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9fa01778 XL |
1 | //! Miscellaneous type-system utilities that are too small to deserve their own modules. |
2 | ||
f9f354fc | 3 | use crate::middle::codegen_fn_attrs::CodegenFnAttrFlags; |
ba9703b0 | 4 | use crate::ty::layout::IntegerExt; |
5099ac24 | 5 | use crate::ty::{ |
923072b8 | 6 | self, DefIdTree, FallibleTypeFolder, Ty, TyCtxt, TypeFoldable, TypeFolder, TypeSuperFoldable, |
064997fb | 7 | TypeVisitable, |
5099ac24 | 8 | }; |
2b03887a | 9 | use crate::ty::{GenericArgKind, SubstsRef}; |
dfeec247 | 10 | use rustc_apfloat::Float as _; |
0731742a | 11 | use rustc_data_structures::fx::{FxHashMap, FxHashSet}; |
dfeec247 | 12 | use rustc_data_structures::stable_hasher::{HashStable, StableHasher}; |
5e7ed085 | 13 | use rustc_errors::ErrorGuaranteed; |
dfeec247 | 14 | use rustc_hir as hir; |
5099ac24 | 15 | use rustc_hir::def::{CtorOf, DefKind, Res}; |
dfeec247 | 16 | use rustc_hir::def_id::DefId; |
923072b8 | 17 | use rustc_index::bit_set::GrowableBitSet; |
532ac7d7 | 18 | use rustc_macros::HashStable; |
5e7ed085 | 19 | use rustc_span::{sym, DUMMY_SP}; |
487cf647 | 20 | use rustc_target::abi::{Integer, IntegerType, Size, TargetDataLayout}; |
923072b8 | 21 | use rustc_target::spec::abi::Abi; |
74b04a01 | 22 | use smallvec::SmallVec; |
cdc7bbd5 | 23 | use std::{fmt, iter}; |
e9174d1e | 24 | |
0531ce1d XL |
25 | #[derive(Copy, Clone, Debug)] |
26 | pub struct Discr<'tcx> { | |
9fa01778 | 27 | /// Bit representation of the discriminant (e.g., `-128i8` is `0xFF_u128`). |
0531ce1d | 28 | pub val: u128, |
dfeec247 | 29 | pub ty: Ty<'tcx>, |
0531ce1d | 30 | } |
8bb4bdeb | 31 | |
923072b8 FG |
32 | /// Used as an input to [`TyCtxt::uses_unique_generic_params`]. |
33 | #[derive(Copy, Clone, Debug, PartialEq, Eq)] | |
34 | pub enum IgnoreRegions { | |
35 | Yes, | |
36 | No, | |
37 | } | |
38 | ||
39 | #[derive(Copy, Clone, Debug)] | |
40 | pub enum NotUniqueParam<'tcx> { | |
41 | DuplicateParam(ty::GenericArg<'tcx>), | |
42 | NotParam(ty::GenericArg<'tcx>), | |
43 | } | |
44 | ||
0531ce1d | 45 | impl<'tcx> fmt::Display for Discr<'tcx> { |
0bf4aa26 | 46 | fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result { |
1b1a35ee | 47 | match *self.ty.kind() { |
b7449926 | 48 | ty::Int(ity) => { |
5869c6ff | 49 | let size = ty::tls::with(|tcx| Integer::from_int_ty(&tcx, ity).size()); |
532ac7d7 | 50 | let x = self.val; |
0531ce1d | 51 | // sign extend the raw representation to be an i128 |
29967ef6 | 52 | let x = size.sign_extend(x) as i128; |
0531ce1d | 53 | write!(fmt, "{}", x) |
dfeec247 | 54 | } |
0531ce1d XL |
55 | _ => write!(fmt, "{}", self.val), |
56 | } | |
57 | } | |
cc61c64b | 58 | } |
8bb4bdeb | 59 | |
dfeec247 | 60 | fn int_size_and_signed<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> (Size, bool) { |
1b1a35ee | 61 | let (int, signed) = match *ty.kind() { |
923072b8 FG |
62 | ty::Int(ity) => (Integer::from_int_ty(&tcx, ity), true), |
63 | ty::Uint(uty) => (Integer::from_uint_ty(&tcx, uty), false), | |
dfeec247 XL |
64 | _ => bug!("non integer discriminant"), |
65 | }; | |
66 | (int.size(), signed) | |
67 | } | |
68 | ||
0531ce1d | 69 | impl<'tcx> Discr<'tcx> { |
9fa01778 | 70 | /// Adds `1` to the value and wraps around if the maximum for the type is reached. |
dc9dc135 | 71 | pub fn wrap_incr(self, tcx: TyCtxt<'tcx>) -> Self { |
0531ce1d XL |
72 | self.checked_add(tcx, 1).0 |
73 | } | |
dc9dc135 | 74 | pub fn checked_add(self, tcx: TyCtxt<'tcx>, n: u128) -> (Self, bool) { |
dfeec247 XL |
75 | let (size, signed) = int_size_and_signed(tcx, self.ty); |
76 | let (val, oflo) = if signed { | |
c295e0f8 XL |
77 | let min = size.signed_int_min(); |
78 | let max = size.signed_int_max(); | |
29967ef6 | 79 | let val = size.sign_extend(self.val) as i128; |
74b04a01 | 80 | assert!(n < (i128::MAX as u128)); |
0531ce1d XL |
81 | let n = n as i128; |
82 | let oflo = val > max - n; | |
dfeec247 | 83 | let val = if oflo { min + (n - (max - val) - 1) } else { val + n }; |
0531ce1d XL |
84 | // zero the upper bits |
85 | let val = val as u128; | |
29967ef6 | 86 | let val = size.truncate(val); |
dfeec247 | 87 | (val, oflo) |
0531ce1d | 88 | } else { |
c295e0f8 | 89 | let max = size.unsigned_int_max(); |
0531ce1d XL |
90 | let val = self.val; |
91 | let oflo = val > max - n; | |
dfeec247 XL |
92 | let val = if oflo { n - (max - val) - 1 } else { val + n }; |
93 | (val, oflo) | |
94 | }; | |
95 | (Self { val, ty: self.ty }, oflo) | |
8bb4bdeb | 96 | } |
e9174d1e SL |
97 | } |
98 | ||
0531ce1d | 99 | pub trait IntTypeExt { |
dc9dc135 XL |
100 | fn to_ty<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Ty<'tcx>; |
101 | fn disr_incr<'tcx>(&self, tcx: TyCtxt<'tcx>, val: Option<Discr<'tcx>>) -> Option<Discr<'tcx>>; | |
102 | fn initial_discriminant<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Discr<'tcx>; | |
0531ce1d XL |
103 | } |
104 | ||
487cf647 | 105 | impl IntTypeExt for IntegerType { |
dc9dc135 | 106 | fn to_ty<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> { |
487cf647 FG |
107 | match self { |
108 | IntegerType::Pointer(true) => tcx.types.isize, | |
109 | IntegerType::Pointer(false) => tcx.types.usize, | |
110 | IntegerType::Fixed(i, s) => i.to_ty(tcx, *s), | |
e9174d1e SL |
111 | } |
112 | } | |
113 | ||
dc9dc135 | 114 | fn initial_discriminant<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Discr<'tcx> { |
dfeec247 | 115 | Discr { val: 0, ty: self.to_ty(tcx) } |
e9174d1e SL |
116 | } |
117 | ||
dc9dc135 | 118 | fn disr_incr<'tcx>(&self, tcx: TyCtxt<'tcx>, val: Option<Discr<'tcx>>) -> Option<Discr<'tcx>> { |
a7813a04 | 119 | if let Some(val) = val { |
0531ce1d XL |
120 | assert_eq!(self.to_ty(tcx), val.ty); |
121 | let (new, oflo) = val.checked_add(tcx, 1); | |
dfeec247 | 122 | if oflo { None } else { Some(new) } |
a7813a04 XL |
123 | } else { |
124 | Some(self.initial_discriminant(tcx)) | |
125 | } | |
e9174d1e SL |
126 | } |
127 | } | |
128 | ||
dc9dc135 | 129 | impl<'tcx> TyCtxt<'tcx> { |
cc61c64b XL |
130 | /// Creates a hash of the type `Ty` which will be the same no matter what crate |
131 | /// context it's calculated within. This is used by the `type_id` intrinsic. | |
132 | pub fn type_id_hash(self, ty: Ty<'tcx>) -> u64 { | |
3b2f2976 XL |
133 | // We want the type_id be independent of the types free regions, so we |
134 | // erase them. The erase_regions() call will also anonymize bound | |
135 | // regions, which is desirable too. | |
fc512014 | 136 | let ty = self.erase_regions(ty); |
3b2f2976 | 137 | |
064997fb FG |
138 | self.with_stable_hashing_context(|mut hcx| { |
139 | let mut hasher = StableHasher::new(); | |
140 | hcx.while_hashing_spans(false, |hcx| ty.hash_stable(hcx, &mut hasher)); | |
141 | hasher.finish() | |
142 | }) | |
cc61c64b | 143 | } |
cc61c64b | 144 | |
5099ac24 FG |
145 | pub fn res_generics_def_id(self, res: Res) -> Option<DefId> { |
146 | match res { | |
147 | Res::Def(DefKind::Ctor(CtorOf::Variant, _), def_id) => { | |
04454e1e | 148 | Some(self.parent(self.parent(def_id))) |
5099ac24 FG |
149 | } |
150 | Res::Def(DefKind::Variant | DefKind::Ctor(CtorOf::Struct, _), def_id) => { | |
04454e1e | 151 | Some(self.parent(def_id)) |
5099ac24 FG |
152 | } |
