1 // ignore-tidy-filelength
2 //! "Collection" is the process of determining the type and other external
3 //! details of each item in Rust. Collection is specifically concerned
4 //! with *inter-procedural* things -- for example, for a function
5 //! definition, collection will figure out the type and signature of the
6 //! function, but it will not visit the *body* of the function in any way,
7 //! nor examine type annotations on local variables (that's the job of
10 //! Collecting is ultimately defined by a bundle of queries that
11 //! inquire after various facts about the items in the crate (e.g.,
12 //! `type_of`, `generics_of`, `predicates_of`, etc). See the `provide` function
15 //! At present, however, we do run collection across all items in the
16 //! crate as a kind of pass. This should eventually be factored away.
18 // ignore-tidy-filelength
20 use crate::astconv::{AstConv, SizedByDefault};
21 use crate::bounds::Bounds;
22 use crate::check::intrinsic::intrinsic_operation_unsafety;
23 use crate::constrained_generic_params as cgp;
25 use crate::middle::resolve_lifetime as rl;
27 use rustc_ast::{MetaItemKind, NestedMetaItem};
28 use rustc_attr::{list_contains_name, InlineAttr, InstructionSetAttr, OptimizeAttr};
29 use rustc_data_structures::captures::Captures;
30 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexSet};
31 use rustc_errors::{struct_span_err, Applicability};
33 use rustc_hir::def::{CtorKind, DefKind, Res};
34 use rustc_hir::def_id::{DefId, LocalDefId, LOCAL_CRATE};
35 use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
36 use rustc_hir::weak_lang_items;
37 use rustc_hir::{GenericParamKind, HirId, Node};
38 use rustc_middle::hir::map::blocks::FnLikeNode;
39 use rustc_middle::hir::map::Map;
40 use rustc_middle::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs};
41 use rustc_middle::mir::mono::Linkage;
42 use rustc_middle::ty::query::Providers;
43 use rustc_middle::ty::subst::InternalSubsts;
44 use rustc_middle::ty::util::Discr;
45 use rustc_middle::ty::util::IntTypeExt;
46 use rustc_middle::ty::{self, AdtKind, Const, DefIdTree, ToPolyTraitRef, Ty, TyCtxt};
47 use rustc_middle::ty::{ReprOptions, ToPredicate, WithConstness};
48 use rustc_session::lint;
49 use rustc_session::parse::feature_err;
50 use rustc_span::symbol::{kw, sym, Ident, Symbol};
51 use rustc_span::{Span, DUMMY_SP};
52 use rustc_target::spec::{abi, SanitizerSet};
53 use rustc_trait_selection::traits::error_reporting::suggestions::NextTypeParamName;
59 struct OnlySelfBounds(bool);
61 ///////////////////////////////////////////////////////////////////////////
64 fn collect_mod_item_types(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
65 tcx.hir().visit_item_likes_in_module(
67 &mut CollectItemTypesVisitor { tcx }.as_deep_visitor(),
71 pub fn provide(providers: &mut Providers) {
72 *providers = Providers {
73 opt_const_param_of: type_of::opt_const_param_of,
74 type_of: type_of::type_of,
75 item_bounds: item_bounds::item_bounds,
76 explicit_item_bounds: item_bounds::explicit_item_bounds,
79 predicates_defined_on,
80 projection_ty_from_predicates,
81 explicit_predicates_of,
83 super_predicates_that_define_assoc_type,
84 trait_explicit_predicates_and_bounds,
85 type_param_predicates,
95 collect_mod_item_types,
100 ///////////////////////////////////////////////////////////////////////////
102 /// Context specific to some particular item. This is what implements
103 /// `AstConv`. It has information about the predicates that are defined
104 /// on the trait. Unfortunately, this predicate information is
105 /// available in various different forms at various points in the
106 /// process. So we can't just store a pointer to e.g., the AST or the
107 /// parsed ty form, we have to be more flexible. To this end, the
108 /// `ItemCtxt` is parameterized by a `DefId` that it uses to satisfy
109 /// `get_type_parameter_bounds` requests, drawing the information from
110 /// the AST (`hir::Generics`), recursively.
111 pub struct ItemCtxt<'tcx> {
116 ///////////////////////////////////////////////////////////////////////////
119 crate struct PlaceholderHirTyCollector(crate Vec<Span>);
121 impl<'v> Visitor<'v> for PlaceholderHirTyCollector {
122 type Map = intravisit::ErasedMap<'v>;
124 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
125 NestedVisitorMap::None
127 fn visit_ty(&mut self, t: &'v hir::Ty<'v>) {
128 if let hir::TyKind::Infer = t.kind {
131 intravisit::walk_ty(self, t)
135 struct CollectItemTypesVisitor<'tcx> {
139 /// If there are any placeholder types (`_`), emit an error explaining that this is not allowed
140 /// and suggest adding type parameters in the appropriate place, taking into consideration any and
141 /// all already existing generic type parameters to avoid suggesting a name that is already in use.
142 crate fn placeholder_type_error(
145 generics: &[hir::GenericParam<'_>],
146 placeholder_types: Vec<Span>,
148 hir_ty: Option<&hir::Ty<'_>>,
150 if placeholder_types.is_empty() {
154 let type_name = generics.next_type_param_name(None);
155 let mut sugg: Vec<_> =
156 placeholder_types.iter().map(|sp| (*sp, (*type_name).to_string())).collect();
158 if generics.is_empty() {
159 if let Some(span) = span {
160 sugg.push((span, format!("<{}>", type_name)));
162 } else if let Some(arg) = generics
164 .find(|arg| matches!(arg.name, hir::ParamName::Plain(Ident { name: kw::Underscore, .. })))
166 // Account for `_` already present in cases like `struct S<_>(_);` and suggest
167 // `struct S<T>(T);` instead of `struct S<_, T>(T);`.
168 sugg.push((arg.span, (*type_name).to_string()));
170 let last = generics.iter().last().unwrap();
172 // Account for bounds, we want `fn foo<T: E, K>(_: K)` not `fn foo<T, K: E>(_: K)`.
173 last.bounds_span().unwrap_or(last.span).shrink_to_hi(),
174 format!(", {}", type_name),
178 let mut err = bad_placeholder_type(tcx, placeholder_types);
180 // Suggest, but only if it is not a function in const or static
182 let mut is_fn = false;
183 let mut is_const = false;
184 let mut is_static = false;
186 if let Some(hir_ty) = hir_ty {
187 if let hir::TyKind::BareFn(_) = hir_ty.kind {
190 // Check if parent is const or static
191 let parent_id = tcx.hir().get_parent_node(hir_ty.hir_id);
192 let parent_node = tcx.hir().get(parent_id);
194 if let hir::Node::Item(item) = parent_node {
195 if let hir::ItemKind::Const(_, _) = item.kind {
197 } else if let hir::ItemKind::Static(_, _, _) = item.kind {
204 // if function is wrapped around a const or static,
205 // then don't show the suggestion
206 if !(is_fn && (is_const || is_static)) {
207 err.multipart_suggestion(
208 "use type parameters instead",
210 Applicability::HasPlaceholders,
217 fn reject_placeholder_type_signatures_in_item(tcx: TyCtxt<'tcx>, item: &'tcx hir::Item<'tcx>) {
218 let (generics, suggest) = match &item.kind {
219 hir::ItemKind::Union(_, generics)
220 | hir::ItemKind::Enum(_, generics)
221 | hir::ItemKind::TraitAlias(generics, _)
222 | hir::ItemKind::Trait(_, _, generics, ..)
