Inside the tree there are rust and rust-bin, and cargo. cargo-bin is missing. Reproducible: Always
In addition virtual packages would make much sense: virtual/rust -> rust or rust-bin -> virtual/cargo virtual/cargo -> cargo or cargo-bin This way e.g. firefox can depend on virtual/rust and cargo and rust can be used either both self-compiled, both pre-compiled or in a mixed way.
closing as obsolete, package was available for some time, but we decided to no longer provide separate cargo due to various complications. it's just part of dev-lang/rust and dev-lang/rust-bin