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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; |
9c376795 | 4 | use crate::mir; |
353b0b11 | 5 | use crate::ty::fast_reject::TreatProjections; |
ba9703b0 | 6 | use crate::ty::layout::IntegerExt; |
5099ac24 | 7 | use crate::ty::{ |
353b0b11 FG |
8 | self, FallibleTypeFolder, ToPredicate, Ty, TyCtxt, TypeFoldable, TypeFolder, TypeSuperFoldable, |
9 | TypeVisitableExt, | |
5099ac24 | 10 | }; |
2b03887a | 11 | use crate::ty::{GenericArgKind, SubstsRef}; |
dfeec247 | 12 | use rustc_apfloat::Float as _; |
0731742a | 13 | use rustc_data_structures::fx::{FxHashMap, FxHashSet}; |
dfeec247 | 14 | use rustc_data_structures::stable_hasher::{HashStable, StableHasher}; |
5e7ed085 | 15 | use rustc_errors::ErrorGuaranteed; |
dfeec247 | 16 | use rustc_hir as hir; |
5099ac24 | 17 | use rustc_hir::def::{CtorOf, DefKind, Res}; |
353b0b11 | 18 | use rustc_hir::def_id::{DefId, LocalDefId}; |
923072b8 | 19 | use rustc_index::bit_set::GrowableBitSet; |
9c376795 | 20 | use rustc_index::vec::{Idx, IndexVec}; |
532ac7d7 | 21 | use rustc_macros::HashStable; |
353b0b11 FG |
22 | use rustc_session::Limit; |
23 | use rustc_span::sym; | |
487cf647 | 24 | use rustc_target::abi::{Integer, IntegerType, Size, TargetDataLayout}; |
923072b8 | 25 | use rustc_target::spec::abi::Abi; |
74b04a01 | 26 | use smallvec::SmallVec; |
cdc7bbd5 | 27 | use std::{fmt, iter}; |
e9174d1e | 28 | |
0531ce1d XL |
29 | #[derive(Copy, Clone, Debug)] |
30 | pub struct Discr<'tcx> { | |
9fa01778 | 31 | /// Bit representation of the discriminant (e.g., `-128i8` is `0xFF_u128`). |
0531ce1d | 32 | pub val: u128, |
dfeec247 | 33 | pub ty: Ty<'tcx>, |
0531ce1d | 34 | } |
8bb4bdeb | 35 | |
923072b8 FG |
36 | /// Used as an input to [`TyCtxt::uses_unique_generic_params`]. |
37 | #[derive(Copy, Clone, Debug, PartialEq, Eq)] | |
38 | pub enum IgnoreRegions { | |
39 | Yes, | |
40 | No, | |
41 | } | |
42 | ||
43 | #[derive(Copy, Clone, Debug)] | |
44 | pub enum NotUniqueParam<'tcx> { | |
45 | DuplicateParam(ty::GenericArg<'tcx>), | |
46 | NotParam(ty::GenericArg<'tcx>), | |
47 | } | |
48 | ||
0531ce1d | 49 | impl<'tcx> fmt::Display for Discr<'tcx> { |
0bf4aa26 | 50 | fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result { |
1b1a35ee | 51 | match *self.ty.kind() { |
b7449926 | 52 | ty::Int(ity) => { |
5869c6ff | 53 | let size = ty::tls::with(|tcx| Integer::from_int_ty(&tcx, ity).size()); |
532ac7d7 | 54 | let x = self.val; |
0531ce1d | 55 | // sign extend the raw representation to be an i128 |
29967ef6 | 56 | let x = size.sign_extend(x) as i128; |
0531ce1d | 57 | write!(fmt, "{}", x) |
dfeec247 | 58 | } |
0531ce1d XL |
59 | _ => write!(fmt, "{}", self.val), |
60 | } | |
61 | } | |
cc61c64b | 62 | } |
8bb4bdeb | 63 | |
0531ce1d | 64 | impl<'tcx> Discr<'tcx> { |
9fa01778 | 65 | /// Adds `1` to the value and wraps around if the maximum for the type is reached. |
dc9dc135 | 66 | pub fn wrap_incr(self, tcx: TyCtxt<'tcx>) -> Self { |
0531ce1d XL |
67 | self.checked_add(tcx, 1).0 |
68 | } | |
dc9dc135 | 69 | pub fn checked_add(self, tcx: TyCtxt<'tcx>, n: u128) -> (Self, bool) { |
353b0b11 | 70 | let (size, signed) = self.ty.int_size_and_signed(tcx); |
dfeec247 | 71 | let (val, oflo) = if signed { |
c295e0f8 XL |
72 | let min = size.signed_int_min(); |
73 | let max = size.signed_int_max(); | |
29967ef6 | 74 | let val = size.sign_extend(self.val) as i128; |
74b04a01 | 75 | assert!(n < (i128::MAX as u128)); |
0531ce1d XL |
76 | let n = n as i128; |
77 | let oflo = val > max - n; | |
dfeec247 | 78 | let val = if oflo { min + (n - (max - val) - 1) } else { val + n }; |
0531ce1d XL |
79 | // zero the upper bits |
80 | let val = val as u128; | |
29967ef6 | 81 | let val = size.truncate(val); |
dfeec247 | 82 | (val, oflo) |
0531ce1d | 83 | } else { |
c295e0f8 | 84 | let max = size.unsigned_int_max(); |
0531ce1d XL |
85 | let val = self.val; |
86 | let oflo = val > max - n; | |
dfeec247 XL |
87 | let val = if oflo { n - (max - val) - 1 } else { val + n }; |
88 | (val, oflo) | |
89 | }; | |
90 | (Self { val, ty: self.ty }, oflo) | |
8bb4bdeb | 91 | } |
e9174d1e SL |
92 | } |
93 | ||
0531ce1d | 94 | pub trait IntTypeExt { |
dc9dc135 XL |
95 | fn to_ty<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Ty<'tcx>; |
96 | fn disr_incr<'tcx>(&self, tcx: TyCtxt<'tcx>, val: Option<Discr<'tcx>>) -> Option<Discr<'tcx>>; | |
97 | fn initial_discriminant<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Discr<'tcx>; | |
0531ce1d XL |
98 | } |
99 | ||
487cf647 | 100 | impl IntTypeExt for IntegerType { |
dc9dc135 | 101 | fn to_ty<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> { |
487cf647 FG |
102 | match self { |
103 | IntegerType::Pointer(true) => tcx.types.isize, | |
104 | IntegerType::Pointer(false) => tcx.types.usize, | |
105 | IntegerType::Fixed(i, s) => i.to_ty(tcx, *s), | |
e9174d1e SL |
106 | } |
107 | } | |
108 | ||
dc9dc135 | 109 | fn initial_discriminant<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Discr<'tcx> { |
dfeec247 | 110 | Discr { val: 0, ty: self.to_ty(tcx) } |
e9174d1e SL |
111 | } |
112 | ||
dc9dc135 | 113 | fn disr_incr<'tcx>(&self, tcx: TyCtxt<'tcx>, val: Option<Discr<'tcx>>) -> Option<Discr<'tcx>> { |
a7813a04 | 114 | if let Some(val) = val { |
0531ce1d XL |
115 | assert_eq!(self.to_ty(tcx), val.ty); |
116 | let (new, oflo) = val.checked_add(tcx, 1); | |
dfeec247 | 117 | if oflo { None } else { Some(new) } |
a7813a04 XL |
118 | } else { |
119 | Some(self.initial_discriminant(tcx)) | |
120 | } | |
e9174d1e SL |
121 | } |
122 | } | |
123 | ||
dc9dc135 | 124 | impl<'tcx> TyCtxt<'tcx> { |
cc61c64b XL |
125 | /// Creates a hash of the type `Ty` which will be the same no matter what crate |
126 | /// context it's calculated within. This is used by the `type_id` intrinsic. | |
127 | pub fn type_id_hash(self, ty: Ty<'tcx>) -> u64 { | |
3b2f2976 XL |
128 | // We want the type_id be independent of the types free regions, so we |
129 | // erase them. The erase_regions() call will also anonymize bound | |
130 | // regions, which is desirable too. | |
fc512014 | 131 | let ty = self.erase_regions(ty); |
3b2f2976 | 132 | |
064997fb FG |
133 | self.with_stable_hashing_context(|mut hcx| { |
134 | let mut hasher = StableHasher::new(); | |
135 | hcx.while_hashing_spans(false, |hcx| ty.hash_stable(hcx, &mut hasher)); | |
136 | hasher.finish() | |
137 | }) | |
cc61c64b | 138 | } |
cc61c64b | 139 | |
5099ac24 FG |
140 | pub fn res_generics_def_id(self, res: Res) -> Option<DefId> { |
141 | match res { | |
142 | Res::Def(DefKind::Ctor(CtorOf::Variant, _), def_id) => { | |
04454e1e | 143 | Some(self.parent(self.parent(def_id))) |
5099ac24 FG |
144 | } |
145 | Res::Def(DefKind::Variant | DefKind::Ctor(CtorOf::Struct, _), def_id) => { | |
04454e1e | 146 | Some(self.parent(def_id)) |
5099ac24 FG |
147 | } |
148 | // Other `DefKind`s don't have generics and would ICE when calling | |
149 | // `generics_of`. | |
150 | Res::Def( | |
151 | DefKind::Struct | |
152 | | DefKind::Union | |
153 | | DefKind::Enum | |
154 | | DefKind::Trait | |
155 | | DefKind::OpaqueTy | |
156 | | DefKind::TyAlias | |
157 | | DefKind::ForeignTy | |
158 | | DefKind::TraitAlias | |
159 | | DefKind::AssocTy | |
160 | | DefKind::Fn | |
161 | | DefKind::AssocFn | |
162 | | DefKind::AssocConst | |
9ffffee4 | 163 | | DefKind::Impl { .. }, |
5099ac24 FG |
164 | def_id, |
165 | ) => Some(def_id), | |
166 | Res::Err => None, | |
167 | _ => None, | |
168 | } | |
169 | } | |
170 | ||
5bcae85e | 171 | pub fn has_error_field(self, ty: Ty<'tcx>) -> bool { |
1b1a35ee | 172 | if let ty::Adt(def, substs) = *ty.kind() { |
0bf4aa26 XL |
173 | for field in def.all_fields() { |
174 | let field_ty = field.ty(self, substs); | |
923072b8 | 175 | if let ty::Error(_) = field_ty.kind() { |
0bf4aa26 | 176 | return true; |
5bcae85e SL |
177 | } |
178 | } | |
5bcae85e SL |
179 | } |
180 | false | |
181 | } | |
182 | ||
416331ca XL |
183 | /// Attempts to returns the deeply last field of nested structures, but |
184 | /// does not apply any normalization in its search. Returns the same type | |
185 | /// if input `ty` is not a structure at all. | |
dfeec247 | 186 | pub fn struct_tail_without_normalization(self, ty: Ty<'tcx>) -> Ty<'tcx> { |
416331ca | 187 | let tcx = self; |
04454e1e | 188 | tcx.struct_tail_with_normalize(ty, |ty| ty, || {}) |
