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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; |
a2a8927a | 4 | use crate::ty::fold::{FallibleTypeFolder, TypeFolder}; |
ba9703b0 | 5 | use crate::ty::layout::IntegerExt; |
9fa01778 | 6 | use crate::ty::query::TyCtxtAt; |
29967ef6 | 7 | use crate::ty::subst::{GenericArgKind, Subst, SubstsRef}; |
9fa01778 | 8 | use crate::ty::TyKind::*; |
136023e0 | 9 | use crate::ty::{self, DebruijnIndex, DefIdTree, List, Ty, TyCtxt, TypeFoldable}; |
dfeec247 | 10 | use rustc_apfloat::Float as _; |
3dfed10e | 11 | use rustc_ast as ast; |
74b04a01 | 12 | use rustc_attr::{self as attr, SignedInt, UnsignedInt}; |
0731742a | 13 | use rustc_data_structures::fx::{FxHashMap, FxHashSet}; |
dfeec247 | 14 | use rustc_data_structures::stable_hasher::{HashStable, StableHasher}; |
ba9703b0 | 15 | use rustc_errors::ErrorReported; |
dfeec247 XL |
16 | use rustc_hir as hir; |
17 | use rustc_hir::def::DefKind; | |
18 | use rustc_hir::def_id::DefId; | |
532ac7d7 | 19 | use rustc_macros::HashStable; |
c295e0f8 | 20 | use rustc_query_system::ich::NodeIdHashingMode; |
cdc7bbd5 | 21 | use rustc_span::DUMMY_SP; |
ba9703b0 | 22 | use rustc_target::abi::{Integer, Size, TargetDataLayout}; |
74b04a01 | 23 | use smallvec::SmallVec; |
cdc7bbd5 | 24 | use std::{fmt, iter}; |
e9174d1e | 25 | |
0531ce1d XL |
26 | #[derive(Copy, Clone, Debug)] |
27 | pub struct Discr<'tcx> { | |
9fa01778 | 28 | /// Bit representation of the discriminant (e.g., `-128i8` is `0xFF_u128`). |
0531ce1d | 29 | pub val: u128, |
dfeec247 | 30 | pub ty: Ty<'tcx>, |
0531ce1d | 31 | } |
8bb4bdeb | 32 | |
0531ce1d | 33 | impl<'tcx> fmt::Display for Discr<'tcx> { |
0bf4aa26 | 34 | fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result { |
1b1a35ee | 35 | match *self.ty.kind() { |
b7449926 | 36 | ty::Int(ity) => { |
5869c6ff | 37 | let size = ty::tls::with(|tcx| Integer::from_int_ty(&tcx, ity).size()); |
532ac7d7 | 38 | let x = self.val; |
0531ce1d | 39 | // sign extend the raw representation to be an i128 |
29967ef6 | 40 | let x = size.sign_extend(x) as i128; |
0531ce1d | 41 | write!(fmt, "{}", x) |
dfeec247 | 42 | } |
0531ce1d XL |
43 | _ => write!(fmt, "{}", self.val), |
44 | } | |
45 | } | |
cc61c64b | 46 | } |
8bb4bdeb | 47 | |
dfeec247 | 48 | fn int_size_and_signed<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> (Size, bool) { |
1b1a35ee | 49 | let (int, signed) = match *ty.kind() { |
5869c6ff XL |
50 | Int(ity) => (Integer::from_int_ty(&tcx, ity), true), |
51 | Uint(uty) => (Integer::from_uint_ty(&tcx, uty), false), | |
dfeec247 XL |
52 | _ => bug!("non integer discriminant"), |
53 | }; | |
54 | (int.size(), signed) | |
55 | } | |
56 | ||
0531ce1d | 57 | impl<'tcx> Discr<'tcx> { |
9fa01778 | 58 | /// Adds `1` to the value and wraps around if the maximum for the type is reached. |
dc9dc135 | 59 | pub fn wrap_incr(self, tcx: TyCtxt<'tcx>) -> Self { |
0531ce1d XL |
60 | self.checked_add(tcx, 1).0 |
61 | } | |
dc9dc135 | 62 | pub fn checked_add(self, tcx: TyCtxt<'tcx>, n: u128) -> (Self, bool) { |
dfeec247 XL |
63 | let (size, signed) = int_size_and_signed(tcx, self.ty); |
64 | let (val, oflo) = if signed { | |
c295e0f8 XL |
65 | let min = size.signed_int_min(); |
66 | let max = size.signed_int_max(); | |
29967ef6 | 67 | let val = size.sign_extend(self.val) as i128; |
74b04a01 | 68 | assert!(n < (i128::MAX as u128)); |
0531ce1d XL |
69 | let n = n as i128; |
70 | let oflo = val > max - n; | |
dfeec247 | 71 | let val = if oflo { min + (n - (max - val) - 1) } else { val + n }; |
0531ce1d XL |
72 | // zero the upper bits |
73 | let val = val as u128; | |
29967ef6 | 74 | let val = size.truncate(val); |
dfeec247 | 75 | (val, oflo) |
0531ce1d | 76 | } else { |
c295e0f8 | 77 | let max = size.unsigned_int_max(); |
0531ce1d XL |
78 | let val = self.val; |
79 | let oflo = val > max - n; | |
dfeec247 XL |
80 | let val = if oflo { n - (max - val) - 1 } else { val + n }; |
81 | (val, oflo) | |
82 | }; | |
83 | (Self { val, ty: self.ty }, oflo) | |
8bb4bdeb | 84 | } |
e9174d1e SL |
85 | } |
86 | ||
0531ce1d | 87 | pub trait IntTypeExt { |
dc9dc135 XL |
88 | fn to_ty<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Ty<'tcx>; |
89 | fn disr_incr<'tcx>(&self, tcx: TyCtxt<'tcx>, val: Option<Discr<'tcx>>) -> Option<Discr<'tcx>>; | |
90 | fn initial_discriminant<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Discr<'tcx>; | |
0531ce1d XL |
91 | } |
92 | ||
e9174d1e | 93 | impl IntTypeExt for attr::IntType { |
dc9dc135 | 94 | fn to_ty<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> { |
e9174d1e | 95 | match *self { |
dfeec247 XL |
96 | SignedInt(ast::IntTy::I8) => tcx.types.i8, |
97 | SignedInt(ast::IntTy::I16) => tcx.types.i16, | |
98 | SignedInt(ast::IntTy::I32) => tcx.types.i32, | |
99 | SignedInt(ast::IntTy::I64) => tcx.types.i64, | |
100 | SignedInt(ast::IntTy::I128) => tcx.types.i128, | |
101 | SignedInt(ast::IntTy::Isize) => tcx.types.isize, | |
102 | UnsignedInt(ast::UintTy::U8) => tcx.types.u8, | |
103 | UnsignedInt(ast::UintTy::U16) => tcx.types.u16, | |
104 | UnsignedInt(ast::UintTy::U32) => tcx.types.u32, | |
105 | UnsignedInt(ast::UintTy::U64) => tcx.types.u64, | |
106 | UnsignedInt(ast::UintTy::U128) => tcx.types.u128, | |
2c00a5a8 | 107 | UnsignedInt(ast::UintTy::Usize) => tcx.types.usize, |
e9174d1e SL |
108 | } |
109 | } | |
110 | ||
dc9dc135 | 111 | fn initial_discriminant<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Discr<'tcx> { |
dfeec247 | 112 | Discr { val: 0, ty: self.to_ty(tcx) } |
e9174d1e SL |
113 | } |
114 | ||
dc9dc135 | 115 | fn disr_incr<'tcx>(&self, tcx: TyCtxt<'tcx>, val: Option<Discr<'tcx>>) -> Option<Discr<'tcx>> { |
a7813a04 | 116 | if let Some(val) = val { |
0531ce1d XL |
117 | assert_eq!(self.to_ty(tcx), val.ty); |
118 | let (new, oflo) = val.checked_add(tcx, 1); | |
dfeec247 | 119 | if oflo { None } else { Some(new) } |
a7813a04 XL |
120 | } else { |
121 | Some(self.initial_discriminant(tcx)) | |
122 | } | |
e9174d1e SL |
123 | } |
124 | } | |
125 | ||
dc9dc135 | 126 | impl<'tcx> TyCtxt<'tcx> { |
cc61c64b XL |
127 | /// Creates a hash of the type `Ty` which will be the same no matter what crate |
128 | /// context it's calculated within. This is used by the `type_id` intrinsic. | |
