controller error di bagian construct

bagian controller

<?php
defined('BASEPATH') or exit('No direct script access allowed');

class Login extends CI_Controller
{
    function __construct()
    {
        parent::__construct();
        //validasi jika user belum login
        $this->data['CI'] = &get_instance();
        $this->load->helper(array('form', 'url'));
        $this->load->model('M_login');
    }
    /**
     * Index Page for this controller.
     *
     * Maps to the following URL
     *      http://example.com/index.php/welcome
     *  - or -
     *      http://example.com/index.php/welcome/index
     *  - or -
     * Since this controller is set as the default controller in
     * config/routes.php, it's displayed at http://example.com/
     *
     * So any other public methods not prefixed with an underscore will
     * map to /index.php/welcome/<method_name>
     * @see https://codeigniter.com/user_guide/general/urls.html
     */
    public function index()
    {
        $this->data['title_web'] = 'Login | Sistem Informasi Perpustakaan';
        $this->load->view('login_view', $this->data);
    }

    public function auth()
    {
        $user = htmlspecialchars($this->input->post('user', TRUE), ENT_QUOTES);
        $pass = htmlspecialchars($this->input->post('pass', TRUE), ENT_QUOTES);
        // auth
        $proses_login = $this->db->query("SELECT * FROM tbl_login WHERE user='$user' AND pass = md5('$pass')");
        $row = $proses_login->num_rows();
        if ($row > 0) {
            $hasil_login = $proses_login->row_array();

            // create session
            $this->session->set_userdata('masuk_perpus', TRUE);
            $this->session->set_userdata('level', $hasil_login['level']);
            $this->session->set_userdata('ses_id', $hasil_login['id_login']);
            $this->session->set_userdata('anggota_id', $hasil_login['anggota_id']);

            echo '<script>window.location="' . base_url() . 'dashboard";</script>';
        } else {

            echo '<script>alert("Login Gagal, Periksa Kembali Username dan Password Anda");
            window.location="' . base_url() . '"</script>';
        }
    }

    public function logout()
    {
        $this->session->sess_destroy();
        echo '<script>window.location="' . base_url() . '";</script>';
    }
}

bagian module login

<?php
if(! defined('BASEPATH')) exit('No direct script acess allowed');

class M_Login extends CI_Model
{

  function GET_LOGIN($user,$pass)
  {
      $row = $this->db->query("SELECT * FROM tbl_login WHERE user ='$user' AND pass = '$pass'");
      return $row;
  }

  function insertTable($table_name,$data)
  {
   $tambah = $this->db->insert($table_name,$data);
   return $tambah;
  }

}
?>