Idiomatic Rust

Analyze existing Rust code for idiomatic patterns and generate new Rust code that follows official conventions from the Rust Reference, Standard Library, Style Guide, and API Guidelines.

Analysis Mode

When reviewing Rust code, check these dimensions in order:

1. Ownership & Borrowing — correct move/borrow/lifetime usage, minimal cloning
2. Error Handling — Result/? propagation, no unwrap in library code, typed errors
3. Naming & API Design — as_/to_/into_ conventions, getter naming, casing
4. Trait Implementations — derive standard traits, implement Display/Error/From
5. Iterator & Closure Patterns — prefer combinators over manual loops
6. Type Safety — newtypes, enums over booleans, builder pattern
7. Style & Formatting — rustfmt compliance, 100-char lines, trailing commas

Present findings as:

• Issues: Non-idiomatic patterns with file:line, explanation, and fix
• Suggestions: Improvements that would make code more Rustic
• Good: Patterns already done well (brief)

References: ownership-and-borrowing
References: error-handling
References: traits-and-types
References: naming-and-api-design
References: iterators-and-closures
References: style-and-formatting
References: concurrency

Generation Mode

When writing new Rust code:

• Derive Debug on all types; derive Clone, PartialEq, Eq, Hash, Default where appropriate
• Use thiserror for library errors, anyhow for application errors
• Accept borrowed params (&str, &[T], &Path), return owned types
• Use impl Into<String> / impl AsRef<Path> for flexible APIs
• Prefer Result<T, E> returns; reserve panic! for invariant violations
• Use iterators and combinators over manual indexing
• Apply #[must_use] on functions whose return value should not be ignored
• Add #[non_exhaustive] on public enums and structs with fields
• Write doc comments with examples using ? (not unwrap())
• Follow rustfmt defaults: 4-space indent, 100-char width, trailing commas in multi-line

Workflow

1. Read the Rust files under review (or understand the generation request)
2. Load relevant reference files for the specific patterns involved
3. For analysis: identify non-idiomatic patterns, explain why, show idiomatic alternative
4. For generation: write code following all conventions, run cargo check if available
5. Suggest cargo clippy and cargo fmt as final validation