<t:root xmlns:t="test"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="test test.xsd">

  <!-- valid base but not restriction: a element -->
  <restriction-a z="z">
    <b>b</b>
    <c>c</c>
  </restriction-a>

</t:root>
