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Diffstat (limited to '')
| -rw-r--r-- | compiler/rustc_typeck/src/collect.rs | 3361 |
1 files changed, 0 insertions, 3361 deletions
diff --git a/compiler/rustc_typeck/src/collect.rs b/compiler/rustc_typeck/src/collect.rs deleted file mode 100644 index 99996e80c..000000000 --- a/compiler/rustc_typeck/src/collect.rs +++ /dev/null @@ -1,3361 +0,0 @@ -//! "Collection" is the process of determining the type and other external -//! details of each item in Rust. Collection is specifically concerned -//! with *inter-procedural* things -- for example, for a function -//! definition, collection will figure out the type and signature of the -//! function, but it will not visit the *body* of the function in any way, -//! nor examine type annotations on local variables (that's the job of -//! type *checking*). -//! -//! Collecting is ultimately defined by a bundle of queries that -//! inquire after various facts about the items in the crate (e.g., -//! `type_of`, `generics_of`, `predicates_of`, etc). See the `provide` function -//! for the full set. -//! -//! At present, however, we do run collection across all items in the -//! crate as a kind of pass. This should eventually be factored away. - -use crate::astconv::AstConv; -use crate::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, DiagnosticBuilder, ErrorGuaranteed}; -use rustc_hir as hir; -use rustc_hir::def::{CtorKind, DefKind}; -use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_ID, LOCAL_CRATE}; -use rustc_hir::intravisit::{self, Visitor}; -use rustc_hir::weak_lang_items; -use rustc_hir::{GenericParamKind, HirId, Node}; -use rustc_middle::hir::nested_filter; -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, IsSuggestable, Ty, TyCtxt}; -use rustc_middle::ty::{ReprOptions, ToPredicate}; -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; - -#[derive(Debug)] -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 }); -} - -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, - 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, - generator_kind, - codegen_fn_attrs, - asm_target_features, - collect_mod_item_types, - should_inherit_track_caller, - ..*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)] -pub(crate) struct HirPlaceholderCollector(pub(crate) Vec<Span>); - -impl<'v> Visitor<'v> for HirPlaceholderCollector { - fn visit_ty(&mut self, t: &'v hir::Ty<'v>) { - if let hir::TyKind::Infer = t.kind { - self.0.push(t.span); - } - intravisit::walk_ty(self, t) - } - fn visit_generic_arg(&mut self, generic_arg: &'v hir::GenericArg<'v>) { - match generic_arg { - hir::GenericArg::Infer(inf) => { - self.0.push(inf.span); - intravisit::walk_inf(self, inf); - } - hir::GenericArg::Type(t) => self.visit_ty(t), - _ => {} - } - } - fn visit_array_length(&mut self, length: &'v hir::ArrayLen) { - if let &hir::ArrayLen::Infer(_, span) = length { - self.0.push(span); - } - intravisit::walk_array_len(self, length) - } -} - -struct CollectItemTypesVisitor<'tcx> { - tcx: TyCtxt<'tcx>, -} - -/// If there are any placeholder types (`_`), emit an error explaining that this is not allowed -/// and suggest adding type parameters in the appropriate place, taking into consideration any and -/// all already existing generic type parameters to avoid suggesting a name that is already in use. -pub(crate) fn placeholder_type_error<'tcx>( - tcx: TyCtxt<'tcx>, - generics: Option<&hir::Generics<'_>>, - placeholder_types: Vec<Span>, - suggest: bool, - hir_ty: Option<&hir::Ty<'_>>, - kind: &'static str, -) { - if placeholder_types.is_empty() { - return; - } - - placeholder_type_error_diag(tcx, generics, placeholder_types, vec![], suggest, hir_ty, kind) - .emit(); -} - -pub(crate) fn placeholder_type_error_diag<'tcx>( - tcx: TyCtxt<'tcx>, - generics: Option<&hir::Generics<'_>>, - placeholder_types: Vec<Span>, - additional_spans: Vec<Span>, - suggest: bool, - hir_ty: Option<&hir::Ty<'_>>, - kind: &'static str, -) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> { - if placeholder_types.is_empty() { - return bad_placeholder(tcx, additional_spans, kind); - } - - let params = generics.map(|g| g.params).unwrap_or_default(); - let type_name = params.next_type_param_name(None); - let mut sugg: Vec<_> = - placeholder_types.iter().map(|sp| (*sp, (*type_name).to_string())).collect(); - - if let Some(generics) = generics { - if let Some(arg) = params.iter().find(|arg| { - matches!(arg.name, hir::ParamName::Plain(Ident { name: kw::Underscore, .. })) - }) { - // Account for `_` already present in cases like `struct S<_>(_);` and suggest - // `struct S<T>(T);` instead of `struct S<_, T>(T);`. - sugg.push((arg.span, (*type_name).to_string())); - } else if let Some(span) = generics.span_for_param_suggestion() { - // Account for bounds, we want `fn foo<T: E, K>(_: K)` not `fn foo<T, K: E>(_: K)`. - sugg.push((span, format!(", {}", type_name))); - } else { - sugg.push((generics.span, format!("<{}>", type_name))); - } - } - - let mut err = - bad_placeholder(tcx, placeholder_types.into_iter().chain(additional_spans).collect(), kind); - - // Suggest, but only if it is not a function in const or static - if suggest { - let mut is_fn = false; - let mut is_const_or_static = false; - - if let Some(hir_ty) = hir_ty && let hir::TyKind::BareFn(_) = hir_ty.kind { - is_fn = true; - - // Check if parent is const or static - let parent_id = tcx.hir().get_parent_node(hir_ty.hir_id); - let parent_node = tcx.hir().get(parent_id); - - is_const_or_static = matches!( - parent_node, - Node::Item(&hir::Item { - kind: hir::ItemKind::Const(..) | hir::ItemKind::Static(..), - .. - }) | Node::TraitItem(&hir::TraitItem { - kind: hir::TraitItemKind::Const(..), - .. - }) | Node::ImplItem(&hir::ImplItem { kind: hir::ImplItemKind::Const(..), .. }) - ); - } - - // if function is wrapped around a const or static, - // then don't show the suggestion - if !