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Commit | Line | Data |
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0731742a XL |
1 | //! Conversion from AST representation of types to the `ty.rs` representation. |
2 | //! The main routine here is `ast_ty_to_ty()`; each use is parameterized by an | |
3 | //! instance of `AstConv`. | |
1a4d82fc | 4 | |
3dfed10e XL |
5 | mod errors; |
6 | mod generics; | |
dfeec247 | 7 | |
3dfed10e | 8 | use crate::bounds::Bounds; |
5099ac24 | 9 | use crate::collect::HirPlaceholderCollector; |
1b1a35ee XL |
10 | use crate::errors::{ |
11 | AmbiguousLifetimeBound, MultipleRelaxedDefaultBounds, TraitObjectDeclaredWithNoTraits, | |
12 | TypeofReservedKeywordUsed, ValueOfAssociatedStructAlreadySpecified, | |
13 | }; | |
9fa01778 | 14 | use crate::middle::resolve_lifetime as rl; |
dfeec247 | 15 | use crate::require_c_abi_if_c_variadic; |
a2a8927a | 16 | use rustc_ast::TraitObjectSyntax; |
dfeec247 | 17 | use rustc_data_structures::fx::{FxHashMap, FxHashSet}; |
5e7ed085 | 18 | use rustc_errors::{ |
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 _}; |
3dfed10e | 26 | use rustc_hir::lang_items::LangItem; |
923072b8 FG |
27 | use rustc_hir::{GenericArg, GenericArgs, OpaqueTyOrigin}; |
28 | use rustc_middle::middle::stability::AllowUnstable; | |
94222f64 | 29 | use rustc_middle::ty::subst::{self, GenericArgKind, InternalSubsts, Subst, SubstsRef}; |
f2b60f7d | 30 | use rustc_middle::ty::DynKind; |
3dfed10e | 31 | use rustc_middle::ty::GenericParamDefKind; |
923072b8 | 32 | use rustc_middle::ty::{ |
064997fb | 33 | self, Const, DefIdTree, EarlyBinder, IsSuggestable, Ty, TyCtxt, TypeVisitable, |
923072b8 | 34 | }; |
a2a8927a XL |
35 | use rustc_session::lint::builtin::{AMBIGUOUS_ASSOCIATED_ITEMS, BARE_TRAIT_OBJECTS}; |
36 | use rustc_span::edition::Edition; | |
fc512014 | 37 | use rustc_span::lev_distance::find_best_match_for_name; |
923072b8 | 38 | use rustc_span::symbol::{kw, Ident, Symbol}; |
f2b60f7d | 39 | use rustc_span::Span; |
83c7162d | 40 | use rustc_target::spec::abi; |
ba9703b0 XL |
41 | use rustc_trait_selection::traits; |
42 | use rustc_trait_selection::traits::astconv_object_safety_violations; | |
064997fb FG |
43 | use rustc_trait_selection::traits::error_reporting::{ |
44 | report_object_safety_error, suggestions::NextTypeParamName, | |
45 | }; | |
ba9703b0 | 46 | use rustc_trait_selection::traits::wf::object_region_bounds; |
0731742a | 47 | |
f2b60f7d | 48 | use smallvec::{smallvec, SmallVec}; |
0731742a | 49 | use std::collections::BTreeSet; |
0731742a XL |
50 | use std::slice; |
51 | ||
0731742a XL |
52 | #[derive(Debug)] |
53 | pub struct PathSeg(pub DefId, pub usize); | |
e9174d1e | 54 | |
dc9dc135 XL |
55 | pub trait AstConv<'tcx> { |
56 | fn tcx<'a>(&'a self) -> TyCtxt<'tcx>; | |
1a4d82fc | 57 | |
60c5eb7d XL |
58 | fn item_def_id(&self) -> Option<DefId>; |
59 | ||
6a06907d XL |
60 | /// Returns predicates in scope of the form `X: Foo<T>`, where `X` |
61 | /// is a type parameter `X` with the given id `def_id` and T | |
62 | /// matches `assoc_name`. This is a subset of the full set of | |
63 | /// predicates. | |
416331ca XL |
64 | /// |
65 | /// This is used for one specific purpose: resolving "short-hand" | |
66 | /// associated type references like `T::Item`. In principle, we | |
67 | /// would do that by first getting the full set of predicates in | |
68 | /// scope and then filtering down to find those that apply to `T`, | |
69 | /// but this can lead to cycle errors. The problem is that we have | |
70 | /// to do this resolution *in order to create the predicates in | |
71 | /// the first place*. Hence, we have this "special pass". | |
6a06907d XL |
72 | fn get_type_parameter_bounds( |
73 | &self, | |
74 | span: Span, | |
75 | def_id: DefId, | |
76 | assoc_name: Ident, | |
77 | ) -> ty::GenericPredicates<'tcx>; | |
c34b1796 | 78 | |
dc9dc135 | 79 | /// Returns the lifetime to use when a lifetime is omitted (and not elided). |
dfeec247 XL |
80 | fn re_infer(&self, param: Option<&ty::GenericParamDef>, span: Span) |
81 | -> Option<ty::Region<'tcx>>; | |
32a655c1 | 82 | |
dc9dc135 XL |
83 | /// Returns the type to use when a type is omitted. |
84 | fn ty_infer(&self, param: Option<&ty::GenericParamDef>, span: Span) -> Ty<'tcx>; | |
9e0c209e | 85 | |
dfeec247 XL |
86 | /// Returns `true` if `_` is allowed in type signatures in the current context. |
87 | fn allow_ty_infer(&self) -> bool; | |
88 | ||
dc9dc135 XL |
89 | /// Returns the const to use when a const is omitted. |
90 | fn ct_infer( | |
91 | &self, | |
92 | ty: Ty<'tcx>, | |
93 | param: Option<&ty::GenericParamDef>, | |
94 | span: Span, | |
5099ac24 | 95 | ) -> Const<'tcx>; |
1a4d82fc JJ |
96 | |
97 | /// Projecting an associated type from a (potentially) | |
98 | /// higher-ranked trait reference is more complicated, because of | |
99 | /// the possibility of late-bound regions appearing in the | |
100 | /// associated type binding. This is not legal in function | |
101 | /// signatures for that reason. In a function body, we can always | |
102 | /// handle it because we can use inference variables to remove the | |
103 | /// late-bound regions. | |
dfeec247 XL |
104 | fn projected_ty_from_poly_trait_ref( |
105 | &self, | |
106 | span: Span, | |
107 | item_def_id: DefId, | |
108 | item_segment: &hir::PathSegment<'_>, | |
109 | poly_trait_ref: ty::PolyTraitRef<'tcx>, | |
110 | ) -> Ty<'tcx>; | |
1a4d82fc | 111 | |
8bb4bdeb XL |
112 | /// Normalize an associated type coming from the user. |
113 | fn normalize_ty(&self, span: Span, ty: Ty<'tcx>) -> Ty<'tcx>; | |
a7813a04 XL |
114 | |
115 | /// Invoked when we encounter an error from some prior pass | |
0731742a | 116 | /// (e.g., resolve) that is translated into a ty-error. This is |
a7813a04 XL |
117 | /// used to help suppress derived errors typeck might otherwise |
118 | /// report. | |
119 | fn set_tainted_by_errors(&self); | |
ea8adc8c XL |
120 | |
121 | fn record_ty(&self, hir_id: hir::HirId, ty: Ty<'tcx>, span: Span); | |
a7813a04 XL |
122 | } |
123 | ||
5869c6ff | 124 | #[derive(Debug)] |
dc9dc135 | 125 | struct ConvertedBinding<'a, 'tcx> { |
17df50a5 | 126 | hir_id: hir::HirId, |
f9f354fc | 127 | item_name: Ident, |
dc9dc135 | 128 | kind: ConvertedBindingKind<'a, 'tcx>, |
5869c6ff | 129 | gen_args: &'a GenericArgs<'a>, |
a7813a04 | 130 | span: Span, |
1a4d82fc JJ |
131 | } |
132 | ||
5869c6ff | 133 | #[derive(Debug)] |
dc9dc135 | 134 | enum ConvertedBindingKind<'a, 'tcx> { |
5099ac24 | 135 | Equality(ty::Term<'tcx>), |
dfeec247 | 136 | Constraint(&'a [hir::GenericBound<'a>]), |
dc9dc135 XL |
137 | } |
138 | ||
f9f354fc XL |
139 | /// New-typed boolean indicating whether explicit late-bound lifetimes |
140 | /// are present in a set of generic arguments. | |
141 | /// | |
142 | /// For example if we have some method `fn f<'a>(&'a self)` implemented | |
143 | /// for some type `T`, although `f` is generic in the lifetime `'a`, `'a` | |
144 | /// is late-bound so should not be provided explicitly. Thus, if `f` is | |
145 | /// instantiated with some generic arguments providing `'a` explicitly, | |
146 | /// we taint those arguments with `ExplicitLateBound::Yes` so that we | |
147 | /// can provide an appropriate diagnostic later. | |
f2b60f7d | 148 | #[derive(Copy, Clone, PartialEq, Debug)] |
f9f354fc XL |
149 | pub enum ExplicitLateBound { |
150 | Yes, | |
151 | No, | |
152 | } | |
153 | ||
5869c6ff XL |
154 | #[derive(Copy, Clone, PartialEq)] |
155 | pub enum IsMethodCall { | |
156 | Yes, | |
157 | No, | |
158 | } | |
159 | ||
3dfed10e XL |
160 | /// Denotes the "position" of a generic argument, indicating if it is a generic type, |
161 | /// generic function or generic method call. | |
f9f354fc | 162 | #[derive(Copy, Clone, PartialEq)] |
3dfed10e | 163 | pub(crate) enum GenericArgPosition { |
b7449926 | 164 | Type, |
0731742a | 165 | Value, // e.g., functions |
b7449926 | 166 | MethodCall, |
94b46f34 XL |
167 | } |
168 | ||
74b04a01 XL |
169 | /// A marker denoting that the generic arguments that were |
170 | /// provided did not match the respective generic parameters. | |
f2b60f7d | 171 | #[derive(Clone, Default, Debug)] |
74b04a01 XL |
172 | pub struct GenericArgCountMismatch { |
173 | /// Indicates whether a fatal error was reported (`Some`), or just a lint (`None`). | |
5e7ed085 | 174 | pub reported: Option<ErrorGuaranteed>, |
74b04a01 XL |
175 | /// A list of spans of arguments provided that were not valid. |
176 | pub invalid_args: Vec<Span>, | |
177 | } | |
178 | ||
f9f354fc XL |
179 | /// Decorates the result of a generic argument count mismatch |
180 | /// check with whether explicit late bounds were provided. | |
f2b60f7d | 181 | #[derive(Clone, Debug)] |
f9f354fc XL |
182 | pub struct GenericArgCountResult { |
183 | pub explicit_late_bound: ExplicitLateBound, | |
184 | pub correct: Result<(), GenericArgCountMismatch>, | |
185 | } | |
186 | ||
fc512014 XL |
187 | pub trait CreateSubstsForGenericArgsCtxt<'a, 'tcx> { |
188 | fn args_for_def_id(&mut self, def_id: DefId) -> (Option<&'a GenericArgs<'a>>, bool); | |
189 | ||
190 | fn provided_kind( | |
191 | &mut self, | |
192 | param: &ty::GenericParamDef, | |
193 | arg: &GenericArg<'_>, | |
194 | ) -> subst::GenericArg<'tcx>; | |
195 | ||
196 | fn inferred_kind( | |
197 | &mut self, | |
198 | substs: Option<&[subst::GenericArg<'tcx>]>, | |
199 | param: &ty::GenericParamDef, | |
200 | infer_args: bool, | |
201 | ) -> subst::GenericArg<'tcx>; | |
202 | } | |
203 | ||
dc9dc135 | 204 | impl<'o, 'tcx> dyn AstConv<'tcx> + 'o { |
f2b60f7d | 205 | #[instrument(level = "debug", skip(self), ret)] |
dfeec247 XL |
206 | pub fn ast_region_to_region( |
207 | &self, | |
32a655c1 | 208 | lifetime: &hir::Lifetime, |
dfeec247 XL |
209 | def: Option<&ty::GenericParamDef>, |
210 | ) -> ty::Region<'tcx> { | |
32a655c1 | 211 | let tcx = self.tcx(); |
3dfed10e | 212 | let lifetime_name = |def_id| tcx.hir().name(tcx.hir().local_def_id_to_hir_id(def_id)); |
ea8adc8c | 213 | |
f2b60f7d | 214 | match tcx.named_region(lifetime.hir_id) { |
dfeec247 | 215 | Some(rl::Region::Static) => tcx.lifetimes.re_static, |
32a655c1 | 216 | |
5e7ed085 | 217 | Some(rl::Region::LateBound(debruijn, index, def_id)) => { |
cdc7bbd5 XL |
218 | let name = lifetime_name(def_id.expect_local()); |
219 | let br = ty::BoundRegion { | |
220 | var: ty::BoundVar::from_u32(index), | |
221 | kind: ty::BrNamed(def_id, name), | |
222 | }; | |
fc512014 | 223 | tcx.mk_region(ty::ReLateBound(debruijn, br)) |
32a655c1 SL |
224 | } |
225 | ||
f2b60f7d FG |
226 | Some(rl::Region::EarlyBound(def_id)) => { |
227 | let name = tcx.hir().ty_param_name(def_id.expect_local()); | |
228 | let item_def_id = tcx.hir().ty_param_owner(def_id.expect_local()); | |
229 | let generics = tcx.generics_of(item_def_id); | |
230 | let index = generics.param_def_id_to_index[&def_id]; | |
231 | tcx.mk_region(ty::ReEarlyBound(ty::EarlyBoundRegion { def_id, index, name })) | |
32a655c1 SL |
232 | } |
233 | ||
ea8adc8c | 234 | Some(rl::Region::Free(scope, id)) => { |
f9f354fc | 235 | let name = lifetime_name(id.expect_local()); |
32a655c1 | 236 | tcx.mk_region(ty::ReFree(ty::FreeRegion { |
7cac9316 | 237 | scope, |
dfeec247 | 238 | bound_region: ty::BrNamed(id, name), |
32a655c1 | 239 | })) |
5bcae85e | 240 | |
0bf4aa26 | 241 | // (*) -- not late-bound, won't change |
32a655c1 | 242 | } |
5bcae85e | 243 | |
32a655c1 | 244 | None => { |
dfeec247 | 245 | self.re_infer(def, lifetime.span).unwrap_or_else(|| { |
cdc7bbd5 XL |
246 | debug!(?lifetime, "unelided lifetime in signature"); |
247 | ||
dfeec247 XL |
248 | // This indicates an illegal lifetime |
249 | // elision. `resolve_lifetime` should have | |
250 | // reported an error in this case -- but if | |
251 | // not, let's error out. | |
252 | tcx.sess.delay_span_bug(lifetime.span, "unelided lifetime in signature"); | |
253 | ||
254 | // Supply some dummy value. We don't have an | |
255 | // `re_error`, annoyingly, so use `'static`. | |
256 | tcx.lifetimes.re_static | |
257 | }) | |
32a655c1 | 258 | } |
f2b60f7d | 259 | } |
a7813a04 | 260 | } |
1a4d82fc | 261 | |
a7813a04 XL |
262 | /// Given a path `path` that refers to an item `I` with the declared generics `decl_generics`, |
263 | /// returns an appropriate set of substitutions for this particular reference to `I`. | |
dfeec247 XL |
264 | pub fn ast_path_substs_for_ty( |
265 | &self, | |
a7813a04 | 266 | span: Span, |
9e0c209e | 267 | def_id: DefId, |
dfeec247 XL |
268 | item_segment: &hir::PathSegment<'_>, |
269 | ) -> SubstsRef<'tcx> { | |
cdc7bbd5 | 270 | let (substs, _) = self.create_substs_for_ast_path( |
dc9dc135 XL |
271 | span, |
272 | def_id, | |
dfeec247 | 273 | &[], |
5869c6ff XL |
274 | item_segment, |
275 | item_segment.args(), | |
dc9dc135 XL |
276 | item_segment.infer_args, |
277 | None, | |
278 | ); | |
cdc7bbd5 | 279 | let assoc_bindings = self.create_assoc_bindings_for_generic_args(item_segment.args()); |
1a4d82fc | 280 | |
f9f354fc XL |
281 | if let Some(b) = assoc_bindings.first() { |
282 | Self::prohibit_assoc_ty_binding(self.tcx(), b.span); | |
283 | } | |
1a4d82fc | 284 | |
9e0c209e | 285 | substs |
a7813a04 | 286 | } |
c34b1796 | 287 | |
48663c56 | 288 | /// Given the type/lifetime/const arguments provided to some path (along with |
dc9dc135 | 289 | /// an implicit `Self`, if this is a trait reference), returns the complete |
9e0c209e | 290 | /// set of substitutions. This may involve applying defaulted type parameters. |
5e7ed085 | 291 | /// Constraints on associated types are created from `create_assoc_bindings_for_generic_args`. |
dc9dc135 XL |
292 | /// |
293 | /// Example: | |
294 | /// | |
04454e1e FG |
295 | /// ```ignore (illustrative) |
296 | /// T: std::ops::Index<usize, Output = u32> | |
297 | /// // ^1 ^^^^^^^^^^^^^^2 ^^^^3 ^^^^^^^^^^^4 | |
dc9dc135 XL |
298 | /// ``` |
299 | /// | |
300 | /// 1. The `self_ty` here would refer to the type `T`. | |
301 | /// 2. The path in question is the path to the trait `std::ops::Index`, | |
302 | /// which will have been resolved to a `def_id` | |
303 | /// 3. The `generic_args` contains info on the `<...>` contents. The `usize` type | |
304 | /// parameters are returned in the `SubstsRef`, the associated type bindings like | |
5099ac24 | 305 | /// `Output = u32` are returned from `create_assoc_bindings_for_generic_args`. |
9e0c209e SL |
306 | /// |
307 | /// Note that the type listing given here is *exactly* what the user provided. | |
dfeec247 XL |
308 | /// |
309 | /// For (generic) associated types | |
310 | /// | |
04454e1e | 311 | /// ```ignore (illustrative) |
dfeec247 XL |
312 | /// <Vec<u8> as Iterable<u8>>::Iter::<'a> |
313 | /// ``` | |
314 | /// | |
315 | /// We have the parent substs are the substs for the parent trait: | |
316 | /// `[Vec<u8>, u8]` and `generic_args` are the arguments for the associated | |
317 | /// type itself: `['a]`. The returned `SubstsRef` concatenates these two | |
318 | /// lists: `[Vec<u8>, u8, 'a]`. | |
f2b60f7d | 319 | #[instrument(level = "debug", skip(self, span), ret)] |
dfeec247 XL |
320 | fn create_substs_for_ast_path<'a>( |
321 | &self, | |
a7813a04 | 322 | span: Span, |
9e0c209e | 323 | def_id: DefId, |
dfeec247 | 324 | parent_substs: &[subst::GenericArg<'tcx>], |
5869c6ff | 325 | seg: &hir::PathSegment<'_>, |
dfeec247 | 326 | generic_args: &'a hir::GenericArgs<'_>, |
dc9dc135 | 327 | infer_args: bool, |
dfeec247 | 328 | self_ty: Option<Ty<'tcx>>, |
cdc7bbd5 | 329 | ) -> (SubstsRef<'tcx>, GenericArgCountResult) { |
a7813a04 XL |
330 | // If the type is parameterized by this region, then replace this |
331 | // region with the current anon region binding (in other words, | |
332 | // whatever & would get replaced with). | |
94b46f34 | 333 | |
b7449926 | 334 | let tcx = self.tcx(); |
5869c6ff XL |
335 | let generics = tcx.generics_of(def_id); |
336 | debug!("generics: {:?}", generics); | |
85aaf69f | 337 | |
5869c6ff XL |
338 | if generics.has_self { |
339 | if generics.parent.is_some() { | |
dfeec247 XL |
340 | // The parent is a trait so it should have at least one subst |
341 | // for the `Self` type. | |
342 | assert!(!parent_substs.is_empty()) | |
343 | } else { | |
344 | // This item (presumably a trait) needs a self-type. | |
345 | assert!(self_ty.is_some()); | |
346 | } | |
347 | } else { | |
348 | assert!(self_ty.is_none() && parent_substs.is_empty()); | |
349 | } | |
a7813a04 | 350 | |
f9f354fc | 351 | let arg_count = Self::check_generic_arg_count( |
0731742a | 352 | tcx, |
b7449926 | 353 | span, |
5869c6ff XL |
354 | def_id, |
355 | seg, | |
c295e0f8 XL |
356 | generics, |
357 | generic_args, | |
b7449926 | 358 | GenericArgPosition::Type, |
dfeec247 | 359 | self_ty.is_some(), |
dc9dc135 | 360 | infer_args, |
b7449926 | 361 | ); |
1a4d82fc | 362 | |
fc512014 XL |
363 | // Skip processing if type has no generic parameters. |
