Solved rust-nightly and cargo

There is lang/rust-nightly and there is devel/cargo. I am building those via poudriere, however cargo seems to always be built with the non-nightly version of cargo.

Is there currently a way to get cargo running with rust-nightly via the ports?

I would have expected for something like DEFAULT_VERSIONS= rust=nightly, a config option or similar to exist.

EDIT: Just saw that there is RUST_PORT. Is this correct way to handle this? Why isn't it using DEFAULT_VERSIONS?
Okay. I just wondered if that was the wrong way to do it for some reason. I contacted the maintainer and offered to look into it.

Thank you for your response!