1 error[E0740]: unions cannot contain fields that may need dropping
2 --> $DIR/field_checks.rs:24:5
7 = note: a type is guaranteed not to need dropping when it implements `Copy`, or when it is the special `ManuallyDrop<_>` type
8 help: when the type does not implement `Copy`, wrap it inside a `ManuallyDrop<_>` and ensure it is manually dropped
10 LL | a: std::mem::ManuallyDrop<String>,
11 | +++++++++++++++++++++++ +
13 error[E0740]: unions cannot contain fields that may need dropping
14 --> $DIR/field_checks.rs:28:5
16 LL | a: std::cell::RefCell<i32>,
17 | ^^^^^^^^^^^^^^^^^^^^^^^^^^
19 = note: a type is guaranteed not to need dropping when it implements `Copy`, or when it is the special `ManuallyDrop<_>` type
20 help: when the type does not implement `Copy`, wrap it inside a `ManuallyDrop<_>` and ensure it is manually dropped
22 LL | a: std::mem::ManuallyDrop<std::cell::RefCell<i32>>,
23 | +++++++++++++++++++++++ +
25 error[E0740]: unions cannot contain fields that may need dropping
26 --> $DIR/field_checks.rs:32:5
31 = note: a type is guaranteed not to need dropping when it implements `Copy`, or when it is the special `ManuallyDrop<_>` type
32 help: when the type does not implement `Copy`, wrap it inside a `ManuallyDrop<_>` and ensure it is manually dropped
34 LL | a: std::mem::ManuallyDrop<T>,
35 | +++++++++++++++++++++++ +
37 error[E0740]: unions cannot contain fields that may need dropping
38 --> $DIR/field_checks.rs:44:5
43 = note: a type is guaranteed not to need dropping when it implements `Copy`, or when it is the special `ManuallyDrop<_>` type
44 help: when the type does not implement `Copy`, wrap it inside a `ManuallyDrop<_>` and ensure it is manually dropped
46 LL | nest: std::mem::ManuallyDrop<U5>,
47 | +++++++++++++++++++++++ +
49 error[E0740]: unions cannot contain fields that may need dropping
50 --> $DIR/field_checks.rs:48:5
55 = note: a type is guaranteed not to need dropping when it implements `Copy`, or when it is the special `ManuallyDrop<_>` type
56 help: when the type does not implement `Copy`, wrap it inside a `ManuallyDrop<_>` and ensure it is manually dropped
58 LL | nest: std::mem::ManuallyDrop<[U5; 0]>,
59 | +++++++++++++++++++++++ +
61 error: aborting due to 5 previous errors
63 For more information about this error, try `rustc --explain E0740`.