129 | pub fn type_id_hash(self, ty: Ty<'tcx>) -> u64 { | |
130 | let mut hasher = StableHasher::new(); | |
ea8adc8c | 131 | let mut hcx = self.create_stable_hashing_context(); |
cc61c64b | 132 | |
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 | |
cc61c64b XL |
138 | hcx.while_hashing_spans(false, |hcx| { |
139 | hcx.with_node_id_hashing_mode(NodeIdHashingMode::HashDefPath, |hcx| { | |
140 | ty.hash_stable(hcx, &mut hasher); | |
141 | }); | |
142 | }); | |
143 | hasher.finish() | |
144 | } | |
cc61c64b | 145 | |
5bcae85e | 146 | pub fn has_error_field(self, ty: Ty<'tcx>) -> bool { |
1b1a35ee | 147 | if let ty::Adt(def, substs) = *ty.kind() { |
0bf4aa26 XL |
148 | for field in def.all_fields() { |
149 | let field_ty = field.ty(self, substs); | |
1b1a35ee | 150 | if let Error(_) = field_ty.kind() { |
0bf4aa26 | 151 | return true; |
5bcae85e SL |
152 | } |
153 | } | |
5bcae85e SL |
154 | } |
155 | false | |
156 | } | |
157 | ||
416331ca XL |
158 | /// Attempts to returns the deeply last field of nested structures, but |
159 | /// does not apply any normalization in its search. Returns the same type | |
160 | /// if input `ty` is not a structure at all. | |
dfeec247 | 161 | pub fn struct_tail_without_normalization(self, ty: Ty<'tcx>) -> Ty<'tcx> { |
416331ca XL |
162 | let tcx = self; |
163 | tcx.struct_tail_with_normalize(ty, |ty| ty) | |
164 | } | |
165 | ||
166 | /// Returns the deeply last field of nested structures, or the same type if | |
167 | /// not a structure at all. Corresponds to the only possible unsized field, | |
168 | /// and its type can be used to determine unsizing strategy. | |
169 | /// | |
170 | /// Should only be called if `ty` has no inference variables and does not | |
171 | /// need its lifetimes preserved (e.g. as part of codegen); otherwise | |
172 | /// normalization attempt may cause compiler bugs. | |
dfeec247 XL |
173 | pub fn struct_tail_erasing_lifetimes( |
174 | self, | |
175 | ty: Ty<'tcx>, | |
176 | param_env: ty::ParamEnv<'tcx>, | |
177 | ) -> Ty<'tcx> { | |
416331ca XL |
178 | let tcx = self; |
179 | tcx.struct_tail_with_normalize(ty, |ty| tcx.normalize_erasing_regions(param_env, ty)) | |
180 | } | |
181 | ||
182 | /// Returns the deeply last field of nested structures, or the same type if | |
183 | /// not a structure at all. Corresponds to the only possible unsized field, | |
184 | /// and its type can be used to determine unsizing strategy. | |
185 | /// | |
186 | /// This is parameterized over the normalization strategy (i.e. how to | |
187 | /// handle `<T as Trait>::Assoc` and `impl Trait`); pass the identity | |
188 | /// function to indicate no normalization should take place. | |
189 | /// | |
190 | /// See also `struct_tail_erasing_lifetimes`, which is suitable for use | |
191 | /// during codegen. | |
dfeec247 XL |
192 | pub fn struct_tail_with_normalize( |
193 | self, | |
194 | mut ty: Ty<'tcx>, | |
195 | normalize: impl Fn(Ty<'tcx>) -> Ty<'tcx>, | |
196 | ) -> Ty<'tcx> { | |
136023e0 | 197 | let recursion_limit = self.recursion_limit(); |
fc512014 | 198 | for iteration in 0.. { |
136023e0 | 199 | if !recursion_limit.value_within_limit(iteration) { |
fc512014 XL |
200 | return self.ty_error_with_message( |
201 | DUMMY_SP, | |
202 | &format!("reached the recursion limit finding the struct tail for {}", ty), | |
203 | ); | |
204 | } | |
1b1a35ee | 205 | match *ty.kind() { |
b7449926 | 206 | ty::Adt(def, substs) => { |
7cac9316 XL |
207 | if !def.is_struct() { |
208 | break; | |
209 | } | |
2c00a5a8 | 210 | match def.non_enum_variant().fields.last() { |
7cac9316 XL |
211 | Some(f) => ty = f.ty(self, substs), |
212 | None => break, | |
213 | } | |
214 | } | |
215 | ||
94222f64 XL |
216 | ty::Tuple(tys) if let Some((&last_ty, _)) = tys.split_last() => { |
217 | ty = last_ty.expect_ty(); | |
7cac9316 XL |
218 | } |
219 | ||
94222f64 XL |
220 | ty::Tuple(_) => break, |
221 | ||
416331ca XL |
222 | ty::Projection(_) | ty::Opaque(..) => { |
223 | let normalized = normalize(ty); | |
224 | if ty == normalized { | |
225 | return ty; | |
226 | } else { | |
227 | ty = normalized; | |
228 | } | |
229 | } | |
230 | ||
7cac9316 XL |
231 | _ => { |
232 | break; | |
233 | } | |
e9174d1e SL |
234 | } |
235 | } | |
236 | ty | |
237 | } | |
238 | ||
60c5eb7d | 239 | /// Same as applying `struct_tail` on `source` and `target`, but only |
e9174d1e SL |
240 | /// keeps going as long as the two types are instances of the same |
241 | /// structure definitions. | |
a1dfa0c6 | 242 | /// For `(Foo<Foo<T>>, Foo<dyn Trait>)`, the result will be `(Foo<T>, Trait)`, |
e9174d1e | 243 | /// whereas struct_tail produces `T`, and `Trait`, respectively. |
416331ca XL |
244 | /// |
245 | /// Should only be called if the types have no inference variables and do | |
60c5eb7d | 246 | /// not need their lifetimes preserved (e.g., as part of codegen); otherwise, |
416331ca | 247 | /// normalization attempt may cause compiler bugs. |
dfeec247 XL |
248 | pub fn struct_lockstep_tails_erasing_lifetimes( |
249 | self, | |
250 | source: Ty<'tcx>, | |
251 | target: Ty<'tcx>, | |
252 | param_env: ty::ParamEnv<'tcx>, | |
253 | ) -> (Ty<'tcx>, Ty<'tcx>) { | |
416331ca | 254 | let tcx = self; |
dfeec247 XL |
255 | tcx.struct_lockstep_tails_with_normalize(source, target, |ty| { |
256 | tcx.normalize_erasing_regions(param_env, ty) | |
257 | }) | |
416331ca XL |
258 | } |
259 | ||
60c5eb7d | 260 | /// Same as applying `struct_tail` on `source` and `target`, but only |
416331ca XL |
261 | /// keeps going as long as the two types are instances of the same |
262 | /// structure definitions. | |
263 | /// For `(Foo<Foo<T>>, Foo<dyn Trait>)`, the result will be `(Foo<T>, Trait)`, | |
264 | /// whereas struct_tail produces `T`, and `Trait`, respectively. | |
265 | /// | |
266 | /// See also `struct_lockstep_tails_erasing_lifetimes`, which is suitable for use | |
267 | /// during codegen. | |
dfeec247 XL |
268 | pub fn struct_lockstep_tails_with_normalize( |
269 | self, | |
270 | source: Ty<'tcx>, | |
271 | target: Ty<'tcx>, | |
272 | normalize: impl Fn(Ty<'tcx>) -> Ty<'tcx>, | |
273 | ) -> (Ty<'tcx>, Ty<'tcx>) { | |
e9174d1e | 274 | let (mut a, mut b) = (source, target); |
041b39d2 | 275 | loop { |
