1 //! "Collection" is the process of determining the type and other external
2 //! details of each item in Rust. Collection is specifically concerned
3 //! with *inter-procedural* things -- for example, for a function
4 //! definition, collection will figure out the type and signature of the
5 //! function, but it will not visit the *body* of the function in any way,
6 //! nor examine type annotations on local variables (that's the job of
9 //! Collecting is ultimately defined by a bundle of queries that
10 //! inquire after various facts about the items in the crate (e.g.,
11 //! `type_of`, `generics_of`, `predicates_of`, etc). See the `provide` function
14 //! At present, however, we do run collection across all items in the
15 //! crate as a kind of pass. This should eventually be factored away.
17 use crate::astconv::AstConv;
18 use crate::bounds::Bounds;
19 use crate::check::intrinsic::intrinsic_operation_unsafety;
20 use crate::constrained_generic_params as cgp;
22 use crate::middle::resolve_lifetime as rl;
24 use rustc_ast::Attribute;
25 use rustc_ast::{MetaItemKind, NestedMetaItem};
26 use rustc_attr::{list_contains_name, InlineAttr, InstructionSetAttr, OptimizeAttr};
27 use rustc_data_structures::captures::Captures;
28 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexSet};
29 use rustc_errors::{struct_span_err, Applicability};
31 use rustc_hir::def::{CtorKind, DefKind};
32 use rustc_hir::def_id::{DefId, LocalDefId, LOCAL_CRATE};
33 use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
34 use rustc_hir::weak_lang_items;
35 use rustc_hir::{GenericParamKind, HirId, Node};
36 use rustc_middle::hir::map::Map;
37 use rustc_middle::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs};
38 use rustc_middle::mir::mono::Linkage;
39 use rustc_middle::ty::query::Providers;
40 use rustc_middle::ty::subst::InternalSubsts;
41 use rustc_middle::ty::util::Discr;
42 use rustc_middle::ty::util::IntTypeExt;
43 use rustc_middle::ty::{self, AdtKind, Const, DefIdTree, Ty, TyCtxt};
44 use rustc_middle::ty::{ReprOptions, ToPredicate, TypeFoldable};
45 use rustc_session::lint;
46 use rustc_session::parse::feature_err;
47 use rustc_span::symbol::{kw, sym, Ident, Symbol};
48 use rustc_span::{Span, DUMMY_SP};
49 use rustc_target::spec::{abi, PanicStrategy, SanitizerSet};
50 use rustc_trait_selection::traits::error_reporting::suggestions::NextTypeParamName;
56 struct OnlySelfBounds(bool);
58 ///////////////////////////////////////////////////////////////////////////
61 fn collect_mod_item_types(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
62 tcx.hir().visit_item_likes_in_module(
64 &mut CollectItemTypesVisitor { tcx }.as_deep_visitor(),
68 pub fn provide(providers: &mut Providers) {
69 *providers = Providers {
70 opt_const_param_of: type_of::opt_const_param_of,
71 default_anon_const_substs: type_of::default_anon_const_substs,
72 type_of: type_of::type_of,
73 item_bounds: item_bounds::item_bounds,
74 explicit_item_bounds: item_bounds::explicit_item_bounds,
77 predicates_defined_on,
78 explicit_predicates_of,
80 super_predicates_that_define_assoc_type,
81 trait_explicit_predicates_and_bounds,
82 type_param_predicates,
92 collect_mod_item_types,
93 should_inherit_track_caller,
98 ///////////////////////////////////////////////////////////////////////////
100 /// Context specific to some particular item. This is what implements
101 /// `AstConv`. It has information about the predicates that are defined
102 /// on the trait. Unfortunately, this predicate information is
103 /// available in various different forms at various points in the
104 /// process. So we can't just store a pointer to e.g., the AST or the
105 /// parsed ty form, we have to be more flexible. To this end, the
106 /// `ItemCtxt` is parameterized by a `DefId` that it uses to satisfy
107 /// `get_type_parameter_bounds` requests, drawing the information from
108 /// the AST (`hir::Generics`), recursively.
109 pub struct ItemCtxt<'tcx> {
114 ///////////////////////////////////////////////////////////////////////////
117 crate struct PlaceholderHirTyCollector(crate Vec<Span>);
119 impl<'v> Visitor<'v> for PlaceholderHirTyCollector {
120 type Map = intravisit::ErasedMap<'v>;
122 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
123 NestedVisitorMap::None
125 fn visit_ty(&mut self, t: &'v hir::Ty<'v>) {
126 if let hir::TyKind::Infer = t.kind {
129 intravisit::walk_ty(self, t)
131 fn visit_generic_arg(&mut self, generic_arg: &'v hir::GenericArg<'v>) {
133 hir::GenericArg::Infer(inf) => {
134 self.0.push(inf.span);
135 intravisit::walk_inf(self, inf);
137 hir::GenericArg::Type(t) => self.visit_ty(t),
143 struct CollectItemTypesVisitor<'tcx> {
147 /// If there are any placeholder types (`_`), emit an error explaining that this is not allowed
148 /// and suggest adding type parameters in the appropriate place, taking into consideration any and
149 /// all already existing generic type parameters to avoid suggesting a name that is already in use.
150 crate fn placeholder_type_error<'tcx>(
153 generics: &[hir::GenericParam<'_>],
154 placeholder_types: Vec<Span>,
156 hir_ty: Option<&hir::Ty<'_>>,
159 if placeholder_types.is_empty() {
163 let type_name = generics.next_type_param_name(None);
164 let mut sugg: Vec<_> =
165 placeholder_types.iter().map(|sp| (*sp, (*type_name).to_string())).collect();
167 if generics.is_empty() {
168 if let Some(span) = span {
169 sugg.push((span, format!("<{}>", type_name)));
171 } else if let Some(arg) = generics
173 .find(|arg| matches!(arg.name, hir::ParamName::Plain(Ident { name: kw::Underscore, .. })))
175 // Account for `_` already present in cases like `struct S<_>(_);` and suggest
176 // `struct S<T>(T);` instead of `struct S<_, T>(T);`.
177 sugg.push((arg.span, (*type_name).to_string()));
179 let last = generics.iter().last().unwrap();
180 // Account for bounds, we want `fn foo<T: E, K>(_: K)` not `fn foo<T, K: E>(_: K)`.
181 let span = last.bounds_span_for_suggestions().unwrap_or(last.span.shrink_to_hi());
182 sugg.push((span, format!(", {}", type_name)));
185 let mut err = bad_placeholder(tcx, "type", placeholder_types, kind);
187 // Suggest, but only if it is not a function in const or static
189 let mut is_fn = false;
190 let mut is_const_or_static = false;
192 if let Some(hir_ty) = hir_ty {
193 if let hir::TyKind::BareFn(_) = hir_ty.kind {
196 // Check if parent is const or static
197 let parent_id = tcx.hir().get_parent_node(hir_ty.hir_id);
198 let parent_node = tcx.hir().get(parent_id);
200 is_const_or_static = matches!(
202 Node::Item(&hir::Item {
203 kind: hir::ItemKind::Const(..) | hir::ItemKind::Static(..),
205 }) | Node::TraitItem(&hir::TraitItem {
206 kind: hir::TraitItemKind::Const(..),
208 }) | Node::ImplItem(&hir::ImplItem { kind: hir::ImplItemKind::Const(..), .. })
213 // if function is wrapped around a const or static,
214 // then don't show the suggestion
215 if !(is_fn && is_const_or_static) {
216 err.multipart_suggestion(
217 "use type parameters instead",
219 Applicability::HasPlaceholders,
226 fn reject_placeholder_type_signatures_in_item<'tcx>(
228 item: &'tcx hir::Item<'tcx>,
230 let (generics, suggest) = match &item.kind {
231 hir::ItemKind::Union(_, generics)
232 | hir::ItemKind::Enum(_, generics)
233 | hir::ItemKind::TraitAlias(generics, _)
234 | hir::ItemKind::Trait(_, _, generics, ..)
235 | hir::ItemKind::Impl(hir::Impl { generics, .. })
236 | hir::ItemKind::Struct(_, generics) => (generics, true),
237 hir::ItemKind::OpaqueTy(hir::OpaqueTy { generics, .. })
238 | hir::ItemKind::TyAlias(_, generics) => (generics, false),
239 // `static`, `fn` and `const` are handled elsewhere to suggest appropriate type.
243 let mut visitor = PlaceholderHirTyCollector::default();
244 visitor.visit_item(item);
246 placeholder_type_error(
257 impl<'tcx> Visitor<'tcx> for CollectItemTypesVisitor<'tcx> {
258 type Map = Map<'tcx>;
260 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
261 NestedVisitorMap::OnlyBodies(self.tcx.hir())
264 fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) {
265 convert_item(self.tcx, item.item_id());
266 reject_placeholder_type_signatures_in_item(self.tcx, item);
267 intravisit::walk_item(self, item);
270 fn visit_generics(&mut self, generics: &'tcx hir::Generics<'tcx>) {
271 for param in generics.params {
273 hir::GenericParamKind::Lifetime { .. } => {}
274 hir::GenericParamKind::Type { default: Some(_), .. } => {
275 let def_id = self.tcx.hir().local_def_id(param.hir_id);
276 self.tcx.ensure().type_of(def_id);
278 hir::GenericParamKind::Type { .. } => {}
279 hir::GenericParamKind::Const { default, .. } => {
280 let def_id = self.tcx.hir().local_def_id(param.hir_id);
281 self.tcx.ensure().type_of(def_id);
282 if let Some(default) = default {
283 let default_def_id = self.tcx.hir().local_def_id(default.hir_id);
284 // need to store default and type of default
285 self.tcx.ensure().type_of(default_def_id);
286 self.tcx.ensure().const_param_default(def_id);
291 intravisit::walk_generics(self, generics);
294 fn visit_expr(&mut self, expr: &'tcx hir::Expr<'tcx>) {
295 if let hir::ExprKind::Closure(..) = expr.kind {
296 let def_id = self.tcx.hir().local_def_id(expr.hir_id);
297 self.tcx.ensure().generics_of(def_id);
298 // We do not call `type_of` for closures here as that
299 // depends on typecheck and would therefore hide
300 // any further errors in case one typeck fails.
302 intravisit::walk_expr(self, expr);
305 fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem<'tcx>) {
306 convert_trait_item(self.tcx, trait_item.trait_item_id());
307 intravisit::walk_trait_item(self, trait_item);
310 fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem<'tcx>) {
311 convert_impl_item(self.tcx, impl_item.impl_item_id());
312 intravisit::walk_impl_item(self, impl_item);
316 ///////////////////////////////////////////////////////////////////////////
317 // Utility types and common code for the above passes.
319 fn bad_placeholder<'tcx>(
321 placeholder_kind: &'static str,
322 mut spans: Vec<Span>,
324 ) -> rustc_errors::DiagnosticBuilder<'tcx> {
325 let kind = if kind.ends_with('s') { format!("{}es", kind) } else { format!("{}s", kind) };
328 let mut err = struct_span_err!(
332 "the {} placeholder `_` is not allowed within types on item signatures for {}",
337 err.span_label(span, "not allowed in type signatures");
342 impl<'tcx> ItemCtxt<'tcx> {
343 pub fn new(tcx: TyCtxt<'tcx>, item_def_id: DefId) -> ItemCtxt<'tcx> {
344 ItemCtxt { tcx, item_def_id }
347 pub fn to_ty(&self, ast_ty: &hir::Ty<'_>) -> Ty<'tcx> {
348 <dyn AstConv<'_>>::ast_ty_to_ty(self, ast_ty)
351 pub fn hir_id(&self) -> hir::HirId {
352 self.tcx.hir().local_def_id_to_hir_id(self.item_def_id.expect_local())
355 pub fn node(&self) -> hir::Node<'tcx> {
356 self.tcx.hir().get(self.hir_id())
360 impl<'tcx> AstConv<'tcx> for ItemCtxt<'tcx> {
361 fn tcx(&self) -> TyCtxt<'tcx> {
365 fn item_def_id(&self) -> Option<DefId> {
366 Some(self.item_def_id)
369 fn get_type_parameter_bounds(
374 ) -> ty::GenericPredicates<'tcx> {
375 self.tcx.at(span).type_param_predicates((
377 def_id.expect_local(),
382 fn re_infer(&self, _: Option<&ty::GenericParamDef>, _: Span) -> Option<ty::Region<'tcx>> {
386 fn allow_ty_infer(&self) -> bool {
390 fn ty_infer(&self, _: Option<&ty::GenericParamDef>, span: Span) -> Ty<'tcx> {
391 self.tcx().ty_error_with_message(span, "bad_placeholder_type")
397 _: Option<&ty::GenericParamDef>,
399 ) -> &'tcx Const<'tcx> {
400 bad_placeholder(self.tcx(), "const", vec![span], "generic").emit();
401 // Typeck doesn't expect erased regions to be returned from `type_of`.
402 let ty = self.tcx.fold_regions(ty, &mut false, |r, _| match r {
403 ty::ReErased => self.tcx.lifetimes.re_static,
406 self.tcx().const_error(ty)
409 fn projected_ty_from_poly_trait_ref(
413 item_segment: &hir::PathSegment<'_>,
414 poly_trait_ref: ty::PolyTraitRef<'tcx>,
416 if let Some(trait_ref) = poly_trait_ref.no_bound_vars() {
417 let item_substs = <dyn AstConv<'tcx>>::create_substs_for_associated_item(
425 self.tcx().mk_projection(item_def_id, item_substs)
427 // There are no late-bound regions; we can just ignore the binder.
