libxml2/test/schemas/bug455953_0.xsd

<?xml version="1.0" encoding="UTF-8" ?> 
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
           targetNamespace="http://www.tempuri.org/MainSchema"
           xmlns:tns="http://www.tempuri.org/MainSchema"
           xmlns:ns="http://www.tempuri.org/ImportedSchema"
           elementFormDefault="qualified" >
           
  <xs:import namespace="http://www.tempuri.org/ImportedSchema" schemaLocation="./import-455953.xsd" />
  
  <xs:complexType name="MyMainType">
    <xs:sequence>
      <xs:element name="MainA">
        <xs:complexType>
          <xs:attribute name="MainID" type="xs:int"/>
        </xs:complexType>
      </xs:element>
      <xs:element ref="ns:AnotherElement" />
    </xs:sequence>
  </xs:complexType>

  <xs:element name="MainElement" type="tns:MyMainType">
    <xs:key name="MainKey" >
      <xs:selector xpath="tns:MainA" />
      <xs:field xpath="@MainID" />
    </xs:key>
  </xs:element>


</xs:schema>