223 | hir::ItemKind::Impl(hir::Impl { generics, .. })
224 | hir::ItemKind::Struct(_, generics) => (generics, true),
225 hir::ItemKind::OpaqueTy(hir::OpaqueTy { generics, .. })
226 | hir::ItemKind::TyAlias(_, generics) => (generics, false),
227 // `static`, `fn` and `const` are handled elsewhere to suggest appropriate type.
231 let mut visitor = PlaceholderHirTyCollector::default();
232 visitor.visit_item(item);
234 placeholder_type_error(tcx, Some(generics.span), generics.params, visitor.0, suggest, None);
237 impl Visitor<'tcx> for CollectItemTypesVisitor<'tcx> {
238 type Map = Map<'tcx>;
240 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
241 NestedVisitorMap::OnlyBodies(self.tcx.hir())
244 fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) {
245 convert_item(self.tcx, item.item_id());
246 reject_placeholder_type_signatures_in_item(self.tcx, item);
247 intravisit::walk_item(self, item);
250 fn visit_generics(&mut self, generics: &'tcx hir::Generics<'tcx>) {
251 for param in generics.params {
253 hir::GenericParamKind::Lifetime { .. } => {}
254 hir::GenericParamKind::Type { default: Some(_), .. } => {
255 let def_id = self.tcx.hir().local_def_id(param.hir_id);
256 self.tcx.ensure().type_of(def_id);
258 hir::GenericParamKind::Type { .. } => {}
259 hir::GenericParamKind::Const { default, .. } => {
260 let def_id = self.tcx.hir().local_def_id(param.hir_id);
261 self.tcx.ensure().type_of(def_id);
262 if let Some(default) = default {
263 let default_def_id = self.tcx.hir().local_def_id(default.hir_id);
264 // need to store default and type of default
265 self.tcx.ensure().type_of(default_def_id);
266 self.tcx.ensure().const_param_default(def_id);
271 intravisit::walk_generics(self, generics);
274 fn visit_expr(&mut self, expr: &'tcx hir::Expr<'tcx>) {
275 if let hir::ExprKind::Closure(..) = expr.kind {
276 let def_id = self.tcx.hir().local_def_id(expr.hir_id);
277 self.tcx.ensure().generics_of(def_id);
278 self.tcx.ensure().type_of(def_id);
280 intravisit::walk_expr(self, expr);
283 fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem<'tcx>) {
284 convert_trait_item(self.tcx, trait_item.trait_item_id());
285 intravisit::walk_trait_item(self, trait_item);
288 fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem<'tcx>) {
289 convert_impl_item(self.tcx, impl_item.impl_item_id());
290 intravisit::walk_impl_item(self, impl_item);
294 ///////////////////////////////////////////////////////////////////////////
295 // Utility types and common code for the above passes.
297 fn bad_placeholder_type(
299 mut spans: Vec<Span>,
300 ) -> rustc_errors::DiagnosticBuilder<'tcx> {
302 let mut err = struct_span_err!(
306 "the type placeholder `_` is not allowed within types on item signatures",
309 err.span_label(span, "not allowed in type signatures");
314 impl ItemCtxt<'tcx> {
315 pub fn new(tcx: TyCtxt<'tcx>, item_def_id: DefId) -> ItemCtxt<'tcx> {
316 ItemCtxt { tcx, item_def_id }
319 pub fn to_ty(&self, ast_ty: &hir::Ty<'_>) -> Ty<'tcx> {
320 <dyn AstConv<'_>>::ast_ty_to_ty(self, ast_ty)
323 pub fn hir_id(&self) -> hir::HirId {
324 self.tcx.hir().local_def_id_to_hir_id(self.item_def_id.expect_local())
327 pub fn node(&self) -> hir::Node<'tcx> {
328 self.tcx.hir().get(self.hir_id())
332 impl AstConv<'tcx> for ItemCtxt<'tcx> {
333 fn tcx(&self) -> TyCtxt<'tcx> {
337 fn item_def_id(&self) -> Option<DefId> {
338 Some(self.item_def_id)
341 fn default_constness_for_trait_bounds(&self) -> hir::Constness {
342 if let Some(fn_like) = FnLikeNode::from_node(self.node()) {
345 hir::Constness::NotConst
349 fn get_type_parameter_bounds(
354 ) -> ty::GenericPredicates<'tcx> {
355 self.tcx.at(span).type_param_predicates((
357 def_id.expect_local(),
362 fn re_infer(&self, _: Option<&ty::GenericParamDef>, _: Span) -> Option<ty::Region<'tcx>> {
366 fn allow_ty_infer(&self) -> bool {
370 fn ty_infer(&self, _: Option<&ty::GenericParamDef>, span: Span) -> Ty<'tcx> {
371 self.tcx().ty_error_with_message(span, "bad_placeholder_type")
377 _: Option<&ty::GenericParamDef>,
379 ) -> &'tcx Const<'tcx> {
380 bad_placeholder_type(self.tcx(), vec![span]).emit();
381 // Typeck doesn't expect erased regions to be returned from `type_of`.
382 let ty = self.tcx.fold_regions(ty, &mut false, |r, _| match r {
383 ty::ReErased => self.tcx.lifetimes.re_static,
386 self.tcx().const_error(ty)
389 fn projected_ty_from_poly_trait_ref(
393 item_segment: &hir::PathSegment<'_>,
394 poly_trait_ref: ty::PolyTraitRef<'tcx>,
396 if let Some(trait_ref) = poly_trait_ref.no_bound_vars() {
397 let item_substs = <dyn AstConv<'tcx>>::create_substs_for_associated_item(
405 self.tcx().mk_projection(item_def_id, item_substs)
407 // There are no late-bound regions; we can just ignore the binder.
408 let mut err = struct_span_err!(
412 "cannot use the associated type of a trait \
413 with uninferred generic parameters"
417 hir::Node::Field(_) | hir::Node::Ctor(_) | hir::Node::Variant(_) => {
419 self.tcx.hir().expect_item(self.tcx.hir().get_parent_item(self.hir_id()));
421 hir::ItemKind::Enum(_, generics)
422 | hir::ItemKind::Struct(_, generics)
423 | hir::ItemKind::Union(_, generics) => {
424 let lt_name = get_new_lifetime_name(self.tcx, poly_trait_ref, generics);
425 let (lt_sp, sugg) = match generics.params {
426 [] => (generics.span, format!("<{}>", lt_name)),
428 (bound.span.shrink_to_lo(), format!("{}, ", lt_name))
431 let suggestions = vec![
437 // Replace the existing lifetimes with a new named lifetime.
