XmlFile:test.xml
  PsiElement(XML_DOCUMENT)
    PsiElement(XML_PROLOG)
      PsiElement(XML_DOCTYPE)
        XmlToken:XML_DOCTYPE_START('<!DOCTYPE')
        PsiWhiteSpace(' ')
        XmlToken:XML_NAME('greeting')
        PsiWhiteSpace(' ')
        XmlToken:XML_DOCTYPE_SYSTEM('SYSTEM')
        PsiWhiteSpace(' ')
        XmlToken:XML_ATTRIBUTE_VALUE_TOKEN('"hello.dtd"')
        XmlToken:XML_DOCTYPE_END('>')
    XmlTag:
      PsiErrorElement:Valid XML document must have a root tag
        <empty list>