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Commit | Line | Data |
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0731742a XL |
1 | //! Conversion from AST representation of types to the `ty.rs` representation. |
2 | //! The main routine here is `ast_ty_to_ty()`; each use is parameterized by an | |
3 | //! instance of `AstConv`. | |
1a4d82fc | 4 | |
3dfed10e XL |
5 | mod errors; |
6 | mod generics; | |
dfeec247 | 7 | |
3dfed10e | 8 | use crate::bounds::Bounds; |
5099ac24 | 9 | use crate::collect::HirPlaceholderCollector; |
1b1a35ee XL |
10 | use crate::errors::{ |
11 | AmbiguousLifetimeBound, MultipleRelaxedDefaultBounds, TraitObjectDeclaredWithNoTraits, | |
12 | TypeofReservedKeywordUsed, ValueOfAssociatedStructAlreadySpecified, | |
13 | }; | |
9fa01778 | 14 | use crate::middle::resolve_lifetime as rl; |
dfeec247 | 15 | use crate::require_c_abi_if_c_variadic; |
a2a8927a | 16 | use rustc_ast::TraitObjectSyntax; |
dfeec247 | 17 | use rustc_data_structures::fx::{FxHashMap, FxHashSet}; |
5e7ed085 | 18 | use rustc_errors::{ |
923072b8 | 19 | struct_span_err, Applicability, DiagnosticBuilder, ErrorGuaranteed, FatalError, MultiSpan, |
5e7ed085 | 20 | }; |
dfeec247 | 21 | use rustc_hir as hir; |
74b04a01 | 22 | use rustc_hir::def::{CtorOf, DefKind, Namespace, Res}; |
f9f354fc | 23 | use rustc_hir::def_id::{DefId, LocalDefId}; |
ba9703b0 | 24 | use rustc_hir::intravisit::{walk_generics, Visitor as _}; |
3dfed10e | 25 | use rustc_hir::lang_items::LangItem; |
923072b8 FG |
26 | use rustc_hir::{GenericArg, GenericArgs, OpaqueTyOrigin}; |
27 | use rustc_middle::middle::stability::AllowUnstable; | |
94222f64 | 28 | use rustc_middle::ty::subst::{self, GenericArgKind, InternalSubsts, Subst, SubstsRef}; |
3dfed10e | 29 | use rustc_middle::ty::GenericParamDefKind; |
923072b8 FG |
30 | use rustc_middle::ty::{ |
31 | self, Const, DefIdTree, EarlyBinder, IsSuggestable, Ty, TyCtxt, TypeFoldable, | |
32 | }; | |
a2a8927a XL |
33 | use rustc_session::lint::builtin::{AMBIGUOUS_ASSOCIATED_ITEMS, BARE_TRAIT_OBJECTS}; |
34 | use rustc_span::edition::Edition; | |
fc512014 | 35 | use rustc_span::lev_distance::find_best_match_for_name; |
923072b8 | 36 | use rustc_span::symbol::{kw, Ident, Symbol}; |
3dfed10e | 37 | use rustc_span::{Span, DUMMY_SP}; |
83c7162d | 38 | use rustc_target::spec::abi; |
ba9703b0 XL |
39 | use rustc_trait_selection::traits; |
40 | use rustc_trait_selection::traits::astconv_object_safety_violations; | |
41 | use rustc_trait_selection::traits::error_reporting::report_object_safety_error; | |
42 | use rustc_trait_selection::traits::wf::object_region_bounds; | |
0731742a | 43 | |
ba9703b0 | 44 | use smallvec::SmallVec; |
0731742a | 45 | use std::collections::BTreeSet; |
0731742a XL |
46 | use std::slice; |
47 | ||
0731742a XL |
48 | #[derive(Debug)] |
49 | pub struct PathSeg(pub DefId, pub usize); | |
e9174d1e | 50 | |
dc9dc135 XL |
51 | pub trait AstConv<'tcx> { |
52 | fn tcx<'a>(&'a self) -> TyCtxt<'tcx>; | |
1a4d82fc | 53 | |
60c5eb7d XL |
54 | fn item_def_id(&self) -> Option<DefId>; |
55 | ||
6a06907d XL |
56 | /// Returns predicates in scope of the form `X: Foo<T>`, where `X` |
57 | /// is a type parameter `X` with the given id `def_id` and T | |
58 | /// matches `assoc_name`. This is a subset of the full set of | |
59 | /// predicates. | |
416331ca XL |
60 | /// |
61 | /// This is used for one specific purpose: resolving "short-hand" | |
62 | /// associated type references like `T::Item`. In principle, we | |
63 | /// would do that by first getting the full set of predicates in | |
64 | /// scope and then filtering down to find those that apply to `T`, | |
65 | /// but this can lead to cycle errors. The problem is that we have | |
66 | /// to do this resolution *in order to create the predicates in | |
67 | /// the first place*. Hence, we have this "special pass". | |
6a06907d XL |
68 | fn get_type_parameter_bounds( |
69 | &self, | |
70 | span: Span, | |
71 | def_id: DefId, | |
72 | assoc_name: Ident, | |
73 | ) -> ty::GenericPredicates<'tcx>; | |
c34b1796 | 74 | |
dc9dc135 | 75 | /// Returns the lifetime to use when a lifetime is omitted (and not elided). |
dfeec247 XL |
76 | fn re_infer(&self, param: Option<&ty::GenericParamDef>, span: Span) |
77 | -> Option<ty::Region<'tcx>>; | |
32a655c1 | 78 | |
dc9dc135 XL |
79 | /// Returns the type to use when a type is omitted. |
80 | fn ty_infer(&self, param: Option<&ty::GenericParamDef>, span: Span) -> Ty<'tcx>; | |
9e0c209e | 81 | |
dfeec247 XL |
82 | /// Returns `true` if `_` is allowed in type signatures in the current context. |
83 | fn allow_ty_infer(&self) -> bool; | |
84 | ||
dc9dc135 XL |
85 | /// Returns the const to use when a const is omitted. |
86 | fn ct_infer( | |
87 | &self, | |
88 | ty: Ty<'tcx>, | |
89 | param: Option<&ty::GenericParamDef>, | |
90 | span: Span, | |
5099ac24 | 91 | ) -> Const<'tcx>; |
1a4d82fc JJ |
92 | |
93 | /// Projecting an associated type from a (potentially) | |
94 | /// higher-ranked trait reference is more complicated, because of | |
95 | /// the possibility of late-bound regions appearing in the | |
96 | /// associated type binding. This is not legal in function | |
97 | /// signatures for that reason. In a function body, we can always | |
98 | /// handle it because we can use inference variables to remove the | |
99 | /// late-bound regions. | |
dfeec247 XL |
100 | fn projected_ty_from_poly_trait_ref( |
101 | &self, | |
102 | span: Span, | |
103 | item_def_id: DefId, | |
104 | item_segment: &hir::PathSegment<'_>, | |
105 | poly_trait_ref: ty::PolyTraitRef<'tcx>, | |
106 | ) -> Ty<'tcx>; | |
1a4d82fc | 107 | |
8bb4bdeb XL |
108 | /// Normalize an associated type coming from the user. |
109 | fn normalize_ty(&self, span: Span, ty: Ty<'tcx>) -> Ty<'tcx>; | |
a7813a04 XL |
110 | |
111 | /// Invoked when we encounter an error from some prior pass | |
0731742a | 112 | /// (e.g., resolve) that is translated into a ty-error. This is |
a7813a04 XL |
113 | /// used to help suppress derived errors typeck might otherwise |
114 | /// report. | |
115 | fn set_tainted_by_errors(&self); | |
ea8adc8c XL |
116 | |
117 | fn record_ty(&self, hir_id: hir::HirId, ty: Ty<'tcx>, span: Span); | |
a7813a04 XL |
118 | } |
119 | ||
5869c6ff | 120 | #[derive(Debug)] |
dc9dc135 | 121 | struct ConvertedBinding<'a, 'tcx> { |
17df50a5 | 122 | hir_id: hir::HirId, |
f9f354fc | 123 | item_name: Ident, |
dc9dc135 | 124 | kind: ConvertedBindingKind<'a, 'tcx>, |
5869c6ff | 125 | gen_args: &'a GenericArgs<'a>, |
a7813a04 | 126 | span: Span, |
1a4d82fc JJ |
127 | } |
128 | ||
5869c6ff | 129 | #[derive(Debug)] |
dc9dc135 | 130 | enum ConvertedBindingKind<'a, 'tcx> { |
5099ac24 | 131 | Equality(ty::Term<'tcx>), |
dfeec247 | 132 | Constraint(&'a [hir::GenericBound<'a>]), |
dc9dc135 XL |
133 | } |
134 | ||
f9f354fc XL |
135 | /// New-typed boolean indicating whether explicit late-bound lifetimes |
136 | /// are present in a set of generic arguments. | |
137 | /// | |
138 | /// For example if we have some method `fn f<'a>(&'a self)` implemented | |
139 | /// for some type `T`, although `f` is generic in the lifetime `'a`, `'a` | |
140 | /// is late-bound so should not be provided explicitly. Thus, if `f` is | |
141 | /// instantiated with some generic arguments providing `'a` explicitly, | |
142 | /// we taint those arguments with `ExplicitLateBound::Yes` so that we | |
143 | /// can provide an appropriate diagnostic later. | |
144 | #[derive(Copy, Clone, PartialEq)] | |
145 | pub enum ExplicitLateBound { | |
146 | Yes, | |
147 | No, | |
148 | } | |
149 | ||
5869c6ff XL |
150 | #[derive(Copy, Clone, PartialEq)] |
151 | pub enum IsMethodCall { | |
152 | Yes, | |
153 | No, | |
154 | } | |
155 | ||
3dfed10e XL |
156 | /// Denotes the "position" of a generic argument, indicating if it is a generic type, |
157 | /// generic function or generic method call. | |
f9f354fc | 158 | #[derive(Copy, Clone, PartialEq)] |
3dfed10e | 159 | pub(crate) enum GenericArgPosition { |
b7449926 | 160 | Type, |
0731742a | 161 | Value, // e.g., functions |
b7449926 | 162 | MethodCall, |
94b46f34 XL |
163 | } |
164 | ||
74b04a01 XL |
165 | /// A marker denoting that the generic arguments that were |
166 | /// provided did not match the respective generic parameters. | |
f9f354fc | 167 | #[derive(Clone, Default)] |
74b04a01 XL |
168 | pub struct GenericArgCountMismatch { |
169 | /// Indicates whether a fatal error was reported (`Some`), or just a lint (`None`). | |
5e7ed085 | 170 | pub reported: Option<ErrorGuaranteed>, |
74b04a01 XL |
171 | /// A list of spans of arguments provided that were not valid. |
172 | pub invalid_args: Vec<Span>, | |
173 | } | |
174 | ||
f9f354fc XL |
175 | /// Decorates the result of a generic argument count mismatch |
176 | /// check with whether explicit late bounds were provided. | |
177 | #[derive(Clone)] | |
178 | pub struct GenericArgCountResult { | |
179 | pub explicit_late_bound: ExplicitLateBound, | |
180 | pub correct: Result<(), GenericArgCountMismatch>, | |
181 | } | |
182 | ||
fc512014 XL |
183 | pub trait CreateSubstsForGenericArgsCtxt<'a, 'tcx> { |
184 | fn args_for_def_id(&mut self, def_id: DefId) -> (Option<&'a GenericArgs<'a>>, bool); | |
185 | ||
186 | fn provided_kind( | |
187 | &mut self, | |
188 | param: &ty::GenericParamDef, | |
189 | arg: &GenericArg<'_>, | |
190 | ) -> subst::GenericArg<'tcx>; | |
191 | ||
192 | fn inferred_kind( | |
193 | &mut self, | |
194 | substs: Option<&[subst::GenericArg<'tcx>]>, | |
195 | param: &ty::GenericParamDef, | |
196 | infer_args: bool, | |
197 | ) -> subst::GenericArg<'tcx>; | |
198 | } | |
199 | ||
dc9dc135 | 200 | impl<'o, 'tcx> dyn AstConv<'tcx> + 'o { |
cdc7bbd5 | 201 | #[tracing::instrument(level = "debug", skip(self))] |
dfeec247 XL |
202 | pub fn ast_region_to_region( |
203 | &self, | |
32a655c1 | 204 | lifetime: &hir::Lifetime, |
dfeec247 XL |
205 | def: Option<&ty::GenericParamDef>, |
206 | ) -> ty::Region<'tcx> { | |
32a655c1 | 207 | let tcx = self.tcx(); |
3dfed10e | 208 | let lifetime_name = |def_id| tcx.hir().name(tcx.hir().local_def_id_to_hir_id(def_id)); |
ea8adc8c | 209 | |
9fa01778 | 210 | let r = match tcx.named_region(lifetime.hir_id) { |
dfeec247 | 211 | Some(rl::Region::Static) => tcx.lifetimes.re_static, |
32a655c1 | 212 | |
5e7ed085 | 213 | Some(rl::Region::LateBound(debruijn, index, def_id)) => { |
cdc7bbd5 XL |
214 | let name = lifetime_name(def_id.expect_local()); |
215 | let br = ty::BoundRegion { | |
216 | var: ty::BoundVar::from_u32(index), | |
217 | kind: ty::BrNamed(def_id, name), | |
218 | }; | |
fc512014 | 219 | tcx.mk_region(ty::ReLateBound(debruijn, br)) |
32a655c1 SL |
220 | } |
221 | ||
cdc7bbd5 XL |
222 | Some(rl::Region::LateBoundAnon(debruijn, index, anon_index)) => { |
223 | let br = ty::BoundRegion { | |
224 | var: ty::BoundVar::from_u32(index), | |
225 | kind: ty::BrAnon(anon_index), | |
226 | }; | |
fc512014 | 227 | tcx.mk_region(ty::ReLateBound(debruijn, br)) |
32a655c1 SL |
228 | } |
229 | ||
5e7ed085 | 230 | Some(rl::Region::EarlyBound(index, id)) => { |
f9f354fc | 231 | let name = lifetime_name(id.expect_local()); |
dfeec247 | 232 | tcx.mk_region(ty::ReEarlyBound(ty::EarlyBoundRegion { def_id: id, index, name })) |
32a655c1 SL |
233 | } |
234 | ||
ea8adc8c | 235 | Some(rl::Region::Free(scope, id)) => { |
f9f354fc | 236 | let name = lifetime_name(id.expect_local()); |
32a655c1 | 237 | tcx.mk_region(ty::ReFree(ty::FreeRegion { |
7cac9316 | 238 | scope, |
dfeec247 | 239 | bound_region: ty::BrNamed(id, name), |
32a655c1 | 240 | })) |
5bcae85e | 241 | |
0bf4aa26 | 242 | // (*) -- not late-bound, won't change |
32a655c1 | 243 | } |
5bcae85e | 244 | |
32a655c1 | 245 | None => { |
dfeec247 | 246 | self.re_infer(def, lifetime.span).unwrap_or_else(|| { |
cdc7bbd5 XL |
247 | debug!(?lifetime, "unelided lifetime in signature"); |
248 | ||
dfeec247 XL |
249 | // This indicates an illegal lifetime |
250 | // elision. `resolve_lifetime` should have | |
251 | // reported an error in this case -- but if | |
252 | // not, let's error out. | |
253 | tcx.sess.delay_span_bug(lifetime.span, "unelided lifetime in signature"); | |
254 | ||
255 | // Supply some dummy value. We don't have an | |
256 | // `re_error`, annoyingly, so use `'static`. | |
257 | tcx.lifetimes.re_static | |
258 | }) | |
32a655c1 | 259 | } |
a7813a04 | 260 | }; |
1a4d82fc | 261 | |
dfeec247 | 262 | debug!("ast_region_to_region(lifetime={:?}) yields {:?}", lifetime, r); |
1a4d82fc | 263 | |
a7813a04 XL |
264 | r |
265 | } | |
1a4d82fc | 266 | |
a7813a04 XL |
267 | /// Given a path `path` that refers to an item `I` with the declared generics `decl_generics`, |
268 | /// returns an appropriate set of substitutions for this particular reference to `I`. | |
dfeec247 XL |
269 | pub fn ast_path_substs_for_ty( |
270 | &self, | |
a7813a04 | 271 | span: Span, |
9e0c209e | 272 | def_id: DefId, |
dfeec247 XL |
273 | item_segment: &hir::PathSegment<'_>, |
274 | ) -> SubstsRef<'tcx> { | |
cdc7bbd5 | 275 | let (substs, _) = self.create_substs_for_ast_path( |
dc9dc135 XL |
276 | span, |
277 | def_id, | |
dfeec247 | 278 | &[], |
5869c6ff XL |
279 | item_segment, |
280 | item_segment.args(), | |
dc9dc135 XL |
281 | item_segment.infer_args, |
282 | None, | |
283 | ); | |
cdc7bbd5 | 284 | let assoc_bindings = self.create_assoc_bindings_for_generic_args(item_segment.args()); |
1a4d82fc | 285 | |
f9f354fc XL |
286 | if let Some(b) = assoc_bindings.first() { |
287 | Self::prohibit_assoc_ty_binding(self.tcx(), b.span); | |
288 | } | |
1a4d82fc | 289 | |
9e0c209e | 290 | substs |
a7813a04 | 291 | } |
c34b1796 | 292 | |
48663c56 | 293 | /// Given the type/lifetime/const arguments provided to some path (along with |
dc9dc135 | 294 | /// an implicit `Self`, if this is a trait reference), returns the complete |
9e0c209e | 295 | /// set of substitutions. This may involve applying defaulted type parameters. |
5e7ed085 | 296 | /// Constraints on associated types are created from `create_assoc_bindings_for_generic_args`. |
dc9dc135 XL |
297 | /// |
298 | /// Example: | |
299 | /// | |
04454e1e FG |
300 | /// ```ignore (illustrative) |
301 | /// T: std::ops::Index<usize, Output = u32> | |
302 | /// // ^1 ^^^^^^^^^^^^^^2 ^^^^3 ^^^^^^^^^^^4 | |
dc9dc135 XL |
303 | /// ``` |
304 | /// | |
305 | /// 1. The `self_ty` here would refer to the type `T`. | |
306 | /// 2. The path in question is the path to the trait `std::ops::Index`, | |
307 | /// which will have been resolved to a `def_id` | |
308 | /// 3. The `generic_args` contains info on the `<...>` contents. The `usize` type | |
309 | /// parameters are returned in the `SubstsRef`, the associated type bindings like | |
5099ac24 | 310 | /// `Output = u32` are returned from `create_assoc_bindings_for_generic_args`. |
9e0c209e SL |
311 | /// |
312 | /// Note that the type listing given here is *exactly* what the user provided. | |
dfeec247 XL |
313 | /// |
314 | /// For (generic) associated types | |
315 | /// | |
04454e1e | 316 | /// ```ignore (illustrative) |
dfeec247 XL |
317 | /// <Vec<u8> as Iterable<u8>>::Iter::<'a> |
318 | /// ``` | |
319 | /// | |
320 | /// We have the parent substs are the substs for the parent trait: | |
321 | /// `[Vec<u8>, u8]` and `generic_args` are the arguments for the associated | |
322 | /// type itself: `['a]`. The returned `SubstsRef` concatenates these two | |
323 | /// lists: `[Vec<u8>, u8, 'a]`. | |
cdc7bbd5 | 324 | #[tracing::instrument(level = "debug", skip(self, span))] |
dfeec247 XL |
325 | fn create_substs_for_ast_path<'a>( |
326 | &self, | |
a7813a04 | 327 | span: Span, |
9e0c209e | 328 | def_id: DefId, |
dfeec247 | 329 | parent_substs: &[subst::GenericArg<'tcx>], |
5869c6ff | 330 | seg: &hir::PathSegment<'_>, |
dfeec247 | 331 | generic_args: &'a hir::GenericArgs<'_>, |
dc9dc135 | 332 | infer_args: bool, |
dfeec247 | 333 | self_ty: Option<Ty<'tcx>>, |
cdc7bbd5 | 334 | ) -> (SubstsRef<'tcx>, GenericArgCountResult) { |
a7813a04 XL |
335 | // If the type is parameterized by this region, then replace this |
336 | // region with the current anon region binding (in other words, | |
337 | // whatever & would get replaced with). | |
94b46f34 | 338 | |
b7449926 | 339 | let tcx = self.tcx(); |
5869c6ff XL |
340 | let generics = tcx.generics_of(def_id); |
341 | debug!("generics: {:?}", generics); | |
85aaf69f | 342 | |
5869c6ff XL |
343 | if generics.has_self { |
344 | if generics.parent.is_some() { | |
dfeec247 XL |
