1 error[E0204]: the trait `Copy` cannot be implemented for this type
2 --> $DIR/union-copy.rs:12:15
4 LL | a: std::mem::ManuallyDrop<String>
5 | --------------------------------- this field does not implement `Copy`
7 LL | impl Copy for W {}
10 note: the `Copy` impl for `ManuallyDrop<String>` requires that `String: Copy`
11 --> $DIR/union-copy.rs:8:8
13 LL | a: std::mem::ManuallyDrop<String>
14 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
16 error: aborting due to 1 previous error
18 For more information about this error, try `rustc --explain E0204`.