XmlFile:test.xml
  PsiElement(XML_DOCUMENT)
    PsiElement(XML_PROLOG)
      PsiElement(XML_PROCESSING_INSTRUCTION)
        XmlToken:XML_PI_START('<?')
        XmlToken:XML_NAME('This')
        PsiWhiteSpace(' ')
        XmlToken:XML_TAG_CHARACTERS('is="PI"')
        XmlToken:XML_PI_END('?>')
    XmlTag:
      PsiErrorElement:Valid XML document must have a root tag
        <empty list>