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;
97 pub(crate) mod liveness;
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 debug!(?normalized_inputs_and_output);
167 for u in ty::UniverseIndex::ROOT..infcx.universe() {
168 let info = UniverseInfo::other();
169 constraints.universe_causes.insert(u, info);
172 let mut borrowck_context = BorrowCheckContext {
177 constraints: &mut constraints,
181 let opaque_type_values = type_check_internal(
187 implicit_region_bound,
188 &mut borrowck_context,
190 debug!("inside extra closure of type_check_internal");
191 cx.equate_inputs_and_outputs(&body, universal_regions, &normalized_inputs_and_output);
202 translate_outlives_facts(&mut cx);
203 let opaque_type_values =
204 infcx.inner.borrow_mut().opaque_type_storage.take_opaque_types();
208 .map(|(opaque_type_key, decl)| {
210 Locations::All(body.span),
211 ConstraintCategory::OpaqueType,
214 infcx.register_member_constraints(
218 decl.hidden_type.span,
220 Ok(InferOk { value: (), obligations: vec![] })
222 || "opaque_type_map".to_string(),
226 let mut hidden_type = infcx.resolve_vars_if_possible(decl.hidden_type);
228 "finalized opaque type {:?} to {:#?}",
230 hidden_type.ty.kind()
232 if hidden_type.has_infer_types_or_consts() {
233 infcx.tcx.sess.delay_span_bug(
234 decl.hidden_type.span,
235 &format!("could not resolve {:#?}", hidden_type.ty.kind()),
237 hidden_type.ty = infcx.tcx.ty_error();
240 (opaque_type_key, (hidden_type, decl.origin))
246 MirTypeckResults { constraints, universal_region_relations, opaque_type_values }
250 skip(infcx, body, promoted, region_bound_pairs, borrowck_context, extra),
253 fn type_check_internal<'a, 'tcx, R>(
254 infcx: &'a InferCtxt<'a, 'tcx>,
255 param_env: ty::ParamEnv<'tcx>,
256 body: &'a Body<'tcx>,
257 promoted: &'a IndexVec<Promoted, Body<'tcx>>,
258 region_bound_pairs: &'a RegionBoundPairs<'tcx>,
259 implicit_region_bound: ty::Region<'tcx>,
260 borrowck_context: &'a mut BorrowCheckContext<'a, 'tcx>,
261 extra: impl FnOnce(TypeChecker<'a, 'tcx>) -> R,
263 debug!("body: {:#?}", body);
264 let mut checker = TypeChecker::new(
269 implicit_region_bound,
272 let errors_reported = {
273 let mut verifier = TypeVerifier::new(&mut checker, promoted);
274 verifier.visit_body(&body);
275 verifier.errors_reported
278 if !errors_reported {
279 // if verifier failed, don't do further checks to avoid ICEs
280 checker.typeck_mir(body);
286 fn translate_outlives_facts(typeck: &mut TypeChecker<'_, '_>) {
287 let cx = &mut typeck.borrowck_context;
288 if let Some(facts) = cx.all_facts {
289 let _prof_timer = typeck.infcx.tcx.prof.generic_activity("polonius_fact_generation");
290 let location_table = cx.location_table;
291 facts.subset_base.extend(cx.constraints.outlives_constraints.outlives().iter().flat_map(
292 |constraint: &OutlivesConstraint<'_>| {
293 if let Some(from_location) = constraint.locations.from_location() {
294 Either::Left(iter::once((
297 location_table.mid_index(from_location),
303 .map(move |location| (constraint.sup, constraint.sub, location)),
312 fn mirbug(tcx: TyCtxt<'_>, span: Span, msg: &str) {
313 // We sometimes see MIR failures (notably predicate failures) due to
314 // the fact that we check rvalue sized predicates here. So use `delay_span_bug`
315 // to avoid reporting bugs in those cases.
316 tcx.sess.diagnostic().delay_span_bug(span, msg);
319 enum FieldAccessError {
320 OutOfRange { field_count: usize },
323 /// Verifies that MIR types are sane to not crash further checks.
325 /// The sanitize_XYZ methods here take an MIR object and compute its
326 /// type, calling `span_mirbug` and returning an error type if there
328 struct TypeVerifier<'a, 'b, 'tcx> {
329 cx: &'a mut TypeChecker<'b, 'tcx>,
330 promoted: &'b IndexVec<Promoted, Body<'tcx>>,
332 errors_reported: bool,
335 impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
336 fn visit_span(&mut self, span: &Span) {
337 if !span.is_dummy() {
338 self.last_span = *span;
342 fn visit_place(&mut self, place: &Place<'tcx>, context: PlaceContext, location: Location) {
343 self.sanitize_place(place, location, context);
346 fn visit_constant(&mut self, constant: &Constant<'tcx>, location: Location) {
347 self.super_constant(constant, location);
348 let ty = self.sanitize_type(constant, constant.literal.ty());
350 self.cx.infcx.tcx.for_each_free_region(&ty, |live_region| {
351 let live_region_vid =
352 self.cx.borrowck_context.universal_regions.to_region_vid(live_region);
356 .liveness_constraints
357 .add_element(live_region_vid, location);
360 if let Some(annotation_index) = constant.user_ty {
361 if let Err(terr) = self.cx.relate_type_and_user_type(
362 constant.literal.ty(),
363 ty::Variance::Invariant,
364 &UserTypeProjection { base: annotation_index, projs: vec![] },
365 location.to_locations(),
366 ConstraintCategory::Boring,
368 let annotation = &self.cx.user_type_annotations[annotation_index];
372 "bad constant user type {:?} vs {:?}: {:?}",
374 constant.literal.ty(),
379 let tcx = self.tcx();
380 let maybe_uneval = match constant.literal {
381 ConstantKind::Ty(ct) => match ct.val() {
382 ty::ConstKind::Unevaluated(uv) => Some(uv),
387 if let Some(uv) = maybe_uneval {
388 if let Some(promoted) = uv.promoted {
389 let check_err = |verifier: &mut TypeVerifier<'a, 'b, 'tcx>,
390 promoted: &Body<'tcx>,
393 if let Err(terr) = verifier.cx.eq_types(
396 location.to_locations(),
397 ConstraintCategory::Boring,
402 "bad promoted type ({:?}: {:?}): {:?}",
410 if !self.errors_reported {
411 let promoted_body = &self.promoted[promoted];
412 self.sanitize_promoted(promoted_body, location);
414 let promoted_ty = promoted_body.return_ty();
415 check_err(self, promoted_body, ty, promoted_ty);
418 if let Err(terr) = self.cx.fully_perform_op(
419 location.to_locations(),
420 ConstraintCategory::Boring,
421 self.cx.param_env.and(type_op::ascribe_user_type::AscribeUserType::new(
422 constant.literal.ty(),
424 UserSubsts { substs: uv.substs, user_self_ty: None },
430 "bad constant type {:?} ({:?})",
436 } else if let Some(static_def_id) = constant.check_static_ptr(tcx) {
437 let unnormalized_ty = tcx.type_of(static_def_id);
438 let locations = location.to_locations();
439 let normalized_ty = self.cx.normalize(unnormalized_ty, locations);
440 let literal_ty = constant.literal.ty().builtin_deref(true).unwrap().ty;
442 if let Err(terr) = self.cx.eq_types(
446 ConstraintCategory::Boring,
448 span_mirbug!(self, constant, "bad static type {:?} ({:?})", constant, terr);
452 if let ty::FnDef(def_id, substs) = *constant.literal.ty().kind() {
453 let instantiated_predicates = tcx.predicates_of(def_id).instantiate(tcx, substs);
454 self.cx.normalize_and_prove_instantiated_predicates(
456 instantiated_predicates,
457 location.to_locations(),
463 fn visit_rvalue(&mut self, rvalue: &Rvalue<'tcx>, location: Location) {
464 self.super_rvalue(rvalue, location);
465 let rval_ty = rvalue.ty(self.body(), self.tcx());
466 self.sanitize_type(rvalue, rval_ty);
469 fn visit_local_decl(&mut self, local: Local, local_decl: &LocalDecl<'tcx>) {
470 self.super_local_decl(local, local_decl);
471 self.sanitize_type(local_decl, local_decl.ty);
473 if let Some(user_ty) = &local_decl.user_ty {
474 for (user_ty, span) in user_ty.projections_and_spans() {
475 let ty = if !local_decl.is_nonref_binding() {
476 // If we have a binding of the form `let ref x: T = ..`
477 // then remove the outermost reference so we can check the
478 // type annotation for the remaining type.