(is_fn && is_const_or_static) { - err.multipart_suggestion( - "use type parameters instead", - sugg, - Applicability::HasPlaceholders, - ); - } - } - - err -} - -fn reject_placeholder_type_signatures_in_item<'tcx>( - tcx: TyCtxt<'tcx>, - item: &'tcx hir::Item<'tcx>, -) { - let (generics, suggest) = match &item.kind { - hir::ItemKind::Union(_, generics) - | hir::ItemKind::Enum(_, generics) - | hir::ItemKind::TraitAlias(generics, _) - | hir::ItemKind::Trait(_, _, generics, ..) - | hir::ItemKind::Impl(hir::Impl { generics, .. }) - | hir::ItemKind::Struct(_, generics) => (generics, true), - hir::ItemKind::OpaqueTy(hir::OpaqueTy { generics, .. }) - | hir::ItemKind::TyAlias(_, generics) => (generics, false), - // `static`, `fn` and `const` are handled elsewhere to suggest appropriate type. - _ => return, - }; - - let mut visitor = HirPlaceholderCollector::default(); - visitor.visit_item(item); - - placeholder_type_error(tcx, Some(generics), visitor.0, suggest, None, item.kind.descr()); -} - -impl<'tcx> Visitor<'tcx> for CollectItemTypesVisitor<'tcx> { - type NestedFilter = nested_filter::OnlyBodies; - - fn nested_visit_map(&mut self) -> Self::Map { - self.tcx.hir() - } - - fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) { - convert_item(self.tcx, item.item_id()); - reject_placeholder_type_signatures_in_item(self.tcx, item); - intravisit::walk_item(self, item); - } - - fn visit_generics(&mut self, generics: &'tcx hir::Generics<'tcx>) { - for param in generics.params { - match param.kind { - hir::GenericParamKind::Lifetime { .. } => {} - hir::GenericParamKind::Type { default: Some(_), .. } => { - 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); - // We do not call `type_of` for closures here as that - // depends on typecheck and would therefore hide - // any further errors in case one typeck fails. - } - intravisit::walk_expr(self, expr); - } - - fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem<'tcx>) { - convert_trait_item(self.tcx, trait_item.trait_item_id()); - intravisit::walk_trait_item(self, trait_item); - } - - fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem<'tcx>) { - convert_impl_item(self.tcx, impl_item.impl_item_id()); - intravisit::walk_impl_item(self, impl_item); - } -} - -/////////////////////////////////////////////////////////////////////////// -// Utility types and common code for the above passes. - -fn bad_placeholder<'tcx>( - tcx: TyCtxt<'tcx>, - mut spans: Vec<Span>, - kind: &'static str, -) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> { - let kind = if kind.ends_with('s') { format!("{}es", kind) } else { format!("{}s", kind) }; - - spans.sort(); - let mut err = struct_span_err!( - tcx.sess, - spans.clone(), - E0121, - "the placeholder `_` is not allowed within types on item signatures for {}", - kind - ); - for span in spans { - err.span_label(span, "not allowed in type signatures"); - } - err -} - -impl<'tcx> 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<'tcx> 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 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) -> Const<'tcx> { - let ty = self.tcx.fold_regions(ty, |r, _| match *r { - ty::ReErased => self.tcx.lifetimes.re_static, - _ => r, - }); - self.tcx().const_error_with_message(ty, span, "bad placeholder constant") - } - - fn projected_ty_from_poly_trait_ref( - &self, - span: Span, - item_def_id: DefId, - item_segment: &hir::PathSegment<'_>, - poly_trait_ref: ty::PolyTraitRef<'tcx>, - ) -> Ty<'tcx> { - if let Some(trait_ref) = poly_trait_ref.no_bound_vars() { - let item_substs = <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.with_hi(item_segment.ident.span.lo()), - format!( - "{}::", - // Replace the existing lifetimes with a new named lifetime. - self.tcx.replace_late_bound_regions_uncached( - poly_trait_ref, - |_| { - self.tcx.mk_region(ty::ReEarlyBound( - ty::EarlyBoundRegion { - def_id: item_def_id, - index: 0, - name: Symbol::intern(<_name), - }, - )) - } - ), - ), - ), - ]; - 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_verbose( - span.with_hi(item_segment.ident.span.lo()), - "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(), - ), - 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(def_id); - let generics = tcx.generics_of(param_owner); - 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(def_id)); - - // Don't look for bounds where the type parameter isn't in scope. - let parent = if item_def_id == param_owner.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, - origin: hir::OpaqueTyOrigin::TyAlias, - .. - }) - | 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<'tcx> 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. - #[instrument(level = "trace", skip(self, ast_generics))] - 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 param_def_id = self.tcx.hir().local_def_id(param_id).to_def_id(); - debug!(?param_def_id); - ast_generics - .predicates - .iter() - .filter_map(|wp| match *wp { - hir::WherePredicate::BoundPredicate(ref bp) => Some(bp), - _ => None, - }) - .flat_map(|bp| { - let bt = if bp.is_param_bound(param_def_id) { - Some(ty) - } else if !only_self_bounds.0 { - Some(self.to_ty(bp.bounded_ty)) - } else { - None - }; - let bvars = self.tcx.late_bound_vars(bp.bounded_ty.hir_id); - - bp.bounds.iter().filter_map(move |b| bt.map(|bt| (bt, b, bvars))).filter( - |(_, b, _)| match assoc_name { - Some(assoc_name) => self.bound_defines_assoc_item(b, assoc_name), - None => true, - }, - ) - }) - .flat_map(|(bt, b, bvars)| predicates_from_bound(self, bt, b, bvars)) - .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, - } - } -} - -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::Macro(..) - | hir::ItemKind::Mod(_) - | hir::ItemKind::GlobalAsm(_) => {} - hir::ItemKind::ForeignMod { items, .. } => { - for item in items { - let item = tcx.hir().foreign_item(item.id); - tcx.ensure().generics_of(item.