| //! "Collection" is the process of determining the type and other external |
| //! details of each item in Rust. Collection is specifically concerned |
| //! with *inter-procedural* things -- for example, for a function |
| //! definition, collection will figure out the type and signature of the |
| //! function, but it will not visit the *body* of the function in any way, |
| //! nor examine type annotations on local variables (that's the job of |
| //! type *checking*). |
| //! |
| //! Collecting is ultimately defined by a bundle of queries that |
| //! inquire after various facts about the items in the crate (e.g., |
| //! `type_of`, `generics_of`, `predicates_of`, etc). See the `provide` function |
| //! for the full set. |
| //! |
| //! At present, however, we do run collection across all items in the |
| //! crate as a kind of pass. This should eventually be factored away. |
| |
| use crate::astconv::AstConv; |
| use crate::check::intrinsic::intrinsic_operation_unsafety; |
| use crate::errors; |
| use hir::def::DefKind; |
| use rustc_data_structures::captures::Captures; |
| use rustc_data_structures::fx::{FxHashMap, FxHashSet}; |
| use rustc_errors::{Applicability, DiagnosticBuilder, ErrorGuaranteed, StashKey}; |
| use rustc_hir as hir; |
| use rustc_hir::def_id::{DefId, LocalDefId}; |
| use rustc_hir::intravisit::{self, Visitor}; |
| use rustc_hir::{GenericParamKind, Node}; |
| use rustc_infer::infer::{InferCtxt, TyCtxtInferExt}; |
| use rustc_infer::traits::ObligationCause; |
| use rustc_middle::hir::nested_filter; |
| use rustc_middle::query::Providers; |
| use rustc_middle::ty::util::{Discr, IntTypeExt}; |
| use rustc_middle::ty::{self, AdtKind, Const, IsSuggestable, ToPredicate, Ty, TyCtxt}; |
| use rustc_span::symbol::{kw, sym, Ident, Symbol}; |
| use rustc_span::Span; |
| use rustc_target::spec::abi; |
| use rustc_trait_selection::infer::InferCtxtExt; |
| use rustc_trait_selection::traits::error_reporting::suggestions::NextTypeParamName; |
| use rustc_trait_selection::traits::ObligationCtxt; |
| use std::iter; |
| |
| mod generics_of; |
| mod item_bounds; |
| mod predicates_of; |
| mod resolve_bound_vars; |
| mod type_of; |
| |
| /////////////////////////////////////////////////////////////////////////// |
| // Main entry point |
| |
| fn collect_mod_item_types(tcx: TyCtxt<'_>, module_def_id: LocalDefId) { |
| tcx.hir().visit_item_likes_in_module(module_def_id, &mut CollectItemTypesVisitor { tcx }); |
| } |
| |
| pub fn provide(providers: &mut Providers) { |
| resolve_bound_vars::provide(providers); |
| *providers = Providers { |
| type_of: type_of::type_of, |
| item_bounds: item_bounds::item_bounds, |
| explicit_item_bounds: item_bounds::explicit_item_bounds, |
| generics_of: generics_of::generics_of, |
| predicates_of: predicates_of::predicates_of, |
| predicates_defined_on, |
| explicit_predicates_of: predicates_of::explicit_predicates_of, |
| super_predicates_of: predicates_of::super_predicates_of, |
| implied_predicates_of: predicates_of::implied_predicates_of, |
| super_predicates_that_define_assoc_item: |
| predicates_of::super_predicates_that_define_assoc_item, |
| trait_explicit_predicates_and_bounds: predicates_of::trait_explicit_predicates_and_bounds, |
| type_param_predicates: predicates_of::type_param_predicates, |
| trait_def, |
| adt_def, |
| fn_sig, |
| impl_trait_ref, |
| impl_polarity, |
| generator_kind, |
| collect_mod_item_types, |
| is_type_alias_impl_trait, |
| ..*providers |
| }; |
| } |
| |
| /////////////////////////////////////////////////////////////////////////// |
| |
| /// Context specific to some particular item. This is what implements |
| /// [`AstConv`]. |
| /// |
| /// # `ItemCtxt` vs `FnCtxt` |
| /// |
| /// `ItemCtxt` is primarily used to type-check item signatures and lower them |
| /// from HIR to their [`ty::Ty`] representation, which is exposed using [`AstConv`]. |
| /// It's also used for the bodies of items like structs where the body (the fields) |
| /// are just signatures. |
| /// |
| /// This is in contrast to `FnCtxt`, which is used to type-check bodies of |
| /// functions, closures, and `const`s -- anywhere that expressions and statements show up. |
| /// |
| /// An important thing to note is that `ItemCtxt` does no inference -- it has no [`InferCtxt`] -- |
| /// while `FnCtxt` does do inference. |
| /// |
| /// [`InferCtxt`]: rustc_infer::infer::InferCtxt |
| /// |
| /// # Trait predicates |
| /// |
| /// `ItemCtxt` has information about the predicates that are defined |
| /// on the trait. Unfortunately, this predicate information is |
| /// available in various different forms at various points in the |
| /// process. So we can't just store a pointer to e.g., the AST or the |
| /// parsed ty form, we have to be more flexible. To this end, the |
| /// `ItemCtxt` is parameterized by a `DefId` that it uses to satisfy |
| /// `get_type_parameter_bounds` requests, drawing the information from |
| /// the AST (`hir::Generics`), recursively. |
| pub struct ItemCtxt<'tcx> { |
| tcx: TyCtxt<'tcx>, |
| item_def_id: LocalDefId, |
| } |
| |
| /////////////////////////////////////////////////////////////////////////// |
| |
| #[derive(Default)] |
| pub(crate) struct HirPlaceholderCollector(pub(crate) Vec<Span>); |
| |
| impl<'v> Visitor<'v> for HirPlaceholderCollector { |
| fn visit_ty(&mut self, t: &'v hir::Ty<'v>) { |
| if let hir::TyKind::Infer = t.kind { |
| self.0.push(t.span); |
| } |
| intravisit::walk_ty(self, t) |
| } |
| fn visit_generic_arg(&mut self, generic_arg: &'v hir::GenericArg<'v>) { |
| match generic_arg { |
| hir::GenericArg::Infer(inf) => { |
| self.0.push(inf.span); |
| intravisit::walk_inf(self, inf); |
| } |
| hir::GenericArg::Type(t) => self.visit_ty(t), |
| _ => {} |
| } |
| } |
| fn visit_array_length(&mut self, length: &'v hir::ArrayLen) { |
| if let &hir::ArrayLen::Infer(_, span) = length { |
| self.0.push(span); |
| } |
| intravisit::walk_array_len(self, length) |
| } |
| } |
| |
| struct CollectItemTypesVisitor<'tcx> { |
| tcx: TyCtxt<'tcx>, |
| } |
| |
| /// If there are any placeholder types (`_`), emit an error explaining that this is not allowed |