364 | // Traits always have `Self` as a generic parameter, which means they will not return early | |
365 | // here and so associated type bindings will be handled regardless of whether there are any | |
366 | // non-`Self` generic parameters. | |
c295e0f8 | 367 | if generics.params.is_empty() { |
cdc7bbd5 | 368 | return (tcx.intern_substs(&[]), arg_count); |
fc512014 XL |
369 | } |
370 | ||
fc512014 XL |
371 | struct SubstsForAstPathCtxt<'a, 'tcx> { |
372 | astconv: &'a (dyn AstConv<'tcx> + 'a), | |
373 | def_id: DefId, | |
374 | generic_args: &'a GenericArgs<'a>, | |
375 | span: Span, | |
fc512014 XL |
376 | inferred_params: Vec<Span>, |
377 | infer_args: bool, | |
fc512014 | 378 | } |
9e0c209e | 379 | |
fc512014 XL |
380 | impl<'a, 'tcx> CreateSubstsForGenericArgsCtxt<'a, 'tcx> for SubstsForAstPathCtxt<'a, 'tcx> { |
381 | fn args_for_def_id(&mut self, did: DefId) -> (Option<&'a GenericArgs<'a>>, bool) { | |
382 | if did == self.def_id { | |
383 | (Some(self.generic_args), self.infer_args) | |
74b04a01 XL |
384 | } else { |
385 | // The last component of this tuple is unimportant. | |
386 | (None, false) | |
387 | } | |
fc512014 XL |
388 | } |
389 | ||
390 | fn provided_kind( | |
391 | &mut self, | |
392 | param: &ty::GenericParamDef, | |
393 | arg: &GenericArg<'_>, | |
394 | ) -> subst::GenericArg<'tcx> { | |
395 | let tcx = self.astconv.tcx(); | |
a2a8927a XL |
396 | |
397 | let mut handle_ty_args = |has_default, ty: &hir::Ty<'_>| { | |
398 | if has_default { | |
399 | tcx.check_optional_stability( | |
400 | param.def_id, | |
f2b60f7d | 401 | Some(arg.hir_id()), |
a2a8927a XL |
402 | arg.span(), |
403 | None, | |
923072b8 | 404 | AllowUnstable::No, |
a2a8927a XL |
405 | |_, _| { |
406 | // Default generic parameters may not be marked | |
407 | // with stability attributes, i.e. when the | |
408 | // default parameter was defined at the same time | |
409 | // as the rest of the type. As such, we ignore missing | |
410 | // stability attributes. | |
411 | }, | |
064997fb | 412 | ); |
a2a8927a XL |
413 | } |
414 | if let (hir::TyKind::Infer, false) = (&ty.kind, self.astconv.allow_ty_infer()) { | |
415 | self.inferred_params.push(ty.span); | |
416 | tcx.ty_error().into() | |
417 | } else { | |
418 | self.astconv.ast_ty_to_ty(ty).into() | |
419 | } | |
420 | }; | |
421 | ||
fc512014 XL |
422 | match (¶m.kind, arg) { |
423 | (GenericParamDefKind::Lifetime, GenericArg::Lifetime(lt)) => { | |
c295e0f8 | 424 | self.astconv.ast_region_to_region(lt, Some(param)).into() |
fc512014 XL |
425 | } |
426 | (&GenericParamDefKind::Type { has_default, .. }, GenericArg::Type(ty)) => { | |
a2a8927a XL |
427 | handle_ty_args(has_default, ty) |
428 | } | |
429 | (&GenericParamDefKind::Type { has_default, .. }, GenericArg::Infer(inf)) => { | |
430 | handle_ty_args(has_default, &inf.to_ty()) | |
fc512014 | 431 | } |
cdc7bbd5 | 432 | (GenericParamDefKind::Const { .. }, GenericArg::Const(ct)) => { |
fc512014 XL |
433 | ty::Const::from_opt_const_arg_anon_const( |
434 | tcx, | |
435 | ty::WithOptConstParam { | |
436 | did: tcx.hir().local_def_id(ct.value.hir_id), | |
437 | const_param_did: Some(param.def_id), | |
1b1a35ee XL |
438 | }, |
439 | ) | |
fc512014 | 440 | .into() |
1b1a35ee | 441 | } |
a2a8927a XL |
442 | (&GenericParamDefKind::Const { .. }, hir::GenericArg::Infer(inf)) => { |
443 | let ty = tcx.at(self.span).type_of(param.def_id); | |
94222f64 | 444 | if self.astconv.allow_ty_infer() { |
a2a8927a | 445 | self.astconv.ct_infer(ty, Some(param), inf.span).into() |
94222f64 XL |
446 | } else { |
447 | self.inferred_params.push(inf.span); | |
a2a8927a | 448 | tcx.const_error(ty).into() |
94222f64 XL |
449 | } |
450 | } | |
fc512014 | 451 | _ => unreachable!(), |
dfeec247 | 452 | } |
fc512014 XL |
453 | } |
454 | ||
455 | fn inferred_kind( | |
456 | &mut self, | |
457 | substs: Option<&[subst::GenericArg<'tcx>]>, | |
458 | param: &ty::GenericParamDef, | |
459 | infer_args: bool, | |
460 | ) -> subst::GenericArg<'tcx> { | |
461 | let tcx = self.astconv.tcx(); | |
b7449926 | 462 | match param.kind { |
5099ac24 FG |
463 | GenericParamDefKind::Lifetime => self |
464 | .astconv | |
465 | .re_infer(Some(param), self.span) | |
466 | .unwrap_or_else(|| { | |
467 | debug!(?param, "unelided lifetime in signature"); | |
468 | ||
469 | // This indicates an illegal lifetime in a non-assoc-trait position | |
470 | tcx.sess.delay_span_bug(self.span, "unelided lifetime in signature"); | |
471 | ||
472 | // Supply some dummy value. We don't have an | |
473 | // `re_error`, annoyingly, so use `'static`. | |
474 | tcx.lifetimes.re_static | |
475 | }) | |
476 | .into(), | |
b7449926 | 477 | GenericParamDefKind::Type { has_default, .. } => { |
dc9dc135 | 478 | if !infer_args && has_default { |
b7449926 | 479 | // No type parameter provided, but a default exists. |
f2b60f7d FG |
480 | let substs = substs.unwrap(); |
481 | if substs.iter().any(|arg| match arg.unpack() { | |
482 | GenericArgKind::Type(ty) => ty.references_error(), | |
483 | _ => false, | |
484 | }) { | |
485 | // Avoid ICE #86756 when type error recovery goes awry. | |
486 | return tcx.ty_error().into(); | |
b7449926 | 487 | } |
f2b60f7d FG |
488 | self.astconv |
489 | .normalize_ty( | |
490 | self.span, | |
491 | EarlyBinder(tcx.at(self.span).type_of(param.def_id)) | |
492 | .subst(tcx, substs), | |
493 | ) | |
494 | .into() | |
dc9dc135 | 495 | } else if infer_args { |
f2b60f7d | 496 | self.astconv.ty_infer(Some(param), self.span).into() |
94b46f34 | 497 | } else { |
b7449926 | 498 | // We've already errored above about the mismatch. |
f035d41b | 499 | tcx.ty_error().into() |
94b46f34 | 500 | } |
94b46f34 | 501 | } |
cdc7bbd5 | 502 | GenericParamDefKind::Const { has_default } => { |
fc512014 | 503 | let ty = tcx.at(self.span).type_of(param.def_id); |
cdc7bbd5 | 504 | if !infer_args && has_default { |
064997fb | 505 | tcx.bound_const_param_default(param.def_id) |
04454e1e | 506 | .subst(tcx, substs.unwrap()) |
cdc7bbd5 | 507 | .into() |
dc9dc135 | 508 | } else { |
cdc7bbd5 XL |
509 | if infer_args { |
510 | self.astconv.ct_infer(ty, Some(param), self.span).into() | |
511 | } else { | |
512 | // We've already errored above about the mismatch. | |
513 | tcx.const_error(ty).into() | |
514 | } | |
dc9dc135 | 515 | } |
532ac7d7 | 516 | } |
a7813a04 | 517 | } |
fc512014 XL |
518 | } |
519 | } | |
520 | ||
521 | let mut substs_ctx = SubstsForAstPathCtxt { | |
522 | astconv: self, | |
523 | def_id, | |
524 | span, | |
525 | generic_args, | |
fc512014 XL |
526 | inferred_params: vec![], |
527 | infer_args, | |
fc512014 XL |
528 | }; |
529 | let substs = Self::create_substs_for_generic_args( | |
530 | tcx, | |
531 | def_id, | |
532 | parent_substs, | |
533 | self_ty.is_some(), | |
534 | self_ty, | |
cdc7bbd5 | 535 | &arg_count, |
fc512014 | 536 | &mut substs_ctx, |
b7449926 | 537 | ); |
1a4d82fc | 538 | |
cdc7bbd5 XL |
539 | (substs, arg_count) |
540 | } | |
541 | ||
542 | fn create_assoc_bindings_for_generic_args<'a>( | |
543 | &self, | |
544 | generic_args: &'a hir::GenericArgs<'_>, | |
545 | ) -> Vec<ConvertedBinding<'a, 'tcx>> { | |
dc9dc135 XL |
546 | // Convert associated-type bindings or constraints into a separate vector. |
547 | // Example: Given this: | |
548 | // | |
549 | // T: Iterator<Item = u32> | |
550 | // | |
551 | // The `T` is passed in as a self-type; the `Item = u32` is | |
552 | // not a "type parameter" of the `Iterator` trait, but rather | |
553 | // a restriction on `<T as Iterator>::Item`, so it is passed | |
554 | // back separately. | |
dfeec247 XL |
555 | let assoc_bindings = generic_args |
556 | .bindings | |
557 | .iter() | |
dc9dc135 XL |
558 | .map(|binding| { |
559 | let kind = match binding.kind { | |
5099ac24 FG |
560 | hir::TypeBindingKind::Equality { ref term } => match term { |
561 | hir::Term::Ty(ref ty) => { | |
562 | ConvertedBindingKind::Equality(self.ast_ty_to_ty(ty).into()) | |
563 | } | |
564 | hir::Term::Const(ref c) => { | |
565 | let local_did = self.tcx().hir().local_def_id(c.hir_id); | |
566 | let c = Const::from_anon_const(self.tcx(), local_did); | |
567 | ConvertedBindingKind::Equality(c.into()) | |
568 | } | |
569 | }, | |
570 | hir::TypeBindingKind::Constraint { ref bounds } => { | |
dfeec247 XL |
571 | ConvertedBindingKind::Constraint(bounds) |
572 | } | |
dc9dc135 | 573 | }; |
5869c6ff | 574 | ConvertedBinding { |
17df50a5 | 575 | hir_id: binding.hir_id, |
5869c6ff XL |
576 | item_name: binding.ident, |
577 | kind, | |
578 | gen_args: binding.gen_args, | |
579 | span: binding.span, | |
580 | } | |
dc9dc135 XL |
581 | }) |
582 | .collect(); | |
a7813a04 | 583 | |
cdc7bbd5 | 584 | assoc_bindings |
e9174d1e | 585 | } |
e9174d1e | 586 | |
923072b8 | 587 | pub(crate) fn create_substs_for_associated_item( |
dfeec247 XL |
588 | &self, |
589 | tcx: TyCtxt<'tcx>, | |
590 | span: Span, | |
591 | item_def_id: DefId, | |
592 | item_segment: &hir::PathSegment<'_>, | |
593 | parent_substs: SubstsRef<'tcx>, | |
594 | ) -> SubstsRef<'tcx> { | |
17df50a5 XL |
595 | debug!( |
596 | "create_substs_for_associated_item(span: {:?}, item_def_id: {:?}, item_segment: {:?}", | |
597 | span, item_def_id, item_segment | |
598 | ); | |
dfeec247 | 599 | if tcx.generics_of(item_def_id).params.is_empty() { |
923072b8 | 600 | self.prohibit_generics(slice::from_ref(item_segment).iter(), |_| {}); |
dfeec247 XL |
601 | |
602 | parent_substs | |
603 | } else { | |
f2b60f7d | 604 | let (args, _) = self.create_substs_for_ast_path( |
dfeec247 XL |
605 | span, |
606 | item_def_id, | |
607 | parent_substs, | |
5869c6ff XL |
608 | item_segment, |
609 | item_segment.args(), | |
dfeec247 XL |
610 | item_segment.infer_args, |
611 | None, | |
f2b60f7d FG |
612 | ); |
613 | ||
614 | let assoc_bindings = self.create_assoc_bindings_for_generic_args(item_segment.args()); | |
615 | if let Some(b) = assoc_bindings.first() { | |
616 | Self::prohibit_assoc_ty_binding(self.tcx(), b.span); | |
617 | } | |
618 | ||
619 | args | |
dfeec247 XL |
620 | } |
621 | } | |
622 | ||
a7813a04 | 623 | /// Instantiates the path for the given trait reference, assuming that it's |
dc9dc135 | 624 | /// bound to a valid trait type. Returns the `DefId` of the defining trait. |
0531ce1d | 625 | /// The type _cannot_ be a type other than a trait type. |
a7813a04 | 626 | /// |
9fa01778 | 627 | /// If the `projections` argument is `None`, then assoc type bindings like `Foo<T = X>` |
a7813a04 | 628 | /// are disallowed. Otherwise, they are pushed onto the vector given. |
dfeec247 XL |
629 | pub fn instantiate_mono_trait_ref( |
630 | &self, | |
631 | trait_ref: &hir::TraitRef<'_>, | |
632 | self_ty: Ty<'tcx>, | |
633 | ) -> ty::TraitRef<'tcx> { | |
923072b8 | 634 | self.prohibit_generics(trait_ref.path.segments.split_last().unwrap().1.iter(), |_| {}); |
7cac9316 | 635 | |
dfeec247 XL |
636 | self.ast_path_to_mono_trait_ref( |
637 | trait_ref.path.span, | |
ba9703b0 | 638 | trait_ref.trait_def_id().unwrap_or_else(|| FatalError.raise()), |
dfeec247 XL |
639 | self_ty, |
640 | trait_ref.path.segments.last().unwrap(), | |
5099ac24 | 641 | true, |
dfeec247 | 642 | ) |
1a4d82fc | 643 | } |
c34b1796 | 644 | |
c295e0f8 XL |
645 | fn instantiate_poly_trait_ref_inner( |
646 | &self, | |
647 | hir_id: hir::HirId, | |
648 | span: Span, | |
649 | binding_span: Option<Span>, | |
650 | constness: ty::BoundConstness, | |
651 | bounds: &mut Bounds<'tcx>, | |
652 | speculative: bool, | |
653 | trait_ref_span: Span, | |
654 | trait_def_id: DefId, | |
655 | trait_segment: &hir::PathSegment<'_>, | |
656 | args: &GenericArgs<'_>, | |
657 | infer_args: bool, | |
658 | self_ty: Ty<'tcx>, | |
659 | ) -> GenericArgCountResult { | |
660 | let (substs, arg_count) = self.create_substs_for_ast_path( | |
661 | trait_ref_span, | |
662 | trait_def_id, | |
663 | &[], | |
664 | trait_segment, | |
665 | args, | |
666 | infer_args, | |
667 | Some(self_ty), | |
668 | ); | |
669 | ||
670 | let tcx = self.tcx(); | |
671 | let bound_vars = tcx.late_bound_vars(hir_id); | |
672 | debug!(?bound_vars); | |
673 | ||
674 | let assoc_bindings = self.create_assoc_bindings_for_generic_args(args); | |
675 | ||
676 | let poly_trait_ref = | |
677 | ty::Binder::bind_with_vars(ty::TraitRef::new(trait_def_id, substs), bound_vars); | |
678 | ||
679 | debug!(?poly_trait_ref, ?assoc_bindings); | |
680 | bounds.trait_bounds.push((poly_trait_ref, span, constness)); | |
681 | ||
682 | let mut dup_bindings = FxHashMap::default(); | |
683 | for binding in &assoc_bindings { | |
684 | // Specify type to assert that error was already reported in `Err` case. | |
5e7ed085 | 685 | let _: Result<_, ErrorGuaranteed> = self.add_predicates_for_ast_type_binding( |
c295e0f8 XL |
686 | hir_id, |
687 | poly_trait_ref, | |
688 | binding, | |
689 | bounds, | |
690 | speculative, | |
691 | &mut dup_bindings, | |
692 | binding_span.unwrap_or(binding.span), | |
693 | ); | |
5e7ed085 | 694 | // Okay to ignore `Err` because of `ErrorGuaranteed` (see above). |
c295e0f8 XL |
695 | } |
696 | ||
697 | arg_count | |
698 | } | |
699 | ||
cdc7bbd5 XL |
700 | /// Given a trait bound like `Debug`, applies that trait bound the given self-type to construct |
701 | /// a full trait reference. The resulting trait reference is returned. This may also generate | |
702 | /// auxiliary bounds, which are added to `bounds`. | |
703 | /// | |
704 | /// Example: | |
705 | /// | |
04454e1e | 706 | /// ```ignore (illustrative) |
cdc7bbd5 XL |
707 | /// poly_trait_ref = Iterator<Item = u32> |
708 | /// self_ty = Foo | |
709 | /// ``` | |
710 | /// | |
711 | /// this would return `Foo: Iterator` and add `<Foo as Iterator>::Item = u32` into `bounds`. | |
712 | /// | |
713 | /// **A note on binders:** against our usual convention, there is an implied bounder around | |
714 | /// the `self_ty` and `poly_trait_ref` parameters here. So they may reference bound regions. | |
715 | /// If for example you had `for<'a> Foo<'a>: Bar<'a>`, then the `self_ty` would be `Foo<'a>` | |
716 | /// where `'a` is a bound region at depth 0. Similarly, the `poly_trait_ref` would be | |
717 | /// `Bar<'a>`. The returned poly-trait-ref will have this binder instantiated explicitly, | |
718 | /// however. | |
f2b60f7d | 719 | #[instrument(level = "debug", skip(self, span, constness, bounds, speculative))] |
c295e0f8 | 720 | pub(crate) fn instantiate_poly_trait_ref( |
dfeec247 XL |
721 | &self, |
722 | trait_ref: &hir::TraitRef<'_>, | |
416331ca | 723 | span: Span, |
94222f64 | 724 | constness: ty::BoundConstness, |
9e0c209e | 725 | self_ty: Ty<'tcx>, |
dc9dc135 XL |
726 | bounds: &mut Bounds<'tcx>, |
727 | speculative: bool, | |
f9f354fc | 728 | ) -> GenericArgCountResult { |
c295e0f8 XL |
729 | let hir_id = trait_ref.hir_ref_id; |
730 | let binding_span = None; | |
731 | let trait_ref_span = trait_ref.path.span; | |
ba9703b0 | 732 | let trait_def_id = trait_ref.trait_def_id().unwrap_or_else(|| FatalError.raise()); |
c295e0f8 XL |
733 | let trait_segment = trait_ref.path.segments.last().unwrap(); |
734 | let args = trait_segment.args(); | |
735 | let infer_args = trait_segment.infer_args; | |
32a655c1 | 736 | |
923072b8 | 737 | self.prohibit_generics(trait_ref.path.segments.split_last().unwrap().1.iter(), |_| {}); |
5099ac24 | 738 | self.complain_about_internal_fn_trait(span, trait_def_id, trait_segment, false); |
7cac9316 | 739 | |
c295e0f8 XL |
740 | self.instantiate_poly_trait_ref_inner( |
741 | hir_id, | |
742 | span, | |
743 | binding_span, | |
744 | constness, | |
745 | bounds, | |
746 | speculative, | |
747 | trait_ref_span, | |
a1dfa0c6 | 748 | trait_def_id, |
c295e0f8 XL |
749 | trait_segment, |
750 | args, | |
751 | infer_args, | |
a1dfa0c6 | 752 | self_ty, |
c295e0f8 | 753 | ) |
c34b1796 AL |
754 | } |
755 | ||
c295e0f8 | 756 | pub(crate) fn instantiate_lang_item_trait_ref( |
3dfed10e XL |
757 | &self, |
758 | lang_item: hir::LangItem, | |
759 | span: Span, | |
760 | hir_id: hir::HirId, | |
761 | args: &GenericArgs<'_>, | |
762 | self_ty: Ty<'tcx>, | |
763 | bounds: &mut Bounds<'tcx>, | |
764 | ) { | |
c295e0f8 XL |
765 | let binding_span = Some(span); |
766 | let constness = ty::BoundConstness::NotConst; | |
767 | let speculative = false; | |
768 | let trait_ref_span = span; | |
3dfed10e | 769 | let trait_def_id = self.tcx().require_lang_item(lang_item, Some(span)); |
c295e0f8 XL |
770 | let trait_segment = &hir::PathSegment::invalid(); |
771 | let infer_args = false; | |
3dfed10e | 772 | |
c295e0f8 XL |
773 | self.instantiate_poly_trait_ref_inner( |
774 | hir_id, | |
5869c6ff | 775 | span, |
c295e0f8 XL |
776 | binding_span, |
777 | constness, | |
778 | bounds, | |
779 | speculative, | |
780 | trait_ref_span, | |
5869c6ff | 781 | trait_def_id, |
c295e0f8 | 782 | trait_segment, |
5869c6ff | 783 | args, |
c295e0f8 XL |
784 | infer_args, |
785 | self_ty, | |
5869c6ff | 786 | ); |
