| // Type resolution: the phase that finds all the types in the AST with |
| // unresolved type variables and replaces "ty_var" types with their |
| // substitutions. |
| |
| use crate::check::FnCtxt; |
| |
| use rustc::hir; |
| use rustc::hir::def_id::{DefId, DefIdSet, DefIndex}; |
| use rustc::hir::intravisit::{self, NestedVisitorMap, Visitor}; |
| use rustc::infer::error_reporting::TypeAnnotationNeeded::E0282; |
| use rustc::infer::InferCtxt; |
| use rustc::ty::adjustment::{Adjust, Adjustment, PointerCast}; |
| use rustc::ty::fold::{TypeFoldable, TypeFolder}; |
| use rustc::ty::{self, Ty, TyCtxt}; |
| use rustc_data_structures::sync::Lrc; |
| use rustc_span::symbol::sym; |
| use rustc_span::Span; |
| |
| use std::mem; |
| |
| /////////////////////////////////////////////////////////////////////////// |
| // Entry point |
| |
| // During type inference, partially inferred types are |
| // represented using Type variables (ty::Infer). These don't appear in |
| // the final TypeckTables since all of the types should have been |
| // inferred once typeck_tables_of is done. |
| // When type inference is running however, having to update the typeck |
| // tables every time a new type is inferred would be unreasonably slow, |
| // so instead all of the replacement happens at the end in |
| // resolve_type_vars_in_body, which creates a new TypeTables which |
| // doesn't contain any inference types. |
| impl<'a, 'tcx> FnCtxt<'a, 'tcx> { |
| pub fn resolve_type_vars_in_body( |
| &self, |
| body: &'tcx hir::Body<'tcx>, |
| ) -> &'tcx ty::TypeckTables<'tcx> { |
| let item_id = self.tcx.hir().body_owner(body.id()); |
| let item_def_id = self.tcx.hir().local_def_id(item_id); |
| |
| // This attribute causes us to dump some writeback information |
| // in the form of errors, which is uSymbolfor unit tests. |
| let rustc_dump_user_substs = self.tcx.has_attr(item_def_id, sym::rustc_dump_user_substs); |
| |
| let mut wbcx = WritebackCx::new(self, body, rustc_dump_user_substs); |
| for param in body.params { |
| wbcx.visit_node_id(param.pat.span, param.hir_id); |
| } |
| // Type only exists for constants and statics, not functions. |
| match self.tcx.hir().body_owner_kind(item_id) { |
| hir::BodyOwnerKind::Const | hir::BodyOwnerKind::Static(_) => { |
| wbcx.visit_node_id(body.value.span, item_id); |
| } |
| hir::BodyOwnerKind::Closure | hir::BodyOwnerKind::Fn => (), |
| } |
| wbcx.visit_body(body); |
| wbcx.visit_upvar_capture_map(); |
| wbcx.visit_closures(); |
| wbcx.visit_liberated_fn_sigs(); |
| wbcx.visit_fru_field_types(); |
| wbcx.visit_opaque_types(body.value.span); |
| wbcx.visit_coercion_casts(); |
| wbcx.visit_free_region_map(); |
| wbcx.visit_user_provided_tys(); |
| wbcx.visit_user_provided_sigs(); |
| wbcx.visit_generator_interior_types(); |
| |
| let used_trait_imports = mem::replace( |
| &mut self.tables.borrow_mut().used_trait_imports, |
| Lrc::new(DefIdSet::default()), |
| ); |
| debug!("used_trait_imports({:?}) = {:?}", item_def_id, used_trait_imports); |
| wbcx.tables.used_trait_imports = used_trait_imports; |
| |
| wbcx.tables.upvar_list = |
| mem::replace(&mut self.tables.borrow_mut().upvar_list, Default::default()); |
| |
| wbcx.tables.tainted_by_errors = self.is_tainted_by_errors(); |
| |
| debug!("writeback: tables for {:?} are {:#?}", item_def_id, wbcx.tables); |
| |
| self.tcx.arena.alloc(wbcx.tables) |
| } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////// |
| // The Writeback context. This visitor walks the AST, checking the |
| // fn-specific tables to find references to types or regions. It |
| // resolves those regions to remove inference variables and writes the |
| // final result back into the master tables in the tcx. Here and |
| // there, it applies a few ad-hoc checks that were not convenient to |
| // do elsewhere. |
| |
| struct WritebackCx<'cx, 'tcx> { |
| fcx: &'cx FnCtxt<'cx, 'tcx>, |
| |
| tables: ty::TypeckTables<'tcx>, |
| |
| body: &'tcx hir::Body<'tcx>, |
| |
| rustc_dump_user_substs: bool, |
| } |
| |
| impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> { |
| fn new( |
| fcx: &'cx FnCtxt<'cx, 'tcx>, |
| body: &'tcx hir::Body<'tcx>, |
| rustc_dump_user_substs: bool, |
| ) -> WritebackCx<'cx, 'tcx> { |
| let owner = body.id().hir_id; |
| |
| WritebackCx { |
| fcx, |
| tables: ty::TypeckTables::empty(Some(DefId::local(owner.owner))), |
| body, |
| rustc_dump_user_substs, |
| } |
| } |
| |
| fn tcx(&self) -> TyCtxt<'tcx> { |
| self.fcx.tcx |
| } |
| |
| fn write_ty_to_tables(&mut self, hir_id: hir::HirId, ty: Ty<'tcx>) { |
| debug!("write_ty_to_tables({:?}, {:?})", hir_id, ty); |
| assert!(!ty.needs_infer() && !ty.has_placeholders()); |
| self.tables.node_types_mut().insert(hir_id, ty); |
| } |
| |
| // Hacky hack: During type-checking, we treat *all* operators |
| // as potentially overloaded. But then, during writeback, if |
| // we observe that something like `a+b` is (known to be) |
| // operating on scalars, we clear the overload. |
| fn fix_scalar_builtin_expr(&mut self, e: &hir::Expr<'_>) { |
| match e.kind { |
| hir::ExprKind::Unary(hir::UnNeg, ref inner) |
| | hir::ExprKind::Unary(hir::UnNot, ref inner) => { |
| let inner_ty = self.fcx.node_ty(inner.hir_id); |
| let inner_ty = self.fcx.resolve_vars_if_possible(&inner_ty); |
| |
| if inner_ty.is_scalar() { |
| let mut tables = self.fcx.tables.borrow_mut(); |
| tables.type_dependent_defs_mut().remove(e.hir_id); |
| tables.node_substs_mut().remove(e.hir_id); |
| } |
| } |
| hir::ExprKind::Binary(ref op, ref lhs, ref rhs) |
| | hir::ExprKind::AssignOp(ref op, ref lhs, ref rhs) => { |
| let lhs_ty = self.fcx.node_ty(lhs.hir_id); |
| let lhs_ty = self.fcx.resolve_vars_if_possible(&lhs_ty); |
| |
| let rhs_ty = self.fcx.node_ty(rhs.hir_id); |
| let rhs_ty = self.fcx.resolve_vars_if_possible(&rhs_ty); |
| |
| if lhs_ty.is_scalar() && rhs_ty.is_scalar() { |
| let mut tables = self.fcx.tables.borrow_mut(); |
| tables.type_dependent_defs_mut().remove(e.hir_id); |
| tables.node_substs_mut().remove(e.hir_id); |
| |
| match e.kind { |
| hir::ExprKind::Binary(..) => { |
| if !op.node.is_by_value() { |
| let mut adjustments = tables.adjustments_mut(); |
| adjustments.get_mut(lhs.hir_id).map(|a| a.pop()); |
| adjustments.get_mut(rhs.hir_id).map(|a| a.pop()); |
| } |
| } |
| hir::ExprKind::AssignOp(..) => { |
| tables.adjustments_mut().get_mut(lhs.hir_id).map(|a| a.pop()); |
| } |
| _ => {} |
| } |
| } |
| } |
| _ => {} |
| } |
| } |
| |
| // Similar to operators, indexing is always assumed to be overloaded |
| // Here, correct cases where an indexing expression can be simplified |
| // to use builtin indexing because the index type is known to be |
| // usize-ish |
| fn fix_index_builtin_expr(&mut self, e: &hir::Expr<'_>) { |
| if let hir::ExprKind::Index(ref base, ref index) = e.kind { |