| /// and suggest adding type parameters in the appropriate place, taking into consideration any and |
| /// all already existing generic type parameters to avoid suggesting a name that is already in use. |
| pub(crate) fn placeholder_type_error<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| generics: Option<&hir::Generics<'_>>, |
| placeholder_types: Vec<Span>, |
| suggest: bool, |
| hir_ty: Option<&hir::Ty<'_>>, |
| kind: &'static str, |
| ) { |
| if placeholder_types.is_empty() { |
| return; |
| } |
| |
| placeholder_type_error_diag(tcx, generics, placeholder_types, vec![], suggest, hir_ty, kind) |
| .emit(); |
| } |
| |
| pub(crate) fn placeholder_type_error_diag<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| generics: Option<&hir::Generics<'_>>, |
| placeholder_types: Vec<Span>, |
| additional_spans: Vec<Span>, |
| suggest: bool, |
| hir_ty: Option<&hir::Ty<'_>>, |
| kind: &'static str, |
| ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> { |
| if placeholder_types.is_empty() { |
| return bad_placeholder(tcx, additional_spans, kind); |
| } |
| |
| let params = generics.map(|g| g.params).unwrap_or_default(); |
| let type_name = params.next_type_param_name(None); |
| let mut sugg: Vec<_> = |
| placeholder_types.iter().map(|sp| (*sp, (*type_name).to_string())).collect(); |
| |
| if let Some(generics) = generics { |
| if let Some(arg) = params.iter().find(|arg| { |
| matches!(arg.name, hir::ParamName::Plain(Ident { name: kw::Underscore, .. })) |
| }) { |
| // Account for `_` already present in cases like `struct S<_>(_);` and suggest |
| // `struct S<T>(T);` instead of `struct S<_, T>(T);`. |
| sugg.push((arg.span, (*type_name).to_string())); |
| } else if let Some(span) = generics.span_for_param_suggestion() { |
| // Account for bounds, we want `fn foo<T: E, K>(_: K)` not `fn foo<T, K: E>(_: K)`. |
| sugg.push((span, format!(", {}", type_name))); |
| } else { |
| sugg.push((generics.span, format!("<{}>", type_name))); |
| } |
| } |
| |
| let mut err = |
| bad_placeholder(tcx, placeholder_types.into_iter().chain(additional_spans).collect(), kind); |
| |
| // Suggest, but only if it is not a function in const or static |
| if suggest { |
| let mut is_fn = false; |
| let mut is_const_or_static = false; |
| |
| if let Some(hir_ty) = hir_ty && let hir::TyKind::BareFn(_) = hir_ty.kind { |
| is_fn = true; |
| |
| // Check if parent is const or static |
| let parent_id = tcx.hir().parent_id(hir_ty.hir_id); |
| let parent_node = tcx.hir().get(parent_id); |
| |
| is_const_or_static = matches!( |
| parent_node, |
| Node::Item(&hir::Item { |
| kind: hir::ItemKind::Const(..) | hir::ItemKind::Static(..), |
| .. |
| }) | Node::TraitItem(&hir::TraitItem { |
| kind: hir::TraitItemKind::Const(..), |
| .. |
| }) | Node::ImplItem(&hir::ImplItem { kind: hir::ImplItemKind::Const(..), .. }) |
| ); |
| } |
| |
| // if function is wrapped around a const or static, |
| // then don't show the suggestion |
| if !(is_fn && is_const_or_static) { |
| err.multipart_suggestion( |
| "use type parameters instead", |
| sugg, |
| Applicability::HasPlaceholders, |
| ); |
| } |
| } |
| |
| err |
| } |
| |
| fn reject_placeholder_type_signatures_in_item<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| item: &'tcx hir::Item<'tcx>, |
| ) { |
| let (generics, suggest) = match &item.kind { |
| hir::ItemKind::Union(_, generics) |
| | hir::ItemKind::Enum(_, generics) |
| | hir::ItemKind::TraitAlias(generics, _) |
| | hir::ItemKind::Trait(_, _, generics, ..) |
| | hir::ItemKind::Impl(hir::Impl { generics, .. }) |
| | hir::ItemKind::Struct(_, generics) => (generics, true), |
| hir::ItemKind::OpaqueTy(hir::OpaqueTy { generics, .. }) |
| | hir::ItemKind::TyAlias(_, generics) => (generics, false), |
| // `static`, `fn` and `const` are handled elsewhere to suggest appropriate type. |
| _ => return, |
| }; |
| |
| let mut visitor = HirPlaceholderCollector::default(); |
| visitor.visit_item(item); |
| |
| placeholder_type_error(tcx, Some(generics), visitor.0, suggest, None, item.kind.descr()); |
| } |
| |
| impl<'tcx> Visitor<'tcx> for CollectItemTypesVisitor<'tcx> { |
| type NestedFilter = nested_filter::OnlyBodies; |
| |
| fn nested_visit_map(&mut self) -> Self::Map { |
| self.tcx.hir() |
| } |
| |
| fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) { |
| convert_item(self.tcx, item.item_id()); |
| reject_placeholder_type_signatures_in_item(self.tcx, item); |
| intravisit::walk_item(self, item); |
| } |
| |
| fn visit_generics(&mut self, generics: &'tcx hir::Generics<'tcx>) { |
| for param in generics.params { |
| match param.kind { |
| hir::GenericParamKind::Lifetime { .. } => {} |
| hir::GenericParamKind::Type { default: Some(_), .. } => { |
| self.tcx.ensure().type_of(param.def_id); |
| } |
| hir::GenericParamKind::Type { .. } => {} |
| hir::GenericParamKind::Const { default, .. } => { |
| self.tcx.ensure().type_of(param.def_id); |
| if let Some(default) = default { |
| // need to store default and type of default |
| self.tcx.ensure().type_of(default.def_id); |
| self.tcx.ensure().const_param_default(param.def_id); |
| } |
| } |
| } |
| } |
| intravisit::walk_generics(self, generics); |
| } |
| |
| fn visit_expr(&mut self, expr: &'tcx hir::Expr<'tcx>) { |
| if let hir::ExprKind::Closure(closure) = expr.kind { |
| self.tcx.ensure().generics_of(closure.def_id); |
| self.tcx.ensure().codegen_fn_attrs(closure.def_id); |
| // We do not call `type_of` for closures here as that |
| // depends on typecheck and would therefore hide |
| // any further errors in case one typeck fails. |
| } |
| intravisit::walk_expr(self, expr); |
| } |
| |
| fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem<'tcx>) { |
| convert_trait_item(self.tcx, trait_item.trait_item_id()); |
| intravisit::walk_trait_item(self, trait_item); |
| } |
| |
| fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem<'tcx>) { |
| convert_impl_item(self.tcx, impl_item.impl_item_id()); |
| intravisit::walk_impl_item(self, impl_item); |
| } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////// |
