Right, but I can think of a few cases where one might want to be generic over effect systems; especially in library code. For example, you could have a parsing library that accepts both blocking and non-blocking I/O streams. You need a Map/Then trait in order to express that generically.
Re:Monads and GATs in Nightly Rust
by burntsushi on Friday December 11, 2020 @09:06PM
(#25394610)
I didn't say there weren't any use cases. Of course there are use cases.
I'm not even taking a side here in this thread (although I have advocated against functors/monads in the past). I'm saying that your comment is missing the point of folks who are skeptical of things like functors and monads.
I think this kind of "you've already used functors or monads, they are just scary names" retort is really missing the point of what folks are complaining about.