Add support for parsing, but not capturing, assers in constructor initializer lists

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/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/src/dart/ast/token.dart';
@@ skipping 2754 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 the parser is to parse asserts in the initializer
+   * list of a constructor.
+   */
+  bool enableAssertInitializer = false;
+
+  /**
    * A flag indicating whether parser is to parse async.
    */
   bool parseAsync = true;
 
   /**
    * A flag indicating whether generic method support should be enabled for a
    * specific test.
    */
   bool enableGenericMethods = false;
 
@@ skipping 52 matching lines @@
     Scanner scanner =
         new Scanner(null, new CharSequenceReader(source), listener);
     scanner.scanGenericMethodComments = enableGenericMethodComments;
     scanner.scanLazyAssignmentOperators = enableLazyAssignmentOperators;
     Token tokenStream = scanner.tokenize();
     listener.setLineInfo(new TestSource(), scanner.lineStarts);
     //
     // Parse the source.
     //
     Parser parser = createParser(listener);
+    parser.enableAssertInitializer = enableAssertInitializer;
     parser.parseAsync = parseAsync;
     parser.parseGenericMethods = enableGenericMethods;
     parser.parseGenericMethodComments = enableGenericMethodComments;
     parser.parseFunctionBodies = parseFunctionBodies;
     Object result =
         invokeParserMethodImpl(parser, methodName, objects, tokenStream);
     //
     // Partially test the results.
     //
     if (!listener.hasErrors) {
@@ skipping 109 matching lines @@
    * match those that are expected, or if the result would have been `null`.
    */
   CompilationUnit parseCompilationUnitWithOptions(String source,
       [List<ErrorCode> errorCodes = ErrorCode.EMPTY_LIST]) {
     GatheringErrorListener listener = new GatheringErrorListener();
     Scanner scanner =
         new Scanner(null, new CharSequenceReader(source), listener);
     listener.setLineInfo(new TestSource(), scanner.lineStarts);
     Token token = scanner.tokenize();
     Parser parser = createParser(listener);
+    parser.enableAssertInitializer = enableAssertInitializer;
     parser.parseAsync = parseAsync;
     parser.parseFunctionBodies = parseFunctionBodies;
     parser.parseGenericMethods = enableGenericMethods;
     parser.parseGenericMethodComments = enableGenericMethodComments;
     CompilationUnit unit = parser.parseCompilationUnit(token);
     expect(unit, isNotNull);
     listener.assertErrorsWithCodes(errorCodes);
     return unit;
   }
 
@@ skipping 4101 matching lines @@
   }
 
   void test_parseConstructor() {
     // TODO(brianwilkerson) Implement tests for this method.
 //    parse("parseConstructor", new Class[] {Parser.CommentAndMetadata.class,
 //        Token.class, Token.class, SimpleIdentifier.class, Token.class,
 //        SimpleIdentifier.class, FormalParameterList.class}, new Object[] {emptyCommentAndMetadata(),
 //        null, null, null, null, null, null}, "");
   }
 
+  void test_parseConstructor_assert() {
+    enableAssertInitializer = true;
+    ClassMember classMember = parse("parseClassMember", <Object>["C"],
+        "C(x, y) : _x = x, assert (x < y), _y = y;");
+    expect(classMember, new isInstanceOf<ConstructorDeclaration>());
+    ConstructorDeclaration constructor = classMember as ConstructorDeclaration;
+    NodeList<ConstructorInitializer> initializers = constructor.initializers;
+    expect(initializers, hasLength(2));
+  }
+
   void test_parseConstructor_with_pseudo_function_literal() {
     // "(b) {}" should not be misinterpreted as a function literal even though
     // it looks like one.
     ClassMember classMember =
         parse("parseClassMember", <Object>["C"], "C() : a = (b) {}");
     EngineTestCase.assertInstanceOf((obj) => obj is ConstructorDeclaration,
         ConstructorDeclaration, classMember);
     ConstructorDeclaration constructor = classMember as ConstructorDeclaration;
     NodeList<ConstructorInitializer> initializers = constructor.initializers;
     expect(initializers, hasLength(1));
@@ skipping 4223 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;
   }
 }