Ocaml layer fails to load merlin-iedit

Description :octocat:

When adding ocaml layer in dotspacemacs-configuration-layers of my ~/.spacemacs configuration on develop branch, the following error message occures :

Error (use-package): merlin/:init: Cannot open load file: No such file or directory, merlin-iedit

Reproduction guide :beetle:

OPAM and merlin configuration

Example for debian based configurations :

Run following commands

sudo apt install opam
opam init
opam install merlin utop ocp-indent

Configure Spacemacs

Run following commands

cd ~/.emacs.d
git checkout develop
git pull origin develop

Add ocaml layer in dotspacemacs-configuration-layers of ~/.spacemacs file
Start Emacs

Observed behaviour: :eyes: :broken_heart:

Packages seems to be well downloaded but emacs loading fails with the following error message

Error (use-package): merlin/:init: Cannot open load file: No such file or directory, merlin-iedit

Moreover, when editing a Ocaml file, merlin does not seems to work

Expected behaviour: :heart: :smile:

Emacs should launch without an error and merlin should be working as expected.

System Info :computer:

OS: gnu/linux
Emacs: 27.2
Spacemacs: 0.300.0
Spacemacs branch: develop (rev. df15f8cc1)
Graphic display: t
Distribution: spacemacs
Editing style: vim
Completion: helm
Layers:
```
(ocaml)
```
System configuration features: XPM JPEG TIFF GIF PNG RSVG CAIRO SOUND GPM DBUS GSETTINGS GLIB NOTIFY INOTIFY ACL GNUTLS LIBXML2 FREETYPE HARFBUZZ M17N_FLT LIBOTF ZLIB TOOLKIT_SCROLL_BARS GTK3 X11 XDBE XIM MODULES THREADS LIBSYSTEMD JSON PDUMPER LCMS2 GMP
Opam version: 2.0.8
Ocaml version: 4.11.1
Merlin package version: 4.2-411

syl20bnr / spacemacs