I saw this in constant.pm 
    $VERSION = '1.05';

    foreach my $name ( keys %constants ) {
        unless (defined $name) {
            require Carp;
            Carp::croak("Can't use undef as constant name");
        }
        ...
    }

[download]
and suddenly had an uncomfortable feeling. Are we supposed to watch out for nasty undefs slipping in there and taking up key seats in our hashes?

In reply to undef as a key in a hash. by fenLisesi

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