416331ca XL |
189 | } |
190 | ||
191 | /// Returns the deeply last field of nested structures, or the same type if | |
192 | /// not a structure at all. Corresponds to the only possible unsized field, | |
193 | /// and its type can be used to determine unsizing strategy. | |
194 | /// | |
195 | /// Should only be called if `ty` has no inference variables and does not | |
196 | /// need its lifetimes preserved (e.g. as part of codegen); otherwise | |
197 | /// normalization attempt may cause compiler bugs. | |
dfeec247 XL |
198 | pub fn struct_tail_erasing_lifetimes( |
199 | self, | |
200 | ty: Ty<'tcx>, | |
201 | param_env: ty::ParamEnv<'tcx>, | |
202 | ) -> Ty<'tcx> { | |
416331ca | 203 | let tcx = self; |
04454e1e | 204 | tcx.struct_tail_with_normalize(ty, |ty| tcx.normalize_erasing_regions(param_env, ty), || {}) |
416331ca XL |
205 | } |
206 | ||
207 | /// Returns the deeply last field of nested structures, or the same type if | |
208 | /// not a structure at all. Corresponds to the only possible unsized field, | |
209 | /// and its type can be used to determine unsizing strategy. | |
210 | /// | |
211 | /// This is parameterized over the normalization strategy (i.e. how to | |
212 | /// handle `<T as Trait>::Assoc` and `impl Trait`); pass the identity | |
213 | /// function to indicate no normalization should take place. | |
214 | /// | |
215 | /// See also `struct_tail_erasing_lifetimes`, which is suitable for use | |
216 | /// during codegen. | |
dfeec247 XL |
217 | pub fn struct_tail_with_normalize( |
218 | self, | |
219 | mut ty: Ty<'tcx>, | |
5099ac24 | 220 | mut normalize: impl FnMut(Ty<'tcx>) -> Ty<'tcx>, |
04454e1e FG |
221 | // This is currently used to allow us to walk a ValTree |
222 | // in lockstep with the type in order to get the ValTree branch that | |
223 | // corresponds to an unsized field. | |
224 | mut f: impl FnMut() -> (), | |
dfeec247 | 225 | ) -> Ty<'tcx> { |
136023e0 | 226 | let recursion_limit = self.recursion_limit(); |
fc512014 | 227 | for iteration in 0.. { |
136023e0 | 228 | if !recursion_limit.value_within_limit(iteration) { |
353b0b11 FG |
229 | let suggested_limit = match recursion_limit { |
230 | Limit(0) => Limit(2), | |
231 | limit => limit * 2, | |
232 | }; | |
233 | let reported = | |
234 | self.sess.emit_err(crate::error::RecursionLimitReached { ty, suggested_limit }); | |
235 | return self.ty_error(reported); | |
fc512014 | 236 | } |
1b1a35ee | 237 | match *ty.kind() { |
b7449926 | 238 | ty::Adt(def, substs) => { |
7cac9316 XL |
239 | if !def.is_struct() { |
240 | break; | |
241 | } | |
353b0b11 | 242 | match def.non_enum_variant().fields.raw.last() { |
04454e1e FG |
243 | Some(field) => { |
244 | f(); | |
245 | ty = field.ty(self, substs); | |
246 | } | |
7cac9316 XL |
247 | None => break, |
248 | } | |
249 | } | |
250 | ||
94222f64 | 251 | ty::Tuple(tys) if let Some((&last_ty, _)) = tys.split_last() => { |
04454e1e | 252 | f(); |
5e7ed085 | 253 | ty = last_ty; |
7cac9316 XL |
254 | } |
255 | ||
94222f64 XL |
256 | ty::Tuple(_) => break, |
257 | ||
9c376795 | 258 | ty::Alias(..) => { |
416331ca XL |
259 | let normalized = normalize(ty); |
260 | if ty == normalized { | |
261 | return ty; | |
262 | } else { | |
263 | ty = normalized; | |
264 | } | |
265 | } | |
266 | ||
7cac9316 XL |
267 | _ => { |
268 | break; | |
269 | } | |
e9174d1e SL |
270 | } |
271 | } | |
272 | ty | |
273 | } | |
274 | ||
60c5eb7d | 275 | /// Same as applying `struct_tail` on `source` and `target`, but only |
e9174d1e SL |
276 | /// keeps going as long as the two types are instances of the same |
277 | /// structure definitions. | |
a1dfa0c6 | 278 | /// For `(Foo<Foo<T>>, Foo<dyn Trait>)`, the result will be `(Foo<T>, Trait)`, |
e9174d1e | 279 | /// whereas struct_tail produces `T`, and `Trait`, respectively. |
416331ca XL |
280 | /// |
281 | /// Should only be called if the types have no inference variables and do | |
60c5eb7d | 282 | /// not need their lifetimes preserved (e.g., as part of codegen); otherwise, |
416331ca | 283 | /// normalization attempt may cause compiler bugs. |
dfeec247 XL |
284 | pub fn struct_lockstep_tails_erasing_lifetimes( |
285 | self, | |
286 | source: Ty<'tcx>, | |
287 | target: Ty<'tcx>, | |
288 | param_env: ty::ParamEnv<'tcx>, | |
289 | ) -> (Ty<'tcx>, Ty<'tcx>) { | |
416331ca | 290 | let tcx = self; |
dfeec247 XL |
291 | tcx.struct_lockstep_tails_with_normalize(source, target, |ty| { |
292 | tcx.normalize_erasing_regions(param_env, ty) | |
293 | }) | |
416331ca XL |
294 | } |
295 | ||
60c5eb7d | 296 | /// Same as applying `struct_tail` on `source` and `target`, but only |
416331ca XL |
297 | /// keeps going as long as the two types are instances of the same |
298 | /// structure definitions. | |
299 | /// For `(Foo<Foo<T>>, Foo<dyn Trait>)`, the result will be `(Foo<T>, Trait)`, | |
300 | /// whereas struct_tail produces `T`, and `Trait`, respectively. | |
301 | /// | |
302 | /// See also `struct_lockstep_tails_erasing_lifetimes`, which is suitable for use | |
303 | /// during codegen. | |
dfeec247 XL |
304 | pub fn struct_lockstep_tails_with_normalize( |
305 | self, | |
306 | source: Ty<'tcx>, | |
307 | target: Ty<'tcx>, | |
308 | normalize: impl Fn(Ty<'tcx>) -> Ty<'tcx>, | |
309 | ) -> (Ty<'tcx>, Ty<'tcx>) { | |
e9174d1e | 310 | let (mut a, mut b) = (source, target); |
041b39d2 | 311 | loop { |
1b1a35ee | 312 | match (&a.kind(), &b.kind()) { |
923072b8 | 313 | (&ty::Adt(a_def, a_substs), &ty::Adt(b_def, b_substs)) |
dfeec247 XL |
314 | if a_def == b_def && a_def.is_struct() => |
315 | { | |
353b0b11 | 316 | if let Some(f) = a_def.non_enum_variant().fields.raw.last() { |
041b39d2 XL |
317 | a = f.ty(self, a_substs); |
318 | b = f.ty(self, b_substs); | |
319 | } else { | |
320 | break; | |
321 | } | |
dfeec247 | 322 | } |
923072b8 | 323 | (&ty::Tuple(a_tys), &ty::Tuple(b_tys)) if a_tys.len() == b_tys.len() => { |
5e7ed085 FG |
324 | if let Some(&a_last) = a_tys.last() { |
325 | a = a_last; | |
326 | b = *b_tys.last().unwrap(); | |
041b39d2 XL |
327 | } else { |
328 | break; | |
329 | } | |
dfeec247 | 330 | } |
9c376795 | 331 | (ty::Alias(..), _) | (_, ty::Alias(..)) => { |
416331ca XL |
332 | // If either side is a projection, attempt to |
333 | // progress via normalization. (Should be safe to | |
334 | // apply to both sides as normalization is | |
335 | // idempotent.) | |
336 | let a_norm = normalize(a); | |
337 | let b_norm = normalize(b); | |
338 | if a == a_norm && b == b_norm { | |
339 | break; | |
340 | } else { | |
341 | a = a_norm; | |
342 | b = b_norm; | |
343 | } | |
344 | } | |
345 | ||
cc61c64b | 346 | _ => break, |
e9174d1e SL |
347 | } |
348 | } | |
349 | (a, b) | |
350 | } | |
351 | ||
8bb4bdeb XL |
352 | /// Calculate the destructor of a given type. |
353 | pub fn calculate_dtor( | |
354 | self, | |
355 | adt_did: DefId, | |
5e7ed085 | 356 | validate: impl Fn(Self, DefId) -> Result<(), ErrorGuaranteed>, |
8bb4bdeb | 357 | ) -> Option<ty::Destructor> { |
ba9703b0 | 358 | let drop_trait = self.lang_items().drop_trait()?; |
9fa01778 | 359 | self.ensure().coherent_trait(drop_trait); |
8bb4bdeb | 360 | |
9ffffee4 | 361 | let ty = self.type_of(adt_did).subst_identity(); |
353b0b11 FG |
362 | let (did, constness) = self.find_map_relevant_impl( |
363 | drop_trait, | |
364 | ty, | |
365 | // FIXME: This could also be some other mode, like "unexpected" | |
366 | TreatProjections::ForLookup, | |
367 | |impl_did| { | |
368 | if let Some(item_id) = self.associated_item_def_ids(impl_did).first() { | |
369 | if validate(self, impl_did).is_ok() { | |
370 | return Some((*item_id, self.constness(impl_did))); | |
371 | } | |
8bb4bdeb | 372 | } |
353b0b11 FG |
373 | None |
374 | }, | |
375 | )?; | |
8bb4bdeb | 376 | |
c295e0f8 | 377 | Some(ty::Destructor { did, constness }) |
cc61c64b XL |
378 | } |
379 | ||
9fa01778 | 380 | /// Returns the set of types that are required to be alive in |
cc61c64b XL |
381 | /// order to run the destructor of `def` (see RFCs 769 and |
382 | /// 1238). | |
383 | /// | |
384 | /// Note that this returns only the constraints for the | |
385 | /// destructor of `def` itself. For the destructors of the | |
386 | /// contents, you need `adt_dtorck_constraint`. | |
5e7ed085 | 387 | pub fn destructor_constraints(self, def: ty::AdtDef<'tcx>) -> Vec<ty::subst::GenericArg<'tcx>> { |
