unison/nix/nixpkgs-overlay.nix

{versions}: final: prev: {
  unison-hls = final.haskell-language-server.override {
    # build with our overridden haskellPackages that have our pinned
    # version of ormolu and hls
    haskellPackages = final.haskell.packages."ghc${versions.ghc}";
    dynamic = true;
    supportedGhcVersions = [versions.ghc];
  };
  haskell =
    prev.haskell
    // {
      packages =
        prev.haskell.packages
        // {
          ghcunison = prev.haskell.packages."ghc${versions.ghc}".extend (hfinal: hprev: let
            inherit (prev.haskell.lib) overrideCabal;
          in {
            # dependency overrides for ormolu 0.5.2.0
            haskell-language-server = let
              p =
                hfinal.callHackageDirect
                {
                  pkg = "haskell-language-server";
                  ver = versions.hls;
                  sha256 = "0kp586yc162raljyd5arsxm5ndcx5zfw9v94v27bkjg7x0hp1s8b";
                }
                {
                  hls-fourmolu-plugin = null;
                  hls-stylish-haskell-plugin = null;
                  hls-hlint-plugin = null;
                  hls-floskell-plugin = null;
                };
              override = drv: {
                doCheck = false;
                configureFlags =
                  (drv.configureFlags or [])
                  ++ [
                    "-f-fourmolu"
                    "-f-stylishhaskell"
                    "-f-hlint"
                    "-f-floskell"
                  ];
              };
            in
              overrideCabal p override;
          });
        };
    };
}