Is this php’s bug?

I am reading yii2’s source code right now. I found that this method yii\di\Instance::ensure something werid。

I changed the code as following:

I got output as :

string(15) “yii\di\Instance”

Can anyone explain?


Just now(2016-04-12 15:20:58),I asked Laruence about this questing in qq group.  He answered me that get_calss(null) will return current scope. Then I read the php documetation , It says:

If object is omitted when inside a class, the name of that class is returned.

So, RTFM si right.