rust-patterns-book: ch04 Lifetime Branding example does not work

[rectalogic]

In the section "Lifetime Branding" of Chapter 04 (PhantomData types that carry no data):

https://microsoft.github.io/RustTraining/rust-patterns-book/ch04-phantomdata-types-that-carry-no-data.html#lifetime-branding

the branding seems to have no effect. Using the wrong handle with an arena is supposed to be a compile time error, but if I uncomment that code:

    // Can't use handle1 with a different arena — lifetimes won't match
    // let arena2 = Arena::new();
    // arena2.get(handle1); // ❌ Lifetime mismatch

I get no compile time error, but at runtime it panics because I used the wrong handle with arena2.

thread 'main' (14) panicked at src/main.rs:30:13:
index out of bounds: the len is 0 but the index is 0

Rust playground example: https://play.rust-lang.org/?version=stable&mode=debug&edition=2024&gist=4486796f55558436f8d3c482ded7bdd1

[rodrirejala]

Thanks for the issue! I'm on it, I'll open a PR soon!