479 if let ty::Ref(_, rty, _) = local_decl.ty.kind() {
482 bug!("{:?} with ref binding has wrong type {}", local, local_decl.ty);
488 if let Err(terr) = self.cx.relate_type_and_user_type(
490 ty::Variance::Invariant,
492 Locations::All(*span),
493 ConstraintCategory::TypeAnnotation,
498 "bad user type on variable {:?}: {:?} != {:?} ({:?})",
509 fn visit_body(&mut self, body: &Body<'tcx>) {
510 self.sanitize_type(&"return type", body.return_ty());
511 for local_decl in &body.local_decls {
512 self.sanitize_type(local_decl, local_decl.ty);
514 if self.errors_reported {
517 self.super_body(body);
521 impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
523 cx: &'a mut TypeChecker<'b, 'tcx>,
524 promoted: &'b IndexVec<Promoted, Body<'tcx>>,
526 TypeVerifier { promoted, last_span: cx.body.span, cx, errors_reported: false }
529 fn body(&self) -> &Body<'tcx> {
533 fn tcx(&self) -> TyCtxt<'tcx> {
537 fn sanitize_type(&mut self, parent: &dyn fmt::Debug, ty: Ty<'tcx>) -> Ty<'tcx> {
538 if ty.has_escaping_bound_vars() || ty.references_error() {
539 span_mirbug_and_err!(self, parent, "bad type {:?}", ty)
545 /// Checks that the types internal to the `place` match up with
546 /// what would be expected.
551 context: PlaceContext,
553 debug!("sanitize_place: {:?}", place);
555 let mut place_ty = PlaceTy::from_ty(self.body().local_decls[place.local].ty);
557 for elem in place.projection.iter() {
558 if place_ty.variant_index.is_none() {
559 if place_ty.ty.references_error() {
560 assert!(self.errors_reported);
561 return PlaceTy::from_ty(self.tcx().ty_error());
564 place_ty = self.sanitize_projection(place_ty, elem, place, location);
567 if let PlaceContext::NonMutatingUse(NonMutatingUseContext::Copy) = context {
568 let tcx = self.tcx();
569 let trait_ref = ty::TraitRef {
570 def_id: tcx.require_lang_item(LangItem::Copy, Some(self.last_span)),
571 substs: tcx.mk_substs_trait(place_ty.ty, &[]),
574 // To have a `Copy` operand, the type `T` of the
575 // value must be `Copy`. Note that we prove that `T: Copy`,
576 // rather than using the `is_copy_modulo_regions`
577 // test. This is important because
578 // `is_copy_modulo_regions` ignores the resulting region
579 // obligations and assumes they pass. This can result in
580 // bounds from `Copy` impls being unsoundly ignored (e.g.,
581 // #29149). Note that we decide to use `Copy` before knowing
582 // whether the bounds fully apply: in effect, the rule is
583 // that if a value of some type could implement `Copy`, then
585 self.cx.prove_trait_ref(
587 location.to_locations(),
588 ConstraintCategory::CopyBound,
595 fn sanitize_promoted(&mut self, promoted_body: &'b Body<'tcx>, location: Location) {
596 // Determine the constraints from the promoted MIR by running the type
597 // checker on the promoted MIR, then transfer the constraints back to
598 // the main MIR, changing the locations to the provided location.
600 let parent_body = mem::replace(&mut self.cx.body, promoted_body);
602 // Use new sets of constraints and closure bounds so that we can
603 // modify their locations.
604 let all_facts = &mut None;
605 let mut constraints = Default::default();
606 let mut closure_bounds = Default::default();
607 let mut liveness_constraints =
608 LivenessValues::new(Rc::new(RegionValueElements::new(&promoted_body)));
609 // Don't try to add borrow_region facts for the promoted MIR
611 let mut swap_constraints = |this: &mut Self| {
612 mem::swap(this.cx.borrowck_context.all_facts, all_facts);
614 &mut this.cx.borrowck_context.constraints.outlives_constraints,
618 &mut this.cx.borrowck_context.constraints.closure_bounds_mapping,
622 &mut this.cx.borrowck_context.constraints.liveness_constraints,
623 &mut liveness_constraints,
627 swap_constraints(self);
629 self.visit_body(&promoted_body);
631 if !self.errors_reported {
632 // if verifier failed, don't do further checks to avoid ICEs
633 self.cx.typeck_mir(promoted_body);
636 self.cx.body = parent_body;
637 // Merge the outlives constraints back in, at the given location.
638 swap_constraints(self);
640 let locations = location.to_locations();
641 for constraint in constraints.outlives().iter() {
642 let mut constraint = constraint.clone();
643 constraint.locations = locations;
644 if let ConstraintCategory::Return(_)
645 | ConstraintCategory::UseAsConst
646 | ConstraintCategory::UseAsStatic = constraint.category
648 // "Returning" from a promoted is an assignment to a
649 // temporary from the user's point of view.
650 constraint.category = ConstraintCategory::Boring;
652 self.cx.borrowck_context.constraints.outlives_constraints.push(constraint)
654 for region in liveness_constraints.rows() {
655 // If the region is live at at least one location in the promoted MIR,
656 // then add a liveness constraint to the main MIR for this region
657 // at the location provided as an argument to this method
658 if liveness_constraints.get_elements(region).next().is_some() {
662 .liveness_constraints
663 .add_element(region, location);
667 if !closure_bounds.is_empty() {
668 let combined_bounds_mapping =
669 closure_bounds.into_iter().flat_map(|(_, value)| value).collect();
674 .closure_bounds_mapping
675 .insert(location, combined_bounds_mapping);
676 assert!(existing.is_none(), "Multiple promoteds/closures at the same location.");
680 fn sanitize_projection(
687 debug!("sanitize_projection: {:?} {:?} {:?}", base, pi, place);
688 let tcx = self.tcx();
689 let base_ty = base.ty;
691 ProjectionElem::Deref => {
692 let deref_ty = base_ty.builtin_deref(true);
693 PlaceTy::from_ty(deref_ty.map(|t| t.ty).unwrap_or_else(|| {
694 span_mirbug_and_err!(self, place, "deref of non-pointer {:?}", base_ty)
697 ProjectionElem::Index(i) => {
698 let index_ty = Place::from(i).ty(self.body(), tcx).ty;
699 if index_ty != tcx.types.usize {
700 PlaceTy::from_ty(span_mirbug_and_err!(self, i, "index by non-usize {:?}", i))
702 PlaceTy::from_ty(base_ty.builtin_index().unwrap_or_else(|| {
703 span_mirbug_and_err!(self, place, "index of non-array {:?}", base_ty)
707 ProjectionElem::ConstantIndex { .. } => {
708 // consider verifying in-bounds
709 PlaceTy::from_ty(base_ty.builtin_index().unwrap_or_else(|| {
710 span_mirbug_and_err!(self, place, "index of non-array {:?}", base_ty)
713 ProjectionElem::Subslice { from, to, from_end } => {
714 PlaceTy::from_ty(match base_ty.kind() {
715 ty::Array(inner, _) => {
716 assert!(!from_end, "array subslices should not use from_end");
717 tcx.mk_array(*inner, to - from)
720 assert!(from_end, "slice subslices should use from_end");
723 _ => span_mirbug_and_err!(self, place, "slice of non-array {:?}", base_ty),
726 ProjectionElem::Downcast(maybe_name, index) => match base_ty.kind() {
727 ty::Adt(adt_def, _substs) if adt_def.is_enum() => {
728 if index.as_usize() >= adt_def.variants().len() {
729 PlaceTy::from_ty(span_mirbug_and_err!(
732 "cast to variant #{:?} but enum only has {:?}",
734 adt_def.variants().len()
737 PlaceTy { ty: base_ty, variant_index: Some(index) }
740 // We do not need to handle generators here, because this runs
741 // before the generator transform stage.
743 let ty = if let Some(name) = maybe_name {
744 span_mirbug_and_err!(
747 "can't downcast {:?} as {:?}",
752 span_mirbug_and_err!(self, place, "can't downcast {:?}", base_ty)
757 ProjectionElem::Field(field, fty) => {
758 let fty = self.sanitize_type(place, fty);
759 let fty = self.cx.normalize(fty, location);
760 match self.field_ty(place, base, field, location) {
762 let ty = self.cx.normalize(ty, location);
763 if let Err(terr) = self.cx.eq_types(
766 location.to_locations(),
767 ConstraintCategory::Boring,
772 "bad field access ({:?}: {:?}): {:?}",
779 Err(FieldAccessError::OutOfRange { field_count }) => span_mirbug!(
782 "accessed field #{} but variant only has {}",
787 PlaceTy::from_ty(fty)
792 fn error(&mut self) -> Ty<'tcx> {
793 self.errors_reported = true;
794 self.tcx().ty_error()
799 parent: &dyn fmt::Debug,
800 base_ty: PlaceTy<'tcx>,
803 ) -> Result<Ty<'tcx>, FieldAccessError> {
804 let tcx = self.tcx();
806 let (variant, substs) = match base_ty {
807 PlaceTy { ty, variant_index: Some(variant_index) } => match *ty.kind() {
808 ty::Adt(adt_def, substs) => (adt_def.variant(variant_index), substs),
809 ty::Generator(def_id, substs, _) => {
810 let mut variants = substs.as_generator().state_tys(def_id, tcx);
811 let Some(mut variant) = variants.nth(variant_index.into()) else {
813 "variant_index of generator out of range: {:?}/{:?}",
815 substs.as_generator().state_tys(def_id, tcx).count()
818 return match variant.nth(field.index()) {
820 None => Err(FieldAccessError::OutOfRange { field_count: variant.count() }),
823 _ => bug!("can't have downcast of non-adt non-generator type"),
825 PlaceTy { ty, variant_index: None } => match *ty.kind() {
826 ty::Adt(adt_def, substs) if !adt_def.is_enum() => {
827 (adt_def.variant(VariantIdx::new(0)), substs)
829 ty::Closure(_, substs) => {
837 None => Err(FieldAccessError::OutOfRange {
838 field_count: substs.as_closure().upvar_tys().count(),
842 ty::Generator(_, substs, _) => {
843 // Only prefix fields (upvars and current state) are
844 // accessible without a variant index.