3dfed10e XL |
787 | } |
788 | ||
dfeec247 XL |
789 | fn ast_path_to_mono_trait_ref( |
790 | &self, | |
dc9dc135 XL |
791 | span: Span, |
792 | trait_def_id: DefId, | |
793 | self_ty: Ty<'tcx>, | |
dfeec247 | 794 | trait_segment: &hir::PathSegment<'_>, |
5099ac24 | 795 | is_impl: bool, |
dfeec247 | 796 | ) -> ty::TraitRef<'tcx> { |
5099ac24 FG |
797 | let (substs, _) = self.create_substs_for_ast_trait_ref( |
798 | span, | |
799 | trait_def_id, | |
800 | self_ty, | |
801 | trait_segment, | |
802 | is_impl, | |
803 | ); | |
cdc7bbd5 | 804 | let assoc_bindings = self.create_assoc_bindings_for_generic_args(trait_segment.args()); |
f9f354fc | 805 | if let Some(b) = assoc_bindings.first() { |
3dfed10e | 806 | Self::prohibit_assoc_ty_binding(self.tcx(), b.span); |
f9f354fc | 807 | } |
a7813a04 XL |
808 | ty::TraitRef::new(trait_def_id, substs) |
809 | } | |
c34b1796 | 810 | |
f2b60f7d | 811 | #[instrument(level = "debug", skip(self, span))] |
dfeec247 XL |
812 | fn create_substs_for_ast_trait_ref<'a>( |
813 | &self, | |
814 | span: Span, | |
815 | trait_def_id: DefId, | |
816 | self_ty: Ty<'tcx>, | |
817 | trait_segment: &'a hir::PathSegment<'a>, | |
5099ac24 | 818 | is_impl: bool, |
cdc7bbd5 | 819 | ) -> (SubstsRef<'tcx>, GenericArgCountResult) { |
5099ac24 | 820 | self.complain_about_internal_fn_trait(span, trait_def_id, trait_segment, is_impl); |
dfeec247 XL |
821 | |
822 | self.create_substs_for_ast_path( | |
823 | span, | |
824 | trait_def_id, | |
825 | &[], | |
5869c6ff XL |
826 | trait_segment, |
827 | trait_segment.args(), | |
dfeec247 XL |
828 | trait_segment.infer_args, |
829 | Some(self_ty), | |
830 | ) | |
a7813a04 | 831 | } |
1a4d82fc | 832 | |
f9f354fc | 833 | fn trait_defines_associated_type_named(&self, trait_def_id: DefId, assoc_name: Ident) -> bool { |
74b04a01 XL |
834 | self.tcx() |
835 | .associated_items(trait_def_id) | |
836 | .find_by_name_and_kind(self.tcx(), assoc_name, ty::AssocKind::Type, trait_def_id) | |
837 | .is_some() | |
476ff2be | 838 | } |
5099ac24 FG |
839 | fn trait_defines_associated_const_named(&self, trait_def_id: DefId, assoc_name: Ident) -> bool { |
840 | self.tcx() | |
841 | .associated_items(trait_def_id) | |
842 | .find_by_name_and_kind(self.tcx(), assoc_name, ty::AssocKind::Const, trait_def_id) | |
843 | .is_some() | |
844 | } | |
476ff2be | 845 | |
c295e0f8 XL |
846 | // Sets `implicitly_sized` to true on `Bounds` if necessary |
847 | pub(crate) fn add_implicitly_sized<'hir>( | |
848 | &self, | |
849 | bounds: &mut Bounds<'hir>, | |
850 | ast_bounds: &'hir [hir::GenericBound<'hir>], | |
851 | self_ty_where_predicates: Option<(hir::HirId, &'hir [hir::WherePredicate<'hir>])>, | |
852 | span: Span, | |
853 | ) { | |
dc9dc135 XL |
854 | let tcx = self.tcx(); |
855 | ||
856 | // Try to find an unbound in bounds. | |
857 | let mut unbound = None; | |
c295e0f8 XL |
858 | let mut search_bounds = |ast_bounds: &'hir [hir::GenericBound<'hir>]| { |
859 | for ab in ast_bounds { | |
860 | if let hir::GenericBound::Trait(ptr, hir::TraitBoundModifier::Maybe) = ab { | |
861 | if unbound.is_none() { | |
862 | unbound = Some(&ptr.trait_ref); | |
863 | } else { | |
864 | tcx.sess.emit_err(MultipleRelaxedDefaultBounds { span }); | |
865 | } | |
dc9dc135 XL |
866 | } |
867 | } | |
c295e0f8 XL |
868 | }; |
869 | search_bounds(ast_bounds); | |
870 | if let Some((self_ty, where_clause)) = self_ty_where_predicates { | |
871 | let self_ty_def_id = tcx.hir().local_def_id(self_ty).to_def_id(); | |
872 | for clause in where_clause { | |
873 | if let hir::WherePredicate::BoundPredicate(pred) = clause { | |
04454e1e FG |
874 | if pred.is_param_bound(self_ty_def_id) { |
875 | search_bounds(pred.bounds); | |
dc9dc135 XL |
876 | } |
877 | } | |
878 | } | |
c295e0f8 XL |
879 | } |
880 | ||
881 | let sized_def_id = tcx.lang_items().require(LangItem::Sized); | |
882 | match (&sized_def_id, unbound) { | |
883 | (Ok(sized_def_id), Some(tpb)) | |
884 | if tpb.path.res == Res::Def(DefKind::Trait, *sized_def_id) => | |
885 | { | |
886 | // There was in fact a `?Sized` bound, return without doing anything | |
887 | return; | |
dc9dc135 | 888 | } |
c295e0f8 XL |
889 | (_, Some(_)) => { |
890 | // There was a `?Trait` bound, but it was not `?Sized`; warn. | |
891 | tcx.sess.span_warn( | |
892 | span, | |
893 | "default bound relaxed for a type parameter, but \ | |
894 | this does nothing because the given bound is not \ | |
895 | a default; only `?Sized` is supported", | |
896 | ); | |
897 | // Otherwise, add implicitly sized if `Sized` is available. | |
898 | } | |
899 | _ => { | |
900 | // There was no `?Sized` bound; add implicitly sized if `Sized` is available. | |
901 | } | |
902 | } | |
903 | if sized_def_id.is_err() { | |
dc9dc135 | 904 | // No lang item for `Sized`, so we can't add it as a bound. |
c295e0f8 | 905 | return; |
dc9dc135 | 906 | } |
c295e0f8 | 907 | bounds.implicitly_sized = Some(span); |
dc9dc135 XL |
908 | } |
909 | ||
910 | /// This helper takes a *converted* parameter type (`param_ty`) | |
911 | /// and an *unconverted* list of bounds: | |
912 | /// | |
ba9703b0 | 913 | /// ```text |
dc9dc135 XL |
914 | /// fn foo<T: Debug> |
915 | /// ^ ^^^^^ `ast_bounds` parameter, in HIR form | |
916 | /// | | |
917 | /// `param_ty`, in ty form | |
918 | /// ``` | |
919 | /// | |
920 | /// It adds these `ast_bounds` into the `bounds` structure. | |
921 | /// | |
922 | /// **A note on binders:** there is an implied binder around | |
923 | /// `param_ty` and `ast_bounds`. See `instantiate_poly_trait_ref` | |
924 | /// for more details. | |
f2b60f7d | 925 | #[instrument(level = "debug", skip(self, ast_bounds, bounds))] |
c295e0f8 | 926 | pub(crate) fn add_bounds<'hir, I: Iterator<Item = &'hir hir::GenericBound<'hir>>>( |
dfeec247 | 927 | &self, |
dc9dc135 | 928 | param_ty: Ty<'tcx>, |
c295e0f8 | 929 | ast_bounds: I, |
dc9dc135 | 930 | bounds: &mut Bounds<'tcx>, |
cdc7bbd5 | 931 | bound_vars: &'tcx ty::List<ty::BoundVariableKind>, |
dc9dc135 | 932 | ) { |
dc9dc135 | 933 | for ast_bound in ast_bounds { |
c295e0f8 XL |
934 | match ast_bound { |
935 | hir::GenericBound::Trait(poly_trait_ref, modifier) => { | |
936 | let constness = match modifier { | |
937 | hir::TraitBoundModifier::MaybeConst => ty::BoundConstness::ConstIfConst, | |
938 | hir::TraitBoundModifier::None => ty::BoundConstness::NotConst, | |
939 | hir::TraitBoundModifier::Maybe => continue, | |
940 | }; | |
941 | ||
942 | let _ = self.instantiate_poly_trait_ref( | |
943 | &poly_trait_ref.trait_ref, | |
944 | poly_trait_ref.span, | |
945 | constness, | |
cdc7bbd5 XL |
946 | param_ty, |
947 | bounds, | |
948 | false, | |
949 | ); | |
dfeec247 | 950 | } |
c295e0f8 XL |
951 | &hir::GenericBound::LangItemTrait(lang_item, span, hir_id, args) => { |
952 | self.instantiate_lang_item_trait_ref( | |
953 | lang_item, span, hir_id, args, param_ty, bounds, | |
cdc7bbd5 | 954 | ); |
dfeec247 | 955 | } |
c295e0f8 XL |
956 | hir::GenericBound::Outlives(lifetime) => { |
957 | let region = self.ast_region_to_region(lifetime, None); | |
958 | bounds | |
959 | .region_bounds | |
960 | .push((ty::Binder::bind_with_vars(region, bound_vars), lifetime.span)); | |
961 | } | |
dc9dc135 XL |
962 | } |
963 | } | |
dc9dc135 XL |
964 | } |
965 | ||
966 | /// Translates a list of bounds from the HIR into the `Bounds` data structure. | |
967 | /// The self-type for the bounds is given by `param_ty`. | |
968 | /// | |
969 | /// Example: | |
970 | /// | |
04454e1e | 971 | /// ```ignore (illustrative) |
dc9dc135 | 972 | /// fn foo<T: Bar + Baz>() { } |
04454e1e FG |
973 | /// // ^ ^^^^^^^^^ ast_bounds |
974 | /// // param_ty | |
dc9dc135 XL |
975 | /// ``` |
976 | /// | |
977 | /// The `sized_by_default` parameter indicates if, in this context, the `param_ty` should be | |
978 | /// considered `Sized` unless there is an explicit `?Sized` bound. This would be true in the | |
979 | /// example above, but is not true in supertrait listings like `trait Foo: Bar + Baz`. | |
980 | /// | |
981 | /// `span` should be the declaration size of the parameter. | |
c295e0f8 | 982 | pub(crate) fn compute_bounds( |
dfeec247 | 983 | &self, |
dc9dc135 | 984 | param_ty: Ty<'tcx>, |
dfeec247 | 985 | ast_bounds: &[hir::GenericBound<'_>], |
6a06907d | 986 | ) -> Bounds<'tcx> { |
c295e0f8 | 987 | self.compute_bounds_inner(param_ty, ast_bounds) |
6a06907d XL |
988 | } |
989 | ||
990 | /// Convert the bounds in `ast_bounds` that refer to traits which define an associated type | |
991 | /// named `assoc_name` into ty::Bounds. Ignore the rest. | |
c295e0f8 | 992 | pub(crate) fn compute_bounds_that_match_assoc_type( |
6a06907d XL |
993 | &self, |
994 | param_ty: Ty<'tcx>, | |
995 | ast_bounds: &[hir::GenericBound<'_>], | |
6a06907d XL |
996 | assoc_name: Ident, |
997 | ) -> Bounds<'tcx> { | |
998 | let mut result = Vec::new(); | |
999 | ||
1000 | for ast_bound in ast_bounds { | |
5e7ed085 FG |
1001 | if let Some(trait_ref) = ast_bound.trait_ref() |
1002 | && let Some(trait_did) = trait_ref.trait_def_id() | |
1003 | && self.tcx().trait_may_define_assoc_type(trait_did, assoc_name) | |
1004 | { | |
1005 | result.push(ast_bound.clone()); | |
6a06907d XL |
1006 | } |
1007 | } | |
1008 | ||
c295e0f8 | 1009 | self.compute_bounds_inner(param_ty, &result) |
6a06907d XL |
1010 | } |
1011 | ||
1012 | fn compute_bounds_inner( | |
1013 | &self, | |
1014 | param_ty: Ty<'tcx>, | |
cdc7bbd5 | 1015 | ast_bounds: &[hir::GenericBound<'_>], |
dc9dc135 XL |
1016 | ) -> Bounds<'tcx> { |
1017 | let mut bounds = Bounds::default(); | |
1018 | ||
c295e0f8 | 1019 | self.add_bounds(param_ty, ast_bounds.iter(), &mut bounds, ty::List::empty()); |
04454e1e | 1020 | debug!(?bounds); |
dc9dc135 XL |
1021 | |
1022 | bounds | |
1023 | } | |
1024 | ||
1025 | /// Given an HIR binding like `Item = Foo` or `Item: Foo`, pushes the corresponding predicates | |
1026 | /// onto `bounds`. | |
1027 | /// | |
1028 | /// **A note on binders:** given something like `T: for<'a> Iterator<Item = &'a u32>`, the | |
1029 | /// `trait_ref` here will be `for<'a> T: Iterator`. The `binding` data however is from *inside* | |
1030 | /// the binder (e.g., `&'a u32`) and hence may reference bound regions. | |
f2b60f7d | 1031 | #[instrument(level = "debug", skip(self, bounds, speculative, dup_bindings, path_span))] |
dc9dc135 | 1032 | fn add_predicates_for_ast_type_binding( |
a7813a04 | 1033 | &self, |
532ac7d7 | 1034 | hir_ref_id: hir::HirId, |
9e0c209e | 1035 | trait_ref: ty::PolyTraitRef<'tcx>, |
dc9dc135 XL |
1036 | binding: &ConvertedBinding<'_, 'tcx>, |
1037 | bounds: &mut Bounds<'tcx>, | |
94b46f34 | 1038 | speculative: bool, |
dc9dc135 | 1039 | dup_bindings: &mut FxHashMap<DefId, Span>, |
dfeec247 | 1040 | path_span: Span, |
5e7ed085 | 1041 | ) -> Result<(), ErrorGuaranteed> { |
5869c6ff XL |
1042 | // Given something like `U: SomeTrait<T = X>`, we want to produce a |
1043 | // predicate like `<U as SomeTrait>::T = X`. This is somewhat | |
1044 | // subtle in the event that `T` is defined in a supertrait of | |
1045 | // `SomeTrait`, because in that case we need to upcast. | |
1046 | // | |
1047 | // That is, consider this case: | |
1048 | // | |
1049 | // ``` | |
1050 | // trait SubTrait: SuperTrait<i32> { } | |
1051 | // trait SuperTrait<A> { type T; } | |
1052 | // | |
1053 | // ... B: SubTrait<T = foo> ... | |
1054 | // ``` | |
1055 | // | |
1056 | // We want to produce `<B as SuperTrait<i32>>::T == foo`. | |
3dfed10e | 1057 | |
5869c6ff | 1058 | let tcx = self.tcx(); |
a7813a04 | 1059 | |
dfeec247 XL |
1060 | let candidate = |
1061 | if self.trait_defines_associated_type_named(trait_ref.def_id(), binding.item_name) { | |
1062 | // Simple case: X is defined in the current trait. | |
1063 | trait_ref | |
1064 | } else { | |
1065 | // Otherwise, we have to walk through the supertraits to find | |
1066 | // those that do. | |
1067 | self.one_bound_for_assoc_type( | |
1068 | || traits::supertraits(tcx, trait_ref), | |
1069 | || trait_ref.print_only_trait_path().to_string(), | |
1070 | binding.item_name, | |
1071 | path_span, | |
1072 | || match binding.kind { | |
1073 | ConvertedBindingKind::Equality(ty) => Some(ty.to_string()), | |
1074 | _ => None, | |
1075 | }, | |
1076 | )? | |
1077 | }; | |
ff7c6d11 | 1078 | |
94b46f34 | 1079 | let (assoc_ident, def_scope) = |
dc9dc135 | 1080 | tcx.adjust_ident_and_get_scope(binding.item_name, candidate.def_id(), hir_ref_id); |
74b04a01 | 1081 | |
ba9703b0 | 1082 | // We have already adjusted the item name above, so compare with `ident.normalize_to_macros_2_0()` instead |
74b04a01 | 1083 | // of calling `filter_by_name_and_kind`. |
5099ac24 FG |
1084 | let find_item_of_kind = |kind| { |
1085 | tcx.associated_items(candidate.def_id()) | |
1086 | .filter_by_name_unhygienic(assoc_ident.name) | |
1087 | .find(|i| i.kind == kind && i.ident(tcx).normalize_to_macros_2_0() == assoc_ident) | |
1088 | }; | |
1089 | let assoc_item = find_item_of_kind(ty::AssocKind::Type) | |
1090 | .or_else(|| find_item_of_kind(ty::AssocKind::Const)) | |
dfeec247 | 1091 | .expect("missing associated type"); |
ff7c6d11 | 1092 | |
064997fb | 1093 | if !assoc_item.visibility(tcx).is_accessible_from(def_scope, tcx) { |
ba9703b0 XL |
1094 | tcx.sess |
1095 | .struct_span_err( | |
1096 | binding.span, | |
064997fb | 1097 | &format!("{} `{}` is private", assoc_item.kind, binding.item_name), |
ba9703b0 | 1098 | ) |
064997fb | 1099 | .span_label(binding.span, &format!("private {}", assoc_item.kind)) |
ba9703b0 | 1100 | .emit(); |
a7813a04 | 1101 | } |
5099ac24 | 1102 | tcx.check_stability(assoc_item.def_id, Some(hir_ref_id), binding.span, None); |
a7813a04 | 1103 | |
94b46f34 | 1104 | if !speculative { |
dfeec247 | 1105 | dup_bindings |
5099ac24 | 1106 | .entry(assoc_item.def_id) |
94b46f34 | 1107 | .and_modify(|prev_span| { |
1b1a35ee XL |
1108 | self.tcx().sess.emit_err(ValueOfAssociatedStructAlreadySpecified { |
1109 | span: binding.span, | |
1110 | prev_span: *prev_span, | |
1111 | item_name: binding.item_name, | |
064997fb | 1112 | def_path: tcx.def_path_str(assoc_item.container_id(tcx)), |
1b1a35ee | 1113 | }); |
94b46f34 XL |
1114 | }) |
1115 | .or_insert(binding.span); | |
1116 | } | |
1117 | ||
5869c6ff XL |
1118 | // Include substitutions for generic parameters of associated types |
1119 | let projection_ty = candidate.map_bound(|trait_ref| { | |
5099ac24 | 1120 | let ident = Ident::new(assoc_item.name, binding.item_name.span); |
5869c6ff | 1121 | let item_segment = hir::PathSegment { |
17df50a5 | 1122 | ident, |
f2b60f7d FG |
1123 | hir_id: binding.hir_id, |
1124 | res: Res::Err, | |
5869c6ff XL |
1125 | args: Some(binding.gen_args), |
1126 | infer_args: false, | |
1127 | }; | |
1128 | ||
1129 | let substs_trait_ref_and_assoc_item = self.create_substs_for_associated_item( | |
1130 | tcx, | |
1131 | path_span, | |
5099ac24 | 1132 | assoc_item.def_id, |
5869c6ff XL |
1133 | &item_segment, |
1134 | trait_ref.substs, | |
1135 | ); | |
1136 | ||
1137 | debug!( | |
1138 | "add_predicates_for_ast_type_binding: substs for trait-ref and assoc_item: {:?}", | |
1139 | substs_trait_ref_and_assoc_item | |
1140 | ); | |
1141 | ||
1142 | ty::ProjectionTy { | |
5099ac24 | 1143 | item_def_id: assoc_item.def_id, |
5869c6ff XL |
1144 | substs: substs_trait_ref_and_assoc_item, |
1145 | } | |
1146 | }); | |
1147 | ||
1148 | if !speculative { | |
1149 | // Find any late-bound regions declared in `ty` that are not | |
5099ac24 | 1150 | // declared in the trait-ref or assoc_item. These are not well-formed. |
5869c6ff XL |
1151 | // |
1152 | // Example: | |
1153 | // | |
1154 | // for<'a> <T as Iterator>::Item = &'a str // <-- 'a is bad | |
1155 | // for<'a> <T as FnMut<(&'a u32,)>>::Output = &'a str // <-- 'a is ok | |
1156 | if let ConvertedBindingKind::Equality(ty) = binding.kind { | |
1157 | let late_bound_in_trait_ref = | |
1158 | tcx.collect_constrained_late_bound_regions(&projection_ty); | |
1159 | let late_bound_in_ty = | |
cdc7bbd5 | 1160 | tcx.collect_referenced_late_bound_regions(&trait_ref.rebind(ty)); |
5869c6ff XL |
1161 | debug!("late_bound_in_trait_ref = {:?}", late_bound_in_trait_ref); |
1162 | debug!("late_bound_in_ty = {:?}", late_bound_in_ty); | |
1163 | ||
1164 | // FIXME: point at the type params that don't have appropriate lifetimes: | |
1165 | // struct S1<F: for<'a> Fn(&i32, &i32) -> &'a i32>(F); | |
1166 | // ---- ---- ^^^^^^^ | |
1167 | self.validate_late_bound_regions( | |
1168 | late_bound_in_trait_ref, | |
1169 | late_bound_in_ty, | |
1170 | |br_name| { | |
1171 | struct_span_err!( | |
1172 | tcx.sess, | |
1173 | binding.span, | |
1174 | E0582, | |
1175 | "binding for associated type `{}` references {}, \ | |
1176 | which does not appear in the trait input types", | |
1177 | binding.item_name, | |
1178 | br_name | |
1179 | ) | |
1180 | }, | |
1181 | ); | |
1182 | } | |
1183 | } | |
1184 | ||
dc9dc135 | 1185 | match binding.kind { |
