1 //! This pass type-checks the MIR to ensure it is not broken.
4 use std::{fmt, iter, mem};
8 use hir::OpaqueTyOrigin;
9 use rustc_data_structures::frozen::Frozen;
10 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
11 use rustc_data_structures::vec_map::VecMap;
12 use rustc_errors::struct_span_err;
14 use rustc_hir::def::DefKind;
15 use rustc_hir::def_id::LocalDefId;
16 use rustc_hir::lang_items::LangItem;
17 use rustc_index::vec::{Idx, IndexVec};
18 use rustc_infer::infer::canonical::QueryRegionConstraints;
19 use rustc_infer::infer::outlives::env::RegionBoundPairs;
20 use rustc_infer::infer::region_constraints::RegionConstraintData;
21 use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
22 use rustc_infer::infer::{
23 InferCtxt, InferOk, LateBoundRegionConversionTime, NllRegionVariableOrigin,
25 use rustc_middle::mir::tcx::PlaceTy;
26 use rustc_middle::mir::visit::{NonMutatingUseContext, PlaceContext, Visitor};
27 use rustc_middle::mir::AssertKind;
28 use rustc_middle::mir::*;
29 use rustc_middle::ty::adjustment::PointerCast;
30 use rustc_middle::ty::cast::CastTy;
31 use rustc_middle::ty::fold::TypeFoldable;
32 use rustc_middle::ty::subst::{GenericArgKind, SubstsRef, UserSubsts};
33 use rustc_middle::ty::{
34 self, CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations, OpaqueHiddenType,
35 OpaqueTypeKey, RegionVid, ToPredicate, Ty, TyCtxt, UserType, UserTypeAnnotationIndex,
37 use rustc_span::def_id::CRATE_DEF_ID;
38 use rustc_span::{Span, DUMMY_SP};
39 use rustc_target::abi::VariantIdx;
40 use rustc_trait_selection::traits::query::type_op;
41 use rustc_trait_selection::traits::query::type_op::custom::scrape_region_constraints;
42 use rustc_trait_selection::traits::query::type_op::custom::CustomTypeOp;
43 use rustc_trait_selection::traits::query::type_op::{TypeOp, TypeOpOutput};
44 use rustc_trait_selection::traits::query::Fallible;
45 use rustc_trait_selection::traits::PredicateObligation;
47 use rustc_mir_dataflow::impls::MaybeInitializedPlaces;
48 use rustc_mir_dataflow::move_paths::MoveData;
49 use rustc_mir_dataflow::ResultsCursor;
52 borrow_set::BorrowSet,
53 constraints::{OutlivesConstraint, OutlivesConstraintSet},
54 diagnostics::UniverseInfo,
56 location::LocationTable,
57 member_constraints::MemberConstraintSet,
60 region_infer::values::{
61 LivenessValues, PlaceholderIndex, PlaceholderIndices, RegionValueElements,
63 region_infer::{ClosureRegionRequirementsExt, TypeTest},
64 type_check::free_region_relations::{CreateResult, UniversalRegionRelations},
65 universal_regions::{DefiningTy, UniversalRegions},
69 macro_rules! span_mirbug {
70 ($context:expr, $elem:expr, $($message:tt)*) => ({
71 $crate::type_check::mirbug(
75 "broken MIR in {:?} ({:?}): {}",
76 $context.body().source.def_id(),
78 format_args!($($message)*),
84 macro_rules! span_mirbug_and_err {
85 ($context:expr, $elem:expr, $($message:tt)*) => ({
87 span_mirbug!($context, $elem, $($message)*);
94 mod constraint_conversion;
95 pub mod free_region_relations;
100 /// Type checks the given `mir` in the context of the inference
101 /// context `infcx`. Returns any region constraints that have yet to
102 /// be proven. This result includes liveness constraints that
103 /// ensure that regions appearing in the types of all local variables
104 /// are live at all points where that local variable may later be
107 /// This phase of type-check ought to be infallible -- this is because
108 /// the original, HIR-based type-check succeeded. So if any errors
109 /// occur here, we will get a `bug!` reported.
113 /// - `infcx` -- inference context to use
114 /// - `param_env` -- parameter environment to use for trait solving
115 /// - `body` -- MIR body to type-check
116 /// - `promoted` -- map of promoted constants within `body`
117 /// - `universal_regions` -- the universal regions from `body`s function signature
118 /// - `location_table` -- MIR location map of `body`
119 /// - `borrow_set` -- information about borrows occurring in `body`
120 /// - `all_facts` -- when using Polonius, this is the generated set of Polonius facts
121 /// - `flow_inits` -- results of a maybe-init dataflow analysis
122 /// - `move_data` -- move-data constructed when performing the maybe-init dataflow analysis
123 /// - `elements` -- MIR region map
124 pub(crate) fn type_check<'mir, 'tcx>(
125 infcx: &InferCtxt<'_, 'tcx>,
126 param_env: ty::ParamEnv<'tcx>,
128 promoted: &IndexVec<Promoted, Body<'tcx>>,
129 universal_regions: &Rc<UniversalRegions<'tcx>>,
130 location_table: &LocationTable,
131 borrow_set: &BorrowSet<'tcx>,
132 all_facts: &mut Option<AllFacts>,
133 flow_inits: &mut ResultsCursor<'mir, 'tcx, MaybeInitializedPlaces<'mir, 'tcx>>,
134 move_data: &MoveData<'tcx>,
135 elements: &Rc<RegionValueElements>,
136 upvars: &[Upvar<'tcx>],
138 ) -> MirTypeckResults<'tcx> {
139 let implicit_region_bound = infcx.tcx.mk_region(ty::ReVar(universal_regions.fr_fn_body));
140 let mut universe_causes = FxHashMap::default();
141 universe_causes.insert(ty::UniverseIndex::from_u32(0), UniverseInfo::other());
142 let mut constraints = MirTypeckRegionConstraints {
143 placeholder_indices: PlaceholderIndices::default(),
144 placeholder_index_to_region: IndexVec::default(),
145 liveness_constraints: LivenessValues::new(elements.clone()),
146 outlives_constraints: OutlivesConstraintSet::default(),
147 member_constraints: MemberConstraintSet::default(),
148 closure_bounds_mapping: Default::default(),
149 type_tests: Vec::default(),
154 universal_region_relations,
156 normalized_inputs_and_output,
157 } = free_region_relations::create(
160 Some(implicit_region_bound),
165 for u in ty::UniverseIndex::ROOT..infcx.universe() {
166 let info = UniverseInfo::other();
167 constraints.universe_causes.insert(u, info);
170 let mut borrowck_context = BorrowCheckContext {
175 constraints: &mut constraints,
179 let opaque_type_values = type_check_internal(
185 implicit_region_bound,
186 &mut borrowck_context,
188 cx.equate_inputs_and_outputs(&body, universal_regions, &normalized_inputs_and_output);
199 translate_outlives_facts(&mut cx);
200 let opaque_type_values =
201 infcx.inner.borrow_mut().opaque_type_storage.take_opaque_types();
205 .map(|(opaque_type_key, decl)| {
207 Locations::All(body.span),
208 ConstraintCategory::OpaqueType,
211 infcx.register_member_constraints(
215 decl.hidden_type.span,
217 Ok(InferOk { value: (), obligations: vec![] })
219 || "opaque_type_map".to_string(),
223 let mut hidden_type = infcx.resolve_vars_if_possible(decl.hidden_type);
225 "finalized opaque type {:?} to {:#?}",
227 hidden_type.ty.kind()
229 if hidden_type.has_infer_types_or_consts() {
230 infcx.tcx.sess.delay_span_bug(
231 decl.hidden_type.span,
232 &format!("could not resolve {:#?}", hidden_type.ty.kind()),
234 hidden_type.ty = infcx.tcx.ty_error();
237 (opaque_type_key, (hidden_type, decl.origin))
243 MirTypeckResults { constraints, universal_region_relations, opaque_type_values }
247 skip(infcx, body, promoted, region_bound_pairs, borrowck_context, extra),
250 fn type_check_internal<'a, 'tcx, R>(
251 infcx: &'a InferCtxt<'a, 'tcx>,
252 param_env: ty::ParamEnv<'tcx>,
253 body: &'a Body<'tcx>,
254 promoted: &'a IndexVec<Promoted, Body<'tcx>>,
255 region_bound_pairs: &'a RegionBoundPairs<'tcx>,
256 implicit_region_bound: ty::Region<'tcx>,
257 borrowck_context: &'a mut BorrowCheckContext<'a, 'tcx>,
258 extra: impl FnOnce(TypeChecker<'a, 'tcx>) -> R,
260 let mut checker = TypeChecker::new(
265 implicit_region_bound,
268 let errors_reported = {
269 let mut verifier = TypeVerifier::new(&mut checker, promoted);
270 verifier.visit_body(&body);
271 verifier.errors_reported
274 if !errors_reported {
275 // if verifier failed, don't do further checks to avoid ICEs
276 checker.typeck_mir(body);
282 fn translate_outlives_facts(typeck: &mut TypeChecker<'_, '_>) {
283 let cx = &mut typeck.borrowck_context;
284 if let Some(facts) = cx.all_facts {
285 let _prof_timer = typeck.infcx.tcx.prof.generic_activity("polonius_fact_generation");
286 let location_table = cx.location_table;
287 facts.subset_base.extend(cx.constraints.outlives_constraints.outlives().iter().flat_map(
288 |constraint: &OutlivesConstraint<'_>| {
289 if let Some(from_location) = constraint.locations.from_location() {
290 Either::Left(iter::once((
293 location_table.mid_index(from_location),
299 .map(move |location| (constraint.sup, constraint.sub, location)),
308 fn mirbug(tcx: TyCtxt<'_>, span: Span, msg: &str) {
309 // We sometimes see MIR failures (notably predicate failures) due to
310 // the fact that we check rvalue sized predicates here. So use `delay_span_bug`
311 // to avoid reporting bugs in those cases.
