#!/usr/bin/perl -w
use strict;
my $foo = Foo->new;
"$foo";

package Foo;
use strict;
use overload '""' => 'stringy';
sub new {bless {}, __PACKAGE__}
sub stringy { print "OK!\n"}

##</code><code>##

Useless use of string in void context at test.pl line 4.
OK!