345 | // The parent is a trait so it should have at least one subst |
346 | // for the `Self` type. | |
347 | assert!(!parent_substs.is_empty()) | |
348 | } else { | |
349 | // This item (presumably a trait) needs a self-type. | |
350 | assert!(self_ty.is_some()); | |
351 | } | |
352 | } else { | |
353 | assert!(self_ty.is_none() && parent_substs.is_empty()); | |
354 | } | |
a7813a04 | 355 | |
f9f354fc | 356 | let arg_count = Self::check_generic_arg_count( |
0731742a | 357 | tcx, |
b7449926 | 358 | span, |
5869c6ff XL |
359 | def_id, |
360 | seg, | |
c295e0f8 XL |
361 | generics, |
362 | generic_args, | |
b7449926 | 363 | GenericArgPosition::Type, |
dfeec247 | 364 | self_ty.is_some(), |
dc9dc135 | 365 | infer_args, |
b7449926 | 366 | ); |
1a4d82fc | 367 | |
fc512014 XL |
368 | // Skip processing if type has no generic parameters. |
369 | // Traits always have `Self` as a generic parameter, which means they will not return early | |
370 | // here and so associated type bindings will be handled regardless of whether there are any | |
371 | // non-`Self` generic parameters. | |
c295e0f8 | 372 | if generics.params.is_empty() { |
cdc7bbd5 | 373 | return (tcx.intern_substs(&[]), arg_count); |
fc512014 XL |
374 | } |
375 | ||
dfeec247 | 376 | let is_object = self_ty.map_or(false, |ty| ty == self.tcx().types.trait_object_dummy_self); |
fc512014 XL |
377 | |
378 | struct SubstsForAstPathCtxt<'a, 'tcx> { | |
379 | astconv: &'a (dyn AstConv<'tcx> + 'a), | |
380 | def_id: DefId, | |
381 | generic_args: &'a GenericArgs<'a>, | |
382 | span: Span, | |
383 | missing_type_params: Vec<String>, | |
384 | inferred_params: Vec<Span>, | |
385 | infer_args: bool, | |
386 | is_object: bool, | |
387 | } | |
388 | ||
389 | impl<'tcx, 'a> SubstsForAstPathCtxt<'tcx, 'a> { | |
390 | fn default_needs_object_self(&mut self, param: &ty::GenericParamDef) -> bool { | |
391 | let tcx = self.astconv.tcx(); | |
392 | if let GenericParamDefKind::Type { has_default, .. } = param.kind { | |
393 | if self.is_object && has_default { | |
394 | let default_ty = tcx.at(self.span).type_of(param.def_id); | |
395 | let self_param = tcx.types.self_param; | |
5099ac24 | 396 | if default_ty.walk().any(|arg| arg == self_param.into()) { |
fc512014 XL |
397 | // There is no suitable inference default for a type parameter |
398 | // that references self, in an object type. | |
399 | return true; | |
400 | } | |
94b46f34 | 401 | } |
9e0c209e | 402 | } |
9e0c209e | 403 | |
fc512014 XL |
404 | false |
405 | } | |
406 | } | |
9e0c209e | 407 | |
fc512014 XL |
408 | impl<'a, 'tcx> CreateSubstsForGenericArgsCtxt<'a, 'tcx> for SubstsForAstPathCtxt<'a, 'tcx> { |
409 | fn args_for_def_id(&mut self, did: DefId) -> (Option<&'a GenericArgs<'a>>, bool) { | |
410 | if did == self.def_id { | |
411 | (Some(self.generic_args), self.infer_args) | |
74b04a01 XL |
412 | } else { |
413 | // The last component of this tuple is unimportant. | |
414 | (None, false) | |
415 | } | |
fc512014 XL |
416 | } |
417 | ||
418 | fn provided_kind( | |
419 | &mut self, | |
420 | param: &ty::GenericParamDef, | |
421 | arg: &GenericArg<'_>, | |
422 | ) -> subst::GenericArg<'tcx> { | |
423 | let tcx = self.astconv.tcx(); | |
a2a8927a XL |
424 | |
425 | let mut handle_ty_args = |has_default, ty: &hir::Ty<'_>| { | |
426 | if has_default { | |
427 | tcx.check_optional_stability( | |
428 | param.def_id, | |
429 | Some(arg.id()), | |
430 | arg.span(), | |
431 | None, | |
923072b8 | 432 | AllowUnstable::No, |
a2a8927a XL |
433 | |_, _| { |
434 | // Default generic parameters may not be marked | |
435 | // with stability attributes, i.e. when the | |
436 | // default parameter was defined at the same time | |
437 | // as the rest of the type. As such, we ignore missing | |
438 | // stability attributes. | |
439 | }, | |
440 | ) | |
441 | } | |
442 | if let (hir::TyKind::Infer, false) = (&ty.kind, self.astconv.allow_ty_infer()) { | |
443 | self.inferred_params.push(ty.span); | |
444 | tcx.ty_error().into() | |
445 | } else { | |
446 | self.astconv.ast_ty_to_ty(ty).into() | |
447 | } | |
448 | }; | |
449 | ||
fc512014 XL |
450 | match (¶m.kind, arg) { |
451 | (GenericParamDefKind::Lifetime, GenericArg::Lifetime(lt)) => { | |
c295e0f8 | 452 | self.astconv.ast_region_to_region(lt, Some(param)).into() |
fc512014 XL |
453 | } |
454 | (&GenericParamDefKind::Type { has_default, .. }, GenericArg::Type(ty)) => { | |
a2a8927a XL |
455 | handle_ty_args(has_default, ty) |
456 | } | |
457 | (&GenericParamDefKind::Type { has_default, .. }, GenericArg::Infer(inf)) => { | |
458 | handle_ty_args(has_default, &inf.to_ty()) | |
fc512014 | 459 | } |
cdc7bbd5 | 460 | (GenericParamDefKind::Const { .. }, GenericArg::Const(ct)) => { |
fc512014 XL |
461 | ty::Const::from_opt_const_arg_anon_const( |
462 | tcx, | |
463 | ty::WithOptConstParam { | |
464 | did: tcx.hir().local_def_id(ct.value.hir_id), | |
465 | const_param_did: Some(param.def_id), | |
1b1a35ee XL |
466 | }, |
467 | ) | |
fc512014 | 468 | .into() |
1b1a35ee | 469 | } |
a2a8927a XL |
470 | (&GenericParamDefKind::Const { .. }, hir::GenericArg::Infer(inf)) => { |
471 | let ty = tcx.at(self.span).type_of(param.def_id); | |
94222f64 | 472 | if self.astconv.allow_ty_infer() { |
a2a8927a | 473 | self.astconv.ct_infer(ty, Some(param), inf.span).into() |
94222f64 XL |
474 | } else { |
475 | self.inferred_params.push(inf.span); | |
a2a8927a | 476 | tcx.const_error(ty).into() |
94222f64 XL |
477 | } |
478 | } | |
fc512014 | 479 | _ => unreachable!(), |
dfeec247 | 480 | } |
fc512014 XL |
481 | } |
482 | ||
483 | fn inferred_kind( | |
484 | &mut self, | |
485 | substs: Option<&[subst::GenericArg<'tcx>]>, | |
486 | param: &ty::GenericParamDef, | |
487 | infer_args: bool, | |
488 | ) -> subst::GenericArg<'tcx> { | |
489 | let tcx = self.astconv.tcx(); | |
b7449926 | 490 | match param.kind { |
5099ac24 FG |
491 | GenericParamDefKind::Lifetime => self |
492 | .astconv | |
493 | .re_infer(Some(param), self.span) | |
494 | .unwrap_or_else(|| { | |
495 | debug!(?param, "unelided lifetime in signature"); | |
496 | ||
497 | // This indicates an illegal lifetime in a non-assoc-trait position | |
498 | tcx.sess.delay_span_bug(self.span, "unelided lifetime in signature"); | |
499 | ||
500 | // Supply some dummy value. We don't have an | |
501 | // `re_error`, annoyingly, so use `'static`. | |
502 | tcx.lifetimes.re_static | |
503 | }) | |
504 | .into(), | |
b7449926 | 505 | GenericParamDefKind::Type { has_default, .. } => { |
dc9dc135 | 506 | if !infer_args && has_default { |
b7449926 XL |
507 | // No type parameter provided, but a default exists. |
508 | ||
509 | // If we are converting an object type, then the | |
510 | // `Self` parameter is unknown. However, some of the | |
511 | // other type parameters may reference `Self` in their | |
512 | // defaults. This will lead to an ICE if we are not | |
513 | // careful! | |
fc512014 XL |
514 | if self.default_needs_object_self(param) { |
515 | self.missing_type_params.push(param.name.to_string()); | |
f035d41b | 516 | tcx.ty_error().into() |
b7449926 XL |
517 | } else { |
518 | // This is a default type parameter. | |
94222f64 XL |
519 | let substs = substs.unwrap(); |
520 | if substs.iter().any(|arg| match arg.unpack() { | |
521 | GenericArgKind::Type(ty) => ty.references_error(), | |
522 | _ => false, | |
523 | }) { | |
524 | // Avoid ICE #86756 when type error recovery goes awry. | |
525 | return tcx.ty_error().into(); | |
526 | } | |
fc512014 XL |
527 | self.astconv |
528 | .normalize_ty( | |
529 | self.span, | |
04454e1e FG |
530 | EarlyBinder(tcx.at(self.span).type_of(param.def_id)) |
531 | .subst(tcx, substs), | |
fc512014 XL |
532 | ) |
533 | .into() | |
b7449926 | 534 | } |
dc9dc135 | 535 | } else if infer_args { |
b7449926 | 536 | // No type parameters were provided, we can infer all. |
fc512014 XL |
537 | let param = if !self.default_needs_object_self(param) { |
538 | Some(param) | |
539 | } else { | |
540 | None | |
541 | }; | |
542 | self.astconv.ty_infer(param, self.span).into() | |
94b46f34 | 543 | } else { |
b7449926 | 544 | // We've already errored above about the mismatch. |
f035d41b | 545 | tcx.ty_error().into() |
94b46f34 | 546 | } |
94b46f34 | 547 | } |
cdc7bbd5 | 548 | GenericParamDefKind::Const { has_default } => { |
fc512014 | 549 | let ty = tcx.at(self.span).type_of(param.def_id); |
cdc7bbd5 | 550 | if !infer_args && has_default { |
04454e1e FG |
551 | EarlyBinder(tcx.const_param_default(param.def_id)) |
552 | .subst(tcx, substs.unwrap()) | |
cdc7bbd5 | 553 | .into() |
dc9dc135 | 554 | } else { |
cdc7bbd5 XL |
555 | if infer_args { |
556 | self.astconv.ct_infer(ty, Some(param), self.span).into() | |
557 | } else { | |
558 | // We've already errored above about the mismatch. | |
559 | tcx.const_error(ty).into() | |
560 | } | |
dc9dc135 | 561 | } |
532ac7d7 | 562 | } |
a7813a04 | 563 | } |
fc512014 XL |
564 | } |
565 | } | |
566 | ||
567 | let mut substs_ctx = SubstsForAstPathCtxt { | |
568 | astconv: self, | |
569 | def_id, | |
570 | span, | |
571 | generic_args, | |
572 | missing_type_params: vec![], | |
573 | inferred_params: vec![], | |
574 | infer_args, | |
575 | is_object, | |
576 | }; | |
577 | let substs = Self::create_substs_for_generic_args( | |
578 | tcx, | |
579 | def_id, | |
580 | parent_substs, | |
581 | self_ty.is_some(), | |
582 | self_ty, | |
cdc7bbd5 | 583 | &arg_count, |
fc512014 | 584 | &mut substs_ctx, |
b7449926 | 585 | ); |
1a4d82fc | 586 | |
dfeec247 | 587 | self.complain_about_missing_type_params( |
fc512014 | 588 | substs_ctx.missing_type_params, |
dfeec247 XL |
589 | def_id, |
590 | span, | |
591 | generic_args.args.is_empty(), | |
592 | ); | |
593 | ||
cdc7bbd5 XL |
594 | debug!( |
595 | "create_substs_for_ast_path(generic_params={:?}, self_ty={:?}) -> {:?}", | |
596 | generics, self_ty, substs | |
597 | ); | |
598 | ||
599 | (substs, arg_count) | |
600 | } | |
601 | ||
602 | fn create_assoc_bindings_for_generic_args<'a>( | |
603 | &self, | |
604 | generic_args: &'a hir::GenericArgs<'_>, | |
605 | ) -> Vec<ConvertedBinding<'a, 'tcx>> { | |
dc9dc135 XL |
606 | // Convert associated-type bindings or constraints into a separate vector. |
607 | // Example: Given this: | |
608 | // | |
609 | // T: Iterator<Item = u32> | |
610 | // | |
611 | // The `T` is passed in as a self-type; the `Item = u32` is | |
612 | // not a "type parameter" of the `Iterator` trait, but rather | |
613 | // a restriction on `<T as Iterator>::Item`, so it is passed | |
614 | // back separately. | |
dfeec247 XL |
615 | let assoc_bindings = generic_args |
616 | .bindings | |
617 | .iter() | |
dc9dc135 XL |
618 | .map(|binding| { |
619 | let kind = match binding.kind { | |
5099ac24 FG |
620 | hir::TypeBindingKind::Equality { ref term } => match term { |
621 | hir::Term::Ty(ref ty) => { | |
622 | ConvertedBindingKind::Equality(self.ast_ty_to_ty(ty).into()) | |
623 | } | |
624 | hir::Term::Const(ref c) => { | |
625 | let local_did = self.tcx().hir().local_def_id(c.hir_id); | |
626 | let c = Const::from_anon_const(self.tcx(), local_did); | |
627 | ConvertedBindingKind::Equality(c.into()) | |
628 | } | |
629 | }, | |
630 | hir::TypeBindingKind::Constraint { ref bounds } => { | |
dfeec247 XL |
631 | ConvertedBindingKind::Constraint(bounds) |
632 | } | |
dc9dc135 | 633 | }; |
5869c6ff | 634 | ConvertedBinding { |
17df50a5 | 635 | hir_id: binding.hir_id, |
5869c6ff XL |
636 | item_name: binding.ident, |
637 | kind, | |
638 | gen_args: binding.gen_args, | |
639 | span: binding.span, | |
640 | } | |
dc9dc135 XL |
641 | }) |
642 | .collect(); | |
a7813a04 | 643 | |
cdc7bbd5 | 644 | assoc_bindings |
e9174d1e | 645 | } |
e9174d1e | 646 | |
923072b8 | 647 | pub(crate) fn create_substs_for_associated_item( |
dfeec247 XL |
648 | &self, |
649 | tcx: TyCtxt<'tcx>, | |
650 | span: Span, | |
651 | item_def_id: DefId, | |
652 | item_segment: &hir::PathSegment<'_>, | |
653 | parent_substs: SubstsRef<'tcx>, | |
654 | ) -> SubstsRef<'tcx> { | |
17df50a5 XL |
655 | debug!( |
656 | "create_substs_for_associated_item(span: {:?}, item_def_id: {:?}, item_segment: {:?}", | |
657 | span, item_def_id, item_segment | |
658 | ); | |
dfeec247 | 659 | if tcx.generics_of(item_def_id).params.is_empty() { |
923072b8 | 660 | self.prohibit_generics(slice::from_ref(item_segment).iter(), |_| {}); |
dfeec247 XL |
661 | |
662 | parent_substs | |
663 | } else { | |
664 | self.create_substs_for_ast_path( | |
665 | span, | |
666 | item_def_id, | |
667 | parent_substs, | |
5869c6ff XL |
668 | item_segment, |
669 | item_segment.args(), | |
dfeec247 XL |
670 | item_segment.infer_args, |
671 | None, | |
672 | ) | |
673 | .0 | |
674 | } | |
675 | } | |
676 | ||
a7813a04 | 677 | /// Instantiates the path for the given trait reference, assuming that it's |
dc9dc135 | 678 | /// bound to a valid trait type. Returns the `DefId` of the defining trait. |
0531ce1d | 679 | /// The type _cannot_ be a type other than a trait type. |
a7813a04 | 680 | /// |
9fa01778 | 681 | /// If the `projections` argument is `None`, then assoc type bindings like `Foo<T = X>` |
a7813a04 | 682 | /// are disallowed. Otherwise, they are pushed onto the vector given. |
dfeec247 XL |
683 | pub fn instantiate_mono_trait_ref( |
684 | &self, | |
685 | trait_ref: &hir::TraitRef<'_>, | |
686 | self_ty: Ty<'tcx>, | |
687 | ) -> ty::TraitRef<'tcx> { | |
923072b8 | 688 | self.prohibit_generics(trait_ref.path.segments.split_last().unwrap().1.iter(), |_| {}); |
7cac9316 | 689 | |
dfeec247 XL |
690 | self.ast_path_to_mono_trait_ref( |
691 | trait_ref.path.span, | |
ba9703b0 | 692 | trait_ref.trait_def_id().unwrap_or_else(|| FatalError.raise()), |
dfeec247 XL |
693 | self_ty, |
694 | trait_ref.path.segments.last().unwrap(), | |
5099ac24 | 695 | true, |
dfeec247 | 696 | ) |
1a4d82fc | 697 | } |
c34b1796 | 698 | |
c295e0f8 XL |
699 | fn instantiate_poly_trait_ref_inner( |
700 | &self, | |
701 | hir_id: hir::HirId, | |
702 | span: Span, | |
703 | binding_span: Option<Span>, | |
704 | constness: ty::BoundConstness, | |
705 | bounds: &mut Bounds<'tcx>, | |
706 | speculative: bool, | |
707 | trait_ref_span: Span, | |
708 | trait_def_id: DefId, | |
709 | trait_segment: &hir::PathSegment<'_>, | |
710 | args: &GenericArgs<'_>, | |
711 | infer_args: bool, | |
712 | self_ty: Ty<'tcx>, | |
713 | ) -> GenericArgCountResult { | |
714 | let (substs, arg_count) = self.create_substs_for_ast_path( | |
715 | trait_ref_span, | |
716 | trait_def_id, | |
717 | &[], | |
718 | trait_segment, | |
719 | args, | |
720 | infer_args, | |
721 | Some(self_ty), | |
722 | ); | |
723 | ||
724 | let tcx = self.tcx(); | |
725 | let bound_vars = tcx.late_bound_vars(hir_id); | |
726 | debug!(?bound_vars); | |
727 | ||
728 | let assoc_bindings = self.create_assoc_bindings_for_generic_args(args); | |
729 | ||
730 | let poly_trait_ref = | |
731 | ty::Binder::bind_with_vars(ty::TraitRef::new(trait_def_id, substs), bound_vars); | |
732 | ||
733 | debug!(?poly_trait_ref, ?assoc_bindings); | |
734 | bounds.trait_bounds.push((poly_trait_ref, span, constness)); | |
735 | ||
736 | let mut dup_bindings = FxHashMap::default(); | |
737 | for binding in &assoc_bindings { | |
738 | // Specify type to assert that error was already reported in `Err` case. | |
5e7ed085 | 739 | let _: Result<_, ErrorGuaranteed> = self.add_predicates_for_ast_type_binding( |
c295e0f8 XL |
740 | hir_id, |
741 | poly_trait_ref, | |
742 | binding, | |
743 | bounds, | |
744 | speculative, | |
745 | &mut dup_bindings, | |
746 | binding_span.unwrap_or(binding.span), | |
747 | ); | |
5e7ed085 | 748 | // Okay to ignore `Err` because of `ErrorGuaranteed` (see above). |
c295e0f8 XL |
749 | } |
750 | ||
751 | arg_count | |
752 | } | |
753 | ||
cdc7bbd5 XL |
754 | /// Given a trait bound like `Debug`, applies that trait bound the given self-type to construct |
755 | /// a full trait reference. The resulting trait reference is returned. This may also generate | |
756 | /// auxiliary bounds, which are added to `bounds`. | |
757 | /// | |
758 | /// Example: | |
759 | /// | |
04454e1e | 760 | /// ```ignore (illustrative) |
cdc7bbd5 XL |
761 | /// poly_trait_ref = Iterator<Item = u32> |
762 | /// self_ty = Foo | |
763 | /// ``` | |
764 | /// | |
765 | /// this would return `Foo: Iterator` and add `<Foo as Iterator>::Item = u32` into `bounds`. | |
766 | /// | |
767 | /// **A note on binders:** against our usual convention, there is an implied bounder around | |
768 | /// the `self_ty` and `poly_trait_ref` parameters here. So they may reference bound regions. | |