312 tcx.sess.diagnostic().delay_span_bug(span, msg);
315 enum FieldAccessError {
316 OutOfRange { field_count: usize },
319 /// Verifies that MIR types are sane to not crash further checks.
321 /// The sanitize_XYZ methods here take an MIR object and compute its
322 /// type, calling `span_mirbug` and returning an error type if there
324 struct TypeVerifier<'a, 'b, 'tcx> {
325 cx: &'a mut TypeChecker<'b, 'tcx>,
326 promoted: &'b IndexVec<Promoted, Body<'tcx>>,
328 errors_reported: bool,
331 impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
332 fn visit_span(&mut self, span: &Span) {
333 if !span.is_dummy() {
334 self.last_span = *span;
338 fn visit_place(&mut self, place: &Place<'tcx>, context: PlaceContext, location: Location) {
339 self.sanitize_place(place, location, context);
342 fn visit_constant(&mut self, constant: &Constant<'tcx>, location: Location) {
343 self.super_constant(constant, location);
344 let ty = self.sanitize_type(constant, constant.literal.ty());
346 self.cx.infcx.tcx.for_each_free_region(&ty, |live_region| {
347 let live_region_vid =
348 self.cx.borrowck_context.universal_regions.to_region_vid(live_region);
352 .liveness_constraints
353 .add_element(live_region_vid, location);
356 if let Some(annotation_index) = constant.user_ty {
357 if let Err(terr) = self.cx.relate_type_and_user_type(
358 constant.literal.ty(),
359 ty::Variance::Invariant,
360 &UserTypeProjection { base: annotation_index, projs: vec![] },
361 location.to_locations(),
362 ConstraintCategory::Boring,
364 let annotation = &self.cx.user_type_annotations[annotation_index];
368 "bad constant user type {:?} vs {:?}: {:?}",
370 constant.literal.ty(),
375 let tcx = self.tcx();
376 let maybe_uneval = match constant.literal {
377 ConstantKind::Ty(ct) => match ct.val() {
378 ty::ConstKind::Unevaluated(uv) => Some(uv),
383 if let Some(uv) = maybe_uneval {
384 if let Some(promoted) = uv.promoted {
385 let check_err = |verifier: &mut TypeVerifier<'a, 'b, 'tcx>,
386 promoted: &Body<'tcx>,
389 if let Err(terr) = verifier.cx.eq_types(
392 location.to_locations(),
393 ConstraintCategory::Boring,
398 "bad promoted type ({:?}: {:?}): {:?}",
406 if !self.errors_reported {
407 let promoted_body = &self.promoted[promoted];
408 self.sanitize_promoted(promoted_body, location);
410 let promoted_ty = promoted_body.return_ty();
411 check_err(self, promoted_body, ty, promoted_ty);
414 if let Err(terr) = self.cx.fully_perform_op(
415 location.to_locations(),
416 ConstraintCategory::Boring,
417 self.cx.param_env.and(type_op::ascribe_user_type::AscribeUserType::new(
418 constant.literal.ty(),
420 UserSubsts { substs: uv.substs, user_self_ty: None },
426 "bad constant type {:?} ({:?})",
432 } else if let Some(static_def_id) = constant.check_static_ptr(tcx) {
433 let unnormalized_ty = tcx.type_of(static_def_id);
434 let locations = location.to_locations();
435 let normalized_ty = self.cx.normalize(unnormalized_ty, locations);
436 let literal_ty = constant.literal.ty().builtin_deref(true).unwrap().ty;
438 if let Err(terr) = self.cx.eq_types(
442 ConstraintCategory::Boring,
444 span_mirbug!(self, constant, "bad static type {:?} ({:?})", constant, terr);
448 if let ty::FnDef(def_id, substs) = *constant.literal.ty().kind() {
449 let instantiated_predicates = tcx.predicates_of(def_id).instantiate(tcx, substs);
450 self.cx.normalize_and_prove_instantiated_predicates(
452 instantiated_predicates,
453 location.to_locations(),
459 fn visit_rvalue(&mut self, rvalue: &Rvalue<'tcx>, location: Location) {
460 self.super_rvalue(rvalue, location);
461 let rval_ty = rvalue.ty(self.body(), self.tcx());
462 self.sanitize_type(rvalue, rval_ty);
465 fn visit_local_decl(&mut self, local: Local, local_decl: &LocalDecl<'tcx>) {
466 self.super_local_decl(local, local_decl);
467 self.sanitize_type(local_decl, local_decl.ty);
469 if let Some(user_ty) = &local_decl.user_ty {
470 for (user_ty, span) in user_ty.projections_and_spans() {
471 let ty = if !local_decl.is_nonref_binding() {
472 // If we have a binding of the form `let ref x: T = ..`
473 // then remove the outermost reference so we can check the
474 // type annotation for the remaining type.
475 if let ty::Ref(_, rty, _) = local_decl.ty.kind() {
478 bug!("{:?} with ref binding has wrong type {}", local, local_decl.ty);
484 if let Err(terr) = self.cx.relate_type_and_user_type(
486 ty::Variance::Invariant,
488 Locations::All(*span),
489 ConstraintCategory::TypeAnnotation,
494 "bad user type on variable {:?}: {:?} != {:?} ({:?})",
505 fn visit_body(&mut self, body: &Body<'tcx>) {
506 self.sanitize_type(&"return type", body.return_ty());
507 for local_decl in &body.local_decls {
508 self.sanitize_type(local_decl, local_decl.ty);
510 if self.errors_reported {
513 self.super_body(body);
517 impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
519 cx: &'a mut TypeChecker<'b, 'tcx>,
520 promoted: &'b IndexVec<Promoted, Body<'tcx>>,
522 TypeVerifier { promoted, last_span: cx.body.span, cx, errors_reported: false }
525 fn body(&self) -> &Body<'tcx> {
529 fn tcx(&self) -> TyCtxt<'tcx> {
533 fn sanitize_type(&mut self, parent: &dyn fmt::Debug, ty: Ty<'tcx>) -> Ty<'tcx> {
534 if ty.has_escaping_bound_vars() || ty.references_error() {
535 span_mirbug_and_err!(self, parent, "bad type {:?}", ty)
541 /// Checks that the types internal to the `place` match up with
542 /// what would be expected.
547 context: PlaceContext,
549 debug!("sanitize_place: {:?}", place);
551 let mut place_ty = PlaceTy::from_ty(self.body().local_decls[place.local].ty);
553 for elem in place.projection.iter() {
554 if place_ty.variant_index.is_none() {
555 if place_ty.ty.references_error() {
556 assert!(self.errors_reported);
557 return PlaceTy::from_ty(self.tcx().ty_error());
560 place_ty = self.sanitize_projection(place_ty, elem, place, location);
563 if let PlaceContext::NonMutatingUse(NonMutatingUseContext::Copy) = context {
564 let tcx = self.tcx();
565 let trait_ref = ty::TraitRef {
566 def_id: tcx.require_lang_item(LangItem::Copy, Some(self.last_span)),
567 substs: tcx.mk_substs_trait(place_ty.ty, &[]),
570 // To have a `Copy` operand, the type `T` of the
571 // value must be `Copy`. Note that we prove that `T: Copy`,
572 // rather than using the `is_copy_modulo_regions`
573 // test. This is important because
574 // `is_copy_modulo_regions` ignores the resulting region
575 // obligations and assumes they pass. This can result in
576 // bounds from `Copy` impls being unsoundly ignored (e.g.,
577 // #29149). Note that we decide to use `Copy` before knowing
578 // whether the bounds fully apply: in effect, the rule is
579 // that if a value of some type could implement `Copy`, then
581 self.cx.prove_trait_ref(
583 location.to_locations(),
584 ConstraintCategory::CopyBound,
591 fn sanitize_promoted(&mut self, promoted_body: &'b Body<'tcx>, location: Location) {
592 // Determine the constraints from the promoted MIR by running the type
593 // checker on the promoted MIR, then transfer the constraints back to
594 // the main MIR, changing the locations to the provided location.
596 let parent_body = mem::replace(&mut self.cx.body, promoted_body);
598 // Use new sets of constraints and closure bounds so that we can
599 // modify their locations.
600 let all_facts = &mut None;
601 let mut constraints = Default::default();
602 let mut closure_bounds = Default::default();
603 let mut liveness_constraints =
604 LivenessValues::new(Rc::new(RegionValueElements::new(&promoted_body)));
605 // Don't try to add borrow_region facts for the promoted MIR
607 let mut swap_constraints = |this: &mut Self| {
608 mem::swap(this.cx.borrowck_context.all_facts, all_facts);
610 &mut this.cx.borrowck_context.constraints.outlives_constraints,
614 &mut this.cx.borrowck_context.constraints.closure_bounds_mapping,
618 &mut this.cx.borrowck_context.constraints.liveness_constraints,
619 &mut liveness_constraints,
623 swap_constraints(self);
625 self.visit_body(&promoted_body);
627 if !self.errors_reported {
628 // if verifier failed, don't do further checks to avoid ICEs
629 self.cx.typeck_mir(promoted_body);
632 self.cx.body = parent_body;
633 // Merge the outlives constraints back in, at the given location.
634 swap_constraints(self);
636 let locations = location.to_locations();
637 for constraint in constraints.outlives().iter() {
638 let mut constraint = constraint.clone();
639 constraint.locations = locations;
640 if let ConstraintCategory::Return(_)
641 | ConstraintCategory::UseAsConst
642 | ConstraintCategory::UseAsStatic = constraint.category
644 // "Returning" from a promoted is an assignment to a
645 // temporary from the user's point of view.
