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
5 use crate::check::FnCtxt;
7 use rustc_errors::ErrorReported;
9 use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
10 use rustc_infer::infer::error_reporting::TypeAnnotationNeeded::E0282;
11 use rustc_infer::infer::InferCtxt;
12 use rustc_middle::ty::adjustment::{Adjust, Adjustment, PointerCast};
13 use rustc_middle::ty::fold::{TypeFoldable, TypeFolder};
14 use rustc_middle::ty::{self, Ty, TyCtxt};
15 use rustc_span::symbol::sym;
17 use rustc_trait_selection::opaque_types::InferCtxtExt;
21 ///////////////////////////////////////////////////////////////////////////
24 // During type inference, partially inferred types are
25 // represented using Type variables (ty::Infer). These don't appear in
26 // the final TypeckResults since all of the types should have been
27 // inferred once typeck is done.
28 // When type inference is running however, having to update the typeck
29 // typeck results every time a new type is inferred would be unreasonably slow,
30 // so instead all of the replacement happens at the end in
31 // resolve_type_vars_in_body, which creates a new TypeTables which
32 // doesn't contain any inference types.
33 impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
34 pub fn resolve_type_vars_in_body(
36 body: &'tcx hir::Body<'tcx>,
37 ) -> &'tcx ty::TypeckResults<'tcx> {
38 let item_id = self.tcx.hir().body_owner(body.id());
39 let item_def_id = self.tcx.hir().local_def_id(item_id);
41 // This attribute causes us to dump some writeback information
42 // in the form of errors, which is uSymbol for unit tests.
43 let rustc_dump_user_substs =
44 self.tcx.has_attr(item_def_id.to_def_id(), sym::rustc_dump_user_substs);
46 let mut wbcx = WritebackCx::new(self, body, rustc_dump_user_substs);
47 for param in body.params {
48 wbcx.visit_node_id(param.pat.span, param.hir_id);
50 // Type only exists for constants and statics, not functions.
51 match self.tcx.hir().body_owner_kind(item_id) {
52 hir::BodyOwnerKind::Const | hir::BodyOwnerKind::Static(_) => {
53 wbcx.visit_node_id(body.value.span, item_id);
55 hir::BodyOwnerKind::Closure | hir::BodyOwnerKind::Fn => (),
57 wbcx.visit_body(body);
58 wbcx.visit_min_capture_map();
59 wbcx.visit_upvar_capture_map();
60 wbcx.visit_closures();
61 wbcx.visit_liberated_fn_sigs();
62 wbcx.visit_fru_field_types();
63 wbcx.visit_opaque_types(body.value.span);
64 wbcx.visit_coercion_casts();
65 wbcx.visit_user_provided_tys();
66 wbcx.visit_user_provided_sigs();
67 wbcx.visit_generator_interior_types();
69 let used_trait_imports =
70 mem::take(&mut self.typeck_results.borrow_mut().used_trait_imports);
71 debug!("used_trait_imports({:?}) = {:?}", item_def_id, used_trait_imports);
72 wbcx.typeck_results.used_trait_imports = used_trait_imports;
74 wbcx.typeck_results.treat_byte_string_as_slice =
75 mem::take(&mut self.typeck_results.borrow_mut().treat_byte_string_as_slice);
77 wbcx.typeck_results.closure_captures =
78 mem::take(&mut self.typeck_results.borrow_mut().closure_captures);
80 if self.is_tainted_by_errors() {
81 // FIXME(eddyb) keep track of `ErrorReported` from where the error was emitted.
