1 // Type resolution: the phase that finds all the types in the AST with
2 // unresolved type variables and replaces "ty_var" types with their
6 use hir::def_id::LocalDefId;
7 use rustc_data_structures::fx::FxHashMap;
8 use rustc_errors::ErrorGuaranteed;
10 use rustc_hir::intravisit::{self, Visitor};
11 use rustc_infer::infer::error_reporting::TypeAnnotationNeeded::E0282;
12 use rustc_infer::infer::InferCtxt;
13 use rustc_middle::hir::place::Place as HirPlace;
14 use rustc_middle::mir::FakeReadCause;
15 use rustc_middle::ty::adjustment::{Adjust, Adjustment, PointerCast};
16 use rustc_middle::ty::fold::{TypeFoldable, TypeFolder, TypeSuperFoldable};
17 use rustc_middle::ty::visit::{TypeSuperVisitable, TypeVisitable};
18 use rustc_middle::ty::TypeckResults;
19 use rustc_middle::ty::{self, ClosureSizeProfileData, Ty, TyCtxt};
20 use rustc_span::symbol::sym;
24 use std::ops::ControlFlow;
26 ///////////////////////////////////////////////////////////////////////////
29 // During type inference, partially inferred types are
30 // represented using Type variables (ty::Infer). These don't appear in
31 // the final TypeckResults since all of the types should have been
32 // inferred once typeck is done.
33 // When type inference is running however, having to update the typeck
34 // typeck results every time a new type is inferred would be unreasonably slow,
35 // so instead all of the replacement happens at the end in
36 // resolve_type_vars_in_body, which creates a new TypeTables which
37 // doesn't contain any inference types.
38 impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
39 pub fn resolve_type_vars_in_body(
41 body: &'tcx hir::Body<'tcx>,
42 ) -> &'tcx ty::TypeckResults<'tcx> {
43 let item_id = self.tcx.hir().body_owner(body.id());
44 let item_def_id = self.tcx.hir().local_def_id(item_id);
46 // This attribute causes us to dump some writeback information
47 // in the form of errors, which is used for unit tests.
48 let rustc_dump_user_substs =
49 self.tcx.has_attr(item_def_id.to_def_id(), sym::rustc_dump_user_substs);
51 let mut wbcx = WritebackCx::new(self, body, rustc_dump_user_substs);
52 for param in body.params {
53 wbcx.visit_node_id(param.pat.span, param.hir_id);
55 // Type only exists for constants and statics, not functions.
56 match self.tcx.hir().body_owner_kind(item_def_id) {
57 hir::BodyOwnerKind::Const | hir::BodyOwnerKind::Static(_) => {
58 wbcx.visit_node_id(body.value.span, item_id);
60 hir::BodyOwnerKind::Closure | hir::BodyOwnerKind::Fn => (),
62 wbcx.visit_body(body);
63 wbcx.visit_min_capture_map();
64 wbcx.eval_closure_size();
65 wbcx.visit_fake_reads_map();
66 wbcx.visit_closures();
67 wbcx.visit_liberated_fn_sigs();
68 wbcx.visit_fru_field_types();
69 wbcx.visit_opaque_types();
70 wbcx.visit_coercion_casts();
71 wbcx.visit_user_provided_tys();
72 wbcx.visit_user_provided_sigs();
73 wbcx.visit_generator_interior_types();
75 wbcx.typeck_results.rvalue_scopes =
76 mem::take(&mut self.typeck_results.borrow_mut().rvalue_scopes);
78 let used_trait_imports =
79 mem::take(&mut self.typeck_results.borrow_mut().used_trait_imports);
80 debug!("used_trait_imports({:?}) = {:?}", item_def_id, used_trait_imports);
81 wbcx.typeck_results.used_trait_imports = used_trait_imports;
83 wbcx.typeck_results.treat_byte_string_as_slice =
84 mem::take(&mut self.typeck_results.borrow_mut().treat_byte_string_as_slice);
86 if self.is_tainted_by_errors() {
87 // FIXME(eddyb) keep track of `ErrorGuaranteed` from where the error was emitted.
