# Advanced Hands-on Rust: pg 56 incorrect derive resource

**URL:** <https://forum.devtalk.com/t/advanced-hands-on-rust-pg-56-incorrect-derive-resource/245373>\
**Category:** PragProg Customers\
**Tags:** book-advanced-hands-on-rust, errata\
**Created:** [19 May 2026 04:00 UTC](https://forum.devtalk.com/t/advanced-hands-on-rust-pg-56-incorrect-derive-resource/245373 "2026-05-19T04:00:17Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![RockLikeAmadeus](https://forum.devtalk.com/user_avatar/forum.devtalk.com/rocklikeamadeus/32/8079_2.png) [@RockLikeAmadeus](https://forum.devtalk.com/u/RockLikeAmadeus)\
**Post date:** [19 May 2026 04:00 UTC](https://forum.devtalk.com/t/advanced-hands-on-rust-pg-56-incorrect-derive-resource/245373/1 "2026-05-19T04:00:17Z")

</div>

On page 56, it says you’re specifying the RNG back end as follows:

```rust
#[derive(Resource)]
pub struct RandomNumberGenerator {
  rng: StdRng,
}

```

This is wrong, we don’t derive resource for this struct until page 64.