wrong nightly rust version

[lolbinarycat]

$ nix shell github:oxalica/rust-overlay#rust-nightly_2024-06-01
$ cargo version
cargo 1.80.0-nightly (431db31d0 2024-05-28)

this seems quite bad?

[lolbinarycat]

locked version:

$ nix shell github:oxalica/rust-overlay/ab69b67fac9a96709fbef0b899db308ca714a120#rust-nightly_2024-06-01
$ cargo version
cargo 1.80.0-nightly (431db31d0 2024-05-28)

[oxalica]

The URL is correct and it's producing the same result as rustup's nightly toolchain. rustc --version also shows the expected result.

I guess it's because nightly is shipped based on the rust-lang/rust repo itself, which contains a snapshot of all tools (including cargo). And not every tool is updated every day, their submodule is updated in a batch manner.
The last cargo update PR seems to be just after the nightly release time rust-lang/rust#125835, and the second last one is merged on 2024-05-28 rust-lang/rust#125682 which is what you see.