Replace @checked with covariant (#8300)

Fixes #7734

examples/flutter_gallery/lib/demo/shrine/shrine_home.dart

@@ -111,7 +111,7 @@ class ShrineGridDelegate extends SliverGridDelegate {
   }
 
   @override
-  bool shouldRelayout(@checked SliverGridDelegate oldDelegate) => false;
+  bool shouldRelayout(covariant SliverGridDelegate oldDelegate) => false;
 }
 
 /// Displays the Vendor's name and avatar.

packages/flutter/lib/foundation.dart

@@ -21,7 +21,6 @@ export 'src/foundation/print.dart';
 export 'src/foundation/synchronous_future.dart';
 
 export 'package:meta/meta.dart' show
-  checked,
   mustCallSuper,
   optionalTypeArgs,
   protected,

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

@@ -552,7 +552,7 @@ class _SliverAppBarDelegate extends SliverPersistentHeaderDelegate {
   }
 
   @override
-  bool shouldRebuild(@checked _SliverAppBarDelegate oldDelegate) {
+  bool shouldRebuild(covariant _SliverAppBarDelegate oldDelegate) {
     return leading != oldDelegate.leading
         || title != oldDelegate.title
         || actions != oldDelegate.actions

packages/flutter/lib/src/rendering/box.dart

@@ -958,7 +958,7 @@ class _IntrinsicDimensionsCacheEntry {
 /// these classes, however, you must implement the algorithm yourself.
 abstract class RenderBox extends RenderObject {
   @override
-  void setupParentData(@checked RenderObject child) {
+  void setupParentData(covariant RenderObject child) {
     if (child.parentData is! BoxParentData)
       child.parentData = new BoxParentData();
   }
@@ -1863,7 +1863,7 @@ abstract class RenderBox extends RenderObject {
   /// ```
   // TODO(ianh): Fix the type of the argument here once https://github.com/dart-lang/sdk/issues/25232 is fixed
   @override
-  void handleEvent(PointerEvent event, @checked HitTestEntry entry) {
+  void handleEvent(PointerEvent event, covariant HitTestEntry entry) {
     super.handleEvent(event, entry);
   }
 

packages/flutter/lib/src/rendering/custom_layout.dart

@@ -243,7 +243,7 @@ abstract class MultiChildLayoutDelegate {
   /// This should compare the fields of the current delegate and the given
   /// `oldDelegate` and return true if the fields are such that the layout would
   /// be different.
-  bool shouldRelayout(@checked MultiChildLayoutDelegate oldDelegate);
+  bool shouldRelayout(covariant MultiChildLayoutDelegate oldDelegate);
 
   /// Override this method to include additional information in the
   /// debugging data printed by [debugDumpRenderTree] and friends.

packages/flutter/lib/src/rendering/flow.dart

@@ -108,7 +108,7 @@ abstract class FlowDelegate {
   /// This should compare the fields of the current delegate and the given
   /// oldDelegate and return true if the fields are such that the layout would
   /// be different.
-  bool shouldRelayout(@checked FlowDelegate oldDelegate) => false;
+  bool shouldRelayout(covariant FlowDelegate oldDelegate) => false;
 
   /// Override this method to return true when the children need to be
   /// repainted. This should compare the fields of the current delegate and the
@@ -123,7 +123,7 @@ abstract class FlowDelegate {
   /// The flow container might repaint even if this function returns false, for
   /// example if layout triggers painting (e.g., if [shouldRelayout] returns
   /// true).
-  bool shouldRepaint(@checked FlowDelegate oldDelegate);
+  bool shouldRepaint(covariant FlowDelegate oldDelegate);
 
   /// Override this method to include additional information in the
   /// debugging data printed by [debugDumpRenderTree] and friends.

