1 use crate::callee::{self, DeferredCallResolution};
2 use crate::method::{self, MethodCallee, SelfSource};
3 use crate::rvalue_scopes;
4 use crate::{BreakableCtxt, Diverges, Expectation, FnCtxt, LocalTy};
5 use rustc_data_structures::captures::Captures;
6 use rustc_data_structures::fx::FxHashSet;
7 use rustc_errors::{Applicability, Diagnostic, ErrorGuaranteed, MultiSpan};
9 use rustc_hir::def::{CtorOf, DefKind, Res};
10 use rustc_hir::def_id::DefId;
11 use rustc_hir::lang_items::LangItem;
12 use rustc_hir::{ExprKind, GenericArg, Node, QPath};
13 use rustc_hir_analysis::astconv::{
14 AstConv, CreateSubstsForGenericArgsCtxt, ExplicitLateBound, GenericArgCountMismatch,
15 GenericArgCountResult, IsMethodCall, PathSeg,
17 use rustc_infer::infer::canonical::{Canonical, OriginalQueryValues, QueryResponse};
18 use rustc_infer::infer::error_reporting::TypeAnnotationNeeded::E0282;
19 use rustc_infer::infer::{InferOk, InferResult};
20 use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow, AutoBorrowMutability};
21 use rustc_middle::ty::error::TypeError;
22 use rustc_middle::ty::fold::TypeFoldable;
23 use rustc_middle::ty::visit::TypeVisitable;
24 use rustc_middle::ty::{
25 self, AdtKind, CanonicalUserType, DefIdTree, EarlyBinder, GenericParamDefKind, Ty, UserType,
27 use rustc_middle::ty::{GenericArgKind, InternalSubsts, SubstsRef, UserSelfTy, UserSubsts};
28 use rustc_session::lint;
29 use rustc_span::def_id::LocalDefId;
30 use rustc_span::hygiene::DesugaringKind;
31 use rustc_span::symbol::{kw, sym, Ident};
32 use rustc_span::{Span, DUMMY_SP};
33 use rustc_trait_selection::infer::InferCtxtExt as _;
34 use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt as _;
35 use rustc_trait_selection::traits::{self, ObligationCause, ObligationCauseCode, ObligationCtxt};
37 use std::collections::hash_map::Entry;
40 impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
41 /// Produces warning on the given node, if the current point in the
42 /// function is unreachable, and there hasn't been another warning.
43 pub(in super::super) fn warn_if_unreachable(&self, id: hir::HirId, span: Span, kind: &str) {
44 // FIXME: Combine these two 'if' expressions into one once
45 // let chains are implemented
46 if let Diverges::Always { span: orig_span, custom_note } = self.diverges.get() {
47 // If span arose from a desugaring of `if` or `while`, then it is the condition itself,
48 // which diverges, that we are about to lint on. This gives suboptimal diagnostics.
49 // Instead, stop here so that the `if`- or `while`-expression's block is linted instead.
50 if !span.is_desugaring(DesugaringKind::CondTemporary)
51 && !span.is_desugaring(DesugaringKind::Async)
52 && !orig_span.is_desugaring(DesugaringKind::Await)
54 self.diverges.set(Diverges::WarnedAlways);
56 debug!("warn_if_unreachable: id={:?} span={:?} kind={}", id, span, kind);
58 let msg = format!("unreachable {}", kind);
59 self.tcx().struct_span_lint_hir(
60 lint::builtin::UNREACHABLE_CODE,
65 lint.span_label(span, &msg).span_label(
68 .unwrap_or("any code following this expression is unreachable"),
76 /// Resolves type and const variables in `ty` if possible. Unlike the infcx
77 /// version (resolve_vars_if_possible), this version will
78 /// also select obligations if it seems useful, in an effort
79 /// to get more type information.
80 pub(in super::super) fn resolve_vars_with_obligations(&self, ty: Ty<'tcx>) -> Ty<'tcx> {
81 self.resolve_vars_with_obligations_and_mutate_fulfillment(ty, |_| {})
84 #[instrument(skip(self, mutate_fulfillment_errors), level = "debug", ret)]
85 pub(in super::super) fn resolve_vars_with_obligations_and_mutate_fulfillment(
88 mutate_fulfillment_errors: impl Fn(&mut Vec<traits::FulfillmentError<'tcx>>),
90 // No Infer()? Nothing needs doing.
91 if !ty.has_non_region_infer() {
92 debug!("no inference var, nothing needs doing");
96 // If `ty` is a type variable, see whether we already know what it is.
97 ty = self.resolve_vars_if_possible(ty);
98 if !ty.has_non_region_infer() {
103 // If not, try resolving pending obligations as much as
104 // possible. This can help substantially when there are
105 // indirect dependencies that don't seem worth tracking
107 self.select_obligations_where_possible(mutate_fulfillment_errors);
108 self.resolve_vars_if_possible(ty)
111 pub(in super::super) fn record_deferred_call_resolution(
113 closure_def_id: LocalDefId,
114 r: DeferredCallResolution<'tcx>,
116 let mut deferred_call_resolutions = self.deferred_call_resolutions.borrow_mut();
117 deferred_call_resolutions.entry(closure_def_id).or_default().push(r);
120 pub(in super::super) fn remove_deferred_call_resolutions(
122 closure_def_id: LocalDefId,
123 ) -> Vec<DeferredCallResolution<'tcx>> {
124 let mut deferred_call_resolutions = self.deferred_call_resolutions.borrow_mut();
125 deferred_call_resolutions.remove(&closure_def_id).unwrap_or_default()
128 pub fn tag(&self) -> String {
129 format!("{:p}", self)
132 pub fn local_ty(&self, span: Span, nid: hir::HirId) -> LocalTy<'tcx> {
133 self.locals.borrow().get(&nid).cloned().unwrap_or_else(|| {
134 span_bug!(span, "no type for local variable {}", self.tcx.hir().node_to_string(nid))
139 pub fn write_ty(&self, id: hir::HirId, ty: Ty<'tcx>) {
140 debug!("write_ty({:?}, {:?}) in fcx {}", id, self.resolve_vars_if_possible(ty), self.tag());
141 self.typeck_results.borrow_mut().node_types_mut().insert(id, ty);
143 if let Err(e) = ty.error_reported() {
144 self.set_tainted_by_errors(e);
148 pub fn write_field_index(&self, hir_id: hir::HirId, index: usize) {
149 self.typeck_results.borrow_mut().field_indices_mut().insert(hir_id, index);
152 #[instrument(level = "debug", skip(self))]
153 pub(in super::super) fn write_resolution(
156 r: Result<(DefKind, DefId), ErrorGuaranteed>,
158 self.typeck_results.borrow_mut().type_dependent_defs_mut().insert(hir_id, r);
161 #[instrument(level = "debug", skip(self))]
162 pub fn write_method_call(&self, hir_id: hir::HirId, method: MethodCallee<'tcx>) {
163 self.write_resolution(hir_id, Ok((DefKind::AssocFn, method.def_id)));
164 self.write_substs(hir_id, method.substs);
166 // When the method is confirmed, the `method.substs` includes
167 // parameters from not just the method, but also the impl of
168 // the method -- in particular, the `Self` type will be fully
169 // resolved. However, those are not something that the "user
170 // specified" -- i.e., those types come from the inferred type
171 // of the receiver, not something the user wrote. So when we
172 // create the user-substs, we want to replace those earlier
173 // types with just the types that the user actually wrote --
174 // that is, those that appear on the *method itself*.
