m04-zero-cost

What it does: This skill helps an AI coding helper make smart choices when writing Rust programming language code that needs to work with several different kinds of data using one shared set of rules, called a trait. It explains two ways to do this: one where the computer decides everything ahead of time, which runs faster but makes the program a bit bigger, and one where the computer decides while the program is running, which is more flexible but slightly slower. The skill also helps recognize common confusing error messages Rust gives when this setup goes wrong, and it offers simple guides and example code to pick the right approach for the situation, such as building a plugin system versus writing fast, performance-critical code. When to use it: Use it automatically when writing or fixing Rust code that involves generics, traits, or interchangeable types, especially when Rust reports errors about a type not matching or satisfying a required rule.