packages/flutter/lib/src/rendering/node.dart

@@ -83,7 +83,7 @@ class AbstractNode {
   /// Subclasses with children should [attach] all their children to the same
   /// [owner] whenever this method is called.
   @mustCallSuper
-  void attach(@checked Object owner) {
+  void attach(covariant Object owner) {
     assert(owner != null);
     assert(_owner == null);
     _owner = owner;
@@ -111,7 +111,7 @@ class AbstractNode {
   /// Subclasses should call this function when they acquire a new child.
   @protected
   @mustCallSuper
-  void adoptChild(@checked AbstractNode child) {
+  void adoptChild(covariant AbstractNode child) {
     assert(child != null);
     assert(child._parent == null);
     assert(() {
@@ -132,7 +132,7 @@ class AbstractNode {
   /// Subclasses should call this function when they lose a child.
   @protected
   @mustCallSuper
-  void dropChild(@checked AbstractNode child) {
+  void dropChild(covariant AbstractNode child) {
     assert(child != null);
     assert(child._parent == this);
     assert(child.attached == attached);

packages/flutter/lib/src/rendering/object.dart

@@ -1255,7 +1255,7 @@ abstract class RenderObject extends AbstractNode implements HitTestTarget {
   ///
   /// You can call this function to set up the parent data for child before the
   /// child is added to the parent's child list.
-  void setupParentData(@checked RenderObject child) {
+  void setupParentData(covariant RenderObject child) {
     assert(_debugCanPerformMutations);
     if (child.parentData is! ParentData)
       child.parentData = new ParentData();
@@ -2143,7 +2143,7 @@ abstract class RenderObject extends AbstractNode implements HitTestTarget {
   ///
   /// Used by coordinate conversion functions to translate coordinates local to
   /// one render object into coordinates local to another render object.
-  void applyPaintTransform(@checked RenderObject child, Matrix4 transform) {
+  void applyPaintTransform(covariant RenderObject child, Matrix4 transform) {
     assert(child.parent == this);
   }
 
@@ -2155,7 +2155,7 @@ abstract class RenderObject extends AbstractNode implements HitTestTarget {
   ///
   /// This is used in the semantics phase to avoid including children
   /// that are not physically visible.
-  Rect describeApproximatePaintClip(@checked RenderObject child) => null;
+  Rect describeApproximatePaintClip(covariant RenderObject child) => null;
 
 
   // SEMANTICS
@@ -2383,7 +2383,7 @@ abstract class RenderObject extends AbstractNode implements HitTestTarget {
 
   /// Override this method to handle pointer events that hit this render object.
   @override
-  void handleEvent(PointerEvent event, @checked HitTestEntry entry) { }
+  void handleEvent(PointerEvent event, covariant HitTestEntry entry) { }
 
 
   // HIT TESTING

packages/flutter/lib/src/rendering/proxy_box.dart

@@ -918,7 +918,7 @@ abstract class CustomClipper<T> {
   /// It's possible that the [getClip] method will get called even if
   /// [shouldReclip] returns false or if the [shouldReclip] method is never
   /// called at all (e.g. if the box changes size).
-  bool shouldReclip(@checked CustomClipper<T> oldClipper);
+  bool shouldReclip(covariant CustomClipper<T> oldClipper);
 }
 
 abstract class _RenderCustomClip<T> extends RenderProxyBox {
@@ -1761,7 +1761,7 @@ abstract class CustomPainter {
   /// repaints should be avoided as much as possible, a [RepaintBoundary] or
   /// [RenderRepaintBoundary] (or other render object with [isRepaintBoundary]
   /// set to true) might be helpful.
-  bool shouldRepaint(@checked CustomPainter oldDelegate);
+  bool shouldRepaint(covariant CustomPainter oldDelegate);
 
   /// Called whenever a hit test is being performed on an object that is using
   /// this custom paint delegate.

packages/flutter/lib/src/rendering/shifted_box.dart

@@ -4,8 +4,6 @@
 
 import 'dart:math' as math;
 
-import 'package:flutter/foundation.dart';
-
 import 'box.dart';
 import 'debug.dart';
 import 'object.dart';
@@ -748,7 +746,7 @@ abstract class SingleChildLayoutDelegate {
   /// It's also possible that the layout method will get called
   /// without [shouldRelayout] being called at all (e.g. if the parent changes
   /// size).
-  bool shouldRelayout(@checked SingleChildLayoutDelegate oldDelegate);
+  bool shouldRelayout(covariant SingleChildLayoutDelegate oldDelegate);
 }
 
