cleanup fasta token classes

pkg/analyzer/lib/src/generated/parser.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.
 
 import 'dart:collection';
 import "dart:math" as math;
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/standard_ast_factory.dart';
 import 'package:analyzer/dart/ast/token.dart';
@@ skipping 1820 matching lines @@
             if (Character.isLetterOrDigit(charAfterLeft)) {
               int nameEnd = StringUtilities.indexOfFirstNotLetterDigit(
                   comment, leftIndex + 1);
               String name = comment.substring(leftIndex + 1, nameEnd);
               nameToken =
                   new StringToken(TokenType.IDENTIFIER, name, nameOffset);
             } else {
               nameToken = new SyntheticStringToken(
                   TokenType.IDENTIFIER, '', nameOffset);
             }
-            nameToken.setNext(new SimpleToken(TokenType.EOF, nameToken.end));
+            nameToken.setNext(new Token.eof(nameToken.end));
             references.add(astFactory.commentReference(
                 null, astFactory.simpleIdentifier(nameToken)));
             token.references.add(nameToken);
             // next character
             rightIndex = leftIndex + 1;
           }
           leftIndex = comment.indexOf('[', rightIndex);
         } else {
           leftIndex = comment.indexOf('[', range[1]);
         }
@@ skipping 112 matching lines @@
         // is being generated).
         _reportErrorForToken(ParserErrorCode.UNEXPECTED_TOKEN, _currentToken,
             [_currentToken.lexeme]);
         _advance();
       } else {
         CompilationUnitMember member;
         try {
           member = parseCompilationUnitMember(commentAndMetadata);
         } on _TooDeepTreeError {
           _reportErrorForToken(ParserErrorCode.STACK_OVERFLOW, _currentToken);
-          Token eof = new Token(TokenType.EOF, 0);
-          eof.previous = eof;
-          eof.setNext(eof);
+          Token eof = new Token.eof(0);
           return astFactory.compilationUnit(eof, null, null, null, eof);
         }
         if (member != null) {
           declarations.add(member);
         }
       }
       if (identical(_currentToken, memberStart)) {
         _reportErrorForToken(ParserErrorCode.UNEXPECTED_TOKEN, _currentToken,
             [_currentToken.lexeme]);
         _advance();
@@ skipping 3824 matching lines @@
 
   /**
    * Clone all token starting from the given [token] up to the end of the token
    * stream, and return the first token in the new token stream.
    */
   Token _cloneTokens(Token token) {
     if (token == null) {
       return null;
     }
     token = token is CommentToken ? token.parent : token;
-    Token head = new Token(TokenType.EOF, -1);
-    head.setNext(head);
+    Token head = new Token.eof(-1);
     Token current = head;
     while (token.type != TokenType.EOF) {
       Token clone = token.copy();
       current.setNext(clone);
       current = clone;
       token = token.next;
     }
-    Token tail = new Token(TokenType.EOF, 0);
-    tail.setNext(tail);
+    Token tail = new Token.eof(0);
     current.setNext(tail);
     return head.next;
   }
 
   /**
    * Convert the given [method] declaration into the nearest valid top-level
    * function declaration (that is, the function declaration that most closely
    * captures the components of the given method declaration).
    */
   FunctionDeclaration _convertToFunctionDeclaration(MethodDeclaration method) =>
@@ skipping 2757 matching lines @@
     }
   }
 }
 
 /**
  * Instances of this class are thrown when the parser detects that AST has
  * too many nested expressions to be parsed safely and avoid possibility of
  * [StackOverflowError] in the parser or during later analysis.
  */
 class _TooDeepTreeError {}