#!/usr/bin/perl use strict; use warnings; use Test::More; use Test::Fatal; BEGIN { use_ok('Moose::Util::TypeConstraints'); } { package Some::Class; use Moose::Util::TypeConstraints; subtype 'MySubType' => as 'Int' => where { 1 }; } like( exception { package Some::Other::Class; use Moose::Util::TypeConstraints; subtype 'MySubType' => as 'Int' => where { 1 }; }, qr/cannot be created again/, 'Trying to create same type twice throws' ); done_testing;