845 return match substs.as_generator().prefix_tys().nth(field.index()) {
847 None => Err(FieldAccessError::OutOfRange {
848 field_count: substs.as_generator().prefix_tys().count(),
853 return match tys.get(field.index()) {
855 None => Err(FieldAccessError::OutOfRange { field_count: tys.len() }),
859 return Ok(span_mirbug_and_err!(
862 "can't project out of {:?}",
869 if let Some(field) = variant.fields.get(field.index()) {
870 Ok(self.cx.normalize(field.ty(tcx, substs), location))
872 Err(FieldAccessError::OutOfRange { field_count: variant.fields.len() })
877 /// The MIR type checker. Visits the MIR and enforces all the
878 /// constraints needed for it to be valid and well-typed. Along the
879 /// way, it accrues region constraints -- these can later be used by
880 /// NLL region checking.
881 struct TypeChecker<'a, 'tcx> {
882 infcx: &'a InferCtxt<'a, 'tcx>,
883 param_env: ty::ParamEnv<'tcx>,
885 body: &'a Body<'tcx>,
886 /// User type annotations are shared between the main MIR and the MIR of
887 /// all of the promoted items.
888 user_type_annotations: &'a CanonicalUserTypeAnnotations<'tcx>,
889 region_bound_pairs: &'a RegionBoundPairs<'tcx>,
890 implicit_region_bound: ty::Region<'tcx>,
891 reported_errors: FxHashSet<(Ty<'tcx>, Span)>,
892 borrowck_context: &'a mut BorrowCheckContext<'a, 'tcx>,
895 struct BorrowCheckContext<'a, 'tcx> {
896 pub(crate) universal_regions: &'a UniversalRegions<'tcx>,
897 location_table: &'a LocationTable,
898 all_facts: &'a mut Option<AllFacts>,
899 borrow_set: &'a BorrowSet<'tcx>,
900 pub(crate) constraints: &'a mut MirTypeckRegionConstraints<'tcx>,
901 upvars: &'a [Upvar<'tcx>],
904 pub(crate) struct MirTypeckResults<'tcx> {
905 pub(crate) constraints: MirTypeckRegionConstraints<'tcx>,
906 pub(crate) universal_region_relations: Frozen<UniversalRegionRelations<'tcx>>,
907 pub(crate) opaque_type_values:
908 VecMap<OpaqueTypeKey<'tcx>, (OpaqueHiddenType<'tcx>, OpaqueTyOrigin)>,
911 /// A collection of region constraints that must be satisfied for the
912 /// program to be considered well-typed.
913 pub(crate) struct MirTypeckRegionConstraints<'tcx> {
914 /// Maps from a `ty::Placeholder` to the corresponding
915 /// `PlaceholderIndex` bit that we will use for it.
917 /// To keep everything in sync, do not insert this set
918 /// directly. Instead, use the `placeholder_region` helper.
919 pub(crate) placeholder_indices: PlaceholderIndices,
921 /// Each time we add a placeholder to `placeholder_indices`, we
922 /// also create a corresponding "representative" region vid for
923 /// that wraps it. This vector tracks those. This way, when we
924 /// convert the same `ty::RePlaceholder(p)` twice, we can map to
925 /// the same underlying `RegionVid`.
926 pub(crate) placeholder_index_to_region: IndexVec<PlaceholderIndex, ty::Region<'tcx>>,
928 /// In general, the type-checker is not responsible for enforcing
929 /// liveness constraints; this job falls to the region inferencer,
930 /// which performs a liveness analysis. However, in some limited
931 /// cases, the MIR type-checker creates temporary regions that do
932 /// not otherwise appear in the MIR -- in particular, the
933 /// late-bound regions that it instantiates at call-sites -- and
934 /// hence it must report on their liveness constraints.
935 pub(crate) liveness_constraints: LivenessValues<RegionVid>,
937 pub(crate) outlives_constraints: OutlivesConstraintSet<'tcx>,
939 pub(crate) member_constraints: MemberConstraintSet<'tcx, RegionVid>,
941 pub(crate) closure_bounds_mapping:
942 FxHashMap<Location, FxHashMap<(RegionVid, RegionVid), (ConstraintCategory<'tcx>, Span)>>,
944 pub(crate) universe_causes: FxHashMap<ty::UniverseIndex, UniverseInfo<'tcx>>,
946 pub(crate) type_tests: Vec<TypeTest<'tcx>>,
949 impl<'tcx> MirTypeckRegionConstraints<'tcx> {
950 fn placeholder_region(
952 infcx: &InferCtxt<'_, 'tcx>,
953 placeholder: ty::PlaceholderRegion,
954 ) -> ty::Region<'tcx> {
955 let placeholder_index = self.placeholder_indices.insert(placeholder);
956 match self.placeholder_index_to_region.get(placeholder_index) {
959 let origin = NllRegionVariableOrigin::Placeholder(placeholder);
960 let region = infcx.next_nll_region_var_in_universe(origin, placeholder.universe);
961 self.placeholder_index_to_region.push(region);
968 /// The `Locations` type summarizes *where* region constraints are
969 /// required to hold. Normally, this is at a particular point which
970 /// created the obligation, but for constraints that the user gave, we
971 /// want the constraint to hold at all points.
972 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
974 /// Indicates that a type constraint should always be true. This
975 /// is particularly important in the new borrowck analysis for
976 /// things like the type of the return slot. Consider this
979 /// ```compile_fail,E0515
980 /// fn foo<'a>(x: &'a u32) -> &'a u32 {
982 /// return &y; // error
986 /// Here, we wind up with the signature from the return type being
987 /// something like `&'1 u32` where `'1` is a universal region. But
988 /// the type of the return slot `_0` is something like `&'2 u32`
989 /// where `'2` is an existential region variable. The type checker
990 /// requires that `&'2 u32 = &'1 u32` -- but at what point? In the
991 /// older NLL analysis, we required this only at the entry point
992 /// to the function. By the nature of the constraints, this wound
993 /// up propagating to all points reachable from start (because
994 /// `'1` -- as a universal region -- is live everywhere). In the
995 /// newer analysis, though, this doesn't work: `_0` is considered
996 /// dead at the start (it has no usable value) and hence this type
997 /// equality is basically a no-op. Then, later on, when we do `_0
998 /// = &'3 y`, that region `'3` never winds up related to the
999 /// universal region `'1` and hence no error occurs. Therefore, we
1000 /// use Locations::All instead, which ensures that the `'1` and
1001 /// `'2` are equal everything. We also use this for other
1002 /// user-given type annotations; e.g., if the user wrote `let mut
1003 /// x: &'static u32 = ...`, we would ensure that all values
1004 /// assigned to `x` are of `'static` lifetime.
1006 /// The span points to the place the constraint arose. For example,
1007 /// it points to the type in a user-given type annotation. If
1008 /// there's no sensible span then it's DUMMY_SP.
1011 /// An outlives constraint that only has to hold at a single location,
1012 /// usually it represents a point where references flow from one spot to
1013 /// another (e.g., `x = y`)
1018 pub fn from_location(&self) -> Option<Location> {
1020 Locations::All(_) => None,
1021 Locations::Single(from_location) => Some(*from_location),
1025 /// Gets a span representing the location.
