implicit-casts:false in flutter_test (#44996)

packages/flutter_test/analysis_options.yaml

+include: ../analysis_options.yaml
+
+analyzer:
+  strong-mode:
+    implicit-casts: false
+    implicit-dynamic: false
+
+linter:
+  rules:
+    avoid_as: false # Disabled so we can gradually migrate to no implicit dynamic.

packages/flutter_test/lib/src/_goldens_io.dart

@@ -135,7 +135,7 @@ class LocalComparisonOutput {
     if (result.diffs != null) {
       additionalFeedback = '\nFailure feedback can be found at '
         '${path.join(basedir.path, 'failures')}';
-      final Map<String, Image> diffs = result.diffs;
+      final Map<String, Image> diffs = result.diffs.cast<String, Image>();
       diffs.forEach((String name, Image image) {
         final File output = getFailureFile(
           key.isEmpty ? name : name + '_' + key,

packages/flutter_test/lib/src/accessibility.dart

@@ -196,7 +196,7 @@ class MinimumTextContrastGuideline extends AccessibilityGuideline {
   Future<Evaluation> evaluate(WidgetTester tester) async {
     final SemanticsNode root = tester.binding.pipelineOwner.semanticsOwner.rootSemanticsNode;
     final RenderView renderView = tester.binding.renderView;
-    final OffsetLayer layer = renderView.debugLayer;
+    final OffsetLayer layer = renderView.debugLayer as OffsetLayer;
     ui.Image image;
     final ByteData byteData = await tester.binding.runAsync<ByteData>(() async {
       // Needs to be the same pixel ratio otherwise our dimensions won't match the
@@ -231,7 +231,7 @@ class MinimumTextContrastGuideline extends AccessibilityGuideline {
       Rect paintBounds;
       if (elements.length == 1) {
         final Element element = elements.single;
-        final RenderBox renderObject = element.renderObject;
+        final RenderBox renderObject = element.renderObject as RenderBox;
         element.renderObject.paintBounds;
         paintBounds = Rect.fromPoints(
           renderObject.localToGlobal(element.renderObject.paintBounds.topLeft - const Offset(4.0, 4.0)),
@@ -406,15 +406,15 @@ class _ContrastReport {
     if (r <= 0.03928)
       r /= 12.92;
     else
-      r = math.pow((r + 0.055)/ 1.055, 2.4);
+      r = math.pow((r + 0.055)/ 1.055, 2.4).toDouble();
     if (g <= 0.03928)
       g /= 12.92;
     else
-      g = math.pow((g + 0.055)/ 1.055, 2.4);
+      g = math.pow((g + 0.055)/ 1.055, 2.4).toDouble();
     if (b <= 0.03928)
       b /= 12.92;
     else
-      b = math.pow((b + 0.055)/ 1.055, 2.4);
+      b = math.pow((b + 0.055)/ 1.055, 2.4).toDouble();
     return 0.2126 * r + 0.7152 * g + 0.0722 * b;
   }
 }

packages/flutter_test/lib/src/binding.dart

@@ -1335,7 +1335,7 @@ class LiveTestWidgetsFlutterBinding extends TestWidgetsFlutterBinding {
   }
 
   @override
-  _LiveTestRenderView get renderView => super.renderView;
+  _LiveTestRenderView get renderView => super.renderView as _LiveTestRenderView;
 
   void _handleViewNeedsPaint() {
     _viewNeedsPaint = true;
@@ -1577,7 +1577,7 @@ class _LiveTestRenderView extends RenderView {
   }) : super(configuration: configuration, window: window);
 
   @override
-  TestViewConfiguration get configuration => super.configuration;
+  TestViewConfiguration get configuration => super.configuration as TestViewConfiguration;
   @override
   set configuration(covariant TestViewConfiguration value) { super.configuration = value; }
 

packages/flutter_test/lib/src/controller.dart

@@ -62,7 +62,7 @@ abstract class WidgetController {
   /// * Use [widgetList] if you expect to match several widgets and want all of them.
   T widget<T extends Widget>(Finder finder) {
     TestAsyncUtils.guardSync();
-    return finder.evaluate().single.widget;
+    return finder.evaluate().single.widget as T;
   }
 
   /// The first matching widget according to a depth-first pre-order
@@ -73,7 +73,7 @@ abstract class WidgetController {
   /// * Use [widget] if you only expect to match one widget.
   T firstWidget<T extends Widget>(Finder finder) {
     TestAsyncUtils.guardSync();
-    return finder.evaluate().first.widget;
+    return finder.evaluate().first.widget as T;
   }
 
