[Haskell-cafe] how to cabal-install so that :doc works?

[Johannes Waldmann]

Dear Cafe -

what do I have to put in my global .cabal/config
in order to make ghci's new :doc command
https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/ghci.html#ghci-cmd-:doc
work after "cabal install <foo>"?

I thought "documentation: True" should do it
but I am invariably getting this:

GHCi, version 8.6.2: http://www.haskell.org/ghc/  :? for help
Prelude> import Ersatz
Prelude Ersatz> :doc solveWith
ghc: Can't find any documentation for Ersatz.Solver.
This is probably because the module was compiled without '-haddock',
but it's also possible that the module contains no documentation.

I do have the .cabal/share/doc/x86_64-linux-ghc-8.6.2/ersatz-0.4.4/html
directory.

The :doc command seems to work for the libraries that come with ghc
(documentation in /opt/ghc/ghc-8.6.2/share/doc/ghc-8.6.2/html/ )

- J.W.