| let mut tables = self.fcx.tables.borrow_mut(); |
| |
| // All valid indexing looks like this; might encounter non-valid indexes at this point. |
| let base_ty = tables.expr_ty_adjusted_opt(&base).map(|t| &t.kind); |
| if base_ty.is_none() { |
| // When encountering `return [0][0]` outside of a `fn` body we can encounter a base |
| // that isn't in the type table. We assume more relevant errors have already been |
| // emitted, so we delay an ICE if none have. (#64638) |
| self.tcx().sess.delay_span_bug(e.span, &format!("bad base: `{:?}`", base)); |
| } |
| if let Some(ty::Ref(_, base_ty, _)) = base_ty { |
| let index_ty = tables.expr_ty_adjusted_opt(&index).unwrap_or_else(|| { |
| // When encountering `return [0][0]` outside of a `fn` body we would attempt |
| // to access an unexistend index. We assume that more relevant errors will |
| // already have been emitted, so we only gate on this with an ICE if no |
| // error has been emitted. (#64638) |
| self.tcx().sess.delay_span_bug( |
| e.span, |
| &format!("bad index {:?} for base: `{:?}`", index, base), |
| ); |
| self.fcx.tcx.types.err |
| }); |
| let index_ty = self.fcx.resolve_vars_if_possible(&index_ty); |
| |
| if base_ty.builtin_index().is_some() && index_ty == self.fcx.tcx.types.usize { |
| // Remove the method call record |
| tables.type_dependent_defs_mut().remove(e.hir_id); |
| tables.node_substs_mut().remove(e.hir_id); |
| |
| tables.adjustments_mut().get_mut(base.hir_id).map(|a| { |
| // Discard the need for a mutable borrow |
| match a.pop() { |
| // Extra adjustment made when indexing causes a drop |
| // of size information - we need to get rid of it |
| // Since this is "after" the other adjustment to be |
| // discarded, we do an extra `pop()` |
| Some(Adjustment { |
| kind: Adjust::Pointer(PointerCast::Unsize), .. |
| }) => { |
| // So the borrow discard actually happens here |
| a.pop(); |
| } |
| _ => {} |
| } |
| }); |
| } |
| } |
| } |
| } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////// |
| // Impl of Visitor for Resolver |
| // |
| // This is the master code which walks the AST. It delegates most of |
| // the heavy lifting to the generic visit and resolve functions |
| // below. In general, a function is made into a `visitor` if it must |
| // traffic in node-ids or update tables in the type context etc. |
| |
| impl<'cx, 'tcx> Visitor<'tcx> for WritebackCx<'cx, 'tcx> { |
| fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> { |
| NestedVisitorMap::None |
| } |
| |
| fn visit_expr(&mut self, e: &'tcx hir::Expr<'tcx>) { |
| self.fix_scalar_builtin_expr(e); |
| self.fix_index_builtin_expr(e); |
| |
| self.visit_node_id(e.span, e.hir_id); |
| |
| match e.kind { |
| hir::ExprKind::Closure(_, _, body, _, _) => { |
| let body = self.fcx.tcx.hir().body(body); |
| for param in body.params { |
| self.visit_node_id(e.span, param.hir_id); |
| } |
| |
| self.visit_body(body); |
| } |
| hir::ExprKind::Struct(_, fields, _) => { |
| for field in fields { |
| self.visit_field_id(field.hir_id); |
| } |
| } |
| hir::ExprKind::Field(..) => { |
| self.visit_field_id(e.hir_id); |
| } |
| _ => {} |
| } |
| |
| intravisit::walk_expr(self, e); |
| } |
| |
| fn visit_block(&mut self, b: &'tcx hir::Block<'tcx>) { |
| self.visit_node_id(b.span, b.hir_id); |
| intravisit::walk_block(self, b); |
| } |
| |
| fn visit_pat(&mut self, p: &'tcx hir::Pat<'tcx>) { |
| match p.kind { |
