| #### 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 | |
| ```compile_fail,E0204 | |
| 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: | |
| ```compile_fail,E0204 | |
| #[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`). |