Weird build failure from cargo in microkelvin 0.4.0

[Nemo157]

Crate name: microkelvin
Build failure link: https://docs.rs/crate/microkelvin/0.4.0/builds/309422

Additional details:
Not my crate, but I noticed this randomly. It is cargo that is emitting the error here, it seems to think it needs to re-extract const-arrayvec even though it's already extracted.

[jyn514]

This is a cargo bug, right? Shouldn't it be reported upstream? I don't think it should ever touch registry/src once it's been populated the first time.

[Nemo157]

I think so, I'm gonna take a closer look later and probably open an upstream issue, but just in case it's something we're doing wrong.

[Nemo157]

This was just fixed on the cargo side, once there's a new version of cargo in a nightly we could retry microkelvin and see if it builds now.

[jyn514]

This is waiting on rust-lang/rust#78972.

[jyn514]

I rebuilt it; it gave a compile error but nothing from cargo.

https://docs.rs/crate/microkelvin/0.4.0/builds/317833