82 wbcx.typeck_results.tainted_by_errors = Some(ErrorReported);
85 debug!("writeback: typeck results for {:?} are {:#?}", item_def_id, wbcx.typeck_results);
87 self.tcx.arena.alloc(wbcx.typeck_results)
91 ///////////////////////////////////////////////////////////////////////////
92 // The Writeback context. This visitor walks the HIR, checking the
93 // fn-specific typeck results to find references to types or regions. It
94 // resolves those regions to remove inference variables and writes the
95 // final result back into the master typeck results in the tcx. Here and
96 // there, it applies a few ad-hoc checks that were not convenient to
99 struct WritebackCx<'cx, 'tcx> {
100 fcx: &'cx FnCtxt<'cx, 'tcx>,
102 typeck_results: ty::TypeckResults<'tcx>,
104 body: &'tcx hir::Body<'tcx>,
106 rustc_dump_user_substs: bool,
109 impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> {
111 fcx: &'cx FnCtxt<'cx, 'tcx>,
112 body: &'tcx hir::Body<'tcx>,
113 rustc_dump_user_substs: bool,
114 ) -> WritebackCx<'cx, 'tcx> {
115 let owner = body.id().hir_id.owner;
119 typeck_results: ty::TypeckResults::new(owner),
121 rustc_dump_user_substs,
125 fn tcx(&self) -> TyCtxt<'tcx> {
129 fn write_ty_to_typeck_results(&mut self, hir_id: hir::HirId, ty: Ty<'tcx>) {
130 debug!("write_ty_to_typeck_results({:?}, {:?})", hir_id, ty);
131 assert!(!ty.needs_infer() && !ty.has_placeholders() && !ty.has_free_regions());
132 self.typeck_results.node_types_mut().insert(hir_id, ty);
135 // Hacky hack: During type-checking, we treat *all* operators
136 // as potentially overloaded. But then, during writeback, if
137 // we observe that something like `a+b` is (known to be)
138 // operating on scalars, we clear the overload.
139 fn fix_scalar_builtin_expr(&mut self, e: &hir::Expr<'_>) {
141 hir::ExprKind::Unary(hir::UnOp::Neg | hir::UnOp::Not, ref inner) => {
142 let inner_ty = self.fcx.node_ty(inner.hir_id);
143 let inner_ty = self.fcx.resolve_vars_if_possible(inner_ty);
145 if inner_ty.is_scalar() {
146 let mut typeck_results = self.fcx.typeck_results.borrow_mut();
147 typeck_results.type_dependent_defs_mut().remove(e.hir_id);
148 typeck_results.node_substs_mut().remove(e.hir_id);
151 hir::ExprKind::Binary(ref op, ref lhs, ref rhs)
152 | hir::ExprKind::AssignOp(ref op, ref lhs, ref rhs) => {
153 let lhs_ty = self.fcx.node_ty(lhs.hir_id);
154 let lhs_ty = self.fcx.resolve_vars_if_possible(lhs_ty);
156 let rhs_ty = self.fcx.node_ty(rhs.hir_id);
157 let rhs_ty = self.fcx.resolve_vars_if_possible(rhs_ty);
159 if lhs_ty.is_scalar() && rhs_ty.is_scalar() {
160 let mut typeck_results = self.fcx.typeck_results.borrow_mut();
161 typeck_results.type_dependent_defs_mut().remove(e.hir_id);
162 typeck_results.node_substs_mut().remove(e.hir_id);
165 hir::ExprKind::Binary(..) => {
166 if !op.node.is_by_value() {
167 let mut adjustments = typeck_results.adjustments_mut();
168 if let Some(a) = adjustments.get_mut(lhs.hir_id) {
171 if let Some(a) = adjustments.get_mut(rhs.hir_id) {
176 hir::ExprKind::AssignOp(..) => {
177 if let Some(a) = typeck_results.adjustments_mut().get_mut(lhs.hir_id) {
189 // Similar to operators, indexing is always assumed to be overloaded
190 // Here, correct cases where an indexing expression can be simplified
191 // to use builtin indexing because the index type is known to be
193 fn fix_index_builtin_expr(&mut self, e: &hir::Expr<'_>) {
194 if let hir::ExprKind::Index(ref base, ref index) = e.kind {
195 let mut typeck_results = self.fcx.typeck_results.borrow_mut();
197 // All valid indexing looks like this; might encounter non-valid indexes at this point.