88 wbcx.typeck_results.tainted_by_errors =
89 Some(ErrorGuaranteed::unchecked_claim_error_was_emitted());
92 debug!("writeback: typeck results for {:?} are {:#?}", item_def_id, wbcx.typeck_results);
94 self.tcx.arena.alloc(wbcx.typeck_results)
98 ///////////////////////////////////////////////////////////////////////////
99 // The Writeback context. This visitor walks the HIR, checking the
100 // fn-specific typeck results to find references to types or regions. It
101 // resolves those regions to remove inference variables and writes the
102 // final result back into the master typeck results in the tcx. Here and
103 // there, it applies a few ad-hoc checks that were not convenient to
106 struct WritebackCx<'cx, 'tcx> {
107 fcx: &'cx FnCtxt<'cx, 'tcx>,
109 typeck_results: ty::TypeckResults<'tcx>,
111 body: &'tcx hir::Body<'tcx>,
113 rustc_dump_user_substs: bool,
116 impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> {
118 fcx: &'cx FnCtxt<'cx, 'tcx>,
119 body: &'tcx hir::Body<'tcx>,
120 rustc_dump_user_substs: bool,
121 ) -> WritebackCx<'cx, 'tcx> {
122 let owner = body.id().hir_id.owner;
126 typeck_results: ty::TypeckResults::new(owner),
128 rustc_dump_user_substs,
132 fn tcx(&self) -> TyCtxt<'tcx> {
136 fn write_ty_to_typeck_results(&mut self, hir_id: hir::HirId, ty: Ty<'tcx>) {
137 debug!("write_ty_to_typeck_results({:?}, {:?})", hir_id, ty);
138 assert!(!ty.needs_infer() && !ty.has_placeholders() && !ty.has_free_regions());
139 self.typeck_results.node_types_mut().insert(hir_id, ty);
142 // Hacky hack: During type-checking, we treat *all* operators
143 // as potentially overloaded. But then, during writeback, if
144 // we observe that something like `a+b` is (known to be)
145 // operating on scalars, we clear the overload.
146 fn fix_scalar_builtin_expr(&mut self, e: &hir::Expr<'_>) {
148 hir::ExprKind::Unary(hir::UnOp::Neg | hir::UnOp::Not, inner) => {
149 let inner_ty = self.fcx.node_ty(inner.hir_id);
150 let inner_ty = self.fcx.resolve_vars_if_possible(inner_ty);
152 if inner_ty.is_scalar() {
153 let mut typeck_results = self.fcx.typeck_results.borrow_mut();
154 typeck_results.type_dependent_defs_mut().remove(e.hir_id);
155 typeck_results.node_substs_mut().remove(e.hir_id);
158 hir::ExprKind::Binary(ref op, lhs, rhs) | hir::ExprKind::AssignOp(ref op, lhs, rhs) => {
159 let lhs_ty = self.fcx.node_ty(lhs.hir_id);
160 let lhs_ty = self.fcx.resolve_vars_if_possible(lhs_ty);
162 let rhs_ty = self.fcx.node_ty(rhs.hir_id);
163 let rhs_ty = self.fcx.resolve_vars_if_possible(rhs_ty);
165 if lhs_ty.is_scalar() && rhs_ty.is_scalar() {
166 let mut typeck_results = self.fcx.typeck_results.borrow_mut();
167 typeck_results.type_dependent_defs_mut().remove(e.hir_id);
168 typeck_results.node_substs_mut().remove(e.hir_id);
171 hir::ExprKind::Binary(..) => {
172 if !op.node.is_by_value() {
173 let mut adjustments = typeck_results.adjustments_mut();
174 if let Some(a) = adjustments.get_mut(lhs.hir_id) {
177 if let Some(a) = adjustments.get_mut(rhs.hir_id) {
182 hir::ExprKind::AssignOp(..)
183 if let Some(a) = typeck_results.adjustments_mut().get_mut(lhs.hir_id) =>
195 // (ouz-a 1005988): Normally `[T] : std::ops::Index<usize>` should be normalized
196 // into [T] but currently `Where` clause stops the normalization process for it,
197 // here we compare types of expr and base in a code without `Where` clause they would be equal
198 // if they are not we don't modify the expr, hence we bypass the ICE
201 typeck_results: &TypeckResults<'tcx>,
206 if let Some(elem_ty) = base_ty.builtin_index() {
207 let Some(exp_ty) = typeck_results.expr_ty_opt(e) else {return false;};
208 let resolved_exp_ty = self.resolve(exp_ty, &e.span);
210 elem_ty == resolved_exp_ty && index_ty == self.fcx.tcx.types.usize
216 // Similar to operators, indexing is always assumed to be overloaded
217 // Here, correct cases where an indexing expression can be simplified
218 // to use builtin indexing because the index type is known to be
220 fn fix_index_builtin_expr(&mut self, e: &hir::Expr<'_>) {
221 if let hir::ExprKind::Index(ref base, ref index) = e.kind {
222 let mut typeck_results = self.fcx.typeck_results.borrow_mut();
224 // All valid indexing looks like this; might encounter non-valid indexes at this point.
