Since this function is declared as returning a string, function argument conversion, static type analysis spots that  the declared return type (string) of the function does not match the actual type returned (NOTATION).  It therefore raises XPTY0004.

I think the intention of the test was to spot casting of the <tag>xs:integer</tag> to xs:NOTATION, and thus suggest removing "as xs:string".


     declare function local:clarkname($q as xs:NOTATION) as xs:string {
       $q
     };

     local:clarkname(<tag>xs:integer</tag>)