| // ignore-tidy-filelength |
| //! "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. |
| |
| // ignore-tidy-filelength |
| |
| use crate::astconv::{AstConv, SizedByDefault}; |
| use crate::bounds::Bounds; |
| use crate::check::intrinsic::intrinsic_operation_unsafety; |
| use crate::constrained_generic_params as cgp; |
| use crate::errors; |
| use crate::middle::resolve_lifetime as rl; |
| use rustc_ast as ast; |
| use rustc_ast::{MetaItemKind, NestedMetaItem}; |
| use rustc_attr::{list_contains_name, InlineAttr, InstructionSetAttr, OptimizeAttr}; |
| use rustc_data_structures::captures::Captures; |
| use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexSet}; |
| use rustc_errors::{struct_span_err, Applicability}; |
| use rustc_hir as hir; |
| use rustc_hir::def::{CtorKind, DefKind, Res}; |
| use rustc_hir::def_id::{DefId, LocalDefId, LOCAL_CRATE}; |
| use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor}; |
| use rustc_hir::weak_lang_items; |
| use rustc_hir::{GenericParamKind, HirId, Node}; |
| use rustc_middle::hir::map::blocks::FnLikeNode; |
| use rustc_middle::hir::map::Map; |
| use rustc_middle::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs}; |
| use rustc_middle::mir::mono::Linkage; |
| use rustc_middle::ty::query::Providers; |
| use rustc_middle::ty::subst::InternalSubsts; |
| use rustc_middle::ty::util::Discr; |
| use rustc_middle::ty::util::IntTypeExt; |
| use rustc_middle::ty::{self, AdtKind, Const, DefIdTree, ToPolyTraitRef, Ty, TyCtxt}; |
| use rustc_middle::ty::{ReprOptions, ToPredicate, WithConstness}; |
| use rustc_session::lint; |
| use rustc_session::parse::feature_err; |
| use rustc_span::symbol::{kw, sym, Ident, Symbol}; |
| use rustc_span::{Span, DUMMY_SP}; |
| use rustc_target::spec::{abi, SanitizerSet}; |
| use rustc_trait_selection::traits::error_reporting::suggestions::NextTypeParamName; |
| use std::iter; |
| |
| mod item_bounds; |
| mod type_of; |
| |
| struct OnlySelfBounds(bool); |
| |
| /////////////////////////////////////////////////////////////////////////// |
| // 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 }.as_deep_visitor(), |
| ); |
| } |
| |
| pub fn provide(providers: &mut Providers) { |
| *providers = Providers { |
| opt_const_param_of: type_of::opt_const_param_of, |
| type_of: type_of::type_of, |
| item_bounds: item_bounds::item_bounds, |
| explicit_item_bounds: item_bounds::explicit_item_bounds, |
| generics_of, |
| predicates_of, |
| predicates_defined_on, |
| projection_ty_from_predicates, |
| explicit_predicates_of, |
| super_predicates_of, |
| super_predicates_that_define_assoc_type, |
| trait_explicit_predicates_and_bounds, |
| type_param_predicates, |
| trait_def, |
| adt_def, |
| fn_sig, |
| impl_trait_ref, |
| impl_polarity, |
| is_foreign_item, |
| static_mutability, |
| generator_kind, |
| codegen_fn_attrs, |
| collect_mod_item_types, |
| ..*providers |
| }; |
| } |
| |
| /////////////////////////////////////////////////////////////////////////// |
| |
| /// Context specific to some particular item. This is what implements |
| /// `AstConv`. It 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: DefId, |
| } |
| |
| /////////////////////////////////////////////////////////////////////////// |
| |
| #[derive(Default)] |
| crate struct PlaceholderHirTyCollector(crate Vec<Span>); |
| |
| impl<'v> Visitor<'v> for PlaceholderHirTyCollector { |
| type Map = intravisit::ErasedMap<'v>; |
| |
| fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> { |
| NestedVisitorMap::None |
| } |
| 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) |
| } |
| } |
| |
| 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. |
| crate fn placeholder_type_error( |
| tcx: TyCtxt<'tcx>, |
| span: Option<Span>, |
| generics: &[hir::GenericParam<'_>], |
| placeholder_types: Vec<Span>, |
| suggest: bool, |
| hir_ty: Option<&hir::Ty<'_>>, |
| ) { |
| if placeholder_types.is_empty() { |
| return; |
| } |
| |
| let type_name = generics.next_type_param_name(None); |
| let mut sugg: Vec<_> = |
| placeholder_types.iter().map(|sp| (*sp, (*type_name).to_string())).collect(); |
| |
| if generics.is_empty() { |
| if let Some(span) = span { |
| sugg.push((span, format!("<{}>", type_name))); |
| } |
| } else if let Some(arg) = generics |
| .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 { |
| let last = generics.iter().last().unwrap(); |
| sugg.push(( |
| // Account for bounds, we want `fn foo<T: E, K>(_: K)` not `fn foo<T, K: E>(_: K)`. |
| last.bounds_span().unwrap_or(last.span).shrink_to_hi(), |
| format!(", {}", type_name), |
| )); |
| } |
| |
| let mut err = bad_placeholder_type(tcx, placeholder_types); |
| |
| // Suggest, but only if it is not a function in const or static |
| if suggest { |
| let mut is_fn = false; |
| let mut is_const = false; |
| let mut is_static = false; |
| |
| if let Some(hir_ty) = hir_ty { |
| if let hir::TyKind::BareFn(_) = hir_ty.kind { |
| is_fn = true; |
| |
| // Check if parent is const or static |
| let parent_id = tcx.hir().get_parent_node(hir_ty.hir_id); |
| let parent_node = tcx.hir().get(parent_id); |
| |
| if let hir::Node::Item(item) = parent_node { |
| if let hir::ItemKind::Const(_, _) = item.kind { |
| is_const = true; |
| } else if let hir::ItemKind::Static(_, _, _) = item.kind { |
| is_static = true; |
| } |
| } |
| } |
| } |
| |
| // if function is wrapped around a const or static, |
| // then don't show the suggestion |
| if !(is_fn && (is_const || is_static)) { |
| err.multipart_suggestion( |
| "use type parameters instead", |
| sugg, |
| Applicability::HasPlaceholders, |
| ); |
| } |
| } |
| err.emit(); |
| } |
| |
| fn reject_placeholder_type_signatures_in_item(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 = PlaceholderHirTyCollector::default(); |
| visitor.visit_item(item); |
| |
| placeholder_type_error(tcx, Some(generics.span), generics.params, visitor.0, suggest, None); |
| } |
| |
| impl Visitor<'tcx> for CollectItemTypesVisitor<'tcx> { |
| type Map = Map<'tcx>; |
| |
| fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> { |
| NestedVisitorMap::OnlyBodies(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(_), .. } => { |
| let def_id = self.tcx.hir().local_def_id(param.hir_id); |
| self.tcx.ensure().type_of(def_id); |
| } |
| hir::GenericParamKind::Type { .. } => {} |
| hir::GenericParamKind::Const { default, .. } => { |
| let def_id = self.tcx.hir().local_def_id(param.hir_id); |
| self.tcx.ensure().type_of(def_id); |
| if let Some(default) = default { |
| let default_def_id = self.tcx.hir().local_def_id(default.hir_id); |
| // need to store default and type of default |
| self.tcx.ensure().type_of(default_def_id); |
| self.tcx.ensure().const_param_default(def_id); |
| } |
| } |
| } |
| } |
| intravisit::walk_generics(self, generics); |
| } |
| |
| fn visit_expr(&mut self, expr: &'tcx hir::Expr<'tcx>) { |
| if let hir::ExprKind::Closure(..) = expr.kind { |
| let def_id = self.tcx.hir().local_def_id(expr.hir_id); |
| self.tcx.ensure().generics_of(def_id); |
| self.tcx.ensure().type_of(def_id); |
| } |
| 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_type( |
| tcx: TyCtxt<'tcx>, |
| mut spans: Vec<Span>, |
| ) -> rustc_errors::DiagnosticBuilder<'tcx> { |
| spans.sort(); |
| let mut err = struct_span_err!( |
| tcx.sess, |
| spans.clone(), |
| E0121, |
| "the type placeholder `_` is not allowed within types on item signatures", |
| ); |
| for span in spans { |
| err.span_label(span, "not allowed in type signatures"); |
| } |
| err |
| } |
| |
| impl ItemCtxt<'tcx> { |
| pub fn new(tcx: TyCtxt<'tcx>, item_def_id: DefId) -> ItemCtxt<'tcx> { |
| ItemCtxt { tcx, item_def_id } |
| } |
| |
| pub fn to_ty(&self, ast_ty: &hir::Ty<'_>) -> Ty<'tcx> { |
| <dyn AstConv<'_>>::ast_ty_to_ty(self, ast_ty) |
| } |
| |
| pub fn hir_id(&self) -> hir::HirId { |
| self.tcx.hir().local_def_id_to_hir_id(self.item_def_id.expect_local()) |
| } |
| |
| pub fn node(&self) -> hir::Node<'tcx> { |
| self.tcx.hir().get(self.hir_id()) |
| } |
| } |
| |
| impl AstConv<'tcx> for ItemCtxt<'tcx> { |
| fn tcx(&self) -> TyCtxt<'tcx> { |
| self.tcx |
| } |
| |
| fn item_def_id(&self) -> Option<DefId> { |
| Some(self.item_def_id) |
| } |
| |
| fn default_constness_for_trait_bounds(&self) -> hir::Constness { |
| if let Some(fn_like) = FnLikeNode::from_node(self.node()) { |
| fn_like.constness() |
| } else { |
| hir::Constness::NotConst |
| } |
| } |
| |
| fn get_type_parameter_bounds( |
| &self, |
| span: Span, |
| def_id: DefId, |
| assoc_name: Ident, |
| ) -> ty::GenericPredicates<'tcx> { |
| self.tcx.at(span).type_param_predicates(( |
| self.item_def_id, |
| def_id.expect_local(), |
| 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, |
| ) -> &'tcx Const<'tcx> { |
| bad_placeholder_type(self.tcx(), vec![span]).emit(); |
| // Typeck doesn't expect erased regions to be returned from `type_of`. |
| let ty = self.tcx.fold_regions(ty, &mut false, |r, _| match r { |
| ty::ReErased => self.tcx.lifetimes.re_static, |
| _ => r, |
| }); |
| self.tcx().const_error(ty) |
| } |
| |
| 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 = <dyn AstConv<'tcx>>::create_substs_for_associated_item( |
| self, |
| self.tcx, |
| 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 err = struct_span_err!( |
| self.tcx().sess, |
| span, |
| E0212, |
| "cannot use the associated type of a trait \ |
| with uninferred generic parameters" |
| ); |
| |
| 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())); |
| 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)) |
| } |
| }; |
| let suggestions = vec![ |
| (lt_sp, sugg), |
| ( |
| span, |
| format!( |
| "{}::{}", |
| // Replace the existing lifetimes with a new named lifetime. |
| self.tcx |
| .replace_late_bound_regions(poly_trait_ref, |_| { |
| self.tcx.mk_region(ty::ReEarlyBound( |
| ty::EarlyBoundRegion { |
| def_id: item_def_id, |
| index: 0, |
| name: Symbol::intern(<_name), |
| }, |
| )) |
| }) |
| .0, |
| item_segment.ident |
| ), |
| ), |
| ]; |
| err.multipart_suggestion( |
| "use a fully qualified path with explicit lifetimes", |
| suggestions, |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| _ => {} |
| } |
| } |
| 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(_) => { |
| err.span_suggestion( |
| span, |
| "use a fully qualified path with inferred lifetimes", |
| format!( |
| "{}::{}", |
| // Erase named lt, we want `<A as B<'_>::C`, not `<A as B<'a>::C`. |
| self.tcx.anonymize_late_bound_regions(poly_trait_ref).skip_binder(), |
| item_segment.ident |
| ), |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| _ => {} |
| } |
| err.emit(); |
| self.tcx().ty_error() |
| } |
| } |
| |
| fn normalize_ty(&self, _span: Span, ty: Ty<'tcx>) -> Ty<'tcx> { |
| // Types in item signatures are not normalized to avoid undue dependencies. |
| ty |
| } |
| |
| fn set_tainted_by_errors(&self) { |
| // 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? |
| } |
| } |
| |
| /// 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() |
| } |
| |
| /// Returns the predicates defined on `item_def_id` of the form |
| /// `X: Foo` where `X` is the type parameter `def_id`. |
| fn type_param_predicates( |
| tcx: TyCtxt<'_>, |
| (item_def_id, def_id, assoc_name): (DefId, LocalDefId, Ident), |