| // Utility types and common code for the above passes. |
| |
| fn bad_placeholder<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| mut spans: Vec<Span>, |
| kind: &'static str, |
| ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> { |
| let kind = if kind.ends_with('s') { format!("{}es", kind) } else { format!("{}s", kind) }; |
| |
| spans.sort(); |
| tcx.sess.create_err(errors::PlaceholderNotAllowedItemSignatures { spans, kind }) |
| } |
| |
| impl<'tcx> ItemCtxt<'tcx> { |
| pub fn new(tcx: TyCtxt<'tcx>, item_def_id: LocalDefId) -> ItemCtxt<'tcx> { |
| ItemCtxt { tcx, item_def_id } |
| } |
| |
| pub fn to_ty(&self, ast_ty: &hir::Ty<'_>) -> Ty<'tcx> { |
| self.astconv().ast_ty_to_ty(ast_ty) |
| } |
| |
| pub fn hir_id(&self) -> hir::HirId { |
| self.tcx.hir().local_def_id_to_hir_id(self.item_def_id) |
| } |
| |
| pub fn node(&self) -> hir::Node<'tcx> { |
| self.tcx.hir().get(self.hir_id()) |
| } |
| } |
| |
| impl<'tcx> AstConv<'tcx> for ItemCtxt<'tcx> { |
| fn tcx(&self) -> TyCtxt<'tcx> { |
| self.tcx |
| } |
| |
| fn item_def_id(&self) -> DefId { |
| self.item_def_id.to_def_id() |
| } |
| |
| fn get_type_parameter_bounds( |
| &self, |
| span: Span, |
| def_id: LocalDefId, |
| assoc_name: Ident, |
| ) -> ty::GenericPredicates<'tcx> { |
| self.tcx.at(span).type_param_predicates((self.item_def_id, def_id, assoc_name)) |
| } |
| |
| fn re_infer(&self, _: Option<&ty::GenericParamDef>, _: Span) -> Option<ty::Region<'tcx>> { |
| None |
| } |
| |
| fn allow_ty_infer(&self) -> bool { |
| false |
| } |
| |
| fn ty_infer(&self, _: Option<&ty::GenericParamDef>, span: Span) -> Ty<'tcx> { |
| self.tcx().ty_error_with_message(span, "bad placeholder type") |
| } |
| |
| fn ct_infer(&self, ty: Ty<'tcx>, _: Option<&ty::GenericParamDef>, span: Span) -> Const<'tcx> { |
| let ty = self.tcx.fold_regions(ty, |r, _| match *r { |
| // This is never reached in practice. If it ever is reached, |
| // `ReErased` should be changed to `ReStatic`, and any other region |
| // left alone. |
| r => bug!("unexpected region: {r:?}"), |
| }); |
| self.tcx().const_error_with_message(ty, span, "bad placeholder constant") |
| } |
| |
| fn projected_ty_from_poly_trait_ref( |
| &self, |
| span: Span, |
| item_def_id: DefId, |
| item_segment: &hir::PathSegment<'_>, |
| poly_trait_ref: ty::PolyTraitRef<'tcx>, |
| ) -> Ty<'tcx> { |
| if let Some(trait_ref) = poly_trait_ref.no_bound_vars() { |
| let item_substs = self.astconv().create_substs_for_associated_item( |
| span, |
| item_def_id, |
| item_segment, |
| trait_ref.substs, |
| ); |
| self.tcx().mk_projection(item_def_id, item_substs) |
| } else { |
| // There are no late-bound regions; we can just ignore the binder. |
| let (mut mpart_sugg, mut inferred_sugg) = (None, None); |
| let mut bound = String::new(); |
| |
| match self.node() { |
| hir::Node::Field(_) | hir::Node::Ctor(_) | hir::Node::Variant(_) => { |
| let item = self |
| .tcx |
| .hir() |
| .expect_item(self.tcx.hir().get_parent_item(self.hir_id()).def_id); |
| match &item.kind { |
| hir::ItemKind::Enum(_, generics) |
| | hir::ItemKind::Struct(_, generics) |
| | hir::ItemKind::Union(_, generics) => { |
| let lt_name = get_new_lifetime_name(self.tcx, poly_trait_ref, generics); |
| let (lt_sp, sugg) = match generics.params { |
| [] => (generics.span, format!("<{}>", lt_name)), |
| [bound, ..] => { |
| (bound.span.shrink_to_lo(), format!("{}, ", lt_name)) |
| } |
| }; |
| mpart_sugg = Some(errors::AssociatedTypeTraitUninferredGenericParamsMultipartSuggestion { |
| fspan: lt_sp, |
| first: sugg, |
| sspan: span.with_hi(item_segment.ident.span.lo()), |
| second: format!( |
| "{}::", |
| // Replace the existing lifetimes with a new named lifetime. |
| self.tcx.replace_late_bound_regions_uncached( |
| poly_trait_ref, |
| |_| { |
| self.tcx.mk_re_early_bound(ty::EarlyBoundRegion { |
| def_id: item_def_id, |
| index: 0, |
| name: Symbol::intern(<_name), |
| }) |
| } |
| ), |
| ), |
| }); |
| } |
| _ => {} |
| } |
| } |
| hir::Node::Item(hir::Item { |
| kind: |
| hir::ItemKind::Struct(..) | hir::ItemKind::Enum(..) | hir::ItemKind::Union(..), |
| .. |
| }) => {} |
| hir::Node::Item(_) |
| | hir::Node::ForeignItem(_) |
| | hir::Node::TraitItem(_) |
| | hir::Node::ImplItem(_) => { |
| inferred_sugg = Some(span.with_hi(item_segment.ident.span.lo())); |
| bound = format!( |
| "{}::", |
| // Erase named lt, we want `<A as B<'_>::C`, not `<A as B<'a>::C`. |
| self.tcx.anonymize_bound_vars(poly_trait_ref).skip_binder(), |
| ); |
| } |
| _ => {} |
| } |
| self.tcx().ty_error(self.tcx().sess.emit_err( |
| errors::AssociatedTypeTraitUninferredGenericParams { |
| span, |
| inferred_sugg, |
| bound, |
| mpart_sugg, |
| }, |
| )) |
| } |
| } |
| |
| fn probe_adt(&self, _span: Span, ty: Ty<'tcx>) -> Option<ty::AdtDef<'tcx>> { |
| // FIXME(#103640): Should we handle the case where `ty` is a projection? |
| ty.ty_adt_def() |
| } |
| |
| fn set_tainted_by_errors(&self, _: ErrorGuaranteed) { |
| // There's no obvious place to track this, so just let it go. |
| } |
| |
| fn record_ty(&self, _hir_id: hir::HirId, _ty: Ty<'tcx>, _span: Span) { |
| // There's no place to record types from signatures? |
| } |
| |
| fn infcx(&self) -> Option<&InferCtxt<'tcx>> { |
| None |
| } |
| } |
| |
| /// Synthesize a new lifetime name that doesn't clash with any of the lifetimes already present. |
| fn get_new_lifetime_name<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| poly_trait_ref: ty::PolyTraitRef<'tcx>, |
| generics: &hir::Generics<'tcx>, |
| ) -> String { |
| let existing_lifetimes = tcx |
| .collect_referenced_late_bound_regions(&poly_trait_ref) |
| .into_iter() |
| .filter_map(|lt| { |
| if let ty::BoundRegionKind::BrNamed(_, name) = lt { |
| Some(name.as_str().to_string()) |
| } else { |
| None |
| } |
| }) |
| .chain(generics.params.iter().filter_map(|param| { |
| if let hir::GenericParamKind::Lifetime { .. } = ¶m.kind { |
| Some(param.name.ident().as_str().to_string()) |
| } else { |
| None |
| } |
| })) |
| .collect::<FxHashSet<String>>(); |
| |
| let a_to_z_repeat_n = |n| { |
| (b'a'..=b'z').map(move |c| { |
| let mut s = '\''.to_string(); |