176 // As an example, if the user wrote something like
177 // `foo.bar::<u32>(...)` -- the `Self` type here will be the
178 // type of `foo` (possibly adjusted), but we don't want to
179 // include that. We want just the `[_, u32]` part.
180 if !method.substs.is_empty() {
181 let method_generics = self.tcx.generics_of(method.def_id);
182 if !method_generics.params.is_empty() {
183 let user_type_annotation = self.probe(|_| {
184 let user_substs = UserSubsts {
185 substs: InternalSubsts::for_item(self.tcx, method.def_id, |param, _| {
186 let i = param.index as usize;
187 if i < method_generics.parent_count {
188 self.var_for_def(DUMMY_SP, param)
193 user_self_ty: None, // not relevant here
196 self.canonicalize_user_type_annotation(UserType::TypeOf(
202 debug!("write_method_call: user_type_annotation={:?}", user_type_annotation);
203 self.write_user_type_annotation(hir_id, user_type_annotation);
208 pub fn write_substs(&self, node_id: hir::HirId, substs: SubstsRef<'tcx>) {
209 if !substs.is_empty() {
210 debug!("write_substs({:?}, {:?}) in fcx {}", node_id, substs, self.tag());
212 self.typeck_results.borrow_mut().node_substs_mut().insert(node_id, substs);
216 /// Given the substs that we just converted from the HIR, try to
217 /// canonicalize them and store them as user-given substitutions
218 /// (i.e., substitutions that must be respected by the NLL check).
220 /// This should be invoked **before any unifications have
221 /// occurred**, so that annotations like `Vec<_>` are preserved
223 #[instrument(skip(self), level = "debug")]
224 pub fn write_user_type_annotation_from_substs(
228 substs: SubstsRef<'tcx>,
229 user_self_ty: Option<UserSelfTy<'tcx>>,
231 debug!("fcx {}", self.tag());
233 if Self::can_contain_user_lifetime_bounds((substs, user_self_ty)) {
234 let canonicalized = self.canonicalize_user_type_annotation(UserType::TypeOf(
236 UserSubsts { substs, user_self_ty },
238 debug!(?canonicalized);
239 self.write_user_type_annotation(hir_id, canonicalized);
243 #[instrument(skip(self), level = "debug")]
244 pub fn write_user_type_annotation(
247 canonical_user_type_annotation: CanonicalUserType<'tcx>,
249 debug!("fcx {}", self.tag());
251 if !canonical_user_type_annotation.is_identity() {
254 .user_provided_types_mut()
255 .insert(hir_id, canonical_user_type_annotation);
257 debug!("skipping identity substs");
261 #[instrument(skip(self, expr), level = "debug")]
262 pub fn apply_adjustments(&self, expr: &hir::Expr<'_>, adj: Vec<Adjustment<'tcx>>) {
263 debug!("expr = {:#?}", expr);
270 if let Adjust::NeverToAny = a.kind {
271 if a.target.is_ty_var() {
272 self.diverging_type_vars.borrow_mut().insert(a.target);
273 debug!("apply_adjustments: adding `{:?}` as diverging type var", a.target);
278 let autoborrow_mut = adj.iter().any(|adj| {
282 kind: Adjust::Borrow(AutoBorrow::Ref(_, AutoBorrowMutability::Mut { .. })),
288 match self.typeck_results.borrow_mut().adjustments_mut().entry(expr.hir_id) {
289 Entry::Vacant(entry) => {
292 Entry::Occupied(mut entry) => {
293 debug!(" - composing on top of {:?}", entry.get());
294 match (&entry.get()[..], &adj[..]) {
295 // Applying any adjustment on top of a NeverToAny
296 // is a valid NeverToAny adjustment, because it can't
298 (&[Adjustment { kind: Adjust::NeverToAny, .. }], _) => return,
301 Adjustment { kind: Adjust::Deref(_), .. },
302 Adjustment { kind: Adjust::Borrow(AutoBorrow::Ref(..)), .. },
305 Adjustment { kind: Adjust::Deref(_), .. },
306 .., // Any following adjustments are allowed.
309 // A reborrow has no effect before a dereference.
311 // FIXME: currently we never try to compose autoderefs
312 // and ReifyFnPointer/UnsafeFnPointer, but we could.
314 self.tcx.sess.delay_span_bug(
317 "while adjusting {:?}, can't compose {:?} and {:?}",
325 *entry.get_mut() = adj;
329 // If there is an mutable auto-borrow, it is equivalent to `&mut <expr>`.
330 // In this case implicit use of `Deref` and `Index` within `<expr>` should
331 // instead be `DerefMut` and `IndexMut`, so fix those up.
333 self.convert_place_derefs_to_mutable(expr);
337 /// Basically whenever we are converting from a type scheme into
338 /// the fn body space, we always want to normalize associated
339 /// types as well. This function combines the two.
340 fn instantiate_type_scheme<T>(&self, span: Span, substs: SubstsRef<'tcx>, value: T) -> T
342 T: TypeFoldable<'tcx>,
344 debug!("instantiate_type_scheme(value={:?}, substs={:?})", value, substs);
345 let value = EarlyBinder(value).subst(self.tcx, substs);
346 let result = self.normalize_associated_types_in(span, value);
347 debug!("instantiate_type_scheme = {:?}", result);
351 /// As `instantiate_type_scheme`, but for the bounds found in a
352 /// generic type scheme.
