Implement core::error::Error for no_std environment

[metent]

core::error::Error has been stable for a while. Can we merge this?

[finnbear]

Hello, thank you! It looks like core::error::Error was stabilized on 5 September, 2024 which is less than one year ago (by a few days). It is also incompatible with the version of Rust nightly that we use for our internal projects (20 April, 2024). As a result, even though the way you've written it would only affect no_std users, it will be some time before we merge this.

Also, before we merge this, we should change it to unconditionally say core::error::Error which is an alias of std::error::Error.

You can create a wrapper error type as a workaround.

[metent]

Hi! Thanks for the explanation. I totally understand the nightly Rust version constraint.

Since this change only requires swapping std::error::Error -> core::error::Error (a 1-line fix), you could implement this yourself whenever it fits your schedule. I’ll be happy to open an issue for this if needed.

No need to wait on me—I’ll step back and let you handle it however works best!