these 3 derivations will be built:
  /nix/store/sl6zlgs02cr8w94qs570p36rl9gd3zrf-source.drv
  /nix/store/hwdiz1zzmxm8h7a44g1z1jg90yx7h909-semble-0.6.2.drv
  /nix/store/20dm3p9ybgpnl3swnbd85jkcg7w5v7sw-check-semble.drv
warning: SQLite database '/nix/var/nix/db/db.sqlite' is busy