anchor.diff:          children.add(_stackToTextSpan(list[i]));
         }
   
  -      String text = null;
  +      String text;
         if (children.length == 1 && _isPlainText(children[0])) {
           text = children[0].text;
           children = null;
  
positive.code:       _Block newBlock = new _Block(element.tag, element.attributes, _markdownStyle, new List<String>.from(_listIndents), blockList.length);
        blockList.add(newBlock);
      } else {
        _LinkInfo linkInfo = null;
        if (element.tag == 'a') {
          linkInfo = _linkHandler.createLinkInfo(element.attributes['href']);
        }
  
negative.code:   }
  }
  
  abstract class SyntaxHighlighter { // ignore: one_member_abstracts
    TextSpan format(String source);
  }
  
  class _DefaultSyntaxHighlighter extends SyntaxHighlighter{
    _DefaultSyntaxHighlighter(this.style);
  
    final TextStyle style;
  
    TextSpan format(String source) {
  