| ) -> ty::GenericPredicates<'_> { |
| use rustc_hir::*; |
| |
| // In the AST, bounds can derive from two places. Either |
| // written inline like `<T: Foo>` or in a where-clause like |
| // `where T: Foo`. |
| |
| let param_id = tcx.hir().local_def_id_to_hir_id(def_id); |
| let param_owner = tcx.hir().ty_param_owner(param_id); |
| let param_owner_def_id = tcx.hir().local_def_id(param_owner); |
| let generics = tcx.generics_of(param_owner_def_id); |
| let index = generics.param_def_id_to_index[&def_id.to_def_id()]; |
| let ty = tcx.mk_ty_param(index, tcx.hir().ty_param_name(param_id)); |
| |
| // Don't look for bounds where the type parameter isn't in scope. |
| let parent = if item_def_id == param_owner_def_id.to_def_id() { |
| None |
| } else { |
| tcx.generics_of(item_def_id).parent |
| }; |
| |
| let mut result = parent |
| .map(|parent| { |
| let icx = ItemCtxt::new(tcx, parent); |
| icx.get_type_parameter_bounds(DUMMY_SP, def_id.to_def_id(), assoc_name) |
| }) |
| .unwrap_or_default(); |
| let mut extend = None; |
| |
| let item_hir_id = tcx.hir().local_def_id_to_hir_id(item_def_id.expect_local()); |
| let ast_generics = match tcx.hir().get(item_hir_id) { |
| Node::TraitItem(item) => &item.generics, |
| |
| Node::ImplItem(item) => &item.generics, |
| |
| Node::Item(item) => { |
| match item.kind { |
| ItemKind::Fn(.., ref generics, _) |
| | ItemKind::Impl(hir::Impl { ref generics, .. }) |
| | ItemKind::TyAlias(_, ref generics) |
| | ItemKind::OpaqueTy(OpaqueTy { ref generics, impl_trait_fn: None, .. }) |
| | ItemKind::Enum(_, ref generics) |
| | ItemKind::Struct(_, ref generics) |
| | ItemKind::Union(_, ref generics) => generics, |
| ItemKind::Trait(_, _, ref generics, ..) => { |
| // Implied `Self: Trait` and supertrait bounds. |
| if param_id == item_hir_id { |
| let identity_trait_ref = ty::TraitRef::identity(tcx, item_def_id); |
| extend = |
| Some((identity_trait_ref.without_const().to_predicate(tcx), item.span)); |
| } |
| generics |
| } |
| _ => return result, |
| } |
| } |
| |
| Node::ForeignItem(item) => match item.kind { |
| ForeignItemKind::Fn(_, _, ref generics) => generics, |
| _ => return result, |
| }, |
| |
| _ => return result, |
| }; |
| |
| let icx = ItemCtxt::new(tcx, item_def_id); |
| let extra_predicates = extend.into_iter().chain( |
| icx.type_parameter_bounds_in_generics( |
| ast_generics, |
| param_id, |
| ty, |
| OnlySelfBounds(true), |
| Some(assoc_name), |
| ) |
| .into_iter() |
| .filter(|(predicate, _)| match predicate.kind().skip_binder() { |
| ty::PredicateKind::Trait(data, _) => data.self_ty().is_param(index), |
| _ => false, |
| }), |
| ); |
| result.predicates = |
| tcx.arena.alloc_from_iter(result.predicates.iter().copied().chain(extra_predicates)); |
| result |
| } |
| |
| impl ItemCtxt<'tcx> { |
| /// Finds bounds from `hir::Generics`. This requires scanning through the |
| /// AST. We do this to avoid having to convert *all* the bounds, which |
| /// would create artificial cycles. Instead, we can only convert the |
| /// bounds for a type parameter `X` if `X::Foo` is used. |
| fn type_parameter_bounds_in_generics( |
| &self, |
| ast_generics: &'tcx hir::Generics<'tcx>, |
| param_id: hir::HirId, |
| ty: Ty<'tcx>, |
| only_self_bounds: OnlySelfBounds, |
| assoc_name: Option<Ident>, |
| ) -> Vec<(ty::Predicate<'tcx>, Span)> { |
| let constness = self.default_constness_for_trait_bounds(); |
| let from_ty_params = ast_generics |
| .params |
| .iter() |
| .filter_map(|param| match param.kind { |
| GenericParamKind::Type { .. } if param.hir_id == param_id => Some(¶m.bounds), |
| _ => None, |
| }) |
| .flat_map(|bounds| bounds.iter()) |
| .filter(|b| match assoc_name { |
| Some(assoc_name) => self.bound_defines_assoc_item(b, assoc_name), |
| None => true, |
| }) |
| .flat_map(|b| predicates_from_bound(self, ty, b, constness)); |
| |
| let from_where_clauses = ast_generics |
| .where_clause |
| .predicates |
| .iter() |
| .filter_map(|wp| match *wp { |
| hir::WherePredicate::BoundPredicate(ref bp) => Some(bp), |
| _ => None, |
| }) |
| .flat_map(|bp| { |
| let bt = if is_param(self.tcx, &bp.bounded_ty, param_id) { |
| Some(ty) |
| } else if !only_self_bounds.0 { |
| Some(self.to_ty(&bp.bounded_ty)) |
| } else { |
| None |
| }; |
| bp.bounds |
| .iter() |
| .filter(|b| match assoc_name { |
| Some(assoc_name) => self.bound_defines_assoc_item(b, assoc_name), |
| None => true, |
| }) |
| .filter_map(move |b| bt.map(|bt| (bt, b))) |
| }) |
| .flat_map(|(bt, b)| predicates_from_bound(self, bt, b, constness)); |
| |
| from_ty_params.chain(from_where_clauses).collect() |
| } |
| |
| fn bound_defines_assoc_item(&self, b: &hir::GenericBound<'_>, assoc_name: Ident) -> bool { |
| debug!("bound_defines_assoc_item(b={:?}, assoc_name={:?})", b, assoc_name); |
| |
| match b { |
| hir::GenericBound::Trait(poly_trait_ref, _) => { |
| let trait_ref = &poly_trait_ref.trait_ref; |
| if let Some(trait_did) = trait_ref.trait_def_id() { |
| self.tcx.trait_may_define_assoc_type(trait_did, assoc_name) |
| } else { |
| false |
| } |
| } |
| _ => false, |
| } |
| } |
| } |
| |
| /// Tests whether this is the AST for a reference to the type |
| /// parameter with ID `param_id`. We use this so as to avoid running |
| /// `ast_ty_to_ty`, because we want to avoid triggering an all-out |
| /// conversion of the type to avoid inducing unnecessary cycles. |
| fn is_param(tcx: TyCtxt<'_>, ast_ty: &hir::Ty<'_>, param_id: hir::HirId) -> bool { |
| if let hir::TyKind::Path(hir::QPath::Resolved(None, ref path)) = ast_ty.kind { |
| match path.res { |
| Res::SelfTy(Some(def_id), None) | Res::Def(DefKind::TyParam, def_id) => { |
| def_id == tcx.hir().local_def_id(param_id).to_def_id() |
| } |
| _ => false, |
| } |
| } else { |
| false |
| } |
| } |
| |
| 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.def_id; |
| |
| match it.kind { |
| // These don't define types. |
| hir::ItemKind::ExternCrate(_) |
| | hir::ItemKind::Use(..) |
| | 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.def_id); |
| tcx.ensure().type_of(item.def_id); |
| tcx.ensure().predicates_of(item.def_id); |
| match item.kind { |
| hir::ForeignItemKind::Fn(..) => tcx.ensure().fn_sig(item.def_id), |
| hir::ForeignItemKind::Static(..) => { |
| let mut visitor = PlaceholderHirTyCollector::default(); |
| visitor.visit_foreign_item(item); |
| placeholder_type_error(tcx, None, &[], visitor.0, false, None); |
| } |
| _ => (), |
| } |
| } |
| } |
| hir::ItemKind::Enum(ref enum_definition, _) => { |
| 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(), &enum_definition.variants); |
| } |
| 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).super_predicates_of(def_id); |
| tcx.ensure().predicates_of(def_id); |
| } |
| hir::ItemKind::Struct(ref struct_def, _) | hir::ItemKind::Union(ref 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() { |
| let def_id = tcx.hir().local_def_id(f.hir_id); |
| tcx.ensure().generics_of(def_id); |
| tcx.ensure().type_of(def_id); |
| tcx.ensure().predicates_of(def_id); |
| } |
| |
| if let Some(ctor_hir_id) = struct_def.ctor_hir_id() { |
| convert_variant_ctor(tcx, ctor_hir_id); |
| } |
| } |
| |
| // Desugared from `impl Trait`, so visited by the function's return type. |
| hir::ItemKind::OpaqueTy(hir::OpaqueTy { impl_trait_fn: Some(_), .. }) => {} |
| |
| // 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); |
| } |
| hir::ItemKind::TyAlias(..) |
| | hir::ItemKind::Static(..) |
| | hir::ItemKind::Const(..) |
| | hir::ItemKind::Fn(..) => { |
| tcx.ensure().generics_of(def_id); |
| tcx.ensure().type_of(def_id); |
| tcx.ensure().predicates_of(def_id); |
| match it.kind { |
| hir::ItemKind::Fn(..) => tcx.ensure().fn_sig(def_id), |
| hir::ItemKind::OpaqueTy(..) => tcx.ensure().item_bounds(def_id), |
| _ => (), |
| } |
| } |
| } |
| } |
| |
| fn convert_trait_item(tcx: TyCtxt<'_>, trait_item_id: hir::TraitItemId) { |
| let trait_item = tcx.hir().trait_item(trait_item_id); |
| tcx.ensure().generics_of(trait_item_id.def_id); |
| |
| match trait_item.kind { |
| hir::TraitItemKind::Fn(..) => { |
| tcx.ensure().type_of(trait_item_id.def_id); |
| tcx.ensure().fn_sig(trait_item_id.def_id); |
| } |
| |
| hir::TraitItemKind::Const(.., Some(_)) => { |
| tcx.ensure().type_of(trait_item_id.def_id); |
| } |
| |
| hir::TraitItemKind::Const(..) => { |
| tcx.ensure().type_of(trait_item_id.def_id); |
| // Account for `const C: _;`. |
| let mut visitor = PlaceholderHirTyCollector::default(); |
| visitor.visit_trait_item(trait_item); |
| placeholder_type_error(tcx, None, &[], visitor.0, false, None); |
| } |
| |
| hir::TraitItemKind::Type(_, Some(_)) => { |
| tcx.ensure().item_bounds(trait_item_id.def_id); |
| tcx.ensure().type_of(trait_item_id.def_id); |
| // Account for `type T = _;`. |
| let mut visitor = PlaceholderHirTyCollector::default(); |
| visitor.visit_trait_item(trait_item); |
| placeholder_type_error(tcx, None, &[], visitor.0, false, None); |
| } |
| |
| hir::TraitItemKind::Type(_, None) => { |
| tcx.ensure().item_bounds(trait_item_id.def_id); |
| // #74612: Visit and try to find bad placeholders |
| // even if there is no concrete type. |
| let mut visitor = PlaceholderHirTyCollector::default(); |
| visitor.visit_trait_item(trait_item); |
| |
| placeholder_type_error(tcx, None, &[], visitor.0, false, None); |
| } |
| }; |
| |
| tcx.ensure().predicates_of(trait_item_id.def_id); |
| } |
| |
| fn convert_impl_item(tcx: TyCtxt<'_>, impl_item_id: hir::ImplItemId) { |
| let def_id = impl_item_id.def_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().fn_sig(def_id); |
| } |
| hir::ImplItemKind::TyAlias(_) => { |
| // Account for `type T = _;` |
| let mut visitor = PlaceholderHirTyCollector::default(); |
| visitor.visit_impl_item(impl_item); |
| |
| placeholder_type_error(tcx, None, &[], visitor.0, false, None); |
| } |
| hir::ImplItemKind::Const(..) => {} |
| } |
| } |
| |
| fn convert_variant_ctor(tcx: TyCtxt<'_>, ctor_id: hir::HirId) { |
| let def_id = tcx.hir().local_def_id(ctor_id); |
| 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, variants: &[hir::Variant<'_>]) { |
| 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 variants { |
| let wrapped_discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx)); |
| prev_discr = Some( |
| if let Some(ref e) = variant.disr_expr { |
| let expr_did = tcx.hir().local_def_id(e.hir_id); |
| def.eval_explicit_discr(tcx, expr_did.to_def_id()) |
| } else if let Some(discr) = repr_type.disr_incr(tcx, prev_discr) { |
| Some(discr) |
| } else { |
| struct_span_err!(tcx.sess, variant.span, E0370, "enum discriminant overflowed") |
| .span_label( |
| variant.span, |
| format!("overflowed on value after {}", prev_discr.unwrap()), |
| ) |
| .note(&format!( |
| "explicitly set `{} = {}` if that is desired outcome", |
| variant.ident, wrapped_discr |
| )) |
| .emit(); |
| None |
| } |
| .unwrap_or(wrapped_discr), |
| ); |
| |
| for f in variant.data.fields() { |
| let def_id = tcx.hir().local_def_id(f.hir_id); |
| tcx.ensure().generics_of(def_id); |
| tcx.ensure().type_of(def_id); |
| tcx.ensure().predicates_of(def_id); |
| } |
| |
| // Convert the ctor, if any. This also registers the variant as |
| // an item. |
