device.adbCommandForDevice(args)).then((Process process) {
+    runCommand(device.adbCommandForDevice(args)).then<Null>((Process process) {
       _process = process;
       _process.stdout.transform(UTF8.decoder).transform(const LineSplitter()).listen(_onLine);
       _process.stderr.transform(UTF8.decoder).transform(const LineSplitter()).listen(_onLine);
-
-      _process.exitCode.then((int code) {
+      _process.exitCode.whenComplete(() {
         if (_linesController.hasListener)
           _linesController.close();
       });

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

@@ -110,7 +110,7 @@ Future<int> runCommandAndStreamOutput(List<String> cmd, {
 
   // Wait for stdout to be fully processed
   // because process.exitCode may complete first causing flaky tests.
-  await subscription.asFuture();
+  await subscription.asFuture<Null>();
   subscription.cancel();
 
   return await process.exitCode;

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

@@ -410,13 +410,14 @@ class RecordingProcessManager implements ProcessManager {
     await files.forEach((FileSystemEntity entity) {
       File file = entity;
       Future<dynamic> readAsBytes = file.readAsBytes();
-      addAllFilesToArchive.add(readAsBytes.then((List<int> data) {
+      addAllFilesToArchive.add(readAsBytes.then<Null>((List<int> data) {
         archive.addFile(new ArchiveFile.noCompress(
-          path.basename(file.path), data.length, data));
+          path.basename(file.path), data.length, data)
+        );
       }));
     });
 
-    await Future.wait(addAllFilesToArchive);
+    await Future.wait<dynamic>(addAllFilesToArchive);
     return new ZipEncoder().encode(archive);
   }
 }

packages/flutter_tools/lib/src/cache.dart

@@ -232,7 +232,7 @@ class MaterialFonts {
 
     return Cache._downloadFileToCache(
       Uri.parse(cache.getVersionFor(kName)), fontsDir, true
-    ).then((_) {
+    ).then<Null>((Null value) {
       cache.setStampFor(kName, cache.getVersionFor(kName));
       status.stop();
     }).whenComplete(() {
@@ -401,7 +401,7 @@ class FlutterEngine {
 
   Future<Null> _downloadItem(String message, String url, Directory dest) {
     Status status = logger.startProgress(message);
-    return Cache._downloadFileToCache(Uri.parse(url), dest, true).then((_) {
+    return Cache._downloadFileToCache(Uri.parse(url), dest, true).then<Null>((Null value) {
       status.stop();
     }).whenComplete(() {
       status.cancel();

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

@@ -120,7 +120,7 @@ class AnalyzeContinuously extends AnalyzeBase {
 
       if (firstAnalysis && isBenchmarking) {
         writeBenchmark(analysisTimer, issueCount, -1); // TODO(ianh): track members missing dartdocs instead of saying -1
-        server.dispose().then((_) => exit(issueCount > 0 ? 1 : 0));
+        server.dispose().whenComplete(() { exit(issueCount > 0 ? 1 : 0); });
       }
 
       firstAnalysis = false;

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

@@ -171,7 +171,7 @@ abstract class Domain {
       if (_handlers.containsKey(command))
         return _handlers[command](args);
       throw 'command not understood: $name.$command';
-    }).then((dynamic result) {
+    }).then<Null>((dynamic result) {
       if (result == null) {
         _send(<String, dynamic>{'id': id});
       } else {
@@ -386,7 +386,7 @@ class AppDomain extends Domain {
 
     if (options.debuggingEnabled) {
       connectionInfoCompleter = new Completer<DebugConnectionInfo>();
-      connectionInfoCompleter.future.then((DebugConnectionInfo info) {
+      connectionInfoCompleter.future.then<Null>((DebugConnectionInfo info) {
         Map<String, dynamic> params = <String, dynamic>{
           'port': info.httpUri.port,
           'wsUri': info.wsUri.toString(),
@@ -397,7 +397,7 @@ class AppDomain extends Domain {
       });
     }
     Completer<Null> appStartedCompleter = new Completer<Null>();
-    appStartedCompleter.future.then((_) {
+    appStartedCompleter.future.then<Null>((Null value) {
       _sendAppEvent(app, 'started');
     });
 

packages/flutter_tools/lib/src/devfs.dart

@@ -266,7 +266,7 @@ class _DevFSHttpWriter {
       Stream<List<int>> contents = content.contentsAsCompressedStream();
       await request.addStream(contents);
       HttpClientResponse response = await request.close();
-      await response.drain();
+      await response.drain<Null>();
     } catch (e) {
       printError('Error writing "$devicePath" to DevFS: $e');
     }
@@ -417,7 +417,10 @@ class DevFS {
         if (progressReporter != null) {
           final int max = _pendingOperations.length;
           int complete = 0;
-          _pendingOperations.forEach((Future<dynamic> f) => f.then((dynamic v) {
+          _pendingOperations.forEach((Future<dynamic> f) => f.whenComplete(() {
+            // TODO(ianh): If one of the pending operations fail, we'll keep
+            // calling progressReporter long after update() has completed its
+            // future, assuming that doesn't crash the app.
             complete += 1;
             progressReporter(complete, max);
           }));