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 = HirPlaceholderCollector::default(); - visitor.visit_foreign_item(item); - placeholder_type_error( - tcx, - None, - visitor.0, - false, - None, - "static variable", - ); - } - _ => (), - } - } - } - 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 { - origin: hir::OpaqueTyOrigin::FnReturn(..) | hir::OpaqueTyOrigin::AsyncFn(..), - .. - }) => {} - - // 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), - hir::ItemKind::Const(ty, ..) | hir::ItemKind::Static(ty, ..) => { - if !is_suggestable_infer_ty(ty) { - let mut visitor = HirPlaceholderCollector::default(); - visitor.visit_item(it); - placeholder_type_error(tcx, None, visitor.0, false, None, it.kind.descr()); - } - } - _ => (), - } - } - } -} - -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 = HirPlaceholderCollector::default(); - visitor.visit_trait_item(trait_item); - placeholder_type_error(tcx, None, visitor.0, false, None, "constant"); - } - - 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 = HirPlaceholderCollector::default(); - visitor.visit_trait_item(trait_item); - placeholder_type_error(tcx, None, visitor.0, false, None, "associated type"); - } - - hir::TraitItemKind::Type(_, None) => { - tcx.ensure().item_bounds(trait_item_id.def_id); - // #74612: Visit and try to find bad placeholders - // even if there is no concrete type. - let mut visitor = HirPlaceholderCollector::default(); - visitor.visit_trait_item(trait_item); - - placeholder_type_error(tcx, None, visitor.0, false, None, "associated type"); - } - }; - - tcx.ensure().predicates_of(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 = HirPlaceholderCollector::default(); - visitor.visit_impl_item(impl_item); - - placeholder_type_error(tcx, None, visitor.0, false, None, "associated type"); - } - hir::ImplItemKind::Const(..) => {} - } -} - -fn convert_variant_ctor(tcx: TyCtxt<'_>, 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(), name: f.ident.name, vis: tcx.visibility(fid) } - }) - .collect(); - let recovered = match def { - hir::VariantData::Struct(_, r) => *r, - _ => false, - }; - ty::VariantDef::new( - ident.name, - 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>(tcx: TyCtxt<'tcx>, def_id: DefId) -> ty::AdtDef<'tcx> { - use rustc_hir::*; - - let def_id = def_id.expect_local(); - let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); - let Node::Item(item) = tcx.hir().get(hir_id) else { - bug!(); - }; - - let repr = 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 Node::Item(item) = tcx.hir().get(trait_hir_id) else { - 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, - assoc_name, - ) - } else { - <dyn AstConv<'_>>::compute_bounds(&icx, self_param_ty, bounds) - }; - - 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)); - debug!(?superbounds); - - // 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 item = tcx.hir().expect_item(def_id.expect_local()); - - let (is_auto, unsafety, items) = match item.kind { - hir::ItemKind::Trait(is_auto, unsafety, .., items) => { - (is_auto == hir::IsAuto::Yes, unsafety, items) - } - hir::ItemKind::TraitAlias(..) => (false, hir::Unsafety::Normal, &[][..]), - _ => span_bug!(item.span, "trait_def_of_item invoked on non-trait"), - }; - - let paren_sugar = tcx.has_attr(def_id, sym::rustc_paren_sugar); - if paren_sugar && !tcx.features().unboxed_closures { - tcx.sess - .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 skip_array_during_method_dispatch = - tcx.has_attr(def_id, sym::rustc_skip_array_during_method_dispatch); - 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 must_implement_one_of = tcx - .get_attr(def_id, sym::rustc_must_implement_one_of) - // Check that there are at least 2 arguments of `#[rustc_must_implement_one_of]` - // and that they are all identifiers - .and_then(|attr| match attr.meta_item_list() { - Some(items) if items.len() < 2 => { - tcx.sess - .struct_span_err( - attr.span, - "the `#[rustc_must_implement_one_of]` attribute must be \ - used with at least 2 args", - ) - .emit(); - - None - } - Some(items) => items - .into_iter() - .map(|item| item.ident().ok_or(item.span())) - .collect::<Result<Box<[_]>, _>>() - .map_err(|span| { - tcx.sess - .struct_span_err(span, "must be a name of an associated function") - .emit(); - }) - .ok() - .zip(Some(attr.span)), - // Error is reported by `rustc_attr!` - None => None, - }) - // Check that all arguments of `#[rustc_must_implement_one_of]` reference - // functions in the trait with default implementations - .and_then(|(list, attr_span)| { - let errors = list.iter().filter_map(|ident| { - let item = items.iter().find(|item| item.ident == *ident); - - match item { - Some(item) if matches!(item.kind, hir::AssocItemKind::Fn { .. }) => { - if !tcx.impl_defaultness(item.id.def_id).has_value() { - tcx.sess - .struct_span_err( - item.span, - "This function doesn't have a default implementation", - ) - .span_note(attr_span, "required by this annotation") - .emit(); - - return Some(()); - } - - return None; - } - Some(item) => { - tcx.sess - .struct_span_err(item.span, "Not a function") - .span_note(attr_span, "required by this annotation") - .note( - "All `#[rustc_must_implement_one_of]` arguments \ - must be associated function names", - ) - .emit(); - } - None => { - tcx.sess - .struct_span_err(ident.span, "Function not found in this trait") - .emit(); - } - } - - Some(()) - }); - - (errors.count() == 0).then_some(list) - }) - // Check for duplicates - .and_then(|list| { - let mut set: FxHashMap<Symbol, Span> = FxHashMap::default(); - let mut no_dups = true; - - for ident in &*list { - if let Some(dup) = set.insert(ident.name, ident.span) { - tcx.sess - .struct_span_err(vec![dup, ident.span], "Functions names are duplicated") - .note( - "All `#[rustc_must_implement_one_of]` arguments \ - must be unique", - ) - .emit(); - - no_dups = false; - } - } - - no_dups.then_some(list) - }); - - ty::TraitDef::new( - def_id, - unsafety, - paren_sugar, - is_auto, - is_marker, - skip_array_during_method_dispatch, - spec_kind, - must_implement_one_of, - ) -} - -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<'tcx> Visitor<'tcx> for LateBoundRegionsDetector<'tcx> { - 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, _, _)) if debruijn < self.outer_index => {} - Some(rl::Region::LateBound(..) | 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(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 AnonConstInParamTyDetector { - in_param_ty: bool, - found_anon_const_in_param_ty: bool, - ct: HirId, -} - -impl<'v> Visitor<'v> for AnonConstInParamTyDetector { - fn visit_generic_param(&mut self, p: &'v hir::GenericParam<'v>) { - if let GenericParamKind::Const { ty, default: _ } = p.kind { - let prev = self.in_param_ty; - self.in_param_ty = true; - self.visit_ty(ty); - self.in_param_ty = prev; - } - } - - fn visit_anon_const(&mut self, c: &'v hir::AnonConst) { - if self.in_param_ty && self.ct == c.hir_id { - self.found_anon_const_in_param_ty = 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(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_def_id = tcx.hir().get_parent_item(hir_id); - - let mut in_param_ty = false; - for (_parent, node) in tcx.hir().parent_iter(hir_id) { - if let Some(generics) = node.generics() { - let mut visitor = AnonConstInParamTyDetector { - in_param_ty: false, - found_anon_const_in_param_ty: false, - ct: hir_id, - }; - - visitor.visit_generics(generics); - in_param_ty = visitor.found_anon_const_in_param_ty; - break; - } - } - - if in_param_ty { - // We do not allow generic parameters in anon consts if we are inside - // of a const parameter type, e.g. `struct Foo<const N: usize, const M: [u8; N]>` is not allowed. - None - } else if tcx.lazy_normalization() { - if let Some(param_id) = tcx.hir().opt_const_param_default_param_hir_id(hir_id) { - // If the def_id we are calling generics_of on is an anon ct default i.e: - // - // struct Foo<const N: usize = { .. }>; - // ^^^ ^ ^^^^^^ def id of this anon const - // ^ ^ param_id - // ^ parent_def_id - // - // then we only want to return generics for params to the left of `N`. If we don't do that we - // end up with that const looking like: `ty::ConstKind::Unevaluated(def_id, substs: [N#0])`. - // - // This causes ICEs (#86580) when building the substs for Foo in `fn foo() -> Foo { .. }` as - // we substitute the defaults with the partially built substs when we build the substs. Subst'ing - // the `N#0` on the unevaluated const indexes into the empty substs we're in the process of building. - // - // We fix this by having this function return the parent's generics ourselves and truncating the - // generics to only include non-forward declared params (with the exception of the `Self` ty) - // - // For the above code example that means we want `substs: []` - // For the following struct def we want `substs: [N#0]` when generics_of is called on - // the def id of the `{ N + 1 }` anon const - // struct Foo<const N: usize, const M: usize = { N + 1 }>; - // - // This has some implications for how we get the predicates available to the anon const - // see `explicit_predicates_of` for more information on this - let generics = tcx.generics_of(parent_def_id.to_def_id()); - let param_def = tcx.hir().local_def_id(param_id).to_def_id(); - let param_def_idx = generics.param_def_id_to_index[¶m_def]; - // In the above example this would be .params[..N#0] - let params = generics.params[..param_def_idx as usize].to_owned(); - let param_def_id_to_index = - params.iter().map(|param| (param.def_id, param.index)).collect(); - - return ty::Generics { - // we set the parent of these generics to be our parent's parent so that we - // dont end up with substs: [N, M, N] for the const default on a struct like this: - // struct Foo<const N: usize, const M: usize = { ... }>; - parent: generics.parent, - parent_count: generics.parent_count, - params, - param_def_id_to_index, - has_self: generics.has_self, - has_late_bound_regions: generics.has_late_bound_regions, - }; - } - - // HACK(eddyb) this provides the correct generics when - // `feature(generic_const_expressions)` 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), .. }) - if constant.hir_id() == hir_id => - { - Some(parent_def_id.to_def_id()) - } - Node::Variant(Variant { disr_expr: Some(ref constant), .. }) - if constant.hir_id == hir_id => - { - Some(parent_def_id.to_def_id()) - } - Node::Expr(&Expr { kind: ExprKind::ConstBlock(_), .. }) => { - Some(tcx.typeck_root_def_id(def_id)) - } - // Exclude `GlobalAsm` here which cannot have generics. - Node::Expr(&Expr { kind: ExprKind::InlineAsm(asm), .. }) - if asm.operands.iter().any(|(op, _op_sp)| match op { - hir::InlineAsmOperand::Const { anon_const } - | hir::InlineAsmOperand::SymFn { anon_const } => { - anon_const.hir_id == hir_id - } - _ => false, - }) => - { - Some(parent_def_id.to_def_id()) - } - _ => None, - } - } - } - Node::Expr(&hir::Expr { kind: hir::ExprKind::Closure { .. }, .. }) => { - Some(tcx.typeck_root_def_id(def_id)) - } - Node::Item(item) => match item.kind { - ItemKind::OpaqueTy(hir::OpaqueTy { - origin: - hir::OpaqueTyOrigin::FnReturn(fn_def_id) | hir::OpaqueTyOrigin::AsyncFn(fn_def_id), - .. - }) => Some(fn_def_id.to_def_id()), - ItemKind::OpaqueTy(hir::OpaqueTy { origin: hir::OpaqueTyOrigin::TyAlias, .. }) => { - let parent_id = tcx.hir().get_parent_item(hir_id); - assert_ne!(parent_id, CRATE_DEF_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(parent_id.to_def_id()) - } - _ => None, - }, - _ => None, - }; - - let no_generics = hir::Generics::empty(); - let ast_generics = node.generics().unwrap_or(&no_generics); - let (opt_self, allow_defaults) = match node { - Node::Item(item) => { - match item.kind { - ItemKind::Trait(..) | ItemKind::TraitAlias(..) => { - // 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 opt_self = Some(ty::GenericParamDef { - index: 0, - name: kw::SelfUpper, - def_id, - pure_wrt_drop: false, - kind: ty::GenericParamDefKind::Type { - has_default: false, - object_lifetime_default: rl::Set1::Empty, - synthetic: false, - }, - }); - - (opt_self, true) - } - ItemKind::TyAlias(..) - | ItemKind::Enum(..) - | ItemKind::Struct(..) - | ItemKind::OpaqueTy(..) - | ItemKind::Union(..) => (None, true), - _ => (None, false), - } - } - _ => (None, false), - }; - - 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!