cc61c64b XL |
388 | let dtor = match def.destructor(self) { |
389 | None => { | |
5e7ed085 | 390 | debug!("destructor_constraints({:?}) - no dtor", def.did()); |
dfeec247 | 391 | return vec![]; |
cc61c64b | 392 | } |
dfeec247 | 393 | Some(dtor) => dtor.did, |
e9174d1e | 394 | }; |
b039eaaf | 395 | |
064997fb | 396 | let impl_def_id = self.parent(dtor); |
7cac9316 | 397 | let impl_generics = self.generics_of(impl_def_id); |
cc61c64b XL |
398 | |
399 | // We have a destructor - all the parameters that are not | |
400 | // pure_wrt_drop (i.e, don't have a #[may_dangle] attribute) | |
401 | // must be live. | |
402 | ||
403 | // We need to return the list of parameters from the ADTs | |
404 | // generics/substs that correspond to impure parameters on the | |
405 | // impl's generics. This is a bit ugly, but conceptually simple: | |
406 | // | |
407 | // Suppose our ADT looks like the following | |
408 | // | |
409 | // struct S<X, Y, Z>(X, Y, Z); | |
410 | // | |
411 | // and the impl is | |
412 | // | |
413 | // impl<#[may_dangle] P0, P1, P2> Drop for S<P1, P2, P0> | |
414 | // | |
415 | // We want to return the parameters (X, Y). For that, we match | |
416 | // up the item-substs <X, Y, Z> with the substs on the impl ADT, | |
417 | // <P1, P2, P0>, and then look up which of the impl substs refer to | |
418 | // parameters marked as pure. | |
419 | ||
9ffffee4 | 420 | let impl_substs = match *self.type_of(impl_def_id).subst_identity().kind() { |
b7449926 | 421 | ty::Adt(def_, substs) if def_ == def => substs, |
dfeec247 | 422 | _ => bug!(), |
cc61c64b XL |
423 | }; |
424 | ||
9ffffee4 | 425 | let item_substs = match *self.type_of(def.did()).subst_identity().kind() { |
b7449926 | 426 | ty::Adt(def_, substs) if def_ == def => substs, |
dfeec247 | 427 | _ => bug!(), |
cc61c64b XL |
428 | }; |
429 | ||
cdc7bbd5 | 430 | let result = iter::zip(item_substs, impl_substs) |
f9f354fc | 431 | .filter(|&(_, k)| { |
0531ce1d | 432 | match k.unpack() { |
04454e1e | 433 | GenericArgKind::Lifetime(region) => match region.kind() { |
923072b8 | 434 | ty::ReEarlyBound(ref ebr) => { |
04454e1e FG |
435 | !impl_generics.region_param(ebr, self).pure_wrt_drop |
436 | } | |
437 | // Error: not a region param | |
438 | _ => false, | |
439 | }, | |
440 | GenericArgKind::Type(ty) => match ty.kind() { | |
441 | ty::Param(ref pt) => !impl_generics.type_param(pt, self).pure_wrt_drop, | |
442 | // Error: not a type param | |
443 | _ => false, | |
444 | }, | |
923072b8 | 445 | GenericArgKind::Const(ct) => match ct.kind() { |
04454e1e FG |
446 | ty::ConstKind::Param(ref pc) => { |
447 | !impl_generics.const_param(pc, self).pure_wrt_drop | |
448 | } | |
449 | // Error: not a const param | |
450 | _ => false, | |
451 | }, | |
cc61c64b | 452 | } |
0bf4aa26 | 453 | }) |
f9f354fc | 454 | .map(|(item_param, _)| item_param) |
0bf4aa26 | 455 | .collect(); |
5e7ed085 | 456 | debug!("destructor_constraint({:?}) = {:?}", def.did(), result); |
cc61c64b | 457 | result |
b039eaaf | 458 | } |
9e0c209e | 459 | |
923072b8 FG |
460 | /// Checks whether each generic argument is simply a unique generic parameter. |
461 | pub fn uses_unique_generic_params( | |
462 | self, | |
463 | substs: SubstsRef<'tcx>, | |
464 | ignore_regions: IgnoreRegions, | |
465 | ) -> Result<(), NotUniqueParam<'tcx>> { | |
466 | let mut seen = GrowableBitSet::default(); | |
467 | for arg in substs { | |
468 | match arg.unpack() { | |
469 | GenericArgKind::Lifetime(lt) => { | |
470 | if ignore_regions == IgnoreRegions::No { | |
471 | let ty::ReEarlyBound(p) = lt.kind() else { | |
472 | return Err(NotUniqueParam::NotParam(lt.into())) | |
473 | }; | |
474 | if !seen.insert(p.index) { | |
475 | return Err(NotUniqueParam::DuplicateParam(lt.into())); | |
476 | } | |
477 | } | |
478 | } | |
479 | GenericArgKind::Type(t) => match t.kind() { | |
480 | ty::Param(p) => { | |
481 | if !seen.insert(p.index) { | |
482 | return Err(NotUniqueParam::DuplicateParam(t.into())); | |
483 | } | |
484 | } | |
485 | _ => return Err(NotUniqueParam::NotParam(t.into())), | |
486 | }, | |
487 | GenericArgKind::Const(c) => match c.kind() { | |
488 | ty::ConstKind::Param(p) => { | |
489 | if !seen.insert(p.index) { | |
490 | return Err(NotUniqueParam::DuplicateParam(c.into())); | |
491 | } | |
492 | } | |
493 | _ => return Err(NotUniqueParam::NotParam(c.into())), | |
494 | }, | |
495 | } | |
496 | } | |
497 | ||
498 | Ok(()) | |
499 | } | |
500 | ||
9fa01778 XL |
501 | /// Returns `true` if `def_id` refers to a closure (e.g., `|x| x * 2`). Note |
502 | /// that closures have a `DefId`, but the closure *expression* also | |
8faf50e0 XL |
503 | /// has a `HirId` that is located within the context where the |
504 | /// closure appears (and, sadly, a corresponding `NodeId`, since | |
505 | /// those are not yet phased out). The parent of the closure's | |
9fa01778 | 506 | /// `DefId` will also be the context where it appears. |
abe05a73 | 507 | pub fn is_closure(self, def_id: DefId) -> bool { |
f9f354fc | 508 | matches!(self.def_kind(def_id), DefKind::Closure | DefKind::Generator) |
abe05a73 XL |
509 | } |
510 | ||
3c0e092e XL |
511 | /// Returns `true` if `def_id` refers to a definition that does not have its own |
512 | /// type-checking context, i.e. closure, generator or inline const. | |
513 | pub fn is_typeck_child(self, def_id: DefId) -> bool { | |
514 | matches!( | |
515 | self.def_kind(def_id), | |
516 | DefKind::Closure | DefKind::Generator | DefKind::InlineConst | |
517 | ) | |
518 | } | |
519 | ||
9fa01778 | 520 | /// Returns `true` if `def_id` refers to a trait (i.e., `trait Foo { ... }`). |
8faf50e0 | 521 | pub fn is_trait(self, def_id: DefId) -> bool { |
f9f354fc | 522 | self.def_kind(def_id) == DefKind::Trait |
8faf50e0 XL |
523 | } |
524 | ||
9fa01778 XL |
525 | /// Returns `true` if `def_id` refers to a trait alias (i.e., `trait Foo = ...;`), |
526 | /// and `false` otherwise. | |
527 | pub fn is_trait_alias(self, def_id: DefId) -> bool { | |
f9f354fc | 528 | self.def_kind(def_id) == DefKind::TraitAlias |
9fa01778 XL |
529 | } |
530 | ||
531 | /// Returns `true` if this `DefId` refers to the implicit constructor for | |
532 | /// a tuple struct like `struct Foo(u32)`, and `false` otherwise. | |
532ac7d7 | 533 | pub fn is_constructor(self, def_id: DefId) -> bool { |
f9f354fc | 534 | matches!(self.def_kind(def_id), DefKind::Ctor(..)) |
8faf50e0 XL |
535 | } |
536 | ||
3c0e092e | 537 | /// Given the `DefId`, returns the `DefId` of the innermost item that |
5e7ed085 | 538 | /// has its own type-checking context or "inference environment". |
3c0e092e XL |
539 | /// |
540 | /// For example, a closure has its own `DefId`, but it is type-checked | |
541 | /// with the containing item. Similarly, an inline const block has its | |
542 | /// own `DefId` but it is type-checked together with the containing item. | |
543 | /// | |
544 | /// Therefore, when we fetch the | |
3dfed10e XL |
545 | /// `typeck` the closure, for example, we really wind up |
546 | /// fetching the `typeck` the enclosing fn item. | |
3c0e092e | 547 | pub fn typeck_root_def_id(self, def_id: DefId) -> DefId { |
476ff2be | 548 | let mut def_id = def_id; |
3c0e092e | 549 | while self.is_typeck_child(def_id) { |
04454e1e | 550 | def_id = self.parent(def_id); |
476ff2be SL |
551 | } |
552 | def_id | |
9e0c209e | 553 | } |
cc61c64b | 554 | |
9fa01778 | 555 | /// Given the `DefId` and substs a closure, creates the type of |
ff7c6d11 XL |
556 | /// `self` argument that the closure expects. For example, for a |
557 | /// `Fn` closure, this would return a reference type `&T` where | |
9fa01778 | 558 | /// `T = closure_ty`. |
ff7c6d11 XL |
559 | /// |
560 | /// Returns `None` if this closure's kind has not yet been inferred. | |
561 | /// This should only be possible during type checking. | |
562 | /// | |
563 | /// Note that the return value is a late-bound region and hence | |
564 | /// wrapped in a binder. | |
dfeec247 XL |
565 | pub fn closure_env_ty( |
566 | self, | |
567 | closure_def_id: DefId, | |
568 | closure_substs: SubstsRef<'tcx>, | |
9ffffee4 | 569 | env_region: ty::Region<'tcx>, |
cdc7bbd5 | 570 | ) -> Option<Ty<'tcx>> { |
ff7c6d11 | 571 | let closure_ty = self.mk_closure(closure_def_id, closure_substs); |
ba9703b0 | 572 | let closure_kind_ty = closure_substs.as_closure().kind_ty(); |
