Okay, changing the requirement from "fix all of rustc and rustdoc" to "fix all of rustc and rustdoc and cargo" is not that a big deal. Still, it is a noticable change, because Cargo is in the different repository.
But cargotest includes projects other than Cargo, which is just Iron at the moment. As I understand, more will be added in the future. Is the intention that landing new lint should be blocked on fixing Iron and additional crates to be determined in the future?