more flexible type for foreachE

[matthewleon]

As long as the user knows that foreachE ignores the computation's return value, it seems unfortunate to force upon them the choice of using void or unsafeCoerce.

[paf31]

I'm not sure, actually. I see the appeal, but I think this falls into the same sort of category as Discard.

[matthewleon]

Well, this came up as I was trying to make Iterable instance of Array both simple and efficient, and saw that to do so I had to bring in a dependency for unsafeCoerce. Maybe there is a way out of that, though.