AB if-016

The pipeline

<p:declare-step xmlns:err="http://www.w3.org/ns/xproc-error" xmlns:p="http://www.w3.org/ns/xproc" name="pipeline" version="3.0">
   <p:output port="result"/>
   <p:identity name="producer">
      <p:with-input>
         <doc/>
      </p:with-input>
   </p:identity>
   <p:if test="true()">
      <p:with-input pipe="result1@producer"/>
      <p:identity>
         <p:with-input>
            <error/>
         </p:with-input>
      </p:identity>
   </p:if>
</p:declare-step>