the trait IntoValue is not implemented for Result<(), String>

[mimoo]

error[E0277]: the trait bound `Result<(), String>: IntoValue` is not satisfied
  --> src/lib.rs:46:1
   |
46 | #[ocaml::func]
   | ^^^^^^^^^^^^^^ the trait `IntoValue` is not implemented for `Result<(), String>`
   |
   = help: the following other types implement trait `IntoValue`:
             Result<T, E>
             Result<T, ocaml::Error>
   = note: this error originates in the attribute macro `ocaml::func` (in Nightly builds, run with -Z macro-backtrace for more info)

I would have thought, following the doc, that any Result<T, E> would be converted to (t, e) result in OCaml as long as both T and E implemented the needed types, but using String as error doesn't seem to work.

in the Rust doc I see that IntoValue is only implemented if E = ocaml::Error:

I also can't find tests on that, I'm guessing the book is wrong?

EDIT: I see an implementation of ToValue which is weird as I thought ToValue was not a thing anymore... in any case I can't implement IntoValue on Result myself due to the orphan rule

[zshipko]

The book documents the 1.0.0-beta release, which switches back to ToValue and implements ToValue for Result - the latest non-beta doesn't.

[mimoo]

oh I see :)) time for a non-beta release :D ?

[zshipko]

haha yes, the goal is to release 1.0.0 when the ocaml5 branch is merged. that should be relatively soon!