these 3 derivations will be built:
  /nix/store/pcwz7dp4ykzpzq9zwgwwvrj0a9c76wxf-source.drv
  /nix/store/dhwb8if51757kni8h03r7pfmjfc5qllz-harmonia-deps-3.3.0.drv
  /nix/store/dp0rwrm28wl3gxz8b14zhblxarzjjig3-harmonia-llvm-cov-3.3.0.drv