646 constraint.category = ConstraintCategory::Boring;
648 self.cx.borrowck_context.constraints.outlives_constraints.push(constraint)
650 for region in liveness_constraints.rows() {
651 // If the region is live at at least one location in the promoted MIR,
652 // then add a liveness constraint to the main MIR for this region
653 // at the location provided as an argument to this method
654 if liveness_constraints.get_elements(region).next().is_some() {
658 .liveness_constraints
659 .add_element(region, location);
663 if !closure_bounds.is_empty() {
664 let combined_bounds_mapping =
665 closure_bounds.into_iter().flat_map(|(_, value)| value).collect();
670 .closure_bounds_mapping
671 .insert(location, combined_bounds_mapping);
672 assert!(existing.is_none(), "Multiple promoteds/closures at the same location.");
676 fn sanitize_projection(
683 debug!("sanitize_projection: {:?} {:?} {:?}", base, pi, place);
684 let tcx = self.tcx();
685 let base_ty = base.ty;
687 ProjectionElem::Deref => {
688 let deref_ty = base_ty.builtin_deref(true);
689 PlaceTy::from_ty(deref_ty.map(|t| t.ty).unwrap_or_else(|| {
690 span_mirbug_and_err!(self, place, "deref of non-pointer {:?}", base_ty)
693 ProjectionElem::Index(i) => {
694 let index_ty = Place::from(i).ty(self.body(), tcx).ty;
695 if index_ty != tcx.types.usize {
696 PlaceTy::from_ty(span_mirbug_and_err!(self, i, "index by non-usize {:?}", i))
698 PlaceTy::from_ty(base_ty.builtin_index().unwrap_or_else(|| {
699 span_mirbug_and_err!(self, place, "index of non-array {:?}", base_ty)
703 ProjectionElem::ConstantIndex { .. } => {
704 // consider verifying in-bounds
705 PlaceTy::from_ty(base_ty.builtin_index().unwrap_or_else(|| {
706 span_mirbug_and_err!(self, place, "index of non-array {:?}", base_ty)
709 ProjectionElem::Subslice { from, to, from_end } => {
710 PlaceTy::from_ty(match base_ty.kind() {
711 ty::Array(inner, _) => {
712 assert!(!from_end, "array subslices should not use from_end");
713 tcx.mk_array(*inner, to - from)
716 assert!(from_end, "slice subslices should use from_end");
719 _ => span_mirbug_and_err!(self, place, "slice of non-array {:?}", base_ty),
722 ProjectionElem::Downcast(maybe_name, index) => match base_ty.kind() {
723 ty::Adt(adt_def, _substs) if adt_def.is_enum() => {
724 if index.as_usize() >= adt_def.variants().len() {
725 PlaceTy::from_ty(span_mirbug_and_err!(
728 "cast to variant #{:?} but enum only has {:?}",
730 adt_def.variants().len()
733 PlaceTy { ty: base_ty, variant_index: Some(index) }
736 // We do not need to handle generators here, because this runs
737 // before the generator transform stage.
739 let ty = if let Some(name) = maybe_name {
740 span_mirbug_and_err!(
743 "can't downcast {:?} as {:?}",
748 span_mirbug_and_err!(self, place, "can't downcast {:?}", base_ty)
753 ProjectionElem::Field(field, fty) => {
754 let fty = self.sanitize_type(place, fty);
755 let fty = self.cx.normalize(fty, location);
756 match self.field_ty(place, base, field, location) {
758 let ty = self.cx.normalize(ty, location);
759 if let Err(terr) = self.cx.eq_types(
762 location.to_locations(),
763 ConstraintCategory::Boring,
768 "bad field access ({:?}: {:?}): {:?}",
775 Err(FieldAccessError::OutOfRange { field_count }) => span_mirbug!(
778 "accessed field #{} but variant only has {}",
783 PlaceTy::from_ty(fty)
788 fn error(&mut self) -> Ty<'tcx> {
789 self.errors_reported = true;
790 self.tcx().ty_error()
795 parent: &dyn fmt::Debug,
796 base_ty: PlaceTy<'tcx>,
799 ) -> Result<Ty<'tcx>, FieldAccessError> {
800 let tcx = self.tcx();
802 let (variant, substs) = match base_ty {
803 PlaceTy { ty, variant_index: Some(variant_index) } => match *ty.kind() {
804 ty::Adt(adt_def, substs) => (adt_def.variant(variant_index), substs),
805 ty::Generator(def_id, substs, _) => {
806 let mut variants = substs.as_generator().state_tys(def_id, tcx);
807 let Some(mut variant) = variants.nth(variant_index.into()) else {
809 "variant_index of generator out of range: {:?}/{:?}",
811 substs.as_generator().state_tys(def_id, tcx).count()
814 return match variant.nth(field.index()) {
816 None => Err(FieldAccessError::OutOfRange { field_count: variant.count() }),
819 _ => bug!("can't have downcast of non-adt non-generator type"),
821 PlaceTy { ty, variant_index: None } => match *ty.kind() {
822 ty::Adt(adt_def, substs) if !adt_def.is_enum() => {
823 (adt_def.variant(VariantIdx::new(0)), substs)
825 ty::Closure(_, substs) => {
833 None => Err(FieldAccessError::OutOfRange {
834 field_count: substs.as_closure().upvar_tys().count(),
838 ty::Generator(_, substs, _) => {
839 // Only prefix fields (upvars and current state) are
840 // accessible without a variant index.
841 return match substs.as_generator().prefix_tys().nth(field.index()) {
843 None => Err(FieldAccessError::OutOfRange {
844 field_count: substs.as_generator().prefix_tys().count(),
849 return match tys.get(field.index()) {
851 None => Err(FieldAccessError::OutOfRange { field_count: tys.len() }),
855 return Ok(span_mirbug_and_err!(
858 "can't project out of {:?}",
865 if let Some(field) = variant.fields.get(field.index()) {
866 Ok(self.cx.normalize(field.ty(tcx, substs), location))
868 Err(FieldAccessError::OutOfRange { field_count: variant.fields.len() })
873 /// The MIR type checker. Visits the MIR and enforces all the
874 /// constraints needed for it to be valid and well-typed. Along the
875 /// way, it accrues region constraints -- these can later be used by
876 /// NLL region checking.
877 struct TypeChecker<'a, 'tcx> {
878 infcx: &'a InferCtxt<'a, 'tcx>,
879 param_env: ty::ParamEnv<'tcx>,
881 body: &'a Body<'tcx>,
882 /// User type annotations are shared between the main MIR and the MIR of
883 /// all of the promoted items.
884 user_type_annotations: &'a CanonicalUserTypeAnnotations<'tcx>,
885 region_bound_pairs: &'a RegionBoundPairs<'tcx>,
886 implicit_region_bound: ty::Region<'tcx>,
887 reported_errors: FxHashSet<(Ty<'tcx>, Span)>,
888 borrowck_context: &'a mut BorrowCheckContext<'a, 'tcx>,
891 struct BorrowCheckContext<'a, 'tcx> {
892 pub(crate) universal_regions: &'a UniversalRegions<'tcx>,
893 location_table: &'a LocationTable,
894 all_facts: &'a mut Option<AllFacts>,
895 borrow_set: &'a BorrowSet<'tcx>,
896 pub(crate) constraints: &'a mut MirTypeckRegionConstraints<'tcx>,
897 upvars: &'a [Upvar<'tcx>],
900 crate struct MirTypeckResults<'tcx> {
901 crate constraints: MirTypeckRegionConstraints<'tcx>,
902 crate universal_region_relations: Frozen<UniversalRegionRelations<'tcx>>,
903 crate opaque_type_values: VecMap<OpaqueTypeKey<'tcx>, (OpaqueHiddenType<'tcx>, OpaqueTyOrigin)>,
906 /// A collection of region constraints that must be satisfied for the
907 /// program to be considered well-typed.
908 crate struct MirTypeckRegionConstraints<'tcx> {
909 /// Maps from a `ty::Placeholder` to the corresponding
910 /// `PlaceholderIndex` bit that we will use for it.
912 /// To keep everything in sync, do not insert this set
913 /// directly. Instead, use the `placeholder_region` helper.
914 crate placeholder_indices: PlaceholderIndices,
916 /// Each time we add a placeholder to `placeholder_indices`, we
917 /// also create a corresponding "representative" region vid for
918 /// that wraps it. This vector tracks those. This way, when we
919 /// convert the same `ty::RePlaceholder(p)` twice, we can map to
920 /// the same underlying `RegionVid`.
921 crate placeholder_index_to_region: IndexVec<PlaceholderIndex, ty::Region<'tcx>>,
923 /// In general, the type-checker is not responsible for enforcing
924 /// liveness constraints; this job falls to the region inferencer,
925 /// which performs a liveness analysis. However, in some limited
926 /// cases, the MIR type-checker creates temporary regions that do
927 /// not otherwise appear in the MIR -- in particular, the
928 /// late-bound regions that it instantiates at call-sites -- and
929 /// hence it must report on their liveness constraints.
