3 // This file tests repr(no_niche), which causes an struct/enum to hide
4 // any niche space that may exist in its internal state from the
5 // context it appears in.
7 // Here are the axes this test is seeking to cover:
10 // visible: (); cloaked: (no_niche); transparent: (transparent); shadowy: (transparent, no_niche)
14 // niche-type via type-parameter vs inline declaration
16 #![feature(decl_macro)]
19 use std::mem::size_of;
20 use std::num::{NonZeroU8, NonZeroU16};
23 use std::num::NonZeroU16 as N16;
25 #[derive(Debug)] pub struct Visible(N16);
28 #[derive(Debug)] pub struct Cloaked(N16);
31 #[derive(Debug)] pub struct Transparent(N16);
33 #[repr(transparent, no_niche)]
34 #[derive(Debug)] pub struct Shadowy(N16);
38 #[derive(Debug)] pub struct Visible<T>(T);
41 #[derive(Debug)] pub struct Cloaked<T>(T);
44 #[derive(Debug)] pub struct Transparent<T>(T);
46 #[repr(transparent, no_niche)]
47 #[derive(Debug)] pub struct Shadowy<T>(T);
51 use crate::two_fifty_six_variant_enum;
52 use std::num::{NonZeroU8 as N8, NonZeroU16 as N16};
54 #[derive(Debug)] pub enum Visible1 { _A(N16), }
57 #[derive(Debug)] pub enum Cloaked1 { _A(N16), }
59 // (N.B.: transparent enums must be univariant)
61 #[derive(Debug)] pub enum Transparent { _A(N16), }
63 #[repr(transparent, no_niche)]
64 #[derive(Debug)] pub enum Shadowy { _A(N16), }
66 // including multivariant enums for completeness. Payload and
67 // number of variants (i.e. discriminant size) have been chosen so
68 // that layout including discriminant is 4 bytes, with no space in
69 // padding to hide another discrimnant from the surrounding
72 // (Note that multivariant enums cannot usefully expose a niche in
73 // general; this test is relying on that.)
74 two_fifty_six_variant_enum!(Visible2, N8);
76 two_fifty_six_variant_enum!(#[repr(no_niche)] Cloaked2, N8);
80 use super::two_fifty_six_variant_enum;
82 #[derive(Debug)] pub enum Visible1<T> { _A(T), }
85 #[derive(Debug)] pub enum Cloaked1<T> { _A(T), }
87 // (N.B.: transparent enums must be univariant)
89 #[derive(Debug)] pub enum Transparent<T> { _A(T), }
91 #[repr(transparent, no_niche)]
92 #[derive(Debug)] pub enum Shadowy<T> { _A(T), }
94 // including multivariant enums for completeness. Same notes apply
95 // here as above (assuming `T` is instantiated with `NonZeroU8`).
96 two_fifty_six_variant_enum!(Visible2<T>);
98 two_fifty_six_variant_enum!(#[repr(no_niche)] Cloaked2<T>);
103 assert_eq!(size_of::<struct_inline::Visible>(), 2);
104 assert_eq!(size_of::<struct_inline::Cloaked>(), 2);
105 assert_eq!(size_of::<struct_inline::Transparent>(), 2);
106 assert_eq!(size_of::<struct_inline::Shadowy>(), 2);
108 assert_eq!(size_of::<struct_param::Visible<NonZeroU16>>(), 2);
109 assert_eq!(size_of::<struct_param::Cloaked<NonZeroU16>>(), 2);
110 assert_eq!(size_of::<struct_param::Transparent<NonZeroU16>>(), 2);
111 assert_eq!(size_of::<struct_param::Shadowy<NonZeroU16>>(), 2);
113 assert_eq!(size_of::<enum_inline::Visible1>(), 2);
114 assert_eq!(size_of::<enum_inline::Cloaked1>(), 2);
115 assert_eq!(size_of::<enum_inline::Transparent>(), 2); // transparent enums are univariant
116 assert_eq!(size_of::<enum_inline::Shadowy>(), 2);
117 assert_eq!(size_of::<enum_inline::Visible2>(), 4);
118 assert_eq!(size_of::<enum_inline::Cloaked2>(), 4);
120 assert_eq!(size_of::<enum_param::Visible1<NonZeroU16>>(), 2);
121 assert_eq!(size_of::<enum_param::Cloaked1<NonZeroU16>>(), 2);
122 assert_eq!(size_of::<enum_param::Transparent<NonZeroU16>>(), 2);
123 assert_eq!(size_of::<enum_param::Shadowy<NonZeroU16>>(), 2);
124 assert_eq!(size_of::<enum_param::Visible2<NonZeroU8>>(), 4);
125 assert_eq!(size_of::<enum_param::Cloaked2<NonZeroU8>>(), 4);
127 // now the actual tests of no_niche: how do inputs above compose
128 // with `Option` type constructor. The cases with a `_+2` are the
129 // ones where no_niche fires.
