> It's easy to read, isn't? No, it's verbose and ugly. Easy to read would be something like: fn try_join(a:A:Future<E||AR>,b:B:Future<E||BR>) -> impl Future

> It's easy to read, isn't? No, it's verbose and ugly. Easy to read would be something like: fn try_join(a:A:Future<E||AR>,b:B:Future<E||BR>) -> impl Future<E||(AR,BR)> (Rounding to the nearest Rust-like syntax where appropriate and borrowing `type (||) = Either` from Haskell.)