930 crate liveness_constraints: LivenessValues<RegionVid>,
932 crate outlives_constraints: OutlivesConstraintSet<'tcx>,
934 crate member_constraints: MemberConstraintSet<'tcx, RegionVid>,
936 crate closure_bounds_mapping:
937 FxHashMap<Location, FxHashMap<(RegionVid, RegionVid), (ConstraintCategory, Span)>>,
939 crate universe_causes: FxHashMap<ty::UniverseIndex, UniverseInfo<'tcx>>,
941 crate type_tests: Vec<TypeTest<'tcx>>,
944 impl<'tcx> MirTypeckRegionConstraints<'tcx> {
945 fn placeholder_region(
947 infcx: &InferCtxt<'_, 'tcx>,
948 placeholder: ty::PlaceholderRegion,
949 ) -> ty::Region<'tcx> {
950 let placeholder_index = self.placeholder_indices.insert(placeholder);
951 match self.placeholder_index_to_region.get(placeholder_index) {
954 let origin = NllRegionVariableOrigin::Placeholder(placeholder);
955 let region = infcx.next_nll_region_var_in_universe(origin, placeholder.universe);
956 self.placeholder_index_to_region.push(region);
963 /// The `Locations` type summarizes *where* region constraints are
964 /// required to hold. Normally, this is at a particular point which
965 /// created the obligation, but for constraints that the user gave, we
966 /// want the constraint to hold at all points.
967 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
969 /// Indicates that a type constraint should always be true. This
970 /// is particularly important in the new borrowck analysis for
971 /// things like the type of the return slot. Consider this
974 /// ```compile_fail,E0515
975 /// fn foo<'a>(x: &'a u32) -> &'a u32 {
977 /// return &y; // error
981 /// Here, we wind up with the signature from the return type being
982 /// something like `&'1 u32` where `'1` is a universal region. But
983 /// the type of the return slot `_0` is something like `&'2 u32`
984 /// where `'2` is an existential region variable. The type checker
985 /// requires that `&'2 u32 = &'1 u32` -- but at what point? In the
986 /// older NLL analysis, we required this only at the entry point
987 /// to the function. By the nature of the constraints, this wound
988 /// up propagating to all points reachable from start (because
989 /// `'1` -- as a universal region -- is live everywhere). In the
990 /// newer analysis, though, this doesn't work: `_0` is considered
991 /// dead at the start (it has no usable value) and hence this type
992 /// equality is basically a no-op. Then, later on, when we do `_0
993 /// = &'3 y`, that region `'3` never winds up related to the
994 /// universal region `'1` and hence no error occurs. Therefore, we
995 /// use Locations::All instead, which ensures that the `'1` and
996 /// `'2` are equal everything. We also use this for other
997 /// user-given type annotations; e.g., if the user wrote `let mut
998 /// x: &'static u32 = ...`, we would ensure that all values
999 /// assigned to `x` are of `'static` lifetime.
1001 /// The span points to the place the constraint arose. For example,
1002 /// it points to the type in a user-given type annotation. If
1003 /// there's no sensible span then it's DUMMY_SP.
1006 /// An outlives constraint that only has to hold at a single location,
1007 /// usually it represents a point where references flow from one spot to
1008 /// another (e.g., `x = y`)
1013 pub fn from_location(&self) -> Option<Location> {
1015 Locations::All(_) => None,
1016 Locations::Single(from_location) => Some(*from_location),
1020 /// Gets a span representing the location.
1021 pub fn span(&self, body: &Body<'_>) -> Span {
1023 Locations::All(span) => *span,
1024 Locations::Single(l) => body.source_info(*l).span,
1029 impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
1031 infcx: &'a InferCtxt<'a, 'tcx>,
1032 body: &'a Body<'tcx>,
1033 param_env: ty::ParamEnv<'tcx>,
1034 region_bound_pairs: &'a RegionBoundPairs<'tcx>,
1035 implicit_region_bound: ty::Region<'tcx>,
1036 borrowck_context: &'a mut BorrowCheckContext<'a, 'tcx>,
1038 let mut checker = Self {
1040 last_span: DUMMY_SP,
1042 user_type_annotations: &body.user_type_annotations,
1045 implicit_region_bound,
1047 reported_errors: Default::default(),
1049 checker.check_user_type_annotations();
1053 fn body(&self) -> &Body<'tcx> {
1057 fn unsized_feature_enabled(&self) -> bool {
1058 let features = self.tcx().features();
1059 features.unsized_locals || features.unsized_fn_params
1062 /// Equate the inferred type and the annotated type for user type annotations
1063 #[instrument(skip(self), level = "debug")]
1064 fn check_user_type_annotations(&mut self) {
1065 debug!(?self.user_type_annotations);
1066 for user_annotation in self.user_type_annotations {
1067 let CanonicalUserTypeAnnotation { span, ref user_ty, inferred_ty } = *user_annotation;
1068 let inferred_ty = self.normalize(inferred_ty, Locations::All(span));
1069 let annotation = self.instantiate_canonical_with_fresh_inference_vars(span, user_ty);
1071 UserType::Ty(mut ty) => {
1072 ty = self.normalize(ty, Locations::All(span));
1074 if let Err(terr) = self.eq_types(
1077 Locations::All(span),
1078 ConstraintCategory::BoringNoLocation,
1083 "bad user type ({:?} = {:?}): {:?}",
1090 self.prove_predicate(
1091 ty::Binder::dummy(ty::PredicateKind::WellFormed(inferred_ty.into()))
1092 .to_predicate(self.tcx()),
1093 Locations::All(span),
1094 ConstraintCategory::TypeAnnotation,
1097 UserType::TypeOf(def_id, user_substs) => {
1098 if let Err(terr) = self.fully_perform_op(
1099 Locations::All(span),
1100 ConstraintCategory::BoringNoLocation,
1101 self.param_env.and(type_op::ascribe_user_type::AscribeUserType::new(
1110 "bad user type AscribeUserType({:?}, {:?} {:?}, type_of={:?}): {:?}",
1114 self.tcx().type_of(def_id),
1123 #[instrument(skip(self, data), level = "debug")]
1124 fn push_region_constraints(
1126 locations: Locations,
1127 category: ConstraintCategory,
1128 data: &QueryRegionConstraints<'tcx>,
1130 debug!("constraints generated: {:#?}", data);
1132 constraint_conversion::ConstraintConversion::new(
1134 self.borrowck_context.universal_regions,
1135 self.region_bound_pairs,
1136 Some(self.implicit_region_bound),
1139 locations.span(self.body),
1141 &mut self.borrowck_context.constraints,
1146 /// Try to relate `sub <: sup`
1151 locations: Locations,
1152 category: ConstraintCategory,
1154 // Use this order of parameters because the sup type is usually the
1155 // "expected" type in diagnostics.
1156 self.relate_types(sup, ty::Variance::Contravariant, sub, locations, category)
1159 #[instrument(skip(self, category), level = "debug")]
1164 locations: Locations,
1165 category: ConstraintCategory,
1167 self.relate_types(expected, ty::Variance::Invariant, found, locations, category)
1170 #[instrument(skip(self), level = "debug")]
1171 fn relate_type_and_user_type(
1175 user_ty: &UserTypeProjection,
1176 locations: Locations,
1177 category: ConstraintCategory,
1179 let annotated_type = self.user_type_annotations[user_ty.base].inferred_ty;
1180 let mut curr_projected_ty = PlaceTy::from_ty(annotated_type);
1182 let tcx = self.infcx.tcx;
1184 for proj in &user_ty.projs {
1185 let projected_ty = curr_projected_ty.projection_ty_core(
1190 let ty = this.field_ty(tcx, field);
1191 self.normalize(ty, locations)
1194 curr_projected_ty = projected_ty;
1197 "user_ty base: {:?} freshened: {:?} projs: {:?} yields: {:?}",
1198 user_ty.base, annotated_type, user_ty.projs, curr_projected_ty
1201 let ty = curr_projected_ty.ty;
1202 self.relate_types(ty, v.xform(ty::Variance::Contravariant), a, locations, category)?;
1207 fn tcx(&self) -> TyCtxt<'tcx> {
1211 #[instrument(skip(self, body, location), level = "debug")]
1212 fn check_stmt(&mut self, body: &Body<'tcx>, stmt: &Statement<'tcx>, location: Location) {
1213 let tcx = self.tcx();
1215 StatementKind::Assign(box (ref place, ref rv)) => {
1216 // Assignments to temporaries are not "interesting";
1217 // they are not caused by the user, but rather artifacts
1218 // of lowering. Assignments to other sorts of places *are* interesting
1220 let category = match place.as_local() {
1221 Some(RETURN_PLACE) => {
1222 let defining_ty = &self.borrowck_context.universal_regions.defining_ty;
1223 if defining_ty.is_const() {
1224 if tcx.is_static(defining_ty.def_id()) {
1225 ConstraintCategory::UseAsStatic
1227 ConstraintCategory::UseAsConst
1230 ConstraintCategory::Return(ReturnConstraint::Normal)
1235 body.local_decls[l].local_info,
1236 Some(box LocalInfo::AggregateTemp)
1239 ConstraintCategory::Usage
1241 Some(l) if !body.local_decls[l].is_user_variable() => {
1242 ConstraintCategory::Boring
1244 _ => ConstraintCategory::Assignment,
1247 "assignment category: {:?} {:?}",
1249 place.as_local().map(|l| &body.local_decls[l])
1252 let place_ty = place.ty(body, tcx).ty;
1253 let place_ty = self.normalize(place_ty, location);
1254 let rv_ty = rv.ty(body, tcx);
1255 let rv_ty = self.normalize(rv_ty, location);
1257 self.sub_types(rv_ty, place_ty, location.to_locations(), category)
1262 "bad assignment ({:?} = {:?}): {:?}",
1269 if let Some(annotation_index) = self.rvalue_user_ty(rv) {
1270 if let Err(terr) = self.relate_type_and_user_type(
1272 ty::Variance::Invariant,
1273 &UserTypeProjection { base: annotation_index, projs: vec![] },
1274 location.to_locations(),
1275 ConstraintCategory::Boring,
1277 let annotation = &self.user_type_annotations[annotation_index];
1281 "bad user type on rvalue ({:?} = {:?}): {:?}",
1289 self.check_rvalue(body, rv, location);
1290 if !self.unsized_feature_enabled() {
1291 let trait_ref = ty::TraitRef {
1292 def_id: tcx.require_lang_item(LangItem::Sized, Some(self.last_span)),
1293 substs: tcx.mk_substs_trait(place_ty, &[]),
1295 self.prove_trait_ref(
1297 location.to_locations(),
1298 ConstraintCategory::SizedBound,
1302 StatementKind::AscribeUserType(box (ref place, ref projection), variance) => {
1303 let place_ty = place.ty(body, tcx).ty;
1304 if let Err(terr) = self.relate_type_and_user_type(
1308 Locations::All(stmt.source_info.span),
1309 ConstraintCategory::TypeAnnotation,
1311 let annotation = &self.user_type_annotations[projection.base];
1315 "bad type assert ({:?} <: {:?} with projections {:?}): {:?}",
1323 StatementKind::CopyNonOverlapping(box rustc_middle::mir::CopyNonOverlapping {
1326 stmt.source_info.span,
1327 "Unexpected StatementKind::CopyNonOverlapping, should only appear after lowering_intrinsics",
1329 StatementKind::FakeRead(..)
1330 | StatementKind::StorageLive(..)