(!has_self); - 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.owner); - - // 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(hir::Closure { movability: 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: false, - }, - })); - } - - // provide junk type parameter defs for const blocks. - if let Node::AnonConst(_) = node { - let parent_node = tcx.hir().get(tcx.hir().get_parent_node(hir_id)); - if let Node::Expr(&Expr { kind: ExprKind::ConstBlock(_), .. }) = parent_node { - params.push(ty::GenericParamDef { - index: type_start, - name: Symbol::intern("<const_ty>"), - def_id, - pure_wrt_drop: false, - kind: ty::GenericParamDefKind::Type { - has_default: false, - object_lifetime_default: rl::Set1::Empty, - synthetic: false, - }, - }); - } - } - - 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().any(|arg| match arg { - hir::GenericArg::Type(ty) => is_suggestable_infer_ty(ty), - hir::GenericArg::Infer(_) => true, - _ => false, - }) -} - -/// Whether `ty` is a type with `_` placeholders that can be inferred. Used in diagnostics only to -/// use inference to provide suggestions for the appropriate type if possible. -fn is_suggestable_infer_ty(ty: &hir::Ty<'_>) -> bool { - debug!(?ty); - use hir::TyKind::*; - match &ty.kind { - Infer => true, - Slice(ty) => is_suggestable_infer_ty(ty), - Array(ty, length) => { - is_suggestable_infer_ty(ty) || matches!(length, hir::ArrayLen::Infer(_, _)) - } - Tup(tys) => tys.iter().any(is_suggestable_infer_ty), - Ptr(mut_ty) | 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<'hir>(output: &'hir hir::FnRetTy<'hir>) -> Option<&'hir hir::Ty<'hir>> { - if let hir::FnRetTy::Return(ty) = output { - if is_suggestable_infer_ty(ty) { - return Some(&*ty); - } - } - None -} - -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(_)), - generics, - .. - }) - | Item(hir::Item { kind: ItemKind::Fn(sig, generics, _), .. }) => { - infer_return_ty_for_fn_sig(tcx, sig, generics, def_id, &icx) - } - - ImplItem(hir::ImplItem { kind: ImplItemKind::Fn(sig, _), generics, .. }) => { - // Do not try to inference the return type for a impl method coming from a trait - if let Item(hir::Item { kind: ItemKind::Impl(i), .. }) = - tcx.hir().get(tcx.hir().get_parent_node(hir_id)) - && i.of_trait.is_some() - { - <dyn AstConv<'_>>::ty_of_fn( - &icx, - hir_id, - sig.header.unsafety, - sig.header.abi, - sig.decl, - Some(generics), - None, - ) - } else { - infer_return_ty_for_fn_sig(tcx, sig, generics, def_id, &icx) - } - } - - TraitItem(hir::TraitItem { - kind: TraitItemKind::Fn(FnSig { header, decl, span: _ }, _), - generics, - .. - }) => <dyn AstConv<'_>>::ty_of_fn( - &icx, - hir_id, - header.unsafety, - header.abi, - decl, - Some(generics), - None, - ), - - ForeignItem(&hir::ForeignItem { kind: ForeignItemKind::Fn(fn_decl, _, _), .. }) => { - let abi = tcx.hir().get_foreign_abi(hir_id); - compute_sig_of_foreign_fn_decl(tcx, def_id.to_def_id(), fn_decl, abi) - } - - Ctor(data) | Variant(hir::Variant { data, .. }) if data.ctor_hir_id().is_some() => { - let ty = tcx.type_of(tcx.hir().get_parent_item(hir_id)); - let inputs = - data.fields().iter().map(|f| tcx.type_of(tcx.hir().local_def_id(f.hir_id))); - ty::Binder::dummy(tcx.mk_fn_sig( - inputs, - ty, - false, - hir::Unsafety::Normal, - abi::Abi::Rust, - )) - } - - Expr(&hir::Expr { kind: hir::ExprKind::Closure { .. }, .. }) => { - // Closure signatures are not like other function - // signatures and cannot be accessed through `fn_sig`. For - // example, a closure signature excludes the `self` - // argument. In any case they are embedded within the - // closure type as part of the `ClosureSubsts`. - // - // To get the signature of a closure, you should use the - // `sig` method on the `ClosureSubsts`: - // - // substs.as_closure().sig(def_id, tcx) - bug!( - "to get the signature of a closure, use `substs.as_closure().sig()` not `fn_sig()`", - ); - } - - x => { - bug!("unexpected sort of node in fn_sig(): {:?}", x); - } - } -} - -fn infer_return_ty_for_fn_sig<'tcx>( - tcx: TyCtxt<'tcx>, - sig: &hir::FnSig<'_>, - generics: &hir::Generics<'_>, - def_id: LocalDefId, - icx: &ItemCtxt<'tcx>, -) -> ty::PolyFnSig<'tcx> { - let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); - - match get_infer_ret_ty(&sig.decl.output) { - Some(ty) => { - let fn_sig = tcx.typeck(def_id).liberated_fn_sigs()[hir_id]; - // Typeck doesn't expect erased regions to be returned from `type_of`. - let fn_sig = tcx.fold_regions(fn_sig, |r, _| match *r { - ty::ReErased => tcx.lifetimes.re_static, - _ => r, - }); - let fn_sig = ty::Binder::dummy(fn_sig); - - let mut visitor = HirPlaceholderCollector::default(); - visitor.visit_ty(ty); - let mut diag = bad_placeholder(tcx, visitor.0, "return type"); - let ret_ty = fn_sig.skip_binder().output(); - if ret_ty.is_suggestable(tcx, false) { - diag.span_suggestion( - ty.span, - "replace with the correct return type", - ret_ty, - Applicability::MachineApplicable, - ); - } else if matches!(ret_ty.kind(), ty::FnDef(..)) { - let fn_sig = ret_ty.fn_sig(tcx); - if fn_sig - .skip_binder() - .inputs_and_output - .iter() - .all(|t| t.is_suggestable(tcx, false)) - { - diag.span_suggestion( - ty.span, - "replace with the correct return type", - fn_sig, - Applicability::MachineApplicable, - ); - } - } else if ret_ty.is_closure() { - // 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(); - - fn_sig - } - None => <dyn AstConv<'_>>::ty_of_fn( - icx, - hir_id, - sig.header.unsafety, - sig.header.abi, - sig.decl, - Some(generics), - None, - ), - } -} - -fn impl_trait_ref(tcx: TyCtxt<'_>, def_id: DefId) -> Option<ty::TraitRef<'_>> { - let icx = ItemCtxt::new(tcx, def_id); - match tcx.hir().expect_item(def_id.expect_local()).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 is_rustc_reservation = tcx.has_attr(def_id, sym::rustc_reservation_impl); - let item = tcx.hir().expect_item(def_id.expect_local()); - 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. - // - // We use a DUMMY_SP here as a way to signal trait bounds that come - // from the trait itself that *shouldn't* be shown as the source of - // an obligation and instead be skipped. Otherwise we'd use - // `tcx.def_span(def_id);` - - let constness = if tcx.has_attr(def_id, sym::const_trait) { - ty::BoundConstness::ConstIfConst - } else { - ty::BoundConstness::NotConst - }; - - let span = rustc_span::DUMMY_SP; - result.predicates = - tcx.arena.alloc_from_iter(result.predicates.iter().copied().chain(std::iter::once(( - ty::TraitRef::identity(tcx, def_id).with_constness(constness).