769 | /// If for example you had `for<'a> Foo<'a>: Bar<'a>`, then the `self_ty` would be `Foo<'a>` | |
770 | /// where `'a` is a bound region at depth 0. Similarly, the `poly_trait_ref` would be | |
771 | /// `Bar<'a>`. The returned poly-trait-ref will have this binder instantiated explicitly, | |
772 | /// however. | |
773 | #[tracing::instrument(level = "debug", skip(self, span, constness, bounds, speculative))] | |
c295e0f8 | 774 | pub(crate) fn instantiate_poly_trait_ref( |
dfeec247 XL |
775 | &self, |
776 | trait_ref: &hir::TraitRef<'_>, | |
416331ca | 777 | span: Span, |
94222f64 | 778 | constness: ty::BoundConstness, |
9e0c209e | 779 | self_ty: Ty<'tcx>, |
dc9dc135 XL |
780 | bounds: &mut Bounds<'tcx>, |
781 | speculative: bool, | |
f9f354fc | 782 | ) -> GenericArgCountResult { |
c295e0f8 XL |
783 | let hir_id = trait_ref.hir_ref_id; |
784 | let binding_span = None; | |
785 | let trait_ref_span = trait_ref.path.span; | |
ba9703b0 | 786 | let trait_def_id = trait_ref.trait_def_id().unwrap_or_else(|| FatalError.raise()); |
c295e0f8 XL |
787 | let trait_segment = trait_ref.path.segments.last().unwrap(); |
788 | let args = trait_segment.args(); | |
789 | let infer_args = trait_segment.infer_args; | |
32a655c1 | 790 | |
923072b8 | 791 | self.prohibit_generics(trait_ref.path.segments.split_last().unwrap().1.iter(), |_| {}); |
5099ac24 | 792 | self.complain_about_internal_fn_trait(span, trait_def_id, trait_segment, false); |
7cac9316 | 793 | |
c295e0f8 XL |
794 | self.instantiate_poly_trait_ref_inner( |
795 | hir_id, | |
796 | span, | |
797 | binding_span, | |
798 | constness, | |
799 | bounds, | |
800 | speculative, | |
801 | trait_ref_span, | |
a1dfa0c6 | 802 | trait_def_id, |
c295e0f8 XL |
803 | trait_segment, |
804 | args, | |
805 | infer_args, | |
a1dfa0c6 | 806 | self_ty, |
c295e0f8 | 807 | ) |
c34b1796 AL |
808 | } |
809 | ||
c295e0f8 | 810 | pub(crate) fn instantiate_lang_item_trait_ref( |
3dfed10e XL |
811 | &self, |
812 | lang_item: hir::LangItem, | |
813 | span: Span, | |
814 | hir_id: hir::HirId, | |
815 | args: &GenericArgs<'_>, | |
816 | self_ty: Ty<'tcx>, | |
817 | bounds: &mut Bounds<'tcx>, | |
818 | ) { | |
c295e0f8 XL |
819 | let binding_span = Some(span); |
820 | let constness = ty::BoundConstness::NotConst; | |
821 | let speculative = false; | |
822 | let trait_ref_span = span; | |
3dfed10e | 823 | let trait_def_id = self.tcx().require_lang_item(lang_item, Some(span)); |
c295e0f8 XL |
824 | let trait_segment = &hir::PathSegment::invalid(); |
825 | let infer_args = false; | |
3dfed10e | 826 | |
c295e0f8 XL |
827 | self.instantiate_poly_trait_ref_inner( |
828 | hir_id, | |
5869c6ff | 829 | span, |
c295e0f8 XL |
830 | binding_span, |
831 | constness, | |
832 | bounds, | |
833 | speculative, | |
834 | trait_ref_span, | |
5869c6ff | 835 | trait_def_id, |
c295e0f8 | 836 | trait_segment, |
5869c6ff | 837 | args, |
c295e0f8 XL |
838 | infer_args, |
839 | self_ty, | |
5869c6ff | 840 | ); |
3dfed10e XL |
841 | } |
842 | ||
dfeec247 XL |
843 | fn ast_path_to_mono_trait_ref( |
844 | &self, | |
dc9dc135 XL |
845 | span: Span, |
846 | trait_def_id: DefId, | |
847 | self_ty: Ty<'tcx>, | |
dfeec247 | 848 | trait_segment: &hir::PathSegment<'_>, |
5099ac24 | 849 | is_impl: bool, |
dfeec247 | 850 | ) -> ty::TraitRef<'tcx> { |
5099ac24 FG |
851 | let (substs, _) = self.create_substs_for_ast_trait_ref( |
852 | span, | |
853 | trait_def_id, | |
854 | self_ty, | |
855 | trait_segment, | |
856 | is_impl, | |
857 | ); | |
cdc7bbd5 | 858 | let assoc_bindings = self.create_assoc_bindings_for_generic_args(trait_segment.args()); |
f9f354fc | 859 | if let Some(b) = assoc_bindings.first() { |
3dfed10e | 860 | Self::prohibit_assoc_ty_binding(self.tcx(), b.span); |
f9f354fc | 861 | } |
a7813a04 XL |
862 | ty::TraitRef::new(trait_def_id, substs) |
863 | } | |
c34b1796 | 864 | |
cdc7bbd5 | 865 | #[tracing::instrument(level = "debug", skip(self, span))] |
dfeec247 XL |
866 | fn create_substs_for_ast_trait_ref<'a>( |
867 | &self, | |
868 | span: Span, | |
869 | trait_def_id: DefId, | |
870 | self_ty: Ty<'tcx>, | |
871 | trait_segment: &'a hir::PathSegment<'a>, | |
5099ac24 | 872 | is_impl: bool, |
cdc7bbd5 | 873 | ) -> (SubstsRef<'tcx>, GenericArgCountResult) { |
5099ac24 | 874 | self.complain_about_internal_fn_trait(span, trait_def_id, trait_segment, is_impl); |
dfeec247 XL |
875 | |
876 | self.create_substs_for_ast_path( | |
877 | span, | |
878 | trait_def_id, | |
879 | &[], | |
5869c6ff XL |
880 | trait_segment, |
881 | trait_segment.args(), | |
dfeec247 XL |
882 | trait_segment.infer_args, |
883 | Some(self_ty), | |
884 | ) | |
a7813a04 | 885 | } |
1a4d82fc | 886 | |
f9f354fc | 887 | fn trait_defines_associated_type_named(&self, trait_def_id: DefId, assoc_name: Ident) -> bool { |
74b04a01 XL |
888 | self.tcx() |
889 | .associated_items(trait_def_id) | |
890 | .find_by_name_and_kind(self.tcx(), assoc_name, ty::AssocKind::Type, trait_def_id) | |
891 | .is_some() | |
476ff2be | 892 | } |
5099ac24 FG |
893 | fn trait_defines_associated_const_named(&self, trait_def_id: DefId, assoc_name: Ident) -> bool { |
894 | self.tcx() | |
895 | .associated_items(trait_def_id) | |
896 | .find_by_name_and_kind(self.tcx(), assoc_name, ty::AssocKind::Const, trait_def_id) | |
897 | .is_some() | |
898 | } | |
476ff2be | 899 | |
c295e0f8 XL |
900 | // Sets `implicitly_sized` to true on `Bounds` if necessary |
901 | pub(crate) fn add_implicitly_sized<'hir>( | |
902 | &self, | |
903 | bounds: &mut Bounds<'hir>, | |
904 | ast_bounds: &'hir [hir::GenericBound<'hir>], | |
905 | self_ty_where_predicates: Option<(hir::HirId, &'hir [hir::WherePredicate<'hir>])>, | |
906 | span: Span, | |
907 | ) { | |
dc9dc135 XL |
908 | let tcx = self.tcx(); |
909 | ||
910 | // Try to find an unbound in bounds. | |
911 | let mut unbound = None; | |
c295e0f8 XL |
912 | let mut search_bounds = |ast_bounds: &'hir [hir::GenericBound<'hir>]| { |
913 | for ab in ast_bounds { | |
914 | if let hir::GenericBound::Trait(ptr, hir::TraitBoundModifier::Maybe) = ab { | |
915 | if unbound.is_none() { | |
916 | unbound = Some(&ptr.trait_ref); | |
917 | } else { | |
918 | tcx.sess.emit_err(MultipleRelaxedDefaultBounds { span }); | |
919 | } | |
dc9dc135 XL |
920 | } |
921 | } | |
c295e0f8 XL |
922 | }; |
923 | search_bounds(ast_bounds); | |
924 | if let Some((self_ty, where_clause)) = self_ty_where_predicates { | |
925 | let self_ty_def_id = tcx.hir().local_def_id(self_ty).to_def_id(); | |
926 | for clause in where_clause { | |
927 | if let hir::WherePredicate::BoundPredicate(pred) = clause { | |
04454e1e FG |
928 | if pred.is_param_bound(self_ty_def_id) { |
929 | search_bounds(pred.bounds); | |
dc9dc135 XL |
930 | } |
931 | } | |
932 | } | |
c295e0f8 XL |
933 | } |
934 | ||
935 | let sized_def_id = tcx.lang_items().require(LangItem::Sized); | |
936 | match (&sized_def_id, unbound) { | |
937 | (Ok(sized_def_id), Some(tpb)) | |
938 | if tpb.path.res == Res::Def(DefKind::Trait, *sized_def_id) => | |
939 | { | |
940 | // There was in fact a `?Sized` bound, return without doing anything | |
941 | return; | |
dc9dc135 | 942 | } |
c295e0f8 XL |
943 | (_, Some(_)) => { |
944 | // There was a `?Trait` bound, but it was not `?Sized`; warn. | |
945 | tcx.sess.span_warn( | |
946 | span, | |
947 | "default bound relaxed for a type parameter, but \ | |
948 | this does nothing because the given bound is not \ | |
949 | a default; only `?Sized` is supported", | |
950 | ); | |
951 | // Otherwise, add implicitly sized if `Sized` is available. | |
952 | } | |
953 | _ => { | |
954 | // There was no `?Sized` bound; add implicitly sized if `Sized` is available. | |
955 | } | |
956 | } | |
957 | if sized_def_id.is_err() { | |
dc9dc135 | 958 | // No lang item for `Sized`, so we can't add it as a bound. |
c295e0f8 | 959 | return; |
dc9dc135 | 960 | } |
c295e0f8 | 961 | bounds.implicitly_sized = Some(span); |
dc9dc135 XL |
962 | } |
963 | ||
964 | /// This helper takes a *converted* parameter type (`param_ty`) | |
965 | /// and an *unconverted* list of bounds: | |
966 | /// | |
ba9703b0 | 967 | /// ```text |
dc9dc135 XL |
968 | /// fn foo<T: Debug> |
969 | /// ^ ^^^^^ `ast_bounds` parameter, in HIR form | |
970 | /// | | |
971 | /// `param_ty`, in ty form | |
972 | /// ``` | |
973 | /// | |
974 | /// It adds these `ast_bounds` into the `bounds` structure. | |
975 | /// | |
976 | /// **A note on binders:** there is an implied binder around | |
977 | /// `param_ty` and `ast_bounds`. See `instantiate_poly_trait_ref` | |
978 | /// for more details. | |
c295e0f8 XL |
979 | #[tracing::instrument(level = "debug", skip(self, ast_bounds, bounds))] |
980 | pub(crate) fn add_bounds<'hir, I: Iterator<Item = &'hir hir::GenericBound<'hir>>>( | |
dfeec247 | 981 | &self, |
dc9dc135 | 982 | param_ty: Ty<'tcx>, |
c295e0f8 | 983 | ast_bounds: I, |
dc9dc135 | 984 | bounds: &mut Bounds<'tcx>, |
cdc7bbd5 | 985 | bound_vars: &'tcx ty::List<ty::BoundVariableKind>, |
dc9dc135 | 986 | ) { |
dc9dc135 | 987 | for ast_bound in ast_bounds { |
c295e0f8 XL |
988 | match ast_bound { |
989 | hir::GenericBound::Trait(poly_trait_ref, modifier) => { | |
990 | let constness = match modifier { | |
991 | hir::TraitBoundModifier::MaybeConst => ty::BoundConstness::ConstIfConst, | |
992 | hir::TraitBoundModifier::None => ty::BoundConstness::NotConst, | |
993 | hir::TraitBoundModifier::Maybe => continue, | |
994 | }; | |
995 | ||
996 | let _ = self.instantiate_poly_trait_ref( | |
997 | &poly_trait_ref.trait_ref, | |
998 | poly_trait_ref.span, | |
999 | constness, | |
cdc7bbd5 XL |
1000 | param_ty, |
1001 | bounds, | |
1002 | false, | |
1003 | ); | |
dfeec247 | 1004 | } |
c295e0f8 XL |
1005 | &hir::GenericBound::LangItemTrait(lang_item, span, hir_id, args) => { |
1006 | self.instantiate_lang_item_trait_ref( | |
1007 | lang_item, span, hir_id, args, param_ty, bounds, | |
cdc7bbd5 | 1008 | ); |
dfeec247 | 1009 | } |
c295e0f8 XL |
1010 | hir::GenericBound::Outlives(lifetime) => { |
1011 | let region = self.ast_region_to_region(lifetime, None); | |
1012 | bounds | |
1013 | .region_bounds | |
1014 | .push((ty::Binder::bind_with_vars(region, bound_vars), lifetime.span)); | |
1015 | } | |
dc9dc135 XL |
1016 | } |
1017 | } | |
dc9dc135 XL |
1018 | } |
1019 | ||
1020 | /// Translates a list of bounds from the HIR into the `Bounds` data structure. | |
1021 | /// The self-type for the bounds is given by `param_ty`. | |
1022 | /// | |
1023 | /// Example: | |
1024 | /// | |
04454e1e | 1025 | /// ```ignore (illustrative) |
dc9dc135 | 1026 | /// fn foo<T: Bar + Baz>() { } |
04454e1e FG |
1027 | /// // ^ ^^^^^^^^^ ast_bounds |
1028 | /// // param_ty | |
dc9dc135 XL |
1029 | /// ``` |
1030 | /// | |
1031 | /// The `sized_by_default` parameter indicates if, in this context, the `param_ty` should be | |
1032 | /// considered `Sized` unless there is an explicit `?Sized` bound. This would be true in the | |
1033 | /// example above, but is not true in supertrait listings like `trait Foo: Bar + Baz`. | |
1034 | /// | |
1035 | /// `span` should be the declaration size of the parameter. | |
c295e0f8 | 1036 | pub(crate) fn compute_bounds( |
dfeec247 | 1037 | &self, |
dc9dc135 | 1038 | param_ty: Ty<'tcx>, |
dfeec247 | 1039 | ast_bounds: &[hir::GenericBound<'_>], |
6a06907d | 1040 | ) -> Bounds<'tcx> { |
c295e0f8 | 1041 | self.compute_bounds_inner(param_ty, ast_bounds) |
6a06907d XL |
1042 | } |
1043 | ||
1044 | /// Convert the bounds in `ast_bounds` that refer to traits which define an associated type | |
1045 | /// named `assoc_name` into ty::Bounds. Ignore the rest. | |
c295e0f8 | 1046 | pub(crate) fn compute_bounds_that_match_assoc_type( |
6a06907d XL |
1047 | &self, |
1048 | param_ty: Ty<'tcx>, | |
1049 | ast_bounds: &[hir::GenericBound<'_>], | |
6a06907d XL |
1050 | assoc_name: Ident, |
1051 | ) -> Bounds<'tcx> { | |
1052 | let mut result = Vec::new(); | |
1053 | ||
1054 | for ast_bound in ast_bounds { | |
5e7ed085 FG |
1055 | if let Some(trait_ref) = ast_bound.trait_ref() |
1056 | && let Some(trait_did) = trait_ref.trait_def_id() | |
1057 | && self.tcx().trait_may_define_assoc_type(trait_did, assoc_name) | |
1058 | { | |
1059 | result.push(ast_bound.clone()); | |
6a06907d XL |
1060 | } |
1061 | } | |
1062 | ||
c295e0f8 | 1063 | self.compute_bounds_inner(param_ty, &result) |
6a06907d XL |
1064 | } |
1065 | ||
1066 | fn compute_bounds_inner( | |
1067 | &self, | |
1068 | param_ty: Ty<'tcx>, | |
cdc7bbd5 | 1069 | ast_bounds: &[hir::GenericBound<'_>], |
dc9dc135 XL |
1070 | ) -> Bounds<'tcx> { |
1071 | let mut bounds = Bounds::default(); | |
1072 | ||
c295e0f8 | 1073 | self.add_bounds(param_ty, ast_bounds.iter(), &mut bounds, ty::List::empty()); |
04454e1e | 1074 | debug!(?bounds); |
dc9dc135 XL |
1075 | |
1076 | bounds | |
1077 | } | |
1078 | ||
1079 | /// Given an HIR binding like `Item = Foo` or `Item: Foo`, pushes the corresponding predicates | |
1080 | /// onto `bounds`. | |
1081 | /// | |
1082 | /// **A note on binders:** given something like `T: for<'a> Iterator<Item = &'a u32>`, the | |
1083 | /// `trait_ref` here will be `for<'a> T: Iterator`. The `binding` data however is from *inside* | |
1084 | /// the binder (e.g., `&'a u32`) and hence may reference bound regions. | |
cdc7bbd5 XL |
1085 | #[tracing::instrument( |
1086 | level = "debug", | |
1087 | skip(self, bounds, speculative, dup_bindings, path_span) | |
1088 | )] | |
dc9dc135 | 1089 | fn add_predicates_for_ast_type_binding( |
a7813a04 | 1090 | &self, |
532ac7d7 | 1091 | hir_ref_id: hir::HirId, |
9e0c209e | 1092 | trait_ref: ty::PolyTraitRef<'tcx>, |
dc9dc135 XL |
1093 | binding: &ConvertedBinding<'_, 'tcx>, |
1094 | bounds: &mut Bounds<'tcx>, | |
94b46f34 | 1095 | speculative: bool, |
dc9dc135 | 1096 | dup_bindings: &mut FxHashMap<DefId, Span>, |
dfeec247 | 1097 | path_span: Span, |
5e7ed085 | 1098 | ) -> Result<(), ErrorGuaranteed> { |
5869c6ff XL |
1099 | // Given something like `U: SomeTrait<T = X>`, we want to produce a |
1100 | // predicate like `<U as SomeTrait>::T = X`. This is somewhat | |
1101 | // subtle in the event that `T` is defined in a supertrait of | |
1102 | // `SomeTrait`, because in that case we need to upcast. | |
1103 | // | |
1104 | // That is, consider this case: | |
1105 | // | |
1106 | // ``` | |
1107 | // trait SubTrait: SuperTrait<i32> { } | |
1108 | // trait SuperTrait<A> { type T; } | |
1109 | // | |
1110 | // ... B: SubTrait<T = foo> ... | |
1111 | // ``` | |
1112 | // | |
1113 | // We want to produce `<B as SuperTrait<i32>>::T == foo`. | |
3dfed10e | 1114 | |
5869c6ff | 1115 | let tcx = self.tcx(); |
a7813a04 | 1116 | |
dfeec247 XL |
1117 | let candidate = |
1118 | if self.trait_defines_associated_type_named(trait_ref.def_id(), binding.item_name) { | |
1119 | // Simple case: X is defined in the current trait. | |
1120 | trait_ref | |
1121 | } else { | |
1122 | // Otherwise, we have to walk through the supertraits to find | |
1123 | // those that do. | |
1124 | self.one_bound_for_assoc_type( | |
1125 | || traits::supertraits(tcx, trait_ref), | |
1126 | || trait_ref.print_only_trait_path().to_string(), | |
1127 | binding.item_name, | |
1128 | path_span, | |
1129 | || match binding.kind { | |
1130 | ConvertedBindingKind::Equality(ty) => Some(ty.to_string()), | |
1131 | _ => None, | |
1132 | }, | |
1133 | )? | |
1134 | }; | |
ff7c6d11 | 1135 | |
94b46f34 | 1136 | let (assoc_ident, def_scope) = |
dc9dc135 | 1137 | tcx.adjust_ident_and_get_scope(binding.item_name, candidate.def_id(), hir_ref_id); |
74b04a01 | 1138 | |
ba9703b0 | 1139 | // We have already adjusted the item name above, so compare with `ident.normalize_to_macros_2_0()` instead |
74b04a01 | 1140 | // of calling `filter_by_name_and_kind`. |
5099ac24 FG |
1141 | let find_item_of_kind = |kind| { |
1142 | tcx.associated_items(candidate.def_id()) | |
1143 | .filter_by_name_unhygienic(assoc_ident.name) | |
1144 | .find(|i| i.kind == kind && i.ident(tcx).normalize_to_macros_2_0() == assoc_ident) | |
1145 | }; | |
1146 | let assoc_item = find_item_of_kind(ty::AssocKind::Type) | |
1147 | .or_else(|| find_item_of_kind(ty::AssocKind::Const)) | |
dfeec247 | 1148 | .expect("missing associated type"); |
ff7c6d11 | 1149 | |
5099ac24 FG |
1150 | if !assoc_item.vis.is_accessible_from(def_scope, tcx) { |
1151 | let kind = match assoc_item.kind { | |
1152 | ty::AssocKind::Type => "type", | |
1153 | ty::AssocKind::Const => "const", | |
1154 | _ => unreachable!(), | |
1155 | }; | |
ba9703b0 XL |
