gistfile1.pl

package X;
use Moose;

has foo => (
    is => 'rw',
);

package A;
use Moose;

extends 'X';

has foo => (
    default => 'foo',
);

package main;
use strict;
use warnings;
use Test::More qw(no_plan);

is(A->new->foo, 'foo');
is(A->new->foo('bar'), 'bar');