diff --git a/flake.nix b/flake.nix
index 931dca7444c16d3586fa64268eb7b0e17c03d38d..b8b70d3a3ffdbbc374744bec390d057026658aab 100644
--- a/flake.nix
+++ b/flake.nix
@@ -67,23 +67,27 @@
     };
   };
   outputs = inputs@{ self, nixpkgs, flake-utils, lint-utils, ... }:
+    flake-utils.lib.eachSystem [ "x86_64-linux" ] (system:
       let
         overlay-ach = final: prev: { all-cabal-hashes = inputs.all-cabal-hashes; };
-        pkgs = import nixpkgs { system = "x86_64-linux"; overlays = [overlay-ach]; };
+        pkgs = import nixpkgs { inherit system; overlays = [ overlay-ach ]; };
         overrides-hp = import ./overlay.nix { inherit inputs pkgs; };
         hp = pkgs.haskell.packages.ghc942.override {
           overrides = overrides-hp;
         };
-        hp' = pkgs.lib.filterAttrs (n: v: v != null
-                                       && builtins.typeOf v == "set"
-                                       && pkgs.lib.hasAttr "type" v
-                                       && v.type == "derivation"
-                                       && v.meta.broken == false) hp;
+        hp' = pkgs.lib.filterAttrs
+          (n: v: v != null
+            && builtins.typeOf v == "set"
+            && pkgs.lib.hasAttr "type" v
+            && v.type == "derivation"
+            && v.meta.broken == false)
+          hp;
       in
       {
-        checks.x86_64-linux = {
+        checks = {
           nixpkgs-fmt = lint-utils.outputs.linters.x86_64-linux.nixpkgs-fmt ./.;
         };
-        packages.x86_64-linux = hp';
-      };
+        overrides = overrides-hp;
+        packages = hp';
+      });
 }
diff --git a/overlay.nix b/overlay.nix
index 0473651e3128f203bea98af02b7f2a7c379ab9b7..4c009b9bbf97715a43ec725edfa4488d2f2bd2de 100644
--- a/overlay.nix
+++ b/overlay.nix
@@ -1,7 +1,7 @@
 { inputs, pkgs }:
 final: prev: with pkgs.haskell.lib; {
 
-  Cabal = prev.callHackage "Cabal" "3.8.1.0" {};
+  Cabal = prev.callHackage "Cabal" "3.8.1.0" { };
 
   ChasingBottoms = prev.callHackage "ChasingBottoms" "1.3.1.12" { };
 
@@ -47,7 +47,7 @@ final: prev: with pkgs.haskell.lib; {
 
   composite-base = doJailbreak (prev.callHackage "composite-base" "0.8.1.0" { });
 
-  composite-dhall = prev.callHackage "composite-dhall" "0.1.0.1" {};
+  composite-dhall = prev.callHackage "composite-dhall" "0.1.0.1" { };
 
   composite-lens-extra = prev.callCabal2nix "composite-lens-extra" inputs.composite-lens-extra { };
 
@@ -91,9 +91,9 @@ final: prev: with pkgs.haskell.lib; {
 
   ghc-tcplugins-extra = final.callCabal2nix "ghc-tcplugins-extra" inputs.ghc-tcplugins-extra { };
 
-  hashable = prev.callHackage "hashable" "1.4.1.0" {};
+  hashable = prev.callHackage "hashable" "1.4.1.0" { };
 
-  hashtables = prev.callHackage "hashtables" "1.3" {};
+  hashtables = prev.callHackage "hashtables" "1.3" { };
 
   hedgehog = dontHaddock (prev.callCabal2nix "hedgehog" (inputs.hedgehog + /hedgehog) { });
 
@@ -147,9 +147,9 @@ final: prev: with pkgs.haskell.lib; {
 
   parallel = doJailbreak (final.callHackage "parallel" "3.2.2.0" { });
 
-  polysemy = dontCheck (prev.callHackage "polysemy" "1.7.1.0" {});
+  polysemy = dontCheck (prev.callHackage "polysemy" "1.7.1.0" { });
 
-  polysemy-time = dontCheck (prev.callHackage "polysemy-time" "0.5.1.0" {});
+  polysemy-time = dontCheck (prev.callHackage "polysemy-time" "0.5.1.0" { });
 
   postgresql-libpq = doJailbreak prev.postgresql-libpq;