The equivalent of a function returning Result<T, E> in Rust would be returning something like unique_ptr<ResultBaseClass<T,E>> because the two subclasses have d

The equivalent of a function returning Result<T, E> in Rust would be returning something like unique_ptr<ResultBaseClass<T,E>> because the two subclasses have different sizes and thus can't be returned directly (or else one will be object slicing). The struct version stores everything inline from the start (it has a single static size) and so can be returned without needing a pointer.