anchor.diff:    writeLine(int column, String text) {
       // Write any pending newlines.
       while (newlinesNeeded > 0) {
  -      buffer.add('\n');
  +      buffer.write('\n');
         newlinesNeeded--;
       }
   
  
positive.code: 
    buildAllowedList(Option option) {
      var allowedBuffer = new StringBuffer();
      allowedBuffer.add('[');
      bool first = true;
      for (var allowed in option.allowed) {
        if (!first) allowedBuffer.add(', ');
        allowedBuffer.add(allowed);
        if (allowed == option.defaultValue) {
          allowedBuffer.add(' (default)');
        }
        first = false;
      }
      allowedBuffer.add(']');
      return allowedBuffer.toString();
    }
  }
  
negative.code: /** Pads [source] to [length] by adding spaces at the end. */
  String padRight(String source, int length) {
    final result = new StringBuffer();
    result.write(source);
  
    while (result.length < length) {
      result.write(' ');
    }
  
    return result.toString();
  }
  