064997fb | 1186 | ConvertedBindingKind::Equality(mut term) => { |
dc9dc135 XL |
1187 | // "Desugar" a constraint like `T: Iterator<Item = u32>` this to |
1188 | // the "projection predicate" for: | |
1189 | // | |
1190 | // `<T as Iterator>::Item = u32` | |
5099ac24 FG |
1191 | let assoc_item_def_id = projection_ty.skip_binder().item_def_id; |
1192 | let def_kind = tcx.def_kind(assoc_item_def_id); | |
f2b60f7d FG |
1193 | match (def_kind, term.unpack()) { |
1194 | (hir::def::DefKind::AssocTy, ty::TermKind::Ty(_)) | |
1195 | | (hir::def::DefKind::AssocConst, ty::TermKind::Const(_)) => (), | |
5099ac24 | 1196 | (_, _) => { |
f2b60f7d | 1197 | let got = if let Some(_) = term.ty() { "type" } else { "constant" }; |
5099ac24 FG |
1198 | let expected = def_kind.descr(assoc_item_def_id); |
1199 | tcx.sess | |
1200 | .struct_span_err( | |
1201 | binding.span, | |
064997fb | 1202 | &format!("expected {expected} bound, found {got}"), |
5099ac24 FG |
1203 | ) |
1204 | .span_note( | |
1205 | tcx.def_span(assoc_item_def_id), | |
064997fb | 1206 | &format!("{expected} defined here"), |
5099ac24 FG |
1207 | ) |
1208 | .emit(); | |
064997fb FG |
1209 | term = match def_kind { |
1210 | hir::def::DefKind::AssocTy => tcx.ty_error().into(), | |
1211 | hir::def::DefKind::AssocConst => tcx | |
1212 | .const_error( | |
1213 | tcx.bound_type_of(assoc_item_def_id) | |
1214 | .subst(tcx, projection_ty.skip_binder().substs), | |
1215 | ) | |
1216 | .into(), | |
1217 | _ => unreachable!(), | |
1218 | }; | |
5099ac24 FG |
1219 | } |
1220 | } | |
dfeec247 | 1221 | bounds.projection_bounds.push(( |
5099ac24 FG |
1222 | projection_ty.map_bound(|projection_ty| ty::ProjectionPredicate { |
1223 | projection_ty, | |
1224 | term: term, | |
dfeec247 XL |
1225 | }), |
1226 | binding.span, | |
1227 | )); | |
9e0c209e | 1228 | } |
dc9dc135 XL |
1229 | ConvertedBindingKind::Constraint(ast_bounds) => { |
1230 | // "Desugar" a constraint like `T: Iterator<Item: Debug>` to | |
1231 | // | |
1232 | // `<T as Iterator>::Item: Debug` | |
1233 | // | |
1234 | // Calling `skip_binder` is okay, because `add_bounds` expects the `param_ty` | |
1235 | // parameter to have a skipped binder. | |
cdc7bbd5 | 1236 | let param_ty = tcx.mk_ty(ty::Projection(projection_ty.skip_binder())); |
c295e0f8 | 1237 | self.add_bounds(param_ty, ast_bounds.iter(), bounds, candidate.bound_vars()); |
dc9dc135 XL |
1238 | } |
1239 | } | |
1240 | Ok(()) | |
1a4d82fc JJ |
1241 | } |
1242 | ||
dfeec247 XL |
1243 | fn ast_path_to_ty( |
1244 | &self, | |
a7813a04 | 1245 | span: Span, |
a7813a04 | 1246 | did: DefId, |
dfeec247 XL |
1247 | item_segment: &hir::PathSegment<'_>, |
1248 | ) -> Ty<'tcx> { | |
32a655c1 | 1249 | let substs = self.ast_path_substs_for_ty(span, did, item_segment); |
04454e1e FG |
1250 | self.normalize_ty( |
1251 | span, | |
1252 | EarlyBinder(self.tcx().at(span).type_of(did)).subst(self.tcx(), substs), | |
1253 | ) | |
1a4d82fc JJ |
1254 | } |
1255 | ||
dfeec247 XL |
1256 | fn conv_object_ty_poly_trait_ref( |
1257 | &self, | |
32a655c1 | 1258 | span: Span, |
dfeec247 XL |
1259 | trait_bounds: &[hir::PolyTraitRef<'_>], |
1260 | lifetime: &hir::Lifetime, | |
3dfed10e | 1261 | borrowed: bool, |
f2b60f7d | 1262 | representation: DynKind, |
dfeec247 | 1263 | ) -> Ty<'tcx> { |
a7813a04 | 1264 | let tcx = self.tcx(); |
9e0c209e | 1265 | |
dc9dc135 XL |
1266 | let mut bounds = Bounds::default(); |
1267 | let mut potential_assoc_types = Vec::new(); | |
532ac7d7 | 1268 | let dummy_self = self.tcx().types.trait_object_dummy_self; |
416331ca | 1269 | for trait_bound in trait_bounds.iter().rev() { |
f9f354fc XL |
1270 | if let GenericArgCountResult { |
1271 | correct: | |
1272 | Err(GenericArgCountMismatch { invalid_args: cur_potential_assoc_types, .. }), | |
1273 | .. | |
1274 | } = self.instantiate_poly_trait_ref( | |
cdc7bbd5 XL |
1275 | &trait_bound.trait_ref, |
1276 | trait_bound.span, | |
94222f64 | 1277 | ty::BoundConstness::NotConst, |
416331ca XL |
1278 | dummy_self, |
1279 | &mut bounds, | |
cdc7bbd5 | 1280 | false, |
74b04a01 | 1281 | ) { |
5869c6ff | 1282 | potential_assoc_types.extend(cur_potential_assoc_types); |
74b04a01 | 1283 | } |
416331ca | 1284 | } |
dc9dc135 XL |
1285 | |
1286 | // Expand trait aliases recursively and check that only one regular (non-auto) trait | |
1287 | // is used and no 'maybe' bounds are used. | |
74b04a01 XL |
1288 | let expanded_traits = |
1289 | traits::expand_trait_aliases(tcx, bounds.trait_bounds.iter().map(|&(a, b, _)| (a, b))); | |
04454e1e FG |
1290 | let (mut auto_traits, regular_traits): (Vec<_>, Vec<_>) = expanded_traits |
1291 | .filter(|i| i.trait_ref().self_ty().skip_binder() == dummy_self) | |
1292 | .partition(|i| tcx.trait_is_auto(i.trait_ref().def_id())); | |
dc9dc135 XL |
1293 | if regular_traits.len() > 1 { |
1294 | let first_trait = ®ular_traits[0]; | |
1295 | let additional_trait = ®ular_traits[1]; | |
dfeec247 XL |
1296 | let mut err = struct_span_err!( |
1297 | tcx.sess, | |
1298 | additional_trait.bottom().1, | |
1299 | E0225, | |
dc9dc135 XL |
1300 | "only auto traits can be used as additional traits in a trait object" |
1301 | ); | |
dfeec247 XL |
1302 | additional_trait.label_with_exp_info( |
1303 | &mut err, | |
1304 | "additional non-auto trait", | |
1305 | "additional use", | |
1306 | ); | |
1307 | first_trait.label_with_exp_info(&mut err, "first non-auto trait", "first use"); | |
3dfed10e | 1308 | err.help(&format!( |
c295e0f8 | 1309 | "consider creating a new trait with all of these as supertraits and using that \ |
3dfed10e XL |
1310 | trait here instead: `trait NewTrait: {} {{}}`", |
1311 | regular_traits | |
1312 | .iter() | |
1313 | .map(|t| t.trait_ref().print_only_trait_path().to_string()) | |
1314 | .collect::<Vec<_>>() | |
1315 | .join(" + "), | |
1316 | )); | |
1317 | err.note( | |
1318 | "auto-traits like `Send` and `Sync` are traits that have special properties; \ | |
1319 | for more information on them, visit \ | |
1320 | <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits>", | |
1321 | ); | |
dc9dc135 | 1322 | err.emit(); |
7cac9316 XL |
1323 | } |
1324 | ||
dc9dc135 | 1325 | if regular_traits.is_empty() && auto_traits.is_empty() { |
04454e1e FG |
1326 | let trait_alias_span = bounds |
1327 | .trait_bounds | |
1328 | .iter() | |
1329 | .map(|&(trait_ref, _, _)| trait_ref.def_id()) | |
1330 | .find(|&trait_ref| tcx.is_trait_alias(trait_ref)) | |
1331 | .map(|trait_ref| tcx.def_span(trait_ref)); | |
1332 | tcx.sess.emit_err(TraitObjectDeclaredWithNoTraits { span, trait_alias_span }); | |
f035d41b | 1333 | return tcx.ty_error(); |
9e0c209e SL |
1334 | } |
1335 | ||
a1dfa0c6 XL |
1336 | // Check that there are no gross object safety violations; |
1337 | // most importantly, that the supertraits don't contain `Self`, | |
1338 | // to avoid ICEs. | |
dc9dc135 XL |
1339 | for item in ®ular_traits { |
1340 | let object_safety_violations = | |
dfeec247 | 1341 | astconv_object_safety_violations(tcx, item.trait_ref().def_id()); |
dc9dc135 | 1342 | if !object_safety_violations.is_empty() { |
dfeec247 XL |
1343 | report_object_safety_error( |
1344 | tcx, | |
dc9dc135 XL |
1345 | span, |
1346 | item.trait_ref().def_id(), | |
a2a8927a | 1347 | &object_safety_violations, |
dfeec247 XL |
1348 | ) |
1349 | .emit(); | |
f035d41b | 1350 | return tcx.ty_error(); |
dc9dc135 | 1351 | } |
a7813a04 XL |
1352 | } |
1353 | ||
a1dfa0c6 | 1354 | // Use a `BTreeSet` to keep output in a more consistent order. |
dfeec247 | 1355 | let mut associated_types: FxHashMap<Span, BTreeSet<DefId>> = FxHashMap::default(); |
b7449926 | 1356 | |
dfeec247 XL |
1357 | let regular_traits_refs_spans = bounds |
1358 | .trait_bounds | |
dc9dc135 | 1359 | .into_iter() |
dfeec247 | 1360 | .filter(|(trait_ref, _, _)| !tcx.trait_is_auto(trait_ref.def_id())); |
a7813a04 | 1361 | |
dfeec247 | 1362 | for (base_trait_ref, span, constness) in regular_traits_refs_spans { |
94222f64 | 1363 | assert_eq!(constness, ty::BoundConstness::NotConst); |
a7813a04 | 1364 | |
ba9703b0 | 1365 | for obligation in traits::elaborate_trait_ref(tcx, base_trait_ref) { |
dfeec247 XL |
1366 | debug!( |
1367 | "conv_object_ty_poly_trait_ref: observing object predicate `{:?}`", | |
ba9703b0 | 1368 | obligation.predicate |
a1dfa0c6 | 1369 | ); |
3dfed10e | 1370 | |
5869c6ff | 1371 | let bound_predicate = obligation.predicate.kind(); |
29967ef6 | 1372 | match bound_predicate.skip_binder() { |
94222f64 | 1373 | ty::PredicateKind::Trait(pred) => { |
29967ef6 | 1374 | let pred = bound_predicate.rebind(pred); |
dfeec247 XL |
1375 | associated_types.entry(span).or_default().extend( |
1376 | tcx.associated_items(pred.def_id()) | |
74b04a01 | 1377 | .in_definition_order() |
dfeec247 XL |
1378 | .filter(|item| item.kind == ty::AssocKind::Type) |
1379 | .map(|item| item.def_id), | |
1380 | ); | |
1381 | } | |
5869c6ff | 1382 | ty::PredicateKind::Projection(pred) => { |
29967ef6 | 1383 | let pred = bound_predicate.rebind(pred); |
dfeec247 XL |
1384 | // A `Self` within the original bound will be substituted with a |
1385 | // `trait_object_dummy_self`, so check for that. | |
f2b60f7d FG |
1386 | let references_self = match pred.skip_binder().term.unpack() { |
1387 | ty::TermKind::Ty(ty) => ty.walk().any(|arg| arg == dummy_self.into()), | |
1388 | ty::TermKind::Const(c) => { | |
1389 | c.ty().walk().any(|arg| arg == dummy_self.into()) | |
1390 | } | |
5099ac24 | 1391 | }; |
dfeec247 XL |
1392 | |
1393 | // If the projection output contains `Self`, force the user to | |
1394 | // elaborate it explicitly to avoid a lot of complexity. | |
1395 | // | |
5e7ed085 | 1396 | // The "classically useful" case is the following: |
dfeec247 XL |
1397 | // ``` |
1398 | // trait MyTrait: FnMut() -> <Self as MyTrait>::MyOutput { | |
1399 | // type MyOutput; | |
1400 | // } | |
1401 | // ``` | |
1402 | // | |
1403 | // Here, the user could theoretically write `dyn MyTrait<Output = X>`, | |
1404 | // but actually supporting that would "expand" to an infinitely-long type | |
1405 | // `fix $ τ → dyn MyTrait<MyOutput = X, Output = <τ as MyTrait>::MyOutput`. | |
1406 | // | |
1407 | // Instead, we force the user to write | |
1408 | // `dyn MyTrait<MyOutput = X, Output = X>`, which is uglier but works. See | |
1409 | // the discussion in #56288 for alternatives. | |
1410 | if !references_self { | |
1411 | // Include projections defined on supertraits. | |
1412 | bounds.projection_bounds.push((pred, span)); | |
1413 | } | |
a1dfa0c6 | 1414 | } |
dfeec247 | 1415 | _ => (), |
a1dfa0c6 XL |
1416 | } |
1417 | } | |
dfeec247 XL |
1418 | } |
1419 | ||
1420 | for (projection_bound, _) in &bounds.projection_bounds { | |
74b04a01 | 1421 | for def_ids in associated_types.values_mut() { |
dfeec247 | 1422 | def_ids.remove(&projection_bound.projection_def_id()); |
a1dfa0c6 | 1423 | } |
a7813a04 | 1424 | } |
9346a6ac | 1425 | |
dfeec247 XL |
1426 | self.complain_about_missing_associated_types( |
1427 | associated_types, | |
1428 | potential_assoc_types, | |
1429 | trait_bounds, | |
1430 | ); | |
1431 | ||
dc9dc135 XL |
1432 | // De-duplicate auto traits so that, e.g., `dyn Trait + Send + Send` is the same as |
1433 | // `dyn Trait + Send`. | |
6a06907d XL |
1434 | // We remove duplicates by inserting into a `FxHashSet` to avoid re-ordering |
1435 | // the bounds | |
1436 | let mut duplicates = FxHashSet::default(); | |
1437 | auto_traits.retain(|i| duplicates.insert(i.trait_ref().def_id())); | |
dc9dc135 XL |
1438 | debug!("regular_traits: {:?}", regular_traits); |
1439 | debug!("auto_traits: {:?}", auto_traits); | |
1440 | ||
532ac7d7 | 1441 | // Erase the `dummy_self` (`trait_object_dummy_self`) used above. |
6a06907d XL |
1442 | let existential_trait_refs = regular_traits.iter().map(|i| { |
1443 | i.trait_ref().map_bound(|trait_ref: ty::TraitRef<'tcx>| { | |
f2b60f7d FG |
1444 | assert_eq!(trait_ref.self_ty(), dummy_self); |
1445 | ||
1446 | // Verify that `dummy_self` did not leak inside default type parameters. This | |
1447 | // could not be done at path creation, since we need to see through trait aliases. | |
1448 | let mut missing_type_params = vec![]; | |
1449 | let mut references_self = false; | |
1450 | let generics = tcx.generics_of(trait_ref.def_id); | |
1451 | let substs: Vec<_> = trait_ref | |
1452 | .substs | |
1453 | .iter() | |
1454 | .enumerate() | |
1455 | .skip(1) // Remove `Self` for `ExistentialPredicate`. | |
1456 | .map(|(index, arg)| { | |
1457 | if arg == dummy_self.into() { | |
1458 | let param = &generics.params[index]; | |
1459 | missing_type_params.push(param.name); | |
1460 | return tcx.ty_error().into(); | |
1461 | } else if arg.walk().any(|arg| arg == dummy_self.into()) { | |
1462 | references_self = true; | |
1463 | return tcx.ty_error().into(); | |
1464 | } | |
1465 | arg | |
1466 | }) | |
1467 | .collect(); | |
1468 | let substs = tcx.intern_substs(&substs[..]); | |
1469 | ||
1470 | let span = i.bottom().1; | |
1471 | let empty_generic_args = trait_bounds.iter().any(|hir_bound| { | |
1472 | hir_bound.trait_ref.path.res == Res::Def(DefKind::Trait, trait_ref.def_id) | |
1473 | && hir_bound.span.contains(span) | |
1474 | }); | |
1475 | self.complain_about_missing_type_params( | |
1476 | missing_type_params, | |
1477 | trait_ref.def_id, | |
1478 | span, | |
1479 | empty_generic_args, | |
1480 | ); | |
1481 | ||
1482 | if references_self { | |
1483 | let def_id = i.bottom().0.def_id(); | |
1484 | let mut err = struct_span_err!( | |
1485 | tcx.sess, | |
1486 | i.bottom().1, | |
1487 | E0038, | |
1488 | "the {} `{}` cannot be made into an object", | |
1489 | tcx.def_kind(def_id).descr(def_id), | |
1490 | tcx.item_name(def_id), | |
1491 | ); | |
1492 | err.note( | |
1493 | rustc_middle::traits::ObjectSafetyViolation::SupertraitSelf(smallvec![]) | |
1494 | .error_msg(), | |
6a06907d | 1495 | ); |
f2b60f7d | 1496 | err.emit(); |
6a06907d | 1497 | } |
f2b60f7d FG |
1498 | |
1499 | ty::ExistentialTraitRef { def_id: trait_ref.def_id, substs } | |
6a06907d XL |
1500 | }) |
1501 | }); | |
f2b60f7d | 1502 | |
dc9dc135 | 1503 | let existential_projections = bounds.projection_bounds.iter().map(|(bound, _)| { |
f2b60f7d FG |
1504 | bound.map_bound(|mut b| { |
1505 | assert_eq!(b.projection_ty.self_ty(), dummy_self); | |
1506 | ||
1507 | // Like for trait refs, verify that `dummy_self` did not leak inside default type | |
1508 | // parameters. | |
1509 | let references_self = b.projection_ty.substs.iter().skip(1).any(|arg| { | |
1510 | if arg.walk().any(|arg| arg == dummy_self.into()) { | |
1511 | return true; | |
1512 | } | |
1513 | false | |
1514 | }); | |
1515 | if references_self { | |
1516 | tcx.sess | |
1517 | .delay_span_bug(span, "trait object projection bounds reference `Self`"); | |
1518 | let substs: Vec<_> = b | |
1519 | .projection_ty | |
1520 | .substs | |
1521 | .iter() | |
1522 | .map(|arg| { | |
1523 | if arg.walk().any(|arg| arg == dummy_self.into()) { | |
1524 | return tcx.ty_error().into(); | |
1525 | } | |
1526 | arg | |
1527 | }) | |
1528 | .collect(); | |
1529 | b.projection_ty.substs = tcx.intern_substs(&substs[..]); | |
a1dfa0c6 | 1530 | } |
f2b60f7d | 1531 | |
6a06907d | 1532 | ty::ExistentialProjection::erase_self_ty(tcx, b) |
a1dfa0c6 XL |
1533 | }) |
1534 | }); | |
1535 | ||
5869c6ff XL |
1536 | let regular_trait_predicates = existential_trait_refs |
1537 | .map(|trait_ref| trait_ref.map_bound(ty::ExistentialPredicate::Trait)); | |
fc512014 XL |
1538 | let auto_trait_predicates = auto_traits.into_iter().map(|trait_ref| { |
1539 | ty::Binder::dummy(ty::ExistentialPredicate::AutoTrait(trait_ref.trait_ref().def_id())) | |
1540 | }); | |
17df50a5 XL |
1541 | // N.b. principal, projections, auto traits |
1542 | // FIXME: This is actually wrong with multiple principals in regards to symbol mangling | |
dfeec247 | 1543 | let mut v = regular_trait_predicates |
dfeec247 | 1544 | .chain( |
5869c6ff | 1545 | existential_projections.map(|x| x.map_bound(ty::ExistentialPredicate::Projection)), |
dfeec247 | 1546 | ) |
17df50a5 | 1547 | .chain(auto_trait_predicates) |
b7449926 | 1548 | .collect::<SmallVec<[_; 8]>>(); |
fc512014 | 1549 | v.sort_by(|a, b| a.skip_binder().stable_cmp(tcx, &b.skip_binder())); |
0731742a | 1550 | v.dedup(); |
fc512014 | 1551 | let existential_predicates = tcx.mk_poly_existential_predicates(v.into_iter()); |
476ff2be | 1552 | |
a1dfa0c6 | 1553 | // Use explicitly-specified region bound. |
32a655c1 SL |
1554 | let region_bound = if !lifetime.is_elided() { |
1555 | self.ast_region_to_region(lifetime, None) | |
1556 | } else { | |
1557 | self.compute_object_lifetime_bound(span, existential_predicates).unwrap_or_else(|| { | |
9fa01778 | 1558 | if tcx.named_region(lifetime.hir_id).is_some() { |
32a655c1 SL |
1559 | self.ast_region_to_region(lifetime, None) |
1560 | } else { | |
dc9dc135 | 1561 | self.re_infer(None, span).unwrap_or_else(|| { |
