title: Override default attribute when using Moose roles
body: <p>I can't override a already declared attribute in a role with <code>MooseX::Declare</code>.</p>
  
  <pre><code>use MooseX::Declare;
  
  role Person {
  has 'name' =&gt; (
      is =&gt; 'ro',
      isa =&gt; 'Str',
      default =&gt; 'John',
      );
  }
  
  class Me with Person {
  has '+name' =&gt; (
          default =&gt; 'Michael',
      );
  }
  </code></pre>
  
  <p>The error which is reported by executing the code:</p>
  
  <pre><code>Could not find an attribute by the name of 'name' to inherit from in Me at /usr/lib/perl5/Moose/Meta/Class.pm line 711
  Moose::Meta::Class::_process_inherited_attribute('Moose::Meta::Class=HASH(0x2b20628)', 'name', 'default', 'Michael', 'definition_context', 'HASH(0x114fd38)') called at /usr/lib/perl5/Moose/Meta/Class.pm line 694
  Moose::Meta::Class::_process_attribute('Moose::Meta::Class=HASH(0x2b20628)', '+name', 'default', 'Michael', 'definition_context', 'HASH(0x114fd38)') called at /usr/lib/perl5/Moose/Meta/Class.pm line 566
  Moose::Meta::Class::add_attribute('Moose::Meta::Class=HASH(0x2b20628)', '+name', 'default', 'Michael', 'definition_context', 'HASH(0x114fd38)') called at /usr/lib/perl5/Moose.pm line 79
  Moose::has('Moose::Meta::Class=HASH(0x2b20628)', '+name', 'default', 'Michael') called at /usr/lib/perl5/Moose/Exporter.pm line 370
  Moose::has('+name', 'default', 'Michael') called at Test.pm line 12
  main::__ANON__() called at /usr/share/perl5/MooseX/Declare/Syntax/MooseSetup.pm line 81
  MooseX::Declare::Syntax::MooseSetup::__ANON__('CODE(0x2b0be20)') called at Test.pm line 21
  </code></pre>
  
  <p>This works, but its not based on roles:</p>
  
  <pre><code>class Person {
  has 'name' =&gt; (
      is =&gt; 'ro',
      isa =&gt; 'Str',
      default =&gt; 'John',
      );
  }
  
  class Me extends Person {
  has '+name' =&gt; (
      default =&gt; 'Michael',
      );
  }
  </code></pre>
  
  <p>What is wrong with my code when using roles? Is there no possibility to override a attribute behaviour?</p>