130 assert_eq!(size_of::<Option<struct_inline::Visible>>(), 2);
131 assert_eq!(size_of::<Option<struct_inline::Cloaked>>(), 2+2);
132 assert_eq!(size_of::<Option<struct_inline::Transparent>>(), 2);
133 assert_eq!(size_of::<Option<struct_inline::Shadowy>>(), 2+2);
135 assert_eq!(size_of::<Option<struct_param::Visible<NonZeroU16>>>(), 2);
136 assert_eq!(size_of::<Option<struct_param::Cloaked<NonZeroU16>>>(), 2+2);
137 assert_eq!(size_of::<Option<struct_param::Transparent<NonZeroU16>>>(), 2);
138 assert_eq!(size_of::<Option<struct_param::Shadowy<NonZeroU16>>>(), 2+2);
140 assert_eq!(size_of::<Option<enum_inline::Visible1>>(), 2);
141 assert_eq!(size_of::<Option<enum_inline::Cloaked1>>(), 2+2);
142 assert_eq!(size_of::<Option<enum_inline::Transparent>>(), 2);
143 assert_eq!(size_of::<Option<enum_inline::Shadowy>>(), 2+2);
144 // cannot use niche of multivariant payload
145 assert_eq!(size_of::<Option<enum_inline::Visible2>>(), 4+2);
146 assert_eq!(size_of::<Option<enum_inline::Cloaked2>>(), 4+2);
148 assert_eq!(size_of::<Option<enum_param::Visible1<NonZeroU16>>>(), 2);
149 assert_eq!(size_of::<Option<enum_param::Cloaked1<NonZeroU16>>>(), 2+2);
150 assert_eq!(size_of::<Option<enum_param::Transparent<NonZeroU16>>>(), 2);
151 assert_eq!(size_of::<Option<enum_param::Shadowy<NonZeroU16>>>(), 2+2);
152 // cannot use niche of multivariant payload
153 assert_eq!(size_of::<Option<enum_param::Visible2<NonZeroU8>>>(), 4+2);
154 assert_eq!(size_of::<Option<enum_param::Cloaked2<NonZeroU8>>>(), 4+2);
157 macro two_fifty_six_variant_enum {
158 ($(#[$attr:meta])* $name:ident<$param:ident>) => {
159 #[derive(Debug)] $(#[$attr])*
160 pub enum $name<$param> {
161 _V00($param, u16), _V01(u16, $param), _V02($param, u16), _V03(u16, $param),
162 _V04($param, u16), _V05(u16, $param), _V06($param, u16), _V07(u16, $param),
163 _V08($param, u16), _V09(u16, $param), _V0a($param, u16), _V0b(u16, $param),
164 _V0c($param, u16), _V0d(u16, $param), _V0e($param, u16), _V0f(u16, $param),
166 _V10($param, u16), _V11(u16, $param), _V12($param, u16), _V13(u16, $param),
167 _V14($param, u16), _V15(u16, $param), _V16($param, u16), _V17(u16, $param),
168 _V18($param, u16), _V19(u16, $param), _V1a($param, u16), _V1b(u16, $param),
169 _V1c($param, u16), _V1d(u16, $param), _V1e($param, u16), _V1f(u16, $param),
171 _V20($param, u16), _V21(u16, $param), _V22($param, u16), _V23(u16, $param),
172 _V24($param, u16), _V25(u16, $param), _V26($param, u16), _V27(u16, $param),
173 _V28($param, u16), _V29(u16, $param), _V2a($param, u16), _V2b(u16, $param),
174 _V2c($param, u16), _V2d(u16, $param), _V2e($param, u16), _V2f(u16, $param),
176 _V30($param, u16), _V31(u16, $param), _V32($param, u16), _V33(u16, $param),
177 _V34($param, u16), _V35(u16, $param), _V36($param, u16), _V37(u16, $param),
178 _V38($param, u16), _V39(u16, $param), _V3a($param, u16), _V3b(u16, $param),
179 _V3c($param, u16), _V3d(u16, $param), _V3e($param, u16), _V3f(u16, $param),
181 _V40($param, u16), _V41(u16, $param), _V42($param, u16), _V43(u16, $param),
