> It is not clear to me from the specification what the
> context/marks/substitutions of the resulting identifier will be in
> the following:
>
>    (datum->syntax (car (generate-temporaries '(_)) 'a)

You're right, but we may or may not want to nail this down fully.  The
only important criteria is that a binding for a generated temporary not be
able to capture anything other than references to the generated temporary
in the output of the same transformer.  This can be accomplished in more
than one way, e.g., by generating a fresh name or by generating a fresh
mark.

Kent