| s.extend(std::iter::repeat(char::from(c)).take(n)); |
| s |
| }) |
| }; |
| |
| // If all single char lifetime names are present, we wrap around and double the chars. |
| (1..).flat_map(a_to_z_repeat_n).find(|lt| !existing_lifetimes.contains(lt.as_str())).unwrap() |
| } |
| |
| fn convert_item(tcx: TyCtxt<'_>, item_id: hir::ItemId) { |
| let it = tcx.hir().item(item_id); |
| debug!("convert: item {} with id {}", it.ident, it.hir_id()); |
| let def_id = item_id.owner_id.def_id; |
| |
| match &it.kind { |
| // These don't define types. |
| hir::ItemKind::ExternCrate(_) |
| | hir::ItemKind::Use(..) |
| | hir::ItemKind::Macro(..) |
| | hir::ItemKind::Mod(_) |
| | hir::ItemKind::GlobalAsm(_) => {} |
| hir::ItemKind::ForeignMod { items, .. } => { |
| for item in *items { |
| let item = tcx.hir().foreign_item(item.id); |
| tcx.ensure().generics_of(item.owner_id); |
| tcx.ensure().type_of(item.owner_id); |
| tcx.ensure().predicates_of(item.owner_id); |
| match item.kind { |
| hir::ForeignItemKind::Fn(..) => { |
| tcx.ensure().codegen_fn_attrs(item.owner_id); |
| tcx.ensure().fn_sig(item.owner_id) |
| } |
| hir::ForeignItemKind::Static(..) => { |
| tcx.ensure().codegen_fn_attrs(item.owner_id); |
| let mut visitor = HirPlaceholderCollector::default(); |
| visitor.visit_foreign_item(item); |
| placeholder_type_error( |
| tcx, |
| None, |
| visitor.0, |
| false, |
| None, |
| "static variable", |
| ); |
| } |
| _ => (), |
| } |
| } |
| } |
| hir::ItemKind::Enum(..) => { |
| tcx.ensure().generics_of(def_id); |
| tcx.ensure().type_of(def_id); |
| tcx.ensure().predicates_of(def_id); |
| convert_enum_variant_types(tcx, def_id.to_def_id()); |
| } |
| hir::ItemKind::Impl { .. } => { |
| tcx.ensure().generics_of(def_id); |
| tcx.ensure().type_of(def_id); |
| tcx.ensure().impl_trait_ref(def_id); |
| tcx.ensure().predicates_of(def_id); |
| } |
| hir::ItemKind::Trait(..) => { |
| tcx.ensure().generics_of(def_id); |
| tcx.ensure().trait_def(def_id); |
| tcx.at(it.span).super_predicates_of(def_id); |
| tcx.ensure().predicates_of(def_id); |
| } |
| hir::ItemKind::TraitAlias(..) => { |
| tcx.ensure().generics_of(def_id); |
| tcx.at(it.span).implied_predicates_of(def_id); |
| tcx.at(it.span).super_predicates_of(def_id); |
| tcx.ensure().predicates_of(def_id); |
| } |
| hir::ItemKind::Struct(struct_def, _) | hir::ItemKind::Union(struct_def, _) => { |
| tcx.ensure().generics_of(def_id); |
| tcx.ensure().type_of(def_id); |
| tcx.ensure().predicates_of(def_id); |
| |
| for f in struct_def.fields() { |
| tcx.ensure().generics_of(f.def_id); |
| tcx.ensure().type_of(f.def_id); |
| tcx.ensure().predicates_of(f.def_id); |
| } |
| |
| if let Some(ctor_def_id) = struct_def.ctor_def_id() { |
| convert_variant_ctor(tcx, ctor_def_id); |
| } |
| } |
| |
| // Don't call `type_of` on opaque types, since that depends on type |
| // checking function bodies. `check_item_type` ensures that it's called |
| // instead. |
| hir::ItemKind::OpaqueTy(..) => { |
| tcx.ensure().generics_of(def_id); |
| tcx.ensure().predicates_of(def_id); |
| tcx.ensure().explicit_item_bounds(def_id); |
| tcx.ensure().item_bounds(def_id); |
| } |
| |
| hir::ItemKind::TyAlias(..) => { |
| tcx.ensure().generics_of(def_id); |
| tcx.ensure().type_of(def_id); |
| tcx.ensure().predicates_of(def_id); |
| } |
| |
| hir::ItemKind::Static(ty, ..) | hir::ItemKind::Const(ty, ..) => { |
| tcx.ensure().generics_of(def_id); |
| tcx.ensure().type_of(def_id); |
| tcx.ensure().predicates_of(def_id); |
| if !is_suggestable_infer_ty(ty) { |
| let mut visitor = HirPlaceholderCollector::default(); |
| visitor.visit_item(it); |
| placeholder_type_error(tcx, None, visitor.0, false, None, it.kind.descr()); |
| } |
| } |
| |
| hir::ItemKind::Fn(..) => { |
| tcx.ensure().generics_of(def_id); |
| tcx.ensure().type_of(def_id); |
| tcx.ensure().predicates_of(def_id); |
| tcx.ensure().fn_sig(def_id); |
| tcx.ensure().codegen_fn_attrs(def_id); |
| } |
| } |
| } |
| |
| fn convert_trait_item(tcx: TyCtxt<'_>, trait_item_id: hir::TraitItemId) { |
| let trait_item = tcx.hir().trait_item(trait_item_id); |
| let def_id = trait_item_id.owner_id; |
| tcx.ensure().generics_of(def_id); |
| |
| match trait_item.kind { |
| hir::TraitItemKind::Fn(..) => { |
| tcx.ensure().codegen_fn_attrs(def_id); |
| tcx.ensure().type_of(def_id); |
| tcx.ensure().fn_sig(def_id); |
| } |
| |
| hir::TraitItemKind::Const(.., Some(_)) => { |
| tcx.ensure().type_of(def_id); |
| } |
| |
| hir::TraitItemKind::Const(hir_ty, _) => { |
| tcx.ensure().type_of(def_id); |
| // Account for `const C: _;`. |
| let mut visitor = HirPlaceholderCollector::default(); |
| visitor.visit_trait_item(trait_item); |
| if !tcx.sess.diagnostic().has_stashed_diagnostic(hir_ty.span, StashKey::ItemNoType) { |
| placeholder_type_error(tcx, None, visitor.0, false, None, "constant"); |
| } |
| } |
| |
| hir::TraitItemKind::Type(_, Some(_)) => { |
| tcx.ensure().item_bounds(def_id); |
| tcx.ensure().type_of(def_id); |
| // Account for `type T = _;`. |
| let mut visitor = HirPlaceholderCollector::default(); |
| visitor.visit_trait_item(trait_item); |
| placeholder_type_error(tcx, None, visitor.0, false, None, "associated type"); |
| } |
| |
| hir::TraitItemKind::Type(_, None) => { |
| tcx.ensure().item_bounds(def_id); |
| // #74612: Visit and try to find bad placeholders |
| // even if there is no concrete type. |
| let mut visitor = HirPlaceholderCollector::default(); |
| visitor.visit_trait_item(trait_item); |
| |
| placeholder_type_error(tcx, None, visitor.0, false, None, "associated type"); |
| } |
| }; |
| |
| tcx.ensure().predicates_of(def_id); |
| } |
| |
| fn convert_impl_item(tcx: TyCtxt<'_>, impl_item_id: hir::ImplItemId) { |
| let def_id = impl_item_id.owner_id; |
| tcx.ensure().generics_of(def_id); |
| tcx.ensure().type_of(def_id); |
| tcx.ensure().predicates_of(def_id); |
| let impl_item = tcx.hir().impl_item(impl_item_id); |
| match impl_item.kind { |
| hir::ImplItemKind::Fn(..) => { |
| tcx.ensure().codegen_fn_attrs(def_id); |
| tcx.ensure().fn_sig(def_id); |
| } |
| hir::ImplItemKind::Type(_) => { |
| // Account for `type T = _;` |
