I'm not a fan of forcing a left-to-right order in the author's proposed syntax here. Sure the example given by OP is `while let Some((a, a + 1)) = iterator.next

I'm not a fan of forcing a left-to-right order in the author's proposed syntax here. Sure the example given by OP is `while let Some((a, a + 1)) = iterator.next()` but if you want to write `while let Some((b - 1, b)) = iterator.next()`? This is a contrived example because you can switch expressions to make it work. Now what if you want to match a tuple where the first element is the SHA256 hash of the second?