title: angularjs ng-show with promise expression
body: <p>I'm using <code>ng-show</code> with an expression that resolves to a <em>promise</em> that resolves to a boolean.  When I do this I get the 10 digest iterations overflow.</p>
  
  <p>See <a href="http://plnkr.co/edit/XibYM0kCnXhKjNUeTsp3?p=preview" rel="noreferrer">http://plnkr.co/edit/XibYM0kCnXhKjNUeTsp3?p=preview</a></p>
  
  <pre><code>  &lt;body ng-controller="MainCtrl"&gt;
      &lt;p ng-show="returnsABoolean()"&gt;non promise&lt;/p&gt;
      &lt;p ng-show="returnsAPromiseThatResolvesToABoolean()"&gt;promise&lt;/p&gt;
    &lt;/body&gt;
  </code></pre>
  
  <p>Ctrl:</p>
  
  <pre><code>  $scope.returnsABoolean = ()-&gt;
      true
  
    $scope.returnsAPromiseThatResolvesToABoolean = ()-&gt;
      $q.when(false)
  </code></pre>
  
  <p>I know that <code>{{somePromise}}</code> will resolve, but <code>{{returnsAPromiseThatResolvesToABoolean()}}</code> seems to cause the same issue.</p>
  
  <p>Any ideas?  I'd expect this to work..</p>