 /// Defers the layout of its single child to a delegate.

packages/flutter/lib/src/rendering/sliver.dart

@@ -913,7 +913,7 @@ abstract class RenderSliver extends RenderObject {
   /// of the sliver whereas [childScrollOffset] gives the distance from sliver's
   /// zero scroll offset.
   @protected
-  double childMainAxisPosition(@checked RenderObject child) {
+  double childMainAxisPosition(covariant RenderObject child) {
     assert(() {
       throw new FlutterError('$runtimeType does not implement childPosition.');
     });
@@ -931,7 +931,7 @@ abstract class RenderSliver extends RenderObject {
   ///
   /// Calling this for a child that is not visible is not valid.
   @protected
-  double childCrossAxisPosition(@checked RenderObject child) => 0.0;
+  double childCrossAxisPosition(covariant RenderObject child) => 0.0;
 
   /// Returns the scroll offset for the leading edge of the given child.
   ///
@@ -941,7 +941,7 @@ abstract class RenderSliver extends RenderObject {
   /// [childMainAxisPosition] gives the distance from the leading _visible_ edge
   /// of the sliver whereas [childScrollOffset] gives the distance from sliver's
   /// zero scroll offset.
-  double childScrollOffset(@checked RenderObject child) {
+  double childScrollOffset(covariant RenderObject child) {
     assert(child.parent == this);
     return 0.0;
   }

packages/flutter/lib/src/rendering/sliver_grid.dart

@@ -227,7 +227,7 @@ abstract class SliverGridDelegate {
   /// Returns information about the size and position of the tiles in the grid.
   SliverGridLayout getLayout(SliverConstraints constraints);
 
-  bool shouldRelayout(@checked SliverGridDelegate oldDelegate);
+  bool shouldRelayout(covariant SliverGridDelegate oldDelegate);
 }
 
 /// Creates grid layouts with a fixed number of tiles in the cross axis.

packages/flutter/lib/src/rendering/sliver_persistent_header.dart

@@ -133,7 +133,7 @@ abstract class RenderSliverPersistentHeader extends RenderSliver with RenderObje
   ///
   /// If there is no child, this should return 0.0.
   @override
-  double childMainAxisPosition(@checked RenderObject child) => super.childMainAxisPosition(child);
+  double childMainAxisPosition(covariant RenderObject child) => super.childMainAxisPosition(child);
 
   @override
   bool hitTestChildren(HitTestResult result, { @required double mainAxisPosition, @required double crossAxisPosition }) {

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

@@ -1860,7 +1860,7 @@ class Flex extends MultiChildRenderObjectWidget {
   }
 
   @override
-  void updateRenderObject(BuildContext context, @checked RenderFlex renderObject) {
+  void updateRenderObject(BuildContext context, covariant RenderFlex renderObject) {
     renderObject
       ..direction = direction
       ..mainAxisAlignment = mainAxisAlignment

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

@@ -824,7 +824,7 @@ abstract class State<T extends StatefulWidget> {
   /// super.didUpdateConfig(oldConfig).
   // TODO(abarth): Add @mustCallSuper.
   @protected
-  void didUpdateConfig(@checked T oldConfig) { }
+  void didUpdateConfig(covariant T oldConfig) { }
 
   /// Called whenever the application is reassembled during debugging.
   ///
@@ -1189,7 +1189,7 @@ abstract class InheritedWidget extends ProxyWidget {
   /// The given widget is guaranteed to have the same [runtimeType] as this
   /// object.
   @protected
-  bool updateShouldNotify(@checked InheritedWidget oldWidget);
+  bool updateShouldNotify(covariant InheritedWidget oldWidget);
 }
 
 /// RenderObjectWidgets provide the configuration for [RenderObjectElement]s,
@@ -1226,13 +1226,13 @@ abstract class RenderObjectWidget extends Widget {
   /// [createElement] method. See, for example,
   /// [SingleChildRenderObjectElement.update].
   @protected
-  void updateRenderObject(BuildContext context, @checked RenderObject renderObject) { }
+  void updateRenderObject(BuildContext context, covariant RenderObject renderObject) { }
 