225 let base_ty = typeck_results
226 .expr_ty_adjusted_opt(base)
227 .map(|t| self.fcx.resolve_vars_if_possible(t).kind());
228 if base_ty.is_none() {
229 // When encountering `return [0][0]` outside of a `fn` body we can encounter a base
230 // that isn't in the type table. We assume more relevant errors have already been
231 // emitted, so we delay an ICE if none have. (#64638)
232 self.tcx().sess.delay_span_bug(e.span, &format!("bad base: `{:?}`", base));
234 if let Some(ty::Ref(_, base_ty, _)) = base_ty {
235 let index_ty = typeck_results.expr_ty_adjusted_opt(index).unwrap_or_else(|| {
236 // When encountering `return [0][0]` outside of a `fn` body we would attempt
237 // to access an nonexistent index. We assume that more relevant errors will
238 // already have been emitted, so we only gate on this with an ICE if no
239 // error has been emitted. (#64638)
240 self.fcx.tcx.ty_error_with_message(
242 &format!("bad index {:?} for base: `{:?}`", index, base),
245 let index_ty = self.fcx.resolve_vars_if_possible(index_ty);
246 let resolved_base_ty = self.resolve(*base_ty, &base.span);
248 if self.is_builtin_index(&typeck_results, e, resolved_base_ty, index_ty) {
249 // Remove the method call record
250 typeck_results.type_dependent_defs_mut().remove(e.hir_id);
251 typeck_results.node_substs_mut().remove(e.hir_id);
253 if let Some(a) = typeck_results.adjustments_mut().get_mut(base.hir_id) {
254 // Discard the need for a mutable borrow
256 // Extra adjustment made when indexing causes a drop
257 // of size information - we need to get rid of it
258 // Since this is "after" the other adjustment to be
259 // discarded, we do an extra `pop()`
260 if let Some(Adjustment {
261 kind: Adjust::Pointer(PointerCast::Unsize), ..
264 // So the borrow discard actually happens here
274 ///////////////////////////////////////////////////////////////////////////
275 // Impl of Visitor for Resolver
277 // This is the master code which walks the AST. It delegates most of
278 // the heavy lifting to the generic visit and resolve functions
279 // below. In general, a function is made into a `visitor` if it must
280 // traffic in node-ids or update typeck results in the type context etc.
282 impl<'cx, 'tcx> Visitor<'tcx> for WritebackCx<'cx, 'tcx> {
283 fn visit_expr(&mut self, e: &'tcx hir::Expr<'tcx>) {
284 self.fix_scalar_builtin_expr(e);
285 self.fix_index_builtin_expr(e);
288 hir::ExprKind::Closure(&hir::Closure { body, .. }) => {
289 let body = self.fcx.tcx.hir().body(body);
290 for param in body.params {
291 self.visit_node_id(e.span, param.hir_id);
294 self.visit_body(body);
296 hir::ExprKind::Struct(_, fields, _) => {
297 for field in fields {
298 self.visit_field_id(field.hir_id);
301 hir::ExprKind::Field(..) => {
302 self.visit_field_id(e.hir_id);
304 hir::ExprKind::ConstBlock(anon_const) => {
305 self.visit_node_id(e.span, anon_const.hir_id);
307 let body = self.tcx().hir().body(anon_const.body);
308 self.visit_body(body);
313 self.visit_node_id(e.span, e.hir_id);
314 intravisit::walk_expr(self, e);
317 fn visit_generic_param(&mut self, p: &'tcx hir::GenericParam<'tcx>) {
319 hir::GenericParamKind::Lifetime { .. } => {
320 // Nothing to write back here
322 hir::GenericParamKind::Type { .. } | hir::GenericParamKind::Const { .. } => {
323 self.tcx().sess.delay_span_bug(p.span, format!("unexpected generic param: {p:?}"));
328 fn visit_block(&mut self, b: &'tcx hir::Block<'tcx>) {
329 self.visit_node_id(b.span, b.hir_id);
330 intravisit::walk_block(self, b);
333 fn visit_pat(&mut self, p: &'tcx hir::Pat<'tcx>) {
335 hir::PatKind::Binding(..) => {
336 let typeck_results = self.fcx.typeck_results.borrow();
338 typeck_results.extract_binding_mode(self.tcx().sess, p.hir_id, p.span)
