Understanding how warnings on unused functions work

[Razetime]

This message is related to a feature in the futhark compiler
<https://github.com/diku-dk/futhark/issues/550>, which is a language with a
similar module system.

I am trying to create a tool to detect unused top-level functions in
Futhark, and I have been looking in the ghc codebase to find out how it
does so. So far I have found these areas:

   1. warning flag
   <https://gitlab.haskell.org/ghc/ghc/-/blob/master/compiler/GHC/Driver/Flags.hs#L556-557>
   2. WarnUnusedTopBinds
   <https://gitlab.haskell.org/ghc/ghc/-/blob/master/compiler/GHC/Rename/Utils.hs#L355>

The project is a bit too big for my machine to take, so HLS is not helping
me with finding where the computation of unused bindings (specifically
functions) is done.
I would like some help with finding where ghc does this computation, and
maybe some help with the naming conventions of the code.

Thanks in advance.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.haskell.org/pipermail/ghc-devs/attachments/20230314/fa79d6fd/attachment.html>