1026 pub fn span(&self, body: &Body<'_>) -> Span {
1028 Locations::All(span) => *span,
1029 Locations::Single(l) => body.source_info(*l).span,
1034 impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
1036 infcx: &'a InferCtxt<'a, 'tcx>,
1037 body: &'a Body<'tcx>,
1038 param_env: ty::ParamEnv<'tcx>,
1039 region_bound_pairs: &'a RegionBoundPairs<'tcx>,
1040 implicit_region_bound: ty::Region<'tcx>,
1041 borrowck_context: &'a mut BorrowCheckContext<'a, 'tcx>,
1043 let mut checker = Self {
1045 last_span: DUMMY_SP,
1047 user_type_annotations: &body.user_type_annotations,
1050 implicit_region_bound,
1052 reported_errors: Default::default(),
1054 checker.check_user_type_annotations();
1058 fn body(&self) -> &Body<'tcx> {
1062 fn unsized_feature_enabled(&self) -> bool {
1063 let features = self.tcx().features();
1064 features.unsized_locals || features.unsized_fn_params
1067 /// Equate the inferred type and the annotated type for user type annotations
1068 #[instrument(skip(self), level = "debug")]
1069 fn check_user_type_annotations(&mut self) {
1070 debug!(?self.user_type_annotations);
1071 for user_annotation in self.user_type_annotations {
1072 let CanonicalUserTypeAnnotation { span, ref user_ty, inferred_ty } = *user_annotation;
1073 let inferred_ty = self.normalize(inferred_ty, Locations::All(span));
1074 let annotation = self.instantiate_canonical_with_fresh_inference_vars(span, user_ty);
1076 UserType::Ty(mut ty) => {
1077 ty = self.normalize(ty, Locations::All(span));
1079 if let Err(terr) = self.eq_types(
1082 Locations::All(span),
1083 ConstraintCategory::BoringNoLocation,
1088 "bad user type ({:?} = {:?}): {:?}",
1095 self.prove_predicate(
1096 ty::Binder::dummy(ty::PredicateKind::WellFormed(inferred_ty.into()))
1097 .to_predicate(self.tcx()),
1098 Locations::All(span),
1099 ConstraintCategory::TypeAnnotation,
1102 UserType::TypeOf(def_id, user_substs) => {
1103 if let Err(terr) = self.fully_perform_op(
1104 Locations::All(span),
1105 ConstraintCategory::BoringNoLocation,
1106 self.param_env.and(type_op::ascribe_user_type::AscribeUserType::new(
1115 "bad user type AscribeUserType({:?}, {:?} {:?}, type_of={:?}): {:?}",
1119 self.tcx().type_of(def_id),
1128 #[instrument(skip(self, data), level = "debug")]
1129 fn push_region_constraints(
1131 locations: Locations,
1132 category: ConstraintCategory<'tcx>,
1133 data: &QueryRegionConstraints<'tcx>,
1135 debug!("constraints generated: {:#?}", data);
1137 constraint_conversion::ConstraintConversion::new(
1139 self.borrowck_context.universal_regions,
1140 self.region_bound_pairs,
1141 Some(self.implicit_region_bound),
1144 locations.span(self.body),
1146 &mut self.borrowck_context.constraints,
1151 /// Try to relate `sub <: sup`
1156 locations: Locations,
1157 category: ConstraintCategory<'tcx>,
1159 // Use this order of parameters because the sup type is usually the
1160 // "expected" type in diagnostics.
1161 self.relate_types(sup, ty::Variance::Contravariant, sub, locations, category)
1164 #[instrument(skip(self, category), level = "debug")]
1169 locations: Locations,
1170 category: ConstraintCategory<'tcx>,
1172 self.relate_types(expected, ty::Variance::Invariant, found, locations, category)
1175 #[instrument(skip(self), level = "debug")]
1176 fn relate_type_and_user_type(
1180 user_ty: &UserTypeProjection,
1181 locations: Locations,
1182 category: ConstraintCategory<'tcx>,
1184 let annotated_type = self.user_type_annotations[user_ty.base].inferred_ty;
1185 let mut curr_projected_ty = PlaceTy::from_ty(annotated_type);
1187 let tcx = self.infcx.tcx;
1189 for proj in &user_ty.projs {
1190 let projected_ty = curr_projected_ty.projection_ty_core(
1195 let ty = this.field_ty(tcx, field);
1196 self.normalize(ty, locations)
1199 curr_projected_ty = projected_ty;
1202 "user_ty base: {:?} freshened: {:?} projs: {:?} yields: {:?}",
1203 user_ty.base, annotated_type, user_ty.projs, curr_projected_ty
1206 let ty = curr_projected_ty.ty;
1207 self.relate_types(ty, v.xform(ty::Variance::Contravariant), a, locations, category)?;
1212 fn tcx(&self) -> TyCtxt<'tcx> {
1216 #[instrument(skip(self, body, location), level = "debug")]
1217 fn check_stmt(&mut self, body: &Body<'tcx>, stmt: &Statement<'tcx>, location: Location) {
1218 let tcx = self.tcx();
1219 debug!("stmt kind: {:?}", stmt.kind);
1221 StatementKind::Assign(box (ref place, ref rv)) => {
1222 // Assignments to temporaries are not "interesting";
1223 // they are not caused by the user, but rather artifacts
1224 // of lowering. Assignments to other sorts of places *are* interesting
1226 let category = match place.as_local() {
1227 Some(RETURN_PLACE) => {
1228 let defining_ty = &self.borrowck_context.universal_regions.defining_ty;
1229 if defining_ty.is_const() {
1230 if tcx.is_static(defining_ty.def_id()) {
1231 ConstraintCategory::UseAsStatic
1233 ConstraintCategory::UseAsConst
1236 ConstraintCategory::Return(ReturnConstraint::Normal)
1241 body.local_decls[l].local_info,
1242 Some(box LocalInfo::AggregateTemp)
1245 ConstraintCategory::Usage
1247 Some(l) if !body.local_decls[l].is_user_variable() => {
1248 ConstraintCategory::Boring
1250 _ => ConstraintCategory::Assignment,
1253 "assignment category: {:?} {:?}",
1255 place.as_local().map(|l| &body.local_decls[l])
1258 let place_ty = place.ty(body, tcx).ty;
1260 let place_ty = self.normalize(place_ty, location);
1261 debug!("place_ty normalized: {:?}", place_ty);
1262 let rv_ty = rv.ty(body, tcx);
1264 let rv_ty = self.normalize(rv_ty, location);
1265 debug!("normalized rv_ty: {:?}", rv_ty);
1267 self.sub_types(rv_ty, place_ty, location.to_locations(), category)
1272 "bad assignment ({:?} = {:?}): {:?}",
1279 if let Some(annotation_index) = self.rvalue_user_ty(rv) {
1280 if let Err(terr) = self.relate_type_and_user_type(
1282 ty::Variance::Invariant,
1283 &UserTypeProjection { base: annotation_index, projs: vec![] },
1284 location.to_locations(),
1285 ConstraintCategory::Boring,
1287 let annotation = &self.user_type_annotations[annotation_index];
1291 "bad user type on rvalue ({:?} = {:?}): {:?}",
1299 self.check_rvalue(body, rv, location);
1300 if !self.unsized_feature_enabled() {
1301 let trait_ref = ty::TraitRef {
1302 def_id: tcx.require_lang_item(LangItem::Sized, Some(self.last_span)),
1303 substs: tcx.mk_substs_trait(place_ty, &[]),
1305 self.prove_trait_ref(
1307 location.to_locations(),
1308 ConstraintCategory::SizedBound,
1312 StatementKind::AscribeUserType(box (ref place, ref projection), variance) => {
1313 let place_ty = place.ty(body, tcx).ty;
1314 if let Err(terr) = self.relate_type_and_user_type(
1318 Locations::All(stmt.source_info.span),
1319 ConstraintCategory::TypeAnnotation,
1321 let annotation = &self.user_type_annotations[projection.base];
1325 "bad type assert ({:?} <: {:?} with projections {:?}): {:?}",
1333 StatementKind::CopyNonOverlapping(box rustc_middle::mir::CopyNonOverlapping {
1336 stmt.source_info.span,
1337 "Unexpected StatementKind::CopyNonOverlapping, should only appear after lowering_intrinsics",
1339 StatementKind::FakeRead(..)
1340 | StatementKind::StorageLive(..)
1341 | StatementKind::StorageDead(..)
1342 | StatementKind::Retag { .. }
1343 | StatementKind::Coverage(..)
1344 | StatementKind::Nop => {}
1345 StatementKind::Deinit(..) | StatementKind::SetDiscriminant { .. } => {
1346 bug!("Statement not allowed in this MIR phase")
1351 #[instrument(skip(self, body, term_location), level = "debug")]
1352 fn check_terminator(
1355 term: &Terminator<'tcx>,
1356 term_location: Location,
1358 let tcx = self.tcx();
1359 debug!("terminator kind: {:?}", term.kind);
1361 TerminatorKind::Goto { .. }
1362 | TerminatorKind::Resume
1363 | TerminatorKind::Abort
1364 | TerminatorKind::Return
1365 | TerminatorKind::GeneratorDrop
1366 | TerminatorKind::Unreachable
1367 | TerminatorKind::Drop { .. }
1368 | TerminatorKind::FalseEdge { .. }
1369 | TerminatorKind::FalseUnwind { .. }
1370 | TerminatorKind::InlineAsm { .. } => {
1371 // no checks needed for these
1374 TerminatorKind::DropAndReplace { ref place, ref value, target: _, unwind: _ } => {
1375 let place_ty = place.ty(body, tcx).ty;
1376 let rv_ty = value.ty(body, tcx);
1378 let locations = term_location.to_locations();
1380 self.sub_types(rv_ty, place_ty, locations, ConstraintCategory::Assignment)
1385 "bad DropAndReplace ({:?} = {:?}): {:?}",
1392 TerminatorKind::SwitchInt { ref discr, switch_ty, .. } => {
1393 self.check_operand(discr, term_location);
1395 let discr_ty = discr.ty(body, tcx);
1396 if let Err(terr) = self.sub_types(
1399 term_location.to_locations(),
1400 ConstraintCategory::Assignment,
1405 "bad SwitchInt ({:?} on {:?}): {:?}",
1411 if !switch_ty.is_integral() && !switch_ty.is_char() && !switch_ty.is_bool() {
1412 span_mirbug!(self, term, "bad SwitchInt discr ty {:?}", switch_ty);
1414 // FIXME: check the values
1416 TerminatorKind::Call {
1424 self.check_operand(func, term_location);
1426 self.check_operand(arg, term_location);
1429 let func_ty = func.ty(body, tcx);
1430 debug!("func_ty.kind: {:?}", func_ty.kind());
1432 let sig = match func_ty.kind() {
1433 ty::FnDef(..) | ty::FnPtr(_) => func_ty.fn_sig(tcx),
1435 span_mirbug!(self, term, "call to non-function {:?}", func_ty);
1439 let (sig, map) = self.infcx.replace_bound_vars_with_fresh_vars(
1440 term.source_info.span,
1441 LateBoundRegionConversionTime::FnCall,
1445 let sig = self.normalize(sig, term_location);
1446 self.check_call_dest(body, term, &sig, *destination, target, term_location);
1448 self.prove_predicates(
1449 sig.inputs_and_output
1451 .map(|ty| ty::Binder::dummy(ty::PredicateKind::WellFormed(ty.into()))),
1452 term_location.to_locations(),
1453 ConstraintCategory::Boring,
1456 // The ordinary liveness rules will ensure that all
1457 // regions in the type of the callee are live here. We
1458 // then further constrain the late-bound regions that
1459 // were instantiated at the call site to be live as
1460 // well. The resulting is that all the input (and
1461 // output) types in the signature must be live, since
1462 // all the inputs that fed into it were live.
