]>
Commit | Line | Data |
---|---|---|
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::{ |
f2b60f7d FG |
19 | struct_span_err, Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed, FatalError, |
20 | MultiSpan, | |
5e7ed085 | 21 | }; |
dfeec247 | 22 | use rustc_hir as hir; |
74b04a01 | 23 | use rustc_hir::def::{CtorOf, DefKind, Namespace, Res}; |
f9f354fc | 24 | use rustc_hir::def_id::{DefId, LocalDefId}; |
ba9703b0 | 25 | use rustc_hir::intravisit::{walk_generics, Visitor as _}; |
923072b8 FG |
26 | use rustc_hir::{GenericArg, GenericArgs, OpaqueTyOrigin}; |
27 | use rustc_middle::middle::stability::AllowUnstable; | |
2b03887a | 28 | use rustc_middle::ty::subst::{self, GenericArgKind, InternalSubsts, SubstsRef}; |
f2b60f7d | 29 | use rustc_middle::ty::DynKind; |
3dfed10e | 30 | use rustc_middle::ty::GenericParamDefKind; |
923072b8 | 31 | use rustc_middle::ty::{ |
064997fb | 32 | self, Const, DefIdTree, EarlyBinder, IsSuggestable, Ty, TyCtxt, TypeVisitable, |
923072b8 | 33 | }; |
a2a8927a XL |
34 | use rustc_session::lint::builtin::{AMBIGUOUS_ASSOCIATED_ITEMS, BARE_TRAIT_OBJECTS}; |
35 | use rustc_span::edition::Edition; | |
fc512014 | 36 | use rustc_span::lev_distance::find_best_match_for_name; |
923072b8 | 37 | use rustc_span::symbol::{kw, Ident, Symbol}; |
2b03887a | 38 | use rustc_span::{sym, Span}; |
83c7162d | 39 | use rustc_target::spec::abi; |
ba9703b0 XL |
40 | use rustc_trait_selection::traits; |
41 | use rustc_trait_selection::traits::astconv_object_safety_violations; | |
064997fb FG |
42 | use rustc_trait_selection::traits::error_reporting::{ |
43 | report_object_safety_error, suggestions::NextTypeParamName, | |
44 | }; | |
ba9703b0 | 45 | use rustc_trait_selection::traits::wf::object_region_bounds; |
0731742a | 46 | |
f2b60f7d | 47 | use smallvec::{smallvec, SmallVec}; |
0731742a | 48 | use std::collections::BTreeSet; |
0731742a XL |
49 | use std::slice; |
50 | ||
0731742a XL |
51 | #[derive(Debug)] |
52 | pub struct PathSeg(pub DefId, pub usize); | |
e9174d1e | 53 | |
dc9dc135 XL |
54 | pub trait AstConv<'tcx> { |
55 | fn tcx<'a>(&'a self) -> TyCtxt<'tcx>; | |
1a4d82fc | 56 | |
487cf647 | 57 | fn item_def_id(&self) -> DefId; |
60c5eb7d | 58 | |
6a06907d XL |
59 | /// Returns predicates in scope of the form `X: Foo<T>`, where `X` |
60 | /// is a type parameter `X` with the given id `def_id` and T | |
61 | /// matches `assoc_name`. This is a subset of the full set of | |
62 | /// predicates. | |
416331ca XL |
63 | /// |
64 | /// This is used for one specific purpose: resolving "short-hand" | |
65 | /// associated type references like `T::Item`. In principle, we | |
66 | /// would do that by first getting the full set of predicates in | |
67 | /// scope and then filtering down to find those that apply to `T`, | |
68 | /// but this can lead to cycle errors. The problem is that we have | |
69 | /// to do this resolution *in order to create the predicates in | |
70 | /// the first place*. Hence, we have this "special pass". | |
6a06907d XL |
71 | fn get_type_parameter_bounds( |
72 | &self, | |
73 | span: Span, | |
74 | def_id: DefId, | |
75 | assoc_name: Ident, | |
76 | ) -> ty::GenericPredicates<'tcx>; | |
c34b1796 | 77 | |
dc9dc135 | 78 | /// Returns the lifetime to use when a lifetime is omitted (and not elided). |
dfeec247 XL |
79 | fn re_infer(&self, param: Option<&ty::GenericParamDef>, span: Span) |
80 | -> Option<ty::Region<'tcx>>; | |
32a655c1 | 81 | |
dc9dc135 XL |
82 | /// Returns the type to use when a type is omitted. |
83 | fn ty_infer(&self, param: Option<&ty::GenericParamDef>, span: Span) -> Ty<'tcx>; | |
9e0c209e | 84 | |
dfeec247 XL |
85 | /// Returns `true` if `_` is allowed in type signatures in the current context. |
86 | fn allow_ty_infer(&self) -> bool; | |
87 | ||
dc9dc135 XL |
88 | /// Returns the const to use when a const is omitted. |
89 | fn ct_infer( | |
90 | &self, | |
91 | ty: Ty<'tcx>, | |
92 | param: Option<&ty::GenericParamDef>, | |
93 | span: Span, | |
5099ac24 | 94 | ) -> Const<'tcx>; |
1a4d82fc JJ |
95 | |
96 | /// Projecting an associated type from a (potentially) | |
97 | /// higher-ranked trait reference is more complicated, because of | |
98 | /// the possibility of late-bound regions appearing in the | |
99 | /// associated type binding. This is not legal in function | |
100 | /// signatures for that reason. In a function body, we can always | |
101 | /// handle it because we can use inference variables to remove the | |
102 | /// late-bound regions. | |
dfeec247 XL |
103 | fn projected_ty_from_poly_trait_ref( |
104 | &self, | |
105 | span: Span, | |
106 | item_def_id: DefId, | |
107 | item_segment: &hir::PathSegment<'_>, | |
108 | poly_trait_ref: ty::PolyTraitRef<'tcx>, | |
109 | ) -> Ty<'tcx>; | |
1a4d82fc | 110 | |
8bb4bdeb | 111 | /// Normalize an associated type coming from the user. |
487cf647 FG |
112 | /// |
113 | /// This should only be used by astconv. Use `FnCtxt::normalize` | |
114 | /// or `ObligationCtxt::normalize` in downstream crates. | |
8bb4bdeb | 115 | fn normalize_ty(&self, span: Span, ty: Ty<'tcx>) -> Ty<'tcx>; |
a7813a04 XL |
116 | |
117 | /// Invoked when we encounter an error from some prior pass | |
0731742a | 118 | /// (e.g., resolve) that is translated into a ty-error. This is |
a7813a04 XL |
119 | /// used to help suppress derived errors typeck might otherwise |
120 | /// report. | |
487cf647 | 121 | fn set_tainted_by_errors(&self, e: ErrorGuaranteed); |
ea8adc8c XL |
122 | |
123 | fn record_ty(&self, hir_id: hir::HirId, ty: Ty<'tcx>, span: Span); | |
a7813a04 XL |
124 | } |
125 | ||
5869c6ff | 126 | #[derive(Debug)] |
dc9dc135 | 127 | struct ConvertedBinding<'a, 'tcx> { |
17df50a5 | 128 | hir_id: hir::HirId, |
f9f354fc | 129 | item_name: Ident, |
dc9dc135 | 130 | kind: ConvertedBindingKind<'a, 'tcx>, |
5869c6ff | 131 | gen_args: &'a GenericArgs<'a>, |
a7813a04 | 132 | span: Span, |
1a4d82fc JJ |
133 | } |
134 | ||
5869c6ff | 135 | #[derive(Debug)] |
dc9dc135 | 136 | enum ConvertedBindingKind<'a, 'tcx> { |
5099ac24 | 137 | Equality(ty::Term<'tcx>), |
dfeec247 | 138 | Constraint(&'a [hir::GenericBound<'a>]), |
dc9dc135 XL |
139 | } |
140 | ||
f9f354fc XL |
141 | /// New-typed boolean indicating whether explicit late-bound lifetimes |
142 | /// are present in a set of generic arguments. | |
143 | /// | |
144 | /// For example if we have some method `fn f<'a>(&'a self)` implemented | |
145 | /// for some type `T`, although `f` is generic in the lifetime `'a`, `'a` | |
146 | /// is late-bound so should not be provided explicitly. Thus, if `f` is | |
147 | /// instantiated with some generic arguments providing `'a` explicitly, | |
148 | /// we taint those arguments with `ExplicitLateBound::Yes` so that we | |
149 | /// can provide an appropriate diagnostic later. | |
f2b60f7d | 150 | #[derive(Copy, Clone, PartialEq, Debug)] |
f9f354fc XL |
151 | pub enum ExplicitLateBound { |
152 | Yes, | |
153 | No, | |
154 | } | |
155 | ||
5869c6ff XL |
156 | #[derive(Copy, Clone, PartialEq)] |
157 | pub enum IsMethodCall { | |
158 | Yes, | |
159 | No, | |
160 | } | |
161 | ||
3dfed10e XL |
162 | /// Denotes the "position" of a generic argument, indicating if it is a generic type, |
163 | /// generic function or generic method call. | |
f9f354fc | 164 | #[derive(Copy, Clone, PartialEq)] |
3dfed10e | 165 | pub(crate) enum GenericArgPosition { |
b7449926 | 166 | Type, |
0731742a | 167 | Value, // e.g., functions |
b7449926 | 168 | MethodCall, |
94b46f34 XL |
169 | } |
170 | ||
74b04a01 XL |
171 | /// A marker denoting that the generic arguments that were |
172 | /// provided did not match the respective generic parameters. | |
f2b60f7d | 173 | #[derive(Clone, Default, Debug)] |
74b04a01 XL |
174 | pub struct GenericArgCountMismatch { |
175 | /// Indicates whether a fatal error was reported (`Some`), or just a lint (`None`). | |
5e7ed085 | 176 | pub reported: Option<ErrorGuaranteed>, |
74b04a01 XL |
177 | /// A list of spans of arguments provided that were not valid. |
178 | pub invalid_args: Vec<Span>, | |
179 | } | |
180 | ||
f9f354fc XL |
181 | /// Decorates the result of a generic argument count mismatch |
182 | /// check with whether explicit late bounds were provided. | |
f2b60f7d | 183 | #[derive(Clone, Debug)] |
f9f354fc XL |
184 | pub struct GenericArgCountResult { |
185 | pub explicit_late_bound: ExplicitLateBound, | |
186 | pub correct: Result<(), GenericArgCountMismatch>, | |
187 | } | |
188 | ||
fc512014 XL |
189 | pub trait CreateSubstsForGenericArgsCtxt<'a, 'tcx> { |
190 | fn args_for_def_id(&mut self, def_id: DefId) -> (Option<&'a GenericArgs<'a>>, bool); | |
191 | ||
192 | fn provided_kind( | |
193 | &mut self, | |
194 | param: &ty::GenericParamDef, | |
195 | arg: &GenericArg<'_>, | |
196 | ) -> subst::GenericArg<'tcx>; | |
197 | ||
198 | fn inferred_kind( | |
199 | &mut self, | |
200 | substs: Option<&[subst::GenericArg<'tcx>]>, | |
201 | param: &ty::GenericParamDef, | |
202 | infer_args: bool, | |
203 | ) -> subst::GenericArg<'tcx>; | |
204 | } | |
205 | ||
dc9dc135 | 206 | impl<'o, 'tcx> dyn AstConv<'tcx> + 'o { |
f2b60f7d | 207 | #[instrument(level = "debug", skip(self), ret)] |
dfeec247 XL |
208 | pub fn ast_region_to_region( |
209 | &self, | |
32a655c1 | 210 | lifetime: &hir::Lifetime, |
dfeec247 XL |
211 | def: Option<&ty::GenericParamDef>, |
212 | ) -> ty::Region<'tcx> { | |
32a655c1 | 213 | let tcx = self.tcx(); |
3dfed10e | 214 | let lifetime_name = |def_id| tcx.hir().name(tcx.hir().local_def_id_to_hir_id(def_id)); |
ea8adc8c | 215 | |
f2b60f7d | 216 | match tcx.named_region(lifetime.hir_id) { |
dfeec247 | 217 | Some(rl::Region::Static) => tcx.lifetimes.re_static, |
32a655c1 | 218 | |
5e7ed085 | 219 | Some(rl::Region::LateBound(debruijn, index, def_id)) => { |
cdc7bbd5 XL |
220 | let name = lifetime_name(def_id.expect_local()); |
221 | let br = ty::BoundRegion { | |
222 | var: ty::BoundVar::from_u32(index), | |
223 | kind: ty::BrNamed(def_id, name), | |
224 | }; | |
fc512014 | 225 | tcx.mk_region(ty::ReLateBound(debruijn, br)) |
32a655c1 SL |
226 | } |
227 | ||
f2b60f7d FG |
228 | Some(rl::Region::EarlyBound(def_id)) => { |
229 | let name = tcx.hir().ty_param_name(def_id.expect_local()); | |
230 | let item_def_id = tcx.hir().ty_param_owner(def_id.expect_local()); | |
231 | let generics = tcx.generics_of(item_def_id); | |
232 | let index = generics.param_def_id_to_index[&def_id]; | |
233 | tcx.mk_region(ty::ReEarlyBound(ty::EarlyBoundRegion { def_id, index, name })) | |
32a655c1 SL |
234 | } |
235 | ||
ea8adc8c | 236 | Some(rl::Region::Free(scope, id)) => { |
f9f354fc | 237 | let name = lifetime_name(id.expect_local()); |
32a655c1 | 238 | tcx.mk_region(ty::ReFree(ty::FreeRegion { |
7cac9316 | 239 | scope, |
dfeec247 | 240 | bound_region: ty::BrNamed(id, name), |
32a655c1 | 241 | })) |
5bcae85e | 242 | |
0bf4aa26 | 243 | // (*) -- not late-bound, won't change |
32a655c1 | 244 | } |
5bcae85e | 245 | |
32a655c1 | 246 | None => { |
487cf647 | 247 | self.re_infer(def, lifetime.ident.span).unwrap_or_else(|| { |
cdc7bbd5 XL |
248 | debug!(?lifetime, "unelided lifetime in signature"); |
249 | ||
dfeec247 XL |
250 | // This indicates an illegal lifetime |
251 | // elision. `resolve_lifetime` should have | |
252 | // reported an error in this case -- but if | |
253 | // not, let's error out. | |
487cf647 | 254 | tcx.sess.delay_span_bug(lifetime.ident.span, "unelided lifetime in signature"); |
dfeec247 XL |
255 | |
256 | // Supply some dummy value. We don't have an | |
257 | // `re_error`, annoyingly, so use `'static`. | |
258 | tcx.lifetimes.re_static | |
259 | }) | |
32a655c1 | 260 | } |
f2b60f7d | 261 | } |
a7813a04 | 262 | } |
1a4d82fc | 263 | |
a7813a04 XL |
264 | /// Given a path `path` that refers to an item `I` with the declared generics `decl_generics`, |
265 | /// returns an appropriate set of substitutions for this particular reference to `I`. | |
dfeec247 XL |
266 | pub fn ast_path_substs_for_ty( |
267 | &self, | |
a7813a04 | 268 | span: Span, |
9e0c209e | 269 | def_id: DefId, |
dfeec247 XL |
270 | item_segment: &hir::PathSegment<'_>, |
271 | ) -> SubstsRef<'tcx> { | |
cdc7bbd5 | 272 | let (substs, _) = self.create_substs_for_ast_path( |
dc9dc135 XL |
273 | span, |
274 | def_id, | |
dfeec247 | 275 | &[], |
5869c6ff XL |
276 | item_segment, |
277 | item_segment.args(), | |
dc9dc135 XL |
278 | item_segment.infer_args, |
279 | None, | |
487cf647 | 280 | ty::BoundConstness::NotConst, |
dc9dc135 | 281 | ); |
2b03887a | 282 | if let Some(b) = item_segment.args().bindings.first() { |
f9f354fc XL |
283 | Self::prohibit_assoc_ty_binding(self.tcx(), b.span); |
284 | } | |
1a4d82fc | 285 | |
9e0c209e | 286 | substs |
a7813a04 | 287 | } |
c34b1796 | 288 | |
48663c56 | 289 | /// Given the type/lifetime/const arguments provided to some path (along with |
dc9dc135 | 290 | /// an implicit `Self`, if this is a trait reference), returns the complete |
9e0c209e | 291 | /// set of substitutions. This may involve applying defaulted type parameters. |
5e7ed085 | 292 | /// Constraints on associated types are created from `create_assoc_bindings_for_generic_args`. |
dc9dc135 XL |
293 | /// |
294 | /// Example: | |
295 | /// | |
04454e1e FG |
296 | /// ```ignore (illustrative) |
297 | /// T: std::ops::Index<usize, Output = u32> | |
298 | /// // ^1 ^^^^^^^^^^^^^^2 ^^^^3 ^^^^^^^^^^^4 | |
dc9dc135 XL |
299 | /// ``` |
300 | /// | |
301 | /// 1. The `self_ty` here would refer to the type `T`. | |
302 | /// 2. The path in question is the path to the trait `std::ops::Index`, | |
303 | /// which will have been resolved to a `def_id` | |
304 | /// 3. The `generic_args` contains info on the `<...>` contents. The `usize` type | |
305 | /// parameters are returned in the `SubstsRef`, the associated type bindings like | |
5099ac24 | 306 | /// `Output = u32` are returned from `create_assoc_bindings_for_generic_args`. |
9e0c209e SL |
307 | /// |
308 | /// Note that the type listing given here is *exactly* what the user provided. | |
dfeec247 XL |
309 | /// |
310 | /// For (generic) associated types | |
311 | /// | |
04454e1e | 312 | /// ```ignore (illustrative) |
dfeec247 XL |
313 | /// <Vec<u8> as Iterable<u8>>::Iter::<'a> |
314 | /// ``` | |
315 | /// | |
316 | /// We have the parent substs are the substs for the parent trait: | |
317 | /// `[Vec<u8>, u8]` and `generic_args` are the arguments for the associated | |
318 | /// type itself: `['a]`. The returned `SubstsRef` concatenates these two | |
319 | /// lists: `[Vec<u8>, u8, 'a]`. | |
f2b60f7d | 320 | #[instrument(level = "debug", skip(self, span), ret)] |
dfeec247 XL |
321 | fn create_substs_for_ast_path<'a>( |
322 | &self, | |
a7813a04 | 323 | span: Span, |
9e0c209e | 324 | def_id: DefId, |
dfeec247 | 325 | parent_substs: &[subst::GenericArg<'tcx>], |
5869c6ff | 326 | seg: &hir::PathSegment<'_>, |
dfeec247 | 327 | generic_args: &'a hir::GenericArgs<'_>, |
dc9dc135 | 328 | infer_args: bool, |
dfeec247 | 329 | self_ty: Option<Ty<'tcx>>, |
487cf647 | 330 | constness: ty::BoundConstness, |
cdc7bbd5 | 331 | ) -> (SubstsRef<'tcx>, GenericArgCountResult) { |
a7813a04 XL |
332 | // If the type is parameterized by this region, then replace this |
333 | // region with the current anon region binding (in other words, | |
334 | // whatever & would get replaced with). | |
94b46f34 | 335 | |
b7449926 | 336 | let tcx = self.tcx(); |
5869c6ff XL |
337 | let generics = tcx.generics_of(def_id); |
338 | debug!("generics: {:?}", generics); | |
85aaf69f | 339 | |
5869c6ff XL |
340 | if generics.has_self { |
341 | if generics.parent.is_some() { | |
dfeec247 XL |
342 | // The parent is a trait so it should have at least one subst |
343 | // for the `Self` type. | |
344 | assert!(!parent_substs.is_empty()) | |
345 | } else { | |
346 | // This item (presumably a trait) needs a self-type. | |
347 | assert!(self_ty.is_some()); | |
348 | } | |
349 | } else { | |
487cf647 | 350 | assert!(self_ty.is_none()); |
dfeec247 | 351 | } |
a7813a04 | 352 | |
f9f354fc | 353 | let arg_count = Self::check_generic_arg_count( |
0731742a | 354 | tcx, |
b7449926 | 355 | span, |
5869c6ff XL |
356 | def_id, |
357 | seg, | |
c295e0f8 XL |
358 | generics, |
359 | generic_args, | |
b7449926 | 360 | GenericArgPosition::Type, |
dfeec247 | 361 | self_ty.is_some(), |
dc9dc135 | 362 | infer_args, |
b7449926 | 363 | ); |
1a4d82fc | 364 | |
fc512014 XL |
365 | // Skip processing if type has no generic parameters. |
366 | // Traits always have `Self` as a generic parameter, which means they will not return early | |
367 | // here and so associated type bindings will be handled regardless of whether there are any | |
368 | // non-`Self` generic parameters. | |
c295e0f8 | 369 | if generics.params.is_empty() { |
2b03887a | 370 | return (tcx.intern_substs(parent_substs), arg_count); |
fc512014 XL |
371 | } |
372 | ||
fc512014 XL |
373 | struct SubstsForAstPathCtxt<'a, 'tcx> { |
374 | astconv: &'a (dyn AstConv<'tcx> + 'a), | |
375 | def_id: DefId, | |
376 | generic_args: &'a GenericArgs<'a>, | |
