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9fa01778 XL |
1 | //! Miscellaneous type-system utilities that are too small to deserve their own modules. |
2 | ||
9fa01778 | 3 | use crate::ich::NodeIdHashingMode; |
f9f354fc | 4 | use crate::middle::codegen_fn_attrs::CodegenFnAttrFlags; |
3dfed10e | 5 | use crate::ty::fold::TypeFolder; |
ba9703b0 | 6 | use crate::ty::layout::IntegerExt; |
9fa01778 | 7 | use crate::ty::query::TyCtxtAt; |
29967ef6 | 8 | use crate::ty::subst::{GenericArgKind, Subst, SubstsRef}; |
9fa01778 | 9 | use crate::ty::TyKind::*; |
136023e0 | 10 | use crate::ty::{self, DebruijnIndex, DefIdTree, List, Ty, TyCtxt, TypeFoldable}; |
dfeec247 | 11 | use rustc_apfloat::Float as _; |
3dfed10e | 12 | use rustc_ast as ast; |
74b04a01 | 13 | use rustc_attr::{self as attr, SignedInt, UnsignedInt}; |
0731742a | 14 | use rustc_data_structures::fx::{FxHashMap, FxHashSet}; |
dfeec247 | 15 | use rustc_data_structures::stable_hasher::{HashStable, StableHasher}; |
ba9703b0 | 16 | use rustc_errors::ErrorReported; |
dfeec247 XL |
17 | use rustc_hir as hir; |
18 | use rustc_hir::def::DefKind; | |
19 | use rustc_hir::def_id::DefId; | |
532ac7d7 | 20 | use rustc_macros::HashStable; |
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 signed_min(size: Size) -> i128 { |
29967ef6 | 49 | size.sign_extend(1_u128 << (size.bits() - 1)) as i128 |
dfeec247 XL |
50 | } |
51 | ||
52 | fn signed_max(size: Size) -> i128 { | |
74b04a01 | 53 | i128::MAX >> (128 - size.bits()) |
dfeec247 XL |
54 | } |
55 | ||
56 | fn unsigned_max(size: Size) -> u128 { | |
74b04a01 | 57 | u128::MAX >> (128 - size.bits()) |
dfeec247 XL |
58 | } |
59 | ||
60 | fn int_size_and_signed<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> (Size, bool) { | |
1b1a35ee | 61 | let (int, signed) = match *ty.kind() { |
5869c6ff XL |
62 | Int(ity) => (Integer::from_int_ty(&tcx, ity), true), |
63 | Uint(uty) => (Integer::from_uint_ty(&tcx, uty), false), | |
dfeec247 XL |
64 | _ => bug!("non integer discriminant"), |
65 | }; | |
66 | (int.size(), signed) | |
67 | } | |
68 | ||
0531ce1d | 69 | impl<'tcx> Discr<'tcx> { |
9fa01778 | 70 | /// Adds `1` to the value and wraps around if the maximum for the type is reached. |
dc9dc135 | 71 | pub fn wrap_incr(self, tcx: TyCtxt<'tcx>) -> Self { |
0531ce1d XL |
72 | self.checked_add(tcx, 1).0 |
73 | } | |
dc9dc135 | 74 | pub fn checked_add(self, tcx: TyCtxt<'tcx>, n: u128) -> (Self, bool) { |
dfeec247 XL |
75 | let (size, signed) = int_size_and_signed(tcx, self.ty); |
76 | let (val, oflo) = if signed { | |
77 | let min = signed_min(size); | |
78 | let max = signed_max(size); | |
29967ef6 | 79 | let val = size.sign_extend(self.val) as i128; |
74b04a01 | 80 | assert!(n < (i128::MAX as u128)); |
0531ce1d XL |
81 | let n = n as i128; |
82 | let oflo = val > max - n; | |
dfeec247 | 83 | let val = if oflo { min + (n - (max - val) - 1) } else { val + n }; |
0531ce1d XL |
84 | // zero the upper bits |
85 | let val = val as u128; | |
29967ef6 | 86 | let val = size.truncate(val); |
dfeec247 | 87 | (val, oflo) |
0531ce1d | 88 | } else { |
dfeec247 | 89 | let max = unsigned_max(size); |
0531ce1d XL |
90 | let val = self.val; |
91 | let oflo = val > max - n; | |
dfeec247 XL |
92 | let val = if oflo { n - (max - val) - 1 } else { val + n }; |
93 | (val, oflo) | |
94 | }; | |
95 | (Self { val, ty: self.ty }, oflo) | |
8bb4bdeb | 96 | } |
e9174d1e SL |
97 | } |
98 | ||
0531ce1d | 99 | pub trait IntTypeExt { |
dc9dc135 XL |
100 | fn to_ty<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Ty<'tcx>; |
101 | fn disr_incr<'tcx>(&self, tcx: TyCtxt<'tcx>, val: Option<Discr<'tcx>>) -> Option<Discr<'tcx>>; | |
102 | fn initial_discriminant<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Discr<'tcx>; | |
0531ce1d XL |
103 | } |
104 | ||
e9174d1e | 105 | impl IntTypeExt for attr::IntType { |
dc9dc135 | 106 | fn to_ty<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> { |
e9174d1e | 107 | match *self { |
dfeec247 XL |
108 | SignedInt(ast::IntTy::I8) => tcx.types.i8, |
109 | SignedInt(ast::IntTy::I16) => tcx.types.i16, | |
110 | SignedInt(ast::IntTy::I32) => tcx.types.i32, | |
111 | SignedInt(ast::IntTy::I64) => tcx.types.i64, | |
112 | SignedInt(ast::IntTy::I128) => tcx.types.i128, | |
113 | SignedInt(ast::IntTy::Isize) => tcx.types.isize, | |
114 | UnsignedInt(ast::UintTy::U8) => tcx.types.u8, | |
115 | UnsignedInt(ast::UintTy::U16) => tcx.types.u16, | |
116 | UnsignedInt(ast::UintTy::U32) => tcx.types.u32, | |
117 | UnsignedInt(ast::UintTy::U64) => tcx.types.u64, | |
118 | UnsignedInt(ast::UintTy::U128) => tcx.types.u128, | |
2c00a5a8 | 119 | UnsignedInt(ast::UintTy::Usize) => tcx.types.usize, |
e9174d1e SL |
120 | } |
121 | } | |
122 | ||
dc9dc135 | 123 | fn initial_discriminant<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Discr<'tcx> { |
dfeec247 | 124 | Discr { val: 0, ty: self.to_ty(tcx) } |
e9174d1e SL |
125 | } |
126 | ||
dc9dc135 | 127 | fn disr_incr<'tcx>(&self, tcx: TyCtxt<'tcx>, val: Option<Discr<'tcx>>) -> Option<Discr<'tcx>> { |
a7813a04 | 128 | if let Some(val) = val { |
0531ce1d XL |
129 | assert_eq!(self.to_ty(tcx), val.ty); |
130 | let (new, oflo) = val.checked_add(tcx, 1); | |
dfeec247 | 131 | if oflo { None } else { Some(new) } |
a7813a04 XL |
132 | } else { |
133 | Some(self.initial_discriminant(tcx)) | |
134 | } | |
e9174d1e SL |
135 | } |
136 | } | |
137 | ||
dc9dc135 | 138 | impl<'tcx> TyCtxt<'tcx> { |
cc61c64b XL |
139 | /// Creates a hash of the type `Ty` which will be the same no matter what crate |
140 | /// context it's calculated within. This is used by the `type_id` intrinsic. | |