   /// The matching widgets in the widget tree.
@@ -83,7 +83,7 @@ abstract class WidgetController {
   Iterable<T> widgetList<T extends Widget>(Finder finder) {
     TestAsyncUtils.guardSync();
     return finder.evaluate().map<T>((Element element) {
-      final T result = element.widget;
+      final T result = element.widget as T;
       return result;
     });
   }
@@ -107,7 +107,7 @@ abstract class WidgetController {
   /// * Use [elementList] if you expect to match several elements and want all of them.
   T element<T extends Element>(Finder finder) {
     TestAsyncUtils.guardSync();
-    return finder.evaluate().single;
+    return finder.evaluate().single as T;
   }
 
   /// The first matching element according to a depth-first pre-order
@@ -118,7 +118,7 @@ abstract class WidgetController {
   /// * Use [element] if you only expect to match one element.
   T firstElement<T extends Element>(Finder finder) {
     TestAsyncUtils.guardSync();
-    return finder.evaluate().first;
+    return finder.evaluate().first as T;
   }
 
   /// The matching elements in the widget tree.
@@ -127,7 +127,7 @@ abstract class WidgetController {
   /// * Use [firstElement] if you expect to match several but only want the first.
   Iterable<T> elementList<T extends Element>(Finder finder) {
     TestAsyncUtils.guardSync();
-    return finder.evaluate();
+    return finder.evaluate().cast<T>();
   }
 
   /// All states currently in the widget tree (lazy pre-order traversal).
@@ -179,7 +179,7 @@ abstract class WidgetController {
   T _stateOf<T extends State>(Element element, Finder finder) {
     TestAsyncUtils.guardSync();
     if (element is StatefulElement)
-      return element.state;
+      return element.state as T;
     throw StateError('Widget of type ${element.widget.runtimeType}, with ${finder.description}, is not a StatefulWidget.');
   }
 
@@ -204,7 +204,7 @@ abstract class WidgetController {
   /// * Use [renderObjectList] if you expect to match several render objects and want all of them.
   T renderObject<T extends RenderObject>(Finder finder) {
     TestAsyncUtils.guardSync();
-    return finder.evaluate().single.renderObject;
+    return finder.evaluate().single.renderObject as T;
   }
 
   /// The render object of the first matching widget according to a
@@ -215,7 +215,7 @@ abstract class WidgetController {
   /// * Use [renderObject] if you only expect to match one render object.
   T firstRenderObject<T extends RenderObject>(Finder finder) {
     TestAsyncUtils.guardSync();
-    return finder.evaluate().first.renderObject;
+    return finder.evaluate().first.renderObject as T;
   }
 
   /// The render objects of the matching widgets in the widget tree.
@@ -225,7 +225,7 @@ abstract class WidgetController {
   Iterable<T> renderObjectList<T extends RenderObject>(Finder finder) {
     TestAsyncUtils.guardSync();
     return finder.evaluate().map<T>((Element element) {
-      final T result = element.renderObject;
+      final T result = element.renderObject as T;
       return result;
     });
   }
@@ -644,7 +644,7 @@ abstract class WidgetController {
   Offset _getElementPoint(Finder finder, Offset sizeToPoint(Size size)) {
     TestAsyncUtils.guardSync();
     final Element element = finder.evaluate().single;
-    final RenderBox box = element.renderObject;
+    final RenderBox box = element.renderObject as RenderBox;
     assert(box != null);
     return box.localToGlobal(sizeToPoint(box.size));
   }
@@ -654,7 +654,7 @@ abstract class WidgetController {
   Size getSize(Finder finder) {
     TestAsyncUtils.guardSync();
     final Element element = finder.evaluate().single;
-    final RenderBox box = element.renderObject;
+    final RenderBox box = element.renderObject as RenderBox;
     assert(box != null);
     return box.size;
   }

packages/flutter_test/lib/src/finders.dart

@@ -501,7 +501,7 @@ class _HitTestableFinder extends ChainedFinder {
   @override
   Iterable<Element> filter(Iterable<Element> parentCandidates) sync* {
     for (final Element candidate in parentCandidates) {
-      final RenderBox box = candidate.renderObject;
+      final RenderBox box = candidate.renderObject as RenderBox;
       assert(box != null);
       final Offset absoluteOffset = box.localToGlobal(alignment.alongSize(box.size));
       final HitTestResult hitResult = HitTestResult();
@@ -544,14 +544,13 @@ class _TextFinder extends MatchFinder {
 
