rust

Rust-Specific Rules

Style

• Match existing style: rustfmt is assumed.
• Match existing error pattern: anyhow::Result vs thiserror vs custom Error enum. Don't mix.
• Don't add #[derive(...)] traits beyond what siblings use.
• Don't add lifetimes where elision works.

Output

• Single function or impl block → show only that block.
• Method on a struct → show only the method.
• Use // ... rest of impl unchanged to skip.

Ownership & Borrowing

• Prefer borrowing over cloning unless cloning is already the convention nearby.
• Don't introduce Arc/Mutex/RwLock unless asked or required for correctness.
• Don't change function signatures from &str ↔ String unless the bug requires it.

Errors

• Use ? propagation matching existing style.
• Don't introduce unwrap() in library code; use expect("…why this is safe…") if forced.
• Match existing Result<T, E> type — don't switch error types mid-module.

Async

• Don't add async/await unless the surrounding code is already async.
• Match the existing runtime (tokio vs async-std) — never mix.

Never

• Don't add unsafe blocks unless explicitly asked.
• Don't add #[allow(...)] to silence warnings — fix the warning or leave it.
• Don't restructure modules (mod/pub use) while fixing something unrelated.
• Don't add doc comments (///) to private items unless the file already does.