141 | pub fn type_id_hash(self, ty: Ty<'tcx>) -> u64 { | |
142 | let mut hasher = StableHasher::new(); | |
ea8adc8c | 143 | let mut hcx = self.create_stable_hashing_context(); |
cc61c64b | 144 | |
3b2f2976 XL |
145 | // We want the type_id be independent of the types free regions, so we |
146 | // erase them. The erase_regions() call will also anonymize bound | |
147 | // regions, which is desirable too. | |
fc512014 | 148 | let ty = self.erase_regions(ty); |
3b2f2976 | 149 | |
cc61c64b XL |
150 | hcx.while_hashing_spans(false, |hcx| { |
151 | hcx.with_node_id_hashing_mode(NodeIdHashingMode::HashDefPath, |hcx| { | |
152 | ty.hash_stable(hcx, &mut hasher); | |
153 | }); | |
154 | }); | |
155 | hasher.finish() | |
156 | } | |
cc61c64b | 157 | |
5bcae85e | 158 | pub fn has_error_field(self, ty: Ty<'tcx>) -> bool { |
1b1a35ee | 159 | if let ty::Adt(def, substs) = *ty.kind() { |
0bf4aa26 XL |
160 | for field in def.all_fields() { |
161 | let field_ty = field.ty(self, substs); | |
1b1a35ee | 162 | if let Error(_) = field_ty.kind() { |
0bf4aa26 | 163 | return true; |
5bcae85e SL |
164 | } |
165 | } | |
5bcae85e SL |
166 | } |
167 | false | |
168 | } | |
169 | ||
416331ca XL |
170 | /// Attempts to returns the deeply last field of nested structures, but |
171 | /// does not apply any normalization in its search. Returns the same type | |
172 | /// if input `ty` is not a structure at all. | |
dfeec247 | 173 | pub fn struct_tail_without_normalization(self, ty: Ty<'tcx>) -> Ty<'tcx> { |
416331ca XL |
174 | let tcx = self; |
175 | tcx.struct_tail_with_normalize(ty, |ty| ty) | |
176 | } | |
177 | ||
178 | /// Returns the deeply last field of nested structures, or the same type if | |
179 | /// not a structure at all. Corresponds to the only possible unsized field, | |
180 | /// and its type can be used to determine unsizing strategy. | |
181 | /// | |
182 | /// Should only be called if `ty` has no inference variables and does not | |
183 | /// need its lifetimes preserved (e.g. as part of codegen); otherwise | |
184 | /// normalization attempt may cause compiler bugs. | |
dfeec247 XL |
185 | pub fn struct_tail_erasing_lifetimes( |
186 | self, | |
187 | ty: Ty<'tcx>, | |
188 | param_env: ty::ParamEnv<'tcx>, | |
189 | ) -> Ty<'tcx> { | |
416331ca XL |
190 | let tcx = self; |
191 | tcx.struct_tail_with_normalize(ty, |ty| tcx.normalize_erasing_regions(param_env, ty)) | |
192 | } | |
193 | ||
194 | /// Returns the deeply last field of nested structures, or the same type if | |
195 | /// not a structure at all. Corresponds to the only possible unsized field, | |
196 | /// and its type can be used to determine unsizing strategy. | |
197 | /// | |
198 | /// This is parameterized over the normalization strategy (i.e. how to | |
199 | /// handle `<T as Trait>::Assoc` and `impl Trait`); pass the identity | |
200 | /// function to indicate no normalization should take place. | |
201 | /// | |
202 | /// See also `struct_tail_erasing_lifetimes`, which is suitable for use | |
203 | /// during codegen. | |
dfeec247 XL |
204 | pub fn struct_tail_with_normalize( |
205 | self, | |
206 | mut ty: Ty<'tcx>, | |
207 | normalize: impl Fn(Ty<'tcx>) -> Ty<'tcx>, | |
208 | ) -> Ty<'tcx> { | |
136023e0 | 209 | let recursion_limit = self.recursion_limit(); |
fc512014 | 210 | for iteration in 0.. { |
136023e0 | 211 | if !recursion_limit.value_within_limit(iteration) { |
fc512014 XL |
212 | return self.ty_error_with_message( |
213 | DUMMY_SP, | |
214 | &format!("reached the recursion limit finding the struct tail for {}", ty), | |
215 | ); | |
216 | } | |
1b1a35ee | 217 | match *ty.kind() { |
b7449926 | 218 | ty::Adt(def, substs) => { |
7cac9316 XL |
219 | if !def.is_struct() { |
220 | break; | |
221 | } | |
2c00a5a8 | 222 | match def.non_enum_variant().fields.last() { |
7cac9316 XL |
223 | Some(f) => ty = f.ty(self, substs), |
224 | None => break, | |
225 | } | |
226 | } | |
227 | ||
94222f64 XL |
228 | ty::Tuple(tys) if let Some((&last_ty, _)) = tys.split_last() => { |
229 | ty = last_ty.expect_ty(); | |
7cac9316 XL |
230 | } |
231 | ||
94222f64 XL |
232 | ty::Tuple(_) => break, |
233 | ||
416331ca XL |
234 | ty::Projection(_) | ty::Opaque(..) => { |
235 | let normalized = normalize(ty); | |
236 | if ty == normalized { | |
237 | return ty; | |
238 | } else { | |
239 | ty = normalized; | |
240 | } | |
241 | } | |
242 | ||
7cac9316 XL |
243 | _ => { |
244 | break; | |
245 | } | |
e9174d1e SL |
246 | } |
247 | } | |
248 | ty | |
249 | } | |
250 | ||
60c5eb7d | 251 | /// Same as applying `struct_tail` on `source` and `target`, but only |
e9174d1e SL |
252 | /// keeps going as long as the two types are instances of the same |
253 | /// structure definitions. | |
a1dfa0c6 | 254 | /// For `(Foo<Foo<T>>, Foo<dyn Trait>)`, the result will be `(Foo<T>, Trait)`, |
e9174d1e | 255 | /// whereas struct_tail produces `T`, and `Trait`, respectively. |
416331ca XL |
256 | /// |
257 | /// Should only be called if the types have no inference variables and do | |
60c5eb7d | 258 | /// not need their lifetimes preserved (e.g., as part of codegen); otherwise, |
416331ca | 259 | /// normalization attempt may cause compiler bugs. |
dfeec247 XL |
260 | pub fn struct_lockstep_tails_erasing_lifetimes( |
261 | self, | |
262 | source: Ty<'tcx>, | |
263 | target: Ty<'tcx>, | |
264 | param_env: ty::ParamEnv<'tcx>, | |
265 | ) -> (Ty<'tcx>, Ty<'tcx>) { | |
416331ca | 266 | let tcx = self; |
dfeec247 XL |
267 | tcx.struct_lockstep_tails_with_normalize(source, target, |ty| { |
268 | tcx.normalize_erasing_regions(param_env, ty) | |
269 | }) | |
