<t:root xmlns:t="test"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="test test.xsd">
<!-- valid base but not restriction: sequence maxOccurs="1" --><restriction-az="z"><a>a</a><b>b</b><c>c</c><a>a</a><b>b</b><c>c</c></restriction-a></t:root>