Failing to build packages with Cargo nightly

[glasserc]

Issue description

As of rust-lang/cargo#6880, cargo now creates locks in $CARGO_HOME/.cargo/.package-cache. When trying to build some cargo packages using Rust nightly (from https://github.com/mozilla/nixpkgs-mozilla/), I've gotten failures such as https://gist.github.com/glasserc/ec065e3cf7706c13742dc16fb79a931b.

Steps to reproduce

I hit this while trying to build Gecko using mozilla/nixpkgs-mozilla#175. With that patch applied, from within a checkout of Gecko, I ran: nix-shell ../nixpkgs-mozilla/release.nix -A gecko.x86_64-linux.gcc --command fish (and got the output shown above).

Technical details

 - system: `"x86_64-linux"`
 - host os: `Linux 4.19.40, NixOS, 19.03.172500.aade6ded796 (Koi)`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.2.2`
 - channels(ethan): `""`
 - channels(root): `"nixos-19.03.172500.aade6ded796"`
 - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixos`

[stale]

Thank you for your contributions.

This has been automatically marked as stale because it has had no activity for 180 days.

If this is still important to you, we ask that you leave a comment below. Your comment can be as simple as "still important to me". This lets people see that at least one person still cares about this. Someone will have to do this at most twice a year if there is no other activity.

Here are suggestions that might help resolve this more quickly:

1. Search for maintainers and people that previously touched the related code and @ mention them in a comment.
2. Ask on the NixOS Discourse.
3. Ask on the #nixos channel on irc.freenode.net.

[Atemu]

Is this still an issue?

[glasserc]

I haven't tried recently but it looks like it should be fixed by commit 3372343, per comments in #61194.