these 3 derivations will be built:
  /nix/store/1yxlgfcy3b0xz6f2qwhnbp02w5bxc714-source.drv
  /nix/store/by6wd9adb54il3ai7dqll87jmi5y9i5n-harmonia-deps-3.3.0.drv
  /nix/store/pfzzki8qvz54v5flchnbi4iya5b5j3zq-harmonia-llvm-cov-3.3.0.drv