“Inheritance” in Rust: Supertraits

#![allow(unused)]
fn main() {
pub trait SuperTrait {}

pub trait Trait: SuperTrait {}
}

  • In Rust, traits can depend on other traits. We’re already familiar with Traits being able to have Supertraits.

  • This looks superficially similar to inheritance.

  • This is a mechanism like inheritance, but separates the data from the behavior.

  • Keeps behavior in a state where it’s easy to reason about.

  • Makes what we aim to achieve with “multiple inheritance” easier too:

    We only care about what behavior a type is capable of at the point where we clarify we want that behavior (when bounding a generic by traits).

    By specifying multiple traits on a generic, we know that the type has the methods of all those traits.

  • Does not involve inheritance of fields. A trait doesn’t expose fields, only methods and associated types / constants.