error XPST0003:Unexpected token "{" when using p:xquery step with XQuery inline code with embedded expression

[martin-honnen]

When I run the code

<?xml version="1.0" encoding="UTF-8"?>
<p:declare-step name="test1"
    xmlns:p="http://www.w3.org/ns/xproc"
    xmlns:c="http://www.w3.org/ns/xproc-step" version="1.0"
    xpath-version="2.0">
    <p:input port="source"/>
    <p:output port="result"/>
    <p:xquery>
        <p:input port="query">
            <p:inline>
                <c:query><result>{document-uri(.)}</result></c:query>
            </p:inline>
        </p:input>
        <p:input port="parameters">
            <p:empty/>
        </p:input>
    </p:xquery>
</p:declare-step>

with Calabash 1.1.30-99 against any input source it gives the following error:

ERROR: file:/C:/SomePath/test-document-uri3.xpl:1:0:XPST0003:Unexpected token "{" at start of expression
ERROR: Unexpected token "{" at start of expression
ERROR: cause: file:/C:/SomePath/test-document-uri3.xpl:1:0:XPST0003:Unexpected token "{" at start of expression
ERROR: Pipeline failed: Unexpected token "{" at start of expression
ERROR: Underlying exception: Unexpected token "{" at start of expression

MorganaXProc 1.0.15 runs that code fine.