let
  nixos20_03 = {
    "owner" = "NixOS";
    "repo" = "nixpkgs-channels";
    "rev" = "0c0fe6d85b92c4e992e314bd6f9943413af9a309";
    "sha256" = "03q0dzxpd55xmvxzr963hv3nxh57m5d7sgiw5kvhpms1hf8lwd4r";
  };
  nixpkgs20_03_darwin = {
    "owner" = "NixOS";
    "repo" = "nixpkgs-channels";
    "rev" = "0c0fe6d85b92c4e992e314bd6f9943413af9a309";
    "sha256" = "03q0dzxpd55xmvxzr963hv3nxh57m5d7sgiw5kvhpms1hf8lwd4r";
  };
  fetcher = { owner, repo, rev, sha256, ... }: builtins.fetchTarball {
    inherit sha256;
    url = "https://github.com/${owner}/${repo}/tarball/${rev}";
  };
  linuxPackages = fetcher nixos20_03;
  macPackages = fetcher nixpkgs20_03_darwin;
  tmpPackages = (import linuxPackages) {} ;

  onLinux = default: result: if tmpPackages.stdenv.hostPlatform.system == "x86_64-darwin" then default else result;
  onMac = default: result: if tmpPackages.stdenv.hostPlatform.system == "x86_64-darwin" then result else default;
  linuxOrMac = l: m: onLinux m l;

  moz_overlay = import (builtins.fetchTarball "https://github.com/mozilla/nixpkgs-mozilla/archive/master.tar.gz");

  packages = (import (linuxOrMac linuxPackages macPackages)) { overlays = [ moz_overlay ]; };
in
with packages;
let
  rustPlatform = rustChannelOf { date = "2020-08-03"; channel = "stable"; };
  getFromCargo = (import (./. + "/nix/getFromCargo")){ inherit packages rustPlatform; };
in
  getFromCargo {
    name = "docked";
    cargoSha256 = "sha256:0jacm96l1gw9nxwavqi1x4669cg6lzy9hr18zjpwlcyb3qkw9z7f";
  }