build: format nix files with nixfmt, update nix flakes

flake.nix

@@ -3,20 +3,33 @@
 
   inputs.nixpkgs.url = "github:nix-ocaml/nix-overlays";
 
-  outputs = { self, nixpkgs }:
+  outputs =
+    { self, nixpkgs }:
     let
-      forAllSystems = f: nixpkgs.lib.genAttrs nixpkgs.lib.systems.flakeExposed (system:
-        let
-          pkgs = nixpkgs.legacyPackages.${system}.extend (self: super: {
-            ocamlPackages = super.ocaml-ng.ocamlPackages_5_4;
-          });
-        in
-        f pkgs);
+      forAllSystems =
+        f:
+        nixpkgs.lib.genAttrs nixpkgs.lib.systems.flakeExposed (
+          system:
+          let
+            pkgs = nixpkgs.legacyPackages.${system}.extend (
+              self: super: {
+                ocamlPackages = super.ocaml-ng.ocamlPackages_5_4;
+              }
+            );
+          in
+          f pkgs
+        );
     in
     {
-      packages = forAllSystems (pkgs:
-        let packages = pkgs.callPackage ./nix { }; in
-        { inherit packages; default = packages.reason; }
+      packages = forAllSystems (
+        pkgs:
+        let
+          packages = pkgs.callPackage ./nix { };
+        in
+        {
+          inherit packages;
+          default = packages.reason;
+        }
       );
 
       devShells = forAllSystems (pkgs: {

nix/ci.nix

@@ -5,32 +5,12 @@ let
   pkgs =
     let
       src = fetchGit {
-        url = with lock.nodes.nixpkgs.locked;"https://github.com/${owner}/${repo}";
+        url = with lock.nodes.nixpkgs.locked; "https://github.com/${owner}/${repo}";
         inherit (lock.nodes.nixpkgs.locked) rev;
         allRefs = true;
       };
     in
-    import src {
-      extraOverlays = [
-        (self: super: {
-          ocamlPackages = super.ocaml-ng."ocamlPackages_${ocamlVersion}".overrideScope (oself: osuper: {
-            pp = osuper.pp.overrideAttrs (_: {
-              doCheck = false;
-            });
-            ppxlib = osuper.ppxlib.overrideAttrs (_: {
-              src =
-                if super.lib.versionOlder "5.4" osuper.ocaml.version then
-                  osuper.ppxlib.src
-                else
-                  builtins.fetchurl {
-                    url = "https://github.com/ocaml-ppx/ppxlib/releases/download/0.36.0/ppxlib-0.36.0.tbz";
-                    sha256 = "0d54j19vi1khzmw0ffngs8xzjjq07n20q49h85hhhcf52k71pfjs";
-                  };
-            });
-          });
-        })
-      ];
-    };
+    import src { };
 in
 
 pkgs.callPackage ./. { doCheck = true; }

nix/default.nix

@@ -1,12 +1,18 @@
-{ lib, ocamlPackages, doCheck ? false }:
+{
+  lib,
+  ocamlPackages,
+  doCheck ? false,
+}:
 
 rec {
   reason = ocamlPackages.buildDunePackage {
     pname = "reason";
     version = "0.0.1-dev";
 
     src =
-      let fs = lib.fileset; in
+      let
+        fs = lib.fileset;
+      in
       fs.toSource {
         root = ./..;
         fileset = fs.unions [
@@ -21,7 +27,10 @@ rec {
 
     inherit doCheck;
 
-    nativeBuildInputs = with ocamlPackages; [ cppo menhir ];
+    nativeBuildInputs = with ocamlPackages; [
+      cppo
+      menhir
+    ];
     propagatedBuildInputs = with ocamlPackages; [
       cmdliner
       merlin-extend
@@ -39,7 +48,9 @@ rec {
     version = "0.0.1-dev";
 
     src =
-      let fs = lib.fileset; in
+      let
+        fs = lib.fileset;
+      in
       fs.toSource {
         root = ./..;
         fileset = fs.unions [
@@ -55,6 +66,9 @@ rec {
     inherit doCheck;
 
     nativeBuildInputs = with ocamlPackages; [ cppo ];
-    propagatedBuildInputs = [ reason ocamlPackages.utop ];
+    propagatedBuildInputs = [
+      reason
+      ocamlPackages.utop
+    ];
   };
 }

nix/shell.nix

@@ -1,10 +1,11 @@
-{ mkShell
-, ocamlPackages
-, reason
-, cacert
-, curl
-, git
-, release-mode ? false
+{
+  mkShell,
+  ocamlPackages,
+  reason,
+  cacert,
+  curl,
+  git,
+  release-mode ? false,
 }:
 
 mkShell {
@@ -16,5 +17,16 @@ mkShell {
     ocamlformat
   ];
   buildInputs =
-    with ocamlPackages; (if release-mode then [ cacert curl dune-release git ] else [ ]);
+    with ocamlPackages;
+    (
+      if release-mode then
+        [
+          cacert
+          curl
+          dune-release
+          git
+        ]
+      else
+        [ ]
+    );
 }