these 2 derivations will be built:
  /nix/store/anysvn1nca46gmjwhs6mfgqcx7ha8w3h-happy-coder-1.2.5.drv
  /nix/store/sfd2jhnnixg6c6c9p5cxwybf376wqm0w-check-happy-coder.drv