add parser parseAsync flag

pkg/analyzer/test/generated/parser_test.dart

 // Copyright (c) 2014, 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 analyzer.test.generated.parser_test;
 
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/src/dart/element/element.dart';
 import 'package:analyzer/src/generated/ast.dart';
@@ skipping 919 matching lines @@
         [ParserErrorCode.DUPLICATED_MODIFIER]);
   }
 
   void test_duplicateLabelInSwitchStatement() {
     parse4(
         "parseSwitchStatement",
         "switch (e) {l1: case 0: break; l1: case 1: break;}",
         [ParserErrorCode.DUPLICATE_LABEL_IN_SWITCH_STATEMENT]);
   }
 
+  void test_enableAsync_false_1() {
+    parseAsync = false;
+    parse4("parseFunctionDeclarationStatement",
+        "foo() async {}", [ParserErrorCode.ASYNC_NOT_SUPPORTED]);
+  }
+
+  void test_enableAsync_false_2() {
+    parseAsync = false;
+    parse4("parseFunctionDeclarationStatement",
+        "foo() sync* {}", [ParserErrorCode.ASYNC_NOT_SUPPORTED]);
+  }
+
   void test_emptyEnumBody() {
     parse3("parseEnumDeclaration", <Object>[emptyCommentAndMetadata()],
         "enum E {}", [ParserErrorCode.EMPTY_ENUM_BODY]);
   }
 
   void test_enumInClass() {
     ParserTestCase.parseCompilationUnit(
         r'''
 class Foo {
   enum Bar {
@@ skipping 1690 matching lines @@
    * An empty list of objects used as arguments to zero-argument methods.
    */
   static const List<Object> _EMPTY_ARGUMENTS = const <Object>[];
 
   /**
    * A flag indicating whether parser is to parse function bodies.
    */
   static bool parseFunctionBodies = true;
 
   /**
+   * A flag indicating whether parser is to parse async.
+   */
+  bool parseAsync = true;
+
+  /**
    * A flag indicating whether conditional directives support should be enabled
    * for a specific test.
    */
   bool enableConditionalDirectives = false;
 
   /**
    * A flag indicating whether generic method support should be enabled for a
    * specific test.
    */
   bool enableGenericMethods = false;
@@ skipping 46 matching lines @@
     //
     Scanner scanner =
         new Scanner(null, new CharSequenceReader(source), listener);
     scanner.scanGenericMethodComments = enableGenericMethodComments;
     Token tokenStream = scanner.tokenize();
     listener.setLineInfo(new TestSource(), scanner.lineStarts);
     //
     // Parse the source.
     //
     Parser parser = createParser(listener);
+    parser.parseAsync = parseAsync;
     parser.parseConditionalDirectives = enableConditionalDirectives;
     parser.parseGenericMethods = enableGenericMethods;
     parser.parseGenericMethodComments = enableGenericMethodComments;
     parser.parseFunctionBodies = parseFunctionBodies;
     Object result =
         invokeParserMethodImpl(parser, methodName, objects, tokenStream);
     //
     // Partially test the results.
     //
     if (!listener.hasErrors) {
@@ skipping 8644 matching lines @@
         new Scanner(null, new CharSequenceReader(source), listener);
     Token tokenStream = scanner.tokenize();
     //
     // Parse the source.
     //
     Parser parser = new Parser(null, listener);
     return invokeParserMethodImpl(
         parser, methodName, <Object>[tokenStream], tokenStream) as Token;
   }
 }