m03-mutability

What problem does it solve?

Rust’s ownership and borrowing rules can lead to subtle mutability bugs and runtime panics if mutable access is not designed carefully. This Skill helps developers reason about when data should change, who can change it, and how to structure code to avoid borrow conflicts and runtime panics.

Core Features & Use Cases

• Mutability decisions: Guidance on when to use interior mutability, and which pattern (Cell, RefCell, Mutex, Arc<Mutex>) fits a given context.
• Borrow rules tracing: Clear mapping from borrow errors (E0499, E0502, etc.) to design decisions about ownership and access.
• Practical scenarios: From single-threaded domains to multi-threaded systems with shared state.

Quick Start

Analyze a sample Rust struct and decide an appropriate mutability strategy for shared access.