1. Use Cachix to avoid compilation (optional if you like compiling for 2h)

$ nix-env -iA cachix -f https://cachix.org/api/v1/install
$ cachix use ghcide-nix

2. Install ghcide

Currently available for ghc865, ghc864 and ghc844:

On NixOS

environment.systemPackages = [
  (import (builtins.fetchTarball "https://github.com/cachix/ghcide-nix/tarball/master") {}).ghcide-ghc865
];

With Nix

$ nix-env -iA ghcide-ghc865 -f https://github.com/cachix/ghcide-nix/tarball/master

3. Continue by following upstream instructions

Updating

./update