package Foo;

use warnings;
use strict;

my %data = qw/foo bar/;

our $AUTOLOAD;
sub AUTOLOAD {
    my ($self, @args) = @_;
    my ($pkg, $field) = (__PACKAGE__, $AUTOLOAD);
    $field =~ s/${pkg}:://;

    ## uncommenting any of these, makes the code work
    #%data;
    #() = %data;
    #map $_, %data;
    #map $_, \%data;
    #$::qwerty123 = %data;

    eval "*$field = sub { return \\%$field; };";
    $@ and die "eval failed: $@\n";

    goto &$field;
}

1;


##</code><code>##

$ perl -I. -MData::Dumper -MFoo -e'print Dumper (Foo->data)'
Variable "%data" is not available at (eval 1) line 1.
$VAR1 = {};

##</code><code>##

$ perl -I. -MData::Dumper -MFoo -e'print Dumper (Foo->data)'
Useless use of private hash in void context at Foo.pm line 16.
$VAR1 = {
          'foo' => 'bar'
        };

##</code><code>##

package main;
use warnings;
use strict;
use Data::Dumper;
print Dumper (Foo->data);