That's surprising, because my understanding was that per-iteration binding was ONLY supposed to happen for c-style for-loops (at least, that's how the Firefox bug was clearly written), per conversations I had with @dherman. Maybe he can clarify?

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**Side note:**, not sure if you realized, but your `for-in` isn't actually iterating over the values of the `[1,2,3]` array, but only the indexes of it, which is why it prints `0  1  2`. :)