353 pub(in super::super) fn instantiate_bounds(
357 substs: SubstsRef<'tcx>,
358 ) -> (ty::InstantiatedPredicates<'tcx>, Vec<Span>) {
359 let bounds = self.tcx.predicates_of(def_id);
360 let spans: Vec<Span> = bounds.predicates.iter().map(|(_, span)| *span).collect();
361 let result = bounds.instantiate(self.tcx, substs);
362 let result = self.normalize_associated_types_in(span, result);
364 "instantiate_bounds(bounds={:?}, substs={:?}) = {:?}, {:?}",
365 bounds, substs, result, spans,
370 pub(in super::super) fn normalize_associated_types_in<T>(&self, span: Span, value: T) -> T
372 T: TypeFoldable<'tcx>,
374 self.inh.normalize_associated_types_in(span, self.body_id, self.param_env, value)
377 pub(in super::super) fn normalize_associated_types_in_as_infer_ok<T>(
381 ) -> InferOk<'tcx, T>
383 T: TypeFoldable<'tcx>,
385 self.inh.partially_normalize_associated_types_in(
386 ObligationCause::misc(span, self.body_id),
392 pub(in super::super) fn normalize_op_associated_types_in_as_infer_ok<T>(
396 opt_input_expr: Option<&hir::Expr<'_>>,
397 ) -> InferOk<'tcx, T>
399 T: TypeFoldable<'tcx>,
401 self.inh.partially_normalize_associated_types_in(
402 ObligationCause::new(
406 rhs_span: opt_input_expr.map(|expr| expr.span),
407 is_lit: opt_input_expr
408 .map_or(false, |expr| matches!(expr.kind, ExprKind::Lit(_))),
417 pub fn require_type_meets(
421 code: traits::ObligationCauseCode<'tcx>,
424 self.register_bound(ty, def_id, traits::ObligationCause::new(span, self.body_id, code));
427 pub fn require_type_is_sized(
431 code: traits::ObligationCauseCode<'tcx>,
433 if !ty.references_error() {
434 let lang_item = self.tcx.require_lang_item(LangItem::Sized, None);
435 self.require_type_meets(ty, span, code, lang_item);
439 pub fn require_type_is_sized_deferred(
443 code: traits::ObligationCauseCode<'tcx>,
445 if !ty.references_error() {
446 self.deferred_sized_obligations.borrow_mut().push((ty, span, code));
450 pub fn register_bound(
454 cause: traits::ObligationCause<'tcx>,
456 if !ty.references_error() {
457 self.fulfillment_cx.borrow_mut().register_bound(
467 pub fn to_ty(&self, ast_t: &hir::Ty<'_>) -> Ty<'tcx> {
468 let t = <dyn AstConv<'_>>::ast_ty_to_ty(self, ast_t);
469 self.register_wf_obligation(t.into(), ast_t.span, traits::WellFormed(None));
473 pub fn to_ty_saving_user_provided_ty(&self, ast_ty: &hir::Ty<'_>) -> Ty<'tcx> {
474 let ty = self.to_ty(ast_ty);
475 debug!("to_ty_saving_user_provided_ty: ty={:?}", ty);
477 if Self::can_contain_user_lifetime_bounds(ty) {
478 let c_ty = self.canonicalize_response(UserType::Ty(ty));
479 debug!("to_ty_saving_user_provided_ty: c_ty={:?}", c_ty);
480 self.typeck_results.borrow_mut().user_provided_types_mut().insert(ast_ty.hir_id, c_ty);
486 pub fn array_length_to_const(&self, length: &hir::ArrayLen) -> ty::Const<'tcx> {
488 &hir::ArrayLen::Infer(_, span) => self.ct_infer(self.tcx.types.usize, None, span),
489 hir::ArrayLen::Body(anon_const) => {
490 let span = self.tcx.def_span(anon_const.def_id);
491 let c = ty::Const::from_anon_const(self.tcx, anon_const.def_id);
492 self.register_wf_obligation(c.into(), span, ObligationCauseCode::WellFormed(None));
493 self.normalize_associated_types_in(span, c)
498 pub fn const_arg_to_const(
500 ast_c: &hir::AnonConst,
502 ) -> ty::Const<'tcx> {
504 ty::WithOptConstParam { did: ast_c.def_id, const_param_did: Some(param_def_id) };
505 let c = ty::Const::from_opt_const_arg_anon_const(self.tcx, const_def);
506 self.register_wf_obligation(
508 self.tcx.hir().span(ast_c.hir_id),
509 ObligationCauseCode::WellFormed(None),
514 // If the type given by the user has free regions, save it for later, since
515 // NLL would like to enforce those. Also pass in types that involve
516 // projections, since those can resolve to `'static` bounds (modulo #54940,
517 // which hopefully will be fixed by the time you see this comment, dear
518 // reader, although I have my doubts). Also pass in types with inference
519 // types, because they may be repeated. Other sorts of things are already
520 // sufficiently enforced with erased regions. =)
521 fn can_contain_user_lifetime_bounds<T>(t: T) -> bool
523 T: TypeVisitable<'tcx>,
525 t.has_free_regions() || t.has_projections() || t.has_infer_types()
528 pub fn node_ty(&self, id: hir::HirId) -> Ty<'tcx> {
529 match self.typeck_results.borrow().node_types().get(id) {
531 None if let Some(e) = self.tainted_by_errors() => self.tcx.ty_error_with_guaranteed(e),
534 "no type for node {}: {} in fcx {}",
536 self.tcx.hir().node_to_string(id),
543 pub fn node_ty_opt(&self, id: hir::HirId) -> Option<Ty<'tcx>> {
544 match self.typeck_results.borrow().node_types().get(id) {
546 None if let Some(e) = self.tainted_by_errors() => Some(self.tcx.ty_error_with_guaranteed(e)),
551 /// Registers an obligation for checking later, during regionck, that `arg` is well-formed.
552 pub fn register_wf_obligation(
554 arg: ty::GenericArg<'tcx>,
556 code: traits::ObligationCauseCode<'tcx>,
558 // WF obligations never themselves fail, so no real need to give a detailed cause:
559 let cause = traits::ObligationCause::new(span, self.body_id, code);
560 self.register_predicate(traits::Obligation::new(
564 ty::Binder::dummy(ty::PredicateKind::WellFormed(arg)),
568 /// Registers obligations that all `substs` are well-formed.
569 pub fn add_wf_bounds(&self, substs: SubstsRef<'tcx>, expr: &hir::Expr<'_>) {
570 for arg in substs.iter().filter(|arg| {
571 matches!(arg.unpack(), GenericArgKind::Type(..) | GenericArgKind::Const(..))
