关于permission

写多对多关系的时候又发现问题

public function boot(GateContract $gate)
{
parent::registerPolicies($gate);

  foreach($this->getPermissions() as $permission){
  $gate->define($permission->name, function($user) use ($permission){
  return $user->hasRole($permission->roles);
  });
}
}

User里

    
    public function hasRole($role)
    {
        if(is_string($role)){
            return $this->roles->contains('name',$role);
        }
        return !! $role->intersect($this->roles)->count();
    }

然后提示有错误

    FatalErrorException in User.php line 60: Call to a member function intersect() on a non-object

请各位高手指导一下