1b1a35ee | 276 | match (&a.kind(), &b.kind()) { |
b7449926 | 277 | (&Adt(a_def, a_substs), &Adt(b_def, b_substs)) |
dfeec247 XL |
278 | if a_def == b_def && a_def.is_struct() => |
279 | { | |
2c00a5a8 | 280 | if let Some(f) = a_def.non_enum_variant().fields.last() { |
041b39d2 XL |
281 | a = f.ty(self, a_substs); |
282 | b = f.ty(self, b_substs); | |
283 | } else { | |
284 | break; | |
285 | } | |
dfeec247 XL |
286 | } |
287 | (&Tuple(a_tys), &Tuple(b_tys)) if a_tys.len() == b_tys.len() => { | |
041b39d2 | 288 | if let Some(a_last) = a_tys.last() { |
48663c56 XL |
289 | a = a_last.expect_ty(); |
290 | b = b_tys.last().unwrap().expect_ty(); | |
041b39d2 XL |
291 | } else { |
292 | break; | |
293 | } | |
dfeec247 | 294 | } |
ba9703b0 XL |
295 | (ty::Projection(_) | ty::Opaque(..), _) |
296 | | (_, ty::Projection(_) | ty::Opaque(..)) => { | |
416331ca XL |
297 | // If either side is a projection, attempt to |
298 | // progress via normalization. (Should be safe to | |
299 | // apply to both sides as normalization is | |
300 | // idempotent.) | |
301 | let a_norm = normalize(a); | |
302 | let b_norm = normalize(b); | |
303 | if a == a_norm && b == b_norm { | |
304 | break; | |
305 | } else { | |
306 | a = a_norm; | |
307 | b = b_norm; | |
308 | } | |
309 | } | |
310 | ||
cc61c64b | 311 | _ => break, |
e9174d1e SL |
312 | } |
313 | } | |
314 | (a, b) | |
315 | } | |
316 | ||
8bb4bdeb XL |
317 | /// Calculate the destructor of a given type. |
318 | pub fn calculate_dtor( | |
319 | self, | |
320 | adt_did: DefId, | |
29967ef6 | 321 | validate: impl Fn(Self, DefId) -> Result<(), ErrorReported>, |
8bb4bdeb | 322 | ) -> Option<ty::Destructor> { |
ba9703b0 | 323 | let drop_trait = self.lang_items().drop_trait()?; |
9fa01778 | 324 | self.ensure().coherent_trait(drop_trait); |
8bb4bdeb | 325 | |
7cac9316 | 326 | let ty = self.type_of(adt_did); |
c295e0f8 | 327 | let (did, constness) = self.find_map_relevant_impl(drop_trait, ty, |impl_did| { |
3c0e092e | 328 | if let Some(item_id) = self.associated_item_def_ids(impl_did).first() { |
0bf4aa26 | 329 | if validate(self, impl_did).is_ok() { |
3c0e092e | 330 | return Some((*item_id, self.impl_constness(impl_did))); |
8bb4bdeb XL |
331 | } |
332 | } | |
29967ef6 | 333 | None |
c295e0f8 | 334 | })?; |
8bb4bdeb | 335 | |
c295e0f8 | 336 | Some(ty::Destructor { did, constness }) |
cc61c64b XL |
337 | } |
338 | ||
9fa01778 | 339 | /// Returns the set of types that are required to be alive in |
cc61c64b XL |
340 | /// order to run the destructor of `def` (see RFCs 769 and |
341 | /// 1238). | |
342 | /// | |
343 | /// Note that this returns only the constraints for the | |
344 | /// destructor of `def` itself. For the destructors of the | |
345 | /// contents, you need `adt_dtorck_constraint`. | |
dfeec247 | 346 | pub fn destructor_constraints(self, def: &'tcx ty::AdtDef) -> Vec<ty::subst::GenericArg<'tcx>> { |
cc61c64b XL |
347 | let dtor = match def.destructor(self) { |
348 | None => { | |
349 | debug!("destructor_constraints({:?}) - no dtor", def.did); | |
dfeec247 | 350 | return vec![]; |
cc61c64b | 351 | } |
dfeec247 | 352 | Some(dtor) => dtor.did, |
e9174d1e | 353 | }; |
b039eaaf | 354 | |
cc61c64b | 355 | let impl_def_id = self.associated_item(dtor).container.id(); |
7cac9316 | 356 | let impl_generics = self.generics_of(impl_def_id); |
cc61c64b XL |
357 | |
358 | // We have a destructor - all the parameters that are not | |
359 | // pure_wrt_drop (i.e, don't have a #[may_dangle] attribute) | |
360 | // must be live. | |
361 | ||
362 | // We need to return the list of parameters from the ADTs | |
363 | // generics/substs that correspond to impure parameters on the | |
364 | // impl's generics. This is a bit ugly, but conceptually simple: | |
365 | // | |
366 | // Suppose our ADT looks like the following | |
367 | // | |
368 | // struct S<X, Y, Z>(X, Y, Z); | |
369 | // | |
370 | // and the impl is | |
371 | // | |
372 | // impl<#[may_dangle] P0, P1, P2> Drop for S<P1, P2, P0> | |
373 | // | |
374 | // We want to return the parameters (X, Y). For that, we match | |
375 | // up the item-substs <X, Y, Z> with the substs on the impl ADT, | |
376 | // <P1, P2, P0>, and then look up which of the impl substs refer to | |
377 | // parameters marked as pure. | |
378 | ||
1b1a35ee | 379 | let impl_substs = match *self.type_of(impl_def_id).kind() { |
b7449926 | 380 | ty::Adt(def_, substs) if def_ == def => substs, |
dfeec247 | 381 | _ => bug!(), |
cc61c64b XL |
382 | }; |
383 | ||
1b1a35ee | 384 | let item_substs = match *self.type_of(def.did).kind() { |
b7449926 | 385 | ty::Adt(def_, substs) if def_ == def => substs, |
dfeec247 | 386 | _ => bug!(), |
cc61c64b XL |
387 | }; |
388 | ||
cdc7bbd5 | 389 | let result = iter::zip(item_substs, impl_substs) |
f9f354fc | 390 | .filter(|&(_, k)| { |
0531ce1d | 391 | match k.unpack() { |
e74abb32 | 392 | GenericArgKind::Lifetime(&ty::RegionKind::ReEarlyBound(ref ebr)) => { |
0531ce1d XL |
393 | !impl_generics.region_param(ebr, self).pure_wrt_drop |
394 | } | |
dfeec247 | 395 | GenericArgKind::Type(&ty::TyS { kind: ty::Param(ref pt), .. }) => { |
0531ce1d XL |
396 | !impl_generics.type_param(pt, self).pure_wrt_drop |
397 | } | |
e74abb32 | 398 | GenericArgKind::Const(&ty::Const { |
dfeec247 XL |
399 | val: ty::ConstKind::Param(ref pc), .. |
400 | }) => !impl_generics.const_param(pc, self).pure_wrt_drop, | |
401 | GenericArgKind::Lifetime(_) | |
402 | | GenericArgKind::Type(_) | |
403 | | GenericArgKind::Const(_) => { | |
532ac7d7 | 404 | // Not a type, const or region param: this should be reported |
0531ce1d XL |
405 | // as an error. |
406 | false | |
407 | } | |
cc61c64b | 408 | } |
0bf4aa26 | 409 | }) |
f9f354fc | 410 | .map(|(item_param, _)| item_param) |
0bf4aa26 | 411 | .collect(); |
cc61c64b XL |
412 | debug!("destructor_constraint({:?}) = {:?}", def.did, result); |
413 | result | |
b039eaaf | 414 | } |
9e0c209e | 415 | |
9fa01778 XL |
416 | /// Returns `true` if `def_id` refers to a closure (e.g., `|x| x * 2`). Note |
417 | /// that closures have a `DefId`, but the closure *expression* also | |
8faf50e0 XL |
418 | /// has a `HirId` that is located within the context where the |
419 | /// closure appears (and, sadly, a corresponding `NodeId`, since | |