573 self.register_wf_obligation(arg, expr.span, traits::WellFormed(None));
577 // FIXME(arielb1): use this instead of field.ty everywhere
578 // Only for fields! Returns <none> for methods>
579 // Indifferent to privacy flags
583 field: &'tcx ty::FieldDef,
584 substs: SubstsRef<'tcx>,
586 self.normalize_associated_types_in(span, field.ty(self.tcx, substs))
589 pub(in super::super) fn resolve_rvalue_scopes(&self, def_id: DefId) {
590 let scope_tree = self.tcx.region_scope_tree(def_id);
591 let rvalue_scopes = { rvalue_scopes::resolve_rvalue_scopes(self, &scope_tree, def_id) };
592 let mut typeck_results = self.inh.typeck_results.borrow_mut();
593 typeck_results.rvalue_scopes = rvalue_scopes;
596 pub(in super::super) fn resolve_generator_interiors(&self, def_id: DefId) {
597 let mut generators = self.deferred_generator_interiors.borrow_mut();
598 for (body_id, interior, kind) in generators.drain(..) {
599 self.select_obligations_where_possible(|_| {});
600 crate::generator_interior::resolve_interior(self, def_id, body_id, interior, kind);
604 #[instrument(skip(self), level = "debug")]
605 pub(in super::super) fn select_all_obligations_or_error(&self) {
606 let mut errors = self.fulfillment_cx.borrow_mut().select_all_or_error(&self);
608 if !errors.is_empty() {
609 self.adjust_fulfillment_errors_for_expr_obligation(&mut errors);
610 self.err_ctxt().report_fulfillment_errors(&errors, self.inh.body_id);
614 /// Select as many obligations as we can at present.
615 pub(in super::super) fn select_obligations_where_possible(
617 mutate_fulfillment_errors: impl Fn(&mut Vec<traits::FulfillmentError<'tcx>>),
619 let mut result = self.fulfillment_cx.borrow_mut().select_where_possible(self);
620 if !result.is_empty() {
621 mutate_fulfillment_errors(&mut result);
622 self.adjust_fulfillment_errors_for_expr_obligation(&mut result);
623 self.err_ctxt().report_fulfillment_errors(&result, self.inh.body_id);
627 /// For the overloaded place expressions (`*x`, `x[3]`), the trait
628 /// returns a type of `&T`, but the actual type we assign to the
629 /// *expression* is `T`. So this function just peels off the return
630 /// type by one layer to yield `T`.
631 pub(in super::super) fn make_overloaded_place_return_type(
633 method: MethodCallee<'tcx>,
634 ) -> ty::TypeAndMut<'tcx> {
635 // extract method return type, which will be &T;
636 let ret_ty = method.sig.output();
638 // method returns &T, but the type as visible to user is T, so deref
639 ret_ty.builtin_deref(true).unwrap()
642 #[instrument(skip(self), level = "debug")]
643 fn self_type_matches_expected_vid(&self, self_ty: Ty<'tcx>, expected_vid: ty::TyVid) -> bool {
644 let self_ty = self.shallow_resolve(self_ty);
647 match *self_ty.kind() {
648 ty::Infer(ty::TyVar(found_vid)) => {
649 // FIXME: consider using `sub_root_var` here so we
650 // can see through subtyping.
651 let found_vid = self.root_var(found_vid);
652 debug!("self_type_matches_expected_vid - found_vid={:?}", found_vid);
653 expected_vid == found_vid
659 #[instrument(skip(self), level = "debug")]
660 pub(in super::super) fn obligations_for_self_ty<'b>(
663 ) -> impl DoubleEndedIterator<Item = traits::PredicateObligation<'tcx>> + Captures<'tcx> + 'b
665 // FIXME: consider using `sub_root_var` here so we
666 // can see through subtyping.
667 let ty_var_root = self.root_var(self_ty);
668 trace!("pending_obligations = {:#?}", self.fulfillment_cx.borrow().pending_obligations());
670 self.fulfillment_cx.borrow().pending_obligations().into_iter().filter_map(
671 move |obligation| match &obligation.predicate.kind().skip_binder() {
672 ty::PredicateKind::Projection(data)
673 if self.self_type_matches_expected_vid(
674 data.projection_ty.self_ty(),
680 ty::PredicateKind::Trait(data)
681 if self.self_type_matches_expected_vid(data.self_ty(), ty_var_root) =>
686 ty::PredicateKind::Trait(..)
687 | ty::PredicateKind::Projection(..)
688 | ty::PredicateKind::Subtype(..)
689 | ty::PredicateKind::Coerce(..)
690 | ty::PredicateKind::RegionOutlives(..)
691 | ty::PredicateKind::TypeOutlives(..)
692 | ty::PredicateKind::WellFormed(..)
693 | ty::PredicateKind::ObjectSafe(..)
694 | ty::PredicateKind::ConstEvaluatable(..)
695 | ty::PredicateKind::ConstEquate(..)
696 // N.B., this predicate is created by breaking down a
697 // `ClosureType: FnFoo()` predicate, where
698 // `ClosureType` represents some `Closure`. It can't
699 // possibly be referring to the current closure,
700 // because we haven't produced the `Closure` for
701 // this closure yet; this is exactly why the other
702 // code is looking for a self type of an unresolved
703 // inference variable.
704 | ty::PredicateKind::ClosureKind(..)
705 | ty::PredicateKind::TypeWellFormedFromEnv(..) => None,
710 pub(in super::super) fn type_var_is_sized(&self, self_ty: ty::TyVid) -> bool {
711 let sized_did = self.tcx.lang_items().sized_trait();
712 self.obligations_for_self_ty(self_ty).any(|obligation| {
713 match obligation.predicate.kind().skip_binder() {
714 ty::PredicateKind::Trait(data) => Some(data.def_id()) == sized_did,
720 pub(in super::super) fn err_args(&self, len: usize) -> Vec<Ty<'tcx>> {
721 vec![self.tcx.ty_error(); len]
724 /// Unifies the output type with the expected type early, for more coercions
725 /// and forward type information on the input expressions.
726 #[instrument(skip(self, call_span), level = "debug")]
727 pub(in super::super) fn expected_inputs_for_expected_output(
730 expected_ret: Expectation<'tcx>,
731 formal_ret: Ty<'tcx>,
732 formal_args: &[Ty<'tcx>],
733 ) -> Option<Vec<Ty<'tcx>>> {
734 let formal_ret = self.resolve_vars_with_obligations(formal_ret);
735 let ret_ty = expected_ret.only_has_type(self)?;
737 // HACK(oli-obk): This is a hack to keep RPIT and TAIT in sync wrt their behaviour.
