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// run-pass
#![allow(non_camel_case_types)]
#![allow(dead_code)]
#![feature(never_type)]
use std::mem::size_of;
use std::num::NonZeroU8;
struct t {a: u8, b: i8}
struct u {a: u8, b: i8, c: u8}
struct v {a: u8, b: i8, c: v2, d: u32}
struct v2 {u: char, v: u8}
struct w {a: isize, b: ()}
struct x {a: isize, b: (), c: ()}
struct y {x: isize}
enum e1 {
a(u8, u32), b(u32), c
}
enum e2 {
a(u32), b
}
#[repr(C, u8)]
enum e3 {
a([u16; 0], u8), b
}
struct ReorderedStruct {
a: u8,
b: u16,
c: u8
}
enum ReorderedEnum {
A(u8, u16, u8),
B(u8, u16, u8),
}
enum ReorderedEnum2 {
A(u8, u32, u8),
B(u16, u8, u16, u8),
// 0x100 niche variants.
_00, _01, _02, _03, _04, _05, _06, _07, _08, _09, _0A, _0B, _0C, _0D, _0E, _0F,
_10, _11, _12, _13, _14, _15, _16, _17, _18, _19, _1A, _1B, _1C, _1D, _1E, _1F,
_20, _21, _22, _23, _24, _25, _26, _27, _28, _29, _2A, _2B, _2C, _2D, _2E, _2F,
_30, _31, _32, _33, _34, _35, _36, _37, _38, _39, _3A, _3B, _3C, _3D, _3E, _3F,
_40, _41, _42, _43, _44, _45, _46, _47, _48, _49, _4A, _4B, _4C, _4D, _4E, _4F,
_50, _51, _52, _53, _54, _55, _56, _57, _58, _59, _5A, _5B, _5C, _5D, _5E, _5F,
_60, _61, _62, _63, _64, _65, _66, _67, _68, _69, _6A, _6B, _6C, _6D, _6E, _6F,
_70, _71, _72, _73, _74, _75, _76, _77, _78, _79, _7A, _7B, _7C, _7D, _7E, _7F,
_80, _81, _82, _83, _84, _85, _86, _87, _88, _89, _8A, _8B, _8C, _8D, _8E, _8F,
_90, _91, _92, _93, _94, _95, _96, _97, _98, _99, _9A, _9B, _9C, _9D, _9E, _9F,
_A0, _A1, _A2, _A3, _A4, _A5, _A6, _A7, _A8, _A9, _AA, _AB, _AC, _AD, _AE, _AF,
_B0, _B1, _B2, _B3, _B4, _B5, _B6, _B7, _B8, _B9, _BA, _BB, _BC, _BD, _BE, _BF,
_C0, _C1, _C2, _C3, _C4, _C5, _C6, _C7, _C8, _C9, _CA, _CB, _CC, _CD, _CE, _CF,
_D0, _D1, _D2, _D3, _D4, _D5, _D6, _D7, _D8, _D9, _DA, _DB, _DC, _DD, _DE, _DF,
_E0, _E1, _E2, _E3, _E4, _E5, _E6, _E7, _E8, _E9, _EA, _EB, _EC, _ED, _EE, _EF,
_F0, _F1, _F2, _F3, _F4, _F5, _F6, _F7, _F8, _F9, _FA, _FB, _FC, _FD, _FE, _FF,
}
enum EnumEmpty {}
enum EnumSingle1 {
A,
}
enum EnumSingle2 {
A = 42 as isize,
}
enum EnumSingle3 {
A,
B(!),
}
#[repr(u8)]
enum EnumSingle4 {
A,
}
#[repr(u8)]
enum EnumSingle5 {
A = 42 as u8,
}
enum EnumWithMaybeUninhabitedVariant<T> {
A(&'static ()),
B(&'static (), T),
C,
}
enum NicheFilledEnumWithAbsentVariant {
A(&'static ()),
B((), !),
C,
}
enum Option2<A, B> {
Some(A, B),
None
}
// Two layouts are considered for `CanBeNicheFilledButShouldnt`:
// Niche-filling:
// { u32 (4 bytes), NonZeroU8 + tag in niche (1 byte), padding (3 bytes) }
// Tagged:
// { tag (1 byte), NonZeroU8 (1 byte), padding (2 bytes), u32 (4 bytes) }
// Both are the same size (due to padding),
// but the tagged layout is better as the tag creates a niche with 254 invalid values,
// allowing types like `Option<Option<CanBeNicheFilledButShouldnt>>` to fit into 8 bytes.
