1 // run-pass
2
3 use std::mem;
4
5 // Univariant C-like enum
6 #[repr(i32)]
7 enum Univariant {
8 X = 17
9 }
10
11 #[repr(u16)]
12 enum UnivariantWithoutDescr {
13 Y
14 }
15
16 #[repr(u8)]
17 enum UnivariantWithData {
18 Z(u8),
19 }
20
main()21 pub fn main() {
22 {
23 assert_eq!(4, mem::size_of::<Univariant>());
24 assert_eq!(17, Univariant::X as i32);
25
26 let enums: &[Univariant] =
27 &[Univariant::X, Univariant::X, Univariant::X];
28 let ints: &[i32] = unsafe { mem::transmute(enums) };
29 // check it has the same memory layout as i32
30 assert_eq!(&[17, 17, 17], ints);
31 }
32
33 {
34 assert_eq!(2, mem::size_of::<UnivariantWithoutDescr>());
35 let descr = UnivariantWithoutDescr::Y as u16;
36
37 let enums: &[UnivariantWithoutDescr] =
38 &[UnivariantWithoutDescr::Y, UnivariantWithoutDescr::Y, UnivariantWithoutDescr::Y];
39 let ints: &[u16] = unsafe { mem::transmute(enums) };
40 // check it has the same memory layout as u16
41 assert_eq!(&[descr, descr, descr], ints);
42 }
43
44 {
45 assert_eq!(2, mem::size_of::<UnivariantWithData>());
46
47 match UnivariantWithData::Z(4) {
48 UnivariantWithData::Z(x) => assert_eq!(x, 4),
49 }
50 }
51 }
52