439 .replace_late_bound_regions(poly_trait_ref, |_| {
440 self.tcx.mk_region(ty::ReEarlyBound(
441 ty::EarlyBoundRegion {
444 name: Symbol::intern(<_name),
453 err.multipart_suggestion(
454 "use a fully qualified path with explicit lifetimes",
456 Applicability::MaybeIncorrect,
462 hir::Node::Item(hir::Item {
464 hir::ItemKind::Struct(..) | hir::ItemKind::Enum(..) | hir::ItemKind::Union(..),
468 | hir::Node::ForeignItem(_)
469 | hir::Node::TraitItem(_)
470 | hir::Node::ImplItem(_) => {
473 "use a fully qualified path with inferred lifetimes",
476 // Erase named lt, we want `<A as B<'_>::C`, not `<A as B<'a>::C`.
477 self.tcx.anonymize_late_bound_regions(poly_trait_ref).skip_binder(),
480 Applicability::MaybeIncorrect,
486 self.tcx().ty_error()
490 fn normalize_ty(&self, _span: Span, ty: Ty<'tcx>) -> Ty<'tcx> {
491 // Types in item signatures are not normalized to avoid undue dependencies.
495 fn set_tainted_by_errors(&self) {
496 // There's no obvious place to track this, so just let it go.
499 fn record_ty(&self, _hir_id: hir::HirId, _ty: Ty<'tcx>, _span: Span) {
500 // There's no place to record types from signatures?
504 /// Synthesize a new lifetime name that doesn't clash with any of the lifetimes already present.
505 fn get_new_lifetime_name<'tcx>(
507 poly_trait_ref: ty::PolyTraitRef<'tcx>,
508 generics: &hir::Generics<'tcx>,
510 let existing_lifetimes = tcx
511 .collect_referenced_late_bound_regions(&poly_trait_ref)
514 if let ty::BoundRegionKind::BrNamed(_, name) = lt {
515 Some(name.as_str().to_string())
520 .chain(generics.params.iter().filter_map(|param| {
521 if let hir::GenericParamKind::Lifetime { .. } = ¶m.kind {
522 Some(param.name.ident().as_str().to_string())
527 .collect::<FxHashSet<String>>();
529 let a_to_z_repeat_n = |n| {
530 (b'a'..=b'z').map(move |c| {
531 let mut s = '\''.to_string();
532 s.extend(std::iter::repeat(char::from(c)).take(n));
537 // If all single char lifetime names are present, we wrap around and double the chars.
538 (1..).flat_map(a_to_z_repeat_n).find(|lt| !existing_lifetimes.contains(lt.as_str())).unwrap()
541 /// Returns the predicates defined on `item_def_id` of the form
542 /// `X: Foo` where `X` is the type parameter `def_id`.
543 fn type_param_predicates(
545 (item_def_id, def_id, assoc_name): (DefId, LocalDefId, Ident),
546 ) -> ty::GenericPredicates<'_> {
549 // In the AST, bounds can derive from two places. Either
550 // written inline like `<T: Foo>` or in a where-clause like
553 let param_id = tcx.hir().local_def_id_to_hir_id(def_id);
554 let param_owner = tcx.hir().ty_param_owner(param_id);
555 let param_owner_def_id = tcx.hir().local_def_id(param_owner);
556 let generics = tcx.generics_of(param_owner_def_id);
557 let index = generics.param_def_id_to_index[&def_id.to_def_id()];
558 let ty = tcx.mk_ty_param(index, tcx.hir().ty_param_name(param_id));
560 // Don't look for bounds where the type parameter isn't in scope.
561 let parent = if item_def_id == param_owner_def_id.to_def_id() {
564 tcx.generics_of(item_def_id).parent
567 let mut result = parent
569 let icx = ItemCtxt::new(tcx, parent);
570 icx.get_type_parameter_bounds(DUMMY_SP, def_id.to_def_id(), assoc_name)
572 .unwrap_or_default();
573 let mut extend = None;
575 let item_hir_id = tcx.hir().local_def_id_to_hir_id(item_def_id.expect_local());
576 let ast_generics = match tcx.hir().get(item_hir_id) {
577 Node::TraitItem(item) => &item.generics,
579 Node::ImplItem(item) => &item.generics,
581 Node::Item(item) => {
583 ItemKind::Fn(.., ref generics, _)
584 | ItemKind::Impl(hir::Impl { ref generics, .. })
585 | ItemKind::TyAlias(_, ref generics)
586 | ItemKind::OpaqueTy(OpaqueTy { ref generics, impl_trait_fn: None, .. })
587 | ItemKind::Enum(_, ref generics)
588 | ItemKind::Struct(_, ref generics)
589 | ItemKind::Union(_, ref generics) => generics,
590 ItemKind::Trait(_, _, ref generics, ..) => {
591 // Implied `Self: Trait` and supertrait bounds.
592 if param_id == item_hir_id {
593 let identity_trait_ref = ty::TraitRef::identity(tcx, item_def_id);
595 Some((identity_trait_ref.without_const().to_predicate(tcx), item.span));
603 Node::ForeignItem(item) => match item.kind {
604 ForeignItemKind::Fn(_, _, ref generics) => generics,
611 let icx = ItemCtxt::new(tcx, item_def_id);
612 let extra_predicates = extend.into_iter().chain(
613 icx.type_parameter_bounds_in_generics(
617 OnlySelfBounds(true),
621 .filter(|(predicate, _)| match predicate.kind().skip_binder() {
622 ty::PredicateKind::Trait(data, _) => data.self_ty().is_param(index),
627 tcx.arena.alloc_from_iter(result.predicates.iter().copied().chain(extra_predicates));
631 impl ItemCtxt<'tcx> {
632 /// Finds bounds from `hir::Generics`. This requires scanning through the
633 /// AST. We do this to avoid having to convert *all* the bounds, which
634 /// would create artificial cycles. Instead, we can only convert the
635 /// bounds for a type parameter `X` if `X::Foo` is used.
636 fn type_parameter_bounds_in_generics(
638 ast_generics: &'tcx hir::Generics<'tcx>,
639 param_id: hir::HirId,
641 only_self_bounds: OnlySelfBounds,
642 assoc_name: Option<Ident>,
643 ) -> Vec<(ty::Predicate<'tcx>, Span)> {
644 let constness = self.default_constness_for_trait_bounds();
645 let from_ty_params = ast_generics
648 .filter_map(|param| match param.kind {
649 GenericParamKind::Type { .. } if param.hir_id == param_id => Some(¶m.bounds),
652 .flat_map(|bounds| bounds.iter())
653 .filter(|b| match assoc_name {
654 Some(assoc_name) => self.bound_defines_assoc_item(b, assoc_name),
657 .flat_map(|b| predicates_from_bound(self, ty, b, constness));
659 let from_where_clauses = ast_generics
663 .filter_map(|wp| match *wp {
664 hir::WherePredicate::BoundPredicate(ref bp) => Some(bp),
668 let bt = if is_param(self.tcx, &bp.bounded_ty, param_id) {
670 } else if !only_self_bounds.0 {
671 Some(self.to_ty(&bp.bounded_ty))
677 .filter(|b| match assoc_name {
678 Some(assoc_name) => self.bound_defines_assoc_item(b, assoc_name),
681 .filter_map(move |b| bt.map(|bt| (bt, b)))
683 .flat_map(|(bt, b)| predicates_from_bound(self, bt, b, constness));
685 from_ty_params.chain(from_where_clauses).collect()
688 fn bound_defines_assoc_item(&self, b: &hir::GenericBound<'_>, assoc_name: Ident) -> bool {
689 debug!("bound_defines_assoc_item(b={:?}, assoc_name={:?})", b, assoc_name);
692 hir::GenericBound::Trait(poly_trait_ref, _) => {
693 let trait_ref = &poly_trait_ref.trait_ref;
694 if let Some(trait_did) = trait_ref.trait_def_id() {
695 self.tcx.trait_may_define_assoc_type(trait_did, assoc_name)
705 /// Tests whether this is the AST for a reference to the type
706 /// parameter with ID `param_id`. We use this so as to avoid running
707 /// `ast_ty_to_ty`, because we want to avoid triggering an all-out
708 /// conversion of the type to avoid inducing unnecessary cycles.