377 | span: Span, | |
fc512014 XL |
378 | inferred_params: Vec<Span>, |
379 | infer_args: bool, | |
fc512014 | 380 | } |
9e0c209e | 381 | |
fc512014 XL |
382 | impl<'a, 'tcx> CreateSubstsForGenericArgsCtxt<'a, 'tcx> for SubstsForAstPathCtxt<'a, 'tcx> { |
383 | fn args_for_def_id(&mut self, did: DefId) -> (Option<&'a GenericArgs<'a>>, bool) { | |
384 | if did == self.def_id { | |
385 | (Some(self.generic_args), self.infer_args) | |
74b04a01 XL |
386 | } else { |
387 | // The last component of this tuple is unimportant. | |
388 | (None, false) | |
389 | } | |
fc512014 XL |
390 | } |
391 | ||
392 | fn provided_kind( | |
393 | &mut self, | |
394 | param: &ty::GenericParamDef, | |
395 | arg: &GenericArg<'_>, | |
396 | ) -> subst::GenericArg<'tcx> { | |
397 | let tcx = self.astconv.tcx(); | |
a2a8927a XL |
398 | |
399 | let mut handle_ty_args = |has_default, ty: &hir::Ty<'_>| { | |
400 | if has_default { | |
401 | tcx.check_optional_stability( | |
402 | param.def_id, | |
f2b60f7d | 403 | Some(arg.hir_id()), |
a2a8927a XL |
404 | arg.span(), |
405 | None, | |
923072b8 | 406 | AllowUnstable::No, |
a2a8927a XL |
407 | |_, _| { |
408 | // Default generic parameters may not be marked | |
409 | // with stability attributes, i.e. when the | |
410 | // default parameter was defined at the same time | |
411 | // as the rest of the type. As such, we ignore missing | |
412 | // stability attributes. | |
413 | }, | |
064997fb | 414 | ); |
a2a8927a XL |
415 | } |
416 | if let (hir::TyKind::Infer, false) = (&ty.kind, self.astconv.allow_ty_infer()) { | |
417 | self.inferred_params.push(ty.span); | |
418 | tcx.ty_error().into() | |
419 | } else { | |
420 | self.astconv.ast_ty_to_ty(ty).into() | |
421 | } | |
422 | }; | |
423 | ||
fc512014 XL |
424 | match (¶m.kind, arg) { |
425 | (GenericParamDefKind::Lifetime, GenericArg::Lifetime(lt)) => { | |
c295e0f8 | 426 | self.astconv.ast_region_to_region(lt, Some(param)).into() |
fc512014 XL |
427 | } |
428 | (&GenericParamDefKind::Type { has_default, .. }, GenericArg::Type(ty)) => { | |
a2a8927a XL |
429 | handle_ty_args(has_default, ty) |
430 | } | |
431 | (&GenericParamDefKind::Type { has_default, .. }, GenericArg::Infer(inf)) => { | |
432 | handle_ty_args(has_default, &inf.to_ty()) | |
fc512014 | 433 | } |
cdc7bbd5 | 434 | (GenericParamDefKind::Const { .. }, GenericArg::Const(ct)) => { |
fc512014 XL |
435 | ty::Const::from_opt_const_arg_anon_const( |
436 | tcx, | |
437 | ty::WithOptConstParam { | |
487cf647 | 438 | did: ct.value.def_id, |
fc512014 | 439 | const_param_did: Some(param.def_id), |
1b1a35ee XL |
440 | }, |
441 | ) | |
fc512014 | 442 | .into() |
1b1a35ee | 443 | } |
a2a8927a XL |
444 | (&GenericParamDefKind::Const { .. }, hir::GenericArg::Infer(inf)) => { |
445 | let ty = tcx.at(self.span).type_of(param.def_id); | |
94222f64 | 446 | if self.astconv.allow_ty_infer() { |
a2a8927a | 447 | self.astconv.ct_infer(ty, Some(param), inf.span).into() |
94222f64 XL |
448 | } else { |
449 | self.inferred_params.push(inf.span); | |
a2a8927a | 450 | tcx.const_error(ty).into() |
94222f64 XL |
451 | } |
452 | } | |
fc512014 | 453 | _ => unreachable!(), |
dfeec247 | 454 | } |
fc512014 XL |
455 | } |
456 | ||
457 | fn inferred_kind( | |
458 | &mut self, | |
459 | substs: Option<&[subst::GenericArg<'tcx>]>, | |
460 | param: &ty::GenericParamDef, | |
461 | infer_args: bool, | |
462 | ) -> subst::GenericArg<'tcx> { | |
463 | let tcx = self.astconv.tcx(); | |
b7449926 | 464 | match param.kind { |
5099ac24 FG |
465 | GenericParamDefKind::Lifetime => self |
466 | .astconv | |
467 | .re_infer(Some(param), self.span) | |
468 | .unwrap_or_else(|| { | |
469 | debug!(?param, "unelided lifetime in signature"); | |
470 | ||
471 | // This indicates an illegal lifetime in a non-assoc-trait position | |
472 | tcx.sess.delay_span_bug(self.span, "unelided lifetime in signature"); | |
473 | ||
474 | // Supply some dummy value. We don't have an | |
475 | // `re_error`, annoyingly, so use `'static`. | |
476 | tcx.lifetimes.re_static | |
477 | }) | |
478 | .into(), | |
b7449926 | 479 | GenericParamDefKind::Type { has_default, .. } => { |
dc9dc135 | 480 | if !infer_args && has_default { |
b7449926 | 481 | // No type parameter provided, but a default exists. |
f2b60f7d FG |
482 | let substs = substs.unwrap(); |
483 | if substs.iter().any(|arg| match arg.unpack() { | |
484 | GenericArgKind::Type(ty) => ty.references_error(), | |
485 | _ => false, | |
486 | }) { | |
487 | // Avoid ICE #86756 when type error recovery goes awry. | |
488 | return tcx.ty_error().into(); | |
b7449926 | 489 | } |
f2b60f7d FG |
490 | self.astconv |
491 | .normalize_ty( | |
492 | self.span, | |
493 | EarlyBinder(tcx.at(self.span).type_of(param.def_id)) | |
494 | .subst(tcx, substs), | |
495 | ) | |
496 | .into() | |
dc9dc135 | 497 | } else if infer_args { |
f2b60f7d | 498 | self.astconv.ty_infer(Some(param), self.span).into() |
94b46f34 | 499 | } else { |
b7449926 | 500 | // We've already errored above about the mismatch. |
f035d41b | 501 | tcx.ty_error().into() |
94b46f34 | 502 | } |
94b46f34 | 503 | } |
cdc7bbd5 | 504 | GenericParamDefKind::Const { has_default } => { |
fc512014 | 505 | let ty = tcx.at(self.span).type_of(param.def_id); |
487cf647 FG |
506 | if ty.references_error() { |
507 | return tcx.const_error(ty).into(); | |
508 | } | |
cdc7bbd5 | 509 | if !infer_args && has_default { |
064997fb | 510 | tcx.bound_const_param_default(param.def_id) |
04454e1e | 511 | .subst(tcx, substs.unwrap()) |
cdc7bbd5 | 512 | .into() |
dc9dc135 | 513 | } else { |
cdc7bbd5 XL |
514 | if infer_args { |
515 | self.astconv.ct_infer(ty, Some(param), self.span).into() | |
516 | } else { | |
517 | // We've already errored above about the mismatch. | |
518 | tcx.const_error(ty).into() | |
519 | } | |
dc9dc135 | 520 | } |
532ac7d7 | 521 | } |
a7813a04 | 522 | } |
fc512014 XL |
523 | } |
524 | } | |
525 | ||
526 | let mut substs_ctx = SubstsForAstPathCtxt { | |
527 | astconv: self, | |
528 | def_id, | |
529 | span, | |
530 | generic_args, | |
fc512014 XL |
531 | inferred_params: vec![], |
532 | infer_args, | |
fc512014 XL |
533 | }; |
534 | let substs = Self::create_substs_for_generic_args( | |
535 | tcx, | |
536 | def_id, | |
537 | parent_substs, | |
538 | self_ty.is_some(), | |
539 | self_ty, | |
cdc7bbd5 | 540 | &arg_count, |
fc512014 | 541 | &mut substs_ctx, |
b7449926 | 542 | ); |
1a4d82fc | 543 | |
487cf647 | 544 | if let ty::BoundConstness::ConstIfConst = constness |
2b03887a FG |
545 | && generics.has_self && !tcx.has_attr(def_id, sym::const_trait) |
546 | { | |
547 | tcx.sess.emit_err(crate::errors::ConstBoundForNonConstTrait { span } ); | |
548 | } | |
549 | ||
cdc7bbd5 XL |
550 | (substs, arg_count) |
551 | } | |
552 | ||
553 | fn create_assoc_bindings_for_generic_args<'a>( | |
554 | &self, | |
555 | generic_args: &'a hir::GenericArgs<'_>, | |
556 | ) -> Vec<ConvertedBinding<'a, 'tcx>> { | |
dc9dc135 XL |
557 | // Convert associated-type bindings or constraints into a separate vector. |
558 | // Example: Given this: | |
559 | // | |
560 | // T: Iterator<Item = u32> | |
561 | // | |
562 | // The `T` is passed in as a self-type; the `Item = u32` is | |
563 | // not a "type parameter" of the `Iterator` trait, but rather | |
564 | // a restriction on `<T as Iterator>::Item`, so it is passed | |
565 | // back separately. | |
dfeec247 XL |
566 | let assoc_bindings = generic_args |
567 | .bindings | |
568 | .iter() | |
dc9dc135 XL |
569 | .map(|binding| { |
570 | let kind = match binding.kind { | |
5099ac24 FG |
571 | hir::TypeBindingKind::Equality { ref term } => match term { |
572 | hir::Term::Ty(ref ty) => { | |
573 | ConvertedBindingKind::Equality(self.ast_ty_to_ty(ty).into()) | |
574 | } | |
575 | hir::Term::Const(ref c) => { | |
487cf647 | 576 | let c = Const::from_anon_const(self.tcx(), c.def_id); |
5099ac24 FG |
577 | ConvertedBindingKind::Equality(c.into()) |
578 | } | |
579 | }, | |
580 | hir::TypeBindingKind::Constraint { ref bounds } => { | |
dfeec247 XL |
581 | ConvertedBindingKind::Constraint(bounds) |
582 | } | |
dc9dc135 | 583 | }; |
5869c6ff | 584 | ConvertedBinding { |
17df50a5 | 585 | hir_id: binding.hir_id, |
5869c6ff XL |
586 | item_name: binding.ident, |
587 | kind, | |
588 | gen_args: binding.gen_args, | |
589 | span: binding.span, | |
590 | } | |
dc9dc135 XL |
591 | }) |
592 | .collect(); | |
a7813a04 | 593 | |
cdc7bbd5 | 594 | assoc_bindings |
e9174d1e | 595 | } |
e9174d1e | 596 | |
2b03887a | 597 | pub fn create_substs_for_associated_item( |
dfeec247 | 598 | &self, |
dfeec247 XL |
599 | span: Span, |
600 | item_def_id: DefId, | |
601 | item_segment: &hir::PathSegment<'_>, | |
602 | parent_substs: SubstsRef<'tcx>, | |
603 | ) -> SubstsRef<'tcx> { | |
17df50a5 XL |
604 | debug!( |
605 | "create_substs_for_associated_item(span: {:?}, item_def_id: {:?}, item_segment: {:?}", | |
606 | span, item_def_id, item_segment | |
607 | ); | |
2b03887a FG |
608 | let (args, _) = self.create_substs_for_ast_path( |
609 | span, | |
610 | item_def_id, | |
611 | parent_substs, | |
612 | item_segment, | |
613 | item_segment.args(), | |
614 | item_segment.infer_args, | |
615 | None, | |
487cf647 | 616 | ty::BoundConstness::NotConst, |
2b03887a | 617 | ); |
f2b60f7d | 618 | |
2b03887a FG |
619 | if let Some(b) = item_segment.args().bindings.first() { |
620 | Self::prohibit_assoc_ty_binding(self.tcx(), b.span); | |
dfeec247 | 621 | } |
2b03887a FG |
622 | |
623 | args | |
dfeec247 XL |
624 | } |
625 | ||
a7813a04 | 626 | /// Instantiates the path for the given trait reference, assuming that it's |
dc9dc135 | 627 | /// bound to a valid trait type. Returns the `DefId` of the defining trait. |
0531ce1d | 628 | /// The type _cannot_ be a type other than a trait type. |
a7813a04 | 629 | /// |
9fa01778 | 630 | /// If the `projections` argument is `None`, then assoc type bindings like `Foo<T = X>` |
a7813a04 | 631 | /// are disallowed. Otherwise, they are pushed onto the vector given. |
dfeec247 XL |
632 | pub fn instantiate_mono_trait_ref( |
633 | &self, | |
634 | trait_ref: &hir::TraitRef<'_>, | |
635 | self_ty: Ty<'tcx>, | |
2b03887a | 636 | constness: ty::BoundConstness, |
dfeec247 | 637 | ) -> ty::TraitRef<'tcx> { |
923072b8 | 638 | self.prohibit_generics(trait_ref.path.segments.split_last().unwrap().1.iter(), |_| {}); |
7cac9316 | 639 | |
dfeec247 XL |
640 | self.ast_path_to_mono_trait_ref( |
641 | trait_ref.path.span, | |
ba9703b0 | 642 | trait_ref.trait_def_id().unwrap_or_else(|| FatalError.raise()), |
dfeec247 XL |
643 | self_ty, |
644 | trait_ref.path.segments.last().unwrap(), | |
5099ac24 | 645 | true, |
487cf647 | 646 | constness, |
dfeec247 | 647 | ) |
1a4d82fc | 648 | } |
c34b1796 | 649 | |
c295e0f8 XL |
650 | fn instantiate_poly_trait_ref_inner( |
651 | &self, | |
652 | hir_id: hir::HirId, | |
653 | span: Span, | |
654 | binding_span: Option<Span>, | |
655 | constness: ty::BoundConstness, | |
656 | bounds: &mut Bounds<'tcx>, | |
657 | speculative: bool, | |
658 | trait_ref_span: Span, | |
659 | trait_def_id: DefId, | |
660 | trait_segment: &hir::PathSegment<'_>, | |
661 | args: &GenericArgs<'_>, | |
662 | infer_args: bool, | |
663 | self_ty: Ty<'tcx>, | |
664 | ) -> GenericArgCountResult { | |
665 | let (substs, arg_count) = self.create_substs_for_ast_path( | |
666 | trait_ref_span, | |
667 | trait_def_id, | |
668 | &[], | |
669 | trait_segment, | |
670 | args, | |
671 | infer_args, | |
672 | Some(self_ty), | |
487cf647 | 673 | constness, |
c295e0f8 XL |
674 | ); |
675 | ||
676 | let tcx = self.tcx(); | |
677 | let bound_vars = tcx.late_bound_vars(hir_id); | |
678 | debug!(?bound_vars); | |
679 | ||
680 | let assoc_bindings = self.create_assoc_bindings_for_generic_args(args); | |
681 | ||
682 | let poly_trait_ref = | |
683 | ty::Binder::bind_with_vars(ty::TraitRef::new(trait_def_id, substs), bound_vars); | |
684 | ||
685 | debug!(?poly_trait_ref, ?assoc_bindings); | |
686 | bounds.trait_bounds.push((poly_trait_ref, span, constness)); | |
687 | ||
688 | let mut dup_bindings = FxHashMap::default(); | |
689 | for binding in &assoc_bindings { | |
690 | // Specify type to assert that error was already reported in `Err` case. | |
5e7ed085 | 691 | let _: Result<_, ErrorGuaranteed> = self.add_predicates_for_ast_type_binding( |
c295e0f8 XL |
692 | hir_id, |
693 | poly_trait_ref, | |
694 | binding, | |
695 | bounds, | |
696 | speculative, | |
697 | &mut dup_bindings, | |
698 | binding_span.unwrap_or(binding.span), | |
2b03887a | 699 | constness, |
c295e0f8 | 700 | ); |
5e7ed085 | 701 | // Okay to ignore `Err` because of `ErrorGuaranteed` (see above). |
c295e0f8 XL |
702 | } |
703 | ||
704 | arg_count | |
705 | } | |
706 | ||
cdc7bbd5 XL |
707 | /// Given a trait bound like `Debug`, applies that trait bound the given self-type to construct |
708 | /// a full trait reference. The resulting trait reference is returned. This may also generate | |
709 | /// auxiliary bounds, which are added to `bounds`. | |
710 | /// | |
711 | /// Example: | |
712 | /// | |
04454e1e | 713 | /// ```ignore (illustrative) |
cdc7bbd5 XL |
714 | /// poly_trait_ref = Iterator<Item = u32> |
715 | /// self_ty = Foo | |
716 | /// ``` | |
717 | /// | |
718 | /// this would return `Foo: Iterator` and add `<Foo as Iterator>::Item = u32` into `bounds`. | |
719 | /// | |
720 | /// **A note on binders:** against our usual convention, there is an implied bounder around | |
721 | /// the `self_ty` and `poly_trait_ref` parameters here. So they may reference bound regions. | |
722 | /// If for example you had `for<'a> Foo<'a>: Bar<'a>`, then the `self_ty` would be `Foo<'a>` | |
723 | /// where `'a` is a bound region at depth 0. Similarly, the `poly_trait_ref` would be | |
724 | /// `Bar<'a>`. The returned poly-trait-ref will have this binder instantiated explicitly, | |
725 | /// however. | |
f2b60f7d | 726 | #[instrument(level = "debug", skip(self, span, constness, bounds, speculative))] |
c295e0f8 | 727 | pub(crate) fn instantiate_poly_trait_ref( |
dfeec247 XL |
728 | &self, |
729 | trait_ref: &hir::TraitRef<'_>, | |
416331ca | 730 | span: Span, |
94222f64 | 731 | constness: ty::BoundConstness, |
9e0c209e | 732 | self_ty: Ty<'tcx>, |
dc9dc135 XL |
733 | bounds: &mut Bounds<'tcx>, |
734 | speculative: bool, | |
f9f354fc | 735 | ) -> GenericArgCountResult { |
c295e0f8 XL |
736 | let hir_id = trait_ref.hir_ref_id; |
737 | let binding_span = None; | |
738 | let trait_ref_span = trait_ref.path.span; | |
ba9703b0 | 739 | let trait_def_id = trait_ref.trait_def_id().unwrap_or_else(|| FatalError.raise()); |
c295e0f8 XL |
740 | let trait_segment = trait_ref.path.segments.last().unwrap(); |
741 | let args = trait_segment.args(); | |
742 | let infer_args = trait_segment.infer_args; | |
32a655c1 | 743 | |
923072b8 | 744 | self.prohibit_generics(trait_ref.path.segments.split_last().unwrap().1.iter(), |_| {}); |
5099ac24 | 745 | self.complain_about_internal_fn_trait(span, trait_def_id, trait_segment, false); |
7cac9316 | 746 | |
c295e0f8 XL |
747 | self.instantiate_poly_trait_ref_inner( |
748 | hir_id, | |
749 | span, | |
750 | binding_span, | |
751 | constness, | |
752 | bounds, | |
753 | speculative, | |
754 | trait_ref_span, | |
a1dfa0c6 | 755 | trait_def_id, |
c295e0f8 XL |
756 | trait_segment, |
757 | args, | |
758 | infer_args, | |
a1dfa0c6 | 759 | self_ty, |
c295e0f8 | 760 | ) |
c34b1796 AL |
761 | } |
762 | ||
c295e0f8 | 763 | pub(crate) fn instantiate_lang_item_trait_ref( |
3dfed10e XL |
764 | &self, |
765 | lang_item: hir::LangItem, | |
766 | span: Span, | |
767 | hir_id: hir::HirId, | |
768 | args: &GenericArgs<'_>, | |
769 | self_ty: Ty<'tcx>, | |
770 | bounds: &mut Bounds<'tcx>, | |
771 | ) { | |
c295e0f8 XL |
772 | let binding_span = Some(span); |
773 | let constness = ty::BoundConstness::NotConst; | |
774 | let speculative = false; | |
775 | let trait_ref_span = span; | |
3dfed10e | 776 | let trait_def_id = self.tcx().require_lang_item(lang_item, Some(span)); |
c295e0f8 XL |
777 | let trait_segment = &hir::PathSegment::invalid(); |
778 | let infer_args = false; | |
3dfed10e | 779 | |
c295e0f8 XL |
780 | self.instantiate_poly_trait_ref_inner( |
781 | hir_id, | |
5869c6ff | 782 | span, |
c295e0f8 XL |
783 | binding_span, |
784 | constness, | |
785 | bounds, | |
786 | speculative, | |
787 | trait_ref_span, | |
5869c6ff | 788 | trait_def_id, |
c295e0f8 | 789 | trait_segment, |
5869c6ff | 790 | args, |
c295e0f8 XL |
791 | infer_args, |
792 | self_ty, | |
5869c6ff | 793 | ); |
3dfed10e XL |
794 | } |
795 | ||
dfeec247 XL |
796 | fn ast_path_to_mono_trait_ref( |
797 | &self, | |
dc9dc135 XL |
798 | span: Span, |
799 | trait_def_id: DefId, | |
800 | self_ty: Ty<'tcx>, | |
dfeec247 | 801 | trait_segment: &hir::PathSegment<'_>, |
5099ac24 | 802 | is_impl: bool, |
487cf647 | 803 | constness: ty::BoundConstness, |
dfeec247 | 804 | ) -> ty::TraitRef<'tcx> { |
5099ac24 FG |
805 | let (substs, _) = self.create_substs_for_ast_trait_ref( |
806 | span, | |
807 | trait_def_id, | |
808 | self_ty, | |
809 | trait_segment, | |
810 | is_impl, | |
