ci3法不'；不适用于PHP5.6版本，但适用于PHP7

我正在使用Codeigniter 3.0.6。我正在本地服务器上开发，我的php版本已经是php7了。它工作得很好。但后来我把它上传到了使用PHP5.6的服务器上。然后我犯了这个错误

这是我的控制器

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

class Student extends CI_Controller {

    public function __construct()
    {
        parent::__construct();
        $this->load->model('m_student','sdb');
        $this->load->model('m_student_profile','sdb_pro');
        $this->load->model('m_student_academic','sdb_aca');
        $this->load->model('m_student_immigration','sdb_imm');
        $this->load->model('m_student_emergency','sdb_eme');
        $this->cname = 'student';
        $this->menu = 'Student';
        $this->fitur = '';
        $this->active_user=get_nama_user();
        $this->active_username=get_username();
        $this->active_privilege=get_hak_akses();
        if(!cek_auth())
        {
            flash_err('Authorization needed.');
            redirect(base_url('auth'));
        }
        if(!cek_fitur('student_list'))
        {
            flash_err("You don't have privilege to use `{$this->menu}` feature.");
            redirect(base_url('dashboard'));
        }
    }

    public function index()
    {
        $this->list();
    }

    public function action($func='', $id=0)
    {
        if(!empty(trim($func)))
        {
            if(!empty($id))
                $this->$func($id);
            else if(empty($id))
                $this->$func();
        }
        else
        {
            flash_err("You don't have permission.");
            redirect(base_url($this->cname));
        }
    }

    public function list()
    {
        $data['title']='Student';
        $data['subtitle']='List';
        $data['active']='student_list';
        $this->fitur = 'List';
        $data['content']='student_list';
        $data['students']=$this->sdb->get_list();
        $this->load->view('template/template',$data);
    }
}

---

这是因为
list
是PHP的保留关键字。在PHP7之前，您不能将它们用作方法名


从PHP7.0.0开始，这些关键字可以作为类、接口和特征的属性名、常量名和方法名，但类不能用作常量名

结果是列表不允许是方法名。我更改了方法名，现在效果很好。尽管我仍然想知道为什么它在php7上工作得很好
 /var/www/simimi/application/controllers/Student.php打开fine look@line 53。你可以发布代码吗？已经添加了@KARTHISRV，但我认为我的控制器很好，因为我的程序在使用PHP7的服务器上运行良好。谢谢。我也意识到了这一点。我很惊慌。
<?php
defined('BASEPATH') OR exit('No direct script access allowed');

class Student extends CI_Controller {

    public function __construct()
    {
        parent::__construct();
        $this->load->model('m_student','sdb');
        $this->load->model('m_student_profile','sdb_pro');
        $this->load->model('m_student_academic','sdb_aca');
        $this->load->model('m_student_immigration','sdb_imm');
        $this->load->model('m_student_emergency','sdb_eme');
        $this->cname = 'student';
        $this->menu = 'Student';
        $this->fitur = '';
        $this->active_user=get_nama_user();
        $this->active_username=get_username();
        $this->active_privilege=get_hak_akses();
        if(!cek_auth())
        {
            flash_err('Authorization needed.');
            redirect(base_url('auth'));
        }
        if(!cek_fitur('student_list'))
        {
            flash_err("You don't have privilege to use `{$this->menu}` feature.");
            redirect(base_url('dashboard'));
        }
    }

    public function index()
    {
        $this->list();
    }

    public function action($func='', $id=0)
    {
        if(!empty(trim($func)))
        {
            if(!empty($id))
                $this->$func($id);
            else if(empty($id))
                $this->$func();
        }
        else
        {
            flash_err("You don't have permission.");
            redirect(base_url($this->cname));
        }
    }

    public function list()
    {
        $data['title']='Student';
        $data['subtitle']='List';
        $data['active']='student_list';
        $this->fitur = 'List';
        $data['content']='student_list';
        $data['students']=$this->sdb->get_list();
        $this->load->view('template/template',$data);
    }
}