| hir::PatKind::Binding(..) => { |
| let tables = self.fcx.tables.borrow(); |
| if let Some(bm) = tables.extract_binding_mode(self.tcx().sess, p.hir_id, p.span) { |
| self.tables.pat_binding_modes_mut().insert(p.hir_id, bm); |
| } |
| } |
| hir::PatKind::Struct(_, fields, _) => { |
| for field in fields { |
| self.visit_field_id(field.hir_id); |
| } |
| } |
| _ => {} |
| }; |
| |
| self.visit_pat_adjustments(p.span, p.hir_id); |
| |
| self.visit_node_id(p.span, p.hir_id); |
| intravisit::walk_pat(self, p); |
| } |
| |
| fn visit_local(&mut self, l: &'tcx hir::Local<'tcx>) { |
| intravisit::walk_local(self, l); |
| let var_ty = self.fcx.local_ty(l.span, l.hir_id).decl_ty; |
| let var_ty = self.resolve(&var_ty, &l.span); |
| self.write_ty_to_tables(l.hir_id, var_ty); |
| } |
| |
| fn visit_ty(&mut self, hir_ty: &'tcx hir::Ty<'tcx>) { |
| intravisit::walk_ty(self, hir_ty); |
| let ty = self.fcx.node_ty(hir_ty.hir_id); |
| let ty = self.resolve(&ty, &hir_ty.span); |
| self.write_ty_to_tables(hir_ty.hir_id, ty); |
| } |
| } |
| |
| impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> { |
| fn visit_upvar_capture_map(&mut self) { |
| for (upvar_id, upvar_capture) in self.fcx.tables.borrow().upvar_capture_map.iter() { |
| let new_upvar_capture = match *upvar_capture { |
| ty::UpvarCapture::ByValue => ty::UpvarCapture::ByValue, |
| ty::UpvarCapture::ByRef(ref upvar_borrow) => { |
| let r = upvar_borrow.region; |
| let r = self.resolve(&r, &upvar_id.var_path.hir_id); |
| ty::UpvarCapture::ByRef(ty::UpvarBorrow { kind: upvar_borrow.kind, region: r }) |
| } |
| }; |
| debug!("Upvar capture for {:?} resolved to {:?}", upvar_id, new_upvar_capture); |
| self.tables.upvar_capture_map.insert(*upvar_id, new_upvar_capture); |
| } |
| } |
| |
| fn visit_closures(&mut self) { |
| let fcx_tables = self.fcx.tables.borrow(); |
| debug_assert_eq!(fcx_tables.local_id_root, self.tables.local_id_root); |
| let common_local_id_root = fcx_tables.local_id_root.unwrap(); |
| |
| for (&id, &origin) in fcx_tables.closure_kind_origins().iter() { |
| let hir_id = hir::HirId { owner: common_local_id_root.index, local_id: id }; |
| self.tables.closure_kind_origins_mut().insert(hir_id, origin); |
| } |
| } |
| |
| fn visit_coercion_casts(&mut self) { |
| let fcx_tables = self.fcx.tables.borrow(); |
| let fcx_coercion_casts = fcx_tables.coercion_casts(); |
| debug_assert_eq!(fcx_tables.local_id_root, self.tables.local_id_root); |
| |
| for local_id in fcx_coercion_casts { |
| self.tables.set_coercion_cast(*local_id); |
| } |
| } |
| |
| fn visit_free_region_map(&mut self) { |
| self.tables.free_region_map = self.fcx.tables.borrow().free_region_map.clone(); |
| debug_assert!(!self.tables.free_region_map.elements().any(|r| r.has_local_value())); |
| } |
| |
| fn visit_user_provided_tys(&mut self) { |
| let fcx_tables = self.fcx.tables.borrow(); |
| debug_assert_eq!(fcx_tables.local_id_root, self.tables.local_id_root); |
| let common_local_id_root = fcx_tables.local_id_root.unwrap(); |
| |
| let mut errors_buffer = Vec::new(); |
| for (&local_id, c_ty) in fcx_tables.user_provided_types().iter() { |
| let hir_id = hir::HirId { owner: common_local_id_root.index, local_id }; |
| |
| if cfg!(debug_assertions) && c_ty.has_local_value() { |
| span_bug!(hir_id.to_span(self.fcx.tcx), "writeback: `{:?}` is a local value", c_ty); |
| }; |
| |
| self.tables.user_provided_types_mut().insert(hir_id, c_ty.clone()); |