2b03887a | 811 | constness, |
5099ac24 | 812 | ); |
2b03887a | 813 | if let Some(b) = trait_segment.args().bindings.first() { |
3dfed10e | 814 | Self::prohibit_assoc_ty_binding(self.tcx(), b.span); |
f9f354fc | 815 | } |
a7813a04 XL |
816 | ty::TraitRef::new(trait_def_id, substs) |
817 | } | |
c34b1796 | 818 | |
f2b60f7d | 819 | #[instrument(level = "debug", skip(self, span))] |
dfeec247 XL |
820 | fn create_substs_for_ast_trait_ref<'a>( |
821 | &self, | |
822 | span: Span, | |
823 | trait_def_id: DefId, | |
824 | self_ty: Ty<'tcx>, | |
825 | trait_segment: &'a hir::PathSegment<'a>, | |
5099ac24 | 826 | is_impl: bool, |
487cf647 | 827 | constness: ty::BoundConstness, |
cdc7bbd5 | 828 | ) -> (SubstsRef<'tcx>, GenericArgCountResult) { |
5099ac24 | 829 | self.complain_about_internal_fn_trait(span, trait_def_id, trait_segment, is_impl); |
dfeec247 XL |
830 | |
831 | self.create_substs_for_ast_path( | |
832 | span, | |
833 | trait_def_id, | |
834 | &[], | |
5869c6ff XL |
835 | trait_segment, |
836 | trait_segment.args(), | |
dfeec247 XL |
837 | trait_segment.infer_args, |
838 | Some(self_ty), | |
2b03887a | 839 | constness, |
dfeec247 | 840 | ) |
a7813a04 | 841 | } |
1a4d82fc | 842 | |
f9f354fc | 843 | fn trait_defines_associated_type_named(&self, trait_def_id: DefId, assoc_name: Ident) -> bool { |
74b04a01 XL |
844 | self.tcx() |
845 | .associated_items(trait_def_id) | |
846 | .find_by_name_and_kind(self.tcx(), assoc_name, ty::AssocKind::Type, trait_def_id) | |
847 | .is_some() | |
476ff2be | 848 | } |
5099ac24 FG |
849 | fn trait_defines_associated_const_named(&self, trait_def_id: DefId, assoc_name: Ident) -> bool { |
850 | self.tcx() | |
851 | .associated_items(trait_def_id) | |
852 | .find_by_name_and_kind(self.tcx(), assoc_name, ty::AssocKind::Const, trait_def_id) | |
853 | .is_some() | |
854 | } | |
476ff2be | 855 | |
487cf647 | 856 | /// Sets `implicitly_sized` to true on `Bounds` if necessary |
c295e0f8 XL |
857 | pub(crate) fn add_implicitly_sized<'hir>( |
858 | &self, | |
859 | bounds: &mut Bounds<'hir>, | |
860 | ast_bounds: &'hir [hir::GenericBound<'hir>], | |
487cf647 | 861 | self_ty_where_predicates: Option<(LocalDefId, &'hir [hir::WherePredicate<'hir>])>, |
c295e0f8 XL |
862 | span: Span, |
863 | ) { | |
dc9dc135 XL |
864 | let tcx = self.tcx(); |
865 | ||
866 | // Try to find an unbound in bounds. | |
867 | let mut unbound = None; | |
c295e0f8 XL |
868 | let mut search_bounds = |ast_bounds: &'hir [hir::GenericBound<'hir>]| { |
869 | for ab in ast_bounds { | |
870 | if let hir::GenericBound::Trait(ptr, hir::TraitBoundModifier::Maybe) = ab { | |
871 | if unbound.is_none() { | |
872 | unbound = Some(&ptr.trait_ref); | |
873 | } else { | |
874 | tcx.sess.emit_err(MultipleRelaxedDefaultBounds { span }); | |
875 | } | |
dc9dc135 XL |
876 | } |
877 | } | |
c295e0f8 XL |
878 | }; |
879 | search_bounds(ast_bounds); | |
880 | if let Some((self_ty, where_clause)) = self_ty_where_predicates { | |
c295e0f8 XL |
881 | for clause in where_clause { |
882 | if let hir::WherePredicate::BoundPredicate(pred) = clause { | |
487cf647 | 883 | if pred.is_param_bound(self_ty.to_def_id()) { |
04454e1e | 884 | search_bounds(pred.bounds); |
dc9dc135 XL |
885 | } |
886 | } | |
887 | } | |
c295e0f8 XL |
888 | } |
889 | ||
487cf647 | 890 | let sized_def_id = tcx.lang_items().sized_trait(); |
c295e0f8 | 891 | match (&sized_def_id, unbound) { |
487cf647 | 892 | (Some(sized_def_id), Some(tpb)) |
c295e0f8 XL |
893 | if tpb.path.res == Res::Def(DefKind::Trait, *sized_def_id) => |
894 | { | |
895 | // There was in fact a `?Sized` bound, return without doing anything | |
896 | return; | |
dc9dc135 | 897 | } |
c295e0f8 XL |
898 | (_, Some(_)) => { |
899 | // There was a `?Trait` bound, but it was not `?Sized`; warn. | |
900 | tcx.sess.span_warn( | |
901 | span, | |
902 | "default bound relaxed for a type parameter, but \ | |
903 | this does nothing because the given bound is not \ | |
904 | a default; only `?Sized` is supported", | |
905 | ); | |
906 | // Otherwise, add implicitly sized if `Sized` is available. | |
907 | } | |
908 | _ => { | |
909 | // There was no `?Sized` bound; add implicitly sized if `Sized` is available. | |
910 | } | |
911 | } | |
487cf647 | 912 | if sized_def_id.is_none() { |
dc9dc135 | 913 | // No lang item for `Sized`, so we can't add it as a bound. |
c295e0f8 | 914 | return; |
dc9dc135 | 915 | } |
c295e0f8 | 916 | bounds.implicitly_sized = Some(span); |
dc9dc135 XL |
917 | } |
918 | ||
919 | /// This helper takes a *converted* parameter type (`param_ty`) | |
920 | /// and an *unconverted* list of bounds: | |
921 | /// | |
ba9703b0 | 922 | /// ```text |
dc9dc135 XL |
923 | /// fn foo<T: Debug> |
924 | /// ^ ^^^^^ `ast_bounds` parameter, in HIR form | |
925 | /// | | |
926 | /// `param_ty`, in ty form | |
927 | /// ``` | |
928 | /// | |
929 | /// It adds these `ast_bounds` into the `bounds` structure. | |
930 | /// | |
931 | /// **A note on binders:** there is an implied binder around | |
932 | /// `param_ty` and `ast_bounds`. See `instantiate_poly_trait_ref` | |
933 | /// for more details. | |
f2b60f7d | 934 | #[instrument(level = "debug", skip(self, ast_bounds, bounds))] |
c295e0f8 | 935 | pub(crate) fn add_bounds<'hir, I: Iterator<Item = &'hir hir::GenericBound<'hir>>>( |
dfeec247 | 936 | &self, |
dc9dc135 | 937 | param_ty: Ty<'tcx>, |
c295e0f8 | 938 | ast_bounds: I, |
dc9dc135 | 939 | bounds: &mut Bounds<'tcx>, |
cdc7bbd5 | 940 | bound_vars: &'tcx ty::List<ty::BoundVariableKind>, |
dc9dc135 | 941 | ) { |
dc9dc135 | 942 | for ast_bound in ast_bounds { |
c295e0f8 XL |
943 | match ast_bound { |
944 | hir::GenericBound::Trait(poly_trait_ref, modifier) => { | |
945 | let constness = match modifier { | |
946 | hir::TraitBoundModifier::MaybeConst => ty::BoundConstness::ConstIfConst, | |
947 | hir::TraitBoundModifier::None => ty::BoundConstness::NotConst, | |
948 | hir::TraitBoundModifier::Maybe => continue, | |
949 | }; | |
950 | ||
951 | let _ = self.instantiate_poly_trait_ref( | |
952 | &poly_trait_ref.trait_ref, | |
953 | poly_trait_ref.span, | |
954 | constness, | |
cdc7bbd5 XL |
955 | param_ty, |
956 | bounds, | |
957 | false, | |
958 | ); | |
dfeec247 | 959 | } |
c295e0f8 XL |
960 | &hir::GenericBound::LangItemTrait(lang_item, span, hir_id, args) => { |
961 | self.instantiate_lang_item_trait_ref( | |
962 | lang_item, span, hir_id, args, param_ty, bounds, | |
cdc7bbd5 | 963 | ); |
dfeec247 | 964 | } |
c295e0f8 XL |
965 | hir::GenericBound::Outlives(lifetime) => { |
966 | let region = self.ast_region_to_region(lifetime, None); | |
487cf647 FG |
967 | bounds.region_bounds.push(( |
968 | ty::Binder::bind_with_vars(region, bound_vars), | |
969 | lifetime.ident.span, | |
970 | )); | |
c295e0f8 | 971 | } |
dc9dc135 XL |
972 | } |
973 | } | |
dc9dc135 XL |
974 | } |
975 | ||
976 | /// Translates a list of bounds from the HIR into the `Bounds` data structure. | |
977 | /// The self-type for the bounds is given by `param_ty`. | |
978 | /// | |
979 | /// Example: | |
980 | /// | |
04454e1e | 981 | /// ```ignore (illustrative) |
dc9dc135 | 982 | /// fn foo<T: Bar + Baz>() { } |
04454e1e FG |
983 | /// // ^ ^^^^^^^^^ ast_bounds |
984 | /// // param_ty | |
dc9dc135 XL |
985 | /// ``` |
986 | /// | |
987 | /// The `sized_by_default` parameter indicates if, in this context, the `param_ty` should be | |
988 | /// considered `Sized` unless there is an explicit `?Sized` bound. This would be true in the | |
989 | /// example above, but is not true in supertrait listings like `trait Foo: Bar + Baz`. | |
990 | /// | |
991 | /// `span` should be the declaration size of the parameter. | |
c295e0f8 | 992 | pub(crate) fn compute_bounds( |
dfeec247 | 993 | &self, |
dc9dc135 | 994 | param_ty: Ty<'tcx>, |
dfeec247 | 995 | ast_bounds: &[hir::GenericBound<'_>], |
6a06907d | 996 | ) -> Bounds<'tcx> { |
c295e0f8 | 997 | self.compute_bounds_inner(param_ty, ast_bounds) |
6a06907d XL |
998 | } |
999 | ||
1000 | /// Convert the bounds in `ast_bounds` that refer to traits which define an associated type | |
1001 | /// named `assoc_name` into ty::Bounds. Ignore the rest. | |
c295e0f8 | 1002 | pub(crate) fn compute_bounds_that_match_assoc_type( |
6a06907d XL |
1003 | &self, |
1004 | param_ty: Ty<'tcx>, | |
1005 | ast_bounds: &[hir::GenericBound<'_>], | |
6a06907d XL |
1006 | assoc_name: Ident, |
1007 | ) -> Bounds<'tcx> { | |
1008 | let mut result = Vec::new(); | |
1009 | ||
1010 | for ast_bound in ast_bounds { | |
5e7ed085 FG |
1011 | if let Some(trait_ref) = ast_bound.trait_ref() |
1012 | && let Some(trait_did) = trait_ref.trait_def_id() | |
1013 | && self.tcx().trait_may_define_assoc_type(trait_did, assoc_name) | |
1014 | { | |
1015 | result.push(ast_bound.clone()); | |
6a06907d XL |
1016 | } |
1017 | } | |
1018 | ||
c295e0f8 | 1019 | self.compute_bounds_inner(param_ty, &result) |
6a06907d XL |
1020 | } |
1021 | ||
1022 | fn compute_bounds_inner( | |
1023 | &self, | |
1024 | param_ty: Ty<'tcx>, | |
cdc7bbd5 | 1025 | ast_bounds: &[hir::GenericBound<'_>], |
dc9dc135 XL |
1026 | ) -> Bounds<'tcx> { |
1027 | let mut bounds = Bounds::default(); | |
1028 | ||
c295e0f8 | 1029 | self.add_bounds(param_ty, ast_bounds.iter(), &mut bounds, ty::List::empty()); |
04454e1e | 1030 | debug!(?bounds); |
dc9dc135 XL |
1031 | |
1032 | bounds | |
1033 | } | |
1034 | ||
1035 | /// Given an HIR binding like `Item = Foo` or `Item: Foo`, pushes the corresponding predicates | |
1036 | /// onto `bounds`. | |
1037 | /// | |
1038 | /// **A note on binders:** given something like `T: for<'a> Iterator<Item = &'a u32>`, the | |
1039 | /// `trait_ref` here will be `for<'a> T: Iterator`. The `binding` data however is from *inside* | |
1040 | /// the binder (e.g., `&'a u32`) and hence may reference bound regions. | |
f2b60f7d | 1041 | #[instrument(level = "debug", skip(self, bounds, speculative, dup_bindings, path_span))] |
dc9dc135 | 1042 | fn add_predicates_for_ast_type_binding( |
a7813a04 | 1043 | &self, |
532ac7d7 | 1044 | hir_ref_id: hir::HirId, |
9e0c209e | 1045 | trait_ref: ty::PolyTraitRef<'tcx>, |
dc9dc135 XL |
1046 | binding: &ConvertedBinding<'_, 'tcx>, |
1047 | bounds: &mut Bounds<'tcx>, | |
94b46f34 | 1048 | speculative: bool, |
dc9dc135 | 1049 | dup_bindings: &mut FxHashMap<DefId, Span>, |
dfeec247 | 1050 | path_span: Span, |
2b03887a | 1051 | constness: ty::BoundConstness, |
5e7ed085 | 1052 | ) -> Result<(), ErrorGuaranteed> { |
5869c6ff XL |
1053 | // Given something like `U: SomeTrait<T = X>`, we want to produce a |
1054 | // predicate like `<U as SomeTrait>::T = X`. This is somewhat | |
1055 | // subtle in the event that `T` is defined in a supertrait of | |
1056 | // `SomeTrait`, because in that case we need to upcast. | |
1057 | // | |
1058 | // That is, consider this case: | |
1059 | // | |
1060 | // ``` | |
1061 | // trait SubTrait: SuperTrait<i32> { } | |
1062 | // trait SuperTrait<A> { type T; } | |
1063 | // | |
1064 | // ... B: SubTrait<T = foo> ... | |
1065 | // ``` | |
1066 | // | |
1067 | // We want to produce `<B as SuperTrait<i32>>::T == foo`. | |
3dfed10e | 1068 | |
5869c6ff | 1069 | let tcx = self.tcx(); |
a7813a04 | 1070 | |
dfeec247 XL |
1071 | let candidate = |
1072 | if self.trait_defines_associated_type_named(trait_ref.def_id(), binding.item_name) { | |
1073 | // Simple case: X is defined in the current trait. | |
1074 | trait_ref | |
1075 | } else { | |
1076 | // Otherwise, we have to walk through the supertraits to find | |
1077 | // those that do. | |
1078 | self.one_bound_for_assoc_type( | |
1079 | || traits::supertraits(tcx, trait_ref), | |
1080 | || trait_ref.print_only_trait_path().to_string(), | |
1081 | binding.item_name, | |
1082 | path_span, | |
1083 | || match binding.kind { | |
1084 | ConvertedBindingKind::Equality(ty) => Some(ty.to_string()), | |
1085 | _ => None, | |
1086 | }, | |
1087 | )? | |
1088 | }; | |
ff7c6d11 | 1089 | |
94b46f34 | 1090 | let (assoc_ident, def_scope) = |
dc9dc135 | 1091 | tcx.adjust_ident_and_get_scope(binding.item_name, candidate.def_id(), hir_ref_id); |
74b04a01 | 1092 | |
ba9703b0 | 1093 | // We have already adjusted the item name above, so compare with `ident.normalize_to_macros_2_0()` instead |
74b04a01 | 1094 | // of calling `filter_by_name_and_kind`. |
5099ac24 FG |
1095 | let find_item_of_kind = |kind| { |
1096 | tcx.associated_items(candidate.def_id()) | |
1097 | .filter_by_name_unhygienic(assoc_ident.name) | |
1098 | .find(|i| i.kind == kind && i.ident(tcx).normalize_to_macros_2_0() == assoc_ident) | |
1099 | }; | |
1100 | let assoc_item = find_item_of_kind(ty::AssocKind::Type) | |
1101 | .or_else(|| find_item_of_kind(ty::AssocKind::Const)) | |
dfeec247 | 1102 | .expect("missing associated type"); |
ff7c6d11 | 1103 | |
064997fb | 1104 | if !assoc_item.visibility(tcx).is_accessible_from(def_scope, tcx) { |
ba9703b0 XL |
1105 | tcx.sess |
1106 | .struct_span_err( | |
1107 | binding.span, | |
064997fb | 1108 | &format!("{} `{}` is private", assoc_item.kind, binding.item_name), |
ba9703b0 | 1109 | ) |
064997fb | 1110 | .span_label(binding.span, &format!("private {}", assoc_item.kind)) |
ba9703b0 | 1111 | .emit(); |
a7813a04 | 1112 | } |
5099ac24 | 1113 | tcx.check_stability(assoc_item.def_id, Some(hir_ref_id), binding.span, None); |
a7813a04 | 1114 | |
94b46f34 | 1115 | if !speculative { |
dfeec247 | 1116 | dup_bindings |
5099ac24 | 1117 | .entry(assoc_item.def_id) |
94b46f34 | 1118 | .and_modify(|prev_span| { |
1b1a35ee XL |
1119 | self.tcx().sess.emit_err(ValueOfAssociatedStructAlreadySpecified { |
1120 | span: binding.span, | |
1121 | prev_span: *prev_span, | |
1122 | item_name: binding.item_name, | |
064997fb | 1123 | def_path: tcx.def_path_str(assoc_item.container_id(tcx)), |
1b1a35ee | 1124 | }); |
94b46f34 XL |
1125 | }) |
1126 | .or_insert(binding.span); | |
1127 | } | |
1128 | ||
5869c6ff XL |
1129 | // Include substitutions for generic parameters of associated types |
1130 | let projection_ty = candidate.map_bound(|trait_ref| { | |
5099ac24 | 1131 | let ident = Ident::new(assoc_item.name, binding.item_name.span); |
5869c6ff | 1132 | let item_segment = hir::PathSegment { |
17df50a5 | 1133 | ident, |
f2b60f7d FG |
1134 | hir_id: binding.hir_id, |
1135 | res: Res::Err, | |
5869c6ff XL |
1136 | args: Some(binding.gen_args), |
1137 | infer_args: false, | |
1138 | }; | |
1139 | ||
1140 | let substs_trait_ref_and_assoc_item = self.create_substs_for_associated_item( | |
5869c6ff | 1141 | path_span, |
5099ac24 | 1142 | assoc_item.def_id, |
5869c6ff XL |
1143 | &item_segment, |
1144 | trait_ref.substs, | |
1145 | ); | |
1146 | ||
2b03887a | 1147 | debug!(?substs_trait_ref_and_assoc_item); |
5869c6ff XL |
1148 | |
1149 | ty::ProjectionTy { | |
5099ac24 | 1150 | item_def_id: assoc_item.def_id, |
5869c6ff XL |
1151 | substs: substs_trait_ref_and_assoc_item, |
1152 | } | |
1153 | }); | |
1154 | ||
1155 | if !speculative { | |
1156 | // Find any late-bound regions declared in `ty` that are not | |
5099ac24 | 1157 | // declared in the trait-ref or assoc_item. These are not well-formed. |
5869c6ff XL |
1158 | // |
1159 | // Example: | |
1160 | // | |
1161 | // for<'a> <T as Iterator>::Item = &'a str // <-- 'a is bad | |
1162 | // for<'a> <T as FnMut<(&'a u32,)>>::Output = &'a str // <-- 'a is ok | |
1163 | if let ConvertedBindingKind::Equality(ty) = binding.kind { | |
1164 | let late_bound_in_trait_ref = | |
1165 | tcx.collect_constrained_late_bound_regions(&projection_ty); | |
1166 | let late_bound_in_ty = | |
cdc7bbd5 | 1167 | tcx.collect_referenced_late_bound_regions(&trait_ref.rebind(ty)); |
2b03887a FG |
1168 | debug!(?late_bound_in_trait_ref); |
1169 | debug!(?late_bound_in_ty); | |
5869c6ff XL |
1170 | |
1171 | // FIXME: point at the type params that don't have appropriate lifetimes: | |
1172 | // struct S1<F: for<'a> Fn(&i32, &i32) -> &'a i32>(F); | |
1173 | // ---- ---- ^^^^^^^ | |
1174 | self.validate_late_bound_regions( | |
1175 | late_bound_in_trait_ref, | |
1176 | late_bound_in_ty, | |
1177 | |br_name| { | |
1178 | struct_span_err!( | |
1179 | tcx.sess, | |
1180 | binding.span, | |
1181 | E0582, | |
1182 | "binding for associated type `{}` references {}, \ | |
1183 | which does not appear in the trait input types", | |
1184 | binding.item_name, | |
1185 | br_name | |
1186 | ) | |
1187 | }, | |
1188 | ); | |
1189 | } | |
1190 | } | |
1191 | ||
dc9dc135 | 1192 | match binding.kind { |
064997fb | 1193 | ConvertedBindingKind::Equality(mut term) => { |
dc9dc135 XL |
1194 | // "Desugar" a constraint like `T: Iterator<Item = u32>` this to |
1195 | // the "projection predicate" for: | |
1196 | // | |
1197 | // `<T as Iterator>::Item = u32` | |
5099ac24 FG |
1198 | let assoc_item_def_id = projection_ty.skip_binder().item_def_id; |
1199 | let def_kind = tcx.def_kind(assoc_item_def_id); | |
f2b60f7d FG |
1200 | match (def_kind, term.unpack()) { |
1201 | (hir::def::DefKind::AssocTy, ty::TermKind::Ty(_)) | |
1202 | | (hir::def::DefKind::AssocConst, ty::TermKind::Const(_)) => (), | |
5099ac24 | 1203 | (_, _) => { |