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

@@ -402,12 +402,11 @@ class _IOSDeviceLogReader extends DeviceLogReader {
   String get name => device.name;
 
   void _start() {
-    runCommand(<String>[device.loggerPath]).then((Process process) {
+    runCommand(<String>[device.loggerPath]).then<Null>((Process process) {
       _process = process;
       _process.stdout.transform(UTF8.decoder).transform(const LineSplitter()).listen(_onLine);
       _process.stderr.transform(UTF8.decoder).transform(const LineSplitter()).listen(_onLine);
-
-      _process.exitCode.then((int code) {
+      _process.exitCode.whenComplete(() {
         if (_linesController.hasListener)
           _linesController.close();
       });

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

@@ -663,7 +663,7 @@ class _IOSSimulatorLogReader extends DeviceLogReader {
     _systemProcess.stdout.transform(UTF8.decoder).transform(const LineSplitter()).listen(_onSystemLine);
     _systemProcess.stderr.transform(UTF8.decoder).transform(const LineSplitter()).listen(_onSystemLine);
 
-    _deviceProcess.exitCode.then((int code) {
+    _deviceProcess.exitCode.whenComplete(() {
       if (_linesController.hasListener)
         _linesController.close();
     });

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

@@ -35,7 +35,7 @@ class CoverageCollector {
 
     int pid = process.pid;
     int exitCode;
-    process.exitCode.then((int code) {
+    process.exitCode.then<Null>((int code) {
       exitCode = code;
     });
 

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

@@ -124,7 +124,7 @@ class FlutterPlatform extends PlatformPlugin {
     bool subprocessActive = false;
     bool controllerSinkClosed = false;
     try {
-      controller.sink.done.then((_) { controllerSinkClosed = true; });
+      controller.sink.done.whenComplete(() { controllerSinkClosed = true; });
 
       // Prepare our WebSocket server to talk to the engine subproces.
       HttpServer server = await HttpServer.bind(_kHost, 0);
@@ -524,10 +524,10 @@ class _FlutterPlatformStreamSinkWrapper<S> implements StreamSink<S> {
 
   @override
   Future<dynamic> close() {
-   Future.wait(<Future<dynamic>>[
+   Future.wait<dynamic>(<Future<dynamic>>[
       _parent.close(),
       _shellProcessClosed,
-    ]).then(
+    ]).then<Null>(
       (List<dynamic> value) {
         _done.complete();
       },

packages/flutter_tools/lib/src/vmservice.dart

@@ -561,7 +561,7 @@ class VM extends ServiceObjectOwner {
   Future<Isolate> getIsolate(String isolateId) {
     if (!loaded) {
       // Trigger a VM load, then get the isolate. Ignore any errors.
-      return load().then((_) => getIsolate(isolateId)).catchError((_) => null);
+      return load().then<Isolate>((ServiceObject serviceObject) => getIsolate(isolateId)).catchError((dynamic error) => null);
     }
     return new Future<Isolate>.value(_isolateCache[isolateId]);
   }

packages/flutter_tools/lib/src/zip.dart

@@ -37,9 +37,9 @@ class _ArchiveZipBuilder extends ZipBuilder {
     final Completer<Null> finished = new Completer<Null>();
     int count = entries.length;
     entries.forEach((String archivePath, DevFSContent content) {
-      content.contentsAsBytes().then((List<int> data) {
+      content.contentsAsBytes().then<Null>((List<int> data) {
         archive.addFile(new ArchiveFile.noCompress(archivePath, data.length, data));
-        --count;
+        count -= 1;
         if (count == 0)
           finished.complete();
       });
@@ -73,11 +73,11 @@ class _ZipToolBuilder extends ZipBuilder {
     final Completer<Null> finished = new Completer<Null>();
     int count = entries.length;
     entries.forEach((String archivePath, DevFSContent content) {
-      content.contentsAsBytes().then((List<int> data) {
+      content.contentsAsBytes().then<Null>((List<int> data) {
         File file = fs.file(path.join(zipBuildDir.path, archivePath));
         file.parent.createSync(recursive: true);
-        file.writeAsBytes(data).then((_) {
-          --count;
+        file.writeAsBytes(data).then<Null>((File value) {
+          count -= 1;
           if (count == 0)
             finished.complete();
         });

