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Commit | Line | Data |
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29967ef6 | 1 | use crate::astconv::{ |
fc512014 | 2 | AstConv, CreateSubstsForGenericArgsCtxt, ExplicitLateBound, GenericArgCountMismatch, |
5869c6ff | 3 | GenericArgCountResult, IsMethodCall, PathSeg, |
29967ef6 XL |
4 | }; |
5 | use crate::check::callee::{self, DeferredCallResolution}; | |
6 | use crate::check::method::{self, MethodCallee, SelfSource}; | |
7 | use crate::check::{BreakableCtxt, Diverges, Expectation, FallbackMode, FnCtxt, LocalTy}; | |
8 | ||
6a06907d | 9 | use rustc_ast::TraitObjectSyntax; |
29967ef6 XL |
10 | use rustc_data_structures::captures::Captures; |
11 | use rustc_data_structures::fx::FxHashSet; | |
12 | use rustc_errors::{Applicability, DiagnosticBuilder, ErrorReported}; | |
13 | use rustc_hir as hir; | |
14 | use rustc_hir::def::{CtorOf, DefKind, Res}; | |
15 | use rustc_hir::def_id::DefId; | |
16 | use rustc_hir::lang_items::LangItem; | |
6a06907d | 17 | use rustc_hir::{ExprKind, GenericArg, Node, QPath, TyKind}; |
29967ef6 XL |
18 | use rustc_infer::infer::canonical::{Canonical, OriginalQueryValues, QueryResponse}; |
19 | use rustc_infer::infer::error_reporting::TypeAnnotationNeeded::E0282; | |
20 | use rustc_infer::infer::{InferOk, InferResult}; | |
21 | use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow, AutoBorrowMutability}; | |
22 | use rustc_middle::ty::fold::TypeFoldable; | |
23 | use rustc_middle::ty::subst::{ | |
24 | self, GenericArgKind, InternalSubsts, Subst, SubstsRef, UserSelfTy, UserSubsts, | |
25 | }; | |
26 | use rustc_middle::ty::{ | |
27 | self, AdtKind, CanonicalUserType, DefIdTree, GenericParamDefKind, ToPolyTraitRef, ToPredicate, | |
28 | Ty, UserType, | |
29 | }; | |
30 | use rustc_session::lint; | |
6a06907d XL |
31 | use rustc_session::lint::builtin::BARE_TRAIT_OBJECTS; |
32 | use rustc_session::parse::feature_err; | |
29967ef6 XL |
33 | use rustc_span::source_map::{original_sp, DUMMY_SP}; |
34 | use rustc_span::symbol::{kw, sym, Ident}; | |
35 | use rustc_span::{self, BytePos, MultiSpan, Span}; | |
6a06907d | 36 | use rustc_span::{hygiene::DesugaringKind, Symbol}; |
29967ef6 XL |
37 | use rustc_trait_selection::infer::InferCtxtExt as _; |
38 | use rustc_trait_selection::opaque_types::InferCtxtExt as _; | |
39 | use rustc_trait_selection::traits::error_reporting::InferCtxtExt as _; | |
40 | use rustc_trait_selection::traits::{ | |
41 | self, ObligationCauseCode, StatementAsExpression, TraitEngine, TraitEngineExt, | |
42 | }; | |
43 | ||
44 | use std::collections::hash_map::Entry; | |
cdc7bbd5 | 45 | use std::iter; |
29967ef6 XL |
46 | use std::slice; |
47 | ||
48 | impl<'a, 'tcx> FnCtxt<'a, 'tcx> { | |
49 | /// Produces warning on the given node, if the current point in the | |
50 | /// function is unreachable, and there hasn't been another warning. | |
51 | pub(in super::super) fn warn_if_unreachable(&self, id: hir::HirId, span: Span, kind: &str) { | |
52 | // FIXME: Combine these two 'if' expressions into one once | |
53 | // let chains are implemented | |
54 | if let Diverges::Always { span: orig_span, custom_note } = self.diverges.get() { | |
55 | // If span arose from a desugaring of `if` or `while`, then it is the condition itself, | |
56 | // which diverges, that we are about to lint on. This gives suboptimal diagnostics. | |
57 | // Instead, stop here so that the `if`- or `while`-expression's block is linted instead. | |
58 | if !span.is_desugaring(DesugaringKind::CondTemporary) | |
59 | && !span.is_desugaring(DesugaringKind::Async) | |
60 | && !orig_span.is_desugaring(DesugaringKind::Await) | |
61 | { | |
62 | self.diverges.set(Diverges::WarnedAlways); | |
63 | ||
64 | debug!("warn_if_unreachable: id={:?} span={:?} kind={}", id, span, kind); | |
65 | ||
66 | self.tcx().struct_span_lint_hir(lint::builtin::UNREACHABLE_CODE, id, span, |lint| { | |
67 | let msg = format!("unreachable {}", kind); | |
68 | lint.build(&msg) | |
69 | .span_label(span, &msg) | |
70 | .span_label( | |
71 | orig_span, | |
72 | custom_note | |
73 | .unwrap_or("any code following this expression is unreachable"), | |
74 | ) | |
75 | .emit(); | |
76 | }) | |
77 | } | |
78 | } | |
79 | } | |
80 | ||
81 | /// Resolves type and const variables in `ty` if possible. Unlike the infcx | |
82 | /// version (resolve_vars_if_possible), this version will | |
83 | /// also select obligations if it seems useful, in an effort | |
84 | /// to get more type information. | |
85 | pub(in super::super) fn resolve_vars_with_obligations(&self, mut ty: Ty<'tcx>) -> Ty<'tcx> { | |
86 | debug!("resolve_vars_with_obligations(ty={:?})", ty); | |
87 | ||
88 | // No Infer()? Nothing needs doing. | |
89 | if !ty.has_infer_types_or_consts() { | |
90 | debug!("resolve_vars_with_obligations: ty={:?}", ty); | |
91 | return ty; | |
92 | } | |
93 | ||
94 | // If `ty` is a type variable, see whether we already know what it is. | |
fc512014 | 95 | ty = self.resolve_vars_if_possible(ty); |
29967ef6 XL |
96 | if !ty.has_infer_types_or_consts() { |
97 | debug!("resolve_vars_with_obligations: ty={:?}", ty); | |
98 | return ty; | |
99 | } | |
100 | ||
101 | // If not, try resolving pending obligations as much as | |
102 | // possible. This can help substantially when there are | |
103 | // indirect dependencies that don't seem worth tracking | |
104 | // precisely. | |
105 | self.select_obligations_where_possible(false, |_| {}); | |
fc512014 | 106 | ty = self.resolve_vars_if_possible(ty); |
29967ef6 XL |
107 | |
108 | debug!("resolve_vars_with_obligations: ty={:?}", ty); | |
109 | ty | |
110 | } | |
111 | ||
112 | pub(in super::super) fn record_deferred_call_resolution( | |
113 | &self, | |
114 | closure_def_id: DefId, | |
115 | r: DeferredCallResolution<'tcx>, | |
116 | ) { | |
117 | let mut deferred_call_resolutions = self.deferred_call_resolutions.borrow_mut(); | |
118 | deferred_call_resolutions.entry(closure_def_id).or_default().push(r); | |
119 | } | |
120 | ||
121 | pub(in super::super) fn remove_deferred_call_resolutions( | |
122 | &self, | |
123 | closure_def_id: DefId, | |
124 | ) -> Vec<DeferredCallResolution<'tcx>> { | |
125 | let mut deferred_call_resolutions = self.deferred_call_resolutions.borrow_mut(); | |
126 | deferred_call_resolutions.remove(&closure_def_id).unwrap_or_default() | |
127 | } | |
128 | ||
129 | pub fn tag(&self) -> String { | |
130 | format!("{:p}", self) | |
131 | } | |
132 | ||
133 | pub fn local_ty(&self, span: Span, nid: hir::HirId) -> LocalTy<'tcx> { | |
134 | self.locals.borrow().get(&nid).cloned().unwrap_or_else(|| { | |
135 | span_bug!(span, "no type for local variable {}", self.tcx.hir().node_to_string(nid)) | |
136 | }) | |
137 | } | |
138 | ||
139 | #[inline] | |
140 | pub fn write_ty(&self, id: hir::HirId, ty: Ty<'tcx>) { | |
fc512014 | 141 | debug!("write_ty({:?}, {:?}) in fcx {}", id, self.resolve_vars_if_possible(ty), self.tag()); |
29967ef6 XL |
142 | self.typeck_results.borrow_mut().node_types_mut().insert(id, ty); |
143 | ||
144 | if ty.references_error() { | |
145 | self.has_errors.set(true); | |
146 | self.set_tainted_by_errors(); | |
147 | } | |
148 | } | |
149 | ||
150 | pub fn write_field_index(&self, hir_id: hir::HirId, index: usize) { | |
151 | self.typeck_results.borrow_mut().field_indices_mut().insert(hir_id, index); | |
152 | } | |
153 | ||
154 | pub(in super::super) fn write_resolution( | |
155 | &self, | |
156 | hir_id: hir::HirId, | |
157 | r: Result<(DefKind, DefId), ErrorReported>, | |
158 | ) { | |
159 | self.typeck_results.borrow_mut().type_dependent_defs_mut().insert(hir_id, r); | |
160 | } | |
161 | ||
162 | pub fn write_method_call(&self, hir_id: hir::HirId, method: MethodCallee<'tcx>) { | |
163 | debug!("write_method_call(hir_id={:?}, method={:?})", hir_id, method); | |
164 | self.write_resolution(hir_id, Ok((DefKind::AssocFn, method.def_id))); | |
165 | self.write_substs(hir_id, method.substs); | |
166 | ||
167 | // When the method is confirmed, the `method.substs` includes | |
168 | // parameters from not just the method, but also the impl of | |
169 | // the method -- in particular, the `Self` type will be fully | |
170 | // resolved. However, those are not something that the "user | |
171 | // specified" -- i.e., those types come from the inferred type | |
172 | // of the receiver, not something the user wrote. So when we | |