f2b60f7d | 1204 | let got = if let Some(_) = term.ty() { "type" } else { "constant" }; |
5099ac24 | 1205 | let expected = def_kind.descr(assoc_item_def_id); |
487cf647 FG |
1206 | let reported = tcx |
1207 | .sess | |
5099ac24 FG |
1208 | .struct_span_err( |
1209 | binding.span, | |
064997fb | 1210 | &format!("expected {expected} bound, found {got}"), |
5099ac24 FG |
1211 | ) |
1212 | .span_note( | |
1213 | tcx.def_span(assoc_item_def_id), | |
064997fb | 1214 | &format!("{expected} defined here"), |
5099ac24 FG |
1215 | ) |
1216 | .emit(); | |
064997fb | 1217 | term = match def_kind { |
487cf647 FG |
1218 | hir::def::DefKind::AssocTy => { |
1219 | tcx.ty_error_with_guaranteed(reported).into() | |
1220 | } | |
064997fb | 1221 | hir::def::DefKind::AssocConst => tcx |
487cf647 | 1222 | .const_error_with_guaranteed( |
064997fb FG |
1223 | tcx.bound_type_of(assoc_item_def_id) |
1224 | .subst(tcx, projection_ty.skip_binder().substs), | |
487cf647 | 1225 | reported, |
064997fb FG |
1226 | ) |
1227 | .into(), | |
1228 | _ => unreachable!(), | |
1229 | }; | |
5099ac24 FG |
1230 | } |
1231 | } | |
dfeec247 | 1232 | bounds.projection_bounds.push(( |
5099ac24 FG |
1233 | projection_ty.map_bound(|projection_ty| ty::ProjectionPredicate { |
1234 | projection_ty, | |
1235 | term: term, | |
dfeec247 XL |
1236 | }), |
1237 | binding.span, | |
1238 | )); | |
9e0c209e | 1239 | } |
dc9dc135 XL |
1240 | ConvertedBindingKind::Constraint(ast_bounds) => { |
1241 | // "Desugar" a constraint like `T: Iterator<Item: Debug>` to | |
1242 | // | |
1243 | // `<T as Iterator>::Item: Debug` | |
1244 | // | |
1245 | // Calling `skip_binder` is okay, because `add_bounds` expects the `param_ty` | |
1246 | // parameter to have a skipped binder. | |
cdc7bbd5 | 1247 | let param_ty = tcx.mk_ty(ty::Projection(projection_ty.skip_binder())); |
c295e0f8 | 1248 | self.add_bounds(param_ty, ast_bounds.iter(), bounds, candidate.bound_vars()); |
dc9dc135 XL |
1249 | } |
1250 | } | |
1251 | Ok(()) | |
1a4d82fc JJ |
1252 | } |
1253 | ||
dfeec247 XL |
1254 | fn ast_path_to_ty( |
1255 | &self, | |
a7813a04 | 1256 | span: Span, |
a7813a04 | 1257 | did: DefId, |
dfeec247 XL |
1258 | item_segment: &hir::PathSegment<'_>, |
1259 | ) -> Ty<'tcx> { | |
32a655c1 | 1260 | let substs = self.ast_path_substs_for_ty(span, did, item_segment); |
04454e1e FG |
1261 | self.normalize_ty( |
1262 | span, | |
1263 | EarlyBinder(self.tcx().at(span).type_of(did)).subst(self.tcx(), substs), | |
1264 | ) | |
1a4d82fc JJ |
1265 | } |
1266 | ||
dfeec247 XL |
1267 | fn conv_object_ty_poly_trait_ref( |
1268 | &self, | |
32a655c1 | 1269 | span: Span, |
dfeec247 XL |
1270 | trait_bounds: &[hir::PolyTraitRef<'_>], |
1271 | lifetime: &hir::Lifetime, | |
3dfed10e | 1272 | borrowed: bool, |
f2b60f7d | 1273 | representation: DynKind, |
dfeec247 | 1274 | ) -> Ty<'tcx> { |
a7813a04 | 1275 | let tcx = self.tcx(); |
9e0c209e | 1276 | |
dc9dc135 XL |
1277 | let mut bounds = Bounds::default(); |
1278 | let mut potential_assoc_types = Vec::new(); | |
532ac7d7 | 1279 | let dummy_self = self.tcx().types.trait_object_dummy_self; |
416331ca | 1280 | for trait_bound in trait_bounds.iter().rev() { |
f9f354fc XL |
1281 | if let GenericArgCountResult { |
1282 | correct: | |
1283 | Err(GenericArgCountMismatch { invalid_args: cur_potential_assoc_types, .. }), | |
1284 | .. | |
1285 | } = self.instantiate_poly_trait_ref( | |
cdc7bbd5 XL |
1286 | &trait_bound.trait_ref, |
1287 | trait_bound.span, | |
94222f64 | 1288 | ty::BoundConstness::NotConst, |
416331ca XL |
1289 | dummy_self, |
1290 | &mut bounds, | |
cdc7bbd5 | 1291 | false, |
74b04a01 | 1292 | ) { |
5869c6ff | 1293 | potential_assoc_types.extend(cur_potential_assoc_types); |
74b04a01 | 1294 | } |
416331ca | 1295 | } |
dc9dc135 XL |
1296 | |
1297 | // Expand trait aliases recursively and check that only one regular (non-auto) trait | |
1298 | // is used and no 'maybe' bounds are used. | |
74b04a01 XL |
1299 | let expanded_traits = |
1300 | traits::expand_trait_aliases(tcx, bounds.trait_bounds.iter().map(|&(a, b, _)| (a, b))); | |
04454e1e FG |
1301 | let (mut auto_traits, regular_traits): (Vec<_>, Vec<_>) = expanded_traits |
1302 | .filter(|i| i.trait_ref().self_ty().skip_binder() == dummy_self) | |
1303 | .partition(|i| tcx.trait_is_auto(i.trait_ref().def_id())); | |
dc9dc135 XL |
1304 | if regular_traits.len() > 1 { |
1305 | let first_trait = ®ular_traits[0]; | |
1306 | let additional_trait = ®ular_traits[1]; | |
dfeec247 XL |
1307 | let mut err = struct_span_err!( |
1308 | tcx.sess, | |
1309 | additional_trait.bottom().1, | |
1310 | E0225, | |
dc9dc135 XL |
1311 | "only auto traits can be used as additional traits in a trait object" |
1312 | ); | |
dfeec247 XL |
1313 | additional_trait.label_with_exp_info( |
1314 | &mut err, | |
1315 | "additional non-auto trait", | |
1316 | "additional use", | |
1317 | ); | |
1318 | first_trait.label_with_exp_info(&mut err, "first non-auto trait", "first use"); | |
3dfed10e | 1319 | err.help(&format!( |
c295e0f8 | 1320 | "consider creating a new trait with all of these as supertraits and using that \ |
3dfed10e XL |
1321 | trait here instead: `trait NewTrait: {} {{}}`", |
1322 | regular_traits | |
1323 | .iter() | |
1324 | .map(|t| t.trait_ref().print_only_trait_path().to_string()) | |
1325 | .collect::<Vec<_>>() | |
1326 | .join(" + "), | |
1327 | )); | |
1328 | err.note( | |
1329 | "auto-traits like `Send` and `Sync` are traits that have special properties; \ | |
1330 | for more information on them, visit \ | |
1331 | <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits>", | |
1332 | ); | |
dc9dc135 | 1333 | err.emit(); |
7cac9316 XL |
1334 | } |
1335 | ||
dc9dc135 | 1336 | if regular_traits.is_empty() && auto_traits.is_empty() { |
04454e1e FG |
1337 | let trait_alias_span = bounds |
1338 | .trait_bounds | |
1339 | .iter() | |
1340 | .map(|&(trait_ref, _, _)| trait_ref.def_id()) | |
1341 | .find(|&trait_ref| tcx.is_trait_alias(trait_ref)) | |
1342 | .map(|trait_ref| tcx.def_span(trait_ref)); | |
487cf647 FG |
1343 | let reported = |
1344 | tcx.sess.emit_err(TraitObjectDeclaredWithNoTraits { span, trait_alias_span }); | |
1345 | return tcx.ty_error_with_guaranteed(reported); | |
9e0c209e SL |
1346 | } |
1347 | ||
a1dfa0c6 XL |
1348 | // Check that there are no gross object safety violations; |
1349 | // most importantly, that the supertraits don't contain `Self`, | |
1350 | // to avoid ICEs. | |
dc9dc135 XL |
1351 | for item in ®ular_traits { |
1352 | let object_safety_violations = | |
dfeec247 | 1353 | astconv_object_safety_violations(tcx, item.trait_ref().def_id()); |
dc9dc135 | 1354 | if !object_safety_violations.is_empty() { |
487cf647 | 1355 | let reported = report_object_safety_error( |
dfeec247 | 1356 | tcx, |
dc9dc135 XL |
1357 | span, |
1358 | item.trait_ref().def_id(), | |
a2a8927a | 1359 | &object_safety_violations, |
dfeec247 XL |
1360 | ) |
1361 | .emit(); | |
487cf647 | 1362 | return tcx.ty_error_with_guaranteed(reported); |
dc9dc135 | 1363 | } |
a7813a04 XL |
1364 | } |
1365 | ||
a1dfa0c6 | 1366 | // Use a `BTreeSet` to keep output in a more consistent order. |
dfeec247 | 1367 | let mut associated_types: FxHashMap<Span, BTreeSet<DefId>> = FxHashMap::default(); |
b7449926 | 1368 | |
dfeec247 XL |
1369 | let regular_traits_refs_spans = bounds |
1370 | .trait_bounds | |
dc9dc135 | 1371 | .into_iter() |
dfeec247 | 1372 | .filter(|(trait_ref, _, _)| !tcx.trait_is_auto(trait_ref.def_id())); |
a7813a04 | 1373 | |
dfeec247 | 1374 | for (base_trait_ref, span, constness) in regular_traits_refs_spans { |
94222f64 | 1375 | assert_eq!(constness, ty::BoundConstness::NotConst); |
a7813a04 | 1376 | |
ba9703b0 | 1377 | for obligation in traits::elaborate_trait_ref(tcx, base_trait_ref) { |
dfeec247 XL |
1378 | debug!( |
1379 | "conv_object_ty_poly_trait_ref: observing object predicate `{:?}`", | |
ba9703b0 | 1380 | obligation.predicate |
a1dfa0c6 | 1381 | ); |
3dfed10e | 1382 | |
5869c6ff | 1383 | let bound_predicate = obligation.predicate.kind(); |
29967ef6 | 1384 | match bound_predicate.skip_binder() { |
487cf647 | 1385 | ty::PredicateKind::Clause(ty::Clause::Trait(pred)) => { |
29967ef6 | 1386 | let pred = bound_predicate.rebind(pred); |
dfeec247 XL |
1387 | associated_types.entry(span).or_default().extend( |
1388 | tcx.associated_items(pred.def_id()) | |
74b04a01 | 1389 | .in_definition_order() |
dfeec247 XL |
1390 | .filter(|item| item.kind == ty::AssocKind::Type) |
1391 | .map(|item| item.def_id), | |
1392 | ); | |
1393 | } | |
487cf647 | 1394 | ty::PredicateKind::Clause(ty::Clause::Projection(pred)) => { |
29967ef6 | 1395 | let pred = bound_predicate.rebind(pred); |
dfeec247 XL |
1396 | // A `Self` within the original bound will be substituted with a |
1397 | // `trait_object_dummy_self`, so check for that. | |
f2b60f7d FG |
1398 | let references_self = match pred.skip_binder().term.unpack() { |
1399 | ty::TermKind::Ty(ty) => ty.walk().any(|arg| arg == dummy_self.into()), | |
1400 | ty::TermKind::Const(c) => { | |
1401 | c.ty().walk().any(|arg| arg == dummy_self.into()) | |
1402 | } | |
5099ac24 | 1403 | }; |
dfeec247 XL |
1404 | |
1405 | // If the projection output contains `Self`, force the user to | |
1406 | // elaborate it explicitly to avoid a lot of complexity. | |
1407 | // | |
5e7ed085 | 1408 | // The "classically useful" case is the following: |
dfeec247 XL |
1409 | // ``` |
1410 | // trait MyTrait: FnMut() -> <Self as MyTrait>::MyOutput { | |
1411 | // type MyOutput; | |
1412 | // } | |
1413 | // ``` | |
1414 | // | |
1415 | // Here, the user could theoretically write `dyn MyTrait<Output = X>`, | |
1416 | // but actually supporting that would "expand" to an infinitely-long type | |
1417 | // `fix $ τ → dyn MyTrait<MyOutput = X, Output = <τ as MyTrait>::MyOutput`. | |
1418 | // | |
1419 | // Instead, we force the user to write | |
1420 | // `dyn MyTrait<MyOutput = X, Output = X>`, which is uglier but works. See | |
1421 | // the discussion in #56288 for alternatives. | |
1422 | if !references_self { | |
1423 | // Include projections defined on supertraits. | |
1424 | bounds.projection_bounds.push((pred, span)); | |
1425 | } | |
a1dfa0c6 | 1426 | } |
dfeec247 | 1427 | _ => (), |
a1dfa0c6 XL |
1428 | } |
1429 | } | |
dfeec247 XL |
1430 | } |
1431 | ||
1432 | for (projection_bound, _) in &bounds.projection_bounds { | |
74b04a01 | 1433 | for def_ids in associated_types.values_mut() { |
dfeec247 | 1434 | def_ids.remove(&projection_bound.projection_def_id()); |
a1dfa0c6 | 1435 | } |
a7813a04 | 1436 | } |
9346a6ac | 1437 | |
dfeec247 XL |
1438 | self.complain_about_missing_associated_types( |
1439 | associated_types, | |
1440 | potential_assoc_types, | |
1441 | trait_bounds, | |
1442 | ); | |
1443 | ||
dc9dc135 XL |
1444 | // De-duplicate auto traits so that, e.g., `dyn Trait + Send + Send` is the same as |
1445 | // `dyn Trait + Send`. | |
6a06907d XL |
1446 | // We remove duplicates by inserting into a `FxHashSet` to avoid re-ordering |
1447 | // the bounds | |
1448 | let mut duplicates = FxHashSet::default(); | |
1449 | auto_traits.retain(|i| duplicates.insert(i.trait_ref().def_id())); | |
dc9dc135 XL |
1450 | debug!("regular_traits: {:?}", regular_traits); |
1451 | debug!("auto_traits: {:?}", auto_traits); | |
1452 | ||
532ac7d7 | 1453 | // Erase the `dummy_self` (`trait_object_dummy_self`) used above. |
6a06907d XL |
1454 | let existential_trait_refs = regular_traits.iter().map(|i| { |
1455 | i.trait_ref().map_bound(|trait_ref: ty::TraitRef<'tcx>| { | |
f2b60f7d FG |
1456 | assert_eq!(trait_ref.self_ty(), dummy_self); |
1457 | ||
1458 | // Verify that `dummy_self` did not leak inside default type parameters. This | |
1459 | // could not be done at path creation, since we need to see through trait aliases. | |
1460 | let mut missing_type_params = vec![]; | |
1461 | let mut references_self = false; | |
1462 | let generics = tcx.generics_of(trait_ref.def_id); | |
1463 | let substs: Vec<_> = trait_ref | |
1464 | .substs | |
1465 | .iter() | |
1466 | .enumerate() | |
1467 | .skip(1) // Remove `Self` for `ExistentialPredicate`. | |
1468 | .map(|(index, arg)| { | |
1469 | if arg == dummy_self.into() { | |
1470 | let param = &generics.params[index]; | |
1471 | missing_type_params.push(param.name); | |
1472 | return tcx.ty_error().into(); | |
1473 | } else if arg.walk().any(|arg| arg == dummy_self.into()) { | |
1474 | references_self = true; | |
1475 | return tcx.ty_error().into(); | |
1476 | } | |
1477 | arg | |
1478 | }) | |
1479 | .collect(); | |
1480 | let substs = tcx.intern_substs(&substs[..]); | |
1481 | ||
1482 | let span = i.bottom().1; | |
1483 | let empty_generic_args = trait_bounds.iter().any(|hir_bound| { | |
1484 | hir_bound.trait_ref.path.res == Res::Def(DefKind::Trait, trait_ref.def_id) | |
1485 | && hir_bound.span.contains(span) | |
1486 | }); | |
1487 | self.complain_about_missing_type_params( | |
1488 | missing_type_params, | |
1489 | trait_ref.def_id, | |
1490 | span, | |
1491 | empty_generic_args, | |
1492 | ); | |
1493 | ||
1494 | if references_self { | |
1495 | let def_id = i.bottom().0.def_id(); | |
1496 | let mut err = struct_span_err!( | |
1497 | tcx.sess, | |
1498 | i.bottom().1, | |
1499 | E0038, | |
1500 | "the {} `{}` cannot be made into an object", | |
1501 | tcx.def_kind(def_id).descr(def_id), | |
1502 | tcx.item_name(def_id), | |
1503 | ); | |
1504 | err.note( | |
1505 | rustc_middle::traits::ObjectSafetyViolation::SupertraitSelf(smallvec![]) | |
1506 | .error_msg(), | |
6a06907d | 1507 | ); |
f2b60f7d | 1508 | err.emit(); |
6a06907d | 1509 | } |
f2b60f7d FG |
1510 | |
1511 | ty::ExistentialTraitRef { def_id: trait_ref.def_id, substs } | |
6a06907d XL |
1512 | }) |
1513 | }); | |
f2b60f7d | 1514 | |
dc9dc135 | 1515 | let existential_projections = bounds.projection_bounds.iter().map(|(bound, _)| { |
f2b60f7d FG |
1516 | bound.map_bound(|mut b| { |
1517 | assert_eq!(b.projection_ty.self_ty(), dummy_self); | |
1518 | ||
1519 | // Like for trait refs, verify that `dummy_self` did not leak inside default type | |
1520 | // parameters. | |
1521 | let references_self = b.projection_ty.substs.iter().skip(1).any(|arg| { | |
1522 | if arg.walk().any(|arg| arg == dummy_self.into()) { | |
1523 | return true; | |
1524 | } | |
1525 | false | |
1526 | }); | |
1527 | if references_self { | |
1528 | tcx.sess | |
1529 | .delay_span_bug(span, "trait object projection bounds reference `Self`"); | |
1530 | let substs: Vec<_> = b | |
1531 | .projection_ty | |
1532 | .substs | |
1533 | .iter() | |
1534 | .map(|arg| { | |
1535 | if arg.walk().any(|arg| arg == dummy_self.into()) { | |
1536 | return tcx.ty_error().into(); | |
1537 | } | |
1538 | arg | |
1539 | }) | |
1540 | .collect(); | |
1541 | b.projection_ty.substs = tcx.intern_substs(&substs[..]); | |
a1dfa0c6 | 1542 | } |
f2b60f7d | 1543 | |
6a06907d | 1544 | ty::ExistentialProjection::erase_self_ty(tcx, b) |
a1dfa0c6 XL |
1545 | }) |
1546 | }); | |
1547 | ||
5869c6ff XL |
1548 | let regular_trait_predicates = existential_trait_refs |
1549 | .map(|trait_ref| trait_ref.map_bound(ty::ExistentialPredicate::Trait)); | |
fc512014 XL |
1550 | let auto_trait_predicates = auto_traits.into_iter().map(|trait_ref| { |
1551 | ty::Binder::dummy(ty::ExistentialPredicate::AutoTrait(trait_ref.trait_ref().def_id())) | |
1552 | }); | |
17df50a5 XL |
1553 | // N.b. principal, projections, auto traits |
1554 | // FIXME: This is actually wrong with multiple principals in regards to symbol mangling | |
dfeec247 | 1555 | let mut v = regular_trait_predicates |
dfeec247 | 1556 | .chain( |
5869c6ff | 1557 | existential_projections.map(|x| x.map_bound(ty::ExistentialPredicate::Projection)), |
dfeec247 | 1558 | ) |
17df50a5 | 1559 | .chain(auto_trait_predicates) |
b7449926 | 1560 | .collect::<SmallVec<[_; 8]>>(); |
fc512014 | 1561 | v.sort_by(|a, b| a.skip_binder().stable_cmp(tcx, &b.skip_binder())); |
0731742a | 1562 | v.dedup(); |
fc512014 | 1563 | let existential_predicates = tcx.mk_poly_existential_predicates(v.into_iter()); |
476ff2be | 1564 | |
a1dfa0c6 | 1565 | // Use explicitly-specified region bound. |
32a655c1 SL |
1566 | let region_bound = if !lifetime.is_elided() { |
1567 | self.ast_region_to_region(lifetime, None) | |
1568 | } else { | |
1569 | self.compute_object_lifetime_bound(span, existential_predicates).unwrap_or_else(|| { | |
9fa01778 | 1570 | if tcx.named_region(lifetime.hir_id).is_some() { |
32a655c1 SL |
1571 | self.ast_region_to_region(lifetime, None) |
1572 | } else { | |
dc9dc135 | 1573 | self.re_infer(None, span).unwrap_or_else(|| { |
3dfed10e | 1574 | let mut err = struct_span_err!( |
dfeec247 XL |
1575 | tcx.sess, |
1576 | span, | |
1577 | E0228, | |
dc9dc135 | 1578 | "the lifetime bound for this object type cannot be deduced \ |
dfeec247 | 1579 | from context; please supply an explicit bound" |
3dfed10e XL |
1580 | ); |
1581 | if borrowed { | |
1582 | // We will have already emitted an error E0106 complaining about a | |
1583 | // missing named lifetime in `&dyn Trait`, so we elide this one. | |
1584 | err.delay_as_bug(); | |