428 let mut err = struct_span_err!(
432 "cannot use the associated type of a trait \
433 with uninferred generic parameters"
437 hir::Node::Field(_) | hir::Node::Ctor(_) | hir::Node::Variant(_) => {
439 self.tcx.hir().expect_item(self.tcx.hir().get_parent_did(self.hir_id()));
441 hir::ItemKind::Enum(_, generics)
442 | hir::ItemKind::Struct(_, generics)
443 | hir::ItemKind::Union(_, generics) => {
444 let lt_name = get_new_lifetime_name(self.tcx, poly_trait_ref, generics);
445 let (lt_sp, sugg) = match generics.params {
446 [] => (generics.span, format!("<{}>", lt_name)),
448 (bound.span.shrink_to_lo(), format!("{}, ", lt_name))
451 let suggestions = vec![
454 span.with_hi(item_segment.ident.span.lo()),
457 // Replace the existing lifetimes with a new named lifetime.
459 .replace_late_bound_regions(poly_trait_ref, |_| {
460 self.tcx.mk_region(ty::ReEarlyBound(
461 ty::EarlyBoundRegion {
464 name: Symbol::intern(<_name),
472 err.multipart_suggestion(
473 "use a fully qualified path with explicit lifetimes",
475 Applicability::MaybeIncorrect,
481 hir::Node::Item(hir::Item {
483 hir::ItemKind::Struct(..) | hir::ItemKind::Enum(..) | hir::ItemKind::Union(..),
487 | hir::Node::ForeignItem(_)
488 | hir::Node::TraitItem(_)
489 | hir::Node::ImplItem(_) => {
490 err.span_suggestion_verbose(
491 span.with_hi(item_segment.ident.span.lo()),
492 "use a fully qualified path with inferred lifetimes",
495 // Erase named lt, we want `<A as B<'_>::C`, not `<A as B<'a>::C`.
496 self.tcx.anonymize_late_bound_regions(poly_trait_ref).skip_binder(),
498 Applicability::MaybeIncorrect,
504 self.tcx().ty_error()
508 fn normalize_ty(&self, _span: Span, ty: Ty<'tcx>) -> Ty<'tcx> {
509 // Types in item signatures are not normalized to avoid undue dependencies.
513 fn set_tainted_by_errors(&self) {
514 // There's no obvious place to track this, so just let it go.
517 fn record_ty(&self, _hir_id: hir::HirId, _ty: Ty<'tcx>, _span: Span) {
518 // There's no place to record types from signatures?
522 /// Synthesize a new lifetime name that doesn't clash with any of the lifetimes already present.
523 fn get_new_lifetime_name<'tcx>(
525 poly_trait_ref: ty::PolyTraitRef<'tcx>,
526 generics: &hir::Generics<'tcx>,
528 let existing_lifetimes = tcx
529 .collect_referenced_late_bound_regions(&poly_trait_ref)
532 if let ty::BoundRegionKind::BrNamed(_, name) = lt {
533 Some(name.as_str().to_string())
538 .chain(generics.params.iter().filter_map(|param| {
539 if let hir::GenericParamKind::Lifetime { .. } = ¶m.kind {
540 Some(param.name.ident().as_str().to_string())
545 .collect::<FxHashSet<String>>();
547 let a_to_z_repeat_n = |n| {
548 (b'a'..=b'z').map(move |c| {
549 let mut s = '\''.to_string();
550 s.extend(std::iter::repeat(char::from(c)).take(n));
555 // If all single char lifetime names are present, we wrap around and double the chars.
556 (1..).flat_map(a_to_z_repeat_n).find(|lt| !existing_lifetimes.contains(lt.as_str())).unwrap()
559 /// Returns the predicates defined on `item_def_id` of the form
560 /// `X: Foo` where `X` is the type parameter `def_id`.
561 fn type_param_predicates(
563 (item_def_id, def_id, assoc_name): (DefId, LocalDefId, Ident),
564 ) -> ty::GenericPredicates<'_> {
567 // In the AST, bounds can derive from two places. Either
568 // written inline like `<T: Foo>` or in a where-clause like
571 let param_id = tcx.hir().local_def_id_to_hir_id(def_id);
572 let param_owner = tcx.hir().ty_param_owner(param_id);
573 let param_owner_def_id = tcx.hir().local_def_id(param_owner);
574 let generics = tcx.generics_of(param_owner_def_id);
575 let index = generics.param_def_id_to_index[&def_id.to_def_id()];
576 let ty = tcx.mk_ty_param(index, tcx.hir().ty_param_name(param_id));
578 // Don't look for bounds where the type parameter isn't in scope.
579 let parent = if item_def_id == param_owner_def_id.to_def_id() {
582 tcx.generics_of(item_def_id).parent
585 let mut result = parent
587 let icx = ItemCtxt::new(tcx, parent);
588 icx.get_type_parameter_bounds(DUMMY_SP, def_id.to_def_id(), assoc_name)
590 .unwrap_or_default();
591 let mut extend = None;
593 let item_hir_id = tcx.hir().local_def_id_to_hir_id(item_def_id.expect_local());
594 let ast_generics = match tcx.hir().get(item_hir_id) {
595 Node::TraitItem(item) => &item.generics,
597 Node::ImplItem(item) => &item.generics,
599 Node::Item(item) => {
601 ItemKind::Fn(.., ref generics, _)
602 | ItemKind::Impl(hir::Impl { ref generics, .. })
603 | ItemKind::TyAlias(_, ref generics)
604 | ItemKind::OpaqueTy(OpaqueTy {
606 origin: hir::OpaqueTyOrigin::TyAlias,
609 | ItemKind::Enum(_, ref generics)
610 | ItemKind::Struct(_, ref generics)
611 | ItemKind::Union(_, ref generics) => generics,
612 ItemKind::Trait(_, _, ref generics, ..) => {
613 // Implied `Self: Trait` and supertrait bounds.
614 if param_id == item_hir_id {
615 let identity_trait_ref = ty::TraitRef::identity(tcx, item_def_id);
617 Some((identity_trait_ref.without_const().to_predicate(tcx), item.span));
625 Node::ForeignItem(item) => match item.kind {
626 ForeignItemKind::Fn(_, _, ref generics) => generics,
633 let icx = ItemCtxt::new(tcx, item_def_id);
634 let extra_predicates = extend.into_iter().chain(
635 icx.type_parameter_bounds_in_generics(
639 OnlySelfBounds(true),
643 .filter(|(predicate, _)| match predicate.kind().skip_binder() {
644 ty::PredicateKind::Trait(data) => data.self_ty().is_param(index),
649 tcx.arena.alloc_from_iter(result.predicates.iter().copied().chain(extra_predicates));
653 impl<'tcx> ItemCtxt<'tcx> {
654 /// Finds bounds from `hir::Generics`. This requires scanning through the
655 /// AST. We do this to avoid having to convert *all* the bounds, which
656 /// would create artificial cycles. Instead, we can only convert the
657 /// bounds for a type parameter `X` if `X::Foo` is used.
658 fn type_parameter_bounds_in_generics(
660 ast_generics: &'tcx hir::Generics<'tcx>,
661 param_id: hir::HirId,
663 only_self_bounds: OnlySelfBounds,
664 assoc_name: Option<Ident>,
665 ) -> Vec<(ty::Predicate<'tcx>, Span)> {
666 let from_ty_params = ast_generics
669 .filter_map(|param| match param.kind {
670 GenericParamKind::Type { .. } if param.hir_id == param_id => Some(¶m.bounds),
673 .flat_map(|bounds| bounds.iter())
674 .filter(|b| match assoc_name {
675 Some(assoc_name) => self.bound_defines_assoc_item(b, assoc_name),
678 .flat_map(|b| predicates_from_bound(self, ty, b, ty::List::empty()));
680 let param_def_id = self.tcx.hir().local_def_id(param_id).to_def_id();
681 let from_where_clauses = ast_generics
685 .filter_map(|wp| match *wp {
686 hir::WherePredicate::BoundPredicate(ref bp) => Some(bp),
690 let bt = if bp.is_param_bound(param_def_id) {
692 } else if !only_self_bounds.0 {
693 Some(self.to_ty(bp.bounded_ty))
697 let bvars = self.tcx.late_bound_vars(bp.bounded_ty.hir_id);
701 .filter(|b| match assoc_name {
702 Some(assoc_name) => self.bound_defines_assoc_item(b, assoc_name),
705 .filter_map(move |b| bt.map(|bt| (bt, b, bvars)))
707 .flat_map(|(bt, b, bvars)| predicates_from_bound(self, bt, b, bvars));
709 from_ty_params.chain(from_where_clauses).collect()
712 fn bound_defines_assoc_item(&self, b: &hir::GenericBound<'_>, assoc_name: Ident) -> bool {
713 debug!("bound_defines_assoc_item(b={:?}, assoc_name={:?})", b, assoc_name);
716 hir::GenericBound::Trait(poly_trait_ref, _) => {
717 let trait_ref = &poly_trait_ref.trait_ref;
718 if let Some(trait_did) = trait_ref.trait_def_id() {
719 self.tcx.trait_may_define_assoc_type(trait_did, assoc_name)
729 fn convert_item(tcx: TyCtxt<'_>, item_id: hir::ItemId) {
730 let it = tcx.hir().item(item_id);
731 debug!("convert: item {} with id {}", it.ident, it.hir_id());
732 let def_id = item_id.def_id;
735 // These don't define types.
736 hir::ItemKind::ExternCrate(_)
737 | hir::ItemKind::Use(..)
738 | hir::ItemKind::Macro(_)
739 | hir::ItemKind::Mod(_)
740 | hir::ItemKind::GlobalAsm(_) => {}
741 hir::ItemKind::ForeignMod { items, .. } => {
743 let item = tcx.hir().foreign_item(item.id);
744 tcx.ensure().generics_of(item.def_id);
745 tcx.ensure().type_of(item.def_id);
746 tcx.ensure().predicates_of(item.def_id);
748 hir::ForeignItemKind::Fn(..) => tcx.ensure().fn_sig(item.def_id),
749 hir::ForeignItemKind::Static(..) => {
750 let mut visitor = PlaceholderHirTyCollector::default();
751 visitor.visit_foreign_item(item);
752 placeholder_type_error(
766 hir::ItemKind::Enum(ref enum_definition, _) => {
767 tcx.ensure().generics_of(def_id);
768 tcx.ensure().type_of(def_id);
769 tcx.ensure().predicates_of(def_id);
770 convert_enum_variant_types(tcx, def_id.to_def_id(), enum_definition.variants);
772 hir::ItemKind::Impl { .. } => {
773 tcx.ensure().generics_of(def_id);
774 tcx.ensure().type_of(def_id);
775 tcx.ensure().impl_trait_ref(def_id);
776 tcx.ensure().predicates_of(def_id);
778 hir::ItemKind::Trait(..) => {
779 tcx.ensure().generics_of(def_id);
780 tcx.ensure().trait_def(def_id);
781 tcx.at(it.span).super_predicates_of(def_id);
782 tcx.ensure().predicates_of(def_id);
784 hir::ItemKind::TraitAlias(..) => {
785 tcx.ensure().generics_of(def_id);
786 tcx.at(it.span).super_predicates_of(def_id);
787 tcx.ensure().predicates_of(def_id);
789 hir::ItemKind::Struct(ref struct_def, _) | hir::ItemKind::Union(ref struct_def, _) => {
790 tcx.ensure().generics_of(def_id);
791 tcx.ensure().type_of(def_id);
792 tcx.ensure().predicates_of(def_id);
794 for f in struct_def.fields() {
795 let def_id = tcx.hir().local_def_id(f.hir_id);
796 tcx.ensure().generics_of(def_id);
797 tcx.ensure().type_of(def_id);
798 tcx.ensure().predicates_of(def_id);
801 if let Some(ctor_hir_id) = struct_def.ctor_hir_id() {
802 convert_variant_ctor(tcx, ctor_hir_id);
806 // Desugared from `impl Trait`, so visited by the function's return type.
807 hir::ItemKind::OpaqueTy(hir::OpaqueTy {
808 origin: hir::OpaqueTyOrigin::FnReturn(..) | hir::OpaqueTyOrigin::AsyncFn(..),
812 // Don't call `type_of` on opaque types, since that depends on type
813 // checking function bodies. `check_item_type` ensures that it's called
815 hir::ItemKind::OpaqueTy(..) => {
816 tcx.ensure().generics_of(def_id);
817 tcx.ensure().predicates_of(def_id);
818 tcx.ensure().explicit_item_bounds(def_id);
820 hir::ItemKind::TyAlias(..)
821 | hir::ItemKind::Static(..)
822 | hir::ItemKind::Const(..)
823 | hir::ItemKind::Fn(..) => {
824 tcx.ensure().generics_of(def_id);
825 tcx.ensure().type_of(def_id);
826 tcx.ensure().predicates_of(def_id);
828 hir::ItemKind::Fn(..) => tcx.ensure().fn_sig(def_id),
829 hir::ItemKind::OpaqueTy(..) => tcx.ensure().item_bounds(def_id),
830 hir::ItemKind::Const(ty, ..) | hir::ItemKind::Static(ty, ..) => {
831 // (#75889): Account for `const C: dyn Fn() -> _ = "";`
832 if let hir::TyKind::TraitObject(..) = ty.kind {
833 let mut visitor = PlaceholderHirTyCollector::default();
834 visitor.visit_item(it);
835 placeholder_type_error(
852 fn convert_trait_item(tcx: TyCtxt<'_>, trait_item_id: hir::TraitItemId) {
853 let trait_item = tcx.hir().trait_item(trait_item_id);
854 tcx.ensure().generics_of(trait_item_id.def_id);
856 match trait_item.kind {
857 hir::TraitItemKind::Fn(..) => {
858 tcx.ensure().type_of(trait_item_id.def_id);
859 tcx.ensure().fn_sig(trait_item_id.def_id);
862 hir::TraitItemKind::Const(.., Some(_)) => {
863 tcx.ensure().type_of(trait_item_id.def_id);
866 hir::TraitItemKind::Const(..) => {
867 tcx.ensure().type_of(trait_item_id.def_id);
868 // Account for `const C: _;`.