| if let Some(ctor_hir_id) = variant.data.ctor_hir_id() { |
| convert_variant_ctor(tcx, ctor_hir_id); |
| } |
| } |
| } |
| |
| fn convert_variant( |
| tcx: TyCtxt<'_>, |
| variant_did: Option<LocalDefId>, |
| ctor_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 fid = tcx.hir().local_def_id(f.hir_id); |
| 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: fid.to_def_id(), ident: f.ident, vis: tcx.visibility(fid) } |
| }) |
| .collect(); |
| let recovered = match def { |
| hir::VariantData::Struct(_, r) => *r, |
| _ => false, |
| }; |
| ty::VariantDef::new( |
| ident, |
| variant_did.map(LocalDefId::to_def_id), |
| ctor_did.map(LocalDefId::to_def_id), |
| discr, |
| fields, |
| CtorKind::from_hir(def), |
| adt_kind, |
| parent_did.to_def_id(), |
| recovered, |
| adt_kind == AdtKind::Struct && tcx.has_attr(parent_did.to_def_id(), sym::non_exhaustive) |
| || variant_did.map_or(false, |variant_did| { |
| tcx.has_attr(variant_did.to_def_id(), sym::non_exhaustive) |
| }), |
| ) |
| } |
| |
| fn adt_def(tcx: TyCtxt<'_>, def_id: DefId) -> &ty::AdtDef { |
| use rustc_hir::*; |
| |
| let def_id = def_id.expect_local(); |
| let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); |
| let item = match tcx.hir().get(hir_id) { |
| Node::Item(item) => item, |
| _ => bug!(), |
| }; |
| |
| let repr = ReprOptions::new(tcx, def_id.to_def_id()); |
| let (kind, variants) = match item.kind { |
| ItemKind::Enum(ref def, _) => { |
| let mut distance_from_explicit = 0; |
| let variants = def |
| .variants |
| .iter() |
| .map(|v| { |
| let variant_did = Some(tcx.hir().local_def_id(v.id)); |
| let ctor_did = |
| v.data.ctor_hir_id().map(|hir_id| tcx.hir().local_def_id(hir_id)); |
| |
| let discr = if let Some(ref e) = v.disr_expr { |
| distance_from_explicit = 0; |
| ty::VariantDiscr::Explicit(tcx.hir().local_def_id(e.hir_id).to_def_id()) |
| } else { |
| ty::VariantDiscr::Relative(distance_from_explicit) |
| }; |
| distance_from_explicit += 1; |
| |
| convert_variant( |
| tcx, |
| variant_did, |
| ctor_did, |
| v.ident, |
| discr, |
| &v.data, |
| AdtKind::Enum, |
| def_id, |
| ) |
| }) |
| .collect(); |
| |
| (AdtKind::Enum, variants) |
| } |
| ItemKind::Struct(ref def, _) => { |
| let variant_did = None::<LocalDefId>; |
| let ctor_did = def.ctor_hir_id().map(|hir_id| tcx.hir().local_def_id(hir_id)); |
| |
| let variants = std::iter::once(convert_variant( |
| tcx, |
| variant_did, |
| ctor_did, |
| item.ident, |
| ty::VariantDiscr::Relative(0), |
| def, |
| AdtKind::Struct, |
| def_id, |
| )) |
| .collect(); |
| |
| (AdtKind::Struct, variants) |
| } |
| ItemKind::Union(ref def, _) => { |
| let variant_did = None; |
| let ctor_did = def.ctor_hir_id().map(|hir_id| tcx.hir().local_def_id(hir_id)); |
| |
| let variants = std::iter::once(convert_variant( |
| tcx, |
| variant_did, |
| ctor_did, |
| item.ident, |
| ty::VariantDiscr::Relative(0), |
| def, |
| AdtKind::Union, |
| def_id, |
| )) |
| .collect(); |
| |
| (AdtKind::Union, variants) |
| } |
| _ => bug!(), |
| }; |
| tcx.alloc_adt_def(def_id.to_def_id(), kind, variants, repr) |
| } |
| |
| /// Ensures that the super-predicates of the trait with a `DefId` |
| /// of `trait_def_id` are converted and stored. This also ensures that |
| /// the transitive super-predicates are converted. |
| fn super_predicates_of(tcx: TyCtxt<'_>, trait_def_id: DefId) -> ty::GenericPredicates<'_> { |
| debug!("super_predicates(trait_def_id={:?})", trait_def_id); |
| tcx.super_predicates_that_define_assoc_type((trait_def_id, None)) |
| } |
| |
| /// Ensures that the super-predicates of the trait with a `DefId` |
| /// of `trait_def_id` are converted and stored. This also ensures that |
| /// the transitive super-predicates are converted. |
| fn super_predicates_that_define_assoc_type( |
| tcx: TyCtxt<'_>, |
| (trait_def_id, assoc_name): (DefId, Option<Ident>), |
| ) -> ty::GenericPredicates<'_> { |
| debug!( |
| "super_predicates_that_define_assoc_type(trait_def_id={:?}, assoc_name={:?})", |
| trait_def_id, assoc_name |
| ); |
| if trait_def_id.is_local() { |
| debug!("super_predicates_that_define_assoc_type: local trait_def_id={:?}", trait_def_id); |
| let trait_hir_id = tcx.hir().local_def_id_to_hir_id(trait_def_id.expect_local()); |
| |
| let item = match tcx.hir().get(trait_hir_id) { |
| Node::Item(item) => item, |
| _ => bug!("trait_node_id {} is not an item", trait_hir_id), |
| }; |
| |
| let (generics, bounds) = match item.kind { |
| hir::ItemKind::Trait(.., ref generics, ref supertraits, _) => (generics, supertraits), |
| hir::ItemKind::TraitAlias(ref generics, ref supertraits) => (generics, supertraits), |
| _ => span_bug!(item.span, "super_predicates invoked on non-trait"), |
| }; |
| |
| let icx = ItemCtxt::new(tcx, trait_def_id); |
| |
| // Convert the bounds that follow the colon, e.g., `Bar + Zed` in `trait Foo: Bar + Zed`. |
| let self_param_ty = tcx.types.self_param; |
| let superbounds1 = if let Some(assoc_name) = assoc_name { |
| <dyn AstConv<'_>>::compute_bounds_that_match_assoc_type( |
| &icx, |
| self_param_ty, |
| &bounds, |
| SizedByDefault::No, |
| item.span, |
| assoc_name, |
| ) |
| } else { |
| <dyn AstConv<'_>>::compute_bounds( |
| &icx, |
| self_param_ty, |
| &bounds, |
| SizedByDefault::No, |
| item.span, |
| ) |
| }; |
| |
| let superbounds1 = superbounds1.predicates(tcx, self_param_ty); |
| |
| // Convert any explicit superbounds in the where-clause, |
| // e.g., `trait Foo where Self: Bar`. |
| // In the case of trait aliases, however, we include all bounds in the where-clause, |
| // so e.g., `trait Foo = where u32: PartialEq<Self>` would include `u32: PartialEq<Self>` |
| // as one of its "superpredicates". |
| let is_trait_alias = tcx.is_trait_alias(trait_def_id); |
| let superbounds2 = icx.type_parameter_bounds_in_generics( |
| generics, |
| item.hir_id(), |
| self_param_ty, |
| OnlySelfBounds(!is_trait_alias), |
| assoc_name, |
| ); |
| |
| // Combine the two lists to form the complete set of superbounds: |
| let superbounds = &*tcx.arena.alloc_from_iter(superbounds1.into_iter().chain(superbounds2)); |
| |
| // Now require that immediate supertraits are converted, |
| // which will, in turn, reach indirect supertraits. |
| if assoc_name.is_none() { |
| // Now require that immediate supertraits are converted, |
| // which will, in turn, reach indirect supertraits. |
| for &(pred, span) in superbounds { |
| debug!("superbound: {:?}", pred); |
| if let ty::PredicateKind::Trait(bound, _) = pred.kind().skip_binder() { |
| tcx.at(span).super_predicates_of(bound.def_id()); |
| } |
| } |
| } |
| |
| ty::GenericPredicates { parent: None, predicates: superbounds } |
| } else { |
| // if `assoc_name` is None, then the query should've been redirected to an |
| // external provider |
| assert!(assoc_name.is_some()); |
| tcx.super_predicates_of(trait_def_id) |
| } |
| } |
| |
| fn trait_def(tcx: TyCtxt<'_>, def_id: DefId) -> ty::TraitDef { |
| let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local()); |
| let item = tcx.hir().expect_item(hir_id); |
| |
| let (is_auto, unsafety) = match item.kind { |
| hir::ItemKind::Trait(is_auto, unsafety, ..) => (is_auto == hir::IsAuto::Yes, unsafety), |
| 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 |
| .struct_span_err( |
| item.span, |
| "the `#[rustc_paren_sugar]` attribute is a temporary means of controlling \ |
| which traits can use parenthetical notation", |
| ) |
| .help("add `#![feature(unboxed_closures)]` to the crate attributes to use it") |
| .emit(); |
| } |
| |
| let is_marker = tcx.has_attr(def_id, sym::marker); |
| let spec_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 def_path_hash = tcx.def_path_hash(def_id); |
| ty::TraitDef::new(def_id, unsafety, paren_sugar, is_auto, is_marker, spec_kind, def_path_hash) |
| } |
| |
| fn has_late_bound_regions<'tcx>(tcx: TyCtxt<'tcx>, node: Node<'tcx>) -> Option<Span> { |
| struct LateBoundRegionsDetector<'tcx> { |
| tcx: TyCtxt<'tcx>, |
| outer_index: ty::DebruijnIndex, |
| has_late_bound_regions: Option<Span>, |
| } |
| |
| impl Visitor<'tcx> for LateBoundRegionsDetector<'tcx> { |
| type Map = intravisit::ErasedMap<'tcx>; |
| |
| fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> { |
| NestedVisitorMap::None |
| } |
| |
| fn visit_ty(&mut self, ty: &'tcx hir::Ty<'tcx>) { |
| if self.has_late_bound_regions.is_some() { |
| return; |
| } |
| match ty.kind { |
| hir::TyKind::BareFn(..) => { |
| self.outer_index.shift_in(1); |
| intravisit::walk_ty(self, ty); |
| self.outer_index.shift_out(1); |
| } |
| _ => intravisit::walk_ty(self, ty), |
| } |
| } |
| |
| fn visit_poly_trait_ref( |
| &mut self, |
| tr: &'tcx hir::PolyTraitRef<'tcx>, |
| m: hir::TraitBoundModifier, |
| ) { |
| if self.has_late_bound_regions.is_some() { |
| return; |
| } |
| self.outer_index.shift_in(1); |
| intravisit::walk_poly_trait_ref(self, tr, m); |
| self.outer_index.shift_out(1); |
| } |
| |
| fn visit_lifetime(&mut self, lt: &'tcx hir::Lifetime) { |
| if self.has_late_bound_regions.is_some() { |
| return; |
| } |
| |
| match self.tcx.named_region(lt.hir_id) { |
| Some(rl::Region::Static | rl::Region::EarlyBound(..)) => {} |
| Some( |
| rl::Region::LateBound(debruijn, _, _, _) |
| | rl::Region::LateBoundAnon(debruijn, _, _), |
| ) if debruijn < self.outer_index => {} |
| Some( |
| rl::Region::LateBound(..) |
| | rl::Region::LateBoundAnon(..) |
| | rl::Region::Free(..), |
| ) |
| | None => { |
| self.has_late_bound_regions = Some(lt.span); |
| } |
| } |
| } |
| } |
| |
| fn has_late_bound_regions<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| generics: &'tcx hir::Generics<'tcx>, |
| decl: &'tcx hir::FnDecl<'tcx>, |
| ) -> Option<Span> { |
| let mut visitor = LateBoundRegionsDetector { |
| tcx, |
| outer_index: ty::INNERMOST, |
| has_late_bound_regions: None, |
| }; |
| for param in generics.params { |
| if let GenericParamKind::Lifetime { .. } = param.kind { |
| if tcx.is_late_bound(param.hir_id) { |
| return Some(param.span); |
| } |
| } |
| } |
| visitor.visit_fn_decl(decl); |
| visitor.has_late_bound_regions |
| } |
| |
| match node { |
| Node::TraitItem(item) => match item.kind { |
| hir::TraitItemKind::Fn(ref sig, _) => { |
| has_late_bound_regions(tcx, &item.generics, &sig.decl) |
| } |
| _ => None, |
| }, |
| Node::ImplItem(item) => match item.kind { |
| hir::ImplItemKind::Fn(ref sig, _) => { |
| has_late_bound_regions(tcx, &item.generics, &sig.decl) |
| } |
| _ => None, |
| }, |
| Node::ForeignItem(item) => match item.kind { |
| hir::ForeignItemKind::Fn(ref fn_decl, _, ref generics) => { |
| has_late_bound_regions(tcx, generics, fn_decl) |
| } |
| _ => None, |
| }, |
| Node::Item(item) => match item.kind { |
| hir::ItemKind::Fn(ref sig, .., ref generics, _) => { |
| has_late_bound_regions(tcx, generics, &sig.decl) |
| } |
| _ => None, |
| }, |
| _ => None, |
| } |
| } |
| |
| struct AnonConstInParamListDetector { |
| in_param_list: bool, |
| found_anon_const_in_list: bool, |
| ct: HirId, |
| } |
| |
| impl<'v> Visitor<'v> for AnonConstInParamListDetector { |
| type Map = intravisit::ErasedMap<'v>; |
| |
| fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> { |
| NestedVisitorMap::None |
| } |
| |
| fn visit_generic_param(&mut self, p: &'v hir::GenericParam<'v>) { |
| let prev = self.in_param_list; |
