title: Behaviour bindToController in child scope versus isolated scope
body: <p>I was playing around with the <code>bindToController</code> option for directives. I stumbled upon a seemingly strange difference between the behaviour using a child scope compared to an isolated scope. When I use an isolated scope, an new scope is created for the directive, but changes to the bound controller attributes are forwarded to the parent scope. Yet when I use a child scope instead, my example breaks. (Using <code>bindToController</code> using child scopes should be allowed according to <a href="http://blog.thoughtram.io/angularjs/2015/01/02/exploring-angular-1.3-bindToController.html#improvements-in-14" rel="noreferrer">http://blog.thoughtram.io/angularjs/2015/01/02/exploring-angular-1.3-bindToController.html#improvements-in-14</a> )</p>
  
  <p>The code:</p>
  
  <pre><code>{
      restrict: 'E',
      scope: {},
      controller: 'FooDirCtrl',
      controllerAs: 'vm',
      bindToController: {
          name: '='
      },
      template: '&lt;div&gt;&lt;input ng-model="vm.name"&gt;&lt;/div&gt;'
  };
  </code></pre>
  
  <p>Working demo <a href="https://jsfiddle.net/tthtznn2/" rel="noreferrer">https://jsfiddle.net/tthtznn2/</a></p>
  
  <p>The version using a child scope:</p>
  
  <pre><code>{
      restrict: 'E',
      scope: true,
      controller: 'FooDirCtrl',
      controllerAs: 'vm',
      bindToController: {
          name: '='
      },
      template: '&lt;div&gt;&lt;input ng-model="vm.name"&gt;&lt;/div&gt;'
  };
  </code></pre>
  
  <p>Demo: <a href="http://jsfiddle.net/ydLd1e00/" rel="noreferrer">http://jsfiddle.net/ydLd1e00/</a></p>
  
  <p>The changes to name are forwarded to the child scope, but not to the parent scope. This in contrast to binding to an isolated scope. Why is this?</p>