416331ca XL |
270 | } |
271 | ||
60c5eb7d | 272 | /// Same as applying `struct_tail` on `source` and `target`, but only |
416331ca XL |
273 | /// keeps going as long as the two types are instances of the same |
274 | /// structure definitions. | |
275 | /// For `(Foo<Foo<T>>, Foo<dyn Trait>)`, the result will be `(Foo<T>, Trait)`, | |
276 | /// whereas struct_tail produces `T`, and `Trait`, respectively. | |
277 | /// | |
278 | /// See also `struct_lockstep_tails_erasing_lifetimes`, which is suitable for use | |
279 | /// during codegen. | |
dfeec247 XL |
280 | pub fn struct_lockstep_tails_with_normalize( |
281 | self, | |
282 | source: Ty<'tcx>, | |
283 | target: Ty<'tcx>, | |
284 | normalize: impl Fn(Ty<'tcx>) -> Ty<'tcx>, | |
285 | ) -> (Ty<'tcx>, Ty<'tcx>) { | |
e9174d1e | 286 | let (mut a, mut b) = (source, target); |
041b39d2 | 287 | loop { |
1b1a35ee | 288 | match (&a.kind(), &b.kind()) { |
b7449926 | 289 | (&Adt(a_def, a_substs), &Adt(b_def, b_substs)) |
dfeec247 XL |
290 | if a_def == b_def && a_def.is_struct() => |
291 | { | |
2c00a5a8 | 292 | if let Some(f) = a_def.non_enum_variant().fields.last() { |
041b39d2 XL |
293 | a = f.ty(self, a_substs); |
294 | b = f.ty(self, b_substs); | |
295 | } else { | |
296 | break; | |
297 | } | |
dfeec247 XL |
298 | } |
299 | (&Tuple(a_tys), &Tuple(b_tys)) if a_tys.len() == b_tys.len() => { | |
041b39d2 | 300 | if let Some(a_last) = a_tys.last() { |
48663c56 XL |
301 | a = a_last.expect_ty(); |
302 | b = b_tys.last().unwrap().expect_ty(); | |
041b39d2 XL |
303 | } else { |
304 | break; | |
305 | } | |
dfeec247 | 306 | } |
ba9703b0 XL |
307 | (ty::Projection(_) | ty::Opaque(..), _) |
308 | | (_, ty::Projection(_) | ty::Opaque(..)) => { | |
416331ca XL |
309 | // If either side is a projection, attempt to |
310 | // progress via normalization. (Should be safe to | |
311 | // apply to both sides as normalization is | |
312 | // idempotent.) | |
313 | let a_norm = normalize(a); | |
314 | let b_norm = normalize(b); | |
315 | if a == a_norm && b == b_norm { | |
316 | break; | |
317 | } else { | |
318 | a = a_norm; | |
319 | b = b_norm; | |
320 | } | |
321 | } | |
322 | ||
cc61c64b | 323 | _ => break, |
e9174d1e SL |
324 | } |
325 | } | |
326 | (a, b) | |
327 | } | |
328 | ||
8bb4bdeb XL |
329 | /// Calculate the destructor of a given type. |
330 | pub fn calculate_dtor( | |
331 | self, | |
332 | adt_did: DefId, | |
29967ef6 | 333 | validate: impl Fn(Self, DefId) -> Result<(), ErrorReported>, |
8bb4bdeb | 334 | ) -> Option<ty::Destructor> { |
ba9703b0 | 335 | let drop_trait = self.lang_items().drop_trait()?; |
9fa01778 | 336 | self.ensure().coherent_trait(drop_trait); |
8bb4bdeb | 337 | |
7cac9316 | 338 | let ty = self.type_of(adt_did); |
29967ef6 | 339 | let dtor_did = self.find_map_relevant_impl(drop_trait, ty, |impl_did| { |
74b04a01 | 340 | if let Some(item) = self.associated_items(impl_did).in_definition_order().next() { |
0bf4aa26 | 341 | if validate(self, impl_did).is_ok() { |
29967ef6 | 342 | return Some(item.def_id); |
8bb4bdeb XL |
343 | } |
344 | } | |
29967ef6 | 345 | None |
8bb4bdeb XL |
346 | }); |
347 | ||
ff7c6d11 | 348 | Some(ty::Destructor { did: dtor_did? }) |
cc61c64b XL |
349 | } |
350 | ||
9fa01778 | 351 | /// Returns the set of types that are required to be alive in |
cc61c64b XL |
352 | /// order to run the destructor of `def` (see RFCs 769 and |
353 | /// 1238). | |
354 | /// | |
355 | /// Note that this returns only the constraints for the | |
356 | /// destructor of `def` itself. For the destructors of the | |
357 | /// contents, you need `adt_dtorck_constraint`. | |
dfeec247 | 358 | pub fn destructor_constraints(self, def: &'tcx ty::AdtDef) -> Vec<ty::subst::GenericArg<'tcx>> { |
cc61c64b XL |
359 | let dtor = match def.destructor(self) { |
360 | None => { | |
361 | debug!("destructor_constraints({:?}) - no dtor", def.did); | |
dfeec247 | 362 | return vec![]; |
cc61c64b | 363 | } |
dfeec247 | 364 | Some(dtor) => dtor.did, |
e9174d1e | 365 | }; |
b039eaaf | 366 | |
cc61c64b | 367 | let impl_def_id = self.associated_item(dtor).container.id(); |
7cac9316 | 368 | let impl_generics = self.generics_of(impl_def_id); |
cc61c64b XL |
369 | |
370 | // We have a destructor - all the parameters that are not | |
371 | // pure_wrt_drop (i.e, don't have a #[may_dangle] attribute) | |
372 | // must be live. | |
373 | ||
374 | // We need to return the list of parameters from the ADTs | |
375 | // generics/substs that correspond to impure parameters on the | |
376 | // impl's generics. This is a bit ugly, but conceptually simple: | |
377 | // | |
378 | // Suppose our ADT looks like the following | |
379 | // | |
380 | // struct S<X, Y, Z>(X, Y, Z); | |
381 | // | |
382 | // and the impl is | |
383 | // | |
384 | // impl<#[may_dangle] P0, P1, P2> Drop for S<P1, P2, P0> | |
385 | // | |
386 | // We want to return the parameters (X, Y). For that, we match | |
387 | // up the item-substs <X, Y, Z> with the substs on the impl ADT, | |
388 | // <P1, P2, P0>, and then look up which of the impl substs refer to | |
389 | // parameters marked as pure. | |
390 | ||
1b1a35ee | 391 | let impl_substs = match *self.type_of(impl_def_id).kind() { |
b7449926 | 392 | ty::Adt(def_, substs) if def_ == def => substs, |
dfeec247 | 393 | _ => bug!(), |
cc61c64b XL |
394 | }; |
395 | ||
1b1a35ee | 396 | let item_substs = match *self.type_of(def.did).kind() { |
b7449926 | 397 | ty::Adt(def_, substs) if def_ == def => substs, |
dfeec247 | 398 | _ => bug!(), |
cc61c64b XL |
399 | }; |
400 | ||
cdc7bbd5 | 401 | let result = iter::zip(item_substs, impl_substs) |
