these 3 derivations will be built:
  /nix/store/dfpckjinl7a3ijhlzr9k71im3hrvmzgp-source.drv
  /nix/store/zrxgmp5a8nn8dfjd0kvjmf4crm34l5ya-fx-0.0.12.drv
  /nix/store/pl4qh4yggnvb4g7fwd28rjnmxb40b34s-check-fx.drv