ff7c6d11 XL |
573 | let closure_kind = closure_kind_ty.to_opt_closure_kind()?; |
574 | let env_ty = match closure_kind { | |
9ffffee4 FG |
575 | ty::ClosureKind::Fn => self.mk_imm_ref(env_region, closure_ty), |
576 | ty::ClosureKind::FnMut => self.mk_mut_ref(env_region, closure_ty), | |
ff7c6d11 XL |
577 | ty::ClosureKind::FnOnce => closure_ty, |
578 | }; | |
cdc7bbd5 | 579 | Some(env_ty) |
ff7c6d11 XL |
580 | } |
581 | ||
48663c56 | 582 | /// Returns `true` if the node pointed to by `def_id` is a `static` item. |
5e7ed085 | 583 | #[inline] |
1b1a35ee | 584 | pub fn is_static(self, def_id: DefId) -> bool { |
5e7ed085 FG |
585 | matches!(self.def_kind(def_id), DefKind::Static(_)) |
586 | } | |
587 | ||
588 | #[inline] | |
589 | pub fn static_mutability(self, def_id: DefId) -> Option<hir::Mutability> { | |
590 | if let DefKind::Static(mt) = self.def_kind(def_id) { Some(mt) } else { None } | |
48663c56 XL |
591 | } |
592 | ||
f9f354fc | 593 | /// Returns `true` if this is a `static` item with the `#[thread_local]` attribute. |
1b1a35ee | 594 | pub fn is_thread_local_static(self, def_id: DefId) -> bool { |
f9f354fc XL |
595 | self.codegen_fn_attrs(def_id).flags.contains(CodegenFnAttrFlags::THREAD_LOCAL) |
596 | } | |
597 | ||
48663c56 | 598 | /// Returns `true` if the node pointed to by `def_id` is a mutable `static` item. |
5e7ed085 | 599 | #[inline] |
1b1a35ee | 600 | pub fn is_mutable_static(self, def_id: DefId) -> bool { |
dfeec247 | 601 | self.static_mutability(def_id) == Some(hir::Mutability::Mut) |
60c5eb7d XL |
602 | } |
603 | ||
353b0b11 FG |
604 | /// Returns `true` if the item pointed to by `def_id` is a thread local which needs a |
605 | /// thread local shim generated. | |
606 | #[inline] | |
607 | pub fn needs_thread_local_shim(self, def_id: DefId) -> bool { | |
608 | !self.sess.target.dll_tls_export | |
609 | && self.is_thread_local_static(def_id) | |
610 | && !self.is_foreign_item(def_id) | |
611 | } | |
612 | ||
613 | /// Returns the type a reference to the thread local takes in MIR. | |
614 | pub fn thread_local_ptr_ty(self, def_id: DefId) -> Ty<'tcx> { | |
615 | let static_ty = self.type_of(def_id).subst_identity(); | |
616 | if self.is_mutable_static(def_id) { | |
617 | self.mk_mut_ptr(static_ty) | |
618 | } else if self.is_foreign_item(def_id) { | |
619 | self.mk_imm_ptr(static_ty) | |
620 | } else { | |
621 | // FIXME: These things don't *really* have 'static lifetime. | |
622 | self.mk_imm_ref(self.lifetimes.re_static, static_ty) | |
623 | } | |
624 | } | |
625 | ||
60c5eb7d | 626 | /// Get the type of the pointer to the static that we use in MIR. |
1b1a35ee | 627 | pub fn static_ptr_ty(self, def_id: DefId) -> Ty<'tcx> { |
60c5eb7d | 628 | // Make sure that any constants in the static's type are evaluated. |
9ffffee4 FG |
629 | let static_ty = self.normalize_erasing_regions( |
630 | ty::ParamEnv::empty(), | |
631 | self.type_of(def_id).subst_identity(), | |
632 | ); | |
60c5eb7d | 633 | |
29967ef6 XL |
634 | // Make sure that accesses to unsafe statics end up using raw pointers. |
635 | // For thread-locals, this needs to be kept in sync with `Rvalue::ty`. | |
60c5eb7d XL |
636 | if self.is_mutable_static(def_id) { |
637 | self.mk_mut_ptr(static_ty) | |
29967ef6 XL |
638 | } else if self.is_foreign_item(def_id) { |
639 | self.mk_imm_ptr(static_ty) | |
60c5eb7d XL |
640 | } else { |
641 | self.mk_imm_ref(self.lifetimes.re_erased, static_ty) | |
642 | } | |
abe05a73 | 643 | } |
0731742a | 644 | |
9ffffee4 FG |
645 | /// Return the set of types that should be taken into accound when checking |
646 | /// trait bounds on a generator's internal state. | |
647 | pub fn generator_hidden_types( | |
648 | self, | |
649 | def_id: DefId, | |
650 | ) -> impl Iterator<Item = ty::EarlyBinder<Ty<'tcx>>> { | |
651 | let generator_layout = &self.mir_generator_witnesses(def_id); | |
652 | generator_layout | |
653 | .field_tys | |
654 | .iter() | |
655 | .filter(|decl| !decl.ignore_for_traits) | |
656 | .map(|decl| ty::EarlyBinder(decl.ty)) | |
657 | } | |
658 | ||
659 | /// Normalizes all opaque types in the given value, replacing them | |
660 | /// with their underlying types. | |
661 | pub fn expand_opaque_types(self, val: Ty<'tcx>) -> Ty<'tcx> { | |
662 | let mut visitor = OpaqueTypeExpander { | |
663 | seen_opaque_tys: FxHashSet::default(), | |
664 | expanded_cache: FxHashMap::default(), | |
665 | primary_def_id: None, | |
666 | found_recursion: false, | |
667 | found_any_recursion: false, | |
668 | check_recursion: false, | |
669 | expand_generators: false, | |
670 | tcx: self, | |
671 | }; | |
672 | val.fold_with(&mut visitor) | |
673 | } | |
674 | ||
0731742a | 675 | /// Expands the given impl trait type, stopping if the type is recursive. |
f2b60f7d | 676 | #[instrument(skip(self), level = "debug", ret)] |
0731742a XL |
677 | pub fn try_expand_impl_trait_type( |
678 | self, | |
679 | def_id: DefId, | |
532ac7d7 | 680 | substs: SubstsRef<'tcx>, |
0731742a | 681 | ) -> Result<Ty<'tcx>, Ty<'tcx>> { |
0731742a XL |
682 | let mut visitor = OpaqueTypeExpander { |
683 | seen_opaque_tys: FxHashSet::default(), | |
e1599b0c | 684 | expanded_cache: FxHashMap::default(), |
3dfed10e | 685 | primary_def_id: Some(def_id), |
0731742a | 686 | found_recursion: false, |
94222f64 | 687 | found_any_recursion: false, |
3dfed10e | 688 | check_recursion: true, |
9ffffee4 | 689 | expand_generators: true, |
0731742a XL |
690 | tcx: self, |
691 | }; | |
3dfed10e | 692 | |
0731742a | 693 | let expanded_type = visitor.expand_opaque_ty(def_id, substs).unwrap(); |
dfeec247 | 694 | if visitor.found_recursion { Err(expanded_type) } else { Ok(expanded_type) } |
0731742a | 695 | } |
04454e1e | 696 | |
9c376795 | 697 | pub fn bound_return_position_impl_trait_in_trait_tys( |
f2b60f7d FG |
698 | self, |
699 | def_id: DefId, | |
700 | ) -> ty::EarlyBinder<Result<&'tcx FxHashMap<DefId, Ty<'tcx>>, ErrorGuaranteed>> { | |
9c376795 | 701 | ty::EarlyBinder(self.collect_return_position_impl_trait_in_trait_tys(def_id)) |
f2b60f7d FG |
702 | } |
703 | ||
04454e1e FG |
704 | pub fn bound_explicit_item_bounds( |
705 | self, | |
706 | def_id: DefId, | |
923072b8 FG |
707 | ) -> ty::EarlyBinder<&'tcx [(ty::Predicate<'tcx>, rustc_span::Span)]> { |
708 | ty::EarlyBinder(self.explicit_item_bounds(def_id)) | |
04454e1e FG |
709 | } |
710 | ||
9c376795 FG |
711 | /// Returns names of captured upvars for closures and generators. |
712 | /// | |
713 | /// Here are some examples: | |
714 | /// - `name__field1__field2` when the upvar is captured by value. | |
715 | /// - `_ref__name__field` when the upvar is captured by reference. | |
716 | /// | |
717 | /// For generators this only contains upvars that are shared by all states. | |
718 | pub fn closure_saved_names_of_captured_variables( | |
064997fb FG |
719 | self, |
720 | def_id: DefId, | |
9c376795 FG |
721 | ) -> SmallVec<[String; 16]> { |
722 | let body = self.optimized_mir(def_id); | |
723 | ||
724 | body.var_debug_info | |
725 | .iter() | |
726 | .filter_map(|var| { | |
727 | let is_ref = match var.value { | |
728 | mir::VarDebugInfoContents::Place(place) | |
729 | if place.local == mir::Local::new(1) => | |
730 | { | |
731 | // The projection is either `[.., Field, Deref]` or `[.., Field]`. It | |
732 | // implies whether the variable is captured by value or by reference. | |
733 | matches!(place.projection.last().unwrap(), mir::ProjectionElem::Deref) | |
734 | } | |
735 | _ => return None, | |
736 | }; | |
737 | let prefix = if is_ref { "_ref__" } else { "" }; | |
738 | Some(prefix.to_owned() + var.name.as_str()) | |
739 | }) | |
740 | .collect() | |
064997fb FG |
741 | } |
742 | ||
9c376795 FG |
743 | // FIXME(eddyb) maybe precompute this? Right now it's computed once |
744 | // per generator monomorphization, but it doesn't depend on substs. | |
745 | pub fn generator_layout_and_saved_local_names( | |
064997fb FG |
746 | self, |
747 | def_id: DefId, | |
9c376795 FG |
748 | ) -> ( |
749 | &'tcx ty::GeneratorLayout<'tcx>, | |
750 | IndexVec<mir::GeneratorSavedLocal, Option<rustc_span::Symbol>>, | |
751 | ) { | |
752 | let tcx = self; | |
753 | let body = tcx.optimized_mir(def_id); | |
754 | let generator_layout = body.generator_layout().unwrap(); | |
755 | let mut generator_saved_local_names = | |
756 | IndexVec::from_elem(None, &generator_layout.field_tys); | |