pub enum CanBeNicheFilledButShouldnt {
A(NonZeroU8, u32),
B
}
pub enum AlwaysTaggedBecauseItHasNoNiche {
A(u8, u32),
B
}
pub fn main() {
assert_eq!(size_of::<u8>(), 1 as usize);
assert_eq!(size_of::<u32>(), 4 as usize);
assert_eq!(size_of::<char>(), 4 as usize);
assert_eq!(size_of::<i8>(), 1 as usize);
assert_eq!(size_of::<i32>(), 4 as usize);
assert_eq!(size_of::<t>(), 2 as usize);
assert_eq!(size_of::<u>(), 3 as usize);
// Alignment causes padding before the char and the u32.
assert_eq!(size_of::<v>(),
16 as usize);
assert_eq!(size_of::<isize>(), size_of::<usize>());
assert_eq!(size_of::<w>(), size_of::<isize>());
assert_eq!(size_of::<x>(), size_of::<isize>());
assert_eq!(size_of::<isize>(), size_of::<y>());
// Make sure enum types are the appropriate size, mostly
// around ensuring alignment is handled properly
assert_eq!(size_of::<e1>(), 8 as usize);
assert_eq!(size_of::<e2>(), 8 as usize);
assert_eq!(size_of::<e3>(), 4 as usize);
assert_eq!(size_of::<ReorderedStruct>(), 4);
assert_eq!(size_of::<ReorderedEnum>(), 6);
assert_eq!(size_of::<ReorderedEnum2>(), 8);
assert_eq!(size_of::<EnumEmpty>(), 0);
assert_eq!(size_of::<EnumSingle1>(), 0);
assert_eq!(size_of::<EnumSingle2>(), 0);
assert_eq!(size_of::<EnumSingle3>(), 0);
assert_eq!(size_of::<EnumSingle4>(), 1);
assert_eq!(size_of::<EnumSingle5>(), 1);
assert_eq!(size_of::<EnumWithMaybeUninhabitedVariant<!>>(),
size_of::<EnumWithMaybeUninhabitedVariant<()>>());
assert_eq!(size_of::<NicheFilledEnumWithAbsentVariant>(), size_of::<&'static ()>());
assert_eq!(size_of::<Option<Option<(bool, &())>>>(), size_of::<(bool, &())>());
assert_eq!(size_of::<Option<Option<(&(), bool)>>>(), size_of::<(bool, &())>());
assert_eq!(size_of::<Option<Option2<bool, &()>>>(), size_of::<(bool, &())>());
assert_eq!(size_of::<Option<Option2<&(), bool>>>(), size_of::<(bool, &())>());
assert_eq!(size_of::<CanBeNicheFilledButShouldnt>(), 8);
assert_eq!(size_of::<Option<CanBeNicheFilledButShouldnt>>(), 8);
assert_eq!(size_of::<Option<Option<CanBeNicheFilledButShouldnt>>>(), 8);
assert_eq!(size_of::<AlwaysTaggedBecauseItHasNoNiche>(), 8);
assert_eq!(size_of::<Option<AlwaysTaggedBecauseItHasNoNiche>>(), 8);
assert_eq!(size_of::<Option<Option<AlwaysTaggedBecauseItHasNoNiche>>>(), 8);
}
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