340 self.typeck_results.pat_binding_modes_mut().insert(p.hir_id, bm);
343 hir::PatKind::Struct(_, fields, _) => {
344 for field in fields {
345 self.visit_field_id(field.hir_id);
351 self.visit_pat_adjustments(p.span, p.hir_id);
353 self.visit_node_id(p.span, p.hir_id);
354 intravisit::walk_pat(self, p);
357 fn visit_local(&mut self, l: &'tcx hir::Local<'tcx>) {
358 intravisit::walk_local(self, l);
359 let var_ty = self.fcx.local_ty(l.span, l.hir_id).decl_ty;
360 let var_ty = self.resolve(var_ty, &l.span);
361 self.write_ty_to_typeck_results(l.hir_id, var_ty);
364 fn visit_ty(&mut self, hir_ty: &'tcx hir::Ty<'tcx>) {
365 intravisit::walk_ty(self, hir_ty);
366 let ty = self.fcx.node_ty(hir_ty.hir_id);
367 let ty = self.resolve(ty, &hir_ty.span);
368 self.write_ty_to_typeck_results(hir_ty.hir_id, ty);
371 fn visit_infer(&mut self, inf: &'tcx hir::InferArg) {
372 intravisit::walk_inf(self, inf);
373 // Ignore cases where the inference is a const.
374 if let Some(ty) = self.fcx.node_ty_opt(inf.hir_id) {
375 let ty = self.resolve(ty, &inf.span);
376 self.write_ty_to_typeck_results(inf.hir_id, ty);
381 impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> {
382 fn eval_closure_size(&mut self) {
383 let mut res: FxHashMap<LocalDefId, ClosureSizeProfileData<'tcx>> = Default::default();
384 for (&closure_def_id, data) in self.fcx.typeck_results.borrow().closure_size_eval.iter() {
385 let closure_hir_id = self.tcx().hir().local_def_id_to_hir_id(closure_def_id);
387 let data = self.resolve(*data, &closure_hir_id);
389 res.insert(closure_def_id, data);
392 self.typeck_results.closure_size_eval = res;
394 fn visit_min_capture_map(&mut self) {
395 let mut min_captures_wb = ty::MinCaptureInformationMap::with_capacity_and_hasher(
396 self.fcx.typeck_results.borrow().closure_min_captures.len(),
399 for (&closure_def_id, root_min_captures) in
400 self.fcx.typeck_results.borrow().closure_min_captures.iter()
402 let mut root_var_map_wb = ty::RootVariableMinCaptureList::with_capacity_and_hasher(
403 root_min_captures.len(),
406 for (var_hir_id, min_list) in root_min_captures.iter() {
407 let min_list_wb = min_list
409 .map(|captured_place| {
410 let locatable = captured_place.info.path_expr_id.unwrap_or_else(|| {
411 self.tcx().hir().local_def_id_to_hir_id(closure_def_id)
414 self.resolve(captured_place.clone(), &locatable)
417 root_var_map_wb.insert(*var_hir_id, min_list_wb);
419 min_captures_wb.insert(closure_def_id, root_var_map_wb);
422 self.typeck_results.closure_min_captures = min_captures_wb;
425 fn visit_fake_reads_map(&mut self) {
426 let mut resolved_closure_fake_reads: FxHashMap<
428 Vec<(HirPlace<'tcx>, FakeReadCause, hir::HirId)>,
429 > = Default::default();
430 for (&closure_def_id, fake_reads) in
431 self.fcx.typeck_results.borrow().closure_fake_reads.iter()
433 let mut resolved_fake_reads = Vec::<(HirPlace<'tcx>, FakeReadCause, hir::HirId)>::new();
434 for (place, cause, hir_id) in fake_reads.iter() {
435 let locatable = self.tcx().hir().local_def_id_to_hir_id(closure_def_id);
437 let resolved_fake_read = self.resolve(place.clone(), &locatable);
438 resolved_fake_reads.push((resolved_fake_read, *cause, *hir_id));
440 resolved_closure_fake_reads.insert(closure_def_id, resolved_fake_reads);
442 self.typeck_results.closure_fake_reads = resolved_closure_fake_reads;
445 fn visit_closures(&mut self) {
446 let fcx_typeck_results = self.fcx.typeck_results.borrow();
447 assert_eq!(fcx_typeck_results.hir_owner, self.typeck_results.hir_owner);
448 let common_hir_owner = fcx_typeck_results.hir_owner;
450 for (id, origin) in fcx_typeck_results.closure_kind_origins().iter() {
451 let hir_id = hir::HirId { owner: common_hir_owner, local_id: *id };
452 let place_span = origin.0;
453 let place = self.resolve(origin.1.clone(), &place_span);
