Parse error: syntax error, unexpected '::'

Hello, 
I defined constants in Otobil_model.php

PHP Code:

class Otobil_model extends MY_Model
{

    const INDIVIDUAL_TYPE = 'INDIVIDUAL';
    const CORPORATE_TYPE = 'CORPORATE';
} 


Then in Controller I am trying to access these constants:

PHP Code:

class Otobil extends Public_Controller
{
    function __construct()
    {
        parent::__construct();
        $this->load->model('otobil_model');
    }

    public function apply()
    {
        $type = $this->otobil_model::CORPORATE_TYPE;     
    }
} 


I am getting " Parse error: syntax error, unexpected '::' (T_PAAMAYIM_NEKUDOTAYIM) in \application\controllers\Otobil.php on line 36"

Anybody has idea why I am getting this error? 
I already did this in my other projects, but now I am getting this error...

The double colon is for class references (http://php.net/manual/en/language.oop5.p...otayim.php).
You should refer to tyour constant as

Code:

Otobil_model::CORPORATE_TYPE

There was error on loading of otobil_model but instead of showing me that error I got "Parse error: syntax error, unexpected '::'" this error.
When I fixed model loading error this error is gone.

So the result is,  there is nothing to prevent us using this way: $this->otobil_model::CONSTANT_NAME

As it turns out PHP 5.6 does not  support $this->otobil_model::CONSTANT_NAME this type of referencing.
I got this error because of I had a 5.6 PHP installed and when I run it on PHP 7.0 it worked;