Strange warning in Math.xsl using Saxon9

Hello,

 

I have recently updated my Docbook processing system to include Saxon 
9.4.0.7. Everything works well but I have a warning that does not make sense and 
maybe someone here can explain it.

 

    Warning: at xsl:variable on line 65 column 38 of 
math.xsl:
      SXWN9001: A variable with no 
following sibling instructions has no effect

 

Since I am processing for FO, it is referencing fo/math.xsl and this 
template:

 

<xsl:template match="equation/alt[@role='tex'] | 
informalequation/alt[@role='tex'] 
|
                     
equation/mediaobject/textobject[@role='tex'] 
|
                     
informalequation/mediaobject/textobject[@role='tex']" priority="1">
  
<xsl:variable name="output.delims"> <!-- Line 65 
-->
    <xsl:call-template 
name="tex.math.output.delims"/>
  
</xsl:variable>
</xsl:template>

 

As I understand it, this template only come into action when 
the "role='tex' " is added to an equation or its children. However, I do 
not reference that in any of my XML Docbook files or my own XSL layer. I have 
grepped for it in the XML and XSL but to no avail.

 

Is this a normal warning when using Saxon 9.4 or is it something that I am 
doing? Has anyone else seen it? It doesn't show up when I use XSLTPROC and Saxon 
6.5.5 on the same stylesheets. Or is this an issue with 1.78.1?

 

Regards,

Dean Nelson