3dfed10e | 1562 | let mut err = struct_span_err!( |
dfeec247 XL |
1563 | tcx.sess, |
1564 | span, | |
1565 | E0228, | |
dc9dc135 | 1566 | "the lifetime bound for this object type cannot be deduced \ |
dfeec247 | 1567 | from context; please supply an explicit bound" |
3dfed10e XL |
1568 | ); |
1569 | if borrowed { | |
1570 | // We will have already emitted an error E0106 complaining about a | |
1571 | // missing named lifetime in `&dyn Trait`, so we elide this one. | |
1572 | err.delay_as_bug(); | |
1573 | } else { | |
1574 | err.emit(); | |
1575 | } | |
48663c56 | 1576 | tcx.lifetimes.re_static |
32a655c1 SL |
1577 | }) |
1578 | } | |
1579 | }) | |
476ff2be | 1580 | }; |
476ff2be SL |
1581 | debug!("region_bound: {:?}", region_bound); |
1582 | ||
f2b60f7d | 1583 | let ty = tcx.mk_dynamic(existential_predicates, region_bound, representation); |
9e0c209e SL |
1584 | debug!("trait_object_type: {:?}", ty); |
1585 | ty | |
9346a6ac AL |
1586 | } |
1587 | ||
48663c56 XL |
1588 | fn report_ambiguous_associated_type( |
1589 | &self, | |
1590 | span: Span, | |
1591 | type_str: &str, | |
1592 | trait_str: &str, | |
f9f354fc | 1593 | name: Symbol, |
5e7ed085 | 1594 | ) -> ErrorGuaranteed { |
48663c56 | 1595 | let mut err = struct_span_err!(self.tcx().sess, span, E0223, "ambiguous associated type"); |
923072b8 FG |
1596 | if self |
1597 | .tcx() | |
1598 | .resolutions(()) | |
1599 | .confused_type_with_std_module | |
1600 | .keys() | |
1601 | .any(|full_span| full_span.contains(span)) | |
1602 | { | |
48663c56 | 1603 | err.span_suggestion( |
923072b8 | 1604 | span.shrink_to_lo(), |
48663c56 | 1605 | "you are looking for the module in `std`, not the primitive type", |
923072b8 | 1606 | "std::", |
48663c56 XL |
1607 | Applicability::MachineApplicable, |
1608 | ); | |
1609 | } else { | |
1610 | err.span_suggestion( | |
dfeec247 XL |
1611 | span, |
1612 | "use fully-qualified syntax", | |
1613 | format!("<{} as {}>::{}", type_str, trait_str, name), | |
1614 | Applicability::HasPlaceholders, | |
48663c56 XL |
1615 | ); |
1616 | } | |
5e7ed085 | 1617 | err.emit() |
a7813a04 | 1618 | } |
9346a6ac | 1619 | |
a7813a04 | 1620 | // Search for a bound on a type parameter which includes the associated item |
dc9dc135 | 1621 | // given by `assoc_name`. `ty_param_def_id` is the `DefId` of the type parameter |
8bb4bdeb | 1622 | // This function will fail if there are no suitable bounds or there is |
a7813a04 | 1623 | // any ambiguity. |
dfeec247 XL |
1624 | fn find_bound_for_assoc_item( |
1625 | &self, | |
f9f354fc XL |
1626 | ty_param_def_id: LocalDefId, |
1627 | assoc_name: Ident, | |
dfeec247 | 1628 | span: Span, |
5e7ed085 | 1629 | ) -> Result<ty::PolyTraitRef<'tcx>, ErrorGuaranteed> { |
a7813a04 | 1630 | let tcx = self.tcx(); |
c34b1796 | 1631 | |
416331ca XL |
1632 | debug!( |
1633 | "find_bound_for_assoc_item(ty_param_def_id={:?}, assoc_name={:?}, span={:?})", | |
dfeec247 | 1634 | ty_param_def_id, assoc_name, span, |
416331ca XL |
1635 | ); |
1636 | ||
6a06907d XL |
1637 | let predicates = &self |
1638 | .get_type_parameter_bounds(span, ty_param_def_id.to_def_id(), assoc_name) | |
1639 | .predicates; | |
416331ca XL |
1640 | |
1641 | debug!("find_bound_for_assoc_item: predicates={:#?}", predicates); | |
1642 | ||
04454e1e | 1643 | let param_name = tcx.hir().ty_param_name(ty_param_def_id); |
dfeec247 XL |
1644 | self.one_bound_for_assoc_type( |
1645 | || { | |
6a06907d | 1646 | traits::transitive_bounds_that_define_assoc_type( |
dfeec247 | 1647 | tcx, |
fc512014 | 1648 | predicates.iter().filter_map(|(p, _)| { |
a2a8927a | 1649 | Some(p.to_opt_poly_trait_pred()?.map_bound(|t| t.trait_ref)) |
fc512014 | 1650 | }), |
6a06907d | 1651 | assoc_name, |
dfeec247 XL |
1652 | ) |
1653 | }, | |
1654 | || param_name.to_string(), | |
1655 | assoc_name, | |
1656 | span, | |
1657 | || None, | |
1658 | ) | |
9346a6ac AL |
1659 | } |
1660 | ||
a1dfa0c6 | 1661 | // Checks that `bounds` contains exactly one element and reports appropriate |
a7813a04 | 1662 | // errors otherwise. |
dfeec247 XL |
1663 | fn one_bound_for_assoc_type<I>( |
1664 | &self, | |
1665 | all_candidates: impl Fn() -> I, | |
1666 | ty_param_name: impl Fn() -> String, | |
f9f354fc | 1667 | assoc_name: Ident, |
dfeec247 XL |
1668 | span: Span, |
1669 | is_equality: impl Fn() -> Option<String>, | |
5e7ed085 | 1670 | ) -> Result<ty::PolyTraitRef<'tcx>, ErrorGuaranteed> |
dfeec247 XL |
1671 | where |
1672 | I: Iterator<Item = ty::PolyTraitRef<'tcx>>, | |
a7813a04 | 1673 | { |
dfeec247 XL |
1674 | let mut matching_candidates = all_candidates() |
1675 | .filter(|r| self.trait_defines_associated_type_named(r.def_id(), assoc_name)); | |
5099ac24 FG |
1676 | let mut const_candidates = all_candidates() |
1677 | .filter(|r| self.trait_defines_associated_const_named(r.def_id(), assoc_name)); | |
dfeec247 | 1678 | |
5099ac24 FG |
1679 | let (bound, next_cand) = match (matching_candidates.next(), const_candidates.next()) { |
1680 | (Some(bound), _) => (bound, matching_candidates.next()), | |
1681 | (None, Some(bound)) => (bound, const_candidates.next()), | |
1682 | (None, None) => { | |
5e7ed085 | 1683 | let reported = self.complain_about_assoc_type_not_found( |
dfeec247 XL |
1684 | all_candidates, |
1685 | &ty_param_name(), | |
1686 | assoc_name, | |
1687 | span, | |
1688 | ); | |
5e7ed085 | 1689 | return Err(reported); |
476ff2be SL |
1690 | } |
1691 | }; | |
416331ca XL |
1692 | debug!("one_bound_for_assoc_type: bound = {:?}", bound); |
1693 | ||
5099ac24 | 1694 | if let Some(bound2) = next_cand { |
416331ca XL |
1695 | debug!("one_bound_for_assoc_type: bound2 = {:?}", bound2); |
1696 | ||
dfeec247 | 1697 | let is_equality = is_equality(); |
a2a8927a | 1698 | let bounds = IntoIterator::into_iter([bound, bound2]).chain(matching_candidates); |
dfeec247 XL |
1699 | let mut err = if is_equality.is_some() { |
1700 | // More specific Error Index entry. | |
1701 | struct_span_err!( | |
1702 | self.tcx().sess, | |
1703 | span, | |
1704 | E0222, | |
1705 | "ambiguous associated type `{}` in bounds of `{}`", | |
1706 | assoc_name, | |
1707 | ty_param_name() | |
1708 | ) | |
1709 | } else { | |
1710 | struct_span_err!( | |
1711 | self.tcx().sess, | |
1712 | span, | |
1713 | E0221, | |
1714 | "ambiguous associated type `{}` in bounds of `{}`", | |
1715 | assoc_name, | |
1716 | ty_param_name() | |
1717 | ) | |
1718 | }; | |
7cac9316 | 1719 | err.span_label(span, format!("ambiguous associated type `{}`", assoc_name)); |
9346a6ac | 1720 | |
dfeec247 | 1721 | let mut where_bounds = vec![]; |
476ff2be | 1722 | for bound in bounds { |
74b04a01 | 1723 | let bound_id = bound.def_id(); |
dfeec247 XL |
1724 | let bound_span = self |
1725 | .tcx() | |
74b04a01 XL |
1726 | .associated_items(bound_id) |
1727 | .find_by_name_and_kind(self.tcx(), assoc_name, ty::AssocKind::Type, bound_id) | |
416331ca | 1728 | .and_then(|item| self.tcx().hir().span_if_local(item.def_id)); |
476ff2be | 1729 | |
dfeec247 XL |
1730 | if let Some(bound_span) = bound_span { |
1731 | err.span_label( | |
1732 | bound_span, | |
1733 | format!( | |
1734 | "ambiguous `{}` from `{}`", | |
1735 | assoc_name, | |
1736 | bound.print_only_trait_path(), | |
1737 | ), | |
1738 | ); | |
1739 | if let Some(constraint) = &is_equality { | |
1740 | where_bounds.push(format!( | |
1741 | " T: {trait}::{assoc} = {constraint}", | |
1742 | trait=bound.print_only_trait_path(), | |
1743 | assoc=assoc_name, | |
1744 | constraint=constraint, | |
1745 | )); | |
1746 | } else { | |
c295e0f8 XL |
1747 | err.span_suggestion_verbose( |
1748 | span.with_hi(assoc_name.span.lo()), | |
dfeec247 XL |
1749 | "use fully qualified syntax to disambiguate", |
1750 | format!( | |
c295e0f8 | 1751 | "<{} as {}>::", |
dfeec247 XL |
1752 | ty_param_name(), |
1753 | bound.print_only_trait_path(), | |
dfeec247 XL |
1754 | ), |
1755 | Applicability::MaybeIncorrect, | |
1756 | ); | |
1757 | } | |
c30ab7b3 | 1758 | } else { |
dfeec247 XL |
1759 | err.note(&format!( |
1760 | "associated type `{}` could derive from `{}`", | |
1761 | ty_param_name(), | |
1762 | bound.print_only_trait_path(), | |
1763 | )); | |
c30ab7b3 | 1764 | } |
a7813a04 | 1765 | } |
dfeec247 XL |
1766 | if !where_bounds.is_empty() { |
1767 | err.help(&format!( | |
1768 | "consider introducing a new type parameter `T` and adding `where` constraints:\ | |
1769 | \n where\n T: {},\n{}", | |
1770 | ty_param_name(), | |
1771 | where_bounds.join(",\n"), | |
1772 | )); | |
1773 | } | |
5e7ed085 | 1774 | let reported = err.emit(); |
dfeec247 | 1775 | if !where_bounds.is_empty() { |
5e7ed085 | 1776 | return Err(reported); |
dfeec247 | 1777 | } |
9346a6ac | 1778 | } |
5099ac24 | 1779 | |
ba9703b0 | 1780 | Ok(bound) |
9346a6ac AL |
1781 | } |
1782 | ||
a7813a04 | 1783 | // Create a type from a path to an associated type. |
9fa01778 | 1784 | // For a path `A::B::C::D`, `qself_ty` and `qself_def` are the type and def for `A::B::C` |
a1dfa0c6 | 1785 | // and item_segment is the path segment for `D`. We return a type and a def for |
a7813a04 | 1786 | // the whole path. |
9fa01778 | 1787 | // Will fail except for `T::A` and `Self::A`; i.e., if `qself_ty`/`qself_def` are not a type |
a1dfa0c6 | 1788 | // parameter or `Self`. |
6a06907d | 1789 | // NOTE: When this function starts resolving `Trait::AssocTy` successfully |
5e7ed085 | 1790 | // it should also start reporting the `BARE_TRAIT_OBJECTS` lint. |
9fa01778 XL |
1791 | pub fn associated_path_to_ty( |
1792 | &self, | |
532ac7d7 | 1793 | hir_ref_id: hir::HirId, |
9fa01778 XL |
1794 | span: Span, |
1795 | qself_ty: Ty<'tcx>, | |
923072b8 | 1796 | qself: &hir::Ty<'_>, |
dfeec247 | 1797 | assoc_segment: &hir::PathSegment<'_>, |
9fa01778 | 1798 | permit_variants: bool, |
5e7ed085 | 1799 | ) -> Result<(Ty<'tcx>, DefKind, DefId), ErrorGuaranteed> { |
a7813a04 | 1800 | let tcx = self.tcx(); |
9fa01778 | 1801 | let assoc_ident = assoc_segment.ident; |
923072b8 FG |
1802 | let qself_res = if let hir::TyKind::Path(hir::QPath::Resolved(_, ref path)) = qself.kind { |
1803 | path.res | |
1804 | } else { | |
1805 | Res::Err | |
1806 | }; | |
a7813a04 | 1807 | |
9fa01778 | 1808 | debug!("associated_path_to_ty: {:?}::{}", qself_ty, assoc_ident); |
a7813a04 | 1809 | |
9fa01778 XL |
1810 | // Check if we have an enum variant. |
1811 | let mut variant_resolution = None; | |
1b1a35ee | 1812 | if let ty::Adt(adt_def, _) = qself_ty.kind() { |
9fa01778 | 1813 | if adt_def.is_enum() { |
dfeec247 | 1814 | let variant_def = adt_def |
5e7ed085 | 1815 | .variants() |
dfeec247 | 1816 | .iter() |
5e7ed085 | 1817 | .find(|vd| tcx.hygienic_eq(assoc_ident, vd.ident(tcx), adt_def.did())); |
9fa01778 | 1818 | if let Some(variant_def) = variant_def { |
9fa01778 | 1819 | if permit_variants { |
17df50a5 | 1820 | tcx.check_stability(variant_def.def_id, Some(hir_ref_id), span, None); |
923072b8 FG |
1821 | self.prohibit_generics(slice::from_ref(assoc_segment).iter(), |err| { |
1822 | err.note("enum variants can't have type parameters"); | |
1823 | let type_name = tcx.item_name(adt_def.did()); | |
1824 | let msg = format!( | |
1825 | "you might have meant to specity type parameters on enum \ | |
1826 | `{type_name}`" | |
1827 | ); | |
1828 | let Some(args) = assoc_segment.args else { return; }; | |
1829 | // Get the span of the generics args *including* the leading `::`. | |
1830 | let args_span = assoc_segment.ident.span.shrink_to_hi().to(args.span_ext); | |
1831 | if tcx.generics_of(adt_def.did()).count() == 0 { | |
1832 | // FIXME(estebank): we could also verify that the arguments being | |
1833 | // work for the `enum`, instead of just looking if it takes *any*. | |
1834 | err.span_suggestion_verbose( | |
1835 | args_span, | |
1836 | &format!("{type_name} doesn't have generic parameters"), | |
1837 | "", | |
1838 | Applicability::MachineApplicable, | |
1839 | ); | |
1840 | return; | |
1841 | } | |
1842 | let Ok(snippet) = tcx.sess.source_map().span_to_snippet(args_span) else { | |
1843 | err.note(&msg); | |
1844 | return; | |
1845 | }; | |
1846 | let (qself_sugg_span, is_self) = if let hir::TyKind::Path( | |
1847 | hir::QPath::Resolved(_, ref path) | |
1848 | ) = qself.kind { | |
1849 | // If the path segment already has type params, we want to overwrite | |
1850 | // them. | |
1851 | match &path.segments[..] { | |
1852 | // `segment` is the previous to last element on the path, | |
1853 | // which would normally be the `enum` itself, while the last | |
1854 | // `_` `PathSegment` corresponds to the variant. | |
1855 | [.., hir::PathSegment { | |
1856 | ident, | |
1857 | args, | |
f2b60f7d | 1858 | res: Res::Def(DefKind::Enum, _), |
923072b8 FG |
1859 | .. |
1860 | }, _] => ( | |
1861 | // We need to include the `::` in `Type::Variant::<Args>` | |
1862 | // to point the span to `::<Args>`, not just `<Args>`. | |
1863 | ident.span.shrink_to_hi().to(args.map_or( | |
1864 | ident.span.shrink_to_hi(), | |
1865 | |a| a.span_ext)), | |
1866 | false, | |
1867 | ), | |
1868 | [segment] => ( | |
1869 | // We need to include the `::` in `Type::Variant::<Args>` | |
1870 | // to point the span to `::<Args>`, not just `<Args>`. | |
1871 | segment.ident.span.shrink_to_hi().to(segment.args.map_or( | |
1872 | segment.ident.span.shrink_to_hi(), | |
1873 | |a| a.span_ext)), | |
1874 | kw::SelfUpper == segment.ident.name, | |
1875 | ), | |
1876 | _ => { | |
1877 | err.note(&msg); | |
1878 | return; | |
1879 | } | |
1880 | } | |
1881 | } else { | |
1882 | err.note(&msg); | |
1883 | return; | |
1884 | }; | |
1885 | let suggestion = vec![ | |
1886 | if is_self { | |
1887 | // Account for people writing `Self::Variant::<Args>`, where | |
1888 | // `Self` is the enum, and suggest replacing `Self` with the | |
1889 | // appropriate type: `Type::<Args>::Variant`. | |
1890 | (qself.span, format!("{type_name}{snippet}")) | |
1891 | } else { | |
1892 | (qself_sugg_span, snippet) | |
1893 | }, | |
1894 | (args_span, String::new()), | |
1895 | ]; | |
1896 | err.multipart_suggestion_verbose( | |
1897 | &msg, | |
1898 | suggestion, | |
1899 | Applicability::MaybeIncorrect, | |
1900 | ); | |
1901 | }); | |
48663c56 | 1902 | return Ok((qself_ty, DefKind::Variant, variant_def.def_id)); |
9fa01778 | 1903 | } else { |
48663c56 | 1904 | variant_resolution = Some(variant_def.def_id); |
9fa01778 XL |
1905 | } |
1906 | } | |
1907 | } | |
1908 | } | |
a7813a04 XL |
1909 | |
1910 | // Find the type of the associated item, and the trait where the associated | |
1911 | // item is declared. | |
1b1a35ee | 1912 | let bound = match (&qself_ty.kind(), qself_res) { |
5099ac24 | 1913 | (_, Res::SelfTy { trait_: Some(_), alias_to: Some((impl_def_id, _)) }) => { |
0731742a | 1914 | // `Self` in an impl of a trait -- we have a concrete self type and a |
a7813a04 | 1915 | // trait reference. |
5e7ed085 FG |
1916 | let Some(trait_ref) = tcx.impl_trait_ref(impl_def_id) else { |
1917 | // A cycle error occurred, most likely. | |
1918 | let guar = tcx.sess.delay_span_bug(span, "expected cycle error"); | |
1919 | return Err(guar); | |
8bb4bdeb XL |
1920 | }; |
1921 | ||
dfeec247 | 1922 | self.one_bound_for_assoc_type( |
136023e0 | 1923 | || traits::supertraits(tcx, ty::Binder::dummy(trait_ref)), |
dfeec247 XL |
1924 | || "Self".to_string(), |
1925 | assoc_ident, | |
1926 | span, | |
1927 | || None, | |
1928 | )? | |
c1a9b12d | 1929 | } |
ba9703b0 XL |
1930 | ( |
1931 | &ty::Param(_), | |
5099ac24 FG |
1932 | Res::SelfTy { trait_: Some(param_did), alias_to: None } |
1933 | | Res::Def(DefKind::TyParam, param_did), | |
f9f354fc | 1934 | ) => self.find_bound_for_assoc_item(param_did.expect_local(), assoc_ident, span)?, |
9fa01778 | 1935 | _ => { |
5e7ed085 | 1936 | let reported = if variant_resolution.is_some() { |
9fa01778 XL |
1937 | // Variant in type position |
1938 | let msg = format!("expected type, found variant `{}`", assoc_ident); | |
5e7ed085 | 1939 | tcx.sess.span_err(span, &msg) |
9fa01778 | 1940 | } else if qself_ty.is_enum() { |
dfeec247 XL |
1941 | let mut err = struct_span_err!( |
1942 | tcx.sess, | |
48663c56 | 1943 | assoc_ident.span, |
dfeec247 XL |
1944 | E0599, |
1945 | "no variant named `{}` found for enum `{}`", | |
1946 | assoc_ident, | |
1947 | qself_ty, | |
a1dfa0c6 | 1948 | ); |
48663c56 | 1949 | |
9fa01778 XL |
1950 | let adt_def = qself_ty.ty_adt_def().expect("enum is not an ADT"); |
1951 | if let Some(suggested_name) = find_best_match_for_name( | |
fc512014 | 1952 | &adt_def |
5e7ed085 | 1953 | .variants() |
fc512014 | 1954 | .iter() |
5099ac24 | 1955 | .map(|variant| variant.name) |
fc512014 | 1956 | .collect::<Vec<Symbol>>(), |
3dfed10e | 1957 | assoc_ident.name, |
9fa01778 XL |
1958 | None, |
1959 | ) { | |
1960 | err.span_suggestion( | |
48663c56 XL |
1961 | assoc_ident.span, |
1962 | "there is a variant with a similar name", | |
923072b8 | 1963 | suggested_name, |
9fa01778 XL |
