these 3 derivations will be built:
  /nix/store/2vqr15q66mf0ahxc37vlf8aqhsg5b9q7-source.drv
  /nix/store/5iplk3vjir3p6s40acyffbdibdwms96n-hax-0.6.1.drv
  /nix/store/l2mnapmcmpgrhww3rddaknyrgcw81q49-check-hax.drv