738 // Without it, the inference
739 // variable will get instantiated with the opaque type. The inference variable often
740 // has various helpful obligations registered for it that help closures figure out their
741 // signature. If we infer the inference var to the opaque type, the closure won't be able
742 // to find those obligations anymore, and it can't necessarily find them from the opaque
743 // type itself. We could be more powerful with inference if we *combined* the obligations
744 // so that we got both the obligations from the opaque type and the ones from the inference
745 // variable. That will accept more code than we do right now, so we need to carefully consider
747 // Note: this check is pessimistic, as the inference type could be matched with something other
748 // than the opaque type, but then we need a new `TypeRelation` just for this specific case and
749 // can't re-use `sup` below.
750 // See src/test/ui/impl-trait/hidden-type-is-opaque.rs and
751 // src/test/ui/impl-trait/hidden-type-is-opaque-2.rs for examples that hit this path.
752 if formal_ret.has_infer_types() {
753 for ty in ret_ty.walk() {
754 if let ty::subst::GenericArgKind::Type(ty) = ty.unpack()
755 && let ty::Opaque(def_id, _) = *ty.kind()
756 && let Some(def_id) = def_id.as_local()
757 && self.opaque_type_origin(def_id, DUMMY_SP).is_some() {
763 let expect_args = self
764 .fudge_inference_if_ok(|| {
765 let ocx = ObligationCtxt::new_in_snapshot(self);
767 // Attempt to apply a subtyping relationship between the formal
768 // return type (likely containing type variables if the function
769 // is polymorphic) and the expected return type.
770 // No argument expectations are produced if unification fails.
771 let origin = self.misc(call_span);
772 ocx.sup(&origin, self.param_env, ret_ty, formal_ret)?;
773 if !ocx.select_where_possible().is_empty() {
774 return Err(TypeError::Mismatch);
777 // Record all the argument types, with the substitutions
778 // produced from the above subtyping unification.
779 Ok(Some(formal_args.iter().map(|&ty| self.resolve_vars_if_possible(ty)).collect()))
781 .unwrap_or_default();
782 debug!(?formal_args, ?formal_ret, ?expect_args, ?expected_ret);
786 pub(in super::super) fn resolve_lang_item_path(
788 lang_item: hir::LangItem,
791 expr_hir_id: Option<hir::HirId>,
792 ) -> (Res, Ty<'tcx>) {
793 let def_id = self.tcx.require_lang_item(lang_item, Some(span));
794 let def_kind = self.tcx.def_kind(def_id);
796 let item_ty = if let DefKind::Variant = def_kind {
797 self.tcx.bound_type_of(self.tcx.parent(def_id))
799 self.tcx.bound_type_of(def_id)
801 let substs = self.fresh_substs_for_item(span, def_id);
802 let ty = item_ty.subst(self.tcx, substs);
804 self.write_resolution(hir_id, Ok((def_kind, def_id)));
806 let code = match lang_item {
807 hir::LangItem::IntoFutureIntoFuture => {
808 Some(ObligationCauseCode::AwaitableExpr(expr_hir_id))
810 hir::LangItem::IteratorNext | hir::LangItem::IntoIterIntoIter => {
811 Some(ObligationCauseCode::ForLoopIterator)
813 hir::LangItem::TryTraitFromOutput
814 | hir::LangItem::TryTraitFromResidual
815 | hir::LangItem::TryTraitBranch => Some(ObligationCauseCode::QuestionMark),
818 if let Some(code) = code {
819 self.add_required_obligations_with_code(span, def_id, substs, move |_, _| code.clone());
821 self.add_required_obligations_for_hir(span, def_id, substs, hir_id);
824 (Res::Def(def_kind, def_id), ty)
827 /// Resolves an associated value path into a base type and associated constant, or method
828 /// resolution. The newly resolved definition is written into `type_dependent_defs`.
829 pub fn resolve_ty_and_res_fully_qualified_call(
831 qpath: &'tcx QPath<'tcx>,
834 ) -> (Res, Option<Ty<'tcx>>, &'tcx [hir::PathSegment<'tcx>]) {
836 "resolve_ty_and_res_fully_qualified_call: qpath={:?} hir_id={:?} span={:?}",
839 let (ty, qself, item_segment) = match *qpath {
840 QPath::Resolved(ref opt_qself, ref path) => {
843 opt_qself.as_ref().map(|qself| self.to_ty(qself)),
847 QPath::TypeRelative(ref qself, ref segment) => {
848 // Don't use `self.to_ty`, since this will register a WF obligation.
849 // If we're trying to call a non-existent method on a trait
850 // (e.g. `MyTrait::missing_method`), then resolution will
851 // give us a `QPath::TypeRelative` with a trait object as
852 // `qself`. In that case, we want to avoid registering a WF obligation
853 // for `dyn MyTrait`, since we don't actually need the trait
854 // to be object-safe.
855 // We manually call `register_wf_obligation` in the success path
857 (<dyn AstConv<'_>>::ast_ty_to_ty_in_path(self, qself), qself, segment)
859 QPath::LangItem(..) => {
860 bug!("`resolve_ty_and_res_fully_qualified_call` called on `LangItem`")
863 if let Some(&cached_result) = self.typeck_results.borrow().type_dependent_defs().get(hir_id)
865 self.register_wf_obligation(ty.into(), qself.span, traits::WellFormed(None));
866 // Return directly on cache hit. This is useful to avoid doubly reporting
867 // errors with default match binding modes. See #44614.
868 let def = cached_result.map_or(Res::Err, |(kind, def_id)| Res::Def(kind, def_id));
869 return (def, Some(ty), slice::from_ref(&**item_segment));
871 let item_name = item_segment.ident;
873 .resolve_fully_qualified_call(span, item_name, ty, qself.span, hir_id)
875 let result = match error {
876 method::MethodError::PrivateMatch(kind, def_id, _) => Ok((kind, def_id)),
877 _ => Err(ErrorGuaranteed::unchecked_claim_error_was_emitted()),
880 // If we have a path like `MyTrait::missing_method`, then don't register
881 // a WF obligation for `dyn MyTrait` when method lookup fails. Otherwise,
882 // register a WF obligation so that we can detect any additional
883 // errors in the self type.
884 if !(matches!(error, method::MethodError::NoMatch(_)) && ty.is_trait()) {
885 self.register_wf_obligation(ty.into(), qself.span, traits::WellFormed(None));
887 if item_name.name != kw::Empty {
888 if let Some(mut e) = self.report_method_error(
892 SelfSource::QPath(qself),
903 self.register_wf_obligation(ty.into(), qself.span, traits::WellFormed(None));
906 // Write back the new resolution.
907 self.write_resolution(hir_id, result);
909 result.map_or(Res::Err, |(kind, def_id)| Res::Def(kind, def_id)),
911 slice::from_ref(&**item_segment),
915 /// Given a function `Node`, return its `FnDecl` if it exists, or `None` otherwise.
