[ANN] The OCaml 4.13 preview for Merlin is now available


Over the past previous OCaml releases the release-readiness team tried its best to make most packages, and especially core OCaml packages (dune, merlin, ppxlib, …) available day one so people can have the smoothest transition possible to the new compiler release.

Today I’m announcing that merlin (arguably the trickiest core tool to port to new releases, and the most indispensable) is now available to install for early adopters of OCaml 4.13.

To install the latest OCaml 4.13 beta together with Merlin simply call:

$ opam switch create 4.13 --formula='"ocaml-base-compiler" {>= "4.13" & < "4.14"}'
$ opam install merlin

The package is still an early preview. If you encounter any problems while using merlin, please feel free to report it directly in https://github.com/ocaml/merlin/pull/1381

All of the OCaml core packages (with the exception of ocaml-lsp, hopefully soon) should be available out-of-the-box. If some packages aren’t available yet, opam-alpha-repository should have you covered:

$ opam remote add alpha git://github.com/kit-ty-kate/opam-alpha-repository.git

If you have any questions or remarks feel free to ask them here.


(Linux box)


$ opam switch create 4.13 --formula='"ocaml-base-compiler" {>= "4.13" & < "4.14"}'

$ eval $(opam env --switch=4.13)

$ opam install merlin
[ERROR] Package conflict!
  * No agreement on the version of ocaml:
    - (invariant) → ocaml-base-compiler >= 4.13.0~ → ocaml = 4.13.0
    - merlin → ocaml < 4.05
    You can temporarily relax the switch invariant with `--update-invariant'

No solution found, exiting

Any hint?

uhh, looks like the default opam.ocaml.org index updater is still experiencing issues.
With this temporary fix it should be alright Package index on opam.ocaml.org outdated? - #2 by rjbou

Sorry about that

OK with the temporary fix.
Thank you.

1 Like

It’s back! Sorry for the inconvenience.

The OCaml 4.13 preview for ocaml-lsp-server is now available as well.

To install it along with the OCaml 4.13 rc, please refer to the first post.

If you encounter any problems while using ocaml-lsp-server, please feel free to report it directly in Update to ocaml 4.13 by ulugbekna · Pull Request #506 · ocaml/ocaml-lsp · GitHub