869 let mut visitor = PlaceholderHirTyCollector::default();
870 visitor.visit_trait_item(trait_item);
871 placeholder_type_error(tcx, None, &[], visitor.0, false, None, "constant");
874 hir::TraitItemKind::Type(_, Some(_)) => {
875 tcx.ensure().item_bounds(trait_item_id.def_id);
876 tcx.ensure().type_of(trait_item_id.def_id);
877 // Account for `type T = _;`.
878 let mut visitor = PlaceholderHirTyCollector::default();
879 visitor.visit_trait_item(trait_item);
880 placeholder_type_error(tcx, None, &[], visitor.0, false, None, "associated type");
883 hir::TraitItemKind::Type(_, None) => {
884 tcx.ensure().item_bounds(trait_item_id.def_id);
885 // #74612: Visit and try to find bad placeholders
886 // even if there is no concrete type.
887 let mut visitor = PlaceholderHirTyCollector::default();
888 visitor.visit_trait_item(trait_item);
890 placeholder_type_error(tcx, None, &[], visitor.0, false, None, "associated type");
894 tcx.ensure().predicates_of(trait_item_id.def_id);
897 fn convert_impl_item(tcx: TyCtxt<'_>, impl_item_id: hir::ImplItemId) {
898 let def_id = impl_item_id.def_id;
899 tcx.ensure().generics_of(def_id);
900 tcx.ensure().type_of(def_id);
901 tcx.ensure().predicates_of(def_id);
902 let impl_item = tcx.hir().impl_item(impl_item_id);
903 match impl_item.kind {
904 hir::ImplItemKind::Fn(..) => {
905 tcx.ensure().fn_sig(def_id);
907 hir::ImplItemKind::TyAlias(_) => {
908 // Account for `type T = _;`
909 let mut visitor = PlaceholderHirTyCollector::default();
910 visitor.visit_impl_item(impl_item);
912 placeholder_type_error(tcx, None, &[], visitor.0, false, None, "associated type");
914 hir::ImplItemKind::Const(..) => {}
918 fn convert_variant_ctor(tcx: TyCtxt<'_>, ctor_id: hir::HirId) {
919 let def_id = tcx.hir().local_def_id(ctor_id);
920 tcx.ensure().generics_of(def_id);
921 tcx.ensure().type_of(def_id);
922 tcx.ensure().predicates_of(def_id);
925 fn convert_enum_variant_types(tcx: TyCtxt<'_>, def_id: DefId, variants: &[hir::Variant<'_>]) {
926 let def = tcx.adt_def(def_id);
927 let repr_type = def.repr.discr_type();
928 let initial = repr_type.initial_discriminant(tcx);
929 let mut prev_discr = None::<Discr<'_>>;
931 // fill the discriminant values and field types
932 for variant in variants {
933 let wrapped_discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
935 if let Some(ref e) = variant.disr_expr {
936 let expr_did = tcx.hir().local_def_id(e.hir_id);
937 def.eval_explicit_discr(tcx, expr_did.to_def_id())
938 } else if let Some(discr) = repr_type.disr_incr(tcx, prev_discr) {
941 struct_span_err!(tcx.sess, variant.span, E0370, "enum discriminant overflowed")
944 format!("overflowed on value after {}", prev_discr.unwrap()),
947 "explicitly set `{} = {}` if that is desired outcome",
948 variant.ident, wrapped_discr
953 .unwrap_or(wrapped_discr),
956 for f in variant.data.fields() {
957 let def_id = tcx.hir().local_def_id(f.hir_id);
958 tcx.ensure().generics_of(def_id);
959 tcx.ensure().type_of(def_id);
960 tcx.ensure().predicates_of(def_id);
963 // Convert the ctor, if any. This also registers the variant as
965 if let Some(ctor_hir_id) = variant.data.ctor_hir_id() {
966 convert_variant_ctor(tcx, ctor_hir_id);
973 variant_did: Option<LocalDefId>,
974 ctor_did: Option<LocalDefId>,
976 discr: ty::VariantDiscr,
977 def: &hir::VariantData<'_>,
978 adt_kind: ty::AdtKind,
979 parent_did: LocalDefId,
980 ) -> ty::VariantDef {
981 let mut seen_fields: FxHashMap<Ident, Span> = Default::default();
986 let fid = tcx.hir().local_def_id(f.hir_id);
987 let dup_span = seen_fields.get(&f.ident.normalize_to_macros_2_0()).cloned();
988 if let Some(prev_span) = dup_span {
989 tcx.sess.emit_err(errors::FieldAlreadyDeclared {
995 seen_fields.insert(f.ident.normalize_to_macros_2_0(), f.span);
998 ty::FieldDef { did: fid.to_def_id(), ident: f.ident, vis: tcx.visibility(fid) }
1001 let recovered = match def {
1002 hir::VariantData::Struct(_, r) => *r,
1005 ty::VariantDef::new(
1007 variant_did.map(LocalDefId::to_def_id),
1008 ctor_did.map(LocalDefId::to_def_id),
1011 CtorKind::from_hir(def),
1013 parent_did.to_def_id(),
1015 adt_kind == AdtKind::Struct && tcx.has_attr(parent_did.to_def_id(), sym::non_exhaustive)
1016 || variant_did.map_or(false, |variant_did| {
1017 tcx.has_attr(variant_did.to_def_id(), sym::non_exhaustive)
1022 fn adt_def(tcx: TyCtxt<'_>, def_id: DefId) -> &ty::AdtDef {
1025 let def_id = def_id.expect_local();
1026 let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
1027 let item = match tcx.hir().get(hir_id) {
1028 Node::Item(item) => item,
1032 let repr = ReprOptions::new(tcx, def_id.to_def_id());
1033 let (kind, variants) = match item.kind {
1034 ItemKind::Enum(ref def, _) => {
1035 let mut distance_from_explicit = 0;
1040 let variant_did = Some(tcx.hir().local_def_id(v.id));
1042 v.data.ctor_hir_id().map(|hir_id| tcx.hir().local_def_id(hir_id));
1044 let discr = if let Some(ref e) = v.disr_expr {
1045 distance_from_explicit = 0;
1046 ty::VariantDiscr::Explicit(tcx.hir().local_def_id(e.hir_id).to_def_id())
1048 ty::VariantDiscr::Relative(distance_from_explicit)
1050 distance_from_explicit += 1;
1065 (AdtKind::Enum, variants)
1067 ItemKind::Struct(ref def, _) => {
1068 let variant_did = None::<LocalDefId>;
1069 let ctor_did = def.ctor_hir_id().map(|hir_id| tcx.hir().local_def_id(hir_id));
1071 let variants = std::iter::once(convert_variant(
1076 ty::VariantDiscr::Relative(0),
1083 (AdtKind::Struct, variants)
1085 ItemKind::Union(ref def, _) => {
1086 let variant_did = None;
1087 let ctor_did = def.ctor_hir_id().map(|hir_id| tcx.hir().local_def_id(hir_id));
1089 let variants = std::iter::once(convert_variant(
1094 ty::VariantDiscr::Relative(0),
1101 (AdtKind::Union, variants)
1105 tcx.alloc_adt_def(def_id.to_def_id(), kind, variants, repr)
1108 /// Ensures that the super-predicates of the trait with a `DefId`
1109 /// of `trait_def_id` are converted and stored. This also ensures that
1110 /// the transitive super-predicates are converted.
1111 fn super_predicates_of(tcx: TyCtxt<'_>, trait_def_id: DefId) -> ty::GenericPredicates<'_> {
1112 debug!("super_predicates(trait_def_id={:?})", trait_def_id);
1113 tcx.super_predicates_that_define_assoc_type((trait_def_id, None))
1116 /// Ensures that the super-predicates of the trait with a `DefId`
1117 /// of `trait_def_id` are converted and stored. This also ensures that
1118 /// the transitive super-predicates are converted.
1119 fn super_predicates_that_define_assoc_type(
1121 (trait_def_id, assoc_name): (DefId, Option<Ident>),
1122 ) -> ty::GenericPredicates<'_> {
1124 "super_predicates_that_define_assoc_type(trait_def_id={:?}, assoc_name={:?})",
1125 trait_def_id, assoc_name
1127 if trait_def_id.is_local() {
1128 debug!("super_predicates_that_define_assoc_type: local trait_def_id={:?}", trait_def_id);
1129 let trait_hir_id = tcx.hir().local_def_id_to_hir_id(trait_def_id.expect_local());
1131 let item = match tcx.hir().get(trait_hir_id) {
1132 Node::Item(item) => item,
1133 _ => bug!("trait_node_id {} is not an item", trait_hir_id),
1136 let (generics, bounds) = match item.kind {
1137 hir::ItemKind::Trait(.., ref generics, ref supertraits, _) => (generics, supertraits),
1138 hir::ItemKind::TraitAlias(ref generics, ref supertraits) => (generics, supertraits),
1139 _ => span_bug!(item.span, "super_predicates invoked on non-trait"),
1142 let icx = ItemCtxt::new(tcx, trait_def_id);
1144 // Convert the bounds that follow the colon, e.g., `Bar + Zed` in `trait Foo: Bar + Zed`.
1145 let self_param_ty = tcx.types.self_param;
1146 let superbounds1 = if let Some(assoc_name) = assoc_name {
1147 <dyn AstConv<'_>>::compute_bounds_that_match_assoc_type(
1154 <dyn AstConv<'_>>::compute_bounds(&icx, self_param_ty, bounds)
1157 let superbounds1 = superbounds1.predicates(tcx, self_param_ty);
1159 // Convert any explicit superbounds in the where-clause,
1160 // e.g., `trait Foo where Self: Bar`.
1161 // In the case of trait aliases, however, we include all bounds in the where-clause,
1162 // so e.g., `trait Foo = where u32: PartialEq<Self>` would include `u32: PartialEq<Self>`
1163 // as one of its "superpredicates".
1164 let is_trait_alias = tcx.is_trait_alias(trait_def_id);
1165 let superbounds2 = icx.type_parameter_bounds_in_generics(
1169 OnlySelfBounds(!is_trait_alias),
1173 // Combine the two lists to form the complete set of superbounds:
1174 let superbounds = &*tcx.arena.alloc_from_iter(superbounds1.into_iter().chain(superbounds2));
1176 // Now require that immediate supertraits are converted,
1177 // which will, in turn, reach indirect supertraits.
1178 if assoc_name.is_none() {
1179 // Now require that immediate supertraits are converted,
1180 // which will, in turn, reach indirect supertraits.
1181 for &(pred, span) in superbounds {
1182 debug!("superbound: {:?}", pred);
1183 if let ty::PredicateKind::Trait(bound) = pred.kind().skip_binder() {
1184 tcx.at(span).super_predicates_of(bound.def_id());
1189 ty::GenericPredicates { parent: None, predicates: superbounds }
1191 // if `assoc_name` is None, then the query should've been redirected to an
1192 // external provider
1193 assert!(assoc_name.is_some());
1194 tcx.super_predicates_of(trait_def_id)
1198 fn trait_def(tcx: TyCtxt<'_>, def_id: DefId) -> ty::TraitDef {
1199 let item = tcx.hir().expect_item(def_id.expect_local());
1201 let (is_auto, unsafety) = match item.kind {
1202 hir::ItemKind::Trait(is_auto, unsafety, ..) => (is_auto == hir::IsAuto::Yes, unsafety),
1203 hir::ItemKind::TraitAlias(..) => (false, hir::Unsafety::Normal),
1204 _ => span_bug!(item.span, "trait_def_of_item invoked on non-trait"),
1207 let paren_sugar = tcx.has_attr(def_id, sym::rustc_paren_sugar);
1208 if paren_sugar && !tcx.features().unboxed_closures {
1212 "the `#[rustc_paren_sugar]` attribute is a temporary means of controlling \
1213 which traits can use parenthetical notation",
1215 .help("add `#![feature(unboxed_closures)]` to the crate attributes to use it")
1219 let is_marker = tcx.has_attr(def_id, sym::marker);
1220 let skip_array_during_method_dispatch =
1221 tcx.has_attr(def_id, sym::rustc_skip_array_during_method_dispatch);
1222 let spec_kind = if tcx.has_attr(def_id, sym::rustc_unsafe_specialization_marker) {
1223 ty::trait_def::TraitSpecializationKind::Marker
1224 } else if tcx.has_attr(def_id, sym::rustc_specialization_trait) {
1225 ty::trait_def::TraitSpecializationKind::AlwaysApplicable
1227 ty::trait_def::TraitSpecializationKind::None
1229 let def_path_hash = tcx.def_path_hash(def_id);
1236 skip_array_during_method_dispatch,
1242 fn has_late_bound_regions<'tcx>(tcx: TyCtxt<'tcx>, node: Node<'tcx>) -> Option<Span> {
1243 struct LateBoundRegionsDetector<'tcx> {
1245 outer_index: ty::DebruijnIndex,
1246 has_late_bound_regions: Option<Span>,
1249 impl<'tcx> Visitor<'tcx> for LateBoundRegionsDetector<'tcx> {
1250 type Map = intravisit::ErasedMap<'tcx>;
1252 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
1253 NestedVisitorMap::None
1256 fn visit_ty(&mut self, ty: &'tcx hir::Ty<'tcx>) {
1257 if self.has_late_bound_regions.is_some() {
1261 hir::TyKind::BareFn(..) => {
1262 self.outer_index.shift_in(1);
1263 intravisit::walk_ty(self, ty);
1264 self.outer_index.shift_out(1);
1266 _ => intravisit::walk_ty(self, ty),
1270 fn visit_poly_trait_ref(
1272 tr: &'tcx hir::PolyTraitRef<'tcx>,
1273 m: hir::TraitBoundModifier,
1275 if self.has_late_bound_regions.is_some() {
1278 self.outer_index.shift_in(1);
1279 intravisit::walk_poly_trait_ref(self, tr, m);
1280 self.outer_index.shift_out(1);
1283 fn visit_lifetime(&mut self, lt: &'tcx hir::Lifetime) {
1284 if self.has_late_bound_regions.is_some() {
1288 match self.tcx.named_region(lt.hir_id) {
1289 Some(rl::Region::Static | rl::Region::EarlyBound(..)) => {}
1291 rl::Region::LateBound(debruijn, _, _, _)
1292 | rl::Region::LateBoundAnon(debruijn, _, _),
1293 ) if debruijn < self.outer_index => {}
1295 rl::Region::LateBound(..)
