Use FastaMessage instead of String. Part 1.

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

 // Copyright (c) 2017, 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 licenset hat can be found in the LICENSE file.
 
 library dart_scanner.error_token;
 
 import '../../scanner/token.dart' show BeginToken, TokenType, TokenWithComment;
 
 import '../fasta_codes.dart'
     show
-        FastaCode,
+        Code,
         codeAsciiControlCharacter,
         codeEncoding,
         codeExpectedHexDigit,
         codeMissingExponent,
         codeNonAsciiIdentifier,
         codeNonAsciiWhitespace,
         codeUnexpectedDollarInString,
         codeUnmatchedToken,
         codeUnterminatedComment,
         codeUnterminatedString,
@@ skipping 48 matching lines @@
 
   /// This is a token that wraps around an error message. Return 1
   /// instead of the size of the length of the error message.
   @override
   int get length => 1;
 
   String get lexeme => throw assertionMessage;
 
   String get assertionMessage;
 
-  FastaCode get errorCode;
+  Code get errorCode;
 
   int get character => null;
 
   String get start => null;
 
   int get endOffset => null;
 
   BeginToken get begin => null;
 
   @override
   Token copy() {
     throw 'unsupported operation';
   }
 }
 
 /// Represents an encoding error.
 class EncodingErrorToken extends ErrorToken {
   EncodingErrorToken(int charOffset) : super(charOffset);
 
   String toString() => "EncodingErrorToken()";
 
   String get assertionMessage => "Unable to decode bytes as UTF-8.";
 
-  FastaCode get errorCode => codeEncoding;
+  Code get errorCode => codeEncoding;
 }
 
 /// Represents a non-ASCII character outside a string or comment.
 class NonAsciiIdentifierToken extends ErrorToken {
   final int character;
 
   NonAsciiIdentifierToken(this.character, int charOffset) : super(charOffset);
 
   String toString() => "NonAsciiIdentifierToken($character)";
 
   String get assertionMessage {
     String c = new String.fromCharCodes([character]);
     String hex = character.toRadixString(16);
     String padding = "0000".substring(hex.length);
     hex = "$padding$hex";
     return "The non-ASCII character '$c' (U+$hex) can't be used in identifiers,"
         " only in strings and comments.\n"
         "Try using an US-ASCII letter, a digit, '_' (an underscore),"
         " or '\$' (a dollar sign).";
   }
 
-  FastaCode get errorCode => codeNonAsciiIdentifier;
+  Code get errorCode => codeNonAsciiIdentifier;
 }
 
 /// Represents a non-ASCII whitespace outside a string or comment.
 class NonAsciiWhitespaceToken extends ErrorToken {
   final int character;
 
   NonAsciiWhitespaceToken(this.character, int charOffset) : super(charOffset);
 
   String toString() => "NonAsciiWhitespaceToken($character)";
 
   String get assertionMessage {
     String hex = character.toRadixString(16);
     return "The non-ASCII space character U+$hex can only be used in strings "
         "and comments.";
   }
 
-  FastaCode get errorCode => codeNonAsciiWhitespace;
+  Code get errorCode => codeNonAsciiWhitespace;
 }
 
 /// Represents an ASCII control character outside a string or comment.
 class AsciiControlCharacterToken extends ErrorToken {
   final int character;
 
   AsciiControlCharacterToken(this.character, int charOffset)
       : super(charOffset);
 
   String toString() => "AsciiControlCharacterToken($character)";
 
   String get assertionMessage {
     String hex = character.toRadixString(16);
     return "The control character U+$hex can only be used in strings and "
         "comments.";
   }
 
-  FastaCode get errorCode => codeAsciiControlCharacter;
+  Code get errorCode => codeAsciiControlCharacter;
 }
 
 /// Represents an unterminated string.
 class UnterminatedToken extends ErrorToken {
   final String start;
   final int endOffset;
 
   UnterminatedToken(this.start, int charOffset, this.endOffset)
       : super(charOffset);
 
   String toString() => "UnterminatedToken($start)";
 
   String get assertionMessage => "'$start' isn't terminated.";
 
   int get charCount => endOffset - charOffset;
 
-  FastaCode get errorCode {
+  Code get errorCode {
     switch (start) {
       case '1e':
         return codeMissingExponent;
 
       case '"':
       case "'":
       case '"""':
       case "'''":
       case 'r"':
       case "r'":
@@ skipping 24 matching lines @@
   final BeginToken begin;
 
   UnmatchedToken(BeginToken begin)
       : this.begin = begin,
         super(begin.charOffset);
 
   String toString() => "UnmatchedToken(${begin.lexeme})";
 
   String get assertionMessage => "'$begin' isn't closed.";
 
-  FastaCode get errorCode => codeUnmatchedToken;
+  Code get errorCode => codeUnmatchedToken;
 }