In Rust, how do you explicitly tie the lifetimes of two objects together, without referencing eachother?

Question

The specific case where I ran into this was in using OpenGL, writing structs for a VertexBuffer and VertexArray. Each struct is, in e

Answer 1

This is one of the primary use cases for the PhantomData type, as demonstrated there in an example.

Applied to this case, you’ll end up with something like this:

use std::marker::PhantomData;

struct VertexArray<'a> {
    id: GLuint,
    vbo_lifetime: PhantomData<&'a VertexBuffer>,
}

And instantiation will be something like this:

    fn make<'a>(&'a self) -> VertexArray<'a> {
        VertexArray {
            id: …,
            vbo_lifetime: PhantomData,
        }
    }

(This is eliding the generic type, allowing it to be inferred; you could also write PhantomData::<&'a VertexBuffer>.)