173 | // create the user-substs, we want to replace those earlier | |
174 | // types with just the types that the user actually wrote -- | |
175 | // that is, those that appear on the *method itself*. | |
176 | // | |
177 | // As an example, if the user wrote something like | |
178 | // `foo.bar::<u32>(...)` -- the `Self` type here will be the | |
179 | // type of `foo` (possibly adjusted), but we don't want to | |
180 | // include that. We want just the `[_, u32]` part. | |
181 | if !method.substs.is_noop() { | |
182 | let method_generics = self.tcx.generics_of(method.def_id); | |
183 | if !method_generics.params.is_empty() { | |
184 | let user_type_annotation = self.infcx.probe(|_| { | |
185 | let user_substs = UserSubsts { | |
186 | substs: InternalSubsts::for_item(self.tcx, method.def_id, |param, _| { | |
187 | let i = param.index as usize; | |
188 | if i < method_generics.parent_count { | |
189 | self.infcx.var_for_def(DUMMY_SP, param) | |
190 | } else { | |
191 | method.substs[i] | |
192 | } | |
193 | }), | |
194 | user_self_ty: None, // not relevant here | |
195 | }; | |
196 | ||
fc512014 | 197 | self.infcx.canonicalize_user_type_annotation(UserType::TypeOf( |
29967ef6 XL |
198 | method.def_id, |
199 | user_substs, | |
200 | )) | |
201 | }); | |
202 | ||
203 | debug!("write_method_call: user_type_annotation={:?}", user_type_annotation); | |
204 | self.write_user_type_annotation(hir_id, user_type_annotation); | |
205 | } | |
206 | } | |
207 | } | |
208 | ||
209 | pub fn write_substs(&self, node_id: hir::HirId, substs: SubstsRef<'tcx>) { | |
210 | if !substs.is_noop() { | |
211 | debug!("write_substs({:?}, {:?}) in fcx {}", node_id, substs, self.tag()); | |
212 | ||
213 | self.typeck_results.borrow_mut().node_substs_mut().insert(node_id, substs); | |
214 | } | |
215 | } | |
216 | ||
217 | /// Given the substs that we just converted from the HIR, try to | |
218 | /// canonicalize them and store them as user-given substitutions | |
219 | /// (i.e., substitutions that must be respected by the NLL check). | |
220 | /// | |
221 | /// This should be invoked **before any unifications have | |
222 | /// occurred**, so that annotations like `Vec<_>` are preserved | |
223 | /// properly. | |
224 | pub fn write_user_type_annotation_from_substs( | |
225 | &self, | |
226 | hir_id: hir::HirId, | |
227 | def_id: DefId, | |
228 | substs: SubstsRef<'tcx>, | |
229 | user_self_ty: Option<UserSelfTy<'tcx>>, | |
230 | ) { | |
231 | debug!( | |
232 | "write_user_type_annotation_from_substs: hir_id={:?} def_id={:?} substs={:?} \ | |
233 | user_self_ty={:?} in fcx {}", | |
234 | hir_id, | |
235 | def_id, | |
236 | substs, | |
237 | user_self_ty, | |
238 | self.tag(), | |
239 | ); | |
240 | ||
241 | if Self::can_contain_user_lifetime_bounds((substs, user_self_ty)) { | |
fc512014 | 242 | let canonicalized = self.infcx.canonicalize_user_type_annotation(UserType::TypeOf( |
29967ef6 XL |
243 | def_id, |
244 | UserSubsts { substs, user_self_ty }, | |
245 | )); | |
246 | debug!("write_user_type_annotation_from_substs: canonicalized={:?}", canonicalized); | |
247 | self.write_user_type_annotation(hir_id, canonicalized); | |
248 | } | |
249 | } | |
250 | ||
251 | pub fn write_user_type_annotation( | |
252 | &self, | |
253 | hir_id: hir::HirId, | |
254 | canonical_user_type_annotation: CanonicalUserType<'tcx>, | |
255 | ) { | |
256 | debug!( | |
257 | "write_user_type_annotation: hir_id={:?} canonical_user_type_annotation={:?} tag={}", | |
258 | hir_id, | |
259 | canonical_user_type_annotation, | |
260 | self.tag(), | |
261 | ); | |
262 | ||
263 | if !canonical_user_type_annotation.is_identity() { | |
264 | self.typeck_results | |
265 | .borrow_mut() | |
266 | .user_provided_types_mut() | |
267 | .insert(hir_id, canonical_user_type_annotation); | |
268 | } else { | |
269 | debug!("write_user_type_annotation: skipping identity substs"); | |
270 | } | |
271 | } | |
272 | ||
273 | pub fn apply_adjustments(&self, expr: &hir::Expr<'_>, adj: Vec<Adjustment<'tcx>>) { | |
274 | debug!("apply_adjustments(expr={:?}, adj={:?})", expr, adj); | |
275 | ||
276 | if adj.is_empty() { | |
277 | return; | |
278 | } | |
279 | ||
280 | let autoborrow_mut = adj.iter().any(|adj| { | |
5869c6ff XL |
281 | matches!( |
282 | adj, | |
283 | &Adjustment { | |
284 | kind: Adjust::Borrow(AutoBorrow::Ref(_, AutoBorrowMutability::Mut { .. })), | |
285 | .. | |
286 | } | |
287 | ) | |
29967ef6 XL |
288 | }); |
289 | ||
290 | match self.typeck_results.borrow_mut().adjustments_mut().entry(expr.hir_id) { | |
291 | Entry::Vacant(entry) => { | |
292 | entry.insert(adj); | |
293 | } | |
294 | Entry::Occupied(mut entry) => { | |
295 | debug!(" - composing on top of {:?}", entry.get()); | |
296 | match (&entry.get()[..], &adj[..]) { | |
297 | // Applying any adjustment on top of a NeverToAny | |
298 | // is a valid NeverToAny adjustment, because it can't | |
299 | // be reached. | |
300 | (&[Adjustment { kind: Adjust::NeverToAny, .. }], _) => return, | |
301 | (&[ | |
302 | Adjustment { kind: Adjust::Deref(_), .. }, | |
303 | Adjustment { kind: Adjust::Borrow(AutoBorrow::Ref(..)), .. }, | |
304 | ], &[ | |
305 | Adjustment { kind: Adjust::Deref(_), .. }, | |
306 | .. // Any following adjustments are allowed. | |
307 | ]) => { | |
308 | // A reborrow has no effect before a dereference. | |
309 | } | |
310 | // FIXME: currently we never try to compose autoderefs | |
311 | // and ReifyFnPointer/UnsafeFnPointer, but we could. | |
312 | _ => | |
313 | bug!("while adjusting {:?}, can't compose {:?} and {:?}", | |
314 | expr, entry.get(), adj) | |
315 | }; | |
316 | *entry.get_mut() = adj; | |
317 | } | |
318 | } | |
319 | ||
320 | // If there is an mutable auto-borrow, it is equivalent to `&mut <expr>`. | |
321 | // In this case implicit use of `Deref` and `Index` within `<expr>` should | |
322 | // instead be `DerefMut` and `IndexMut`, so fix those up. | |
323 | if autoborrow_mut { | |
324 | self.convert_place_derefs_to_mutable(expr); | |
325 | } | |
326 | } | |
327 | ||
328 | /// Basically whenever we are converting from a type scheme into | |
329 | /// the fn body space, we always want to normalize associated | |
330 | /// types as well. This function combines the two. | |
fc512014 | 331 | fn instantiate_type_scheme<T>(&self, span: Span, substs: SubstsRef<'tcx>, value: T) -> T |
29967ef6 XL |
332 | where |
333 | T: TypeFoldable<'tcx>, | |
334 | { | |
fc512014 | 335 | debug!("instantiate_type_scheme(value={:?}, substs={:?})", value, substs); |
29967ef6 | 336 | let value = value.subst(self.tcx, substs); |
fc512014 XL |
337 | let result = self.normalize_associated_types_in(span, value); |
338 | debug!("instantiate_type_scheme = {:?}", result); | |
29967ef6 XL |
339 | result |
340 | } | |
341 | ||
342 | /// As `instantiate_type_scheme`, but for the bounds found in a | |
343 | /// generic type scheme. | |
344 | pub(in super::super) fn instantiate_bounds( | |
345 | &self, | |
346 | span: Span, | |
347 | def_id: DefId, | |
348 | substs: SubstsRef<'tcx>, | |
349 | ) -> (ty::InstantiatedPredicates<'tcx>, Vec<Span>) { | |
350 | let bounds = self.tcx.predicates_of(def_id); | |
351 | let spans: Vec<Span> = bounds.predicates.iter().map(|(_, span)| *span).collect(); | |
352 | let result = bounds.instantiate(self.tcx, substs); | |
fc512014 | 353 | let result = self.normalize_associated_types_in(span, result); |
29967ef6 XL |
354 | debug!( |
355 | "instantiate_bounds(bounds={:?}, substs={:?}) = {:?}, {:?}", | |
356 | bounds, substs, result, spans, | |
357 | ); | |
358 | (result, spans) | |
359 | } | |
360 | ||
361 | /// Replaces the opaque types from the given value with type variables, | |
362 | /// and records the `OpaqueTypeMap` for later use during writeback. See | |
363 | /// `InferCtxt::instantiate_opaque_types` for more details. | |
364 | pub(in super::super) fn instantiate_opaque_types_from_value<T: TypeFoldable<'tcx>>( | |
365 | &self, | |
366 | parent_id: hir::HirId, | |
fc512014 | 367 | value: T, |
29967ef6 | 368 | value_span: Span, |
6a06907d | 369 | feature: Option<Symbol>, |
29967ef6 XL |
370 | ) -> T { |
371 | let parent_def_id = self.tcx.hir().local_def_id(parent_id); | |
372 | debug!( | |
373 | "instantiate_opaque_types_from_value(parent_def_id={:?}, value={:?})", | |
374 | parent_def_id, value | |
375 | ); | |
376 | ||
377 | let (value, opaque_type_map) = | |
378 | self.register_infer_ok_obligations(self.instantiate_opaque_types( | |