709 fn is_param(tcx: TyCtxt<'_>, ast_ty: &hir::Ty<'_>, param_id: hir::HirId) -> bool {
710 if let hir::TyKind::Path(hir::QPath::Resolved(None, ref path)) = ast_ty.kind {
712 Res::SelfTy(Some(def_id), None) | Res::Def(DefKind::TyParam, def_id) => {
713 def_id == tcx.hir().local_def_id(param_id).to_def_id()
722 fn convert_item(tcx: TyCtxt<'_>, item_id: hir::ItemId) {
723 let it = tcx.hir().item(item_id);
724 debug!("convert: item {} with id {}", it.ident, it.hir_id());
725 let def_id = item_id.def_id;
728 // These don't define types.
729 hir::ItemKind::ExternCrate(_)
730 | hir::ItemKind::Use(..)
731 | hir::ItemKind::Mod(_)
732 | hir::ItemKind::GlobalAsm(_) => {}
733 hir::ItemKind::ForeignMod { items, .. } => {
735 let item = tcx.hir().foreign_item(item.id);
736 tcx.ensure().generics_of(item.def_id);
737 tcx.ensure().type_of(item.def_id);
738 tcx.ensure().predicates_of(item.def_id);
740 hir::ForeignItemKind::Fn(..) => tcx.ensure().fn_sig(item.def_id),
741 hir::ForeignItemKind::Static(..) => {
742 let mut visitor = PlaceholderHirTyCollector::default();
743 visitor.visit_foreign_item(item);
744 placeholder_type_error(tcx, None, &[], visitor.0, false, None);
750 hir::ItemKind::Enum(ref enum_definition, _) => {
751 tcx.ensure().generics_of(def_id);
752 tcx.ensure().type_of(def_id);
753 tcx.ensure().predicates_of(def_id);
754 convert_enum_variant_types(tcx, def_id.to_def_id(), &enum_definition.variants);
756 hir::ItemKind::Impl { .. } => {
757 tcx.ensure().generics_of(def_id);
758 tcx.ensure().type_of(def_id);
759 tcx.ensure().impl_trait_ref(def_id);
760 tcx.ensure().predicates_of(def_id);
762 hir::ItemKind::Trait(..) => {
763 tcx.ensure().generics_of(def_id);
764 tcx.ensure().trait_def(def_id);
765 tcx.at(it.span).super_predicates_of(def_id);
766 tcx.ensure().predicates_of(def_id);
768 hir::ItemKind::TraitAlias(..) => {
769 tcx.ensure().generics_of(def_id);
770 tcx.at(it.span).super_predicates_of(def_id);
771 tcx.ensure().predicates_of(def_id);
773 hir::ItemKind::Struct(ref struct_def, _) | hir::ItemKind::Union(ref struct_def, _) => {
774 tcx.ensure().generics_of(def_id);
775 tcx.ensure().type_of(def_id);
776 tcx.ensure().predicates_of(def_id);
778 for f in struct_def.fields() {
779 let def_id = tcx.hir().local_def_id(f.hir_id);
780 tcx.ensure().generics_of(def_id);
781 tcx.ensure().type_of(def_id);
782 tcx.ensure().predicates_of(def_id);
785 if let Some(ctor_hir_id) = struct_def.ctor_hir_id() {
786 convert_variant_ctor(tcx, ctor_hir_id);
790 // Desugared from `impl Trait`, so visited by the function's return type.
791 hir::ItemKind::OpaqueTy(hir::OpaqueTy { impl_trait_fn: Some(_), .. }) => {}
793 // Don't call `type_of` on opaque types, since that depends on type
794 // checking function bodies. `check_item_type` ensures that it's called
796 hir::ItemKind::OpaqueTy(..) => {
797 tcx.ensure().generics_of(def_id);
798 tcx.ensure().predicates_of(def_id);
799 tcx.ensure().explicit_item_bounds(def_id);
801 hir::ItemKind::TyAlias(..)
802 | hir::ItemKind::Static(..)
803 | hir::ItemKind::Const(..)
804 | hir::ItemKind::Fn(..) => {
805 tcx.ensure().generics_of(def_id);
806 tcx.ensure().type_of(def_id);
807 tcx.ensure().predicates_of(def_id);
809 hir::ItemKind::Fn(..) => tcx.ensure().fn_sig(def_id),
810 hir::ItemKind::OpaqueTy(..) => tcx.ensure().item_bounds(def_id),
817 fn convert_trait_item(tcx: TyCtxt<'_>, trait_item_id: hir::TraitItemId) {
818 let trait_item = tcx.hir().trait_item(trait_item_id);
819 tcx.ensure().generics_of(trait_item_id.def_id);
821 match trait_item.kind {
822 hir::TraitItemKind::Fn(..) => {
823 tcx.ensure().type_of(trait_item_id.def_id);
824 tcx.ensure().fn_sig(trait_item_id.def_id);
827 hir::TraitItemKind::Const(.., Some(_)) => {
828 tcx.ensure().type_of(trait_item_id.def_id);
831 hir::TraitItemKind::Const(..) => {
832 tcx.ensure().type_of(trait_item_id.def_id);
833 // Account for `const C: _;`.
834 let mut visitor = PlaceholderHirTyCollector::default();
835 visitor.visit_trait_item(trait_item);
836 placeholder_type_error(tcx, None, &[], visitor.0, false, None);
839 hir::TraitItemKind::Type(_, Some(_)) => {
840 tcx.ensure().item_bounds(trait_item_id.def_id);
841 tcx.ensure().type_of(trait_item_id.def_id);
842 // Account for `type T = _;`.
843 let mut visitor = PlaceholderHirTyCollector::default();
844 visitor.visit_trait_item(trait_item);
845 placeholder_type_error(tcx, None, &[], visitor.0, false, None);
848 hir::TraitItemKind::Type(_, None) => {
849 tcx.ensure().item_bounds(trait_item_id.def_id);
850 // #74612: Visit and try to find bad placeholders
851 // even if there is no concrete type.
