Add FunctionEntity.asyncMarker and refactor SourceInformationStrategy to avoid ResolvedAst

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'
@@ skipping 1315 matching lines @@
   /// The setter corresponding to this getter, if any.
   SetterElement get setter;
 }
 
 /// 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._(AsyncModifier.Sync);
-
-  /// The `sync*` function body marker.
-  static const AsyncMarker SYNC_STAR =
-      const AsyncMarker._(AsyncModifier.SyncStar, isYielding: true);
-
-  /// The `async` function body marker.
-  static const AsyncMarker ASYNC =
-      const AsyncMarker._(AsyncModifier.Async, isAsync: true);
-
-  /// The `async*` function body marker.
-  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;
-
-  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,
-    SYNC_STAR,
-    ASYNC,
-    ASYNC_STAR
-  ];
-
-  /// Index to this marker within [values].
-  ///
-  /// Added to make [AsyncMarker] enum-like.
-  int get index => values.indexOf(this);
-}
-
 /// A top level, static or instance function.
 abstract class MethodElement extends FunctionElement
     implements MemberElement, FunctionEntity {}
 
 /// A local function or closure (anonymous local function).
 abstract class LocalFunctionElement extends FunctionElement
     implements LocalElement {}
 
 /// A constructor.
 abstract class ConstructorElement extends MethodElement
@@ skipping 625 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;
 }