1 `derive` was applied on something which is not a struct, a union or an enum.
3 Erroneous code example:
7 #[derive(Clone)] // error!
12 As said above, the `derive` attribute is only allowed on structs, unions or
16 #[derive(Clone)] // ok!
22 You can find more information about `derive` in the [Rust Book].
24 [Rust Book]: https://doc.rust-lang.org/book/appendix-03-derivable-traits.html