f9f354fc | 402 | .filter(|&(_, k)| { |
0531ce1d | 403 | match k.unpack() { |
e74abb32 | 404 | GenericArgKind::Lifetime(&ty::RegionKind::ReEarlyBound(ref ebr)) => { |
0531ce1d XL |
405 | !impl_generics.region_param(ebr, self).pure_wrt_drop |
406 | } | |
dfeec247 | 407 | GenericArgKind::Type(&ty::TyS { kind: ty::Param(ref pt), .. }) => { |
0531ce1d XL |
408 | !impl_generics.type_param(pt, self).pure_wrt_drop |
409 | } | |
e74abb32 | 410 | GenericArgKind::Const(&ty::Const { |
dfeec247 XL |
411 | val: ty::ConstKind::Param(ref pc), .. |
412 | }) => !impl_generics.const_param(pc, self).pure_wrt_drop, | |
413 | GenericArgKind::Lifetime(_) | |
414 | | GenericArgKind::Type(_) | |
415 | | GenericArgKind::Const(_) => { | |
532ac7d7 | 416 | // Not a type, const or region param: this should be reported |
0531ce1d XL |
417 | // as an error. |
418 | false | |
419 | } | |
cc61c64b | 420 | } |
0bf4aa26 | 421 | }) |
f9f354fc | 422 | .map(|(item_param, _)| item_param) |
0bf4aa26 | 423 | .collect(); |
cc61c64b XL |
424 | debug!("destructor_constraint({:?}) = {:?}", def.did, result); |
425 | result | |
b039eaaf | 426 | } |
9e0c209e | 427 | |
9fa01778 XL |
428 | /// Returns `true` if `def_id` refers to a closure (e.g., `|x| x * 2`). Note |
429 | /// that closures have a `DefId`, but the closure *expression* also | |
8faf50e0 XL |
430 | /// has a `HirId` that is located within the context where the |
431 | /// closure appears (and, sadly, a corresponding `NodeId`, since | |
432 | /// those are not yet phased out). The parent of the closure's | |
9fa01778 | 433 | /// `DefId` will also be the context where it appears. |
abe05a73 | 434 | pub fn is_closure(self, def_id: DefId) -> bool { |
f9f354fc | 435 | matches!(self.def_kind(def_id), DefKind::Closure | DefKind::Generator) |
abe05a73 XL |
436 | } |
437 | ||
9fa01778 | 438 | /// Returns `true` if `def_id` refers to a trait (i.e., `trait Foo { ... }`). |
8faf50e0 | 439 | pub fn is_trait(self, def_id: DefId) -> bool { |
f9f354fc | 440 | self.def_kind(def_id) == DefKind::Trait |
8faf50e0 XL |
441 | } |
442 | ||
9fa01778 XL |
443 | /// Returns `true` if `def_id` refers to a trait alias (i.e., `trait Foo = ...;`), |
444 | /// and `false` otherwise. | |
445 | pub fn is_trait_alias(self, def_id: DefId) -> bool { | |
f9f354fc | 446 | self.def_kind(def_id) == DefKind::TraitAlias |
9fa01778 XL |
447 | } |
448 | ||
449 | /// Returns `true` if this `DefId` refers to the implicit constructor for | |
450 | /// a tuple struct like `struct Foo(u32)`, and `false` otherwise. | |
532ac7d7 | 451 | pub fn is_constructor(self, def_id: DefId) -> bool { |
f9f354fc | 452 | matches!(self.def_kind(def_id), DefKind::Ctor(..)) |
8faf50e0 XL |
453 | } |
454 | ||
dc9dc135 | 455 | /// Given the def-ID of a fn or closure, returns the def-ID of |
ff7c6d11 | 456 | /// the innermost fn item that the closure is contained within. |
9fa01778 | 457 | /// This is a significant `DefId` because, when we do |
ff7c6d11 | 458 | /// type-checking, we type-check this fn item and all of its |
9fa01778 | 459 | /// (transitive) closures together. 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. | |
cc61c64b | 462 | pub fn closure_base_def_id(self, def_id: DefId) -> DefId { |
476ff2be | 463 | let mut def_id = def_id; |
abe05a73 | 464 | while self.is_closure(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. | |
531 | pub fn try_expand_impl_trait_type( | |
532 | self, | |
533 | def_id: DefId, | |
532ac7d7 | 534 | substs: SubstsRef<'tcx>, |
0731742a | 535 | ) -> Result<Ty<'tcx>, Ty<'tcx>> { |
0731742a XL |
536 | let mut visitor = OpaqueTypeExpander { |
537 | seen_opaque_tys: FxHashSet::default(), | |
e1599b0c | 538 | expanded_cache: FxHashMap::default(), |
3dfed10e | 539 | primary_def_id: Some(def_id), |
0731742a | 540 | found_recursion: false, |
94222f64 | 541 | found_any_recursion: false, |
3dfed10e | 542 | check_recursion: true, |
0731742a XL |
543 | tcx: self, |
544 | }; | |
3dfed10e | 545 | |
0731742a | 546 | let expanded_type = visitor.expand_opaque_ty(def_id, substs).unwrap(); |
dfeec247 | 547 | if visitor.found_recursion { Err(expanded_type) } else { Ok(expanded_type) } |
0731742a | 548 | } |
9e0c209e SL |
549 | } |
550 | ||
3dfed10e XL |
551 | struct OpaqueTypeExpander<'tcx> { |
552 | // Contains the DefIds of the opaque types that are currently being | |
553 | // expanded. When we expand an opaque type we insert the DefId of | |
554 | // that type, and when we finish expanding that type we remove the | |
555 | // its DefId. | |
556 | seen_opaque_tys: FxHashSet<DefId>, | |
557 | // Cache of all expansions we've seen so far. This is a critical | |
558 | // optimization for some large types produced by async fn trees. | |
559 | expanded_cache: FxHashMap<(DefId, SubstsRef<'tcx>), Ty<'tcx>>, | |
560 | primary_def_id: Option<DefId>, | |
561 | found_recursion: bool, | |
94222f64 | 562 | found_any_recursion: bool, |
3dfed10e XL |
563 | /// Whether or not to check for recursive opaque types. |
564 | /// This is `true` when we're explicitly checking for opaque type | |
565 | /// recursion, and 'false' otherwise to avoid unnecessary work. | |
566 | check_recursion: bool, | |
567 | tcx: TyCtxt<'tcx>, | |
568 | } | |
569 | ||
570 | impl<'tcx> OpaqueTypeExpander<'tcx> { | |
571 | fn expand_opaque_ty(&mut self, def_id: DefId, substs: SubstsRef<'tcx>) -> Option<Ty<'tcx>> { | |
94222f64 | 572 | if self.found_any_recursion { |
3dfed10e XL |
573 | return None; |
574 | } | |
575 | let substs = substs.fold_with(self); | |
576 | if !self.check_recursion || self.seen_opaque_tys.insert(def_id) { | |
