Rust Skills

# Rust Best Practices

Comprehensive guide for writing high-quality, idiomatic, and highly optimized Rust code. Contains 179 rules across 14 categories, prioritized by impact to guide LLMs in code generation and refactoring.

## When to Apply

Reference these guidelines when:
- Writing new Rust functions, structs, or modules
- Implementing error handling or async code
- Designing public APIs for libraries
- Reviewing code for ownership/borrowing issues
- Optimizing memory usage or reducing allocations
- Tuning performance for hot paths
- Refactoring existing Rust code

## Rule Categories by Priority

| Priority | Category | Impact | Prefix | Rules |
|----------|----------|--------|--------|-------|
| 1 | Ownership & Borrowing | CRITICAL | `own-` | 12 |
| 2 | Error Handling | CRITICAL | `err-` | 12 |
| 3 | Memory Optimization | CRITICAL | `mem-` | 15 |
| 4 | API Design | HIGH | `api-` | 15 |
| 5 | Async/Await | HIGH | `async-` | 15 |
| 6 | Compiler Optimization | HIGH | `opt-` | 12 |
| 7 | Naming Conventions | MEDIUM | `name-` | 16 |
| 8 | Type Safety | MEDIUM | `type-` | 10 |
| 9 | Testing | MEDIUM | `test-` | 13 |
| 10 | Documentation | MEDIUM | `doc-` | 11 |
| 11 | Performance Patterns | MEDIUM | `perf-` | 11 |
| 12 | Project Structure | LOW | `proj-` | 11 |
| 13 | Clippy & Linting | LOW | `lint-` | 11 |
| 14 | Anti-patterns | REFERENCE | `anti-` | 15 |

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## Quick Reference

### 1. Ownership & Borrowing (CRITICAL)

- [`own-borrow-over-clone`](rules/own-borrow-over-clone.md) - Prefer `&T` borrowing over `.clone()`
- [`own-slice-over-vec`](rules/own-slice-over-vec.md) - Accept `&[T]` not `&Vec<T>`, `&str` not `&String`
- [`own-cow-conditional`](rules/own-cow-conditional.md) - Use `Cow<'a, T>` for conditional ownership
- [`own-arc-shared`](rules/own-arc-shared.md) - Use `Arc<T>` for thread-safe shared ownership
- [`own-rc-single-thread`](rules/own-rc-single-thread.md) - Use `Rc<T>` for single-threaded sharing
- [`own-refcell-interior`](rules/own-refcell-interior.md) - Use `RefCell<T>` for interior mutability (single-thread)
- [`own-mutex-interior`](rules/own-mutex-interior.md) - Use `Mutex<T>` for interior mutability (multi-thread)
- [`own-rwlock-readers`](rules/own-rwlock-readers.md) - Use `RwLock<T>` when reads dominate writes
- [`own-copy-small`](rules/own-copy-small.md) - Derive `Copy` for small, trivial types
- [`own-clone-explicit`](rules/own-clone-explicit.md) - Make `Clone` explicit, avoid implicit copies
- [`own-move-large`](rules/own-move-large.md) - Move large data instead of cloning
- [`own-lifetime-elision`](rules/own-lifetime-elision.md) - Rely on lifetime elision when possible

### 2. Error Handling (CRITICAL)

- [`err-thiserror-lib`](rules/err-thiserror-lib.md) - Use `thiserror` for library error types
- [`err-anyhow-app`](rules/err-anyhow-app.md) - Use `anyhow` for application error handling
- [`err-result-over-panic`](rules/err-result-over-panic.md) - Return `Result`, don't panic on expected errors
- [`err-context-chain`](rules/err-context-chain.md) - Add context with `.context()` or `.with_context()`
- [`err-no-unwrap-prod`](rules/err-no-unwrap-prod.md) - Never use `.unwrap()` in production code
- [`err-expect-bugs-only`](rules/err-expect-bugs-only.md) - Use `.expect()` only for programming errors
- [`err-question-mark`](rules/err-question-mark.md) - Use `?` operator for clean propagation
- [`err-from-impl`](rules/err-from-impl.md) - Use `#[from]` for automatic error conversion
- [`err-source-chain`](rul