#[derive(Clone, Copy)]
enum Never {}

#[repr(u32)]
enum MyEnum {
    A(Never),
    B(Never),
}

#[repr(C)]
union MyEnumRepr {
    A: MyVariantA,
    B: MyVariantB,
}

#[repr(u32)]
#[derive(Copy, Clone)]
enum MyEnumDiscriminant { A, B }

#[repr(C)]
#[derive(Clone, Copy)]
struct MyVariantA(MyEnumDiscriminant, Never);

#[repr(C)]
#[derive(Clone, Copy)]
struct MyVariantB(MyEnumDiscriminant, Never);

fn main() {
    println!("{}", size_of::<MyEnum>());
    println!("{}", size_of::<MyEnumRepr>());
}