577 | let expanded_ty = match self.expanded_cache.get(&(def_id, substs)) { | |
578 | Some(expanded_ty) => expanded_ty, | |
579 | None => { | |
580 | let generic_ty = self.tcx.type_of(def_id); | |
581 | let concrete_ty = generic_ty.subst(self.tcx, substs); | |
582 | let expanded_ty = self.fold_ty(concrete_ty); | |
583 | self.expanded_cache.insert((def_id, substs), expanded_ty); | |
584 | expanded_ty | |
585 | } | |
586 | }; | |
587 | if self.check_recursion { | |
588 | self.seen_opaque_tys.remove(&def_id); | |
589 | } | |
590 | Some(expanded_ty) | |
591 | } else { | |
592 | // If another opaque type that we contain is recursive, then it | |
593 | // will report the error, so we don't have to. | |
94222f64 | 594 | self.found_any_recursion = true; |
3dfed10e XL |
595 | self.found_recursion = def_id == *self.primary_def_id.as_ref().unwrap(); |
596 | None | |
597 | } | |
598 | } | |
599 | } | |
600 | ||
601 | impl<'tcx> TypeFolder<'tcx> for OpaqueTypeExpander<'tcx> { | |
602 | fn tcx(&self) -> TyCtxt<'tcx> { | |
603 | self.tcx | |
604 | } | |
605 | ||
606 | fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> { | |
607 | if let ty::Opaque(def_id, substs) = t.kind { | |
608 | self.expand_opaque_ty(def_id, substs).unwrap_or(t) | |
609 | } else if t.has_opaque_types() { | |
610 | t.super_fold_with(self) | |
611 | } else { | |
612 | t | |
613 | } | |
614 | } | |
615 | } | |
616 | ||
dc9dc135 | 617 | impl<'tcx> ty::TyS<'tcx> { |
dfeec247 XL |
618 | /// Returns the maximum value for the given numeric type (including `char`s) |
619 | /// or returns `None` if the type is not numeric. | |
620 | pub fn numeric_max_val(&'tcx self, tcx: TyCtxt<'tcx>) -> Option<&'tcx ty::Const<'tcx>> { | |
1b1a35ee | 621 | let val = match self.kind() { |
dfeec247 XL |
622 | ty::Int(_) | ty::Uint(_) => { |
623 | let (size, signed) = int_size_and_signed(tcx, self); | |
624 | let val = if signed { signed_max(size) as u128 } else { unsigned_max(size) }; | |
625 | Some(val) | |
626 | } | |
627 | ty::Char => Some(std::char::MAX as u128), | |
628 | ty::Float(fty) => Some(match fty { | |
5869c6ff XL |
629 | ty::FloatTy::F32 => rustc_apfloat::ieee::Single::INFINITY.to_bits(), |
630 | ty::FloatTy::F64 => rustc_apfloat::ieee::Double::INFINITY.to_bits(), | |
dfeec247 XL |
631 | }), |
632 | _ => None, | |
633 | }; | |
634 | val.map(|v| ty::Const::from_bits(tcx, v, ty::ParamEnv::empty().and(self))) | |
635 | } | |
636 | ||
637 | /// Returns the minimum value for the given numeric type (including `char`s) | |
638 | /// or returns `None` if the type is not numeric. | |
639 | pub fn numeric_min_val(&'tcx self, tcx: TyCtxt<'tcx>) -> Option<&'tcx ty::Const<'tcx>> { | |
1b1a35ee | 640 | let val = match self.kind() { |
dfeec247 XL |
641 | ty::Int(_) | ty::Uint(_) => { |
642 | let (size, signed) = int_size_and_signed(tcx, self); | |
29967ef6 | 643 | let val = if signed { size.truncate(signed_min(size) as u128) } else { 0 }; |
dfeec247 XL |
644 | Some(val) |
645 | } | |
646 | ty::Char => Some(0), | |
647 | ty::Float(fty) => Some(match fty { | |
5869c6ff XL |
648 | ty::FloatTy::F32 => (-::rustc_apfloat::ieee::Single::INFINITY).to_bits(), |
649 | ty::FloatTy::F64 => (-::rustc_apfloat::ieee::Double::INFINITY).to_bits(), | |
dfeec247 XL |
650 | }), |
651 | _ => None, | |
652 | }; | |
653 | val.map(|v| ty::Const::from_bits(tcx, v, ty::ParamEnv::empty().and(self))) | |
654 | } | |
655 | ||
0731742a XL |
656 | /// Checks whether values of this type `T` are *moved* or *copied* |
657 | /// when referenced -- this amounts to a check for whether `T: | |
658 | /// Copy`, but note that we **don't** consider lifetimes when | |
659 | /// doing this check. This means that we may generate MIR which | |
660 | /// does copies even when the type actually doesn't satisfy the | |
661 | /// full requirements for the `Copy` trait (cc #29149) -- this | |
662 | /// winds up being reported as an error during NLL borrow check. | |
dc9dc135 XL |
663 | pub fn is_copy_modulo_regions( |
664 | &'tcx self, | |
f035d41b | 665 | tcx_at: TyCtxtAt<'tcx>, |
dc9dc135 | 666 | param_env: ty::ParamEnv<'tcx>, |
dc9dc135 | 667 | ) -> bool { |
f035d41b | 668 | tcx_at.is_copy_raw(param_env.and(self)) |
e9174d1e SL |
669 | } |
670 | ||
0731742a XL |
671 | /// Checks whether values of this type `T` have a size known at |
672 | /// compile time (i.e., whether `T: Sized`). Lifetimes are ignored | |
673 | /// for the purposes of this check, so it can be an | |
674 | /// over-approximation in generic contexts, where one can have | |
675 | /// strange rules like `<T as Foo<'static>>::Bar: Sized` that | |
676 | /// actually carry lifetime requirements. | |
dc9dc135 | 677 | pub fn is_sized(&'tcx self, tcx_at: TyCtxtAt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> bool { |
74b04a01 | 678 | self.is_trivially_sized(tcx_at.tcx) || tcx_at.is_sized_raw(param_env.and(self)) |
e9174d1e SL |
679 | } |
680 | ||
0731742a | 681 | /// Checks whether values of this type `T` implement the `Freeze` |
94222f64 | 682 | /// trait -- frozen types are those that do not contain an |
9fa01778 | 683 | /// `UnsafeCell` anywhere. This is a language concept used to |
0731742a XL |
684 | /// distinguish "true immutability", which is relevant to |
685 | /// optimization as well as the rules around static values. Note | |
686 | /// that the `Freeze` trait is not exposed to end users and is | |
687 | /// effectively an implementation detail. | |
f035d41b XL |
688 | pub fn is_freeze(&'tcx self, tcx_at: TyCtxtAt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> bool { |
689 | self.is_trivially_freeze() || tcx_at.is_freeze_raw(param_env.and(self)) | |
