function-declaration-020.xqx 

The first (0-argument) function in this test

declare function foo:price () as xs:integer+
{
  100
};

is encoded as

      <xqx:functionDecl>
        <xqx:functionName xqx:prefix="foo">price</xqx:functionName>
        <xqx:paramList/>
        <xqx:functionBody>
          <xqx:pathExpr>
            <xqx:stepExpr>
              <xqx:filterExpr>
                <xqx:integerConstantExpr>
                  <xqx:value>100</xqx:value>
                </xqx:integerConstantExpr>
              </xqx:filterExpr>
            </xqx:stepExpr>
          </xqx:pathExpr>
        </xqx:functionBody>
      </xqx:functionDecl>

the specified return type of integer+ has been dropped.