1585 | } else { | |
1586 | err.emit(); | |
1587 | } | |
48663c56 | 1588 | tcx.lifetimes.re_static |
32a655c1 SL |
1589 | }) |
1590 | } | |
1591 | }) | |
476ff2be | 1592 | }; |
476ff2be SL |
1593 | debug!("region_bound: {:?}", region_bound); |
1594 | ||
f2b60f7d | 1595 | let ty = tcx.mk_dynamic(existential_predicates, region_bound, representation); |
9e0c209e SL |
1596 | debug!("trait_object_type: {:?}", ty); |
1597 | ty | |
9346a6ac AL |
1598 | } |
1599 | ||
48663c56 XL |
1600 | fn report_ambiguous_associated_type( |
1601 | &self, | |
1602 | span: Span, | |
1603 | type_str: &str, | |
1604 | trait_str: &str, | |
f9f354fc | 1605 | name: Symbol, |
5e7ed085 | 1606 | ) -> ErrorGuaranteed { |
48663c56 | 1607 | let mut err = struct_span_err!(self.tcx().sess, span, E0223, "ambiguous associated type"); |
923072b8 FG |
1608 | if self |
1609 | .tcx() | |
1610 | .resolutions(()) | |
1611 | .confused_type_with_std_module | |
1612 | .keys() | |
1613 | .any(|full_span| full_span.contains(span)) | |
1614 | { | |
48663c56 | 1615 | err.span_suggestion( |
923072b8 | 1616 | span.shrink_to_lo(), |
48663c56 | 1617 | "you are looking for the module in `std`, not the primitive type", |
923072b8 | 1618 | "std::", |
48663c56 XL |
1619 | Applicability::MachineApplicable, |
1620 | ); | |
1621 | } else { | |
1622 | err.span_suggestion( | |
dfeec247 XL |
1623 | span, |
1624 | "use fully-qualified syntax", | |
1625 | format!("<{} as {}>::{}", type_str, trait_str, name), | |
1626 | Applicability::HasPlaceholders, | |
48663c56 XL |
1627 | ); |
1628 | } | |
5e7ed085 | 1629 | err.emit() |
a7813a04 | 1630 | } |
9346a6ac | 1631 | |
a7813a04 | 1632 | // Search for a bound on a type parameter which includes the associated item |
dc9dc135 | 1633 | // given by `assoc_name`. `ty_param_def_id` is the `DefId` of the type parameter |
8bb4bdeb | 1634 | // This function will fail if there are no suitable bounds or there is |
a7813a04 | 1635 | // any ambiguity. |
dfeec247 XL |
1636 | fn find_bound_for_assoc_item( |
1637 | &self, | |
f9f354fc XL |
1638 | ty_param_def_id: LocalDefId, |
1639 | assoc_name: Ident, | |
dfeec247 | 1640 | span: Span, |
5e7ed085 | 1641 | ) -> Result<ty::PolyTraitRef<'tcx>, ErrorGuaranteed> { |
a7813a04 | 1642 | let tcx = self.tcx(); |
c34b1796 | 1643 | |
416331ca XL |
1644 | debug!( |
1645 | "find_bound_for_assoc_item(ty_param_def_id={:?}, assoc_name={:?}, span={:?})", | |
dfeec247 | 1646 | ty_param_def_id, assoc_name, span, |
416331ca XL |
1647 | ); |
1648 | ||
6a06907d XL |
1649 | let predicates = &self |
1650 | .get_type_parameter_bounds(span, ty_param_def_id.to_def_id(), assoc_name) | |
1651 | .predicates; | |
416331ca XL |
1652 | |
1653 | debug!("find_bound_for_assoc_item: predicates={:#?}", predicates); | |
1654 | ||
04454e1e | 1655 | let param_name = tcx.hir().ty_param_name(ty_param_def_id); |
dfeec247 XL |
1656 | self.one_bound_for_assoc_type( |
1657 | || { | |
6a06907d | 1658 | traits::transitive_bounds_that_define_assoc_type( |
dfeec247 | 1659 | tcx, |
fc512014 | 1660 | predicates.iter().filter_map(|(p, _)| { |
a2a8927a | 1661 | Some(p.to_opt_poly_trait_pred()?.map_bound(|t| t.trait_ref)) |
fc512014 | 1662 | }), |
6a06907d | 1663 | assoc_name, |
dfeec247 XL |
1664 | ) |
1665 | }, | |
1666 | || param_name.to_string(), | |
1667 | assoc_name, | |
1668 | span, | |
1669 | || None, | |
1670 | ) | |
9346a6ac AL |
1671 | } |
1672 | ||
a1dfa0c6 | 1673 | // Checks that `bounds` contains exactly one element and reports appropriate |
a7813a04 | 1674 | // errors otherwise. |
2b03887a | 1675 | #[instrument(level = "debug", skip(self, all_candidates, ty_param_name, is_equality), ret)] |
dfeec247 XL |
1676 | fn one_bound_for_assoc_type<I>( |
1677 | &self, | |
1678 | all_candidates: impl Fn() -> I, | |
1679 | ty_param_name: impl Fn() -> String, | |
f9f354fc | 1680 | assoc_name: Ident, |
dfeec247 XL |
1681 | span: Span, |
1682 | is_equality: impl Fn() -> Option<String>, | |
5e7ed085 | 1683 | ) -> Result<ty::PolyTraitRef<'tcx>, ErrorGuaranteed> |
dfeec247 XL |
1684 | where |
1685 | I: Iterator<Item = ty::PolyTraitRef<'tcx>>, | |
a7813a04 | 1686 | { |
dfeec247 XL |
1687 | let mut matching_candidates = all_candidates() |
1688 | .filter(|r| self.trait_defines_associated_type_named(r.def_id(), assoc_name)); | |
5099ac24 FG |
1689 | let mut const_candidates = all_candidates() |
1690 | .filter(|r| self.trait_defines_associated_const_named(r.def_id(), assoc_name)); | |
dfeec247 | 1691 | |
5099ac24 FG |
1692 | let (bound, next_cand) = match (matching_candidates.next(), const_candidates.next()) { |
1693 | (Some(bound), _) => (bound, matching_candidates.next()), | |
1694 | (None, Some(bound)) => (bound, const_candidates.next()), | |
1695 | (None, None) => { | |
5e7ed085 | 1696 | let reported = self.complain_about_assoc_type_not_found( |
dfeec247 XL |
1697 | all_candidates, |
1698 | &ty_param_name(), | |
1699 | assoc_name, | |
1700 | span, | |
1701 | ); | |
5e7ed085 | 1702 | return Err(reported); |
476ff2be SL |
1703 | } |
1704 | }; | |
2b03887a | 1705 | debug!(?bound); |
416331ca | 1706 | |
5099ac24 | 1707 | if let Some(bound2) = next_cand { |
2b03887a | 1708 | debug!(?bound2); |
416331ca | 1709 | |
dfeec247 | 1710 | let is_equality = is_equality(); |
a2a8927a | 1711 | let bounds = IntoIterator::into_iter([bound, bound2]).chain(matching_candidates); |
dfeec247 XL |
1712 | let mut err = if is_equality.is_some() { |
1713 | // More specific Error Index entry. | |
1714 | struct_span_err!( | |
1715 | self.tcx().sess, | |
1716 | span, | |
1717 | E0222, | |
1718 | "ambiguous associated type `{}` in bounds of `{}`", | |
1719 | assoc_name, | |
1720 | ty_param_name() | |
1721 | ) | |
1722 | } else { | |
1723 | struct_span_err!( | |
1724 | self.tcx().sess, | |
1725 | span, | |
1726 | E0221, | |
1727 | "ambiguous associated type `{}` in bounds of `{}`", | |
1728 | assoc_name, | |
1729 | ty_param_name() | |
1730 | ) | |
1731 | }; | |
7cac9316 | 1732 | err.span_label(span, format!("ambiguous associated type `{}`", assoc_name)); |
9346a6ac | 1733 | |
dfeec247 | 1734 | let mut where_bounds = vec![]; |
476ff2be | 1735 | for bound in bounds { |
74b04a01 | 1736 | let bound_id = bound.def_id(); |
dfeec247 XL |
1737 | let bound_span = self |
1738 | .tcx() | |
74b04a01 XL |
1739 | .associated_items(bound_id) |
1740 | .find_by_name_and_kind(self.tcx(), assoc_name, ty::AssocKind::Type, bound_id) | |
416331ca | 1741 | .and_then(|item| self.tcx().hir().span_if_local(item.def_id)); |
476ff2be | 1742 | |
dfeec247 XL |
1743 | if let Some(bound_span) = bound_span { |
1744 | err.span_label( | |
1745 | bound_span, | |
1746 | format!( | |
1747 | "ambiguous `{}` from `{}`", | |
1748 | assoc_name, | |
1749 | bound.print_only_trait_path(), | |
1750 | ), | |
1751 | ); | |
1752 | if let Some(constraint) = &is_equality { | |
1753 | where_bounds.push(format!( | |
1754 | " T: {trait}::{assoc} = {constraint}", | |
1755 | trait=bound.print_only_trait_path(), | |
1756 | assoc=assoc_name, | |
1757 | constraint=constraint, | |
1758 | )); | |
1759 | } else { | |
c295e0f8 XL |
1760 | err.span_suggestion_verbose( |
1761 | span.with_hi(assoc_name.span.lo()), | |
dfeec247 XL |
1762 | "use fully qualified syntax to disambiguate", |
1763 | format!( | |
c295e0f8 | 1764 | "<{} as {}>::", |
dfeec247 XL |
1765 | ty_param_name(), |
1766 | bound.print_only_trait_path(), | |
dfeec247 XL |
1767 | ), |
1768 | Applicability::MaybeIncorrect, | |
1769 | ); | |
1770 | } | |
c30ab7b3 | 1771 | } else { |
dfeec247 XL |
1772 | err.note(&format!( |
1773 | "associated type `{}` could derive from `{}`", | |
1774 | ty_param_name(), | |
1775 | bound.print_only_trait_path(), | |
1776 | )); | |
c30ab7b3 | 1777 | } |
a7813a04 | 1778 | } |
dfeec247 XL |
1779 | if !where_bounds.is_empty() { |
1780 | err.help(&format!( | |
1781 | "consider introducing a new type parameter `T` and adding `where` constraints:\ | |
1782 | \n where\n T: {},\n{}", | |
1783 | ty_param_name(), | |
1784 | where_bounds.join(",\n"), | |
1785 | )); | |
1786 | } | |
5e7ed085 | 1787 | let reported = err.emit(); |
dfeec247 | 1788 | if !where_bounds.is_empty() { |
5e7ed085 | 1789 | return Err(reported); |
dfeec247 | 1790 | } |
9346a6ac | 1791 | } |
5099ac24 | 1792 | |
ba9703b0 | 1793 | Ok(bound) |
9346a6ac AL |
1794 | } |
1795 | ||
a7813a04 | 1796 | // Create a type from a path to an associated type. |
9fa01778 | 1797 | // For a path `A::B::C::D`, `qself_ty` and `qself_def` are the type and def for `A::B::C` |
a1dfa0c6 | 1798 | // and item_segment is the path segment for `D`. We return a type and a def for |
a7813a04 | 1799 | // the whole path. |
9fa01778 | 1800 | // Will fail except for `T::A` and `Self::A`; i.e., if `qself_ty`/`qself_def` are not a type |
a1dfa0c6 | 1801 | // parameter or `Self`. |
6a06907d | 1802 | // NOTE: When this function starts resolving `Trait::AssocTy` successfully |
5e7ed085 | 1803 | // it should also start reporting the `BARE_TRAIT_OBJECTS` lint. |
2b03887a | 1804 | #[instrument(level = "debug", skip(self, hir_ref_id, span, qself, assoc_segment), fields(assoc_ident=?assoc_segment.ident), ret)] |
9fa01778 XL |
1805 | pub fn associated_path_to_ty( |
1806 | &self, | |
532ac7d7 | 1807 | hir_ref_id: hir::HirId, |
9fa01778 XL |
1808 | span: Span, |
1809 | qself_ty: Ty<'tcx>, | |
923072b8 | 1810 | qself: &hir::Ty<'_>, |
dfeec247 | 1811 | assoc_segment: &hir::PathSegment<'_>, |
9fa01778 | 1812 | permit_variants: bool, |
5e7ed085 | 1813 | ) -> Result<(Ty<'tcx>, DefKind, DefId), ErrorGuaranteed> { |
a7813a04 | 1814 | let tcx = self.tcx(); |
9fa01778 | 1815 | let assoc_ident = assoc_segment.ident; |
923072b8 FG |
1816 | let qself_res = if let hir::TyKind::Path(hir::QPath::Resolved(_, ref path)) = qself.kind { |
1817 | path.res | |
1818 | } else { | |
1819 | Res::Err | |
1820 | }; | |
a7813a04 | 1821 | |
9fa01778 XL |
1822 | // Check if we have an enum variant. |
1823 | let mut variant_resolution = None; | |
487cf647 | 1824 | if let ty::Adt(adt_def, adt_substs) = qself_ty.kind() { |
9fa01778 | 1825 | if adt_def.is_enum() { |
dfeec247 | 1826 | let variant_def = adt_def |
5e7ed085 | 1827 | .variants() |
dfeec247 | 1828 | .iter() |
5e7ed085 | 1829 | .find(|vd| tcx.hygienic_eq(assoc_ident, vd.ident(tcx), adt_def.did())); |
9fa01778 | 1830 | if let Some(variant_def) = variant_def { |
9fa01778 | 1831 | if permit_variants { |
17df50a5 | 1832 | tcx.check_stability(variant_def.def_id, Some(hir_ref_id), span, None); |
923072b8 FG |
1833 | self.prohibit_generics(slice::from_ref(assoc_segment).iter(), |err| { |
1834 | err.note("enum variants can't have type parameters"); | |
1835 | let type_name = tcx.item_name(adt_def.did()); | |
1836 | let msg = format!( | |
1837 | "you might have meant to specity type parameters on enum \ | |
1838 | `{type_name}`" | |
1839 | ); | |
1840 | let Some(args) = assoc_segment.args else { return; }; | |
1841 | // Get the span of the generics args *including* the leading `::`. | |
1842 | let args_span = assoc_segment.ident.span.shrink_to_hi().to(args.span_ext); | |
1843 | if tcx.generics_of(adt_def.did()).count() == 0 { | |
1844 | // FIXME(estebank): we could also verify that the arguments being | |
1845 | // work for the `enum`, instead of just looking if it takes *any*. | |
1846 | err.span_suggestion_verbose( | |
1847 | args_span, | |
1848 | &format!("{type_name} doesn't have generic parameters"), | |
1849 | "", | |
1850 | Applicability::MachineApplicable, | |
1851 | ); | |
1852 | return; | |
1853 | } | |
1854 | let Ok(snippet) = tcx.sess.source_map().span_to_snippet(args_span) else { | |
1855 | err.note(&msg); | |
1856 | return; | |
1857 | }; | |
1858 | let (qself_sugg_span, is_self) = if let hir::TyKind::Path( | |
1859 | hir::QPath::Resolved(_, ref path) | |
1860 | ) = qself.kind { | |
1861 | // If the path segment already has type params, we want to overwrite | |
1862 | // them. | |
1863 | match &path.segments[..] { | |
1864 | // `segment` is the previous to last element on the path, | |
1865 | // which would normally be the `enum` itself, while the last | |
1866 | // `_` `PathSegment` corresponds to the variant. | |
1867 | [.., hir::PathSegment { | |
1868 | ident, | |
1869 | args, | |
f2b60f7d | 1870 | res: Res::Def(DefKind::Enum, _), |
923072b8 FG |
1871 | .. |
1872 | }, _] => ( | |
1873 | // We need to include the `::` in `Type::Variant::<Args>` | |
1874 | // to point the span to `::<Args>`, not just `<Args>`. | |
1875 | ident.span.shrink_to_hi().to(args.map_or( | |
1876 | ident.span.shrink_to_hi(), | |
1877 | |a| a.span_ext)), | |
1878 | false, | |
1879 | ), | |
1880 | [segment] => ( | |
1881 | // We need to include the `::` in `Type::Variant::<Args>` | |
1882 | // to point the span to `::<Args>`, not just `<Args>`. | |
1883 | segment.ident.span.shrink_to_hi().to(segment.args.map_or( | |
1884 | segment.ident.span.shrink_to_hi(), | |
1885 | |a| a.span_ext)), | |
1886 | kw::SelfUpper == segment.ident.name, | |
1887 | ), | |
1888 | _ => { | |
1889 | err.note(&msg); | |
1890 | return; | |
1891 | } | |
1892 | } | |
1893 | } else { | |
1894 | err.note(&msg); | |
1895 | return; | |
1896 | }; | |
1897 | let suggestion = vec![ | |
1898 | if is_self { | |
1899 | // Account for people writing `Self::Variant::<Args>`, where | |
1900 | // `Self` is the enum, and suggest replacing `Self` with the | |
1901 | // appropriate type: `Type::<Args>::Variant`. | |
1902 | (qself.span, format!("{type_name}{snippet}")) | |
1903 | } else { | |
1904 | (qself_sugg_span, snippet) | |
1905 | }, | |
1906 | (args_span, String::new()), | |
1907 | ]; | |
1908 | err.multipart_suggestion_verbose( | |
1909 | &msg, | |
1910 | suggestion, | |
1911 | Applicability::MaybeIncorrect, | |
1912 | ); | |
1913 | }); | |
48663c56 | 1914 | return Ok((qself_ty, DefKind::Variant, variant_def.def_id)); |
9fa01778 | 1915 | } else { |
48663c56 | 1916 | variant_resolution = Some(variant_def.def_id); |
9fa01778 XL |
1917 | } |
1918 | } | |
1919 | } | |
487cf647 FG |
1920 | |
1921 | // see if we can satisfy using an inherent associated type | |
1922 | for &impl_ in tcx.inherent_impls(adt_def.did()) { | |
1923 | let Some(assoc_ty_did) = self.lookup_assoc_ty(assoc_ident, hir_ref_id, span, impl_) else { | |
1924 | continue; | |
1925 | }; | |
1926 | let item_substs = self.create_substs_for_associated_item( | |
1927 | span, | |
1928 | assoc_ty_did, | |
1929 | assoc_segment, | |
1930 | adt_substs, | |
1931 | ); | |
1932 | let ty = tcx.bound_type_of(assoc_ty_did).subst(tcx, item_substs); | |
1933 | let ty = self.normalize_ty(span, ty); | |
1934 | return Ok((ty, DefKind::AssocTy, assoc_ty_did)); | |
1935 | } | |
9fa01778 | 1936 | } |
a7813a04 XL |
1937 | |
1938 | // Find the type of the associated item, and the trait where the associated | |
1939 | // item is declared. | |
1b1a35ee | 1940 | let bound = match (&qself_ty.kind(), qself_res) { |
2b03887a | 1941 | (_, Res::SelfTyAlias { alias_to: impl_def_id, is_trait_impl: true, .. }) => { |
0731742a | 1942 | // `Self` in an impl of a trait -- we have a concrete self type and a |
a7813a04 | 1943 | // trait reference. |
5e7ed085 FG |
1944 | let Some(trait_ref) = tcx.impl_trait_ref(impl_def_id) else { |
1945 | // A cycle error occurred, most likely. | |
1946 | let guar = tcx.sess.delay_span_bug(span, "expected cycle error"); | |
1947 | return Err(guar); | |
8bb4bdeb XL |
1948 | }; |
1949 | ||
dfeec247 | 1950 | self.one_bound_for_assoc_type( |
136023e0 | 1951 | || traits::supertraits(tcx, ty::Binder::dummy(trait_ref)), |
dfeec247 XL |
1952 | || "Self".to_string(), |
1953 | assoc_ident, | |
1954 | span, | |
1955 | || None, | |
1956 | )? | |
c1a9b12d | 1957 | } |
ba9703b0 XL |
1958 | ( |
1959 | &ty::Param(_), | |
2b03887a | 1960 | Res::SelfTyParam { trait_: param_did } | Res::Def(DefKind::TyParam, param_did), |
f9f354fc | 1961 | ) => self.find_bound_for_assoc_item(param_did.expect_local(), assoc_ident, span)?, |
9fa01778 | 1962 | _ => { |
5e7ed085 | 1963 | let reported = if variant_resolution.is_some() { |
9fa01778 XL |
1964 | // Variant in type position |
1965 | let msg = format!("expected type, found variant `{}`", assoc_ident); | |
5e7ed085 | 1966 | tcx.sess.span_err(span, &msg) |
9fa01778 | 1967 | } else if qself_ty.is_enum() { |
dfeec247 XL |
1968 | let mut err = struct_span_err!( |
1969 | tcx.sess, | |
48663c56 | 1970 | assoc_ident.span, |
dfeec247 XL |
1971 | E0599, |
1972 | "no variant named `{}` found for enum `{}`", | |
1973 | assoc_ident, | |
1974 | qself_ty, | |
a1dfa0c6 | 1975 | ); |
48663c56 | 1976 | |
9fa01778 XL |
1977 | let adt_def = qself_ty.ty_adt_def().expect("enum is not an ADT"); |
1978 | if let Some(suggested_name) = find_best_match_for_name( | |
fc512014 | 1979 | &adt_def |
5e7ed085 | 1980 | .variants() |
fc512014 | 1981 | .iter() |
5099ac24 | 1982 | .map(|variant| variant.name) |
fc512014 | 1983 | .collect::<Vec<Symbol>>(), |
3dfed10e | 1984 | assoc_ident.name, |
9fa01778 XL |
1985 | None, |
1986 | ) { | |
1987 | err.span_suggestion( | |
48663c56 XL |
1988 | assoc_ident.span, |
1989 | "there is a variant with a similar name", | |
