class can't extend from a subproperty
Given this construction
const q = {a: class {}};
class b extends q.a {}
buble will extend class b
from undefined
var q = {a: (function () {
function anonymous () {}
return anonymous;
}())};
var b = (function (undefined) {
function b () {}b.prototype = Object.create( undefined && undefined.prototype );
b.prototype.constructor = b;
return b;
}(undefined));
Tested with buble 0.4.13