Hi. The entry of EmacsWiki related to Tuareg[1] still refers to "tuareg-imenu-set-imenu".
In Tuareg 2.2.0, this does not work because the file "tuareg-imenu.el" is not part of the package. (I annotated the Wiki page to this effect.)
I think that it would be better if the people maintaining Tuareg had a look at the Wiki page and updated it according to the evolution of Tuareg.
[1] https://www.emacswiki.org/emacs/TuaregMode