74b04a01 XL |
690 | } |
691 | ||
692 | /// Fast path helper for testing if a type is `Freeze`. | |
693 | /// | |
694 | /// Returning true means the type is known to be `Freeze`. Returning | |
695 | /// `false` means nothing -- could be `Freeze`, might not be. | |
696 | fn is_trivially_freeze(&self) -> bool { | |
1b1a35ee | 697 | match self.kind() { |
74b04a01 XL |
698 | ty::Int(_) |
699 | | ty::Uint(_) | |
700 | | ty::Float(_) | |
701 | | ty::Bool | |
702 | | ty::Char | |
703 | | ty::Str | |
704 | | ty::Never | |
705 | | ty::Ref(..) | |
706 | | ty::RawPtr(_) | |
707 | | ty::FnDef(..) | |
f035d41b | 708 | | ty::Error(_) |
74b04a01 XL |
709 | | ty::FnPtr(_) => true, |
710 | ty::Tuple(_) => self.tuple_fields().all(Self::is_trivially_freeze), | |
711 | ty::Slice(elem_ty) | ty::Array(elem_ty, _) => elem_ty.is_trivially_freeze(), | |
712 | ty::Adt(..) | |
713 | | ty::Bound(..) | |
714 | | ty::Closure(..) | |
715 | | ty::Dynamic(..) | |
716 | | ty::Foreign(_) | |
717 | | ty::Generator(..) | |
718 | | ty::GeneratorWitness(_) | |
719 | | ty::Infer(_) | |
720 | | ty::Opaque(..) | |
721 | | ty::Param(_) | |
722 | | ty::Placeholder(_) | |
f9f354fc | 723 | | ty::Projection(_) => false, |
74b04a01 | 724 | } |
cc61c64b XL |
725 | } |
726 | ||
cdc7bbd5 XL |
727 | /// Checks whether values of this type `T` implement the `Unpin` trait. |
728 | pub fn is_unpin(&'tcx self, tcx_at: TyCtxtAt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> bool { | |
729 | self.is_trivially_unpin() || tcx_at.is_unpin_raw(param_env.and(self)) | |
730 | } | |
731 | ||
732 | /// Fast path helper for testing if a type is `Unpin`. | |
733 | /// | |
734 | /// Returning true means the type is known to be `Unpin`. Returning | |
735 | /// `false` means nothing -- could be `Unpin`, might not be. | |
736 | fn is_trivially_unpin(&self) -> bool { | |
737 | match self.kind() { | |
738 | ty::Int(_) | |
739 | | ty::Uint(_) | |
740 | | ty::Float(_) | |
741 | | ty::Bool | |
742 | | ty::Char | |
743 | | ty::Str | |
744 | | ty::Never | |
745 | | ty::Ref(..) | |
746 | | ty::RawPtr(_) | |
747 | | ty::FnDef(..) | |
748 | | ty::Error(_) | |
749 | | ty::FnPtr(_) => true, | |
750 | ty::Tuple(_) => self.tuple_fields().all(Self::is_trivially_unpin), | |
751 | ty::Slice(elem_ty) | ty::Array(elem_ty, _) => elem_ty.is_trivially_unpin(), | |
752 | ty::Adt(..) | |
753 | | ty::Bound(..) | |
754 | | ty::Closure(..) | |
755 | | ty::Dynamic(..) | |
756 | | ty::Foreign(_) | |
757 | | ty::Generator(..) | |
758 | | ty::GeneratorWitness(_) | |
759 | | ty::Infer(_) | |
760 | | ty::Opaque(..) | |
761 | | ty::Param(_) | |
762 | | ty::Placeholder(_) | |
763 | | ty::Projection(_) => false, | |
764 | } | |
765 | } | |
766 | ||
cc61c64b XL |
767 | /// If `ty.needs_drop(...)` returns `true`, then `ty` is definitely |
768 | /// non-copy and *might* have a destructor attached; if it returns | |
0731742a | 769 | /// `false`, then `ty` definitely has no destructor (i.e., no drop glue). |
cc61c64b XL |
770 | /// |
771 | /// (Note that this implies that if `ty` has a destructor attached, | |
772 | /// then `needs_drop` will definitely return `true` for `ty`.) | |
e74abb32 XL |
773 | /// |
774 | /// Note that this method is used to check eligible types in unions. | |
cc61c64b | 775 | #[inline] |
dc9dc135 | 776 | pub fn needs_drop(&'tcx self, tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> bool { |
74b04a01 XL |
777 | // Avoid querying in simple cases. |
778 | match needs_drop_components(self, &tcx.data_layout) { | |
779 | Err(AlwaysRequiresDrop) => true, | |
780 | Ok(components) => { | |
781 | let query_ty = match *components { | |
782 | [] => return false, | |
783 | // If we've got a single component, call the query with that | |
784 | // to increase the chance that we hit the query cache. | |
785 | [component_ty] => component_ty, | |
786 | _ => self, | |
787 | }; | |
788 | // This doesn't depend on regions, so try to minimize distinct | |
789 | // query keys used. | |
790 | let erased = tcx.normalize_erasing_regions(param_env, query_ty); | |
791 | tcx.needs_drop_raw(param_env.and(erased)) | |
792 | } | |
793 | } | |
cc61c64b XL |
794 | } |
795 | ||
17df50a5 XL |
796 | /// Checks if `ty` has has a significant drop. |
797 | /// | |
798 | /// Note that this method can return false even if `ty` has a destructor | |
799 | /// attached; even if that is the case then the adt has been marked with | |
800 | /// the attribute `rustc_insignificant_dtor`. | |
801 | /// | |
802 | /// Note that this method is used to check for change in drop order for | |
803 | /// 2229 drop reorder migration analysis. | |
804 | #[inline] | |
805 | pub fn has_significant_drop( | |
806 | &'tcx self, | |
807 | tcx: TyCtxt<'tcx>, | |
808 | param_env: ty::ParamEnv<'tcx>, | |
809 | ) -> bool { | |
810 | // Avoid querying in simple cases. | |
811 | match needs_drop_components(self, &tcx.data_layout) { | |
812 | Err(AlwaysRequiresDrop) => true, | |
813 | Ok(components) => { | |
814 | let query_ty = match *components { | |
815 | [] => return false, | |
816 | // If we've got a single component, call the query with that | |
817 | // to increase the chance that we hit the query cache. | |
818 | [component_ty] => component_ty, | |
819 | _ => self, | |
820 | }; | |
136023e0 XL |
821 | |
822 | // FIXME(#86868): We should be canonicalizing, or else moving this to a method of inference | |
823 | // context, or *something* like that, but for now just avoid passing inference | |
824 | // variables to queries that can't cope with them. Instead, conservatively | |
825 | // return "true" (may change drop order). | |
