title: Grails nested domains - addAll errors to top level domain object
body: <p>I have a Grails domain like this:</p>
  
  <pre><code>class User {
  ....
  Address address
  }
  </code></pre>
  
  <p>While saving the user, I want to validate the Address object as well and add all errors of Address object to the User object itself.</p>
  
  <p>I am trying to write a custom validator wherein I do <code>it.validate()</code>, but I am not able to find a way to "addAll" the error messages of address.</p>