effect-systems/flake.nix

{
  description = "A minimal Haskell flake";

  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixos-21.11";
    flake-utils = {
      url = "github:numtide/flake-utils";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };

  outputs = { self, nixpkgs, flake-utils }:
    flake-utils.lib.eachDefaultSystem (system:
      let
        pkgs = import nixpkgs { inherit system; };

        haskell = {
          ghc = pkgs.haskellPackages.ghc;
          hls = pkgs.haskell-language-server.override {
            supportedGhcVersions = [ "8107" ];
          };
        };
      in
      with pkgs; {
        devShell = mkShell {
          buildInputs = [
            haskell.ghc
            haskell.hls
            gdb
            # GHC depends on LANG so need this package to properly interpret our
            # files with e.g. tasty-discover.
            # https://www.reddit.com/r/Nix/comments/jyczts/nixshell_locale_issue/
            glibcLocales
            haskellPackages.cabal-install
            haskellPackages.ormolu
            haskellPackages.tasty-discover
          ];
        };
      });
}