these 3 derivations will be built:
  /nix/store/p9y064prb5086i8mrbhzdirmx3kzwssq-dsh-source.drv
  /nix/store/3fradfmcbp6qwb3m08rchc4yziq79ppx-dsh-0.2.2-rc.3.drv
  /nix/store/1smfr9by4zvzjnapm4pwdxwc1hv3f6sy-check-dsh.drv