| |
| if let ty::UserType::TypeOf(_, user_substs) = c_ty.value { |
| if self.rustc_dump_user_substs { |
| // This is a unit-testing mechanism. |
| let span = self.tcx().hir().span(hir_id); |
| // We need to buffer the errors in order to guarantee a consistent |
| // order when emitting them. |
| let err = self |
| .tcx() |
| .sess |
| .struct_span_err(span, &format!("user substs: {:?}", user_substs)); |
| err.buffer(&mut errors_buffer); |
| } |
| } |
| } |
| |
| if !errors_buffer.is_empty() { |
| errors_buffer.sort_by_key(|diag| diag.span.primary_span()); |
| for diag in errors_buffer.drain(..) { |
| self.tcx().sess.diagnostic().emit_diagnostic(&diag); |
| } |
| } |
| } |
| |
| fn visit_user_provided_sigs(&mut self) { |
| let fcx_tables = self.fcx.tables.borrow(); |
| debug_assert_eq!(fcx_tables.local_id_root, self.tables.local_id_root); |
| |
| for (&def_id, c_sig) in fcx_tables.user_provided_sigs.iter() { |
| if cfg!(debug_assertions) && c_sig.has_local_value() { |
| span_bug!( |
| self.fcx.tcx.hir().span_if_local(def_id).unwrap(), |
| "writeback: `{:?}` is a local value", |
| c_sig |
| ); |
| }; |
| |
| self.tables.user_provided_sigs.insert(def_id, c_sig.clone()); |
| } |
| } |
| |
| fn visit_generator_interior_types(&mut self) { |
| let fcx_tables = self.fcx.tables.borrow(); |
| debug_assert_eq!(fcx_tables.local_id_root, self.tables.local_id_root); |
| self.tables.generator_interior_types = fcx_tables.generator_interior_types.clone(); |
| } |
| |
| fn visit_opaque_types(&mut self, span: Span) { |
| for (&def_id, opaque_defn) in self.fcx.opaque_types.borrow().iter() { |
| let hir_id = self.tcx().hir().as_local_hir_id(def_id).unwrap(); |
| let instantiated_ty = self.resolve(&opaque_defn.concrete_ty, &hir_id); |
| |
| debug_assert!(!instantiated_ty.has_escaping_bound_vars()); |
| |
| // Prevent: |
| // * `fn foo<T>() -> Foo<T>` |
| // * `fn foo<T: Bound + Other>() -> Foo<T>` |
| // from being defining. |
| |
| // Also replace all generic params with the ones from the opaque type |
| // definition so that |
| // ```rust |
| // type Foo<T> = impl Baz + 'static; |
| // fn foo<U>() -> Foo<U> { .. } |
| // ``` |
| // figures out the concrete type with `U`, but the stored type is with `T`. |
| let definition_ty = self.fcx.infer_opaque_definition_from_instantiation( |
| def_id, |
| opaque_defn, |
| instantiated_ty, |
| span, |
| ); |
| |
| let mut skip_add = false; |
| |
| if let ty::Opaque(defin_ty_def_id, _substs) = definition_ty.kind { |
| if let hir::OpaqueTyOrigin::TypeAlias = opaque_defn.origin { |
| if def_id == defin_ty_def_id { |
| debug!( |
| "skipping adding concrete definition for opaque type {:?} {:?}", |
| opaque_defn, defin_ty_def_id |
| ); |
| skip_add = true; |
| } |
| } |
| } |
| |
| if !opaque_defn.substs.has_local_value() { |
| // We only want to add an entry into `concrete_opaque_types` |
| // if we actually found a defining usage of this opaque type. |
| // Otherwise, we do nothing - we'll either find a defining usage |
| // in some other location, or we'll end up emitting an error due |
| // to the lack of defining usage |
| if !skip_add { |
| let new = ty::ResolvedOpaqueTy { |
| concrete_type: definition_ty, |
| substs: opaque_defn.substs, |
| }; |
| |
| let old = self.tables.concrete_opaque_types.insert(def_id, new); |
| if let Some(old) = old { |
| if old.concrete_type != definition_ty || old.substs != opaque_defn.substs { |
