Axel Rauschmayer (2015-06-03T09:08:13.000Z)
d at domenic.me (2015-06-08T00:06:55.092Z)
https://people.mozilla.org/~jorendorff/es6-draft.html#sec-array.prototype.concat I’m not seeing @@isConcatSpreadable being used as a property key anywhere in the spec.