198 let base_ty = typeck_results
199 .expr_ty_adjusted_opt(&base)
200 .map(|t| self.fcx.resolve_vars_if_possible(t).kind());
201 if base_ty.is_none() {
202 // When encountering `return [0][0]` outside of a `fn` body we can encounter a base
203 // that isn't in the type table. We assume more relevant errors have already been
204 // emitted, so we delay an ICE if none have. (#64638)
205 self.tcx().sess.delay_span_bug(e.span, &format!("bad base: `{:?}`", base));
207 if let Some(ty::Ref(_, base_ty, _)) = base_ty {
208 let index_ty = typeck_results.expr_ty_adjusted_opt(&index).unwrap_or_else(|| {
209 // When encountering `return [0][0]` outside of a `fn` body we would attempt
210 // to access an unexistend index. We assume that more relevant errors will
211 // already have been emitted, so we only gate on this with an ICE if no
212 // error has been emitted. (#64638)
213 self.fcx.tcx.ty_error_with_message(
215 &format!("bad index {:?} for base: `{:?}`", index, base),
218 let index_ty = self.fcx.resolve_vars_if_possible(index_ty);
220 if base_ty.builtin_index().is_some() && index_ty == self.fcx.tcx.types.usize {
221 // Remove the method call record
222 typeck_results.type_dependent_defs_mut().remove(e.hir_id);
223 typeck_results.node_substs_mut().remove(e.hir_id);
225 if let Some(a) = typeck_results.adjustments_mut().get_mut(base.hir_id) {
226 // Discard the need for a mutable borrow
228 // Extra adjustment made when indexing causes a drop
229 // of size information - we need to get rid of it
230 // Since this is "after" the other adjustment to be
231 // discarded, we do an extra `pop()`
232 if let Some(Adjustment {
233 kind: Adjust::Pointer(PointerCast::Unsize), ..
236 // So the borrow discard actually happens here
246 ///////////////////////////////////////////////////////////////////////////
247 // Impl of Visitor for Resolver
249 // This is the master code which walks the AST. It delegates most of
250 // the heavy lifting to the generic visit and resolve functions
251 // below. In general, a function is made into a `visitor` if it must
252 // traffic in node-ids or update typeck results in the type context etc.
254 impl<'cx, 'tcx> Visitor<'tcx> for WritebackCx<'cx, 'tcx> {
255 type Map = intravisit::ErasedMap<'tcx>;
257 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
258 NestedVisitorMap::None
261 fn visit_expr(&mut self, e: &'tcx hir::Expr<'tcx>) {
262 self.fix_scalar_builtin_expr(e);
263 self.fix_index_builtin_expr(e);
265 self.visit_node_id(e.span, e.hir_id);
268 hir::ExprKind::Closure(_, _, body, _, _) => {
269 let body = self.fcx.tcx.hir().body(body);
270 for param in body.params {
271 self.visit_node_id(e.span, param.hir_id);
274 self.visit_body(body);
276 hir::ExprKind::Struct(_, fields, _) => {
277 for field in fields {
278 self.visit_field_id(field.hir_id);
281 hir::ExprKind::Field(..) => {
282 self.visit_field_id(e.hir_id);
287 intravisit::walk_expr(self, e);
290 fn visit_block(&mut self, b: &'tcx hir::Block<'tcx>) {
291 self.visit_node_id(b.span, b.hir_id);
292 intravisit::walk_block(self, b);
295 fn visit_pat(&mut self, p: &'tcx hir::Pat<'tcx>) {
297 hir::PatKind::Binding(..) => {
298 let typeck_results = self.fcx.typeck_results.borrow();
300 typeck_results.extract_binding_mode(self.tcx().sess, p.hir_id, p.span)
302 self.typeck_results.pat_binding_modes_mut().insert(p.hir_id, bm);
305 hir::PatKind::Struct(_, fields, _) => {
306 for field in fields {
307 self.visit_field_id(field.hir_id);
313 self.visit_pat_adjustments(p.span, p.hir_id);
315 self.visit_node_id(p.span, p.hir_id);
316 intravisit::walk_pat(self, p);
319 fn visit_local(&mut self, l: &'tcx hir::Local<'tcx>) {
320 intravisit::walk_local(self, l);