420 | /// those are not yet phased out). The parent of the closure's | |
9fa01778 | 421 | /// `DefId` will also be the context where it appears. |
abe05a73 | 422 | pub fn is_closure(self, def_id: DefId) -> bool { |
f9f354fc | 423 | matches!(self.def_kind(def_id), DefKind::Closure | DefKind::Generator) |
abe05a73 XL |
424 | } |
425 | ||
3c0e092e XL |
426 | /// Returns `true` if `def_id` refers to a definition that does not have its own |
427 | /// type-checking context, i.e. closure, generator or inline const. | |
428 | pub fn is_typeck_child(self, def_id: DefId) -> bool { | |
429 | matches!( | |
430 | self.def_kind(def_id), | |
431 | DefKind::Closure | DefKind::Generator | DefKind::InlineConst | |
432 | ) | |
433 | } | |
434 | ||
9fa01778 | 435 | /// Returns `true` if `def_id` refers to a trait (i.e., `trait Foo { ... }`). |
8faf50e0 | 436 | pub fn is_trait(self, def_id: DefId) -> bool { |
f9f354fc | 437 | self.def_kind(def_id) == DefKind::Trait |
8faf50e0 XL |
438 | } |
439 | ||
9fa01778 XL |
440 | /// Returns `true` if `def_id` refers to a trait alias (i.e., `trait Foo = ...;`), |
441 | /// and `false` otherwise. | |
442 | pub fn is_trait_alias(self, def_id: DefId) -> bool { | |
f9f354fc | 443 | self.def_kind(def_id) == DefKind::TraitAlias |
9fa01778 XL |
444 | } |
445 | ||
446 | /// Returns `true` if this `DefId` refers to the implicit constructor for | |
447 | /// a tuple struct like `struct Foo(u32)`, and `false` otherwise. | |
532ac7d7 | 448 | pub fn is_constructor(self, def_id: DefId) -> bool { |
f9f354fc | 449 | matches!(self.def_kind(def_id), DefKind::Ctor(..)) |
8faf50e0 XL |
450 | } |
451 | ||
3c0e092e XL |
452 | /// Given the `DefId`, returns the `DefId` of the innermost item that |
453 | /// has its own type-checking context or "inference enviornment". | |
454 | /// | |
455 | /// For example, a closure has its own `DefId`, but it is type-checked | |
456 | /// with the containing item. Similarly, an inline const block has its | |
457 | /// own `DefId` but it is type-checked together with the containing item. | |
458 | /// | |
459 | /// Therefore, when we fetch the | |
3dfed10e XL |
460 | /// `typeck` the closure, for example, we really wind up |
461 | /// fetching the `typeck` the enclosing fn item. | |
3c0e092e | 462 | pub fn typeck_root_def_id(self, def_id: DefId) -> DefId { |
476ff2be | 463 | let mut def_id = def_id; |
3c0e092e | 464 | while self.is_typeck_child(def_id) { |
532ac7d7 | 465 | def_id = self.parent(def_id).unwrap_or_else(|| { |
476ff2be SL |
466 | bug!("closure {:?} has no parent", def_id); |
467 | }); | |
468 | } | |
469 | def_id | |
9e0c209e | 470 | } |
cc61c64b | 471 | |
9fa01778 | 472 | /// Given the `DefId` and substs a closure, creates the type of |
ff7c6d11 XL |
473 | /// `self` argument that the closure expects. For example, for a |
474 | /// `Fn` closure, this would return a reference type `&T` where | |
9fa01778 | 475 | /// `T = closure_ty`. |
ff7c6d11 XL |
476 | /// |
477 | /// Returns `None` if this closure's kind has not yet been inferred. | |
478 | /// This should only be possible during type checking. | |
479 | /// | |
480 | /// Note that the return value is a late-bound region and hence | |
481 | /// wrapped in a binder. | |
dfeec247 XL |
482 | pub fn closure_env_ty( |
483 | self, | |
484 | closure_def_id: DefId, | |
485 | closure_substs: SubstsRef<'tcx>, | |
cdc7bbd5 XL |
486 | env_region: ty::RegionKind, |
487 | ) -> Option<Ty<'tcx>> { | |
ff7c6d11 | 488 | let closure_ty = self.mk_closure(closure_def_id, closure_substs); |
ba9703b0 | 489 | let closure_kind_ty = closure_substs.as_closure().kind_ty(); |
ff7c6d11 XL |
490 | let closure_kind = closure_kind_ty.to_opt_closure_kind()?; |
491 | let env_ty = match closure_kind { | |
492 | ty::ClosureKind::Fn => self.mk_imm_ref(self.mk_region(env_region), closure_ty), | |
493 | ty::ClosureKind::FnMut => self.mk_mut_ref(self.mk_region(env_region), closure_ty), | |
494 | ty::ClosureKind::FnOnce => closure_ty, | |
495 | }; | |
cdc7bbd5 | 496 | Some(env_ty) |
ff7c6d11 XL |
497 | } |
498 | ||
48663c56 | 499 | /// Returns `true` if the node pointed to by `def_id` is a `static` item. |
1b1a35ee | 500 | pub fn is_static(self, def_id: DefId) -> bool { |
48663c56 XL |
501 | self.static_mutability(def_id).is_some() |
502 | } | |
503 | ||
f9f354fc | 504 | /// Returns `true` if this is a `static` item with the `#[thread_local]` attribute. |
1b1a35ee | 505 | pub fn is_thread_local_static(self, def_id: DefId) -> bool { |
f9f354fc XL |
506 | self.codegen_fn_attrs(def_id).flags.contains(CodegenFnAttrFlags::THREAD_LOCAL) |
507 | } | |
508 | ||
48663c56 | 509 | /// Returns `true` if the node pointed to by `def_id` is a mutable `static` item. |
1b1a35ee | 510 | pub fn is_mutable_static(self, def_id: DefId) -> bool { |
dfeec247 | 511 | self.static_mutability(def_id) == Some(hir::Mutability::Mut) |
60c5eb7d XL |
512 | } |
513 | ||
514 | /// Get the type of the pointer to the static that we use in MIR. | |
1b1a35ee | 515 | pub fn static_ptr_ty(self, def_id: DefId) -> Ty<'tcx> { |
60c5eb7d | 516 | // Make sure that any constants in the static's type are evaluated. |
dfeec247 | 517 | let static_ty = self.normalize_erasing_regions(ty::ParamEnv::empty(), self.type_of(def_id)); |
60c5eb7d | 518 | |
29967ef6 XL |
519 | // Make sure that accesses to unsafe statics end up using raw pointers. |
520 | // For thread-locals, this needs to be kept in sync with `Rvalue::ty`. | |
60c5eb7d XL |
521 | if self.is_mutable_static(def_id) { |
522 | self.mk_mut_ptr(static_ty) | |
29967ef6 XL |
523 | } else if self.is_foreign_item(def_id) { |
524 | self.mk_imm_ptr(static_ty) | |
60c5eb7d XL |
525 | } else { |
526 | self.mk_imm_ref(self.lifetimes.re_erased, static_ty) | |
527 | } | |
abe05a73 | 528 | } |
0731742a XL |
529 | |
530 | /// Expands the given impl trait type, stopping if the type is recursive. | |
c295e0f8 | 531 | #[instrument(skip(self), level = "debug")] |
0731742a XL |
532 | pub fn try_expand_impl_trait_type( |
533 | self, | |
534 | def_id: DefId, | |
532ac7d7 | 535 | substs: SubstsRef<'tcx>, |
0731742a | 536 | ) -> Result<Ty<'tcx>, Ty<'tcx>> { |
0731742a XL |
537 | let mut visitor = OpaqueTypeExpander { |
538 | seen_opaque_tys: FxHashSet::default(), | |