| self.in_param_list = true; |
| intravisit::walk_generic_param(self, p); |
| self.in_param_list = prev; |
| } |
| |
| fn visit_anon_const(&mut self, c: &'v hir::AnonConst) { |
| if self.in_param_list && self.ct == c.hir_id { |
| self.found_anon_const_in_list = true; |
| } else { |
| intravisit::walk_anon_const(self, c) |
| } |
| } |
| } |
| |
| fn generics_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::Generics { |
| use rustc_hir::*; |
| |
| let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local()); |
| |
| let node = tcx.hir().get(hir_id); |
| let parent_def_id = match node { |
| Node::ImplItem(_) |
| | Node::TraitItem(_) |
| | Node::Variant(_) |
| | Node::Ctor(..) |
| | Node::Field(_) => { |
| let parent_id = tcx.hir().get_parent_item(hir_id); |
| Some(tcx.hir().local_def_id(parent_id).to_def_id()) |
| } |
| // FIXME(#43408) always enable this once `lazy_normalization` is |
| // stable enough and does not need a feature gate anymore. |
| Node::AnonConst(_) => { |
| let parent_id = tcx.hir().get_parent_item(hir_id); |
| let parent_def_id = tcx.hir().local_def_id(parent_id); |
| |
| let mut in_param_list = false; |
| for (_parent, node) in tcx.hir().parent_iter(hir_id) { |
| if let Some(generics) = node.generics() { |
| let mut visitor = AnonConstInParamListDetector { |
| in_param_list: false, |
| found_anon_const_in_list: false, |
| ct: hir_id, |
| }; |
| |
| visitor.visit_generics(generics); |
| in_param_list = visitor.found_anon_const_in_list; |
| break; |
| } |
| } |
| |
| if in_param_list { |
| // We do not allow generic parameters in anon consts if we are inside |
| // of a param list. |
| // |
| // This affects both default type bindings, e.g. `struct<T, U = [u8; std::mem::size_of::<T>()]>(T, U)`, |
| // and the types of const parameters, e.g. `struct V<const N: usize, const M: [u8; N]>();`. |
| None |
| } else if tcx.lazy_normalization() { |
| // HACK(eddyb) this provides the correct generics when |
| // `feature(const_generics)` is enabled, so that const expressions |
| // used with const generics, e.g. `Foo<{N+1}>`, can work at all. |
| // |
| // Note that we do not supply the parent generics when using |
| // `min_const_generics`. |
| Some(parent_def_id.to_def_id()) |
| } else { |
| let parent_node = tcx.hir().get(tcx.hir().get_parent_node(hir_id)); |
| match parent_node { |
| // HACK(eddyb) this provides the correct generics for repeat |
| // expressions' count (i.e. `N` in `[x; N]`), and explicit |
| // `enum` discriminants (i.e. `D` in `enum Foo { Bar = D }`), |
| // as they shouldn't be able to cause query cycle errors. |
| Node::Expr(&Expr { kind: ExprKind::Repeat(_, ref constant), .. }) |
| | Node::Variant(Variant { disr_expr: Some(ref constant), .. }) |
| if constant.hir_id == hir_id => |
| { |
| Some(parent_def_id.to_def_id()) |
| } |
| |
| _ => None, |
| } |
| } |
| } |
| Node::Expr(&hir::Expr { kind: hir::ExprKind::Closure(..), .. }) => { |
| Some(tcx.closure_base_def_id(def_id)) |
| } |
| Node::Item(item) => match item.kind { |
| ItemKind::OpaqueTy(hir::OpaqueTy { impl_trait_fn, .. }) => { |
| impl_trait_fn.or_else(|| { |
| let parent_id = tcx.hir().get_parent_item(hir_id); |
| assert!(parent_id != hir_id && parent_id != CRATE_HIR_ID); |
| debug!("generics_of: parent of opaque ty {:?} is {:?}", def_id, parent_id); |
| // Opaque types are always nested within another item, and |
| // inherit the generics of the item. |
| Some(tcx.hir().local_def_id(parent_id).to_def_id()) |
| }) |
| } |
| _ => None, |
| }, |
| _ => None, |
| }; |
| |
| let mut opt_self = None; |
| let mut allow_defaults = false; |
| |
| let no_generics = hir::Generics::empty(); |
| let ast_generics = match node { |
| Node::TraitItem(item) => &item.generics, |
| |
| Node::ImplItem(item) => &item.generics, |
| |
| Node::Item(item) => { |
| match item.kind { |
| ItemKind::Fn(.., ref generics, _) |
| | ItemKind::Impl(hir::Impl { ref generics, .. }) => generics, |
| |
| ItemKind::TyAlias(_, ref generics) |
| | ItemKind::Enum(_, ref generics) |
| | ItemKind::Struct(_, ref generics) |
| | ItemKind::OpaqueTy(hir::OpaqueTy { ref generics, .. }) |
| | ItemKind::Union(_, ref generics) => { |
| allow_defaults = true; |
| generics |
| } |
| |
| ItemKind::Trait(_, _, ref generics, ..) |
| | ItemKind::TraitAlias(ref generics, ..) => { |
| // Add in the self type parameter. |
| // |
| // Something of a hack: use the node id for the trait, also as |
| // the node id for the Self type parameter. |
| let param_id = item.def_id; |
| |
| opt_self = Some(ty::GenericParamDef { |
| index: 0, |
| name: kw::SelfUpper, |
| def_id: param_id.to_def_id(), |
| pure_wrt_drop: false, |
| kind: ty::GenericParamDefKind::Type { |
| has_default: false, |
| object_lifetime_default: rl::Set1::Empty, |
| synthetic: None, |
| }, |
| }); |
| |
| allow_defaults = true; |
| generics |
| } |
| |
| _ => &no_generics, |
| } |
| } |
| |
| Node::ForeignItem(item) => match item.kind { |
| ForeignItemKind::Static(..) => &no_generics, |
| ForeignItemKind::Fn(_, _, ref generics) => generics, |
| ForeignItemKind::Type => &no_generics, |
| }, |
| |
| _ => &no_generics, |
| }; |
| |
| let has_self = opt_self.is_some(); |
| let mut parent_has_self = false; |
| let mut own_start = has_self as u32; |
| let parent_count = parent_def_id.map_or(0, |def_id| { |
| let generics = tcx.generics_of(def_id); |
| assert_eq!(has_self, false); |
| parent_has_self = generics.has_self; |
| own_start = generics.count() as u32; |
| generics.parent_count + generics.params.len() |
| }); |
| |
| let mut params: Vec<_> = Vec::with_capacity(ast_generics.params.len() + has_self as usize); |
| |
| if let Some(opt_self) = opt_self { |
| params.push(opt_self); |
| } |
| |
| let early_lifetimes = early_bound_lifetimes_from_generics(tcx, ast_generics); |
| params.extend(early_lifetimes.enumerate().map(|(i, param)| ty::GenericParamDef { |
| name: param.name.ident().name, |
| index: own_start + i as u32, |
| def_id: tcx.hir().local_def_id(param.hir_id).to_def_id(), |
| pure_wrt_drop: param.pure_wrt_drop, |
| kind: ty::GenericParamDefKind::Lifetime, |
| })); |
| |
| let object_lifetime_defaults = tcx.object_lifetime_defaults(hir_id); |
| |
| // Now create the real type and const parameters. |
| let type_start = own_start - has_self as u32 + params.len() as u32; |
| let mut i = 0; |
| |
| params.extend(ast_generics.params.iter().filter_map(|param| match param.kind { |
| GenericParamKind::Lifetime { .. } => None, |
| GenericParamKind::Type { ref default, synthetic, .. } => { |
| if !allow_defaults && default.is_some() { |
| if !tcx.features().default_type_parameter_fallback { |
| tcx.struct_span_lint_hir( |
| lint::builtin::INVALID_TYPE_PARAM_DEFAULT, |
| param.hir_id, |
| param.span, |
| |lint| { |
| lint.build( |
| "defaults for type parameters are only allowed in \ |
| `struct`, `enum`, `type`, or `trait` definitions", |
| ) |
| .emit(); |
| }, |
| ); |
| } |
| } |
| |
| let kind = ty::GenericParamDefKind::Type { |
| has_default: default.is_some(), |
| object_lifetime_default: object_lifetime_defaults |
| .as_ref() |
| .map_or(rl::Set1::Empty, |o| o[i]), |
| synthetic, |
| }; |
| |
| let param_def = ty::GenericParamDef { |
| index: type_start + i as u32, |
| name: param.name.ident().name, |
| def_id: tcx.hir().local_def_id(param.hir_id).to_def_id(), |
| pure_wrt_drop: param.pure_wrt_drop, |
| kind, |
| }; |
| i += 1; |
| Some(param_def) |
| } |
| GenericParamKind::Const { default, .. } => { |
| if !allow_defaults && default.is_some() { |
| tcx.sess.span_err( |
| param.span, |
| "defaults for const parameters are only allowed in \ |
| `struct`, `enum`, `type`, or `trait` definitions", |
| ); |
| } |
| |
| let param_def = ty::GenericParamDef { |
| index: type_start + i as u32, |
| name: param.name.ident().name, |
| def_id: tcx.hir().local_def_id(param.hir_id).to_def_id(), |
| pure_wrt_drop: param.pure_wrt_drop, |
| kind: ty::GenericParamDefKind::Const { has_default: default.is_some() }, |
| }; |
| i += 1; |
| Some(param_def) |
| } |
| })); |
| |
| // provide junk type parameter defs - the only place that |
| // cares about anything but the length is instantiation, |
| // and we don't do that for closures. |
| if let Node::Expr(&hir::Expr { kind: hir::ExprKind::Closure(.., gen), .. }) = node { |
| let dummy_args = if gen.is_some() { |
| &["<resume_ty>", "<yield_ty>", "<return_ty>", "<witness>", "<upvars>"][..] |
| } else { |
| &["<closure_kind>", "<closure_signature>", "<upvars>"][..] |
| }; |
| |
| params.extend(dummy_args.iter().enumerate().map(|(i, &arg)| ty::GenericParamDef { |
| index: type_start + i as u32, |
| name: Symbol::intern(arg), |
| def_id, |
| pure_wrt_drop: false, |
| kind: ty::GenericParamDefKind::Type { |
| has_default: false, |
| object_lifetime_default: rl::Set1::Empty, |
| synthetic: None, |
| }, |
| })); |
| } |
| |
| let param_def_id_to_index = params.iter().map(|param| (param.def_id, param.index)).collect(); |
| |
| ty::Generics { |
| parent: parent_def_id, |
| parent_count, |
| params, |
| param_def_id_to_index, |
| has_self: has_self || parent_has_self, |
| has_late_bound_regions: has_late_bound_regions(tcx, node), |
| } |
| } |
| |
| fn are_suggestable_generic_args(generic_args: &[hir::GenericArg<'_>]) -> bool { |
| generic_args |
| .iter() |
| .filter_map(|arg| match arg { |
| hir::GenericArg::Type(ty) => Some(ty), |
| _ => None, |
| }) |
| .any(is_suggestable_infer_ty) |
| } |
| |
| /// 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 { |
| use hir::TyKind::*; |
| match &ty.kind { |
| Infer => true, |
| Slice(ty) | Array(ty, _) => is_suggestable_infer_ty(ty), |
| Tup(tys) => tys.iter().any(is_suggestable_infer_ty), |
| Ptr(mut_ty) | Rptr(_, 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.map_or(false, is_suggestable_infer_ty) |
| || segments.iter().any(|segment| are_suggestable_generic_args(segment.args().args)) |
| } |
| _ => false, |
| } |
| } |
| |
| pub fn get_infer_ret_ty(output: &'hir hir::FnRetTy<'hir>) -> Option<&'hir hir::Ty<'hir>> { |
| if let hir::FnRetTy::Return(ref ty) = output { |
| if is_suggestable_infer_ty(ty) { |
| return Some(&**ty); |
| } |
| } |
| None |
| } |
| |
| fn fn_sig(tcx: TyCtxt<'_>, def_id: DefId) -> ty::PolyFnSig<'_> { |
| use rustc_hir::Node::*; |
| use rustc_hir::*; |
| |
| let def_id = def_id.expect_local(); |
| let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); |
| |
| let icx = ItemCtxt::new(tcx, def_id.to_def_id()); |
| |
| match tcx.hir().get(hir_id) { |
| TraitItem(hir::TraitItem { |
| kind: TraitItemKind::Fn(sig, TraitFn::Provided(_)), |
| ident, |
| generics, |
| .. |
| }) |
| | ImplItem(hir::ImplItem { kind: ImplItemKind::Fn(sig, _), ident, generics, .. }) |
| | Item(hir::Item { kind: ItemKind::Fn(sig, generics, _), ident, .. }) => { |
| 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, &mut false, |r, _| match r { |
| ty::ReErased => tcx.lifetimes.re_static, |
| _ => r, |
| }); |
| |
| let mut visitor = PlaceholderHirTyCollector::default(); |
| visitor.visit_ty(ty); |
| let mut diag = bad_placeholder_type(tcx, visitor.0); |
| let ret_ty = fn_sig.output(); |
| if ret_ty != tcx.ty_error() { |
| if !ret_ty.is_closure() { |
| let ret_ty_str = match ret_ty.kind() { |