182 _V44($param, u16), _V45(u16, $param), _V46($param, u16), _V47(u16, $param),
183 _V48($param, u16), _V49(u16, $param), _V4a($param, u16), _V4b(u16, $param),
184 _V4c($param, u16), _V4d(u16, $param), _V4e($param, u16), _V4f(u16, $param),
186 _V50($param, u16), _V51(u16, $param), _V52($param, u16), _V53(u16, $param),
187 _V54($param, u16), _V55(u16, $param), _V56($param, u16), _V57(u16, $param),
188 _V58($param, u16), _V59(u16, $param), _V5a($param, u16), _V5b(u16, $param),
189 _V5c($param, u16), _V5d(u16, $param), _V5e($param, u16), _V5f(u16, $param),
191 _V60($param, u16), _V61(u16, $param), _V62($param, u16), _V63(u16, $param),
192 _V64($param, u16), _V65(u16, $param), _V66($param, u16), _V67(u16, $param),
193 _V68($param, u16), _V69(u16, $param), _V6a($param, u16), _V6b(u16, $param),
194 _V6c($param, u16), _V6d(u16, $param), _V6e($param, u16), _V6f(u16, $param),
196 _V70($param, u16), _V71(u16, $param), _V72($param, u16), _V73(u16, $param),
197 _V74($param, u16), _V75(u16, $param), _V76($param, u16), _V77(u16, $param),
198 _V78($param, u16), _V79(u16, $param), _V7a($param, u16), _V7b(u16, $param),
199 _V7c($param, u16), _V7d(u16, $param), _V7e($param, u16), _V7f(u16, $param),
201 _V80($param, u16), _V81(u16, $param), _V82($param, u16), _V83(u16, $param),
202 _V84($param, u16), _V85(u16, $param), _V86($param, u16), _V87(u16, $param),
203 _V88($param, u16), _V89(u16, $param), _V8a($param, u16), _V8b(u16, $param),
204 _V8c($param, u16), _V8d(u16, $param), _V8e($param, u16), _V8f(u16, $param),
206 _V90($param, u16), _V91(u16, $param), _V92($param, u16), _V93(u16, $param),
207 _V94($param, u16), _V95(u16, $param), _V96($param, u16), _V97(u16, $param),
208 _V98($param, u16), _V99(u16, $param), _V9a($param, u16), _V9b(u16, $param),
209 _V9c($param, u16), _V9d(u16, $param), _V9e($param, u16), _V9f(u16, $param),
211 _Va0($param, u16), _Va1(u16, $param), _Va2($param, u16), _Va3(u16, $param),
212 _Va4($param, u16), _Va5(u16, $param), _Va6($param, u16), _Va7(u16, $param),
213 _Va8($param, u16), _Va9(u16, $param), _Vaa($param, u16), _Vab(u16, $param),
214 _Vac($param, u16), _Vad(u16, $param), _Vae($param, u16), _Vaf(u16, $param),
216 _Vb0($param, u16), _Vb1(u16, $param), _Vb2($param, u16), _Vb3(u16, $param),
217 _Vb4($param, u16), _Vb5(u16, $param), _Vb6($param, u16), _Vb7(u16, $param),
218 _Vb8($param, u16), _Vb9(u16, $param), _Vba($param, u16), _Vbb(u16, $param),
219 _Vbc($param, u16), _Vbd(u16, $param), _Vbe($param, u16), _Vbf(u16, $param),
221 _Vc0($param, u16), _Vc1(u16, $param), _Vc2($param, u16), _Vc3(u16, $param),
222 _Vc4($param, u16), _Vc5(u16, $param), _Vc6($param, u16), _Vc7(u16, $param),
223 _Vc8($param, u16), _Vc9(u16, $param), _Vca($param, u16), _Vcb(u16, $param),
224 _Vcc($param, u16), _Vcd(u16, $param), _Vce($param, u16), _Vcf(u16, $param),
226 _Vd0($param, u16), _Vd1(u16, $param), _Vd2($param, u16), _Vd3(u16, $param),
227 _Vd4($param, u16), _Vd5(u16, $param), _Vd6($param, u16), _Vd7(u16, $param),