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); - - 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).map(ty::Binder::dummy); - } - &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 { - origin: hir::OpaqueTyOrigin::AsyncFn(..) | hir::OpaqueTyOrigin::FnReturn(..), - .. - }) => { - // 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: &[] }; - } - ItemKind::OpaqueTy(OpaqueTy { - ref generics, - origin: hir::OpaqueTyOrigin::TyAlias, - .. - }) => { - // 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.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 - + early_bound_lifetimes_from_generics(tcx, ast_generics).count() as u32; - - // 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 mut bounds = Bounds::default(); - // Params are implicitly sized unless a `?Sized` bound is found - <dyn AstConv<'_>>::add_implicitly_sized( - &icx, - &mut bounds, - &[], - Some((param.hir_id, ast_generics.predicates)), - param.span, - ); - predicates.extend(bounds.predicates(tcx, param_ty)); - } - GenericParamKind::Const { .. } => { - // Bounds on const parameters are currently not possible. - index += 1; - } - } - } - - // Add in the bounds that appear in the where-clause. - for predicate in ast_generics.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 predicate = ty::Binder::bind_with_vars( - ty::PredicateKind::WellFormed(ty.into()), - bound_vars, - ); - predicates.insert((predicate.to_predicate(tcx), span)); - } - } - - let mut bounds = Bounds::default(); - <dyn AstConv<'_>>::add_bounds( - &icx, - ty, - bound_pred.bounds.iter(), - &mut bounds, - bound_vars, - ); - predicates.extend(bounds.predicates(tcx, ty)); - } - - 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::Binder::dummy(ty::PredicateKind::RegionOutlives( - ty::OutlivesPredicate(r1, r2), - )) - .to_predicate(icx.tcx); - - (pred, span) - })) - } - - hir::WherePredicate::EqPredicate(..) => { - // FIXME(#20041) - } - } - } - - if tcx.features().generic_const_exprs { - 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> { - 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.kind() { - assert_eq!(uv.promoted, None); - let span = self.tcx.hir().span(c.hir_id); - self.preds.insert(( - ty::Binder::dummy(ty::PredicateKind::ConstEvaluatable(uv.shrink())) - .to_predicate(self.tcx), - span, - )); - } - } - - fn visit_const_param_default(&mut self, _param: HirId, _ct: &'tcx hir::AnonConst) { - // Do not look into const param defaults, - // these get checked when they are actually instantiated. - // - // We do not want the following to error: - // - // struct Foo<const N: usize, const M: usize = { N + 1 }>; - // struct Bar<const N: usize>(Foo<N, 3>); - } - } - - 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 && 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>(tcx: TyCtxt<'tcx>, def_id: DefId) -> ty::GenericPredicates<'tcx> { - let def_kind = tcx.def_kind(def_id); - if let DefKind::Trait = def_kind { - // 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<'tcx>| { - // 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(tcx) == 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 { - if matches!(def_kind, DefKind::AnonConst) && tcx.lazy_normalization() { - let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local()); - if tcx.hir().opt_const_param_default_param_hir_id(hir_id).is_some() { - // In `generics_of` we set the generics' parent to be our parent's parent which means that - // we lose out on the predicates of our actual parent if we dont return those predicates here. - // (See comment in `generics_of` for more information on why the parent shenanigans is necessary) - // - // struct Foo<T, const N: usize = { <T as Trait>::ASSOC }>(T) where T: Trait; - // ^^^ ^^^^^^^^^^^^^^^^^^^^^^^ the def id we are calling - // ^^^ explicit_predicates_of on - // parent item we dont have set as the - // parent of generics returned by `generics_of` - // - // In the above code we want the anon const to have predicates in its param env for `T: Trait` - let item_def_id = tcx.hir().get_parent_item(hir_id); - // In the above code example we would be calling `explicit_predicates_of(Foo)` here - return tcx.explicit_predicates_of(item_def_id); - } - } - gather_explicit_predicates_of(tcx, def_id) - } -} - -/// 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>, - bound_vars: &'tcx ty::List<ty::BoundVariableKind>, -) -> Vec<(ty::Predicate<'tcx>, Span)> { - let mut bounds = Bounds::default(); - astconv.add_bounds(param_ty, [bound].into_iter(), &mut bounds, bound_vars); - bounds.predicates(astconv.tcx(), param_ty).collect() -} - -fn compute_sig_of_foreign_fn_decl<'tcx>( - tcx: TyCtxt<'tcx>, - def_id: DefId, - decl: &'tcx hir::FnDecl<'tcx>, - abi: abi::Abi, -) -> 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, - None, - None, - ); - - // Feature gate SIMD types in FFI, since I am not sure that the - // ABIs are handled at all correctly. -huonw - if abi != abi::Abi::RustIntrinsic - && abi != abi::Abi::PlatformIntrinsic - && !tcx.features().simd_ffi - { - let check = |ast_ty: &hir::Ty<'_>, ty: Ty<'_>| { - if ty.is_simd() { - let snip = tcx - .sess - .source_map() - .span_to_snippet(ast_ty.span) - .map_or_else(|_| String::new(), |s| format!(" `{}`", s)); - tcx.sess - .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 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(&rustc_hir::Closure { body, .. }), - .. - })) => tcx.hir().body(body).generator_kind(), - Some(_) => None, - _ => bug!("generator_kind applied to non-local def-id {:?}", def_id), - } -} - -fn from_target_feature( - tcx: TyCtxt<'_>, - attr: &ast::Attribute, - supported_target_features: &FxHashMap<String, Option<Symbol>>, - target_features: &mut Vec<Symbol>, -) { - let Some(list) = attr.meta_item_list() else { return }; - let bad_item = |span| { - let msg = "malformed `target_feature` attribute input"; - let code = "enable = \"..\""; - 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 Some(value) = item.value_str() else { - bad_item(item.span()); - continue; - }; - - // We allow comma separation to enable multiple features. - target_features.extend(value.as_str().split(',').filter_map(|feature| { - let Some(feature_gate) = supported_target_features.get(feature) else { - 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::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::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(sym::bpf_target_feature) => rust_features.bpf_target_feature, - Some(sym::aarch64_ver_target_feature) => rust_features.aarch64_ver_target_feature, - Some(name) => bug!