m03-mutability

Interior mutability patterns like Cell, RefCell, and Mutex resolve borrow-check conflicts by allowing safe mutation through immutable references. This Skill analyzes conflicts and proposes appropriate wrappers for single-threaded and multi-threaded contexts.

Interior mutability allows mutation through immutable references using Cell or RefCell. Use it when borrow-check rules prevent safe structural mutation, specifically for managing single-threaded state without runtime borrow panics.

Prevent RefCell runtime borrow panics by applying guided refactoring patterns that ensure borrow scopes do not overlap. This Skill detects borrow conflicts and proposes safe mutability designs to avoid runtime panics.

Choose Mutex for exclusive write access or RwLock for concurrent multiple readers in multi-threaded Rust contexts. This Skill outlines when to use these wrappers versus immutable designs based on safe access requirements.

Avoid interior mutability when your project architecture can be restructured to pass ownership safely without wrappers. This Skill outlines when to use immutable designs versus interior mutability to achieve clearer ownership and safer APIs.