e1599b0c | 539 | expanded_cache: FxHashMap::default(), |
3dfed10e | 540 | primary_def_id: Some(def_id), |
0731742a | 541 | found_recursion: false, |
94222f64 | 542 | found_any_recursion: false, |
3dfed10e | 543 | check_recursion: true, |
0731742a XL |
544 | tcx: self, |
545 | }; | |
3dfed10e | 546 | |
0731742a | 547 | let expanded_type = visitor.expand_opaque_ty(def_id, substs).unwrap(); |
c295e0f8 | 548 | trace!(?expanded_type); |
dfeec247 | 549 | if visitor.found_recursion { Err(expanded_type) } else { Ok(expanded_type) } |
0731742a | 550 | } |
9e0c209e SL |
551 | } |
552 | ||
3dfed10e XL |
553 | struct OpaqueTypeExpander<'tcx> { |
554 | // Contains the DefIds of the opaque types that are currently being | |
555 | // expanded. When we expand an opaque type we insert the DefId of | |
556 | // that type, and when we finish expanding that type we remove the | |
557 | // its DefId. | |
558 | seen_opaque_tys: FxHashSet<DefId>, | |
559 | // Cache of all expansions we've seen so far. This is a critical | |
560 | // optimization for some large types produced by async fn trees. | |
561 | expanded_cache: FxHashMap<(DefId, SubstsRef<'tcx>), Ty<'tcx>>, | |
562 | primary_def_id: Option<DefId>, | |
563 | found_recursion: bool, | |
94222f64 | 564 | found_any_recursion: bool, |
3dfed10e XL |
565 | /// Whether or not to check for recursive opaque types. |
566 | /// This is `true` when we're explicitly checking for opaque type | |
567 | /// recursion, and 'false' otherwise to avoid unnecessary work. | |
568 | check_recursion: bool, | |
569 | tcx: TyCtxt<'tcx>, | |
570 | } | |
571 | ||
572 | impl<'tcx> OpaqueTypeExpander<'tcx> { | |
573 | fn expand_opaque_ty(&mut self, def_id: DefId, substs: SubstsRef<'tcx>) -> Option<Ty<'tcx>> { | |
94222f64 | 574 | if self.found_any_recursion { |
3dfed10e XL |
575 | return None; |
576 | } | |
577 | let substs = substs.fold_with(self); | |
578 | if !self.check_recursion || self.seen_opaque_tys.insert(def_id) { | |
579 | let expanded_ty = match self.expanded_cache.get(&(def_id, substs)) { | |
580 | Some(expanded_ty) => expanded_ty, | |
581 | None => { | |
582 | let generic_ty = self.tcx.type_of(def_id); | |
583 | let concrete_ty = generic_ty.subst(self.tcx, substs); | |
584 | let expanded_ty = self.fold_ty(concrete_ty); | |
585 | self.expanded_cache.insert((def_id, substs), expanded_ty); | |
586 | expanded_ty | |
587 | } | |
588 | }; | |
589 | if self.check_recursion { | |
590 | self.seen_opaque_tys.remove(&def_id); | |
591 | } | |
592 | Some(expanded_ty) | |
593 | } else { | |
594 | // If another opaque type that we contain is recursive, then it | |
595 | // will report the error, so we don't have to. | |
94222f64 | 596 | self.found_any_recursion = true; |
3dfed10e XL |
597 | self.found_recursion = def_id == *self.primary_def_id.as_ref().unwrap(); |
598 | None | |
599 | } | |
600 | } | |
601 | } | |
602 | ||
603 | impl<'tcx> TypeFolder<'tcx> for OpaqueTypeExpander<'tcx> { | |
604 | fn tcx(&self) -> TyCtxt<'tcx> { | |
605 | self.tcx | |
606 | } | |
607 | ||
608 | fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> { | |
609 | if let ty::Opaque(def_id, substs) = t.kind { | |
610 | self.expand_opaque_ty(def_id, substs).unwrap_or(t) | |
611 | } else if t.has_opaque_types() { | |
612 | t.super_fold_with(self) | |
613 | } else { | |
614 | t | |
615 | } | |
616 | } | |
617 | } | |
618 | ||
dc9dc135 | 619 | impl<'tcx> ty::TyS<'tcx> { |
dfeec247 XL |
620 | /// Returns the maximum value for the given numeric type (including `char`s) |
621 | /// or returns `None` if the type is not numeric. | |
622 | pub fn numeric_max_val(&'tcx self, tcx: TyCtxt<'tcx>) -> Option<&'tcx ty::Const<'tcx>> { | |
1b1a35ee | 623 | let val = match self.kind() { |
dfeec247 XL |
624 | ty::Int(_) | ty::Uint(_) => { |
625 | let (size, signed) = int_size_and_signed(tcx, self); | |
c295e0f8 XL |
626 | let val = |
627 | if signed { size.signed_int_max() as u128 } else { size.unsigned_int_max() }; | |
dfeec247 XL |
628 | Some(val) |
629 | } | |
630 | ty::Char => Some(std::char::MAX as u128), | |
631 | ty::Float(fty) => Some(match fty { | |
5869c6ff XL |
632 | ty::FloatTy::F32 => rustc_apfloat::ieee::Single::INFINITY.to_bits(), |
633 | ty::FloatTy::F64 => rustc_apfloat::ieee::Double::INFINITY.to_bits(), | |
dfeec247 XL |
634 | }), |
635 | _ => None, | |
636 | }; | |
637 | val.map(|v| ty::Const::from_bits(tcx, v, ty::ParamEnv::empty().and(self))) | |
638 | } | |
639 | ||
640 | /// Returns the minimum value for the given numeric type (including `char`s) | |
641 | /// or returns `None` if the type is not numeric. | |
642 | pub fn numeric_min_val(&'tcx self, tcx: TyCtxt<'tcx>) -> Option<&'tcx ty::Const<'tcx>> { | |
1b1a35ee | 643 | let val = match self.kind() { |
dfeec247 XL |
644 | ty::Int(_) | ty::Uint(_) => { |
645 | let (size, signed) = int_size_and_signed(tcx, self); | |
c295e0f8 | 646 | let val = if signed { size.truncate(size.signed_int_min() as u128) } else { 0 }; |
dfeec247 XL |
647 | Some(val) |
648 | } | |
649 | ty::Char => Some(0), | |
650 | ty::Float(fty) => Some(match fty { | |
5869c6ff XL |
651 | ty::FloatTy::F32 => (-::rustc_apfloat::ieee::Single::INFINITY).to_bits(), |
652 | ty::FloatTy::F64 => (-::rustc_apfloat::ieee::Double::INFINITY).to_bits(), | |
dfeec247 XL |
653 | }), |
654 | _ => None, | |
655 | }; | |
656 | val.map(|v| ty::Const::from_bits(tcx, v, ty::ParamEnv::empty().and(self))) | |
657 | } | |
658 | ||
0731742a XL |
659 | /// Checks whether values of this type `T` are *moved* or *copied* |
660 | /// when referenced -- this amounts to a check for whether `T: | |
661 | /// Copy`, but note that we **don't** consider lifetimes when | |
662 | /// doing this check. This means that we may generate MIR which | |
663 | /// does copies even when the type actually doesn't satisfy the | |
664 | /// full requirements for the `Copy` trait (cc #29149) -- this | |
665 | /// winds up being reported as an error during NLL borrow check. | |
dc9dc135 XL |
666 | pub fn is_copy_modulo_regions( |
667 | &'tcx self, | |
f035d41b | 668 | tcx_at: TyCtxtAt<'tcx>, |
dc9dc135 | 669 | param_env: ty::ParamEnv<'tcx>, |
dc9dc135 | 670 | ) -> bool { |
f035d41b | 671 | tcx_at.is_copy_raw(param_env.and(self)) |
e9174d1e SL |