916 pub(in super::super) fn get_node_fn_decl(
919 ) -> Option<(&'tcx hir::FnDecl<'tcx>, Ident, bool)> {
921 Node::Item(&hir::Item { ident, kind: hir::ItemKind::Fn(ref sig, ..), .. }) => {
922 // This is less than ideal, it will not suggest a return type span on any
923 // method called `main`, regardless of whether it is actually the entry point,
924 // but it will still present it as the reason for the expected type.
925 Some((&sig.decl, ident, ident.name != sym::main))
927 Node::TraitItem(&hir::TraitItem {
929 kind: hir::TraitItemKind::Fn(ref sig, ..),
931 }) => Some((&sig.decl, ident, true)),
932 Node::ImplItem(&hir::ImplItem {
934 kind: hir::ImplItemKind::Fn(ref sig, ..),
936 }) => Some((&sig.decl, ident, false)),
941 /// Given a `HirId`, return the `FnDecl` of the method it is enclosed by and whether a
942 /// suggestion can be made, `None` otherwise.
943 pub fn get_fn_decl(&self, blk_id: hir::HirId) -> Option<(&'tcx hir::FnDecl<'tcx>, bool)> {
944 // Get enclosing Fn, if it is a function or a trait method, unless there's a `loop` or
945 // `while` before reaching it, as block tail returns are not available in them.
946 self.tcx.hir().get_return_block(blk_id).and_then(|blk_id| {
947 let parent = self.tcx.hir().get(blk_id);
948 self.get_node_fn_decl(parent).map(|(fn_decl, _, is_main)| (fn_decl, is_main))
952 pub(in super::super) fn note_internal_mutation_in_method(
954 err: &mut Diagnostic,
955 expr: &hir::Expr<'_>,
959 if found != self.tcx.types.unit {
962 if let ExprKind::MethodCall(path_segment, rcvr, ..) = expr.kind {
966 .expr_ty_adjusted_opt(rcvr)
967 .map_or(true, |ty| expected.peel_refs() != ty.peel_refs())
971 let mut sp = MultiSpan::from_span(path_segment.ident.span);
973 path_segment.ident.span,
975 "this call modifies {} in-place",
977 ExprKind::Path(QPath::Resolved(
979 hir::Path { segments: [segment], .. },
980 )) => format!("`{}`", segment.ident),
981 _ => "its receiver".to_string(),
987 "you probably want to use this value after calling the method...",
991 &format!("method `{}` modifies its receiver in-place", path_segment.ident),
993 err.note(&format!("...instead of the `()` output of method `{}`", path_segment.ident));
997 pub(in super::super) fn note_need_for_fn_pointer(
999 err: &mut Diagnostic,
1003 let (sig, did, substs) = match (&expected.kind(), &found.kind()) {
1004 (ty::FnDef(did1, substs1), ty::FnDef(did2, substs2)) => {
1005 let sig1 = self.tcx.bound_fn_sig(*did1).subst(self.tcx, substs1);
1006 let sig2 = self.tcx.bound_fn_sig(*did2).subst(self.tcx, substs2);
1011 "different `fn` items always have unique types, even if their signatures are \
1014 (sig1, *did1, substs1)
1016 (ty::FnDef(did, substs), ty::FnPtr(sig2)) => {
1017 let sig1 = self.tcx.bound_fn_sig(*did).subst(self.tcx, substs);
1021 (sig1, *did, substs)
1025 err.help(&format!("change the expected type to be function pointer `{}`", sig));
1027 "if the expected type is due to type inference, cast the expected `fn` to a function \
1028 pointer: `{} as {}`",
1029 self.tcx.def_path_str_with_substs(did, substs),
1034 // Instantiates the given path, which must refer to an item with the given
1035 // number of type parameters and type.
1036 #[instrument(skip(self, span), level = "debug")]
1037 pub fn instantiate_value_path(
1039 segments: &[hir::PathSegment<'_>],
1040 self_ty: Option<Ty<'tcx>>,
1044 ) -> (Ty<'tcx>, Res) {
1047 let path_segs = match res {
1048 Res::Local(_) | Res::SelfCtor(_) => vec![],
1049 Res::Def(kind, def_id) => <dyn AstConv<'_>>::def_ids_for_value_path_segments(
1050 self, segments, self_ty, kind, def_id,
1052 _ => bug!("instantiate_value_path on {:?}", res),
1055 let mut user_self_ty = None;
1056 let mut is_alias_variant_ctor = false;
1058 Res::Def(DefKind::Ctor(CtorOf::Variant, _), _)
1059 if let Some(self_ty) = self_ty =>
1061 let adt_def = self_ty.ty_adt_def().unwrap();
1062 user_self_ty = Some(UserSelfTy { impl_def_id: adt_def.did(), self_ty });
1063 is_alias_variant_ctor = true;
1065 Res::Def(DefKind::AssocFn | DefKind::AssocConst, def_id) => {
1066 let assoc_item = tcx.associated_item(def_id);
1067 let container = assoc_item.container;
1068 let container_id = assoc_item.container_id(tcx);
1069 debug!(?def_id, ?container, ?container_id);
1071 ty::TraitContainer => {
1072 callee::check_legal_trait_for_method_call(tcx, span, None, span, container_id)
1074 ty::ImplContainer => {
1075 if segments.len() == 1 {
1076 // `<T>::assoc` will end up here, and so
1077 // can `T::assoc`. It this came from an
1078 // inherent impl, we need to record the
1079 // `T` for posterity (see `UserSelfTy` for
1081 let self_ty = self_ty.expect("UFCS sugared assoc missing Self");
1082 user_self_ty = Some(UserSelfTy { impl_def_id: container_id, self_ty });
1090 // Now that we have categorized what space the parameters for each
1091 // segment belong to, let's sort out the parameters that the user
1092 // provided (if any) into their appropriate spaces. We'll also report
1093 // errors if type parameters are provided in an inappropriate place.
1095 let generic_segs: FxHashSet<_> = path_segs.iter().map(|PathSeg(_, index)| index).collect();
1096 let generics_has_err = <dyn AstConv<'_>>::prohibit_generics(
1098 segments.iter().enumerate().filter_map(|(index, seg)| {
1099 if !generic_segs.contains(&index) || is_alias_variant_ctor {
1108 if let Res::Local(hid) = res {
1109 let ty = self.local_ty(span, hid).decl_ty;
1110 let ty = self.normalize_associated_types_in(span, ty);
1111 self.write_ty(hir_id, ty);
1115 if generics_has_err {
1116 // Don't try to infer type parameters when prohibited generic arguments were given.
