build(nix): drop rust-overlay

nixpkgs works well enough and gives us a good buffer in dealing with
compiler regressions

flake.lock

@@ -18,28 +18,7 @@
     },
     "root": {
       "inputs": {
-        "nixpkgs": "nixpkgs",
-        "rust-overlay": "rust-overlay"
-      }
-    },
-    "rust-overlay": {
-      "inputs": {
-        "nixpkgs": [
-          "nixpkgs"
-        ]
-      },
-      "locked": {
-        "lastModified": 1727404165,
-        "narHash": "sha256-kZCiYpQJBZ3kL9QymS88mCxpQwqo8KqvZeHk6LATuY8=",
-        "owner": "oxalica",
-        "repo": "rust-overlay",
-        "rev": "76f0a61e733259e1034dd6523e039d04932ffefc",
-        "type": "github"
-      },
-      "original": {
-        "owner": "oxalica",
-        "repo": "rust-overlay",
-        "type": "github"
+        "nixpkgs": "nixpkgs"
       }
     }
   },

flake.nix

@@ -3,18 +3,12 @@
 
   inputs = {
     nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";
-
-    rust-overlay = {
-      url = "github:oxalica/rust-overlay";
-      inputs.nixpkgs.follows = "nixpkgs";
-    };
   };
 
   outputs =
     {
       self,
       nixpkgs,
-      rust-overlay,
     }:
     let
       inherit (nixpkgs) lib;
@@ -70,19 +64,8 @@
           pkgs = nixpkgsFor.${system};
           packages' = self.packages.${system};
 
-          mkStatic = pkgs.callPackage ./nix/static.nix {
-            inherit (packages') refraction;
-            rust-overlay = rust-overlay.packages.${system};
-          };
-
-          containerize =
-            refraction:
-            pkgs.dockerTools.buildLayeredImage {
-              name = "refraction";
-              tag = "latest-${refraction.passthru.architecture}";
-              config.Cmd = [ (lib.getExe refraction) ];
-              inherit (refraction.passthru) architecture;
-            };
+          mkStatic = pkgs.callPackage ./nix/static.nix { };
+          containerize = pkgs.callPackage ./nix/containerize.nix { };
         in
         {
           refraction = pkgs.callPackage ./nix/package.nix { };

nix/containerize.nix

@@ -0,0 +1,9 @@
+{ lib, dockerTools }:
+refraction:
+
+dockerTools.buildLayeredImage {
+  name = "refraction";
+  tag = "latest-${refraction.passthru.dockerArchitecture}";
+  config.Cmd = [ (lib.getExe refraction) ];
+  architecture = refraction.passthru.dockerArchitecture;
+}

nix/static.nix

@@ -1,37 +1,9 @@
-{
-  lib,
-  refraction,
-  rust-overlay,
-  pkgsCross,
-}:
+{ pkgsCross }:
 let
   crossPlatformFor = with pkgsCross; {
     x86_64 = musl64.pkgsStatic;
     aarch64 = aarch64-multiplatform.pkgsStatic;
   };
-
-  toolchain = rust-overlay.rust.minimal.override {
-    extensions = [ "rust-std" ];
-    targets = lib.mapAttrsToList (_: pkgs: pkgs.stdenv.hostPlatform.rust.rustcTarget) crossPlatformFor;
-  };
-
-  rustPlatformFor = lib.mapAttrs (
-    _: pkgs:
-    pkgs.makeRustPlatform (
-      lib.genAttrs [
-        "cargo"
-        "rustc"
-      ] (_: toolchain)
-    )
-  ) crossPlatformFor;
 in
 { arch }:
-(refraction.override {
-  rustPlatform = rustPlatformFor.${arch};
-  optimizeSize = true;
-}).overrideAttrs
-  (old: {
-    passthru = old.passthru or { } // {
-      inherit toolchain;
-    };
-  })
+crossPlatformFor.${arch}.callPackage ./package.nix { optimizeSize = true; }