1296 | rl::Region::LateBoundAnon(..)
1297 | rl::Region::Free(..),
1300 self.has_late_bound_regions = Some(lt.span);
1306 fn has_late_bound_regions<'tcx>(
1308 generics: &'tcx hir::Generics<'tcx>,
1309 decl: &'tcx hir::FnDecl<'tcx>,
1311 let mut visitor = LateBoundRegionsDetector {
1313 outer_index: ty::INNERMOST,
1314 has_late_bound_regions: None,
1316 for param in generics.params {
1317 if let GenericParamKind::Lifetime { .. } = param.kind {
1318 if tcx.is_late_bound(param.hir_id) {
1319 return Some(param.span);
1323 visitor.visit_fn_decl(decl);
1324 visitor.has_late_bound_regions
1328 Node::TraitItem(item) => match item.kind {
1329 hir::TraitItemKind::Fn(ref sig, _) => {
1330 has_late_bound_regions(tcx, &item.generics, sig.decl)
1334 Node::ImplItem(item) => match item.kind {
1335 hir::ImplItemKind::Fn(ref sig, _) => {
1336 has_late_bound_regions(tcx, &item.generics, sig.decl)
1340 Node::ForeignItem(item) => match item.kind {
1341 hir::ForeignItemKind::Fn(fn_decl, _, ref generics) => {
1342 has_late_bound_regions(tcx, generics, fn_decl)
1346 Node::Item(item) => match item.kind {
1347 hir::ItemKind::Fn(ref sig, .., ref generics, _) => {
1348 has_late_bound_regions(tcx, generics, sig.decl)
1356 struct AnonConstInParamTyDetector {
1358 found_anon_const_in_param_ty: bool,
1362 impl<'v> Visitor<'v> for AnonConstInParamTyDetector {
1363 type Map = intravisit::ErasedMap<'v>;
1365 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
1366 NestedVisitorMap::None
1369 fn visit_generic_param(&mut self, p: &'v hir::GenericParam<'v>) {
1370 if let GenericParamKind::Const { ty, default: _ } = p.kind {
1371 let prev = self.in_param_ty;
1372 self.in_param_ty = true;
1374 self.in_param_ty = prev;
1378 fn visit_anon_const(&mut self, c: &'v hir::AnonConst) {
1379 if self.in_param_ty && self.ct == c.hir_id {
1380 self.found_anon_const_in_param_ty = true;
1382 intravisit::walk_anon_const(self, c)
1387 fn generics_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::Generics {
1390 let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
1392 let node = tcx.hir().get(hir_id);
1393 let parent_def_id = match node {
1395 | Node::TraitItem(_)
1398 | Node::Field(_) => {
1399 let parent_id = tcx.hir().get_parent_item(hir_id);
1400 Some(tcx.hir().local_def_id(parent_id).to_def_id())
1402 // FIXME(#43408) always enable this once `lazy_normalization` is
1403 // stable enough and does not need a feature gate anymore.
1404 Node::AnonConst(_) => {
1405 let parent_id = tcx.hir().get_parent_item(hir_id);
1406 let parent_def_id = tcx.hir().local_def_id(parent_id);
1408 let mut in_param_ty = false;
1409 for (_parent, node) in tcx.hir().parent_iter(hir_id) {
1410 if let Some(generics) = node.generics() {
1411 let mut visitor = AnonConstInParamTyDetector {
1413 found_anon_const_in_param_ty: false,
1417 visitor.visit_generics(generics);
1418 in_param_ty = visitor.found_anon_const_in_param_ty;
1424 // We do not allow generic parameters in anon consts if we are inside
1425 // of a const parameter type, e.g. `struct Foo<const N: usize, const M: [u8; N]>` is not allowed.
1427 } else if tcx.lazy_normalization() {
1428 if let Some(param_id) = tcx.hir().opt_const_param_default_param_hir_id(hir_id) {
1429 // If the def_id we are calling generics_of on is an anon ct default i.e:
1431 // struct Foo<const N: usize = { .. }>;
1432 // ^^^ ^ ^^^^^^ def id of this anon const
1436 // then we only want to return generics for params to the left of `N`. If we don't do that we
1437 // end up with that const looking like: `ty::ConstKind::Unevaluated(def_id, substs: [N#0])`.
1439 // This causes ICEs (#86580) when building the substs for Foo in `fn foo() -> Foo { .. }` as
1440 // we substitute the defaults with the partially built substs when we build the substs. Subst'ing
1441 // the `N#0` on the unevaluated const indexes into the empty substs we're in the process of building.
1443 // We fix this by having this function return the parent's generics ourselves and truncating the
1444 // generics to only include non-forward declared params (with the exception of the `Self` ty)
1446 // For the above code example that means we want `substs: []`
1447 // For the following struct def we want `substs: [N#0]` when generics_of is called on
1448 // the def id of the `{ N + 1 }` anon const
1449 // struct Foo<const N: usize, const M: usize = { N + 1 }>;
1451 // This has some implications for how we get the predicates available to the anon const
1452 // see `explicit_predicates_of` for more information on this
1453 let generics = tcx.generics_of(parent_def_id.to_def_id());
1454 let param_def = tcx.hir().local_def_id(param_id).to_def_id();
1455 let param_def_idx = generics.param_def_id_to_index[¶m_def];
1456 // In the above example this would be .params[..N#0]
1457 let params = generics.params[..param_def_idx as usize].to_owned();
1458 let param_def_id_to_index =
1459 params.iter().map(|param| (param.def_id, param.index)).collect();
1461 return ty::Generics {
1462 // we set the parent of these generics to be our parent's parent so that we
1463 // dont end up with substs: [N, M, N] for the const default on a struct like this:
1464 // struct Foo<const N: usize, const M: usize = { ... }>;
1465 parent: generics.parent,
1466 parent_count: generics.parent_count,
1468 param_def_id_to_index,
1469 has_self: generics.has_self,
1470 has_late_bound_regions: generics.has_late_bound_regions,
1474 // HACK(eddyb) this provides the correct generics when
1475 // `feature(generic_const_expressions)` is enabled, so that const expressions
1476 // used with const generics, e.g. `Foo<{N+1}>`, can work at all.
1478 // Note that we do not supply the parent generics when using
1479 // `min_const_generics`.
1480 Some(parent_def_id.to_def_id())
1482 let parent_node = tcx.hir().get(tcx.hir().get_parent_node(hir_id));
1484 // HACK(eddyb) this provides the correct generics for repeat
1485 // expressions' count (i.e. `N` in `[x; N]`), and explicit
1486 // `enum` discriminants (i.e. `D` in `enum Foo { Bar = D }`),
1487 // as they shouldn't be able to cause query cycle errors.
1488 Node::Expr(&Expr { kind: ExprKind::Repeat(_, ref constant), .. })
1489 if constant.hir_id() == hir_id =>
1491 Some(parent_def_id.to_def_id())
1493 Node::Variant(Variant { disr_expr: Some(ref constant), .. })
1494 if constant.hir_id == hir_id =>
1496 Some(parent_def_id.to_def_id())
1498 Node::Expr(&Expr { kind: ExprKind::ConstBlock(_), .. }) => {
1499 Some(tcx.typeck_root_def_id(def_id))
1505 Node::Expr(&hir::Expr { kind: hir::ExprKind::Closure(..), .. }) => {
1506 Some(tcx.typeck_root_def_id(def_id))
1508 Node::Item(item) => match item.kind {
1509 ItemKind::OpaqueTy(hir::OpaqueTy {
1511 hir::OpaqueTyOrigin::FnReturn(fn_def_id) | hir::OpaqueTyOrigin::AsyncFn(fn_def_id),
1513 }) => Some(fn_def_id.to_def_id()),
1514 ItemKind::OpaqueTy(hir::OpaqueTy { origin: hir::OpaqueTyOrigin::TyAlias, .. }) => {
1515 let parent_id = tcx.hir().get_parent_item(hir_id);
1516 assert!(parent_id != hir_id && parent_id != CRATE_HIR_ID);
1517 debug!("generics_of: parent of opaque ty {:?} is {:?}", def_id, parent_id);
1518 // Opaque types are always nested within another item, and
1519 // inherit the generics of the item.
1520 Some(tcx.hir().local_def_id(parent_id).to_def_id())
1527 let mut opt_self = None;
1528 let mut allow_defaults = false;
1530 let no_generics = hir::Generics::empty();
1531 let ast_generics = match node {
1532 Node::TraitItem(item) => &item.generics,
1534 Node::ImplItem(item) => &item.generics,
1536 Node::Item(item) => {
1538 ItemKind::Fn(.., ref generics, _)
1539 | ItemKind::Impl(hir::Impl { ref generics, .. }) => generics,
1541 ItemKind::TyAlias(_, ref generics)
1542 | ItemKind::Enum(_, ref generics)
1543 | ItemKind::Struct(_, ref generics)
1544 | ItemKind::OpaqueTy(hir::OpaqueTy { ref generics, .. })
1545 | ItemKind::Union(_, ref generics) => {
1546 allow_defaults = true;
1550 ItemKind::Trait(_, _, ref generics, ..)
1551 | ItemKind::TraitAlias(ref generics, ..) => {
1552 // Add in the self type parameter.
1554 // Something of a hack: use the node id for the trait, also as
1555 // the node id for the Self type parameter.
1556 let param_id = item.def_id;
1558 opt_self = Some(ty::GenericParamDef {
1560 name: kw::SelfUpper,
1561 def_id: param_id.to_def_id(),
1562 pure_wrt_drop: false,
1563 kind: ty::GenericParamDefKind::Type {
1565 object_lifetime_default: rl::Set1::Empty,
1570 allow_defaults = true;
1578 Node::ForeignItem(item) => match item.kind {
1579 ForeignItemKind::Static(..) => &no_generics,
1580 ForeignItemKind::Fn(_, _, ref generics) => generics,
1581 ForeignItemKind::Type => &no_generics,
1587 let has_self = opt_self.is_some();
1588 let mut parent_has_self = false;
1589 let mut own_start = has_self as u32;
1590 let parent_count = parent_def_id.map_or(0, |def_id| {
1591 let generics = tcx.generics_of(def_id);
1593 parent_has_self = generics.has_self;
1594 own_start = generics.count() as u32;
1595 generics.parent_count + generics.params.len()
1598 let mut params: Vec<_> = Vec::with_capacity(ast_generics.params.len() + has_self as usize);
1600 if let Some(opt_self) = opt_self {
1601 params.push(opt_self);
1604 let early_lifetimes = early_bound_lifetimes_from_generics(tcx, ast_generics);
1605 params.extend(early_lifetimes.enumerate().map(|(i, param)| ty::GenericParamDef {
1606 name: param.name.ident().name,
1607 index: own_start + i as u32,
1608 def_id: tcx.hir().local_def_id(param.hir_id).to_def_id(),
1609 pure_wrt_drop: param.pure_wrt_drop,
1610 kind: ty::GenericParamDefKind::Lifetime,
1613 let object_lifetime_defaults = tcx.object_lifetime_defaults(hir_id);
1615 // Now create the real type and const parameters.
1616 let type_start = own_start - has_self as u32 + params.len() as u32;
1619 params.extend(ast_generics.params.iter().filter_map(|param| match param.kind {
1620 GenericParamKind::Lifetime { .. } => None,
1621 GenericParamKind::Type { ref default, synthetic, .. } => {
1622 if !allow_defaults && default.is_some() {
1623 if !tcx.features().default_type_parameter_fallback {
1624 tcx.struct_span_lint_hir(
1625 lint::builtin::INVALID_TYPE_PARAM_DEFAULT,
1630 "defaults for type parameters are only allowed in \
1631 `struct`, `enum`, `type`, or `trait` definitions",
1639 let kind = ty::GenericParamDefKind::Type {
1640 has_default: default.is_some(),
1641 object_lifetime_default: object_lifetime_defaults
1643 .map_or(rl::Set1::Empty, |o| o[i]),
1647 let param_def = ty::GenericParamDef {
1648 index: type_start + i as u32,
1649 name: param.name.ident().name,
1650 def_id: tcx.hir().local_def_id(param.hir_id).to_def_id(),
1651 pure_wrt_drop: param.pure_wrt_drop,
1657 GenericParamKind::Const { default, .. } => {
1658 if !allow_defaults && default.is_some() {
1661 "defaults for const parameters are only allowed in \
1662 `struct`, `enum`, `type`, or `trait` definitions",
1666 let param_def = ty::GenericParamDef {
1667 index: type_start + i as u32,
1668 name: param.name.ident().name,
1669 def_id: tcx.hir().local_def_id(param.hir_id).to_def_id(),
1670 pure_wrt_drop: param.pure_wrt_drop,
1671 kind: ty::GenericParamDefKind::Const { has_default: default.is_some() },
1678 // provide junk type parameter defs - the only place that
1679 // cares about anything but the length is instantiation,
1680 // and we don't do that for closures.