852 let mut visitor = PlaceholderHirTyCollector::default();
853 visitor.visit_trait_item(trait_item);
855 placeholder_type_error(tcx, None, &[], visitor.0, false, None);
859 tcx.ensure().predicates_of(trait_item_id.def_id);
862 fn convert_impl_item(tcx: TyCtxt<'_>, impl_item_id: hir::ImplItemId) {
863 let def_id = impl_item_id.def_id;
864 tcx.ensure().generics_of(def_id);
865 tcx.ensure().type_of(def_id);
866 tcx.ensure().predicates_of(def_id);
867 let impl_item = tcx.hir().impl_item(impl_item_id);
868 match impl_item.kind {
869 hir::ImplItemKind::Fn(..) => {
870 tcx.ensure().fn_sig(def_id);
872 hir::ImplItemKind::TyAlias(_) => {
873 // Account for `type T = _;`
874 let mut visitor = PlaceholderHirTyCollector::default();
875 visitor.visit_impl_item(impl_item);
877 placeholder_type_error(tcx, None, &[], visitor.0, false, None);
879 hir::ImplItemKind::Const(..) => {}
883 fn convert_variant_ctor(tcx: TyCtxt<'_>, ctor_id: hir::HirId) {
884 let def_id = tcx.hir().local_def_id(ctor_id);
885 tcx.ensure().generics_of(def_id);
886 tcx.ensure().type_of(def_id);
887 tcx.ensure().predicates_of(def_id);
890 fn convert_enum_variant_types(tcx: TyCtxt<'_>, def_id: DefId, variants: &[hir::Variant<'_>]) {
891 let def = tcx.adt_def(def_id);
892 let repr_type = def.repr.discr_type();
893 let initial = repr_type.initial_discriminant(tcx);
894 let mut prev_discr = None::<Discr<'_>>;
896 // fill the discriminant values and field types
897 for variant in variants {
898 let wrapped_discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
900 if let Some(ref e) = variant.disr_expr {
901 let expr_did = tcx.hir().local_def_id(e.hir_id);
902 def.eval_explicit_discr(tcx, expr_did.to_def_id())
903 } else if let Some(discr) = repr_type.disr_incr(tcx, prev_discr) {
906 struct_span_err!(tcx.sess, variant.span, E0370, "enum discriminant overflowed")
909 format!("overflowed on value after {}", prev_discr.unwrap()),
912 "explicitly set `{} = {}` if that is desired outcome",
913 variant.ident, wrapped_discr
918 .unwrap_or(wrapped_discr),
921 for f in variant.data.fields() {
922 let def_id = tcx.hir().local_def_id(f.hir_id);
923 tcx.ensure().generics_of(def_id);
924 tcx.ensure().type_of(def_id);
925 tcx.ensure().predicates_of(def_id);
928 // Convert the ctor, if any. This also registers the variant as
930 if let Some(ctor_hir_id) = variant.data.ctor_hir_id() {
931 convert_variant_ctor(tcx, ctor_hir_id);
938 variant_did: Option<LocalDefId>,
939 ctor_did: Option<LocalDefId>,
941 discr: ty::VariantDiscr,
942 def: &hir::VariantData<'_>,
943 adt_kind: ty::AdtKind,
944 parent_did: LocalDefId,
945 ) -> ty::VariantDef {
946 let mut seen_fields: FxHashMap<Ident, Span> = Default::default();
951 let fid = tcx.hir().local_def_id(f.hir_id);
952 let dup_span = seen_fields.get(&f.ident.normalize_to_macros_2_0()).cloned();
953 if let Some(prev_span) = dup_span {
954 tcx.sess.emit_err(errors::FieldAlreadyDeclared {
960 seen_fields.insert(f.ident.normalize_to_macros_2_0(), f.span);
963 ty::FieldDef { did: fid.to_def_id(), ident: f.ident, vis: tcx.visibility(fid) }
966 let recovered = match def {
967 hir::VariantData::Struct(_, r) => *r,
972 variant_did.map(LocalDefId::to_def_id),
973 ctor_did.map(LocalDefId::to_def_id),
976 CtorKind::from_hir(def),
978 parent_did.to_def_id(),
980 adt_kind == AdtKind::Struct && tcx.has_attr(parent_did.to_def_id(), sym::non_exhaustive)
981 || variant_did.map_or(false, |variant_did| {
982 tcx.has_attr(variant_did.to_def_id(), sym::non_exhaustive)
987 fn adt_def(tcx: TyCtxt<'_>, def_id: DefId) -> &ty::AdtDef {
990 let def_id = def_id.expect_local();
991 let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
992 let item = match tcx.hir().get(hir_id) {
993 Node::Item(item) => item,
997 let repr = ReprOptions::new(tcx, def_id.to_def_id());
998 let (kind, variants) = match item.kind {
999 ItemKind::Enum(ref def, _) => {
1000 let mut distance_from_explicit = 0;
1005 let variant_did = Some(tcx.hir().local_def_id(v.id));
1007 v.data.ctor_hir_id().map(|hir_id| tcx.hir().local_def_id(hir_id));
1009 let discr = if let Some(ref e) = v.disr_expr {
1010 distance_from_explicit = 0;
1011 ty::VariantDiscr::Explicit(tcx.hir().local_def_id(e.hir_id).to_def_id())
1013 ty::VariantDiscr::Relative(distance_from_explicit)
1015 distance_from_explicit += 1;
1030 (AdtKind::Enum, variants)
1032 ItemKind::Struct(ref def, _) => {
1033 let variant_did = None::<LocalDefId>;
1034 let ctor_did = def.ctor_hir_id().map(|hir_id| tcx.hir().local_def_id(hir_id));
1036 let variants = std::iter::once(convert_variant(
1041 ty::VariantDiscr::Relative(0),
1048 (AdtKind::Struct, variants)
1050 ItemKind::Union(ref def, _) => {
1051 let variant_did = None;
1052 let ctor_did = def.ctor_hir_id().map(|hir_id| tcx.hir().local_def_id(hir_id));
1054 let variants = std::iter::once(convert_variant(
1059 ty::VariantDiscr::Relative(0),
1066 (AdtKind::Union, variants)
1070 tcx.alloc_adt_def(def_id.to_def_id(), kind, variants, repr)
1073 /// Ensures that the super-predicates of the trait with a `DefId`
1074 /// of `trait_def_id` are converted and stored. This also ensures that
1075 /// the transitive super-predicates are converted.
1076 fn super_predicates_of(tcx: TyCtxt<'_>, trait_def_id: DefId) -> ty::GenericPredicates<'_> {
1077 debug!("super_predicates(trait_def_id={:?})", trait_def_id);
1078 tcx.super_predicates_that_define_assoc_type((trait_def_id, None))
1081 /// Ensures that the super-predicates of the trait with a `DefId`
1082 /// of `trait_def_id` are converted and stored. This also ensures that
1083 /// the transitive super-predicates are converted.