| // Suggest a function pointer return type instead of a unique function definition |
| // (e.g. `fn() -> i32` instead of `fn() -> i32 { f }`, the latter of which is invalid |
| // syntax) |
| ty::FnDef(..) => ret_ty.fn_sig(tcx).to_string(), |
| _ => ret_ty.to_string(), |
| }; |
| diag.span_suggestion( |
| ty.span, |
| "replace with the correct return type", |
| ret_ty_str, |
| Applicability::MaybeIncorrect, |
| ); |
| } else { |
| // We're dealing with a closure, so we should suggest using `impl Fn` or trait bounds |
| // to prevent the user from getting a papercut while trying to use the unique closure |
| // syntax (e.g. `[closure@src/lib.rs:2:5: 2:9]`). |
| diag.help("consider using an `Fn`, `FnMut`, or `FnOnce` trait bound"); |
| diag.note("for more information on `Fn` traits and closure types, see https://doc.rust-lang.org/book/ch13-01-closures.html"); |
| } |
| } |
| diag.emit(); |
| |
| ty::Binder::bind(fn_sig, tcx) |
| } |
| None => <dyn AstConv<'_>>::ty_of_fn( |
| &icx, |
| hir_id, |
| sig.header.unsafety, |
| sig.header.abi, |
| &sig.decl, |
| &generics, |
| Some(ident.span), |
| None, |
| ), |
| } |
| } |
| |
| TraitItem(hir::TraitItem { |
| kind: TraitItemKind::Fn(FnSig { header, decl, span: _ }, _), |
| ident, |
| generics, |
| .. |
| }) => <dyn AstConv<'_>>::ty_of_fn( |
| &icx, |
| hir_id, |
| header.unsafety, |
| header.abi, |
| decl, |
| &generics, |
| Some(ident.span), |
| None, |
| ), |
| |
| ForeignItem(&hir::ForeignItem { |
| kind: ForeignItemKind::Fn(ref fn_decl, _, _), |
| ident, |
| .. |
| }) => { |
| let abi = tcx.hir().get_foreign_abi(hir_id); |
| compute_sig_of_foreign_fn_decl(tcx, def_id.to_def_id(), fn_decl, abi, ident) |
| } |
| |
| Ctor(data) | Variant(hir::Variant { data, .. }) if data.ctor_hir_id().is_some() => { |
| let ty = tcx.type_of(tcx.hir().get_parent_did(hir_id).to_def_id()); |
| let inputs = |
| data.fields().iter().map(|f| tcx.type_of(tcx.hir().local_def_id(f.hir_id))); |
| ty::Binder::bind( |
| tcx.mk_fn_sig(inputs, ty, false, hir::Unsafety::Normal, abi::Abi::Rust), |
| tcx, |
| ) |
| } |
| |
| 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); |
| } |
| } |
| } |
| |
| fn impl_trait_ref(tcx: TyCtxt<'_>, def_id: DefId) -> Option<ty::TraitRef<'_>> { |
| let icx = ItemCtxt::new(tcx, def_id); |
| |
| let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local()); |
| match tcx.hir().expect_item(hir_id).kind { |
| hir::ItemKind::Impl(ref impl_) => impl_.of_trait.as_ref().map(|ast_trait_ref| { |
| let selfty = tcx.type_of(def_id); |
| <dyn AstConv<'_>>::instantiate_mono_trait_ref(&icx, ast_trait_ref, selfty) |
| }), |
| _ => bug!(), |
| } |
| } |
| |
| fn impl_polarity(tcx: TyCtxt<'_>, def_id: DefId) -> ty::ImplPolarity { |
| let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local()); |
| let is_rustc_reservation = tcx.has_attr(def_id, sym::rustc_reservation_impl); |
| let item = tcx.hir().expect_item(hir_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. |
| fn predicates_defined_on(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicates<'_> { |
| debug!("predicates_defined_on({:?})", def_id); |
| 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, |
| ); |
| if result.predicates.is_empty() { |
| result.predicates = inferred_outlives; |
| } else { |
| result.predicates = tcx |
| .arena |
| .alloc_from_iter(result.predicates.iter().chain(inferred_outlives).copied()); |
| } |
| } |
| |
| debug!("predicates_defined_on({:?}) = {:?}", def_id, result); |
| result |
| } |
| |
| /// Returns a list of all type predicates (explicit and implicit) for the definition with |
| /// ID `def_id`. This includes all predicates returned by `predicates_defined_on`, plus |
| /// `Self: Trait` predicates for traits. |
| fn predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicates<'_> { |
| let mut result = tcx.predicates_defined_on(def_id); |
| |
| if tcx.is_trait(def_id) { |
| // For traits, add `Self: Trait` predicate. This is |
| // not part of the predicates that a user writes, but it |
| // is something that one must prove in order to invoke a |
| // method or project an associated type. |
| // |
| // In the chalk setup, this predicate is not part of the |
| // "predicates" for a trait item. But it is useful in |
| // rustc because if you directly (e.g.) invoke a trait |
| // method like `Trait::method(...)`, you must naturally |
| // prove that the trait applies to the types that were |
| // used, and adding the predicate into this list ensures |
| // that this is done. |
| let span = tcx.sess.source_map().guess_head_span(tcx.def_span(def_id)); |
| result.predicates = |
| tcx.arena.alloc_from_iter(result.predicates.iter().copied().chain(std::iter::once(( |
| ty::TraitRef::identity(tcx, def_id).without_const().to_predicate(tcx), |
| span, |
| )))); |
| } |
| debug!("predicates_of(def_id={:?}) = {:?}", def_id, result); |
| result |
| } |
| |
| /// Returns a list of user-specified type predicates for the definition with ID `def_id`. |
| /// N.B., this does not include any implied/inferred constraints. |
| fn gather_explicit_predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicates<'_> { |
| use rustc_hir::*; |
| |
| debug!("explicit_predicates_of(def_id={:?})", def_id); |
| |
| let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local()); |
| let node = tcx.hir().get(hir_id); |
| |
| let mut is_trait = None; |
| let mut is_default_impl_trait = None; |
| |
| let icx = ItemCtxt::new(tcx, def_id); |
| let constness = icx.default_constness_for_trait_bounds(); |
| |
| const NO_GENERICS: &hir::Generics<'_> = &hir::Generics::empty(); |
| |
| // We use an `IndexSet` to preserves order of insertion. |
| // Preserving the order of insertion is important here so as not to break UI tests. |
| let mut predicates: FxIndexSet<(ty::Predicate<'_>, Span)> = FxIndexSet::default(); |
| |
| let ast_generics = match node { |
| Node::TraitItem(item) => &item.generics, |
| |
| Node::ImplItem(item) => &item.generics, |
| |
| Node::Item(item) => { |
| match item.kind { |
| ItemKind::Impl(ref impl_) => { |
| if impl_.defaultness.is_default() { |
| is_default_impl_trait = tcx.impl_trait_ref(def_id); |
| } |
| &impl_.generics |
| } |
| ItemKind::Fn(.., ref generics, _) |
| | ItemKind::TyAlias(_, ref generics) |
| | ItemKind::Enum(_, ref generics) |
| | ItemKind::Struct(_, ref generics) |
| | ItemKind::Union(_, ref generics) => generics, |
| |
| ItemKind::Trait(_, _, ref generics, ..) => { |
| is_trait = Some(ty::TraitRef::identity(tcx, def_id)); |
| generics |
| } |
| ItemKind::TraitAlias(ref generics, _) => { |
| is_trait = Some(ty::TraitRef::identity(tcx, def_id)); |
| generics |
| } |
| ItemKind::OpaqueTy(OpaqueTy { |
| bounds: _, |
| impl_trait_fn, |
| ref generics, |
| origin: _, |
| }) => { |
| if impl_trait_fn.is_some() { |
| // return-position impl trait |
| // |
| // We don't inherit predicates from the parent here: |
| // If we have, say `fn f<'a, T: 'a>() -> impl Sized {}` |
| // then the return type is `f::<'static, T>::{{opaque}}`. |
| // |
| // If we inherited the predicates of `f` then we would |
| // require that `T: 'static` to show that the return |
| // type is well-formed. |
| // |
| // The only way to have something with this opaque type |
| // is from the return type of the containing function, |
| // which will ensure that the function's predicates |
| // hold. |
| return ty::GenericPredicates { parent: None, predicates: &[] }; |
| } else { |
| // type-alias impl trait |
| generics |
| } |
| } |
| |
| _ => NO_GENERICS, |
| } |
| } |
| |
| Node::ForeignItem(item) => match item.kind { |
| ForeignItemKind::Static(..) => NO_GENERICS, |
| ForeignItemKind::Fn(_, _, ref generics) => generics, |
| ForeignItemKind::Type => NO_GENERICS, |
| }, |
| |
| _ => NO_GENERICS, |
| }; |
| |
| let generics = tcx.generics_of(def_id); |
| let parent_count = generics.parent_count as u32; |
| let has_own_self = generics.has_self && parent_count == 0; |
| |
| // Below we'll consider the bounds on the type parameters (including `Self`) |
| // and the explicit where-clauses, but to get the full set of predicates |
| // on a trait we need to add in the supertrait bounds and bounds found on |
| // associated types. |
| if let Some(_trait_ref) = is_trait { |
| predicates.extend(tcx.super_predicates_of(def_id).predicates.iter().cloned()); |
| } |
| |
| // In default impls, we can assume that the self type implements |
| // the trait. So in: |
| // |
| // default impl Foo for Bar { .. } |
| // |
| // we add a default where clause `Foo: Bar`. We do a similar thing for traits |
| // (see below). Recall that a default impl is not itself an impl, but rather a |
| // set of defaults that can be incorporated into another impl. |
| if let Some(trait_ref) = is_default_impl_trait { |
| predicates.insert(( |
| trait_ref.to_poly_trait_ref().without_const().to_predicate(tcx), |
| tcx.def_span(def_id), |
| )); |
| } |
| |
| // Collect the region predicates that were declared inline as |
| // well. In the case of parameters declared on a fn or method, we |
| // have to be careful to only iterate over early-bound regions. |
| let mut index = parent_count + has_own_self as u32; |
| for param in early_bound_lifetimes_from_generics(tcx, ast_generics) { |
| let region = tcx.mk_region(ty::ReEarlyBound(ty::EarlyBoundRegion { |
| def_id: tcx.hir().local_def_id(param.hir_id).to_def_id(), |
| index, |
| name: param.name.ident().name, |
| })); |
| index += 1; |
| |
| match param.kind { |
| GenericParamKind::Lifetime { .. } => { |
| param.bounds.iter().for_each(|bound| match bound { |
| hir::GenericBound::Outlives(lt) => { |
| let bound = <dyn AstConv<'_>>::ast_region_to_region(&icx, <, None); |
| let outlives = ty::Binder::bind(ty::OutlivesPredicate(region, bound), tcx); |
| predicates.insert((outlives.to_predicate(tcx), lt.span)); |
| } |
| _ => bug!(), |
| }); |
| } |
| _ => bug!(), |
| } |
| } |
| |
| // Collect the predicates that were written inline by the user on each |
| // type parameter (e.g., `<T: Foo>`). |
| for param in ast_generics.params { |
| match param.kind { |
| // We already dealt with early bound lifetimes above. |
| GenericParamKind::Lifetime { .. } => (), |
| GenericParamKind::Type { .. } => { |
| let name = param.name.ident().name; |
| let param_ty = ty::ParamTy::new(index, name).to_ty(tcx); |
| index += 1; |
| |
| let sized = SizedByDefault::Yes; |
| let bounds = <dyn AstConv<'_>>::compute_bounds( |
| &icx, |
| param_ty, |
| ¶m.bounds, |
| sized, |
| param.span, |
| ); |
| predicates.extend(bounds.predicates(tcx, param_ty)); |
| } |
| GenericParamKind::Const { .. } => { |
| // Bounds on const parameters are currently not possible. |
| debug_assert!(param.bounds.is_empty()); |
| index += 1; |
| } |
| } |
| } |
| |
| // Add in the bounds that appear in the where-clause. |
| let where_clause = &ast_generics.where_clause; |
| for predicate in where_clause.predicates { |
| match predicate { |
| hir::WherePredicate::BoundPredicate(bound_pred) => { |
| let ty = icx.to_ty(&bound_pred.bounded_ty); |
| let bound_vars = icx.tcx.late_bound_vars(bound_pred.bounded_ty.hir_id); |
| |
| // Keep the type around in a dummy predicate, in case of no bounds. |
| // That way, `where Ty:` is not a complete noop (see #53696) and `Ty` |
