The create_world_atom function could omit this atom if the system atom is unslotted: > # emerge -avn gcc > > These are the packages that would be merged, in order: > > Calculating dependencies... done! > > Total: 0 packages, Size of downloads: 0 KiB > > > * sys-devel/gcc > > Would you like to add these packages to your world favorites? [Yes/No]