672 | } |
673 | ||
0731742a XL |
674 | /// Checks whether values of this type `T` have a size known at |
675 | /// compile time (i.e., whether `T: Sized`). Lifetimes are ignored | |
676 | /// for the purposes of this check, so it can be an | |
677 | /// over-approximation in generic contexts, where one can have | |
678 | /// strange rules like `<T as Foo<'static>>::Bar: Sized` that | |
679 | /// actually carry lifetime requirements. | |
dc9dc135 | 680 | pub fn is_sized(&'tcx self, tcx_at: TyCtxtAt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> bool { |
74b04a01 | 681 | self.is_trivially_sized(tcx_at.tcx) || tcx_at.is_sized_raw(param_env.and(self)) |
e9174d1e SL |
682 | } |
683 | ||
0731742a | 684 | /// Checks whether values of this type `T` implement the `Freeze` |
94222f64 | 685 | /// trait -- frozen types are those that do not contain an |
9fa01778 | 686 | /// `UnsafeCell` anywhere. This is a language concept used to |
0731742a XL |
687 | /// distinguish "true immutability", which is relevant to |
688 | /// optimization as well as the rules around static values. Note | |
689 | /// that the `Freeze` trait is not exposed to end users and is | |
690 | /// effectively an implementation detail. | |
f035d41b XL |
691 | pub fn is_freeze(&'tcx self, tcx_at: TyCtxtAt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> bool { |
692 | self.is_trivially_freeze() || tcx_at.is_freeze_raw(param_env.and(self)) | |
74b04a01 XL |
693 | } |
694 | ||
695 | /// Fast path helper for testing if a type is `Freeze`. | |
696 | /// | |
697 | /// Returning true means the type is known to be `Freeze`. Returning | |
698 | /// `false` means nothing -- could be `Freeze`, might not be. | |
699 | fn is_trivially_freeze(&self) -> bool { | |
1b1a35ee | 700 | match self.kind() { |
74b04a01 XL |
701 | ty::Int(_) |
702 | | ty::Uint(_) | |
703 | | ty::Float(_) | |
704 | | ty::Bool | |
705 | | ty::Char | |
706 | | ty::Str | |
707 | | ty::Never | |
708 | | ty::Ref(..) | |
709 | | ty::RawPtr(_) | |
710 | | ty::FnDef(..) | |
f035d41b | 711 | | ty::Error(_) |
74b04a01 XL |
712 | | ty::FnPtr(_) => true, |
713 | ty::Tuple(_) => self.tuple_fields().all(Self::is_trivially_freeze), | |
714 | ty::Slice(elem_ty) | ty::Array(elem_ty, _) => elem_ty.is_trivially_freeze(), | |
715 | ty::Adt(..) | |
716 | | ty::Bound(..) | |
717 | | ty::Closure(..) | |
718 | | ty::Dynamic(..) | |
719 | | ty::Foreign(_) | |
720 | | ty::Generator(..) | |
721 | | ty::GeneratorWitness(_) | |
722 | | ty::Infer(_) | |
723 | | ty::Opaque(..) | |
724 | | ty::Param(_) | |
725 | | ty::Placeholder(_) | |
f9f354fc | 726 | | ty::Projection(_) => false, |
74b04a01 | 727 | } |
cc61c64b XL |
728 | } |
729 | ||
cdc7bbd5 XL |
730 | /// Checks whether values of this type `T` implement the `Unpin` trait. |
731 | pub fn is_unpin(&'tcx self, tcx_at: TyCtxtAt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> bool { | |
732 | self.is_trivially_unpin() || tcx_at.is_unpin_raw(param_env.and(self)) | |
733 | } | |
734 | ||
735 | /// Fast path helper for testing if a type is `Unpin`. | |
736 | /// | |
737 | /// Returning true means the type is known to be `Unpin`. Returning | |
738 | /// `false` means nothing -- could be `Unpin`, might not be. | |
739 | fn is_trivially_unpin(&self) -> bool { | |
740 | match self.kind() { | |
741 | ty::Int(_) | |
742 | | ty::Uint(_) | |
743 | | ty::Float(_) | |
744 | | ty::Bool | |
745 | | ty::Char | |
746 | | ty::Str | |
747 | | ty::Never | |
748 | | ty::Ref(..) | |
749 | | ty::RawPtr(_) | |
750 | | ty::FnDef(..) | |
751 | | ty::Error(_) | |
752 | | ty::FnPtr(_) => true, | |
753 | ty::Tuple(_) => self.tuple_fields().all(Self::is_trivially_unpin), | |
754 | ty::Slice(elem_ty) | ty::Array(elem_ty, _) => elem_ty.is_trivially_unpin(), | |
755 | ty::Adt(..) | |
756 | | ty::Bound(..) | |
757 | | ty::Closure(..) | |
758 | | ty::Dynamic(..) | |
759 | | ty::Foreign(_) | |
760 | | ty::Generator(..) | |
761 | | ty::GeneratorWitness(_) | |
762 | | ty::Infer(_) | |
763 | | ty::Opaque(..) | |
764 | | ty::Param(_) | |
765 | | ty::Placeholder(_) | |
766 | | ty::Projection(_) => false, | |
767 | } | |
768 | } | |
769 | ||
cc61c64b XL |
770 | /// If `ty.needs_drop(...)` returns `true`, then `ty` is definitely |
771 | /// non-copy and *might* have a destructor attached; if it returns | |
0731742a | 772 | /// `false`, then `ty` definitely has no destructor (i.e., no drop glue). |
cc61c64b XL |
773 | /// |
774 | /// (Note that this implies that if `ty` has a destructor attached, | |
775 | /// then `needs_drop` will definitely return `true` for `ty`.) | |
e74abb32 XL |
776 | /// |
777 | /// Note that this method is used to check eligible types in unions. | |
cc61c64b | 778 | #[inline] |
dc9dc135 | 779 | pub fn needs_drop(&'tcx self, tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> bool { |
74b04a01 XL |
780 | // Avoid querying in simple cases. |
781 | match needs_drop_components(self, &tcx.data_layout) { | |
782 | Err(AlwaysRequiresDrop) => true, | |
783 | Ok(components) => { | |
784 | let query_ty = match *components { | |
785 | [] => return false, | |
786 | // If we've got a single component, call the query with that | |
787 | // to increase the chance that we hit the query cache. | |
788 | [component_ty] => component_ty, | |
789 | _ => self, | |
790 | }; | |
a2a8927a | 791 | |
74b04a01 XL |
792 | // This doesn't depend on regions, so try to minimize distinct |
793 | // query keys used. | |
a2a8927a XL |
794 | // If normalization fails, we just use `query_ty`. |
795 | let query_ty = | |
796 | tcx.try_normalize_erasing_regions(param_env, query_ty).unwrap_or(query_ty); | |
797 | ||
798 | tcx.needs_drop_raw(param_env.and(query_ty)) | |
74b04a01 XL |
799 | } |
800 | } | |
cc61c64b XL |
801 | } |
802 | ||
17df50a5 XL |
803 | /// Checks if `ty` has has a significant drop. |
804 | /// | |
805 | /// Note that this method can return false even if `ty` has a destructor | |
806 | /// attached; even if that is the case then the adt has been marked with | |
807 | /// the attribute `rustc_insignificant_dtor`. | |
808 | /// | |
809 | /// Note that this method is used to check for change in drop order for | |
810 | /// 2229 drop reorder migration analysis. | |
811 | #[inline] | |