379 | parent_def_id, | |
380 | self.body_id, | |
381 | self.param_env, | |
382 | value, | |
383 | value_span, | |
384 | )); | |
385 | ||
386 | let mut opaque_types = self.opaque_types.borrow_mut(); | |
387 | let mut opaque_types_vars = self.opaque_types_vars.borrow_mut(); | |
6a06907d | 388 | |
29967ef6 | 389 | for (ty, decl) in opaque_type_map { |
6a06907d XL |
390 | if let Some(feature) = feature { |
391 | if let hir::OpaqueTyOrigin::TyAlias = decl.origin { | |
392 | if !self.tcx.features().enabled(feature) { | |
393 | feature_err( | |
394 | &self.tcx.sess.parse_sess, | |
395 | feature, | |
396 | value_span, | |
397 | "type alias impl trait is not permitted here", | |
398 | ) | |
399 | .emit(); | |
400 | } | |
401 | } | |
402 | } | |
29967ef6 XL |
403 | let _ = opaque_types.insert(ty, decl); |
404 | let _ = opaque_types_vars.insert(decl.concrete_ty, decl.opaque_type); | |
405 | } | |
406 | ||
407 | value | |
408 | } | |
409 | ||
fc512014 | 410 | pub(in super::super) fn normalize_associated_types_in<T>(&self, span: Span, value: T) -> T |
29967ef6 XL |
411 | where |
412 | T: TypeFoldable<'tcx>, | |
413 | { | |
414 | self.inh.normalize_associated_types_in(span, self.body_id, self.param_env, value) | |
415 | } | |
416 | ||
417 | pub(in super::super) fn normalize_associated_types_in_as_infer_ok<T>( | |
418 | &self, | |
419 | span: Span, | |
fc512014 | 420 | value: T, |
29967ef6 XL |
421 | ) -> InferOk<'tcx, T> |
422 | where | |
423 | T: TypeFoldable<'tcx>, | |
424 | { | |
425 | self.inh.partially_normalize_associated_types_in(span, self.body_id, self.param_env, value) | |
426 | } | |
427 | ||
428 | pub fn require_type_meets( | |
429 | &self, | |
430 | ty: Ty<'tcx>, | |
431 | span: Span, | |
432 | code: traits::ObligationCauseCode<'tcx>, | |
433 | def_id: DefId, | |
434 | ) { | |
435 | self.register_bound(ty, def_id, traits::ObligationCause::new(span, self.body_id, code)); | |
436 | } | |
437 | ||
438 | pub fn require_type_is_sized( | |
439 | &self, | |
440 | ty: Ty<'tcx>, | |
441 | span: Span, | |
442 | code: traits::ObligationCauseCode<'tcx>, | |
443 | ) { | |
444 | if !ty.references_error() { | |
445 | let lang_item = self.tcx.require_lang_item(LangItem::Sized, None); | |
446 | self.require_type_meets(ty, span, code, lang_item); | |
447 | } | |
448 | } | |
449 | ||
450 | pub fn require_type_is_sized_deferred( | |
451 | &self, | |
452 | ty: Ty<'tcx>, | |
453 | span: Span, | |
454 | code: traits::ObligationCauseCode<'tcx>, | |
455 | ) { | |
456 | if !ty.references_error() { | |
457 | self.deferred_sized_obligations.borrow_mut().push((ty, span, code)); | |
458 | } | |
459 | } | |
460 | ||
461 | pub fn register_bound( | |
462 | &self, | |
463 | ty: Ty<'tcx>, | |
464 | def_id: DefId, | |
465 | cause: traits::ObligationCause<'tcx>, | |
466 | ) { | |
467 | if !ty.references_error() { | |
468 | self.fulfillment_cx.borrow_mut().register_bound( | |
469 | self, | |
470 | self.param_env, | |
471 | ty, | |
472 | def_id, | |
473 | cause, | |
474 | ); | |
475 | } | |
476 | } | |
477 | ||
478 | pub fn to_ty(&self, ast_t: &hir::Ty<'_>) -> Ty<'tcx> { | |
6a06907d | 479 | let t = <dyn AstConv<'_>>::ast_ty_to_ty(self, ast_t); |
29967ef6 XL |
480 | self.register_wf_obligation(t.into(), ast_t.span, traits::MiscObligation); |
481 | t | |
482 | } | |
483 | ||
484 | pub fn to_ty_saving_user_provided_ty(&self, ast_ty: &hir::Ty<'_>) -> Ty<'tcx> { | |
485 | let ty = self.to_ty(ast_ty); | |
486 | debug!("to_ty_saving_user_provided_ty: ty={:?}", ty); | |
487 | ||
488 | if Self::can_contain_user_lifetime_bounds(ty) { | |
fc512014 | 489 | let c_ty = self.infcx.canonicalize_response(UserType::Ty(ty)); |
29967ef6 XL |
490 | debug!("to_ty_saving_user_provided_ty: c_ty={:?}", c_ty); |
491 | self.typeck_results.borrow_mut().user_provided_types_mut().insert(ast_ty.hir_id, c_ty); | |
492 | } | |
493 | ||
494 | ty | |
495 | } | |
496 | ||
497 | pub fn to_const(&self, ast_c: &hir::AnonConst) -> &'tcx ty::Const<'tcx> { | |
498 | let const_def_id = self.tcx.hir().local_def_id(ast_c.hir_id); | |
499 | let c = ty::Const::from_anon_const(self.tcx, const_def_id); | |
500 | self.register_wf_obligation( | |
501 | c.into(), | |
502 | self.tcx.hir().span(ast_c.hir_id), | |
503 | ObligationCauseCode::MiscObligation, | |
504 | ); | |
505 | c | |
506 | } | |
507 | ||
508 | pub fn const_arg_to_const( | |
509 | &self, | |
510 | ast_c: &hir::AnonConst, | |
511 | param_def_id: DefId, | |
512 | ) -> &'tcx ty::Const<'tcx> { | |
513 | let const_def = ty::WithOptConstParam { | |
514 | did: self.tcx.hir().local_def_id(ast_c.hir_id), | |
515 | const_param_did: Some(param_def_id), | |
516 | }; | |
517 | let c = ty::Const::from_opt_const_arg_anon_const(self.tcx, const_def); | |
518 | self.register_wf_obligation( | |
519 | c.into(), | |
520 | self.tcx.hir().span(ast_c.hir_id), | |
521 | ObligationCauseCode::MiscObligation, | |
522 | ); | |
523 | c | |
524 | } | |
525 | ||
526 | // If the type given by the user has free regions, save it for later, since | |
527 | // NLL would like to enforce those. Also pass in types that involve | |
528 | // projections, since those can resolve to `'static` bounds (modulo #54940, | |
529 | // which hopefully will be fixed by the time you see this comment, dear | |
530 | // reader, although I have my doubts). Also pass in types with inference | |
531 | // types, because they may be repeated. Other sorts of things are already | |
532 | // sufficiently enforced with erased regions. =) | |
533 | fn can_contain_user_lifetime_bounds<T>(t: T) -> bool | |
534 | where | |
535 | T: TypeFoldable<'tcx>, | |
536 | { | |
537 | t.has_free_regions() || t.has_projections() || t.has_infer_types() | |
538 | } | |
539 | ||
540 | pub fn node_ty(&self, id: hir::HirId) -> Ty<'tcx> { | |
541 | match self.typeck_results.borrow().node_types().get(id) { | |
542 | Some(&t) => t, | |
543 | None if self.is_tainted_by_errors() => self.tcx.ty_error(), | |
544 | None => { | |
545 | bug!( | |
546 | "no type for node {}: {} in fcx {}", | |
547 | id, | |
548 | self.tcx.hir().node_to_string(id), | |
549 | self.tag() | |
550 | ); | |
551 | } | |
552 | } | |
553 | } | |
554 | ||
555 | /// Registers an obligation for checking later, during regionck, that `arg` is well-formed. | |
556 | pub fn register_wf_obligation( | |
557 | &self, | |
558 | arg: subst::GenericArg<'tcx>, | |
559 | span: Span, | |
560 | code: traits::ObligationCauseCode<'tcx>, | |
561 | ) { | |
562 | // WF obligations never themselves fail, so no real need to give a detailed cause: | |
563 | let cause = traits::ObligationCause::new(span, self.body_id, code); | |
564 | self.register_predicate(traits::Obligation::new( | |
565 | cause, | |
566 | self.param_env, | |
5869c6ff | 567 | ty::PredicateKind::WellFormed(arg).to_predicate(self.tcx), |
29967ef6 XL |
568 | )); |
569 | } | |
570 | ||
571 | /// Registers obligations that all `substs` are well-formed. | |
572 | pub fn add_wf_bounds(&self, substs: SubstsRef<'tcx>, expr: &hir::Expr<'_>) { | |
573 | for arg in substs.iter().filter(|arg| { | |
574 | matches!(arg.unpack(), GenericArgKind::Type(..) | GenericArgKind::Const(..)) | |
575 | }) { | |
576 | self.register_wf_obligation(arg, expr.span, traits::MiscObligation); | |
577 | } | |
578 | } | |
579 | ||
580 | /// Given a fully substituted set of bounds (`generic_bounds`), and the values with which each | |
581 | /// type/region parameter was instantiated (`substs`), creates and registers suitable | |
582 | /// trait/region obligations. | |
583 | /// | |
584 | /// For example, if there is a function: | |
585 | /// | |
586 | /// ``` | |
587 | /// fn foo<'a,T:'a>(...) | |
588 | /// ``` | |
589 | /// | |
590 | /// and a reference: | |
591 | /// | |
592 | /// ``` | |
593 | /// let f = foo; | |
594 | /// ``` | |
595 | /// | |
596 | /// Then we will create a fresh region variable `'$0` and a fresh type variable `$1` for `'a` | |
597 | /// and `T`. This routine will add a region obligation `$1:'$0` and register it locally. | |
598 | pub fn add_obligations_for_parameters( | |
599 | &self, | |
600 | cause: traits::ObligationCause<'tcx>, | |
601 | predicates: ty::InstantiatedPredicates<'tcx>, | |
602 | ) { | |
603 | assert!(!predicates.has_escaping_bound_vars()); | |
604 | ||
605 | debug!("add_obligations_for_parameters(predicates={:?})", predicates); | |
606 | ||
607 | for obligation in traits::predicates_for_generics(cause, self.param_env, predicates) { | |