1331 | StatementKind::StorageDead(..)
1332 | StatementKind::Retag { .. }
1333 | StatementKind::Coverage(..)
1334 | StatementKind::Nop => {}
1335 StatementKind::Deinit(..) | StatementKind::SetDiscriminant { .. } => {
1336 bug!("Statement not allowed in this MIR phase")
1341 #[instrument(skip(self, body, term_location), level = "debug")]
1342 fn check_terminator(
1345 term: &Terminator<'tcx>,
1346 term_location: Location,
1348 let tcx = self.tcx();
1350 TerminatorKind::Goto { .. }
1351 | TerminatorKind::Resume
1352 | TerminatorKind::Abort
1353 | TerminatorKind::Return
1354 | TerminatorKind::GeneratorDrop
1355 | TerminatorKind::Unreachable
1356 | TerminatorKind::Drop { .. }
1357 | TerminatorKind::FalseEdge { .. }
1358 | TerminatorKind::FalseUnwind { .. }
1359 | TerminatorKind::InlineAsm { .. } => {
1360 // no checks needed for these
1363 TerminatorKind::DropAndReplace { ref place, ref value, target: _, unwind: _ } => {
1364 let place_ty = place.ty(body, tcx).ty;
1365 let rv_ty = value.ty(body, tcx);
1367 let locations = term_location.to_locations();
1369 self.sub_types(rv_ty, place_ty, locations, ConstraintCategory::Assignment)
1374 "bad DropAndReplace ({:?} = {:?}): {:?}",
1381 TerminatorKind::SwitchInt { ref discr, switch_ty, .. } => {
1382 self.check_operand(discr, term_location);
1384 let discr_ty = discr.ty(body, tcx);
1385 if let Err(terr) = self.sub_types(
1388 term_location.to_locations(),
1389 ConstraintCategory::Assignment,
1394 "bad SwitchInt ({:?} on {:?}): {:?}",
1400 if !switch_ty.is_integral() && !switch_ty.is_char() && !switch_ty.is_bool() {
1401 span_mirbug!(self, term, "bad SwitchInt discr ty {:?}", switch_ty);
1403 // FIXME: check the values
1405 TerminatorKind::Call { ref func, ref args, ref destination, from_hir_call, .. } => {
1406 self.check_operand(func, term_location);
1408 self.check_operand(arg, term_location);
1411 let func_ty = func.ty(body, tcx);
1412 debug!("check_terminator: call, func_ty={:?}", func_ty);
1413 let sig = match func_ty.kind() {
1414 ty::FnDef(..) | ty::FnPtr(_) => func_ty.fn_sig(tcx),
1416 span_mirbug!(self, term, "call to non-function {:?}", func_ty);
1420 let (sig, map) = self.infcx.replace_bound_vars_with_fresh_vars(
1421 term.source_info.span,
1422 LateBoundRegionConversionTime::FnCall,
1425 let sig = self.normalize(sig, term_location);
1426 self.check_call_dest(body, term, &sig, destination, term_location);
1428 self.prove_predicates(
1429 sig.inputs_and_output
1431 .map(|ty| ty::Binder::dummy(ty::PredicateKind::WellFormed(ty.into()))),
1432 term_location.to_locations(),
1433 ConstraintCategory::Boring,
1436 // The ordinary liveness rules will ensure that all
1437 // regions in the type of the callee are live here. We
1438 // then further constrain the late-bound regions that
1439 // were instantiated at the call site to be live as
1440 // well. The resulting is that all the input (and
1441 // output) types in the signature must be live, since
1442 // all the inputs that fed into it were live.
1443 for &late_bound_region in map.values() {
1445 self.borrowck_context.universal_regions.to_region_vid(late_bound_region);
1446 self.borrowck_context
1448 .liveness_constraints
1449 .add_element(region_vid, term_location);
1452 self.check_call_inputs(body, term, &sig, args, term_location, from_hir_call);
1454 TerminatorKind::Assert { ref cond, ref msg, .. } => {
1455 self.check_operand(cond, term_location);
1457 let cond_ty = cond.ty(body, tcx);
1458 if cond_ty != tcx.types.bool {
1459 span_mirbug!(self, term, "bad Assert ({:?}, not bool", cond_ty);
1462 if let AssertKind::BoundsCheck { ref len, ref index } = *msg {
1463 if len.ty(body, tcx) != tcx.types.usize {
1464 span_mirbug!(self, len, "bounds-check length non-usize {:?}", len)
1466 if index.ty(body, tcx) != tcx.types.usize {
1467 span_mirbug!(self, index, "bounds-check index non-usize {:?}", index)
1471 TerminatorKind::Yield { ref value, .. } => {
1472 self.check_operand(value, term_location);
1474 let value_ty = value.ty(body, tcx);
1475 match body.yield_ty() {
1476 None => span_mirbug!(self, term, "yield in non-generator"),
1478 if let Err(terr) = self.sub_types(
1481 term_location.to_locations(),
1482 ConstraintCategory::Yield,
1487 "type of yield value is {:?}, but the yield type is {:?}: {:?}",
1502 term: &Terminator<'tcx>,
1503 sig: &ty::FnSig<'tcx>,
1504 destination: &Option<(Place<'tcx>, BasicBlock)>,
1505 term_location: Location,
1507 let tcx = self.tcx();
1508 match *destination {
1509 Some((ref dest, _target_block)) => {
1510 let dest_ty = dest.ty(body, tcx).ty;
1511 let dest_ty = self.normalize(dest_ty, term_location);
1512 let category = match dest.as_local() {
1513 Some(RETURN_PLACE) => {
1514 if let BorrowCheckContext {
1518 DefiningTy::Const(def_id, _)
1519 | DefiningTy::InlineConst(def_id, _),
1523 } = self.borrowck_context
1525 if tcx.is_static(*def_id) {
1526 ConstraintCategory::UseAsStatic
1528 ConstraintCategory::UseAsConst
1531 ConstraintCategory::Return(ReturnConstraint::Normal)
1534 Some(l) if !body.local_decls[l].is_user_variable() => {
1535 ConstraintCategory::Boring
1537 _ => ConstraintCategory::Assignment,
1540 let locations = term_location.to_locations();
1542 if let Err(terr) = self.sub_types(sig.output(), dest_ty, locations, category) {
1546 "call dest mismatch ({:?} <- {:?}): {:?}",
1553 // When `unsized_fn_params` and `unsized_locals` are both not enabled,
1554 // this check is done at `check_local`.
1555 if self.unsized_feature_enabled() {
1556 let span = term.source_info.span;
1557 self.ensure_place_sized(dest_ty, span);
1563 .conservative_is_privately_uninhabited(self.param_env.and(sig.output()))
1565 span_mirbug!(self, term, "call to converging function {:?} w/o dest", sig);
1571 fn check_call_inputs(
1574 term: &Terminator<'tcx>,
1575 sig: &ty::FnSig<'tcx>,
1576 args: &[Operand<'tcx>],
1577 term_location: Location,
1578 from_hir_call: bool,
1580 debug!("check_call_inputs({:?}, {:?})", sig, args);
1581 if args.len() < sig.inputs().len() || (args.len() > sig.inputs().len() && !sig.c_variadic) {
1582 span_mirbug!(self, term, "call to {:?} with wrong # of args", sig);
1584 for (n, (fn_arg, op_arg)) in iter::zip(sig.inputs(), args).enumerate() {
1585 let op_arg_ty = op_arg.ty(body, self.tcx());
1586 let op_arg_ty = self.normalize(op_arg_ty, term_location);
1587 let category = if from_hir_call {
1588 ConstraintCategory::CallArgument
1590 ConstraintCategory::Boring
1593 self.sub_types(op_arg_ty, *fn_arg, term_location.to_locations(), category)
1598 "bad arg #{:?} ({:?} <- {:?}): {:?}",
1608 fn check_iscleanup(&mut self, body: &Body<'tcx>, block_data: &BasicBlockData<'tcx>) {
1609 let is_cleanup = block_data.is_cleanup;
1610 self.last_span = block_data.terminator().source_info.span;
1611 match block_data.terminator().kind {
1612 TerminatorKind::Goto { target } => {
1613 self.assert_iscleanup(body, block_data, target, is_cleanup)
1615 TerminatorKind::SwitchInt { ref targets, .. } => {
1616 for target in targets.all_targets() {
1617 self.assert_iscleanup(body, block_data, *target, is_cleanup);
1620 TerminatorKind::Resume => {
1622 span_mirbug!(self, block_data, "resume on non-cleanup block!")