1681 if let Node::Expr(&hir::Expr { kind: hir::ExprKind::Closure(.., gen), .. }) = node {
1682 let dummy_args = if gen.is_some() {
1683 &["<resume_ty>", "<yield_ty>", "<return_ty>", "<witness>", "<upvars>"][..]
1685 &["<closure_kind>", "<closure_signature>", "<upvars>"][..]
1688 params.extend(dummy_args.iter().enumerate().map(|(i, &arg)| ty::GenericParamDef {
1689 index: type_start + i as u32,
1690 name: Symbol::intern(arg),
1692 pure_wrt_drop: false,
1693 kind: ty::GenericParamDefKind::Type {
1695 object_lifetime_default: rl::Set1::Empty,
1701 // provide junk type parameter defs for const blocks.
1702 if let Node::AnonConst(_) = node {
1703 let parent_node = tcx.hir().get(tcx.hir().get_parent_node(hir_id));
1704 if let Node::Expr(&Expr { kind: ExprKind::ConstBlock(_), .. }) = parent_node {
1705 params.push(ty::GenericParamDef {
1707 name: Symbol::intern("<const_ty>"),
1709 pure_wrt_drop: false,
1710 kind: ty::GenericParamDefKind::Type {
1712 object_lifetime_default: rl::Set1::Empty,
1719 let param_def_id_to_index = params.iter().map(|param| (param.def_id, param.index)).collect();
1722 parent: parent_def_id,
1725 param_def_id_to_index,
1726 has_self: has_self || parent_has_self,
1727 has_late_bound_regions: has_late_bound_regions(tcx, node),
1731 fn are_suggestable_generic_args(generic_args: &[hir::GenericArg<'_>]) -> bool {
1732 generic_args.iter().any(|arg| match arg {
1733 hir::GenericArg::Type(ty) => is_suggestable_infer_ty(ty),
1734 hir::GenericArg::Infer(_) => true,
1739 /// Whether `ty` is a type with `_` placeholders that can be inferred. Used in diagnostics only to
1740 /// use inference to provide suggestions for the appropriate type if possible.
1741 fn is_suggestable_infer_ty(ty: &hir::Ty<'_>) -> bool {
1745 Slice(ty) | Array(ty, _) => is_suggestable_infer_ty(ty),
1746 Tup(tys) => tys.iter().any(is_suggestable_infer_ty),
1747 Ptr(mut_ty) | Rptr(_, mut_ty) => is_suggestable_infer_ty(mut_ty.ty),
1748 OpaqueDef(_, generic_args) => are_suggestable_generic_args(generic_args),
1749 Path(hir::QPath::TypeRelative(ty, segment)) => {
1750 is_suggestable_infer_ty(ty) || are_suggestable_generic_args(segment.args().args)
1752 Path(hir::QPath::Resolved(ty_opt, hir::Path { segments, .. })) => {
1753 ty_opt.map_or(false, is_suggestable_infer_ty)
1754 || segments.iter().any(|segment| are_suggestable_generic_args(segment.args().args))
1760 pub fn get_infer_ret_ty<'hir>(output: &'hir hir::FnRetTy<'hir>) -> Option<&'hir hir::Ty<'hir>> {
1761 if let hir::FnRetTy::Return(ty) = output {
1762 if is_suggestable_infer_ty(ty) {
1769 fn fn_sig(tcx: TyCtxt<'_>, def_id: DefId) -> ty::PolyFnSig<'_> {
1770 use rustc_hir::Node::*;
1773 let def_id = def_id.expect_local();
1774 let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
1776 let icx = ItemCtxt::new(tcx, def_id.to_def_id());
1778 match tcx.hir().get(hir_id) {
1779 TraitItem(hir::TraitItem {
1780 kind: TraitItemKind::Fn(sig, TraitFn::Provided(_)),
1785 | ImplItem(hir::ImplItem { kind: ImplItemKind::Fn(sig, _), ident, generics, .. })
1786 | Item(hir::Item { kind: ItemKind::Fn(sig, generics, _), ident, .. }) => {
1787 match get_infer_ret_ty(&sig.decl.output) {
1789 let fn_sig = tcx.typeck(def_id).liberated_fn_sigs()[hir_id];
1790 // Typeck doesn't expect erased regions to be returned from `type_of`.
1791 let fn_sig = tcx.fold_regions(fn_sig, &mut false, |r, _| match r {
1792 ty::ReErased => tcx.lifetimes.re_static,
1795 let fn_sig = ty::Binder::dummy(fn_sig);
1797 let mut visitor = PlaceholderHirTyCollector::default();
1798 visitor.visit_ty(ty);
1799 let mut diag = bad_placeholder(tcx, "type", visitor.0, "return type");
1800 let ret_ty = fn_sig.skip_binder().output();
1801 if !ret_ty.references_error() {
1802 if !ret_ty.is_closure() {
1803 let ret_ty_str = match ret_ty.kind() {
1804 // Suggest a function pointer return type instead of a unique function definition
1805 // (e.g. `fn() -> i32` instead of `fn() -> i32 { f }`, the latter of which is invalid
1807 ty::FnDef(..) => ret_ty.fn_sig(tcx).to_string(),
1808 _ => ret_ty.to_string(),
1810 diag.span_suggestion(
1812 "replace with the correct return type",
1814 Applicability::MaybeIncorrect,
1817 // We're dealing with a closure, so we should suggest using `impl Fn` or trait bounds
1818 // to prevent the user from getting a papercut while trying to use the unique closure
1819 // syntax (e.g. `[closure@src/lib.rs:2:5: 2:9]`).
1820 diag.help("consider using an `Fn`, `FnMut`, or `FnOnce` trait bound");
1821 diag.note("for more information on `Fn` traits and closure types, see https://doc.rust-lang.org/book/ch13-01-closures.html");
1828 None => <dyn AstConv<'_>>::ty_of_fn(
1831 sig.header.unsafety,
1841 TraitItem(hir::TraitItem {
1842 kind: TraitItemKind::Fn(FnSig { header, decl, span: _ }, _),
1846 }) => <dyn AstConv<'_>>::ty_of_fn(
1857 ForeignItem(&hir::ForeignItem {
1858 kind: ForeignItemKind::Fn(fn_decl, _, _), ident, ..
1860 let abi = tcx.hir().get_foreign_abi(hir_id);
1861 compute_sig_of_foreign_fn_decl(tcx, def_id.to_def_id(), fn_decl, abi, ident)
1864 Ctor(data) | Variant(hir::Variant { data, .. }) if data.ctor_hir_id().is_some() => {
1865 let ty = tcx.type_of(tcx.hir().get_parent_did(hir_id).to_def_id());
1867 data.fields().iter().map(|f| tcx.type_of(tcx.hir().local_def_id(f.hir_id)));
1868 ty::Binder::dummy(tcx.mk_fn_sig(
1872 hir::Unsafety::Normal,
1877 Expr(&hir::Expr { kind: hir::ExprKind::Closure(..), .. }) => {
1878 // Closure signatures are not like other function
1879 // signatures and cannot be accessed through `fn_sig`. For
1880 // example, a closure signature excludes the `self`
1881 // argument. In any case they are embedded within the
1882 // closure type as part of the `ClosureSubsts`.
1884 // To get the signature of a closure, you should use the
1885 // `sig` method on the `ClosureSubsts`:
1887 // substs.as_closure().sig(def_id, tcx)
1889 "to get the signature of a closure, use `substs.as_closure().sig()` not `fn_sig()`",
1894 bug!("unexpected sort of node in fn_sig(): {:?}", x);
1899 fn impl_trait_ref(tcx: TyCtxt<'_>, def_id: DefId) -> Option<ty::TraitRef<'_>> {
1900 let icx = ItemCtxt::new(tcx, def_id);
1901 match tcx.hir().expect_item(def_id.expect_local()).kind {
1902 hir::ItemKind::Impl(ref impl_) => impl_.of_trait.as_ref().map(|ast_trait_ref| {
1903 let selfty = tcx.type_of(def_id);
1904 <dyn AstConv<'_>>::instantiate_mono_trait_ref(&icx, ast_trait_ref, selfty)
1910 fn impl_polarity(tcx: TyCtxt<'_>, def_id: DefId) -> ty::ImplPolarity {
1911 let is_rustc_reservation = tcx.has_attr(def_id, sym::rustc_reservation_impl);
1912 let item = tcx.hir().expect_item(def_id.expect_local());
1914 hir::ItemKind::Impl(hir::Impl {
1915 polarity: hir::ImplPolarity::Negative(span),
1919 if is_rustc_reservation {
1920 let span = span.to(of_trait.as_ref().map_or(*span, |t| t.path.span));
1921 tcx.sess.span_err(span, "reservation impls can't be negative");
1923 ty::ImplPolarity::Negative
1925 hir::ItemKind::Impl(hir::Impl {
1926 polarity: hir::ImplPolarity::Positive,
1930 if is_rustc_reservation {
1931 tcx.sess.span_err(item.span, "reservation impls can't be inherent");
1933 ty::ImplPolarity::Positive
1935 hir::ItemKind::Impl(hir::Impl {
1936 polarity: hir::ImplPolarity::Positive,
1940 if is_rustc_reservation {
1941 ty::ImplPolarity::Reservation
1943 ty::ImplPolarity::Positive
1946 item => bug!("impl_polarity: {:?} not an impl", item),
1950 /// Returns the early-bound lifetimes declared in this generics
1951 /// listing. For anything other than fns/methods, this is just all
1952 /// the lifetimes that are declared. For fns or methods, we have to
1953 /// screen out those that do not appear in any where-clauses etc using
1954 /// `resolve_lifetime::early_bound_lifetimes`.
1955 fn early_bound_lifetimes_from_generics<'a, 'tcx: 'a>(
1957 generics: &'a hir::Generics<'a>,
1958 ) -> impl Iterator<Item = &'a hir::GenericParam<'a>> + Captures<'tcx> {
1959 generics.params.iter().filter(move |param| match param.kind {
1960 GenericParamKind::Lifetime { .. } => !tcx.is_late_bound(param.hir_id),
1965 /// Returns a list of type predicates for the definition with ID `def_id`, including inferred
1966 /// lifetime constraints. This includes all predicates returned by `explicit_predicates_of`, plus
1967 /// inferred constraints concerning which regions outlive other regions.
1968 fn predicates_defined_on(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicates<'_> {
1969 debug!("predicates_defined_on({:?})", def_id);
1970 let mut result = tcx.explicit_predicates_of(def_id);
1971 debug!("predicates_defined_on: explicit_predicates_of({:?}) = {:?}", def_id, result,);
1972 let inferred_outlives = tcx.inferred_outlives_of(def_id);
1973 if !inferred_outlives.is_empty() {
1975 "predicates_defined_on: inferred_outlives_of({:?}) = {:?}",
1976 def_id, inferred_outlives,
1978 if result.predicates.is_empty() {
1979 result.predicates = inferred_outlives;
1981 result.predicates = tcx
1983 .alloc_from_iter(result.predicates.iter().chain(inferred_outlives).copied());
1987 debug!("predicates_defined_on({:?}) = {:?}", def_id, result);
1991 /// Returns a list of all type predicates (explicit and implicit) for the definition with
1992 /// ID `def_id`. This includes all predicates returned by `predicates_defined_on`, plus
1993 /// `Self: Trait` predicates for traits.
1994 fn predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicates<'_> {
1995 let mut result = tcx.predicates_defined_on(def_id);
1997 if tcx.is_trait(def_id) {
1998 // For traits, add `Self: Trait` predicate. This is
1999 // not part of the predicates that a user writes, but it
2000 // is something that one must prove in order to invoke a
2001 // method or project an associated type.
2003 // In the chalk setup, this predicate is not part of the
2004 // "predicates" for a trait item. But it is useful in
2005 // rustc because if you directly (e.g.) invoke a trait
2006 // method like `Trait::method(...)`, you must naturally
2007 // prove that the trait applies to the types that were
2008 // used, and adding the predicate into this list ensures
2009 // that this is done.
2011 // We use a DUMMY_SP here as a way to signal trait bounds that come
2012 // from the trait itself that *shouldn't* be shown as the source of
2013 // an obligation and instead be skipped. Otherwise we'd use
2014 // `tcx.def_span(def_id);`
2015 let span = rustc_span::DUMMY_SP;
2017 tcx.arena.alloc_from_iter(result.predicates.iter().copied().chain(std::iter::once((
2018 ty::TraitRef::identity(tcx, def_id).without_const().to_predicate(tcx),
2022 debug!("predicates_of(def_id={:?}) = {:?}", def_id, result);
2026 /// Returns a list of user-specified type predicates for the definition with ID `def_id`.
2027 /// N.B., this does not include any implied/inferred constraints.
2028 fn gather_explicit_predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicates<'_> {
2031 debug!("explicit_predicates_of(def_id={:?})", def_id);
2033 let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
2034 let node = tcx.hir().get(hir_id);
2036 let mut is_trait = None;
2037 let mut is_default_impl_trait = None;
2039 let icx = ItemCtxt::new(tcx, def_id);
2041 const NO_GENERICS: &hir::Generics<'_> = &hir::Generics::empty();
2043 // We use an `IndexSet` to preserves order of insertion.
2044 // Preserving the order of insertion is important here so as not to break UI tests.