608 | self.register_predicate(obligation); | |
609 | } | |
610 | } | |
611 | ||
612 | // FIXME(arielb1): use this instead of field.ty everywhere | |
613 | // Only for fields! Returns <none> for methods> | |
614 | // Indifferent to privacy flags | |
615 | pub fn field_ty( | |
616 | &self, | |
617 | span: Span, | |
618 | field: &'tcx ty::FieldDef, | |
619 | substs: SubstsRef<'tcx>, | |
620 | ) -> Ty<'tcx> { | |
621 | self.normalize_associated_types_in(span, &field.ty(self.tcx, substs)) | |
622 | } | |
623 | ||
624 | pub(in super::super) fn resolve_generator_interiors(&self, def_id: DefId) { | |
625 | let mut generators = self.deferred_generator_interiors.borrow_mut(); | |
626 | for (body_id, interior, kind) in generators.drain(..) { | |
627 | self.select_obligations_where_possible(false, |_| {}); | |
628 | crate::check::generator_interior::resolve_interior( | |
629 | self, def_id, body_id, interior, kind, | |
630 | ); | |
631 | } | |
632 | } | |
633 | ||
634 | // Tries to apply a fallback to `ty` if it is an unsolved variable. | |
635 | // | |
636 | // - Unconstrained ints are replaced with `i32`. | |
637 | // | |
638 | // - Unconstrained floats are replaced with with `f64`. | |
639 | // | |
640 | // - Non-numerics get replaced with `!` when `#![feature(never_type_fallback)]` | |
641 | // is enabled. Otherwise, they are replaced with `()`. | |
642 | // | |
643 | // Fallback becomes very dubious if we have encountered type-checking errors. | |
644 | // In that case, fallback to Error. | |
645 | // The return value indicates whether fallback has occurred. | |
646 | pub(in super::super) fn fallback_if_possible(&self, ty: Ty<'tcx>, mode: FallbackMode) -> bool { | |
647 | use rustc_middle::ty::error::UnconstrainedNumeric::Neither; | |
648 | use rustc_middle::ty::error::UnconstrainedNumeric::{UnconstrainedFloat, UnconstrainedInt}; | |
649 | ||
650 | assert!(ty.is_ty_infer()); | |
651 | let fallback = match self.type_is_unconstrained_numeric(ty) { | |
652 | _ if self.is_tainted_by_errors() => self.tcx().ty_error(), | |
653 | UnconstrainedInt => self.tcx.types.i32, | |
654 | UnconstrainedFloat => self.tcx.types.f64, | |
655 | Neither if self.type_var_diverges(ty) => self.tcx.mk_diverging_default(), | |
656 | Neither => { | |
657 | // This type variable was created from the instantiation of an opaque | |
658 | // type. The fact that we're attempting to perform fallback for it | |
659 | // means that the function neither constrained it to a concrete | |
660 | // type, nor to the opaque type itself. | |
661 | // | |
662 | // For example, in this code: | |
663 | // | |
664 | //``` | |
665 | // type MyType = impl Copy; | |
666 | // fn defining_use() -> MyType { true } | |
667 | // fn other_use() -> MyType { defining_use() } | |
668 | // ``` | |
669 | // | |
670 | // `defining_use` will constrain the instantiated inference | |
671 | // variable to `bool`, while `other_use` will constrain | |
672 | // the instantiated inference variable to `MyType`. | |
673 | // | |
674 | // When we process opaque types during writeback, we | |
675 | // will handle cases like `other_use`, and not count | |
676 | // them as defining usages | |
677 | // | |
678 | // However, we also need to handle cases like this: | |
679 | // | |
680 | // ```rust | |
681 | // pub type Foo = impl Copy; | |
682 | // fn produce() -> Option<Foo> { | |
683 | // None | |
684 | // } | |
685 | // ``` | |
686 | // | |
687 | // In the above snippet, the inference variable created by | |
688 | // instantiating `Option<Foo>` will be completely unconstrained. | |
689 | // We treat this as a non-defining use by making the inference | |
690 | // variable fall back to the opaque type itself. | |
691 | if let FallbackMode::All = mode { | |
692 | if let Some(opaque_ty) = self.opaque_types_vars.borrow().get(ty) { | |
693 | debug!( | |
694 | "fallback_if_possible: falling back opaque type var {:?} to {:?}", | |
695 | ty, opaque_ty | |
696 | ); | |
697 | *opaque_ty | |
698 | } else { | |
699 | return false; | |
700 | } | |
701 | } else { | |
702 | return false; | |
703 | } | |
704 | } | |
705 | }; | |
706 | debug!("fallback_if_possible: defaulting `{:?}` to `{:?}`", ty, fallback); | |
707 | self.demand_eqtype(rustc_span::DUMMY_SP, ty, fallback); | |
708 | true | |
709 | } | |
710 | ||
711 | pub(in super::super) fn select_all_obligations_or_error(&self) { | |
712 | debug!("select_all_obligations_or_error"); | |
713 | if let Err(errors) = self.fulfillment_cx.borrow_mut().select_all_or_error(&self) { | |
714 | self.report_fulfillment_errors(&errors, self.inh.body_id, false); | |
715 | } | |
716 | } | |
717 | ||
718 | /// Select as many obligations as we can at present. | |
719 | pub(in super::super) fn select_obligations_where_possible( | |
720 | &self, | |
721 | fallback_has_occurred: bool, | |
722 | mutate_fullfillment_errors: impl Fn(&mut Vec<traits::FulfillmentError<'tcx>>), | |
723 | ) { | |
724 | let result = self.fulfillment_cx.borrow_mut().select_where_possible(self); | |
725 | if let Err(mut errors) = result { | |
726 | mutate_fullfillment_errors(&mut errors); | |
727 | self.report_fulfillment_errors(&errors, self.inh.body_id, fallback_has_occurred); | |
728 | } | |
729 | } | |
730 | ||
731 | /// For the overloaded place expressions (`*x`, `x[3]`), the trait | |
732 | /// returns a type of `&T`, but the actual type we assign to the | |
733 | /// *expression* is `T`. So this function just peels off the return | |
734 | /// type by one layer to yield `T`. | |
735 | pub(in super::super) fn make_overloaded_place_return_type( | |
736 | &self, | |
737 | method: MethodCallee<'tcx>, | |
738 | ) -> ty::TypeAndMut<'tcx> { | |
739 | // extract method return type, which will be &T; | |
740 | let ret_ty = method.sig.output(); | |
741 | ||
742 | // method returns &T, but the type as visible to user is T, so deref | |
743 | ret_ty.builtin_deref(true).unwrap() | |
744 | } | |
745 | ||
746 | fn self_type_matches_expected_vid( | |
747 | &self, | |
748 | trait_ref: ty::PolyTraitRef<'tcx>, | |
749 | expected_vid: ty::TyVid, | |
750 | ) -> bool { | |
751 | let self_ty = self.shallow_resolve(trait_ref.skip_binder().self_ty()); | |
752 | debug!( | |
753 | "self_type_matches_expected_vid(trait_ref={:?}, self_ty={:?}, expected_vid={:?})", | |
754 | trait_ref, self_ty, expected_vid | |
755 | ); | |
756 | match *self_ty.kind() { | |
757 | ty::Infer(ty::TyVar(found_vid)) => { | |
758 | // FIXME: consider using `sub_root_var` here so we | |
759 | // can see through subtyping. | |
760 | let found_vid = self.root_var(found_vid); | |
761 | debug!("self_type_matches_expected_vid - found_vid={:?}", found_vid); | |
762 | expected_vid == found_vid | |
763 | } | |
764 | _ => false, | |
765 | } | |
766 | } | |
767 | ||
768 | pub(in super::super) fn obligations_for_self_ty<'b>( | |
769 | &'b self, | |
770 | self_ty: ty::TyVid, | |
771 | ) -> impl Iterator<Item = (ty::PolyTraitRef<'tcx>, traits::PredicateObligation<'tcx>)> | |
772 | + Captures<'tcx> | |
773 | + 'b { | |
774 | // FIXME: consider using `sub_root_var` here so we | |
775 | // can see through subtyping. | |
776 | let ty_var_root = self.root_var(self_ty); | |
777 | debug!( | |
778 | "obligations_for_self_ty: self_ty={:?} ty_var_root={:?} pending_obligations={:?}", | |
779 | self_ty, | |
780 | ty_var_root, | |
781 | self.fulfillment_cx.borrow().pending_obligations() | |
782 | ); | |
783 | ||
784 | self.fulfillment_cx | |
785 | .borrow() | |
786 | .pending_obligations() | |
787 | .into_iter() | |
788 | .filter_map(move |obligation| { | |
5869c6ff | 789 | let bound_predicate = obligation.predicate.kind(); |
fc512014 | 790 | match bound_predicate.skip_binder() { |
6a06907d XL |
791 | ty::PredicateKind::Projection(data) => Some(( |
792 | bound_predicate.rebind(data).required_poly_trait_ref(self.tcx), | |
793 | obligation, | |
794 | )), | |
5869c6ff | 795 | ty::PredicateKind::Trait(data, _) => { |
fc512014 | 796 | Some((bound_predicate.rebind(data).to_poly_trait_ref(), obligation)) |
29967ef6 | 797 | } |
5869c6ff XL |
798 | ty::PredicateKind::Subtype(..) => None, |
799 | ty::PredicateKind::RegionOutlives(..) => None, | |
800 | ty::PredicateKind::TypeOutlives(..) => None, | |
801 | ty::PredicateKind::WellFormed(..) => None, | |
802 | ty::PredicateKind::ObjectSafe(..) => None, | |
803 | ty::PredicateKind::ConstEvaluatable(..) => None, | |
