> I wanted to express the fact that everything that gets allocated (call stack, frames, classes, and objects) is alive and valid until the "root" VM is, thus I used 'a more or less everywhere.

That's not being expressed in the type system. The lifetime 'a is unbounded (meaning you can make it anything you want, including 'static) so anything that shares 'a can outlive the vm without rust complaining. it would be no different then if you removed 'a completely. If you wanted to ensure anything couldn't outlive the vm you could tie the lifetime to a reference to the vm, but then the vm can't hold those values (it would be a self-referential lifetime).