When is a class's destructor called?

[ponce]

> Ok, I understand that, but since I don't have a garbage 
> collector, what must I implement to call the destructor when it 
> goes out of scope?
>
> Another way of asking the question is: How does the garbage 
> collector know when something has gone out of scope and is 
> therefore safe to collect?  And where is that implemented in 
> the runtime?

If you want deterministic destruction, you have plenty of choices:
- scoped!
- using structs instead
- scope(exit)
- RefCounted!
- Unique!
- ...

Yet using classes for ressources is not composable. It's either:
- using classes for the convenience and deal with resource 
release manually
- using structs

It's an open quesiton for me which choice is best.