2045 let mut predicates: FxIndexSet<(ty::Predicate<'_>, Span)> = FxIndexSet::default();
2047 let ast_generics = match node {
2048 Node::TraitItem(item) => &item.generics,
2050 Node::ImplItem(item) => &item.generics,
2052 Node::Item(item) => {
2054 ItemKind::Impl(ref impl_) => {
2055 if impl_.defaultness.is_default() {
2056 is_default_impl_trait = tcx.impl_trait_ref(def_id).map(ty::Binder::dummy);
2060 ItemKind::Fn(.., ref generics, _)
2061 | ItemKind::TyAlias(_, ref generics)
2062 | ItemKind::Enum(_, ref generics)
2063 | ItemKind::Struct(_, ref generics)
2064 | ItemKind::Union(_, ref generics) => generics,
2066 ItemKind::Trait(_, _, ref generics, ..) => {
2067 is_trait = Some(ty::TraitRef::identity(tcx, def_id));
2070 ItemKind::TraitAlias(ref generics, _) => {
2071 is_trait = Some(ty::TraitRef::identity(tcx, def_id));
2074 ItemKind::OpaqueTy(OpaqueTy {
2075 origin: hir::OpaqueTyOrigin::AsyncFn(..) | hir::OpaqueTyOrigin::FnReturn(..),
2078 // return-position impl trait
2080 // We don't inherit predicates from the parent here:
2081 // If we have, say `fn f<'a, T: 'a>() -> impl Sized {}`
2082 // then the return type is `f::<'static, T>::{{opaque}}`.
2084 // If we inherited the predicates of `f` then we would
2085 // require that `T: 'static` to show that the return
2086 // type is well-formed.
2088 // The only way to have something with this opaque type
2089 // is from the return type of the containing function,
2090 // which will ensure that the function's predicates
2092 return ty::GenericPredicates { parent: None, predicates: &[] };
2094 ItemKind::OpaqueTy(OpaqueTy {
2096 origin: hir::OpaqueTyOrigin::TyAlias,
2099 // type-alias impl trait
2107 Node::ForeignItem(item) => match item.kind {
2108 ForeignItemKind::Static(..) => NO_GENERICS,
2109 ForeignItemKind::Fn(_, _, ref generics) => generics,
2110 ForeignItemKind::Type => NO_GENERICS,
2116 let generics = tcx.generics_of(def_id);
2117 let parent_count = generics.parent_count as u32;
2118 let has_own_self = generics.has_self && parent_count == 0;
2120 // Below we'll consider the bounds on the type parameters (including `Self`)
2121 // and the explicit where-clauses, but to get the full set of predicates
2122 // on a trait we need to add in the supertrait bounds and bounds found on
2123 // associated types.
2124 if let Some(_trait_ref) = is_trait {
2125 predicates.extend(tcx.super_predicates_of(def_id).predicates.iter().cloned());
2128 // In default impls, we can assume that the self type implements
2129 // the trait. So in:
2131 // default impl Foo for Bar { .. }
2133 // we add a default where clause `Foo: Bar`. We do a similar thing for traits
2134 // (see below). Recall that a default impl is not itself an impl, but rather a
2135 // set of defaults that can be incorporated into another impl.
2136 if let Some(trait_ref) = is_default_impl_trait {
2137 predicates.insert((trait_ref.without_const().to_predicate(tcx), tcx.def_span(def_id)));
2140 // Collect the region predicates that were declared inline as
2141 // well. In the case of parameters declared on a fn or method, we
2142 // have to be careful to only iterate over early-bound regions.
2143 let mut index = parent_count + has_own_self as u32;
2144 for param in early_bound_lifetimes_from_generics(tcx, ast_generics) {
2145 let region = tcx.mk_region(ty::ReEarlyBound(ty::EarlyBoundRegion {
2146 def_id: tcx.hir().local_def_id(param.hir_id).to_def_id(),
2148 name: param.name.ident().name,
2153 GenericParamKind::Lifetime { .. } => {
2154 param.bounds.iter().for_each(|bound| match bound {
2155 hir::GenericBound::Outlives(lt) => {
2156 let bound = <dyn AstConv<'_>>::ast_region_to_region(&icx, lt, None);
2157 let outlives = ty::Binder::dummy(ty::OutlivesPredicate(region, bound));
2158 predicates.insert((outlives.to_predicate(tcx), lt.span));
2167 // Collect the predicates that were written inline by the user on each
2168 // type parameter (e.g., `<T: Foo>`).
2169 for param in ast_generics.params {
2171 // We already dealt with early bound lifetimes above.
2172 GenericParamKind::Lifetime { .. } => (),
2173 GenericParamKind::Type { .. } => {
2174 let name = param.name.ident().name;
2175 let param_ty = ty::ParamTy::new(index, name).to_ty(tcx);
2178 let mut bounds = <dyn AstConv<'_>>::compute_bounds(&icx, param_ty, param.bounds);
2179 // Params are implicitly sized unless a `?Sized` bound is found
2180 <dyn AstConv<'_>>::add_implicitly_sized(
2184 Some((param.hir_id, ast_generics.where_clause.predicates)),
2187 predicates.extend(bounds.predicates(tcx, param_ty));
2189 GenericParamKind::Const { .. } => {
2190 // Bounds on const parameters are currently not possible.
2191 debug_assert!(param.bounds.is_empty());
2197 // Add in the bounds that appear in the where-clause.
2198 let where_clause = &ast_generics.where_clause;
2199 for predicate in where_clause.predicates {
2201 hir::WherePredicate::BoundPredicate(bound_pred) => {
2202 let ty = icx.to_ty(bound_pred.bounded_ty);
2203 let bound_vars = icx.tcx.late_bound_vars(bound_pred.bounded_ty.hir_id);
2205 // Keep the type around in a dummy predicate, in case of no bounds.
2206 // That way, `where Ty:` is not a complete noop (see #53696) and `Ty`
2207 // is still checked for WF.
2208 if bound_pred.bounds.is_empty() {
2209 if let ty::Param(_) = ty.kind() {
2210 // This is a `where T:`, which can be in the HIR from the
2211 // transformation that moves `?Sized` to `T`'s declaration.
2212 // We can skip the predicate because type parameters are
2213 // trivially WF, but also we *should*, to avoid exposing
2214 // users who never wrote `where Type:,` themselves, to
2215 // compiler/tooling bugs from not handling WF predicates.
2217 let span = bound_pred.bounded_ty.span;
2218 let re_root_empty = tcx.lifetimes.re_root_empty;
2219 let predicate = ty::Binder::bind_with_vars(
2220 ty::PredicateKind::TypeOutlives(ty::OutlivesPredicate(
2226 predicates.insert((predicate.to_predicate(tcx), span));
2230 let mut bounds = Bounds::default();
2231 <dyn AstConv<'_>>::add_bounds(
2234 bound_pred.bounds.iter(),
2238 predicates.extend(bounds.predicates(tcx, ty));
2241 hir::WherePredicate::RegionPredicate(region_pred) => {
2242 let r1 = <dyn AstConv<'_>>::ast_region_to_region(&icx, ®ion_pred.lifetime, None);
2243 predicates.extend(region_pred.bounds.iter().map(|bound| {
2244 let (r2, span) = match bound {
2245 hir::GenericBound::Outlives(lt) => {
2246 (<dyn AstConv<'_>>::ast_region_to_region(&icx, lt, None), lt.span)
2250 let pred = ty::Binder::dummy(ty::PredicateKind::RegionOutlives(
2251 ty::OutlivesPredicate(r1, r2),
2253 .to_predicate(icx.tcx);
2259 hir::WherePredicate::EqPredicate(..) => {
2265 if tcx.features().generic_const_exprs {
2266 predicates.extend(const_evaluatable_predicates_of(tcx, def_id.expect_local()));
2269 let mut predicates: Vec<_> = predicates.into_iter().collect();
2271 // Subtle: before we store the predicates into the tcx, we
2272 // sort them so that predicates like `T: Foo<Item=U>` come
2273 // before uses of `U`. This avoids false ambiguity errors
2274 // in trait checking. See `setup_constraining_predicates`
2276 if let Node::Item(&Item { kind: ItemKind::Impl { .. }, .. }) = node {
2277 let self_ty = tcx.type_of(def_id);
2278 let trait_ref = tcx.impl_trait_ref(def_id);
2279 cgp::setup_constraining_predicates(
2283 &mut cgp::parameters_for_impl(tcx, self_ty, trait_ref),
2287 let result = ty::GenericPredicates {
2288 parent: generics.parent,
2289 predicates: tcx.arena.alloc_from_iter(predicates),
2291 debug!("explicit_predicates_of(def_id={:?}) = {:?}", def_id, result);
2295 fn const_evaluatable_predicates_of<'tcx>(
2298 ) -> FxIndexSet<(ty::Predicate<'tcx>, Span)> {
2299 struct ConstCollector<'tcx> {
2301 preds: FxIndexSet<(ty::Predicate<'tcx>, Span)>,
2304 impl<'tcx> intravisit::Visitor<'tcx> for ConstCollector<'tcx> {
2305 type Map = Map<'tcx>;
2307 fn nested_visit_map(&mut self) -> intravisit::NestedVisitorMap<Self::Map> {
2308 intravisit::NestedVisitorMap::None
2311 fn visit_anon_const(&mut self, c: &'tcx hir::AnonConst) {
2312 let def_id = self.tcx.hir().local_def_id(c.hir_id);
2313 let ct = ty::Const::from_anon_const(self.tcx, def_id);
2314 if let ty::ConstKind::Unevaluated(uv) = ct.val {
2315 assert_eq!(uv.promoted, None);
2316 let span = self.tcx.hir().span(c.hir_id);
2318 ty::Binder::dummy(ty::PredicateKind::ConstEvaluatable(uv.shrink()))
2319 .to_predicate(self.tcx),
2325 fn visit_const_param_default(&mut self, _param: HirId, _ct: &'tcx hir::AnonConst) {
2326 // Do not look into const param defaults,
2327 // these get checked when they are actually instantiated.
2329 // We do not want the following to error:
2331 // struct Foo<const N: usize, const M: usize = { N + 1 }>;
2332 // struct Bar<const N: usize>(Foo<N, 3>);
2336 let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
2337 let node = tcx.hir().get(hir_id);
2339 let mut collector = ConstCollector { tcx, preds: FxIndexSet::default() };
2340 if let hir::Node::Item(item) = node {
2341 if let hir::ItemKind::Impl(ref impl_) = item.kind {
2342 if let Some(of_trait) = &impl_.of_trait {
2343 debug!("const_evaluatable_predicates_of({:?}): visit impl trait_ref", def_id);
2344 collector.visit_trait_ref(of_trait);
2347 debug!("const_evaluatable_predicates_of({:?}): visit_self_ty", def_id);
2348 collector.visit_ty(impl_.self_ty);
2352 if let Some(generics) = node.generics() {
2353 debug!("const_evaluatable_predicates_of({:?}): visit_generics", def_id);
2354 collector.visit_generics(generics);
2357 if let Some(fn_sig) = tcx.hir().fn_sig_by_hir_id(hir_id) {
2358 debug!("const_evaluatable_predicates_of({:?}): visit_fn_decl", def_id);
2359 collector.visit_fn_decl(fn_sig.decl);
2361 debug!("const_evaluatable_predicates_of({:?}) = {:?}", def_id, collector.preds);
2366 fn trait_explicit_predicates_and_bounds(
2369 ) -> ty::GenericPredicates<'_> {
2370 assert_eq!(tcx.def_kind(def_id), DefKind::Trait);
2371 gather_explicit_predicates_of(tcx, def_id.to_def_id())
2374 fn explicit_predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicates<'_> {
2375 let def_kind = tcx.def_kind(def_id);
2376 if let DefKind::Trait = def_kind {
2377 // Remove bounds on associated types from the predicates, they will be
2378 // returned by `explicit_item_bounds`.
2379 let predicates_and_bounds = tcx.trait_explicit_predicates_and_bounds(def_id.expect_local());
2380 let trait_identity_substs = InternalSubsts::identity_for_item(tcx, def_id);
2382 let is_assoc_item_ty = |ty: Ty<'_>| {
2383 // For a predicate from a where clause to become a bound on an
2385 // * It must use the identity substs of the item.
2386 // * Since any generic parameters on the item are not in scope,
2387 // this means that the item is not a GAT, and its identity
2388 // substs are the same as the trait's.
2389 // * It must be an associated type for this trait (*not* a
2391 if let ty::Projection(projection) = ty.kind() {
2392 projection.substs == trait_identity_substs
2393 && tcx.associated_item(projection.item_def_id).container.id() == def_id
2399 let predicates: Vec<_> = predicates_and_bounds
2403 .filter(|(pred, _)| match pred.kind().skip_binder() {
2404 ty::PredicateKind::Trait(tr) => !is_assoc_item_ty(tr.self_ty()),
2405 ty::PredicateKind::Projection(proj) => {
2406 !is_assoc_item_ty(proj.projection_ty.self_ty())
2408 ty::PredicateKind::TypeOutlives(outlives) => !is_assoc_item_ty(outlives.0),
2412 if predicates.len() == predicates_and_bounds.predicates.len() {
2413 predicates_and_bounds
2415 ty::GenericPredicates {
2416 parent: predicates_and_bounds.parent,
2417 predicates: tcx.arena.alloc_slice(&predicates),
2421 if matches!(def_kind, DefKind::AnonConst) && tcx.lazy_normalization() {
2422 let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
2423 if tcx.hir().opt_const_param_default_param_hir_id(hir_id).is_some() {
2424 // In `generics_of` we set the generics' parent to be our parent's parent which means that
2425 // we lose out on the predicates of our actual parent if we dont return those predicates here.
