package Null::Object;

use overload 'bool' => \&bool;
my $self;

sub new { 
    $self ||= bless {}, shift
}

sub AUTOLOAD { $self }

sub bool {
    return;
}

package main;

my $null = Null::Object->new;
$null->foo->bar->baz;

if ($null) {
    print "We shouldn't be here!";
}
else {
    print "We are false!";
}