1463 for &late_bound_region in map.values() {
1465 self.borrowck_context.universal_regions.to_region_vid(late_bound_region);
1466 self.borrowck_context
1468 .liveness_constraints
1469 .add_element(region_vid, term_location);
1472 self.check_call_inputs(body, term, &sig, args, term_location, from_hir_call);
1474 TerminatorKind::Assert { ref cond, ref msg, .. } => {
1475 self.check_operand(cond, term_location);
1477 let cond_ty = cond.ty(body, tcx);
1478 if cond_ty != tcx.types.bool {
1479 span_mirbug!(self, term, "bad Assert ({:?}, not bool", cond_ty);
1482 if let AssertKind::BoundsCheck { ref len, ref index } = *msg {
1483 if len.ty(body, tcx) != tcx.types.usize {
1484 span_mirbug!(self, len, "bounds-check length non-usize {:?}", len)
1486 if index.ty(body, tcx) != tcx.types.usize {
1487 span_mirbug!(self, index, "bounds-check index non-usize {:?}", index)
1491 TerminatorKind::Yield { ref value, .. } => {
1492 self.check_operand(value, term_location);
1494 let value_ty = value.ty(body, tcx);
1495 match body.yield_ty() {
1496 None => span_mirbug!(self, term, "yield in non-generator"),
1498 if let Err(terr) = self.sub_types(
1501 term_location.to_locations(),
1502 ConstraintCategory::Yield,
1507 "type of yield value is {:?}, but the yield type is {:?}: {:?}",
1522 term: &Terminator<'tcx>,
1523 sig: &ty::FnSig<'tcx>,
1524 destination: Place<'tcx>,
1525 target: Option<BasicBlock>,
1526 term_location: Location,
1528 let tcx = self.tcx();
1531 let dest_ty = destination.ty(body, tcx).ty;
1532 let dest_ty = self.normalize(dest_ty, term_location);
1533 let category = match destination.as_local() {
1534 Some(RETURN_PLACE) => {
1535 if let BorrowCheckContext {
1539 DefiningTy::Const(def_id, _)
1540 | DefiningTy::InlineConst(def_id, _),
1544 } = self.borrowck_context
1546 if tcx.is_static(*def_id) {
1547 ConstraintCategory::UseAsStatic
1549 ConstraintCategory::UseAsConst
1552 ConstraintCategory::Return(ReturnConstraint::Normal)
1555 Some(l) if !body.local_decls[l].is_user_variable() => {
1556 ConstraintCategory::Boring
1558 _ => ConstraintCategory::Assignment,
1561 let locations = term_location.to_locations();
1563 if let Err(terr) = self.sub_types(sig.output(), dest_ty, locations, category) {
1567 "call dest mismatch ({:?} <- {:?}): {:?}",
1574 // When `unsized_fn_params` and `unsized_locals` are both not enabled,
1575 // this check is done at `check_local`.
1576 if self.unsized_feature_enabled() {
1577 let span = term.source_info.span;
1578 self.ensure_place_sized(dest_ty, span);
1584 .conservative_is_privately_uninhabited(self.param_env.and(sig.output()))
1586 span_mirbug!(self, term, "call to converging function {:?} w/o dest", sig);
1592 fn check_call_inputs(
1595 term: &Terminator<'tcx>,
1596 sig: &ty::FnSig<'tcx>,
1597 args: &[Operand<'tcx>],
1598 term_location: Location,
1599 from_hir_call: bool,
1601 debug!("check_call_inputs({:?}, {:?})", sig, args);
1602 if args.len() < sig.inputs().len() || (args.len() > sig.inputs().len() && !sig.c_variadic) {
1603 span_mirbug!(self, term, "call to {:?} with wrong # of args", sig);
1606 let func_ty = if let TerminatorKind::Call { func, .. } = &term.kind {
1607 Some(func.ty(body, self.infcx.tcx))
1613 for (n, (fn_arg, op_arg)) in iter::zip(sig.inputs(), args).enumerate() {
1614 let op_arg_ty = op_arg.ty(body, self.tcx());
1616 let op_arg_ty = self.normalize(op_arg_ty, term_location);
1617 let category = if from_hir_call {
1618 ConstraintCategory::CallArgument(func_ty)
1620 ConstraintCategory::Boring
1623 self.sub_types(op_arg_ty, *fn_arg, term_location.to_locations(), category)
1628 "bad arg #{:?} ({:?} <- {:?}): {:?}",
1638 fn check_iscleanup(&mut self, body: &Body<'tcx>, block_data: &BasicBlockData<'tcx>) {
1639 let is_cleanup = block_data.is_cleanup;
1640 self.last_span = block_data.terminator().source_info.span;
1641 match block_data.terminator().kind {
1642 TerminatorKind::Goto { target } => {
1643 self.assert_iscleanup(body, block_data, target, is_cleanup)
1645 TerminatorKind::SwitchInt { ref targets, .. } => {
1646 for target in targets.all_targets() {
1647 self.assert_iscleanup(body, block_data, *target, is_cleanup);
1650 TerminatorKind::Resume => {
1652 span_mirbug!(self, block_data, "resume on non-cleanup block!")
1655 TerminatorKind::Abort => {
1657 span_mirbug!(self, block_data, "abort on non-cleanup block!")
1660 TerminatorKind::Return => {
1662 span_mirbug!(self, block_data, "return on cleanup block")
1665 TerminatorKind::GeneratorDrop { .. } => {
1667 span_mirbug!(self, block_data, "generator_drop in cleanup block")
1670 TerminatorKind::Yield { resume, drop, .. } => {
1672 span_mirbug!(self, block_data, "yield in cleanup block")
1674 self.assert_iscleanup(body, block_data, resume, is_cleanup);
1675 if let Some(drop) = drop {
1676 self.assert_iscleanup(body, block_data, drop, is_cleanup);
1679 TerminatorKind::Unreachable => {}
1680 TerminatorKind::Drop { target, unwind, .. }
1681 | TerminatorKind::DropAndReplace { target, unwind, .. }
1682 | TerminatorKind::Assert { target, cleanup: unwind, .. } => {
1683 self.assert_iscleanup(body, block_data, target, is_cleanup);
1684 if let Some(unwind) = unwind {
1686 span_mirbug!(self, block_data, "unwind on cleanup block")
1688 self.assert_iscleanup(body, block_data, unwind, true);
1691 TerminatorKind::Call { ref target, cleanup, .. } => {
1692 if let &Some(target) = target {
1693 self.assert_iscleanup(body, block_data, target, is_cleanup);
1695 if let Some(cleanup) = cleanup {
1697 span_mirbug!(self, block_data, "cleanup on cleanup block")
1699 self.assert_iscleanup(body, block_data, cleanup, true);
1702 TerminatorKind::FalseEdge { real_target, imaginary_target } => {
1703 self.assert_iscleanup(body, block_data, real_target, is_cleanup);
1704 self.assert_iscleanup(body, block_data, imaginary_target, is_cleanup);
1706 TerminatorKind::FalseUnwind { real_target, unwind } => {
1707 self.assert_iscleanup(body, block_data, real_target, is_cleanup);
1708 if let Some(unwind) = unwind {
1710 span_mirbug!(self, block_data, "cleanup in cleanup block via false unwind");
1712 self.assert_iscleanup(body, block_data, unwind, true);
1715 TerminatorKind::InlineAsm { destination, cleanup, .. } => {
1716 if let Some(target) = destination {
1717 self.assert_iscleanup(body, block_data, target, is_cleanup);
1719 if let Some(cleanup) = cleanup {
1721 span_mirbug!(self, block_data, "cleanup on cleanup block")
1723 self.assert_iscleanup(body, block_data, cleanup, true);
1729 fn assert_iscleanup(
1732 ctxt: &dyn fmt::Debug,
1736 if body[bb].is_cleanup != iscleanuppad {
1737 span_mirbug!(self, ctxt, "cleanuppad mismatch: {:?} should be {:?}", bb, iscleanuppad);
1741 fn check_local(&mut self, body: &Body<'tcx>, local: Local, local_decl: &LocalDecl<'tcx>) {
1742 match body.local_kind(local) {
1743 LocalKind::ReturnPointer | LocalKind::Arg => {
1744 // return values of normal functions are required to be
1745 // sized by typeck, but return values of ADT constructors are
1746 // not because we don't include a `Self: Sized` bounds on them.