1156 | tcx.sess |
1157 | .struct_span_err( | |
1158 | binding.span, | |
5099ac24 | 1159 | &format!("associated {kind} `{}` is private", binding.item_name), |
ba9703b0 | 1160 | ) |
5099ac24 | 1161 | .span_label(binding.span, &format!("private associated {kind}")) |
ba9703b0 | 1162 | .emit(); |
a7813a04 | 1163 | } |
5099ac24 | 1164 | tcx.check_stability(assoc_item.def_id, Some(hir_ref_id), binding.span, None); |
a7813a04 | 1165 | |
94b46f34 | 1166 | if !speculative { |
dfeec247 | 1167 | dup_bindings |
5099ac24 | 1168 | .entry(assoc_item.def_id) |
94b46f34 | 1169 | .and_modify(|prev_span| { |
1b1a35ee XL |
1170 | self.tcx().sess.emit_err(ValueOfAssociatedStructAlreadySpecified { |
1171 | span: binding.span, | |
1172 | prev_span: *prev_span, | |
1173 | item_name: binding.item_name, | |
5099ac24 | 1174 | def_path: tcx.def_path_str(assoc_item.container.id()), |
1b1a35ee | 1175 | }); |
94b46f34 XL |
1176 | }) |
1177 | .or_insert(binding.span); | |
1178 | } | |
1179 | ||
5869c6ff XL |
1180 | // Include substitutions for generic parameters of associated types |
1181 | let projection_ty = candidate.map_bound(|trait_ref| { | |
5099ac24 | 1182 | let ident = Ident::new(assoc_item.name, binding.item_name.span); |
5869c6ff | 1183 | let item_segment = hir::PathSegment { |
17df50a5 XL |
1184 | ident, |
1185 | hir_id: Some(binding.hir_id), | |
5869c6ff XL |
1186 | res: None, |
1187 | args: Some(binding.gen_args), | |
1188 | infer_args: false, | |
1189 | }; | |
1190 | ||
1191 | let substs_trait_ref_and_assoc_item = self.create_substs_for_associated_item( | |
1192 | tcx, | |
1193 | path_span, | |
5099ac24 | 1194 | assoc_item.def_id, |
5869c6ff XL |
1195 | &item_segment, |
1196 | trait_ref.substs, | |
1197 | ); | |
1198 | ||
1199 | debug!( | |
1200 | "add_predicates_for_ast_type_binding: substs for trait-ref and assoc_item: {:?}", | |
1201 | substs_trait_ref_and_assoc_item | |
1202 | ); | |
1203 | ||
1204 | ty::ProjectionTy { | |
5099ac24 | 1205 | item_def_id: assoc_item.def_id, |
5869c6ff XL |
1206 | substs: substs_trait_ref_and_assoc_item, |
1207 | } | |
1208 | }); | |
1209 | ||
1210 | if !speculative { | |
1211 | // Find any late-bound regions declared in `ty` that are not | |
5099ac24 | 1212 | // declared in the trait-ref or assoc_item. These are not well-formed. |
5869c6ff XL |
1213 | // |
1214 | // Example: | |
1215 | // | |
1216 | // for<'a> <T as Iterator>::Item = &'a str // <-- 'a is bad | |
1217 | // for<'a> <T as FnMut<(&'a u32,)>>::Output = &'a str // <-- 'a is ok | |
1218 | if let ConvertedBindingKind::Equality(ty) = binding.kind { | |
1219 | let late_bound_in_trait_ref = | |
1220 | tcx.collect_constrained_late_bound_regions(&projection_ty); | |
1221 | let late_bound_in_ty = | |
cdc7bbd5 | 1222 | tcx.collect_referenced_late_bound_regions(&trait_ref.rebind(ty)); |
5869c6ff XL |
1223 | debug!("late_bound_in_trait_ref = {:?}", late_bound_in_trait_ref); |
1224 | debug!("late_bound_in_ty = {:?}", late_bound_in_ty); | |
1225 | ||
1226 | // FIXME: point at the type params that don't have appropriate lifetimes: | |
1227 | // struct S1<F: for<'a> Fn(&i32, &i32) -> &'a i32>(F); | |
1228 | // ---- ---- ^^^^^^^ | |
1229 | self.validate_late_bound_regions( | |
1230 | late_bound_in_trait_ref, | |
1231 | late_bound_in_ty, | |
1232 | |br_name| { | |
1233 | struct_span_err!( | |
1234 | tcx.sess, | |
1235 | binding.span, | |
1236 | E0582, | |
1237 | "binding for associated type `{}` references {}, \ | |
1238 | which does not appear in the trait input types", | |
1239 | binding.item_name, | |
1240 | br_name | |
1241 | ) | |
1242 | }, | |
1243 | ); | |
1244 | } | |
1245 | } | |
1246 | ||
dc9dc135 | 1247 | match binding.kind { |
5099ac24 | 1248 | ConvertedBindingKind::Equality(term) => { |
dc9dc135 XL |
1249 | // "Desugar" a constraint like `T: Iterator<Item = u32>` this to |
1250 | // the "projection predicate" for: | |
1251 | // | |
1252 | // `<T as Iterator>::Item = u32` | |
5099ac24 FG |
1253 | let assoc_item_def_id = projection_ty.skip_binder().item_def_id; |
1254 | let def_kind = tcx.def_kind(assoc_item_def_id); | |
1255 | match (def_kind, term) { | |
1256 | (hir::def::DefKind::AssocTy, ty::Term::Ty(_)) | |
1257 | | (hir::def::DefKind::AssocConst, ty::Term::Const(_)) => (), | |
1258 | (_, _) => { | |
1259 | let got = if let ty::Term::Ty(_) = term { "type" } else { "const" }; | |
1260 | let expected = def_kind.descr(assoc_item_def_id); | |
1261 | tcx.sess | |
1262 | .struct_span_err( | |
1263 | binding.span, | |
1264 | &format!("mismatch in bind of {expected}, got {got}"), | |
1265 | ) | |
1266 | .span_note( | |
1267 | tcx.def_span(assoc_item_def_id), | |
1268 | &format!("{expected} defined here does not match {got}"), | |
1269 | ) | |
1270 | .emit(); | |
1271 | } | |
1272 | } | |
dfeec247 | 1273 | bounds.projection_bounds.push(( |
5099ac24 FG |
1274 | projection_ty.map_bound(|projection_ty| ty::ProjectionPredicate { |
1275 | projection_ty, | |
1276 | term: term, | |
dfeec247 XL |
1277 | }), |
1278 | binding.span, | |
1279 | )); | |
9e0c209e | 1280 | } |
dc9dc135 XL |
1281 | ConvertedBindingKind::Constraint(ast_bounds) => { |
1282 | // "Desugar" a constraint like `T: Iterator<Item: Debug>` to | |
1283 | // | |
1284 | // `<T as Iterator>::Item: Debug` | |
1285 | // | |
1286 | // Calling `skip_binder` is okay, because `add_bounds` expects the `param_ty` | |
1287 | // parameter to have a skipped binder. | |
cdc7bbd5 | 1288 | let param_ty = tcx.mk_ty(ty::Projection(projection_ty.skip_binder())); |
c295e0f8 | 1289 | self.add_bounds(param_ty, ast_bounds.iter(), bounds, candidate.bound_vars()); |
dc9dc135 XL |
1290 | } |
1291 | } | |
1292 | Ok(()) | |
1a4d82fc JJ |
1293 | } |
1294 | ||
dfeec247 XL |
1295 | fn ast_path_to_ty( |
1296 | &self, | |
a7813a04 | 1297 | span: Span, |
a7813a04 | 1298 | did: DefId, |
dfeec247 XL |
1299 | item_segment: &hir::PathSegment<'_>, |
1300 | ) -> Ty<'tcx> { | |
32a655c1 | 1301 | let substs = self.ast_path_substs_for_ty(span, did, item_segment); |
04454e1e FG |
1302 | self.normalize_ty( |
1303 | span, | |
1304 | EarlyBinder(self.tcx().at(span).type_of(did)).subst(self.tcx(), substs), | |
1305 | ) | |
1a4d82fc JJ |
1306 | } |
1307 | ||
dfeec247 XL |
1308 | fn conv_object_ty_poly_trait_ref( |
1309 | &self, | |
32a655c1 | 1310 | span: Span, |
dfeec247 XL |
1311 | trait_bounds: &[hir::PolyTraitRef<'_>], |
1312 | lifetime: &hir::Lifetime, | |
3dfed10e | 1313 | borrowed: bool, |
dfeec247 | 1314 | ) -> Ty<'tcx> { |
a7813a04 | 1315 | let tcx = self.tcx(); |
9e0c209e | 1316 | |
dc9dc135 XL |
1317 | let mut bounds = Bounds::default(); |
1318 | let mut potential_assoc_types = Vec::new(); | |
532ac7d7 | 1319 | let dummy_self = self.tcx().types.trait_object_dummy_self; |
416331ca | 1320 | for trait_bound in trait_bounds.iter().rev() { |
f9f354fc XL |
1321 | if let GenericArgCountResult { |
1322 | correct: | |
1323 | Err(GenericArgCountMismatch { invalid_args: cur_potential_assoc_types, .. }), | |
1324 | .. | |
1325 | } = self.instantiate_poly_trait_ref( | |
cdc7bbd5 XL |
1326 | &trait_bound.trait_ref, |
1327 | trait_bound.span, | |
94222f64 | 1328 | ty::BoundConstness::NotConst, |
416331ca XL |
1329 | dummy_self, |
1330 | &mut bounds, | |
cdc7bbd5 | 1331 | false, |
74b04a01 | 1332 | ) { |
5869c6ff | 1333 | potential_assoc_types.extend(cur_potential_assoc_types); |
74b04a01 | 1334 | } |
416331ca | 1335 | } |
dc9dc135 XL |
1336 | |
1337 | // Expand trait aliases recursively and check that only one regular (non-auto) trait | |
1338 | // is used and no 'maybe' bounds are used. | |
74b04a01 XL |
1339 | let expanded_traits = |
1340 | traits::expand_trait_aliases(tcx, bounds.trait_bounds.iter().map(|&(a, b, _)| (a, b))); | |
04454e1e FG |
1341 | let (mut auto_traits, regular_traits): (Vec<_>, Vec<_>) = expanded_traits |
1342 | .filter(|i| i.trait_ref().self_ty().skip_binder() == dummy_self) | |
1343 | .partition(|i| tcx.trait_is_auto(i.trait_ref().def_id())); | |
dc9dc135 XL |
1344 | if regular_traits.len() > 1 { |
1345 | let first_trait = ®ular_traits[0]; | |
1346 | let additional_trait = ®ular_traits[1]; | |
dfeec247 XL |
1347 | let mut err = struct_span_err!( |
1348 | tcx.sess, | |
1349 | additional_trait.bottom().1, | |
1350 | E0225, | |
dc9dc135 XL |
1351 | "only auto traits can be used as additional traits in a trait object" |
1352 | ); | |
dfeec247 XL |
1353 | additional_trait.label_with_exp_info( |
1354 | &mut err, | |
1355 | "additional non-auto trait", | |
1356 | "additional use", | |
1357 | ); | |
1358 | first_trait.label_with_exp_info(&mut err, "first non-auto trait", "first use"); | |
3dfed10e | 1359 | err.help(&format!( |
c295e0f8 | 1360 | "consider creating a new trait with all of these as supertraits and using that \ |
3dfed10e XL |
1361 | trait here instead: `trait NewTrait: {} {{}}`", |
1362 | regular_traits | |
1363 | .iter() | |
1364 | .map(|t| t.trait_ref().print_only_trait_path().to_string()) | |
1365 | .collect::<Vec<_>>() | |
1366 | .join(" + "), | |
1367 | )); | |
1368 | err.note( | |
1369 | "auto-traits like `Send` and `Sync` are traits that have special properties; \ | |
1370 | for more information on them, visit \ | |
1371 | <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits>", | |
1372 | ); | |
dc9dc135 | 1373 | err.emit(); |
7cac9316 XL |
1374 | } |
1375 | ||
dc9dc135 | 1376 | if regular_traits.is_empty() && auto_traits.is_empty() { |
04454e1e FG |
1377 | let trait_alias_span = bounds |
1378 | .trait_bounds | |
1379 | .iter() | |
1380 | .map(|&(trait_ref, _, _)| trait_ref.def_id()) | |
1381 | .find(|&trait_ref| tcx.is_trait_alias(trait_ref)) | |
1382 | .map(|trait_ref| tcx.def_span(trait_ref)); | |
1383 | tcx.sess.emit_err(TraitObjectDeclaredWithNoTraits { span, trait_alias_span }); | |
f035d41b | 1384 | return tcx.ty_error(); |
9e0c209e SL |
1385 | } |
1386 | ||
a1dfa0c6 XL |
1387 | // Check that there are no gross object safety violations; |
1388 | // most importantly, that the supertraits don't contain `Self`, | |
1389 | // to avoid ICEs. | |
dc9dc135 XL |
1390 | for item in ®ular_traits { |
1391 | let object_safety_violations = | |
dfeec247 | 1392 | astconv_object_safety_violations(tcx, item.trait_ref().def_id()); |
dc9dc135 | 1393 | if !object_safety_violations.is_empty() { |
dfeec247 XL |
1394 | report_object_safety_error( |
1395 | tcx, | |
dc9dc135 XL |
1396 | span, |
1397 | item.trait_ref().def_id(), | |
a2a8927a | 1398 | &object_safety_violations, |
dfeec247 XL |
1399 | ) |
1400 | .emit(); | |
f035d41b | 1401 | return tcx.ty_error(); |
dc9dc135 | 1402 | } |
a7813a04 XL |
1403 | } |
1404 | ||
a1dfa0c6 | 1405 | // Use a `BTreeSet` to keep output in a more consistent order. |
dfeec247 | 1406 | let mut associated_types: FxHashMap<Span, BTreeSet<DefId>> = FxHashMap::default(); |
b7449926 | 1407 | |
dfeec247 XL |
1408 | let regular_traits_refs_spans = bounds |
1409 | .trait_bounds | |
dc9dc135 | 1410 | .into_iter() |
dfeec247 | 1411 | .filter(|(trait_ref, _, _)| !tcx.trait_is_auto(trait_ref.def_id())); |
a7813a04 | 1412 | |
dfeec247 | 1413 | for (base_trait_ref, span, constness) in regular_traits_refs_spans { |
94222f64 | 1414 | assert_eq!(constness, ty::BoundConstness::NotConst); |
a7813a04 | 1415 | |
ba9703b0 | 1416 | for obligation in traits::elaborate_trait_ref(tcx, base_trait_ref) { |
dfeec247 XL |
1417 | debug!( |
1418 | "conv_object_ty_poly_trait_ref: observing object predicate `{:?}`", | |
ba9703b0 | 1419 | obligation.predicate |
a1dfa0c6 | 1420 | ); |
3dfed10e | 1421 | |
5869c6ff | 1422 | let bound_predicate = obligation.predicate.kind(); |
29967ef6 | 1423 | match bound_predicate.skip_binder() { |
94222f64 | 1424 | ty::PredicateKind::Trait(pred) => { |
29967ef6 | 1425 | let pred = bound_predicate.rebind(pred); |
dfeec247 XL |
1426 | associated_types.entry(span).or_default().extend( |
1427 | tcx.associated_items(pred.def_id()) | |
74b04a01 | 1428 | .in_definition_order() |
dfeec247 XL |
1429 | .filter(|item| item.kind == ty::AssocKind::Type) |
1430 | .map(|item| item.def_id), | |
1431 | ); | |
1432 | } | |
5869c6ff | 1433 | ty::PredicateKind::Projection(pred) => { |
29967ef6 | 1434 | let pred = bound_predicate.rebind(pred); |
dfeec247 XL |
1435 | // A `Self` within the original bound will be substituted with a |
1436 | // `trait_object_dummy_self`, so check for that. | |
5099ac24 FG |
1437 | let references_self = match pred.skip_binder().term { |
1438 | ty::Term::Ty(ty) => ty.walk().any(|arg| arg == dummy_self.into()), | |
1439 | ty::Term::Const(c) => c.ty().walk().any(|arg| arg == dummy_self.into()), | |
1440 | }; | |
dfeec247 XL |
1441 | |
1442 | // If the projection output contains `Self`, force the user to | |
1443 | // elaborate it explicitly to avoid a lot of complexity. | |
1444 | // | |
5e7ed085 | 1445 | // The "classically useful" case is the following: |
dfeec247 XL |
1446 | // ``` |
1447 | // trait MyTrait: FnMut() -> <Self as MyTrait>::MyOutput { | |
1448 | // type MyOutput; | |
1449 | // } | |
1450 | // ``` | |
1451 | // | |
1452 | // Here, the user could theoretically write `dyn MyTrait<Output = X>`, | |
1453 | // but actually supporting that would "expand" to an infinitely-long type | |
1454 | // `fix $ τ → dyn MyTrait<MyOutput = X, Output = <τ as MyTrait>::MyOutput`. | |
1455 | // | |
1456 | // Instead, we force the user to write | |
1457 | // `dyn MyTrait<MyOutput = X, Output = X>`, which is uglier but works. See | |
1458 | // the discussion in #56288 for alternatives. | |
1459 | if !references_self { | |
1460 | // Include projections defined on supertraits. | |
1461 | bounds.projection_bounds.push((pred, span)); | |
1462 | } | |
a1dfa0c6 | 1463 | } |
dfeec247 | 1464 | _ => (), |
a1dfa0c6 XL |
1465 | } |
1466 | } | |
dfeec247 XL |
1467 | } |
1468 | ||
1469 | for (projection_bound, _) in &bounds.projection_bounds { | |
74b04a01 | 1470 | for def_ids in associated_types.values_mut() { |
dfeec247 | 1471 | def_ids.remove(&projection_bound.projection_def_id()); |
a1dfa0c6 | 1472 | } |
a7813a04 | 1473 | } |
9346a6ac | 1474 | |
dfeec247 XL |
1475 | self.complain_about_missing_associated_types( |
1476 | associated_types, | |
1477 | potential_assoc_types, | |
1478 | trait_bounds, | |
1479 | ); | |
1480 | ||
dc9dc135 XL |
1481 | // De-duplicate auto traits so that, e.g., `dyn Trait + Send + Send` is the same as |
1482 | // `dyn Trait + Send`. | |
6a06907d XL |
1483 | // We remove duplicates by inserting into a `FxHashSet` to avoid re-ordering |
1484 | // the bounds | |
1485 | let mut duplicates = FxHashSet::default(); | |
1486 | auto_traits.retain(|i| duplicates.insert(i.trait_ref().def_id())); | |
dc9dc135 XL |
1487 | debug!("regular_traits: {:?}", regular_traits); |
1488 | debug!("auto_traits: {:?}", auto_traits); | |
1489 | ||
532ac7d7 | 1490 | // Erase the `dummy_self` (`trait_object_dummy_self`) used above. |
6a06907d XL |
1491 | let existential_trait_refs = regular_traits.iter().map(|i| { |
1492 | i.trait_ref().map_bound(|trait_ref: ty::TraitRef<'tcx>| { | |
1493 | if trait_ref.self_ty() != dummy_self { | |
1494 | // FIXME: There appears to be a missing filter on top of `expand_trait_aliases`, | |
1495 | // which picks up non-supertraits where clauses - but also, the object safety | |
1496 | // completely ignores trait aliases, which could be object safety hazards. We | |
1497 | // `delay_span_bug` here to avoid an ICE in stable even when the feature is | |
1498 | // disabled. (#66420) | |
1499 | tcx.sess.delay_span_bug( | |
1500 | DUMMY_SP, | |
1501 | &format!( | |
1502 | "trait_ref_to_existential called on {:?} with non-dummy Self", | |
1503 | trait_ref, | |
1504 | ), | |
1505 | ); | |
1506 | } | |
1507 | ty::ExistentialTraitRef::erase_self_ty(tcx, trait_ref) | |
1508 | }) | |
1509 | }); | |
dc9dc135 | 1510 | let existential_projections = bounds.projection_bounds.iter().map(|(bound, _)| { |
a1dfa0c6 | 1511 | bound.map_bound(|b| { |
6a06907d XL |
1512 | if b.projection_ty.self_ty() != dummy_self { |
1513 | tcx.sess.delay_span_bug( | |
1514 | DUMMY_SP, | |
1515 | &format!("trait_ref_to_existential called on {:?} with non-dummy Self", b), | |
1516 | ); | |
a1dfa0c6 | 1517 | } |
6a06907d | 1518 | ty::ExistentialProjection::erase_self_ty(tcx, b) |
a1dfa0c6 XL |
1519 | }) |
1520 | }); | |
1521 | ||
5869c6ff XL |
1522 | let regular_trait_predicates = existential_trait_refs |
1523 | .map(|trait_ref| trait_ref.map_bound(ty::ExistentialPredicate::Trait)); | |
fc512014 XL |
1524 | let auto_trait_predicates = auto_traits.into_iter().map(|trait_ref| { |
