Rust Conventions

Idioms

• •Prefer iterators and combinators over explicit loops
• •Use the ? operator for error propagation — avoid manual match on Result
• •Prefer impl Trait in return position for complex return types
• •Derive Debug, Clone, PartialEq on most types; add Eq, Hash when useful
• •Prefer owned types (String, Vec<T>) in public API signatures
• •Use From/Into conversions instead of manual transformation functions
• •Prefer &str over &String in function parameters
• •Use Default trait for structs with sensible defaults

Project Structure

• •Standard Cargo layout: src/lib.rs or src/main.rs at root
• •Use workspaces (Cargo.toml with [workspace]) for multi-crate projects
• •Feature flags for optional functionality — keep the default feature set minimal
• •examples/ directory for runnable examples
• •benches/ directory for benchmarks using criterion

Testing

• •Use built-in #[cfg(test)] modules for unit tests in the same file
• •Integration tests go in tests/ directory at crate root
• •Use proptest for property-based testing of pure logic
• •Prefer assert_eq! and assert! — use assert_matches! for enum variants
• •Test error cases explicitly — ensure Result::Err paths are covered
• •Use #[should_panic] sparingly; prefer testing Result returns

Error Handling

• •Use thiserror for library error types — derive structured, typed errors
• •Use anyhow for application-level error handling
• •Never use .unwrap() or .expect() in production paths
• •.unwrap() is acceptable in tests and examples
• •Define one error enum per module or domain boundary
• •Implement Display for all error types via thiserror

Dependencies

• •Serialization: serde + serde_json
• •Async runtime: tokio (with only needed features enabled)
• •CLI: clap with derive macros
• •Logging/tracing: tracing + tracing-subscriber
• •HTTP: reqwest (client), axum (server)
• •Testing: proptest, assert_matches

Anti-patterns

• •Excessive .clone() to appease the borrow checker — restructure ownership instead
• •Stringly-typed APIs — use enums and newtypes
• •Ignoring clippy lints — run cargo clippy and address warnings
• •unsafe without a safety comment and clear justification
• •Large functions — decompose into smaller, testable units
• •Using Box<dyn Error> when a proper error enum is feasible