gistfile1.txt

package Role1;
use Moose::Role;

has 'foo';

package Role2;
use Moose::Role;

with 'Role1';
has foo => (is => 'ro', isa => 'Int');

package Role3;
use Moose::Role;

with 'Role2';
has foo => (is => 'ro', isa => 'HashRef');

package FooBar;
use Moose;

with 'Role3';

package main;

FooBar->new(foo => {});