Most of your arguments linked in a comment below are unrelated to the application of metapackages to cargo. Cargo already includes a good portion of the behavio

Most of your arguments linked in a comment below are unrelated to the application of metapackages to cargo. Cargo already includes a good portion of the behaviors found in Stack and Stackage. The idealogical battle of Stack vs Haskell Platform is irrelevant to this proposal. Haskell Platform is a perfectly adequate example to take high-level inspiration for the core of this idea: use Cargo (which is like Stack/Stackage for rust) to help bootstrap Rust libraries when using rustup to install and upgrade (mostly equivalent to `stack setup`).