1748 // Unbound parts of arguments were never required to be Sized
1749 // - maybe we should make that a warning.
1752 LocalKind::Var | LocalKind::Temp => {}
1755 // When `unsized_fn_params` or `unsized_locals` is enabled, only function calls
1756 // and nullary ops are checked in `check_call_dest`.
1757 if !self.unsized_feature_enabled() {
1758 let span = local_decl.source_info.span;
1759 let ty = local_decl.ty;
1760 self.ensure_place_sized(ty, span);
1764 fn ensure_place_sized(&mut self, ty: Ty<'tcx>, span: Span) {
1765 let tcx = self.tcx();
1767 // Erase the regions from `ty` to get a global type. The
1768 // `Sized` bound in no way depends on precise regions, so this
1769 // shouldn't affect `is_sized`.
1770 let erased_ty = tcx.erase_regions(ty);
1771 if !erased_ty.is_sized(tcx.at(span), self.param_env) {
1772 // in current MIR construction, all non-control-flow rvalue
1773 // expressions evaluate through `as_temp` or `into` a return
1774 // slot or local, so to find all unsized rvalues it is enough
1775 // to check all temps, return slots and locals.
1776 if self.reported_errors.replace((ty, span)).is_none() {
1777 let mut diag = struct_span_err!(
1781 "cannot move a value of type {0}: the size of {0} \
1782 cannot be statically determined",
1786 // While this is located in `nll::typeck` this error is not
1787 // an NLL error, it's a required check to prevent creation
1788 // of unsized rvalues in a call expression.
1794 fn aggregate_field_ty(
1796 ak: &AggregateKind<'tcx>,
1799 ) -> Result<Ty<'tcx>, FieldAccessError> {
1800 let tcx = self.tcx();
1803 AggregateKind::Adt(adt_did, variant_index, substs, _, active_field_index) => {
1804 let def = tcx.adt_def(adt_did);
1805 let variant = &def.variant(variant_index);
1806 let adj_field_index = active_field_index.unwrap_or(field_index);
1807 if let Some(field) = variant.fields.get(adj_field_index) {
1808 Ok(self.normalize(field.ty(tcx, substs), location))
1810 Err(FieldAccessError::OutOfRange { field_count: variant.fields.len() })
1813 AggregateKind::Closure(_, substs) => {
1814 match substs.as_closure().upvar_tys().nth(field_index) {
1816 None => Err(FieldAccessError::OutOfRange {
1817 field_count: substs.as_closure().upvar_tys().count(),
1821 AggregateKind::Generator(_, substs, _) => {
1822 // It doesn't make sense to look at a field beyond the prefix;
1823 // these require a variant index, and are not initialized in
1824 // aggregate rvalues.
1825 match substs.as_generator().prefix_tys().nth(field_index) {
1827 None => Err(FieldAccessError::OutOfRange {
1828 field_count: substs.as_generator().prefix_tys().count(),
1832 AggregateKind::Array(ty) => Ok(ty),
1833 AggregateKind::Tuple => {
1834 unreachable!("This should have been covered in check_rvalues");
1839 fn check_operand(&mut self, op: &Operand<'tcx>, location: Location) {
1840 if let Operand::Constant(constant) = op {
1841 let maybe_uneval = match constant.literal {
1842 ConstantKind::Ty(ct) => match ct.val() {
1843 ty::ConstKind::Unevaluated(uv) => Some(uv),
1848 if let Some(uv) = maybe_uneval {
1849 if uv.promoted.is_none() {
1850 let tcx = self.tcx();
1851 let def_id = uv.def.def_id_for_type_of();
1852 if tcx.def_kind(def_id) == DefKind::InlineConst {
1853 let predicates = self.prove_closure_bounds(
1855 def_id.expect_local(),
1859 self.normalize_and_prove_instantiated_predicates(
1862 location.to_locations(),
1870 #[instrument(skip(self, body), level = "debug")]
1871 fn check_rvalue(&mut self, body: &Body<'tcx>, rvalue: &Rvalue<'tcx>, location: Location) {
1872 let tcx = self.tcx();
1875 Rvalue::Aggregate(ak, ops) => {
1877 self.check_operand(op, location);
1879 self.check_aggregate_rvalue(&body, rvalue, ak, ops, location)
1882 Rvalue::Repeat(operand, len) => {
1883 self.check_operand(operand, location);
1885 // If the length cannot be evaluated we must assume that the length can be larger
1887 // If the length is larger than 1, the repeat expression will need to copy the
1888 // element, so we require the `Copy` trait.
1889 if len.try_eval_usize(tcx, self.param_env).map_or(true, |len| len > 1) {
1891 Operand::Copy(..) | Operand::Constant(..) => {
1892 // These are always okay: direct use of a const, or a value that can evidently be copied.
1894 Operand::Move(place) => {
1895 // Make sure that repeated elements implement `Copy`.
1896 let span = body.source_info(location).span;
1897 let ty = place.ty(body, tcx).ty;
1898 let trait_ref = ty::TraitRef::new(
1899 tcx.require_lang_item(LangItem::Copy, Some(span)),
1900 tcx.mk_substs_trait(ty, &[]),
1903 self.prove_trait_ref(
1905 Locations::Single(location),
1906 ConstraintCategory::CopyBound,
1913 &Rvalue::NullaryOp(_, ty) => {
1914 let trait_ref = ty::TraitRef {
1915 def_id: tcx.require_lang_item(LangItem::Sized, Some(self.last_span)),
1916 substs: tcx.mk_substs_trait(ty, &[]),
1919 self.prove_trait_ref(
1921 location.to_locations(),
1922 ConstraintCategory::SizedBound,
1926 Rvalue::ShallowInitBox(operand, ty) => {
1927 self.check_operand(operand, location);
1929 let trait_ref = ty::TraitRef {
1930 def_id: tcx.require_lang_item(LangItem::Sized, Some(self.last_span)),
1931 substs: tcx.mk_substs_trait(*ty, &[]),
1934 self.prove_trait_ref(
1936 location.to_locations(),
1937 ConstraintCategory::SizedBound,
1941 Rvalue::Cast(cast_kind, op, ty) => {
1942 self.check_operand(op, location);
1945 CastKind::Pointer(PointerCast::ReifyFnPointer) => {
1946 let fn_sig = op.ty(body, tcx).fn_sig(tcx);
1948 // The type that we see in the fcx is like
1949 // `foo::<'a, 'b>`, where `foo` is the path to a
1950 // function definition. When we extract the
1951 // signature, it comes from the `fn_sig` query,
1952 // and hence may contain unnormalized results.
1953 let fn_sig = self.normalize(fn_sig, location);
1955 let ty_fn_ptr_from = tcx.mk_fn_ptr(fn_sig);
1957 if let Err(terr) = self.eq_types(
1960 location.to_locations(),
1961 ConstraintCategory::Cast,
1966 "equating {:?} with {:?} yields {:?}",
1974 CastKind::Pointer(PointerCast::ClosureFnPointer(unsafety)) => {
1975 let sig = match op.ty(body, tcx).kind() {
1976 ty::Closure(_, substs) => substs.as_closure().sig(),
1979 let ty_fn_ptr_from = tcx.mk_fn_ptr(tcx.signature_unclosure(sig, *unsafety));
1981 if let Err(terr) = self.eq_types(
1984 location.to_locations(),
1985 ConstraintCategory::Cast,
1990 "equating {:?} with {:?} yields {:?}",
1998 CastKind::Pointer(PointerCast::UnsafeFnPointer) => {
1999 let fn_sig = op.ty(body, tcx).fn_sig(tcx);
2001 // The type that we see in the fcx is like
2002 // `foo::<'a, 'b>`, where `foo` is the path to a
2003 // function definition. When we extract the
2004 // signature, it comes from the `fn_sig` query,
2005 // and hence may contain unnormalized results.