153 | // Other `DefKind`s don't have generics and would ICE when calling | |
154 | // `generics_of`. | |
155 | Res::Def( | |
156 | DefKind::Struct | |
157 | | DefKind::Union | |
158 | | DefKind::Enum | |
159 | | DefKind::Trait | |
160 | | DefKind::OpaqueTy | |
161 | | DefKind::TyAlias | |
162 | | DefKind::ForeignTy | |
163 | | DefKind::TraitAlias | |
164 | | DefKind::AssocTy | |
165 | | DefKind::Fn | |
166 | | DefKind::AssocFn | |
167 | | DefKind::AssocConst | |
168 | | DefKind::Impl, | |
169 | def_id, | |
170 | ) => Some(def_id), | |
171 | Res::Err => None, | |
172 | _ => None, | |
173 | } | |
174 | } | |
175 | ||
5bcae85e | 176 | pub fn has_error_field(self, ty: Ty<'tcx>) -> bool { |
1b1a35ee | 177 | if let ty::Adt(def, substs) = *ty.kind() { |
0bf4aa26 XL |
178 | for field in def.all_fields() { |
179 | let field_ty = field.ty(self, substs); | |
923072b8 | 180 | if let ty::Error(_) = field_ty.kind() { |
0bf4aa26 | 181 | return true; |
5bcae85e SL |
182 | } |
183 | } | |
5bcae85e SL |
184 | } |
185 | false | |
186 | } | |
187 | ||
416331ca XL |
188 | /// Attempts to returns the deeply last field of nested structures, but |
189 | /// does not apply any normalization in its search. Returns the same type | |
190 | /// if input `ty` is not a structure at all. | |
dfeec247 | 191 | pub fn struct_tail_without_normalization(self, ty: Ty<'tcx>) -> Ty<'tcx> { |
416331ca | 192 | let tcx = self; |
04454e1e | 193 | tcx.struct_tail_with_normalize(ty, |ty| ty, || {}) |
416331ca XL |
194 | } |
195 | ||
196 | /// Returns the deeply last field of nested structures, or the same type if | |
197 | /// not a structure at all. Corresponds to the only possible unsized field, | |
198 | /// and its type can be used to determine unsizing strategy. | |
199 | /// | |
200 | /// Should only be called if `ty` has no inference variables and does not | |
201 | /// need its lifetimes preserved (e.g. as part of codegen); otherwise | |
202 | /// normalization attempt may cause compiler bugs. | |
dfeec247 XL |
203 | pub fn struct_tail_erasing_lifetimes( |
204 | self, | |
205 | ty: Ty<'tcx>, | |
206 | param_env: ty::ParamEnv<'tcx>, | |
207 | ) -> Ty<'tcx> { | |
416331ca | 208 | let tcx = self; |
04454e1e | 209 | tcx.struct_tail_with_normalize(ty, |ty| tcx.normalize_erasing_regions(param_env, ty), || {}) |
416331ca XL |
210 | } |
211 | ||
212 | /// Returns the deeply last field of nested structures, or the same type if | |
213 | /// not a structure at all. Corresponds to the only possible unsized field, | |
214 | /// and its type can be used to determine unsizing strategy. | |
215 | /// | |
216 | /// This is parameterized over the normalization strategy (i.e. how to | |
217 | /// handle `<T as Trait>::Assoc` and `impl Trait`); pass the identity | |
218 | /// function to indicate no normalization should take place. | |
219 | /// | |
220 | /// See also `struct_tail_erasing_lifetimes`, which is suitable for use | |
221 | /// during codegen. | |
dfeec247 XL |
222 | pub fn struct_tail_with_normalize( |
223 | self, | |
224 | mut ty: Ty<'tcx>, | |
5099ac24 | 225 | mut normalize: impl FnMut(Ty<'tcx>) -> Ty<'tcx>, |
04454e1e FG |
226 | // This is currently used to allow us to walk a ValTree |
227 | // in lockstep with the type in order to get the ValTree branch that | |
228 | // corresponds to an unsized field. | |
229 | mut f: impl FnMut() -> (), | |
dfeec247 | 230 | ) -> Ty<'tcx> { |
136023e0 | 231 | let recursion_limit = self.recursion_limit(); |
fc512014 | 232 | for iteration in 0.. { |
136023e0 | 233 | if !recursion_limit.value_within_limit(iteration) { |
fc512014 XL |
234 | return self.ty_error_with_message( |
235 | DUMMY_SP, | |
236 | &format!("reached the recursion limit finding the struct tail for {}", ty), | |
237 | ); | |
238 | } | |
1b1a35ee | 239 | match *ty.kind() { |
b7449926 | 240 | ty::Adt(def, substs) => { |
7cac9316 XL |
241 | if !def.is_struct() { |
242 | break; | |
243 | } | |
2c00a5a8 | 244 | match def.non_enum_variant().fields.last() { |
04454e1e FG |
245 | Some(field) => { |
246 | f(); | |
247 | ty = field.ty(self, substs); | |
248 | } | |
7cac9316 XL |
249 | None => break, |
250 | } | |
251 | } | |
252 | ||
94222f64 | 253 | ty::Tuple(tys) if let Some((&last_ty, _)) = tys.split_last() => { |
04454e1e | 254 | f(); |
5e7ed085 | 255 | ty = last_ty; |
7cac9316 XL |
256 | } |
257 | ||
94222f64 XL |
258 | ty::Tuple(_) => break, |
259 | ||
416331ca XL |
260 | ty::Projection(_) | ty::Opaque(..) => { |
261 | let normalized = normalize(ty); | |
262 | if ty == normalized { | |
263 | return ty; | |
264 | } else { | |
265 | ty = normalized; | |
266 | } | |
267 | } | |
268 | ||
7cac9316 XL |
269 | _ => { |
270 | break; | |
271 | } | |
e9174d1e SL |
272 | } |
273 | } | |
274 | ty | |
275 | } | |
276 | ||
60c5eb7d | 277 | /// Same as applying `struct_tail` on `source` and `target`, but only |
e9174d1e SL |
278 | /// keeps going as long as the two types are instances of the same |
279 | /// structure definitions. | |
a1dfa0c6 | 280 | /// For `(Foo<Foo<T>>, Foo<dyn Trait>)`, the result will be `(Foo<T>, Trait)`, |
e9174d1e | 281 | /// whereas struct_tail produces `T`, and `Trait`, respectively. |
416331ca XL |
282 | /// |
283 | /// Should only be called if the types have no inference variables and do | |
60c5eb7d | 284 | /// not need their lifetimes preserved (e.g., as part of codegen); otherwise, |
416331ca | 285 | /// normalization attempt may cause compiler bugs. |
dfeec247 XL |
286 | pub fn struct_lockstep_tails_erasing_lifetimes( |
287 | self, | |
288 | source: Ty<'tcx>, | |
289 | target: Ty<'tcx>, | |
290 | param_env: ty::ParamEnv<'tcx>, | |
291 | ) -> (Ty<'tcx>, Ty<'tcx>) { | |
416331ca | 292 | let tcx = self; |
dfeec247 XL |
293 | tcx.struct_lockstep_tails_with_normalize(source, target, |ty| { |
294 | tcx.normalize_erasing_regions(param_env, ty) | |
295 | }) | |
416331ca XL |
296 | } |
297 | ||
60c5eb7d | 298 | /// Same as applying `struct_tail` on `source` and `target`, but only |
416331ca XL |
299 | /// keeps going as long as the two types are instances of the same |
300 | /// structure definitions. | |
301 | /// For `(Foo<Foo<T>>, Foo<dyn Trait>)`, the result will be `(Foo<T>, Trait)`, | |
302 | /// whereas struct_tail produces `T`, and `Trait`, respectively. | |
303 | /// | |
304 | /// See also `struct_lockstep_tails_erasing_lifetimes`, which is suitable for use | |
305 | /// during codegen. | |
dfeec247 XL |
306 | pub fn struct_lockstep_tails_with_normalize( |
307 | self, | |
308 | source: Ty<'tcx>, | |
309 | target: Ty<'tcx>, | |
310 | normalize: impl Fn(Ty<'tcx>) -> Ty<'tcx>, | |
311 | ) -> (Ty<'tcx>, Ty<'tcx>) { | |
e9174d1e | 312 | let (mut a, mut b) = (source, target); |
041b39d2 | 313 | loop { |
1b1a35ee | 314 | match (&a.kind(), &b.kind()) { |
923072b8 | 315 | (&ty::Adt(a_def, a_substs), &ty::Adt(b_def, b_substs)) |
dfeec247 XL |
316 | if a_def == b_def && a_def.is_struct() => |
317 | { | |
2c00a5a8 | 318 | if let Some(f) = a_def.non_enum_variant().fields.last() { |
041b39d2 XL |
319 | a = f.ty(self, a_substs); |
320 | b = f.ty(self, b_substs); | |
321 | } else { | |
322 | break; | |
323 | } | |
dfeec247 | 324 | } |
923072b8 | 325 | (&ty::Tuple(a_tys), &ty::Tuple(b_tys)) if a_tys.len() == b_tys.len() => { |
5e7ed085 FG |
326 | if let Some(&a_last) = a_tys.last() { |