1964 | Applicability::MaybeIncorrect, |
1965 | ); | |
1966 | } else { | |
416331ca XL |
1967 | err.span_label( |
1968 | assoc_ident.span, | |
1969 | format!("variant not found in `{}`", qself_ty), | |
1970 | ); | |
48663c56 XL |
1971 | } |
1972 | ||
5e7ed085 | 1973 | if let Some(sp) = tcx.hir().span_if_local(adt_def.did()) { |
48663c56 | 1974 | err.span_label(sp, format!("variant `{}` not found here", assoc_ident)); |
9fa01778 | 1975 | } |
48663c56 | 1976 | |
5e7ed085 FG |
1977 | err.emit() |
1978 | } else if let Some(reported) = qself_ty.error_reported() { | |
1979 | reported | |
1980 | } else { | |
9fa01778 | 1981 | // Don't print `TyErr` to the user. |
48663c56 XL |
1982 | self.report_ambiguous_associated_type( |
1983 | span, | |
1984 | &qself_ty.to_string(), | |
1985 | "Trait", | |
e1599b0c | 1986 | assoc_ident.name, |
5e7ed085 FG |
1987 | ) |
1988 | }; | |
1989 | return Err(reported); | |
9346a6ac | 1990 | } |
a7813a04 | 1991 | }; |
c34b1796 | 1992 | |
83c7162d | 1993 | let trait_did = bound.def_id(); |
dc9dc135 XL |
1994 | let (assoc_ident, def_scope) = |
1995 | tcx.adjust_ident_and_get_scope(assoc_ident, trait_did, hir_ref_id); | |
74b04a01 | 1996 | |
ba9703b0 | 1997 | // We have already adjusted the item name above, so compare with `ident.normalize_to_macros_2_0()` instead |
74b04a01 | 1998 | // of calling `filter_by_name_and_kind`. |
5099ac24 FG |
1999 | let item = tcx.associated_items(trait_did).in_definition_order().find(|i| { |
2000 | i.kind.namespace() == Namespace::TypeNS | |
2001 | && i.ident(tcx).normalize_to_macros_2_0() == assoc_ident | |
2002 | }); | |
2003 | // Assume that if it's not matched, there must be a const defined with the same name | |
2004 | // but it was used in a type position. | |
2005 | let Some(item) = item else { | |
2006 | let msg = format!("found associated const `{assoc_ident}` when type was expected"); | |
5e7ed085 FG |
2007 | let guar = tcx.sess.struct_span_err(span, &msg).emit(); |
2008 | return Err(guar); | |
5099ac24 | 2009 | }; |
041b39d2 | 2010 | |
dfeec247 | 2011 | let ty = self.projected_ty_from_poly_trait_ref(span, item.def_id, assoc_segment, bound); |
041b39d2 XL |
2012 | let ty = self.normalize_ty(span, ty); |
2013 | ||
dc9dc135 | 2014 | let kind = DefKind::AssocTy; |
064997fb | 2015 | if !item.visibility(tcx).is_accessible_from(def_scope, tcx) { |
ba9703b0 XL |
2016 | let kind = kind.descr(item.def_id); |
2017 | let msg = format!("{} `{}` is private", kind, assoc_ident); | |
2018 | tcx.sess | |
2019 | .struct_span_err(span, &msg) | |
2020 | .span_label(span, &format!("private {}", kind)) | |
2021 | .emit(); | |
7cac9316 | 2022 | } |
17df50a5 | 2023 | tcx.check_stability(item.def_id, Some(hir_ref_id), span, None); |
7cac9316 | 2024 | |
48663c56 | 2025 | if let Some(variant_def_id) = variant_resolution { |
74b04a01 XL |
2026 | tcx.struct_span_lint_hir(AMBIGUOUS_ASSOCIATED_ITEMS, hir_ref_id, span, |lint| { |
2027 | let mut err = lint.build("ambiguous associated item"); | |
2028 | let mut could_refer_to = |kind: DefKind, def_id, also| { | |
2029 | let note_msg = format!( | |
2030 | "`{}` could{} refer to the {} defined here", | |
2031 | assoc_ident, | |
2032 | also, | |
2033 | kind.descr(def_id) | |
2034 | ); | |
2035 | err.span_note(tcx.def_span(def_id), ¬e_msg); | |
2036 | }; | |
9fa01778 | 2037 | |
74b04a01 XL |
2038 | could_refer_to(DefKind::Variant, variant_def_id, ""); |
2039 | could_refer_to(kind, item.def_id, " also"); | |
2040 | ||
2041 | err.span_suggestion( | |
2042 | span, | |
2043 | "use fully-qualified syntax", | |
2044 | format!("<{} as {}>::{}", qself_ty, tcx.item_name(trait_did), assoc_ident), | |
2045 | Applicability::MachineApplicable, | |
dfeec247 | 2046 | ); |
9fa01778 | 2047 | |
74b04a01 XL |
2048 | err.emit(); |
2049 | }); | |
9fa01778 | 2050 | } |
48663c56 | 2051 | Ok((ty, kind, item.def_id)) |
a7813a04 | 2052 | } |
1a4d82fc | 2053 | |
dfeec247 XL |
2054 | fn qpath_to_ty( |
2055 | &self, | |
2056 | span: Span, | |
2057 | opt_self_ty: Option<Ty<'tcx>>, | |
2058 | item_def_id: DefId, | |
2059 | trait_segment: &hir::PathSegment<'_>, | |
2060 | item_segment: &hir::PathSegment<'_>, | |
2061 | ) -> Ty<'tcx> { | |
a7813a04 | 2062 | let tcx = self.tcx(); |
60c5eb7d | 2063 | |
04454e1e | 2064 | let trait_def_id = tcx.parent(item_def_id); |
1a4d82fc | 2065 | |
60c5eb7d XL |
2066 | debug!("qpath_to_ty: trait_def_id={:?}", trait_def_id); |
2067 | ||
3c0e092e | 2068 | let Some(self_ty) = opt_self_ty else { |
532ac7d7 | 2069 | let path_str = tcx.def_path_str(trait_def_id); |
60c5eb7d XL |
2070 | |
2071 | let def_id = self.item_def_id(); | |
2072 | ||
2073 | debug!("qpath_to_ty: self.item_def_id()={:?}", def_id); | |
2074 | ||
dfeec247 | 2075 | let parent_def_id = def_id |
f9f354fc | 2076 | .and_then(|def_id| { |
3dfed10e | 2077 | def_id.as_local().map(|def_id| tcx.hir().local_def_id_to_hir_id(def_id)) |
f9f354fc | 2078 | }) |
5099ac24 | 2079 | .map(|hir_id| tcx.hir().get_parent_item(hir_id).to_def_id()); |
60c5eb7d XL |
2080 | |
2081 | debug!("qpath_to_ty: parent_def_id={:?}", parent_def_id); | |
2082 | ||
2083 | // If the trait in segment is the same as the trait defining the item, | |
2084 | // use the `<Self as ..>` syntax in the error. | |
2085 | let is_part_of_self_trait_constraints = def_id == Some(trait_def_id); | |
2086 | let is_part_of_fn_in_self_trait = parent_def_id == Some(trait_def_id); | |
2087 | ||
2088 | let type_name = if is_part_of_self_trait_constraints || is_part_of_fn_in_self_trait { | |
2089 | "Self" | |
2090 | } else { | |
2091 | "Type" | |
2092 | }; | |
2093 | ||
48663c56 XL |
2094 | self.report_ambiguous_associated_type( |
2095 | span, | |
60c5eb7d | 2096 | type_name, |
48663c56 | 2097 | &path_str, |
e1599b0c | 2098 | item_segment.ident.name, |
48663c56 | 2099 | ); |
f035d41b | 2100 | return tcx.ty_error(); |
a7813a04 | 2101 | }; |
1a4d82fc | 2102 | |
a7813a04 | 2103 | debug!("qpath_to_ty: self_type={:?}", self_ty); |
1a4d82fc | 2104 | |
5099ac24 FG |
2105 | let trait_ref = |
2106 | self.ast_path_to_mono_trait_ref(span, trait_def_id, self_ty, trait_segment, false); | |
dfeec247 XL |
2107 | |
2108 | let item_substs = self.create_substs_for_associated_item( | |
2109 | tcx, | |
2110 | span, | |
2111 | item_def_id, | |
2112 | item_segment, | |
2113 | trait_ref.substs, | |
2114 | ); | |
1a4d82fc | 2115 | |
a7813a04 | 2116 | debug!("qpath_to_ty: trait_ref={:?}", trait_ref); |
85aaf69f | 2117 | |
dfeec247 | 2118 | self.normalize_ty(span, tcx.mk_projection(item_def_id, item_substs)) |
8bb4bdeb XL |
2119 | } |
2120 | ||
923072b8 | 2121 | pub fn prohibit_generics<'a>( |
dfeec247 | 2122 | &self, |
923072b8 | 2123 | segments: impl Iterator<Item = &'a hir::PathSegment<'a>> + Clone, |
f2b60f7d | 2124 | extend: impl Fn(&mut Diagnostic), |
dfeec247 | 2125 | ) -> bool { |
923072b8 FG |
2126 | let args = segments.clone().flat_map(|segment| segment.args().args); |
2127 | ||
2128 | let (lt, ty, ct, inf) = | |
2129 | args.clone().fold((false, false, false, false), |(lt, ty, ct, inf), arg| match arg { | |
2130 | hir::GenericArg::Lifetime(_) => (true, ty, ct, inf), | |
2131 | hir::GenericArg::Type(_) => (lt, true, ct, inf), | |
2132 | hir::GenericArg::Const(_) => (lt, ty, true, inf), | |
2133 | hir::GenericArg::Infer(_) => (lt, ty, ct, true), | |
2134 | }); | |
2135 | let mut emitted = false; | |
2136 | if lt || ty || ct || inf { | |
2137 | let types_and_spans: Vec<_> = segments | |
2138 | .clone() | |
2139 | .flat_map(|segment| { | |
f2b60f7d FG |
2140 | if segment.args().args.is_empty() { |
2141 | None | |
2142 | } else { | |
2143 | Some(( | |
2144 | match segment.res { | |
2145 | Res::PrimTy(ty) => format!("{} `{}`", segment.res.descr(), ty.name()), | |
923072b8 FG |
2146 | Res::Def(_, def_id) |
2147 | if let Some(name) = self.tcx().opt_item_name(def_id) => { | |
f2b60f7d | 2148 | format!("{} `{name}`", segment.res.descr()) |
923072b8 FG |
2149 | } |
2150 | Res::Err => "this type".to_string(), | |
f2b60f7d | 2151 | _ => segment.res.descr().to_string(), |
923072b8 FG |
2152 | }, |
2153 | segment.ident.span, | |
2154 | )) | |
f2b60f7d | 2155 | } |
923072b8 FG |
2156 | }) |
2157 | .collect(); | |
2158 | let this_type = match &types_and_spans[..] { | |
2159 | [.., _, (last, _)] => format!( | |
2160 | "{} and {last}", | |
2161 | types_and_spans[..types_and_spans.len() - 1] | |
2162 | .iter() | |
2163 | .map(|(x, _)| x.as_str()) | |
2164 | .intersperse(&", ") | |
2165 | .collect::<String>() | |
2166 | ), | |
2167 | [(only, _)] => only.to_string(), | |
2168 | [] => "this type".to_string(), | |
2169 | }; | |
2170 | ||
2171 | let arg_spans: Vec<Span> = args.map(|arg| arg.span()).collect(); | |
2172 | ||
2173 | let mut kinds = Vec::with_capacity(4); | |
2174 | if lt { | |
2175 | kinds.push("lifetime"); | |
2176 | } | |
2177 | if ty { | |
2178 | kinds.push("type"); | |
2179 | } | |
2180 | if ct { | |
2181 | kinds.push("const"); | |
dc9dc135 | 2182 | } |
923072b8 FG |
2183 | if inf { |
2184 | kinds.push("generic"); | |
2185 | } | |
2186 | let (kind, s) = match kinds[..] { | |
2187 | [.., _, last] => ( | |
2188 | format!( | |
2189 | "{} and {last}", | |
2190 | kinds[..kinds.len() - 1] | |
2191 | .iter() | |
2192 | .map(|&x| x) | |
2193 | .intersperse(", ") | |
2194 | .collect::<String>() | |
2195 | ), | |
2196 | "s", | |
2197 | ), | |
2198 | [only] => (format!("{only}"), ""), | |
2199 | [] => unreachable!(), | |
2200 | }; | |
2201 | let last_span = *arg_spans.last().unwrap(); | |
2202 | let span: MultiSpan = arg_spans.into(); | |
2203 | let mut err = struct_span_err!( | |
2204 | self.tcx().sess, | |
2205 | span, | |
2206 | E0109, | |
2207 | "{kind} arguments are not allowed on {this_type}", | |
2208 | ); | |
2209 | err.span_label(last_span, format!("{kind} argument{s} not allowed")); | |
2210 | for (what, span) in types_and_spans { | |
2211 | err.span_label(span, format!("not allowed on {what}")); | |
2212 | } | |
2213 | extend(&mut err); | |
2214 | err.emit(); | |
2215 | emitted = true; | |
2216 | } | |
74b04a01 | 2217 | |
923072b8 | 2218 | for segment in segments { |
74b04a01 | 2219 | // Only emit the first error to avoid overloading the user with error messages. |
5869c6ff | 2220 | if let [binding, ..] = segment.args().bindings { |
dc9dc135 | 2221 | Self::prohibit_assoc_ty_binding(self.tcx(), binding.span); |
923072b8 | 2222 | return true; |
dc9dc135 | 2223 | } |
8bb4bdeb | 2224 | } |
923072b8 | 2225 | emitted |
8bb4bdeb XL |
2226 | } |
2227 | ||
48663c56 XL |
2228 | // FIXME(eddyb, varkor) handle type paths here too, not just value ones. |
2229 | pub fn def_ids_for_value_path_segments( | |
2230 | &self, | |
dfeec247 | 2231 | segments: &[hir::PathSegment<'_>], |
48663c56 XL |
2232 | self_ty: Option<Ty<'tcx>>, |
2233 | kind: DefKind, | |
2234 | def_id: DefId, | |
2235 | ) -> Vec<PathSeg> { | |
0731742a XL |
2236 | // We need to extract the type parameters supplied by the user in |
2237 | // the path `path`. Due to the current setup, this is a bit of a | |
2238 | // tricky-process; the problem is that resolve only tells us the | |
2239 | // end-point of the path resolution, and not the intermediate steps. | |
2240 | // Luckily, we can (at least for now) deduce the intermediate steps | |
2241 | // just from the end-point. | |
2242 | // | |
2243 | // There are basically five cases to consider: | |
2244 | // | |
2245 | // 1. Reference to a constructor of a struct: | |
2246 | // | |
2247 | // struct Foo<T>(...) | |
2248 | // | |
2249 | // In this case, the parameters are declared in the type space. | |
2250 | // | |
2251 | // 2. Reference to a constructor of an enum variant: | |
2252 | // | |
2253 | // enum E<T> { Foo(...) } | |
2254 | // | |
2255 | // In this case, the parameters are defined in the type space, | |
2256 | // but may be specified either on the type or the variant. | |
2257 | // | |
2258 | // 3. Reference to a fn item or a free constant: | |
2259 | // | |
2260 | // fn foo<T>() { } | |
2261 | // | |
2262 | // In this case, the path will again always have the form | |
2263 | // `a::b::foo::<T>` where only the final segment should have | |
2264 | // type parameters. However, in this case, those parameters are | |
2265 | // declared on a value, and hence are in the `FnSpace`. | |
2266 | // | |
2267 | // 4. Reference to a method or an associated constant: | |
2268 | // | |
2269 | // impl<A> SomeStruct<A> { | |
2270 | // fn foo<B>(...) | |
2271 | // } | |
2272 | // | |
2273 | // Here we can have a path like | |
2274 | // `a::b::SomeStruct::<A>::foo::<B>`, in which case parameters | |
2275 | // may appear in two places. The penultimate segment, | |
2276 | // `SomeStruct::<A>`, contains parameters in TypeSpace, and the | |
2277 | // final segment, `foo::<B>` contains parameters in fn space. | |
2278 | // | |
0731742a XL |
2279 | // The first step then is to categorize the segments appropriately. |
2280 | ||
2281 | let tcx = self.tcx(); | |
2282 | ||
2283 | assert!(!segments.is_empty()); | |
2284 | let last = segments.len() - 1; | |
2285 | ||
2286 | let mut path_segs = vec![]; | |
2287 | ||
48663c56 | 2288 | match kind { |
0731742a | 2289 | // Case 1. Reference to a struct constructor. |
48663c56 | 2290 | DefKind::Ctor(CtorOf::Struct, ..) => { |
0731742a XL |
2291 | // Everything but the final segment should have no |
2292 | // parameters at all. | |
2293 | let generics = tcx.generics_of(def_id); | |
2294 | // Variant and struct constructors use the | |
2295 | // generics of their parent type definition. | |
2296 | let generics_def_id = generics.parent.unwrap_or(def_id); | |
2297 | path_segs.push(PathSeg(generics_def_id, last)); | |
2298 | } | |
2299 | ||
2300 | // Case 2. Reference to a variant constructor. | |
dfeec247 | 2301 | DefKind::Ctor(CtorOf::Variant, ..) | DefKind::Variant => { |
0731742a XL |
2302 | let adt_def = self_ty.map(|t| t.ty_adt_def().unwrap()); |
2303 | let (generics_def_id, index) = if let Some(adt_def) = adt_def { | |
2304 | debug_assert!(adt_def.is_enum()); | |
5e7ed085 | 2305 | (adt_def.did(), last) |
0731742a XL |
2306 | } else if last >= 1 && segments[last - 1].args.is_some() { |
2307 | // Everything but the penultimate segment should have no | |
2308 | // parameters at all. | |
532ac7d7 XL |
2309 | let mut def_id = def_id; |
2310 | ||
48663c56 XL |
2311 | // `DefKind::Ctor` -> `DefKind::Variant` |
2312 | if let DefKind::Ctor(..) = kind { | |
04454e1e | 2313 | def_id = tcx.parent(def_id); |
532ac7d7 XL |
2314 | } |
2315 | ||
48663c56 | 2316 | // `DefKind::Variant` -> `DefKind::Enum` |
04454e1e | 2317 | let enum_def_id = tcx.parent(def_id); |
0731742a XL |
2318 | (enum_def_id, last - 1) |
2319 | } else { | |
2320 | // FIXME: lint here recommending `Enum::<...>::Variant` form | |
2321 | // instead of `Enum::Variant::<...>` form. | |
2322 | ||
2323 | // Everything but the final segment should have no | |
2324 | // parameters at all. | |
2325 | let generics = tcx.generics_of(def_id); | |
2326 | // Variant and struct constructors use the | |
2327 | // generics of their parent type definition. | |
2328 | (generics.parent.unwrap_or(def_id), last) | |
2329 | }; | |
2330 | path_segs.push(PathSeg(generics_def_id, index)); | |
2331 | } | |
2332 | ||
2333 | // Case 3. Reference to a top-level value. | |
5e7ed085 | 2334 | DefKind::Fn | DefKind::Const | DefKind::ConstParam | DefKind::Static(_) => { |
0731742a XL |
2335 | path_segs.push(PathSeg(def_id, last)); |
2336 | } | |
2337 | ||
2338 | // Case 4. Reference to a method or associated const. | |
ba9703b0 | 2339 | DefKind::AssocFn | DefKind::AssocConst => { |
0731742a XL |
2340 | if segments.len() >= 2 { |
2341 | let generics = tcx.generics_of(def_id); | |
2342 | path_segs.push(PathSeg(generics.parent.unwrap(), last - 1)); | |
2343 | } | |
2344 | path_segs.push(PathSeg(def_id, last)); | |
2345 | } | |
2346 | ||
48663c56 | 2347 | kind => bug!("unexpected definition kind {:?} for {:?}", kind, def_id), |
0731742a XL |
2348 | } |
2349 | ||
2350 | debug!("path_segs = {:?}", path_segs); | |
2351 | ||
2352 | path_segs | |
2353 | } | |
2354 | ||
a1dfa0c6 | 2355 | // Check a type `Path` and convert it to a `Ty`. |
dfeec247 XL |
2356 | pub fn res_to_ty( |
2357 | &self, | |
2358 | opt_self_ty: Option<Ty<'tcx>>, | |
2359 | path: &hir::Path<'_>, | |
2360 | permit_variants: bool, | |
2361 | ) -> Ty<'tcx> { | |
a7813a04 XL |
2362 | let tcx = self.tcx(); |
2363 | ||
dfeec247 XL |
2364 | debug!( |
2365 | "res_to_ty(res={:?}, opt_self_ty={:?}, path_segments={:?})", | |
2366 | path.res, opt_self_ty, path.segments | |
2367 | ); | |
a7813a04 | 2368 | |
476ff2be | 2369 | let span = path.span; |
48663c56 | 2370 | match path.res { |
f2b60f7d | 2371 | Res::Def(DefKind::OpaqueTy | DefKind::ImplTraitPlaceholder, did) => { |
dc9dc135 | 2372 | // Check for desugared `impl Trait`. |
0bf4aa26 | 2373 | assert!(ty::is_impl_trait_defn(tcx, did).is_none()); |
8faf50e0 | 2374 | let item_segment = path.segments.split_last().unwrap(); |