923072b8 | 1990 | suggested_name, |
9fa01778 XL |
1991 | Applicability::MaybeIncorrect, |
1992 | ); | |
1993 | } else { | |
416331ca XL |
1994 | err.span_label( |
1995 | assoc_ident.span, | |
1996 | format!("variant not found in `{}`", qself_ty), | |
1997 | ); | |
48663c56 XL |
1998 | } |
1999 | ||
5e7ed085 | 2000 | if let Some(sp) = tcx.hir().span_if_local(adt_def.did()) { |
48663c56 | 2001 | err.span_label(sp, format!("variant `{}` not found here", assoc_ident)); |
9fa01778 | 2002 | } |
48663c56 | 2003 | |
5e7ed085 | 2004 | err.emit() |
487cf647 | 2005 | } else if let Err(reported) = qself_ty.error_reported() { |
5e7ed085 FG |
2006 | reported |
2007 | } else { | |
9fa01778 | 2008 | // Don't print `TyErr` to the user. |
48663c56 XL |
2009 | self.report_ambiguous_associated_type( |
2010 | span, | |
2011 | &qself_ty.to_string(), | |
2012 | "Trait", | |
e1599b0c | 2013 | assoc_ident.name, |
5e7ed085 FG |
2014 | ) |
2015 | }; | |
2016 | return Err(reported); | |
9346a6ac | 2017 | } |
a7813a04 | 2018 | }; |
c34b1796 | 2019 | |
83c7162d | 2020 | let trait_did = bound.def_id(); |
487cf647 FG |
2021 | let Some(assoc_ty_did) = self.lookup_assoc_ty(assoc_ident, hir_ref_id, span, trait_did) else { |
2022 | // Assume that if it's not matched, there must be a const defined with the same name | |
2023 | // but it was used in a type position. | |
5099ac24 | 2024 | let msg = format!("found associated const `{assoc_ident}` when type was expected"); |
5e7ed085 FG |
2025 | let guar = tcx.sess.struct_span_err(span, &msg).emit(); |
2026 | return Err(guar); | |
5099ac24 | 2027 | }; |
041b39d2 | 2028 | |
487cf647 | 2029 | let ty = self.projected_ty_from_poly_trait_ref(span, assoc_ty_did, assoc_segment, bound); |
041b39d2 XL |
2030 | let ty = self.normalize_ty(span, ty); |
2031 | ||
48663c56 | 2032 | if let Some(variant_def_id) = variant_resolution { |
2b03887a FG |
2033 | tcx.struct_span_lint_hir( |
2034 | AMBIGUOUS_ASSOCIATED_ITEMS, | |
2035 | hir_ref_id, | |
2036 | span, | |
2037 | "ambiguous associated item", | |
2038 | |lint| { | |
2039 | let mut could_refer_to = |kind: DefKind, def_id, also| { | |
2040 | let note_msg = format!( | |
2041 | "`{}` could{} refer to the {} defined here", | |
2042 | assoc_ident, | |
2043 | also, | |
2044 | kind.descr(def_id) | |
2045 | ); | |
2046 | lint.span_note(tcx.def_span(def_id), ¬e_msg); | |
2047 | }; | |
9fa01778 | 2048 | |
2b03887a | 2049 | could_refer_to(DefKind::Variant, variant_def_id, ""); |
487cf647 | 2050 | could_refer_to(DefKind::AssocTy, assoc_ty_did, " also"); |
74b04a01 | 2051 | |
2b03887a FG |
2052 | lint.span_suggestion( |
2053 | span, | |
2054 | "use fully-qualified syntax", | |
2055 | format!("<{} as {}>::{}", qself_ty, tcx.item_name(trait_did), assoc_ident), | |
2056 | Applicability::MachineApplicable, | |
2057 | ); | |
9fa01778 | 2058 | |
2b03887a FG |
2059 | lint |
2060 | }, | |
2061 | ); | |
9fa01778 | 2062 | } |
487cf647 FG |
2063 | Ok((ty, DefKind::AssocTy, assoc_ty_did)) |
2064 | } | |
2065 | ||
2066 | fn lookup_assoc_ty( | |
2067 | &self, | |
2068 | ident: Ident, | |
2069 | block: hir::HirId, | |
2070 | span: Span, | |
2071 | scope: DefId, | |
2072 | ) -> Option<DefId> { | |
2073 | let tcx = self.tcx(); | |
2074 | let (ident, def_scope) = tcx.adjust_ident_and_get_scope(ident, scope, block); | |
2075 | ||
2076 | // We have already adjusted the item name above, so compare with `ident.normalize_to_macros_2_0()` instead | |
2077 | // of calling `find_by_name_and_kind`. | |
2078 | let item = tcx.associated_items(scope).in_definition_order().find(|i| { | |
2079 | i.kind.namespace() == Namespace::TypeNS | |
2080 | && i.ident(tcx).normalize_to_macros_2_0() == ident | |
2081 | })?; | |
2082 | ||
2083 | let kind = DefKind::AssocTy; | |
2084 | if !item.visibility(tcx).is_accessible_from(def_scope, tcx) { | |
2085 | let kind = kind.descr(item.def_id); | |
2086 | let msg = format!("{kind} `{ident}` is private"); | |
2087 | let def_span = self.tcx().def_span(item.def_id); | |
2088 | tcx.sess | |
2089 | .struct_span_err_with_code(span, &msg, rustc_errors::error_code!(E0624)) | |
2090 | .span_label(span, &format!("private {kind}")) | |
2091 | .span_label(def_span, &format!("{kind} defined here")) | |
2092 | .emit(); | |
2093 | } | |
2094 | tcx.check_stability(item.def_id, Some(block), span, None); | |
2095 | ||
2096 | Some(item.def_id) | |
a7813a04 | 2097 | } |
1a4d82fc | 2098 | |
dfeec247 XL |
2099 | fn qpath_to_ty( |
2100 | &self, | |
2101 | span: Span, | |
2102 | opt_self_ty: Option<Ty<'tcx>>, | |
2103 | item_def_id: DefId, | |
2104 | trait_segment: &hir::PathSegment<'_>, | |
2105 | item_segment: &hir::PathSegment<'_>, | |
2b03887a | 2106 | constness: ty::BoundConstness, |
dfeec247 | 2107 | ) -> Ty<'tcx> { |
a7813a04 | 2108 | let tcx = self.tcx(); |
60c5eb7d | 2109 | |
04454e1e | 2110 | let trait_def_id = tcx.parent(item_def_id); |
1a4d82fc | 2111 | |
60c5eb7d XL |
2112 | debug!("qpath_to_ty: trait_def_id={:?}", trait_def_id); |
2113 | ||
3c0e092e | 2114 | let Some(self_ty) = opt_self_ty else { |
532ac7d7 | 2115 | let path_str = tcx.def_path_str(trait_def_id); |
60c5eb7d XL |
2116 | |
2117 | let def_id = self.item_def_id(); | |
2118 | ||
2119 | debug!("qpath_to_ty: self.item_def_id()={:?}", def_id); | |
2120 | ||
487cf647 | 2121 | let parent_def_id = def_id.as_local().map(|def_id| tcx.hir().local_def_id_to_hir_id(def_id)) |
5099ac24 | 2122 | .map(|hir_id| tcx.hir().get_parent_item(hir_id).to_def_id()); |
60c5eb7d XL |
2123 | |
2124 | debug!("qpath_to_ty: parent_def_id={:?}", parent_def_id); | |
2125 | ||
2126 | // If the trait in segment is the same as the trait defining the item, | |
2127 | // use the `<Self as ..>` syntax in the error. | |
487cf647 | 2128 | let is_part_of_self_trait_constraints = def_id == trait_def_id; |
60c5eb7d XL |
2129 | let is_part_of_fn_in_self_trait = parent_def_id == Some(trait_def_id); |
2130 | ||
2131 | let type_name = if is_part_of_self_trait_constraints || is_part_of_fn_in_self_trait { | |
2132 | "Self" | |
2133 | } else { | |
2134 | "Type" | |
2135 | }; | |
2136 | ||
487cf647 | 2137 | let reported = self.report_ambiguous_associated_type( |
48663c56 | 2138 | span, |
60c5eb7d | 2139 | type_name, |
48663c56 | 2140 | &path_str, |
e1599b0c | 2141 | item_segment.ident.name, |
48663c56 | 2142 | ); |
487cf647 | 2143 | return tcx.ty_error_with_guaranteed(reported) |
a7813a04 | 2144 | }; |
1a4d82fc | 2145 | |
a7813a04 | 2146 | debug!("qpath_to_ty: self_type={:?}", self_ty); |
1a4d82fc | 2147 | |
2b03887a FG |
2148 | let trait_ref = self.ast_path_to_mono_trait_ref( |
2149 | span, | |
2150 | trait_def_id, | |
2151 | self_ty, | |
2152 | trait_segment, | |
2153 | false, | |
487cf647 | 2154 | constness, |
2b03887a | 2155 | ); |
dfeec247 XL |
2156 | |
2157 | let item_substs = self.create_substs_for_associated_item( | |
dfeec247 XL |
2158 | span, |
2159 | item_def_id, | |
2160 | item_segment, | |
2161 | trait_ref.substs, | |
2162 | ); | |
1a4d82fc | 2163 | |
a7813a04 | 2164 | debug!("qpath_to_ty: trait_ref={:?}", trait_ref); |
85aaf69f | 2165 | |
dfeec247 | 2166 | self.normalize_ty(span, tcx.mk_projection(item_def_id, item_substs)) |
8bb4bdeb XL |
2167 | } |
2168 | ||
923072b8 | 2169 | pub fn prohibit_generics<'a>( |
dfeec247 | 2170 | &self, |
923072b8 | 2171 | segments: impl Iterator<Item = &'a hir::PathSegment<'a>> + Clone, |
f2b60f7d | 2172 | extend: impl Fn(&mut Diagnostic), |
dfeec247 | 2173 | ) -> bool { |
923072b8 FG |
2174 | let args = segments.clone().flat_map(|segment| segment.args().args); |
2175 | ||
2176 | let (lt, ty, ct, inf) = | |
2177 | args.clone().fold((false, false, false, false), |(lt, ty, ct, inf), arg| match arg { | |
2178 | hir::GenericArg::Lifetime(_) => (true, ty, ct, inf), | |
2179 | hir::GenericArg::Type(_) => (lt, true, ct, inf), | |
2180 | hir::GenericArg::Const(_) => (lt, ty, true, inf), | |
2181 | hir::GenericArg::Infer(_) => (lt, ty, ct, true), | |
2182 | }); | |
2183 | let mut emitted = false; | |
2184 | if lt || ty || ct || inf { | |
2185 | let types_and_spans: Vec<_> = segments | |
2186 | .clone() | |
2187 | .flat_map(|segment| { | |
f2b60f7d FG |
2188 | if segment.args().args.is_empty() { |
2189 | None | |
2190 | } else { | |
2191 | Some(( | |
2192 | match segment.res { | |
2193 | Res::PrimTy(ty) => format!("{} `{}`", segment.res.descr(), ty.name()), | |
923072b8 FG |
2194 | Res::Def(_, def_id) |
2195 | if let Some(name) = self.tcx().opt_item_name(def_id) => { | |
f2b60f7d | 2196 | format!("{} `{name}`", segment.res.descr()) |
923072b8 FG |
2197 | } |
2198 | Res::Err => "this type".to_string(), | |
f2b60f7d | 2199 | _ => segment.res.descr().to_string(), |
923072b8 FG |
2200 | }, |
2201 | segment.ident.span, | |
2202 | )) | |
f2b60f7d | 2203 | } |
923072b8 FG |
2204 | }) |
2205 | .collect(); | |
2206 | let this_type = match &types_and_spans[..] { | |
2207 | [.., _, (last, _)] => format!( | |
2208 | "{} and {last}", | |
2209 | types_and_spans[..types_and_spans.len() - 1] | |
2210 | .iter() | |
2211 | .map(|(x, _)| x.as_str()) | |
2212 | .intersperse(&", ") | |
2213 | .collect::<String>() | |
2214 | ), | |
2215 | [(only, _)] => only.to_string(), | |
2216 | [] => "this type".to_string(), | |
2217 | }; | |
2218 | ||
2219 | let arg_spans: Vec<Span> = args.map(|arg| arg.span()).collect(); | |
2220 | ||
2221 | let mut kinds = Vec::with_capacity(4); | |
2222 | if lt { | |
2223 | kinds.push("lifetime"); | |
2224 | } | |
2225 | if ty { | |
2226 | kinds.push("type"); | |
2227 | } | |
2228 | if ct { | |
2229 | kinds.push("const"); | |
dc9dc135 | 2230 | } |
923072b8 FG |
2231 | if inf { |
2232 | kinds.push("generic"); | |
2233 | } | |
2234 | let (kind, s) = match kinds[..] { | |
2235 | [.., _, last] => ( | |
2236 | format!( | |
2237 | "{} and {last}", | |
2238 | kinds[..kinds.len() - 1] | |
2239 | .iter() | |
2240 | .map(|&x| x) | |
2241 | .intersperse(", ") | |
2242 | .collect::<String>() | |
2243 | ), | |
2244 | "s", | |
2245 | ), | |
2246 | [only] => (format!("{only}"), ""), | |
2247 | [] => unreachable!(), | |
2248 | }; | |
2249 | let last_span = *arg_spans.last().unwrap(); | |
2250 | let span: MultiSpan = arg_spans.into(); | |
2251 | let mut err = struct_span_err!( | |
2252 | self.tcx().sess, | |
2253 | span, | |
2254 | E0109, | |
2255 | "{kind} arguments are not allowed on {this_type}", | |
2256 | ); | |
2257 | err.span_label(last_span, format!("{kind} argument{s} not allowed")); | |
2258 | for (what, span) in types_and_spans { | |
2259 | err.span_label(span, format!("not allowed on {what}")); | |
2260 | } | |
2261 | extend(&mut err); | |
2262 | err.emit(); | |
2263 | emitted = true; | |
2264 | } | |
74b04a01 | 2265 | |
923072b8 | 2266 | for segment in segments { |
74b04a01 | 2267 | // Only emit the first error to avoid overloading the user with error messages. |
2b03887a FG |
2268 | if let Some(b) = segment.args().bindings.first() { |
2269 | Self::prohibit_assoc_ty_binding(self.tcx(), b.span); | |
923072b8 | 2270 | return true; |
dc9dc135 | 2271 | } |
8bb4bdeb | 2272 | } |
923072b8 | 2273 | emitted |
8bb4bdeb XL |
2274 | } |
2275 | ||
48663c56 XL |
2276 | // FIXME(eddyb, varkor) handle type paths here too, not just value ones. |
2277 | pub fn def_ids_for_value_path_segments( | |
2278 | &self, | |
dfeec247 | 2279 | segments: &[hir::PathSegment<'_>], |
48663c56 XL |
2280 | self_ty: Option<Ty<'tcx>>, |
2281 | kind: DefKind, | |
2282 | def_id: DefId, | |
2283 | ) -> Vec<PathSeg> { | |
0731742a XL |
2284 | // We need to extract the type parameters supplied by the user in |
2285 | // the path `path`. Due to the current setup, this is a bit of a | |
2286 | // tricky-process; the problem is that resolve only tells us the | |
2287 | // end-point of the path resolution, and not the intermediate steps. | |
2288 | // Luckily, we can (at least for now) deduce the intermediate steps | |
2289 | // just from the end-point. | |
2290 | // | |
2291 | // There are basically five cases to consider: | |
2292 | // | |
2293 | // 1. Reference to a constructor of a struct: | |
2294 | // | |
2295 | // struct Foo<T>(...) | |
2296 | // | |
2297 | // In this case, the parameters are declared in the type space. | |
2298 | // | |
2299 | // 2. Reference to a constructor of an enum variant: | |
2300 | // | |
2301 | // enum E<T> { Foo(...) } | |
2302 | // | |
2303 | // In this case, the parameters are defined in the type space, | |
2304 | // but may be specified either on the type or the variant. | |
2305 | // | |
2306 | // 3. Reference to a fn item or a free constant: | |
2307 | // | |
2308 | // fn foo<T>() { } | |
2309 | // | |
2310 | // In this case, the path will again always have the form | |
2311 | // `a::b::foo::<T>` where only the final segment should have | |
2312 | // type parameters. However, in this case, those parameters are | |
2313 | // declared on a value, and hence are in the `FnSpace`. | |
2314 | // | |
2315 | // 4. Reference to a method or an associated constant: | |
2316 | // | |
2317 | // impl<A> SomeStruct<A> { | |
2318 | // fn foo<B>(...) | |
2319 | // } | |
2320 | // | |
2321 | // Here we can have a path like | |
2322 | // `a::b::SomeStruct::<A>::foo::<B>`, in which case parameters | |
2323 | // may appear in two places. The penultimate segment, | |
2324 | // `SomeStruct::<A>`, contains parameters in TypeSpace, and the | |
2325 | // final segment, `foo::<B>` contains parameters in fn space. | |
2326 | // | |
0731742a XL |
2327 | // The first step then is to categorize the segments appropriately. |
2328 | ||
2329 | let tcx = self.tcx(); | |
2330 | ||
2331 | assert!(!segments.is_empty()); | |
2332 | let last = segments.len() - 1; | |
2333 | ||
2334 | let mut path_segs = vec![]; | |
2335 | ||
48663c56 | 2336 | match kind { |
0731742a | 2337 | // Case 1. Reference to a struct constructor. |
48663c56 | 2338 | DefKind::Ctor(CtorOf::Struct, ..) => { |
0731742a XL |
2339 | // Everything but the final segment should have no |
2340 | // parameters at all. | |
2341 | let generics = tcx.generics_of(def_id); | |
2342 | // Variant and struct constructors use the | |
2343 | // generics of their parent type definition. | |
2344 | let generics_def_id = generics.parent.unwrap_or(def_id); | |
2345 | path_segs.push(PathSeg(generics_def_id, last)); | |
2346 | } | |
2347 | ||
2348 | // Case 2. Reference to a variant constructor. | |
dfeec247 | 2349 | DefKind::Ctor(CtorOf::Variant, ..) | DefKind::Variant => { |
0731742a XL |
2350 | let adt_def = self_ty.map(|t| t.ty_adt_def().unwrap()); |
2351 | let (generics_def_id, index) = if let Some(adt_def) = adt_def { | |
2352 | debug_assert!(adt_def.is_enum()); | |
5e7ed085 | 2353 | (adt_def.did(), last) |
0731742a XL |
2354 | } else if last >= 1 && segments[last - 1].args.is_some() { |
2355 | // Everything but the penultimate segment should have no | |
2356 | // parameters at all. | |
532ac7d7 XL |
2357 | let mut def_id = def_id; |
2358 | ||
48663c56 XL |
2359 | // `DefKind::Ctor` -> `DefKind::Variant` |
2360 | if let DefKind::Ctor(..) = kind { | |
04454e1e | 2361 | def_id = tcx.parent(def_id); |
532ac7d7 XL |
2362 | } |
2363 | ||
48663c56 | 2364 | // `DefKind::Variant` -> `DefKind::Enum` |
04454e1e | 2365 | let enum_def_id = tcx.parent(def_id); |
0731742a XL |
2366 | (enum_def_id, last - 1) |
2367 | } else { | |
2368 | // FIXME: lint here recommending `Enum::<...>::Variant` form | |
2369 | // instead of `Enum::Variant::<...>` form. | |
2370 | ||
2371 | // Everything but the final segment should have no | |
2372 | // parameters at all. | |
2373 | let generics = tcx.generics_of(def_id); | |
2374 | // Variant and struct constructors use the | |
2375 | // generics of their parent type definition. | |
2376 | (generics.parent.unwrap_or(def_id), last) | |
2377 | }; | |
2378 | path_segs.push(PathSeg(generics_def_id, index)); | |
2379 | } | |
2380 | ||
2381 | // Case 3. Reference to a top-level value. | |
5e7ed085 | 2382 | DefKind::Fn | DefKind::Const | DefKind::ConstParam | DefKind::Static(_) => { |
0731742a XL |
2383 | path_segs.push(PathSeg(def_id, last)); |
2384 | } | |
2385 | ||
2386 | // Case 4. Reference to a method or associated const. | |
ba9703b0 | 2387 | DefKind::AssocFn | DefKind::AssocConst => { |
0731742a XL |
2388 | if segments.len() >= 2 { |
2389 | let generics = tcx.generics_of(def_id); | |
2390 | path_segs.push(PathSeg(generics.parent.unwrap(), last - 1)); | |
2391 | } | |
2392 | path_segs.push(PathSeg(def_id, last)); | |
2393 | } | |
2394 | ||
48663c56 | 2395 | kind => bug!("unexpected definition kind {:?} for {:?}", kind, def_id), |
0731742a XL |
2396 | } |
2397 | ||
2398 | debug!("path_segs = {:?}", path_segs); | |
2399 | ||
2400 | path_segs | |
2401 | } | |
2402 | ||
487cf647 | 2403 | /// Check a type `Path` and convert it to a `Ty`. |
dfeec247 XL |
2404 | pub fn res_to_ty( |
2405 | &self, | |
2406 | opt_self_ty: Option<Ty<'tcx>>, | |
2407 | path: &hir::Path<'_>, | |
2408 | permit_variants: bool, | |
2409 | ) -> Ty<'tcx> { | |
a7813a04 XL |
2410 | let tcx = self.tcx(); |
2411 | ||
dfeec247 XL |
2412 | debug!( |
2413 | "res_to_ty(res={:?}, opt_self_ty={:?}, path_segments={:?})", | |
