Rename a few things.

app/Http/Controllers/Auth/AuthController.php

 <?php namespace App\Http\Controllers\Auth;
 
-use Illuminate\Contracts\Auth\Authenticator;
+use Illuminate\Contracts\Auth\Guard;
 
 use App\Http\Requests\Auth\LoginRequest;
 use App\Http\Requests\Auth\RegisterRequest;
@@ -12,19 +12,19 @@ use App\Http\Requests\Auth\RegisterRequest;
 class AuthController {
 
 	/**
-	 * The authenticator implementation.
+	 * The Guard implementation.
 	 *
-	 * @var Authenticator
+	 * @var Guard
 	 */
 	protected $auth;
 
 	/**
 	 * Create a new authentication controller instance.
 	 *
-	 * @param  Authenticator  $auth
+	 * @param  Guard  $auth
 	 * @return void
 	 */
-	public function __construct(Authenticator $auth)
+	public function __construct(Guard $auth)
 	{
 		$this->auth = $auth;
 	}

app/Http/Middleware/AuthMiddleware.php

 <?php namespace App\Http\Middleware;
 
 use Closure;
-use Illuminate\Contracts\Auth\Authenticator;
+use Illuminate\Contracts\Auth\Guard;
 use Illuminate\Contracts\Routing\Middleware;
 use Illuminate\Contracts\Routing\ResponseFactory;
 
 class AuthMiddleware implements Middleware {
 
 	/**
-	 * The authenticator implementation.
+	 * The Guard implementation.
 	 *
-	 * @var Authenticator
+	 * @var Guard
 	 */
 	protected $auth;
 
@@ -24,11 +24,11 @@ class AuthMiddleware implements Middleware {
 	/**
 	 * Create a new filter instance.
 	 *
-	 * @param  Authenticator  $auth
+	 * @param  Guard  $auth
 	 * @param  ResponseFactory  $response
 	 * @return void
 	 */
-	public function __construct(Authenticator $auth,
+	public function __construct(Guard $auth,
 								ResponseFactory $response)
 	{
 		$this->auth = $auth;

app/Http/Middleware/BasicAuthMiddleware.php

 <?php namespace App\Http\Middleware;
 
 use Closure;
+use Illuminate\Contracts\Auth\Guard;
 use Illuminate\Contracts\Routing\Middleware;
-use Illuminate\Contracts\Auth\Authenticator;
 
 class BasicAuthMiddleware implements Middleware {
 
 	/**
-	 * The authenticator implementation.
+	 * The Guard implementation.
 	 *
-	 * @var Authenticator
+	 * @var Guard
 	 */
 	protected $auth;
 
 	/**
 	 * Create a new filter instance.
 	 *
-	 * @param  Authenticator  $auth
+	 * @param  Guard  $auth
 	 * @return void
 	 */
-	public function __construct(Authenticator $auth)
+	public function __construct(Guard $auth)
 	{
 		$this->auth = $auth;
 	}

app/Http/Middleware/GuestMiddleware.php

 <?php namespace App\Http\Middleware;
 
 use Closure;
+use Illuminate\Contracts\Auth\Guard;
 use Illuminate\Http\RedirectResponse;
-use Illuminate\Contracts\Auth\Authenticator;
 use Illuminate\Contracts\Routing\Middleware;
 
 class GuestMiddleware implements Middleware {
 
 	/**
-	 * The authenticator implementation.
+	 * The Guard implementation.
 	 *
-	 * @var Authenticator
+	 * @var Guard
 	 */
 	protected $auth;
 
 	/**
 	 * Create a new filter instance.
 	 *
-	 * @param  Authenticator  $auth
+	 * @param  Guard  $auth
 	 * @return void
 	 */
-	public function __construct(Authenticator $auth)
+	public function __construct(Guard $auth)
 	{
 		$this->auth = $auth;
 	}