[lucian1900]

I like the way it's done in Clojure, where Leiningen projects declare Clojure itself as a dependency, with an explicit version.

[nuxlli]

Also not sure I like the idea of ​​having it for the. Besides the extra work of maintaining it may imply, I believe that leaving it in the hands of the isolation system dependencies over worked.

[munificent]

The package manager I work on for Dart supports something similar: a package can which version(s) of the Dart SDK itself that it works with.