| let mut visitor = HirPlaceholderCollector::default(); |
| visitor.visit_impl_item(impl_item); |
| |
| placeholder_type_error(tcx, None, visitor.0, false, None, "associated type"); |
| } |
| hir::ImplItemKind::Const(..) => {} |
| } |
| } |
| |
| fn convert_variant_ctor(tcx: TyCtxt<'_>, def_id: LocalDefId) { |
| tcx.ensure().generics_of(def_id); |
| tcx.ensure().type_of(def_id); |
| tcx.ensure().predicates_of(def_id); |
| } |
| |
| fn convert_enum_variant_types(tcx: TyCtxt<'_>, def_id: DefId) { |
| let def = tcx.adt_def(def_id); |
| let repr_type = def.repr().discr_type(); |
| let initial = repr_type.initial_discriminant(tcx); |
| let mut prev_discr = None::<Discr<'_>>; |
| |
| // fill the discriminant values and field types |
| for variant in def.variants() { |
| let wrapped_discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx)); |
| prev_discr = Some( |
| if let ty::VariantDiscr::Explicit(const_def_id) = variant.discr { |
| def.eval_explicit_discr(tcx, const_def_id) |
| } else if let Some(discr) = repr_type.disr_incr(tcx, prev_discr) { |
| Some(discr) |
| } else { |
| let span = tcx.def_span(variant.def_id); |
| tcx.sess.emit_err(errors::EnumDiscriminantOverflowed { |
| span, |
| discr: prev_discr.unwrap().to_string(), |
| item_name: tcx.item_name(variant.def_id), |
| wrapped_discr: wrapped_discr.to_string(), |
| }); |
| None |
| } |
| .unwrap_or(wrapped_discr), |
| ); |
| |
| for f in &variant.fields { |
| tcx.ensure().generics_of(f.did); |
| tcx.ensure().type_of(f.did); |
| tcx.ensure().predicates_of(f.did); |
| } |
| |
| // Convert the ctor, if any. This also registers the variant as |
| // an item. |
| if let Some(ctor_def_id) = variant.ctor_def_id() { |
| convert_variant_ctor(tcx, ctor_def_id.expect_local()); |
| } |
| } |
| } |
| |
| fn convert_variant( |
| tcx: TyCtxt<'_>, |
| variant_did: Option<LocalDefId>, |
| ident: Ident, |
| discr: ty::VariantDiscr, |
| def: &hir::VariantData<'_>, |
| adt_kind: ty::AdtKind, |
| parent_did: LocalDefId, |
| ) -> ty::VariantDef { |
| let mut seen_fields: FxHashMap<Ident, Span> = Default::default(); |
| let fields = def |
| .fields() |
| .iter() |
| .map(|f| { |
| let dup_span = seen_fields.get(&f.ident.normalize_to_macros_2_0()).cloned(); |
| if let Some(prev_span) = dup_span { |
| tcx.sess.emit_err(errors::FieldAlreadyDeclared { |
| field_name: f.ident, |
| span: f.span, |
| prev_span, |
| }); |
| } else { |
| seen_fields.insert(f.ident.normalize_to_macros_2_0(), f.span); |
| } |
| |
| ty::FieldDef { |
| did: f.def_id.to_def_id(), |
| name: f.ident.name, |
| vis: tcx.visibility(f.def_id), |
| } |
| }) |
| .collect(); |
| let recovered = match def { |
| hir::VariantData::Struct(_, r) => *r, |
| _ => false, |
| }; |
| ty::VariantDef::new( |
| ident.name, |
| variant_did.map(LocalDefId::to_def_id), |
| def.ctor().map(|(kind, _, def_id)| (kind, def_id.to_def_id())), |
| discr, |
| fields, |
| adt_kind, |
| parent_did.to_def_id(), |
| recovered, |
| adt_kind == AdtKind::Struct && tcx.has_attr(parent_did, sym::non_exhaustive) |
| || variant_did |
| .is_some_and(|variant_did| tcx.has_attr(variant_did, sym::non_exhaustive)), |
| ) |
| } |
| |
| fn adt_def(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::AdtDef<'_> { |
| use rustc_hir::*; |
| |
| let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); |
| let Node::Item(item) = tcx.hir().get(hir_id) else { |
| bug!(); |
| }; |
| |
| let repr = tcx.repr_options_of_def(def_id.to_def_id()); |
| let (kind, variants) = match &item.kind { |
| ItemKind::Enum(def, _) => { |
| let mut distance_from_explicit = 0; |
| let variants = def |
| .variants |
| .iter() |
| .map(|v| { |
| let discr = if let Some(e) = &v.disr_expr { |
| distance_from_explicit = 0; |
| ty::VariantDiscr::Explicit(e.def_id.to_def_id()) |
| } else { |
| ty::VariantDiscr::Relative(distance_from_explicit) |
| }; |
| distance_from_explicit += 1; |
| |
| convert_variant( |
| tcx, |
| Some(v.def_id), |
| v.ident, |
| discr, |
| &v.data, |
| AdtKind::Enum, |
| def_id, |
| ) |
| }) |
| .collect(); |
| |
| (AdtKind::Enum, variants) |
| } |
| ItemKind::Struct(def, _) | ItemKind::Union(def, _) => { |
| let adt_kind = match item.kind { |
| ItemKind::Struct(..) => AdtKind::Struct, |
| _ => AdtKind::Union, |
| }; |
| let variants = std::iter::once(convert_variant( |
| tcx, |
| None, |
| item.ident, |
| ty::VariantDiscr::Relative(0), |
| def, |
| adt_kind, |
| def_id, |
| )) |
| .collect(); |
| |
| (adt_kind, variants) |
| } |
| _ => bug!(), |
| }; |
| tcx.mk_adt_def(def_id.to_def_id(), kind, variants, repr) |
| } |
| |
| fn trait_def(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::TraitDef { |
| let item = tcx.hir().expect_item(def_id); |
| |
| let (is_auto, unsafety, items) = match item.kind { |
| hir::ItemKind::Trait(is_auto, unsafety, .., items) => { |
| (is_auto == hir::IsAuto::Yes, unsafety, items) |
| } |
| hir::ItemKind::TraitAlias(..) => (false, hir::Unsafety::Normal, &[][..]), |
| _ => span_bug!(item.span, "trait_def_of_item invoked on non-trait"), |
| }; |
| |
| let paren_sugar = tcx.has_attr(def_id, sym::rustc_paren_sugar); |
| if paren_sugar && !tcx.features().unboxed_closures { |
| tcx.sess.emit_err(errors::ParenSugarAttribute { span: item.span }); |
| } |
| |
| let is_marker = tcx.has_attr(def_id, sym::marker); |
| let rustc_coinductive = tcx.has_attr(def_id, sym::rustc_coinductive); |
| let skip_array_during_method_dispatch = |
| tcx.has_attr(def_id, sym::rustc_skip_array_during_method_dispatch); |
| let specialization_kind = if tcx.has_attr(def_id, sym::rustc_unsafe_specialization_marker) { |
| ty::trait_def::TraitSpecializationKind::Marker |
| } else if tcx.has_attr(def_id, sym::rustc_specialization_trait) { |
| ty::trait_def::TraitSpecializationKind::AlwaysApplicable |
| } else { |
| ty::trait_def::TraitSpecializationKind::None |
| }; |
| let must_implement_one_of = tcx |
| .get_attr(def_id, sym::rustc_must_implement_one_of) |
| // Check that there are at least 2 arguments of `#[rustc_must_implement_one_of]` |
| // and that they are all identifiers |
| .and_then(|attr| match attr.meta_item_list() { |