812 | pub fn has_significant_drop( | |
813 | &'tcx self, | |
814 | tcx: TyCtxt<'tcx>, | |
815 | param_env: ty::ParamEnv<'tcx>, | |
816 | ) -> bool { | |
817 | // Avoid querying in simple cases. | |
818 | match needs_drop_components(self, &tcx.data_layout) { | |
819 | Err(AlwaysRequiresDrop) => true, | |
820 | Ok(components) => { | |
821 | let query_ty = match *components { | |
822 | [] => return false, | |
823 | // If we've got a single component, call the query with that | |
824 | // to increase the chance that we hit the query cache. | |
825 | [component_ty] => component_ty, | |
826 | _ => self, | |
827 | }; | |
136023e0 XL |
828 | |
829 | // FIXME(#86868): We should be canonicalizing, or else moving this to a method of inference | |
830 | // context, or *something* like that, but for now just avoid passing inference | |
831 | // variables to queries that can't cope with them. Instead, conservatively | |
832 | // return "true" (may change drop order). | |
833 | if query_ty.needs_infer() { | |
834 | return true; | |
835 | } | |
836 | ||
17df50a5 XL |
837 | // This doesn't depend on regions, so try to minimize distinct |
838 | // query keys used. | |
839 | let erased = tcx.normalize_erasing_regions(param_env, query_ty); | |
840 | tcx.has_significant_drop_raw(param_env.and(erased)) | |
841 | } | |
842 | } | |
843 | } | |
844 | ||
f035d41b XL |
845 | /// Returns `true` if equality for this type is both reflexive and structural. |
846 | /// | |
847 | /// Reflexive equality for a type is indicated by an `Eq` impl for that type. | |
848 | /// | |
849 | /// Primitive types (`u32`, `str`) have structural equality by definition. For composite data | |
850 | /// types, equality for the type as a whole is structural when it is the same as equality | |
851 | /// between all components (fields, array elements, etc.) of that type. For ADTs, structural | |
852 | /// equality is indicated by an implementation of `PartialStructuralEq` and `StructuralEq` for | |
853 | /// that type. | |
854 | /// | |
855 | /// This function is "shallow" because it may return `true` for a composite type whose fields | |
856 | /// are not `StructuralEq`. For example, `[T; 4]` has structural equality regardless of `T` | |
857 | /// because equality for arrays is determined by the equality of each array element. If you | |
858 | /// want to know whether a given call to `PartialEq::eq` will proceed structurally all the way | |
859 | /// down, you will need to use a type visitor. | |
860 | #[inline] | |
861 | pub fn is_structural_eq_shallow(&'tcx self, tcx: TyCtxt<'tcx>) -> bool { | |
1b1a35ee | 862 | match self.kind() { |
f035d41b XL |
863 | // Look for an impl of both `PartialStructuralEq` and `StructuralEq`. |
864 | Adt(..) => tcx.has_structural_eq_impls(self), | |
865 | ||
866 | // Primitive types that satisfy `Eq`. | |
867 | Bool | Char | Int(_) | Uint(_) | Str | Never => true, | |
868 | ||
869 | // Composite types that satisfy `Eq` when all of their fields do. | |
870 | // | |
871 | // Because this function is "shallow", we return `true` for these composites regardless | |
872 | // of the type(s) contained within. | |
873 | Ref(..) | Array(..) | Slice(_) | Tuple(..) => true, | |
874 | ||
875 | // Raw pointers use bitwise comparison. | |
876 | RawPtr(_) | FnPtr(_) => true, | |
877 | ||
878 | // Floating point numbers are not `Eq`. | |
879 | Float(_) => false, | |
880 | ||
881 | // Conservatively return `false` for all others... | |
882 | ||
883 | // Anonymous function types | |
884 | FnDef(..) | Closure(..) | Dynamic(..) | Generator(..) => false, | |
885 | ||
886 | // Generic or inferred types | |
887 | // | |
888 | // FIXME(ecstaticmorse): Maybe we should `bug` here? This should probably only be | |
889 | // called for known, fully-monomorphized types. | |
890 | Projection(_) | Opaque(..) | Param(_) | Bound(..) | Placeholder(_) | Infer(_) => false, | |
891 | ||
892 | Foreign(_) | GeneratorWitness(..) | Error(_) => false, | |
893 | } | |
894 | } | |
895 | ||
0731742a | 896 | pub fn same_type(a: Ty<'tcx>, b: Ty<'tcx>) -> bool { |
1b1a35ee | 897 | match (&a.kind(), &b.kind()) { |
0731742a XL |
898 | (&Adt(did_a, substs_a), &Adt(did_b, substs_b)) => { |
899 | if did_a != did_b { | |
900 | return false; | |
901 | } | |
902 | ||
903 | substs_a.types().zip(substs_b.types()).all(|(a, b)| Self::same_type(a, b)) | |
904 | } | |
905 | _ => a == b, | |
906 | } | |
907 | } | |
908 | ||
e1599b0c XL |
909 | /// Peel off all reference types in this type until there are none left. |
910 | /// | |
911 | /// This method is idempotent, i.e. `ty.peel_refs().peel_refs() == ty.peel_refs()`. | |
912 | /// | |
913 | /// # Examples | |
914 | /// | |
915 | /// - `u8` -> `u8` | |
916 | /// - `&'a mut u8` -> `u8` | |
917 | /// - `&'a &'b u8` -> `u8` | |
918 | /// - `&'a *const &'b u8 -> *const &'b u8` | |
919 | pub fn peel_refs(&'tcx self) -> Ty<'tcx> { | |
920 | let mut ty = self; | |
1b1a35ee | 921 | while let Ref(_, inner_ty, _) = ty.kind() { |
e1599b0c XL |
922 | ty = inner_ty; |
923 | } | |
924 | ty | |
925 | } | |
136023e0 XL |
926 | |
927 | pub fn outer_exclusive_binder(&'tcx self) -> DebruijnIndex { | |
928 | self.outer_exclusive_binder | |
929 | } | |
e9174d1e | 930 | } |
7cac9316 | 931 | |
abe05a73 XL |
932 | pub enum ExplicitSelf<'tcx> { |
933 | ByValue, | |
934 | ByReference(ty::Region<'tcx>, hir::Mutability), | |
ff7c6d11 | 935 | ByRawPointer(hir::Mutability), |
abe05a73 | 936 | ByBox, |
dfeec247 | 937 | Other, |
abe05a73 XL |
938 | } |
939 | ||
940 | impl<'tcx> ExplicitSelf<'tcx> { | |
941 | /// Categorizes an explicit self declaration like `self: SomeType` | |
942 | /// into either `self`, `&self`, `&mut self`, `Box<self>`, or | |
943 | /// `Other`. | |
944 | /// This is mainly used to require the arbitrary_self_types feature | |
945 | /// in the case of `Other`, to improve error messages in the common cases, | |
946 | /// and to make `Other` non-object-safe. | |
947 | /// | |
948 | /// Examples: | |
949 | /// | |
950 | /// ``` | |
951 | /// impl<'a> Foo for &'a T { | |
952 | /// // Legal declarations: | |
953 | /// fn method1(self: &&'a T); // ExplicitSelf::ByReference | |
954 | /// fn method2(self: &'a T); // ExplicitSelf::ByValue | |