321 let var_ty = self.fcx.local_ty(l.span, l.hir_id).decl_ty;
322 let var_ty = self.resolve(var_ty, &l.span);
323 self.write_ty_to_typeck_results(l.hir_id, var_ty);
326 fn visit_ty(&mut self, hir_ty: &'tcx hir::Ty<'tcx>) {
327 intravisit::walk_ty(self, hir_ty);
328 let ty = self.fcx.node_ty(hir_ty.hir_id);
329 let ty = self.resolve(ty, &hir_ty.span);
330 self.write_ty_to_typeck_results(hir_ty.hir_id, ty);
334 impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> {
335 fn visit_min_capture_map(&mut self) {
336 let mut min_captures_wb = ty::MinCaptureInformationMap::with_capacity_and_hasher(
337 self.fcx.typeck_results.borrow().closure_min_captures.len(),
340 for (closure_def_id, root_min_captures) in
341 self.fcx.typeck_results.borrow().closure_min_captures.iter()
343 let mut root_var_map_wb = ty::RootVariableMinCaptureList::with_capacity_and_hasher(
344 root_min_captures.len(),
347 for (var_hir_id, min_list) in root_min_captures.iter() {
348 let min_list_wb = min_list
350 .map(|captured_place| {
351 let locatable = captured_place.info.path_expr_id.unwrap_or(
352 self.tcx().hir().local_def_id_to_hir_id(closure_def_id.expect_local()),
355 self.resolve(captured_place.clone(), &locatable)
358 root_var_map_wb.insert(*var_hir_id, min_list_wb);
360 min_captures_wb.insert(*closure_def_id, root_var_map_wb);
363 self.typeck_results.closure_min_captures = min_captures_wb;
366 fn visit_upvar_capture_map(&mut self) {
367 for (upvar_id, upvar_capture) in self.fcx.typeck_results.borrow().upvar_capture_map.iter() {
368 let new_upvar_capture = match *upvar_capture {
369 ty::UpvarCapture::ByValue(span) => ty::UpvarCapture::ByValue(span),
370 ty::UpvarCapture::ByRef(ref upvar_borrow) => {
371 ty::UpvarCapture::ByRef(ty::UpvarBorrow {
372 kind: upvar_borrow.kind,
373 region: self.tcx().lifetimes.re_erased,
377 debug!("Upvar capture for {:?} resolved to {:?}", upvar_id, new_upvar_capture);
378 self.typeck_results.upvar_capture_map.insert(*upvar_id, new_upvar_capture);
382 fn visit_closures(&mut self) {
383 let fcx_typeck_results = self.fcx.typeck_results.borrow();
384 assert_eq!(fcx_typeck_results.hir_owner, self.typeck_results.hir_owner);
385 let common_hir_owner = fcx_typeck_results.hir_owner;
387 for (id, origin) in fcx_typeck_results.closure_kind_origins().iter() {
388 let hir_id = hir::HirId { owner: common_hir_owner, local_id: *id };
389 let place_span = origin.0;
390 let place = self.resolve(origin.1.clone(), &place_span);
391 self.typeck_results.closure_kind_origins_mut().insert(hir_id, (place_span, place));
395 fn visit_coercion_casts(&mut self) {
396 let fcx_typeck_results = self.fcx.typeck_results.borrow();
397 let fcx_coercion_casts = fcx_typeck_results.coercion_casts();
398 assert_eq!(fcx_typeck_results.hir_owner, self.typeck_results.hir_owner);
400 for local_id in fcx_coercion_casts {
401 self.typeck_results.set_coercion_cast(*local_id);
405 fn visit_user_provided_tys(&mut self) {
406 let fcx_typeck_results = self.fcx.typeck_results.borrow();
407 assert_eq!(fcx_typeck_results.hir_owner, self.typeck_results.hir_owner);
408 let common_hir_owner = fcx_typeck_results.hir_owner;
410 let mut errors_buffer = Vec::new();
411 for (&local_id, c_ty) in fcx_typeck_results.user_provided_types().iter() {
412 let hir_id = hir::HirId { owner: common_hir_owner, local_id };
414 if cfg!(debug_assertions) && c_ty.needs_infer() {
416 hir_id.to_span(self.fcx.tcx),
417 "writeback: `{:?}` has inference variables",
422 self.typeck_results.user_provided_types_mut().insert(hir_id, *c_ty);
424 if let ty::UserType::TypeOf(_, user_substs) = c_ty.value {
425 if self.rustc_dump_user_substs {
426 // This is a unit-testing mechanism.
