Merge pull request #5 from srid/magthe

Improvements from @magthe's blog post

.envrc

@@ -0,0 +1 @@
+use flake

.gitignore

@@ -23,3 +23,6 @@ cabal.project.local~
 .ghc.environment.*
 result
 result-*
+
+# direnv
+.direnv

flake.lock

@@ -33,17 +33,17 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1645013224,
-        "narHash": "sha256-b7OEC8vwzJv3rsz9pwnTX2LQDkeOWz2DbKypkVvNHXc=",
+        "lastModified": 1647350163,
+        "narHash": "sha256-OcMI+PFEHTONthXuEQNddt16Ml7qGvanL3x8QOl2Aao=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "b66b39216b1fef2d8c33cc7a5c72d8da80b79970",
+        "rev": "3eb07eeafb52bcbf02ce800f032f18d666a9498d",
         "type": "github"
       },
       "original": {
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "b66b39216b1fef2d8c33cc7a5c72d8da80b79970",
+        "rev": "3eb07eeafb52bcbf02ce800f032f18d666a9498d",
         "type": "github"
       }
     },

flake.nix

@@ -1,7 +1,7 @@
 {
   description = "haskell-template's description";
   inputs = {
-    nixpkgs.url = "github:nixos/nixpkgs/b66b39216b1fef2d8c33cc7a5c72d8da80b79970";
+    nixpkgs.url = "github:nixos/nixpkgs/3eb07eeafb52bcbf02ce800f032f18d666a9498d";
     flake-utils.url = "github:numtide/flake-utils";
     flake-utils.inputs.nixpkgs.follows = "nixpkgs";
     flake-compat.url = "github:edolstra/flake-compat";
@@ -11,12 +11,13 @@
   outputs = inputs@{ self, nixpkgs, flake-utils, ... }:
     flake-utils.lib.eachDefaultSystem (system:
       let
-        overlays = [ ];
-        pkgs =
-          import nixpkgs { inherit system overlays; config.allowBroken = true; };
+        # Because: https://zimbatm.com/notes/1000-instances-of-nixpkgs
+        pkgs = nixpkgs.legacyPackages.${system};
+
         # Change GHC version here. To get the appropriate value, run:
         #   nix-env -f "<nixpkgs>" -qaP -A haskell.compiler
         hp = pkgs.haskellPackages; # pkgs.haskell.packages.ghc921;
+
         project = returnShellEnv:
           hp.developPackage {
             inherit returnShellEnv;
@@ -31,13 +32,14 @@
               # Assumes that you have the 'NanoID' flake input defined.
             };
             modifier = drv:
-              pkgs.haskell.lib.addBuildTools drv (with hp; [
+              pkgs.haskell.lib.addBuildTools drv (with hp; pkgs.lib.lists.optionals returnShellEnv [
                 # Specify your build/dev dependencies here. 
                 cabal-fmt
                 cabal-install
                 ghcid
                 haskell-language-server
                 ormolu
+                hlint
                 pkgs.nixpkgs-fmt
               ]);
           };