   @override
   bool matches(Element candidate) {
-    if (candidate.widget is Text) {
-      final Text textWidget = candidate.widget;
-      if (textWidget.data != null)
-        return textWidget.data == text;
-      return textWidget.textSpan.toPlainText() == text;
-    } else if (candidate.widget is EditableText) {
-      final EditableText editable = candidate.widget;
-      return editable.controller.text == text;
+    final Widget widget = candidate.widget;
+    if (widget is Text) {
+      if (widget.data != null)
+        return widget.data == text;
+      return widget.textSpan.toPlainText() == text;
+    } else if (widget is EditableText) {
+      return widget.controller.text == text;
     }
     return false;
   }

packages/flutter_test/lib/src/matchers.dart

@@ -662,7 +662,7 @@ class _FindsWidgetMatcher extends Matcher {
     Map<dynamic, dynamic> matchState,
     bool verbose,
   ) {
-    final Finder finder = matchState[Finder];
+    final Finder finder = matchState[Finder] as Finder;
     final int count = finder.evaluate().length;
     if (count == 0) {
       assert(min != null && min > 0);
@@ -790,7 +790,7 @@ class _EqualsIgnoringHashCodes extends Matcher {
 
   @override
   bool matches(dynamic object, Map<dynamic, dynamic> matchState) {
-    final String description = _normalize(object);
+    final String description = _normalize(object as String);
     if (_value != description) {
       matchState[_mismatchedValueKey] = description;
       return false;
@@ -811,7 +811,7 @@ class _EqualsIgnoringHashCodes extends Matcher {
     bool verbose,
   ) {
     if (matchState.containsKey(_mismatchedValueKey)) {
-      final String actualValue = matchState[_mismatchedValueKey];
+      final String actualValue = matchState[_mismatchedValueKey] as String;
       // Leading whitespace is added so that lines in the multi-line
       // description returned by addDescriptionOf are all indented equally
       // which makes the output easier to read for this case.
@@ -860,7 +860,7 @@ class _HasGoodToStringDeep extends Matcher {
   @override
   bool matches(dynamic object, Map<dynamic, dynamic> matchState) {
     final List<String> issues = <String>[];
-    String description = object.toStringDeep();
+    String description = object.toStringDeep() as String;
     if (description.endsWith('\n')) {
       // Trim off trailing \n as the remaining calculations assume
       // the description does not end with a trailing \n.
@@ -898,7 +898,7 @@ class _HasGoodToStringDeep extends Matcher {
     const String prefixOtherLines = 'PREFIX_OTHER_LINES_';
     final List<String> prefixIssues = <String>[];
     String descriptionWithPrefixes =
-        object.toStringDeep(prefixLineOne: prefixLineOne, prefixOtherLines: prefixOtherLines);
+      object.toStringDeep(prefixLineOne: prefixLineOne, prefixOtherLines: prefixOtherLines) as String;
     if (descriptionWithPrefixes.endsWith('\n')) {
       // Trim off trailing \n as the remaining calculations assume
       // the description does not end with a trailing \n.
@@ -944,8 +944,7 @@ class _HasGoodToStringDeep extends Matcher {
     bool verbose,
   ) {
     if (matchState.containsKey(_toStringDeepErrorDescriptionKey)) {
-      return mismatchDescription.add(
-          matchState[_toStringDeepErrorDescriptionKey]);
+      return mismatchDescription.add(matchState[_toStringDeepErrorDescriptionKey] as String);
     }
     return mismatchDescription;
   }
@@ -1030,7 +1029,9 @@ double _rectDistance(Rect a, Rect b) {
 }
 
 double _sizeDistance(Size a, Size b) {
-  final Offset delta = b - a;
+  // TODO(a14n): remove ignore when lint is updated, https://github.com/dart-lang/linter/issues/1843
+  // ignore: unnecessary_parenthesis
+  final Offset delta = (b - a) as Offset;
   return delta.distance;
 }
 
@@ -1063,7 +1064,7 @@ Matcher within<T>({
   @required T from,
   DistanceFunction<T> distanceFunction,
 }) {
-  distanceFunction ??= _kStandardDistanceFunctions[T];
+  distanceFunction ??= _kStandardDistanceFunctions[T] as DistanceFunction<T>;
 
   if (distanceFunction == null) {
     throw ArgumentError(
@@ -1089,7 +1090,7 @@ class _IsWithinDistance<T> extends Matcher {
       return false;
     if (object == value)
       return true;
-    final T test = object;
+    final T test = object as T;
     final num distance = distanceFunction(test, value);
     if (distance < 0) {
       throw ArgumentError(
@@ -1130,7 +1131,7 @@ class _MoreOrLessEquals extends Matcher {
       return false;
     if (object == value)
       return true;
-    final double test = object;
+    final double test = object as double;
     return (test - value).abs() <= epsilon;
   }
 
@@ -1280,7 +1281,7 @@ abstract class _FailWithDescriptionMatcher extends Matcher {
     Map<dynamic, dynamic> matchState,
     bool verbose,
   ) {
-    return mismatchDescription.add(matchState['failure']);
+    return mismatchDescription.add(matchState['failure'] as String);
   }
 }
 