427 let span = self.tcx().hir().span(hir_id);
428 // We need to buffer the errors in order to guarantee a consistent
429 // order when emitting them.
433 .struct_span_err(span, &format!("user substs: {:?}", user_substs));
434 err.buffer(&mut errors_buffer);
439 if !errors_buffer.is_empty() {
440 errors_buffer.sort_by_key(|diag| diag.span.primary_span());
441 for diag in errors_buffer.drain(..) {
442 self.tcx().sess.diagnostic().emit_diagnostic(&diag);
447 fn visit_user_provided_sigs(&mut self) {
448 let fcx_typeck_results = self.fcx.typeck_results.borrow();
449 assert_eq!(fcx_typeck_results.hir_owner, self.typeck_results.hir_owner);
451 for (&def_id, c_sig) in fcx_typeck_results.user_provided_sigs.iter() {
452 if cfg!(debug_assertions) && c_sig.needs_infer() {
454 self.fcx.tcx.hir().span_if_local(def_id).unwrap(),
455 "writeback: `{:?}` has inference variables",
460 self.typeck_results.user_provided_sigs.insert(def_id, *c_sig);
464 fn visit_generator_interior_types(&mut self) {
465 let fcx_typeck_results = self.fcx.typeck_results.borrow();
466 assert_eq!(fcx_typeck_results.hir_owner, self.typeck_results.hir_owner);
467 self.typeck_results.generator_interior_types =
468 fcx_typeck_results.generator_interior_types.clone();
471 fn visit_opaque_types(&mut self, span: Span) {
472 for (&def_id, opaque_defn) in self.fcx.opaque_types.borrow().iter() {
473 let hir_id = self.tcx().hir().local_def_id_to_hir_id(def_id.expect_local());
474 let instantiated_ty = self.resolve(opaque_defn.concrete_ty, &hir_id);
476 debug_assert!(!instantiated_ty.has_escaping_bound_vars());
479 // * `fn foo<T>() -> Foo<T>`
480 // * `fn foo<T: Bound + Other>() -> Foo<T>`
481 // from being defining.
483 // Also replace all generic params with the ones from the opaque type
484 // definition so that
486 // type Foo<T> = impl Baz + 'static;
487 // fn foo<U>() -> Foo<U> { .. }
489 // figures out the concrete type with `U`, but the stored type is with `T`.
490 let definition_ty = self.fcx.infer_opaque_definition_from_instantiation(
497 let mut skip_add = false;
499 if let ty::Opaque(defin_ty_def_id, _substs) = *definition_ty.kind() {
500 if let hir::OpaqueTyOrigin::Misc = opaque_defn.origin {
501 if def_id == defin_ty_def_id {
503 "skipping adding concrete definition for opaque type {:?} {:?}",
504 opaque_defn, defin_ty_def_id
511 if !opaque_defn.substs.needs_infer() {
512 // We only want to add an entry into `concrete_opaque_types`
513 // if we actually found a defining usage of this opaque type.
514 // Otherwise, we do nothing - we'll either find a defining usage
515 // in some other location, or we'll end up emitting an error due
516 // to the lack of defining usage
518 let new = ty::ResolvedOpaqueTy {
519 concrete_type: definition_ty,
520 substs: opaque_defn.substs,
523 let old = self.typeck_results.concrete_opaque_types.insert(def_id, new);
524 if let Some(old) = old {
525 if old.concrete_type != definition_ty || old.substs != opaque_defn.substs {
528 "`visit_opaque_types` tried to write different types for the same \
529 opaque type: {:?}, {:?}, {:?}, {:?}",
539 self.tcx().sess.delay_span_bug(span, "`opaque_defn` has inference variables");
544 fn visit_field_id(&mut self, hir_id: hir::HirId) {
545 if let Some(index) = self.fcx.typeck_results.borrow_mut().field_indices_mut().remove(hir_id)
547 self.typeck_results.field_indices_mut().insert(hir_id, index);
551 fn visit_node_id(&mut self, span: Span, hir_id: hir::HirId) {
552 // Export associated path extensions and method resolutions.