955 | /// fn method3(self: Box<&'a T>); // ExplicitSelf::ByBox | |
956 | /// fn method4(self: Rc<&'a T>); // ExplicitSelf::Other | |
957 | /// | |
958 | /// // Invalid cases will be caught by `check_method_receiver`: | |
959 | /// fn method_err1(self: &'a mut T); // ExplicitSelf::Other | |
960 | /// fn method_err2(self: &'static T) // ExplicitSelf::ByValue | |
961 | /// fn method_err3(self: &&T) // ExplicitSelf::ByReference | |
962 | /// } | |
963 | /// ``` | |
964 | /// | |
dfeec247 | 965 | pub fn determine<P>(self_arg_ty: Ty<'tcx>, is_self_ty: P) -> ExplicitSelf<'tcx> |
abe05a73 | 966 | where |
dfeec247 | 967 | P: Fn(Ty<'tcx>) -> bool, |
abe05a73 XL |
968 | { |
969 | use self::ExplicitSelf::*; | |
970 | ||
1b1a35ee | 971 | match *self_arg_ty.kind() { |
abe05a73 | 972 | _ if is_self_ty(self_arg_ty) => ByValue, |
dfeec247 XL |
973 | ty::Ref(region, ty, mutbl) if is_self_ty(ty) => ByReference(region, mutbl), |
974 | ty::RawPtr(ty::TypeAndMut { ty, mutbl }) if is_self_ty(ty) => ByRawPointer(mutbl), | |
975 | ty::Adt(def, _) if def.is_box() && is_self_ty(self_arg_ty.boxed_ty()) => ByBox, | |
976 | _ => Other, | |
abe05a73 XL |
977 | } |
978 | } | |
979 | } | |
74b04a01 XL |
980 | |
981 | /// Returns a list of types such that the given type needs drop if and only if | |
982 | /// *any* of the returned types need drop. Returns `Err(AlwaysRequiresDrop)` if | |
983 | /// this type always needs drop. | |
a2a8927a | 984 | pub fn needs_drop_components<'tcx>( |
74b04a01 XL |
985 | ty: Ty<'tcx>, |
986 | target_layout: &TargetDataLayout, | |
987 | ) -> Result<SmallVec<[Ty<'tcx>; 2]>, AlwaysRequiresDrop> { | |
1b1a35ee | 988 | match ty.kind() { |
74b04a01 XL |
989 | ty::Infer(ty::FreshIntTy(_)) |
990 | | ty::Infer(ty::FreshFloatTy(_)) | |
991 | | ty::Bool | |
992 | | ty::Int(_) | |
993 | | ty::Uint(_) | |
994 | | ty::Float(_) | |
995 | | ty::Never | |
996 | | ty::FnDef(..) | |
997 | | ty::FnPtr(_) | |
998 | | ty::Char | |
999 | | ty::GeneratorWitness(..) | |
1000 | | ty::RawPtr(_) | |
1001 | | ty::Ref(..) | |
1002 | | ty::Str => Ok(SmallVec::new()), | |
1003 | ||
1004 | // Foreign types can never have destructors. | |
1005 | ty::Foreign(..) => Ok(SmallVec::new()), | |
1006 | ||
f035d41b | 1007 | ty::Dynamic(..) | ty::Error(_) => Err(AlwaysRequiresDrop), |
74b04a01 XL |
1008 | |
1009 | ty::Slice(ty) => needs_drop_components(ty, target_layout), | |
1010 | ty::Array(elem_ty, size) => { | |
1011 | match needs_drop_components(elem_ty, target_layout) { | |
1012 | Ok(v) if v.is_empty() => Ok(v), | |
1013 | res => match size.val.try_to_bits(target_layout.pointer_size) { | |
1014 | // Arrays of size zero don't need drop, even if their element | |
1015 | // type does. | |
1016 | Some(0) => Ok(SmallVec::new()), | |
1017 | Some(_) => res, | |
1018 | // We don't know which of the cases above we are in, so | |
1019 | // return the whole type and let the caller decide what to | |
1020 | // do. | |
1021 | None => Ok(smallvec![ty]), | |
1022 | }, | |
1023 | } | |
1024 | } | |
1025 | // If any field needs drop, then the whole tuple does. | |
1026 | ty::Tuple(..) => ty.tuple_fields().try_fold(SmallVec::new(), move |mut acc, elem| { | |
1027 | acc.extend(needs_drop_components(elem, target_layout)?); | |
1028 | Ok(acc) | |
1029 | }), | |
1030 | ||
1031 | // These require checking for `Copy` bounds or `Adt` destructors. | |
1032 | ty::Adt(..) | |
1033 | | ty::Projection(..) | |
74b04a01 XL |
1034 | | ty::Param(_) |
1035 | | ty::Bound(..) | |
1036 | | ty::Placeholder(..) | |
1037 | | ty::Opaque(..) | |
1038 | | ty::Infer(_) | |
ba9703b0 XL |
1039 | | ty::Closure(..) |
1040 | | ty::Generator(..) => Ok(smallvec![ty]), | |
74b04a01 XL |
1041 | } |
1042 | } | |
1043 | ||
fc512014 XL |
1044 | // Does the equivalent of |
1045 | // ``` | |
1046 | // let v = self.iter().map(|p| p.fold_with(folder)).collect::<SmallVec<[_; 8]>>(); | |
1047 | // folder.tcx().intern_*(&v) | |
1048 | // ``` | |
1049 | pub fn fold_list<'tcx, F, T>( | |
1050 | list: &'tcx ty::List<T>, | |
1051 | folder: &mut F, | |
1052 | intern: impl FnOnce(TyCtxt<'tcx>, &[T]) -> &'tcx ty::List<T>, | |
a2a8927a | 1053 | ) -> Result<&'tcx ty::List<T>, F::Error> |
fc512014 | 1054 | where |
a2a8927a | 1055 | F: FallibleTypeFolder<'tcx>, |
fc512014 XL |
1056 | T: TypeFoldable<'tcx> + PartialEq + Copy, |
1057 | { | |
1058 | let mut iter = list.iter(); | |
1059 | // Look for the first element that changed | |
a2a8927a XL |
1060 | match iter.by_ref().enumerate().find_map(|(i, t)| match t.try_fold_with(folder) { |
1061 | Ok(new_t) if new_t == t => None, | |
1062 | new_t => Some((i, new_t)), | |
fc512014 | 1063 | }) { |
a2a8927a XL |
1064 | Some((i, Ok(new_t))) => { |
1065 | // An element changed, prepare to intern the resulting list | |
1066 | let mut new_list = SmallVec::<[_; 8]>::with_capacity(list.len()); | |
1067 | new_list.extend_from_slice(&list[..i]); | |
1068 | new_list.push(new_t); | |
1069 | for t in iter { | |
1070 | new_list.push(t.try_fold_with(folder)?) | |
1071 | } | |
1072 | Ok(intern(folder.tcx(), &new_list)) | |
1073 | } | |
1074 | Some((_, Err(err))) => { | |
1075 | return Err(err); | |
1076 | } | |
1077 | None => Ok(list), | |
fc512014 XL |
1078 | } |
1079 | } | |
1080 | ||
3dfed10e | 1081 | #[derive(Copy, Clone, Debug, HashStable, TyEncodable, TyDecodable)] |
74b04a01 | 1082 | pub struct AlwaysRequiresDrop; |
3dfed10e XL |
1083 | |
1084 | /// Normalizes all opaque types in the given value, replacing them | |
1085 | /// with their underlying types. | |
a2a8927a | 1086 | pub fn normalize_opaque_types<'tcx>( |
3dfed10e XL |
1087 | tcx: TyCtxt<'tcx>, |
1088 | val: &'tcx List<ty::Predicate<'tcx>>, | |
1089 | ) -> &'tcx List<ty::Predicate<'tcx>> { | |
1090 | let mut visitor = OpaqueTypeExpander { | |
1091 | seen_opaque_tys: FxHashSet::default(), | |
1092 | expanded_cache: FxHashMap::default(), | |
1093 | primary_def_id: None, | |
1094 | found_recursion: false, | |
94222f64 | 1095 | found_any_recursion: false, |
3dfed10e XL |
1096 | check_recursion: false, |
1097 | tcx, | |
1098 | }; | |
1099 | val.fold_with(&mut visitor) | |
1100 | } | |
1101 | ||
1102 | pub fn provide(providers: &mut ty::query::Providers) { | |
1103 | *providers = ty::query::Providers { normalize_opaque_types, ..*providers } | |
1104 | } |