@@ -1325,10 +1326,10 @@ abstract class _MatchRenderObject<M extends RenderObject, T extends RenderObject
     final RenderObject renderObject = nodes.single.renderObject;
 
     if (renderObject.runtimeType == T)
-      return renderObjectMatchesT(matchState, renderObject);
+      return renderObjectMatchesT(matchState, renderObject as T);
 
     if (renderObject.runtimeType == M)
-      return renderObjectMatchesM(matchState, renderObject);
+      return renderObjectMatchesM(matchState, renderObject as M);
 
     return failWithDescription(matchState, 'had a root render object of type: ${renderObject.runtimeType}');
   }
@@ -1363,7 +1364,7 @@ class _RendersOnPhysicalModel extends _MatchRenderObject<RenderPhysicalShape, Re
   bool renderObjectMatchesM(Map<dynamic, dynamic> matchState, RenderPhysicalShape renderObject) {
     if (renderObject.clipper.runtimeType != ShapeBorderClipper)
       return failWithDescription(matchState, 'clipper was: ${renderObject.clipper}');
-    final ShapeBorderClipper shapeClipper = renderObject.clipper;
+    final ShapeBorderClipper shapeClipper = renderObject.clipper as ShapeBorderClipper;
 
     if (borderRadius != null && !assertRoundedRectangle(shapeClipper, borderRadius, matchState))
       return false;
@@ -1393,7 +1394,7 @@ class _RendersOnPhysicalModel extends _MatchRenderObject<RenderPhysicalShape, Re
   bool assertRoundedRectangle(ShapeBorderClipper shapeClipper, BorderRadius borderRadius, Map<dynamic, dynamic> matchState) {
     if (shapeClipper.shape.runtimeType != RoundedRectangleBorder)
       return failWithDescription(matchState, 'had shape border: ${shapeClipper.shape}');
-    final RoundedRectangleBorder border = shapeClipper.shape;
+    final RoundedRectangleBorder border = shapeClipper.shape as RoundedRectangleBorder;
     if (border.borderRadius != borderRadius)
       return failWithDescription(matchState, 'had borderRadius: ${border.borderRadius}');
     return true;
@@ -1431,7 +1432,7 @@ class _RendersOnPhysicalShape extends _MatchRenderObject<RenderPhysicalShape, Re
   bool renderObjectMatchesM(Map<dynamic, dynamic> matchState, RenderPhysicalShape renderObject) {
     if (renderObject.clipper.runtimeType != ShapeBorderClipper)
       return failWithDescription(matchState, 'clipper was: ${renderObject.clipper}');
-    final ShapeBorderClipper shapeClipper = renderObject.clipper;
+    final ShapeBorderClipper shapeClipper = renderObject.clipper as ShapeBorderClipper;
 
     if (shapeClipper.shape != shape)
       return failWithDescription(matchState, 'shape was: ${shapeClipper.shape}');
@@ -1470,10 +1471,10 @@ class _ClipsWithBoundingRect extends _MatchRenderObject<RenderClipPath, RenderCl
   bool renderObjectMatchesM(Map<dynamic, dynamic> matchState, RenderClipPath renderObject) {
     if (renderObject.clipper.runtimeType != ShapeBorderClipper)
       return failWithDescription(matchState, 'clipper was: ${renderObject.clipper}');
-    final ShapeBorderClipper shapeClipper = renderObject.clipper;
+    final ShapeBorderClipper shapeClipper = renderObject.clipper as ShapeBorderClipper;
     if (shapeClipper.shape.runtimeType != RoundedRectangleBorder)
       return failWithDescription(matchState, 'shape was: ${shapeClipper.shape}');
-    final RoundedRectangleBorder border = shapeClipper.shape;
+    final RoundedRectangleBorder border = shapeClipper.shape as RoundedRectangleBorder;
     if (border.borderRadius != BorderRadius.zero)
       return failWithDescription(matchState, 'borderRadius was: ${border.borderRadius}');
     return true;
@@ -1505,10 +1506,10 @@ class _ClipsWithBoundingRRect extends _MatchRenderObject<RenderClipPath, RenderC
   bool renderObjectMatchesM(Map<dynamic, dynamic> matchState, RenderClipPath renderObject) {
     if (renderObject.clipper.runtimeType != ShapeBorderClipper)
       return failWithDescription(matchState, 'clipper was: ${renderObject.clipper}');
-    final ShapeBorderClipper shapeClipper = renderObject.clipper;
+    final ShapeBorderClipper shapeClipper = renderObject.clipper as ShapeBorderClipper;
     if (shapeClipper.shape.runtimeType != RoundedRectangleBorder)
       return failWithDescription(matchState, 'shape was: ${shapeClipper.shape}');
-    final RoundedRectangleBorder border = shapeClipper.shape;
+    final RoundedRectangleBorder border = shapeClipper.shape as RoundedRectangleBorder;
     if (border.borderRadius != borderRadius)
       return failWithDescription(matchState, 'had borderRadius: ${border.borderRadius}');
     return true;
@@ -1528,7 +1529,7 @@ class _ClipsWithShapeBorder extends _MatchRenderObject<RenderClipPath, RenderCli
   bool renderObjectMatchesM(Map<dynamic, dynamic> matchState, RenderClipPath renderObject) {
     if (renderObject.clipper.runtimeType != ShapeBorderClipper)
       return failWithDescription(matchState, 'clipper was: ${renderObject.clipper}');
-    final ShapeBorderClipper shapeClipper = renderObject.clipper;
+    final ShapeBorderClipper shapeClipper = renderObject.clipper as ShapeBorderClipper;
     if (shapeClipper.shape != shape)
       return failWithDescription(matchState, 'shape was: ${shapeClipper.shape}');
     return true;
@@ -1609,7 +1610,7 @@ class _CoversSameAreaAs extends Matcher {
     Map<dynamic, dynamic> matchState,
     bool verbose,
   ) {
-    return mismatchDescription.add(matchState['failure']);
+    return mismatchDescription.add(matchState['failure'] as String);
   }
 
