more fixes for fasta analyzer integration

pkg/front_end/lib/src/fasta/scanner/token.dart

 // Copyright (c) 2011, 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 fasta.scanner.token;
 
 import '../../scanner/token.dart' as analyzer;
 import '../../scanner/token.dart' show Token, TokenType;
 
 import 'token_constants.dart' show IDENTIFIER_TOKEN;
@@ skipping 100 matching lines @@
     if (!canonicalize) return s;
     return canonicalizer.canonicalize(s, start, end, false);
   }
 
   static String decodeUtf8(List<int> data, int start, int end, bool asciiOnly) {
     return canonicalizer.canonicalize(data, start, end, asciiOnly);
   }
 
   @override
   Token copy() => new StringToken._(
-      type, valueOrLazySubstring, charOffset, precedingComments);
+      type, valueOrLazySubstring, charOffset, copyComments(precedingComments));
 
   @override
   String value() => lexeme;
 }
 
 /**
  * A String-valued token that does not exist in the original source.
  */
 class SyntheticStringToken extends StringToken
     implements analyzer.SyntheticStringToken {
   SyntheticStringToken(TokenType type, String value, int offset,
       [analyzer.CommentToken precedingComments])
       : super._(type, value, offset, precedingComments);
 
   @override
   int get length => 0;
 
   @override
   Token copy() => new SyntheticStringToken(
-      type, valueOrLazySubstring, offset, precedingComments);
+      type, valueOrLazySubstring, offset, copyComments(precedingComments));
 }
 
 class CommentToken extends StringToken implements analyzer.CommentToken {
   @override
   analyzer.TokenWithComment parent;
 
   /**
    * Creates a lazy comment token. If [canonicalize] is true, the string
    * is canonicalized before the token is created.
    */
@@ skipping 160 matching lines @@
       identical(value, "<=") ||
       identical(value, "<") ||
       identical(value, "&") ||
       identical(value, "^") ||
       identical(value, "|");
 }
 
 bool isTernaryOperator(String value) => identical(value, "[]=");
 
 bool isMinusOperator(String value) => identical(value, "-");