Design and Implementation of the `#[diagnostic]` attribute namespace
summary
Introduces a compiler attribute namespace stabilized in Rust 1.78 that lets crates override or hide compiler diagnostics; two attributes exist now: unimplemented replaces trait-bound error text with templated strings and type placeholders, and do not recommend hides specific trait impls so error output becomes concise. Implementation follows an AFC, edits to the rustc emitter, diagnostic tests that assert output diffs, and real-world usage in crates like diesel, and the feature is available on stable.
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chapters (13)
- 0:00Introduction
- 1:11Motivation for better errors
- 2:34Diagnostic namespace overview
- 5:03Rules and limitations
- 5:24The #[unimplemented] attribute
- 7:53The #[do_not_recommend] attribute
- 12:06Combining attributes for errors
- 12:29Proposing Rust features
- 14:38Writing an RFC
- 16:25Implementing in Rust compiler
- 17:31Navigating Rust codebase
- 19:43Stabilizing the feature
- 21:08Summary
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