Perhaps I am being cynical, but this doesn't really provide a better explanation about Rust's ADT enums than the official Rust book, albeit with the note about

Perhaps I am being cynical, but this doesn't really provide a better explanation about Rust's ADT enums than the official Rust book, albeit with the note about `#[repr(...)]`. Seems a bit low effort, I would have liked to have seen some examples that are more practical and less foobar-ish.