In the XQuery constructs
for $x as SequenceType ...
some $x as SequenceType ...
every $x as SequenceType ...
Saxon reports an error if the SequenceType contains an
occurrence indicator (+, *, ?). In fact the
specification allows an occurrence indicator here
although it has no meaning because the value of the
variable will always be a single item. The occurrence
indicator should thus be ignored rather than being