327 | a = a_last; | |
328 | b = *b_tys.last().unwrap(); | |
041b39d2 XL |
329 | } else { |
330 | break; | |
331 | } | |
dfeec247 | 332 | } |
ba9703b0 XL |
333 | (ty::Projection(_) | ty::Opaque(..), _) |
334 | | (_, ty::Projection(_) | ty::Opaque(..)) => { | |
416331ca XL |
335 | // If either side is a projection, attempt to |
336 | // progress via normalization. (Should be safe to | |
337 | // apply to both sides as normalization is | |
338 | // idempotent.) | |
339 | let a_norm = normalize(a); | |
340 | let b_norm = normalize(b); | |
341 | if a == a_norm && b == b_norm { | |
342 | break; | |
343 | } else { | |
344 | a = a_norm; | |
345 | b = b_norm; | |
346 | } | |
347 | } | |
348 | ||
cc61c64b | 349 | _ => break, |
e9174d1e SL |
350 | } |
351 | } | |
352 | (a, b) | |
353 | } | |
354 | ||
8bb4bdeb XL |
355 | /// Calculate the destructor of a given type. |
356 | pub fn calculate_dtor( | |
357 | self, | |
358 | adt_did: DefId, | |
5e7ed085 | 359 | validate: impl Fn(Self, DefId) -> Result<(), ErrorGuaranteed>, |
8bb4bdeb | 360 | ) -> Option<ty::Destructor> { |
ba9703b0 | 361 | let drop_trait = self.lang_items().drop_trait()?; |
9fa01778 | 362 | self.ensure().coherent_trait(drop_trait); |
8bb4bdeb | 363 | |
7cac9316 | 364 | let ty = self.type_of(adt_did); |
c295e0f8 | 365 | let (did, constness) = self.find_map_relevant_impl(drop_trait, ty, |impl_did| { |
3c0e092e | 366 | if let Some(item_id) = self.associated_item_def_ids(impl_did).first() { |
0bf4aa26 | 367 | if validate(self, impl_did).is_ok() { |
923072b8 | 368 | return Some((*item_id, self.constness(impl_did))); |
8bb4bdeb XL |
369 | } |
370 | } | |
29967ef6 | 371 | None |
c295e0f8 | 372 | })?; |
8bb4bdeb | 373 | |
c295e0f8 | 374 | Some(ty::Destructor { did, constness }) |
cc61c64b XL |
375 | } |
376 | ||
9fa01778 | 377 | /// Returns the set of types that are required to be alive in |
cc61c64b XL |
378 | /// order to run the destructor of `def` (see RFCs 769 and |
379 | /// 1238). | |
380 | /// | |
381 | /// Note that this returns only the constraints for the | |
382 | /// destructor of `def` itself. For the destructors of the | |
383 | /// contents, you need `adt_dtorck_constraint`. | |
5e7ed085 | 384 | pub fn destructor_constraints(self, def: ty::AdtDef<'tcx>) -> Vec<ty::subst::GenericArg<'tcx>> { |
cc61c64b XL |
385 | let dtor = match def.destructor(self) { |
386 | None => { | |
5e7ed085 | 387 | debug!("destructor_constraints({:?}) - no dtor", def.did()); |
dfeec247 | 388 | return vec![]; |
cc61c64b | 389 | } |
dfeec247 | 390 | Some(dtor) => dtor.did, |
e9174d1e | 391 | }; |
b039eaaf | 392 | |
064997fb | 393 | let impl_def_id = self.parent(dtor); |
7cac9316 | 394 | let impl_generics = self.generics_of(impl_def_id); |
cc61c64b XL |
395 | |
396 | // We have a destructor - all the parameters that are not | |
397 | // pure_wrt_drop (i.e, don't have a #[may_dangle] attribute) | |
398 | // must be live. | |
399 | ||
400 | // We need to return the list of parameters from the ADTs | |
401 | // generics/substs that correspond to impure parameters on the | |
402 | // impl's generics. This is a bit ugly, but conceptually simple: | |
403 | // | |
404 | // Suppose our ADT looks like the following | |
405 | // | |
406 | // struct S<X, Y, Z>(X, Y, Z); | |
407 | // | |
408 | // and the impl is | |
409 | // | |
410 | // impl<#[may_dangle] P0, P1, P2> Drop for S<P1, P2, P0> | |
411 | // | |
412 | // We want to return the parameters (X, Y). For that, we match | |
413 | // up the item-substs <X, Y, Z> with the substs on the impl ADT, | |
414 | // <P1, P2, P0>, and then look up which of the impl substs refer to | |
415 | // parameters marked as pure. | |
416 | ||
1b1a35ee | 417 | let impl_substs = match *self.type_of(impl_def_id).kind() { |
b7449926 | 418 | ty::Adt(def_, substs) if def_ == def => substs, |
dfeec247 | 419 | _ => bug!(), |
cc61c64b XL |
420 | }; |
421 | ||
5e7ed085 | 422 | let item_substs = match *self.type_of(def.did()).kind() { |
b7449926 | 423 | ty::Adt(def_, substs) if def_ == def => substs, |
dfeec247 | 424 | _ => bug!(), |
cc61c64b XL |
425 | }; |
426 | ||
cdc7bbd5 | 427 | let result = iter::zip(item_substs, impl_substs) |
f9f354fc | 428 | .filter(|&(_, k)| { |
0531ce1d | 429 | match k.unpack() { |
04454e1e | 430 | GenericArgKind::Lifetime(region) => match region.kind() { |
923072b8 | 431 | ty::ReEarlyBound(ref ebr) => { |
04454e1e FG |
432 | !impl_generics.region_param(ebr, self).pure_wrt_drop |
433 | } | |
434 | // Error: not a region param | |
435 | _ => false, | |
436 | }, | |
437 | GenericArgKind::Type(ty) => match ty.kind() { | |
438 | ty::Param(ref pt) => !impl_generics.type_param(pt, self).pure_wrt_drop, | |
439 | // Error: not a type param | |
440 | _ => false, | |
441 | }, | |
923072b8 | 442 | GenericArgKind::Const(ct) => match ct.kind() { |
04454e1e FG |
443 | ty::ConstKind::Param(ref pc) => { |
444 | !impl_generics.const_param(pc, self).pure_wrt_drop | |
445 | } | |
446 | // Error: not a const param | |
447 | _ => false, | |
448 | }, | |
cc61c64b | 449 | } |
0bf4aa26 | 450 | }) |
f9f354fc | 451 | .map(|(item_param, _)| item_param) |
0bf4aa26 | 452 | .collect(); |
5e7ed085 | 453 | debug!("destructor_constraint({:?}) = {:?}", def.did(), result); |
cc61c64b | 454 | result |
b039eaaf | 455 | } |
9e0c209e | 456 | |
923072b8 FG |
457 | /// Checks whether each generic argument is simply a unique generic parameter. |
458 | pub fn uses_unique_generic_params( | |
459 | self, | |
460 | substs: SubstsRef<'tcx>, | |
461 | ignore_regions: IgnoreRegions, | |
462 | ) -> Result<(), NotUniqueParam<'tcx>> { | |
463 | let mut seen = GrowableBitSet::default(); | |
464 | for arg in substs { | |
465 | match arg.unpack() { | |
466 | GenericArgKind::Lifetime(lt) => { | |
467 | if ignore_regions == IgnoreRegions::No { | |
468 | let ty::ReEarlyBound(p) = lt.kind() else { | |
469 | return Err(NotUniqueParam::NotParam(lt.into())) | |
470 | }; | |
471 | if !seen.insert(p.index) { | |
472 | return Err(NotUniqueParam::DuplicateParam(lt.into())); | |
473 | } | |
474 | } | |
475 | } | |
476 | GenericArgKind::Type(t) => match t.kind() { | |
477 | ty::Param(p) => { | |
478 | if !seen.insert(p.index) { | |
479 | return Err(NotUniqueParam::DuplicateParam(t.into())); | |
480 | } | |
481 | } | |
482 | _ => return Err(NotUniqueParam::NotParam(t.into())), | |
483 | }, | |
484 | GenericArgKind::Const(c) => match c.kind() { | |
485 | ty::ConstKind::Param(p) => { | |
486 | if !seen.insert(p.index) { | |
487 | return Err(NotUniqueParam::DuplicateParam(c.into())); | |
488 | } | |
489 | } | |
490 | _ => return Err(NotUniqueParam::NotParam(c.into())), | |
491 | }, | |
492 | } | |
493 | } | |
494 | ||
495 | Ok(()) | |
496 | } | |
497 | ||
9fa01778 XL |
498 | /// Returns `true` if `def_id` refers to a closure (e.g., `|x| x * 2`). Note |
499 | /// that closures have a `DefId`, but the closure *expression* also | |
8faf50e0 XL |
500 | /// has a `HirId` that is located within the context where the |
501 | /// closure appears (and, sadly, a corresponding `NodeId`, since | |
502 | /// those are not yet phased out). The parent of the closure's | |
9fa01778 | 503 | /// `DefId` will also be the context where it appears. |
abe05a73 | 504 | pub fn is_closure(self, def_id: DefId) -> bool { |