1525 | ty::Binder::dummy(ty::ExistentialPredicate::AutoTrait(trait_ref.trait_ref().def_id())) | |
1526 | }); | |
17df50a5 XL |
1527 | // N.b. principal, projections, auto traits |
1528 | // FIXME: This is actually wrong with multiple principals in regards to symbol mangling | |
dfeec247 | 1529 | let mut v = regular_trait_predicates |
dfeec247 | 1530 | .chain( |
5869c6ff | 1531 | existential_projections.map(|x| x.map_bound(ty::ExistentialPredicate::Projection)), |
dfeec247 | 1532 | ) |
17df50a5 | 1533 | .chain(auto_trait_predicates) |
b7449926 | 1534 | .collect::<SmallVec<[_; 8]>>(); |
fc512014 | 1535 | v.sort_by(|a, b| a.skip_binder().stable_cmp(tcx, &b.skip_binder())); |
0731742a | 1536 | v.dedup(); |
fc512014 | 1537 | let existential_predicates = tcx.mk_poly_existential_predicates(v.into_iter()); |
476ff2be | 1538 | |
a1dfa0c6 | 1539 | // Use explicitly-specified region bound. |
32a655c1 SL |
1540 | let region_bound = if !lifetime.is_elided() { |
1541 | self.ast_region_to_region(lifetime, None) | |
1542 | } else { | |
1543 | self.compute_object_lifetime_bound(span, existential_predicates).unwrap_or_else(|| { | |
9fa01778 | 1544 | if tcx.named_region(lifetime.hir_id).is_some() { |
32a655c1 SL |
1545 | self.ast_region_to_region(lifetime, None) |
1546 | } else { | |
dc9dc135 | 1547 | self.re_infer(None, span).unwrap_or_else(|| { |
3dfed10e | 1548 | let mut err = struct_span_err!( |
dfeec247 XL |
1549 | tcx.sess, |
1550 | span, | |
1551 | E0228, | |
dc9dc135 | 1552 | "the lifetime bound for this object type cannot be deduced \ |
dfeec247 | 1553 | from context; please supply an explicit bound" |
3dfed10e XL |
1554 | ); |
1555 | if borrowed { | |
1556 | // We will have already emitted an error E0106 complaining about a | |
1557 | // missing named lifetime in `&dyn Trait`, so we elide this one. | |
1558 | err.delay_as_bug(); | |
1559 | } else { | |
1560 | err.emit(); | |
1561 | } | |
48663c56 | 1562 | tcx.lifetimes.re_static |
32a655c1 SL |
1563 | }) |
1564 | } | |
1565 | }) | |
476ff2be | 1566 | }; |
476ff2be SL |
1567 | debug!("region_bound: {:?}", region_bound); |
1568 | ||
1569 | let ty = tcx.mk_dynamic(existential_predicates, region_bound); | |
9e0c209e SL |
1570 | debug!("trait_object_type: {:?}", ty); |
1571 | ty | |
9346a6ac AL |
1572 | } |
1573 | ||
48663c56 XL |
1574 | fn report_ambiguous_associated_type( |
1575 | &self, | |
1576 | span: Span, | |
1577 | type_str: &str, | |
1578 | trait_str: &str, | |
f9f354fc | 1579 | name: Symbol, |
5e7ed085 | 1580 | ) -> ErrorGuaranteed { |
48663c56 | 1581 | let mut err = struct_span_err!(self.tcx().sess, span, E0223, "ambiguous associated type"); |
923072b8 FG |
1582 | if self |
1583 | .tcx() | |
1584 | .resolutions(()) | |
1585 | .confused_type_with_std_module | |
1586 | .keys() | |
1587 | .any(|full_span| full_span.contains(span)) | |
1588 | { | |
48663c56 | 1589 | err.span_suggestion( |
923072b8 | 1590 | span.shrink_to_lo(), |
48663c56 | 1591 | "you are looking for the module in `std`, not the primitive type", |
923072b8 | 1592 | "std::", |
48663c56 XL |
1593 | Applicability::MachineApplicable, |
1594 | ); | |
1595 | } else { | |
1596 | err.span_suggestion( | |
dfeec247 XL |
1597 | span, |
1598 | "use fully-qualified syntax", | |
1599 | format!("<{} as {}>::{}", type_str, trait_str, name), | |
1600 | Applicability::HasPlaceholders, | |
48663c56 XL |
1601 | ); |
1602 | } | |
5e7ed085 | 1603 | err.emit() |
a7813a04 | 1604 | } |
9346a6ac | 1605 | |
a7813a04 | 1606 | // Search for a bound on a type parameter which includes the associated item |
dc9dc135 | 1607 | // given by `assoc_name`. `ty_param_def_id` is the `DefId` of the type parameter |
8bb4bdeb | 1608 | // This function will fail if there are no suitable bounds or there is |
a7813a04 | 1609 | // any ambiguity. |
dfeec247 XL |
1610 | fn find_bound_for_assoc_item( |
1611 | &self, | |
f9f354fc XL |
1612 | ty_param_def_id: LocalDefId, |
1613 | assoc_name: Ident, | |
dfeec247 | 1614 | span: Span, |
5e7ed085 | 1615 | ) -> Result<ty::PolyTraitRef<'tcx>, ErrorGuaranteed> { |
a7813a04 | 1616 | let tcx = self.tcx(); |
c34b1796 | 1617 | |
416331ca XL |
1618 | debug!( |
1619 | "find_bound_for_assoc_item(ty_param_def_id={:?}, assoc_name={:?}, span={:?})", | |
dfeec247 | 1620 | ty_param_def_id, assoc_name, span, |
416331ca XL |
1621 | ); |
1622 | ||
6a06907d XL |
1623 | let predicates = &self |
1624 | .get_type_parameter_bounds(span, ty_param_def_id.to_def_id(), assoc_name) | |
1625 | .predicates; | |
416331ca XL |
1626 | |
1627 | debug!("find_bound_for_assoc_item: predicates={:#?}", predicates); | |
1628 | ||
04454e1e | 1629 | let param_name = tcx.hir().ty_param_name(ty_param_def_id); |
dfeec247 XL |
1630 | self.one_bound_for_assoc_type( |
1631 | || { | |
6a06907d | 1632 | traits::transitive_bounds_that_define_assoc_type( |
dfeec247 | 1633 | tcx, |
fc512014 | 1634 | predicates.iter().filter_map(|(p, _)| { |
a2a8927a | 1635 | Some(p.to_opt_poly_trait_pred()?.map_bound(|t| t.trait_ref)) |
fc512014 | 1636 | }), |
6a06907d | 1637 | assoc_name, |
dfeec247 XL |
1638 | ) |
1639 | }, | |
1640 | || param_name.to_string(), | |
1641 | assoc_name, | |
1642 | span, | |
1643 | || None, | |
1644 | ) | |
9346a6ac AL |
1645 | } |
1646 | ||
a1dfa0c6 | 1647 | // Checks that `bounds` contains exactly one element and reports appropriate |
a7813a04 | 1648 | // errors otherwise. |
dfeec247 XL |
1649 | fn one_bound_for_assoc_type<I>( |
1650 | &self, | |
1651 | all_candidates: impl Fn() -> I, | |
1652 | ty_param_name: impl Fn() -> String, | |
f9f354fc | 1653 | assoc_name: Ident, |
dfeec247 XL |
1654 | span: Span, |
1655 | is_equality: impl Fn() -> Option<String>, | |
5e7ed085 | 1656 | ) -> Result<ty::PolyTraitRef<'tcx>, ErrorGuaranteed> |
dfeec247 XL |
1657 | where |
1658 | I: Iterator<Item = ty::PolyTraitRef<'tcx>>, | |
a7813a04 | 1659 | { |
dfeec247 XL |
1660 | let mut matching_candidates = all_candidates() |
1661 | .filter(|r| self.trait_defines_associated_type_named(r.def_id(), assoc_name)); | |
5099ac24 FG |
1662 | let mut const_candidates = all_candidates() |
1663 | .filter(|r| self.trait_defines_associated_const_named(r.def_id(), assoc_name)); | |
dfeec247 | 1664 | |
5099ac24 FG |
1665 | let (bound, next_cand) = match (matching_candidates.next(), const_candidates.next()) { |
1666 | (Some(bound), _) => (bound, matching_candidates.next()), | |
1667 | (None, Some(bound)) => (bound, const_candidates.next()), | |
1668 | (None, None) => { | |
5e7ed085 | 1669 | let reported = self.complain_about_assoc_type_not_found( |
dfeec247 XL |
1670 | all_candidates, |
1671 | &ty_param_name(), | |
1672 | assoc_name, | |
1673 | span, | |
1674 | ); | |
5e7ed085 | 1675 | return Err(reported); |
476ff2be SL |
1676 | } |
1677 | }; | |
416331ca XL |
1678 | debug!("one_bound_for_assoc_type: bound = {:?}", bound); |
1679 | ||
5099ac24 | 1680 | if let Some(bound2) = next_cand { |
416331ca XL |
1681 | debug!("one_bound_for_assoc_type: bound2 = {:?}", bound2); |
1682 | ||
dfeec247 | 1683 | let is_equality = is_equality(); |
a2a8927a | 1684 | let bounds = IntoIterator::into_iter([bound, bound2]).chain(matching_candidates); |
dfeec247 XL |
1685 | let mut err = if is_equality.is_some() { |
1686 | // More specific Error Index entry. | |
1687 | struct_span_err!( | |
1688 | self.tcx().sess, | |
1689 | span, | |
1690 | E0222, | |
1691 | "ambiguous associated type `{}` in bounds of `{}`", | |
1692 | assoc_name, | |
1693 | ty_param_name() | |
1694 | ) | |
1695 | } else { | |
1696 | struct_span_err!( | |
1697 | self.tcx().sess, | |
1698 | span, | |
1699 | E0221, | |
1700 | "ambiguous associated type `{}` in bounds of `{}`", | |
1701 | assoc_name, | |
1702 | ty_param_name() | |
1703 | ) | |
1704 | }; | |
7cac9316 | 1705 | err.span_label(span, format!("ambiguous associated type `{}`", assoc_name)); |
9346a6ac | 1706 | |
dfeec247 | 1707 | let mut where_bounds = vec![]; |
476ff2be | 1708 | for bound in bounds { |
74b04a01 | 1709 | let bound_id = bound.def_id(); |
dfeec247 XL |
1710 | let bound_span = self |
1711 | .tcx() | |
74b04a01 XL |
1712 | .associated_items(bound_id) |
1713 | .find_by_name_and_kind(self.tcx(), assoc_name, ty::AssocKind::Type, bound_id) | |
416331ca | 1714 | .and_then(|item| self.tcx().hir().span_if_local(item.def_id)); |
476ff2be | 1715 | |
dfeec247 XL |
1716 | if let Some(bound_span) = bound_span { |
1717 | err.span_label( | |
1718 | bound_span, | |
1719 | format!( | |
1720 | "ambiguous `{}` from `{}`", | |
1721 | assoc_name, | |
1722 | bound.print_only_trait_path(), | |
1723 | ), | |
1724 | ); | |
1725 | if let Some(constraint) = &is_equality { | |
1726 | where_bounds.push(format!( | |
1727 | " T: {trait}::{assoc} = {constraint}", | |
1728 | trait=bound.print_only_trait_path(), | |
1729 | assoc=assoc_name, | |
1730 | constraint=constraint, | |
1731 | )); | |
1732 | } else { | |
c295e0f8 XL |
1733 | err.span_suggestion_verbose( |
1734 | span.with_hi(assoc_name.span.lo()), | |
dfeec247 XL |
1735 | "use fully qualified syntax to disambiguate", |
1736 | format!( | |
c295e0f8 | 1737 | "<{} as {}>::", |
dfeec247 XL |
1738 | ty_param_name(), |
1739 | bound.print_only_trait_path(), | |
dfeec247 XL |
1740 | ), |
1741 | Applicability::MaybeIncorrect, | |
1742 | ); | |
1743 | } | |
c30ab7b3 | 1744 | } else { |
dfeec247 XL |
1745 | err.note(&format!( |
1746 | "associated type `{}` could derive from `{}`", | |
1747 | ty_param_name(), | |
1748 | bound.print_only_trait_path(), | |
1749 | )); | |
c30ab7b3 | 1750 | } |
a7813a04 | 1751 | } |
dfeec247 XL |
1752 | if !where_bounds.is_empty() { |
1753 | err.help(&format!( | |
1754 | "consider introducing a new type parameter `T` and adding `where` constraints:\ | |
1755 | \n where\n T: {},\n{}", | |
1756 | ty_param_name(), | |
1757 | where_bounds.join(",\n"), | |
1758 | )); | |
1759 | } | |
5e7ed085 | 1760 | let reported = err.emit(); |
dfeec247 | 1761 | if !where_bounds.is_empty() { |
5e7ed085 | 1762 | return Err(reported); |
dfeec247 | 1763 | } |
9346a6ac | 1764 | } |
5099ac24 | 1765 | |
ba9703b0 | 1766 | Ok(bound) |
9346a6ac AL |
1767 | } |
1768 | ||
a7813a04 | 1769 | // Create a type from a path to an associated type. |
9fa01778 | 1770 | // For a path `A::B::C::D`, `qself_ty` and `qself_def` are the type and def for `A::B::C` |
a1dfa0c6 | 1771 | // and item_segment is the path segment for `D`. We return a type and a def for |
a7813a04 | 1772 | // the whole path. |
9fa01778 | 1773 | // Will fail except for `T::A` and `Self::A`; i.e., if `qself_ty`/`qself_def` are not a type |
a1dfa0c6 | 1774 | // parameter or `Self`. |
6a06907d | 1775 | // NOTE: When this function starts resolving `Trait::AssocTy` successfully |
5e7ed085 | 1776 | // it should also start reporting the `BARE_TRAIT_OBJECTS` lint. |
9fa01778 XL |
1777 | pub fn associated_path_to_ty( |
1778 | &self, | |
532ac7d7 | 1779 | hir_ref_id: hir::HirId, |
9fa01778 XL |
1780 | span: Span, |
1781 | qself_ty: Ty<'tcx>, | |
923072b8 | 1782 | qself: &hir::Ty<'_>, |
dfeec247 | 1783 | assoc_segment: &hir::PathSegment<'_>, |
9fa01778 | 1784 | permit_variants: bool, |
5e7ed085 | 1785 | ) -> Result<(Ty<'tcx>, DefKind, DefId), ErrorGuaranteed> { |
a7813a04 | 1786 | let tcx = self.tcx(); |
9fa01778 | 1787 | let assoc_ident = assoc_segment.ident; |
923072b8 FG |
1788 | let qself_res = if let hir::TyKind::Path(hir::QPath::Resolved(_, ref path)) = qself.kind { |
1789 | path.res | |
1790 | } else { | |
1791 | Res::Err | |
1792 | }; | |
a7813a04 | 1793 | |
9fa01778 | 1794 | debug!("associated_path_to_ty: {:?}::{}", qself_ty, assoc_ident); |
a7813a04 | 1795 | |
9fa01778 XL |
1796 | // Check if we have an enum variant. |
1797 | let mut variant_resolution = None; | |
1b1a35ee | 1798 | if let ty::Adt(adt_def, _) = qself_ty.kind() { |
9fa01778 | 1799 | if adt_def.is_enum() { |
dfeec247 | 1800 | let variant_def = adt_def |
5e7ed085 | 1801 | .variants() |
dfeec247 | 1802 | .iter() |
5e7ed085 | 1803 | .find(|vd| tcx.hygienic_eq(assoc_ident, vd.ident(tcx), adt_def.did())); |
9fa01778 | 1804 | if let Some(variant_def) = variant_def { |
9fa01778 | 1805 | if permit_variants { |
17df50a5 | 1806 | tcx.check_stability(variant_def.def_id, Some(hir_ref_id), span, None); |
923072b8 FG |
1807 | self.prohibit_generics(slice::from_ref(assoc_segment).iter(), |err| { |
1808 | err.note("enum variants can't have type parameters"); | |
1809 | let type_name = tcx.item_name(adt_def.did()); | |
1810 | let msg = format!( | |
1811 | "you might have meant to specity type parameters on enum \ | |
1812 | `{type_name}`" | |
1813 | ); | |
1814 | let Some(args) = assoc_segment.args else { return; }; | |
1815 | // Get the span of the generics args *including* the leading `::`. | |
1816 | let args_span = assoc_segment.ident.span.shrink_to_hi().to(args.span_ext); | |
1817 | if tcx.generics_of(adt_def.did()).count() == 0 { | |
1818 | // FIXME(estebank): we could also verify that the arguments being | |
1819 | // work for the `enum`, instead of just looking if it takes *any*. | |
1820 | err.span_suggestion_verbose( | |
1821 | args_span, | |
1822 | &format!("{type_name} doesn't have generic parameters"), | |
1823 | "", | |
1824 | Applicability::MachineApplicable, | |
1825 | ); | |
1826 | return; | |
1827 | } | |
1828 | let Ok(snippet) = tcx.sess.source_map().span_to_snippet(args_span) else { | |
1829 | err.note(&msg); | |
1830 | return; | |
1831 | }; | |
1832 | let (qself_sugg_span, is_self) = if let hir::TyKind::Path( | |
1833 | hir::QPath::Resolved(_, ref path) | |
1834 | ) = qself.kind { | |
1835 | // If the path segment already has type params, we want to overwrite | |
1836 | // them. | |
1837 | match &path.segments[..] { | |
1838 | // `segment` is the previous to last element on the path, | |
1839 | // which would normally be the `enum` itself, while the last | |
1840 | // `_` `PathSegment` corresponds to the variant. | |
1841 | [.., hir::PathSegment { | |
1842 | ident, | |
1843 | args, | |
1844 | res: Some(Res::Def(DefKind::Enum, _)), | |
1845 | .. | |
1846 | }, _] => ( | |
1847 | // We need to include the `::` in `Type::Variant::<Args>` | |
1848 | // to point the span to `::<Args>`, not just `<Args>`. | |
1849 | ident.span.shrink_to_hi().to(args.map_or( | |
1850 | ident.span.shrink_to_hi(), | |
1851 | |a| a.span_ext)), | |
1852 | false, | |
1853 | ), | |
1854 | [segment] => ( | |
1855 | // We need to include the `::` in `Type::Variant::<Args>` | |
1856 | // to point the span to `::<Args>`, not just `<Args>`. | |
1857 | segment.ident.span.shrink_to_hi().to(segment.args.map_or( | |
1858 | segment.ident.span.shrink_to_hi(), | |
1859 | |a| a.span_ext)), | |
1860 | kw::SelfUpper == segment.ident.name, | |
1861 | ), | |
1862 | _ => { | |
1863 | err.note(&msg); | |
1864 | return; | |
1865 | } | |
1866 | } | |
1867 | } else { | |
1868 | err.note(&msg); | |
1869 | return; | |
1870 | }; | |
1871 | let suggestion = vec![ | |
1872 | if is_self { | |
1873 | // Account for people writing `Self::Variant::<Args>`, where | |
1874 | // `Self` is the enum, and suggest replacing `Self` with the | |
1875 | // appropriate type: `Type::<Args>::Variant`. | |
1876 | (qself.span, format!("{type_name}{snippet}")) | |
1877 | } else { | |
1878 | (qself_sugg_span, snippet) | |
1879 | }, | |
1880 | (args_span, String::new()), | |
1881 | ]; | |
1882 | err.multipart_suggestion_verbose( | |
1883 | &msg, | |
1884 | suggestion, | |
1885 | Applicability::MaybeIncorrect, | |
1886 | ); | |
1887 | }); | |
48663c56 | 1888 | return Ok((qself_ty, DefKind::Variant, variant_def.def_id)); |
9fa01778 | 1889 | } else { |
48663c56 | 1890 | variant_resolution = Some(variant_def.def_id); |
9fa01778 XL |
1891 | } |
1892 | } | |
1893 | } | |
1894 | } | |
a7813a04 XL |
1895 | |
1896 | // Find the type of the associated item, and the trait where the associated | |
1897 | // item is declared. | |
1b1a35ee | 1898 | let bound = match (&qself_ty.kind(), qself_res) { |
5099ac24 | 1899 | (_, Res::SelfTy { trait_: Some(_), alias_to: Some((impl_def_id, _)) }) => { |
0731742a | 1900 | // `Self` in an impl of a trait -- we have a concrete self type and a |
a7813a04 | 1901 | // trait reference. |
5e7ed085 FG |
1902 | let Some(trait_ref) = tcx.impl_trait_ref(impl_def_id) else { |
1903 | // A cycle error occurred, most likely. | |
1904 | let guar = tcx.sess.delay_span_bug(span, "expected cycle error"); | |
1905 | return Err(guar); | |
8bb4bdeb XL |
1906 | }; |
1907 | ||
dfeec247 | 1908 | self.one_bound_for_assoc_type( |
136023e0 | 1909 | || traits::supertraits(tcx, ty::Binder::dummy(trait_ref)), |