1084 fn super_predicates_that_define_assoc_type(
1086 (trait_def_id, assoc_name): (DefId, Option<Ident>),
1087 ) -> ty::GenericPredicates<'_> {
1089 "super_predicates_that_define_assoc_type(trait_def_id={:?}, assoc_name={:?})",
1090 trait_def_id, assoc_name
1092 if trait_def_id.is_local() {
1093 debug!("super_predicates_that_define_assoc_type: local trait_def_id={:?}", trait_def_id);
1094 let trait_hir_id = tcx.hir().local_def_id_to_hir_id(trait_def_id.expect_local());
1096 let item = match tcx.hir().get(trait_hir_id) {
1097 Node::Item(item) => item,
1098 _ => bug!("trait_node_id {} is not an item", trait_hir_id),
1101 let (generics, bounds) = match item.kind {
1102 hir::ItemKind::Trait(.., ref generics, ref supertraits, _) => (generics, supertraits),
1103 hir::ItemKind::TraitAlias(ref generics, ref supertraits) => (generics, supertraits),
1104 _ => span_bug!(item.span, "super_predicates invoked on non-trait"),
1107 let icx = ItemCtxt::new(tcx, trait_def_id);
1109 // Convert the bounds that follow the colon, e.g., `Bar + Zed` in `trait Foo: Bar + Zed`.
1110 let self_param_ty = tcx.types.self_param;
1111 let superbounds1 = if let Some(assoc_name) = assoc_name {
1112 <dyn AstConv<'_>>::compute_bounds_that_match_assoc_type(
1121 <dyn AstConv<'_>>::compute_bounds(
1130 let superbounds1 = superbounds1.predicates(tcx, self_param_ty);
1132 // Convert any explicit superbounds in the where-clause,
1133 // e.g., `trait Foo where Self: Bar`.
1134 // In the case of trait aliases, however, we include all bounds in the where-clause,
1135 // so e.g., `trait Foo = where u32: PartialEq<Self>` would include `u32: PartialEq<Self>`
1136 // as one of its "superpredicates".
1137 let is_trait_alias = tcx.is_trait_alias(trait_def_id);
1138 let superbounds2 = icx.type_parameter_bounds_in_generics(
1142 OnlySelfBounds(!is_trait_alias),
1146 // Combine the two lists to form the complete set of superbounds:
1147 let superbounds = &*tcx.arena.alloc_from_iter(superbounds1.into_iter().chain(superbounds2));
1149 // Now require that immediate supertraits are converted,
1150 // which will, in turn, reach indirect supertraits.
1151 if assoc_name.is_none() {
1152 // Now require that immediate supertraits are converted,
1153 // which will, in turn, reach indirect supertraits.
1154 for &(pred, span) in superbounds {
1155 debug!("superbound: {:?}", pred);
1156 if let ty::PredicateKind::Trait(bound, _) = pred.kind().skip_binder() {
1157 tcx.at(span).super_predicates_of(bound.def_id());
1162 ty::GenericPredicates { parent: None, predicates: superbounds }
1164 // if `assoc_name` is None, then the query should've been redirected to an
1165 // external provider
1166 assert!(assoc_name.is_some());
1167 tcx.super_predicates_of(trait_def_id)
1171 fn trait_def(tcx: TyCtxt<'_>, def_id: DefId) -> ty::TraitDef {
1172 let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
1173 let item = tcx.hir().expect_item(hir_id);
1175 let (is_auto, unsafety) = match item.kind {
1176 hir::ItemKind::Trait(is_auto, unsafety, ..) => (is_auto == hir::IsAuto::Yes, unsafety),
1177 hir::ItemKind::TraitAlias(..) => (false, hir::Unsafety::Normal),
1178 _ => span_bug!(item.span, "trait_def_of_item invoked on non-trait"),
1181 let paren_sugar = tcx.has_attr(def_id, sym::rustc_paren_sugar);
1182 if paren_sugar && !tcx.features().unboxed_closures {
1186 "the `#[rustc_paren_sugar]` attribute is a temporary means of controlling \
1187 which traits can use parenthetical notation",
1189 .help("add `#![feature(unboxed_closures)]` to the crate attributes to use it")
1193 let is_marker = tcx.has_attr(def_id, sym::marker);
1194 let skip_array_during_method_dispatch =
1195 tcx.has_attr(def_id, sym::rustc_skip_array_during_method_dispatch);
1196 let spec_kind = if tcx.has_attr(def_id, sym::rustc_unsafe_specialization_marker) {
1197 ty::trait_def::TraitSpecializationKind::Marker
1198 } else if tcx.has_attr(def_id, sym::rustc_specialization_trait) {
1199 ty::trait_def::TraitSpecializationKind::AlwaysApplicable
1201 ty::trait_def::TraitSpecializationKind::None
1203 let def_path_hash = tcx.def_path_hash(def_id);
1210 skip_array_during_method_dispatch,
1216 fn has_late_bound_regions<'tcx>(tcx: TyCtxt<'tcx>, node: Node<'tcx>) -> Option<Span> {
1217 struct LateBoundRegionsDetector<'tcx> {
1219 outer_index: ty::DebruijnIndex,
1220 has_late_bound_regions: Option<Span>,
1223 impl Visitor<'tcx> for LateBoundRegionsDetector<'tcx> {
1224 type Map = intravisit::ErasedMap<'tcx>;
1226 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
1227 NestedVisitorMap::None
1230 fn visit_ty(&mut self, ty: &'tcx hir::Ty<'tcx>) {
1231 if self.has_late_bound_regions.is_some() {
1235 hir::TyKind::BareFn(..) => {
1236 self.outer_index.shift_in(1);
1237 intravisit::walk_ty(self, ty);
1238 self.outer_index.shift_out(1);
1240 _ => intravisit::walk_ty(self, ty),
1244 fn visit_poly_trait_ref(
1246 tr: &'tcx hir::PolyTraitRef<'tcx>,
1247 m: hir::TraitBoundModifier,
1249 if self.has_late_bound_regions.is_some() {
1252 self.outer_index.shift_in(1);
1253 intravisit::walk_poly_trait_ref(self, tr, m);
1254 self.outer_index.shift_out(1);
1257 fn visit_lifetime(&mut self, lt: &'tcx hir::Lifetime) {
1258 if self.has_late_bound_regions.is_some() {
1262 match self.tcx.named_region(lt.hir_id) {
1263 Some(rl::Region::Static | rl::Region::EarlyBound(..)) => {}
1265 rl::Region::LateBound(debruijn, _, _, _)
1266 | rl::Region::LateBoundAnon(debruijn, _, _),
1267 ) if debruijn < self.outer_index => {}
1269 rl::Region::LateBound(..)
1270 | rl::Region::LateBoundAnon(..)
