The docs show:

<?php namespace App\Http\Controllers;

use Auth;
use Illuminate\Routing\Controller;

class AuthController extends Controller {

    /**
     * Handle an authentication attempt.
     *
     * @return Response
     */
    public function authenticate()
    {
        if (Auth::attempt(['email' => $email, 'password' => $password]))
        {
            return redirect()->intended('dashboard');
        }
    }

}

Example auth controller that comes with L5 shows:

<?php namespace App\Http\Controllers\Auth;
use App\Http\Controllers\Controller;
use Illuminate\Contracts\Auth\Guard;
use Illuminate\Contracts\Auth\Registrar;
use Illuminate\Foundation\Auth\AuthenticatesAndRegistersUsers;
class AuthController extends Controller {
/*
|--------------------------------------------------------------------------
| Registration & Login Controller
|--------------------------------------------------------------------------
|
| This controller handles the registration of new users, as well as the
| authentication of existing users. By default, this controller uses
| a simple trait to add these behaviors. Why don't you explore it?
|
*/
use AuthenticatesAndRegistersUsers;
/**
* Create a new authentication controller instance.
*
* @param \Illuminate\Contracts\Auth\Guard $auth
* @param \Illuminate\Contracts\Auth\Registrar $registrar
* @return void
*/
public function __construct(Guard $auth, Registrar $registrar)
{
$this->auth = $auth;
$this->registrar = $registrar;
$this->middleware('guest', ['except' => 'getLogout']);
}
}

Why isn't docs up to date by now?