coding-guidelines

| Rule | Guideline |

|------|-----------|

| No get_ prefix | fn name() not fn get_name() |

| Iterator convention | iter() / iter_mut() / into_iter() |

| Conversion naming | as_ (cheap &), to_ (expensive), into_ (ownership) |

| Static var prefix | G_CONFIG for static, no prefix for const |

| Rule | Guideline |

|------|-----------|

| Use newtypes | struct Email(String) for domain semantics |

| Prefer slice patterns | if let [first, .., last] = slice |

| Pre-allocate | Vec::with_capacity(), String::with_capacity() |

| Avoid Vec abuse | Use arrays for fixed sizes |

| Rule | Guideline |

|------|-----------|

| Prefer bytes | s.bytes() over s.chars() when ASCII |

| Use Cow | When might modify borrowed data |

| Use format! | Over string concatenation with + |

| Avoid nested iteration | contains() on string is O(n*m) |

| Rule | Guideline |

|------|-----------|

| Use ? propagation | Not try!() macro |

| expect() over unwrap() | When value guaranteed |

| Assertions for invariants | assert! at function entry |

| Rule | Guideline |

|------|-----------|

| Meaningful lifetimes | 'src, 'ctx not just 'a |

| try_borrow() for RefCell | Avoid panic |

| Shadowing for transformation | let x = x.parse()? |

| Rule | Guideline |

|------|-----------|

| Identify lock ordering | Prevent deadlocks |

| Atomics for primitives | Not Mutex for bool/usize |

| Choose memory order carefully | Relaxed/Acquire/Release/SeqCst |

| Rule | Guideline |

|------|-----------|

| Sync for CPU-bound | Async is for I/O |

| Don't hold locks across await | Use scoped guards |

| Rule | Guideline |

|------|-----------|

| Avoid unless necessary | Prefer functions/generics |

| Follow Rust syntax | Macro input should look like Rust |

| Deprecated | Better | Since |

|------------|--------|-------|

| lazy_static! | std::sync::OnceLock | 1.70 |

| once_cell::Lazy | std::sync::LazyLock | 1.80 |

| std::sync::mpsc | crossbeam::channel | - |

| std::sync::Mutex | parking_lot::Mutex | - |

| failure/error-chain | thiserror/anyhow | - |

| try!() | ? operator | 2018 |

```

Naming: snake_case (fn/var), CamelCase (type), SCREAMING_CASE (const)

Format: rustfmt (just use it)

Docs: /// for public items, //! for module docs

Lint: #![warn(clippy::all)]

```

Claude knows Rust conventions well. These are the non-obvious Rust-specific rules.