[Tloewald]

It's more of a surprising non-leak caused by clever GC that is insufficiently clever to handle pathological code. Interesting explanation, but yet another reason to be very careful of setInterval.

[ufo]

Not only setInterval though. This sort of leak can also show up if the closure is a DOM event handler or is otherwise exposed.

[Tloewald]

It can show up anywhere — and in fact event handlers are a major source of leaks in general — but the point is that the leak doesn't occur as frequently as you might expect not that it occurs.