dfeec247 XL |
1910 | || "Self".to_string(), |
1911 | assoc_ident, | |
1912 | span, | |
1913 | || None, | |
1914 | )? | |
c1a9b12d | 1915 | } |
ba9703b0 XL |
1916 | ( |
1917 | &ty::Param(_), | |
5099ac24 FG |
1918 | Res::SelfTy { trait_: Some(param_did), alias_to: None } |
1919 | | Res::Def(DefKind::TyParam, param_did), | |
f9f354fc | 1920 | ) => self.find_bound_for_assoc_item(param_did.expect_local(), assoc_ident, span)?, |
9fa01778 | 1921 | _ => { |
5e7ed085 | 1922 | let reported = if variant_resolution.is_some() { |
9fa01778 XL |
1923 | // Variant in type position |
1924 | let msg = format!("expected type, found variant `{}`", assoc_ident); | |
5e7ed085 | 1925 | tcx.sess.span_err(span, &msg) |
9fa01778 | 1926 | } else if qself_ty.is_enum() { |
dfeec247 XL |
1927 | let mut err = struct_span_err!( |
1928 | tcx.sess, | |
48663c56 | 1929 | assoc_ident.span, |
dfeec247 XL |
1930 | E0599, |
1931 | "no variant named `{}` found for enum `{}`", | |
1932 | assoc_ident, | |
1933 | qself_ty, | |
a1dfa0c6 | 1934 | ); |
48663c56 | 1935 | |
9fa01778 XL |
1936 | let adt_def = qself_ty.ty_adt_def().expect("enum is not an ADT"); |
1937 | if let Some(suggested_name) = find_best_match_for_name( | |
fc512014 | 1938 | &adt_def |
5e7ed085 | 1939 | .variants() |
fc512014 | 1940 | .iter() |
5099ac24 | 1941 | .map(|variant| variant.name) |
fc512014 | 1942 | .collect::<Vec<Symbol>>(), |
3dfed10e | 1943 | assoc_ident.name, |
9fa01778 XL |
1944 | None, |
1945 | ) { | |
1946 | err.span_suggestion( | |
48663c56 XL |
1947 | assoc_ident.span, |
1948 | "there is a variant with a similar name", | |
923072b8 | 1949 | suggested_name, |
9fa01778 XL |
1950 | Applicability::MaybeIncorrect, |
1951 | ); | |
1952 | } else { | |
416331ca XL |
1953 | err.span_label( |
1954 | assoc_ident.span, | |
1955 | format!("variant not found in `{}`", qself_ty), | |
1956 | ); | |
48663c56 XL |
1957 | } |
1958 | ||
5e7ed085 | 1959 | if let Some(sp) = tcx.hir().span_if_local(adt_def.did()) { |
ba9703b0 | 1960 | let sp = tcx.sess.source_map().guess_head_span(sp); |
48663c56 | 1961 | err.span_label(sp, format!("variant `{}` not found here", assoc_ident)); |
9fa01778 | 1962 | } |
48663c56 | 1963 | |
5e7ed085 FG |
1964 | err.emit() |
1965 | } else if let Some(reported) = qself_ty.error_reported() { | |
1966 | reported | |
1967 | } else { | |
9fa01778 | 1968 | // Don't print `TyErr` to the user. |
48663c56 XL |
1969 | self.report_ambiguous_associated_type( |
1970 | span, | |
1971 | &qself_ty.to_string(), | |
1972 | "Trait", | |
e1599b0c | 1973 | assoc_ident.name, |
5e7ed085 FG |
1974 | ) |
1975 | }; | |
1976 | return Err(reported); | |
9346a6ac | 1977 | } |
a7813a04 | 1978 | }; |
c34b1796 | 1979 | |
83c7162d | 1980 | let trait_did = bound.def_id(); |
dc9dc135 XL |
1981 | let (assoc_ident, def_scope) = |
1982 | tcx.adjust_ident_and_get_scope(assoc_ident, trait_did, hir_ref_id); | |
74b04a01 | 1983 | |
ba9703b0 | 1984 | // We have already adjusted the item name above, so compare with `ident.normalize_to_macros_2_0()` instead |
74b04a01 | 1985 | // of calling `filter_by_name_and_kind`. |
5099ac24 FG |
1986 | let item = tcx.associated_items(trait_did).in_definition_order().find(|i| { |
1987 | i.kind.namespace() == Namespace::TypeNS | |
1988 | && i.ident(tcx).normalize_to_macros_2_0() == assoc_ident | |
1989 | }); | |
1990 | // Assume that if it's not matched, there must be a const defined with the same name | |
1991 | // but it was used in a type position. | |
1992 | let Some(item) = item else { | |
1993 | let msg = format!("found associated const `{assoc_ident}` when type was expected"); | |
5e7ed085 FG |
1994 | let guar = tcx.sess.struct_span_err(span, &msg).emit(); |
1995 | return Err(guar); | |
5099ac24 | 1996 | }; |
041b39d2 | 1997 | |
dfeec247 | 1998 | let ty = self.projected_ty_from_poly_trait_ref(span, item.def_id, assoc_segment, bound); |
041b39d2 XL |
1999 | let ty = self.normalize_ty(span, ty); |
2000 | ||
dc9dc135 | 2001 | let kind = DefKind::AssocTy; |
7cac9316 | 2002 | if !item.vis.is_accessible_from(def_scope, tcx) { |
ba9703b0 XL |
2003 | let kind = kind.descr(item.def_id); |
2004 | let msg = format!("{} `{}` is private", kind, assoc_ident); | |
2005 | tcx.sess | |
2006 | .struct_span_err(span, &msg) | |
2007 | .span_label(span, &format!("private {}", kind)) | |
2008 | .emit(); | |
7cac9316 | 2009 | } |
17df50a5 | 2010 | tcx.check_stability(item.def_id, Some(hir_ref_id), span, None); |
7cac9316 | 2011 | |
48663c56 | 2012 | if let Some(variant_def_id) = variant_resolution { |
74b04a01 XL |
2013 | tcx.struct_span_lint_hir(AMBIGUOUS_ASSOCIATED_ITEMS, hir_ref_id, span, |lint| { |
2014 | let mut err = lint.build("ambiguous associated item"); | |
2015 | let mut could_refer_to = |kind: DefKind, def_id, also| { | |
2016 | let note_msg = format!( | |
2017 | "`{}` could{} refer to the {} defined here", | |
2018 | assoc_ident, | |
2019 | also, | |
2020 | kind.descr(def_id) | |
2021 | ); | |
2022 | err.span_note(tcx.def_span(def_id), ¬e_msg); | |
2023 | }; | |
9fa01778 | 2024 | |
74b04a01 XL |
2025 | could_refer_to(DefKind::Variant, variant_def_id, ""); |
2026 | could_refer_to(kind, item.def_id, " also"); | |
2027 | ||
2028 | err.span_suggestion( | |
2029 | span, | |
2030 | "use fully-qualified syntax", | |
2031 | format!("<{} as {}>::{}", qself_ty, tcx.item_name(trait_did), assoc_ident), | |
2032 | Applicability::MachineApplicable, | |
dfeec247 | 2033 | ); |
9fa01778 | 2034 | |
74b04a01 XL |
2035 | err.emit(); |
2036 | }); | |
9fa01778 | 2037 | } |
48663c56 | 2038 | Ok((ty, kind, item.def_id)) |
a7813a04 | 2039 | } |
1a4d82fc | 2040 | |
dfeec247 XL |
2041 | fn qpath_to_ty( |
2042 | &self, | |
2043 | span: Span, | |
2044 | opt_self_ty: Option<Ty<'tcx>>, | |
2045 | item_def_id: DefId, | |
2046 | trait_segment: &hir::PathSegment<'_>, | |
2047 | item_segment: &hir::PathSegment<'_>, | |
2048 | ) -> Ty<'tcx> { | |
a7813a04 | 2049 | let tcx = self.tcx(); |
60c5eb7d | 2050 | |
04454e1e | 2051 | let trait_def_id = tcx.parent(item_def_id); |
1a4d82fc | 2052 | |
60c5eb7d XL |
2053 | debug!("qpath_to_ty: trait_def_id={:?}", trait_def_id); |
2054 | ||
3c0e092e | 2055 | let Some(self_ty) = opt_self_ty else { |
532ac7d7 | 2056 | let path_str = tcx.def_path_str(trait_def_id); |
60c5eb7d XL |
2057 | |
2058 | let def_id = self.item_def_id(); | |
2059 | ||
2060 | debug!("qpath_to_ty: self.item_def_id()={:?}", def_id); | |
2061 | ||
dfeec247 | 2062 | let parent_def_id = def_id |
f9f354fc | 2063 | .and_then(|def_id| { |
3dfed10e | 2064 | def_id.as_local().map(|def_id| tcx.hir().local_def_id_to_hir_id(def_id)) |
f9f354fc | 2065 | }) |
5099ac24 | 2066 | .map(|hir_id| tcx.hir().get_parent_item(hir_id).to_def_id()); |
60c5eb7d XL |
2067 | |
2068 | debug!("qpath_to_ty: parent_def_id={:?}", parent_def_id); | |
2069 | ||
2070 | // If the trait in segment is the same as the trait defining the item, | |
2071 | // use the `<Self as ..>` syntax in the error. | |
2072 | let is_part_of_self_trait_constraints = def_id == Some(trait_def_id); | |
2073 | let is_part_of_fn_in_self_trait = parent_def_id == Some(trait_def_id); | |
2074 | ||
2075 | let type_name = if is_part_of_self_trait_constraints || is_part_of_fn_in_self_trait { | |
2076 | "Self" | |
2077 | } else { | |
2078 | "Type" | |
2079 | }; | |
2080 | ||
48663c56 XL |
2081 | self.report_ambiguous_associated_type( |
2082 | span, | |
60c5eb7d | 2083 | type_name, |
48663c56 | 2084 | &path_str, |
e1599b0c | 2085 | item_segment.ident.name, |
48663c56 | 2086 | ); |
f035d41b | 2087 | return tcx.ty_error(); |
a7813a04 | 2088 | }; |
1a4d82fc | 2089 | |
a7813a04 | 2090 | debug!("qpath_to_ty: self_type={:?}", self_ty); |
1a4d82fc | 2091 | |
5099ac24 FG |
2092 | let trait_ref = |
2093 | self.ast_path_to_mono_trait_ref(span, trait_def_id, self_ty, trait_segment, false); | |
dfeec247 XL |
2094 | |
2095 | let item_substs = self.create_substs_for_associated_item( | |
2096 | tcx, | |
2097 | span, | |
2098 | item_def_id, | |
2099 | item_segment, | |
2100 | trait_ref.substs, | |
2101 | ); | |
1a4d82fc | 2102 | |
a7813a04 | 2103 | debug!("qpath_to_ty: trait_ref={:?}", trait_ref); |
85aaf69f | 2104 | |
dfeec247 | 2105 | self.normalize_ty(span, tcx.mk_projection(item_def_id, item_substs)) |
8bb4bdeb XL |
2106 | } |
2107 | ||
923072b8 | 2108 | pub fn prohibit_generics<'a>( |
dfeec247 | 2109 | &self, |
923072b8 FG |
2110 | segments: impl Iterator<Item = &'a hir::PathSegment<'a>> + Clone, |
2111 | extend: impl Fn(&mut DiagnosticBuilder<'tcx, ErrorGuaranteed>), | |
dfeec247 | 2112 | ) -> bool { |
923072b8 FG |
2113 | let args = segments.clone().flat_map(|segment| segment.args().args); |
2114 | ||
2115 | let (lt, ty, ct, inf) = | |
2116 | args.clone().fold((false, false, false, false), |(lt, ty, ct, inf), arg| match arg { | |
2117 | hir::GenericArg::Lifetime(_) => (true, ty, ct, inf), | |
2118 | hir::GenericArg::Type(_) => (lt, true, ct, inf), | |
2119 | hir::GenericArg::Const(_) => (lt, ty, true, inf), | |
2120 | hir::GenericArg::Infer(_) => (lt, ty, ct, true), | |
2121 | }); | |
2122 | let mut emitted = false; | |
2123 | if lt || ty || ct || inf { | |
2124 | let types_and_spans: Vec<_> = segments | |
2125 | .clone() | |
2126 | .flat_map(|segment| { | |
2127 | segment.res.and_then(|res| { | |
2128 | if segment.args().args.is_empty() { | |
2129 | None | |
2130 | } else { | |
2131 | Some(( | |
2132 | match res { | |
2133 | Res::PrimTy(ty) => format!("{} `{}`", res.descr(), ty.name()), | |
2134 | Res::Def(_, def_id) | |
2135 | if let Some(name) = self.tcx().opt_item_name(def_id) => { | |
2136 | format!("{} `{name}`", res.descr()) | |
2137 | } | |
2138 | Res::Err => "this type".to_string(), | |
2139 | _ => res.descr().to_string(), | |
2140 | }, | |
2141 | segment.ident.span, | |
2142 | )) | |
94222f64 | 2143 | } |
923072b8 FG |
2144 | }) |
2145 | }) | |
2146 | .collect(); | |
2147 | let this_type = match &types_and_spans[..] { | |
2148 | [.., _, (last, _)] => format!( | |
2149 | "{} and {last}", | |
2150 | types_and_spans[..types_and_spans.len() - 1] | |
2151 | .iter() | |
2152 | .map(|(x, _)| x.as_str()) | |
2153 | .intersperse(&", ") | |
2154 | .collect::<String>() | |
2155 | ), | |
2156 | [(only, _)] => only.to_string(), | |
2157 | [] => "this type".to_string(), | |
2158 | }; | |
2159 | ||
2160 | let arg_spans: Vec<Span> = args.map(|arg| arg.span()).collect(); | |
2161 | ||
2162 | let mut kinds = Vec::with_capacity(4); | |
2163 | if lt { | |
2164 | kinds.push("lifetime"); | |
2165 | } | |
2166 | if ty { | |
2167 | kinds.push("type"); | |
2168 | } | |
2169 | if ct { | |
2170 | kinds.push("const"); | |
dc9dc135 | 2171 | } |
923072b8 FG |
2172 | if inf { |
2173 | kinds.push("generic"); | |
2174 | } | |
2175 | let (kind, s) = match kinds[..] { | |
2176 | [.., _, last] => ( | |
2177 | format!( | |
2178 | "{} and {last}", | |
2179 | kinds[..kinds.len() - 1] | |
2180 | .iter() | |
2181 | .map(|&x| x) | |
2182 | .intersperse(", ") | |
2183 | .collect::<String>() | |
2184 | ), | |
2185 | "s", | |
2186 | ), | |
2187 | [only] => (format!("{only}"), ""), | |
2188 | [] => unreachable!(), | |
2189 | }; | |
2190 | let last_span = *arg_spans.last().unwrap(); | |
2191 | let span: MultiSpan = arg_spans.into(); | |
2192 | let mut err = struct_span_err!( | |
2193 | self.tcx().sess, | |
2194 | span, | |
2195 | E0109, | |
2196 | "{kind} arguments are not allowed on {this_type}", | |
2197 | ); | |
2198 | err.span_label(last_span, format!("{kind} argument{s} not allowed")); | |
2199 | for (what, span) in types_and_spans { | |
2200 | err.span_label(span, format!("not allowed on {what}")); | |
2201 | } | |
2202 | extend(&mut err); | |
2203 | err.emit(); | |
2204 | emitted = true; | |
2205 | } | |
74b04a01 | 2206 | |
923072b8 | 2207 | for segment in segments { |
74b04a01 | 2208 | // Only emit the first error to avoid overloading the user with error messages. |
5869c6ff | 2209 | if let [binding, ..] = segment.args().bindings { |
dc9dc135 | 2210 | Self::prohibit_assoc_ty_binding(self.tcx(), binding.span); |
923072b8 | 2211 | return true; |
dc9dc135 | 2212 | } |
8bb4bdeb | 2213 | } |
923072b8 | 2214 | emitted |
8bb4bdeb XL |
2215 | } |
2216 | ||
48663c56 XL |
2217 | // FIXME(eddyb, varkor) handle type paths here too, not just value ones. |
2218 | pub fn def_ids_for_value_path_segments( | |
2219 | &self, | |
dfeec247 | 2220 | segments: &[hir::PathSegment<'_>], |
48663c56 XL |
2221 | self_ty: Option<Ty<'tcx>>, |
2222 | kind: DefKind, | |
2223 | def_id: DefId, | |
2224 | ) -> Vec<PathSeg> { | |
0731742a XL |
2225 | // We need to extract the type parameters supplied by the user in |
2226 | // the path `path`. Due to the current setup, this is a bit of a | |
2227 | // tricky-process; the problem is that resolve only tells us the | |
2228 | // end-point of the path resolution, and not the intermediate steps. | |
2229 | // Luckily, we can (at least for now) deduce the intermediate steps | |
2230 | // just from the end-point. | |
2231 | // | |
2232 | // There are basically five cases to consider: | |
2233 | // | |
2234 | // 1. Reference to a constructor of a struct: | |
2235 | // | |
2236 | // struct Foo<T>(...) | |
2237 | // | |
2238 | // In this case, the parameters are declared in the type space. | |
2239 | // | |
2240 | // 2. Reference to a constructor of an enum variant: | |
2241 | // | |
2242 | // enum E<T> { Foo(...) } | |
2243 | // | |
2244 | // In this case, the parameters are defined in the type space, | |
2245 | // but may be specified either on the type or the variant. | |
2246 | // | |
2247 | // 3. Reference to a fn item or a free constant: | |
2248 | // | |
2249 | // fn foo<T>() { } | |
2250 | // | |
2251 | // In this case, the path will again always have the form | |
2252 | // `a::b::foo::<T>` where only the final segment should have | |
2253 | // type parameters. However, in this case, those parameters are | |
2254 | // declared on a value, and hence are in the `FnSpace`. | |
2255 | // | |
2256 | // 4. Reference to a method or an associated constant: | |
2257 | // | |
2258 | // impl<A> SomeStruct<A> { | |
2259 | // fn foo<B>(...) | |
2260 | // } | |
2261 | // | |
2262 | // Here we can have a path like | |
2263 | // `a::b::SomeStruct::<A>::foo::<B>`, in which case parameters | |
2264 | // may appear in two places. The penultimate segment, | |
2265 | // `SomeStruct::<A>`, contains parameters in TypeSpace, and the | |
2266 | // final segment, `foo::<B>` contains parameters in fn space. | |
2267 | // | |
0731742a XL |
2268 | // The first step then is to categorize the segments appropriately. |
2269 | ||
2270 | let tcx = self.tcx(); | |
2271 | ||
2272 | assert!(!segments.is_empty()); | |
2273 | let last = segments.len() - 1; | |
2274 | ||
2275 | let mut path_segs = vec![]; | |
2276 | ||
48663c56 | 2277 | match kind { |
0731742a | 2278 | // Case 1. Reference to a struct constructor. |
48663c56 | 2279 | DefKind::Ctor(CtorOf::Struct, ..) => { |
0731742a XL |
2280 | // Everything but the final segment should have no |
2281 | // parameters at all. | |
2282 | let generics = tcx.generics_of(def_id); | |
2283 | // Variant and struct constructors use the | |
2284 | // generics of their parent type definition. | |
2285 | let generics_def_id = generics.parent.unwrap_or(def_id); | |
2286 | path_segs.push(PathSeg(generics_def_id, last)); | |
2287 | } | |
2288 | ||
2289 | // Case 2. Reference to a variant constructor. | |
dfeec247 | 2290 | DefKind::Ctor(CtorOf::Variant, ..) | DefKind::Variant => { |
0731742a XL |
2291 | let adt_def = self_ty.map(|t| t.ty_adt_def().unwrap()); |
2292 | let (generics_def_id, index) = if let Some(adt_def) = adt_def { | |
2293 | debug_assert!(adt_def.is_enum()); | |
5e7ed085 | 2294 | (adt_def.did(), last) |
0731742a XL |
2295 | } else if last >= 1 && segments[last - 1].args.is_some() { |
2296 | // Everything but the penultimate segment should have no | |
2297 | // parameters at all. | |
532ac7d7 XL |
2298 | let mut def_id = def_id; |
2299 | ||
48663c56 XL |
2300 | // `DefKind::Ctor` -> `DefKind::Variant` |
2301 | if let DefKind::Ctor(..) = kind { | |
04454e1e | 2302 | def_id = tcx.parent(def_id); |
532ac7d7 XL |
2303 | } |
2304 | ||
48663c56 | 2305 | // `DefKind::Variant` -> `DefKind::Enum` |
04454e1e | 2306 | let enum_def_id = tcx.parent(def_id); |
0731742a XL |
2307 | (enum_def_id, last - 1) |
2308 | } else { | |
2309 | // FIXME: lint here recommending `Enum::<...>::Variant` form | |
2310 | // instead of `Enum::Variant::<...>` form. | |
2311 | ||