804 | ty::PredicateKind::ConstEquate(..) => None, | |
29967ef6 XL |
805 | // N.B., this predicate is created by breaking down a |
806 | // `ClosureType: FnFoo()` predicate, where | |
807 | // `ClosureType` represents some `Closure`. It can't | |
808 | // possibly be referring to the current closure, | |
809 | // because we haven't produced the `Closure` for | |
810 | // this closure yet; this is exactly why the other | |
811 | // code is looking for a self type of a unresolved | |
812 | // inference variable. | |
5869c6ff XL |
813 | ty::PredicateKind::ClosureKind(..) => None, |
814 | ty::PredicateKind::TypeWellFormedFromEnv(..) => None, | |
29967ef6 XL |
815 | } |
816 | }) | |
817 | .filter(move |(tr, _)| self.self_type_matches_expected_vid(*tr, ty_var_root)) | |
818 | } | |
819 | ||
820 | pub(in super::super) fn type_var_is_sized(&self, self_ty: ty::TyVid) -> bool { | |
821 | self.obligations_for_self_ty(self_ty) | |
822 | .any(|(tr, _)| Some(tr.def_id()) == self.tcx.lang_items().sized_trait()) | |
823 | } | |
824 | ||
825 | pub(in super::super) fn err_args(&self, len: usize) -> Vec<Ty<'tcx>> { | |
826 | vec![self.tcx.ty_error(); len] | |
827 | } | |
828 | ||
829 | /// Unifies the output type with the expected type early, for more coercions | |
830 | /// and forward type information on the input expressions. | |
831 | pub(in super::super) fn expected_inputs_for_expected_output( | |
832 | &self, | |
833 | call_span: Span, | |
834 | expected_ret: Expectation<'tcx>, | |
835 | formal_ret: Ty<'tcx>, | |
836 | formal_args: &[Ty<'tcx>], | |
837 | ) -> Vec<Ty<'tcx>> { | |
838 | let formal_ret = self.resolve_vars_with_obligations(formal_ret); | |
839 | let ret_ty = match expected_ret.only_has_type(self) { | |
840 | Some(ret) => ret, | |
841 | None => return Vec::new(), | |
842 | }; | |
843 | let expect_args = self | |
844 | .fudge_inference_if_ok(|| { | |
845 | // Attempt to apply a subtyping relationship between the formal | |
846 | // return type (likely containing type variables if the function | |
847 | // is polymorphic) and the expected return type. | |
848 | // No argument expectations are produced if unification fails. | |
849 | let origin = self.misc(call_span); | |
850 | let ures = self.at(&origin, self.param_env).sup(ret_ty, &formal_ret); | |
851 | ||
852 | // FIXME(#27336) can't use ? here, Try::from_error doesn't default | |
853 | // to identity so the resulting type is not constrained. | |
854 | match ures { | |
855 | Ok(ok) => { | |
856 | // Process any obligations locally as much as | |
857 | // we can. We don't care if some things turn | |
858 | // out unconstrained or ambiguous, as we're | |
859 | // just trying to get hints here. | |
860 | self.save_and_restore_in_snapshot_flag(|_| { | |
6a06907d | 861 | let mut fulfill = <dyn TraitEngine<'_>>::new(self.tcx); |
29967ef6 XL |
862 | for obligation in ok.obligations { |
863 | fulfill.register_predicate_obligation(self, obligation); | |
864 | } | |
865 | fulfill.select_where_possible(self) | |
866 | }) | |
867 | .map_err(|_| ())?; | |
868 | } | |
869 | Err(_) => return Err(()), | |
870 | } | |
871 | ||
872 | // Record all the argument types, with the substitutions | |
873 | // produced from the above subtyping unification. | |
fc512014 | 874 | Ok(formal_args.iter().map(|&ty| self.resolve_vars_if_possible(ty)).collect()) |
29967ef6 XL |
875 | }) |
876 | .unwrap_or_default(); | |
877 | debug!( | |
878 | "expected_inputs_for_expected_output(formal={:?} -> {:?}, expected={:?} -> {:?})", | |
879 | formal_args, formal_ret, expect_args, expected_ret | |
880 | ); | |
881 | expect_args | |
882 | } | |
883 | ||
884 | pub(in super::super) fn resolve_lang_item_path( | |
885 | &self, | |
886 | lang_item: hir::LangItem, | |
887 | span: Span, | |
888 | hir_id: hir::HirId, | |
889 | ) -> (Res, Ty<'tcx>) { | |
890 | let def_id = self.tcx.require_lang_item(lang_item, Some(span)); | |
891 | let def_kind = self.tcx.def_kind(def_id); | |
892 | ||
893 | let item_ty = if let DefKind::Variant = def_kind { | |
894 | self.tcx.type_of(self.tcx.parent(def_id).expect("variant w/out parent")) | |
895 | } else { | |
896 | self.tcx.type_of(def_id) | |
897 | }; | |
898 | let substs = self.infcx.fresh_substs_for_item(span, def_id); | |
899 | let ty = item_ty.subst(self.tcx, substs); | |
900 | ||
901 | self.write_resolution(hir_id, Ok((def_kind, def_id))); | |
902 | self.add_required_obligations(span, def_id, &substs); | |
903 | (Res::Def(def_kind, def_id), ty) | |
904 | } | |
905 | ||
906 | /// Resolves an associated value path into a base type and associated constant, or method | |
907 | /// resolution. The newly resolved definition is written into `type_dependent_defs`. | |
cdc7bbd5 | 908 | pub fn resolve_ty_and_res_ufcs( |
29967ef6 | 909 | &self, |
cdc7bbd5 | 910 | qpath: &'tcx QPath<'tcx>, |
29967ef6 XL |
911 | hir_id: hir::HirId, |
912 | span: Span, | |
cdc7bbd5 | 913 | ) -> (Res, Option<Ty<'tcx>>, &'tcx [hir::PathSegment<'tcx>]) { |
29967ef6 XL |
914 | debug!("resolve_ty_and_res_ufcs: qpath={:?} hir_id={:?} span={:?}", qpath, hir_id, span); |
915 | let (ty, qself, item_segment) = match *qpath { | |
916 | QPath::Resolved(ref opt_qself, ref path) => { | |
917 | return ( | |
918 | path.res, | |
919 | opt_qself.as_ref().map(|qself| self.to_ty(qself)), | |
6a06907d | 920 | path.segments, |
29967ef6 XL |
921 | ); |
922 | } | |
923 | QPath::TypeRelative(ref qself, ref segment) => (self.to_ty(qself), qself, segment), | |
924 | QPath::LangItem(..) => bug!("`resolve_ty_and_res_ufcs` called on `LangItem`"), | |
925 | }; | |
926 | if let Some(&cached_result) = self.typeck_results.borrow().type_dependent_defs().get(hir_id) | |
927 | { | |
928 | // Return directly on cache hit. This is useful to avoid doubly reporting | |
929 | // errors with default match binding modes. See #44614. | |
5869c6ff | 930 | let def = cached_result.map_or(Res::Err, |(kind, def_id)| Res::Def(kind, def_id)); |
29967ef6 XL |
931 | return (def, Some(ty), slice::from_ref(&**item_segment)); |
932 | } | |
933 | let item_name = item_segment.ident; | |
934 | let result = self.resolve_ufcs(span, item_name, ty, hir_id).or_else(|error| { | |
935 | let result = match error { | |
936 | method::MethodError::PrivateMatch(kind, def_id, _) => Ok((kind, def_id)), | |
937 | _ => Err(ErrorReported), | |
938 | }; | |
5869c6ff | 939 | if item_name.name != kw::Empty { |
29967ef6 XL |
940 | if let Some(mut e) = self.report_method_error( |
941 | span, | |
942 | ty, | |
943 | item_name, | |
944 | SelfSource::QPath(qself), | |
945 | error, | |
946 | None, | |
947 | ) { | |
948 | e.emit(); | |
949 | } | |
950 | } | |
951 | result | |
952 | }); | |
953 | ||
6a06907d XL |
954 | if result.is_ok() { |
955 | self.maybe_lint_bare_trait(qpath, hir_id); | |
956 | } | |
957 | ||
29967ef6 XL |
958 | // Write back the new resolution. |
959 | self.write_resolution(hir_id, result); | |
960 | ( | |
5869c6ff | 961 | result.map_or(Res::Err, |(kind, def_id)| Res::Def(kind, def_id)), |
29967ef6 XL |
962 | Some(ty), |
963 | slice::from_ref(&**item_segment), | |
964 | ) | |
965 | } | |
966 | ||
6a06907d XL |
967 | fn maybe_lint_bare_trait(&self, qpath: &QPath<'_>, hir_id: hir::HirId) { |
968 | if let QPath::TypeRelative(self_ty, _) = qpath { | |
969 | if let TyKind::TraitObject([poly_trait_ref, ..], _, TraitObjectSyntax::None) = | |
970 | self_ty.kind | |
971 | { | |
972 | self.tcx.struct_span_lint_hir(BARE_TRAIT_OBJECTS, hir_id, self_ty.span, |lint| { | |
973 | let mut db = lint | |
974 | .build(&format!("trait objects without an explicit `dyn` are deprecated")); | |
975 | let (sugg, app) = match self.tcx.sess.source_map().span_to_snippet(self_ty.span) | |
976 | { | |
977 | Ok(s) if poly_trait_ref.trait_ref.path.is_global() => { | |
978 | (format!("<dyn ({})>", s), Applicability::MachineApplicable) | |
979 | } | |
980 | Ok(s) => (format!("<dyn {}>", s), Applicability::MachineApplicable), | |
981 | Err(_) => ("<dyn <type>>".to_string(), Applicability::HasPlaceholders), | |
982 | }; | |
983 | db.span_suggestion(self_ty.span, "use `dyn`", sugg, app); | |
984 | db.emit() | |
985 | }); | |
986 | } | |
987 | } | |
988 | } | |
989 | ||
29967ef6 XL |
990 | /// Given a function `Node`, return its `FnDecl` if it exists, or `None` otherwise. |
991 | pub(in super::super) fn get_node_fn_decl( | |
992 | &self, | |
993 | node: Node<'tcx>, | |
994 | ) -> Option<(&'tcx hir::FnDecl<'tcx>, Ident, bool)> { | |