("unknown target feature gate {}", name), - None => true, - }; - if !allowed { - 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: LocalDefId, 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 they're 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, - _ => tcx.sess.span_fatal(tcx.def_span(def_id), "invalid linkage specified"), - } -} - -fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: DefId) -> CodegenFnAttrs { - if cfg!(debug_assertions) { - let def_kind = tcx.def_kind(did); - assert!( - def_kind.has_codegen_attrs(), - "unexpected `def_kind` in `codegen_fn_attrs`: {def_kind:?}", - ); - } - - let did = did.expect_local(); - let attrs = tcx.hir().attrs(tcx.hir().local_def_id_to_hir_id(did)); - let mut codegen_fn_attrs = CodegenFnAttrs::new(); - if tcx.should_inherit_track_caller(did) { - codegen_fn_attrs.flags |= CodegenFnAttrFlags::TRACK_CALLER; - } - - // The panic_no_unwind function called by TerminatorKind::Abort will never - // unwind. If the panic handler that it invokes unwind then it will simply - // call the panic handler again. - if Some(did.to_def_id()) == tcx.lang_items().panic_no_unwind() { - codegen_fn_attrs.flags |= CodegenFnAttrFlags::NEVER_UNWIND; - } - - 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 attr.has_name(sym::cold) { - codegen_fn_attrs.flags |= CodegenFnAttrFlags::COLD; - } else if attr.has_name(sym::rustc_allocator) { - codegen_fn_attrs.flags |= CodegenFnAttrFlags::ALLOCATOR; - } else if attr.has_name(sym::ffi_returns_twice) { - if tcx.is_foreign_item(did) { - 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 attr.has_name(sym::ffi_pure) { - if tcx.is_foreign_item(did) { - if attrs.iter().any(|a| a.has_name(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 attr.has_name(sym::ffi_const) { - if tcx.is_foreign_item(did) { - 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 attr.has_name(sym::rustc_allocator_nounwind) { - codegen_fn_attrs.flags |= CodegenFnAttrFlags::NEVER_UNWIND; - } else if attr.has_name(sym::rustc_reallocator) { - codegen_fn_attrs.flags |= CodegenFnAttrFlags::REALLOCATOR; - } else if attr.has_name(sym::rustc_deallocator) { - codegen_fn_attrs.flags |= CodegenFnAttrFlags::DEALLOCATOR; - } else if attr.has_name(sym::rustc_allocator_zeroed) { - codegen_fn_attrs.flags |= CodegenFnAttrFlags::ALLOCATOR_ZEROED; - } else if attr.has_name(sym::naked) { - codegen_fn_attrs.flags |= CodegenFnAttrFlags::NAKED; - } else if attr.has_name(sym::no_mangle) { - codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_MANGLE; - } else if attr.has_name(sym::no_coverage) { - codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_COVERAGE; - } else if attr.has_name(sym::rustc_std_internal_symbol) { - codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL; - } else if attr.has_name(sym::used) { - let inner = attr.meta_item_list(); - match inner.as_deref() { - Some([item]) if item.has_name(sym::linker) => { - if !tcx.features().used_with_arg { - feature_err( - &tcx.sess.parse_sess, - sym::used_with_arg, - attr.span, - "`#[used(linker)]` is currently unstable", - ) - .emit(); - } - codegen_fn_attrs.flags |= CodegenFnAttrFlags::USED_LINKER; - } - Some([item]) if item.has_name(sym::compiler) => { - if !tcx.features().used_with_arg { - feature_err( - &tcx.sess.parse_sess, - sym::used_with_arg, - attr.span, - "`#[used(compiler)]` is currently unstable", - ) - .emit(); - } - codegen_fn_attrs.flags |= CodegenFnAttrFlags::USED; - } - Some(_) => { - tcx.sess - .struct_span_err( - attr.span, - "expected `used`, `used(compiler)` or `used(linker)`", - ) - .emit(); - } - None => { - // Unfortunately, unconditionally using `llvm.used` causes - // issues in handling `.init_array` with the gold linker, - // but using `llvm.compiler.used` caused a nontrival amount - // of unintentional ecosystem breakage -- particularly on - // Mach-O targets. - // - // As a result, we emit `llvm.compiler.used` only on ELF - // targets. This is somewhat ad-hoc, but actually follows - // our pre-LLVM 13 behavior (prior to the ecosystem - // breakage), and seems to match `clang`'s behavior as well - // (both before and after LLVM 13), possibly because they - // have similar compatibility concerns to us. See - // https://github.com/rust-lang/rust/issues/47384#issuecomment-1019080146 - // and following comments for some discussion of this, as - // well as the comments in `rustc_codegen_llvm` where these - // flags are handled. - // - // Anyway, to be clear: this is still up in the air - // somewhat, and is subject to change in the future (which - // is a good thing, because this would ideally be a bit - // more firmed up). - let is_like_elf = !(tcx.sess.target.is_like_osx - || tcx.sess.target.is_like_windows - || tcx.sess.target.is_like_wasm); - codegen_fn_attrs.flags |= if is_like_elf { - CodegenFnAttrFlags::USED - } else { - CodegenFnAttrFlags::USED_LINKER - }; - } - } - } else if attr.has_name(sym::cmse_nonsecure_entry) { - if !matches!(tcx.fn_sig(did).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 attr.has_name(sym::thread_local) { - codegen_fn_attrs.flags |= CodegenFnAttrFlags::THREAD_LOCAL; - } else if attr.has_name(sym::track_caller) { - if !tcx.is_closure(did.to_def_id()) && tcx.fn_sig(did).abi() != abi::Abi::Rust { - struct_span_err!