826 | if query_ty.needs_infer() { | |
827 | return true; | |
828 | } | |
829 | ||
17df50a5 XL |
830 | // This doesn't depend on regions, so try to minimize distinct |
831 | // query keys used. | |
832 | let erased = tcx.normalize_erasing_regions(param_env, query_ty); | |
833 | tcx.has_significant_drop_raw(param_env.and(erased)) | |
834 | } | |
835 | } | |
836 | } | |
837 | ||
f035d41b XL |
838 | /// Returns `true` if equality for this type is both reflexive and structural. |
839 | /// | |
840 | /// Reflexive equality for a type is indicated by an `Eq` impl for that type. | |
841 | /// | |
842 | /// Primitive types (`u32`, `str`) have structural equality by definition. For composite data | |
843 | /// types, equality for the type as a whole is structural when it is the same as equality | |
844 | /// between all components (fields, array elements, etc.) of that type. For ADTs, structural | |
845 | /// equality is indicated by an implementation of `PartialStructuralEq` and `StructuralEq` for | |
846 | /// that type. | |
847 | /// | |
848 | /// This function is "shallow" because it may return `true` for a composite type whose fields | |
849 | /// are not `StructuralEq`. For example, `[T; 4]` has structural equality regardless of `T` | |
850 | /// because equality for arrays is determined by the equality of each array element. If you | |
851 | /// want to know whether a given call to `PartialEq::eq` will proceed structurally all the way | |
852 | /// down, you will need to use a type visitor. | |
853 | #[inline] | |
854 | pub fn is_structural_eq_shallow(&'tcx self, tcx: TyCtxt<'tcx>) -> bool { | |
1b1a35ee | 855 | match self.kind() { |
f035d41b XL |
856 | // Look for an impl of both `PartialStructuralEq` and `StructuralEq`. |
857 | Adt(..) => tcx.has_structural_eq_impls(self), | |
858 | ||
859 | // Primitive types that satisfy `Eq`. | |
860 | Bool | Char | Int(_) | Uint(_) | Str | Never => true, | |
861 | ||
862 | // Composite types that satisfy `Eq` when all of their fields do. | |
863 | // | |
864 | // Because this function is "shallow", we return `true` for these composites regardless | |
865 | // of the type(s) contained within. | |
866 | Ref(..) | Array(..) | Slice(_) | Tuple(..) => true, | |
867 | ||
868 | // Raw pointers use bitwise comparison. | |
869 | RawPtr(_) | FnPtr(_) => true, | |
870 | ||
871 | // Floating point numbers are not `Eq`. | |
872 | Float(_) => false, | |
873 | ||
874 | // Conservatively return `false` for all others... | |
875 | ||
876 | // Anonymous function types | |
877 | FnDef(..) | Closure(..) | Dynamic(..) | Generator(..) => false, | |
878 | ||
879 | // Generic or inferred types | |
880 | // | |
881 | // FIXME(ecstaticmorse): Maybe we should `bug` here? This should probably only be | |
882 | // called for known, fully-monomorphized types. | |
883 | Projection(_) | Opaque(..) | Param(_) | Bound(..) | Placeholder(_) | Infer(_) => false, | |
884 | ||
885 | Foreign(_) | GeneratorWitness(..) | Error(_) => false, | |
886 | } | |
887 | } | |
888 | ||
0731742a | 889 | pub fn same_type(a: Ty<'tcx>, b: Ty<'tcx>) -> bool { |
1b1a35ee | 890 | match (&a.kind(), &b.kind()) { |
0731742a XL |
891 | (&Adt(did_a, substs_a), &Adt(did_b, substs_b)) => { |
892 | if did_a != did_b { | |
893 | return false; | |
894 | } | |
895 | ||
896 | substs_a.types().zip(substs_b.types()).all(|(a, b)| Self::same_type(a, b)) | |
897 | } | |
898 | _ => a == b, | |
899 | } | |
900 | } | |
901 | ||
e1599b0c XL |
902 | /// Peel off all reference types in this type until there are none left. |
903 | /// | |
904 | /// This method is idempotent, i.e. `ty.peel_refs().peel_refs() == ty.peel_refs()`. | |
905 | /// | |
906 | /// # Examples | |
907 | /// | |
908 | /// - `u8` -> `u8` | |
909 | /// - `&'a mut u8` -> `u8` | |
910 | /// - `&'a &'b u8` -> `u8` | |
911 | /// - `&'a *const &'b u8 -> *const &'b u8` | |
912 | pub fn peel_refs(&'tcx self) -> Ty<'tcx> { | |
913 | let mut ty = self; | |
1b1a35ee | 914 | while let Ref(_, inner_ty, _) = ty.kind() { |
e1599b0c XL |
915 | ty = inner_ty; |
916 | } | |
917 | ty | |
918 | } | |
136023e0 XL |
919 | |
920 | pub fn outer_exclusive_binder(&'tcx self) -> DebruijnIndex { | |
921 | self.outer_exclusive_binder | |
922 | } | |
e9174d1e | 923 | } |
7cac9316 | 924 | |
abe05a73 XL |
925 | pub enum ExplicitSelf<'tcx> { |
926 | ByValue, | |
927 | ByReference(ty::Region<'tcx>, hir::Mutability), | |
ff7c6d11 | 928 | ByRawPointer(hir::Mutability), |
abe05a73 | 929 | ByBox, |
dfeec247 | 930 | Other, |
abe05a73 XL |
931 | } |
932 | ||
933 | impl<'tcx> ExplicitSelf<'tcx> { | |
934 | /// Categorizes an explicit self declaration like `self: SomeType` | |
935 | /// into either `self`, `&self`, `&mut self`, `Box<self>`, or | |
936 | /// `Other`. | |
937 | /// This is mainly used to require the arbitrary_self_types feature | |
938 | /// in the case of `Other`, to improve error messages in the common cases, | |
939 | /// and to make `Other` non-object-safe. | |
940 | /// | |
941 | /// Examples: | |
942 | /// | |
943 | /// ``` | |
944 | /// impl<'a> Foo for &'a T { | |
945 | /// // Legal declarations: | |
946 | /// fn method1(self: &&'a T); // ExplicitSelf::ByReference | |
947 | /// fn method2(self: &'a T); // ExplicitSelf::ByValue | |
948 | /// fn method3(self: Box<&'a T>); // ExplicitSelf::ByBox | |
949 | /// fn method4(self: Rc<&'a T>); // ExplicitSelf::Other | |
950 | /// | |
951 | /// // Invalid cases will be caught by `check_method_receiver`: | |
952 | /// fn method_err1(self: &'a mut T); // ExplicitSelf::Other | |
953 | /// fn method_err2(self: &'static T) // ExplicitSelf::ByValue | |
