看起来像Entrust尚未与Laravel 5.2完全兼容.我在Github上提出了这个问题，其他人也遇到了同样的问题.

Looks like Entrust just isn't fully compatible with Laravel 5.2 yet. I've raised this issue on Github and others are having the same problem.

https://github.com/Zizaco/entrust/issues/472