Please describe the problem:
xmllint refuses as invalid some XML files described by a RelaxNG schema when
this schema includes interleave. 



Steps to reproduce:
Here is a simplified version of the original problem, which still
demonstrates the bug.

The schema:

<?xml version="1.0" encoding="UTF-8"?>
<grammar xmlns="http://relaxng.org/ns/structure/1.0">
  <start>
    <ref name="content"/>
  </start>
  <define name="content">
    <element name="content">
      <mixed>
        <oneOrMore>
          <element name="para">
            <interleave>
              <zeroOrMore>
                <ref name="inlines"/>
              </zeroOrMore>
              <zeroOrMore>
                <ref name="code"/>
              </zeroOrMore>
            </interleave>
          </element>
        </oneOrMore>
      </mixed>
    </element>
  </define>
  <define name="inlines">
    <interleave>
      <zeroOrMore>
        <ref name="link"/>
      </zeroOrMore>
      <zeroOrMore>
        <ref name="emphasis"/>
      </zeroOrMore>
      <zeroOrMore>
        <text/>
      </zeroOrMore>
    </interleave>
  </define>
  <define name="code">
    <element name="code">
      <text/>
    </element>
  </define>
  <define name="emphasis">
    <element name="emphasis">
      <text/>
    </element>
  </define>
  <define name="link">
    <element name="link">
      <text/>
    </element>
  </define>
</grammar>

The test file:

<content>
<para>text
<code>foo</code>
text again
<code>bar</code>
</para>
</content>

Another test file which is accepted (because it only has one <code>
element):

<content>
<para>text
<code>foo</code>
text <emphasis>again</emphasis>
</para>
<para>Another para</para>
</content>

The command-line to show the bug:

xmllint --noout --relaxng schema.rng test.xml


Actual results:
test.xml:2: element para: Relax-NG validity error : Expecting an element got text
Relax-NG validity error : Extra element text in interleave
test.xml:2: element para: Relax-NG validity error : Element para failed to
validate content
test.xml fails to validate


Expected results:
A message "text.xml validates"


Does this happen every time?
Yes

Other information:

The jing validator or the nxml-mode editor have no problem so I believe this is
a bug in libxml2.