class A extends null {}; class B extends null { constructor() { debug(this instanceof B && !(this instanceof Object)); } }; // should be true; Following discussions cover this issue: https://github.com/tc39/ecma262/issues/543 Spec https://github.com/tc39/ecma262/blob/703238399d339ceb7f894f4733626f601d42d05e/workingdocs/ES6-super-construct%3Dproposal.md - Last sentance and And https://github.com/tc39/ecma262/issues/22
Oh, I was so slow in adding new issue, so need to close duplicate *** This bug has been marked as a duplicate of bug 160417 ***