fenix:

let
  file = ./rust-toolchain.toml;
  sha256 = "+syqAd2kX8KVa8/U2gz3blIQTTsYYt3U63xBWaGOSc8=";
in

rec {
  fromFile = { buildSystem }: fenix.packages.${buildSystem}.fromToolchainFile {
    inherit file sha256;
  };

  toRustTarget = target: {
    x86_64-w64-mingw32 = "x86_64-pc-windows-gnu";
  }.${target} or target;

  fromTarget = { lib, targetSystem }:
    let
      target = toRustTarget targetSystem;
      name = (lib.importTOML file).toolchain.channel;
      toolchain = fenix.fromToolchainName { inherit name sha256; };
      targetToolchain = fenix.targets.${target}.fromToolchainName { inherit name sha256; };
    in
    fenix.combine [
      toolchain.rustc
      toolchain.cargo
      targetToolchain.rust-std
    ];
}