| // is still checked for WF. |
| if bound_pred.bounds.is_empty() { |
| if let ty::Param(_) = ty.kind() { |
| // This is a `where T:`, which can be in the HIR from the |
| // transformation that moves `?Sized` to `T`'s declaration. |
| // We can skip the predicate because type parameters are |
| // trivially WF, but also we *should*, to avoid exposing |
| // users who never wrote `where Type:,` themselves, to |
| // compiler/tooling bugs from not handling WF predicates. |
| } else { |
| let span = bound_pred.bounded_ty.span; |
| let re_root_empty = tcx.lifetimes.re_root_empty; |
| let predicate = ty::Binder::bind_with_vars( |
| ty::PredicateKind::TypeOutlives(ty::OutlivesPredicate( |
| ty, |
| re_root_empty, |
| )), |
| bound_vars, |
| ); |
| predicates.insert((predicate.to_predicate(tcx), span)); |
| } |
| } |
| |
| for bound in bound_pred.bounds.iter() { |
| match bound { |
| hir::GenericBound::Trait(poly_trait_ref, modifier) => { |
| let constness = match modifier { |
| hir::TraitBoundModifier::MaybeConst => hir::Constness::NotConst, |
| hir::TraitBoundModifier::None => constness, |
| hir::TraitBoundModifier::Maybe => bug!("this wasn't handled"), |
| }; |
| |
| let mut bounds = Bounds::default(); |
| let _ = <dyn AstConv<'_>>::instantiate_poly_trait_ref( |
| &icx, |
| &poly_trait_ref.trait_ref, |
| poly_trait_ref.span, |
| constness, |
| ty, |
| &mut bounds, |
| false, |
| ); |
| predicates.extend(bounds.predicates(tcx, ty)); |
| } |
| |
| &hir::GenericBound::LangItemTrait(lang_item, span, hir_id, args) => { |
| let mut bounds = Bounds::default(); |
| <dyn AstConv<'_>>::instantiate_lang_item_trait_ref( |
| &icx, |
| lang_item, |
| span, |
| hir_id, |
| args, |
| ty, |
| &mut bounds, |
| ); |
| predicates.extend(bounds.predicates(tcx, ty)); |
| } |
| |
| hir::GenericBound::Outlives(lifetime) => { |
| let region = |
| <dyn AstConv<'_>>::ast_region_to_region(&icx, lifetime, None); |
| predicates.insert(( |
| ty::Binder::bind_with_vars( |
| ty::PredicateKind::TypeOutlives(ty::OutlivesPredicate( |
| ty, region, |
| )), |
| bound_vars, |
| ) |
| .to_predicate(tcx), |
| lifetime.span, |
| )); |
| } |
| } |
| } |
| } |
| |
| hir::WherePredicate::RegionPredicate(region_pred) => { |
| let r1 = <dyn AstConv<'_>>::ast_region_to_region(&icx, ®ion_pred.lifetime, None); |
| predicates.extend(region_pred.bounds.iter().map(|bound| { |
| let (r2, span) = match bound { |
| hir::GenericBound::Outlives(lt) => { |
| (<dyn AstConv<'_>>::ast_region_to_region(&icx, lt, None), lt.span) |
| } |
| _ => bug!(), |
| }; |
| let pred = ty::PredicateKind::RegionOutlives(ty::OutlivesPredicate(r1, r2)) |
| .to_predicate(icx.tcx); |
| |
| (pred, span) |
| })) |
| } |
| |
| hir::WherePredicate::EqPredicate(..) => { |
| // FIXME(#20041) |
| } |
| } |
| } |
| |
| if tcx.features().const_evaluatable_checked { |
| predicates.extend(const_evaluatable_predicates_of(tcx, def_id.expect_local())); |
| } |
| |
| let mut predicates: Vec<_> = predicates.into_iter().collect(); |
| |
| // Subtle: before we store the predicates into the tcx, we |
| // sort them so that predicates like `T: Foo<Item=U>` come |
| // before uses of `U`. This avoids false ambiguity errors |
| // in trait checking. See `setup_constraining_predicates` |
| // for details. |
| if let Node::Item(&Item { kind: ItemKind::Impl { .. }, .. }) = node { |
| let self_ty = tcx.type_of(def_id); |
| let trait_ref = tcx.impl_trait_ref(def_id); |
| cgp::setup_constraining_predicates( |
| tcx, |
| &mut predicates, |
| trait_ref, |
| &mut cgp::parameters_for_impl(self_ty, trait_ref), |
| ); |
| } |
| |
| let result = ty::GenericPredicates { |
| parent: generics.parent, |
| predicates: tcx.arena.alloc_from_iter(predicates), |
| }; |
| debug!("explicit_predicates_of(def_id={:?}) = {:?}", def_id, result); |
| result |
| } |
| |
| fn const_evaluatable_predicates_of<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| def_id: LocalDefId, |
| ) -> FxIndexSet<(ty::Predicate<'tcx>, Span)> { |
| struct ConstCollector<'tcx> { |
| tcx: TyCtxt<'tcx>, |
| preds: FxIndexSet<(ty::Predicate<'tcx>, Span)>, |
| } |
| |
| impl<'tcx> intravisit::Visitor<'tcx> for ConstCollector<'tcx> { |
| type Map = Map<'tcx>; |
| |
| fn nested_visit_map(&mut self) -> intravisit::NestedVisitorMap<Self::Map> { |
| intravisit::NestedVisitorMap::None |
| } |
| |
| fn visit_anon_const(&mut self, c: &'tcx hir::AnonConst) { |
| let def_id = self.tcx.hir().local_def_id(c.hir_id); |
| let ct = ty::Const::from_anon_const(self.tcx, def_id); |
| if let ty::ConstKind::Unevaluated(uv) = ct.val { |
| assert_eq!(uv.promoted, None); |
| let span = self.tcx.hir().span(c.hir_id); |
| self.preds.insert(( |
| ty::PredicateKind::ConstEvaluatable(uv.def, uv.substs).to_predicate(self.tcx), |
| span, |
| )); |
| } |
| } |
| } |
| |
| let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); |
| let node = tcx.hir().get(hir_id); |
| |
| let mut collector = ConstCollector { tcx, preds: FxIndexSet::default() }; |
| if let hir::Node::Item(item) = node { |
| if let hir::ItemKind::Impl(ref impl_) = item.kind { |
| if let Some(of_trait) = &impl_.of_trait { |
| debug!("const_evaluatable_predicates_of({:?}): visit impl trait_ref", def_id); |
| collector.visit_trait_ref(of_trait); |
| } |
| |
| debug!("const_evaluatable_predicates_of({:?}): visit_self_ty", def_id); |
| collector.visit_ty(impl_.self_ty); |
| } |
| } |
| |
| if let Some(generics) = node.generics() { |
| debug!("const_evaluatable_predicates_of({:?}): visit_generics", def_id); |
| collector.visit_generics(generics); |
| } |
| |
| if let Some(fn_sig) = tcx.hir().fn_sig_by_hir_id(hir_id) { |
| debug!("const_evaluatable_predicates_of({:?}): visit_fn_decl", def_id); |
| collector.visit_fn_decl(fn_sig.decl); |
| } |
| debug!("const_evaluatable_predicates_of({:?}) = {:?}", def_id, collector.preds); |
| |
| collector.preds |
| } |
| |
| fn trait_explicit_predicates_and_bounds( |
| tcx: TyCtxt<'_>, |
| def_id: LocalDefId, |
| ) -> ty::GenericPredicates<'_> { |
| assert_eq!(tcx.def_kind(def_id), DefKind::Trait); |
| gather_explicit_predicates_of(tcx, def_id.to_def_id()) |
| } |
| |
| fn explicit_predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicates<'_> { |
| if let DefKind::Trait = tcx.def_kind(def_id) { |
| // Remove bounds on associated types from the predicates, they will be |
| // returned by `explicit_item_bounds`. |
| let predicates_and_bounds = tcx.trait_explicit_predicates_and_bounds(def_id.expect_local()); |
| let trait_identity_substs = InternalSubsts::identity_for_item(tcx, def_id); |
| |
| let is_assoc_item_ty = |ty: Ty<'_>| { |
| // For a predicate from a where clause to become a bound on an |
| // associated type: |
| // * It must use the identity substs of the item. |
| // * Since any generic parameters on the item are not in scope, |
| // this means that the item is not a GAT, and its identity |
| // substs are the same as the trait's. |
| // * It must be an associated type for this trait (*not* a |
| // supertrait). |
| if let ty::Projection(projection) = ty.kind() { |
| projection.substs == trait_identity_substs |
| && tcx.associated_item(projection.item_def_id).container.id() == def_id |
| } else { |
| false |
| } |
| }; |
| |
| let predicates: Vec<_> = predicates_and_bounds |
| .predicates |
| .iter() |
| .copied() |
| .filter(|(pred, _)| match pred.kind().skip_binder() { |
| ty::PredicateKind::Trait(tr, _) => !is_assoc_item_ty(tr.self_ty()), |
| ty::PredicateKind::Projection(proj) => { |
| !is_assoc_item_ty(proj.projection_ty.self_ty()) |
| } |
| ty::PredicateKind::TypeOutlives(outlives) => !is_assoc_item_ty(outlives.0), |
| _ => true, |
| }) |
| .collect(); |
| if predicates.len() == predicates_and_bounds.predicates.len() { |
| predicates_and_bounds |
| } else { |
| ty::GenericPredicates { |
| parent: predicates_and_bounds.parent, |
| predicates: tcx.arena.alloc_slice(&predicates), |
| } |
| } |
| } else { |
| gather_explicit_predicates_of(tcx, def_id) |
| } |
| } |
| |
| fn projection_ty_from_predicates( |
| tcx: TyCtxt<'tcx>, |
| key: ( |
| // ty_def_id |
| DefId, |
| // def_id of `N` in `<T as Trait>::N` |
| DefId, |
| ), |
| ) -> Option<ty::ProjectionTy<'tcx>> { |
| let (ty_def_id, item_def_id) = key; |
| let mut projection_ty = None; |
| for (predicate, _) in tcx.predicates_of(ty_def_id).predicates { |
| if let ty::PredicateKind::Projection(projection_predicate) = predicate.kind().skip_binder() |
| { |
| if item_def_id == projection_predicate.projection_ty.item_def_id { |
| projection_ty = Some(projection_predicate.projection_ty); |
| break; |
| } |
| } |
| } |
| projection_ty |
| } |
| |
| /// Converts a specific `GenericBound` from the AST into a set of |
| /// predicates that apply to the self type. A vector is returned |
| /// because this can be anywhere from zero predicates (`T: ?Sized` adds no |
| /// predicates) to one (`T: Foo`) to many (`T: Bar<X = i32>` adds `T: Bar` |
| /// and `<T as Bar>::X == i32`). |
| fn predicates_from_bound<'tcx>( |
| astconv: &dyn AstConv<'tcx>, |
| param_ty: Ty<'tcx>, |
| bound: &'tcx hir::GenericBound<'tcx>, |
| constness: hir::Constness, |
| ) -> Vec<(ty::Predicate<'tcx>, Span)> { |
| match *bound { |
| hir::GenericBound::Trait(ref tr, modifier) => { |
| let constness = match modifier { |
| hir::TraitBoundModifier::Maybe => return vec![], |
| hir::TraitBoundModifier::MaybeConst => hir::Constness::NotConst, |
| hir::TraitBoundModifier::None => constness, |
| }; |
| |
| let mut bounds = Bounds::default(); |
| let _ = astconv.instantiate_poly_trait_ref( |
| &tr.trait_ref, |
| tr.span, |
| constness, |
| param_ty, |
| &mut bounds, |
| false, |
| ); |
| bounds.predicates(astconv.tcx(), param_ty) |
| } |
| hir::GenericBound::LangItemTrait(lang_item, span, hir_id, args) => { |
| let mut bounds = Bounds::default(); |
| astconv.instantiate_lang_item_trait_ref( |
| lang_item, |
| span, |
| hir_id, |
| args, |
| param_ty, |
| &mut bounds, |
| ); |
| bounds.predicates(astconv.tcx(), param_ty) |
| } |
| hir::GenericBound::Outlives(ref lifetime) => { |
| let region = astconv.ast_region_to_region(lifetime, None); |
| let pred = ty::PredicateKind::TypeOutlives(ty::OutlivesPredicate(param_ty, region)) |
| .to_predicate(astconv.tcx()); |
| vec![(pred, lifetime.span)] |
| } |
| } |
| } |
| |
| fn compute_sig_of_foreign_fn_decl<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| def_id: DefId, |
| decl: &'tcx hir::FnDecl<'tcx>, |
| abi: abi::Abi, |
| ident: Ident, |
| ) -> ty::PolyFnSig<'tcx> { |
| let unsafety = if abi == abi::Abi::RustIntrinsic { |
| intrinsic_operation_unsafety(tcx.item_name(def_id)) |
| } else { |
| hir::Unsafety::Unsafe |
| }; |
| let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local()); |
| let fty = <dyn AstConv<'_>>::ty_of_fn( |
| &ItemCtxt::new(tcx, def_id), |
| hir_id, |
| unsafety, |
| abi, |
| decl, |
| &hir::Generics::empty(), |
| Some(ident.span), |
| 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 |
| .struct_span_err( |
| ast_ty.span, |
| &format!( |
| "use of SIMD type{} in FFI is highly experimental and \ |
| may result in invalid code", |
| snip |
| ), |
| ) |
| .help("add `#![feature(simd_ffi)]` to the crate attributes to enable") |
| .emit(); |
| } |
| }; |
| for (input, ty) in iter::zip(decl.inputs, fty.inputs().skip_binder()) { |