2312 | // Everything but the final segment should have no | |
2313 | // parameters at all. | |
2314 | let generics = tcx.generics_of(def_id); | |
2315 | // Variant and struct constructors use the | |
2316 | // generics of their parent type definition. | |
2317 | (generics.parent.unwrap_or(def_id), last) | |
2318 | }; | |
2319 | path_segs.push(PathSeg(generics_def_id, index)); | |
2320 | } | |
2321 | ||
2322 | // Case 3. Reference to a top-level value. | |
5e7ed085 | 2323 | DefKind::Fn | DefKind::Const | DefKind::ConstParam | DefKind::Static(_) => { |
0731742a XL |
2324 | path_segs.push(PathSeg(def_id, last)); |
2325 | } | |
2326 | ||
2327 | // Case 4. Reference to a method or associated const. | |
ba9703b0 | 2328 | DefKind::AssocFn | DefKind::AssocConst => { |
0731742a XL |
2329 | if segments.len() >= 2 { |
2330 | let generics = tcx.generics_of(def_id); | |
2331 | path_segs.push(PathSeg(generics.parent.unwrap(), last - 1)); | |
2332 | } | |
2333 | path_segs.push(PathSeg(def_id, last)); | |
2334 | } | |
2335 | ||
48663c56 | 2336 | kind => bug!("unexpected definition kind {:?} for {:?}", kind, def_id), |
0731742a XL |
2337 | } |
2338 | ||
2339 | debug!("path_segs = {:?}", path_segs); | |
2340 | ||
2341 | path_segs | |
2342 | } | |
2343 | ||
a1dfa0c6 | 2344 | // Check a type `Path` and convert it to a `Ty`. |
dfeec247 XL |
2345 | pub fn res_to_ty( |
2346 | &self, | |
2347 | opt_self_ty: Option<Ty<'tcx>>, | |
2348 | path: &hir::Path<'_>, | |
2349 | permit_variants: bool, | |
2350 | ) -> Ty<'tcx> { | |
a7813a04 XL |
2351 | let tcx = self.tcx(); |
2352 | ||
dfeec247 XL |
2353 | debug!( |
2354 | "res_to_ty(res={:?}, opt_self_ty={:?}, path_segments={:?})", | |
2355 | path.res, opt_self_ty, path.segments | |
2356 | ); | |
a7813a04 | 2357 | |
476ff2be | 2358 | let span = path.span; |
48663c56 | 2359 | match path.res { |
416331ca | 2360 | Res::Def(DefKind::OpaqueTy, did) => { |
dc9dc135 | 2361 | // Check for desugared `impl Trait`. |
0bf4aa26 | 2362 | assert!(ty::is_impl_trait_defn(tcx, did).is_none()); |
8faf50e0 | 2363 | let item_segment = path.segments.split_last().unwrap(); |
923072b8 FG |
2364 | self.prohibit_generics(item_segment.1.iter(), |err| { |
2365 | err.note("`impl Trait` types can't have type parameters"); | |
2366 | }); | |
8faf50e0 | 2367 | let substs = self.ast_path_substs_for_ty(span, did, item_segment.0); |
dfeec247 | 2368 | self.normalize_ty(span, tcx.mk_opaque(did, substs)) |
8faf50e0 | 2369 | } |
ba9703b0 XL |
2370 | Res::Def( |
2371 | DefKind::Enum | |
2372 | | DefKind::TyAlias | |
2373 | | DefKind::Struct | |
2374 | | DefKind::Union | |
2375 | | DefKind::ForeignTy, | |
2376 | did, | |
2377 | ) => { | |
476ff2be | 2378 | assert_eq!(opt_self_ty, None); |
923072b8 | 2379 | self.prohibit_generics(path.segments.split_last().unwrap().1.iter(), |_| {}); |
32a655c1 | 2380 | self.ast_path_to_ty(span, did, path.segments.last().unwrap()) |
a7813a04 | 2381 | } |
48663c56 | 2382 | Res::Def(kind @ DefKind::Variant, def_id) if permit_variants => { |
c30ab7b3 SL |
2383 | // Convert "variant type" as if it were a real type. |
2384 | // The resulting `Ty` is type of the variant's enum for now. | |
476ff2be | 2385 | assert_eq!(opt_self_ty, None); |
0731742a | 2386 | |
48663c56 | 2387 | let path_segs = |
c295e0f8 | 2388 | self.def_ids_for_value_path_segments(path.segments, None, kind, def_id); |
0731742a XL |
2389 | let generic_segs: FxHashSet<_> = |
2390 | path_segs.iter().map(|PathSeg(_, index)| index).collect(); | |
923072b8 FG |
2391 | self.prohibit_generics( |
2392 | path.segments.iter().enumerate().filter_map(|(index, seg)| { | |
dfeec247 | 2393 | if !generic_segs.contains(&index) { Some(seg) } else { None } |
923072b8 FG |
2394 | }), |
2395 | |err| { | |
2396 | err.note("enum variants can't have type parameters"); | |
dfeec247 | 2397 | }, |
923072b8 | 2398 | ); |
0731742a XL |
2399 | |
2400 | let PathSeg(def_id, index) = path_segs.last().unwrap(); | |
2401 | self.ast_path_to_ty(span, *def_id, &path.segments[*index]) | |
c30ab7b3 | 2402 | } |
dc9dc135 | 2403 | Res::Def(DefKind::TyParam, def_id) => { |
476ff2be | 2404 | assert_eq!(opt_self_ty, None); |
923072b8 FG |
2405 | self.prohibit_generics(path.segments.iter(), |err| { |
2406 | if let Some(span) = tcx.def_ident_span(def_id) { | |
2407 | let name = tcx.item_name(def_id); | |
2408 | err.span_note(span, &format!("type parameter `{name}` defined here")); | |
2409 | } | |
2410 | }); | |
9e0c209e | 2411 | |
04454e1e FG |
2412 | let def_id = def_id.expect_local(); |
2413 | let item_def_id = tcx.hir().ty_param_owner(def_id); | |
7cac9316 | 2414 | let generics = tcx.generics_of(item_def_id); |
04454e1e FG |
2415 | let index = generics.param_def_id_to_index[&def_id.to_def_id()]; |
2416 | tcx.mk_ty_param(index, tcx.hir().ty_param_name(def_id)) | |
a7813a04 | 2417 | } |
5099ac24 | 2418 | Res::SelfTy { trait_: Some(_), alias_to: None } => { |
dc9dc135 | 2419 | // `Self` in trait or type alias. |
476ff2be | 2420 | assert_eq!(opt_self_ty, None); |
923072b8 FG |
2421 | self.prohibit_generics(path.segments.iter(), |err| { |
2422 | if let [hir::PathSegment { args: Some(args), ident, .. }] = &path.segments[..] { | |
2423 | err.span_suggestion_verbose( | |
2424 | ident.span.shrink_to_hi().to(args.span_ext), | |
2425 | "the `Self` type doesn't accept type parameters", | |
2426 | "", | |
2427 | Applicability::MaybeIncorrect, | |
2428 | ); | |
2429 | } | |
2430 | }); | |
e1599b0c | 2431 | tcx.types.self_param |
9346a6ac | 2432 | } |
5099ac24 | 2433 | Res::SelfTy { trait_: _, alias_to: Some((def_id, forbid_generic)) } => { |
dc9dc135 | 2434 | // `Self` in impl (we know the concrete type). |
476ff2be | 2435 | assert_eq!(opt_self_ty, None); |
dc9dc135 | 2436 | // Try to evaluate any array length constants. |
5099ac24 | 2437 | let ty = tcx.at(span).type_of(def_id); |
923072b8 FG |
2438 | let span_of_impl = tcx.span_of_impl(def_id); |
2439 | self.prohibit_generics(path.segments.iter(), |err| { | |
2440 | let def_id = match *ty.kind() { | |
2441 | ty::Adt(self_def, _) => self_def.did(), | |
2442 | _ => return, | |
2443 | }; | |
2444 | ||
2445 | let type_name = tcx.item_name(def_id); | |
2446 | let span_of_ty = tcx.def_ident_span(def_id); | |
2447 | let generics = tcx.generics_of(def_id).count(); | |
2448 | ||
2449 | let msg = format!("`Self` is of type `{ty}`"); | |
2450 | if let (Ok(i_sp), Some(t_sp)) = (span_of_impl, span_of_ty) { | |
2451 | let i_sp = tcx.sess.source_map().guess_head_span(i_sp); | |
2452 | let mut span: MultiSpan = vec![t_sp].into(); | |
2453 | span.push_span_label( | |
2454 | i_sp, | |
2455 | &format!("`Self` is on type `{type_name}` in this `impl`"), | |
2456 | ); | |
2457 | let mut postfix = ""; | |
2458 | if generics == 0 { | |
2459 | postfix = ", which doesn't have generic parameters"; | |
2460 | } | |
2461 | span.push_span_label( | |
2462 | t_sp, | |
2463 | &format!("`Self` corresponds to this type{postfix}"), | |
2464 | ); | |
2465 | err.span_note(span, &msg); | |
2466 | } else { | |
2467 | err.note(&msg); | |
2468 | } | |
2469 | for segment in path.segments { | |
2470 | if let Some(args) = segment.args && segment.ident.name == kw::SelfUpper { | |
2471 | if generics == 0 { | |
2472 | // FIXME(estebank): we could also verify that the arguments being | |
2473 | // work for the `enum`, instead of just looking if it takes *any*. | |
2474 | err.span_suggestion_verbose( | |
2475 | segment.ident.span.shrink_to_hi().to(args.span_ext), | |
2476 | "the `Self` type doesn't accept type parameters", | |
2477 | "", | |
2478 | Applicability::MachineApplicable, | |
2479 | ); | |
2480 | return; | |
2481 | } else { | |
2482 | err.span_suggestion_verbose( | |
2483 | segment.ident.span, | |
2484 | format!( | |
2485 | "the `Self` type doesn't accept type parameters, use the \ | |
2486 | concrete type's name `{type_name}` instead if you want to \ | |
2487 | specify its type parameters" | |
2488 | ), | |
2489 | type_name.to_string(), | |
2490 | Applicability::MaybeIncorrect, | |
2491 | ); | |
2492 | } | |
2493 | } | |
2494 | } | |
2495 | }); | |
5099ac24 FG |
2496 | // HACK(min_const_generics): Forbid generic `Self` types |
2497 | // here as we can't easily do that during nameres. | |
2498 | // | |
2499 | // We do this before normalization as we otherwise allow | |
2500 | // ```rust | |
2501 | // trait AlwaysApplicable { type Assoc; } | |
2502 | // impl<T: ?Sized> AlwaysApplicable for T { type Assoc = usize; } | |
2503 | // | |
2504 | // trait BindsParam<T> { | |
2505 | // type ArrayTy; | |
2506 | // } | |
2507 | // impl<T> BindsParam<T> for <T as AlwaysApplicable>::Assoc { | |
2508 | // type ArrayTy = [u8; Self::MAX]; | |
2509 | // } | |
2510 | // ``` | |
2511 | // Note that the normalization happens in the param env of | |
2512 | // the anon const, which is empty. This is why the | |
2513 | // `AlwaysApplicable` impl needs a `T: ?Sized` bound for | |
2514 | // this to compile if we were to normalize here. | |
2515 | if forbid_generic && ty.needs_subst() { | |
1b1a35ee XL |
2516 | let mut err = tcx.sess.struct_span_err( |
2517 | path.span, | |
2518 | "generic `Self` types are currently not permitted in anonymous constants", | |
2519 | ); | |
2520 | if let Some(hir::Node::Item(&hir::Item { | |
5869c6ff | 2521 | kind: hir::ItemKind::Impl(ref impl_), |
1b1a35ee XL |
2522 | .. |
2523 | })) = tcx.hir().get_if_local(def_id) | |
2524 | { | |
5869c6ff | 2525 | err.span_note(impl_.self_ty.span, "not a concrete type"); |
1b1a35ee XL |
2526 | } |
2527 | err.emit(); | |
2528 | tcx.ty_error() | |
2529 | } else { | |
5099ac24 | 2530 | self.normalize_ty(span, ty) |
1b1a35ee | 2531 | } |
a7813a04 | 2532 | } |
dc9dc135 | 2533 | Res::Def(DefKind::AssocTy, def_id) => { |
0731742a | 2534 | debug_assert!(path.segments.len() >= 2); |
923072b8 | 2535 | self.prohibit_generics(path.segments[..path.segments.len() - 2].iter(), |_| {}); |
dfeec247 XL |
2536 | self.qpath_to_ty( |
2537 | span, | |
2538 | opt_self_ty, | |
2539 | def_id, | |
2540 | &path.segments[path.segments.len() - 2], | |
2541 | path.segments.last().unwrap(), | |
2542 | ) | |
a7813a04 | 2543 | } |
48663c56 | 2544 | Res::PrimTy(prim_ty) => { |
476ff2be | 2545 | assert_eq!(opt_self_ty, None); |
923072b8 FG |
2546 | self.prohibit_generics(path.segments.iter(), |err| { |
2547 | let name = prim_ty.name_str(); | |
2548 | for segment in path.segments { | |
2549 | if let Some(args) = segment.args { | |
2550 | err.span_suggestion_verbose( | |
2551 | segment.ident.span.shrink_to_hi().to(args.span_ext), | |
2552 | &format!("primitive type `{name}` doesn't have generic parameters"), | |
2553 | "", | |
2554 | Applicability::MaybeIncorrect, | |
2555 | ); | |
2556 | } | |
2557 | } | |
2558 | }); | |
8bb4bdeb | 2559 | match prim_ty { |
dfeec247 XL |
2560 | hir::PrimTy::Bool => tcx.types.bool, |
2561 | hir::PrimTy::Char => tcx.types.char, | |
5869c6ff XL |
2562 | hir::PrimTy::Int(it) => tcx.mk_mach_int(ty::int_ty(it)), |
2563 | hir::PrimTy::Uint(uit) => tcx.mk_mach_uint(ty::uint_ty(uit)), | |
2564 | hir::PrimTy::Float(ft) => tcx.mk_mach_float(ty::float_ty(ft)), | |
f035d41b | 2565 | hir::PrimTy::Str => tcx.types.str_, |
8bb4bdeb | 2566 | } |
a7813a04 | 2567 | } |
48663c56 | 2568 | Res::Err => { |
a7813a04 | 2569 | self.set_tainted_by_errors(); |
f035d41b | 2570 | self.tcx().ty_error() |
a7813a04 | 2571 | } |
dfeec247 | 2572 | _ => span_bug!(span, "unexpected resolution: {:?}", path.res), |
c34b1796 | 2573 | } |
9346a6ac | 2574 | } |
c34b1796 | 2575 | |
a7813a04 XL |
2576 | /// Parses the programmer's textual representation of a type into our |
2577 | /// internal notion of a type. | |
dfeec247 | 2578 | pub fn ast_ty_to_ty(&self, ast_ty: &hir::Ty<'_>) -> Ty<'tcx> { |
a2a8927a XL |
2579 | self.ast_ty_to_ty_inner(ast_ty, false, false) |
2580 | } | |
2581 | ||
2582 | /// Parses the programmer's textual representation of a type into our | |
2583 | /// internal notion of a type. This is meant to be used within a path. | |
2584 | pub fn ast_ty_to_ty_in_path(&self, ast_ty: &hir::Ty<'_>) -> Ty<'tcx> { | |
2585 | self.ast_ty_to_ty_inner(ast_ty, false, true) | |
3dfed10e XL |
2586 | } |
2587 | ||
2588 | /// Turns a `hir::Ty` into a `Ty`. For diagnostics' purposes we keep track of whether trait | |
2589 | /// objects are borrowed like `&dyn Trait` to avoid emitting redundant errors. | |
cdc7bbd5 | 2590 | #[tracing::instrument(level = "debug", skip(self))] |
a2a8927a | 2591 | fn ast_ty_to_ty_inner(&self, ast_ty: &hir::Ty<'_>, borrowed: bool, in_path: bool) -> Ty<'tcx> { |
a7813a04 | 2592 | let tcx = self.tcx(); |
1a4d82fc | 2593 | |
e74abb32 | 2594 | let result_ty = match ast_ty.kind { |
c295e0f8 | 2595 | hir::TyKind::Slice(ref ty) => tcx.mk_slice(self.ast_ty_to_ty(ty)), |
8faf50e0 | 2596 | hir::TyKind::Ptr(ref mt) => { |
c295e0f8 | 2597 | tcx.mk_ptr(ty::TypeAndMut { ty: self.ast_ty_to_ty(mt.ty), mutbl: mt.mutbl }) |
a7813a04 | 2598 | } |
8faf50e0 | 2599 | hir::TyKind::Rptr(ref region, ref mt) => { |
32a655c1 | 2600 | let r = self.ast_region_to_region(region, None); |
cdc7bbd5 | 2601 | debug!(?r); |
a2a8927a | 2602 | let t = self.ast_ty_to_ty_inner(mt.ty, true, false); |
dfeec247 | 2603 | tcx.mk_ref(r, ty::TypeAndMut { ty: t, mutbl: mt.mutbl }) |
a7813a04 | 2604 | } |
dfeec247 | 2605 | hir::TyKind::Never => tcx.types.never, |
c295e0f8 XL |
2606 | hir::TyKind::Tup(fields) => tcx.mk_tup(fields.iter().map(|t| self.ast_ty_to_ty(t))), |
2607 | hir::TyKind::BareFn(bf) => { | |
2608 | require_c_abi_if_c_variadic(tcx, bf.decl, bf.abi, ast_ty.span); | |
6a06907d | 2609 | |
74b04a01 | 2610 | tcx.mk_fn_ptr(self.ty_of_fn( |
cdc7bbd5 | 2611 | ast_ty.hir_id, |
74b04a01 XL |
2612 | bf.unsafety, |
2613 | bf.abi, | |
c295e0f8 | 2614 | bf.decl, |
74b04a01 | 2615 | None, |
6a06907d | 2616 | Some(ast_ty), |
74b04a01 | 2617 | )) |
1a4d82fc | 2618 | } |
c295e0f8 | 2619 | hir::TyKind::TraitObject(bounds, ref lifetime, _) => { |
a2a8927a | 2620 | self.maybe_lint_bare_trait(ast_ty, in_path); |
3dfed10e | 2621 | self.conv_object_ty_poly_trait_ref(ast_ty.span, bounds, lifetime, borrowed) |
a7813a04 | 2622 | } |
8faf50e0 | 2623 | hir::TyKind::Path(hir::QPath::Resolved(ref maybe_qself, ref path)) => { |
cdc7bbd5 | 2624 | debug!(?maybe_qself, ?path); |
dfeec247 | 2625 | let opt_self_ty = maybe_qself.as_ref().map(|qself| self.ast_ty_to_ty(qself)); |
48663c56 | 2626 | self.res_to_ty(opt_self_ty, path, false) |
476ff2be | 2627 | } |
c295e0f8 | 2628 | hir::TyKind::OpaqueDef(item_id, lifetimes) => { |
6a06907d XL |
2629 | let opaque_ty = tcx.hir().item(item_id); |
2630 | let def_id = item_id.def_id.to_def_id(); | |
f035d41b XL |
2631 | |
2632 | match opaque_ty.kind { | |
923072b8 FG |
2633 | hir::ItemKind::OpaqueTy(hir::OpaqueTy { origin, .. }) => { |
2634 | self.impl_trait_ty_to_ty(def_id, lifetimes, origin) | |
2635 | } | |
f035d41b XL |
2636 | ref i => bug!("`impl Trait` pointed to non-opaque type?? {:#?}", i), |
2637 | } | |
dc9dc135 | 2638 | } |
8faf50e0 | 2639 | hir::TyKind::Path(hir::QPath::TypeRelative(ref qself, ref segment)) => { |
cdc7bbd5 | 2640 | debug!(?qself, ?segment); |
a2a8927a | 2641 | let ty = self.ast_ty_to_ty_inner(qself, false, true); |
923072b8 | 2642 | self.associated_path_to_ty(ast_ty.hir_id, ast_ty.span, ty, qself, segment, false) |
dfeec247 | 2643 | .map(|(ty, _, _)| ty) |
f035d41b | 2644 | .unwrap_or_else(|_| tcx.ty_error()) |
a7813a04 | 2645 | } |
a2a8927a | 2646 | hir::TyKind::Path(hir::QPath::LangItem(lang_item, span, _)) => { |
3dfed10e | 2647 | let def_id = tcx.require_lang_item(lang_item, Some(span)); |
cdc7bbd5 | 2648 | let (substs, _) = self.create_substs_for_ast_path( |
3dfed10e XL |
2649 | span, |
2650 | def_id, | |
2651 | &[], | |
5869c6ff | 2652 | &hir::PathSegment::invalid(), |
3dfed10e XL |
2653 | &GenericArgs::none(), |
2654 | true, | |
2655 | None, | |
2656 | ); | |
04454e1e FG |
2657 | EarlyBinder(self.normalize_ty(span, tcx.at(span).type_of(def_id))) |
2658 | .subst(tcx, substs) | |
3dfed10e | 2659 | } |
8faf50e0 | 2660 | hir::TyKind::Array(ref ty, ref length) => { |
a2a8927a XL |
2661 | let length = match length { |
2662 | &hir::ArrayLen::Infer(_, span) => self.ct_infer(tcx.types.usize, None, span), | |
2663 | hir::ArrayLen::Body(constant) => { | |
2664 | let length_def_id = tcx.hir().local_def_id(constant.hir_id); | |
2665 | ty::Const::from_anon_const(tcx, length_def_id) | |
2666 | } | |
2667 | }; | |
2668 | ||
c295e0f8 | 2669 | let array_ty = tcx.mk_ty(ty::Array(self.ast_ty_to_ty(ty), length)); |
ea8adc8c | 2670 | self.normalize_ty(ast_ty.span, array_ty) |