f9f354fc | 505 | matches!(self.def_kind(def_id), DefKind::Closure | DefKind::Generator) |
abe05a73 XL |
506 | } |
507 | ||
3c0e092e XL |
508 | /// Returns `true` if `def_id` refers to a definition that does not have its own |
509 | /// type-checking context, i.e. closure, generator or inline const. | |
510 | pub fn is_typeck_child(self, def_id: DefId) -> bool { | |
511 | matches!( | |
512 | self.def_kind(def_id), | |
513 | DefKind::Closure | DefKind::Generator | DefKind::InlineConst | |
514 | ) | |
515 | } | |
516 | ||
9fa01778 | 517 | /// Returns `true` if `def_id` refers to a trait (i.e., `trait Foo { ... }`). |
8faf50e0 | 518 | pub fn is_trait(self, def_id: DefId) -> bool { |
f9f354fc | 519 | self.def_kind(def_id) == DefKind::Trait |
8faf50e0 XL |
520 | } |
521 | ||
9fa01778 XL |
522 | /// Returns `true` if `def_id` refers to a trait alias (i.e., `trait Foo = ...;`), |
523 | /// and `false` otherwise. | |
524 | pub fn is_trait_alias(self, def_id: DefId) -> bool { | |
f9f354fc | 525 | self.def_kind(def_id) == DefKind::TraitAlias |
9fa01778 XL |
526 | } |
527 | ||
528 | /// Returns `true` if this `DefId` refers to the implicit constructor for | |
529 | /// a tuple struct like `struct Foo(u32)`, and `false` otherwise. | |
532ac7d7 | 530 | pub fn is_constructor(self, def_id: DefId) -> bool { |
f9f354fc | 531 | matches!(self.def_kind(def_id), DefKind::Ctor(..)) |
8faf50e0 XL |
532 | } |
533 | ||
3c0e092e | 534 | /// Given the `DefId`, returns the `DefId` of the innermost item that |
5e7ed085 | 535 | /// has its own type-checking context or "inference environment". |
3c0e092e XL |
536 | /// |
537 | /// For example, a closure has its own `DefId`, but it is type-checked | |
538 | /// with the containing item. Similarly, an inline const block has its | |
539 | /// own `DefId` but it is type-checked together with the containing item. | |
540 | /// | |
541 | /// Therefore, when we fetch the | |
3dfed10e XL |
542 | /// `typeck` the closure, for example, we really wind up |
543 | /// fetching the `typeck` the enclosing fn item. | |
3c0e092e | 544 | pub fn typeck_root_def_id(self, def_id: DefId) -> DefId { |
476ff2be | 545 | let mut def_id = def_id; |
3c0e092e | 546 | while self.is_typeck_child(def_id) { |
04454e1e | 547 | def_id = self.parent(def_id); |
476ff2be SL |
548 | } |
549 | def_id | |
9e0c209e | 550 | } |
cc61c64b | 551 | |
9fa01778 | 552 | /// Given the `DefId` and substs a closure, creates the type of |
ff7c6d11 XL |
553 | /// `self` argument that the closure expects. For example, for a |
554 | /// `Fn` closure, this would return a reference type `&T` where | |
9fa01778 | 555 | /// `T = closure_ty`. |
ff7c6d11 XL |
556 | /// |
557 | /// Returns `None` if this closure's kind has not yet been inferred. | |
558 | /// This should only be possible during type checking. | |
559 | /// | |
560 | /// Note that the return value is a late-bound region and hence | |
561 | /// wrapped in a binder. | |
dfeec247 XL |
562 | pub fn closure_env_ty( |
563 | self, | |
564 | closure_def_id: DefId, | |
565 | closure_substs: SubstsRef<'tcx>, | |
923072b8 | 566 | env_region: ty::RegionKind<'tcx>, |
cdc7bbd5 | 567 | ) -> Option<Ty<'tcx>> { |
ff7c6d11 | 568 | let closure_ty = self.mk_closure(closure_def_id, closure_substs); |
ba9703b0 | 569 | let closure_kind_ty = closure_substs.as_closure().kind_ty(); |
ff7c6d11 XL |
570 | let closure_kind = closure_kind_ty.to_opt_closure_kind()?; |
571 | let env_ty = match closure_kind { | |
572 | ty::ClosureKind::Fn => self.mk_imm_ref(self.mk_region(env_region), closure_ty), | |
573 | ty::ClosureKind::FnMut => self.mk_mut_ref(self.mk_region(env_region), closure_ty), | |
574 | ty::ClosureKind::FnOnce => closure_ty, | |
575 | }; | |
cdc7bbd5 | 576 | Some(env_ty) |
ff7c6d11 XL |
577 | } |
578 | ||
48663c56 | 579 | /// Returns `true` if the node pointed to by `def_id` is a `static` item. |
5e7ed085 | 580 | #[inline] |
1b1a35ee | 581 | pub fn is_static(self, def_id: DefId) -> bool { |
5e7ed085 FG |
582 | matches!(self.def_kind(def_id), DefKind::Static(_)) |
583 | } | |
584 | ||
585 | #[inline] | |
586 | pub fn static_mutability(self, def_id: DefId) -> Option<hir::Mutability> { | |
587 | if let DefKind::Static(mt) = self.def_kind(def_id) { Some(mt) } else { None } | |
48663c56 XL |
588 | } |
589 | ||
f9f354fc | 590 | /// Returns `true` if this is a `static` item with the `#[thread_local]` attribute. |
1b1a35ee | 591 | pub fn is_thread_local_static(self, def_id: DefId) -> bool { |
f9f354fc XL |
592 | self.codegen_fn_attrs(def_id).flags.contains(CodegenFnAttrFlags::THREAD_LOCAL) |
593 | } | |
594 | ||
48663c56 | 595 | /// Returns `true` if the node pointed to by `def_id` is a mutable `static` item. |
5e7ed085 | 596 | #[inline] |
1b1a35ee | 597 | pub fn is_mutable_static(self, def_id: DefId) -> bool { |
dfeec247 | 598 | self.static_mutability(def_id) == Some(hir::Mutability::Mut) |
60c5eb7d XL |
599 | } |
600 | ||
601 | /// Get the type of the pointer to the static that we use in MIR. | |
1b1a35ee | 602 | pub fn static_ptr_ty(self, def_id: DefId) -> Ty<'tcx> { |
60c5eb7d | 603 | // Make sure that any constants in the static's type are evaluated. |
dfeec247 | 604 | let static_ty = self.normalize_erasing_regions(ty::ParamEnv::empty(), self.type_of(def_id)); |
60c5eb7d | 605 | |
29967ef6 XL |
606 | // Make sure that accesses to unsafe statics end up using raw pointers. |
607 | // For thread-locals, this needs to be kept in sync with `Rvalue::ty`. | |
60c5eb7d XL |
608 | if self.is_mutable_static(def_id) { |
609 | self.mk_mut_ptr(static_ty) | |
29967ef6 XL |
610 | } else if self.is_foreign_item(def_id) { |
611 | self.mk_imm_ptr(static_ty) | |
60c5eb7d XL |
612 | } else { |
613 | self.mk_imm_ref(self.lifetimes.re_erased, static_ty) | |
614 | } | |
abe05a73 | 615 | } |
0731742a XL |
616 | |
617 | /// Expands the given impl trait type, stopping if the type is recursive. | |
f2b60f7d | 618 | #[instrument(skip(self), level = "debug", ret)] |
0731742a XL |
619 | pub fn try_expand_impl_trait_type( |
620 | self, | |
621 | def_id: DefId, | |
532ac7d7 | 622 | substs: SubstsRef<'tcx>, |
0731742a | 623 | ) -> Result<Ty<'tcx>, Ty<'tcx>> { |
0731742a XL |
624 | let mut visitor = OpaqueTypeExpander { |
625 | seen_opaque_tys: FxHashSet::default(), | |
e1599b0c | 626 | expanded_cache: FxHashMap::default(), |
3dfed10e | 627 | primary_def_id: Some(def_id), |
0731742a | 628 | found_recursion: false, |
94222f64 | 629 | found_any_recursion: false, |
3dfed10e | 630 | check_recursion: true, |
0731742a XL |
631 | tcx: self, |
632 | }; | |
3dfed10e | 633 | |
0731742a | 634 | let expanded_type = visitor.expand_opaque_ty(def_id, substs).unwrap(); |
dfeec247 | 635 | if visitor.found_recursion { Err(expanded_type) } else { Ok(expanded_type) } |
0731742a | 636 | } |
04454e1e | 637 | |
923072b8 FG |
638 | pub fn bound_type_of(self, def_id: DefId) -> ty::EarlyBinder<Ty<'tcx>> { |
639 | ty::EarlyBinder(self.type_of(def_id)) | |
04454e1e FG |
640 | } |
641 | ||
f2b60f7d FG |
642 | pub fn bound_trait_impl_trait_tys( |
643 | self, | |
644 | def_id: DefId, | |
645 | ) -> ty::EarlyBinder<Result<&'tcx FxHashMap<DefId, Ty<'tcx>>, ErrorGuaranteed>> { | |
646 | ty::EarlyBinder(self.collect_trait_impl_trait_tys(def_id)) | |