| Some(items) if items.len() < 2 => { |
| tcx.sess.emit_err(errors::MustImplementOneOfAttribute { span: attr.span }); |
| |
| None |
| } |
| Some(items) => items |
| .into_iter() |
| .map(|item| item.ident().ok_or(item.span())) |
| .collect::<Result<Box<[_]>, _>>() |
| .map_err(|span| { |
| tcx.sess.emit_err(errors::MustBeNameOfAssociatedFunction { span }); |
| }) |
| .ok() |
| .zip(Some(attr.span)), |
| // Error is reported by `rustc_attr!` |
| None => None, |
| }) |
| // Check that all arguments of `#[rustc_must_implement_one_of]` reference |
| // functions in the trait with default implementations |
| .and_then(|(list, attr_span)| { |
| let errors = list.iter().filter_map(|ident| { |
| let item = items.iter().find(|item| item.ident == *ident); |
| |
| match item { |
| Some(item) if matches!(item.kind, hir::AssocItemKind::Fn { .. }) => { |
| if !tcx.impl_defaultness(item.id.owner_id).has_value() { |
| tcx.sess.emit_err(errors::FunctionNotHaveDefaultImplementation { |
| span: item.span, |
| note_span: attr_span, |
| }); |
| |
| return Some(()); |
| } |
| |
| return None; |
| } |
| Some(item) => { |
| tcx.sess.emit_err(errors::MustImplementNotFunction { |
| span: item.span, |
| span_note: errors::MustImplementNotFunctionSpanNote { span: attr_span }, |
| note: errors::MustImplementNotFunctionNote {}, |
| }); |
| } |
| None => { |
| tcx.sess.emit_err(errors::FunctionNotFoundInTrait { span: ident.span }); |
| } |
| } |
| |
| Some(()) |
| }); |
| |
| (errors.count() == 0).then_some(list) |
| }) |
| // Check for duplicates |
| .and_then(|list| { |
| let mut set: FxHashMap<Symbol, Span> = FxHashMap::default(); |
| let mut no_dups = true; |
| |
| for ident in &*list { |
| if let Some(dup) = set.insert(ident.name, ident.span) { |
| tcx.sess |
| .emit_err(errors::FunctionNamesDuplicated { spans: vec![dup, ident.span] }); |
| |
| no_dups = false; |
| } |
| } |
| |
| no_dups.then_some(list) |
| }); |
| |
| ty::TraitDef { |
| def_id: def_id.to_def_id(), |
| unsafety, |
| paren_sugar, |
| has_auto_impl: is_auto, |
| is_marker, |
| is_coinductive: rustc_coinductive || is_auto, |
| skip_array_during_method_dispatch, |
| specialization_kind, |
| must_implement_one_of, |
| } |
| } |
| |
| fn are_suggestable_generic_args(generic_args: &[hir::GenericArg<'_>]) -> bool { |
| generic_args.iter().any(|arg| match arg { |
| hir::GenericArg::Type(ty) => is_suggestable_infer_ty(ty), |
| hir::GenericArg::Infer(_) => true, |
| _ => false, |
| }) |
| } |
| |
| /// Whether `ty` is a type with `_` placeholders that can be inferred. Used in diagnostics only to |
| /// use inference to provide suggestions for the appropriate type if possible. |
| fn is_suggestable_infer_ty(ty: &hir::Ty<'_>) -> bool { |
| debug!(?ty); |
| use hir::TyKind::*; |
| match &ty.kind { |
| Infer => true, |
| Slice(ty) => is_suggestable_infer_ty(ty), |
| Array(ty, length) => { |
| is_suggestable_infer_ty(ty) || matches!(length, hir::ArrayLen::Infer(_, _)) |
| } |
| Tup(tys) => tys.iter().any(is_suggestable_infer_ty), |
| Ptr(mut_ty) | Ref(_, mut_ty) => is_suggestable_infer_ty(mut_ty.ty), |
| OpaqueDef(_, generic_args, _) => are_suggestable_generic_args(generic_args), |
| Path(hir::QPath::TypeRelative(ty, segment)) => { |
| is_suggestable_infer_ty(ty) || are_suggestable_generic_args(segment.args().args) |
| } |
| Path(hir::QPath::Resolved(ty_opt, hir::Path { segments, .. })) => { |
| ty_opt.is_some_and(is_suggestable_infer_ty) |
| || segments.iter().any(|segment| are_suggestable_generic_args(segment.args().args)) |
| } |
| _ => false, |
| } |
| } |
| |
| pub fn get_infer_ret_ty<'hir>(output: &'hir hir::FnRetTy<'hir>) -> Option<&'hir hir::Ty<'hir>> { |
| if let hir::FnRetTy::Return(ty) = output { |
| if is_suggestable_infer_ty(ty) { |
| return Some(&*ty); |
| } |
| } |
| None |
| } |
| |
| #[instrument(level = "debug", skip(tcx))] |
| fn fn_sig(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::EarlyBinder<ty::PolyFnSig<'_>> { |
| use rustc_hir::Node::*; |
| use rustc_hir::*; |
| |
| let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); |
| |
| let icx = ItemCtxt::new(tcx, def_id); |
| |
| let output = match tcx.hir().get(hir_id) { |
| TraitItem(hir::TraitItem { |
| kind: TraitItemKind::Fn(sig, TraitFn::Provided(_)), |
| generics, |
| .. |
| }) |
| | Item(hir::Item { kind: ItemKind::Fn(sig, generics, _), .. }) => { |
| infer_return_ty_for_fn_sig(tcx, sig, generics, def_id, &icx) |
| } |
| |
| ImplItem(hir::ImplItem { kind: ImplItemKind::Fn(sig, _), generics, .. }) => { |
| // Do not try to infer the return type for a impl method coming from a trait |
| if let Item(hir::Item { kind: ItemKind::Impl(i), .. }) = |
| tcx.hir().get_parent(hir_id) |
| && i.of_trait.is_some() |
| { |
| icx.astconv().ty_of_fn( |
| hir_id, |
| sig.header.unsafety, |
| sig.header.abi, |
| sig.decl, |
| Some(generics), |
| None, |
| ) |
| } else { |
| infer_return_ty_for_fn_sig(tcx, sig, generics, def_id, &icx) |
| } |
| } |
| |
| TraitItem(hir::TraitItem { |
| kind: TraitItemKind::Fn(FnSig { header, decl, span: _ }, _), |
| generics, |
| .. |
| }) => { |
| icx.astconv().ty_of_fn(hir_id, header.unsafety, header.abi, decl, Some(generics), None) |
| } |
| |
| ForeignItem(&hir::ForeignItem { kind: ForeignItemKind::Fn(fn_decl, _, _), .. }) => { |
| let abi = tcx.hir().get_foreign_abi(hir_id); |
| compute_sig_of_foreign_fn_decl(tcx, def_id, fn_decl, abi) |
| } |
| |
| Ctor(data) | Variant(hir::Variant { data, .. }) if data.ctor().is_some() => { |
| let ty = tcx.type_of(tcx.hir().get_parent_item(hir_id)).subst_identity(); |
| let inputs = data.fields().iter().map(|f| tcx.type_of(f.def_id).subst_identity()); |
| ty::Binder::dummy(tcx.mk_fn_sig( |
| inputs, |
| ty, |
| false, |
| hir::Unsafety::Normal, |
| abi::Abi::Rust, |
| )) |
| } |
| |
| Expr(&hir::Expr { kind: hir::ExprKind::Closure { .. }, .. }) => { |
| // Closure signatures are not like other function |
| // signatures and cannot be accessed through `fn_sig`. For |
| // example, a closure signature excludes the `self` |
| // argument. In any case they are embedded within the |
| // closure type as part of the `ClosureSubsts`. |
| // |