(tcx.sess, attr.span, E0737, "`#[track_caller]` requires Rust ABI") - .emit(); - } - if tcx.is_closure(did.to_def_id()) && !tcx.features().closure_track_caller { - feature_err( - &tcx.sess.parse_sess, - sym::closure_track_caller, - attr.span, - "`#[track_caller]` on closures is currently unstable", - ) - .emit(); - } - codegen_fn_attrs.flags |= CodegenFnAttrFlags::TRACK_CALLER; - } else if attr.has_name(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 attr.has_name(sym::target_feature) { - if !tcx.is_closure(did.to_def_id()) - && tcx.fn_sig(did).unsafety() == hir::Unsafety::Normal - { - if tcx.sess.target.is_like_wasm || tcx.sess.opts.actually_rustdoc { - // The `#[target_feature]` attribute is allowed on - // WebAssembly targets on all functions, including safe - // ones. Other targets require that `#[target_feature]` is - // only applied to unsafe functions (pending the - // `target_feature_11` feature) because on most targets - // execution of instructions that are not supported is - // considered undefined behavior. For WebAssembly which is a - // 100% safe target at execution time it's not possible to - // execute undefined instructions, and even if a future - // feature was added in some form for this it would be a - // deterministic trap. There is no undefined behavior when - // executing WebAssembly so `#[target_feature]` is allowed - // on safe functions (but again, only for WebAssembly) - // - // Note that this is also allowed if `actually_rustdoc` so - // if a target is documenting some wasm-specific code then - // it's not spuriously denied. - } else 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(did), "not an `unsafe` function"); - err.emit(); - } else { - check_target_feature_trait_unsafe(tcx, did, attr.span); - } - } - from_target_feature( - tcx, - attr, - supported_target_features, - &mut codegen_fn_attrs.target_features, - ); - } else if attr.has_name(sym::linkage) { - if let Some(val) = attr.value_str() { - codegen_fn_attrs.linkage = Some(linkage_by_name(tcx, did, val.as_str())); - } - } else if attr.has_name(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 attr.has_name(sym::link_name) { - codegen_fn_attrs.link_name = attr.value_str(); - } else if attr.has_name(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 attr.has_name(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::cfi) { - codegen_fn_attrs.no_sanitize |= SanitizerSet::CFI; - } else if item.has_name(sym::memory) { - codegen_fn_attrs.no_sanitize |= SanitizerSet::MEMORY; - } else if item.has_name(sym::memtag) { - codegen_fn_attrs.no_sanitize |= SanitizerSet::MEMTAG; - } else if item.has_name(sym::shadow_call_stack) { - codegen_fn_attrs.no_sanitize |= SanitizerSet::SHADOWCALLSTACK; - } 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`, `cfi`, `hwaddress`, `memory`, `memtag`, `shadow-call-stack`, or `thread`") - .emit(); - } - } - } - } else if attr.has_name(sym::instruction_set) { - codegen_fn_attrs.instruction_set = match attr.meta_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 attr.has_name(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_kind() { - Some(MetaItemKind::Word) => InlineAttr::Hint, - Some(MetaItemKind::List(ref items)) => { - 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_kind() { - Some(MetaItemKind::Word) => { - err(attr.span, "expected one argument"); - ia - } - Some(MetaItemKind::List(ref items)) => { - 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(did.to_def_id()) { - let owner_id = tcx.parent(did.to_def_id()); - if tcx.def_kind(owner_id).has_codegen_attrs() { - 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(did); - 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(did.to_def_id()) { - codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL; - } - if let Some(name) = weak_lang_items::link_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; - } - - // Any linkage to LLVM intrinsics for now forcibly marks them all as never - // unwinds since LLVM sometimes can't handle codegen which `invoke`s - // intrinsic functions. - if let Some(name) = &codegen_fn_attrs.link_name { - if name.as_str().starts_with("llvm.") { - codegen_fn_attrs.flags |= CodegenFnAttrFlags::NEVER_UNWIND; - } - } - - codegen_fn_attrs -} - -/// Computes the set of target features used in a function for the purposes of -/// inline assembly. -fn asm_target_features<'tcx>(tcx: TyCtxt<'tcx>, did: DefId) -> &'tcx FxHashSet<Symbol> { - let mut target_features = tcx.sess.unstable_target_features.clone(); - if tcx.def_kind(did).has_codegen_attrs() { - let attrs = tcx.codegen_fn_attrs(did); - target_features.extend(&attrs.target_features); - match attrs.instruction_set { - None => {} - Some(InstructionSetAttr::ArmA32) => { - target_features.remove(&sym::thumb_mode); - } - Some(InstructionSetAttr::ArmT32) => { - target_features.insert(sym::thumb_mode); - } - } - } - - tcx.arena.alloc(target_features) -} - -/// 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) - && let ty::AssocItemContainer::ImplContainer = impl_item.container - && let Some(trait_item) = impl_item.trait_item_def_id - { - return tcx - .codegen_fn_attrs(trait_item) - .flags - .intersects(CodegenFnAttrFlags::TRACK_CALLER); - } - - false -} - -fn check_link_ordinal(tcx: TyCtxt<'_>, attr: &ast::Attribute) -> Option<u16> { - 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(), - Some(_) => { - tcx.sess - .struct_span_err(attr.span, "incorrect number of arguments to `#[link_ordinal]`") - .note("the attribute requires exactly one argument") - .emit(); - return None; - } - _ => None, - }; - if let Some(Lit { kind: LitKind::Int(ordinal, LitIntType::Unsuffixed), .. }) = sole_meta_list { - // According to the table at https://docs.microsoft.com/en-us/windows/win32/debug/pe-format#import-header, - // the ordinal must fit into 16 bits. Similarly, the Ordinal field in COFFShortExport (defined - // in llvm/include/llvm/Object/COFFImportFile.h), which we use to communicate import information - // to LLVM for `#[link(kind = "raw-dylib"_])`, is also defined to be uint16_t. - // - // FIXME: should we allow an ordinal of 0? The MSVC toolchain has inconsistent support for this: - // both LINK.EXE and LIB.EXE signal errors and abort when given a .DEF file that specifies - // a zero ordinal. However, llvm-dlltool is perfectly happy to generate an import library - // for such a .DEF file, and MSVC's LINK.EXE is also perfectly happy to consume an import - // library produced by LLVM with an ordinal of 0, and it generates an .EXE. (I don't know yet - // if the resulting EXE runs, as I haven't yet built the necessary DLL -- see earlier comment - // about LINK.EXE failing.) - if *ordinal <= u16::MAX as u128 { - Some(*ordinal as u16) - } 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 `u16::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(); - } - } -} |