Re: WIP patch: build-system: cargo: Make lots and lots of rust packages work

[David Craven]

> For it to work, you also have to back out the (cons "src" outputs) (in 
> ./guix/build-system/cargo.scm) and the (assoc-ref outputs "src") (in 
> guix/build/cargo-build-system.scm) starting from current master.

Can you elaborate on why you think it's a bad idea to separate the
source from the binaries into different outputs?

I see that you are trying to mimic what cargo vendor does. Cool proof
of concept and nice solution to the computing sha256 hashes on the
build side.

The question is if this is the best approach. I was thinking of trying
[0] first and see how that works for the build system use case. The
cargo package example using vendoring is intended to be a temporary
solution, and I'm not sure we have finished exploring the "design
space" yet.

[0] https://github.com/alexcrichton/cargo-local-registry