228 _Vd8($param, u16), _Vd9(u16, $param), _Vda($param, u16), _Vdb(u16, $param),
229 _Vdc($param, u16), _Vdd(u16, $param), _Vde($param, u16), _Vdf(u16, $param),
231 _Ve0($param, u16), _Ve1(u16, $param), _Ve2($param, u16), _Ve3(u16, $param),
232 _Ve4($param, u16), _Ve5(u16, $param), _Ve6($param, u16), _Ve7(u16, $param),
233 _Ve8($param, u16), _Ve9(u16, $param), _Vea($param, u16), _Veb(u16, $param),
234 _Vec($param, u16), _Ved(u16, $param), _Vee($param, u16), _Vef(u16, $param),
236 _Vf0($param, u16), _Vf1(u16, $param), _Vf2($param, u16), _Vf3(u16, $param),
237 _Vf4($param, u16), _Vf5(u16, $param), _Vf6($param, u16), _Vf7(u16, $param),
238 _Vf8($param, u16), _Vf9(u16, $param), _Vfa($param, u16), _Vfb(u16, $param),
239 _Vfc($param, u16), _Vfd(u16, $param), _Vfe($param, u16), _Vff(u16, $param),
243 ($(#[$attr:meta])* $name:ident, $param:ty) => {
244 #[derive(Debug)] $(#[$attr])*
246 _V00($param, u16), _V01(u16, $param), _V02($param, u16), _V03(u16, $param),
247 _V04($param, u16), _V05(u16, $param), _V06($param, u16), _V07(u16, $param),
248 _V08($param, u16), _V09(u16, $param), _V0a($param, u16), _V0b(u16, $param),
249 _V0c($param, u16), _V0d(u16, $param), _V0e($param, u16), _V0f(u16, $param),
251 _V10($param, u16), _V11(u16, $param), _V12($param, u16), _V13(u16, $param),
252 _V14($param, u16), _V15(u16, $param), _V16($param, u16), _V17(u16, $param),
253 _V18($param, u16), _V19(u16, $param), _V1a($param, u16), _V1b(u16, $param),
254 _V1c($param, u16), _V1d(u16, $param), _V1e($param, u16), _V1f(u16, $param),
256 _V20($param, u16), _V21(u16, $param), _V22($param, u16), _V23(u16, $param),
257 _V24($param, u16), _V25(u16, $param), _V26($param, u16), _V27(u16, $param),
258 _V28($param, u16), _V29(u16, $param), _V2a($param, u16), _V2b(u16, $param),
259 _V2c($param, u16), _V2d(u16, $param), _V2e($param, u16), _V2f(u16, $param),
261 _V30($param, u16), _V31(u16, $param), _V32($param, u16), _V33(u16, $param),
262 _V34($param, u16), _V35(u16, $param), _V36($param, u16), _V37(u16, $param),
263 _V38($param, u16), _V39(u16, $param), _V3a($param, u16), _V3b(u16, $param),
264 _V3c($param, u16), _V3d(u16, $param), _V3e($param, u16), _V3f(u16, $param),
266 _V40($param, u16), _V41(u16, $param), _V42($param, u16), _V43(u16, $param),
267 _V44($param, u16), _V45(u16, $param), _V46($param, u16), _V47(u16, $param),
268 _V48($param, u16), _V49(u16, $param), _V4a($param, u16), _V4b(u16, $param),
269 _V4c($param, u16), _V4d(u16, $param), _V4e($param, u16), _V4f(u16, $param),
271 _V50($param, u16), _V51(u16, $param), _V52($param, u16), _V53(u16, $param),
272 _V54($param, u16), _V55(u16, $param), _V56($param, u16), _V57(u16, $param),
273 _V58($param, u16), _V59(u16, $param), _V5a($param, u16), _V5b(u16, $param),
274 _V5c($param, u16), _V5d(u16, $param), _V5e($param, u16), _V5f(u16, $param),
276 _V60($param, u16), _V61(u16, $param), _V62($param, u16), _V63(u16, $param),
277 _V64($param, u16), _V65(u16, $param), _V66($param, u16), _V67(u16, $param),
278 _V68($param, u16), _V69(u16, $param), _V6a($param, u16), _V6b(u16, $param),
