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# Error code E0206

The `Copy` trait was implemented on a type which is neither a struct, an enum, nor a union.

Erroneous code example:

    #![allow(unused)]
    fn main() {
    #[derive(Copy, Clone)]
    struct Bar;

    impl Copy for &'static mut Bar { } // error!
    }

You can only implement `Copy` for a struct, an enum, or a union. The previous example will fail because `&'static mut Bar` is not a struct, an enum, or a union.