554 self.fcx.typeck_results.borrow_mut().type_dependent_defs_mut().remove(hir_id)
556 self.typeck_results.type_dependent_defs_mut().insert(hir_id, def);
559 // Resolve any borrowings for the node with id `node_id`
560 self.visit_adjustments(span, hir_id);
562 // Resolve the type of the node with id `node_id`
563 let n_ty = self.fcx.node_ty(hir_id);
564 let n_ty = self.resolve(n_ty, &span);
565 self.write_ty_to_typeck_results(hir_id, n_ty);
566 debug!("node {:?} has type {:?}", hir_id, n_ty);
568 // Resolve any substitutions
569 if let Some(substs) = self.fcx.typeck_results.borrow().node_substs_opt(hir_id) {
570 let substs = self.resolve(substs, &span);
571 debug!("write_substs_to_tcx({:?}, {:?})", hir_id, substs);
572 assert!(!substs.needs_infer() && !substs.has_placeholders());
573 self.typeck_results.node_substs_mut().insert(hir_id, substs);
577 fn visit_adjustments(&mut self, span: Span, hir_id: hir::HirId) {
578 let adjustment = self.fcx.typeck_results.borrow_mut().adjustments_mut().remove(hir_id);
581 debug!("no adjustments for node {:?}", hir_id);
584 Some(adjustment) => {
585 let resolved_adjustment = self.resolve(adjustment, &span);
586 debug!("adjustments for node {:?}: {:?}", hir_id, resolved_adjustment);
587 self.typeck_results.adjustments_mut().insert(hir_id, resolved_adjustment);
592 fn visit_pat_adjustments(&mut self, span: Span, hir_id: hir::HirId) {
593 let adjustment = self.fcx.typeck_results.borrow_mut().pat_adjustments_mut().remove(hir_id);
596 debug!("no pat_adjustments for node {:?}", hir_id);
599 Some(adjustment) => {
600 let resolved_adjustment = self.resolve(adjustment, &span);
601 debug!("pat_adjustments for node {:?}: {:?}", hir_id, resolved_adjustment);
602 self.typeck_results.pat_adjustments_mut().insert(hir_id, resolved_adjustment);
607 fn visit_liberated_fn_sigs(&mut self) {
608 let fcx_typeck_results = self.fcx.typeck_results.borrow();
609 assert_eq!(fcx_typeck_results.hir_owner, self.typeck_results.hir_owner);
610 let common_hir_owner = fcx_typeck_results.hir_owner;
612 for (&local_id, &fn_sig) in fcx_typeck_results.liberated_fn_sigs().iter() {
613 let hir_id = hir::HirId { owner: common_hir_owner, local_id };
614 let fn_sig = self.resolve(fn_sig, &hir_id);
615 self.typeck_results.liberated_fn_sigs_mut().insert(hir_id, fn_sig);
619 fn visit_fru_field_types(&mut self) {
620 let fcx_typeck_results = self.fcx.typeck_results.borrow();
621 assert_eq!(fcx_typeck_results.hir_owner, self.typeck_results.hir_owner);
622 let common_hir_owner = fcx_typeck_results.hir_owner;
624 for (&local_id, ftys) in fcx_typeck_results.fru_field_types().iter() {
625 let hir_id = hir::HirId { owner: common_hir_owner, local_id };
626 let ftys = self.resolve(ftys.clone(), &hir_id);
627 self.typeck_results.fru_field_types_mut().insert(hir_id, ftys);
631 fn resolve<T>(&mut self, x: T, span: &dyn Locatable) -> T
633 T: TypeFoldable<'tcx>,
635 let mut resolver = Resolver::new(self.fcx, span, self.body);
636 let x = x.fold_with(&mut resolver);
637 if cfg!(debug_assertions) && x.needs_infer() {
638 span_bug!(span.to_span(self.fcx.tcx), "writeback: `{:?}` has inference variables", x);
641 // We may have introduced e.g. `ty::Error`, if inference failed, make sure
642 // to mark the `TypeckResults` as tainted in that case, so that downstream
643 // users of the typeck results don't produce extra errors, or worse, ICEs.