1625 TerminatorKind::Abort => {
1627 span_mirbug!(self, block_data, "abort on non-cleanup block!")
1630 TerminatorKind::Return => {
1632 span_mirbug!(self, block_data, "return on cleanup block")
1635 TerminatorKind::GeneratorDrop { .. } => {
1637 span_mirbug!(self, block_data, "generator_drop in cleanup block")
1640 TerminatorKind::Yield { resume, drop, .. } => {
1642 span_mirbug!(self, block_data, "yield in cleanup block")
1644 self.assert_iscleanup(body, block_data, resume, is_cleanup);
1645 if let Some(drop) = drop {
1646 self.assert_iscleanup(body, block_data, drop, is_cleanup);
1649 TerminatorKind::Unreachable => {}
1650 TerminatorKind::Drop { target, unwind, .. }
1651 | TerminatorKind::DropAndReplace { target, unwind, .. }
1652 | TerminatorKind::Assert { target, cleanup: unwind, .. } => {
1653 self.assert_iscleanup(body, block_data, target, is_cleanup);
1654 if let Some(unwind) = unwind {
1656 span_mirbug!(self, block_data, "unwind on cleanup block")
1658 self.assert_iscleanup(body, block_data, unwind, true);
1661 TerminatorKind::Call { ref destination, cleanup, .. } => {
1662 if let &Some((_, target)) = destination {
1663 self.assert_iscleanup(body, block_data, target, is_cleanup);
1665 if let Some(cleanup) = cleanup {
1667 span_mirbug!(self, block_data, "cleanup on cleanup block")
1669 self.assert_iscleanup(body, block_data, cleanup, true);
1672 TerminatorKind::FalseEdge { real_target, imaginary_target } => {
1673 self.assert_iscleanup(body, block_data, real_target, is_cleanup);
1674 self.assert_iscleanup(body, block_data, imaginary_target, is_cleanup);
1676 TerminatorKind::FalseUnwind { real_target, unwind } => {
1677 self.assert_iscleanup(body, block_data, real_target, is_cleanup);
1678 if let Some(unwind) = unwind {
1680 span_mirbug!(self, block_data, "cleanup in cleanup block via false unwind");
1682 self.assert_iscleanup(body, block_data, unwind, true);
1685 TerminatorKind::InlineAsm { destination, cleanup, .. } => {
1686 if let Some(target) = destination {
1687 self.assert_iscleanup(body, block_data, target, is_cleanup);
1689 if let Some(cleanup) = cleanup {
1691 span_mirbug!(self, block_data, "cleanup on cleanup block")
1693 self.assert_iscleanup(body, block_data, cleanup, true);
1699 fn assert_iscleanup(
1702 ctxt: &dyn fmt::Debug,
1706 if body[bb].is_cleanup != iscleanuppad {
1707 span_mirbug!(self, ctxt, "cleanuppad mismatch: {:?} should be {:?}", bb, iscleanuppad);
1711 fn check_local(&mut self, body: &Body<'tcx>, local: Local, local_decl: &LocalDecl<'tcx>) {
1712 match body.local_kind(local) {
1713 LocalKind::ReturnPointer | LocalKind::Arg => {
1714 // return values of normal functions are required to be
1715 // sized by typeck, but return values of ADT constructors are
1716 // not because we don't include a `Self: Sized` bounds on them.
1718 // Unbound parts of arguments were never required to be Sized
1719 // - maybe we should make that a warning.
1722 LocalKind::Var | LocalKind::Temp => {}
1725 // When `unsized_fn_params` or `unsized_locals` is enabled, only function calls
1726 // and nullary ops are checked in `check_call_dest`.
1727 if !self.unsized_feature_enabled() {
1728 let span = local_decl.source_info.span;
1729 let ty = local_decl.ty;
1730 self.ensure_place_sized(ty, span);
1734 fn ensure_place_sized(&mut self, ty: Ty<'tcx>, span: Span) {
1735 let tcx = self.tcx();
1737 // Erase the regions from `ty` to get a global type. The
1738 // `Sized` bound in no way depends on precise regions, so this
1739 // shouldn't affect `is_sized`.
1740 let erased_ty = tcx.erase_regions(ty);
1741 if !erased_ty.is_sized(tcx.at(span), self.param_env) {
1742 // in current MIR construction, all non-control-flow rvalue
1743 // expressions evaluate through `as_temp` or `into` a return
1744 // slot or local, so to find all unsized rvalues it is enough
1745 // to check all temps, return slots and locals.
1746 if self.reported_errors.replace((ty, span)).is_none() {
1747 let mut diag = struct_span_err!(
1751 "cannot move a value of type {0}: the size of {0} \
1752 cannot be statically determined",
1756 // While this is located in `nll::typeck` this error is not
1757 // an NLL error, it's a required check to prevent creation
1758 // of unsized rvalues in a call expression.
1764 fn aggregate_field_ty(
1766 ak: &AggregateKind<'tcx>,
1769 ) -> Result<Ty<'tcx>, FieldAccessError> {
1770 let tcx = self.tcx();
1773 AggregateKind::Adt(adt_did, variant_index, substs, _, active_field_index) => {
1774 let def = tcx.adt_def(adt_did);
1775 let variant = &def.variant(variant_index);
1776 let adj_field_index = active_field_index.unwrap_or(field_index);
1777 if let Some(field) = variant.fields.get(adj_field_index) {
1778 Ok(self.normalize(field.ty(tcx, substs), location))
1780 Err(FieldAccessError::OutOfRange { field_count: variant.fields.len() })
1783 AggregateKind::Closure(_, substs) => {
1784 match substs.as_closure().upvar_tys().nth(field_index) {
1786 None => Err(FieldAccessError::OutOfRange {
1787 field_count: substs.as_closure().upvar_tys().count(),
1791 AggregateKind::Generator(_, substs, _) => {
1792 // It doesn't make sense to look at a field beyond the prefix;
1793 // these require a variant index, and are not initialized in
1794 // aggregate rvalues.
1795 match substs.as_generator().prefix_tys().nth(field_index) {
1797 None => Err(FieldAccessError::OutOfRange {
1798 field_count: substs.as_generator().prefix_tys().count(),
1802 AggregateKind::Array(ty) => Ok(ty),
1803 AggregateKind::Tuple => {
1804 unreachable!("This should have been covered in check_rvalues");
1809 fn check_operand(&mut self, op: &Operand<'tcx>, location: Location) {
1810 if let Operand::Constant(constant) = op {
1811 let maybe_uneval = match constant.literal {
1812 ConstantKind::Ty(ct) => match ct.val() {
1813 ty::ConstKind::Unevaluated(uv) => Some(uv),
1818 if let Some(uv) = maybe_uneval {
1819 if uv.promoted.is_none() {
1820 let tcx = self.tcx();
1821 let def_id = uv.def.def_id_for_type_of();
1822 if tcx.def_kind(def_id) == DefKind::InlineConst {
1823 let predicates = self.prove_closure_bounds(
1825 def_id.expect_local(),
1829 self.normalize_and_prove_instantiated_predicates(
1832 location.to_locations(),
1840 fn check_rvalue(&mut self, body: &Body<'tcx>, rvalue: &Rvalue<'tcx>, location: Location) {
1841 let tcx = self.tcx();
1844 Rvalue::Aggregate(ak, ops) => {
1846 self.check_operand(op, location);
1848 self.check_aggregate_rvalue(&body, rvalue, ak, ops, location)
1851 Rvalue::Repeat(operand, len) => {
1852 self.check_operand(operand, location);
1854 // If the length cannot be evaluated we must assume that the length can be larger
1856 // If the length is larger than 1, the repeat expression will need to copy the
1857 // element, so we require the `Copy` trait.
1858 if len.try_eval_usize(tcx, self.param_env).map_or(true, |len| len > 1) {
1860 Operand::Copy(..) | Operand::Constant(..) => {
1861 // These are always okay: direct use of a const, or a value that can evidently be copied.
1863 Operand::Move(place) => {
1864 // Make sure that repeated elements implement `Copy`.
1865 let span = body.source_info(location).span;
1866 let ty = place.ty(body, tcx).ty;
1867 let trait_ref = ty::TraitRef::new(
1868 tcx.require_lang_item(LangItem::Copy, Some(span)),
1869 tcx.mk_substs_trait(ty, &[]),
1872 self.prove_trait_ref(
1874 Locations::Single(location),
1875 ConstraintCategory::CopyBound,
1882 &Rvalue::NullaryOp(_, ty) => {
1883 let trait_ref = ty::TraitRef {
1884 def_id: tcx.require_lang_item(LangItem::Sized, Some(self.last_span)),
1885 substs: tcx.mk_substs_trait(ty, &[]),
1888 self.prove_trait_ref(
1890 location.to_locations(),
1891 ConstraintCategory::SizedBound,
1895 Rvalue::ShallowInitBox(operand, ty) => {
1896 self.check_operand(operand, location);
1898 let trait_ref = ty::TraitRef {
1899 def_id: tcx.require_lang_item(LangItem::Sized, Some(self.last_span)),
1900 substs: tcx.mk_substs_trait(*ty, &[]),
1903 self.prove_trait_ref(
1905 location.to_locations(),
1906 ConstraintCategory::SizedBound,
1910 Rvalue::Cast(cast_kind, op, ty) => {
1911 self.check_operand(op, location);
1914 CastKind::Pointer(PointerCast::ReifyFnPointer) => {
1915 let fn_sig = op.ty(body, tcx).fn_sig(tcx);
1917 // The type that we see in the fcx is like
1918 // `foo::<'a, 'b>`, where `foo` is the path to a
1919 // function definition. When we extract the
1920 // signature, it comes from the `fn_sig` query,
1921 // and hence may contain unnormalized results.