| span_bug!( |
| span, |
| "`visit_opaque_types` tried to write different types for the same \ |
| opaque type: {:?}, {:?}, {:?}, {:?}", |
| def_id, |
| definition_ty, |
| opaque_defn, |
| old, |
| ); |
| } |
| } |
| } |
| } else { |
| self.tcx().sess.delay_span_bug(span, "`opaque_defn` is a local value"); |
| } |
| } |
| } |
| |
| fn visit_field_id(&mut self, hir_id: hir::HirId) { |
| if let Some(index) = self.fcx.tables.borrow_mut().field_indices_mut().remove(hir_id) { |
| self.tables.field_indices_mut().insert(hir_id, index); |
| } |
| } |
| |
| fn visit_node_id(&mut self, span: Span, hir_id: hir::HirId) { |
| // Export associated path extensions and method resolutions. |
| if let Some(def) = self.fcx.tables.borrow_mut().type_dependent_defs_mut().remove(hir_id) { |
| self.tables.type_dependent_defs_mut().insert(hir_id, def); |
| } |
| |
| // Resolve any borrowings for the node with id `node_id` |
| self.visit_adjustments(span, hir_id); |
| |
| // Resolve the type of the node with id `node_id` |
| let n_ty = self.fcx.node_ty(hir_id); |
| let n_ty = self.resolve(&n_ty, &span); |
| self.write_ty_to_tables(hir_id, n_ty); |
| debug!("node {:?} has type {:?}", hir_id, n_ty); |
| |
| // Resolve any substitutions |
| if let Some(substs) = self.fcx.tables.borrow().node_substs_opt(hir_id) { |
| let substs = self.resolve(&substs, &span); |
| debug!("write_substs_to_tcx({:?}, {:?})", hir_id, substs); |
| assert!(!substs.needs_infer() && !substs.has_placeholders()); |
| self.tables.node_substs_mut().insert(hir_id, substs); |
| } |
| } |
| |
| fn visit_adjustments(&mut self, span: Span, hir_id: hir::HirId) { |
| let adjustment = self.fcx.tables.borrow_mut().adjustments_mut().remove(hir_id); |
| match adjustment { |
| None => { |
| debug!("no adjustments for node {:?}", hir_id); |
| } |
| |
| Some(adjustment) => { |
| let resolved_adjustment = self.resolve(&adjustment, &span); |
| debug!("adjustments for node {:?}: {:?}", hir_id, resolved_adjustment); |
| self.tables.adjustments_mut().insert(hir_id, resolved_adjustment); |
| } |
| } |
| } |
| |
| fn visit_pat_adjustments(&mut self, span: Span, hir_id: hir::HirId) { |
| let adjustment = self.fcx.tables.borrow_mut().pat_adjustments_mut().remove(hir_id); |
| match adjustment { |
| None => { |
| debug!("no pat_adjustments for node {:?}", hir_id); |
| } |
| |
| Some(adjustment) => { |
| let resolved_adjustment = self.resolve(&adjustment, &span); |
| debug!("pat_adjustments for node {:?}: {:?}", hir_id, resolved_adjustment); |
| self.tables.pat_adjustments_mut().insert(hir_id, resolved_adjustment); |
| } |
| } |
| } |
| |
| fn visit_liberated_fn_sigs(&mut self) { |
| let fcx_tables = self.fcx.tables.borrow(); |
| debug_assert_eq!(fcx_tables.local_id_root, self.tables.local_id_root); |
| let common_local_id_root = fcx_tables.local_id_root.unwrap(); |
| |
| for (&local_id, fn_sig) in fcx_tables.liberated_fn_sigs().iter() { |
| let hir_id = hir::HirId { owner: common_local_id_root.index, local_id }; |
| let fn_sig = self.resolve(fn_sig, &hir_id); |
| self.tables.liberated_fn_sigs_mut().insert(hir_id, fn_sig.clone()); |
| } |
| } |
| |
| fn visit_fru_field_types(&mut self) { |
| let fcx_tables = self.fcx.tables.borrow(); |
| debug_assert_eq!(fcx_tables.local_id_root, self.tables.local_id_root); |
| let common_local_id_root = fcx_tables.local_id_root.unwrap(); |
| |