954 | /// fn method_err3(self: &&T) // ExplicitSelf::ByReference | |
955 | /// } | |
956 | /// ``` | |
957 | /// | |
dfeec247 | 958 | pub fn determine<P>(self_arg_ty: Ty<'tcx>, is_self_ty: P) -> ExplicitSelf<'tcx> |
abe05a73 | 959 | where |
dfeec247 | 960 | P: Fn(Ty<'tcx>) -> bool, |
abe05a73 XL |
961 | { |
962 | use self::ExplicitSelf::*; | |
963 | ||
1b1a35ee | 964 | match *self_arg_ty.kind() { |
abe05a73 | 965 | _ if is_self_ty(self_arg_ty) => ByValue, |
dfeec247 XL |
966 | ty::Ref(region, ty, mutbl) if is_self_ty(ty) => ByReference(region, mutbl), |
967 | ty::RawPtr(ty::TypeAndMut { ty, mutbl }) if is_self_ty(ty) => ByRawPointer(mutbl), | |
968 | ty::Adt(def, _) if def.is_box() && is_self_ty(self_arg_ty.boxed_ty()) => ByBox, | |
969 | _ => Other, | |
abe05a73 XL |
970 | } |
971 | } | |
972 | } | |
74b04a01 XL |
973 | |
974 | /// Returns a list of types such that the given type needs drop if and only if | |
975 | /// *any* of the returned types need drop. Returns `Err(AlwaysRequiresDrop)` if | |
976 | /// this type always needs drop. | |
977 | pub fn needs_drop_components( | |
978 | ty: Ty<'tcx>, | |
979 | target_layout: &TargetDataLayout, | |
980 | ) -> Result<SmallVec<[Ty<'tcx>; 2]>, AlwaysRequiresDrop> { | |
1b1a35ee | 981 | match ty.kind() { |
74b04a01 XL |
982 | ty::Infer(ty::FreshIntTy(_)) |
983 | | ty::Infer(ty::FreshFloatTy(_)) | |
984 | | ty::Bool | |
985 | | ty::Int(_) | |
986 | | ty::Uint(_) | |
987 | | ty::Float(_) | |
988 | | ty::Never | |
989 | | ty::FnDef(..) | |
990 | | ty::FnPtr(_) | |
991 | | ty::Char | |
992 | | ty::GeneratorWitness(..) | |
993 | | ty::RawPtr(_) | |
994 | | ty::Ref(..) | |
995 | | ty::Str => Ok(SmallVec::new()), | |
996 | ||
997 | // Foreign types can never have destructors. | |
998 | ty::Foreign(..) => Ok(SmallVec::new()), | |
999 | ||
f035d41b | 1000 | ty::Dynamic(..) | ty::Error(_) => Err(AlwaysRequiresDrop), |
74b04a01 XL |
1001 | |
1002 | ty::Slice(ty) => needs_drop_components(ty, target_layout), | |
1003 | ty::Array(elem_ty, size) => { | |
1004 | match needs_drop_components(elem_ty, target_layout) { | |
1005 | Ok(v) if v.is_empty() => Ok(v), | |
1006 | res => match size.val.try_to_bits(target_layout.pointer_size) { | |
1007 | // Arrays of size zero don't need drop, even if their element | |
1008 | // type does. | |
1009 | Some(0) => Ok(SmallVec::new()), | |
1010 | Some(_) => res, | |
1011 | // We don't know which of the cases above we are in, so | |
1012 | // return the whole type and let the caller decide what to | |
1013 | // do. | |
1014 | None => Ok(smallvec![ty]), | |
1015 | }, | |
1016 | } | |
1017 | } | |
1018 | // If any field needs drop, then the whole tuple does. | |
1019 | ty::Tuple(..) => ty.tuple_fields().try_fold(SmallVec::new(), move |mut acc, elem| { | |
1020 | acc.extend(needs_drop_components(elem, target_layout)?); | |
1021 | Ok(acc) | |
1022 | }), | |
1023 | ||
1024 | // These require checking for `Copy` bounds or `Adt` destructors. | |
1025 | ty::Adt(..) | |
1026 | | ty::Projection(..) | |
74b04a01 XL |
1027 | | ty::Param(_) |
1028 | | ty::Bound(..) | |
1029 | | ty::Placeholder(..) | |
1030 | | ty::Opaque(..) | |
1031 | | ty::Infer(_) | |
ba9703b0 XL |
1032 | | ty::Closure(..) |
1033 | | ty::Generator(..) => Ok(smallvec![ty]), | |
74b04a01 XL |
1034 | } |
1035 | } | |
1036 | ||
fc512014 XL |
1037 | // Does the equivalent of |
1038 | // ``` | |
1039 | // let v = self.iter().map(|p| p.fold_with(folder)).collect::<SmallVec<[_; 8]>>(); | |
1040 | // folder.tcx().intern_*(&v) | |
1041 | // ``` | |
1042 | pub fn fold_list<'tcx, F, T>( | |
1043 | list: &'tcx ty::List<T>, | |
1044 | folder: &mut F, | |
1045 | intern: impl FnOnce(TyCtxt<'tcx>, &[T]) -> &'tcx ty::List<T>, | |
1046 | ) -> &'tcx ty::List<T> | |
1047 | where | |
1048 | F: TypeFolder<'tcx>, | |
1049 | T: TypeFoldable<'tcx> + PartialEq + Copy, | |
1050 | { | |
1051 | let mut iter = list.iter(); | |
1052 | // Look for the first element that changed | |
1053 | if let Some((i, new_t)) = iter.by_ref().enumerate().find_map(|(i, t)| { | |
1054 | let new_t = t.fold_with(folder); | |
1055 | if new_t == t { None } else { Some((i, new_t)) } | |
1056 | }) { | |
1057 | // An element changed, prepare to intern the resulting list | |
1058 | let mut new_list = SmallVec::<[_; 8]>::with_capacity(list.len()); | |
1059 | new_list.extend_from_slice(&list[..i]); | |
1060 | new_list.push(new_t); | |
1061 | new_list.extend(iter.map(|t| t.fold_with(folder))); | |
1062 | intern(folder.tcx(), &new_list) | |
1063 | } else { | |
1064 | list | |
1065 | } | |
1066 | } | |
1067 | ||
3dfed10e | 1068 | #[derive(Copy, Clone, Debug, HashStable, TyEncodable, TyDecodable)] |
74b04a01 | 1069 | pub struct AlwaysRequiresDrop; |
3dfed10e XL |
1070 | |
1071 | /// Normalizes all opaque types in the given value, replacing them | |
1072 | /// with their underlying types. | |
1073 | pub fn normalize_opaque_types( | |
1074 | tcx: TyCtxt<'tcx>, | |
1075 | val: &'tcx List<ty::Predicate<'tcx>>, | |
1076 | ) -> &'tcx List<ty::Predicate<'tcx>> { | |
1077 | let mut visitor = OpaqueTypeExpander { | |
1078 | seen_opaque_tys: FxHashSet::default(), | |
1079 | expanded_cache: FxHashMap::default(), | |
1080 | primary_def_id: None, | |
1081 | found_recursion: false, | |
94222f64 | 1082 | found_any_recursion: false, |
3dfed10e XL |
1083 | check_recursion: false, |
1084 | tcx, | |
1085 | }; | |
1086 | val.fold_with(&mut visitor) | |
1087 | } | |
1088 | ||
1089 | pub fn provide(providers: &mut ty::query::Providers) { | |
1090 | *providers = ty::query::Providers { normalize_opaque_types, ..*providers } | |
1091 | } |