1922 let fn_sig = self.normalize(fn_sig, location);
1924 let ty_fn_ptr_from = tcx.mk_fn_ptr(fn_sig);
1926 if let Err(terr) = self.eq_types(
1929 location.to_locations(),
1930 ConstraintCategory::Cast,
1935 "equating {:?} with {:?} yields {:?}",
1943 CastKind::Pointer(PointerCast::ClosureFnPointer(unsafety)) => {
1944 let sig = match op.ty(body, tcx).kind() {
1945 ty::Closure(_, substs) => substs.as_closure().sig(),
1948 let ty_fn_ptr_from = tcx.mk_fn_ptr(tcx.signature_unclosure(sig, *unsafety));
1950 if let Err(terr) = self.eq_types(
1953 location.to_locations(),
1954 ConstraintCategory::Cast,
1959 "equating {:?} with {:?} yields {:?}",
1967 CastKind::Pointer(PointerCast::UnsafeFnPointer) => {
1968 let fn_sig = op.ty(body, tcx).fn_sig(tcx);
1970 // The type that we see in the fcx is like
1971 // `foo::<'a, 'b>`, where `foo` is the path to a
1972 // function definition. When we extract the
1973 // signature, it comes from the `fn_sig` query,
1974 // and hence may contain unnormalized results.
1975 let fn_sig = self.normalize(fn_sig, location);
1977 let ty_fn_ptr_from = tcx.safe_to_unsafe_fn_ty(fn_sig);
1979 if let Err(terr) = self.eq_types(
1982 location.to_locations(),
1983 ConstraintCategory::Cast,
1988 "equating {:?} with {:?} yields {:?}",
1996 CastKind::Pointer(PointerCast::Unsize) => {
1998 let trait_ref = ty::TraitRef {
2000 .require_lang_item(LangItem::CoerceUnsized, Some(self.last_span)),
2001 substs: tcx.mk_substs_trait(op.ty(body, tcx), &[ty.into()]),
2004 self.prove_trait_ref(
2006 location.to_locations(),
2007 ConstraintCategory::Cast,
2011 CastKind::Pointer(PointerCast::MutToConstPointer) => {
2012 let ty::RawPtr(ty::TypeAndMut {
2014 mutbl: hir::Mutability::Mut,
2015 }) = op.ty(body, tcx).kind() else {
2019 "unexpected base type for cast {:?}",
2024 let ty::RawPtr(ty::TypeAndMut {
2026 mutbl: hir::Mutability::Not,
2027 }) = ty.kind() else {
2031 "unexpected target type for cast {:?}",
2036 if let Err(terr) = self.sub_types(
2039 location.to_locations(),
2040 ConstraintCategory::Cast,
2045 "relating {:?} with {:?} yields {:?}",
2053 CastKind::Pointer(PointerCast::ArrayToPointer) => {
2054 let ty_from = op.ty(body, tcx);
2056 let opt_ty_elem_mut = match ty_from.kind() {
2057 ty::RawPtr(ty::TypeAndMut { mutbl: array_mut, ty: array_ty }) => {
2058 match array_ty.kind() {
2059 ty::Array(ty_elem, _) => Some((ty_elem, *array_mut)),
2066 let Some((ty_elem, ty_mut)) = opt_ty_elem_mut else {
2070 "ArrayToPointer cast from unexpected type {:?}",
2076 let (ty_to, ty_to_mut) = match ty.kind() {
2077 ty::RawPtr(ty::TypeAndMut { mutbl: ty_to_mut, ty: ty_to }) => {
2084 "ArrayToPointer cast to unexpected type {:?}",
2091 if ty_to_mut == Mutability::Mut && ty_mut == Mutability::Not {
2095 "ArrayToPointer cast from const {:?} to mut {:?}",
2102 if let Err(terr) = self.sub_types(
2105 location.to_locations(),
2106 ConstraintCategory::Cast,
2111 "relating {:?} with {:?} yields {:?}",
2120 let ty_from = op.ty(body, tcx);
2121 let cast_ty_from = CastTy::from_ty(ty_from);
2122 let cast_ty_to = CastTy::from_ty(*ty);
2123 match (cast_ty_from, cast_ty_to) {
2125 | (_, None | Some(CastTy::FnPtr))
2126 | (Some(CastTy::Float), Some(CastTy::Ptr(_)))
2127 | (Some(CastTy::Ptr(_) | CastTy::FnPtr), Some(CastTy::Float)) => {
2128 span_mirbug!(self, rvalue, "Invalid cast {:?} -> {:?}", ty_from, ty,)
2131 Some(CastTy::Int(_)),
2132 Some(CastTy::Int(_) | CastTy::Float | CastTy::Ptr(_)),
2134 | (Some(CastTy::Float), Some(CastTy::Int(_) | CastTy::Float))
2135 | (Some(CastTy::Ptr(_)), Some(CastTy::Int(_) | CastTy::Ptr(_)))
2136 | (Some(CastTy::FnPtr), Some(CastTy::Int(_) | CastTy::Ptr(_))) => (),
2142 Rvalue::Ref(region, _borrow_kind, borrowed_place) => {
2143 self.add_reborrow_constraint(&body, location, *region, borrowed_place);
2147 BinOp::Eq | BinOp::Ne | BinOp::Lt | BinOp::Le | BinOp::Gt | BinOp::Ge,
2150 self.check_operand(left, location);
2151 self.check_operand(right, location);
2153 let ty_left = left.ty(body, tcx);
2154 match ty_left.kind() {
2155 // Types with regions are comparable if they have a common super-type.
2156 ty::RawPtr(_) | ty::FnPtr(_) => {
2157 let ty_right = right.ty(body, tcx);
2158 let common_ty = self.infcx.next_ty_var(TypeVariableOrigin {
2159 kind: TypeVariableOriginKind::MiscVariable,
2160 span: body.source_info(location).span,
2165 location.to_locations(),
2166 ConstraintCategory::Boring,
2168 .unwrap_or_else(|err| {
2169 bug!("Could not equate type variable with {:?}: {:?}", ty_left, err)
2171 if let Err(terr) = self.sub_types(
2174 location.to_locations(),
2175 ConstraintCategory::Boring,
2180 "unexpected comparison types {:?} and {:?} yields {:?}",
2187 // For types with no regions we can just check that the
2188 // both operands have the same type.
2189 ty::Int(_) | ty::Uint(_) | ty::Bool | ty::Char | ty::Float(_)
2190 if ty_left == right.ty(body, tcx) => {}
2191 // Other types are compared by trait methods, not by
2192 // `Rvalue::BinaryOp`.
2196 "unexpected comparison types {:?} and {:?}",
2203 Rvalue::Use(operand) | Rvalue::UnaryOp(_, operand) => {
2204 self.check_operand(operand, location);
2207 Rvalue::BinaryOp(_, box (left, right))
2208 | Rvalue::CheckedBinaryOp(_, box (left, right)) => {
2209 self.check_operand(left, location);
2210 self.check_operand(right, location);
2213 Rvalue::AddressOf(..)
2214 | Rvalue::ThreadLocalRef(..)
2216 | Rvalue::Discriminant(..) => {}
2220 /// If this rvalue supports a user-given type annotation, then
2221 /// extract and return it. This represents the final type of the
2222 /// rvalue and will be unified with the inferred type.
2223 fn rvalue_user_ty(&self, rvalue: &Rvalue<'tcx>) -> Option<UserTypeAnnotationIndex> {
2226 | Rvalue::ThreadLocalRef(_)
2227 | Rvalue::Repeat(..)
2229 | Rvalue::AddressOf(..)
2232 | Rvalue::ShallowInitBox(..)
2233 | Rvalue::BinaryOp(..)
2234 | Rvalue::CheckedBinaryOp(..)
2235 | Rvalue::NullaryOp(..)
2236 | Rvalue::UnaryOp(..)
2237 | Rvalue::Discriminant(..) => None,
2239 Rvalue::Aggregate(aggregate, _) => match **aggregate {
2240 AggregateKind::Adt(_, _, _, user_ty, _) => user_ty,
2241 AggregateKind::Array(_) => None,
2242 AggregateKind::Tuple => None,
2243 AggregateKind::Closure(_, _) => None,
2244 AggregateKind::Generator(_, _, _) => None,
2249 fn check_aggregate_rvalue(
2252 rvalue: &Rvalue<'tcx>,
2253 aggregate_kind: &AggregateKind<'tcx>,
2254 operands: &[Operand<'tcx>],
2257 let tcx = self.tcx();
2259 self.prove_aggregate_predicates(aggregate_kind, location);
2261 if *aggregate_kind == AggregateKind::Tuple {
2262 // tuple rvalue field type is always the type of the op. Nothing to check here.
2266 for (i, operand) in operands.iter().enumerate() {
2267 let field_ty = match self.aggregate_field_ty(aggregate_kind, i, location) {
2268 Ok(field_ty) => field_ty,
2269 Err(FieldAccessError::OutOfRange { field_count }) => {
2273 "accessed field #{} but variant only has {}",
2280 let operand_ty = operand.ty(body, tcx);
2281 let operand_ty = self.normalize(operand_ty, location);
2283 if let Err(terr) = self.sub_types(
2286 location.to_locations(),
2287 ConstraintCategory::Boring,
2292 "{:?} is not a subtype of {:?}: {:?}",
2301 /// Adds the constraints that arise from a borrow expression `&'a P` at the location `L`.
