Exactly, between a powerful type system and macros like try!, you're basically rolling on the same level as Haskell and other advanced languages in Rust.
I'd say you should hold off on that claim until Rust errors are composable (RFC #243). I know it's close.
The macros aren't quite up to the job of safely coping with the tangle of different errors that different libraries can return without writing Go-like error handlers yet.
I disagree. The RFC you are citing is effectively just syntax sugar baking the `try!` macro into the language; it doesn't allow you to express anything you couldn't express today with `try!` and closures.