2006 let fn_sig = self.normalize(fn_sig, location);
2008 let ty_fn_ptr_from = tcx.safe_to_unsafe_fn_ty(fn_sig);
2010 if let Err(terr) = self.eq_types(
2013 location.to_locations(),
2014 ConstraintCategory::Cast,
2019 "equating {:?} with {:?} yields {:?}",
2027 CastKind::Pointer(PointerCast::Unsize) => {
2029 let trait_ref = ty::TraitRef {
2031 .require_lang_item(LangItem::CoerceUnsized, Some(self.last_span)),
2032 substs: tcx.mk_substs_trait(op.ty(body, tcx), &[ty.into()]),
2035 self.prove_trait_ref(
2037 location.to_locations(),
2038 ConstraintCategory::Cast,
2042 CastKind::Pointer(PointerCast::MutToConstPointer) => {
2043 let ty::RawPtr(ty::TypeAndMut {
2045 mutbl: hir::Mutability::Mut,
2046 }) = op.ty(body, tcx).kind() else {
2050 "unexpected base type for cast {:?}",
2055 let ty::RawPtr(ty::TypeAndMut {
2057 mutbl: hir::Mutability::Not,
2058 }) = ty.kind() else {
2062 "unexpected target type for cast {:?}",
2067 if let Err(terr) = self.sub_types(
2070 location.to_locations(),
2071 ConstraintCategory::Cast,
2076 "relating {:?} with {:?} yields {:?}",
2084 CastKind::Pointer(PointerCast::ArrayToPointer) => {
2085 let ty_from = op.ty(body, tcx);
2087 let opt_ty_elem_mut = match ty_from.kind() {
2088 ty::RawPtr(ty::TypeAndMut { mutbl: array_mut, ty: array_ty }) => {
2089 match array_ty.kind() {
2090 ty::Array(ty_elem, _) => Some((ty_elem, *array_mut)),
2097 let Some((ty_elem, ty_mut)) = opt_ty_elem_mut else {
2101 "ArrayToPointer cast from unexpected type {:?}",
2107 let (ty_to, ty_to_mut) = match ty.kind() {
2108 ty::RawPtr(ty::TypeAndMut { mutbl: ty_to_mut, ty: ty_to }) => {
2115 "ArrayToPointer cast to unexpected type {:?}",
2122 if ty_to_mut == Mutability::Mut && ty_mut == Mutability::Not {
2126 "ArrayToPointer cast from const {:?} to mut {:?}",
2133 if let Err(terr) = self.sub_types(
2136 location.to_locations(),
2137 ConstraintCategory::Cast,
2142 "relating {:?} with {:?} yields {:?}",
2150 CastKind::PointerExposeAddress => {
2151 let ty_from = op.ty(body, tcx);
2152 let cast_ty_from = CastTy::from_ty(ty_from);
2153 let cast_ty_to = CastTy::from_ty(*ty);
2154 match (cast_ty_from, cast_ty_to) {
2155 (Some(CastTy::Ptr(_) | CastTy::FnPtr), Some(CastTy::Int(_))) => (),
2160 "Invalid PointerExposeAddress cast {:?} -> {:?}",
2168 CastKind::PointerFromExposedAddress => {
2169 let ty_from = op.ty(body, tcx);
2170 let cast_ty_from = CastTy::from_ty(ty_from);
2171 let cast_ty_to = CastTy::from_ty(*ty);
2172 match (cast_ty_from, cast_ty_to) {
2173 (Some(CastTy::Int(_)), Some(CastTy::Ptr(_))) => (),
2178 "Invalid PointerFromExposedAddress cast {:?} -> {:?}",
2187 let ty_from = op.ty(body, tcx);
2188 let cast_ty_from = CastTy::from_ty(ty_from);
2189 let cast_ty_to = CastTy::from_ty(*ty);
2190 // Misc casts are either between floats and ints, or one ptr type to another.
2191 match (cast_ty_from, cast_ty_to) {
2193 Some(CastTy::Int(_) | CastTy::Float),
2194 Some(CastTy::Int(_) | CastTy::Float),
2196 | (Some(CastTy::Ptr(_) | CastTy::FnPtr), Some(CastTy::Ptr(_))) => (),
2201 "Invalid Misc cast {:?} -> {:?}",
2211 Rvalue::Ref(region, _borrow_kind, borrowed_place) => {
2212 self.add_reborrow_constraint(&body, location, *region, borrowed_place);
2216 BinOp::Eq | BinOp::Ne | BinOp::Lt | BinOp::Le | BinOp::Gt | BinOp::Ge,
2219 self.check_operand(left, location);
2220 self.check_operand(right, location);
2222 let ty_left = left.ty(body, tcx);
2223 match ty_left.kind() {
2224 // Types with regions are comparable if they have a common super-type.
2225 ty::RawPtr(_) | ty::FnPtr(_) => {
2226 let ty_right = right.ty(body, tcx);
2227 let common_ty = self.infcx.next_ty_var(TypeVariableOrigin {
2228 kind: TypeVariableOriginKind::MiscVariable,
2229 span: body.source_info(location).span,
2234 location.to_locations(),
2235 ConstraintCategory::Boring,
2237 .unwrap_or_else(|err| {
2238 bug!("Could not equate type variable with {:?}: {:?}", ty_left, err)
2240 if let Err(terr) = self.sub_types(
2243 location.to_locations(),
2244 ConstraintCategory::Boring,
2249 "unexpected comparison types {:?} and {:?} yields {:?}",
2256 // For types with no regions we can just check that the
2257 // both operands have the same type.
2258 ty::Int(_) | ty::Uint(_) | ty::Bool | ty::Char | ty::Float(_)
2259 if ty_left == right.ty(body, tcx) => {}
2260 // Other types are compared by trait methods, not by
2261 // `Rvalue::BinaryOp`.
2265 "unexpected comparison types {:?} and {:?}",
2272 Rvalue::Use(operand) | Rvalue::UnaryOp(_, operand) => {
2273 self.check_operand(operand, location);
2276 Rvalue::BinaryOp(_, box (left, right))
2277 | Rvalue::CheckedBinaryOp(_, box (left, right)) => {
2278 self.check_operand(left, location);
2279 self.check_operand(right, location);
2282 Rvalue::AddressOf(..)
2283 | Rvalue::ThreadLocalRef(..)
2285 | Rvalue::Discriminant(..) => {}
2289 /// If this rvalue supports a user-given type annotation, then
2290 /// extract and return it. This represents the final type of the
2291 /// rvalue and will be unified with the inferred type.
2292 fn rvalue_user_ty(&self, rvalue: &Rvalue<'tcx>) -> Option<UserTypeAnnotationIndex> {
2295 | Rvalue::ThreadLocalRef(_)
2296 | Rvalue::Repeat(..)
2298 | Rvalue::AddressOf(..)
2301 | Rvalue::ShallowInitBox(..)
2302 | Rvalue::BinaryOp(..)
2303 | Rvalue::CheckedBinaryOp(..)
2304 | Rvalue::NullaryOp(..)
2305 | Rvalue::UnaryOp(..)
2306 | Rvalue::Discriminant(..) => None,
2308 Rvalue::Aggregate(aggregate, _) => match **aggregate {
2309 AggregateKind::Adt(_, _, _, user_ty, _) => user_ty,
2310 AggregateKind::Array(_) => None,
2311 AggregateKind::Tuple => None,
2312 AggregateKind::Closure(_, _) => None,
2313 AggregateKind::Generator(_, _, _) => None,
2318 fn check_aggregate_rvalue(
2321 rvalue: &Rvalue<'tcx>,
2322 aggregate_kind: &AggregateKind<'tcx>,
2323 operands: &[Operand<'tcx>],
2326 let tcx = self.tcx();
2328 self.prove_aggregate_predicates(aggregate_kind, location);
2330 if *aggregate_kind == AggregateKind::Tuple {
2331 // tuple rvalue field type is always the type of the op. Nothing to check here.
2335 for (i, operand) in operands.iter().enumerate() {
2336 let field_ty = match self.aggregate_field_ty(aggregate_kind, i, location) {
2337 Ok(field_ty) => field_ty,
2338 Err(FieldAccessError::OutOfRange { field_count }) => {
2342 "accessed field #{} but variant only has {}",
2349 let operand_ty = operand.ty(body, tcx);
2350 let operand_ty = self.normalize(operand_ty, location);
2352 if let Err(terr) = self.sub_types(
2355 location.to_locations(),
2356 ConstraintCategory::Boring,
2361 "{:?} is not a subtype of {:?}: {:?}",
2370 /// Adds the constraints that arise from a borrow expression `&'a P` at the location `L`.
2374 /// - `location`: the location `L` where the borrow expression occurs
2375 /// - `borrow_region`: the region `'a` associated with the borrow
2376 /// - `borrowed_place`: the place `P` being borrowed
2377 fn add_reborrow_constraint(
2381 borrow_region: ty::Region<'tcx>,
2382 borrowed_place: &Place<'tcx>,
2384 // These constraints are only meaningful during borrowck:
2385 let BorrowCheckContext { borrow_set, location_table, all_facts, constraints, .. } =
2386 self.borrowck_context;
2388 // In Polonius mode, we also push a `loan_issued_at` fact
2389 // linking the loan to the region (in some cases, though,
2390 // there is no loan associated with this borrow expression --
2391 // that occurs when we are borrowing an unsafe place, for
2393 if let Some(all_facts) = all_facts {
2394 let _prof_timer = self.infcx.tcx.prof.generic_activity("polonius_fact_generation");
2395 if let Some(borrow_index) = borrow_set.get_index_of(&location) {
2396 let region_vid = borrow_region.to_region_vid();
2397 all_facts.loan_issued_at.push((
2400 location_table.mid_index(location),
2405 // If we are reborrowing the referent of another reference, we
2406 // need to add outlives relationships. In a case like `&mut
2407 // *p`, where the `p` has type `&'b mut Foo`, for example, we
2408 // need to ensure that `'b: 'a`.