   @override
@@ -1638,11 +1639,11 @@ class _ColorMatcher extends Matcher {
 Future<ui.Image> _captureImage(Element element) {
   RenderObject renderObject = element.renderObject;
   while (!renderObject.isRepaintBoundary) {
-    renderObject = renderObject.parent;
+    renderObject = renderObject.parent as RenderObject;
     assert(renderObject != null);
   }
   assert(!renderObject.debugNeedsPaint);
-  final OffsetLayer layer = renderObject.debugLayer;
+  final OffsetLayer layer = renderObject.debugLayer as OffsetLayer;
   return layer.toImage(renderObject.paintBounds);
 }
 
@@ -1673,7 +1674,7 @@ class _MatchesReferenceImage extends AsyncMatcher {
     } else if (item is ui.Image) {
       imageFuture = Future<ui.Image>.value(item);
     } else {
-      final Finder finder = item;
+      final Finder finder = item as Finder;
       final Iterable<Element> elements = finder.evaluate();
       if (elements.isEmpty) {
         return 'could not be rendered because no widget was found';
@@ -1683,7 +1684,7 @@ class _MatchesReferenceImage extends AsyncMatcher {
       imageFuture = _captureImage(elements.single);
     }
 
-    final TestWidgetsFlutterBinding binding = TestWidgetsFlutterBinding.ensureInitialized();
+    final TestWidgetsFlutterBinding binding = TestWidgetsFlutterBinding.ensureInitialized() as TestWidgetsFlutterBinding;
     return binding.runAsync<String>(() async {
       final ui.Image image = await imageFuture;
       final ByteData bytes = await image.toByteData();
@@ -1727,7 +1728,7 @@ class _MatchesGoldenFile extends AsyncMatcher {
     } else if (item is ui.Image) {
       imageFuture = Future<ui.Image>.value(item);
     } else {
-      final Finder finder = item;
+      final Finder finder = item as Finder;
       final Iterable<Element> elements = finder.evaluate();
       if (elements.isEmpty) {
         return 'could not be rendered because no widget was found';
@@ -1739,7 +1740,7 @@ class _MatchesGoldenFile extends AsyncMatcher {
 
     final Uri testNameUri = goldenFileComparator.getTestUri(key, version);
 
-    final TestWidgetsFlutterBinding binding = TestWidgetsFlutterBinding.ensureInitialized();
+    final TestWidgetsFlutterBinding binding = TestWidgetsFlutterBinding.ensureInitialized() as TestWidgetsFlutterBinding;
     return binding.runAsync<String>(() async {
       final ui.Image image = await imageFuture;
       final ByteData bytes = await image.toByteData(format: ui.ImageByteFormat.png);
@@ -1845,7 +1846,7 @@ class _MatchesSemanticsData extends Matcher {
       description.add(' with custom hints: $hintOverrides');
     if (children != null) {
       description.add(' with children:\n');
-      for (_MatchesSemanticsData child in children)
+      for (_MatchesSemanticsData child in children.cast<_MatchesSemanticsData>())
         child.describe(description);
     }
     return description;
@@ -1858,7 +1859,7 @@ class _MatchesSemanticsData extends Matcher {
     if (node == null)
       return failWithDescription(matchState, 'No SemanticsData provided. '
         'Maybe you forgot to enable semantics?');
-    final SemanticsData data = node is SemanticsNode ? node.getSemanticsData() : node;
+    final SemanticsData data = node is SemanticsNode ? node.getSemanticsData() : (node as SemanticsData);
     if (label != null && label != data.label)
       return failWithDescription(matchState, 'label was: ${data.label}');
     if (hint != null && hint != data.hint)
@@ -1956,7 +1957,7 @@ class _MatchesSemanticsData extends Matcher {
     Map<dynamic, dynamic> matchState,
     bool verbose,
   ) {
-    return mismatchDescription.add(matchState['failure']);
+    return mismatchDescription.add(matchState['failure'] as String);
   }
 }
 

packages/flutter_test/lib/src/test_compat.dart

@@ -23,7 +23,7 @@ import 'package:test_api/test_api.dart';
 
