docs: @Override
      public Ref memberRef(Context cx, Object elem, int memberTypeFlags) {
          boolean attribute = (memberTypeFlags & Node.ATTRIBUTE_FLAG) != 0;
          boolean descendants = (memberTypeFlags & Node.DESCENDANTS_FLAG) != 0;
          if (!attribute && !descendants) {
              // Code generation would use ecma(Get|Has|Delete|Set) for
              // normal name identifiers so one ATTRIBUTE_FLAG
              // or DESCENDANTS_FLAG has to be set
              throw Kit.codeBug();
          }
          XmlNode.QName qname = lib.toNodeQName(cx, elem, attribute);
          XMLName rv = XMLName.create(qname, attribute, descendants);
          rv.initXMLObject(this);
          return rv;
      }