<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">

  <xsd:element name="A" type="X"/>

  <!-- The purpose of this element is:
       a) To have a fixed attribute use
       b) To have an attribute with a fixed attribute declaration
       c) To have a complex type with simple content and a fixed value
       d) To have an element declaration with a fixed value
   -->
  <xsd:element name="B" fixed="howdy">
    <xsd:complexType>
      <xsd:simpleContent>
        <xsd:extension base="xsd:string">
          <xsd:attribute ref="fixedAttr" use="required" fixed="hello"/>
        </xsd:extension>
      </xsd:simpleContent>
    </xsd:complexType>
  </xsd:element>
  
  <xsd:element name="D" type="xsd:string" fixed="hey"/>

  <xsd:attribute name="attr" type="xsd:string"/>

  <xsd:attribute name="unparsedEntityAttr" type="xsd:ENTITIES"/>

  <xsd:attribute name="fixedAttr" type="xsd:string" fixed="hello"/>

  <xsd:complexType name="X">
    <xsd:sequence>
      <xsd:any processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
    </xsd:sequence>
    <xsd:attribute ref="attr"/>
    <xsd:attribute ref="unparsedEntityAttr"/>
  </xsd:complexType>

  <xsd:complexType name="Y">
    <xsd:complexContent>
	    <xsd:restriction base="X">
		    <xsd:sequence>
		      <xsd:any processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
		    </xsd:sequence>
		    <xsd:attribute ref="attr" fixed="typeY"/>
		    <xsd:attribute ref="unparsedEntityAttr" use="prohibited"/>
	    </xsd:restriction>
    </xsd:complexContent>
  </xsd:complexType>

  <!-- Z is the same as X, but is not derived from X. -->
  <xsd:complexType name="Z">
    <xsd:sequence>
      <xsd:any processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
    </xsd:sequence>
    <xsd:attribute ref="attr"/>
    <xsd:attribute ref="unparsedEntityAttr"/>
  </xsd:complexType>
  
  <xsd:complexType name="idType">
    <xsd:complexContent>
	    <xsd:extension base="X">
		    <xsd:attribute name="idAttr" type="xsd:ID"/>
	    </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:complexType name="idrefType">
    <xsd:complexContent>
	    <xsd:extension base="X">
		    <xsd:attribute name="idrefAttr" type="xsd:IDREF"/>
	    </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

</xsd:schema>