packages/flutter_tools/test/analyze_duplicate_names_test.dart

@@ -34,7 +34,7 @@ void main() {
       applyMocksToCommand(command);
       return createTestCommandRunner(command).run(
         <String>['analyze', '--no-current-package', '--no-current-directory', dartFileA.path, dartFileB.path]
-      ).then((_) {
+      ).then<Null>((Null value) {
         expect(testLogger.statusText, startsWith('Analyzing 2 files...\nNo analyzer warnings!'));
       });
 

packages/flutter_tools/test/daemon_test.dart

@@ -118,7 +118,7 @@ void main() {
         notifyingLogger: notifyingLogger
       );
       commands.add(<String, dynamic>{'id': 0, 'method': 'daemon.shutdown'});
-      return daemon.onExit.then((int code) {
+      return daemon.onExit.then<Null>((int code) {
         responses.close();
         commands.close();
         expect(code, 0);

packages/flutter_tools/test/data/dart_dependencies_test/good/.analysis_options

 analyzer:
- exclude:
+  exclude:
     - '**'

packages/flutter_tools/test/data/dart_dependencies_test/syntax_error/.analysis_options

 analyzer:
- exclude:
+  exclude:
     - '**'

packages/flutter_tools/test/devfs_test.dart

@@ -268,7 +268,7 @@ class MockVMService extends BasicMock implements VMService {
       String fsName = request.headers.value('dev_fs_name');
       String devicePath = UTF8.decode(BASE64.decode(request.headers.value('dev_fs_path_b64')));
       messages.add('writeFile $fsName $devicePath');
-      request.drain().then((_) {
+      request.drain<List<int>>().then<Null>((List<int> value) {
         request.response
           ..write('Got it')
           ..close();

packages/flutter_tools/test/drive_test.dart

@@ -47,13 +47,13 @@ void main() {
       targetDeviceFinder = () {
         throw 'Unexpected call to targetDeviceFinder';
       };
-      appStarter = (_) {
+      appStarter = (DriveCommand command) {
         throw 'Unexpected call to appStarter';
       };
-      testRunner = (_) {
+      testRunner = (List<String> testArgs) {
         throw 'Unexpected call to testRunner';
       };
-      appStopper = (_) {
+      appStopper = (DriveCommand command) {
         throw 'Unexpected call to appStopper';
       };
     });
@@ -86,14 +86,14 @@ void main() {
 
     testUsingContext('returns 1 when app fails to run', () async {
       withMockDevice();
-      appStarter = expectAsync((_) async => 1);
+      appStarter = expectAsync((DriveCommand command) async => 1);
 
       String testApp = '/some/app/test_driver/e2e.dart';
       String testFile = '/some/app/test_driver/e2e_test.dart';
 
       MemoryFileSystem memFs = memoryFileSystem;
-      await memFs.file(testApp).writeAsString('main() {}');
-      await memFs.file(testFile).writeAsString('main() {}');
+      await memFs.file(testApp).writeAsString('main() { }');
+      await memFs.file(testFile).writeAsString('main() { }');
 
       List<String> args = <String>[
         'drive',
@@ -155,14 +155,14 @@ void main() {
       String testApp = '/some/app/test/e2e.dart';
       String testFile = '/some/app/test_driver/e2e_test.dart';
 
-      appStarter = expectAsync((_) {
+      appStarter = expectAsync((DriveCommand command) {
         return new Future<int>.value(0);
       });
       testRunner = expectAsync((List<String> testArgs) {
         expect(testArgs, <String>[testFile]);
         return new Future<int>.value(0);
       });
-      appStopper = expectAsync((_) {
+      appStopper = expectAsync((DriveCommand command) {
         return new Future<int>.value(0);
       });
 
@@ -186,13 +186,13 @@ void main() {
       String testApp = '/some/app/test/e2e.dart';
       String testFile = '/some/app/test_driver/e2e_test.dart';
 
-      appStarter = expectAsync((_) {
+      appStarter = expectAsync((DriveCommand command) {
         return new Future<int>.value(0);
       });
-      testRunner = (_) {
+      testRunner = (List<String> testArgs) {
         throwToolExit(null, exitCode: 123);
       };
-      appStopper = expectAsync((_) {
+      appStopper = expectAsync((DriveCommand command) {
         return new Future<int>.value(0);
       });
 

packages/flutter_tools/tool/daemon_client.dart

@@ -70,7 +70,7 @@ Future<Null> main() async {
     stdout.write('> ');
   });
 
-  daemon.exitCode.then((int code) {
+  daemon.exitCode.then<Null>((int code) {
     print('daemon exiting ($code)');
     exit(code);
   });