Apologies for the slightly vague bug report, but after spending a little while investigating already, I'd like to get an idea of what's actually supposed to work before digging in more depth.

There's code in Documentation.hs and AtPoint.hs that appears to be intended to include haddock docs in the hover information.

However I never see any, even with really trivial test cases. Is this something that is expected to work or is working for others?

One thing I noticed is that there are references in Documentation.hs to things happening when Opt_Haddock or Opt_KeepRawTokenStream are enabled, but I don't see them enabled anywhere.