Concept: Language-Design

Traits Versus Statically Resolved Type Parameters

Rust’s trait system is often compared to Haskell’s type classes, suggesting that Rust has successfully brought type class polymorphism to systems programming. While Rust’s traits are indeed inspired by type classes and provide powerful abstractions, examining the actual mechanics reveals important differences. Rust’s traits, as a multi-paradigm systems language feature, make deliberate design tradeoffs that differ in important ways from Haskell’s type classes. It’s worth taking a sidebar to also review how it compares to F#’s approach to polymorphism.