Show full workflow from guideline => link to clippy lint

[PLeVasseur]

• pick a macro coding guideline
• begin working with clippy team to learn how to write such a clippy lint
• write the lint, feature-gate it (?) behind "safety-critical" gate
• begin work with clippy team on how to make a "safety-critical" set of lints which could be turned on which may be a bit more restrictive
• begin work with clippy team on how to generate deviation report
• develop a way to do crater runs across (sub)sets of crates which seem: a. relevant to safety-critical b. general crates
• review existing clippy lints, try to find overlap between them and MISRA Rust Addendum; if so write guidelines and then create bidirectional linkage: guidelines <=> clippy lints

[PLeVasseur]

Putting meeting notes here from discussion I had with Clippy team!

Takeaways:

recommendation to not start with trying to write Clippy lints for macros, start with something simpler

• this is varying degrees of doable, but can be quite tricky
• it's possible to pick up and check code pre-, mid(?)-, and post-expansion

having a safety-critical profile for Clippy not currently possible cleanly, but we could give some recommendations on how to configure via Config.toml and/or clippy.toml with a set of lints which correspond to the coding guidelines

• not the best user experience to tell someone to copy + paste a block of configuration into their Config.toml and/or clippy.toml
• there is a "pre-RFC" started by @Manishearth here which we could put some support and effort behind

Functionality in clippy to output outcome of lint results exists

• passed into rustc
• https://doc.rust-lang.org/rustc/command-line-arguments.html#option-error-format This flag can be used to emit compiler and Clippy diagnostics as JSON
• to make full deviation report available, likely need modifications to compiler, unclear what yet

lintcheck

• implemented in Clippy repo
• able to run on a separate TOML file for safety-critical subset

How to write a Clippy lint:

• cargo dev new_lint
• Clippy book

[PLeVasseur]

The Clippy team will have a feature freeze to work on internal quality and bug fixes.

Feature freeze starts on 2025-06-26, runs for 12 weeks.

We should try our hands at a few lints before they freeze.

From the meeting notes