1a4d82fc | 2671 | } |
cdc7bbd5 | 2672 | hir::TyKind::Typeof(ref e) => { |
04454e1e FG |
2673 | let ty = tcx.type_of(tcx.hir().local_def_id(e.hir_id)); |
2674 | let span = ast_ty.span; | |
2675 | tcx.sess.emit_err(TypeofReservedKeywordUsed { | |
2676 | span, | |
2677 | ty, | |
2678 | opt_sugg: Some((span, Applicability::MachineApplicable)) | |
2679 | .filter(|_| ty.is_suggestable(tcx)), | |
2680 | }); | |
2681 | ||
2682 | ty | |
a7813a04 | 2683 | } |
8faf50e0 | 2684 | hir::TyKind::Infer => { |
b7449926 | 2685 | // Infer also appears as the type of arguments or return |
94222f64 | 2686 | // values in an ExprKind::Closure, or as |
a7813a04 XL |
2687 | // the type of local variables. Both of these cases are |
2688 | // handled specially and will not descend into this routine. | |
dc9dc135 | 2689 | self.ty_infer(None, ast_ty.span) |
cc61c64b | 2690 | } |
f035d41b | 2691 | hir::TyKind::Err => tcx.ty_error(), |
a7813a04 | 2692 | }; |
1a4d82fc | 2693 | |
cdc7bbd5 | 2694 | debug!(?result_ty); |
dc9dc135 | 2695 | |
ea8adc8c | 2696 | self.record_ty(ast_ty.hir_id, result_ty, ast_ty.span); |
a7813a04 | 2697 | result_ty |
1a4d82fc | 2698 | } |
1a4d82fc | 2699 | |
cdc7bbd5 | 2700 | fn impl_trait_ty_to_ty( |
94b46f34 XL |
2701 | &self, |
2702 | def_id: DefId, | |
dfeec247 | 2703 | lifetimes: &[hir::GenericArg<'_>], |
923072b8 | 2704 | origin: OpaqueTyOrigin, |
94b46f34 | 2705 | ) -> Ty<'tcx> { |
ff7c6d11 XL |
2706 | debug!("impl_trait_ty_to_ty(def_id={:?}, lifetimes={:?})", def_id, lifetimes); |
2707 | let tcx = self.tcx(); | |
94b46f34 | 2708 | |
ff7c6d11 XL |
2709 | let generics = tcx.generics_of(def_id); |
2710 | ||
ff7c6d11 | 2711 | debug!("impl_trait_ty_to_ty: generics={:?}", generics); |
532ac7d7 | 2712 | let substs = InternalSubsts::for_item(tcx, def_id, |param, _| { |
94b46f34 XL |
2713 | if let Some(i) = (param.index as usize).checked_sub(generics.parent_count) { |
2714 | // Our own parameters are the resolved lifetimes. | |
c295e0f8 XL |
2715 | if let GenericParamDefKind::Lifetime = param.kind { |
2716 | if let hir::GenericArg::Lifetime(lifetime) = &lifetimes[i] { | |
94222f64 | 2717 | self.ast_region_to_region(lifetime, None).into() |
c295e0f8 XL |
2718 | } else { |
2719 | bug!() | |
94b46f34 | 2720 | } |
c295e0f8 XL |
2721 | } else { |
2722 | bug!() | |
94b46f34 XL |
2723 | } |
2724 | } else { | |
94b46f34 | 2725 | match param.kind { |
f035d41b XL |
2726 | // For RPIT (return position impl trait), only lifetimes |
2727 | // mentioned in the impl Trait predicate are captured by | |
2728 | // the opaque type, so the lifetime parameters from the | |
2729 | // parent item need to be replaced with `'static`. | |
2730 | // | |
2731 | // For `impl Trait` in the types of statics, constants, | |
2732 | // locals and type aliases. These capture all parent | |
2733 | // lifetimes, so they can use their identity subst. | |
923072b8 FG |
2734 | GenericParamDefKind::Lifetime |
2735 | if matches!( | |
2736 | origin, | |
2737 | hir::OpaqueTyOrigin::FnReturn(..) | hir::OpaqueTyOrigin::AsyncFn(..) | |
2738 | ) => | |
2739 | { | |
f035d41b XL |
2740 | tcx.lifetimes.re_static.into() |
2741 | } | |
dfeec247 | 2742 | _ => tcx.mk_param_from_def(param), |
ff7c6d11 XL |
2743 | } |
2744 | } | |
94b46f34 | 2745 | }); |
dc9dc135 | 2746 | debug!("impl_trait_ty_to_ty: substs={:?}", substs); |
ff7c6d11 | 2747 | |
b7449926 | 2748 | let ty = tcx.mk_opaque(def_id, substs); |
94b46f34 XL |
2749 | debug!("impl_trait_ty_to_ty: {}", ty); |
2750 | ty | |
ff7c6d11 XL |
2751 | } |
2752 | ||
dfeec247 | 2753 | pub fn ty_of_arg(&self, ty: &hir::Ty<'_>, expected_ty: Option<Ty<'tcx>>) -> Ty<'tcx> { |
e74abb32 | 2754 | match ty.kind { |
8faf50e0 | 2755 | hir::TyKind::Infer if expected_ty.is_some() => { |
ea8adc8c XL |
2756 | self.record_ty(ty.hir_id, expected_ty.unwrap(), ty.span); |
2757 | expected_ty.unwrap() | |
2758 | } | |
32a655c1 | 2759 | _ => self.ast_ty_to_ty(ty), |
a7813a04 XL |
2760 | } |
2761 | } | |
1a4d82fc | 2762 | |
dfeec247 XL |
2763 | pub fn ty_of_fn( |
2764 | &self, | |
cdc7bbd5 | 2765 | hir_id: hir::HirId, |
dfeec247 XL |
2766 | unsafety: hir::Unsafety, |
2767 | abi: abi::Abi, | |
2768 | decl: &hir::FnDecl<'_>, | |
04454e1e | 2769 | generics: Option<&hir::Generics<'_>>, |
6a06907d | 2770 | hir_ty: Option<&hir::Ty<'_>>, |
dfeec247 | 2771 | ) -> ty::PolyFnSig<'tcx> { |
32a655c1 | 2772 | debug!("ty_of_fn"); |
1a4d82fc | 2773 | |
ea8adc8c | 2774 | let tcx = self.tcx(); |
cdc7bbd5 XL |
2775 | let bound_vars = tcx.late_bound_vars(hir_id); |
2776 | debug!(?bound_vars); | |
1a4d82fc | 2777 | |
74b04a01 | 2778 | // We proactively collect all the inferred type params to emit a single error per fn def. |
5099ac24 | 2779 | let mut visitor = HirPlaceholderCollector::default(); |
04454e1e FG |
2780 | let mut infer_replacements = vec![]; |
2781 | ||
2782 | if let Some(generics) = generics { | |
2783 | walk_generics(&mut visitor, generics); | |
dfeec247 | 2784 | } |
74b04a01 | 2785 | |
04454e1e FG |
2786 | let input_tys: Vec<_> = decl |
2787 | .inputs | |
2788 | .iter() | |
2789 | .enumerate() | |
2790 | .map(|(i, a)| { | |
2791 | if let hir::TyKind::Infer = a.kind && !self.allow_ty_infer() { | |
2792 | if let Some(suggested_ty) = | |
2793 | self.suggest_trait_fn_ty_for_impl_fn_infer(hir_id, Some(i)) | |
2794 | { | |
2795 | infer_replacements.push((a.span, suggested_ty.to_string())); | |
2796 | return suggested_ty; | |
2797 | } | |
2798 | } | |
2799 | ||
2800 | // Only visit the type looking for `_` if we didn't fix the type above | |
2801 | visitor.visit_ty(a); | |
2802 | self.ty_of_arg(a, None) | |
2803 | }) | |
2804 | .collect(); | |
2805 | ||
a7813a04 | 2806 | let output_ty = match decl.output { |
c295e0f8 | 2807 | hir::FnRetTy::Return(output) => { |
04454e1e FG |
2808 | if let hir::TyKind::Infer = output.kind |
2809 | && !self.allow_ty_infer() | |
2810 | && let Some(suggested_ty) = | |
2811 | self.suggest_trait_fn_ty_for_impl_fn_infer(hir_id, None) | |
2812 | { | |
2813 | infer_replacements.push((output.span, suggested_ty.to_string())); | |
2814 | suggested_ty | |
2815 | } else { | |
2816 | visitor.visit_ty(output); | |
2817 | self.ast_ty_to_ty(output) | |
2818 | } | |
dfeec247 | 2819 | } |
74b04a01 | 2820 | hir::FnRetTy::DefaultReturn(..) => tcx.mk_unit(), |
a7813a04 | 2821 | }; |
1a4d82fc | 2822 | |
32a655c1 | 2823 | debug!("ty_of_fn: output_ty={:?}", output_ty); |
9e0c209e | 2824 | |
04454e1e | 2825 | let fn_ty = tcx.mk_fn_sig(input_tys.into_iter(), output_ty, decl.c_variadic, unsafety, abi); |
cdc7bbd5 | 2826 | let bare_fn_ty = ty::Binder::bind_with_vars(fn_ty, bound_vars); |
dfeec247 | 2827 | |
04454e1e | 2828 | if !self.allow_ty_infer() && !(visitor.0.is_empty() && infer_replacements.is_empty()) { |
dfeec247 XL |
2829 | // We always collect the spans for placeholder types when evaluating `fn`s, but we |
2830 | // only want to emit an error complaining about them if infer types (`_`) are not | |
ba9703b0 XL |
2831 | // allowed. `allow_ty_infer` gates this behavior. We check for the presence of |
2832 | // `ident_span` to not emit an error twice when we have `fn foo(_: fn() -> _)`. | |
6a06907d | 2833 | |
04454e1e | 2834 | let mut diag = crate::collect::placeholder_type_error_diag( |
dfeec247 | 2835 | tcx, |
04454e1e | 2836 | generics, |
dfeec247 | 2837 | visitor.0, |
04454e1e | 2838 | infer_replacements.iter().map(|(s, _)| *s).collect(), |
ba9703b0 | 2839 | true, |
6a06907d | 2840 | hir_ty, |
136023e0 | 2841 | "function", |
dfeec247 | 2842 | ); |
04454e1e FG |
2843 | |
2844 | if !infer_replacements.is_empty() { | |
2845 | diag.multipart_suggestion(&format!( | |
2846 | "try replacing `_` with the type{} in the corresponding trait method signature", | |
2847 | rustc_errors::pluralize!(infer_replacements.len()), | |
2848 | ), infer_replacements, Applicability::MachineApplicable); | |
2849 | } | |
2850 | ||
2851 | diag.emit(); | |
dfeec247 | 2852 | } |
ea8adc8c XL |
2853 | |
2854 | // Find any late-bound regions declared in return type that do | |
0bf4aa26 | 2855 | // not appear in the arguments. These are not well-formed. |
ea8adc8c XL |
2856 | // |
2857 | // Example: | |
2858 | // for<'a> fn() -> &'a str <-- 'a is bad | |
2859 | // for<'a> fn(&'a String) -> &'a str <-- 'a is ok | |
2860 | let inputs = bare_fn_ty.inputs(); | |
dfeec247 XL |
2861 | let late_bound_in_args = |
2862 | tcx.collect_constrained_late_bound_regions(&inputs.map_bound(|i| i.to_owned())); | |
ea8adc8c XL |
2863 | let output = bare_fn_ty.output(); |
2864 | let late_bound_in_ret = tcx.collect_referenced_late_bound_regions(&output); | |
3dfed10e XL |
2865 | |
2866 | self.validate_late_bound_regions(late_bound_in_args, late_bound_in_ret, |br_name| { | |
2867 | struct_span_err!( | |
dfeec247 XL |
2868 | tcx.sess, |
2869 | decl.output.span(), | |
2870 | E0581, | |
3dfed10e XL |
2871 | "return type references {}, which is not constrained by the fn input types", |
2872 | br_name | |
2873 | ) | |
2874 | }); | |
2875 | ||
2876 | bare_fn_ty | |
2877 | } | |
2878 | ||
04454e1e FG |
2879 | /// Given a fn_hir_id for a impl function, suggest the type that is found on the |
2880 | /// corresponding function in the trait that the impl implements, if it exists. | |
2881 | /// If arg_idx is Some, then it corresponds to an input type index, otherwise it | |
2882 | /// corresponds to the return type. | |
2883 | fn suggest_trait_fn_ty_for_impl_fn_infer( | |
2884 | &self, | |
2885 | fn_hir_id: hir::HirId, | |
2886 | arg_idx: Option<usize>, | |
2887 | ) -> Option<Ty<'tcx>> { | |
2888 | let tcx = self.tcx(); | |
2889 | let hir = tcx.hir(); | |
2890 | ||
2891 | let hir::Node::ImplItem(hir::ImplItem { kind: hir::ImplItemKind::Fn(..), ident, .. }) = | |
2892 | hir.get(fn_hir_id) else { return None }; | |
2893 | let hir::Node::Item(hir::Item { kind: hir::ItemKind::Impl(i), .. }) = | |
2894 | hir.get(hir.get_parent_node(fn_hir_id)) else { bug!("ImplItem should have Impl parent") }; | |
2895 | ||
2896 | let trait_ref = | |
2897 | self.instantiate_mono_trait_ref(i.of_trait.as_ref()?, self.ast_ty_to_ty(i.self_ty)); | |
2898 | ||
2899 | let assoc = tcx.associated_items(trait_ref.def_id).find_by_name_and_kind( | |
2900 | tcx, | |
2901 | *ident, | |
2902 | ty::AssocKind::Fn, | |
2903 | trait_ref.def_id, | |
2904 | )?; | |
2905 | ||
2906 | let fn_sig = tcx.bound_fn_sig(assoc.def_id).subst( | |
2907 | tcx, | |
2908 | trait_ref.substs.extend_to(tcx, assoc.def_id, |param, _| tcx.mk_param_from_def(param)), | |
2909 | ); | |
2910 | ||
2911 | let ty = if let Some(arg_idx) = arg_idx { fn_sig.input(arg_idx) } else { fn_sig.output() }; | |
2912 | ||
2913 | Some(tcx.liberate_late_bound_regions(fn_hir_id.expect_owner().to_def_id(), ty)) | |
2914 | } | |
2915 | ||
3dfed10e XL |
2916 | fn validate_late_bound_regions( |
2917 | &self, | |
fc512014 XL |
2918 | constrained_regions: FxHashSet<ty::BoundRegionKind>, |
2919 | referenced_regions: FxHashSet<ty::BoundRegionKind>, | |
5e7ed085 | 2920 | generate_err: impl Fn(&str) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>, |
3dfed10e XL |
2921 | ) { |
2922 | for br in referenced_regions.difference(&constrained_regions) { | |
2923 | let br_name = match *br { | |
923072b8 FG |
2924 | ty::BrNamed(_, kw::UnderscoreLifetime) | ty::BrAnon(_) | ty::BrEnv => { |
2925 | "an anonymous lifetime".to_string() | |
2926 | } | |
3dfed10e | 2927 | ty::BrNamed(_, name) => format!("lifetime `{}`", name), |
3dfed10e XL |
2928 | }; |
2929 | ||
2930 | let mut err = generate_err(&br_name); | |
2931 | ||
923072b8 | 2932 | if let ty::BrNamed(_, kw::UnderscoreLifetime) | ty::BrAnon(_) = *br { |
2c00a5a8 XL |
2933 | // The only way for an anonymous lifetime to wind up |
2934 | // in the return type but **also** be unconstrained is | |
2935 | // if it only appears in "associated types" in the | |
3dfed10e | 2936 | // input. See #47511 and #62200 for examples. In this case, |
2c00a5a8 XL |
2937 | // though we can easily give a hint that ought to be |
2938 | // relevant. | |
dfeec247 | 2939 | err.note( |
74b04a01 | 2940 | "lifetimes appearing in an associated type are not considered constrained", |
dfeec247 | 2941 | ); |
2c00a5a8 | 2942 | } |
3dfed10e | 2943 | |
2c00a5a8 | 2944 | err.emit(); |
ea8adc8c | 2945 | } |
a7813a04 | 2946 | } |
1a4d82fc | 2947 | |
a7813a04 XL |
2948 | /// Given the bounds on an object, determines what single region bound (if any) we can |
2949 | /// use to summarize this type. The basic idea is that we will use the bound the user | |
2950 | /// provided, if they provided one, and otherwise search the supertypes of trait bounds | |
2951 | /// for region bounds. It may be that we can derive no bound at all, in which case | |
2952 | /// we return `None`. | |
dfeec247 XL |
2953 | fn compute_object_lifetime_bound( |
2954 | &self, | |
a7813a04 | 2955 | span: Span, |
cdc7bbd5 | 2956 | existential_predicates: &'tcx ty::List<ty::Binder<'tcx, ty::ExistentialPredicate<'tcx>>>, |
dfeec247 | 2957 | ) -> Option<ty::Region<'tcx>> // if None, use the default |
a7813a04 XL |
2958 | { |
2959 | let tcx = self.tcx(); | |
85aaf69f | 2960 | |
dfeec247 | 2961 | debug!("compute_opt_region_bound(existential_predicates={:?})", existential_predicates); |
1a4d82fc | 2962 | |
a7813a04 XL |
2963 | // No explicit region bound specified. Therefore, examine trait |
2964 | // bounds and see if we can derive region bounds from those. | |
dfeec247 | 2965 | let derived_region_bounds = object_region_bounds(tcx, existential_predicates); |
1a4d82fc | 2966 | |
a7813a04 XL |
2967 | // If there are no derived region bounds, then report back that we |
2968 | // can find no region bound. The caller will use the default. | |
2969 | if derived_region_bounds.is_empty() { | |
2970 | return None; | |
2971 | } | |
1a4d82fc | 2972 | |
a7813a04 XL |
2973 | // If any of the derived region bounds are 'static, that is always |
2974 | // the best choice. | |
5099ac24 | 2975 | if derived_region_bounds.iter().any(|r| r.is_static()) { |
48663c56 | 2976 | return Some(tcx.lifetimes.re_static); |
a7813a04 | 2977 | } |
1a4d82fc | 2978 | |
a7813a04 XL |
2979 | // Determine whether there is exactly one unique region in the set |
2980 | // of derived region bounds. If so, use that. Otherwise, report an | |
2981 | // error. | |
2982 | let r = derived_region_bounds[0]; | |
2983 | if derived_region_bounds[1..].iter().any(|r1| r != *r1) { | |
1b1a35ee | 2984 | tcx.sess.emit_err(AmbiguousLifetimeBound { span }); |
a7813a04 | 2985 | } |
ba9703b0 | 2986 | Some(r) |
1a4d82fc | 2987 | } |
a2a8927a XL |
2988 | |
2989 | fn maybe_lint_bare_trait(&self, self_ty: &hir::Ty<'_>, in_path: bool) { | |
2990 | let tcx = self.tcx(); | |
2991 | if let hir::TyKind::TraitObject([poly_trait_ref, ..], _, TraitObjectSyntax::None) = | |
2992 | self_ty.kind | |
2993 | { | |
2994 | let needs_bracket = in_path | |
2995 | && !tcx | |
2996 | .sess | |
2997 | .source_map() | |
2998 | .span_to_prev_source(self_ty.span) | |
2999 | .ok() | |
3000 | .map_or(false, |s| s.trim_end().ends_with('<')); | |
3001 | ||
3002 | let is_global = poly_trait_ref.trait_ref.path.is_global(); | |
3003 | let sugg = Vec::from_iter([ | |
3004 | ( | |
3005 | self_ty.span.shrink_to_lo(), | |
3006 | format!( | |
3007 | "{}dyn {}", | |
3008 | if needs_bracket { "<" } else { "" }, | |
3009 | if is_global { "(" } else { "" }, | |
3010 | ), | |
3011 | ), | |
3012 | ( | |
3013 | self_ty.span.shrink_to_hi(), | |
3014 | format!( | |
3015 | "{}{}", | |
3016 | if is_global { ")" } else { "" }, | |
3017 | if needs_bracket { ">" } else { "" }, | |
3018 | ), | |
3019 | ), | |
3020 | ]); | |
3021 | if self_ty.span.edition() >= Edition::Edition2021 { | |
3022 | let msg = "trait objects must include the `dyn` keyword"; | |
3023 | let label = "add `dyn` keyword before this trait"; | |
3024 | rustc_errors::struct_span_err!(tcx.sess, self_ty.span, E0782, "{}", msg) | |
3025 | .multipart_suggestion_verbose(label, sugg, Applicability::MachineApplicable) | |
3026 | .emit(); | |
3027 | } else { | |
3028 | let msg = "trait objects without an explicit `dyn` are deprecated"; | |
3029 | tcx.struct_span_lint_hir( | |
3030 | BARE_TRAIT_OBJECTS, | |
3031 | self_ty.hir_id, | |
3032 | self_ty.span, | |
3033 | |lint| { | |
3034 | lint.build(msg) | |
3035 | .multipart_suggestion_verbose( | |
3036 | "use `dyn`", | |
3037 | sugg, | |
3038 | Applicability::MachineApplicable, | |
3039 | ) | |
5e7ed085 | 3040 | .emit(); |
a2a8927a XL |
3041 | }, |
3042 | ); | |
3043 | } | |
3044 | } | |
3045 | } | |
1a4d82fc | 3046 | } |