dereference could take place if the inner reference had been returned by
a code block previously.
+=item *
+
+A tied variable returned from C<(??{...})> sees the inner values of match
+variables (i.e., the $1 etc. from any matches inside the block) in its
+FETCH method. This was not the case if a reference to an overloaded object
+was the last thing assigned to the tied variable. Instead, the match
+variables referred to the outer pattern during the FETCH call.
+
=back
=head1 Known Problems