build(nix): drop fenix

we don't need specific/newer versions of rustc. nixpkgs' rust toolchain
has also gotten a lot better

flake.nix

@@ -4,14 +4,6 @@
   inputs = {
     nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";
 
-    fenix = {
-      url = "github:nix-community/fenix";
-      inputs = {
-        nixpkgs.follows = "nixpkgs";
-        rust-analyzer-src.follows = "";
-      };
-    };
-
     treefmt-nix = {
       url = "github:numtide/treefmt-nix";
       inputs.nixpkgs.follows = "nixpkgs";
@@ -22,7 +14,6 @@
     {
       self,
       nixpkgs,
-      fenix,
       treefmt-nix,
     }:
     let
@@ -86,19 +77,8 @@
           pkgs = nixpkgsFor.${system};
           packages' = self.packages.${system};
 
-          mkStatic = pkgs.callPackage ./nix/static.nix {
-            inherit (packages') refraction;
-            fenix = fenix.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/derivation.nix { };

nix/containerize.nix

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

nix/static.nix

@@ -1,39 +1,9 @@
-{
-  lib,
-  pkgsCross,
-  fenix,
-  refraction,
-}:
+{ lib, pkgsCross }:
 let
   crossPlatformFor = with pkgsCross; {
     x86_64 = musl64.pkgsStatic;
     aarch64 = aarch64-multiplatform.pkgsStatic;
   };
-
-  toolchain = fenix.combine (
-    [ fenix.stable.minimalToolchain ]
-    ++ lib.mapAttrsToList (
-      _: pkgs: fenix.targets.${pkgs.stdenv.hostPlatform.rust.rustcTarget}.stable.rust-std
-    ) crossPlatformFor
-  );
-
-  rustPlatformFor = lib.mapAttrs (
-    _: pkgs:
-    pkgs.makeRustPlatform (
-      lib.genAttrs [
-        "cargo"
-        "rustc"
-      ] (_: toolchain)
-    )
-  ) crossPlatformFor;
 in
 { arch }:
-(refraction.override {
-  rustPlatform = rustPlatformFor.${arch};
-  optimizeSize = true;
-}).overrideAttrs
-  (old: {
-    passthru = old.passthru or { } // {
-      inherit toolchain;
-    };
-  })
+crossPlatformFor.${arch}.callPackage ./derivation.nix { optimizeSize = true; }