diff --git a/flake.nix b/flake.nix
index a665510..04aa9f8 100644
--- a/flake.nix
+++ b/flake.nix
@@ -15,17 +15,11 @@
       let
         pkgs = nixpkgs.legacyPackages.${system};
 
-        haskellPackages = pkgs.haskell.packages.ghc924;
+        overlay = final: prev: { hcat = final.callCabal2nix "hcat" ./. { }; };
 
-        jailbreakUnbreak = pkg:
-          pkgs.haskell.lib.doJailbreak (pkg.overrideAttrs (_: { meta = { }; }));
-
-        packageName = "hcat";
+        haskellPackages = pkgs.haskell.packages.ghc924.extend overlay;
       in {
-        packages.${packageName} =
-          haskellPackages.callCabal2nix packageName self { };
-
-        packages.default = self.packages.${system}.${packageName};
+        packages.default = haskellPackages.hcat;
 
         apps = {
           # run with: nix run #.hcat
@@ -62,7 +56,7 @@
         devShells.default = haskellPackages.shellFor {
           inherit (self.checks.${system}.pre-commit-check) shellHook;
 
-          packages = _: [ self.packages.${system}.default ];
+          packages = p: [ p.hcat ];
 
           withHoogle = true;