##
> perl -we "print 0+'abc'"
Argument "abc" isn't numeric in addition (+) at -e line 1.
0
> perl -wde 0
DB<1> print 0+'abc'
0
####
eval "use strict;";
eval "use warnings;";
eval "print undef;";
eval 'print $x[undef];';
####
use strict;
use warnings;
1
####
perl -de 0
DB<1> use e; print $x[undef]