647 | } | |
648 | ||
923072b8 FG |
649 | pub fn bound_fn_sig(self, def_id: DefId) -> ty::EarlyBinder<ty::PolyFnSig<'tcx>> { |
650 | ty::EarlyBinder(self.fn_sig(def_id)) | |
04454e1e FG |
651 | } |
652 | ||
923072b8 FG |
653 | pub fn bound_impl_trait_ref( |
654 | self, | |
655 | def_id: DefId, | |
656 | ) -> Option<ty::EarlyBinder<ty::TraitRef<'tcx>>> { | |
657 | self.impl_trait_ref(def_id).map(|i| ty::EarlyBinder(i)) | |
04454e1e FG |
658 | } |
659 | ||
660 | pub fn bound_explicit_item_bounds( | |
661 | self, | |
662 | def_id: DefId, | |
923072b8 FG |
663 | ) -> ty::EarlyBinder<&'tcx [(ty::Predicate<'tcx>, rustc_span::Span)]> { |
664 | ty::EarlyBinder(self.explicit_item_bounds(def_id)) | |
04454e1e FG |
665 | } |
666 | ||
667 | pub fn bound_item_bounds( | |
668 | self, | |
669 | def_id: DefId, | |
923072b8 FG |
670 | ) -> ty::EarlyBinder<&'tcx ty::List<ty::Predicate<'tcx>>> { |
671 | ty::EarlyBinder(self.item_bounds(def_id)) | |
04454e1e | 672 | } |
064997fb FG |
673 | |
674 | pub fn bound_const_param_default(self, def_id: DefId) -> ty::EarlyBinder<ty::Const<'tcx>> { | |
675 | ty::EarlyBinder(self.const_param_default(def_id)) | |
676 | } | |
677 | ||
678 | pub fn bound_predicates_of( | |
679 | self, | |
680 | def_id: DefId, | |
681 | ) -> ty::EarlyBinder<ty::generics::GenericPredicates<'tcx>> { | |
682 | ty::EarlyBinder(self.predicates_of(def_id)) | |
683 | } | |
684 | ||
685 | pub fn bound_explicit_predicates_of( | |
686 | self, | |
687 | def_id: DefId, | |
688 | ) -> ty::EarlyBinder<ty::generics::GenericPredicates<'tcx>> { | |
689 | ty::EarlyBinder(self.explicit_predicates_of(def_id)) | |
690 | } | |
691 | ||
692 | pub fn bound_impl_subject(self, def_id: DefId) -> ty::EarlyBinder<ty::ImplSubject<'tcx>> { | |
693 | ty::EarlyBinder(self.impl_subject(def_id)) | |
694 | } | |
9e0c209e SL |
695 | } |
696 | ||
3dfed10e XL |
697 | struct OpaqueTypeExpander<'tcx> { |
698 | // Contains the DefIds of the opaque types that are currently being | |
699 | // expanded. When we expand an opaque type we insert the DefId of | |
700 | // that type, and when we finish expanding that type we remove the | |
701 | // its DefId. | |
702 | seen_opaque_tys: FxHashSet<DefId>, | |
703 | // Cache of all expansions we've seen so far. This is a critical | |
704 | // optimization for some large types produced by async fn trees. | |
705 | expanded_cache: FxHashMap<(DefId, SubstsRef<'tcx>), Ty<'tcx>>, | |
706 | primary_def_id: Option<DefId>, | |
707 | found_recursion: bool, | |
94222f64 | 708 | found_any_recursion: bool, |
3dfed10e XL |
709 | /// Whether or not to check for recursive opaque types. |
710 | /// This is `true` when we're explicitly checking for opaque type | |
711 | /// recursion, and 'false' otherwise to avoid unnecessary work. | |
712 | check_recursion: bool, | |
713 | tcx: TyCtxt<'tcx>, | |
714 | } | |
715 | ||
716 | impl<'tcx> OpaqueTypeExpander<'tcx> { | |
717 | fn expand_opaque_ty(&mut self, def_id: DefId, substs: SubstsRef<'tcx>) -> Option<Ty<'tcx>> { | |
94222f64 | 718 | if self.found_any_recursion { |
3dfed10e XL |
719 | return None; |
720 | } | |
721 | let substs = substs.fold_with(self); | |
722 | if !self.check_recursion || self.seen_opaque_tys.insert(def_id) { | |
723 | let expanded_ty = match self.expanded_cache.get(&(def_id, substs)) { | |
5099ac24 | 724 | Some(expanded_ty) => *expanded_ty, |
3dfed10e | 725 | None => { |
04454e1e | 726 | let generic_ty = self.tcx.bound_type_of(def_id); |
3dfed10e XL |
727 | let concrete_ty = generic_ty.subst(self.tcx, substs); |
728 | let expanded_ty = self.fold_ty(concrete_ty); | |
729 | self.expanded_cache.insert((def_id, substs), expanded_ty); | |
730 | expanded_ty | |
731 | } | |
732 | }; | |
733 | if self.check_recursion { | |
734 | self.seen_opaque_tys.remove(&def_id); | |
735 | } | |
736 | Some(expanded_ty) | |
737 | } else { | |
738 | // If another opaque type that we contain is recursive, then it | |
739 | // will report the error, so we don't have to. | |
94222f64 | 740 | self.found_any_recursion = true; |
3dfed10e XL |
741 | self.found_recursion = def_id == *self.primary_def_id.as_ref().unwrap(); |
742 | None | |
743 | } | |
744 | } | |
745 | } | |
746 | ||
747 | impl<'tcx> TypeFolder<'tcx> for OpaqueTypeExpander<'tcx> { | |
748 | fn tcx(&self) -> TyCtxt<'tcx> { | |
749 | self.tcx | |
750 | } | |
751 | ||
752 | fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> { | |
5099ac24 | 753 | if let ty::Opaque(def_id, substs) = *t.kind() { |
3dfed10e XL |
754 | self.expand_opaque_ty(def_id, substs).unwrap_or(t) |
755 | } else if t.has_opaque_types() { | |
756 | t.super_fold_with(self) | |
757 | } else { | |
758 | t | |
759 | } | |
760 | } | |
761 | } | |
762 | ||
5099ac24 | 763 | impl<'tcx> Ty<'tcx> { |
dfeec247 XL |
764 | /// Returns the maximum value for the given numeric type (including `char`s) |
765 | /// or returns `None` if the type is not numeric. | |
923072b8 | 766 | pub fn numeric_max_val(self, tcx: TyCtxt<'tcx>) -> Option<ty::Const<'tcx>> { |
1b1a35ee | 767 | let val = match self.kind() { |
dfeec247 XL |
768 | ty::Int(_) | ty::Uint(_) => { |
769 | let (size, signed) = int_size_and_signed(tcx, self); | |
c295e0f8 XL |
770 | let val = |
771 | if signed { size.signed_int_max() as u128 } else { size.unsigned_int_max() }; | |
dfeec247 XL |
772 | Some(val) |
773 | } | |
774 | ty::Char => Some(std::char::MAX as u128), | |
775 | ty::Float(fty) => Some(match fty { | |
5869c6ff XL |
776 | ty::FloatTy::F32 => rustc_apfloat::ieee::Single::INFINITY.to_bits(), |
777 | ty::FloatTy::F64 => rustc_apfloat::ieee::Double::INFINITY.to_bits(), | |
dfeec247 XL |
778 | }), |
779 | _ => None, | |
780 | }; | |
923072b8 FG |
781 | |
782 | val.map(|v| ty::Const::from_bits(tcx, v, ty::ParamEnv::empty().and(self))) | |
dfeec247 XL |
783 | } |
784 | ||
785 | /// Returns the minimum value for the given numeric type (including `char`s) | |
786 | /// or returns `None` if the type is not numeric. | |
923072b8 | 787 | pub fn numeric_min_val(self, tcx: TyCtxt<'tcx>) -> Option<ty::Const<'tcx>> { |
1b1a35ee | 788 | let val = match self.kind() { |
dfeec247 XL |
789 | ty::Int(_) | ty::Uint(_) => { |
790 | let (size, signed) = int_size_and_signed(tcx, self); | |
c295e0f8 | 791 | let val = if signed { size.truncate(size.signed_int_min() as u128) } else { 0 }; |
dfeec247 XL |
792 | Some(val) |
793 | } | |
794 | ty::Char => Some(0), | |
795 | ty::Float(fty) => Some(match fty { | |
5869c6ff XL |
796 | ty::FloatTy::F32 => (-::rustc_apfloat::ieee::Single::INFINITY).to_bits(), |
797 | ty::FloatTy::F64 => (-::rustc_apfloat::ieee::Double::INFINITY).to_bits(), | |
dfeec247 XL |
798 | }), |
799 | _ => None, | |
800 | }; | |
923072b8 FG |
801 | |
802 | val.map(|v| ty::Const::from_bits(tcx, v, ty::ParamEnv::empty().and(self))) | |
dfeec247 XL |
803 | } |
804 | ||
0731742a XL |
805 | /// Checks whether values of this type `T` are *moved* or *copied* |
806 | /// when referenced -- this amounts to a check for whether `T: | |
807 | /// Copy`, but note that we **don't** consider lifetimes when | |
808 | /// doing this check. This means that we may generate MIR which | |
809 | /// does copies even when the type actually doesn't satisfy the | |
810 | /// full requirements for the `Copy` trait (cc #29149) -- this | |
