[xsl] error in xsl:key

["Vladimir Nesterovsky" <vladimir@xxxxxxxxxxxxxxxxxxxx>]

Hello!

I have an xsl:key like this:

<xsl:key
 name="t:type-name"
 match="type"
 use="t:get-type-name(.)"/

Please don't bother with what function's really doing, except that
for a certain circumstances it may issue an error.

My question is what this should result into, when error occurs?

E.g. in Saxon 9.1 this results in error when I try to access a key() 
function,
with valid $key-value.
--
Vladimir Nesterovsky
http://www.nesterovsky-bros.com/