2414 | path.res, opt_self_ty, path.segments | |
2415 | ); | |
a7813a04 | 2416 | |
476ff2be | 2417 | let span = path.span; |
48663c56 | 2418 | match path.res { |
f2b60f7d | 2419 | Res::Def(DefKind::OpaqueTy | DefKind::ImplTraitPlaceholder, did) => { |
dc9dc135 | 2420 | // Check for desugared `impl Trait`. |
487cf647 | 2421 | assert!(tcx.is_type_alias_impl_trait(did)); |
8faf50e0 | 2422 | let item_segment = path.segments.split_last().unwrap(); |
923072b8 FG |
2423 | self.prohibit_generics(item_segment.1.iter(), |err| { |
2424 | err.note("`impl Trait` types can't have type parameters"); | |
2425 | }); | |
8faf50e0 | 2426 | let substs = self.ast_path_substs_for_ty(span, did, item_segment.0); |
dfeec247 | 2427 | self.normalize_ty(span, tcx.mk_opaque(did, substs)) |
8faf50e0 | 2428 | } |
ba9703b0 XL |
2429 | Res::Def( |
2430 | DefKind::Enum | |
2431 | | DefKind::TyAlias | |
2432 | | DefKind::Struct | |
2433 | | DefKind::Union | |
2434 | | DefKind::ForeignTy, | |
2435 | did, | |
2436 | ) => { | |
476ff2be | 2437 | assert_eq!(opt_self_ty, None); |
923072b8 | 2438 | self.prohibit_generics(path.segments.split_last().unwrap().1.iter(), |_| {}); |
32a655c1 | 2439 | self.ast_path_to_ty(span, did, path.segments.last().unwrap()) |
a7813a04 | 2440 | } |
48663c56 | 2441 | Res::Def(kind @ DefKind::Variant, def_id) if permit_variants => { |
c30ab7b3 SL |
2442 | // Convert "variant type" as if it were a real type. |
2443 | // The resulting `Ty` is type of the variant's enum for now. | |
476ff2be | 2444 | assert_eq!(opt_self_ty, None); |
0731742a | 2445 | |
48663c56 | 2446 | let path_segs = |
c295e0f8 | 2447 | self.def_ids_for_value_path_segments(path.segments, None, kind, def_id); |
0731742a XL |
2448 | let generic_segs: FxHashSet<_> = |
2449 | path_segs.iter().map(|PathSeg(_, index)| index).collect(); | |
923072b8 FG |
2450 | self.prohibit_generics( |
2451 | path.segments.iter().enumerate().filter_map(|(index, seg)| { | |
dfeec247 | 2452 | if !generic_segs.contains(&index) { Some(seg) } else { None } |
923072b8 FG |
2453 | }), |
2454 | |err| { | |
2455 | err.note("enum variants can't have type parameters"); | |
dfeec247 | 2456 | }, |
923072b8 | 2457 | ); |
0731742a XL |
2458 | |
2459 | let PathSeg(def_id, index) = path_segs.last().unwrap(); | |
2460 | self.ast_path_to_ty(span, *def_id, &path.segments[*index]) | |
c30ab7b3 | 2461 | } |
dc9dc135 | 2462 | Res::Def(DefKind::TyParam, def_id) => { |
476ff2be | 2463 | assert_eq!(opt_self_ty, None); |
923072b8 FG |
2464 | self.prohibit_generics(path.segments.iter(), |err| { |
2465 | if let Some(span) = tcx.def_ident_span(def_id) { | |
2466 | let name = tcx.item_name(def_id); | |
2467 | err.span_note(span, &format!("type parameter `{name}` defined here")); | |
2468 | } | |
2469 | }); | |
9e0c209e | 2470 | |
04454e1e FG |
2471 | let def_id = def_id.expect_local(); |
2472 | let item_def_id = tcx.hir().ty_param_owner(def_id); | |
7cac9316 | 2473 | let generics = tcx.generics_of(item_def_id); |
04454e1e FG |
2474 | let index = generics.param_def_id_to_index[&def_id.to_def_id()]; |
2475 | tcx.mk_ty_param(index, tcx.hir().ty_param_name(def_id)) | |
a7813a04 | 2476 | } |
2b03887a | 2477 | Res::SelfTyParam { .. } => { |
dc9dc135 | 2478 | // `Self` in trait or type alias. |
476ff2be | 2479 | assert_eq!(opt_self_ty, None); |
923072b8 FG |
2480 | self.prohibit_generics(path.segments.iter(), |err| { |
2481 | if let [hir::PathSegment { args: Some(args), ident, .. }] = &path.segments[..] { | |
2482 | err.span_suggestion_verbose( | |
2483 | ident.span.shrink_to_hi().to(args.span_ext), | |
2484 | "the `Self` type doesn't accept type parameters", | |
2485 | "", | |
2486 | Applicability::MaybeIncorrect, | |
2487 | ); | |
2488 | } | |
2489 | }); | |
e1599b0c | 2490 | tcx.types.self_param |
9346a6ac | 2491 | } |
2b03887a | 2492 | Res::SelfTyAlias { alias_to: def_id, forbid_generic, .. } => { |
dc9dc135 | 2493 | // `Self` in impl (we know the concrete type). |
476ff2be | 2494 | assert_eq!(opt_self_ty, None); |
dc9dc135 | 2495 | // Try to evaluate any array length constants. |
5099ac24 | 2496 | let ty = tcx.at(span).type_of(def_id); |
923072b8 FG |
2497 | let span_of_impl = tcx.span_of_impl(def_id); |
2498 | self.prohibit_generics(path.segments.iter(), |err| { | |
2499 | let def_id = match *ty.kind() { | |
2500 | ty::Adt(self_def, _) => self_def.did(), | |
2501 | _ => return, | |
2502 | }; | |
2503 | ||
2504 | let type_name = tcx.item_name(def_id); | |
2505 | let span_of_ty = tcx.def_ident_span(def_id); | |
2506 | let generics = tcx.generics_of(def_id).count(); | |
2507 | ||
2508 | let msg = format!("`Self` is of type `{ty}`"); | |
2509 | if let (Ok(i_sp), Some(t_sp)) = (span_of_impl, span_of_ty) { | |
923072b8 FG |
2510 | let mut span: MultiSpan = vec![t_sp].into(); |
2511 | span.push_span_label( | |
2512 | i_sp, | |
2513 | &format!("`Self` is on type `{type_name}` in this `impl`"), | |
2514 | ); | |
2515 | let mut postfix = ""; | |
2516 | if generics == 0 { | |
2517 | postfix = ", which doesn't have generic parameters"; | |
2518 | } | |
2519 | span.push_span_label( | |
2520 | t_sp, | |
2521 | &format!("`Self` corresponds to this type{postfix}"), | |
2522 | ); | |
2523 | err.span_note(span, &msg); | |
2524 | } else { | |
2525 | err.note(&msg); | |
2526 | } | |
2527 | for segment in path.segments { | |
2528 | if let Some(args) = segment.args && segment.ident.name == kw::SelfUpper { | |
2529 | if generics == 0 { | |
2530 | // FIXME(estebank): we could also verify that the arguments being | |
2531 | // work for the `enum`, instead of just looking if it takes *any*. | |
2532 | err.span_suggestion_verbose( | |
2533 | segment.ident.span.shrink_to_hi().to(args.span_ext), | |
2534 | "the `Self` type doesn't accept type parameters", | |
2535 | "", | |
2536 | Applicability::MachineApplicable, | |
2537 | ); | |
2538 | return; | |
2539 | } else { | |
2540 | err.span_suggestion_verbose( | |
2541 | segment.ident.span, | |
2542 | format!( | |
2543 | "the `Self` type doesn't accept type parameters, use the \ | |
2544 | concrete type's name `{type_name}` instead if you want to \ | |
2545 | specify its type parameters" | |
2546 | ), | |
064997fb | 2547 | type_name, |
923072b8 FG |
2548 | Applicability::MaybeIncorrect, |
2549 | ); | |
2550 | } | |
2551 | } | |
2552 | } | |
2553 | }); | |
5099ac24 FG |
2554 | // HACK(min_const_generics): Forbid generic `Self` types |
2555 | // here as we can't easily do that during nameres. | |
2556 | // | |
2557 | // We do this before normalization as we otherwise allow | |
2558 | // ```rust | |
2559 | // trait AlwaysApplicable { type Assoc; } | |
2560 | // impl<T: ?Sized> AlwaysApplicable for T { type Assoc = usize; } | |
2561 | // | |
2562 | // trait BindsParam<T> { | |
2563 | // type ArrayTy; | |
2564 | // } | |
2565 | // impl<T> BindsParam<T> for <T as AlwaysApplicable>::Assoc { | |
2566 | // type ArrayTy = [u8; Self::MAX]; | |
2567 | // } | |
2568 | // ``` | |
2569 | // Note that the normalization happens in the param env of | |
2570 | // the anon const, which is empty. This is why the | |
2571 | // `AlwaysApplicable` impl needs a `T: ?Sized` bound for | |
2572 | // this to compile if we were to normalize here. | |
2573 | if forbid_generic && ty.needs_subst() { | |
1b1a35ee XL |
2574 | let mut err = tcx.sess.struct_span_err( |
2575 | path.span, | |
2576 | "generic `Self` types are currently not permitted in anonymous constants", | |
2577 | ); | |
2578 | if let Some(hir::Node::Item(&hir::Item { | |
5869c6ff | 2579 | kind: hir::ItemKind::Impl(ref impl_), |
1b1a35ee XL |
2580 | .. |
2581 | })) = tcx.hir().get_if_local(def_id) | |
2582 | { | |
5869c6ff | 2583 | err.span_note(impl_.self_ty.span, "not a concrete type"); |
1b1a35ee | 2584 | } |
487cf647 | 2585 | tcx.ty_error_with_guaranteed(err.emit()) |
1b1a35ee | 2586 | } else { |
5099ac24 | 2587 | self.normalize_ty(span, ty) |
1b1a35ee | 2588 | } |
a7813a04 | 2589 | } |
dc9dc135 | 2590 | Res::Def(DefKind::AssocTy, def_id) => { |
0731742a | 2591 | debug_assert!(path.segments.len() >= 2); |
923072b8 | 2592 | self.prohibit_generics(path.segments[..path.segments.len() - 2].iter(), |_| {}); |
2b03887a FG |
2593 | // HACK: until we support `<Type as ~const Trait>`, assume all of them are. |
2594 | let constness = if tcx.has_attr(tcx.parent(def_id), sym::const_trait) { | |
2595 | ty::BoundConstness::ConstIfConst | |
2596 | } else { | |
2597 | ty::BoundConstness::NotConst | |
2598 | }; | |
dfeec247 XL |
2599 | self.qpath_to_ty( |
2600 | span, | |
2601 | opt_self_ty, | |
2602 | def_id, | |
2603 | &path.segments[path.segments.len() - 2], | |
2604 | path.segments.last().unwrap(), | |
2b03887a | 2605 | constness, |
dfeec247 | 2606 | ) |
a7813a04 | 2607 | } |
48663c56 | 2608 | Res::PrimTy(prim_ty) => { |
476ff2be | 2609 | assert_eq!(opt_self_ty, None); |
923072b8 FG |
2610 | self.prohibit_generics(path.segments.iter(), |err| { |
2611 | let name = prim_ty.name_str(); | |
2612 | for segment in path.segments { | |
2613 | if let Some(args) = segment.args { | |
2614 | err.span_suggestion_verbose( | |
2615 | segment.ident.span.shrink_to_hi().to(args.span_ext), | |
2616 | &format!("primitive type `{name}` doesn't have generic parameters"), | |
2617 | "", | |
2618 | Applicability::MaybeIncorrect, | |
2619 | ); | |
2620 | } | |
2621 | } | |
2622 | }); | |
8bb4bdeb | 2623 | match prim_ty { |
dfeec247 XL |
2624 | hir::PrimTy::Bool => tcx.types.bool, |
2625 | hir::PrimTy::Char => tcx.types.char, | |
5869c6ff XL |
2626 | hir::PrimTy::Int(it) => tcx.mk_mach_int(ty::int_ty(it)), |
2627 | hir::PrimTy::Uint(uit) => tcx.mk_mach_uint(ty::uint_ty(uit)), | |
2628 | hir::PrimTy::Float(ft) => tcx.mk_mach_float(ty::float_ty(ft)), | |
f035d41b | 2629 | hir::PrimTy::Str => tcx.types.str_, |
8bb4bdeb | 2630 | } |
a7813a04 | 2631 | } |
48663c56 | 2632 | Res::Err => { |
487cf647 FG |
2633 | let e = self |
2634 | .tcx() | |
2635 | .sess | |
2636 | .delay_span_bug(path.span, "path with `Res:Err` but no error emitted"); | |
2637 | self.set_tainted_by_errors(e); | |
2638 | self.tcx().ty_error_with_guaranteed(e) | |
a7813a04 | 2639 | } |
dfeec247 | 2640 | _ => span_bug!(span, "unexpected resolution: {:?}", path.res), |
c34b1796 | 2641 | } |
9346a6ac | 2642 | } |
c34b1796 | 2643 | |
a7813a04 XL |
2644 | /// Parses the programmer's textual representation of a type into our |
2645 | /// internal notion of a type. | |
dfeec247 | 2646 | pub fn ast_ty_to_ty(&self, ast_ty: &hir::Ty<'_>) -> Ty<'tcx> { |
a2a8927a XL |
2647 | self.ast_ty_to_ty_inner(ast_ty, false, false) |
2648 | } | |
2649 | ||
2650 | /// Parses the programmer's textual representation of a type into our | |
2651 | /// internal notion of a type. This is meant to be used within a path. | |
2652 | pub fn ast_ty_to_ty_in_path(&self, ast_ty: &hir::Ty<'_>) -> Ty<'tcx> { | |
2653 | self.ast_ty_to_ty_inner(ast_ty, false, true) | |
3dfed10e XL |
2654 | } |
2655 | ||
2656 | /// Turns a `hir::Ty` into a `Ty`. For diagnostics' purposes we keep track of whether trait | |
2657 | /// objects are borrowed like `&dyn Trait` to avoid emitting redundant errors. | |
f2b60f7d | 2658 | #[instrument(level = "debug", skip(self), ret)] |
a2a8927a | 2659 | fn ast_ty_to_ty_inner(&self, ast_ty: &hir::Ty<'_>, borrowed: bool, in_path: bool) -> Ty<'tcx> { |
a7813a04 | 2660 | let tcx = self.tcx(); |
1a4d82fc | 2661 | |
e74abb32 | 2662 | let result_ty = match ast_ty.kind { |
c295e0f8 | 2663 | hir::TyKind::Slice(ref ty) => tcx.mk_slice(self.ast_ty_to_ty(ty)), |
8faf50e0 | 2664 | hir::TyKind::Ptr(ref mt) => { |
c295e0f8 | 2665 | tcx.mk_ptr(ty::TypeAndMut { ty: self.ast_ty_to_ty(mt.ty), mutbl: mt.mutbl }) |
a7813a04 | 2666 | } |
8faf50e0 | 2667 | hir::TyKind::Rptr(ref region, ref mt) => { |
32a655c1 | 2668 | let r = self.ast_region_to_region(region, None); |
cdc7bbd5 | 2669 | debug!(?r); |
a2a8927a | 2670 | let t = self.ast_ty_to_ty_inner(mt.ty, true, false); |
dfeec247 | 2671 | tcx.mk_ref(r, ty::TypeAndMut { ty: t, mutbl: mt.mutbl }) |
a7813a04 | 2672 | } |
dfeec247 | 2673 | hir::TyKind::Never => tcx.types.never, |
c295e0f8 XL |
2674 | hir::TyKind::Tup(fields) => tcx.mk_tup(fields.iter().map(|t| self.ast_ty_to_ty(t))), |
2675 | hir::TyKind::BareFn(bf) => { | |
2676 | require_c_abi_if_c_variadic(tcx, bf.decl, bf.abi, ast_ty.span); | |
6a06907d | 2677 | |
74b04a01 | 2678 | tcx.mk_fn_ptr(self.ty_of_fn( |
cdc7bbd5 | 2679 | ast_ty.hir_id, |
74b04a01 XL |
2680 | bf.unsafety, |
2681 | bf.abi, | |
c295e0f8 | 2682 | bf.decl, |
74b04a01 | 2683 | None, |
6a06907d | 2684 | Some(ast_ty), |
74b04a01 | 2685 | )) |
1a4d82fc | 2686 | } |
f2b60f7d | 2687 | hir::TyKind::TraitObject(bounds, ref lifetime, repr) => { |
a2a8927a | 2688 | self.maybe_lint_bare_trait(ast_ty, in_path); |
f2b60f7d FG |
2689 | let repr = match repr { |
2690 | TraitObjectSyntax::Dyn | TraitObjectSyntax::None => ty::Dyn, | |
2691 | TraitObjectSyntax::DynStar => ty::DynStar, | |
2692 | }; | |
2693 | self.conv_object_ty_poly_trait_ref(ast_ty.span, bounds, lifetime, borrowed, repr) | |
a7813a04 | 2694 | } |
8faf50e0 | 2695 | hir::TyKind::Path(hir::QPath::Resolved(ref maybe_qself, ref path)) => { |
cdc7bbd5 | 2696 | debug!(?maybe_qself, ?path); |
dfeec247 | 2697 | let opt_self_ty = maybe_qself.as_ref().map(|qself| self.ast_ty_to_ty(qself)); |
48663c56 | 2698 | self.res_to_ty(opt_self_ty, path, false) |
476ff2be | 2699 | } |
f2b60f7d | 2700 | hir::TyKind::OpaqueDef(item_id, lifetimes, in_trait) => { |
6a06907d | 2701 | let opaque_ty = tcx.hir().item(item_id); |
2b03887a | 2702 | let def_id = item_id.owner_id.to_def_id(); |
f035d41b XL |
2703 | |
2704 | match opaque_ty.kind { | |
923072b8 | 2705 | hir::ItemKind::OpaqueTy(hir::OpaqueTy { origin, .. }) => { |
f2b60f7d | 2706 | self.impl_trait_ty_to_ty(def_id, lifetimes, origin, in_trait) |
923072b8 | 2707 | } |
f035d41b XL |
2708 | ref i => bug!("`impl Trait` pointed to non-opaque type?? {:#?}", i), |
2709 | } | |
dc9dc135 | 2710 | } |
8faf50e0 | 2711 | hir::TyKind::Path(hir::QPath::TypeRelative(ref qself, ref segment)) => { |
cdc7bbd5 | 2712 | debug!(?qself, ?segment); |
a2a8927a | 2713 | let ty = self.ast_ty_to_ty_inner(qself, false, true); |
923072b8 | 2714 | self.associated_path_to_ty(ast_ty.hir_id, ast_ty.span, ty, qself, segment, false) |
dfeec247 | 2715 | .map(|(ty, _, _)| ty) |
f035d41b | 2716 | .unwrap_or_else(|_| tcx.ty_error()) |
a7813a04 | 2717 | } |
a2a8927a | 2718 | hir::TyKind::Path(hir::QPath::LangItem(lang_item, span, _)) => { |
3dfed10e | 2719 | let def_id = tcx.require_lang_item(lang_item, Some(span)); |
cdc7bbd5 | 2720 | let (substs, _) = self.create_substs_for_ast_path( |
3dfed10e XL |
2721 | span, |
2722 | def_id, | |
2723 | &[], | |
5869c6ff | 2724 | &hir::PathSegment::invalid(), |
3dfed10e XL |
2725 | &GenericArgs::none(), |
2726 | true, | |
2727 | None, | |
487cf647 | 2728 | ty::BoundConstness::NotConst, |
3dfed10e | 2729 | ); |
04454e1e FG |
2730 | EarlyBinder(self.normalize_ty(span, tcx.at(span).type_of(def_id))) |
2731 | .subst(tcx, substs) | |
3dfed10e | 2732 | } |
8faf50e0 | 2733 | hir::TyKind::Array(ref ty, ref length) => { |
a2a8927a XL |
2734 | let length = match length { |
2735 | &hir::ArrayLen::Infer(_, span) => self.ct_infer(tcx.types.usize, None, span), | |
2736 | hir::ArrayLen::Body(constant) => { | |
487cf647 | 2737 | ty::Const::from_anon_const(tcx, constant.def_id) |
a2a8927a XL |
2738 | } |
2739 | }; | |
2740 | ||
c295e0f8 | 2741 | let array_ty = tcx.mk_ty(ty::Array(self.ast_ty_to_ty(ty), length)); |
ea8adc8c | 2742 | self.normalize_ty(ast_ty.span, array_ty) |
1a4d82fc | 2743 | } |
cdc7bbd5 | 2744 | hir::TyKind::Typeof(ref e) => { |
487cf647 | 2745 | let ty_erased = tcx.type_of(e.def_id); |
f2b60f7d FG |
2746 | let ty = tcx.fold_regions(ty_erased, |r, _| { |
2747 | if r.is_erased() { tcx.lifetimes.re_static } else { r } | |
2748 | }); | |
04454e1e FG |
2749 | let span = ast_ty.span; |
2750 | tcx.sess.emit_err(TypeofReservedKeywordUsed { | |
2751 | span, | |
2752 | ty, | |
2753 | opt_sugg: Some((span, Applicability::MachineApplicable)) | |
064997fb | 2754 | .filter(|_| ty.is_suggestable(tcx, false)), |
04454e1e FG |
2755 | }); |
2756 | ||
2757 | ty | |
a7813a04 | 2758 | } |
8faf50e0 | 2759 | hir::TyKind::Infer => { |
b7449926 | 2760 | // Infer also appears as the type of arguments or return |
94222f64 | 2761 | // values in an ExprKind::Closure, or as |
a7813a04 XL |
2762 | // the type of local variables. Both of these cases are |
2763 | // handled specially and will not descend into this routine. | |
dc9dc135 | 2764 | self.ty_infer(None, ast_ty.span) |
cc61c64b | 2765 | } |
f035d41b | 2766 | hir::TyKind::Err => tcx.ty_error(), |
a7813a04 | 2767 | }; |
1a4d82fc | 2768 | |
ea8adc8c | 2769 | self.record_ty(ast_ty.hir_id, result_ty, ast_ty.span); |
a7813a04 | 2770 | result_ty |
1a4d82fc | 2771 | } |
1a4d82fc | 2772 | |
f2b60f7d | 2773 | #[instrument(level = "debug", skip(self), ret)] |
cdc7bbd5 | 2774 | fn impl_trait_ty_to_ty( |
94b46f34 XL |
2775 | &self, |
2776 | def_id: DefId, | |
dfeec247 | 2777 | lifetimes: &[hir::GenericArg<'_>], |