| check(&input, ty) |
| } |
| if let hir::FnRetTy::Return(ref ty) = decl.output { |
| check(&ty, fty.output().skip_binder()) |
| } |
| } |
| |
| fty |
| } |
| |
| fn is_foreign_item(tcx: TyCtxt<'_>, def_id: DefId) -> bool { |
| match tcx.hir().get_if_local(def_id) { |
| Some(Node::ForeignItem(..)) => true, |
| Some(_) => false, |
| _ => bug!("is_foreign_item applied to non-local def-id {:?}", def_id), |
| } |
| } |
| |
| fn static_mutability(tcx: TyCtxt<'_>, def_id: DefId) -> Option<hir::Mutability> { |
| match tcx.hir().get_if_local(def_id) { |
| Some( |
| Node::Item(&hir::Item { kind: hir::ItemKind::Static(_, mutbl, _), .. }) |
| | Node::ForeignItem(&hir::ForeignItem { |
| kind: hir::ForeignItemKind::Static(_, mutbl), |
| .. |
| }), |
| ) => Some(mutbl), |
| Some(_) => None, |
| _ => bug!("static_mutability applied to non-local def-id {:?}", def_id), |
| } |
| } |
| |
| fn generator_kind(tcx: TyCtxt<'_>, def_id: DefId) -> Option<hir::GeneratorKind> { |
| match tcx.hir().get_if_local(def_id) { |
| Some(Node::Expr(&rustc_hir::Expr { |
| kind: rustc_hir::ExprKind::Closure(_, _, body_id, _, _), |
| .. |
| })) => tcx.hir().body(body_id).generator_kind(), |
| Some(_) => None, |
| _ => bug!("generator_kind applied to non-local def-id {:?}", def_id), |
| } |
| } |
| |
| fn from_target_feature( |
| tcx: TyCtxt<'_>, |
| id: DefId, |
| attr: &ast::Attribute, |
| supported_target_features: &FxHashMap<String, Option<Symbol>>, |
| target_features: &mut Vec<Symbol>, |
| ) { |
| let list = match attr.meta_item_list() { |
| Some(list) => list, |
| None => return, |
| }; |
| let bad_item = |span| { |
| let msg = "malformed `target_feature` attribute input"; |
| let code = "enable = \"..\"".to_owned(); |
| tcx.sess |
| .struct_span_err(span, &msg) |
| .span_suggestion(span, "must be of the form", code, Applicability::HasPlaceholders) |
| .emit(); |
| }; |
| let rust_features = tcx.features(); |
| for item in list { |
| // Only `enable = ...` is accepted in the meta-item list. |
| if !item.has_name(sym::enable) { |
| bad_item(item.span()); |
| continue; |
| } |
| |
| // Must be of the form `enable = "..."` (a string). |
| let value = match item.value_str() { |
| Some(value) => value, |
| None => { |
| bad_item(item.span()); |
| continue; |
| } |
| }; |
| |
| // We allow comma separation to enable multiple features. |
| target_features.extend(value.as_str().split(',').filter_map(|feature| { |
| let feature_gate = match supported_target_features.get(feature) { |
| Some(g) => g, |
| None => { |
| let msg = |
| format!("the feature named `{}` is not valid for this target", feature); |
| let mut err = tcx.sess.struct_span_err(item.span(), &msg); |
| err.span_label( |
| item.span(), |
| format!("`{}` is not valid for this target", feature), |
| ); |
| if let Some(stripped) = feature.strip_prefix('+') { |
| let valid = supported_target_features.contains_key(stripped); |
| if valid { |
| err.help("consider removing the leading `+` in the feature name"); |
| } |
| } |
| err.emit(); |
| return None; |
| } |
| }; |
| |
| // Only allow features whose feature gates have been enabled. |
| let allowed = match feature_gate.as_ref().copied() { |
| Some(sym::arm_target_feature) => rust_features.arm_target_feature, |
| Some(sym::aarch64_target_feature) => rust_features.aarch64_target_feature, |
| Some(sym::hexagon_target_feature) => rust_features.hexagon_target_feature, |
| Some(sym::powerpc_target_feature) => rust_features.powerpc_target_feature, |
| Some(sym::mips_target_feature) => rust_features.mips_target_feature, |
| Some(sym::riscv_target_feature) => rust_features.riscv_target_feature, |
| Some(sym::avx512_target_feature) => rust_features.avx512_target_feature, |
| Some(sym::sse4a_target_feature) => rust_features.sse4a_target_feature, |
| Some(sym::tbm_target_feature) => rust_features.tbm_target_feature, |
| Some(sym::wasm_target_feature) => rust_features.wasm_target_feature, |
| Some(sym::cmpxchg16b_target_feature) => rust_features.cmpxchg16b_target_feature, |
| Some(sym::adx_target_feature) => rust_features.adx_target_feature, |
| Some(sym::movbe_target_feature) => rust_features.movbe_target_feature, |
| Some(sym::rtm_target_feature) => rust_features.rtm_target_feature, |
| Some(sym::f16c_target_feature) => rust_features.f16c_target_feature, |
| Some(sym::ermsb_target_feature) => rust_features.ermsb_target_feature, |
| Some(name) => bug!("unknown target feature gate {}", name), |
| None => true, |
| }; |
| if !allowed && id.is_local() { |
| feature_err( |
| &tcx.sess.parse_sess, |
| feature_gate.unwrap(), |
| item.span(), |
| &format!("the target feature `{}` is currently unstable", feature), |
| ) |
| .emit(); |
| } |
| Some(Symbol::intern(feature)) |
| })); |
| } |
| } |
| |
| fn linkage_by_name(tcx: TyCtxt<'_>, def_id: DefId, name: &str) -> Linkage { |
| use rustc_middle::mir::mono::Linkage::*; |
| |
| // Use the names from src/llvm/docs/LangRef.rst here. Most types are only |
| // applicable to variable declarations and may not really make sense for |
| // Rust code in the first place but allow them anyway and trust that the |
| // user knows what s/he's doing. Who knows, unanticipated use cases may pop |
| // up in the future. |
| // |
| // ghost, dllimport, dllexport and linkonce_odr_autohide are not supported |
| // and don't have to be, LLVM treats them as no-ops. |
| match name { |
| "appending" => Appending, |
| "available_externally" => AvailableExternally, |
| "common" => Common, |
| "extern_weak" => ExternalWeak, |
| "external" => External, |
| "internal" => Internal, |
| "linkonce" => LinkOnceAny, |
| "linkonce_odr" => LinkOnceODR, |
| "private" => Private, |
| "weak" => WeakAny, |
| "weak_odr" => WeakODR, |
| _ => { |
| let span = tcx.hir().span_if_local(def_id); |
| if let Some(span) = span { |
| tcx.sess.span_fatal(span, "invalid linkage specified") |
| } else { |
| tcx.sess.fatal(&format!("invalid linkage specified: {}", name)) |
| } |
| } |
| } |
| } |
| |
| fn codegen_fn_attrs(tcx: TyCtxt<'_>, id: DefId) -> CodegenFnAttrs { |
| let attrs = tcx.get_attrs(id); |
| |
| let mut codegen_fn_attrs = CodegenFnAttrs::new(); |
| if should_inherit_track_caller(tcx, id) { |
| codegen_fn_attrs.flags |= CodegenFnAttrFlags::TRACK_CALLER; |
| } |
| |
| let supported_target_features = tcx.supported_target_features(LOCAL_CRATE); |
| |
| let mut inline_span = None; |
| let mut link_ordinal_span = None; |
| let mut no_sanitize_span = None; |
| for attr in attrs.iter() { |
| if tcx.sess.check_name(attr, sym::cold) { |
| codegen_fn_attrs.flags |= CodegenFnAttrFlags::COLD; |
| } else if tcx.sess.check_name(attr, sym::rustc_allocator) { |
| codegen_fn_attrs.flags |= CodegenFnAttrFlags::ALLOCATOR; |
| } else if tcx.sess.check_name(attr, sym::unwind) { |
| codegen_fn_attrs.flags |= CodegenFnAttrFlags::UNWIND; |
| } else if tcx.sess.check_name(attr, sym::ffi_returns_twice) { |
| if tcx.is_foreign_item(id) { |
| codegen_fn_attrs.flags |= CodegenFnAttrFlags::FFI_RETURNS_TWICE; |
| } else { |
| // `#[ffi_returns_twice]` is only allowed `extern fn`s. |
| struct_span_err!( |
| tcx.sess, |
| attr.span, |
| E0724, |
| "`#[ffi_returns_twice]` may only be used on foreign functions" |
| ) |
| .emit(); |
| } |
| } else if tcx.sess.check_name(attr, sym::ffi_pure) { |
| if tcx.is_foreign_item(id) { |
| if attrs.iter().any(|a| tcx.sess.check_name(a, sym::ffi_const)) { |
| // `#[ffi_const]` functions cannot be `#[ffi_pure]` |
| struct_span_err!( |
| tcx.sess, |
| attr.span, |
| E0757, |
| "`#[ffi_const]` function cannot be `#[ffi_pure]`" |
| ) |
| .emit(); |
| } else { |
| codegen_fn_attrs.flags |= CodegenFnAttrFlags::FFI_PURE; |
| } |
| } else { |
| // `#[ffi_pure]` is only allowed on foreign functions |
| struct_span_err!( |
| tcx.sess, |
| attr.span, |
| E0755, |
| "`#[ffi_pure]` may only be used on foreign functions" |
| ) |
| .emit(); |
| } |
| } else if tcx.sess.check_name(attr, sym::ffi_const) { |
| if tcx.is_foreign_item(id) { |
| codegen_fn_attrs.flags |= CodegenFnAttrFlags::FFI_CONST; |
| } else { |
| // `#[ffi_const]` is only allowed on foreign functions |
| struct_span_err!( |
| tcx.sess, |
| attr.span, |
| E0756, |
| "`#[ffi_const]` may only be used on foreign functions" |
| ) |
| .emit(); |
| } |
| } else if tcx.sess.check_name(attr, sym::rustc_allocator_nounwind) { |
| codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_ALLOCATOR_NOUNWIND; |
| } else if tcx.sess.check_name(attr, sym::naked) { |
| codegen_fn_attrs.flags |= CodegenFnAttrFlags::NAKED; |
| } else if tcx.sess.check_name(attr, sym::no_mangle) { |
| codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_MANGLE; |
| } else if tcx.sess.check_name(attr, sym::rustc_std_internal_symbol) { |
| codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL; |
| } else if tcx.sess.check_name(attr, sym::used) { |
| codegen_fn_attrs.flags |= CodegenFnAttrFlags::USED; |
| } else if tcx.sess.check_name(attr, sym::cmse_nonsecure_entry) { |
| if !matches!(tcx.fn_sig(id).abi(), abi::Abi::C { .. }) { |
| struct_span_err!( |
| tcx.sess, |
| attr.span, |
| E0776, |
| "`#[cmse_nonsecure_entry]` requires C ABI" |
| ) |
| .emit(); |
| } |
| if !tcx.sess.target.llvm_target.contains("thumbv8m") { |
| struct_span_err!(tcx.sess, attr.span, E0775, "`#[cmse_nonsecure_entry]` is only valid for targets with the TrustZone-M extension") |
| .emit(); |
| } |
| codegen_fn_attrs.flags |= CodegenFnAttrFlags::CMSE_NONSECURE_ENTRY; |
| } else if tcx.sess.check_name(attr, sym::thread_local) { |
| codegen_fn_attrs.flags |= CodegenFnAttrFlags::THREAD_LOCAL; |
| } else if tcx.sess.check_name(attr, sym::track_caller) { |
| if tcx.is_closure(id) || tcx.fn_sig(id).abi() != abi::Abi::Rust { |
| struct_span_err!(tcx.sess, attr.span, E0737, "`#[track_caller]` requires Rust ABI") |
| .emit(); |
| } |
| codegen_fn_attrs.flags |= CodegenFnAttrFlags::TRACK_CALLER; |
| } else if tcx.sess.check_name(attr, sym::export_name) { |
| if let Some(s) = attr.value_str() { |
| if s.as_str().contains('\0') { |
| // `#[export_name = ...]` will be converted to a null-terminated string, |
| // so it may not contain any null characters. |
| struct_span_err!( |
| tcx.sess, |
| attr.span, |
| E0648, |
| "`export_name` may not contain null characters" |
| ) |
| .emit(); |
| } |
| codegen_fn_attrs.export_name = Some(s); |
| } |
| } else if tcx.sess.check_name(attr, sym::target_feature) { |
| if !tcx.is_closure(id) && tcx.fn_sig(id).unsafety() == hir::Unsafety::Normal { |
| if !tcx.features().target_feature_11 { |
| let mut err = feature_err( |
| &tcx.sess.parse_sess, |
| sym::target_feature_11, |
| attr.span, |
| "`#[target_feature(..)]` can only be applied to `unsafe` functions", |
| ); |
| err.span_label(tcx.def_span(id), "not an `unsafe` function"); |
| err.emit(); |
| } else if let Some(local_id) = id.as_local() { |
| check_target_feature_trait_unsafe(tcx, local_id, attr.span); |
| } |
| } |
| from_target_feature( |
| tcx, |
| id, |
| attr, |
| &supported_target_features, |
| &mut codegen_fn_attrs.target_features, |
| ); |
| } else if tcx.sess.check_name(attr, sym::linkage) { |
| if let Some(val) = attr.value_str() { |
| codegen_fn_attrs.linkage = Some(linkage_by_name(tcx, id, &val.as_str())); |
| } |