995 | match node { | |
996 | Node::Item(&hir::Item { ident, kind: hir::ItemKind::Fn(ref sig, ..), .. }) => { | |
997 | // This is less than ideal, it will not suggest a return type span on any | |
998 | // method called `main`, regardless of whether it is actually the entry point, | |
999 | // but it will still present it as the reason for the expected type. | |
1000 | Some((&sig.decl, ident, ident.name != sym::main)) | |
1001 | } | |
1002 | Node::TraitItem(&hir::TraitItem { | |
1003 | ident, | |
1004 | kind: hir::TraitItemKind::Fn(ref sig, ..), | |
1005 | .. | |
1006 | }) => Some((&sig.decl, ident, true)), | |
1007 | Node::ImplItem(&hir::ImplItem { | |
1008 | ident, | |
1009 | kind: hir::ImplItemKind::Fn(ref sig, ..), | |
1010 | .. | |
1011 | }) => Some((&sig.decl, ident, false)), | |
1012 | _ => None, | |
1013 | } | |
1014 | } | |
1015 | ||
1016 | /// Given a `HirId`, return the `FnDecl` of the method it is enclosed by and whether a | |
1017 | /// suggestion can be made, `None` otherwise. | |
1018 | pub fn get_fn_decl(&self, blk_id: hir::HirId) -> Option<(&'tcx hir::FnDecl<'tcx>, bool)> { | |
1019 | // Get enclosing Fn, if it is a function or a trait method, unless there's a `loop` or | |
1020 | // `while` before reaching it, as block tail returns are not available in them. | |
1021 | self.tcx.hir().get_return_block(blk_id).and_then(|blk_id| { | |
1022 | let parent = self.tcx.hir().get(blk_id); | |
1023 | self.get_node_fn_decl(parent).map(|(fn_decl, _, is_main)| (fn_decl, is_main)) | |
1024 | }) | |
1025 | } | |
1026 | ||
1027 | pub(in super::super) fn note_internal_mutation_in_method( | |
1028 | &self, | |
1029 | err: &mut DiagnosticBuilder<'_>, | |
1030 | expr: &hir::Expr<'_>, | |
1031 | expected: Ty<'tcx>, | |
1032 | found: Ty<'tcx>, | |
1033 | ) { | |
1034 | if found != self.tcx.types.unit { | |
1035 | return; | |
1036 | } | |
1037 | if let ExprKind::MethodCall(path_segment, _, [rcvr, ..], _) = expr.kind { | |
1038 | if self | |
1039 | .typeck_results | |
1040 | .borrow() | |
1041 | .expr_ty_adjusted_opt(rcvr) | |
1042 | .map_or(true, |ty| expected.peel_refs() != ty.peel_refs()) | |
1043 | { | |
1044 | return; | |
1045 | } | |
1046 | let mut sp = MultiSpan::from_span(path_segment.ident.span); | |
1047 | sp.push_span_label( | |
1048 | path_segment.ident.span, | |
1049 | format!( | |
1050 | "this call modifies {} in-place", | |
1051 | match rcvr.kind { | |
1052 | ExprKind::Path(QPath::Resolved( | |
1053 | None, | |
1054 | hir::Path { segments: [segment], .. }, | |
1055 | )) => format!("`{}`", segment.ident), | |
1056 | _ => "its receiver".to_string(), | |
1057 | } | |
1058 | ), | |
1059 | ); | |
1060 | sp.push_span_label( | |
1061 | rcvr.span, | |
1062 | "you probably want to use this value after calling the method...".to_string(), | |
1063 | ); | |
1064 | err.span_note( | |
1065 | sp, | |
1066 | &format!("method `{}` modifies its receiver in-place", path_segment.ident), | |
1067 | ); | |
1068 | err.note(&format!("...instead of the `()` output of method `{}`", path_segment.ident)); | |
1069 | } | |
1070 | } | |
1071 | ||
1072 | pub(in super::super) fn note_need_for_fn_pointer( | |
1073 | &self, | |
1074 | err: &mut DiagnosticBuilder<'_>, | |
1075 | expected: Ty<'tcx>, | |
1076 | found: Ty<'tcx>, | |
1077 | ) { | |
1078 | let (sig, did, substs) = match (&expected.kind(), &found.kind()) { | |
1079 | (ty::FnDef(did1, substs1), ty::FnDef(did2, substs2)) => { | |
1080 | let sig1 = self.tcx.fn_sig(*did1).subst(self.tcx, substs1); | |
1081 | let sig2 = self.tcx.fn_sig(*did2).subst(self.tcx, substs2); | |
1082 | if sig1 != sig2 { | |
1083 | return; | |
1084 | } | |
1085 | err.note( | |
1086 | "different `fn` items always have unique types, even if their signatures are \ | |
1087 | the same", | |
1088 | ); | |
1089 | (sig1, *did1, substs1) | |
1090 | } | |
1091 | (ty::FnDef(did, substs), ty::FnPtr(sig2)) => { | |
1092 | let sig1 = self.tcx.fn_sig(*did).subst(self.tcx, substs); | |
1093 | if sig1 != *sig2 { | |
1094 | return; | |
1095 | } | |
1096 | (sig1, *did, substs) | |
1097 | } | |
1098 | _ => return, | |
1099 | }; | |
1100 | err.help(&format!("change the expected type to be function pointer `{}`", sig)); | |
1101 | err.help(&format!( | |
1102 | "if the expected type is due to type inference, cast the expected `fn` to a function \ | |
1103 | pointer: `{} as {}`", | |
1104 | self.tcx.def_path_str_with_substs(did, substs), | |
1105 | sig | |
1106 | )); | |
1107 | } | |
1108 | ||
1109 | pub(in super::super) fn could_remove_semicolon( | |
1110 | &self, | |
1111 | blk: &'tcx hir::Block<'tcx>, | |
1112 | expected_ty: Ty<'tcx>, | |
1113 | ) -> Option<(Span, StatementAsExpression)> { | |
1114 | // Be helpful when the user wrote `{... expr;}` and | |
1115 | // taking the `;` off is enough to fix the error. | |
1116 | let last_stmt = blk.stmts.last()?; | |
1117 | let last_expr = match last_stmt.kind { | |
1118 | hir::StmtKind::Semi(ref e) => e, | |
1119 | _ => return None, | |
1120 | }; | |
1121 | let last_expr_ty = self.node_ty(last_expr.hir_id); | |
1122 | let needs_box = match (last_expr_ty.kind(), expected_ty.kind()) { | |
6a06907d XL |
1123 | (ty::Opaque(last_def_id, _), ty::Opaque(exp_def_id, _)) |
1124 | if last_def_id == exp_def_id => | |
1125 | { | |
1126 | StatementAsExpression::CorrectType | |
1127 | } | |
29967ef6 XL |
1128 | (ty::Opaque(last_def_id, last_bounds), ty::Opaque(exp_def_id, exp_bounds)) => { |
1129 | debug!( | |
1130 | "both opaque, likely future {:?} {:?} {:?} {:?}", | |
1131 | last_def_id, last_bounds, exp_def_id, exp_bounds | |
1132 | ); | |
6a06907d XL |
1133 | |
1134 | let (last_local_id, exp_local_id) = | |
1135 | match (last_def_id.as_local(), exp_def_id.as_local()) { | |
1136 | (Some(last_hir_id), Some(exp_hir_id)) => (last_hir_id, exp_hir_id), | |
1137 | (_, _) => return None, | |
1138 | }; | |
1139 | ||
1140 | let last_hir_id = self.tcx.hir().local_def_id_to_hir_id(last_local_id); | |
1141 | let exp_hir_id = self.tcx.hir().local_def_id_to_hir_id(exp_local_id); | |
1142 | ||
29967ef6 XL |
1143 | match ( |
1144 | &self.tcx.hir().expect_item(last_hir_id).kind, | |
1145 | &self.tcx.hir().expect_item(exp_hir_id).kind, | |
1146 | ) { | |
1147 | ( | |
1148 | hir::ItemKind::OpaqueTy(hir::OpaqueTy { bounds: last_bounds, .. }), | |
1149 | hir::ItemKind::OpaqueTy(hir::OpaqueTy { bounds: exp_bounds, .. }), | |
cdc7bbd5 | 1150 | ) if iter::zip(*last_bounds, *exp_bounds).all(|(left, right)| { |
29967ef6 XL |
1151 | match (left, right) { |
1152 | ( | |
1153 | hir::GenericBound::Trait(tl, ml), | |
1154 | hir::GenericBound::Trait(tr, mr), | |
1155 | ) if tl.trait_ref.trait_def_id() == tr.trait_ref.trait_def_id() | |
1156 | && ml == mr => | |
1157 | { | |
1158 | true | |
1159 | } | |
1160 | ( | |
1161 | hir::GenericBound::LangItemTrait(langl, _, _, argsl), | |
1162 | hir::GenericBound::LangItemTrait(langr, _, _, argsr), | |
1163 | ) if langl == langr => { | |
1164 | // FIXME: consider the bounds! | |
1165 | debug!("{:?} {:?}", argsl, argsr); | |
1166 | true | |
1167 | } | |
1168 | _ => false, | |
1169 | } | |
1170 | }) => | |
1171 | { | |
1172 | StatementAsExpression::NeedsBoxing | |
1173 | } | |
1174 | _ => StatementAsExpression::CorrectType, | |
1175 | } | |
1176 | } | |
1177 | _ => StatementAsExpression::CorrectType, | |
1178 | }; | |
1179 | if (matches!(last_expr_ty.kind(), ty::Error(_)) | |
1180 | || self.can_sub(self.param_env, last_expr_ty, expected_ty).is_err()) | |
1181 | && matches!(needs_box, StatementAsExpression::CorrectType) | |
1182 | { | |
1183 | return None; | |
1184 | } | |
1185 | let original_span = original_sp(last_stmt.span, blk.span); | |
1186 | Some((original_span.with_lo(original_span.hi() - BytePos(1)), needs_box)) | |
1187 | } | |
1188 | ||
1189 | // Instantiates the given path, which must refer to an item with the given | |
1190 | // number of type parameters and type. | |
1191 | pub fn instantiate_value_path( | |
1192 | &self, | |
1193 | segments: &[hir::PathSegment<'_>], | |
1194 | self_ty: Option<Ty<'tcx>>, | |
1195 | res: Res, | |
1196 | span: Span, | |
1197 | hir_id: hir::HirId, | |
1198 | ) -> (Ty<'tcx>, Res) { | |
1199 | debug!( | |
1200 | "instantiate_value_path(segments={:?}, self_ty={:?}, res={:?}, hir_id={})", | |
1201 | segments, self_ty, res, hir_id, | |
1202 | ); | |
1203 | ||
1204 | let tcx = self.tcx; | |
1205 | ||
1206 | let path_segs = match res { | |
