support subclasses of classes that use MX::Traits

lib/MooseX/Traits.pm

@@ -15,7 +15,7 @@ has '_trait_namespace' => (
 
 my $transform_trait = sub {
     my ($class, $name) = @_;
-    my $namespace = $class->meta->get_attribute('_trait_namespace');
+    my $namespace = $class->meta->find_attribute_by_name('_trait_namespace');
     my $base;
     if($namespace->has_default){
         $base = $namespace->default;

t/subclass.t

@@ -0,0 +1,26 @@
+use strict;
+use warnings;
+use Test::More tests => 3;
+use Test::Exception;
+
+{ package Foo;
+  use Moose;
+  with 'MooseX::Traits';
+
+  package Bar;
+  use Moose;
+  extends 'Foo';
+
+  package Trait;
+  use Moose::Role;
+
+  sub foo { return 42 };
+}
+
+my $instance;
+lives_ok {
+    $instance = Bar->new_with_traits( traits => ['Trait'] );
+} 'creating instance works ok';
+
+ok $instance->does('Trait'), 'instance does trait';
+is $instance->foo, 42, 'trait works';