Integrating Haddock into the GHC tree
I had this discussion with multiple people in private but I'd like to have it publicly as well.
For people outside of the GHC project, having Haddock on GitHub has the advantage of having it hosted on a well-known platform (ease of login), but we also get few "absolute newcomer" contributions, which makes me question the benefits of having Haddock's tree outside of the GHC tree. The jumps through hoops that we have to do with the gitlab mirror and the submodule seem less and less worth it, especially when GHC distributes its own version that doesn't have an equivalent in the GitHub tree.
Most languages that have a documentation tool also have its code living with the compiler (from the top of my head I can think of Elixir, Rust, Python), and we can certainly simplify things a great deal if we remove indirections.