1117 user_self_ty = None;
1120 // Now we have to compare the types that the user *actually*
1121 // provided against the types that were *expected*. If the user
1122 // did not provide any types, then we want to substitute inference
1123 // variables. If the user provided some types, we may still need
1124 // to add defaults. If the user provided *too many* types, that's
1127 let mut infer_args_for_err = FxHashSet::default();
1129 let mut explicit_late_bound = ExplicitLateBound::No;
1130 for &PathSeg(def_id, index) in &path_segs {
1131 let seg = &segments[index];
1132 let generics = tcx.generics_of(def_id);
1134 // Argument-position `impl Trait` is treated as a normal generic
1135 // parameter internally, but we don't allow users to specify the
1136 // parameter's value explicitly, so we have to do some error-
1138 let arg_count = <dyn AstConv<'_>>::check_generic_arg_count_for_call(
1147 if let ExplicitLateBound::Yes = arg_count.explicit_late_bound {
1148 explicit_late_bound = ExplicitLateBound::Yes;
1151 if let Err(GenericArgCountMismatch { reported: Some(e), .. }) = arg_count.correct {
1152 infer_args_for_err.insert(index);
1153 self.set_tainted_by_errors(e); // See issue #53251.
1157 let has_self = path_segs
1159 .map(|PathSeg(def_id, _)| tcx.generics_of(*def_id).has_self)
1162 let (res, self_ctor_substs) = if let Res::SelfCtor(impl_def_id) = res {
1163 let ty = self.normalize_ty(span, tcx.at(span).type_of(impl_def_id));
1165 ty::Adt(adt_def, substs) if adt_def.has_ctor() => {
1166 let variant = adt_def.non_enum_variant();
1167 let (ctor_kind, ctor_def_id) = variant.ctor.unwrap();
1168 (Res::Def(DefKind::Ctor(CtorOf::Struct, ctor_kind), ctor_def_id), Some(substs))
1171 let mut err = tcx.sess.struct_span_err(
1173 "the `Self` constructor can only be used with tuple or unit structs",
1175 if let Some(adt_def) = ty.ty_adt_def() {
1176 match adt_def.adt_kind() {
1178 err.help("did you mean to use one of the enum's variants?");
1180 AdtKind::Struct | AdtKind::Union => {
1181 err.span_suggestion(
1183 "use curly brackets",
1184 "Self { /* fields */ }",
1185 Applicability::HasPlaceholders,
1190 let reported = err.emit();
1191 return (tcx.ty_error_with_guaranteed(reported), res);
1197 let def_id = res.def_id();
1199 // The things we are substituting into the type should not contain
1200 // escaping late-bound regions, and nor should the base type scheme.
1201 let ty = tcx.type_of(def_id);
1203 let arg_count = GenericArgCountResult {
1204 explicit_late_bound,
1205 correct: if infer_args_for_err.is_empty() {
1208 Err(GenericArgCountMismatch::default())
1212 struct CreateCtorSubstsContext<'a, 'tcx> {
1213 fcx: &'a FnCtxt<'a, 'tcx>,
1215 path_segs: &'a [PathSeg],
1216 infer_args_for_err: &'a FxHashSet<usize>,
1217 segments: &'a [hir::PathSegment<'a>],
1219 impl<'tcx, 'a> CreateSubstsForGenericArgsCtxt<'a, 'tcx> for CreateCtorSubstsContext<'a, 'tcx> {
1223 ) -> (Option<&'a hir::GenericArgs<'a>>, bool) {
1224 if let Some(&PathSeg(_, index)) =
1225 self.path_segs.iter().find(|&PathSeg(did, _)| *did == def_id)
1227 // If we've encountered an `impl Trait`-related error, we're just
1228 // going to infer the arguments for better error messages.
1229 if !self.infer_args_for_err.contains(&index) {
1230 // Check whether the user has provided generic arguments.
1231 if let Some(ref data) = self.segments[index].args {
1232 return (Some(data), self.segments[index].infer_args);
1235 return (None, self.segments[index].infer_args);
1243 param: &ty::GenericParamDef,
1244 arg: &GenericArg<'_>,
1245 ) -> ty::GenericArg<'tcx> {
1246 match (¶m.kind, arg) {
1247 (GenericParamDefKind::Lifetime, GenericArg::Lifetime(lt)) => {
1248 <dyn AstConv<'_>>::ast_region_to_region(self.fcx, lt, Some(param)).into()
1250 (GenericParamDefKind::Type { .. }, GenericArg::Type(ty)) => {
1251 self.fcx.to_ty(ty).into()
1253 (GenericParamDefKind::Const { .. }, GenericArg::Const(ct)) => {
1254 self.fcx.const_arg_to_const(&ct.value, param.def_id).into()
1256 (GenericParamDefKind::Type { .. }, GenericArg::Infer(inf)) => {
1257 self.fcx.ty_infer(Some(param), inf.span).into()
1259 (GenericParamDefKind::Const { .. }, GenericArg::Infer(inf)) => {
1260 let tcx = self.fcx.tcx();
1261 self.fcx.ct_infer(tcx.type_of(param.def_id), Some(param), inf.span).into()
1263 _ => unreachable!(),
1269 substs: Option<&[ty::GenericArg<'tcx>]>,
1270 param: &ty::GenericParamDef,
1272 ) -> ty::GenericArg<'tcx> {
1273 let tcx = self.fcx.tcx();
1275 GenericParamDefKind::Lifetime => {
1276 self.fcx.re_infer(Some(param), self.span).unwrap().into()
1278 GenericParamDefKind::Type { has_default, .. } => {
1279 if !infer_args && has_default {
1280 // If we have a default, then we it doesn't matter that we're not
1281 // inferring the type arguments: we provide the default where any
1283 let default = tcx.bound_type_of(param.def_id);
1285 .normalize_ty(self.span, default.subst(tcx, substs.unwrap()))
1288 // If no type arguments were provided, we have to infer them.
1289 // This case also occurs as a result of some malformed input, e.g.
1290 // a lifetime argument being given instead of a type parameter.
1291 // Using inference instead of `Error` gives better error messages.
1292 self.fcx.var_for_def(self.span, param)
1295 GenericParamDefKind::Const { has_default } => {
1296 if !infer_args && has_default {
1297 tcx.bound_const_param_default(param.def_id)
1298 .subst(tcx, substs.unwrap())
1301 self.fcx.var_for_def(self.span, param)
1308 let substs = self_ctor_substs.unwrap_or_else(|| {
1309 <dyn AstConv<'_>>::create_substs_for_generic_args(
1316 &mut CreateCtorSubstsContext {
1319 path_segs: &path_segs,
1320 infer_args_for_err: &infer_args_for_err,
1325 assert!(!substs.has_escaping_bound_vars());
1326 assert!(!ty.has_escaping_bound_vars());
1328 // First, store the "user substs" for later.