1207 | Res::Local(_) | Res::SelfCtor(_) => vec![], | |
6a06907d XL |
1208 | Res::Def(kind, def_id) => <dyn AstConv<'_>>::def_ids_for_value_path_segments( |
1209 | self, segments, self_ty, kind, def_id, | |
1210 | ), | |
29967ef6 XL |
1211 | _ => bug!("instantiate_value_path on {:?}", res), |
1212 | }; | |
1213 | ||
1214 | let mut user_self_ty = None; | |
1215 | let mut is_alias_variant_ctor = false; | |
1216 | match res { | |
1217 | Res::Def(DefKind::Ctor(CtorOf::Variant, _), _) => { | |
1218 | if let Some(self_ty) = self_ty { | |
1219 | let adt_def = self_ty.ty_adt_def().unwrap(); | |
1220 | user_self_ty = Some(UserSelfTy { impl_def_id: adt_def.did, self_ty }); | |
1221 | is_alias_variant_ctor = true; | |
1222 | } | |
1223 | } | |
1224 | Res::Def(DefKind::AssocFn | DefKind::AssocConst, def_id) => { | |
1225 | let container = tcx.associated_item(def_id).container; | |
1226 | debug!("instantiate_value_path: def_id={:?} container={:?}", def_id, container); | |
1227 | match container { | |
1228 | ty::TraitContainer(trait_did) => { | |
5869c6ff | 1229 | callee::check_legal_trait_for_method_call(tcx, span, None, span, trait_did) |
29967ef6 XL |
1230 | } |
1231 | ty::ImplContainer(impl_def_id) => { | |
1232 | if segments.len() == 1 { | |
1233 | // `<T>::assoc` will end up here, and so | |
1234 | // can `T::assoc`. It this came from an | |
1235 | // inherent impl, we need to record the | |
1236 | // `T` for posterity (see `UserSelfTy` for | |
1237 | // details). | |
1238 | let self_ty = self_ty.expect("UFCS sugared assoc missing Self"); | |
1239 | user_self_ty = Some(UserSelfTy { impl_def_id, self_ty }); | |
1240 | } | |
1241 | } | |
1242 | } | |
1243 | } | |
1244 | _ => {} | |
1245 | } | |
1246 | ||
1247 | // Now that we have categorized what space the parameters for each | |
1248 | // segment belong to, let's sort out the parameters that the user | |
1249 | // provided (if any) into their appropriate spaces. We'll also report | |
1250 | // errors if type parameters are provided in an inappropriate place. | |
1251 | ||
1252 | let generic_segs: FxHashSet<_> = path_segs.iter().map(|PathSeg(_, index)| index).collect(); | |
6a06907d | 1253 | let generics_has_err = <dyn AstConv<'_>>::prohibit_generics( |
29967ef6 XL |
1254 | self, |
1255 | segments.iter().enumerate().filter_map(|(index, seg)| { | |
1256 | if !generic_segs.contains(&index) || is_alias_variant_ctor { | |
1257 | Some(seg) | |
1258 | } else { | |
1259 | None | |
1260 | } | |
1261 | }), | |
1262 | ); | |
1263 | ||
1264 | if let Res::Local(hid) = res { | |
1265 | let ty = self.local_ty(span, hid).decl_ty; | |
fc512014 | 1266 | let ty = self.normalize_associated_types_in(span, ty); |
29967ef6 XL |
1267 | self.write_ty(hir_id, ty); |
1268 | return (ty, res); | |
1269 | } | |
1270 | ||
1271 | if generics_has_err { | |
1272 | // Don't try to infer type parameters when prohibited generic arguments were given. | |
1273 | user_self_ty = None; | |
1274 | } | |
1275 | ||
1276 | // Now we have to compare the types that the user *actually* | |
1277 | // provided against the types that were *expected*. If the user | |
1278 | // did not provide any types, then we want to substitute inference | |
1279 | // variables. If the user provided some types, we may still need | |
1280 | // to add defaults. If the user provided *too many* types, that's | |
1281 | // a problem. | |
1282 | ||
1283 | let mut infer_args_for_err = FxHashSet::default(); | |
5869c6ff | 1284 | |
29967ef6 XL |
1285 | for &PathSeg(def_id, index) in &path_segs { |
1286 | let seg = &segments[index]; | |
1287 | let generics = tcx.generics_of(def_id); | |
5869c6ff | 1288 | |
29967ef6 XL |
1289 | // Argument-position `impl Trait` is treated as a normal generic |
1290 | // parameter internally, but we don't allow users to specify the | |
1291 | // parameter's value explicitly, so we have to do some error- | |
1292 | // checking here. | |
1293 | if let GenericArgCountResult { | |
5869c6ff | 1294 | correct: Err(GenericArgCountMismatch { reported: Some(_), .. }), |
29967ef6 | 1295 | .. |
6a06907d | 1296 | } = <dyn AstConv<'_>>::check_generic_arg_count_for_call( |
5869c6ff XL |
1297 | tcx, |
1298 | span, | |
1299 | def_id, | |
1300 | &generics, | |
1301 | seg, | |
1302 | IsMethodCall::No, | |
29967ef6 XL |
1303 | ) { |
1304 | infer_args_for_err.insert(index); | |
1305 | self.set_tainted_by_errors(); // See issue #53251. | |
1306 | } | |
1307 | } | |
1308 | ||
1309 | let has_self = path_segs | |
1310 | .last() | |
1311 | .map(|PathSeg(def_id, _)| tcx.generics_of(*def_id).has_self) | |
1312 | .unwrap_or(false); | |
1313 | ||
1314 | let (res, self_ctor_substs) = if let Res::SelfCtor(impl_def_id) = res { | |
1315 | let ty = self.normalize_ty(span, tcx.at(span).type_of(impl_def_id)); | |
1316 | match *ty.kind() { | |
1317 | ty::Adt(adt_def, substs) if adt_def.has_ctor() => { | |
1318 | let variant = adt_def.non_enum_variant(); | |
1319 | let ctor_def_id = variant.ctor_def_id.unwrap(); | |
1320 | ( | |
1321 | Res::Def(DefKind::Ctor(CtorOf::Struct, variant.ctor_kind), ctor_def_id), | |
1322 | Some(substs), | |
1323 | ) | |
1324 | } | |
1325 | _ => { | |
1326 | let mut err = tcx.sess.struct_span_err( | |
1327 | span, | |
1328 | "the `Self` constructor can only be used with tuple or unit structs", | |
1329 | ); | |
1330 | if let Some(adt_def) = ty.ty_adt_def() { | |
1331 | match adt_def.adt_kind() { | |
1332 | AdtKind::Enum => { | |
1333 | err.help("did you mean to use one of the enum's variants?"); | |
1334 | } | |
1335 | AdtKind::Struct | AdtKind::Union => { | |
1336 | err.span_suggestion( | |
1337 | span, | |
1338 | "use curly brackets", | |
1339 | String::from("Self { /* fields */ }"), | |
1340 | Applicability::HasPlaceholders, | |
1341 | ); | |
1342 | } | |
1343 | } | |
1344 | } | |
1345 | err.emit(); | |
1346 | ||
1347 | return (tcx.ty_error(), res); | |
1348 | } | |
1349 | } | |
1350 | } else { | |
1351 | (res, None) | |
1352 | }; | |
1353 | let def_id = res.def_id(); | |
1354 | ||
1355 | // The things we are substituting into the type should not contain | |
1356 | // escaping late-bound regions, and nor should the base type scheme. | |
1357 | let ty = tcx.type_of(def_id); | |
1358 | ||
1359 | let arg_count = GenericArgCountResult { | |
1360 | explicit_late_bound: ExplicitLateBound::No, | |
1361 | correct: if infer_args_for_err.is_empty() { | |
1362 | Ok(()) | |
1363 | } else { | |
1364 | Err(GenericArgCountMismatch::default()) | |
1365 | }, | |
1366 | }; | |
1367 | ||
fc512014 XL |
1368 | struct CreateCtorSubstsContext<'a, 'tcx> { |
1369 | fcx: &'a FnCtxt<'a, 'tcx>, | |
1370 | span: Span, | |
1371 | path_segs: &'a [PathSeg], | |
1372 | infer_args_for_err: &'a FxHashSet<usize>, | |
1373 | segments: &'a [hir::PathSegment<'a>], | |
1374 | } | |
1375 | impl<'tcx, 'a> CreateSubstsForGenericArgsCtxt<'a, 'tcx> for CreateCtorSubstsContext<'a, 'tcx> { | |
1376 | fn args_for_def_id( | |
1377 | &mut self, | |
1378 | def_id: DefId, | |
1379 | ) -> (Option<&'a hir::GenericArgs<'a>>, bool) { | |
1380 | if let Some(&PathSeg(_, index)) = | |
1381 | self.path_segs.iter().find(|&PathSeg(did, _)| *did == def_id) | |
1382 | { | |
1383 | // If we've encountered an `impl Trait`-related error, we're just | |
1384 | // going to infer the arguments for better error messages. | |
1385 | if !self.infer_args_for_err.contains(&index) { | |
1386 | // Check whether the user has provided generic arguments. | |
1387 | if let Some(ref data) = self.segments[index].args { | |
1388 | return (Some(data), self.segments[index].infer_args); | |
29967ef6 | 1389 | } |
29967ef6 | 1390 | } |
fc512014 XL |
1391 | return (None, self.segments[index].infer_args); |
1392 | } | |
29967ef6 | 1393 | |
fc512014 XL |
1394 | (None, true) |
1395 | } | |
1396 | ||
1397 | fn provided_kind( | |
1398 | &mut self, | |
1399 | param: &ty::GenericParamDef, | |
1400 | arg: &GenericArg<'_>, | |
1401 | ) -> subst::GenericArg<'tcx> { | |
1402 | match (¶m.kind, arg) { | |
29967ef6 | 1403 | (GenericParamDefKind::Lifetime, GenericArg::Lifetime(lt)) => { |
6a06907d | 1404 | <dyn AstConv<'_>>::ast_region_to_region(self.fcx, lt, Some(param)).into() |
29967ef6 XL |
1405 | } |
1406 | (GenericParamDefKind::Type { .. }, GenericArg::Type(ty)) => { | |
fc512014 | 1407 | self.fcx.to_ty(ty).into() |
29967ef6 | 1408 | } |
cdc7bbd5 | 1409 | (GenericParamDefKind::Const { .. }, GenericArg::Const(ct)) => { |
fc512014 | 1410 | self.fcx.const_arg_to_const(&ct.value, param.def_id).into() |