 Declarer _localDeclarer;
 Declarer get _declarer {
-  final Declarer declarer = Zone.current[#test.declarer];
+  final Declarer declarer = Zone.current[#test.declarer] as Declarer;
   if (declarer != null) {
     return declarer;
   }
@@ -58,9 +58,9 @@ Future<void> _runGroup(Suite suiteConfig, Group group, List<Group> parents, _Rep
         if (entry is Group) {
           await _runGroup(suiteConfig, entry, parents, reporter);
         } else if (entry.metadata.skip) {
-          await _runSkippedTest(suiteConfig, entry, parents, reporter);
+          await _runSkippedTest(suiteConfig, entry as Test, parents, reporter);
         } else {
-          final Test test = entry;
+          final Test test = entry as Test;
           await _runLiveTest(suiteConfig, test.load(suiteConfig, groups: parents), reporter);
         }
       }
@@ -154,7 +154,7 @@ Future<void> _runSkippedTest(Suite suiteConfig, Test test, List<Group> parents,
 @isTest
 void test(
   Object description,
-  Function body, {
+  dynamic Function() body, {
   String testOn,
   Timeout timeout,
   dynamic skip,
@@ -163,7 +163,8 @@ void test(
   int retry,
 }) {
   _declarer.test(
-    description.toString(), body,
+    description.toString(),
+    body,
     testOn: testOn,
     timeout: timeout,
     skip: skip,
@@ -221,7 +222,7 @@ void test(
 /// If multiple platforms match, the annotations apply in order as through
 /// they were in nested groups.
 @isTestGroup
-void group(Object description, Function body, { dynamic skip }) {
+void group(Object description, void Function() body, { dynamic skip }) {
   _declarer.group(description.toString(), body, skip: skip);
 }
 
@@ -236,7 +237,7 @@ void group(Object description, Function body, { dynamic skip }) {
 ///
 /// Each callback at the top level or in a given group will be run in the order
 /// they were declared.
-void setUp(Function body) {
+void setUp(dynamic Function() body) {
   _declarer.setUp(body);
 }
 
@@ -253,7 +254,7 @@ void setUp(Function body) {
 /// reverse of the order they were declared.
 ///
 /// See also [addTearDown], which adds tear-downs to a running test.
-void tearDown(Function body) {
+void tearDown(dynamic Function() body) {
   _declarer.tearDown(body);
 }
 
@@ -270,7 +271,7 @@ void tearDown(Function body) {
 /// dependencies between tests that should be isolated. In general, you should
 /// prefer [setUp], and only use [setUpAll] if the callback is prohibitively
 /// slow.
-void setUpAll(Function body) {
+void setUpAll(dynamic Function() body) {
   _declarer.setUpAll(body);
 }
 
@@ -285,7 +286,7 @@ void setUpAll(Function body) {
 /// dependencies between tests that should be isolated. In general, you should
 /// prefer [tearDown], and only use [tearDownAll] if the callback is
 /// prohibitively slow.
-void tearDownAll(Function body) {
+void tearDownAll(dynamic Function() body) {
   _declarer.tearDownAll(body);
 }
 

packages/flutter_test/lib/src/test_text_input.dart

@@ -87,8 +87,8 @@ class TestTextInput {
     log.add(methodCall);
     switch (methodCall.method) {
       case 'TextInput.setClient':
-        _client = methodCall.arguments[0];
-        setClientArgs = methodCall.arguments[1];
+        _client = methodCall.arguments[0] as int;
+        setClientArgs = methodCall.arguments[1] as Map<String, dynamic>;
         break;
       case 'TextInput.clearClient':
         _client = 0;
@@ -97,7 +97,7 @@ class TestTextInput {
           onCleared();
         break;
       case 'TextInput.setEditingState':
-        editingState = methodCall.arguments;
+        editingState = methodCall.arguments as Map<String, dynamic>;
         break;
       case 'TextInput.show':
         _isVisible = true;

packages/flutter_test/lib/src/widget_tester.dart

@@ -107,7 +107,7 @@ void testWidgets(
   Duration initialTimeout,
   bool semanticsEnabled = true,
 }) {
-  final TestWidgetsFlutterBinding binding = TestWidgetsFlutterBinding.ensureInitialized();
+  final TestWidgetsFlutterBinding binding = TestWidgetsFlutterBinding.ensureInitialized() as TestWidgetsFlutterBinding;
   final WidgetTester tester = WidgetTester._(binding);
   test(
     description,
@@ -198,7 +198,7 @@ Future<void> benchmarkWidgets(
     print('└─────────────────────────────────────────────────╌┄┈  🐢');
     return true;
   }());
-  final TestWidgetsFlutterBinding binding = TestWidgetsFlutterBinding.ensureInitialized();
+  final TestWidgetsFlutterBinding binding = TestWidgetsFlutterBinding.ensureInitialized() as TestWidgetsFlutterBinding;
   assert(binding is! AutomatedTestWidgetsFlutterBinding);
   final WidgetTester tester = WidgetTester._(binding);
   SemanticsHandle semanticsHandle;
@@ -284,7 +284,7 @@ class WidgetTester extends WidgetController implements HitTestDispatcher, Ticker
 