   /// A render object previously associated with this widget has been removed
   /// from the tree. The given [RenderObject] will be of the same type as
   /// returned by this object's [createRenderObject].
   @protected
-  void didUnmountRenderObject(@checked RenderObject renderObject) { }
+  void didUnmountRenderObject(covariant RenderObject renderObject) { }
 }
 
 /// A superclass for RenderObjectWidgets that configure RenderObject subclasses
@@ -2141,7 +2141,7 @@ abstract class Element implements BuildContext {
   ///
   /// This function is called only during the "active" lifecycle state.
   @mustCallSuper
-  void update(@checked Widget newWidget) {
+  void update(covariant Widget newWidget) {
     // This code is hot when hot reloading, so we try to
     // only call _AssertionError._evaluateAssertion once.
     assert(_debugLifecycleState == _ElementLifecycle.active
@@ -3159,7 +3159,7 @@ abstract class ProxyElement extends ComponentElement {
   /// Called during [update] after changing the widget associated with this
   /// element but before rebuilding this element.
   @protected
-  void notifyClients(@checked ProxyWidget oldWidget);
+  void notifyClients(covariant ProxyWidget oldWidget);
 }
 
 /// An [Element] that uses a [ParentDataWidget] as its configuration.
@@ -3483,7 +3483,7 @@ abstract class RenderObjectElement extends BuildableElement {
   }
 
   @override
-  void update(@checked RenderObjectWidget newWidget) {
+  void update(covariant RenderObjectWidget newWidget) {
     super.update(newWidget);
     assert(widget == newWidget);
     assert(() { _debugUpdateRenderObjectOwner(); return true; });
@@ -3729,7 +3729,7 @@ abstract class RenderObjectElement extends BuildableElement {
   /// element has a list of children, the previous sibling is a convenient value
   /// for the slot.
   @protected
-  void insertChildRenderObject(@checked RenderObject child, @checked dynamic slot);
+  void insertChildRenderObject(covariant RenderObject child, covariant dynamic slot);
 
   /// Move the given child to the given slot.
   ///
@@ -3740,13 +3740,13 @@ abstract class RenderObjectElement extends BuildableElement {
   /// element has a list of children, the previous sibling is a convenient value
   /// for the slot.
   @protected
-  void moveChildRenderObject(@checked RenderObject child, @checked dynamic slot);
+  void moveChildRenderObject(covariant RenderObject child, covariant dynamic slot);
 
   /// Remove the given child from [renderObject].
   ///
   /// The given child is guaranteed to have [renderObject] as its parent.
   @protected
-  void removeChildRenderObject(@checked RenderObject child);
+  void removeChildRenderObject(covariant RenderObject child);
 
   @override
   void debugFillDescription(List<String> description) {

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

@@ -53,7 +53,7 @@ class ScrollBehavior {
     return null;
   }
 
-  bool shouldNotify(@checked ScrollBehavior oldDelegate) => false;
+  bool shouldNotify(covariant ScrollBehavior oldDelegate) => false;
 }
 
 class ScrollConfiguration extends InheritedWidget {

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

@@ -38,7 +38,7 @@ abstract class SliverChildDelegate {
     double trailingScrollOffset,
   ) => null;
 
-  bool shouldRebuild(@checked SliverChildDelegate oldDelegate);
+  bool shouldRebuild(covariant SliverChildDelegate oldDelegate);
 
   @override
   String toString() {
@@ -81,7 +81,7 @@ class SliverChildBuilderDelegate extends SliverChildDelegate {
   int get estimatedChildCount => childCount;
 
   @override
-  bool shouldRebuild(@checked SliverChildBuilderDelegate oldDelegate) => true;
+  bool shouldRebuild(covariant SliverChildBuilderDelegate oldDelegate) => true;
 }
 
 // ///
@@ -127,7 +127,7 @@ class SliverChildListDelegate extends SliverChildDelegate {
   int get estimatedChildCount => children.length;
 
