inheritance - What is the best way to inherit a struct in Rust 1.3?

Question

When I compile this with Rust 1.3, the compiler tells me that virtual structs have been removed from the language:

struct Foo: Bar {

}

Answer 1

Short answer, you can't do inheritance with structs.

Instead of inheritance, Rust uses composition. However, you can do inheritance within traits. Traits don't have data, but they can define functions, so you can many of the benefits of inheritance by using them:

trait Foo {
    fn foo(&self);
}

trait FooBar: Foo {
    fn foobar(&self);
}

An implementor of FooBar must implement foo (unless you provide a default implementation).

One way Rust does specialization is typically through enums, which are very powerful in Rust. One of the Rust developers wrote a good blog series about how Rust approaches these types of problems. I recommend reading through it as well as reading through the official book.