Rust Refactoring Skill

Introduction

Use this skill when refactoring Rust code. It highlights Rust-specific code smells, suggests structural improvements, and provides a systematic workflow for safe, small refactors.

Instructions

1. •Confirm intent: Identify the refactoring goal (performance, clarity, safety, modularity) and the target scope.
2. •Scan for smells: Use the checklist in references to spot Rust-specific issues before changing code.
3. •Prefer small, reversible steps: Split large refactors into tiny changes that keep behavior intact.
4. •Structure-first refactors:
   • •Keep modules cohesive; split by domain, not by type.
   • •Prefer explicit ownership boundaries and minimal sharing.
   • •Keep public APIs small and stable; hide internal details.
   • •Ensure that refactorings do not increase the compelxity of the code.
5. •Error handling:
   • •Use domain-specific error types; avoid String errors in libraries.
   • •Prefer thiserror for library errors and anyhow for application-level contexts.
6. •Performance and correctness:
   • •Avoid needless clones; prefer borrowing and iterators.
   • •Watch for RefCell or Rc usage where ownership can be simplified.
7. •Document intent: Add small comments only for non-obvious invariants or safety assumptions.
8. •Verify: Ensure tests cover the refactor and update or add tests if behavior changes.

References

• •references/smells-checklist.md: Rust code smells and structural checklist.
• •references/do-dont-examples.md: Do/don't refactoring examples.

Examples

• •Input: "Refactor a large module with mixed responsibilities." Output: "Propose a split by domain, move shared types to a types module, and reduce public surface."
• •Input: "Improve error handling in a parsing module." Output: "Introduce a domain error enum and replace String errors with typed variants."