Rework the parser to improve performance

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 6103 matching lines @@
     ShowCombinator combinator = combinators[0] as ShowCombinator;
     expect(combinator, isNotNull);
     expect(combinator.keyword, isNotNull);
     expect(combinator.shownNames, hasLength(1));
   }
 
   void test_parseCommentAndMetadata_c() {
     CommentAndMetadata commentAndMetadata =
         parse4("parseCommentAndMetadata", "/** 1 */ void");
     expect(commentAndMetadata.comment, isNotNull);
-    expect(commentAndMetadata.metadata, hasLength(0));
+    expect(commentAndMetadata.metadata, isNull);
   }
 
   void test_parseCommentAndMetadata_cmc() {
     CommentAndMetadata commentAndMetadata =
         parse4("parseCommentAndMetadata", "/** 1 */ @A /** 2 */ void");
     expect(commentAndMetadata.comment, isNotNull);
     expect(commentAndMetadata.metadata, hasLength(1));
   }
 
   void test_parseCommentAndMetadata_cmcm() {
@@ skipping 35 matching lines @@
     CommentAndMetadata commentAndMetadata =
         parse4("parseCommentAndMetadata", "@A @B(x) void");
     expect(commentAndMetadata.comment, isNull);
     expect(commentAndMetadata.metadata, hasLength(2));
   }
 
   void test_parseCommentAndMetadata_none() {
     CommentAndMetadata commentAndMetadata =
         parse4("parseCommentAndMetadata", "void");
     expect(commentAndMetadata.comment, isNull);
-    expect(commentAndMetadata.metadata, hasLength(0));
+    expect(commentAndMetadata.metadata, isNull);
   }
 
   void test_parseCommentAndMetadata_singleLine() {
     CommentAndMetadata commentAndMetadata = parse4(
         "parseCommentAndMetadata",
         r'''
 /// 1
 /// 2
 void''');
     expect(commentAndMetadata.comment, isNotNull);
-    expect(commentAndMetadata.metadata, hasLength(0));
+    expect(commentAndMetadata.metadata, isNull);
   }
 
   void test_parseCommentReference_new_prefixed() {
     CommentReference reference =
         parse("parseCommentReference", <Object>["new a.b", 7], "");
     PrefixedIdentifier prefixedIdentifier = EngineTestCase.assertInstanceOf(
         (obj) => obj is PrefixedIdentifier,
         PrefixedIdentifier,
         reference.identifier);
     SimpleIdentifier prefix = prefixedIdentifier.prefix;
@@ skipping 790 matching lines @@
     EngineTestCase.assertInstanceOf(
         (obj) => obj is ParenthesizedExpression,
         ParenthesizedExpression,
         (initializer as ConstructorFieldInitializer).expression);
     EngineTestCase.assertInstanceOf(
         (obj) => obj is BlockFunctionBody, BlockFunctionBody, constructor.body);
   }
 
   void test_parseConstructorFieldInitializer_qualified() {
     ConstructorFieldInitializer invocation =
-        parse4("parseConstructorFieldInitializer", "this.a = b");
+        parse2("parseConstructorFieldInitializer", [true], "this.a = b");
     expect(invocation.equals, isNotNull);
     expect(invocation.expression, isNotNull);
     expect(invocation.fieldName, isNotNull);
     expect(invocation.thisKeyword, isNotNull);
     expect(invocation.period, isNotNull);
   }
 
   void test_parseConstructorFieldInitializer_unqualified() {
     ConstructorFieldInitializer invocation =
-        parse4("parseConstructorFieldInitializer", "a = b");
+        parse2("parseConstructorFieldInitializer", [false], "a = b");
     expect(invocation.equals, isNotNull);
     expect(invocation.expression, isNotNull);
     expect(invocation.fieldName, isNotNull);
     expect(invocation.thisKeyword, isNull);
     expect(invocation.period, isNull);
   }
 
   void test_parseConstructorName_named_noPrefix() {
     ConstructorName name = parse4("parseConstructorName", "A.n;");
     expect(name.type, isNotNull);
@@ skipping 2661 matching lines @@
     expect(literal.literal, isNotNull);
     expect(literal.value, isTrue);
   }
 
   void test_Parser() {
     expect(new Parser(null, null), isNotNull);
   }
 
   void test_parseRedirectingConstructorInvocation_named() {
     RedirectingConstructorInvocation invocation =
-        parse4("parseRedirectingConstructorInvocation", "this.a()");
+        parse2("parseRedirectingConstructorInvocation", [true], "this.a()");
     expect(invocation.argumentList, isNotNull);
     expect(invocation.constructorName, isNotNull);
     expect(invocation.thisKeyword, isNotNull);
     expect(invocation.period, isNotNull);
   }
 
   void test_parseRedirectingConstructorInvocation_unnamed() {
     RedirectingConstructorInvocation invocation =
-        parse4("parseRedirectingConstructorInvocation", "this()");
+        parse2("parseRedirectingConstructorInvocation", [false], "this()");
     expect(invocation.argumentList, isNotNull);
     expect(invocation.constructorName, isNull);
     expect(invocation.thisKeyword, isNotNull);
     expect(invocation.period, isNull);
   }
 
   void test_parseRelationalExpression_as() {
     AsExpression expression = parse4("parseRelationalExpression", "x as Y");
     expect(expression.expression, isNotNull);
     expect(expression.asOperator, isNotNull);
@@ skipping 1459 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;
   }
 }