title: ERROR! Unexpected Exception, this is probably a bug: argument of type 'bool' is not iterable
body: <p>I've got an error with Ansible, that I don't understand:</p>
  
  <p><code>ERROR! Unexpected Exception, this is probably a bug: argument of type 'bool' is not iterable</code></p>
  
  <p>It happens in in role where I call a var file:</p>
  
  <pre><code>- name: import pdt vars
    include_vars:
      file: "{{ pdt_type }}.yml"
  </code></pre>
  
  <p>The "{{ pdt_type }}.yml" contains:</p>
  
  <pre><code>pdt_pkg:
    - { name: "zzz-libs" }
    - { name: "zzz-core" }
  </code></pre>
  
  <p>What is wrong with that? Is it really a bug?</p>