Use flake.nix dev shell

Author: thomasjm

flake.lock

@@ -5,7 +5,7 @@
     url = "github:hercules-ci/gitignore.nix";
     inputs.nixpkgs.follows = "nixpkgs";
   };
-  inputs.nixpkgs.url = "github:NixOS/nixpkgs/release-24.11";
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/release-25.05";
   inputs.nixpkgsMaster.url = "github:NixOS/nixpkgs/master";
 
   outputs = { self, flake-utils, gitignore, haskellNix, nixpkgs, nixpkgsMaster }:
@@ -49,7 +49,12 @@
           devShells = {
             default = pkgs.mkShell {
               NIX_PATH = "nixpkgs=${pkgsMaster.path}";
-              buildInputs = [];
+              buildInputs = with pkgs; [
+                haskell.compiler.ghc9122
+
+                pcre
+                zlib
+              ];
             };
           };
 

flake.nix

@@ -1,14 +1,12 @@
-resolver: nightly-2025-05-28
-compiler: ghc-9.12.2
+resolver: nightly-2025-12-22
 
 packages:
 - .
 
 nix:
-  pure: false
-  packages:
-  - zlib
-  - pcre
+  enable: false
+
+system-ghc: true
 
 extra-deps:
 # - language-rust-0.2.0.27

stack.yaml

@@ -6,7 +6,7 @@
 packages: []
 snapshots:
 - completed:
-    sha256: e9b93acfb8aaf8ae4869050506553a963a8adba95748cd60356f9ffe64f03345
-    size: 712232
-    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/nightly/2025/5/28.yaml
-  original: nightly-2025-05-28
+    sha256: 0d762ad5bc0b99b04d9e0b4c4cc05cfea05b3c2c0168de242258cb3e41aedd96
+    size: 714960
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/nightly/2025/12/22.yaml
+  original: nightly-2025-12-22