   /// The binding instance used by the testing framework.
   @override
-  TestWidgetsFlutterBinding get binding => super.binding;
+  TestWidgetsFlutterBinding get binding => super.binding as TestWidgetsFlutterBinding;
 
   /// Renders the UI from the given [widget].
   ///
@@ -485,9 +485,10 @@ class WidgetTester extends WidgetController implements HitTestDispatcher, Ticker
   @override
   void dispatchEvent(PointerEvent event, HitTestResult result) {
     if (event is PointerDownEvent) {
-      final RenderObject innerTarget = result.path.firstWhere(
-        (HitTestEntry candidate) => candidate.target is RenderObject,
-      ).target;
+      final RenderObject innerTarget = result.path
+        .map((HitTestEntry candidate) => candidate.target)
+        .whereType<RenderObject>()
+        .first;
       final Element innerTargetElement = collectAllElementsFrom(
         binding.renderViewElement,
         skipOffstage: true,
@@ -515,8 +516,8 @@ class WidgetTester extends WidgetController implements HitTestDispatcher, Ticker
           break;
         totalNumber += 1; // optimistically assume we'll be able to describe it
 
-        if (element.widget is Tooltip) {
-          final Tooltip widget = element.widget;
+        final Widget widget = element.widget;
+        if (widget is Tooltip) {
           final Iterable<Element> matches = find.byTooltip(widget.message).evaluate();
           if (matches.length == 1) {
             debugPrint('  find.byTooltip(\'${widget.message}\')');
@@ -524,9 +525,8 @@ class WidgetTester extends WidgetController implements HitTestDispatcher, Ticker
           }
         }
 
-        if (element.widget is Text) {
+        if (widget is Text) {
           assert(descendantText == null);
-          final Text widget = element.widget;
           final Iterable<Element> matches = find.text(widget.data).evaluate();
           descendantText = widget.data;
           if (matches.length == 1) {
@@ -535,13 +535,13 @@ class WidgetTester extends WidgetController implements HitTestDispatcher, Ticker
           }
         }
 
-        if (element.widget.key is ValueKey<dynamic>) {
-          final ValueKey<dynamic> key = element.widget.key;
+        final Key key = widget.key;
+        if (key is ValueKey<dynamic>) {
           String keyLabel;
           if (key is ValueKey<int> ||
               key is ValueKey<double> ||
               key is ValueKey<bool>) {
-            keyLabel = 'const ${element.widget.key.runtimeType}(${key.value})';
+            keyLabel = 'const ${key.runtimeType}(${key.value})';
           } else if (key is ValueKey<String>) {
             keyLabel = 'const Key(\'${key.value}\')';
           }
@@ -554,20 +554,20 @@ class WidgetTester extends WidgetController implements HitTestDispatcher, Ticker
           }
         }
 
-        if (!_isPrivate(element.widget.runtimeType)) {
+        if (!_isPrivate(widget.runtimeType)) {
           if (numberOfTypes < 5) {
-            final Iterable<Element> matches = find.byType(element.widget.runtimeType).evaluate();
+            final Iterable<Element> matches = find.byType(widget.runtimeType).evaluate();
             if (matches.length == 1) {
-              debugPrint('  find.byType(${element.widget.runtimeType})');
+              debugPrint('  find.byType(${widget.runtimeType})');
               numberOfTypes += 1;
               continue;
             }
           }
 
           if (descendantText != null && numberOfWithTexts < 5) {
-            final Iterable<Element> matches = find.widgetWithText(element.widget.runtimeType, descendantText).evaluate();
+            final Iterable<Element> matches = find.widgetWithText(widget.runtimeType, descendantText).evaluate();
             if (matches.length == 1) {
-              debugPrint('  find.widgetWithText(${element.widget.runtimeType}, \'$descendantText\')');
+              debugPrint('  find.widgetWithText(${widget.runtimeType}, \'$descendantText\')');
               numberOfWithTexts += 1;
               continue;
             }
@@ -842,7 +842,7 @@ class WidgetTester extends WidgetController implements HitTestDispatcher, Ticker
     RenderObject renderObject = element.findRenderObject();
     SemanticsNode result = renderObject.debugSemantics;
     while (renderObject != null && result == null) {
-      renderObject = renderObject?.parent;
+      renderObject = renderObject?.parent as RenderObject;
       result = renderObject?.debugSemantics;
     }
     if (result == null)