   @override
-  bool shouldRebuild(@checked SliverChildListDelegate oldDelegate) {
+  bool shouldRebuild(covariant SliverChildListDelegate oldDelegate) {
     return children != oldDelegate.children;
   }
 }
@@ -427,7 +427,7 @@ class SliverMultiBoxAdaptorElement extends RenderObjectElement implements Render
   }
 
   @override
-  void insertChildRenderObject(@checked RenderObject child, int slot) {
+  void insertChildRenderObject(covariant RenderObject child, int slot) {
     assert(slot != null);
     assert(_currentlyUpdatingChildIndex == slot);
     renderObject.insert(child, after: _currentBeforeChild);
@@ -439,14 +439,14 @@ class SliverMultiBoxAdaptorElement extends RenderObjectElement implements Render
   }
 
   @override
-  void moveChildRenderObject(@checked RenderObject child, int slot) {
+  void moveChildRenderObject(covariant RenderObject child, int slot) {
     // TODO(ianh): At some point we should be better about noticing when a
     // particular LocalKey changes slot, and handle moving the nodes around.
     assert(false);
   }
 
   @override
-  void removeChildRenderObject(@checked RenderObject child) {
+  void removeChildRenderObject(covariant RenderObject child) {
     assert(_currentlyUpdatingChildIndex != null);
     renderObject.remove(child);
   }

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

@@ -18,7 +18,7 @@ abstract class SliverPersistentHeaderDelegate {
 
   double get maxExtent;
 
-  bool shouldRebuild(@checked SliverPersistentHeaderDelegate oldDelegate);
+  bool shouldRebuild(covariant SliverPersistentHeaderDelegate oldDelegate);
 }
 
 class SliverPersistentHeader extends StatelessWidget {
@@ -116,17 +116,17 @@ class _SliverPersistentHeaderElement extends RenderObjectElement {
   }
 
   @override
-  void insertChildRenderObject(@checked RenderObject child, Null slot) {
+  void insertChildRenderObject(covariant RenderObject child, Null slot) {
     renderObject.child = child;
   }
 
   @override
-  void moveChildRenderObject(@checked RenderObject child, Null slot) {
+  void moveChildRenderObject(covariant RenderObject child, Null slot) {
     assert(false);
   }
 
   @override
-  void removeChildRenderObject(@checked RenderObject child) {
+  void removeChildRenderObject(covariant RenderObject child) {
     renderObject.child = null;
   }
 

packages/flutter/test/widgets/image_resolution_test.dart

@@ -11,7 +11,6 @@ import 'package:flutter/rendering.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:meta/meta.dart';
 
 class TestImage extends ui.Image {
   TestImage(this.scale);
@@ -97,7 +96,7 @@ class TestAssetImage extends AssetImage {
   }
 
   @override
-  Future<ui.Image> decodeImage(@checked TestByteData data) {
+  Future<ui.Image> decodeImage(covariant TestByteData data) {
     return new SynchronousFuture<ui.Image>(new TestImage(data.scale));
   }
 }

packages/flutter/test/widgets/routes_test.dart

@@ -6,7 +6,6 @@ import 'dart:collection';
 
 import 'package:flutter_test/flutter_test.dart';
 import 'package:flutter/widgets.dart';
-import 'package:meta/meta.dart';
 
 final List<String> results = <String>[];
 
@@ -45,7 +44,7 @@ class TestRoute extends LocalHistoryRoute<String> {
   }
 
   @override
-  void didReplace(@checked TestRoute oldRoute) {
+  void didReplace(covariant TestRoute oldRoute) {
     log('didReplace ${oldRoute.name}');
     super.didReplace(oldRoute);
   }
@@ -60,13 +59,13 @@ class TestRoute extends LocalHistoryRoute<String> {
   }
 
   @override
-  void didPopNext(@checked TestRoute nextRoute) {
+  void didPopNext(covariant TestRoute nextRoute) {
     log('didPopNext ${nextRoute.name}');
     super.didPopNext(nextRoute);
   }
 
