in reply to Re: Risks in the oblivious use of qr//
in thread Risks in the oblivious use of qr//

Which is indeed what's going on.
$ perl -wle'$_=qr/foo/; print ref; print $$_' Regexp Use of uninitialized value in print at -e line 1.
qr// returns a blessed reference which, well, doesn't point at anything. At least not anything you can see from the Perl end of things.

Makeshifts last the longest.