2305 /// - `location`: the location `L` where the borrow expression occurs
2306 /// - `borrow_region`: the region `'a` associated with the borrow
2307 /// - `borrowed_place`: the place `P` being borrowed
2308 fn add_reborrow_constraint(
2312 borrow_region: ty::Region<'tcx>,
2313 borrowed_place: &Place<'tcx>,
2315 // These constraints are only meaningful during borrowck:
2316 let BorrowCheckContext { borrow_set, location_table, all_facts, constraints, .. } =
2317 self.borrowck_context;
2319 // In Polonius mode, we also push a `loan_issued_at` fact
2320 // linking the loan to the region (in some cases, though,
2321 // there is no loan associated with this borrow expression --
2322 // that occurs when we are borrowing an unsafe place, for
2324 if let Some(all_facts) = all_facts {
2325 let _prof_timer = self.infcx.tcx.prof.generic_activity("polonius_fact_generation");
2326 if let Some(borrow_index) = borrow_set.get_index_of(&location) {
2327 let region_vid = borrow_region.to_region_vid();
2328 all_facts.loan_issued_at.push((
2331 location_table.mid_index(location),
2336 // If we are reborrowing the referent of another reference, we
2337 // need to add outlives relationships. In a case like `&mut
2338 // *p`, where the `p` has type `&'b mut Foo`, for example, we
2339 // need to ensure that `'b: 'a`.
2342 "add_reborrow_constraint({:?}, {:?}, {:?})",
2343 location, borrow_region, borrowed_place
2346 let mut cursor = borrowed_place.projection.as_ref();
2347 let tcx = self.infcx.tcx;
2348 let field = path_utils::is_upvar_field_projection(
2350 &self.borrowck_context.upvars,
2351 borrowed_place.as_ref(),
2354 let category = if let Some(field) = field {
2355 ConstraintCategory::ClosureUpvar(field)
2357 ConstraintCategory::Boring
2360 while let [proj_base @ .., elem] = cursor {
2363 debug!("add_reborrow_constraint - iteration {:?}", elem);
2366 ProjectionElem::Deref => {
2367 let base_ty = Place::ty_from(borrowed_place.local, proj_base, body, tcx).ty;
2369 debug!("add_reborrow_constraint - base_ty = {:?}", base_ty);
2370 match base_ty.kind() {
2371 ty::Ref(ref_region, _, mutbl) => {
2372 constraints.outlives_constraints.push(OutlivesConstraint {
2373 sup: ref_region.to_region_vid(),
2374 sub: borrow_region.to_region_vid(),
2375 locations: location.to_locations(),
2376 span: location.to_locations().span(body),
2378 variance_info: ty::VarianceDiagInfo::default(),
2382 hir::Mutability::Not => {
2383 // Immutable reference. We don't need the base
2384 // to be valid for the entire lifetime of
2388 hir::Mutability::Mut => {
2389 // Mutable reference. We *do* need the base
2390 // to be valid, because after the base becomes
2391 // invalid, someone else can use our mutable deref.
2393 // This is in order to make the following function
2396 // fn unsafe_deref<'a, 'b>(x: &'a &'b mut T) -> &'b mut T {
2401 // As otherwise you could clone `&mut T` using the
2402 // following function:
2404 // fn bad(x: &mut T) -> (&mut T, &mut T) {
2405 // let my_clone = unsafe_deref(&'a x);
2414 // deref of raw pointer, guaranteed to be valid
2417 ty::Adt(def, _) if def.is_box() => {
2418 // deref of `Box`, need the base to be valid - propagate
2420 _ => bug!("unexpected deref ty {:?} in {:?}", base_ty, borrowed_place),
2423 ProjectionElem::Field(..)
2424 | ProjectionElem::Downcast(..)
2425 | ProjectionElem::Index(..)
2426 | ProjectionElem::ConstantIndex { .. }
2427 | ProjectionElem::Subslice { .. } => {
2428 // other field access
2434 fn prove_aggregate_predicates(
2436 aggregate_kind: &AggregateKind<'tcx>,
2439 let tcx = self.tcx();
2442 "prove_aggregate_predicates(aggregate_kind={:?}, location={:?})",
2443 aggregate_kind, location
2446 let (def_id, instantiated_predicates) = match aggregate_kind {
2447 AggregateKind::Adt(adt_did, _, substs, _, _) => {
2448 (*adt_did, tcx.predicates_of(*adt_did).instantiate(tcx, substs))
2451 // For closures, we have some **extra requirements** we
2453 // have to check. In particular, in their upvars and
2454 // signatures, closures often reference various regions
2455 // from the surrounding function -- we call those the
2456 // closure's free regions. When we borrow-check (and hence
2457 // region-check) closures, we may find that the closure
2458 // requires certain relationships between those free
2459 // regions. However, because those free regions refer to
2460 // portions of the CFG of their caller, the closure is not
2461 // in a position to verify those relationships. In that
2462 // case, the requirements get "propagated" to us, and so
2463 // we have to solve them here where we instantiate the
2466 // Despite the opacity of the previous paragraph, this is
2467 // actually relatively easy to understand in terms of the
2468 // desugaring. A closure gets desugared to a struct, and
2469 // these extra requirements are basically like where
2470 // clauses on the struct.
2471 AggregateKind::Closure(def_id, substs)
2472 | AggregateKind::Generator(def_id, substs, _) => {
2473 (*def_id, self.prove_closure_bounds(tcx, def_id.expect_local(), substs, location))
2476 AggregateKind::Array(_) | AggregateKind::Tuple => {
2477 (CRATE_DEF_ID.to_def_id(), ty::InstantiatedPredicates::empty())
2481 self.normalize_and_prove_instantiated_predicates(
2483 instantiated_predicates,
2484 location.to_locations(),
2488 fn prove_closure_bounds(
2492 substs: SubstsRef<'tcx>,
2494 ) -> ty::InstantiatedPredicates<'tcx> {
2495 if let Some(ref closure_region_requirements) = tcx.mir_borrowck(def_id).closure_requirements
2497 let closure_constraints = QueryRegionConstraints {
2498 outlives: closure_region_requirements.apply_requirements(
2504 // Presently, closures never propagate member
2505 // constraints to their parents -- they are enforced
2506 // locally. This is largely a non-issue as member
2507 // constraints only come from `-> impl Trait` and
2508 // friends which don't appear (thus far...) in
2510 member_constraints: vec![],
2513 let bounds_mapping = closure_constraints
2517 .filter_map(|(idx, constraint)| {
2518 let ty::OutlivesPredicate(k1, r2) =
2519 constraint.no_bound_vars().unwrap_or_else(|| {
2520 bug!("query_constraint {:?} contained bound vars", constraint,);
2524 GenericArgKind::Lifetime(r1) => {
2525 // constraint is r1: r2
2526 let r1_vid = self.borrowck_context.universal_regions.to_region_vid(r1);
2527 let r2_vid = self.borrowck_context.universal_regions.to_region_vid(r2);
2528 let outlives_requirements =
2529 &closure_region_requirements.outlives_requirements[idx];
2532 (outlives_requirements.category, outlives_requirements.blame_span),
2535 GenericArgKind::Type(_) | GenericArgKind::Const(_) => None,
2543 .closure_bounds_mapping
2544 .insert(location, bounds_mapping);
2545 assert!(existing.is_none(), "Multiple closures at the same location.");
2547 self.push_region_constraints(
2548 location.to_locations(),
2549 ConstraintCategory::ClosureBounds,
2550 &closure_constraints,
2554 tcx.predicates_of(def_id).instantiate(tcx, substs)
2557 #[instrument(skip(self, body), level = "debug")]
2558 fn typeck_mir(&mut self, body: &Body<'tcx>) {
2559 self.last_span = body.span;
2562 for (local, local_decl) in body.local_decls.iter_enumerated() {
2563 self.check_local(&body, local, local_decl);
2566 for (block, block_data) in body.basic_blocks().iter_enumerated() {
2567 let mut location = Location { block, statement_index: 0 };
2568 for stmt in &block_data.statements {
2569 if !stmt.source_info.span.is_dummy() {
2570 self.last_span = stmt.source_info.span;
2572 self.check_stmt(body, stmt, location);
2573 location.statement_index += 1;
2576 self.check_terminator(&body, block_data.terminator(), location);
2577 self.check_iscleanup(&body, block_data);
2582 trait NormalizeLocation: fmt::Debug + Copy {
2583 fn to_locations(self) -> Locations;
2586 impl NormalizeLocation for Locations {
2587 fn to_locations(self) -> Locations {
2592 impl NormalizeLocation for Location {
2593 fn to_locations(self) -> Locations {
2594 Locations::Single(self)
2598 /// Runs `infcx.instantiate_opaque_types`. Unlike other `TypeOp`s,
2599 /// this is not canonicalized - it directly affects the main `InferCtxt`
2600 /// that we use during MIR borrowchecking.
2602 pub(super) struct InstantiateOpaqueType<'tcx> {
2603 pub base_universe: Option<ty::UniverseIndex>,
2604 pub region_constraints: Option<RegionConstraintData<'tcx>>,
2605 pub obligations: Vec<PredicateObligation<'tcx>>,
2608 impl<'tcx> TypeOp<'tcx> for InstantiateOpaqueType<'tcx> {
2610 /// We use this type itself to store the information used
2611 /// when reporting errors. Since this is not a query, we don't
2612 /// re-run anything during error reporting - we just use the information
2613 /// we saved to help extract an error from the already-existing region
2614 /// constraints in our `InferCtxt`
2615 type ErrorInfo = InstantiateOpaqueType<'tcx>;
2617 fn fully_perform(mut self, infcx: &InferCtxt<'_, 'tcx>) -> Fallible<TypeOpOutput<'tcx, Self>> {
2618 let (mut output, region_constraints) = scrape_region_constraints(infcx, || {
2619 Ok(InferOk { value: (), obligations: self.obligations.clone() })
2621 self.region_constraints = Some(region_constraints);
2622 output.error_info = Some(self);