private void CheckNode(TagNode tn, DiagnosticEmitter e)
        {
            if (((IWikitextParsingInfo)tn).InferredClosingMark)
            {
                e.OpenTagNotClosed(tn.ToRange(), tn.Name);
            }
            var names = new HashSet <string>();

            foreach (var attr in tn.Attributes)
            {
                if (attr.Name == null)
                {
                    continue;
                }
                var name = attr.Name.ToString().Trim();
                if (!names.Add(name))
                {
                    e.DuplicateTagAttribute(attr.ToRange(), name, tn.Name);
                }
            }
        }