Cairo Generics and Traits Overview

Overview

Provide conceptual guidance on generics and traits, including when to use them and tradeoffs like monomorphization.

Quick Use

• •Read references/generics-traits.md before answering.
• •Use simple examples (like Option<T>) to explain placeholders for types.
• •Call out monomorphization when users ask about binary or contract size.

Response Checklist

• •Identify duplicated logic that generics can remove.
• •Explain that each concrete type produces a specialized implementation.
• •Mention traits as behavior constraints for generic types.
• •For generic impls, remind users to add required trait bounds (+Drop<T>, +Copy<T>).
• •For generic structs, remind users to add #[derive(Drop, Copy)].

Common Pitfalls

• •Missing trait bounds: Generic impls need +Drop<T> and often +Copy<T> in the impl signature.
• •Missing derives: Generic structs need #[derive(Drop, Copy)] to work with the trait bounds.
• •Syntax: Use impl Foo<T, +Drop<T>, +Copy<T>> of MyTrait<T> (note the + prefix).

Example Requests

• •"Why did my contract get bigger after adding generics?"
• •"What do generics and traits buy me in Cairo?"
• •"How do trait bounds relate to generics?"
• •"My generic implementation won't compile"

Cairo by Example

• •Generics
• •Traits
• •Bounds
• •Multiple bounds