| // To get the signature of a closure, you should use the |
| // `sig` method on the `ClosureSubsts`: |
| // |
| // substs.as_closure().sig(def_id, tcx) |
| bug!( |
| "to get the signature of a closure, use `substs.as_closure().sig()` not `fn_sig()`", |
| ); |
| } |
| |
| x => { |
| bug!("unexpected sort of node in fn_sig(): {:?}", x); |
| } |
| }; |
| ty::EarlyBinder(output) |
| } |
| |
| fn infer_return_ty_for_fn_sig<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| sig: &hir::FnSig<'_>, |
| generics: &hir::Generics<'_>, |
| def_id: LocalDefId, |
| icx: &ItemCtxt<'tcx>, |
| ) -> ty::PolyFnSig<'tcx> { |
| let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); |
| |
| match get_infer_ret_ty(&sig.decl.output) { |
| Some(ty) => { |
| let fn_sig = tcx.typeck(def_id).liberated_fn_sigs()[hir_id]; |
| // Typeck doesn't expect erased regions to be returned from `type_of`. |
| let fn_sig = tcx.fold_regions(fn_sig, |r, _| match *r { |
| ty::ReErased => tcx.lifetimes.re_static, |
| _ => r, |
| }); |
| |
| let mut visitor = HirPlaceholderCollector::default(); |
| visitor.visit_ty(ty); |
| |
| let mut diag = bad_placeholder(tcx, visitor.0, "return type"); |
| let ret_ty = fn_sig.output(); |
| // Don't leak types into signatures unless they're nameable! |
| // For example, if a function returns itself, we don't want that |
| // recursive function definition to leak out into the fn sig. |
| let mut should_recover = false; |
| |
| if let Some(ret_ty) = ret_ty.make_suggestable(tcx, false) { |
| diag.span_suggestion( |
| ty.span, |
| "replace with the correct return type", |
| ret_ty, |
| Applicability::MachineApplicable, |
| ); |
| should_recover = true; |
| } else if let Some(sugg) = suggest_impl_trait(tcx, ret_ty, ty.span, def_id) { |
| diag.span_suggestion( |
| ty.span, |
| "replace with an appropriate return type", |
| sugg, |
| Applicability::MachineApplicable, |
| ); |
| } else if ret_ty.is_closure() { |
| diag.help("consider using an `Fn`, `FnMut`, or `FnOnce` trait bound"); |
| } |
| // Also note how `Fn` traits work just in case! |
| if ret_ty.is_closure() { |
| diag.note( |
| "for more information on `Fn` traits and closure types, see \ |
| https://doc.rust-lang.org/book/ch13-01-closures.html", |
| ); |
| } |
| |
| let guar = diag.emit(); |
| |
| if should_recover { |
| ty::Binder::dummy(fn_sig) |
| } else { |
| ty::Binder::dummy(tcx.mk_fn_sig( |
| fn_sig.inputs().iter().copied(), |
| tcx.ty_error(guar), |
| fn_sig.c_variadic, |
| fn_sig.unsafety, |
| fn_sig.abi, |
| )) |
| } |
| } |
| None => icx.astconv().ty_of_fn( |
| hir_id, |
| sig.header.unsafety, |
| sig.header.abi, |
| sig.decl, |
| Some(generics), |
| None, |
| ), |
| } |
| } |
| |
| fn suggest_impl_trait<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| ret_ty: Ty<'tcx>, |
| span: Span, |
| def_id: LocalDefId, |
| ) -> Option<String> { |
| let format_as_assoc: fn(_, _, _, _, _) -> _ = |
| |tcx: TyCtxt<'tcx>, |
| _: ty::SubstsRef<'tcx>, |
| trait_def_id: DefId, |
| assoc_item_def_id: DefId, |
| item_ty: Ty<'tcx>| { |
| let trait_name = tcx.item_name(trait_def_id); |
| let assoc_name = tcx.item_name(assoc_item_def_id); |
| Some(format!("impl {trait_name}<{assoc_name} = {item_ty}>")) |
| }; |
| let format_as_parenthesized: fn(_, _, _, _, _) -> _ = |
| |tcx: TyCtxt<'tcx>, |
| substs: ty::SubstsRef<'tcx>, |
| trait_def_id: DefId, |
| _: DefId, |
| item_ty: Ty<'tcx>| { |
| let trait_name = tcx.item_name(trait_def_id); |
| let args_tuple = substs.type_at(1); |
| let ty::Tuple(types) = *args_tuple.kind() else { return None; }; |
| let types = types.make_suggestable(tcx, false)?; |
| let maybe_ret = |
| if item_ty.is_unit() { String::new() } else { format!(" -> {item_ty}") }; |
| Some(format!( |
| "impl {trait_name}({}){maybe_ret}", |
| types.iter().map(|ty| ty.to_string()).collect::<Vec<_>>().join(", ") |
| )) |
| }; |
| |
| for (trait_def_id, assoc_item_def_id, formatter) in [ |
| ( |
| tcx.get_diagnostic_item(sym::Iterator), |
| tcx.get_diagnostic_item(sym::IteratorItem), |
| format_as_assoc, |
| ), |
| ( |
| tcx.lang_items().future_trait(), |
| tcx.get_diagnostic_item(sym::FutureOutput), |
| format_as_assoc, |
| ), |
| (tcx.lang_items().fn_trait(), tcx.lang_items().fn_once_output(), format_as_parenthesized), |
| ( |
| tcx.lang_items().fn_mut_trait(), |
| tcx.lang_items().fn_once_output(), |
| format_as_parenthesized, |
| ), |
| ( |
| tcx.lang_items().fn_once_trait(), |
| tcx.lang_items().fn_once_output(), |
| format_as_parenthesized, |
| ), |
| ] { |
| let Some(trait_def_id) = trait_def_id else { continue; }; |
| let Some(assoc_item_def_id) = assoc_item_def_id else { continue; }; |
| if tcx.def_kind(assoc_item_def_id) != DefKind::AssocTy { |
| continue; |
| } |
| let param_env = tcx.param_env(def_id); |
| let infcx = tcx.infer_ctxt().build(); |
| let substs = ty::InternalSubsts::for_item(tcx, trait_def_id, |param, _| { |
| if param.index == 0 { ret_ty.into() } else { infcx.var_for_def(span, param) } |
| }); |
| if !infcx.type_implements_trait(trait_def_id, substs, param_env).must_apply_modulo_regions() |
| { |
| continue; |
| } |
| let ocx = ObligationCtxt::new_in_snapshot(&infcx); |
| let item_ty = ocx.normalize( |
| &ObligationCause::misc(span, def_id), |
| param_env, |
| tcx.mk_projection(assoc_item_def_id, substs), |
| ); |
| // FIXME(compiler-errors): We may benefit from resolving regions here. |
| if ocx.select_where_possible().is_empty() |
| && let item_ty = infcx.resolve_vars_if_possible(item_ty) |
| && let Some(item_ty) = item_ty.make_suggestable(tcx, false) |
| && let Some(sugg) = formatter(tcx, infcx.resolve_vars_if_possible(substs), trait_def_id, assoc_item_def_id, item_ty) |
| { |
| return Some(sugg); |
| } |
| } |
| None |
| } |
| |
| fn impl_trait_ref( |
| tcx: TyCtxt<'_>, |
| def_id: LocalDefId, |
| ) -> Option<ty::EarlyBinder<ty::TraitRef<'_>>> { |
| let icx = ItemCtxt::new(tcx, def_id); |
| let impl_ = tcx.hir().expect_item(def_id).expect_impl(); |
| impl_ |
| .of_trait |
| .as_ref() |
| .map(|ast_trait_ref| { |
| let selfty = tcx.type_of(def_id).subst_identity(); |
| icx.astconv().instantiate_mono_trait_ref( |