2426 // (See comment in `generics_of` for more information on why the parent shenanigans is necessary)
2428 // struct Foo<T, const N: usize = { <T as Trait>::ASSOC }>(T) where T: Trait;
2429 // ^^^ ^^^^^^^^^^^^^^^^^^^^^^^ the def id we are calling
2430 // ^^^ explicit_predicates_of on
2431 // parent item we dont have set as the
2432 // parent of generics returned by `generics_of`
2434 // In the above code we want the anon const to have predicates in its param env for `T: Trait`
2435 let item_id = tcx.hir().get_parent_item(hir_id);
2436 let item_def_id = tcx.hir().local_def_id(item_id).to_def_id();
2437 // In the above code example we would be calling `explicit_predicates_of(Foo)` here
2438 return tcx.explicit_predicates_of(item_def_id);
2441 gather_explicit_predicates_of(tcx, def_id)
2445 /// Converts a specific `GenericBound` from the AST into a set of
2446 /// predicates that apply to the self type. A vector is returned
2447 /// because this can be anywhere from zero predicates (`T: ?Sized` adds no
2448 /// predicates) to one (`T: Foo`) to many (`T: Bar<X = i32>` adds `T: Bar`
2449 /// and `<T as Bar>::X == i32`).
2450 fn predicates_from_bound<'tcx>(
2451 astconv: &dyn AstConv<'tcx>,
2453 bound: &'tcx hir::GenericBound<'tcx>,
2454 bound_vars: &'tcx ty::List<ty::BoundVariableKind>,
2455 ) -> Vec<(ty::Predicate<'tcx>, Span)> {
2456 let mut bounds = Bounds::default();
2457 astconv.add_bounds(param_ty, [bound].into_iter(), &mut bounds, bound_vars);
2458 bounds.predicates(astconv.tcx(), param_ty)
2461 fn compute_sig_of_foreign_fn_decl<'tcx>(
2464 decl: &'tcx hir::FnDecl<'tcx>,
2467 ) -> ty::PolyFnSig<'tcx> {
2468 let unsafety = if abi == abi::Abi::RustIntrinsic {
2469 intrinsic_operation_unsafety(tcx.item_name(def_id))
2471 hir::Unsafety::Unsafe
2473 let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
2474 let fty = <dyn AstConv<'_>>::ty_of_fn(
2475 &ItemCtxt::new(tcx, def_id),
2480 &hir::Generics::empty(),
2485 // Feature gate SIMD types in FFI, since I am not sure that the
2486 // ABIs are handled at all correctly. -huonw
2487 if abi != abi::Abi::RustIntrinsic
2488 && abi != abi::Abi::PlatformIntrinsic
2489 && !tcx.features().simd_ffi
2491 let check = |ast_ty: &hir::Ty<'_>, ty: Ty<'_>| {
2496 .span_to_snippet(ast_ty.span)
2497 .map_or_else(|_| String::new(), |s| format!(" `{}`", s));
2502 "use of SIMD type{} in FFI is highly experimental and \
2503 may result in invalid code",
2507 .help("add `#![feature(simd_ffi)]` to the crate attributes to enable")
2511 for (input, ty) in iter::zip(decl.inputs, fty.inputs().skip_binder()) {
2514 if let hir::FnRetTy::Return(ref ty) = decl.output {
2515 check(ty, fty.output().skip_binder())
2522 fn is_foreign_item(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
2523 match tcx.hir().get_if_local(def_id) {
2524 Some(Node::ForeignItem(..)) => true,
2526 _ => bug!("is_foreign_item applied to non-local def-id {:?}", def_id),
2530 fn static_mutability(tcx: TyCtxt<'_>, def_id: DefId) -> Option<hir::Mutability> {
2531 match tcx.hir().get_if_local(def_id) {
2533 Node::Item(&hir::Item { kind: hir::ItemKind::Static(_, mutbl, _), .. })
2534 | Node::ForeignItem(&hir::ForeignItem {
2535 kind: hir::ForeignItemKind::Static(_, mutbl),
2540 _ => bug!("static_mutability applied to non-local def-id {:?}", def_id),
2544 fn generator_kind(tcx: TyCtxt<'_>, def_id: DefId) -> Option<hir::GeneratorKind> {
2545 match tcx.hir().get_if_local(def_id) {
2546 Some(Node::Expr(&rustc_hir::Expr {
2547 kind: rustc_hir::ExprKind::Closure(_, _, body_id, _, _),
2549 })) => tcx.hir().body(body_id).generator_kind(),
2551 _ => bug!("generator_kind applied to non-local def-id {:?}", def_id),
2555 fn from_target_feature(
2558 attr: &ast::Attribute,
2559 supported_target_features: &FxHashMap<String, Option<Symbol>>,
2560 target_features: &mut Vec<Symbol>,
2562 let list = match attr.meta_item_list() {
2566 let bad_item = |span| {
2567 let msg = "malformed `target_feature` attribute input";
2568 let code = "enable = \"..\"".to_owned();
2570 .struct_span_err(span, msg)
2571 .span_suggestion(span, "must be of the form", code, Applicability::HasPlaceholders)
2574 let rust_features = tcx.features();
2576 // Only `enable = ...` is accepted in the meta-item list.
2577 if !item.has_name(sym::enable) {
2578 bad_item(item.span());
2582 // Must be of the form `enable = "..."` (a string).
2583 let value = match item.value_str() {
2584 Some(value) => value,
2586 bad_item(item.span());
2591 // We allow comma separation to enable multiple features.
2592 target_features.extend(value.as_str().split(',').filter_map(|feature| {
2593 let feature_gate = match supported_target_features.get(feature) {
2597 format!("the feature named `{}` is not valid for this target", feature);
2598 let mut err = tcx.sess.struct_span_err(item.span(), &msg);
2601 format!("`{}` is not valid for this target", feature),
2603 if let Some(stripped) = feature.strip_prefix('+') {
2604 let valid = supported_target_features.contains_key(stripped);
2606 err.help("consider removing the leading `+` in the feature name");
2614 // Only allow features whose feature gates have been enabled.
2615 let allowed = match feature_gate.as_ref().copied() {
2616 Some(sym::arm_target_feature) => rust_features.arm_target_feature,
2617 Some(sym::aarch64_target_feature) => rust_features.aarch64_target_feature,
2618 Some(sym::hexagon_target_feature) => rust_features.hexagon_target_feature,
2619 Some(sym::powerpc_target_feature) => rust_features.powerpc_target_feature,
2620 Some(sym::mips_target_feature) => rust_features.mips_target_feature,
2621 Some(sym::riscv_target_feature) => rust_features.riscv_target_feature,
2622 Some(sym::avx512_target_feature) => rust_features.avx512_target_feature,
2623 Some(sym::sse4a_target_feature) => rust_features.sse4a_target_feature,
2624 Some(sym::tbm_target_feature) => rust_features.tbm_target_feature,
2625 Some(sym::wasm_target_feature) => rust_features.wasm_target_feature,
2626 Some(sym::cmpxchg16b_target_feature) => rust_features.cmpxchg16b_target_feature,
2627 Some(sym::adx_target_feature) => rust_features.adx_target_feature,
2628 Some(sym::movbe_target_feature) => rust_features.movbe_target_feature,
2629 Some(sym::rtm_target_feature) => rust_features.rtm_target_feature,
2630 Some(sym::f16c_target_feature) => rust_features.f16c_target_feature,
2631 Some(sym::ermsb_target_feature) => rust_features.ermsb_target_feature,
2632 Some(sym::bpf_target_feature) => rust_features.bpf_target_feature,
2633 Some(name) => bug!("unknown target feature gate {}", name),
2636 if !allowed && id.is_local() {
2638 &tcx.sess.parse_sess,
2639 feature_gate.unwrap(),
2641 &format!("the target feature `{}` is currently unstable", feature),
2645 Some(Symbol::intern(feature))
2650 fn linkage_by_name(tcx: TyCtxt<'_>, def_id: DefId, name: &str) -> Linkage {
2651 use rustc_middle::mir::mono::Linkage::*;
2653 // Use the names from src/llvm/docs/LangRef.rst here. Most types are only
2654 // applicable to variable declarations and may not really make sense for
2655 // Rust code in the first place but allow them anyway and trust that the
2656 // user knows what s/he's doing. Who knows, unanticipated use cases may pop
2657 // up in the future.
2659 // ghost, dllimport, dllexport and linkonce_odr_autohide are not supported
2660 // and don't have to be, LLVM treats them as no-ops.
2662 "appending" => Appending,
2663 "available_externally" => AvailableExternally,
2665 "extern_weak" => ExternalWeak,
2666 "external" => External,
2667 "internal" => Internal,
2668 "linkonce" => LinkOnceAny,
2669 "linkonce_odr" => LinkOnceODR,
2670 "private" => Private,
2672 "weak_odr" => WeakODR,
2674 let span = tcx.hir().span_if_local(def_id);
2675 if let Some(span) = span {
2676 tcx.sess.span_fatal(span, "invalid linkage specified")
2678 tcx.sess.fatal(&format!("invalid linkage specified: {}", name))
2684 fn codegen_fn_attrs(tcx: TyCtxt<'_>, id: DefId) -> CodegenFnAttrs {
2685 let attrs = tcx.get_attrs(id);
2687 let mut codegen_fn_attrs = CodegenFnAttrs::new();
2688 if tcx.should_inherit_track_caller(id) {
2689 codegen_fn_attrs.flags |= CodegenFnAttrFlags::TRACK_CALLER;
2692 // With -Z panic-in-drop=abort, drop_in_place never unwinds.
2693 if tcx.sess.opts.debugging_opts.panic_in_drop == PanicStrategy::Abort {
2694 if Some(id) == tcx.lang_items().drop_in_place_fn() {
2695 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NEVER_UNWIND;
2699 let supported_target_features = tcx.supported_target_features(LOCAL_CRATE);
2701 let mut inline_span = None;
2702 let mut link_ordinal_span = None;
2703 let mut no_sanitize_span = None;
2704 for attr in attrs.iter() {
2705 if attr.has_name(sym::cold) {
2706 codegen_fn_attrs.flags |= CodegenFnAttrFlags::COLD;
2707 } else if attr.has_name(sym::rustc_allocator) {
2708 codegen_fn_attrs.flags |= CodegenFnAttrFlags::ALLOCATOR;
2709 } else if attr.has_name(sym::ffi_returns_twice) {
2710 if tcx.is_foreign_item(id) {
2711 codegen_fn_attrs.flags |= CodegenFnAttrFlags::FFI_RETURNS_TWICE;
2713 // `#[ffi_returns_twice]` is only allowed `extern fn`s.
2718 "`#[ffi_returns_twice]` may only be used on foreign functions"
2722 } else if attr.has_name(sym::ffi_pure) {
2723 if tcx.is_foreign_item(id) {
2724 if attrs.iter().any(|a| a.has_name(sym::ffi_const)) {
2725 // `#[ffi_const]` functions cannot be `#[ffi_pure]`
2730 "`#[ffi_const]` function cannot be `#[ffi_pure]`"
2734 codegen_fn_attrs.flags |= CodegenFnAttrFlags::FFI_PURE;
2737 // `#[ffi_pure]` is only allowed on foreign functions
2742 "`#[ffi_pure]` may only be used on foreign functions"
2746 } else if attr.has_name(sym::ffi_const) {
2747 if tcx.is_foreign_item(id) {
2748 codegen_fn_attrs.flags |= CodegenFnAttrFlags::FFI_CONST;
2750 // `#[ffi_const]` is only allowed on foreign functions
2755 "`#[ffi_const]` may only be used on foreign functions"
2759 } else if attr.has_name(sym::rustc_allocator_nounwind) {
2760 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NEVER_UNWIND;
2761 } else if attr.has_name(sym::naked) {
2762 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NAKED;
2763 } else if attr.has_name(sym::no_mangle) {
2764 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_MANGLE;
2765 } else if attr.has_name(sym::no_coverage) {
2766 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_COVERAGE;
2767 } else if attr.has_name(sym::rustc_std_internal_symbol) {
2768 codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL;
2769 } else if attr.has_name(sym::used) {
2770 codegen_fn_attrs.flags |= CodegenFnAttrFlags::USED;
2771 } else if attr.has_name(sym::cmse_nonsecure_entry) {
2772 if !matches!(tcx.fn_sig(id).abi(), abi::Abi::C { .. }) {
2777 "`#[cmse_nonsecure_entry]` requires C ABI"
2781 if !tcx.sess.target.llvm_target.contains("thumbv8m") {
2782 struct_span_err!(tcx.sess, attr.span, E0775, "`#[cmse_nonsecure_entry]` is only valid for targets with the TrustZone-M extension")
2785 codegen_fn_attrs.flags |= CodegenFnAttrFlags::CMSE_NONSECURE_ENTRY;
2786 } else if attr.has_name(sym::thread_local) {
2787 codegen_fn_attrs.flags |= CodegenFnAttrFlags::THREAD_LOCAL;
2788 } else if attr.has_name(sym::track_caller) {
2789 if !tcx.is_closure(id) && tcx.fn_sig(id).abi() != abi::Abi::Rust {
2790 struct_span_err!(tcx.sess, attr.span, E0737, "`#[track_caller]` requires Rust ABI")
2793 if tcx.is_closure(id) && !tcx.features().closure_track_caller {
2795 &tcx.sess.parse_sess,
2796 sym::closure_track_caller,
2798 "`#[track_caller]` on closures is currently unstable",
2802 codegen_fn_attrs.flags |= CodegenFnAttrFlags::TRACK_CALLER;
2803 } else if attr.has_name(sym::export_name) {
2804 if let Some(s) = attr.value_str() {
2805 if s.as_str().contains('\0') {
2806 // `#[export_name = ...]` will be converted to a null-terminated string,
2807 // so it may not contain any null characters.
