>perl -wMstrict -le
"print $_;
 my @ra = (0, 1, 2, 3);
 print grep { print qq{topicalized \$_: '$_'};  $ra[$_] } @ra;
 print $_;
"
Use of uninitialized value $_ in print at -e line 1.

topicalized $_: '0'
topicalized $_: '1'
topicalized $_: '2'
topicalized $_: '3'
123
Use of uninitialized value $_ in print at -e line 1.