ken@ganymede: ~/tmp
$ perl -Mstrict -Mwarnings -MO=Deparse,-p -E '
> my $reward;
> my $message = "Congrats" unless not defined $reward;
> '
use warnings;
use strict 'refs';
BEGIN {
    $^H{'feature_unicode'} = q(1);
    $^H{'feature_say'} = q(1);
    $^H{'feature_state'} = q(1);
    $^H{'feature_switch'} = q(1);
}
my($reward);
(defined($reward) and (my $message = 'Congrats'));
-e syntax OK
ken@ganymede: ~/tmp
$