454 self.typeck_results.closure_kind_origins_mut().insert(hir_id, (place_span, place));
458 fn visit_coercion_casts(&mut self) {
459 let fcx_typeck_results = self.fcx.typeck_results.borrow();
460 let fcx_coercion_casts = fcx_typeck_results.coercion_casts();
461 assert_eq!(fcx_typeck_results.hir_owner, self.typeck_results.hir_owner);
463 for local_id in fcx_coercion_casts {
464 self.typeck_results.set_coercion_cast(*local_id);
468 fn visit_user_provided_tys(&mut self) {
469 let fcx_typeck_results = self.fcx.typeck_results.borrow();
470 assert_eq!(fcx_typeck_results.hir_owner, self.typeck_results.hir_owner);
471 let common_hir_owner = fcx_typeck_results.hir_owner;
473 let mut errors_buffer = Vec::new();
474 for (&local_id, c_ty) in fcx_typeck_results.user_provided_types().iter() {
475 let hir_id = hir::HirId { owner: common_hir_owner, local_id };
477 if cfg!(debug_assertions) && c_ty.needs_infer() {
479 hir_id.to_span(self.fcx.tcx),
480 "writeback: `{:?}` has inference variables",
485 self.typeck_results.user_provided_types_mut().insert(hir_id, *c_ty);
487 if let ty::UserType::TypeOf(_, user_substs) = c_ty.value {
488 if self.rustc_dump_user_substs {
489 // This is a unit-testing mechanism.
490 let span = self.tcx().hir().span(hir_id);
491 // We need to buffer the errors in order to guarantee a consistent
492 // order when emitting them.
496 .struct_span_err(span, &format!("user substs: {:?}", user_substs));
497 err.buffer(&mut errors_buffer);
502 if !errors_buffer.is_empty() {
503 errors_buffer.sort_by_key(|diag| diag.span.primary_span());
504 for mut diag in errors_buffer {
505 self.tcx().sess.diagnostic().emit_diagnostic(&mut diag);
510 fn visit_user_provided_sigs(&mut self) {
511 let fcx_typeck_results = self.fcx.typeck_results.borrow();
512 assert_eq!(fcx_typeck_results.hir_owner, self.typeck_results.hir_owner);
514 for (&def_id, c_sig) in fcx_typeck_results.user_provided_sigs.iter() {
515 if cfg!(debug_assertions) && c_sig.needs_infer() {
517 self.fcx.tcx.def_span(def_id),
518 "writeback: `{:?}` has inference variables",
523 self.typeck_results.user_provided_sigs.insert(def_id, *c_sig);
527 fn visit_generator_interior_types(&mut self) {
528 let fcx_typeck_results = self.fcx.typeck_results.borrow();
529 assert_eq!(fcx_typeck_results.hir_owner, self.typeck_results.hir_owner);
530 self.typeck_results.generator_interior_types =
531 fcx_typeck_results.generator_interior_types.clone();
534 #[instrument(skip(self), level = "debug")]
535 fn visit_opaque_types(&mut self) {
537 self.fcx.infcx.inner.borrow_mut().opaque_type_storage.take_opaque_types();
538 for (opaque_type_key, decl) in opaque_types {
539 let hidden_type = self.resolve(decl.hidden_type, &decl.hidden_type.span);
540 let opaque_type_key = self.resolve(opaque_type_key, &decl.hidden_type.span);
542 struct RecursionChecker {
545 impl<'tcx> ty::TypeVisitor<'tcx> for RecursionChecker {
547 fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
548 if let ty::Opaque(def_id, _) = *t.kind() {
549 if def_id == self.def_id.to_def_id() {
550 return ControlFlow::Break(());
553 t.super_visit_with(self)
557 .visit_with(&mut RecursionChecker { def_id: opaque_type_key.def_id })
563 let hidden_type = hidden_type.remap_generic_params_to_declaration_params(
570 self.typeck_results.concrete_opaque_types.insert(opaque_type_key.def_id, hidden_type);
574 fn visit_field_id(&mut self, hir_id: hir::HirId) {
575 if let Some(index) = self.fcx.typeck_results.borrow_mut().field_indices_mut().remove(hir_id)
577 self.typeck_results.field_indices_mut().insert(hir_id, index);
581 #[instrument(skip(self, span), level = "debug")]
582 fn visit_node_id(&mut self, span: Span, hir_id: hir::HirId) {
583 // Export associated path extensions and method resolutions.
