使用HMVC时load library

甲骨文

Module ->Build
Class->Tool
library在 application/library/marketing/Discount.php

代码如下：
class Build_Tool_module extends CI_Controller
{

    // 在不使用HMVC的情况下是OK的
    public function discount()
    {
        $this->load->library('marketing/Discount');

var_dump($this->discount); // null
        print_r($this->discount->buildTool());
    }
}

错误：
A PHP Error was encountered

Severity: Notice

Message: Trying to get property of non-object

Filename: core/MY_Loader.php

Line Number: 938

// 错误已修改好了

class Build_Tool_module extends CI_Module
{

    // 在不使用HMVC的情况下是OK的
    public function discount()
    {
        $this->load->library('marketing/Discount');

var_dump($this->discount); // null
        print_r($this->discount->buildTool());
    }
}

Hex

discount 改小写