error[E0119]: conflicting implementations of trait `Copy` for type `E`
  --> $DIR/duplicate-derive-copy-clone-diagnostics.rs:6:10
   |
LL | #[derive(Copy, Clone)]
   |          ---- first implementation here
LL | #[derive(Copy, Clone)]
   |          ^^^^ conflicting implementation for `E`

error[E0119]: conflicting implementations of trait `Clone` for type `E`
  --> $DIR/duplicate-derive-copy-clone-diagnostics.rs:6:16
   |
LL | #[derive(Copy, Clone)]
   |                ----- first implementation here
LL | #[derive(Copy, Clone)]
   |                ^^^^^ conflicting implementation for `E`

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0119`.