packages/flutter_test/test/finders_test.dart

@@ -128,7 +128,7 @@ void main() {
     final Text text = find.descendant(
       of: find.byKey(key1),
       matching: find.byType(Text),
-    ).last.evaluate().single.widget;
+    ).last.evaluate().single.widget as Text;
 
     expect(text.data, '1');
   });

packages/flutter_test/test/goldens_test.dart

@@ -77,7 +77,7 @@ void main() {
     test('is initialized by test framework', () {
       expect(goldenFileComparator, isNotNull);
       expect(goldenFileComparator, isInstanceOf<LocalFileComparator>());
-      final LocalFileComparator comparator = goldenFileComparator;
+      final LocalFileComparator comparator = goldenFileComparator as LocalFileComparator;
       expect(comparator.basedir.path, contains('flutter_test'));
     });
   });

packages/flutter_test/test/test_async_utils_test.dart

@@ -159,7 +159,7 @@ void main() {
       real_test.expect(information[3], isInstanceOf<DiagnosticsProperty<void>>());
       real_test.expect(information[4], isInstanceOf<DiagnosticsProperty<void>>());
       real_test.expect(information[5], isInstanceOf<DiagnosticsStackTrace>());
-      final DiagnosticsStackTrace stackTraceProperty = information[5];
+      final DiagnosticsStackTrace stackTraceProperty = information[5] as DiagnosticsStackTrace;
       real_test.expect(stackTraceProperty.name, '\nWhen the first method was called, this was the stack');
       real_test.expect(stackTraceProperty.value, isInstanceOf<StackTrace>());
     }

packages/flutter_test/test/test_config/config_test_utils.dart

@@ -11,7 +11,7 @@ void testConfig(
   String expectedStringValue, {
   Map<Type, dynamic> otherExpectedValues = const <Type, dynamic>{int: isNull},
 }) {
-  final String actualStringValue = Zone.current[String];
+  final String actualStringValue = Zone.current[String] as String;
   final Map<Type, dynamic> otherActualValues = otherExpectedValues.map<Type, dynamic>(
     (Type key, dynamic value) {
       return MapEntry<Type, dynamic>(key, Zone.current[key]);

packages/flutter_test/test/widget_tester_test.dart

@@ -193,7 +193,7 @@ void main() {
       TestFailure failure;
       try {
         expect(find.text('foo', skipOffstage: false), findsOneWidget);
-      } catch (e) {
+      } on TestFailure catch (e) {
         failure = e;
       }
 
@@ -216,7 +216,7 @@ void main() {
       TestFailure failure;
       try {
         expect(find.text('foo', skipOffstage: false), findsNothing);
-      } catch (e) {
+      } on TestFailure catch (e) {
         failure = e;
       }
 
@@ -234,7 +234,7 @@ void main() {
       TestFailure failure;
       try {
         expect(find.text('foo'), findsNothing);
-      } catch (e) {
+      } on TestFailure catch (e) {
         failure = e;
       }
 
@@ -289,7 +289,7 @@ void main() {
       TestFailure failure;
       try {
         expect(find.byElementPredicate((_) => false, description: customDescription), findsOneWidget);
-      } catch (e) {
+      } on TestFailure catch (e) {
         failure = e;
       }
 
@@ -306,7 +306,7 @@ void main() {
       TestFailure failure;
       try {
         expect(find.byWidgetPredicate((_) => false, description: customDescription), findsOneWidget);
-      } catch (e) {
+      } on TestFailure catch (e) {
         failure = e;
       }
 
@@ -360,7 +360,7 @@ void main() {
           of: find.widgetWithText(Column, 'foo'),
           matching: find.text('bar'),
         ), findsOneWidget);
-      } catch (e) {
+      } on TestFailure catch (e) {
         failure = e;
       }
 
@@ -422,7 +422,7 @@ void main() {
           of: find.text('bar'),
           matching: find.widgetWithText(Column, 'foo'),
         ), findsOneWidget);
-      } catch (e) {
+      } on TestFailure catch (e) {
         failure = e;
       }
 

packages/flutter_test/test/window_test.dart

@@ -224,7 +224,7 @@ void verifyThatTestWindowCanFakeProperty<WindowPropertyType>({
 TestWidgetsFlutterBinding retrieveTestBinding(WidgetTester tester) {
   final WidgetsBinding binding = tester.binding;
   assert(binding is TestWidgetsFlutterBinding);
-  final TestWidgetsFlutterBinding testBinding = binding;
+  final TestWidgetsFlutterBinding testBinding = binding as TestWidgetsFlutterBinding;
   return testBinding;
 }