Merge pull request #3333 from pq/optional_type_args

Adding `@optionalTypeArgs`.

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

@@ -10,6 +10,7 @@ import 'debug.dart';
 
 import 'package:flutter/rendering.dart';
 import 'package:flutter/services.dart';
+import 'package:meta/meta.dart';
 
 export 'dart:ui' show hashValues, hashList;
 export 'package:flutter/rendering.dart' show RenderObject, RenderBox, debugPrint;
@@ -112,6 +113,7 @@ typedef void GlobalKeyRemoveListener(GlobalKey key);
 /// GlobalKeys are relatively expensive. If you don't need any of the features
 /// listed above, consider using a [Key], [ValueKey], [ObjectKey], or
 /// [UniqueKey] instead.
+@optionalTypeArgs
 abstract class GlobalKey<T extends State<StatefulWidget>> extends Key {
   /// Constructs a LabeledGlobalKey, which is a GlobalKey with a label used for debugging.
   /// The label is not used for comparing the identity of the key.
@@ -253,6 +255,7 @@ class GlobalObjectKey extends GlobalKey {
 }
 
 /// This class is a work-around for the "is" operator not accepting a variable value as its right operand
+@optionalTypeArgs
 class TypeMatcher<T> {
   const TypeMatcher();
   bool check(dynamic object) => object is T;
@@ -346,6 +349,7 @@ enum _StateLifecycle {
 typedef void StateSetter(VoidCallback fn);
 
 /// The logic and internal state for a [StatefulWidget].
+@optionalTypeArgs
 abstract class State<T extends StatefulWidget> {
   /// The current configuration (an instance of the corresponding
   /// [StatefulWidget] class).

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

@@ -8,6 +8,7 @@ import 'dart:ui' as ui show window;
 
 import 'package:newton/newton.dart';
 import 'package:flutter/gestures.dart';
+import 'package:meta/meta.dart';
 
 import 'basic.dart';
 import 'framework.dart';
@@ -217,6 +218,7 @@ abstract class Scrollable extends StatefulWidget {
 /// along the [config.scrollDirection] axis and are implemented in
 /// terms of the [pixelOffsetToScrollOffset] and
 /// [scrollOffsetToPixelOffset] methods.
+@optionalTypeArgs
 abstract class ScrollableState<T extends Scrollable> extends State<T> {
   @override
   void initState() {

packages/flutter/pubspec.yaml

@@ -12,6 +12,8 @@ dependencies:
   # We need to pin crypto because archive can't handle larger numbers.
   crypto: 0.9.2
 
+  meta: ^0.12.0
+
   sky_engine:
     path: ../../bin/cache/pkg/sky_engine
   sky_services:

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

@@ -357,7 +357,6 @@ class AnalyzeCommand extends FlutterCommand {
     ];
 
     RegExp generalPattern = new RegExp(r'^\[(error|warning|hint|lint)\] (.+) \(([^(),]+), line ([0-9]+), col ([0-9]+)\)$');
-    RegExp classesWithOptionalTypeArgumentsPattern = new RegExp(r'\b(GlobalKey|State|ScrollableState|Element|StatelessElement|TypeMatcher)\b');
     RegExp conflictingNamesPattern = new RegExp('^The imported libraries \'([^\']+)\' and \'([^\']+)\' cannot have the same name \'([^\']+)\'\$');
     RegExp missingFilePattern = new RegExp('^Target of URI does not exist: \'([^\')]+)\'\$');
     RegExp documentAllMembersPattern = new RegExp('^Document all public members\$');
@@ -419,11 +418,6 @@ class AnalyzeCommand extends FlutterCommand {
           } else if (sourceLines.first.startsWith('// DO NOT EDIT. This is code generated')) {
             // autogenerated code - TODO(ianh): Fix the intl package resource generator
             shouldIgnore = true;
-          } else if (level == 'lint' && errorMessage == 'Specify type annotations.') {
-            // we want the type annotations on certain classes to be optional.
-            // see https://github.com/dart-lang/linter/issues/196
-            if (classesWithOptionalTypeArgumentsPattern.matchAsPrefix(sourceLine, colNumber-1) != null)
-              shouldIgnore = true;
           }
           if (shouldIgnore)
             continue;