Configuration needed for Haskell IDE Environment

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I’m trying to replicate the configuration from this article on a NixOS:

That’s, I’m trying to use hie on neovim, through coc.nvim, with NixOS as operating system. For now, I want it to work for a project which uses GHC 8.6.5 through Stack.

So far I’ve been able to:

  • Install hie version for GHC 8.6.5:
let
  all-hies = import (fetchTarball "https://github.com/infinisil/all-hies/tarball/master") {};
in
  {
    environment.systemPackages = with pkgs; [
      (all-hies.selection { selector = p: { inherit (p) ghc865; }; })
    ];
  }
  • Install neovim 4.x to have floating window feauture, which is only available in master, as far as I know:
let
  nixPkgsMaster = import (fetchTarball "https://github.com/NixOS/nixpkgs/tarball/master") {};
in
  {
    environment.systemPackages = with pkgs; [
      nixPkgsMaster.neovim
    ];
  }

  • I configured coc.nvim to use hie. I think everything is correct from this side.

  • I found that having hie for GHC 8.6.5 was not enough and that I had to install manually the compiler for 8.6.5. I think it is needed in NixOS. If I’m wrong, please, tell me. So, I added the following in environment.systemPackages:

haskell.compiler.ghc865
  • Besides, I have following haskell tools:
haskellPackages.hlint
haskellPackages.apply-refact
haskellPackages.hindent

With all of that, hie is somehow working on neovim, but there are a lot of things missing.

For example, one thing that is working is :call CocAction('format'). It also points me to some hlint warnings underlying their lines.

However, there are a lot of functionalities missing.

  • Autocompletion is anything but intellisense.
  • I can’t quickfix hlint warnings. It says [coc.nvim] No quickfix action available.
  • Trying to rename returns me [coc.nvim] Error on 'rename': rename: "HaRe: file not loaded for refactoring"
  • It gives me no type information when I press K on a word (being K mapped as coc.nvim suggests)

I think that my NixOS configuration is the culprit here, because I’m not too experienced with it and I see it needs to be very specific when configuring haskell. I’m wondering if I’m missing some extra haskell package. I tried with haskell.packages.ghc865.hoogle hoping it would make a difference in showing me types or documentation, but no luck here.

Thanks for any insight you can give me.

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