anchor.diff:      Token token = scanString(parserSource).tokens;
       while (!token.isEof) {
         if (token.isIdentifier) {
  -        String fastaErrorCode;
  +        String? fastaErrorCode;
           String lexeme = token.lexeme;
           if (lexeme.length > 7) {
             if (lexeme.startsWith('message')) {
  
positive.code:           untranslatedFastaErrorCodes.add(fastaErrorCode);
          }
        }
        token = token.next;
      }
      if (untranslatedFastaErrorCodes.isNotEmpty) {
        print('');
  
negative.code:       print('');
        print('The following ParserErrorCodes could be auto generated:');
        for (String analyzerName in analyzerToFasta.keys.toList()..sort()) {
          List<String> fastaNames = analyzerToFasta[analyzerName]!;
          if (fastaNames.length == 1) {
            print('  $analyzerName = ${fastaNames.first}');
          } else {
  