   @override
-  void didChangeNext(@checked TestRoute nextRoute) {
+  void didChangeNext(covariant TestRoute nextRoute) {
     log('didChangeNext ${nextRoute?.name}');
     super.didChangeNext(nextRoute);
   }

packages/flutter/test/widgets/semantics_tester.dart

@@ -125,7 +125,7 @@ class _HasSemantics extends Matcher {
   final TestSemantics _semantics;
 
   @override
-  bool matches(@checked SemanticsTester item, Map<dynamic, dynamic> matchState) {
+  bool matches(covariant SemanticsTester item, Map<dynamic, dynamic> matchState) {
     return _semantics._matches(item.tester.binding.pipelineOwner.semanticsOwner.rootSemanticsNode, matchState);
   }
 

packages/flutter_markdown/lib/src/markdown_raw.dart

@@ -3,7 +3,6 @@
 // found in the LICENSE file.
 
 import 'package:markdown/markdown.dart' as md;
-import 'package:meta/meta.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter/gestures.dart';
 
@@ -67,7 +66,7 @@ class MarkdownRaw extends StatelessWidget {
 
   MarkdownBodyRaw createMarkdownBody({
     String data,
-    @checked MarkdownStyleRaw markdownStyle,
+    covariant MarkdownStyleRaw markdownStyle,
     SyntaxHighlighter syntaxHighlighter,
     MarkdownLinkCallback onTapLink
   }) {

packages/flutter_test/lib/src/binding.dart

@@ -847,7 +847,7 @@ class _LiveTestRenderView extends RenderView {
   @override
   TestViewConfiguration get configuration => super.configuration;
   @override
-  set configuration(@checked TestViewConfiguration value) { super.configuration = value; }
+  set configuration(covariant TestViewConfiguration value) { super.configuration = value; }
 
   final Map<int, _LiveTestPointerRecord> _pointers = <int, _LiveTestPointerRecord>{};
 

packages/flutter_test/lib/src/matchers.dart

@@ -4,7 +4,6 @@
 
 import 'package:flutter/material.dart';
 import 'package:test/test.dart';
-import 'package:meta/meta.dart';
 
 import 'finders.dart';
 
@@ -96,7 +95,7 @@ class _FindsWidgetMatcher extends Matcher {
   final int max;
 
   @override
-  bool matches(@checked Finder finder, Map<dynamic, dynamic> matchState) {
+  bool matches(covariant Finder finder, Map<dynamic, dynamic> matchState) {
     assert(min != null || max != null);
     assert(min == null || max == null || min <= max);
     matchState[Finder] = finder;
@@ -190,7 +189,7 @@ class _IsOffstage extends Matcher {
   const _IsOffstage();
 
   @override
-  bool matches(@checked Finder finder, Map<dynamic, dynamic> matchState) {
+  bool matches(covariant Finder finder, Map<dynamic, dynamic> matchState) {
     return _hasAncestorMatching(finder, (Widget widget) {
       if (widget is Offstage)
         return widget.offstage;
@@ -206,7 +205,7 @@ class _IsOnstage extends Matcher {
   const _IsOnstage();
 
   @override
-  bool matches(@checked Finder finder, Map<dynamic, dynamic> matchState) {
+  bool matches(covariant Finder finder, Map<dynamic, dynamic> matchState) {
     Iterable<Element> nodes = finder.evaluate();
     if (nodes.length != 1)
       return false;
@@ -230,7 +229,7 @@ class _IsInCard extends Matcher {
   const _IsInCard();
 
   @override
-  bool matches(@checked Finder finder, Map<dynamic, dynamic> matchState) => _hasAncestorOfType(finder, Card);
+  bool matches(covariant Finder finder, Map<dynamic, dynamic> matchState) => _hasAncestorOfType(finder, Card);
 
   @override
   Description describe(Description description) => description.add('in card');
@@ -240,7 +239,7 @@ class _IsNotInCard extends Matcher {
   const _IsNotInCard();
 
   @override
-  bool matches(@checked Finder finder, Map<dynamic, dynamic> matchState) => !_hasAncestorOfType(finder, Card);
+  bool matches(covariant Finder finder, Map<dynamic, dynamic> matchState) => !_hasAncestorOfType(finder, Card);
 
   @override
   Description describe(Description description) => description.add('not in card');