2411 "add_reborrow_constraint({:?}, {:?}, {:?})",
2412 location, borrow_region, borrowed_place
2415 let mut cursor = borrowed_place.projection.as_ref();
2416 let tcx = self.infcx.tcx;
2417 let field = path_utils::is_upvar_field_projection(
2419 &self.borrowck_context.upvars,
2420 borrowed_place.as_ref(),
2423 let category = if let Some(field) = field {
2424 ConstraintCategory::ClosureUpvar(field)
2426 ConstraintCategory::Boring
2429 while let [proj_base @ .., elem] = cursor {
2432 debug!("add_reborrow_constraint - iteration {:?}", elem);
2435 ProjectionElem::Deref => {
2436 let base_ty = Place::ty_from(borrowed_place.local, proj_base, body, tcx).ty;
2438 debug!("add_reborrow_constraint - base_ty = {:?}", base_ty);
2439 match base_ty.kind() {
2440 ty::Ref(ref_region, _, mutbl) => {
2441 constraints.outlives_constraints.push(OutlivesConstraint {
2442 sup: ref_region.to_region_vid(),
2443 sub: borrow_region.to_region_vid(),
2444 locations: location.to_locations(),
2445 span: location.to_locations().span(body),
2447 variance_info: ty::VarianceDiagInfo::default(),
2451 hir::Mutability::Not => {
2452 // Immutable reference. We don't need the base
2453 // to be valid for the entire lifetime of
2457 hir::Mutability::Mut => {
2458 // Mutable reference. We *do* need the base
2459 // to be valid, because after the base becomes
2460 // invalid, someone else can use our mutable deref.
2462 // This is in order to make the following function
2465 // fn unsafe_deref<'a, 'b>(x: &'a &'b mut T) -> &'b mut T {
2470 // As otherwise you could clone `&mut T` using the
2471 // following function:
2473 // fn bad(x: &mut T) -> (&mut T, &mut T) {
2474 // let my_clone = unsafe_deref(&'a x);
2483 // deref of raw pointer, guaranteed to be valid
2486 ty::Adt(def, _) if def.is_box() => {
2487 // deref of `Box`, need the base to be valid - propagate
2489 _ => bug!("unexpected deref ty {:?} in {:?}", base_ty, borrowed_place),
2492 ProjectionElem::Field(..)
2493 | ProjectionElem::Downcast(..)
2494 | ProjectionElem::Index(..)
2495 | ProjectionElem::ConstantIndex { .. }
2496 | ProjectionElem::Subslice { .. } => {
2497 // other field access
2503 fn prove_aggregate_predicates(
2505 aggregate_kind: &AggregateKind<'tcx>,
2508 let tcx = self.tcx();
2511 "prove_aggregate_predicates(aggregate_kind={:?}, location={:?})",
2512 aggregate_kind, location
2515 let (def_id, instantiated_predicates) = match aggregate_kind {
2516 AggregateKind::Adt(adt_did, _, substs, _, _) => {
2517 (*adt_did, tcx.predicates_of(*adt_did).instantiate(tcx, substs))
2520 // For closures, we have some **extra requirements** we
2522 // have to check. In particular, in their upvars and
2523 // signatures, closures often reference various regions
2524 // from the surrounding function -- we call those the
2525 // closure's free regions. When we borrow-check (and hence
2526 // region-check) closures, we may find that the closure
2527 // requires certain relationships between those free
2528 // regions. However, because those free regions refer to
2529 // portions of the CFG of their caller, the closure is not
2530 // in a position to verify those relationships. In that
2531 // case, the requirements get "propagated" to us, and so
2532 // we have to solve them here where we instantiate the
2535 // Despite the opacity of the previous paragraph, this is
2536 // actually relatively easy to understand in terms of the
2537 // desugaring. A closure gets desugared to a struct, and
2538 // these extra requirements are basically like where
2539 // clauses on the struct.
2540 AggregateKind::Closure(def_id, substs)
2541 | AggregateKind::Generator(def_id, substs, _) => {
2542 (*def_id, self.prove_closure_bounds(tcx, def_id.expect_local(), substs, location))
2545 AggregateKind::Array(_) | AggregateKind::Tuple => {
2546 (CRATE_DEF_ID.to_def_id(), ty::InstantiatedPredicates::empty())
2550 self.normalize_and_prove_instantiated_predicates(
2552 instantiated_predicates,
2553 location.to_locations(),
2557 fn prove_closure_bounds(
2561 substs: SubstsRef<'tcx>,
2563 ) -> ty::InstantiatedPredicates<'tcx> {
2564 if let Some(ref closure_region_requirements) = tcx.mir_borrowck(def_id).closure_requirements
2566 let closure_constraints = QueryRegionConstraints {
2567 outlives: closure_region_requirements.apply_requirements(
2573 // Presently, closures never propagate member
2574 // constraints to their parents -- they are enforced
2575 // locally. This is largely a non-issue as member
2576 // constraints only come from `-> impl Trait` and
2577 // friends which don't appear (thus far...) in
2579 member_constraints: vec![],
2582 let bounds_mapping = closure_constraints
2586 .filter_map(|(idx, constraint)| {
2587 let ty::OutlivesPredicate(k1, r2) =
2588 constraint.no_bound_vars().unwrap_or_else(|| {
2589 bug!("query_constraint {:?} contained bound vars", constraint,);
2593 GenericArgKind::Lifetime(r1) => {
2594 // constraint is r1: r2
2595 let r1_vid = self.borrowck_context.universal_regions.to_region_vid(r1);
2596 let r2_vid = self.borrowck_context.universal_regions.to_region_vid(r2);
2597 let outlives_requirements =
2598 &closure_region_requirements.outlives_requirements[idx];
2601 (outlives_requirements.category, outlives_requirements.blame_span),
2604 GenericArgKind::Type(_) | GenericArgKind::Const(_) => None,
2612 .closure_bounds_mapping
2613 .insert(location, bounds_mapping);
2614 assert!(existing.is_none(), "Multiple closures at the same location.");
2616 self.push_region_constraints(
2617 location.to_locations(),
2618 ConstraintCategory::ClosureBounds,
2619 &closure_constraints,
2623 tcx.predicates_of(def_id).instantiate(tcx, substs)
2626 #[instrument(skip(self, body), level = "debug")]
2627 fn typeck_mir(&mut self, body: &Body<'tcx>) {
2628 self.last_span = body.span;
2631 for (local, local_decl) in body.local_decls.iter_enumerated() {
2632 self.check_local(&body, local, local_decl);
2635 for (block, block_data) in body.basic_blocks().iter_enumerated() {
2636 let mut location = Location { block, statement_index: 0 };
2637 for stmt in &block_data.statements {
2638 if !stmt.source_info.span.is_dummy() {
2639 self.last_span = stmt.source_info.span;
2641 self.check_stmt(body, stmt, location);
2642 location.statement_index += 1;
2645 self.check_terminator(&body, block_data.terminator(), location);
2646 self.check_iscleanup(&body, block_data);
2651 trait NormalizeLocation: fmt::Debug + Copy {
2652 fn to_locations(self) -> Locations;
2655 impl NormalizeLocation for Locations {
2656 fn to_locations(self) -> Locations {
2661 impl NormalizeLocation for Location {
2662 fn to_locations(self) -> Locations {
2663 Locations::Single(self)
2667 /// Runs `infcx.instantiate_opaque_types`. Unlike other `TypeOp`s,
2668 /// this is not canonicalized - it directly affects the main `InferCtxt`
2669 /// that we use during MIR borrowchecking.
2671 pub(super) struct InstantiateOpaqueType<'tcx> {
2672 pub base_universe: Option<ty::UniverseIndex>,
2673 pub region_constraints: Option<RegionConstraintData<'tcx>>,
2674 pub obligations: Vec<PredicateObligation<'tcx>>,
2677 impl<'tcx> TypeOp<'tcx> for InstantiateOpaqueType<'tcx> {
2679 /// We use this type itself to store the information used
2680 /// when reporting errors. Since this is not a query, we don't
2681 /// re-run anything during error reporting - we just use the information
2682 /// we saved to help extract an error from the already-existing region
2683 /// constraints in our `InferCtxt`
2684 type ErrorInfo = InstantiateOpaqueType<'tcx>;
2686 fn fully_perform(mut self, infcx: &InferCtxt<'_, 'tcx>) -> Fallible<TypeOpOutput<'tcx, Self>> {
2687 let (mut output, region_constraints) = scrape_region_constraints(infcx, || {
2688 Ok(InferOk { value: (), obligations: self.obligations.clone() })
2690 self.region_constraints = Some(region_constraints);
2691 output.error_info = Some(self);