279 _V6c($param, u16), _V6d(u16, $param), _V6e($param, u16), _V6f(u16, $param),
281 _V70($param, u16), _V71(u16, $param), _V72($param, u16), _V73(u16, $param),
282 _V74($param, u16), _V75(u16, $param), _V76($param, u16), _V77(u16, $param),
283 _V78($param, u16), _V79(u16, $param), _V7a($param, u16), _V7b(u16, $param),
284 _V7c($param, u16), _V7d(u16, $param), _V7e($param, u16), _V7f(u16, $param),
286 _V80($param, u16), _V81(u16, $param), _V82($param, u16), _V83(u16, $param),
287 _V84($param, u16), _V85(u16, $param), _V86($param, u16), _V87(u16, $param),
288 _V88($param, u16), _V89(u16, $param), _V8a($param, u16), _V8b(u16, $param),
289 _V8c($param, u16), _V8d(u16, $param), _V8e($param, u16), _V8f(u16, $param),
291 _V90($param, u16), _V91(u16, $param), _V92($param, u16), _V93(u16, $param),
292 _V94($param, u16), _V95(u16, $param), _V96($param, u16), _V97(u16, $param),
293 _V98($param, u16), _V99(u16, $param), _V9a($param, u16), _V9b(u16, $param),
294 _V9c($param, u16), _V9d(u16, $param), _V9e($param, u16), _V9f(u16, $param),
296 _Va0($param, u16), _Va1(u16, $param), _Va2($param, u16), _Va3(u16, $param),
297 _Va4($param, u16), _Va5(u16, $param), _Va6($param, u16), _Va7(u16, $param),
298 _Va8($param, u16), _Va9(u16, $param), _Vaa($param, u16), _Vab(u16, $param),
299 _Vac($param, u16), _Vad(u16, $param), _Vae($param, u16), _Vaf(u16, $param),
301 _Vb0($param, u16), _Vb1(u16, $param), _Vb2($param, u16), _Vb3(u16, $param),
302 _Vb4($param, u16), _Vb5(u16, $param), _Vb6($param, u16), _Vb7(u16, $param),
303 _Vb8($param, u16), _Vb9(u16, $param), _Vba($param, u16), _Vbb(u16, $param),
304 _Vbc($param, u16), _Vbd(u16, $param), _Vbe($param, u16), _Vbf(u16, $param),
306 _Vc0($param, u16), _Vc1(u16, $param), _Vc2($param, u16), _Vc3(u16, $param),
307 _Vc4($param, u16), _Vc5(u16, $param), _Vc6($param, u16), _Vc7(u16, $param),
308 _Vc8($param, u16), _Vc9(u16, $param), _Vca($param, u16), _Vcb(u16, $param),
309 _Vcc($param, u16), _Vcd(u16, $param), _Vce($param, u16), _Vcf(u16, $param),
311 _Vd0($param, u16), _Vd1(u16, $param), _Vd2($param, u16), _Vd3(u16, $param),
312 _Vd4($param, u16), _Vd5(u16, $param), _Vd6($param, u16), _Vd7(u16, $param),
313 _Vd8($param, u16), _Vd9(u16, $param), _Vda($param, u16), _Vdb(u16, $param),
314 _Vdc($param, u16), _Vdd(u16, $param), _Vde($param, u16), _Vdf(u16, $param),
316 _Ve0($param, u16), _Ve1(u16, $param), _Ve2($param, u16), _Ve3(u16, $param),
317 _Ve4($param, u16), _Ve5(u16, $param), _Ve6($param, u16), _Ve7(u16, $param),
318 _Ve8($param, u16), _Ve9(u16, $param), _Vea($param, u16), _Veb(u16, $param),
319 _Vec($param, u16), _Ved(u16, $param), _Vee($param, u16), _Vef(u16, $param),
321 _Vf0($param, u16), _Vf1(u16, $param), _Vf2($param, u16), _Vf3(u16, $param),
322 _Vf4($param, u16), _Vf5(u16, $param), _Vf6($param, u16), _Vf7(u16, $param),
323 _Vf8($param, u16), _Vf9(u16, $param), _Vfa($param, u16), _Vfb(u16, $param),
324 _Vfc($param, u16), _Vfd(u16, $param), _Vfe($param, u16), _Vff(u16, $param),