<?xml version="1.0"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
            xmlns:xse="http://www.codesynthesis.com/xmlns/xml-schema-extension"
            xmlns:test="http://www.codesynthesis.com/xmlns/test"
            targetNamespace="http://www.codesynthesis.com/xmlns/test">

  <!-- unresolvable type -->
  
  <xsd:attribute name="attribute" type="xsd:IDREF" xse:refType="test:author"/>

</xsd:schema>
