E0205 - Error codes index
Description: Book listing all Rust error codes

# Error code E0205

#### Note: this error code is no longer emitted by the compiler.

An attempt to implement the `Copy` trait for an enum failed because one of the variants does not implement `Copy`. To fix this, you must implement `Copy` for the mentioned variant. Note that this may not be possible, as in the example of

    #![allow(unused)]
    fn main() {
    enum Foo {
        Bar(Vec<u32>),
        Baz,
    }

    impl Copy for Foo { }
    }

This fails because `Vec<T>` does not implement `Copy` for any `T`.

Here's another example that will fail:

    #![allow(unused)]
    fn main() {
    #[derive(Copy)]
    enum Foo<'a> {
        Bar(&'a mut bool),
        Baz,
    }
    }

This fails because `&mut T` is not `Copy`, even when `T` is `Copy` (this differs from the behavior for `&T`, which is always `Copy`).