test/schemas/extension2_1.xsd

<?xml version="1.0" encoding="UTF-8"?>
   <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
              xmlns="http://myns"
              targetNamespace="http://myns"
              elementFormDefault="qualified"
              attributeFormDefault="unqualified"
              xml:lang="en">

     <xs:complexType name="dataInlineType">
       <xs:complexContent>
         <xs:extension base="xs:anyType"/>
       </xs:complexContent>
     </xs:complexType>
     
     <xs:element name="foo" type="dataInlineType"/>

   </xs:schema>