585 self.fcx.typeck_results.borrow_mut().type_dependent_defs_mut().remove(hir_id)
587 self.typeck_results.type_dependent_defs_mut().insert(hir_id, def);
590 // Resolve any borrowings for the node with id `node_id`
591 self.visit_adjustments(span, hir_id);
593 // Resolve the type of the node with id `node_id`
594 let n_ty = self.fcx.node_ty(hir_id);
595 let n_ty = self.resolve(n_ty, &span);
596 self.write_ty_to_typeck_results(hir_id, n_ty);
599 // Resolve any substitutions
600 if let Some(substs) = self.fcx.typeck_results.borrow().node_substs_opt(hir_id) {
601 let substs = self.resolve(substs, &span);
602 debug!("write_substs_to_tcx({:?}, {:?})", hir_id, substs);
603 assert!(!substs.needs_infer() && !substs.has_placeholders());
604 self.typeck_results.node_substs_mut().insert(hir_id, substs);
608 #[instrument(skip(self, span), level = "debug")]
609 fn visit_adjustments(&mut self, span: Span, hir_id: hir::HirId) {
610 let adjustment = self.fcx.typeck_results.borrow_mut().adjustments_mut().remove(hir_id);
613 debug!("no adjustments for node");
616 Some(adjustment) => {
617 let resolved_adjustment = self.resolve(adjustment, &span);
618 debug!(?resolved_adjustment);
619 self.typeck_results.adjustments_mut().insert(hir_id, resolved_adjustment);
624 #[instrument(skip(self, span), level = "debug")]
625 fn visit_pat_adjustments(&mut self, span: Span, hir_id: hir::HirId) {
626 let adjustment = self.fcx.typeck_results.borrow_mut().pat_adjustments_mut().remove(hir_id);
629 debug!("no pat_adjustments for node");
632 Some(adjustment) => {
633 let resolved_adjustment = self.resolve(adjustment, &span);
634 debug!(?resolved_adjustment);
635 self.typeck_results.pat_adjustments_mut().insert(hir_id, resolved_adjustment);
640 fn visit_liberated_fn_sigs(&mut self) {
641 let fcx_typeck_results = self.fcx.typeck_results.borrow();
642 assert_eq!(fcx_typeck_results.hir_owner, self.typeck_results.hir_owner);
643 let common_hir_owner = fcx_typeck_results.hir_owner;
645 for (&local_id, &fn_sig) in fcx_typeck_results.liberated_fn_sigs().iter() {
646 let hir_id = hir::HirId { owner: common_hir_owner, local_id };
647 let fn_sig = self.resolve(fn_sig, &hir_id);
648 self.typeck_results.liberated_fn_sigs_mut().insert(hir_id, fn_sig);
652 fn visit_fru_field_types(&mut self) {
653 let fcx_typeck_results = self.fcx.typeck_results.borrow();
654 assert_eq!(fcx_typeck_results.hir_owner, self.typeck_results.hir_owner);
655 let common_hir_owner = fcx_typeck_results.hir_owner;
657 for (&local_id, ftys) in fcx_typeck_results.fru_field_types().iter() {
658 let hir_id = hir::HirId { owner: common_hir_owner, local_id };
659 let ftys = self.resolve(ftys.clone(), &hir_id);
660 self.typeck_results.fru_field_types_mut().insert(hir_id, ftys);
664 fn resolve<T>(&mut self, x: T, span: &dyn Locatable) -> T
666 T: TypeFoldable<'tcx>,
668 let mut resolver = Resolver::new(self.fcx, span, self.body);
669 let x = x.fold_with(&mut resolver);
670 if cfg!(debug_assertions) && x.needs_infer() {
671 span_bug!(span.to_span(self.fcx.tcx), "writeback: `{:?}` has inference variables", x);
674 // We may have introduced e.g. `ty::Error`, if inference failed, make sure
675 // to mark the `TypeckResults` as tainted in that case, so that downstream
676 // users of the typeck results don't produce extra errors, or worse, ICEs.
