title: groovy.lang.MissingPropertyException: No such property: owner for class: Mother
body: <p>I'm working on the following code:</p>
  
  <p>caught exception at 'this.owner' which in the Closure of birth method.</p>
  
  <pre><code>class Mother {
              int field = 1
              int foo(){
                  return 2
              }
              Closure birth(param){
                  def local = 3
                  def closure = {caller -&gt; [this,field,foo(),local,param,caller,this.owner]} 
                  return closure
              }
          }
  
          Mother m = new Mother();
          closure = m.birth(4);
  
          context = closure.call(this);
          println context[0].class.name
  
          assert context[1..4] == [1,2,3,4]
          assert context[5] instanceof Script
          assert context[6] instanceof Mother
  
          fClosure = m.birth(4);
          sClosure = m.birth(4);
          assert false == fClosure.is(sClosure)
  </code></pre>
  
  <p>Which, when run finishes with:</p>
  
  <blockquote>
    <p>'this.owner' caught groovy.lang.MissingPropertyException: No such
    property: owner for class: Mother</p>
  </blockquote>
  
  <p>Why is that?</p>