root is not defined

[iamvdo]

I have this strange error with many module. See stacktrace:

"ReferenceError: root is not defined
    at Declaration.style (:21023:12)
    at Declaration.stringify (:20632:22)
    at Rule.stringifyContent (:20342:23)
    at Rule.stringifyBlock (:20363:10)
    at Rule.stringify (:21833:10)
    at Root.stringifyContent (:20338:23)
    at Root.stringify (:21788:10)
    at Root.toString (:20976:10)
    at MapGenerator.generate (:20916:25)
    at Result.stringify (:21756:46)"

Lines no matter here, it's in node.js line 136 root = this;. If I write if (!root) {var root = this;}, it's OK. Very weird.
It's OK (no error) with AutoPrefixer, postcss-vars, but NOK (error) with pixrem, pleeease-filters.

If you have an idea, it'll be good. Try to find where the problem is btw.

[iamvdo]

Firefox has a slightly better error: "ReferenceError: assignment to undeclared variable root".
So is there a reason why it's root = this and not var root = this ?

Plus, the problem appears only in browser, not programmatically, so it feels more weird to me.

[ai]

Yeap. I fix this issue, when I migrate from Traceur.

It was a ES6 migration issue, that wasn’t found by tests :(.

[ai]

Fix is pushed 1e2c522