Effect systems such as Bluefin (my own) and effectful allow you to have multiple possible exception effects in scope without having to cram them all into one type (with some sort of "variant" or "open sum" type). It's a very pleasant way to work!
I haven't had the time to play with Bluefin (I'll get to it eventually!) but I did try out effectful. In the later I've only used the `Fail` effect since most of the time I just want to bail out when some invariant is broken. In my experience these fine-grained errors don't provide much value in practice but I understand the appeal for some.
