this derivation will be built:
  /nix/store/wwx0kygm556g1777xcdcg3h6wdw9cy2d-nix-shell.drv
building '/nix/store/wwx0kygm556g1777xcdcg3h6wdw9cy2d-nix-shell.drv'
nix-shell> Running phase: buildPhase