Rust and parametric packages

[raingloom]

I'm re-reading the threads about Rust packaging and I realized there
might be a solution to the build artifact reuse problem.

As I understand it, the problem is that crates can be compiled with any
number of features enabled or disabled. If this and the compiler
version are truly the only variables to consider, we could just lift
the features to the package level, right?

https://lists.gnu.org/archive/html/guix-devel/2021-02/msg00269.html