811 | /// winds up being reported as an error during NLL borrow check. | |
2b03887a FG |
812 | pub fn is_copy_modulo_regions(self, tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> bool { |
813 | self.is_trivially_pure_clone_copy() || tcx.is_copy_raw(param_env.and(self)) | |
e9174d1e SL |
814 | } |
815 | ||
0731742a XL |
816 | /// Checks whether values of this type `T` have a size known at |
817 | /// compile time (i.e., whether `T: Sized`). Lifetimes are ignored | |
818 | /// for the purposes of this check, so it can be an | |
819 | /// over-approximation in generic contexts, where one can have | |
820 | /// strange rules like `<T as Foo<'static>>::Bar: Sized` that | |
821 | /// actually carry lifetime requirements. | |
2b03887a FG |
822 | pub fn is_sized(self, tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> bool { |
823 | self.is_trivially_sized(tcx) || tcx.is_sized_raw(param_env.and(self)) | |
e9174d1e SL |
824 | } |
825 | ||
0731742a | 826 | /// Checks whether values of this type `T` implement the `Freeze` |
94222f64 | 827 | /// trait -- frozen types are those that do not contain an |
9fa01778 | 828 | /// `UnsafeCell` anywhere. This is a language concept used to |
0731742a XL |
829 | /// distinguish "true immutability", which is relevant to |
830 | /// optimization as well as the rules around static values. Note | |
831 | /// that the `Freeze` trait is not exposed to end users and is | |
832 | /// effectively an implementation detail. | |
2b03887a FG |
833 | pub fn is_freeze(self, tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> bool { |
834 | self.is_trivially_freeze() || tcx.is_freeze_raw(param_env.and(self)) | |
74b04a01 XL |
835 | } |
836 | ||
837 | /// Fast path helper for testing if a type is `Freeze`. | |
838 | /// | |
839 | /// Returning true means the type is known to be `Freeze`. Returning | |
840 | /// `false` means nothing -- could be `Freeze`, might not be. | |
5099ac24 | 841 | fn is_trivially_freeze(self) -> bool { |
1b1a35ee | 842 | match self.kind() { |
74b04a01 XL |
843 | ty::Int(_) |
844 | | ty::Uint(_) | |
845 | | ty::Float(_) | |
846 | | ty::Bool | |
847 | | ty::Char | |
848 | | ty::Str | |
849 | | ty::Never | |
850 | | ty::Ref(..) | |
851 | | ty::RawPtr(_) | |
852 | | ty::FnDef(..) | |
f035d41b | 853 | | ty::Error(_) |
74b04a01 | 854 | | ty::FnPtr(_) => true, |
5e7ed085 | 855 | ty::Tuple(fields) => fields.iter().all(Self::is_trivially_freeze), |
74b04a01 XL |
856 | ty::Slice(elem_ty) | ty::Array(elem_ty, _) => elem_ty.is_trivially_freeze(), |
857 | ty::Adt(..) | |
858 | | ty::Bound(..) | |
859 | | ty::Closure(..) | |
860 | | ty::Dynamic(..) | |
861 | | ty::Foreign(_) | |
862 | | ty::Generator(..) | |
863 | | ty::GeneratorWitness(_) | |
864 | | ty::Infer(_) | |
865 | | ty::Opaque(..) | |
866 | | ty::Param(_) | |
867 | | ty::Placeholder(_) | |
f9f354fc | 868 | | ty::Projection(_) => false, |
74b04a01 | 869 | } |
cc61c64b XL |
870 | } |
871 | ||
cdc7bbd5 | 872 | /// Checks whether values of this type `T` implement the `Unpin` trait. |
2b03887a FG |
873 | pub fn is_unpin(self, tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> bool { |
874 | self.is_trivially_unpin() || tcx.is_unpin_raw(param_env.and(self)) | |
cdc7bbd5 XL |
875 | } |
876 | ||
877 | /// Fast path helper for testing if a type is `Unpin`. | |
878 | /// | |
879 | /// Returning true means the type is known to be `Unpin`. Returning | |
880 | /// `false` means nothing -- could be `Unpin`, might not be. | |
5099ac24 | 881 | fn is_trivially_unpin(self) -> bool { |
cdc7bbd5 XL |
882 | match self.kind() { |
883 | ty::Int(_) | |
884 | | ty::Uint(_) | |
885 | | ty::Float(_) | |
886 | | ty::Bool | |
887 | | ty::Char | |
888 | | ty::Str | |
889 | | ty::Never | |
890 | | ty::Ref(..) | |
891 | | ty::RawPtr(_) | |
892 | | ty::FnDef(..) | |
893 | | ty::Error(_) | |
894 | | ty::FnPtr(_) => true, | |
5e7ed085 | 895 | ty::Tuple(fields) => fields.iter().all(Self::is_trivially_unpin), |
cdc7bbd5 XL |
896 | ty::Slice(elem_ty) | ty::Array(elem_ty, _) => elem_ty.is_trivially_unpin(), |
897 | ty::Adt(..) | |
898 | | ty::Bound(..) | |
899 | | ty::Closure(..) | |
900 | | ty::Dynamic(..) | |
901 | | ty::Foreign(_) | |
902 | | ty::Generator(..) | |
903 | | ty::GeneratorWitness(_) | |
904 | | ty::Infer(_) | |
905 | | ty::Opaque(..) | |
906 | | ty::Param(_) | |
907 | | ty::Placeholder(_) | |
908 | | ty::Projection(_) => false, | |
909 | } | |
910 | } | |
911 | ||
cc61c64b XL |
912 | /// If `ty.needs_drop(...)` returns `true`, then `ty` is definitely |
913 | /// non-copy and *might* have a destructor attached; if it returns | |
0731742a | 914 | /// `false`, then `ty` definitely has no destructor (i.e., no drop glue). |
cc61c64b XL |
915 | /// |
916 | /// (Note that this implies that if `ty` has a destructor attached, | |
917 | /// then `needs_drop` will definitely return `true` for `ty`.) | |
e74abb32 XL |
918 | /// |
919 | /// Note that this method is used to check eligible types in unions. | |
cc61c64b | 920 | #[inline] |
5099ac24 | 921 | pub fn needs_drop(self, tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> bool { |
74b04a01 XL |
922 | // Avoid querying in simple cases. |
923 | match needs_drop_components(self, &tcx.data_layout) { | |
924 | Err(AlwaysRequiresDrop) => true, | |
925 | Ok(components) => { | |
926 | let query_ty = match *components { | |
927 | [] => return false, | |
928 | // If we've got a single component, call the query with that | |
929 | // to increase the chance that we hit the query cache. | |
930 | [component_ty] => component_ty, | |
931 | _ => self, | |
932 | }; | |
a2a8927a | 933 | |
74b04a01 XL |
934 | // This doesn't depend on regions, so try to minimize distinct |
935 | // query keys used. | |
a2a8927a XL |
936 | // If normalization fails, we just use `query_ty`. |
937 | let query_ty = | |
938 | tcx.try_normalize_erasing_regions(param_env, query_ty).unwrap_or(query_ty); | |
939 | ||
940 | tcx.needs_drop_raw(param_env.and(query_ty)) | |
74b04a01 XL |
941 | } |
942 | } | |
cc61c64b XL |
943 | } |
944 | ||
2b03887a | 945 | /// Checks if `ty` has a significant drop. |
17df50a5 XL |
946 | /// |
947 | /// Note that this method can return false even if `ty` has a destructor | |
948 | /// attached; even if that is the case then the adt has been marked with | |
949 | /// the attribute `rustc_insignificant_dtor`. | |
950 | /// | |
951 | /// Note that this method is used to check for change in drop order for | |
952 | /// 2229 drop reorder migration analysis. | |
953 | #[inline] | |
5099ac24 | 954 | pub fn has_significant_drop(self, tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> bool { |
17df50a5 XL |
955 | // Avoid querying in simple cases. |
956 | match needs_drop_components(self, &tcx.data_layout) { | |
957 | Err(AlwaysRequiresDrop) => true, | |
958 | Ok(components) => { | |
959 | let query_ty = match *components { | |
960 | [] => return false, | |
961 | // If we've got a single component, call the query with that | |
962 | // to increase the chance that we hit the query cache. | |
963 | [component_ty] => component_ty, | |
964 | _ => self, | |
965 | }; | |
136023e0 XL |
966 | |
967 | // FIXME(#86868): We should be canonicalizing, or else moving this to a method of inference | |