923072b8 | 2778 | origin: OpaqueTyOrigin, |
f2b60f7d | 2779 | in_trait: bool, |
94b46f34 | 2780 | ) -> Ty<'tcx> { |
ff7c6d11 XL |
2781 | debug!("impl_trait_ty_to_ty(def_id={:?}, lifetimes={:?})", def_id, lifetimes); |
2782 | let tcx = self.tcx(); | |
94b46f34 | 2783 | |
ff7c6d11 XL |
2784 | let generics = tcx.generics_of(def_id); |
2785 | ||
ff7c6d11 | 2786 | debug!("impl_trait_ty_to_ty: generics={:?}", generics); |
532ac7d7 | 2787 | let substs = InternalSubsts::for_item(tcx, def_id, |param, _| { |
94b46f34 XL |
2788 | if let Some(i) = (param.index as usize).checked_sub(generics.parent_count) { |
2789 | // Our own parameters are the resolved lifetimes. | |
487cf647 FG |
2790 | let GenericParamDefKind::Lifetime { .. } = param.kind else { bug!() }; |
2791 | let hir::GenericArg::Lifetime(lifetime) = &lifetimes[i] else { bug!() }; | |
2792 | self.ast_region_to_region(lifetime, None).into() | |
94b46f34 | 2793 | } else { |
487cf647 | 2794 | tcx.mk_param_from_def(param) |
ff7c6d11 | 2795 | } |
94b46f34 | 2796 | }); |
dc9dc135 | 2797 | debug!("impl_trait_ty_to_ty: substs={:?}", substs); |
ff7c6d11 | 2798 | |
f2b60f7d | 2799 | if in_trait { tcx.mk_projection(def_id, substs) } else { tcx.mk_opaque(def_id, substs) } |
ff7c6d11 XL |
2800 | } |
2801 | ||
dfeec247 | 2802 | pub fn ty_of_arg(&self, ty: &hir::Ty<'_>, expected_ty: Option<Ty<'tcx>>) -> Ty<'tcx> { |
e74abb32 | 2803 | match ty.kind { |
8faf50e0 | 2804 | hir::TyKind::Infer if expected_ty.is_some() => { |
ea8adc8c XL |
2805 | self.record_ty(ty.hir_id, expected_ty.unwrap(), ty.span); |
2806 | expected_ty.unwrap() | |
2807 | } | |
32a655c1 | 2808 | _ => self.ast_ty_to_ty(ty), |
a7813a04 XL |
2809 | } |
2810 | } | |
1a4d82fc | 2811 | |
2b03887a | 2812 | #[instrument(level = "debug", skip(self, hir_id, unsafety, abi, decl, generics, hir_ty), ret)] |
dfeec247 XL |
2813 | pub fn ty_of_fn( |
2814 | &self, | |
cdc7bbd5 | 2815 | hir_id: hir::HirId, |
dfeec247 XL |
2816 | unsafety: hir::Unsafety, |
2817 | abi: abi::Abi, | |
2818 | decl: &hir::FnDecl<'_>, | |
04454e1e | 2819 | generics: Option<&hir::Generics<'_>>, |
6a06907d | 2820 | hir_ty: Option<&hir::Ty<'_>>, |
dfeec247 | 2821 | ) -> ty::PolyFnSig<'tcx> { |
ea8adc8c | 2822 | let tcx = self.tcx(); |
cdc7bbd5 XL |
2823 | let bound_vars = tcx.late_bound_vars(hir_id); |
2824 | debug!(?bound_vars); | |
1a4d82fc | 2825 | |
74b04a01 | 2826 | // We proactively collect all the inferred type params to emit a single error per fn def. |
5099ac24 | 2827 | let mut visitor = HirPlaceholderCollector::default(); |
04454e1e FG |
2828 | let mut infer_replacements = vec![]; |
2829 | ||
2830 | if let Some(generics) = generics { | |
2831 | walk_generics(&mut visitor, generics); | |
dfeec247 | 2832 | } |
74b04a01 | 2833 | |
04454e1e FG |
2834 | let input_tys: Vec<_> = decl |
2835 | .inputs | |
2836 | .iter() | |
2837 | .enumerate() | |
2838 | .map(|(i, a)| { | |
2839 | if let hir::TyKind::Infer = a.kind && !self.allow_ty_infer() { | |
2840 | if let Some(suggested_ty) = | |
2841 | self.suggest_trait_fn_ty_for_impl_fn_infer(hir_id, Some(i)) | |
2842 | { | |
2843 | infer_replacements.push((a.span, suggested_ty.to_string())); | |
2844 | return suggested_ty; | |
2845 | } | |
2846 | } | |
2847 | ||
2848 | // Only visit the type looking for `_` if we didn't fix the type above | |
2849 | visitor.visit_ty(a); | |
2850 | self.ty_of_arg(a, None) | |
2851 | }) | |
2852 | .collect(); | |
2853 | ||
a7813a04 | 2854 | let output_ty = match decl.output { |
c295e0f8 | 2855 | hir::FnRetTy::Return(output) => { |
04454e1e FG |
2856 | if let hir::TyKind::Infer = output.kind |
2857 | && !self.allow_ty_infer() | |
2858 | && let Some(suggested_ty) = | |
2859 | self.suggest_trait_fn_ty_for_impl_fn_infer(hir_id, None) | |
2860 | { | |
2861 | infer_replacements.push((output.span, suggested_ty.to_string())); | |
2862 | suggested_ty | |
2863 | } else { | |
2864 | visitor.visit_ty(output); | |
2865 | self.ast_ty_to_ty(output) | |
2866 | } | |
dfeec247 | 2867 | } |
74b04a01 | 2868 | hir::FnRetTy::DefaultReturn(..) => tcx.mk_unit(), |
a7813a04 | 2869 | }; |
1a4d82fc | 2870 | |
2b03887a | 2871 | debug!(?output_ty); |
9e0c209e | 2872 | |
04454e1e | 2873 | let fn_ty = tcx.mk_fn_sig(input_tys.into_iter(), output_ty, decl.c_variadic, unsafety, abi); |
cdc7bbd5 | 2874 | let bare_fn_ty = ty::Binder::bind_with_vars(fn_ty, bound_vars); |
dfeec247 | 2875 | |
04454e1e | 2876 | if !self.allow_ty_infer() && !(visitor.0.is_empty() && infer_replacements.is_empty()) { |
dfeec247 XL |
2877 | // We always collect the spans for placeholder types when evaluating `fn`s, but we |
2878 | // only want to emit an error complaining about them if infer types (`_`) are not | |
ba9703b0 XL |
2879 | // allowed. `allow_ty_infer` gates this behavior. We check for the presence of |
2880 | // `ident_span` to not emit an error twice when we have `fn foo(_: fn() -> _)`. | |
6a06907d | 2881 | |
04454e1e | 2882 | let mut diag = crate::collect::placeholder_type_error_diag( |
dfeec247 | 2883 | tcx, |
04454e1e | 2884 | generics, |
dfeec247 | 2885 | visitor.0, |
04454e1e | 2886 | infer_replacements.iter().map(|(s, _)| *s).collect(), |
ba9703b0 | 2887 | true, |
6a06907d | 2888 | hir_ty, |
136023e0 | 2889 | "function", |
dfeec247 | 2890 | ); |
04454e1e FG |
2891 | |
2892 | if !infer_replacements.is_empty() { | |
f2b60f7d FG |
2893 | diag.multipart_suggestion( |
2894 | &format!( | |
04454e1e FG |
2895 | "try replacing `_` with the type{} in the corresponding trait method signature", |
2896 | rustc_errors::pluralize!(infer_replacements.len()), | |
f2b60f7d FG |
2897 | ), |
2898 | infer_replacements, | |
2899 | Applicability::MachineApplicable, | |
2900 | ); | |
04454e1e FG |
2901 | } |
2902 | ||
2903 | diag.emit(); | |
dfeec247 | 2904 | } |
ea8adc8c XL |
2905 | |
2906 | // Find any late-bound regions declared in return type that do | |
0bf4aa26 | 2907 | // not appear in the arguments. These are not well-formed. |
ea8adc8c XL |
2908 | // |
2909 | // Example: | |
2910 | // for<'a> fn() -> &'a str <-- 'a is bad | |
2911 | // for<'a> fn(&'a String) -> &'a str <-- 'a is ok | |
2912 | let inputs = bare_fn_ty.inputs(); | |
dfeec247 XL |
2913 | let late_bound_in_args = |
2914 | tcx.collect_constrained_late_bound_regions(&inputs.map_bound(|i| i.to_owned())); | |
ea8adc8c XL |
2915 | let output = bare_fn_ty.output(); |
2916 | let late_bound_in_ret = tcx.collect_referenced_late_bound_regions(&output); | |
3dfed10e XL |
2917 | |
2918 | self.validate_late_bound_regions(late_bound_in_args, late_bound_in_ret, |br_name| { | |
2919 | struct_span_err!( | |
dfeec247 XL |
2920 | tcx.sess, |
2921 | decl.output.span(), | |
2922 | E0581, | |
3dfed10e XL |
2923 | "return type references {}, which is not constrained by the fn input types", |
2924 | br_name | |
2925 | ) | |
2926 | }); | |
2927 | ||
2928 | bare_fn_ty | |
2929 | } | |
2930 | ||
04454e1e FG |
2931 | /// Given a fn_hir_id for a impl function, suggest the type that is found on the |
2932 | /// corresponding function in the trait that the impl implements, if it exists. | |
2933 | /// If arg_idx is Some, then it corresponds to an input type index, otherwise it | |
2934 | /// corresponds to the return type. | |
2935 | fn suggest_trait_fn_ty_for_impl_fn_infer( | |
2936 | &self, | |
2937 | fn_hir_id: hir::HirId, | |
2938 | arg_idx: Option<usize>, | |
2939 | ) -> Option<Ty<'tcx>> { | |
2940 | let tcx = self.tcx(); | |
2941 | let hir = tcx.hir(); | |
2942 | ||
2943 | let hir::Node::ImplItem(hir::ImplItem { kind: hir::ImplItemKind::Fn(..), ident, .. }) = | |
2944 | hir.get(fn_hir_id) else { return None }; | |
2945 | let hir::Node::Item(hir::Item { kind: hir::ItemKind::Impl(i), .. }) = | |
2946 | hir.get(hir.get_parent_node(fn_hir_id)) else { bug!("ImplItem should have Impl parent") }; | |
2947 | ||
2b03887a FG |
2948 | let trait_ref = self.instantiate_mono_trait_ref( |
2949 | i.of_trait.as_ref()?, | |
2950 | self.ast_ty_to_ty(i.self_ty), | |
2951 | ty::BoundConstness::NotConst, | |
2952 | ); | |
04454e1e FG |
2953 | |
2954 | let assoc = tcx.associated_items(trait_ref.def_id).find_by_name_and_kind( | |
2955 | tcx, | |
2956 | *ident, | |
2957 | ty::AssocKind::Fn, | |
2958 | trait_ref.def_id, | |
2959 | )?; | |
2960 | ||
2961 | let fn_sig = tcx.bound_fn_sig(assoc.def_id).subst( | |
2962 | tcx, | |
2963 | trait_ref.substs.extend_to(tcx, assoc.def_id, |param, _| tcx.mk_param_from_def(param)), | |
2964 | ); | |
2965 | ||
2966 | let ty = if let Some(arg_idx) = arg_idx { fn_sig.input(arg_idx) } else { fn_sig.output() }; | |
2967 | ||
2968 | Some(tcx.liberate_late_bound_regions(fn_hir_id.expect_owner().to_def_id(), ty)) | |
2969 | } | |
2970 | ||
487cf647 | 2971 | #[instrument(level = "trace", skip(self, generate_err))] |
3dfed10e XL |
2972 | fn validate_late_bound_regions( |
2973 | &self, | |
fc512014 XL |
2974 | constrained_regions: FxHashSet<ty::BoundRegionKind>, |
2975 | referenced_regions: FxHashSet<ty::BoundRegionKind>, | |
5e7ed085 | 2976 | generate_err: impl Fn(&str) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>, |
3dfed10e XL |
2977 | ) { |
2978 | for br in referenced_regions.difference(&constrained_regions) { | |
2979 | let br_name = match *br { | |
487cf647 | 2980 | ty::BrNamed(_, kw::UnderscoreLifetime) | ty::BrAnon(..) | ty::BrEnv => { |
923072b8 FG |
2981 | "an anonymous lifetime".to_string() |
2982 | } | |
3dfed10e | 2983 | ty::BrNamed(_, name) => format!("lifetime `{}`", name), |
3dfed10e XL |
2984 | }; |
2985 | ||
2986 | let mut err = generate_err(&br_name); | |
2987 | ||
487cf647 | 2988 | if let ty::BrNamed(_, kw::UnderscoreLifetime) | ty::BrAnon(..) = *br { |
2c00a5a8 XL |
2989 | // The only way for an anonymous lifetime to wind up |
2990 | // in the return type but **also** be unconstrained is | |
2991 | // if it only appears in "associated types" in the | |
3dfed10e | 2992 | // input. See #47511 and #62200 for examples. In this case, |
2c00a5a8 XL |
2993 | // though we can easily give a hint that ought to be |
2994 | // relevant. | |
dfeec247 | 2995 | err.note( |
f2b60f7d | 2996 | "lifetimes appearing in an associated or opaque type are not considered constrained", |
dfeec247 | 2997 | ); |
f2b60f7d | 2998 | err.note("consider introducing a named lifetime parameter"); |
2c00a5a8 | 2999 | } |
3dfed10e | 3000 | |
2c00a5a8 | 3001 | err.emit(); |
ea8adc8c | 3002 | } |
a7813a04 | 3003 | } |
1a4d82fc | 3004 | |
a7813a04 XL |
3005 | /// Given the bounds on an object, determines what single region bound (if any) we can |
3006 | /// use to summarize this type. The basic idea is that we will use the bound the user | |
3007 | /// provided, if they provided one, and otherwise search the supertypes of trait bounds | |
3008 | /// for region bounds. It may be that we can derive no bound at all, in which case | |
3009 | /// we return `None`. | |
dfeec247 XL |
3010 | fn compute_object_lifetime_bound( |
3011 | &self, | |
a7813a04 | 3012 | span: Span, |
487cf647 | 3013 | existential_predicates: &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>, |
dfeec247 | 3014 | ) -> Option<ty::Region<'tcx>> // if None, use the default |
a7813a04 XL |
3015 | { |
3016 | let tcx = self.tcx(); | |
85aaf69f | 3017 | |
dfeec247 | 3018 | debug!("compute_opt_region_bound(existential_predicates={:?})", existential_predicates); |
1a4d82fc | 3019 | |
a7813a04 XL |
3020 | // No explicit region bound specified. Therefore, examine trait |
3021 | // bounds and see if we can derive region bounds from those. | |
dfeec247 | 3022 | let derived_region_bounds = object_region_bounds(tcx, existential_predicates); |
1a4d82fc | 3023 | |
a7813a04 XL |
3024 | // If there are no derived region bounds, then report back that we |
3025 | // can find no region bound. The caller will use the default. | |
3026 | if derived_region_bounds.is_empty() { | |
3027 | return None; | |
3028 | } | |
1a4d82fc | 3029 | |
a7813a04 XL |
3030 | // If any of the derived region bounds are 'static, that is always |
3031 | // the best choice. | |
5099ac24 | 3032 | if derived_region_bounds.iter().any(|r| r.is_static()) { |
48663c56 | 3033 | return Some(tcx.lifetimes.re_static); |
a7813a04 | 3034 | } |
1a4d82fc | 3035 | |
a7813a04 XL |
3036 | // Determine whether there is exactly one unique region in the set |
3037 | // of derived region bounds. If so, use that. Otherwise, report an | |
3038 | // error. | |
3039 | let r = derived_region_bounds[0]; | |
3040 | if derived_region_bounds[1..].iter().any(|r1| r != *r1) { | |
1b1a35ee | 3041 | tcx.sess.emit_err(AmbiguousLifetimeBound { span }); |
a7813a04 | 3042 | } |
ba9703b0 | 3043 | Some(r) |
1a4d82fc | 3044 | } |
a2a8927a | 3045 | |
064997fb | 3046 | /// Make sure that we are in the condition to suggest the blanket implementation. |
f2b60f7d | 3047 | fn maybe_lint_blanket_trait_impl(&self, self_ty: &hir::Ty<'_>, diag: &mut Diagnostic) { |
064997fb | 3048 | let tcx = self.tcx(); |
2b03887a | 3049 | let parent_id = tcx.hir().get_parent_item(self_ty.hir_id).def_id; |
064997fb FG |
3050 | if let hir::Node::Item(hir::Item { |
3051 | kind: | |
3052 | hir::ItemKind::Impl(hir::Impl { | |
3053 | self_ty: impl_self_ty, of_trait: Some(of_trait_ref), generics, .. | |
3054 | }), | |
3055 | .. | |
3056 | }) = tcx.hir().get_by_def_id(parent_id) && self_ty.hir_id == impl_self_ty.hir_id | |
3057 | { | |
3058 | if !of_trait_ref.trait_def_id().map_or(false, |def_id| def_id.is_local()) { | |
3059 | return; | |
3060 | } | |
3061 | let of_trait_span = of_trait_ref.path.span; | |
3062 | // make sure that we are not calling unwrap to abort during the compilation | |
3063 | let Ok(impl_trait_name) = tcx.sess.source_map().span_to_snippet(self_ty.span) else { return; }; | |
3064 | let Ok(of_trait_name) = tcx.sess.source_map().span_to_snippet(of_trait_span) else { return; }; | |
3065 | // check if the trait has generics, to make a correct suggestion | |
3066 | let param_name = generics.params.next_type_param_name(None); | |
3067 | ||
3068 | let add_generic_sugg = if let Some(span) = generics.span_for_param_suggestion() { | |
3069 | (span, format!(", {}: {}", param_name, impl_trait_name)) | |
3070 | } else { | |
3071 | (generics.span, format!("<{}: {}>", param_name, impl_trait_name)) | |
3072 | }; | |
3073 | diag.multipart_suggestion( | |
3074 | format!("alternatively use a blanket \ | |
3075 | implementation to implement `{of_trait_name}` for \ | |
3076 | all types that also implement `{impl_trait_name}`"), | |
3077 | vec![ | |
3078 | (self_ty.span, param_name), | |
3079 | add_generic_sugg, | |
3080 | ], | |
3081 | Applicability::MaybeIncorrect, | |
3082 | ); | |
3083 | } | |
3084 | } | |
3085 | ||
a2a8927a XL |
3086 | fn maybe_lint_bare_trait(&self, self_ty: &hir::Ty<'_>, in_path: bool) { |
3087 | let tcx = self.tcx(); | |
3088 | if let hir::TyKind::TraitObject([poly_trait_ref, ..], _, TraitObjectSyntax::None) = | |
3089 | self_ty.kind | |
3090 | { | |
3091 | let needs_bracket = in_path | |
3092 | && !tcx | |
3093 | .sess | |
3094 | .source_map() | |
3095 | .span_to_prev_source(self_ty.span) | |
3096 | .ok() | |
3097 | .map_or(false, |s| s.trim_end().ends_with('<')); | |
3098 | ||
3099 | let is_global = poly_trait_ref.trait_ref.path.is_global(); | |
2b03887a FG |
3100 | |
3101 | let mut sugg = Vec::from_iter([( | |
3102 | self_ty.span.shrink_to_lo(), | |
3103 | format!( | |
3104 | "{}dyn {}", | |
3105 | if needs_bracket { "<" } else { "" }, | |
3106 | if is_global { "(" } else { "" }, | |
a2a8927a | 3107 | ), |
2b03887a FG |
3108 | )]); |
3109 | ||
3110 | if is_global || needs_bracket { | |
3111 | sugg.push(( | |
a2a8927a XL |
3112 | self_ty.span.shrink_to_hi(), |
3113 | format!( | |
3114 | "{}{}", | |
3115 | if is_global { ")" } else { "" }, | |
3116 | if needs_bracket { ">" } else { "" }, | |
3117 | ), | |
2b03887a FG |
3118 | )); |
3119 | } | |
3120 | ||
a2a8927a XL |
3121 | if self_ty.span.edition() >= Edition::Edition2021 { |
3122 | let msg = "trait objects must include the `dyn` keyword"; | |
3123 | let label = "add `dyn` keyword before this trait"; | |
064997fb FG |
3124 | let mut diag = |
3125 | rustc_errors::struct_span_err!(tcx.sess, self_ty.span, E0782, "{}", msg); | |
3126 | diag.multipart_suggestion_verbose(label, sugg, Applicability::MachineApplicable); | |
3127 | // check if the impl trait that we are considering is a impl of a local trait | |
3128 | self.maybe_lint_blanket_trait_impl(&self_ty, &mut diag); | |
3129 | diag.emit(); | |
a2a8927a XL |
3130 | } else { |
3131 | let msg = "trait objects without an explicit `dyn` are deprecated"; | |
3132 | tcx.struct_span_lint_hir( | |
3133 | BARE_TRAIT_OBJECTS, | |
3134 | self_ty.hir_id, | |
3135 | self_ty.span, | |
2b03887a | 3136 | msg, |
a2a8927a | 3137 | |lint| { |
2b03887a | 3138 | lint.multipart_suggestion_verbose( |
064997fb FG |
3139 | "use `dyn`", |
3140 | sugg, | |
3141 | Applicability::MachineApplicable, | |
3142 | ); | |
2b03887a FG |
3143 | self.maybe_lint_blanket_trait_impl(&self_ty, lint); |
3144 | lint | |
a2a8927a XL |
3145 | }, |
3146 | ); | |
3147 | } | |
3148 | } | |
3149 | } | |
1a4d82fc | 3150 | } |