| for (&local_id, ftys) in fcx_tables.fru_field_types().iter() { |
| let hir_id = hir::HirId { owner: common_local_id_root.index, local_id }; |
| let ftys = self.resolve(ftys, &hir_id); |
| self.tables.fru_field_types_mut().insert(hir_id, ftys); |
| } |
| } |
| |
| fn resolve<T>(&self, x: &T, span: &dyn Locatable) -> T |
| where |
| T: TypeFoldable<'tcx>, |
| { |
| let x = x.fold_with(&mut Resolver::new(self.fcx, span, self.body)); |
| if cfg!(debug_assertions) && x.has_local_value() { |
| span_bug!(span.to_span(self.fcx.tcx), "writeback: `{:?}` is a local value", x); |
| } |
| x |
| } |
| } |
| |
| trait Locatable { |
| fn to_span(&self, tcx: TyCtxt<'_>) -> Span; |
| } |
| |
| impl Locatable for Span { |
| fn to_span(&self, _: TyCtxt<'_>) -> Span { |
| *self |
| } |
| } |
| |
| impl Locatable for DefIndex { |
| fn to_span(&self, tcx: TyCtxt<'_>) -> Span { |
| let hir_id = tcx.hir().def_index_to_hir_id(*self); |
| tcx.hir().span(hir_id) |
| } |
| } |
| |
| impl Locatable for hir::HirId { |
| fn to_span(&self, tcx: TyCtxt<'_>) -> Span { |
| tcx.hir().span(*self) |
| } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////// |
| // The Resolver. This is the type folding engine that detects |
| // unresolved types and so forth. |
| |
| struct Resolver<'cx, 'tcx> { |
| tcx: TyCtxt<'tcx>, |
| infcx: &'cx InferCtxt<'cx, 'tcx>, |
| span: &'cx dyn Locatable, |
| body: &'tcx hir::Body<'tcx>, |
| } |
| |
| impl<'cx, 'tcx> Resolver<'cx, 'tcx> { |
| fn new( |
| fcx: &'cx FnCtxt<'cx, 'tcx>, |
| span: &'cx dyn Locatable, |
| body: &'tcx hir::Body<'tcx>, |
| ) -> Resolver<'cx, 'tcx> { |
| Resolver { tcx: fcx.tcx, infcx: fcx, span, body } |
| } |
| |
| fn report_error(&self, t: Ty<'tcx>) { |
| if !self.tcx.sess.has_errors() { |
| self.infcx |
| .need_type_info_err(Some(self.body.id()), self.span.to_span(self.tcx), t, E0282) |
| .emit(); |
| } |
| } |
| } |
| |
| impl<'cx, 'tcx> TypeFolder<'tcx> for Resolver<'cx, 'tcx> { |
| fn tcx<'a>(&'a self) -> TyCtxt<'tcx> { |
| self.tcx |
| } |
| |
| fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> { |
| match self.infcx.fully_resolve(&t) { |
| Ok(t) => t, |
| Err(_) => { |
| debug!("Resolver::fold_ty: input type `{:?}` not fully resolvable", t); |
| self.report_error(t); |
| self.tcx().types.err |
| } |
| } |
| } |
| |
| // FIXME This should be carefully checked |
| // We could use `self.report_error` but it doesn't accept a ty::Region, right now. |
| fn fold_region(&mut self, r: ty::Region<'tcx>) -> ty::Region<'tcx> { |
| self.infcx.fully_resolve(&r).unwrap_or(self.tcx.lifetimes.re_static) |
| } |
| |
| fn fold_const(&mut self, ct: &'tcx ty::Const<'tcx>) -> &'tcx ty::Const<'tcx> { |
| match self.infcx.fully_resolve(&ct) { |
| Ok(ct) => ct, |
| Err(_) => { |
| debug!("Resolver::fold_const: input const `{:?}` not fully resolvable", ct); |
| // FIXME: we'd like to use `self.report_error`, but it doesn't yet |
| // accept a &'tcx ty::Const. |
| self.tcx().consts.err |
| } |
| } |
| } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////// |
| // During type check, we store promises with the result of trait |
| // lookup rather than the actual results (because the results are not |
| // necessarily available immediately). These routines unwind the |
| // promises. It is expected that we will have already reported any |
| // errors that may be encountered, so if the promises store an error, |
| // a dummy result is returned. |