968 | // context, or *something* like that, but for now just avoid passing inference | |
969 | // variables to queries that can't cope with them. Instead, conservatively | |
970 | // return "true" (may change drop order). | |
971 | if query_ty.needs_infer() { | |
972 | return true; | |
973 | } | |
974 | ||
17df50a5 XL |
975 | // This doesn't depend on regions, so try to minimize distinct |
976 | // query keys used. | |
977 | let erased = tcx.normalize_erasing_regions(param_env, query_ty); | |
978 | tcx.has_significant_drop_raw(param_env.and(erased)) | |
979 | } | |
980 | } | |
981 | } | |
982 | ||
f035d41b XL |
983 | /// Returns `true` if equality for this type is both reflexive and structural. |
984 | /// | |
985 | /// Reflexive equality for a type is indicated by an `Eq` impl for that type. | |
986 | /// | |
987 | /// Primitive types (`u32`, `str`) have structural equality by definition. For composite data | |
988 | /// types, equality for the type as a whole is structural when it is the same as equality | |
989 | /// between all components (fields, array elements, etc.) of that type. For ADTs, structural | |
990 | /// equality is indicated by an implementation of `PartialStructuralEq` and `StructuralEq` for | |
991 | /// that type. | |
992 | /// | |
993 | /// This function is "shallow" because it may return `true` for a composite type whose fields | |
994 | /// are not `StructuralEq`. For example, `[T; 4]` has structural equality regardless of `T` | |
995 | /// because equality for arrays is determined by the equality of each array element. If you | |
996 | /// want to know whether a given call to `PartialEq::eq` will proceed structurally all the way | |
997 | /// down, you will need to use a type visitor. | |
998 | #[inline] | |
5099ac24 | 999 | pub fn is_structural_eq_shallow(self, tcx: TyCtxt<'tcx>) -> bool { |
1b1a35ee | 1000 | match self.kind() { |
f035d41b | 1001 | // Look for an impl of both `PartialStructuralEq` and `StructuralEq`. |
923072b8 | 1002 | ty::Adt(..) => tcx.has_structural_eq_impls(self), |
f035d41b XL |
1003 | |
1004 | // Primitive types that satisfy `Eq`. | |
923072b8 | 1005 | ty::Bool | ty::Char | ty::Int(_) | ty::Uint(_) | ty::Str | ty::Never => true, |
f035d41b XL |
1006 | |
1007 | // Composite types that satisfy `Eq` when all of their fields do. | |
1008 | // | |
1009 | // Because this function is "shallow", we return `true` for these composites regardless | |
1010 | // of the type(s) contained within. | |
923072b8 | 1011 | ty::Ref(..) | ty::Array(..) | ty::Slice(_) | ty::Tuple(..) => true, |
f035d41b XL |
1012 | |
1013 | // Raw pointers use bitwise comparison. | |
923072b8 | 1014 | ty::RawPtr(_) | ty::FnPtr(_) => true, |
f035d41b XL |
1015 | |
1016 | // Floating point numbers are not `Eq`. | |
923072b8 | 1017 | ty::Float(_) => false, |
f035d41b XL |
1018 | |
1019 | // Conservatively return `false` for all others... | |
1020 | ||
1021 | // Anonymous function types | |
923072b8 | 1022 | ty::FnDef(..) | ty::Closure(..) | ty::Dynamic(..) | ty::Generator(..) => false, |
f035d41b XL |
1023 | |
1024 | // Generic or inferred types | |
1025 | // | |
1026 | // FIXME(ecstaticmorse): Maybe we should `bug` here? This should probably only be | |
1027 | // called for known, fully-monomorphized types. | |
923072b8 FG |
1028 | ty::Projection(_) |
1029 | | ty::Opaque(..) | |
1030 | | ty::Param(_) | |
1031 | | ty::Bound(..) | |
1032 | | ty::Placeholder(_) | |
1033 | | ty::Infer(_) => false, | |
f035d41b | 1034 | |
923072b8 | 1035 | ty::Foreign(_) | ty::GeneratorWitness(..) | ty::Error(_) => false, |
f035d41b XL |
1036 | } |
1037 | } | |
1038 | ||
e1599b0c XL |
1039 | /// Peel off all reference types in this type until there are none left. |
1040 | /// | |
1041 | /// This method is idempotent, i.e. `ty.peel_refs().peel_refs() == ty.peel_refs()`. | |
1042 | /// | |
1043 | /// # Examples | |
1044 | /// | |
1045 | /// - `u8` -> `u8` | |
1046 | /// - `&'a mut u8` -> `u8` | |
1047 | /// - `&'a &'b u8` -> `u8` | |
1048 | /// - `&'a *const &'b u8 -> *const &'b u8` | |
5099ac24 | 1049 | pub fn peel_refs(self) -> Ty<'tcx> { |
e1599b0c | 1050 | let mut ty = self; |
923072b8 | 1051 | while let ty::Ref(_, inner_ty, _) = ty.kind() { |
5099ac24 | 1052 | ty = *inner_ty; |
e1599b0c XL |
1053 | } |
1054 | ty | |
1055 | } | |
136023e0 | 1056 | |
064997fb | 1057 | #[inline] |
923072b8 | 1058 | pub fn outer_exclusive_binder(self) -> ty::DebruijnIndex { |
5099ac24 | 1059 | self.0.outer_exclusive_binder |
136023e0 | 1060 | } |
e9174d1e | 1061 | } |
7cac9316 | 1062 | |
abe05a73 XL |
1063 | pub enum ExplicitSelf<'tcx> { |
1064 | ByValue, | |
1065 | ByReference(ty::Region<'tcx>, hir::Mutability), | |
ff7c6d11 | 1066 | ByRawPointer(hir::Mutability), |
abe05a73 | 1067 | ByBox, |
dfeec247 | 1068 | Other, |
abe05a73 XL |
1069 | } |
1070 | ||
1071 | impl<'tcx> ExplicitSelf<'tcx> { | |
1072 | /// Categorizes an explicit self declaration like `self: SomeType` | |
1073 | /// into either `self`, `&self`, `&mut self`, `Box<self>`, or | |
1074 | /// `Other`. | |
1075 | /// This is mainly used to require the arbitrary_self_types feature | |
1076 | /// in the case of `Other`, to improve error messages in the common cases, | |
1077 | /// and to make `Other` non-object-safe. | |
1078 | /// | |
1079 | /// Examples: | |
1080 | /// | |
04454e1e | 1081 | /// ```ignore (illustrative) |
abe05a73 XL |
1082 | /// impl<'a> Foo for &'a T { |
1083 | /// // Legal declarations: | |
1084 | /// fn method1(self: &&'a T); // ExplicitSelf::ByReference | |
1085 | /// fn method2(self: &'a T); // ExplicitSelf::ByValue | |
1086 | /// fn method3(self: Box<&'a T>); // ExplicitSelf::ByBox | |
1087 | /// fn method4(self: Rc<&'a T>); // ExplicitSelf::Other | |
1088 | /// | |
1089 | /// // Invalid cases will be caught by `check_method_receiver`: | |
1090 | /// fn method_err1(self: &'a mut T); // ExplicitSelf::Other | |
1091 | /// fn method_err2(self: &'static T) // ExplicitSelf::ByValue | |
1092 | /// fn method_err3(self: &&T) // ExplicitSelf::ByReference | |
1093 | /// } | |
1094 | /// ``` | |
1095 | /// | |
dfeec247 | 1096 | pub fn determine<P>(self_arg_ty: Ty<'tcx>, is_self_ty: P) -> ExplicitSelf<'tcx> |
abe05a73 | 1097 | where |
dfeec247 | 1098 | P: Fn(Ty<'tcx>) -> bool, |
abe05a73 XL |
1099 | { |
1100 | use self::ExplicitSelf::*; | |
1101 | ||
1b1a35ee | 1102 | match *self_arg_ty.kind() { |
abe05a73 | 1103 | _ if is_self_ty(self_arg_ty) => ByValue, |
dfeec247 XL |
1104 | ty::Ref(region, ty, mutbl) if is_self_ty(ty) => ByReference(region, mutbl), |
1105 | ty::RawPtr(ty::TypeAndMut { ty, mutbl }) if is_self_ty(ty) => ByRawPointer(mutbl), | |
1106 | ty::Adt(def, _) if def.is_box() && is_self_ty(self_arg_ty.boxed_ty()) => ByBox, | |
1107 | _ => Other, | |
abe05a73 XL |
1108 | } |
1109 | } | |
1110 | } | |
74b04a01 XL |
1111 | |
1112 | /// Returns a list of types such that the given type needs drop if and only if | |
1113 | /// *any* of the returned types need drop. Returns `Err(AlwaysRequiresDrop)` if | |
1114 | /// this type always needs drop. | |
a2a8927a | 1115 | pub fn needs_drop_components<'tcx>( |
74b04a01 XL |
1116 | ty: Ty<'tcx>, |
1117 | target_layout: &TargetDataLayout, | |
1118 | ) -> Result<SmallVec<[Ty<'tcx>; 2]>, AlwaysRequiresDrop> { | |