644 if resolver.replaced_with_error {
645 // FIXME(eddyb) keep track of `ErrorReported` from where the error was emitted.
646 self.typeck_results.tainted_by_errors = Some(ErrorReported);
653 crate trait Locatable {
654 fn to_span(&self, tcx: TyCtxt<'_>) -> Span;
657 impl Locatable for Span {
658 fn to_span(&self, _: TyCtxt<'_>) -> Span {
663 impl Locatable for hir::HirId {
664 fn to_span(&self, tcx: TyCtxt<'_>) -> Span {
665 tcx.hir().span(*self)
669 /// The Resolver. This is the type folding engine that detects
670 /// unresolved types and so forth.
671 crate struct Resolver<'cx, 'tcx> {
673 infcx: &'cx InferCtxt<'cx, 'tcx>,
674 span: &'cx dyn Locatable,
675 body: &'tcx hir::Body<'tcx>,
677 /// Set to `true` if any `Ty` or `ty::Const` had to be replaced with an `Error`.
678 replaced_with_error: bool,
681 impl<'cx, 'tcx> Resolver<'cx, 'tcx> {
683 fcx: &'cx FnCtxt<'cx, 'tcx>,
684 span: &'cx dyn Locatable,
685 body: &'tcx hir::Body<'tcx>,
686 ) -> Resolver<'cx, 'tcx> {
687 Resolver { tcx: fcx.tcx, infcx: fcx, span, body, replaced_with_error: false }
690 fn report_type_error(&self, t: Ty<'tcx>) {
691 if !self.tcx.sess.has_errors() {
693 .emit_inference_failure_err(
694 Some(self.body.id()),
695 self.span.to_span(self.tcx),
704 fn report_const_error(&self, c: &'tcx ty::Const<'tcx>) {
705 if !self.tcx.sess.has_errors() {
707 .emit_inference_failure_err(
708 Some(self.body.id()),
709 self.span.to_span(self.tcx),
719 impl<'cx, 'tcx> TypeFolder<'tcx> for Resolver<'cx, 'tcx> {
720 fn tcx<'a>(&'a self) -> TyCtxt<'tcx> {
724 fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> {
725 match self.infcx.fully_resolve(t) {
726 Ok(t) => self.infcx.tcx.erase_regions(t),
728 debug!("Resolver::fold_ty: input type `{:?}` not fully resolvable", t);
729 self.report_type_error(t);
730 self.replaced_with_error = true;
731 self.tcx().ty_error()
736 fn fold_region(&mut self, r: ty::Region<'tcx>) -> ty::Region<'tcx> {
737 debug_assert!(!r.is_late_bound(), "Should not be resolving bound region.");
738 self.tcx.lifetimes.re_erased
741 fn fold_const(&mut self, ct: &'tcx ty::Const<'tcx>) -> &'tcx ty::Const<'tcx> {
742 match self.infcx.fully_resolve(ct) {
743 Ok(ct) => self.infcx.tcx.erase_regions(ct),
745 debug!("Resolver::fold_const: input const `{:?}` not fully resolvable", ct);
746 self.report_const_error(ct);
747 self.replaced_with_error = true;
748 self.tcx().const_error(ct.ty)
754 ///////////////////////////////////////////////////////////////////////////
755 // During type check, we store promises with the result of trait
756 // lookup rather than the actual results (because the results are not
757 // necessarily available immediately). These routines unwind the
758 // promises. It is expected that we will have already reported any
759 // errors that may be encountered, so if the promises store an error,
760 // a dummy result is returned.