1271 | rl::Region::Free(..),
1274 self.has_late_bound_regions = Some(lt.span);
1280 fn has_late_bound_regions<'tcx>(
1282 generics: &'tcx hir::Generics<'tcx>,
1283 decl: &'tcx hir::FnDecl<'tcx>,
1285 let mut visitor = LateBoundRegionsDetector {
1287 outer_index: ty::INNERMOST,
1288 has_late_bound_regions: None,
1290 for param in generics.params {
1291 if let GenericParamKind::Lifetime { .. } = param.kind {
1292 if tcx.is_late_bound(param.hir_id) {
1293 return Some(param.span);
1297 visitor.visit_fn_decl(decl);
1298 visitor.has_late_bound_regions
1302 Node::TraitItem(item) => match item.kind {
1303 hir::TraitItemKind::Fn(ref sig, _) => {
1304 has_late_bound_regions(tcx, &item.generics, &sig.decl)
1308 Node::ImplItem(item) => match item.kind {
1309 hir::ImplItemKind::Fn(ref sig, _) => {
1310 has_late_bound_regions(tcx, &item.generics, &sig.decl)
1314 Node::ForeignItem(item) => match item.kind {
1315 hir::ForeignItemKind::Fn(ref fn_decl, _, ref generics) => {
1316 has_late_bound_regions(tcx, generics, fn_decl)
1320 Node::Item(item) => match item.kind {
1321 hir::ItemKind::Fn(ref sig, .., ref generics, _) => {
1322 has_late_bound_regions(tcx, generics, &sig.decl)
1330 struct AnonConstInParamTyDetector {
1332 found_anon_const_in_param_ty: bool,
1336 impl<'v> Visitor<'v> for AnonConstInParamTyDetector {
1337 type Map = intravisit::ErasedMap<'v>;
1339 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
1340 NestedVisitorMap::None
1343 fn visit_generic_param(&mut self, p: &'v hir::GenericParam<'v>) {
1344 if let GenericParamKind::Const { ref ty, default: _ } = p.kind {
1345 let prev = self.in_param_ty;
1346 self.in_param_ty = true;
1348 self.in_param_ty = prev;
1352 fn visit_anon_const(&mut self, c: &'v hir::AnonConst) {
1353 if self.in_param_ty && self.ct == c.hir_id {
1354 self.found_anon_const_in_param_ty = true;
1356 intravisit::walk_anon_const(self, c)
1361 fn generics_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::Generics {
1364 let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
1366 let node = tcx.hir().get(hir_id);
1367 let parent_def_id = match node {
1369 | Node::TraitItem(_)
1372 | Node::Field(_) => {
1373 let parent_id = tcx.hir().get_parent_item(hir_id);
1374 Some(tcx.hir().local_def_id(parent_id).to_def_id())
1376 // FIXME(#43408) always enable this once `lazy_normalization` is
1377 // stable enough and does not need a feature gate anymore.
1378 Node::AnonConst(_) => {
1379 let parent_id = tcx.hir().get_parent_item(hir_id);
1380 let parent_def_id = tcx.hir().local_def_id(parent_id);
1382 let mut in_param_ty = false;
1383 for (_parent, node) in tcx.hir().parent_iter(hir_id) {
1384 if let Some(generics) = node.generics() {
1385 let mut visitor = AnonConstInParamTyDetector {
1387 found_anon_const_in_param_ty: false,
1391 visitor.visit_generics(generics);
1392 in_param_ty = visitor.found_anon_const_in_param_ty;
1398 // We do not allow generic parameters in anon consts if we are inside
1399 // of a const parameter type, e.g. `struct Foo<const N: usize, const M: [u8; N]>` is not allowed.
1401 } else if tcx.lazy_normalization() {
1402 // HACK(eddyb) this provides the correct generics when
1403 // `feature(const_generics)` is enabled, so that const expressions
1404 // used with const generics, e.g. `Foo<{N+1}>`, can work at all.
1406 // Note that we do not supply the parent generics when using
1407 // `min_const_generics`.
1408 Some(parent_def_id.to_def_id())
1410 let parent_node = tcx.hir().get(tcx.hir().get_parent_node(hir_id));
1412 // HACK(eddyb) this provides the correct generics for repeat
1413 // expressions' count (i.e. `N` in `[x; N]`), and explicit
1414 // `enum` discriminants (i.e. `D` in `enum Foo { Bar = D }`),
1415 // as they shouldn't be able to cause query cycle errors.
1416 Node::Expr(&Expr { kind: ExprKind::Repeat(_, ref constant), .. })
1417 | Node::Variant(Variant { disr_expr: Some(ref constant), .. })
1418 if constant.hir_id == hir_id =>
1420 Some(parent_def_id.to_def_id())
1427 Node::Expr(&hir::Expr { kind: hir::ExprKind::Closure(..), .. }) => {
1428 Some(tcx.closure_base_def_id(def_id))
1430 Node::Item(item) => match item.kind {
1431 ItemKind::OpaqueTy(hir::OpaqueTy { impl_trait_fn, .. }) => {
1432 impl_trait_fn.or_else(|| {
1433 let parent_id = tcx.hir().get_parent_item(hir_id);
1434 assert!(parent_id != hir_id && parent_id != CRATE_HIR_ID);
1435 debug!("generics_of: parent of opaque ty {:?} is {:?}", def_id, parent_id);
1436 // Opaque types are always nested within another item, and
1437 // inherit the generics of the item.
1438 Some(tcx.hir().local_def_id(parent_id).to_def_id())
1446 let mut opt_self = None;
1447 let mut allow_defaults = false;
1449 let no_generics = hir::Generics::empty();
1450 let ast_generics = match node {
1451 Node::TraitItem(item) => &item.generics,
1453 Node::ImplItem(item) => &item.generics,
1455 Node::Item(item) => {
1457 ItemKind::Fn(.., ref generics, _)
1458 | ItemKind::Impl(hir::Impl { ref generics, .. }) => generics,
1460 ItemKind::TyAlias(_, ref generics)
1461 | ItemKind::Enum(_, ref generics)
1462 | ItemKind::Struct(_, ref generics)
1463 | ItemKind::OpaqueTy(hir::OpaqueTy { ref generics, .. })
1464 | ItemKind::Union(_, ref generics) => {
1465 allow_defaults = true;
1469 ItemKind::Trait(_, _, ref generics, ..)
1470 | ItemKind::TraitAlias(ref generics, ..) => {
1471 // Add in the self type parameter.
1473 // Something of a hack: use the node id for the trait, also as
1474 // the node id for the Self type parameter.
1475 let param_id = item.def_id;
1477 opt_self = Some(ty::GenericParamDef {
1479 name: kw::SelfUpper,
1480 def_id: param_id.to_def_id(),
1481 pure_wrt_drop: false,
1482 kind: ty::GenericParamDefKind::Type {
1484 object_lifetime_default: rl::Set1::Empty,
1489 allow_defaults = true;
1497 Node::ForeignItem(item) => match item.kind {
1498 ForeignItemKind::Static(..) => &no_generics,
1499 ForeignItemKind::Fn(_, _, ref generics) => generics,
1500 ForeignItemKind::Type => &no_generics,
1506 let has_self = opt_self.is_some();
1507 let mut parent_has_self = false;
1508 let mut own_start = has_self as u32;
1509 let parent_count = parent_def_id.map_or(0, |def_id| {
1510 let generics = tcx.generics_of(def_id);
1511 assert_eq!(has_self, false);
1512 parent_has_self = generics.has_self;
1513 own_start = generics.count() as u32;
1514 generics.parent_count + generics.params.len()
1517 let mut params: Vec<_> = Vec::with_capacity(ast_generics.params.len() + has_self as usize);
1519 if let Some(opt_self) = opt_self {
1520 params.push(opt_self);
1523 let early_lifetimes = early_bound_lifetimes_from_generics(tcx, ast_generics);
1524 params.extend(early_lifetimes.enumerate().map(|(i, param)| ty::GenericParamDef {
1525 name: param.name.ident().name,
1526 index: own_start + i as u32,
1527 def_id: tcx.hir().local_def_id(param.hir_id).to_def_id(),
1528 pure_wrt_drop: param.pure_wrt_drop,
1529 kind: ty::GenericParamDefKind::Lifetime,
1532 let object_lifetime_defaults = tcx.object_lifetime_defaults(hir_id);
1534 // Now create the real type and const parameters.