1329 self.write_user_type_annotation_from_substs(hir_id, def_id, substs, user_self_ty);
1331 self.add_required_obligations_for_hir(span, def_id, &substs, hir_id);
1333 // Substitute the values for the type parameters into the type of
1334 // the referenced item.
1335 let ty_substituted = self.instantiate_type_scheme(span, &substs, ty);
1337 if let Some(UserSelfTy { impl_def_id, self_ty }) = user_self_ty {
1338 // In the case of `Foo<T>::method` and `<Foo<T>>::method`, if `method`
1339 // is inherent, there is no `Self` parameter; instead, the impl needs
1340 // type parameters, which we can infer by unifying the provided `Self`
1341 // with the substituted impl type.
1342 // This also occurs for an enum variant on a type alias.
1343 let ty = tcx.type_of(impl_def_id);
1345 let impl_ty = self.instantiate_type_scheme(span, &substs, ty);
1346 match self.at(&self.misc(span), self.param_env).eq(impl_ty, self_ty) {
1347 Ok(ok) => self.register_infer_ok_obligations(ok),
1349 self.tcx.sess.delay_span_bug(
1352 "instantiate_value_path: (UFCS) {:?} was a subtype of {:?} but now is not?",
1361 debug!("instantiate_value_path: type of {:?} is {:?}", hir_id, ty_substituted);
1362 self.write_substs(hir_id, substs);
1364 (ty_substituted, res)
1367 /// Add all the obligations that are required, substituting and normalized appropriately.
1368 pub(crate) fn add_required_obligations_for_hir(
1372 substs: SubstsRef<'tcx>,
1375 self.add_required_obligations_with_code(span, def_id, substs, |idx, span| {
1376 if span.is_dummy() {
1377 ObligationCauseCode::ExprItemObligation(def_id, hir_id, idx)
1379 ObligationCauseCode::ExprBindingObligation(def_id, span, hir_id, idx)
1384 #[instrument(level = "debug", skip(self, code, span, substs))]
1385 fn add_required_obligations_with_code(
1389 substs: SubstsRef<'tcx>,
1390 code: impl Fn(usize, Span) -> ObligationCauseCode<'tcx>,
1392 let param_env = self.param_env;
1394 let remap = match self.tcx.def_kind(def_id) {
1395 // Associated consts have `Self: ~const Trait` bounds that should be satisfiable when
1396 // `Self: Trait` is satisfied because it does not matter whether the impl is `const`.
1397 // Therefore we have to remap the param env here to be non-const.
1398 hir::def::DefKind::AssocConst => true,
1399 hir::def::DefKind::AssocFn
1400 if self.tcx.def_kind(self.tcx.parent(def_id)) == hir::def::DefKind::Trait =>
1402 // N.B.: All callsites to this function involve checking a path expression.
1404 // When instantiating a trait method as a function item, it does not actually matter whether
1405 // the trait is `const` or not, or whether `where T: ~const Tr` needs to be satisfied as
1406 // `const`. If we were to introduce instantiating trait methods as `const fn`s, we would
1407 // check that after this, either via a bound `where F: ~const FnOnce` or when coercing to a
1408 // `const fn` pointer.
1410 // FIXME(fee1-dead) FIXME(const_trait_impl): update this doc when trait methods can satisfy
1411 // `~const FnOnce` or can be coerced to `const fn` pointer.
1416 let (bounds, _) = self.instantiate_bounds(span, def_id, &substs);
1418 for mut obligation in traits::predicates_for_generics(
1419 |idx, predicate_span| {
1420 traits::ObligationCause::new(span, self.body_id, code(idx, predicate_span))
1426 obligation = obligation.without_const(self.tcx);
1428 self.register_predicate(obligation);
1432 /// Resolves `typ` by a single level if `typ` is a type variable.
1433 /// If no resolution is possible, then an error is reported.
1434 /// Numeric inference variables may be left unresolved.
1435 pub fn structurally_resolved_type(&self, sp: Span, ty: Ty<'tcx>) -> Ty<'tcx> {
1436 let ty = self.resolve_vars_with_obligations(ty);
1437 if !ty.is_ty_var() {
1440 let e = self.tainted_by_errors().unwrap_or_else(|| {
1442 .emit_inference_failure_err((**self).body_id, sp, ty.into(), E0282, true)
1445 let err = self.tcx.ty_error_with_guaranteed(e);
1446 self.demand_suptype(sp, err, ty);
1451 pub(in super::super) fn with_breakable_ctxt<F: FnOnce() -> R, R>(
1454 ctxt: BreakableCtxt<'tcx>,
1456 ) -> (BreakableCtxt<'tcx>, R) {
1459 let mut enclosing_breakables = self.enclosing_breakables.borrow_mut();
1460 index = enclosing_breakables.stack.len();
1461 enclosing_breakables.by_id.insert(id, index);
1462 enclosing_breakables.stack.push(ctxt);
1466 let mut enclosing_breakables = self.enclosing_breakables.borrow_mut();
1467 debug_assert!(enclosing_breakables.stack.len() == index + 1);
1468 enclosing_breakables.by_id.remove(&id).expect("missing breakable context");
1469 enclosing_breakables.stack.pop().expect("missing breakable context")
1474 /// Instantiate a QueryResponse in a probe context, without a
1475 /// good ObligationCause.
1476 pub(in super::super) fn probe_instantiate_query_response(
1479 original_values: &OriginalQueryValues<'tcx>,
1480 query_result: &Canonical<'tcx, QueryResponse<'tcx, Ty<'tcx>>>,
1481 ) -> InferResult<'tcx, Ty<'tcx>> {
1482 self.instantiate_query_response_and_region_obligations(
1483 &traits::ObligationCause::misc(span, self.body_id),
1490 /// Returns `true` if an expression is contained inside the LHS of an assignment expression.
1491 pub(in super::super) fn expr_in_place(&self, mut expr_id: hir::HirId) -> bool {
1492 let mut contained_in_place = false;
1494 while let hir::Node::Expr(parent_expr) =
1495 self.tcx.hir().get(self.tcx.hir().get_parent_node(expr_id))
1497 match &parent_expr.kind {
1498 hir::ExprKind::Assign(lhs, ..) | hir::ExprKind::AssignOp(_, lhs, ..) => {
1499 if lhs.hir_id == expr_id {
1500 contained_in_place = true;
1506 expr_id = parent_expr.hir_id;