calabash: redefining standard step

consider the following pipeline

<p:pipeline name="pipeline"
            xmlns:p="http://www.w3.org/ns/xproc">

<!-- should not evaluate this declare-step //-->
<p:declare-step name="test1" type="p:identity">
    <p:input port="source" sequence="true"/>
    <p:output port="result" sequence="true"/>
    <p:count/>
</p:declare-step>

<p:identity/>

</p:pipeline>

should this not throw an error ? perhaps err:XS0002 or

cheers, Jim Fuller