1b1a35ee | 1119 | match ty.kind() { |
74b04a01 XL |
1120 | ty::Infer(ty::FreshIntTy(_)) |
1121 | | ty::Infer(ty::FreshFloatTy(_)) | |
1122 | | ty::Bool | |
1123 | | ty::Int(_) | |
1124 | | ty::Uint(_) | |
1125 | | ty::Float(_) | |
1126 | | ty::Never | |
1127 | | ty::FnDef(..) | |
1128 | | ty::FnPtr(_) | |
1129 | | ty::Char | |
1130 | | ty::GeneratorWitness(..) | |
1131 | | ty::RawPtr(_) | |
1132 | | ty::Ref(..) | |
1133 | | ty::Str => Ok(SmallVec::new()), | |
1134 | ||
1135 | // Foreign types can never have destructors. | |
1136 | ty::Foreign(..) => Ok(SmallVec::new()), | |
1137 | ||
f035d41b | 1138 | ty::Dynamic(..) | ty::Error(_) => Err(AlwaysRequiresDrop), |
74b04a01 | 1139 | |
5099ac24 | 1140 | ty::Slice(ty) => needs_drop_components(*ty, target_layout), |
74b04a01 | 1141 | ty::Array(elem_ty, size) => { |
5099ac24 | 1142 | match needs_drop_components(*elem_ty, target_layout) { |
74b04a01 | 1143 | Ok(v) if v.is_empty() => Ok(v), |
923072b8 | 1144 | res => match size.kind().try_to_bits(target_layout.pointer_size) { |
74b04a01 XL |
1145 | // Arrays of size zero don't need drop, even if their element |
1146 | // type does. | |
1147 | Some(0) => Ok(SmallVec::new()), | |
1148 | Some(_) => res, | |
1149 | // We don't know which of the cases above we are in, so | |
1150 | // return the whole type and let the caller decide what to | |
1151 | // do. | |
1152 | None => Ok(smallvec![ty]), | |
1153 | }, | |
1154 | } | |
1155 | } | |
1156 | // If any field needs drop, then the whole tuple does. | |
5e7ed085 | 1157 | ty::Tuple(fields) => fields.iter().try_fold(SmallVec::new(), move |mut acc, elem| { |
74b04a01 XL |
1158 | acc.extend(needs_drop_components(elem, target_layout)?); |
1159 | Ok(acc) | |
1160 | }), | |
1161 | ||
1162 | // These require checking for `Copy` bounds or `Adt` destructors. | |
1163 | ty::Adt(..) | |
1164 | | ty::Projection(..) | |
74b04a01 XL |
1165 | | ty::Param(_) |
1166 | | ty::Bound(..) | |
1167 | | ty::Placeholder(..) | |
1168 | | ty::Opaque(..) | |
1169 | | ty::Infer(_) | |
ba9703b0 XL |
1170 | | ty::Closure(..) |
1171 | | ty::Generator(..) => Ok(smallvec![ty]), | |
74b04a01 XL |
1172 | } |
1173 | } | |
1174 | ||
5099ac24 FG |
1175 | pub fn is_trivially_const_drop<'tcx>(ty: Ty<'tcx>) -> bool { |
1176 | match *ty.kind() { | |
1177 | ty::Bool | |
1178 | | ty::Char | |
1179 | | ty::Int(_) | |
1180 | | ty::Uint(_) | |
1181 | | ty::Float(_) | |
1182 | | ty::Infer(ty::IntVar(_)) | |
1183 | | ty::Infer(ty::FloatVar(_)) | |
1184 | | ty::Str | |
1185 | | ty::RawPtr(_) | |
1186 | | ty::Ref(..) | |
1187 | | ty::FnDef(..) | |
1188 | | ty::FnPtr(_) | |
1189 | | ty::Never | |
1190 | | ty::Foreign(_) => true, | |
1191 | ||
1192 | ty::Opaque(..) | |
1193 | | ty::Dynamic(..) | |
1194 | | ty::Error(_) | |
1195 | | ty::Bound(..) | |
1196 | | ty::Param(_) | |
1197 | | ty::Placeholder(_) | |
1198 | | ty::Projection(_) | |
1199 | | ty::Infer(_) => false, | |
1200 | ||
1201 | // Not trivial because they have components, and instead of looking inside, | |
1202 | // we'll just perform trait selection. | |
1203 | ty::Closure(..) | ty::Generator(..) | ty::GeneratorWitness(_) | ty::Adt(..) => false, | |
1204 | ||
1205 | ty::Array(ty, _) | ty::Slice(ty) => is_trivially_const_drop(ty), | |
1206 | ||
5e7ed085 | 1207 | ty::Tuple(tys) => tys.iter().all(|ty| is_trivially_const_drop(ty)), |
5099ac24 FG |
1208 | } |
1209 | } | |
1210 | ||
487cf647 FG |
1211 | /// Does the equivalent of |
1212 | /// ```ignore (ilustrative) | |
1213 | /// let v = self.iter().map(|p| p.fold_with(folder)).collect::<SmallVec<[_; 8]>>(); | |
1214 | /// folder.tcx().intern_*(&v) | |
1215 | /// ``` | |
fc512014 XL |
1216 | pub fn fold_list<'tcx, F, T>( |
1217 | list: &'tcx ty::List<T>, | |
1218 | folder: &mut F, | |
1219 | intern: impl FnOnce(TyCtxt<'tcx>, &[T]) -> &'tcx ty::List<T>, | |
a2a8927a | 1220 | ) -> Result<&'tcx ty::List<T>, F::Error> |
fc512014 | 1221 | where |
a2a8927a | 1222 | F: FallibleTypeFolder<'tcx>, |
fc512014 XL |
1223 | T: TypeFoldable<'tcx> + PartialEq + Copy, |
1224 | { | |
1225 | let mut iter = list.iter(); | |
1226 | // Look for the first element that changed | |
a2a8927a XL |
1227 | match iter.by_ref().enumerate().find_map(|(i, t)| match t.try_fold_with(folder) { |
1228 | Ok(new_t) if new_t == t => None, | |
1229 | new_t => Some((i, new_t)), | |
fc512014 | 1230 | }) { |
a2a8927a XL |
1231 | Some((i, Ok(new_t))) => { |
1232 | // An element changed, prepare to intern the resulting list | |
1233 | let mut new_list = SmallVec::<[_; 8]>::with_capacity(list.len()); | |
1234 | new_list.extend_from_slice(&list[..i]); | |
1235 | new_list.push(new_t); | |
1236 | for t in iter { | |
1237 | new_list.push(t.try_fold_with(folder)?) | |
1238 | } | |
1239 | Ok(intern(folder.tcx(), &new_list)) | |
1240 | } | |
1241 | Some((_, Err(err))) => { | |
1242 | return Err(err); | |
1243 | } | |
1244 | None => Ok(list), | |
fc512014 XL |
1245 | } |
1246 | } | |
1247 | ||
3dfed10e | 1248 | #[derive(Copy, Clone, Debug, HashStable, TyEncodable, TyDecodable)] |
74b04a01 | 1249 | pub struct AlwaysRequiresDrop; |
3dfed10e | 1250 | |
487cf647 | 1251 | /// Reveals all opaque types in the given value, replacing them |
3dfed10e | 1252 | /// with their underlying types. |
487cf647 | 1253 | pub fn reveal_opaque_types_in_bounds<'tcx>( |
3dfed10e | 1254 | tcx: TyCtxt<'tcx>, |
923072b8 FG |
1255 | val: &'tcx ty::List<ty::Predicate<'tcx>>, |
1256 | ) -> &'tcx ty::List<ty::Predicate<'tcx>> { | |
3dfed10e XL |
1257 | let mut visitor = OpaqueTypeExpander { |
1258 | seen_opaque_tys: FxHashSet::default(), | |
1259 | expanded_cache: FxHashMap::default(), | |
1260 | primary_def_id: None, | |
1261 | found_recursion: false, | |
94222f64 | 1262 | found_any_recursion: false, |
3dfed10e XL |
1263 | check_recursion: false, |
1264 | tcx, | |
1265 | }; | |
1266 | val.fold_with(&mut visitor) | |
1267 | } | |
1268 | ||
5e7ed085 FG |
1269 | /// Determines whether an item is annotated with `doc(hidden)`. |
1270 | pub fn is_doc_hidden(tcx: TyCtxt<'_>, def_id: DefId) -> bool { | |
04454e1e FG |
1271 | tcx.get_attrs(def_id, sym::doc) |
1272 | .filter_map(|attr| attr.meta_item_list()) | |
5e7ed085 FG |
1273 | .any(|items| items.iter().any(|item| item.has_name(sym::hidden))) |
1274 | } | |
1275 | ||
2b03887a FG |
1276 | /// Determines whether an item is annotated with `doc(notable_trait)`. |
1277 | pub fn is_doc_notable_trait(tcx: TyCtxt<'_>, def_id: DefId) -> bool { | |
1278 | tcx.get_attrs(def_id, sym::doc) | |
1279 | .filter_map(|attr| attr.meta_item_list()) | |
1280 | .any(|items| items.iter().any(|item| item.has_name(sym::notable_trait))) | |
1281 | } | |
1282 | ||
923072b8 FG |
1283 | /// Determines whether an item is an intrinsic by Abi. |
1284 | pub fn is_intrinsic(tcx: TyCtxt<'_>, def_id: DefId) -> bool { | |
1285 | matches!(tcx.fn_sig(def_id).abi(), Abi::RustIntrinsic | Abi::PlatformIntrinsic) | |
1286 | } | |
1287 | ||
3dfed10e | 1288 | pub fn provide(providers: &mut ty::query::Providers) { |
2b03887a | 1289 | *providers = ty::query::Providers { |
487cf647 | 1290 | reveal_opaque_types_in_bounds, |
2b03887a FG |
1291 | is_doc_hidden, |
1292 | is_doc_notable_trait, | |
1293 | is_intrinsic, | |
1294 | ..*providers | |
1295 | } | |
3dfed10e | 1296 | } |