Tracking Issue for `#[diagnostic::c_buffer_length]`

This is a tracking issue for the RFC: No RFC as per RFC-3368
The feature gate for the issue is #![feature(diagnostic_c_buffer_length)].

About tracking issues

Tracking issues are used to record the overall progress of implementation.
They are also used as hubs connecting to other relevant issues, e.g., bugs or open design questions.
A tracking issue is however not meant for large scale discussion, questions, or bug reports about a feature.
Instead, open a dedicated issue for the specific matter and add the relevant feature gate label.
Discussion comments will get marked as off-topic or deleted.
Repeated discussions on the tracking issue may lead to the tracking issue getting locked.

Steps

• Implement the RFC
• Adjust documentation (see instructions on rustc-dev-guide)
• Style updates for any new syntax (nightly-style-procedure)
  • Style team decision on new formatting
  • Formatting for new syntax has been added to the Style Guide
  • (non-blocking) Formatting has been implemented in rustfmt
• Stabilization PR (see instructions on rustc-dev-guide)

Unresolved Questions

• TBD

Implementation history

• Initial sketch issue: https://github.com/rust-lang/rust/issues/148664
• https://github.com/rust-lang/rust/pull/162565

Start with the feature gate #![feature(diagnostic_c_buffer_length)], RFC-3368, the initial sketch issue #148664, and pull request #162565. Review the tracking checklist and linked stabilization and documentation guidance; the work is complete when implementation, documentation, style decisions, and stabilization requirements are addressed.