these 3 derivations will be built:
  /nix/store/cpc0rwbd1ysfp1d1bkdpy7sql46rfh8d-source.drv
  /nix/store/5h7lhfz2l9d7d1fnky52vkvxcb6dxi5y-fx-0.0.13.drv
  /nix/store/6sqvh3ph3vdp97yqbcz8r21n88pi7mff-check-fx.drv