these 5 derivations will be built:
  /nix/store/afbrc98x28kfpcvfxbm4k8xj59qfkp06-Cargo.toml.drv
  /nix/store/qd2sipp62gln0mp03vajwlqw14dlws6q-Cargo.toml.drv
  /nix/store/xj1dfyik6h2f6ckmxpww0mzvg5rnh4mw-source.drv
  /nix/store/186byaald8ca8xxs12wn67yf3w50dw7q-harmonia-deps-3.2.0.drv
  /nix/store/qll64d207grqcvgk32b2pnj6x11z4nr4-harmonia-llvm-cov-3.2.0.drv