mirror of https://github.com/rust-lang/rust
52 lines
1.2 KiB
Rust
52 lines
1.2 KiB
Rust
//@ run-pass
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use std::mem;
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// Univariant C-like enum
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#[repr(i32)]
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enum Univariant {
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X = 17
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}
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#[repr(u16)]
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enum UnivariantWithoutDescr {
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Y
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}
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#[repr(u8)]
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enum UnivariantWithData {
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Z(u8),
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}
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pub fn main() {
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{
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assert_eq!(4, mem::size_of::<Univariant>());
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assert_eq!(17, Univariant::X as i32);
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let enums: &[Univariant] =
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&[Univariant::X, Univariant::X, Univariant::X];
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let ints: &[i32] = unsafe { mem::transmute(enums) };
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// check it has the same memory layout as i32
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assert_eq!(&[17, 17, 17], ints);
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}
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{
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assert_eq!(2, mem::size_of::<UnivariantWithoutDescr>());
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let descr = UnivariantWithoutDescr::Y as u16;
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let enums: &[UnivariantWithoutDescr] =
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&[UnivariantWithoutDescr::Y, UnivariantWithoutDescr::Y, UnivariantWithoutDescr::Y];
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let ints: &[u16] = unsafe { mem::transmute(enums) };
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// check it has the same memory layout as u16
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assert_eq!(&[descr, descr, descr], ints);
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}
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{
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assert_eq!(2, mem::size_of::<UnivariantWithData>());
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match UnivariantWithData::Z(4) {
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UnivariantWithData::Z(x) => assert_eq!(x, 4),
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}
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}
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}
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