2812 "`export_name` may not contain null characters"
2816 codegen_fn_attrs.export_name = Some(s);
2818 } else if attr.has_name(sym::target_feature) {
2819 if !tcx.is_closure(id) && tcx.fn_sig(id).unsafety() == hir::Unsafety::Normal {
2820 if tcx.sess.target.is_like_wasm || tcx.sess.opts.actually_rustdoc {
2821 // The `#[target_feature]` attribute is allowed on
2822 // WebAssembly targets on all functions, including safe
2823 // ones. Other targets require that `#[target_feature]` is
2824 // only applied to unsafe funtions (pending the
2825 // `target_feature_11` feature) because on most targets
2826 // execution of instructions that are not supported is
2827 // considered undefined behavior. For WebAssembly which is a
2828 // 100% safe target at execution time it's not possible to
2829 // execute undefined instructions, and even if a future
2830 // feature was added in some form for this it would be a
2831 // deterministic trap. There is no undefined behavior when
2832 // executing WebAssembly so `#[target_feature]` is allowed
2833 // on safe functions (but again, only for WebAssembly)
2835 // Note that this is also allowed if `actually_rustdoc` so
2836 // if a target is documenting some wasm-specific code then
2837 // it's not spuriously denied.
2838 } else if !tcx.features().target_feature_11 {
2839 let mut err = feature_err(
2840 &tcx.sess.parse_sess,
2841 sym::target_feature_11,
2843 "`#[target_feature(..)]` can only be applied to `unsafe` functions",
2845 err.span_label(tcx.def_span(id), "not an `unsafe` function");
2847 } else if let Some(local_id) = id.as_local() {
2848 check_target_feature_trait_unsafe(tcx, local_id, attr.span);
2851 from_target_feature(
2855 supported_target_features,
2856 &mut codegen_fn_attrs.target_features,
2858 } else if attr.has_name(sym::linkage) {
2859 if let Some(val) = attr.value_str() {
2860 codegen_fn_attrs.linkage = Some(linkage_by_name(tcx, id, val.as_str()));
2862 } else if attr.has_name(sym::link_section) {
2863 if let Some(val) = attr.value_str() {
2864 if val.as_str().bytes().any(|b| b == 0) {
2866 "illegal null byte in link_section \
2870 tcx.sess.span_err(attr.span, &msg);
2872 codegen_fn_attrs.link_section = Some(val);
2875 } else if attr.has_name(sym::link_name) {
2876 codegen_fn_attrs.link_name = attr.value_str();
2877 } else if attr.has_name(sym::link_ordinal) {
2878 link_ordinal_span = Some(attr.span);
2879 if let ordinal @ Some(_) = check_link_ordinal(tcx, attr) {
2880 codegen_fn_attrs.link_ordinal = ordinal;
2882 } else if attr.has_name(sym::no_sanitize) {
2883 no_sanitize_span = Some(attr.span);
2884 if let Some(list) = attr.meta_item_list() {
2885 for item in list.iter() {
2886 if item.has_name(sym::address) {
2887 codegen_fn_attrs.no_sanitize |= SanitizerSet::ADDRESS;
2888 } else if item.has_name(sym::cfi) {
2889 codegen_fn_attrs.no_sanitize |= SanitizerSet::CFI;
2890 } else if item.has_name(sym::memory) {
2891 codegen_fn_attrs.no_sanitize |= SanitizerSet::MEMORY;
2892 } else if item.has_name(sym::thread) {
2893 codegen_fn_attrs.no_sanitize |= SanitizerSet::THREAD;
2894 } else if item.has_name(sym::hwaddress) {
2895 codegen_fn_attrs.no_sanitize |= SanitizerSet::HWADDRESS;
2898 .struct_span_err(item.span(), "invalid argument for `no_sanitize`")
2899 .note("expected one of: `address`, `hwaddress`, `memory` or `thread`")
2904 } else if attr.has_name(sym::instruction_set) {
2905 codegen_fn_attrs.instruction_set = match attr.meta_kind() {
2906 Some(MetaItemKind::List(ref items)) => match items.as_slice() {
2907 [NestedMetaItem::MetaItem(set)] => {
2909 set.path.segments.iter().map(|x| x.ident.name).collect::<Vec<_>>();
2910 match segments.as_slice() {
2911 [sym::arm, sym::a32] | [sym::arm, sym::t32] => {
2912 if !tcx.sess.target.has_thumb_interworking {
2914 tcx.sess.diagnostic(),
2917 "target does not support `#[instruction_set]`"
2921 } else if segments[1] == sym::a32 {
2922 Some(InstructionSetAttr::ArmA32)
2923 } else if segments[1] == sym::t32 {
2924 Some(InstructionSetAttr::ArmT32)
2931 tcx.sess.diagnostic(),
2934 "invalid instruction set specified",
2943 tcx.sess.diagnostic(),
2946 "`#[instruction_set]` requires an argument"
2953 tcx.sess.diagnostic(),
2956 "cannot specify more than one instruction set"
2964 tcx.sess.diagnostic(),
2967 "must specify an instruction set"
2973 } else if attr.has_name(sym::repr) {
2974 codegen_fn_attrs.alignment = match attr.meta_item_list() {
2975 Some(items) => match items.as_slice() {
2976 [item] => match item.name_value_literal() {
2977 Some((sym::align, literal)) => {
2978 let alignment = rustc_attr::parse_alignment(&literal.kind);
2981 Ok(align) => Some(align),
2984 tcx.sess.diagnostic(),
2987 "invalid `repr(align)` attribute: {}",
3006 codegen_fn_attrs.inline = attrs.iter().fold(InlineAttr::None, |ia, attr| {
3007 if !attr.has_name(sym::inline) {
3010 match attr.meta_kind() {
3011 Some(MetaItemKind::Word) => InlineAttr::Hint,
3012 Some(MetaItemKind::List(ref items)) => {
3013 inline_span = Some(attr.span);
3014 if items.len() != 1 {
3016 tcx.sess.diagnostic(),
3019 "expected one argument"
3023 } else if list_contains_name(&items, sym::always) {
3025 } else if list_contains_name(&items, sym::never) {
3029 tcx.sess.diagnostic(),
3039 Some(MetaItemKind::NameValue(_)) => ia,
3044 codegen_fn_attrs.optimize = attrs.iter().fold(OptimizeAttr::None, |ia, attr| {
3045 if !attr.has_name(sym::optimize) {
3048 let err = |sp, s| struct_span_err!(tcx.sess.diagnostic(), sp, E0722, "{}", s).emit();
3049 match attr.meta_kind() {
3050 Some(MetaItemKind::Word) => {
3051 err(attr.span, "expected one argument");
3054 Some(MetaItemKind::List(ref items)) => {
3055 inline_span = Some(attr.span);
3056 if items.len() != 1 {
3057 err(attr.span, "expected one argument");
3059 } else if list_contains_name(&items, sym::size) {
3061 } else if list_contains_name(&items, sym::speed) {
3064 err(items[0].span(), "invalid argument");
3068 Some(MetaItemKind::NameValue(_)) => ia,
3073 // #73631: closures inherit `#[target_feature]` annotations
3074 if tcx.features().target_feature_11 && tcx.is_closure(id) {
3075 let owner_id = tcx.parent(id).expect("closure should have a parent");
3078 .extend(tcx.codegen_fn_attrs(owner_id).target_features.iter().copied())
3081 // If a function uses #[target_feature] it can't be inlined into general
3082 // purpose functions as they wouldn't have the right target features
3083 // enabled. For that reason we also forbid #[inline(always)] as it can't be
3085 if !codegen_fn_attrs.target_features.is_empty() {
3086 if codegen_fn_attrs.inline == InlineAttr::Always {
3087 if let Some(span) = inline_span {
3090 "cannot use `#[inline(always)]` with \
3091 `#[target_feature]`",
3097 if !codegen_fn_attrs.no_sanitize.is_empty() {
3098 if codegen_fn_attrs.inline == InlineAttr::Always {
3099 if let (Some(no_sanitize_span), Some(inline_span)) = (no_sanitize_span, inline_span) {
3100 let hir_id = tcx.hir().local_def_id_to_hir_id(id.expect_local());
3101 tcx.struct_span_lint_hir(
3102 lint::builtin::INLINE_NO_SANITIZE,
3106 lint.build("`no_sanitize` will have no effect after inlining")
3107 .span_note(inline_span, "inlining requested here")
3115 // Weak lang items have the same semantics as "std internal" symbols in the
3116 // sense that they're preserved through all our LTO passes and only
3117 // strippable by the linker.
3119 // Additionally weak lang items have predetermined symbol names.
3120 if tcx.is_weak_lang_item(id) {
3121 codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL;
3123 let check_name = |attr: &Attribute, sym| attr.has_name(sym);
3124 if let Some(name) = weak_lang_items::link_name(check_name, attrs) {
3125 codegen_fn_attrs.export_name = Some(name);
3126 codegen_fn_attrs.link_name = Some(name);
3128 check_link_name_xor_ordinal(tcx, &codegen_fn_attrs, link_ordinal_span);
3130 // Internal symbols to the standard library all have no_mangle semantics in
3131 // that they have defined symbol names present in the function name. This
3132 // also applies to weak symbols where they all have known symbol names.
3133 if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL) {
3134 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_MANGLE;
3137 // Any linkage to LLVM intrinsics for now forcibly marks them all as never
3138 // unwinds since LLVM sometimes can't handle codegen which `invoke`s
3139 // intrinsic functions.
3140 if let Some(name) = &codegen_fn_attrs.link_name {
3141 if name.as_str().starts_with("llvm.") {
3142 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NEVER_UNWIND;
3149 /// Checks if the provided DefId is a method in a trait impl for a trait which has track_caller
3150 /// applied to the method prototype.
3151 fn should_inherit_track_caller(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
3152 if let Some(impl_item) = tcx.opt_associated_item(def_id) {
3153 if let ty::AssocItemContainer::ImplContainer(_) = impl_item.container {
3154 if let Some(trait_item) = impl_item.trait_item_def_id {
3156 .codegen_fn_attrs(trait_item)
3158 .intersects(CodegenFnAttrFlags::TRACK_CALLER);
3166 fn check_link_ordinal(tcx: TyCtxt<'_>, attr: &ast::Attribute) -> Option<u16> {
3167 use rustc_ast::{Lit, LitIntType, LitKind};
3168 let meta_item_list = attr.meta_item_list();
3169 let meta_item_list: Option<&[ast::NestedMetaItem]> = meta_item_list.as_ref().map(Vec::as_ref);
3170 let sole_meta_list = match meta_item_list {
3171 Some([item]) => item.literal(),
3174 .struct_span_err(attr.span, "incorrect number of arguments to `#[link_ordinal]`")
3175 .note("the attribute requires exactly one argument")
3181 if let Some(Lit { kind: LitKind::Int(ordinal, LitIntType::Unsuffixed), .. }) = sole_meta_list {
3182 // According to the table at https://docs.microsoft.com/en-us/windows/win32/debug/pe-format#import-header,
3183 // the ordinal must fit into 16 bits. Similarly, the Ordinal field in COFFShortExport (defined
3184 // in llvm/include/llvm/Object/COFFImportFile.h), which we use to communicate import information
3185 // to LLVM for `#[link(kind = "raw-dylib"_])`, is also defined to be uint16_t.
3187 // FIXME: should we allow an ordinal of 0? The MSVC toolchain has inconsistent support for this:
3188 // both LINK.EXE and LIB.EXE signal errors and abort when given a .DEF file that specifies
3189 // a zero ordinal. However, llvm-dlltool is perfectly happy to generate an import library
3190 // for such a .DEF file, and MSVC's LINK.EXE is also perfectly happy to consume an import
3191 // library produced by LLVM with an ordinal of 0, and it generates an .EXE. (I don't know yet
3192 // if the resulting EXE runs, as I haven't yet built the necessary DLL -- see earlier comment
3193 // about LINK.EXE failing.)
3194 if *ordinal <= u16::MAX as u128 {
3195 Some(*ordinal as u16)
3197 let msg = format!("ordinal value in `link_ordinal` is too large: `{}`", &ordinal);
3199 .struct_span_err(attr.span, &msg)
3200 .note("the value may not exceed `u16::MAX`")
3206 .struct_span_err(attr.span, "illegal ordinal format in `link_ordinal`")
3207 .note("an unsuffixed integer value, e.g., `1`, is expected")
3213 fn check_link_name_xor_ordinal(
3215 codegen_fn_attrs: &CodegenFnAttrs,
3216 inline_span: Option<Span>,
3218 if codegen_fn_attrs.link_name.is_none() || codegen_fn_attrs.link_ordinal.is_none() {
3221 let msg = "cannot use `#[link_name]` with `#[link_ordinal]`";
3222 if let Some(span) = inline_span {
3223 tcx.sess.span_err(span, msg);
3229 /// Checks the function annotated with `#[target_feature]` is not a safe
3230 /// trait method implementation, reporting an error if it is.
3231 fn check_target_feature_trait_unsafe(tcx: TyCtxt<'_>, id: LocalDefId, attr_span: Span) {
3232 let hir_id = tcx.hir().local_def_id_to_hir_id(id);
3233 let node = tcx.hir().get(hir_id);
3234 if let Node::ImplItem(hir::ImplItem { kind: hir::ImplItemKind::Fn(..), .. }) = node {
3235 let parent_id = tcx.hir().get_parent_did(hir_id);
3236 let parent_item = tcx.hir().expect_item(parent_id);
3237 if let hir::ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }) = parent_item.kind {
3241 "`#[target_feature(..)]` cannot be applied to safe trait method",
3243 .span_label(attr_span, "cannot be applied to safe trait method")
3244 .span_label(tcx.def_span(id), "not an `unsafe` function")