923072b8 FG |
2375 | self.prohibit_generics(item_segment.1.iter(), |err| { |
2376 | err.note("`impl Trait` types can't have type parameters"); | |
2377 | }); | |
8faf50e0 | 2378 | let substs = self.ast_path_substs_for_ty(span, did, item_segment.0); |
dfeec247 | 2379 | self.normalize_ty(span, tcx.mk_opaque(did, substs)) |
8faf50e0 | 2380 | } |
ba9703b0 XL |
2381 | Res::Def( |
2382 | DefKind::Enum | |
2383 | | DefKind::TyAlias | |
2384 | | DefKind::Struct | |
2385 | | DefKind::Union | |
2386 | | DefKind::ForeignTy, | |
2387 | did, | |
2388 | ) => { | |
476ff2be | 2389 | assert_eq!(opt_self_ty, None); |
923072b8 | 2390 | self.prohibit_generics(path.segments.split_last().unwrap().1.iter(), |_| {}); |
32a655c1 | 2391 | self.ast_path_to_ty(span, did, path.segments.last().unwrap()) |
a7813a04 | 2392 | } |
48663c56 | 2393 | Res::Def(kind @ DefKind::Variant, def_id) if permit_variants => { |
c30ab7b3 SL |
2394 | // Convert "variant type" as if it were a real type. |
2395 | // The resulting `Ty` is type of the variant's enum for now. | |
476ff2be | 2396 | assert_eq!(opt_self_ty, None); |
0731742a | 2397 | |
48663c56 | 2398 | let path_segs = |
c295e0f8 | 2399 | self.def_ids_for_value_path_segments(path.segments, None, kind, def_id); |
0731742a XL |
2400 | let generic_segs: FxHashSet<_> = |
2401 | path_segs.iter().map(|PathSeg(_, index)| index).collect(); | |
923072b8 FG |
2402 | self.prohibit_generics( |
2403 | path.segments.iter().enumerate().filter_map(|(index, seg)| { | |
dfeec247 | 2404 | if !generic_segs.contains(&index) { Some(seg) } else { None } |
923072b8 FG |
2405 | }), |
2406 | |err| { | |
2407 | err.note("enum variants can't have type parameters"); | |
dfeec247 | 2408 | }, |
923072b8 | 2409 | ); |
0731742a XL |
2410 | |
2411 | let PathSeg(def_id, index) = path_segs.last().unwrap(); | |
2412 | self.ast_path_to_ty(span, *def_id, &path.segments[*index]) | |
c30ab7b3 | 2413 | } |
dc9dc135 | 2414 | Res::Def(DefKind::TyParam, def_id) => { |
476ff2be | 2415 | assert_eq!(opt_self_ty, None); |
923072b8 FG |
2416 | self.prohibit_generics(path.segments.iter(), |err| { |
2417 | if let Some(span) = tcx.def_ident_span(def_id) { | |
2418 | let name = tcx.item_name(def_id); | |
2419 | err.span_note(span, &format!("type parameter `{name}` defined here")); | |
2420 | } | |
2421 | }); | |
9e0c209e | 2422 | |
04454e1e FG |
2423 | let def_id = def_id.expect_local(); |
2424 | let item_def_id = tcx.hir().ty_param_owner(def_id); | |
7cac9316 | 2425 | let generics = tcx.generics_of(item_def_id); |
04454e1e FG |
2426 | let index = generics.param_def_id_to_index[&def_id.to_def_id()]; |
2427 | tcx.mk_ty_param(index, tcx.hir().ty_param_name(def_id)) | |
a7813a04 | 2428 | } |
5099ac24 | 2429 | Res::SelfTy { trait_: Some(_), alias_to: None } => { |
dc9dc135 | 2430 | // `Self` in trait or type alias. |
476ff2be | 2431 | assert_eq!(opt_self_ty, None); |
923072b8 FG |
2432 | self.prohibit_generics(path.segments.iter(), |err| { |
2433 | if let [hir::PathSegment { args: Some(args), ident, .. }] = &path.segments[..] { | |
2434 | err.span_suggestion_verbose( | |
2435 | ident.span.shrink_to_hi().to(args.span_ext), | |
2436 | "the `Self` type doesn't accept type parameters", | |
2437 | "", | |
2438 | Applicability::MaybeIncorrect, | |
2439 | ); | |
2440 | } | |
2441 | }); | |
e1599b0c | 2442 | tcx.types.self_param |
9346a6ac | 2443 | } |
5099ac24 | 2444 | Res::SelfTy { trait_: _, alias_to: Some((def_id, forbid_generic)) } => { |
dc9dc135 | 2445 | // `Self` in impl (we know the concrete type). |
476ff2be | 2446 | assert_eq!(opt_self_ty, None); |
dc9dc135 | 2447 | // Try to evaluate any array length constants. |
5099ac24 | 2448 | let ty = tcx.at(span).type_of(def_id); |
923072b8 FG |
2449 | let span_of_impl = tcx.span_of_impl(def_id); |
2450 | self.prohibit_generics(path.segments.iter(), |err| { | |
2451 | let def_id = match *ty.kind() { | |
2452 | ty::Adt(self_def, _) => self_def.did(), | |
2453 | _ => return, | |
2454 | }; | |
2455 | ||
2456 | let type_name = tcx.item_name(def_id); | |
2457 | let span_of_ty = tcx.def_ident_span(def_id); | |
2458 | let generics = tcx.generics_of(def_id).count(); | |
2459 | ||
2460 | let msg = format!("`Self` is of type `{ty}`"); | |
2461 | if let (Ok(i_sp), Some(t_sp)) = (span_of_impl, span_of_ty) { | |
923072b8 FG |
2462 | let mut span: MultiSpan = vec![t_sp].into(); |
2463 | span.push_span_label( | |
2464 | i_sp, | |
2465 | &format!("`Self` is on type `{type_name}` in this `impl`"), | |
2466 | ); | |
2467 | let mut postfix = ""; | |
2468 | if generics == 0 { | |
2469 | postfix = ", which doesn't have generic parameters"; | |
2470 | } | |
2471 | span.push_span_label( | |
2472 | t_sp, | |
2473 | &format!("`Self` corresponds to this type{postfix}"), | |
2474 | ); | |
2475 | err.span_note(span, &msg); | |
2476 | } else { | |
2477 | err.note(&msg); | |
2478 | } | |
2479 | for segment in path.segments { | |
2480 | if let Some(args) = segment.args && segment.ident.name == kw::SelfUpper { | |
2481 | if generics == 0 { | |
2482 | // FIXME(estebank): we could also verify that the arguments being | |
2483 | // work for the `enum`, instead of just looking if it takes *any*. | |
2484 | err.span_suggestion_verbose( | |
2485 | segment.ident.span.shrink_to_hi().to(args.span_ext), | |
2486 | "the `Self` type doesn't accept type parameters", | |
2487 | "", | |
2488 | Applicability::MachineApplicable, | |
2489 | ); | |
2490 | return; | |
2491 | } else { | |
2492 | err.span_suggestion_verbose( | |
2493 | segment.ident.span, | |
2494 | format!( | |
2495 | "the `Self` type doesn't accept type parameters, use the \ | |
2496 | concrete type's name `{type_name}` instead if you want to \ | |
2497 | specify its type parameters" | |
2498 | ), | |
064997fb | 2499 | type_name, |
923072b8 FG |
2500 | Applicability::MaybeIncorrect, |
2501 | ); | |
2502 | } | |
2503 | } | |
2504 | } | |
2505 | }); | |
5099ac24 FG |
2506 | // HACK(min_const_generics): Forbid generic `Self` types |
2507 | // here as we can't easily do that during nameres. | |
2508 | // | |
2509 | // We do this before normalization as we otherwise allow | |
2510 | // ```rust | |
2511 | // trait AlwaysApplicable { type Assoc; } | |
2512 | // impl<T: ?Sized> AlwaysApplicable for T { type Assoc = usize; } | |
2513 | // | |
2514 | // trait BindsParam<T> { | |
2515 | // type ArrayTy; | |
2516 | // } | |
2517 | // impl<T> BindsParam<T> for <T as AlwaysApplicable>::Assoc { | |
2518 | // type ArrayTy = [u8; Self::MAX]; | |
2519 | // } | |
2520 | // ``` | |
2521 | // Note that the normalization happens in the param env of | |
2522 | // the anon const, which is empty. This is why the | |
2523 | // `AlwaysApplicable` impl needs a `T: ?Sized` bound for | |
2524 | // this to compile if we were to normalize here. | |
2525 | if forbid_generic && ty.needs_subst() { | |
1b1a35ee XL |
2526 | let mut err = tcx.sess.struct_span_err( |
2527 | path.span, | |
2528 | "generic `Self` types are currently not permitted in anonymous constants", | |
2529 | ); | |
2530 | if let Some(hir::Node::Item(&hir::Item { | |
5869c6ff | 2531 | kind: hir::ItemKind::Impl(ref impl_), |
1b1a35ee XL |
2532 | .. |
2533 | })) = tcx.hir().get_if_local(def_id) | |
2534 | { | |
5869c6ff | 2535 | err.span_note(impl_.self_ty.span, "not a concrete type"); |
1b1a35ee XL |
2536 | } |
2537 | err.emit(); | |
2538 | tcx.ty_error() | |
2539 | } else { | |
5099ac24 | 2540 | self.normalize_ty(span, ty) |
1b1a35ee | 2541 | } |
a7813a04 | 2542 | } |
dc9dc135 | 2543 | Res::Def(DefKind::AssocTy, def_id) => { |
0731742a | 2544 | debug_assert!(path.segments.len() >= 2); |
923072b8 | 2545 | self.prohibit_generics(path.segments[..path.segments.len() - 2].iter(), |_| {}); |
dfeec247 XL |
2546 | self.qpath_to_ty( |
2547 | span, | |
2548 | opt_self_ty, | |
2549 | def_id, | |
2550 | &path.segments[path.segments.len() - 2], | |
2551 | path.segments.last().unwrap(), | |
2552 | ) | |
a7813a04 | 2553 | } |
48663c56 | 2554 | Res::PrimTy(prim_ty) => { |
476ff2be | 2555 | assert_eq!(opt_self_ty, None); |
923072b8 FG |
2556 | self.prohibit_generics(path.segments.iter(), |err| { |
2557 | let name = prim_ty.name_str(); | |
2558 | for segment in path.segments { | |
2559 | if let Some(args) = segment.args { | |
2560 | err.span_suggestion_verbose( | |
2561 | segment.ident.span.shrink_to_hi().to(args.span_ext), | |
2562 | &format!("primitive type `{name}` doesn't have generic parameters"), | |
2563 | "", | |
2564 | Applicability::MaybeIncorrect, | |
2565 | ); | |
2566 | } | |
2567 | } | |
2568 | }); | |
8bb4bdeb | 2569 | match prim_ty { |
dfeec247 XL |
2570 | hir::PrimTy::Bool => tcx.types.bool, |
2571 | hir::PrimTy::Char => tcx.types.char, | |
5869c6ff XL |
2572 | hir::PrimTy::Int(it) => tcx.mk_mach_int(ty::int_ty(it)), |
2573 | hir::PrimTy::Uint(uit) => tcx.mk_mach_uint(ty::uint_ty(uit)), | |
2574 | hir::PrimTy::Float(ft) => tcx.mk_mach_float(ty::float_ty(ft)), | |
f035d41b | 2575 | hir::PrimTy::Str => tcx.types.str_, |
8bb4bdeb | 2576 | } |
a7813a04 | 2577 | } |
48663c56 | 2578 | Res::Err => { |
a7813a04 | 2579 | self.set_tainted_by_errors(); |
f035d41b | 2580 | self.tcx().ty_error() |
a7813a04 | 2581 | } |
dfeec247 | 2582 | _ => span_bug!(span, "unexpected resolution: {:?}", path.res), |
c34b1796 | 2583 | } |
9346a6ac | 2584 | } |
c34b1796 | 2585 | |
a7813a04 XL |
2586 | /// Parses the programmer's textual representation of a type into our |
2587 | /// internal notion of a type. | |
dfeec247 | 2588 | pub fn ast_ty_to_ty(&self, ast_ty: &hir::Ty<'_>) -> Ty<'tcx> { |
a2a8927a XL |
2589 | self.ast_ty_to_ty_inner(ast_ty, false, false) |
2590 | } | |
2591 | ||
2592 | /// Parses the programmer's textual representation of a type into our | |
2593 | /// internal notion of a type. This is meant to be used within a path. | |
2594 | pub fn ast_ty_to_ty_in_path(&self, ast_ty: &hir::Ty<'_>) -> Ty<'tcx> { | |
2595 | self.ast_ty_to_ty_inner(ast_ty, false, true) | |
3dfed10e XL |
2596 | } |
2597 | ||
2598 | /// Turns a `hir::Ty` into a `Ty`. For diagnostics' purposes we keep track of whether trait | |
2599 | /// objects are borrowed like `&dyn Trait` to avoid emitting redundant errors. | |
f2b60f7d | 2600 | #[instrument(level = "debug", skip(self), ret)] |
a2a8927a | 2601 | fn ast_ty_to_ty_inner(&self, ast_ty: &hir::Ty<'_>, borrowed: bool, in_path: bool) -> Ty<'tcx> { |
a7813a04 | 2602 | let tcx = self.tcx(); |
1a4d82fc | 2603 | |
e74abb32 | 2604 | let result_ty = match ast_ty.kind { |
c295e0f8 | 2605 | hir::TyKind::Slice(ref ty) => tcx.mk_slice(self.ast_ty_to_ty(ty)), |
8faf50e0 | 2606 | hir::TyKind::Ptr(ref mt) => { |
c295e0f8 | 2607 | tcx.mk_ptr(ty::TypeAndMut { ty: self.ast_ty_to_ty(mt.ty), mutbl: mt.mutbl }) |
a7813a04 | 2608 | } |
8faf50e0 | 2609 | hir::TyKind::Rptr(ref region, ref mt) => { |
32a655c1 | 2610 | let r = self.ast_region_to_region(region, None); |
cdc7bbd5 | 2611 | debug!(?r); |
a2a8927a | 2612 | let t = self.ast_ty_to_ty_inner(mt.ty, true, false); |
dfeec247 | 2613 | tcx.mk_ref(r, ty::TypeAndMut { ty: t, mutbl: mt.mutbl }) |
a7813a04 | 2614 | } |
dfeec247 | 2615 | hir::TyKind::Never => tcx.types.never, |
c295e0f8 XL |
2616 | hir::TyKind::Tup(fields) => tcx.mk_tup(fields.iter().map(|t| self.ast_ty_to_ty(t))), |
2617 | hir::TyKind::BareFn(bf) => { | |
2618 | require_c_abi_if_c_variadic(tcx, bf.decl, bf.abi, ast_ty.span); | |
6a06907d | 2619 | |
74b04a01 | 2620 | tcx.mk_fn_ptr(self.ty_of_fn( |
cdc7bbd5 | 2621 | ast_ty.hir_id, |
74b04a01 XL |
2622 | bf.unsafety, |
2623 | bf.abi, | |
c295e0f8 | 2624 | bf.decl, |
74b04a01 | 2625 | None, |
6a06907d | 2626 | Some(ast_ty), |
74b04a01 | 2627 | )) |
1a4d82fc | 2628 | } |
f2b60f7d | 2629 | hir::TyKind::TraitObject(bounds, ref lifetime, repr) => { |
a2a8927a | 2630 | self.maybe_lint_bare_trait(ast_ty, in_path); |
f2b60f7d FG |
2631 | let repr = match repr { |
2632 | TraitObjectSyntax::Dyn | TraitObjectSyntax::None => ty::Dyn, | |
2633 | TraitObjectSyntax::DynStar => ty::DynStar, | |
2634 | }; | |
2635 | self.conv_object_ty_poly_trait_ref(ast_ty.span, bounds, lifetime, borrowed, repr) | |
a7813a04 | 2636 | } |
8faf50e0 | 2637 | hir::TyKind::Path(hir::QPath::Resolved(ref maybe_qself, ref path)) => { |
cdc7bbd5 | 2638 | debug!(?maybe_qself, ?path); |
dfeec247 | 2639 | let opt_self_ty = maybe_qself.as_ref().map(|qself| self.ast_ty_to_ty(qself)); |
48663c56 | 2640 | self.res_to_ty(opt_self_ty, path, false) |
476ff2be | 2641 | } |
f2b60f7d | 2642 | hir::TyKind::OpaqueDef(item_id, lifetimes, in_trait) => { |
6a06907d XL |
2643 | let opaque_ty = tcx.hir().item(item_id); |
2644 | let def_id = item_id.def_id.to_def_id(); | |
f035d41b XL |
2645 | |
2646 | match opaque_ty.kind { | |
923072b8 | 2647 | hir::ItemKind::OpaqueTy(hir::OpaqueTy { origin, .. }) => { |
f2b60f7d | 2648 | self.impl_trait_ty_to_ty(def_id, lifetimes, origin, in_trait) |
923072b8 | 2649 | } |
f035d41b XL |
2650 | ref i => bug!("`impl Trait` pointed to non-opaque type?? {:#?}", i), |
2651 | } | |
dc9dc135 | 2652 | } |
8faf50e0 | 2653 | hir::TyKind::Path(hir::QPath::TypeRelative(ref qself, ref segment)) => { |
cdc7bbd5 | 2654 | debug!(?qself, ?segment); |
a2a8927a | 2655 | let ty = self.ast_ty_to_ty_inner(qself, false, true); |
923072b8 | 2656 | self.associated_path_to_ty(ast_ty.hir_id, ast_ty.span, ty, qself, segment, false) |
dfeec247 | 2657 | .map(|(ty, _, _)| ty) |
f035d41b | 2658 | .unwrap_or_else(|_| tcx.ty_error()) |
a7813a04 | 2659 | } |
a2a8927a | 2660 | hir::TyKind::Path(hir::QPath::LangItem(lang_item, span, _)) => { |
3dfed10e | 2661 | let def_id = tcx.require_lang_item(lang_item, Some(span)); |
cdc7bbd5 | 2662 | let (substs, _) = self.create_substs_for_ast_path( |
3dfed10e XL |
2663 | span, |
2664 | def_id, | |
2665 | &[], | |
5869c6ff | 2666 | &hir::PathSegment::invalid(), |
3dfed10e XL |
2667 | &GenericArgs::none(), |
2668 | true, | |
2669 | None, | |
2670 | ); | |
04454e1e FG |
2671 | EarlyBinder(self.normalize_ty(span, tcx.at(span).type_of(def_id))) |
2672 | .subst(tcx, substs) | |
3dfed10e | 2673 | } |
8faf50e0 | 2674 | hir::TyKind::Array(ref ty, ref length) => { |
a2a8927a XL |
2675 | let length = match length { |
2676 | &hir::ArrayLen::Infer(_, span) => self.ct_infer(tcx.types.usize, None, span), | |
2677 | hir::ArrayLen::Body(constant) => { | |
2678 | let length_def_id = tcx.hir().local_def_id(constant.hir_id); | |
2679 | ty::Const::from_anon_const(tcx, length_def_id) | |
2680 | } | |
2681 | }; | |
2682 | ||
c295e0f8 | 2683 | let array_ty = tcx.mk_ty(ty::Array(self.ast_ty_to_ty(ty), length)); |
ea8adc8c | 2684 | self.normalize_ty(ast_ty.span, array_ty) |
1a4d82fc | 2685 | } |
cdc7bbd5 | 2686 | hir::TyKind::Typeof(ref e) => { |
f2b60f7d FG |
2687 | let ty_erased = tcx.type_of(tcx.hir().local_def_id(e.hir_id)); |
2688 | let ty = tcx.fold_regions(ty_erased, |r, _| { | |
2689 | if r.is_erased() { tcx.lifetimes.re_static } else { r } | |
2690 | }); | |
04454e1e FG |
2691 | let span = ast_ty.span; |
2692 | tcx.sess.emit_err(TypeofReservedKeywordUsed { | |
2693 | span, | |
2694 | ty, | |
2695 | opt_sugg: Some((span, Applicability::MachineApplicable)) | |
064997fb | 2696 | .filter(|_| ty.is_suggestable(tcx, false)), |
04454e1e FG |
2697 | }); |
2698 | ||
2699 | ty | |
a7813a04 | 2700 | } |
8faf50e0 | 2701 | hir::TyKind::Infer => { |
b7449926 | 2702 | // Infer also appears as the type of arguments or return |
94222f64 | 2703 | // values in an ExprKind::Closure, or as |
a7813a04 XL |
2704 | // the type of local variables. Both of these cases are |
2705 | // handled specially and will not descend into this routine. | |
dc9dc135 | 2706 | self.ty_infer(None, ast_ty.span) |
cc61c64b | 2707 | } |
f035d41b | 2708 | hir::TyKind::Err => tcx.ty_error(), |
a7813a04 | 2709 | }; |
1a4d82fc | 2710 | |
ea8adc8c | 2711 | self.record_ty(ast_ty.hir_id, result_ty, ast_ty.span); |
a7813a04 | 2712 | result_ty |
1a4d82fc | 2713 | } |
1a4d82fc | 2714 | |
f2b60f7d | 2715 | #[instrument(level = "debug", skip(self), ret)] |
cdc7bbd5 | 2716 | fn impl_trait_ty_to_ty( |
94b46f34 XL |
2717 | &self, |
2718 | def_id: DefId, | |
dfeec247 | 2719 | lifetimes: &[hir::GenericArg<'_>], |
923072b8 | 2720 | origin: OpaqueTyOrigin, |
f2b60f7d | 2721 | in_trait: bool, |
94b46f34 | 2722 | ) -> Ty<'tcx> { |
ff7c6d11 XL |
2723 | debug!("impl_trait_ty_to_ty(def_id={:?}, lifetimes={:?})", def_id, lifetimes); |
2724 | let tcx = self.tcx(); | |
94b46f34 | 2725 | |
ff7c6d11 XL |
2726 | let generics = tcx.generics_of(def_id); |
2727 | ||
ff7c6d11 | 2728 | debug!("impl_trait_ty_to_ty: generics={:?}", generics); |
532ac7d7 | 2729 | let substs = InternalSubsts::for_item(tcx, def_id, |param, _| { |
94b46f34 XL |
2730 | if let Some(i) = (param.index as usize).checked_sub(generics.parent_count) { |
2731 | // Our own parameters are the resolved lifetimes. | |
c295e0f8 XL |
2732 | if let GenericParamDefKind::Lifetime = param.kind { |
