RUSTSEC-2026-0173: proc-macro-error2 is unmaintained

| Details | |
| --- | --- |
| Package | `proc-macro-error2` |
| Version | `2.0.1` |
| Warning | unmaintained |
| URL | https://github.com/GnomedDev/proc-macro-error-2/issues/17 |
| Patched Versions | n/a |

The author of `proc-macro-error2` has [confirmed](https://github.com/GnomedDev/proc-macro-error-2/issues/17#issuecomment-4643215473) that the crate is no longer maintained and recommends that users migrate away from it.

`proc-macro-error2` was originally created as a maintained fork of [`proc-macro-error`](https://crates.io/crates/proc-macro-error) (see [RUSTSEC-2024-0370](https://rustsec.org/advisories/RUSTSEC-2024-0370)). Both the original crate and this fork are now unmaintained.

## Possible Alternative(s)

- [manyhow](https://crates.io/crates/manyhow)
- [proc-macro2-diagnostics](https://github.com/SergioBenitez/proc-macro2-diagnostics)

Start by locating the Rust workspace manifests and references to the proc-macro-error2 package, then review how it is used. Compare the listed alternatives, and consider the work complete when the unmaintained dependency has been migrated away from without breaking the workspace.

Written by the indexing model from the issue text.