or download this
Q:\>perl -MMoose -e "package Moo;use Moose; has 'foo' => (is => 'ro',
+isa => 'Int'); no Moose; package main; my $bar = Moo->new({foo => 'bo
+om'});"
Attribute (foo) does not pass the type constraint because: Validation
+failed for 'Int' failed with value boom at g:/Systeme/tools/pe
...
Moose::Meta::Class::new_object('Moose::Meta::Class=HASH(0x1871
+04c)', 'HASH(0x3ea354)') called at g:/Systeme/tools/perl-5.10.
0/perl/site/lib/Moose/Object.pm line 25
Moose::Object::new('Moo', 'HASH(0x12ca3ec)') called at -e line
+ 1