@Override
      public void visitXmlToken(final @NotNull XmlToken token) {
        if (isXmlFile(token) && token.getTokenType() == XmlTokenType.XML_NAME) {
          PsiElement element = token.getPrevSibling();
          while(element instanceof PsiWhiteSpace) element = element.getPrevSibling();

          if (element instanceof XmlToken && ((XmlToken)element).getTokenType() == XmlTokenType.XML_START_TAG_START) {
            PsiElement parent = element.getParent();

            if (parent instanceof XmlTag tag && !(token.getNextSibling() instanceof OuterLanguageElement)) {
              checkUnboundNamespacePrefix(tag, tag, tag.getNamespacePrefix(), token, holder, isOnTheFly);
            }
          }
        }
      }
@Override
      public void visitXmlToken(final @NotNull XmlToken token)