757 | ||
758 | let state_arg = mir::Local::new(1); | |
759 | for var in &body.var_debug_info { | |
760 | let mir::VarDebugInfoContents::Place(place) = &var.value else { continue }; | |
761 | if place.local != state_arg { | |
762 | continue; | |
763 | } | |
764 | match place.projection[..] { | |
765 | [ | |
766 | // Deref of the `Pin<&mut Self>` state argument. | |
767 | mir::ProjectionElem::Field(..), | |
768 | mir::ProjectionElem::Deref, | |
769 | // Field of a variant of the state. | |
770 | mir::ProjectionElem::Downcast(_, variant), | |
771 | mir::ProjectionElem::Field(field, _), | |
772 | ] => { | |
773 | let name = &mut generator_saved_local_names | |
774 | [generator_layout.variant_fields[variant][field]]; | |
775 | if name.is_none() { | |
776 | name.replace(var.name); | |
777 | } | |
778 | } | |
779 | _ => {} | |
780 | } | |
781 | } | |
782 | (generator_layout, generator_saved_local_names) | |
064997fb FG |
783 | } |
784 | ||
9ffffee4 FG |
785 | /// Query and get an English description for the item's kind. |
786 | pub fn def_descr(self, def_id: DefId) -> &'static str { | |
787 | self.def_kind_descr(self.def_kind(def_id), def_id) | |
788 | } | |
789 | ||
790 | /// Get an English description for the item's kind. | |
791 | pub fn def_kind_descr(self, def_kind: DefKind, def_id: DefId) -> &'static str { | |
792 | match def_kind { | |
793 | DefKind::AssocFn if self.associated_item(def_id).fn_has_self_parameter => "method", | |
794 | DefKind::Generator => match self.generator_kind(def_id).unwrap() { | |
795 | rustc_hir::GeneratorKind::Async(..) => "async closure", | |
796 | rustc_hir::GeneratorKind::Gen => "generator", | |
797 | }, | |
798 | _ => def_kind.descr(def_id), | |
799 | } | |
800 | } | |
801 | ||
802 | /// Gets an English article for the [`TyCtxt::def_descr`]. | |
803 | pub fn def_descr_article(self, def_id: DefId) -> &'static str { | |
804 | self.def_kind_descr_article(self.def_kind(def_id), def_id) | |
805 | } | |
806 | ||
807 | /// Gets an English article for the [`TyCtxt::def_kind_descr`]. | |
808 | pub fn def_kind_descr_article(self, def_kind: DefKind, def_id: DefId) -> &'static str { | |
809 | match def_kind { | |
810 | DefKind::AssocFn if self.associated_item(def_id).fn_has_self_parameter => "a", | |
811 | DefKind::Generator => match self.generator_kind(def_id).unwrap() { | |
812 | rustc_hir::GeneratorKind::Async(..) => "an", | |
813 | rustc_hir::GeneratorKind::Gen => "a", | |
814 | }, | |
815 | _ => def_kind.article(), | |
816 | } | |
064997fb | 817 | } |
9e0c209e SL |
818 | } |
819 | ||
3dfed10e XL |
820 | struct OpaqueTypeExpander<'tcx> { |
821 | // Contains the DefIds of the opaque types that are currently being | |
822 | // expanded. When we expand an opaque type we insert the DefId of | |
823 | // that type, and when we finish expanding that type we remove the | |
824 | // its DefId. | |
825 | seen_opaque_tys: FxHashSet<DefId>, | |
826 | // Cache of all expansions we've seen so far. This is a critical | |
827 | // optimization for some large types produced by async fn trees. | |
828 | expanded_cache: FxHashMap<(DefId, SubstsRef<'tcx>), Ty<'tcx>>, | |
829 | primary_def_id: Option<DefId>, | |
830 | found_recursion: bool, | |
94222f64 | 831 | found_any_recursion: bool, |
9ffffee4 | 832 | expand_generators: bool, |
3dfed10e XL |
833 | /// Whether or not to check for recursive opaque types. |
834 | /// This is `true` when we're explicitly checking for opaque type | |
835 | /// recursion, and 'false' otherwise to avoid unnecessary work. | |
836 | check_recursion: bool, | |
837 | tcx: TyCtxt<'tcx>, | |
838 | } | |
839 | ||
840 | impl<'tcx> OpaqueTypeExpander<'tcx> { | |
841 | fn expand_opaque_ty(&mut self, def_id: DefId, substs: SubstsRef<'tcx>) -> Option<Ty<'tcx>> { | |
94222f64 | 842 | if self.found_any_recursion { |
3dfed10e XL |
843 | return None; |
844 | } | |
845 | let substs = substs.fold_with(self); | |
846 | if !self.check_recursion || self.seen_opaque_tys.insert(def_id) { | |
847 | let expanded_ty = match self.expanded_cache.get(&(def_id, substs)) { | |
5099ac24 | 848 | Some(expanded_ty) => *expanded_ty, |
3dfed10e | 849 | None => { |
9ffffee4 | 850 | let generic_ty = self.tcx.type_of(def_id); |
3dfed10e XL |
851 | let concrete_ty = generic_ty.subst(self.tcx, substs); |
852 | let expanded_ty = self.fold_ty(concrete_ty); | |
853 | self.expanded_cache.insert((def_id, substs), expanded_ty); | |
854 | expanded_ty | |
855 | } | |
856 | }; | |
857 | if self.check_recursion { | |
858 | self.seen_opaque_tys.remove(&def_id); | |
859 | } | |
860 | Some(expanded_ty) | |
861 | } else { | |
862 | // If another opaque type that we contain is recursive, then it | |
863 | // will report the error, so we don't have to. | |
94222f64 | 864 | self.found_any_recursion = true; |
3dfed10e XL |
865 | self.found_recursion = def_id == *self.primary_def_id.as_ref().unwrap(); |
866 | None | |
867 | } | |
868 | } | |
9ffffee4 FG |
869 | |
870 | fn expand_generator(&mut self, def_id: DefId, substs: SubstsRef<'tcx>) -> Option<Ty<'tcx>> { | |
871 | if self.found_any_recursion { | |
872 | return None; | |
873 | } | |
874 | let substs = substs.fold_with(self); | |
875 | if !self.check_recursion || self.seen_opaque_tys.insert(def_id) { | |
876 | let expanded_ty = match self.expanded_cache.get(&(def_id, substs)) { | |
877 | Some(expanded_ty) => *expanded_ty, | |
878 | None => { | |
879 | for bty in self.tcx.generator_hidden_types(def_id) { | |
880 | let hidden_ty = bty.subst(self.tcx, substs); | |
881 | self.fold_ty(hidden_ty); | |
882 | } | |
883 | let expanded_ty = self.tcx.mk_generator_witness_mir(def_id, substs); | |
884 | self.expanded_cache.insert((def_id, substs), expanded_ty); | |
885 | expanded_ty | |
886 | } | |
887 | }; | |
888 | if self.check_recursion { | |
889 | self.seen_opaque_tys.remove(&def_id); | |
890 | } | |
891 | Some(expanded_ty) | |
892 | } else { | |
893 | // If another opaque type that we contain is recursive, then it | |
894 | // will report the error, so we don't have to. | |
895 | self.found_any_recursion = true; | |
896 | self.found_recursion = def_id == *self.primary_def_id.as_ref().unwrap(); | |
897 | None | |
898 | } | |
899 | } | |
3dfed10e XL |
900 | } |
901 | ||
9ffffee4 FG |
902 | impl<'tcx> TypeFolder<TyCtxt<'tcx>> for OpaqueTypeExpander<'tcx> { |
903 | fn interner(&self) -> TyCtxt<'tcx> { | |
3dfed10e XL |
904 | self.tcx |
905 | } | |
906 | ||
907 | fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> { | |
9ffffee4 | 908 | let mut t = if let ty::Alias(ty::Opaque, ty::AliasTy { def_id, substs, .. }) = *t.kind() { |
3dfed10e | 909 | self.expand_opaque_ty(def_id, substs).unwrap_or(t) |
9ffffee4 | 910 | } else if t.has_opaque_types() || t.has_generators() { |
3dfed10e XL |
911 | t.super_fold_with(self) |
912 | } else { | |
913 | t | |
9ffffee4 FG |
914 | }; |
915 | if self.expand_generators { | |
916 | if let ty::GeneratorWitnessMIR(def_id, substs) = *t.kind() { | |
917 | t = self.expand_generator(def_id, substs).unwrap_or(t); | |
918 | } | |
919 | } | |
920 | t | |
921 | } | |
922 | ||
923 | fn fold_predicate(&mut self, p: ty::Predicate<'tcx>) -> ty::Predicate<'tcx> { | |
924 | if let ty::PredicateKind::Clause(clause) = p.kind().skip_binder() | |
925 | && let ty::Clause::Projection(projection_pred) = clause | |
926 | { | |
927 | p.kind() | |
928 | .rebind(ty::ProjectionPredicate { | |
929 | projection_ty: projection_pred.projection_ty.fold_with(self), | |
930 | // Don't fold the term on the RHS of the projection predicate. | |
931 | // This is because for default trait methods with RPITITs, we | |
932 | // install a `NormalizesTo(Projection(RPITIT) -> Opaque(RPITIT))` | |
933 | // predicate, which would trivially cause a cycle when we do | |
934 | // anything that requires `ParamEnv::with_reveal_all_normalized`. | |
935 | term: projection_pred.term, | |
936 | }) | |
937 | .to_predicate(self.tcx) | |
938 | } else { | |
939 | p.super_fold_with(self) | |
3dfed10e XL |
940 | } |
941 | } | |
942 | } | |
943 | ||
5099ac24 | 944 | impl<'tcx> Ty<'tcx> { |
353b0b11 FG |
945 | pub fn int_size_and_signed(self, tcx: TyCtxt<'tcx>) -> (Size, bool) { |
946 | let (int, signed) = match *self.kind() { | |
947 | ty::Int(ity) => (Integer::from_int_ty(&tcx, ity), true), | |
948 | ty::Uint(uty) => (Integer::from_uint_ty(&tcx, uty), false), | |