29967ef6 XL |
1411 | } |
1412 | _ => unreachable!(), | |
fc512014 XL |
1413 | } |
1414 | } | |
1415 | ||
1416 | fn inferred_kind( | |
1417 | &mut self, | |
1418 | substs: Option<&[subst::GenericArg<'tcx>]>, | |
1419 | param: &ty::GenericParamDef, | |
1420 | infer_args: bool, | |
1421 | ) -> subst::GenericArg<'tcx> { | |
1422 | let tcx = self.fcx.tcx(); | |
1423 | match param.kind { | |
1424 | GenericParamDefKind::Lifetime => { | |
1425 | self.fcx.re_infer(Some(param), self.span).unwrap().into() | |
1426 | } | |
1427 | GenericParamDefKind::Type { has_default, .. } => { | |
1428 | if !infer_args && has_default { | |
1429 | // If we have a default, then we it doesn't matter that we're not | |
1430 | // inferring the type arguments: we provide the default where any | |
1431 | // is missing. | |
1432 | let default = tcx.type_of(param.def_id); | |
1433 | self.fcx | |
1434 | .normalize_ty( | |
1435 | self.span, | |
1436 | default.subst_spanned(tcx, substs.unwrap(), Some(self.span)), | |
29967ef6 XL |
1437 | ) |
1438 | .into() | |
fc512014 XL |
1439 | } else { |
1440 | // If no type arguments were provided, we have to infer them. | |
1441 | // This case also occurs as a result of some malformed input, e.g. | |
1442 | // a lifetime argument being given instead of a type parameter. | |
1443 | // Using inference instead of `Error` gives better error messages. | |
1444 | self.fcx.var_for_def(self.span, param) | |
29967ef6 XL |
1445 | } |
1446 | } | |
cdc7bbd5 XL |
1447 | GenericParamDefKind::Const { has_default, .. } => { |
1448 | if !infer_args && has_default { | |
1449 | tcx.const_param_default(param.def_id) | |
1450 | .subst_spanned(tcx, substs.unwrap(), Some(self.span)) | |
1451 | .into() | |
1452 | } else { | |
1453 | self.fcx.var_for_def(self.span, param) | |
1454 | } | |
fc512014 XL |
1455 | } |
1456 | } | |
1457 | } | |
1458 | } | |
1459 | ||
1460 | let substs = self_ctor_substs.unwrap_or_else(|| { | |
6a06907d | 1461 | <dyn AstConv<'_>>::create_substs_for_generic_args( |
fc512014 XL |
1462 | tcx, |
1463 | def_id, | |
1464 | &[][..], | |
1465 | has_self, | |
1466 | self_ty, | |
cdc7bbd5 | 1467 | &arg_count, |
fc512014 XL |
1468 | &mut CreateCtorSubstsContext { |
1469 | fcx: self, | |
1470 | span, | |
1471 | path_segs: &path_segs, | |
1472 | infer_args_for_err: &infer_args_for_err, | |
1473 | segments, | |
29967ef6 XL |
1474 | }, |
1475 | ) | |
1476 | }); | |
1477 | assert!(!substs.has_escaping_bound_vars()); | |
1478 | assert!(!ty.has_escaping_bound_vars()); | |
1479 | ||
1480 | // First, store the "user substs" for later. | |
1481 | self.write_user_type_annotation_from_substs(hir_id, def_id, substs, user_self_ty); | |
1482 | ||
1483 | self.add_required_obligations(span, def_id, &substs); | |
1484 | ||
1485 | // Substitute the values for the type parameters into the type of | |
1486 | // the referenced item. | |
fc512014 | 1487 | let ty_substituted = self.instantiate_type_scheme(span, &substs, ty); |
29967ef6 XL |
1488 | |
1489 | if let Some(UserSelfTy { impl_def_id, self_ty }) = user_self_ty { | |
1490 | // In the case of `Foo<T>::method` and `<Foo<T>>::method`, if `method` | |
1491 | // is inherent, there is no `Self` parameter; instead, the impl needs | |
1492 | // type parameters, which we can infer by unifying the provided `Self` | |
1493 | // with the substituted impl type. | |
1494 | // This also occurs for an enum variant on a type alias. | |
1495 | let ty = tcx.type_of(impl_def_id); | |
1496 | ||
fc512014 | 1497 | let impl_ty = self.instantiate_type_scheme(span, &substs, ty); |
29967ef6 XL |
1498 | match self.at(&self.misc(span), self.param_env).sup(impl_ty, self_ty) { |
1499 | Ok(ok) => self.register_infer_ok_obligations(ok), | |
1500 | Err(_) => { | |
1501 | self.tcx.sess.delay_span_bug( | |
1502 | span, | |
1503 | &format!( | |
1504 | "instantiate_value_path: (UFCS) {:?} was a subtype of {:?} but now is not?", | |
1505 | self_ty, | |
1506 | impl_ty, | |
1507 | ), | |
1508 | ); | |
1509 | } | |
1510 | } | |
1511 | } | |
1512 | ||
1513 | self.check_rustc_args_require_const(def_id, hir_id, span); | |
1514 | ||
1515 | debug!("instantiate_value_path: type of {:?} is {:?}", hir_id, ty_substituted); | |
1516 | self.write_substs(hir_id, substs); | |
1517 | ||
1518 | (ty_substituted, res) | |
1519 | } | |
1520 | ||
1521 | /// Add all the obligations that are required, substituting and normalized appropriately. | |
1522 | fn add_required_obligations(&self, span: Span, def_id: DefId, substs: &SubstsRef<'tcx>) { | |
1523 | let (bounds, spans) = self.instantiate_bounds(span, def_id, &substs); | |
1524 | ||
1525 | for (i, mut obligation) in traits::predicates_for_generics( | |
1526 | traits::ObligationCause::new(span, self.body_id, traits::ItemObligation(def_id)), | |
1527 | self.param_env, | |
1528 | bounds, | |
1529 | ) | |
1530 | .enumerate() | |
1531 | { | |
1532 | // This makes the error point at the bound, but we want to point at the argument | |
1533 | if let Some(span) = spans.get(i) { | |
1534 | obligation.cause.make_mut().code = traits::BindingObligation(def_id, *span); | |
1535 | } | |
1536 | self.register_predicate(obligation); | |
1537 | } | |
1538 | } | |
1539 | ||
1540 | /// Resolves `typ` by a single level if `typ` is a type variable. | |
1541 | /// If no resolution is possible, then an error is reported. | |
1542 | /// Numeric inference variables may be left unresolved. | |
1543 | pub fn structurally_resolved_type(&self, sp: Span, ty: Ty<'tcx>) -> Ty<'tcx> { | |
1544 | let ty = self.resolve_vars_with_obligations(ty); | |
1545 | if !ty.is_ty_var() { | |
1546 | ty | |
1547 | } else { | |
1548 | if !self.is_tainted_by_errors() { | |
5869c6ff | 1549 | self.emit_inference_failure_err((**self).body_id, sp, ty.into(), vec![], E0282) |
29967ef6 XL |
1550 | .note("type must be known at this point") |
1551 | .emit(); | |
1552 | } | |
1553 | let err = self.tcx.ty_error(); | |
1554 | self.demand_suptype(sp, err, ty); | |
1555 | err | |
1556 | } | |
1557 | } | |
1558 | ||
1559 | pub(in super::super) fn with_breakable_ctxt<F: FnOnce() -> R, R>( | |
1560 | &self, | |
1561 | id: hir::HirId, | |
1562 | ctxt: BreakableCtxt<'tcx>, | |
1563 | f: F, | |
1564 | ) -> (BreakableCtxt<'tcx>, R) { | |
1565 | let index; | |
1566 | { | |
1567 | let mut enclosing_breakables = self.enclosing_breakables.borrow_mut(); | |
1568 | index = enclosing_breakables.stack.len(); | |
1569 | enclosing_breakables.by_id.insert(id, index); | |
1570 | enclosing_breakables.stack.push(ctxt); | |
1571 | } | |
1572 | let result = f(); | |
1573 | let ctxt = { | |
1574 | let mut enclosing_breakables = self.enclosing_breakables.borrow_mut(); | |
1575 | debug_assert!(enclosing_breakables.stack.len() == index + 1); | |
1576 | enclosing_breakables.by_id.remove(&id).expect("missing breakable context"); | |
1577 | enclosing_breakables.stack.pop().expect("missing breakable context") | |
1578 | }; | |
1579 | (ctxt, result) | |
1580 | } | |
1581 | ||
1582 | /// Instantiate a QueryResponse in a probe context, without a | |
1583 | /// good ObligationCause. | |
1584 | pub(in super::super) fn probe_instantiate_query_response( | |
1585 | &self, | |
1586 | span: Span, | |
1587 | original_values: &OriginalQueryValues<'tcx>, | |
1588 | query_result: &Canonical<'tcx, QueryResponse<'tcx, Ty<'tcx>>>, | |
1589 | ) -> InferResult<'tcx, Ty<'tcx>> { | |
1590 | self.instantiate_query_response_and_region_obligations( | |
1591 | &traits::ObligationCause::misc(span, self.body_id), | |
1592 | self.param_env, | |
1593 | original_values, | |
1594 | query_result, | |
1595 | ) | |
1596 | } | |
1597 | ||
1598 | /// Returns `true` if an expression is contained inside the LHS of an assignment expression. | |
1599 | pub(in super::super) fn expr_in_place(&self, mut expr_id: hir::HirId) -> bool { | |
1600 | let mut contained_in_place = false; | |
1601 | ||
1602 | while let hir::Node::Expr(parent_expr) = | |
1603 | self.tcx.hir().get(self.tcx.hir().get_parent_node(expr_id)) | |
1604 | { | |
1605 | match &parent_expr.kind { | |
1606 | hir::ExprKind::Assign(lhs, ..) | hir::ExprKind::AssignOp(_, lhs, ..) => { | |
1607 | if lhs.hir_id == expr_id { | |
1608 | contained_in_place = true; | |
1609 | break; | |
1610 | } | |
1611 | } | |
1612 | _ => (), | |
1613 | } | |
1614 | expr_id = parent_expr.hir_id; | |
1615 | } | |
1616 | ||
1617 | contained_in_place | |
1618 | } | |
1619 | } |