| } else if tcx.sess.check_name(attr, sym::link_section) { |
| if let Some(val) = attr.value_str() { |
| if val.as_str().bytes().any(|b| b == 0) { |
| let msg = format!( |
| "illegal null byte in link_section \ |
| value: `{}`", |
| &val |
| ); |
| tcx.sess.span_err(attr.span, &msg); |
| } else { |
| codegen_fn_attrs.link_section = Some(val); |
| } |
| } |
| } else if tcx.sess.check_name(attr, sym::link_name) { |
| codegen_fn_attrs.link_name = attr.value_str(); |
| } else if tcx.sess.check_name(attr, sym::link_ordinal) { |
| link_ordinal_span = Some(attr.span); |
| if let ordinal @ Some(_) = check_link_ordinal(tcx, attr) { |
| codegen_fn_attrs.link_ordinal = ordinal; |
| } |
| } else if tcx.sess.check_name(attr, sym::no_sanitize) { |
| no_sanitize_span = Some(attr.span); |
| if let Some(list) = attr.meta_item_list() { |
| for item in list.iter() { |
| if item.has_name(sym::address) { |
| codegen_fn_attrs.no_sanitize |= SanitizerSet::ADDRESS; |
| } else if item.has_name(sym::memory) { |
| codegen_fn_attrs.no_sanitize |= SanitizerSet::MEMORY; |
| } else if item.has_name(sym::thread) { |
| codegen_fn_attrs.no_sanitize |= SanitizerSet::THREAD; |
| } else if item.has_name(sym::hwaddress) { |
| codegen_fn_attrs.no_sanitize |= SanitizerSet::HWADDRESS; |
| } else { |
| tcx.sess |
| .struct_span_err(item.span(), "invalid argument for `no_sanitize`") |
| .note("expected one of: `address`, `hwaddress`, `memory` or `thread`") |
| .emit(); |
| } |
| } |
| } |
| } else if tcx.sess.check_name(attr, sym::instruction_set) { |
| codegen_fn_attrs.instruction_set = match attr.meta().map(|i| i.kind) { |
| Some(MetaItemKind::List(ref items)) => match items.as_slice() { |
| [NestedMetaItem::MetaItem(set)] => { |
| let segments = |
| set.path.segments.iter().map(|x| x.ident.name).collect::<Vec<_>>(); |
| match segments.as_slice() { |
| [sym::arm, sym::a32] | [sym::arm, sym::t32] => { |
| if !tcx.sess.target.has_thumb_interworking { |
| struct_span_err!( |
| tcx.sess.diagnostic(), |
| attr.span, |
| E0779, |
| "target does not support `#[instruction_set]`" |
| ) |
| .emit(); |
| None |
| } else if segments[1] == sym::a32 { |
| Some(InstructionSetAttr::ArmA32) |
| } else if segments[1] == sym::t32 { |
| Some(InstructionSetAttr::ArmT32) |
| } else { |
| unreachable!() |
| } |
| } |
| _ => { |
| struct_span_err!( |
| tcx.sess.diagnostic(), |
| attr.span, |
| E0779, |
| "invalid instruction set specified", |
| ) |
| .emit(); |
| None |
| } |
| } |
| } |
| [] => { |
| struct_span_err!( |
| tcx.sess.diagnostic(), |
| attr.span, |
| E0778, |
| "`#[instruction_set]` requires an argument" |
| ) |
| .emit(); |
| None |
| } |
| _ => { |
| struct_span_err!( |
| tcx.sess.diagnostic(), |
| attr.span, |
| E0779, |
| "cannot specify more than one instruction set" |
| ) |
| .emit(); |
| None |
| } |
| }, |
| _ => { |
| struct_span_err!( |
| tcx.sess.diagnostic(), |
| attr.span, |
| E0778, |
| "must specify an instruction set" |
| ) |
| .emit(); |
| None |
| } |
| }; |
| } else if tcx.sess.check_name(attr, sym::repr) { |
| codegen_fn_attrs.alignment = match attr.meta_item_list() { |
| Some(items) => match items.as_slice() { |
| [item] => match item.name_value_literal() { |
| Some((sym::align, literal)) => { |
| let alignment = rustc_attr::parse_alignment(&literal.kind); |
| |
| match alignment { |
| Ok(align) => Some(align), |
| Err(msg) => { |
| struct_span_err!( |
| tcx.sess.diagnostic(), |
| attr.span, |
| E0589, |
| "invalid `repr(align)` attribute: {}", |
| msg |
| ) |
| .emit(); |
| |
| None |
| } |
| } |
| } |
| _ => None, |
| }, |
| [] => None, |
| _ => None, |
| }, |
| None => None, |
| }; |
| } |
| } |
| |
| codegen_fn_attrs.inline = attrs.iter().fold(InlineAttr::None, |ia, attr| { |
| if !attr.has_name(sym::inline) { |
| return ia; |
| } |
| match attr.meta().map(|i| i.kind) { |
| Some(MetaItemKind::Word) => { |
| tcx.sess.mark_attr_used(attr); |
| InlineAttr::Hint |
| } |
| Some(MetaItemKind::List(ref items)) => { |
| tcx.sess.mark_attr_used(attr); |
| inline_span = Some(attr.span); |
| if items.len() != 1 { |
| struct_span_err!( |
| tcx.sess.diagnostic(), |
| attr.span, |
| E0534, |
| "expected one argument" |
| ) |
| .emit(); |
| InlineAttr::None |
| } else if list_contains_name(&items[..], sym::always) { |
| InlineAttr::Always |
| } else if list_contains_name(&items[..], sym::never) { |
| InlineAttr::Never |
| } else { |
| struct_span_err!( |
| tcx.sess.diagnostic(), |
| items[0].span(), |
| E0535, |
| "invalid argument" |
| ) |
| .emit(); |
| |
| InlineAttr::None |
| } |
| } |
| Some(MetaItemKind::NameValue(_)) => ia, |
| None => ia, |
| } |
| }); |
| |
| codegen_fn_attrs.optimize = attrs.iter().fold(OptimizeAttr::None, |ia, attr| { |
| if !attr.has_name(sym::optimize) { |
| return ia; |
| } |
| let err = |sp, s| struct_span_err!(tcx.sess.diagnostic(), sp, E0722, "{}", s).emit(); |
| match attr.meta().map(|i| i.kind) { |
| Some(MetaItemKind::Word) => { |
| err(attr.span, "expected one argument"); |
| ia |
| } |
| Some(MetaItemKind::List(ref items)) => { |
| tcx.sess.mark_attr_used(attr); |
| inline_span = Some(attr.span); |
| if items.len() != 1 { |
| err(attr.span, "expected one argument"); |
| OptimizeAttr::None |
| } else if list_contains_name(&items[..], sym::size) { |
| OptimizeAttr::Size |
| } else if list_contains_name(&items[..], sym::speed) { |
| OptimizeAttr::Speed |
| } else { |
| err(items[0].span(), "invalid argument"); |
| OptimizeAttr::None |
| } |
| } |
| Some(MetaItemKind::NameValue(_)) => ia, |
| None => ia, |
| } |
| }); |
| |
| // #73631: closures inherit `#[target_feature]` annotations |
| if tcx.features().target_feature_11 && tcx.is_closure(id) { |
| let owner_id = tcx.parent(id).expect("closure should have a parent"); |
| codegen_fn_attrs |
| .target_features |
| .extend(tcx.codegen_fn_attrs(owner_id).target_features.iter().copied()) |
| } |
| |
| // If a function uses #[target_feature] it can't be inlined into general |
| // purpose functions as they wouldn't have the right target features |
| // enabled. For that reason we also forbid #[inline(always)] as it can't be |
| // respected. |
| if !codegen_fn_attrs.target_features.is_empty() { |
| if codegen_fn_attrs.inline == InlineAttr::Always { |
| if let Some(span) = inline_span { |
| tcx.sess.span_err( |
| span, |
| "cannot use `#[inline(always)]` with \ |
| `#[target_feature]`", |
| ); |
| } |
| } |
| } |
| |
| if !codegen_fn_attrs.no_sanitize.is_empty() { |
| if codegen_fn_attrs.inline == InlineAttr::Always { |
| if let (Some(no_sanitize_span), Some(inline_span)) = (no_sanitize_span, inline_span) { |
| let hir_id = tcx.hir().local_def_id_to_hir_id(id.expect_local()); |
| tcx.struct_span_lint_hir( |
| lint::builtin::INLINE_NO_SANITIZE, |
| hir_id, |
| no_sanitize_span, |
| |lint| { |
| lint.build("`no_sanitize` will have no effect after inlining") |
| .span_note(inline_span, "inlining requested here") |
| .emit(); |
| }, |
| ) |
| } |
| } |
| } |
| |
| // Weak lang items have the same semantics as "std internal" symbols in the |
| // sense that they're preserved through all our LTO passes and only |
| // strippable by the linker. |
| // |
| // Additionally weak lang items have predetermined symbol names. |
| if tcx.is_weak_lang_item(id) { |
| codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL; |
| } |
| let check_name = |attr, sym| tcx.sess.check_name(attr, sym); |
| if let Some(name) = weak_lang_items::link_name(check_name, &attrs) { |
| codegen_fn_attrs.export_name = Some(name); |
| codegen_fn_attrs.link_name = Some(name); |
| } |
| check_link_name_xor_ordinal(tcx, &codegen_fn_attrs, link_ordinal_span); |
| |
| // Internal symbols to the standard library all have no_mangle semantics in |
| // that they have defined symbol names present in the function name. This |
| // also applies to weak symbols where they all have known symbol names. |
| if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL) { |
| codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_MANGLE; |
| } |
| |
| codegen_fn_attrs |
| } |
| |
| /// Checks if the provided DefId is a method in a trait impl for a trait which has track_caller |
| /// applied to the method prototype. |
| fn should_inherit_track_caller(tcx: TyCtxt<'_>, def_id: DefId) -> bool { |
| if let Some(impl_item) = tcx.opt_associated_item(def_id) { |
| if let ty::AssocItemContainer::ImplContainer(impl_def_id) = impl_item.container { |
| if let Some(trait_def_id) = tcx.trait_id_of_impl(impl_def_id) { |
| if let Some(trait_item) = tcx |
| .associated_items(trait_def_id) |
| .filter_by_name_unhygienic(impl_item.ident.name) |
| .find(move |trait_item| { |
| trait_item.kind == ty::AssocKind::Fn |
| && tcx.hygienic_eq(impl_item.ident, trait_item.ident, trait_def_id) |
| }) |
| { |
| return tcx |
| .codegen_fn_attrs(trait_item.def_id) |
| .flags |
| .intersects(CodegenFnAttrFlags::TRACK_CALLER); |
| } |
| } |
| } |
| } |
| |
| false |
| } |
| |
| fn check_link_ordinal(tcx: TyCtxt<'_>, attr: &ast::Attribute) -> Option<usize> { |
| use rustc_ast::{Lit, LitIntType, LitKind}; |
| let meta_item_list = attr.meta_item_list(); |
| let meta_item_list: Option<&[ast::NestedMetaItem]> = meta_item_list.as_ref().map(Vec::as_ref); |
| let sole_meta_list = match meta_item_list { |
| Some([item]) => item.literal(), |
| _ => None, |
| }; |
| if let Some(Lit { kind: LitKind::Int(ordinal, LitIntType::Unsuffixed), .. }) = sole_meta_list { |
| if *ordinal <= usize::MAX as u128 { |
| Some(*ordinal as usize) |
| } else { |
| let msg = format!("ordinal value in `link_ordinal` is too large: `{}`", &ordinal); |
| tcx.sess |
| .struct_span_err(attr.span, &msg) |
| .note("the value may not exceed `usize::MAX`") |
| .emit(); |
| None |
| } |
| } else { |
| tcx.sess |
| .struct_span_err(attr.span, "illegal ordinal format in `link_ordinal`") |
| .note("an unsuffixed integer value, e.g., `1`, is expected") |
| .emit(); |
| None |
| } |
| } |
| |
| fn check_link_name_xor_ordinal( |
| tcx: TyCtxt<'_>, |
| codegen_fn_attrs: &CodegenFnAttrs, |
| inline_span: Option<Span>, |
| ) { |
| if codegen_fn_attrs.link_name.is_none() || codegen_fn_attrs.link_ordinal.is_none() { |
| return; |
| } |
| let msg = "cannot use `#[link_name]` with `#[link_ordinal]`"; |
| if let Some(span) = inline_span { |
| tcx.sess.span_err(span, msg); |
| } else { |
| tcx.sess.err(msg); |
| } |
| } |
| |
| /// Checks the function annotated with `#[target_feature]` is not a safe |
| /// trait method implementation, reporting an error if it is. |
| fn check_target_feature_trait_unsafe(tcx: TyCtxt<'_>, id: LocalDefId, attr_span: Span) { |
| let hir_id = tcx.hir().local_def_id_to_hir_id(id); |
| let node = tcx.hir().get(hir_id); |
| if let Node::ImplItem(hir::ImplItem { kind: hir::ImplItemKind::Fn(..), .. }) = node { |
| let parent_id = tcx.hir().get_parent_item(hir_id); |
| let parent_item = tcx.hir().expect_item(parent_id); |
| if let hir::ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }) = parent_item.kind { |
| tcx.sess |
| .struct_span_err( |
| attr_span, |
| "`#[target_feature(..)]` cannot be applied to safe trait method", |
| ) |
| .span_label(attr_span, "cannot be applied to safe trait method") |
| .span_label(tcx.def_span(id), "not an `unsafe` function") |
| .emit(); |
| } |
| } |
| } |