949 | _ => bug!("non integer discriminant"), | |
950 | }; | |
951 | (int.size(), signed) | |
952 | } | |
953 | ||
dfeec247 XL |
954 | /// Returns the maximum value for the given numeric type (including `char`s) |
955 | /// or returns `None` if the type is not numeric. | |
923072b8 | 956 | pub fn numeric_max_val(self, tcx: TyCtxt<'tcx>) -> Option<ty::Const<'tcx>> { |
1b1a35ee | 957 | let val = match self.kind() { |
dfeec247 | 958 | ty::Int(_) | ty::Uint(_) => { |
353b0b11 | 959 | let (size, signed) = self.int_size_and_signed(tcx); |
c295e0f8 XL |
960 | let val = |
961 | if signed { size.signed_int_max() as u128 } else { size.unsigned_int_max() }; | |
dfeec247 XL |
962 | Some(val) |
963 | } | |
964 | ty::Char => Some(std::char::MAX as u128), | |
965 | ty::Float(fty) => Some(match fty { | |
5869c6ff XL |
966 | ty::FloatTy::F32 => rustc_apfloat::ieee::Single::INFINITY.to_bits(), |
967 | ty::FloatTy::F64 => rustc_apfloat::ieee::Double::INFINITY.to_bits(), | |
dfeec247 XL |
968 | }), |
969 | _ => None, | |
970 | }; | |
923072b8 FG |
971 | |
972 | val.map(|v| ty::Const::from_bits(tcx, v, ty::ParamEnv::empty().and(self))) | |
dfeec247 XL |
973 | } |
974 | ||
975 | /// Returns the minimum value for the given numeric type (including `char`s) | |
976 | /// or returns `None` if the type is not numeric. | |
923072b8 | 977 | pub fn numeric_min_val(self, tcx: TyCtxt<'tcx>) -> Option<ty::Const<'tcx>> { |
1b1a35ee | 978 | let val = match self.kind() { |
dfeec247 | 979 | ty::Int(_) | ty::Uint(_) => { |
353b0b11 | 980 | let (size, signed) = self.int_size_and_signed(tcx); |
c295e0f8 | 981 | let val = if signed { size.truncate(size.signed_int_min() as u128) } else { 0 }; |
dfeec247 XL |
982 | Some(val) |
983 | } | |
984 | ty::Char => Some(0), | |
985 | ty::Float(fty) => Some(match fty { | |
5869c6ff XL |
986 | ty::FloatTy::F32 => (-::rustc_apfloat::ieee::Single::INFINITY).to_bits(), |
987 | ty::FloatTy::F64 => (-::rustc_apfloat::ieee::Double::INFINITY).to_bits(), | |
dfeec247 XL |
988 | }), |
989 | _ => None, | |
990 | }; | |
923072b8 FG |
991 | |
992 | val.map(|v| ty::Const::from_bits(tcx, v, ty::ParamEnv::empty().and(self))) | |
dfeec247 XL |
993 | } |
994 | ||
0731742a XL |
995 | /// Checks whether values of this type `T` are *moved* or *copied* |
996 | /// when referenced -- this amounts to a check for whether `T: | |
997 | /// Copy`, but note that we **don't** consider lifetimes when | |
998 | /// doing this check. This means that we may generate MIR which | |
999 | /// does copies even when the type actually doesn't satisfy the | |
1000 | /// full requirements for the `Copy` trait (cc #29149) -- this | |
1001 | /// winds up being reported as an error during NLL borrow check. | |
2b03887a FG |
1002 | pub fn is_copy_modulo_regions(self, tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> bool { |
1003 | self.is_trivially_pure_clone_copy() || tcx.is_copy_raw(param_env.and(self)) | |
e9174d1e SL |
1004 | } |
1005 | ||
0731742a XL |
1006 | /// Checks whether values of this type `T` have a size known at |
1007 | /// compile time (i.e., whether `T: Sized`). Lifetimes are ignored | |
1008 | /// for the purposes of this check, so it can be an | |
1009 | /// over-approximation in generic contexts, where one can have | |
1010 | /// strange rules like `<T as Foo<'static>>::Bar: Sized` that | |
1011 | /// actually carry lifetime requirements. | |
2b03887a FG |
1012 | pub fn is_sized(self, tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> bool { |
1013 | self.is_trivially_sized(tcx) || tcx.is_sized_raw(param_env.and(self)) | |
e9174d1e SL |
1014 | } |
1015 | ||
0731742a | 1016 | /// Checks whether values of this type `T` implement the `Freeze` |
94222f64 | 1017 | /// trait -- frozen types are those that do not contain an |
9fa01778 | 1018 | /// `UnsafeCell` anywhere. This is a language concept used to |
0731742a XL |
1019 | /// distinguish "true immutability", which is relevant to |
1020 | /// optimization as well as the rules around static values. Note | |
1021 | /// that the `Freeze` trait is not exposed to end users and is | |
1022 | /// effectively an implementation detail. | |
2b03887a FG |
1023 | pub fn is_freeze(self, tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> bool { |
1024 | self.is_trivially_freeze() || tcx.is_freeze_raw(param_env.and(self)) | |
74b04a01 XL |
1025 | } |
1026 | ||
1027 | /// Fast path helper for testing if a type is `Freeze`. | |
1028 | /// | |
1029 | /// Returning true means the type is known to be `Freeze`. Returning | |
1030 | /// `false` means nothing -- could be `Freeze`, might not be. | |
5099ac24 | 1031 | fn is_trivially_freeze(self) -> bool { |
1b1a35ee | 1032 | match self.kind() { |
74b04a01 XL |
1033 | ty::Int(_) |
1034 | | ty::Uint(_) | |
1035 | | ty::Float(_) | |
1036 | | ty::Bool | |
1037 | | ty::Char | |
1038 | | ty::Str | |
1039 | | ty::Never | |
1040 | | ty::Ref(..) | |
1041 | | ty::RawPtr(_) | |
1042 | | ty::FnDef(..) | |
f035d41b | 1043 | | ty::Error(_) |
74b04a01 | 1044 | | ty::FnPtr(_) => true, |
5e7ed085 | 1045 | ty::Tuple(fields) => fields.iter().all(Self::is_trivially_freeze), |
74b04a01 XL |
1046 | ty::Slice(elem_ty) | ty::Array(elem_ty, _) => elem_ty.is_trivially_freeze(), |
1047 | ty::Adt(..) | |
1048 | | ty::Bound(..) | |
1049 | | ty::Closure(..) | |
1050 | | ty::Dynamic(..) | |
1051 | | ty::Foreign(_) | |
1052 | | ty::Generator(..) | |
1053 | | ty::GeneratorWitness(_) | |
9ffffee4 | 1054 | | ty::GeneratorWitnessMIR(..) |
74b04a01 | 1055 | | ty::Infer(_) |
9c376795 | 1056 | | ty::Alias(..) |
74b04a01 | 1057 | | ty::Param(_) |
9c376795 | 1058 | | ty::Placeholder(_) => false, |
74b04a01 | 1059 | } |
cc61c64b XL |
1060 | } |
1061 | ||
cdc7bbd5 | 1062 | /// Checks whether values of this type `T` implement the `Unpin` trait. |
2b03887a FG |
1063 | pub fn is_unpin(self, tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> bool { |
1064 | self.is_trivially_unpin() || tcx.is_unpin_raw(param_env.and(self)) | |
cdc7bbd5 XL |
1065 | } |
1066 | ||
1067 | /// Fast path helper for testing if a type is `Unpin`. | |
1068 | /// | |
1069 | /// Returning true means the type is known to be `Unpin`. Returning | |
1070 | /// `false` means nothing -- could be `Unpin`, might not be. | |
5099ac24 | 1071 | fn is_trivially_unpin(self) -> bool { |
cdc7bbd5 XL |
1072 | match self.kind() { |
1073 | ty::Int(_) | |
1074 | | ty::Uint(_) | |
1075 | | ty::Float(_) | |
1076 | | ty::Bool | |
1077 | | ty::Char | |
1078 | | ty::Str | |
1079 | | ty::Never | |
1080 | | ty::Ref(..) | |
1081 | | ty::RawPtr(_) | |
1082 | | ty::FnDef(..) | |
1083 | | ty::Error(_) | |
1084 | | ty::FnPtr(_) => true, | |
5e7ed085 | 1085 | ty::Tuple(fields) => fields.iter().all(Self::is_trivially_unpin), |
cdc7bbd5 XL |
1086 | ty::Slice(elem_ty) | ty::Array(elem_ty, _) => elem_ty.is_trivially_unpin(), |
1087 | ty::Adt(..) | |
1088 | | ty::Bound(..) | |
1089 | | ty::Closure(..) | |
1090 | | ty::Dynamic(..) | |
1091 | | ty::Foreign(_) | |
1092 | | ty::Generator(..) | |
1093 | | ty::GeneratorWitness(_) | |
9ffffee4 | 1094 | | ty::GeneratorWitnessMIR(..) |
cdc7bbd5 | 1095 | | ty::Infer(_) |
9c376795 | 1096 | | ty::Alias(..) |
cdc7bbd5 | 1097 | | ty::Param(_) |
9c376795 | 1098 | | ty::Placeholder(_) => false, |
cdc7bbd5 XL |
1099 | } |
1100 | } | |
1101 | ||
cc61c64b XL |
1102 | /// If `ty.needs_drop(...)` returns `true`, then `ty` is definitely |
1103 | /// non-copy and *might* have a destructor attached; if it returns | |
0731742a | 1104 | /// `false`, then `ty` definitely has no destructor (i.e., no drop glue). |
cc61c64b XL |
1105 | /// |
1106 | /// (Note that this implies that if `ty` has a destructor attached, | |
1107 | /// then `needs_drop` will definitely return `true` for `ty`.) | |
e74abb32 XL |
1108 | /// |
1109 | /// Note that this method is used to check eligible types in unions. | |
cc61c64b | 1110 | #[inline] |
5099ac24 | 1111 | pub fn needs_drop(self, tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> bool { |
74b04a01 XL |
1112 | // Avoid querying in simple cases. |
1113 | match needs_drop_components(self, &tcx.data_layout) { | |
1114 | Err(AlwaysRequiresDrop) => true, | |
1115 | Ok(components) => { | |
1116 | let query_ty = match *components { | |
1117 | [] => return false, | |
1118 | // If we've got a single component, call the query with that | |
