The shelf 'X' is assigned a value that is never used.
or The shelf 'X' is referenced but never initialized.
or The shelf 'X' is never initialized or used.
OmniMark does some checking to make sure that all shelves are
both initialized and referenced. Since it is possible to initialize
shelves on the command-line, and counters and switches are
automatically initialized to acceptable values, this is not
necessarily an error. It
is also conceivable that a shelf would be assigned a value that is
deliberately never needed again.