return to ocaml overlay

flake.nix

@@ -1,9 +1,14 @@
 {
   inputs = {
-    nixpkgs.url = "github:nixOS/nixpkgs";
+    nixpkgs.url = "github:nix-ocaml/nix-overlays";
     flake-utils.url = "github:numtide/flake-utils";
   };
 
+  nixConfig = {
+    extra-substituters = "https://anmonteiro.nix-cache.workers.dev";
+    extra-trusted-public-keys = "ocaml.nix-cache.com-1:/xI2h2+56rwFfKyyFVbkJSeGqSIYMC/Je+7XXqGKDIY=";
+  };
+
   outputs = {
     self,
     nixpkgs,
@@ -13,9 +18,10 @@
   in
     flake-utils.lib.eachDefaultSystem (
       system: let
-        pkgs = import nixpkgs {
-          inherit system;
-        };
+        pkgs = nixpkgs.legacyPackages.${system};
+        # import nixpkgs {
+        #   inherit system;
+        # };
         inherit (pkgs) mkShell ocamlPackages;
         inherit
           (ocamlPackages)
@@ -94,12 +100,12 @@
       }
     )
     // {
-      nixosModules.culr = import ./nix/module.nix {culrOverlay = self.overlays.culr;};
+      nixosModules.culr = import ./nix/module.nix {overlays = [self.overlays.culr self.inputs.nixpkgs.overlays.default];};
 
       overlays.culr = final: prev: let
         ocaml-deps = let
           inherit
-            (prev.ocamlPackages)
+            (final.ocamlPackages)
             dune_3
             ocaml
             angstrom