2733 | if let hir::GenericArg::Lifetime(lifetime) = &lifetimes[i] { | |
94222f64 | 2734 | self.ast_region_to_region(lifetime, None).into() |
c295e0f8 XL |
2735 | } else { |
2736 | bug!() | |
94b46f34 | 2737 | } |
c295e0f8 XL |
2738 | } else { |
2739 | bug!() | |
94b46f34 XL |
2740 | } |
2741 | } else { | |
94b46f34 | 2742 | match param.kind { |
f035d41b XL |
2743 | // For RPIT (return position impl trait), only lifetimes |
2744 | // mentioned in the impl Trait predicate are captured by | |
2745 | // the opaque type, so the lifetime parameters from the | |
2746 | // parent item need to be replaced with `'static`. | |
2747 | // | |
2748 | // For `impl Trait` in the types of statics, constants, | |
2749 | // locals and type aliases. These capture all parent | |
2750 | // lifetimes, so they can use their identity subst. | |
923072b8 FG |
2751 | GenericParamDefKind::Lifetime |
2752 | if matches!( | |
2753 | origin, | |
2754 | hir::OpaqueTyOrigin::FnReturn(..) | hir::OpaqueTyOrigin::AsyncFn(..) | |
2755 | ) => | |
2756 | { | |
f035d41b XL |
2757 | tcx.lifetimes.re_static.into() |
2758 | } | |
dfeec247 | 2759 | _ => tcx.mk_param_from_def(param), |
ff7c6d11 XL |
2760 | } |
2761 | } | |
94b46f34 | 2762 | }); |
dc9dc135 | 2763 | debug!("impl_trait_ty_to_ty: substs={:?}", substs); |
ff7c6d11 | 2764 | |
f2b60f7d | 2765 | if in_trait { tcx.mk_projection(def_id, substs) } else { tcx.mk_opaque(def_id, substs) } |
ff7c6d11 XL |
2766 | } |
2767 | ||
dfeec247 | 2768 | pub fn ty_of_arg(&self, ty: &hir::Ty<'_>, expected_ty: Option<Ty<'tcx>>) -> Ty<'tcx> { |
e74abb32 | 2769 | match ty.kind { |
8faf50e0 | 2770 | hir::TyKind::Infer if expected_ty.is_some() => { |
ea8adc8c XL |
2771 | self.record_ty(ty.hir_id, expected_ty.unwrap(), ty.span); |
2772 | expected_ty.unwrap() | |
2773 | } | |
32a655c1 | 2774 | _ => self.ast_ty_to_ty(ty), |
a7813a04 XL |
2775 | } |
2776 | } | |
1a4d82fc | 2777 | |
dfeec247 XL |
2778 | pub fn ty_of_fn( |
2779 | &self, | |
cdc7bbd5 | 2780 | hir_id: hir::HirId, |
dfeec247 XL |
2781 | unsafety: hir::Unsafety, |
2782 | abi: abi::Abi, | |
2783 | decl: &hir::FnDecl<'_>, | |
04454e1e | 2784 | generics: Option<&hir::Generics<'_>>, |
6a06907d | 2785 | hir_ty: Option<&hir::Ty<'_>>, |
dfeec247 | 2786 | ) -> ty::PolyFnSig<'tcx> { |
32a655c1 | 2787 | debug!("ty_of_fn"); |
1a4d82fc | 2788 | |
ea8adc8c | 2789 | let tcx = self.tcx(); |
cdc7bbd5 XL |
2790 | let bound_vars = tcx.late_bound_vars(hir_id); |
2791 | debug!(?bound_vars); | |
1a4d82fc | 2792 | |
74b04a01 | 2793 | // We proactively collect all the inferred type params to emit a single error per fn def. |
5099ac24 | 2794 | let mut visitor = HirPlaceholderCollector::default(); |
04454e1e FG |
2795 | let mut infer_replacements = vec![]; |
2796 | ||
2797 | if let Some(generics) = generics { | |
2798 | walk_generics(&mut visitor, generics); | |
dfeec247 | 2799 | } |
74b04a01 | 2800 | |
04454e1e FG |
2801 | let input_tys: Vec<_> = decl |
2802 | .inputs | |
2803 | .iter() | |
2804 | .enumerate() | |
2805 | .map(|(i, a)| { | |
2806 | if let hir::TyKind::Infer = a.kind && !self.allow_ty_infer() { | |
2807 | if let Some(suggested_ty) = | |
2808 | self.suggest_trait_fn_ty_for_impl_fn_infer(hir_id, Some(i)) | |
2809 | { | |
2810 | infer_replacements.push((a.span, suggested_ty.to_string())); | |
2811 | return suggested_ty; | |
2812 | } | |
2813 | } | |
2814 | ||
2815 | // Only visit the type looking for `_` if we didn't fix the type above | |
2816 | visitor.visit_ty(a); | |
2817 | self.ty_of_arg(a, None) | |
2818 | }) | |
2819 | .collect(); | |
2820 | ||
a7813a04 | 2821 | let output_ty = match decl.output { |
c295e0f8 | 2822 | hir::FnRetTy::Return(output) => { |
04454e1e FG |
2823 | if let hir::TyKind::Infer = output.kind |
2824 | && !self.allow_ty_infer() | |
2825 | && let Some(suggested_ty) = | |
2826 | self.suggest_trait_fn_ty_for_impl_fn_infer(hir_id, None) | |
2827 | { | |
2828 | infer_replacements.push((output.span, suggested_ty.to_string())); | |
2829 | suggested_ty | |
2830 | } else { | |
2831 | visitor.visit_ty(output); | |
2832 | self.ast_ty_to_ty(output) | |
2833 | } | |
dfeec247 | 2834 | } |
74b04a01 | 2835 | hir::FnRetTy::DefaultReturn(..) => tcx.mk_unit(), |
a7813a04 | 2836 | }; |
1a4d82fc | 2837 | |
32a655c1 | 2838 | debug!("ty_of_fn: output_ty={:?}", output_ty); |
9e0c209e | 2839 | |
04454e1e | 2840 | let fn_ty = tcx.mk_fn_sig(input_tys.into_iter(), output_ty, decl.c_variadic, unsafety, abi); |
cdc7bbd5 | 2841 | let bare_fn_ty = ty::Binder::bind_with_vars(fn_ty, bound_vars); |
dfeec247 | 2842 | |
04454e1e | 2843 | if !self.allow_ty_infer() && !(visitor.0.is_empty() && infer_replacements.is_empty()) { |
dfeec247 XL |
2844 | // We always collect the spans for placeholder types when evaluating `fn`s, but we |
2845 | // only want to emit an error complaining about them if infer types (`_`) are not | |
ba9703b0 XL |
2846 | // allowed. `allow_ty_infer` gates this behavior. We check for the presence of |
2847 | // `ident_span` to not emit an error twice when we have `fn foo(_: fn() -> _)`. | |
6a06907d | 2848 | |
04454e1e | 2849 | let mut diag = crate::collect::placeholder_type_error_diag( |
dfeec247 | 2850 | tcx, |
04454e1e | 2851 | generics, |
dfeec247 | 2852 | visitor.0, |
04454e1e | 2853 | infer_replacements.iter().map(|(s, _)| *s).collect(), |
ba9703b0 | 2854 | true, |
6a06907d | 2855 | hir_ty, |
136023e0 | 2856 | "function", |
dfeec247 | 2857 | ); |
04454e1e FG |
2858 | |
2859 | if !infer_replacements.is_empty() { | |
f2b60f7d FG |
2860 | diag.multipart_suggestion( |
2861 | &format!( | |
04454e1e FG |
2862 | "try replacing `_` with the type{} in the corresponding trait method signature", |
2863 | rustc_errors::pluralize!(infer_replacements.len()), | |
f2b60f7d FG |
2864 | ), |
2865 | infer_replacements, | |
2866 | Applicability::MachineApplicable, | |
2867 | ); | |
04454e1e FG |
2868 | } |
2869 | ||
2870 | diag.emit(); | |
dfeec247 | 2871 | } |
ea8adc8c XL |
2872 | |
2873 | // Find any late-bound regions declared in return type that do | |
0bf4aa26 | 2874 | // not appear in the arguments. These are not well-formed. |
ea8adc8c XL |
2875 | // |
2876 | // Example: | |
2877 | // for<'a> fn() -> &'a str <-- 'a is bad | |
2878 | // for<'a> fn(&'a String) -> &'a str <-- 'a is ok | |
2879 | let inputs = bare_fn_ty.inputs(); | |
dfeec247 XL |
2880 | let late_bound_in_args = |
2881 | tcx.collect_constrained_late_bound_regions(&inputs.map_bound(|i| i.to_owned())); | |
ea8adc8c XL |
2882 | let output = bare_fn_ty.output(); |
2883 | let late_bound_in_ret = tcx.collect_referenced_late_bound_regions(&output); | |
3dfed10e XL |
2884 | |
2885 | self.validate_late_bound_regions(late_bound_in_args, late_bound_in_ret, |br_name| { | |
2886 | struct_span_err!( | |
dfeec247 XL |
2887 | tcx.sess, |
2888 | decl.output.span(), | |
2889 | E0581, | |
3dfed10e XL |
2890 | "return type references {}, which is not constrained by the fn input types", |
2891 | br_name | |
2892 | ) | |
2893 | }); | |
2894 | ||
2895 | bare_fn_ty | |
2896 | } | |
2897 | ||
04454e1e FG |
2898 | /// Given a fn_hir_id for a impl function, suggest the type that is found on the |
2899 | /// corresponding function in the trait that the impl implements, if it exists. | |
2900 | /// If arg_idx is Some, then it corresponds to an input type index, otherwise it | |
2901 | /// corresponds to the return type. | |
2902 | fn suggest_trait_fn_ty_for_impl_fn_infer( | |
2903 | &self, | |
2904 | fn_hir_id: hir::HirId, | |
2905 | arg_idx: Option<usize>, | |
2906 | ) -> Option<Ty<'tcx>> { | |
2907 | let tcx = self.tcx(); | |
2908 | let hir = tcx.hir(); | |
2909 | ||
2910 | let hir::Node::ImplItem(hir::ImplItem { kind: hir::ImplItemKind::Fn(..), ident, .. }) = | |
2911 | hir.get(fn_hir_id) else { return None }; | |
2912 | let hir::Node::Item(hir::Item { kind: hir::ItemKind::Impl(i), .. }) = | |
2913 | hir.get(hir.get_parent_node(fn_hir_id)) else { bug!("ImplItem should have Impl parent") }; | |
2914 | ||
2915 | let trait_ref = | |
2916 | self.instantiate_mono_trait_ref(i.of_trait.as_ref()?, self.ast_ty_to_ty(i.self_ty)); | |
2917 | ||
2918 | let assoc = tcx.associated_items(trait_ref.def_id).find_by_name_and_kind( | |
2919 | tcx, | |
2920 | *ident, | |
2921 | ty::AssocKind::Fn, | |
2922 | trait_ref.def_id, | |
2923 | )?; | |
2924 | ||
2925 | let fn_sig = tcx.bound_fn_sig(assoc.def_id).subst( | |
2926 | tcx, | |
2927 | trait_ref.substs.extend_to(tcx, assoc.def_id, |param, _| tcx.mk_param_from_def(param)), | |
2928 | ); | |
2929 | ||
2930 | let ty = if let Some(arg_idx) = arg_idx { fn_sig.input(arg_idx) } else { fn_sig.output() }; | |
2931 | ||
2932 | Some(tcx.liberate_late_bound_regions(fn_hir_id.expect_owner().to_def_id(), ty)) | |
2933 | } | |
2934 | ||
3dfed10e XL |
2935 | fn validate_late_bound_regions( |
2936 | &self, | |
fc512014 XL |
2937 | constrained_regions: FxHashSet<ty::BoundRegionKind>, |
2938 | referenced_regions: FxHashSet<ty::BoundRegionKind>, | |
5e7ed085 | 2939 | generate_err: impl Fn(&str) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>, |
3dfed10e XL |
2940 | ) { |
2941 | for br in referenced_regions.difference(&constrained_regions) { | |
2942 | let br_name = match *br { | |
923072b8 FG |
2943 | ty::BrNamed(_, kw::UnderscoreLifetime) | ty::BrAnon(_) | ty::BrEnv => { |
2944 | "an anonymous lifetime".to_string() | |
2945 | } | |
3dfed10e | 2946 | ty::BrNamed(_, name) => format!("lifetime `{}`", name), |
3dfed10e XL |
2947 | }; |
2948 | ||
2949 | let mut err = generate_err(&br_name); | |
2950 | ||
923072b8 | 2951 | if let ty::BrNamed(_, kw::UnderscoreLifetime) | ty::BrAnon(_) = *br { |
2c00a5a8 XL |
2952 | // The only way for an anonymous lifetime to wind up |
2953 | // in the return type but **also** be unconstrained is | |
2954 | // if it only appears in "associated types" in the | |
3dfed10e | 2955 | // input. See #47511 and #62200 for examples. In this case, |
2c00a5a8 XL |
2956 | // though we can easily give a hint that ought to be |
2957 | // relevant. | |
dfeec247 | 2958 | err.note( |
f2b60f7d | 2959 | "lifetimes appearing in an associated or opaque type are not considered constrained", |
dfeec247 | 2960 | ); |
f2b60f7d | 2961 | err.note("consider introducing a named lifetime parameter"); |
2c00a5a8 | 2962 | } |
3dfed10e | 2963 | |
2c00a5a8 | 2964 | err.emit(); |
ea8adc8c | 2965 | } |
a7813a04 | 2966 | } |
1a4d82fc | 2967 | |
a7813a04 XL |
2968 | /// Given the bounds on an object, determines what single region bound (if any) we can |
2969 | /// use to summarize this type. The basic idea is that we will use the bound the user | |
2970 | /// provided, if they provided one, and otherwise search the supertypes of trait bounds | |
2971 | /// for region bounds. It may be that we can derive no bound at all, in which case | |
2972 | /// we return `None`. | |
dfeec247 XL |
2973 | fn compute_object_lifetime_bound( |
2974 | &self, | |
a7813a04 | 2975 | span: Span, |
cdc7bbd5 | 2976 | existential_predicates: &'tcx ty::List<ty::Binder<'tcx, ty::ExistentialPredicate<'tcx>>>, |
dfeec247 | 2977 | ) -> Option<ty::Region<'tcx>> // if None, use the default |
a7813a04 XL |
2978 | { |
2979 | let tcx = self.tcx(); | |
85aaf69f | 2980 | |
dfeec247 | 2981 | debug!("compute_opt_region_bound(existential_predicates={:?})", existential_predicates); |
1a4d82fc | 2982 | |
a7813a04 XL |
2983 | // No explicit region bound specified. Therefore, examine trait |
2984 | // bounds and see if we can derive region bounds from those. | |
dfeec247 | 2985 | let derived_region_bounds = object_region_bounds(tcx, existential_predicates); |
1a4d82fc | 2986 | |
a7813a04 XL |
2987 | // If there are no derived region bounds, then report back that we |
2988 | // can find no region bound. The caller will use the default. | |
2989 | if derived_region_bounds.is_empty() { | |
2990 | return None; | |
2991 | } | |
1a4d82fc | 2992 | |
a7813a04 XL |
2993 | // If any of the derived region bounds are 'static, that is always |
2994 | // the best choice. | |
5099ac24 | 2995 | if derived_region_bounds.iter().any(|r| r.is_static()) { |
48663c56 | 2996 | return Some(tcx.lifetimes.re_static); |
a7813a04 | 2997 | } |
1a4d82fc | 2998 | |
a7813a04 XL |
2999 | // Determine whether there is exactly one unique region in the set |
3000 | // of derived region bounds. If so, use that. Otherwise, report an | |
3001 | // error. | |
3002 | let r = derived_region_bounds[0]; | |
3003 | if derived_region_bounds[1..].iter().any(|r1| r != *r1) { | |
1b1a35ee | 3004 | tcx.sess.emit_err(AmbiguousLifetimeBound { span }); |
a7813a04 | 3005 | } |
ba9703b0 | 3006 | Some(r) |
1a4d82fc | 3007 | } |
a2a8927a | 3008 | |
064997fb | 3009 | /// Make sure that we are in the condition to suggest the blanket implementation. |
f2b60f7d | 3010 | fn maybe_lint_blanket_trait_impl(&self, self_ty: &hir::Ty<'_>, diag: &mut Diagnostic) { |
064997fb FG |
3011 | let tcx = self.tcx(); |
3012 | let parent_id = tcx.hir().get_parent_item(self_ty.hir_id); | |
3013 | if let hir::Node::Item(hir::Item { | |
3014 | kind: | |
3015 | hir::ItemKind::Impl(hir::Impl { | |
3016 | self_ty: impl_self_ty, of_trait: Some(of_trait_ref), generics, .. | |
3017 | }), | |
3018 | .. | |
3019 | }) = tcx.hir().get_by_def_id(parent_id) && self_ty.hir_id == impl_self_ty.hir_id | |
3020 | { | |
3021 | if !of_trait_ref.trait_def_id().map_or(false, |def_id| def_id.is_local()) { | |
3022 | return; | |
3023 | } | |
3024 | let of_trait_span = of_trait_ref.path.span; | |
3025 | // make sure that we are not calling unwrap to abort during the compilation | |
3026 | let Ok(impl_trait_name) = tcx.sess.source_map().span_to_snippet(self_ty.span) else { return; }; | |
3027 | let Ok(of_trait_name) = tcx.sess.source_map().span_to_snippet(of_trait_span) else { return; }; | |
3028 | // check if the trait has generics, to make a correct suggestion | |
3029 | let param_name = generics.params.next_type_param_name(None); | |
3030 | ||
3031 | let add_generic_sugg = if let Some(span) = generics.span_for_param_suggestion() { | |
3032 | (span, format!(", {}: {}", param_name, impl_trait_name)) | |
3033 | } else { | |
3034 | (generics.span, format!("<{}: {}>", param_name, impl_trait_name)) | |
3035 | }; | |
3036 | diag.multipart_suggestion( | |
3037 | format!("alternatively use a blanket \ | |
3038 | implementation to implement `{of_trait_name}` for \ | |
3039 | all types that also implement `{impl_trait_name}`"), | |
3040 | vec![ | |
3041 | (self_ty.span, param_name), | |
3042 | add_generic_sugg, | |
3043 | ], | |
3044 | Applicability::MaybeIncorrect, | |
3045 | ); | |
3046 | } | |
3047 | } | |
3048 | ||
a2a8927a XL |
3049 | fn maybe_lint_bare_trait(&self, self_ty: &hir::Ty<'_>, in_path: bool) { |
3050 | let tcx = self.tcx(); | |
3051 | if let hir::TyKind::TraitObject([poly_trait_ref, ..], _, TraitObjectSyntax::None) = | |
3052 | self_ty.kind | |
3053 | { | |
3054 | let needs_bracket = in_path | |
3055 | && !tcx | |
3056 | .sess | |
3057 | .source_map() | |
3058 | .span_to_prev_source(self_ty.span) | |
3059 | .ok() | |
3060 | .map_or(false, |s| s.trim_end().ends_with('<')); | |
3061 | ||
3062 | let is_global = poly_trait_ref.trait_ref.path.is_global(); | |
3063 | let sugg = Vec::from_iter([ | |
3064 | ( | |
3065 | self_ty.span.shrink_to_lo(), | |
3066 | format!( | |
3067 | "{}dyn {}", | |
3068 | if needs_bracket { "<" } else { "" }, | |
3069 | if is_global { "(" } else { "" }, | |
3070 | ), | |
3071 | ), | |
3072 | ( | |
3073 | self_ty.span.shrink_to_hi(), | |
3074 | format!( | |
3075 | "{}{}", | |
3076 | if is_global { ")" } else { "" }, | |
3077 | if needs_bracket { ">" } else { "" }, | |
3078 | ), | |
3079 | ), | |
3080 | ]); | |
3081 | if self_ty.span.edition() >= Edition::Edition2021 { | |
3082 | let msg = "trait objects must include the `dyn` keyword"; | |
3083 | let label = "add `dyn` keyword before this trait"; | |
064997fb FG |
3084 | let mut diag = |
3085 | rustc_errors::struct_span_err!(tcx.sess, self_ty.span, E0782, "{}", msg); | |
3086 | diag.multipart_suggestion_verbose(label, sugg, Applicability::MachineApplicable); | |
3087 | // check if the impl trait that we are considering is a impl of a local trait | |
3088 | self.maybe_lint_blanket_trait_impl(&self_ty, &mut diag); | |
3089 | diag.emit(); | |
a2a8927a XL |
3090 | } else { |
3091 | let msg = "trait objects without an explicit `dyn` are deprecated"; | |
3092 | tcx.struct_span_lint_hir( | |
3093 | BARE_TRAIT_OBJECTS, | |
3094 | self_ty.hir_id, | |
3095 | self_ty.span, | |
3096 | |lint| { | |
064997fb FG |
3097 | let mut diag = lint.build(msg); |
3098 | diag.multipart_suggestion_verbose( | |
3099 | "use `dyn`", | |
3100 | sugg, | |
3101 | Applicability::MachineApplicable, | |
3102 | ); | |
f2b60f7d | 3103 | self.maybe_lint_blanket_trait_impl(&self_ty, &mut diag); |
064997fb | 3104 | diag.emit(); |
a2a8927a XL |
3105 | }, |
3106 | ); | |
3107 | } | |
3108 | } | |
3109 | } | |
1a4d82fc | 3110 | } |