1119 | // to increase the chance that we hit the query cache. | |
1120 | [component_ty] => component_ty, | |
1121 | _ => self, | |
1122 | }; | |
a2a8927a | 1123 | |
74b04a01 XL |
1124 | // This doesn't depend on regions, so try to minimize distinct |
1125 | // query keys used. | |
a2a8927a XL |
1126 | // If normalization fails, we just use `query_ty`. |
1127 | let query_ty = | |
1128 | tcx.try_normalize_erasing_regions(param_env, query_ty).unwrap_or(query_ty); | |
1129 | ||
1130 | tcx.needs_drop_raw(param_env.and(query_ty)) | |
74b04a01 XL |
1131 | } |
1132 | } | |
cc61c64b XL |
1133 | } |
1134 | ||
2b03887a | 1135 | /// Checks if `ty` has a significant drop. |
17df50a5 XL |
1136 | /// |
1137 | /// Note that this method can return false even if `ty` has a destructor | |
1138 | /// attached; even if that is the case then the adt has been marked with | |
1139 | /// the attribute `rustc_insignificant_dtor`. | |
1140 | /// | |
1141 | /// Note that this method is used to check for change in drop order for | |
1142 | /// 2229 drop reorder migration analysis. | |
1143 | #[inline] | |
5099ac24 | 1144 | pub fn has_significant_drop(self, tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> bool { |
17df50a5 XL |
1145 | // Avoid querying in simple cases. |
1146 | match needs_drop_components(self, &tcx.data_layout) { | |
1147 | Err(AlwaysRequiresDrop) => true, | |
1148 | Ok(components) => { | |
1149 | let query_ty = match *components { | |
1150 | [] => return false, | |
1151 | // If we've got a single component, call the query with that | |
1152 | // to increase the chance that we hit the query cache. | |
1153 | [component_ty] => component_ty, | |
1154 | _ => self, | |
1155 | }; | |
136023e0 XL |
1156 | |
1157 | // FIXME(#86868): We should be canonicalizing, or else moving this to a method of inference | |
1158 | // context, or *something* like that, but for now just avoid passing inference | |
1159 | // variables to queries that can't cope with them. Instead, conservatively | |
1160 | // return "true" (may change drop order). | |
1161 | if query_ty.needs_infer() { | |
1162 | return true; | |
1163 | } | |
1164 | ||
17df50a5 XL |
1165 | // This doesn't depend on regions, so try to minimize distinct |
1166 | // query keys used. | |
1167 | let erased = tcx.normalize_erasing_regions(param_env, query_ty); | |
1168 | tcx.has_significant_drop_raw(param_env.and(erased)) | |
1169 | } | |
1170 | } | |
1171 | } | |
1172 | ||
f035d41b XL |
1173 | /// Returns `true` if equality for this type is both reflexive and structural. |
1174 | /// | |
1175 | /// Reflexive equality for a type is indicated by an `Eq` impl for that type. | |
1176 | /// | |
1177 | /// Primitive types (`u32`, `str`) have structural equality by definition. For composite data | |
1178 | /// types, equality for the type as a whole is structural when it is the same as equality | |
1179 | /// between all components (fields, array elements, etc.) of that type. For ADTs, structural | |
1180 | /// equality is indicated by an implementation of `PartialStructuralEq` and `StructuralEq` for | |
1181 | /// that type. | |
1182 | /// | |
1183 | /// This function is "shallow" because it may return `true` for a composite type whose fields | |
1184 | /// are not `StructuralEq`. For example, `[T; 4]` has structural equality regardless of `T` | |
1185 | /// because equality for arrays is determined by the equality of each array element. If you | |
1186 | /// want to know whether a given call to `PartialEq::eq` will proceed structurally all the way | |
1187 | /// down, you will need to use a type visitor. | |
1188 | #[inline] | |
5099ac24 | 1189 | pub fn is_structural_eq_shallow(self, tcx: TyCtxt<'tcx>) -> bool { |
1b1a35ee | 1190 | match self.kind() { |
f035d41b | 1191 | // Look for an impl of both `PartialStructuralEq` and `StructuralEq`. |
923072b8 | 1192 | ty::Adt(..) => tcx.has_structural_eq_impls(self), |
f035d41b XL |
1193 | |
1194 | // Primitive types that satisfy `Eq`. | |
923072b8 | 1195 | ty::Bool | ty::Char | ty::Int(_) | ty::Uint(_) | ty::Str | ty::Never => true, |
f035d41b XL |
1196 | |
1197 | // Composite types that satisfy `Eq` when all of their fields do. | |
1198 | // | |
1199 | // Because this function is "shallow", we return `true` for these composites regardless | |
1200 | // of the type(s) contained within. | |
923072b8 | 1201 | ty::Ref(..) | ty::Array(..) | ty::Slice(_) | ty::Tuple(..) => true, |
f035d41b XL |
1202 | |
1203 | // Raw pointers use bitwise comparison. | |
923072b8 | 1204 | ty::RawPtr(_) | ty::FnPtr(_) => true, |
f035d41b XL |
1205 | |
1206 | // Floating point numbers are not `Eq`. | |
923072b8 | 1207 | ty::Float(_) => false, |
f035d41b XL |
1208 | |
1209 | // Conservatively return `false` for all others... | |
1210 | ||
1211 | // Anonymous function types | |
923072b8 | 1212 | ty::FnDef(..) | ty::Closure(..) | ty::Dynamic(..) | ty::Generator(..) => false, |
f035d41b XL |
1213 | |
1214 | // Generic or inferred types | |
1215 | // | |
1216 | // FIXME(ecstaticmorse): Maybe we should `bug` here? This should probably only be | |
1217 | // called for known, fully-monomorphized types. | |
9c376795 FG |
1218 | ty::Alias(..) | ty::Param(_) | ty::Bound(..) | ty::Placeholder(_) | ty::Infer(_) => { |
1219 | false | |
1220 | } | |
f035d41b | 1221 | |
9ffffee4 FG |
1222 | ty::Foreign(_) |
1223 | | ty::GeneratorWitness(..) | |
1224 | | ty::GeneratorWitnessMIR(..) | |
1225 | | ty::Error(_) => false, | |
f035d41b XL |
1226 | } |
1227 | } | |
1228 | ||
e1599b0c XL |
1229 | /// Peel off all reference types in this type until there are none left. |
1230 | /// | |
1231 | /// This method is idempotent, i.e. `ty.peel_refs().peel_refs() == ty.peel_refs()`. | |
1232 | /// | |
1233 | /// # Examples | |
1234 | /// | |
1235 | /// - `u8` -> `u8` | |
1236 | /// - `&'a mut u8` -> `u8` | |
1237 | /// - `&'a &'b u8` -> `u8` | |
1238 | /// - `&'a *const &'b u8 -> *const &'b u8` | |
5099ac24 | 1239 | pub fn peel_refs(self) -> Ty<'tcx> { |
e1599b0c | 1240 | let mut ty = self; |
923072b8 | 1241 | while let ty::Ref(_, inner_ty, _) = ty.kind() { |
5099ac24 | 1242 | ty = *inner_ty; |
e1599b0c XL |
1243 | } |
1244 | ty | |
1245 | } | |
136023e0 | 1246 | |
064997fb | 1247 | #[inline] |
923072b8 | 1248 | pub fn outer_exclusive_binder(self) -> ty::DebruijnIndex { |
5099ac24 | 1249 | self.0.outer_exclusive_binder |
136023e0 | 1250 | } |
e9174d1e | 1251 | } |
7cac9316 | 1252 | |
abe05a73 XL |
1253 | pub enum ExplicitSelf<'tcx> { |
1254 | ByValue, | |
1255 | ByReference(ty::Region<'tcx>, hir::Mutability), | |
ff7c6d11 | 1256 | ByRawPointer(hir::Mutability), |
abe05a73 | 1257 | ByBox, |
dfeec247 | 1258 | Other, |
abe05a73 XL |
1259 | } |
1260 | ||
1261 | impl<'tcx> ExplicitSelf<'tcx> { | |
1262 | /// Categorizes an explicit self declaration like `self: SomeType` | |
1263 | /// into either `self`, `&self`, `&mut self`, `Box<self>`, or | |
1264 | /// `Other`. | |
1265 | /// This is mainly used to require the arbitrary_self_types feature | |
1266 | /// in the case of `Other`, to improve error messages in the common cases, | |
1267 | /// and to make `Other` non-object-safe. | |
1268 | /// | |
1269 | /// Examples: | |
1270 | /// | |
04454e1e | 1271 | /// ```ignore (illustrative) |
abe05a73 XL |
1272 | /// impl<'a> Foo for &'a T { |
1273 | /// // Legal declarations: | |
1274 | /// fn method1(self: &&'a T); // ExplicitSelf::ByReference | |
1275 | /// fn method2(self: &'a T); // ExplicitSelf::ByValue | |
1276 | /// fn method3(self: Box<&'a T>); // ExplicitSelf::ByBox | |
1277 | /// fn method4(self: Rc<&'a T>); // ExplicitSelf::Other | |
1278 | /// | |
1279 | /// // Invalid cases will be caught by `check_method_receiver`: | |
1280 | /// fn method_err1(self: &'a mut T); // ExplicitSelf::Other | |
1281 | /// fn method_err2(self: &'static T) // ExplicitSelf::ByValue | |
1282 | /// fn method_err3(self: &&T) // ExplicitSelf::ByReference | |
1283 | /// } | |
1284 | /// ``` | |
1285 | /// | |
dfeec247 | 1286 | pub fn determine<P>(self_arg_ty: Ty<'tcx>, is_self_ty: P) -> ExplicitSelf<'tcx> |
abe05a73 | 1287 | where |
dfeec247 | 1288 | P: Fn(Ty<'tcx>) -> bool, |
abe05a73 XL |
1289 | { |
1290 | use self::ExplicitSelf::*; | |
1291 | ||
1b1a35ee | 1292 | match *self_arg_ty.kind() { |
abe05a73 | 1293 | _ if is_self_ty(self_arg_ty) => ByValue, |
dfeec247 XL |
