[xslt] BUG: [1] != [position()=1]

[Matthias Benkmann <m s b gmx net>]

The attached 2 files demonstrate a bug in xsltproc/libxslt/libxml2

xml> xsltproc --version
Using libxml 20422, libxslt 10018 and libexslt 709
xsltproc was compiled against libxml 20422, libxslt 10018 and libexslt 709
libxslt 10018 was compiled against libxml 20422
libexslt 709 was compiled against libxml 20422

/xml> xsltproc bug.xsl test.xml
<?xml version="1.0"?>
21


The expected result (and the result produced by saxon) is 22, i.e. [1] is
supposed to be the same as [position()=1].

MSB
<?xml version="1.0" encoding="iso-8859-1"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform";>

<xsl:variable name="set1" 
                select="(/descendant::node()/attribute::*|/descendant::node())/ancestor-or-self::node()[1]"/>

<xsl:variable name="set2" 
                select="(/descendant::node()/attribute::*|/descendant::node())/ancestor-or-self::node()[position()=1]"/>

<xsl:template match="/">
  <xsl:value-of select="count($set1)"/>
  <xsl:value-of select="count($set2)"/>
</xsl:template>
                
</xsl:stylesheet>
<?xml version="1.0" encoding="iso-8859-1"?>

<net foo="bar"/>