677 if resolver.replaced_with_error {
678 // FIXME(eddyb) keep track of `ErrorGuaranteed` from where the error was emitted.
679 self.typeck_results.tainted_by_errors =
680 Some(ErrorGuaranteed::unchecked_claim_error_was_emitted());
687 pub(crate) trait Locatable {
688 fn to_span(&self, tcx: TyCtxt<'_>) -> Span;
691 impl Locatable for Span {
692 fn to_span(&self, _: TyCtxt<'_>) -> Span {
697 impl Locatable for hir::HirId {
698 fn to_span(&self, tcx: TyCtxt<'_>) -> Span {
699 tcx.hir().span(*self)
703 /// The Resolver. This is the type folding engine that detects
704 /// unresolved types and so forth.
705 struct Resolver<'cx, 'tcx> {
707 infcx: &'cx InferCtxt<'tcx>,
708 span: &'cx dyn Locatable,
709 body: &'tcx hir::Body<'tcx>,
711 /// Set to `true` if any `Ty` or `ty::Const` had to be replaced with an `Error`.
712 replaced_with_error: bool,
715 impl<'cx, 'tcx> Resolver<'cx, 'tcx> {
717 fcx: &'cx FnCtxt<'cx, 'tcx>,
718 span: &'cx dyn Locatable,
719 body: &'tcx hir::Body<'tcx>,
720 ) -> Resolver<'cx, 'tcx> {
721 Resolver { tcx: fcx.tcx, infcx: fcx, span, body, replaced_with_error: false }
724 fn report_error(&self, p: impl Into<ty::GenericArg<'tcx>>) {
725 if !self.tcx.sess.has_errors().is_some() {
728 .emit_inference_failure_err(
729 Some(self.body.id()),
730 self.span.to_span(self.tcx),
740 struct EraseEarlyRegions<'tcx> {
744 impl<'tcx> TypeFolder<'tcx> for EraseEarlyRegions<'tcx> {
745 fn tcx<'b>(&'b self) -> TyCtxt<'tcx> {
748 fn fold_ty(&mut self, ty: Ty<'tcx>) -> Ty<'tcx> {
749 if ty.has_type_flags(ty::TypeFlags::HAS_FREE_REGIONS) {
750 ty.super_fold_with(self)
755 fn fold_region(&mut self, r: ty::Region<'tcx>) -> ty::Region<'tcx> {
756 if r.is_late_bound() { r } else { self.tcx.lifetimes.re_erased }
760 impl<'cx, 'tcx> TypeFolder<'tcx> for Resolver<'cx, 'tcx> {
761 fn tcx<'a>(&'a self) -> TyCtxt<'tcx> {
765 fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> {
766 match self.infcx.fully_resolve(t) {
768 // Do not anonymize late-bound regions
769 // (e.g. keep `for<'a>` named `for<'a>`).
770 // This allows NLL to generate error messages that
771 // refer to the higher-ranked lifetime names written by the user.
772 EraseEarlyRegions { tcx: self.tcx }.fold_ty(t)
775 debug!("Resolver::fold_ty: input type `{:?}` not fully resolvable", t);
776 self.report_error(t);
777 self.replaced_with_error = true;
778 self.tcx().ty_error()
783 fn fold_region(&mut self, r: ty::Region<'tcx>) -> ty::Region<'tcx> {
784 debug_assert!(!r.is_late_bound(), "Should not be resolving bound region.");
785 self.tcx.lifetimes.re_erased
788 fn fold_const(&mut self, ct: ty::Const<'tcx>) -> ty::Const<'tcx> {
789 match self.infcx.fully_resolve(ct) {
790 Ok(ct) => self.tcx.erase_regions(ct),
792 debug!("Resolver::fold_const: input const `{:?}` not fully resolvable", ct);
793 self.report_error(ct);
794 self.replaced_with_error = true;
795 self.tcx().const_error(ct.ty())
801 ///////////////////////////////////////////////////////////////////////////
802 // During type check, we store promises with the result of trait
803 // lookup rather than the actual results (because the results are not
804 // necessarily available immediately). These routines unwind the
805 // promises. It is expected that we will have already reported any
806 // errors that may be encountered, so if the promises store an error,
807 // a dummy result is returned.