v0.1.0 to v0.1.0

---

name: coding-rust

version: 0.1.0

description: Rust naming conventions, ownership patterns, error handling, and quality overrides for ECHO Protocol.

---

# Rust Coding Standards

<!-- Load this when protocol.config.yaml has language: "rust" -->

## Naming Conventions

| Element | Convention | Example |

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

| Structs | PascalCase | `UserProfile`, `GameState` |

| Enums | PascalCase | `PlayerAction`, `TileType` |

| Enum variants | PascalCase | `TileType::Grassland` |

| Functions | snake_case | `calculate_distance`, `spawn_unit` |

| Variables | snake_case | `player_count`, `is_valid` |

| Constants | UPPER_SNAKE_CASE | `MAX_PLAYERS`, `TILE_SIZE` |

| Statics | UPPER_SNAKE_CASE | `GLOBAL_CONFIG` |

| Modules | snake_case | `player_manager`, `world_gen` |

| Files | snake_case.rs | `player_manager.rs`, `world_gen.rs` |

| Traits | PascalCase (noun/adjective) | `Serializable`, `Renderable` |

| Type aliases | PascalCase | `PlayerId`, `TileGrid` |

| Lifetimes | short lowercase | `'a`, `'ctx`, `'de` |

## Patterns

### Error Handling

- Use `Result<T, E>` for all fallible operations

- Never use `unwrap()` or `expect()` in non-test code — use `?` operator, `match`, or explicit error types

- `.expect("reason")` is acceptable only in tests, examples, and `main.rs` where panicking is the intended behavior

- Define project-specific error types using `thiserror`

- Use `anyhow` for application-level error propagation

### Ownership

- Prefer borrowing (`&T`) over cloning

- Use `Arc<Mutex<T>>` for shared mutable state

- Use `Rc<T>` for single-threaded shared ownership

- Document lifetime elision decisions in complex cases

### Imports

- Group: std → external crates → local modules

- One blank line between groups

- Prefer explicit imports over glob (`use module::*`)

- Re-export public types at module boundaries

## File Structure

```text

src/

├── main.rs # Entry point only

├── lib.rs # Public API surface

├── config.rs # Configuration types

├── error.rs # Error types

├── [module]/

│ ├── mod.rs # Module re-exports

│ ├── types.rs # Data structures

│ ├── logic.rs # Business logic

│ └── tests.rs # Unit tests (or inline)

```

## Anti-Patterns to Flag

- [ ] `unwrap()` in non-test code

- [ ] `clone()` without justification

- [ ] `unsafe` blocks without safety comments

- [ ] `Box<dyn Error>` instead of typed errors

- [ ] Dead code (unused functions/imports)

- [ ] `todo!()` or `unimplemented!()` without FID reference