1294 | ty::Ref(region, ty, mutbl) if is_self_ty(ty) => ByReference(region, mutbl), |
1295 | ty::RawPtr(ty::TypeAndMut { ty, mutbl }) if is_self_ty(ty) => ByRawPointer(mutbl), | |
1296 | ty::Adt(def, _) if def.is_box() && is_self_ty(self_arg_ty.boxed_ty()) => ByBox, | |
1297 | _ => Other, | |
abe05a73 XL |
1298 | } |
1299 | } | |
1300 | } | |
74b04a01 XL |
1301 | |
1302 | /// Returns a list of types such that the given type needs drop if and only if | |
1303 | /// *any* of the returned types need drop. Returns `Err(AlwaysRequiresDrop)` if | |
1304 | /// this type always needs drop. | |
a2a8927a | 1305 | pub fn needs_drop_components<'tcx>( |
74b04a01 XL |
1306 | ty: Ty<'tcx>, |
1307 | target_layout: &TargetDataLayout, | |
1308 | ) -> Result<SmallVec<[Ty<'tcx>; 2]>, AlwaysRequiresDrop> { | |
1b1a35ee | 1309 | match ty.kind() { |
74b04a01 XL |
1310 | ty::Infer(ty::FreshIntTy(_)) |
1311 | | ty::Infer(ty::FreshFloatTy(_)) | |
1312 | | ty::Bool | |
1313 | | ty::Int(_) | |
1314 | | ty::Uint(_) | |
1315 | | ty::Float(_) | |
1316 | | ty::Never | |
1317 | | ty::FnDef(..) | |
1318 | | ty::FnPtr(_) | |
1319 | | ty::Char | |
1320 | | ty::GeneratorWitness(..) | |
9ffffee4 | 1321 | | ty::GeneratorWitnessMIR(..) |
74b04a01 XL |
1322 | | ty::RawPtr(_) |
1323 | | ty::Ref(..) | |
1324 | | ty::Str => Ok(SmallVec::new()), | |
1325 | ||
1326 | // Foreign types can never have destructors. | |
1327 | ty::Foreign(..) => Ok(SmallVec::new()), | |
1328 | ||
f035d41b | 1329 | ty::Dynamic(..) | ty::Error(_) => Err(AlwaysRequiresDrop), |
74b04a01 | 1330 | |
5099ac24 | 1331 | ty::Slice(ty) => needs_drop_components(*ty, target_layout), |
74b04a01 | 1332 | ty::Array(elem_ty, size) => { |
5099ac24 | 1333 | match needs_drop_components(*elem_ty, target_layout) { |
74b04a01 | 1334 | Ok(v) if v.is_empty() => Ok(v), |
923072b8 | 1335 | res => match size.kind().try_to_bits(target_layout.pointer_size) { |
74b04a01 XL |
1336 | // Arrays of size zero don't need drop, even if their element |
1337 | // type does. | |
1338 | Some(0) => Ok(SmallVec::new()), | |
1339 | Some(_) => res, | |
1340 | // We don't know which of the cases above we are in, so | |
1341 | // return the whole type and let the caller decide what to | |
1342 | // do. | |
1343 | None => Ok(smallvec![ty]), | |
1344 | }, | |
1345 | } | |
1346 | } | |
1347 | // If any field needs drop, then the whole tuple does. | |
5e7ed085 | 1348 | ty::Tuple(fields) => fields.iter().try_fold(SmallVec::new(), move |mut acc, elem| { |
74b04a01 XL |
1349 | acc.extend(needs_drop_components(elem, target_layout)?); |
1350 | Ok(acc) | |
1351 | }), | |
1352 | ||
1353 | // These require checking for `Copy` bounds or `Adt` destructors. | |
1354 | ty::Adt(..) | |
9c376795 | 1355 | | ty::Alias(..) |
74b04a01 XL |
1356 | | ty::Param(_) |
1357 | | ty::Bound(..) | |
1358 | | ty::Placeholder(..) | |
74b04a01 | 1359 | | ty::Infer(_) |
ba9703b0 XL |
1360 | | ty::Closure(..) |
1361 | | ty::Generator(..) => Ok(smallvec![ty]), | |
74b04a01 XL |
1362 | } |
1363 | } | |
1364 | ||
9c376795 | 1365 | pub fn is_trivially_const_drop(ty: Ty<'_>) -> bool { |
5099ac24 FG |
1366 | match *ty.kind() { |
1367 | ty::Bool | |
1368 | | ty::Char | |
1369 | | ty::Int(_) | |
1370 | | ty::Uint(_) | |
1371 | | ty::Float(_) | |
1372 | | ty::Infer(ty::IntVar(_)) | |
1373 | | ty::Infer(ty::FloatVar(_)) | |
1374 | | ty::Str | |
1375 | | ty::RawPtr(_) | |
1376 | | ty::Ref(..) | |
1377 | | ty::FnDef(..) | |
1378 | | ty::FnPtr(_) | |
1379 | | ty::Never | |
1380 | | ty::Foreign(_) => true, | |
1381 | ||
9c376795 | 1382 | ty::Alias(..) |
5099ac24 FG |
1383 | | ty::Dynamic(..) |
1384 | | ty::Error(_) | |
1385 | | ty::Bound(..) | |
1386 | | ty::Param(_) | |
1387 | | ty::Placeholder(_) | |
5099ac24 FG |
1388 | | ty::Infer(_) => false, |
1389 | ||
1390 | // Not trivial because they have components, and instead of looking inside, | |
1391 | // we'll just perform trait selection. | |
9ffffee4 FG |
1392 | ty::Closure(..) |
1393 | | ty::Generator(..) | |
1394 | | ty::GeneratorWitness(_) | |
1395 | | ty::GeneratorWitnessMIR(..) | |
1396 | | ty::Adt(..) => false, | |
5099ac24 FG |
1397 | |
1398 | ty::Array(ty, _) | ty::Slice(ty) => is_trivially_const_drop(ty), | |
1399 | ||
5e7ed085 | 1400 | ty::Tuple(tys) => tys.iter().all(|ty| is_trivially_const_drop(ty)), |
5099ac24 FG |
1401 | } |
1402 | } | |
1403 | ||
487cf647 FG |
1404 | /// Does the equivalent of |
1405 | /// ```ignore (ilustrative) | |
1406 | /// let v = self.iter().map(|p| p.fold_with(folder)).collect::<SmallVec<[_; 8]>>(); | |
1407 | /// folder.tcx().intern_*(&v) | |
1408 | /// ``` | |
fc512014 XL |
1409 | pub fn fold_list<'tcx, F, T>( |
1410 | list: &'tcx ty::List<T>, | |
1411 | folder: &mut F, | |
1412 | intern: impl FnOnce(TyCtxt<'tcx>, &[T]) -> &'tcx ty::List<T>, | |
a2a8927a | 1413 | ) -> Result<&'tcx ty::List<T>, F::Error> |
fc512014 | 1414 | where |
9ffffee4 FG |
1415 | F: FallibleTypeFolder<TyCtxt<'tcx>>, |
1416 | T: TypeFoldable<TyCtxt<'tcx>> + PartialEq + Copy, | |
fc512014 XL |
1417 | { |
1418 | let mut iter = list.iter(); | |
1419 | // Look for the first element that changed | |
a2a8927a XL |
1420 | match iter.by_ref().enumerate().find_map(|(i, t)| match t.try_fold_with(folder) { |
1421 | Ok(new_t) if new_t == t => None, | |
1422 | new_t => Some((i, new_t)), | |
fc512014 | 1423 | }) { |
a2a8927a XL |
1424 | Some((i, Ok(new_t))) => { |
1425 | // An element changed, prepare to intern the resulting list | |
1426 | let mut new_list = SmallVec::<[_; 8]>::with_capacity(list.len()); | |
1427 | new_list.extend_from_slice(&list[..i]); | |
1428 | new_list.push(new_t); | |
1429 | for t in iter { | |
1430 | new_list.push(t.try_fold_with(folder)?) | |
1431 | } | |
9ffffee4 | 1432 | Ok(intern(folder.interner(), &new_list)) |
a2a8927a XL |
1433 | } |
1434 | Some((_, Err(err))) => { | |
1435 | return Err(err); | |
1436 | } | |
1437 | None => Ok(list), | |
fc512014 XL |
1438 | } |
1439 | } | |
1440 | ||
3dfed10e | 1441 | #[derive(Copy, Clone, Debug, HashStable, TyEncodable, TyDecodable)] |
74b04a01 | 1442 | pub struct AlwaysRequiresDrop; |
3dfed10e | 1443 | |
487cf647 | 1444 | /// Reveals all opaque types in the given value, replacing them |
3dfed10e | 1445 | /// with their underlying types. |
487cf647 | 1446 | pub fn reveal_opaque_types_in_bounds<'tcx>( |
3dfed10e | 1447 | tcx: TyCtxt<'tcx>, |
923072b8 FG |
1448 | val: &'tcx ty::List<ty::Predicate<'tcx>>, |
1449 | ) -> &'tcx ty::List<ty::Predicate<'tcx>> { | |
3dfed10e XL |
1450 | let mut visitor = OpaqueTypeExpander { |
1451 | seen_opaque_tys: FxHashSet::default(), | |
1452 | expanded_cache: FxHashMap::default(), | |
1453 | primary_def_id: None, | |
1454 | found_recursion: false, | |
94222f64 | 1455 | found_any_recursion: false, |
3dfed10e | 1456 | check_recursion: false, |
9ffffee4 | 1457 | expand_generators: false, |
3dfed10e XL |
1458 | tcx, |
1459 | }; | |
1460 | val.fold_with(&mut visitor) | |
1461 | } | |
1462 | ||
5e7ed085 | 1463 | /// Determines whether an item is annotated with `doc(hidden)`. |
353b0b11 | 1464 | fn is_doc_hidden(tcx: TyCtxt<'_>, def_id: LocalDefId) -> bool { |
04454e1e FG |
1465 | tcx.get_attrs(def_id, sym::doc) |
1466 | .filter_map(|attr| attr.meta_item_list()) | |
5e7ed085 FG |
1467 | .any(|items| items.iter().any(|item| item.has_name(sym::hidden))) |
1468 | } | |
1469 | ||
2b03887a FG |
1470 | /// Determines whether an item is annotated with `doc(notable_trait)`. |
1471 | pub fn is_doc_notable_trait(tcx: TyCtxt<'_>, def_id: DefId) -> bool { | |
1472 | tcx.get_attrs(def_id, sym::doc) | |
1473 | .filter_map(|attr| attr.meta_item_list()) | |
1474 | .any(|items| items.iter().any(|item| item.has_name(sym::notable_trait))) | |
1475 | } | |
1476 | ||
923072b8 | 1477 | /// Determines whether an item is an intrinsic by Abi. |
353b0b11 | 1478 | pub fn is_intrinsic(tcx: TyCtxt<'_>, def_id: LocalDefId) -> bool { |
9ffffee4 | 1479 | matches!(tcx.fn_sig(def_id).skip_binder().abi(), Abi::RustIntrinsic | Abi::PlatformIntrinsic) |
923072b8 FG |
1480 | } |
1481 | ||
3dfed10e | 1482 | pub fn provide(providers: &mut ty::query::Providers) { |
2b03887a | 1483 | *providers = ty::query::Providers { |
487cf647 | 1484 | reveal_opaque_types_in_bounds, |
2b03887a FG |
1485 | is_doc_hidden, |
1486 | is_doc_notable_trait, | |
1487 | is_intrinsic, | |
1488 | ..*providers | |
1489 | } | |
3dfed10e | 1490 | } |