[xsl] SFINAE in xslt?

I'm curious if in the xslt 2.0 works SFINAE principle
(http://en.wikipedia.org/wiki/Substitution_failure_is_not_an_error)
regarding
template match?

For a template:

<xsl:template
match="if[then/exactly-one(signal)]"/>

and a code

<xsl:variable
name="statement" as="element()">
  <if>
    <then/>
  </if>
</xsl:variable>

<xsl:apply-templates select="$statement"/>

what are
chances to not to fail on the specified template?

Thanks.
--
Vladimir
Nesterovsky
http://www.nesterovsky-bros.com