| ast_trait_ref, |
| selfty, |
| check_impl_constness(tcx, impl_.constness, ast_trait_ref), |
| ) |
| }) |
| .map(ty::EarlyBinder) |
| } |
| |
| fn check_impl_constness( |
| tcx: TyCtxt<'_>, |
| constness: hir::Constness, |
| ast_trait_ref: &hir::TraitRef<'_>, |
| ) -> ty::BoundConstness { |
| match constness { |
| hir::Constness::Const => { |
| if let Some(trait_def_id) = ast_trait_ref.trait_def_id() && !tcx.has_attr(trait_def_id, sym::const_trait) { |
| let trait_name = tcx.item_name(trait_def_id).to_string(); |
| tcx.sess.emit_err(errors::ConstImplForNonConstTrait { |
| trait_ref_span: ast_trait_ref.path.span, |
| trait_name, |
| local_trait_span: trait_def_id.as_local().map(|_| tcx.def_span(trait_def_id).shrink_to_lo()), |
| marking: (), |
| adding: (), |
| }); |
| ty::BoundConstness::NotConst |
| } else { |
| ty::BoundConstness::ConstIfConst |
| } |
| }, |
| hir::Constness::NotConst => ty::BoundConstness::NotConst, |
| } |
| } |
| |
| fn impl_polarity(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::ImplPolarity { |
| let is_rustc_reservation = tcx.has_attr(def_id, sym::rustc_reservation_impl); |
| let item = tcx.hir().expect_item(def_id); |
| match &item.kind { |
| hir::ItemKind::Impl(hir::Impl { |
| polarity: hir::ImplPolarity::Negative(span), |
| of_trait, |
| .. |
| }) => { |
| if is_rustc_reservation { |
| let span = span.to(of_trait.as_ref().map_or(*span, |t| t.path.span)); |
| tcx.sess.span_err(span, "reservation impls can't be negative"); |
| } |
| ty::ImplPolarity::Negative |
| } |
| hir::ItemKind::Impl(hir::Impl { |
| polarity: hir::ImplPolarity::Positive, |
| of_trait: None, |
| .. |
| }) => { |
| if is_rustc_reservation { |
| tcx.sess.span_err(item.span, "reservation impls can't be inherent"); |
| } |
| ty::ImplPolarity::Positive |
| } |
| hir::ItemKind::Impl(hir::Impl { |
| polarity: hir::ImplPolarity::Positive, |
| of_trait: Some(_), |
| .. |
| }) => { |
| if is_rustc_reservation { |
| ty::ImplPolarity::Reservation |
| } else { |
| ty::ImplPolarity::Positive |
| } |
| } |
| item => bug!("impl_polarity: {:?} not an impl", item), |
| } |
| } |
| |
| /// Returns the early-bound lifetimes declared in this generics |
| /// listing. For anything other than fns/methods, this is just all |
| /// the lifetimes that are declared. For fns or methods, we have to |
| /// screen out those that do not appear in any where-clauses etc using |
| /// `resolve_lifetime::early_bound_lifetimes`. |
| fn early_bound_lifetimes_from_generics<'a, 'tcx: 'a>( |
| tcx: TyCtxt<'tcx>, |
| generics: &'a hir::Generics<'a>, |
| ) -> impl Iterator<Item = &'a hir::GenericParam<'a>> + Captures<'tcx> { |
| generics.params.iter().filter(move |param| match param.kind { |
| GenericParamKind::Lifetime { .. } => !tcx.is_late_bound(param.hir_id), |
| _ => false, |
| }) |
| } |
| |
| /// Returns a list of type predicates for the definition with ID `def_id`, including inferred |
| /// lifetime constraints. This includes all predicates returned by `explicit_predicates_of`, plus |
| /// inferred constraints concerning which regions outlive other regions. |
| #[instrument(level = "debug", skip(tcx))] |
| fn predicates_defined_on(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicates<'_> { |
| let mut result = tcx.explicit_predicates_of(def_id); |
| debug!("predicates_defined_on: explicit_predicates_of({:?}) = {:?}", def_id, result,); |
| let inferred_outlives = tcx.inferred_outlives_of(def_id); |
| if !inferred_outlives.is_empty() { |
| debug!( |
| "predicates_defined_on: inferred_outlives_of({:?}) = {:?}", |
| def_id, inferred_outlives, |
| ); |
| let inferred_outlives_iter = |
| inferred_outlives.iter().map(|(clause, span)| ((*clause).to_predicate(tcx), *span)); |
| if result.predicates.is_empty() { |
| result.predicates = tcx.arena.alloc_from_iter(inferred_outlives_iter); |
| } else { |
| result.predicates = tcx.arena.alloc_from_iter( |
| result.predicates.into_iter().copied().chain(inferred_outlives_iter), |
| ); |
| } |
| } |
| |
| debug!("predicates_defined_on({:?}) = {:?}", def_id, result); |
| result |
| } |
| |
| fn compute_sig_of_foreign_fn_decl<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| def_id: LocalDefId, |
| decl: &'tcx hir::FnDecl<'tcx>, |
| abi: abi::Abi, |
| ) -> ty::PolyFnSig<'tcx> { |
| let unsafety = if abi == abi::Abi::RustIntrinsic { |
| intrinsic_operation_unsafety(tcx, def_id.to_def_id()) |
| } else { |
| hir::Unsafety::Unsafe |
| }; |
| let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); |
| let fty = |
| ItemCtxt::new(tcx, def_id).astconv().ty_of_fn(hir_id, unsafety, abi, decl, None, None); |
| |
| // Feature gate SIMD types in FFI, since I am not sure that the |
| // ABIs are handled at all correctly. -huonw |
| if abi != abi::Abi::RustIntrinsic |
| && abi != abi::Abi::PlatformIntrinsic |
| && !tcx.features().simd_ffi |
| { |
| let check = |ast_ty: &hir::Ty<'_>, ty: Ty<'_>| { |
| if ty.is_simd() { |
| let snip = tcx |
| .sess |
| .source_map() |
| .span_to_snippet(ast_ty.span) |
| .map_or_else(|_| String::new(), |s| format!(" `{}`", s)); |
| tcx.sess.emit_err(errors::SIMDFFIHighlyExperimental { span: ast_ty.span, snip }); |
| } |
| }; |
| for (input, ty) in iter::zip(decl.inputs, fty.inputs().skip_binder()) { |
| check(input, *ty) |
| } |
| if let hir::FnRetTy::Return(ty) = decl.output { |
| check(ty, fty.output().skip_binder()) |
| } |
| } |
| |
| fty |
| } |
| |
| fn generator_kind(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option<hir::GeneratorKind> { |
| match tcx.hir().get_by_def_id(def_id) { |
| Node::Expr(&rustc_hir::Expr { |
| kind: rustc_hir::ExprKind::Closure(&rustc_hir::Closure { body, .. }), |
| .. |
| }) => tcx.hir().body(body).generator_kind(), |
| _ => None, |
| } |
| } |
| |
| fn is_type_alias_impl_trait<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> bool { |
| match tcx.hir().get_by_def_id(def_id) { |
| Node::Item(hir::Item { kind: hir::ItemKind::OpaqueTy(opaque), .. }) => { |
| matches!(opaque.origin, hir::OpaqueTyOrigin::TyAlias { .. }) |
| } |
| _ => bug!("tried getting opaque_ty_origin for non-opaque: {:?}", def_id), |
| } |
| } |
