Using ghcid on nixos

Posted on March 22, 2020

While using nixos, I had an issue with running ghcid on my local machine.

It would break as it was unable to find a ghc compiler.

At first in an attempt to hack it into working, I installed ghcid and ghc at the toplevel in my configuration.nix

However, after thinking carefully, I realized that different projects might have different ghc versions tagged and hence I shouldn’t install these tools system-wide.

Hence removed these installs and created a simple haskell-env.nix file which you can find here:

which you can run by:


nix-shell haskell-env.nix

I then specified the appropriate ghc compiler (Just used the latest one in nixpkgs) in my stack.yaml.

What this achieves is isolating the tools to each project’s ghc version, avoiding a project dependence on the system’s ghc and ghcid.