Track async state in parser.

pkg/compiler/lib/src/elements/elements.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library elements;
 
+import 'package:front_end/src/fasta/parser/async_modifier.dart'
+    show AsyncModifier;
+
 import '../common.dart';
 import '../common/resolution.dart' show Resolution;
 import '../constants/constructors.dart';
 import '../constants/expressions.dart';
 import '../common_elements.dart' show CommonElements;
 import '../ordered_typeset.dart' show OrderedTypeSet;
 import '../resolution/scope.dart' show Scope;
 import '../resolution/tree_elements.dart' show TreeElements;
 import '../script.dart';
 import 'package:front_end/src/fasta/scanner.dart'
     show Token, isUserDefinableOperator, isMinusOperator;
-import '../tree/tree.dart';
+import '../tree/tree.dart' hide AsyncModifier;
 import '../universe/call_structure.dart';
 import 'package:front_end/src/fasta/scanner/characters.dart' show $_;
 import '../util/util.dart';
 import '../world.dart' show ClosedWorld;
 import 'entities.dart';
 import 'resolution_types.dart';
 import 'visitor.dart' show ElementVisitor;
 
 part 'names.dart';
 
@@ skipping 1301 matching lines @@
 
 /// A setter.
 abstract class SetterElement extends AccessorElement {
   /// The getter corresponding to this setter, if any.
   GetterElement get getter;
 }
 
 /// Enum for the synchronous/asynchronous function body modifiers.
 class AsyncMarker {
   /// The default function body marker.
-  static const AsyncMarker SYNC = const AsyncMarker._();
+  static const AsyncMarker SYNC = const AsyncMarker._(AsyncModifier.Sync);
 
   /// The `sync*` function body marker.
-  static const AsyncMarker SYNC_STAR = const AsyncMarker._(isYielding: true);
+  static const AsyncMarker SYNC_STAR =
+      const AsyncMarker._(AsyncModifier.SyncStar, isYielding: true);
 
   /// The `async` function body marker.
-  static const AsyncMarker ASYNC = const AsyncMarker._(isAsync: true);
+  static const AsyncMarker ASYNC =
+      const AsyncMarker._(AsyncModifier.Async, isAsync: true);
 
   /// The `async*` function body marker.
-  static const AsyncMarker ASYNC_STAR =
-      const AsyncMarker._(isAsync: true, isYielding: true);
+  static const AsyncMarker ASYNC_STAR = const AsyncMarker._(
+      AsyncModifier.AsyncStar,
+      isAsync: true,
+      isYielding: true);
 
   /// Is `true` if this marker defines the function body to have an
   /// asynchronous result, that is, either a [Future] or a [Stream].
   final bool isAsync;
 
   /// Is `true` if this marker defines the function body to have a plural
   /// result, that is, either an [Iterable] or a [Stream].
   final bool isYielding;
 
-  const AsyncMarker._({this.isAsync: false, this.isYielding: false});
+  final AsyncModifier asyncParserState;
+
+  const AsyncMarker._(this.asyncParserState,
+      {this.isAsync: false, this.isYielding: false});
 
   String toString() {
     return '${isAsync ? 'async' : 'sync'}${isYielding ? '*' : ''}';
   }
 
   /// Canonical list of marker values.
   ///
   /// Added to make [AsyncMarker] enum-like.
   static const List<AsyncMarker> values = const <AsyncMarker>[
     SYNC,
@@ skipping 646 matching lines @@
   /// by a field.
   bool get isDeclaredByField;
 
   /// Returns `true` if this member is abstract.
   bool get isAbstract;
 
   /// If abstract, [implementation] points to the overridden concrete member,
   /// if any. Otherwise [implementation] points to the member itself.
   Member get implementation;
 }