XmlFile:test.xml
  PsiElement(XML_DOCUMENT)
    PsiElement(XML_PROLOG)
      <empty list>
    XmlTag:a
      XmlToken:XML_START_TAG_START('<')
      XmlToken:XML_NAME('a')
      XmlToken:XML_TAG_END('>')
      XmlText
        XmlToken:XML_DATA_CHARACTERS('xxx')
      PsiErrorElement:Unexpected end of file
        <empty list>