1535 let type_start = own_start - has_self as u32 + params.len() as u32;
1538 params.extend(ast_generics.params.iter().filter_map(|param| match param.kind {
1539 GenericParamKind::Lifetime { .. } => None,
1540 GenericParamKind::Type { ref default, synthetic, .. } => {
1541 if !allow_defaults && default.is_some() {
1542 if !tcx.features().default_type_parameter_fallback {
1543 tcx.struct_span_lint_hir(
1544 lint::builtin::INVALID_TYPE_PARAM_DEFAULT,
1549 "defaults for type parameters are only allowed in \
1550 `struct`, `enum`, `type`, or `trait` definitions",
1558 let kind = ty::GenericParamDefKind::Type {
1559 has_default: default.is_some(),
1560 object_lifetime_default: object_lifetime_defaults
1562 .map_or(rl::Set1::Empty, |o| o[i]),
1566 let param_def = ty::GenericParamDef {
1567 index: type_start + i as u32,
1568 name: param.name.ident().name,
1569 def_id: tcx.hir().local_def_id(param.hir_id).to_def_id(),
1570 pure_wrt_drop: param.pure_wrt_drop,
1576 GenericParamKind::Const { default, .. } => {
1577 if !allow_defaults && default.is_some() {
1580 "defaults for const parameters are only allowed in \
1581 `struct`, `enum`, `type`, or `trait` definitions",
1585 let param_def = ty::GenericParamDef {
1586 index: type_start + i as u32,
1587 name: param.name.ident().name,
1588 def_id: tcx.hir().local_def_id(param.hir_id).to_def_id(),
1589 pure_wrt_drop: param.pure_wrt_drop,
1590 kind: ty::GenericParamDefKind::Const { has_default: default.is_some() },
1597 // provide junk type parameter defs - the only place that
1598 // cares about anything but the length is instantiation,
1599 // and we don't do that for closures.
1600 if let Node::Expr(&hir::Expr { kind: hir::ExprKind::Closure(.., gen), .. }) = node {
1601 let dummy_args = if gen.is_some() {
1602 &["<resume_ty>", "<yield_ty>", "<return_ty>", "<witness>", "<upvars>"][..]
1604 &["<closure_kind>", "<closure_signature>", "<upvars>"][..]
1607 params.extend(dummy_args.iter().enumerate().map(|(i, &arg)| ty::GenericParamDef {
1608 index: type_start + i as u32,
1609 name: Symbol::intern(arg),
1611 pure_wrt_drop: false,
1612 kind: ty::GenericParamDefKind::Type {
1614 object_lifetime_default: rl::Set1::Empty,
1620 let param_def_id_to_index = params.iter().map(|param| (param.def_id, param.index)).collect();
1623 parent: parent_def_id,
1626 param_def_id_to_index,
1627 has_self: has_self || parent_has_self,
1628 has_late_bound_regions: has_late_bound_regions(tcx, node),
1632 fn are_suggestable_generic_args(generic_args: &[hir::GenericArg<'_>]) -> bool {
1635 .filter_map(|arg| match arg {
1636 hir::GenericArg::Type(ty) => Some(ty),
1639 .any(is_suggestable_infer_ty)
1642 /// Whether `ty` is a type with `_` placeholders that can be inferred. Used in diagnostics only to
1643 /// use inference to provide suggestions for the appropriate type if possible.
1644 fn is_suggestable_infer_ty(ty: &hir::Ty<'_>) -> bool {
1648 Slice(ty) | Array(ty, _) => is_suggestable_infer_ty(ty),
1649 Tup(tys) => tys.iter().any(is_suggestable_infer_ty),
1650 Ptr(mut_ty) | Rptr(_, mut_ty) => is_suggestable_infer_ty(mut_ty.ty),
1651 OpaqueDef(_, generic_args) => are_suggestable_generic_args(generic_args),
1652 Path(hir::QPath::TypeRelative(ty, segment)) => {
1653 is_suggestable_infer_ty(ty) || are_suggestable_generic_args(segment.args().args)
1655 Path(hir::QPath::Resolved(ty_opt, hir::Path { segments, .. })) => {
1656 ty_opt.map_or(false, is_suggestable_infer_ty)
1657 || segments.iter().any(|segment| are_suggestable_generic_args(segment.args().args))
1663 pub fn get_infer_ret_ty(output: &'hir hir::FnRetTy<'hir>) -> Option<&'hir hir::Ty<'hir>> {
1664 if let hir::FnRetTy::Return(ref ty) = output {
1665 if is_suggestable_infer_ty(ty) {
1672 fn fn_sig(tcx: TyCtxt<'_>, def_id: DefId) -> ty::PolyFnSig<'_> {
1673 use rustc_hir::Node::*;
1676 let def_id = def_id.expect_local();
1677 let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
1679 let icx = ItemCtxt::new(tcx, def_id.to_def_id());
1681 match tcx.hir().get(hir_id) {
1682 TraitItem(hir::TraitItem {
1683 kind: TraitItemKind::Fn(sig, TraitFn::Provided(_)),
1688 | ImplItem(hir::ImplItem { kind: ImplItemKind::Fn(sig, _), ident, generics, .. })
1689 | Item(hir::Item { kind: ItemKind::Fn(sig, generics, _), ident, .. }) => {
1690 match get_infer_ret_ty(&sig.decl.output) {
1692 let fn_sig = tcx.typeck(def_id).liberated_fn_sigs()[hir_id];
1693 // Typeck doesn't expect erased regions to be returned from `type_of`.
1694 let fn_sig = tcx.fold_regions(fn_sig, &mut false, |r, _| match r {
1695 ty::ReErased => tcx.lifetimes.re_static,
1699 let mut visitor = PlaceholderHirTyCollector::default();
1700 visitor.visit_ty(ty);
1701 let mut diag = bad_placeholder_type(tcx, visitor.0);
1702 let ret_ty = fn_sig.output();
1703 if ret_ty != tcx.ty_error() {
1704 if !ret_ty.is_closure() {
1705 let ret_ty_str = match ret_ty.kind() {
1706 // Suggest a function pointer return type instead of a unique function definition
1707 // (e.g. `fn() -> i32` instead of `fn() -> i32 { f }`, the latter of which is invalid
1709 ty::FnDef(..) => ret_ty.fn_sig(tcx).to_string(),
1710 _ => ret_ty.to_string(),
1712 diag.span_suggestion(
1714 "replace with the correct return type",
1716 Applicability::MaybeIncorrect,
1719 // We're dealing with a closure, so we should suggest using `impl Fn` or trait bounds
1720 // to prevent the user from getting a papercut while trying to use the unique closure
1721 // syntax (e.g. `[closure@src/lib.rs:2:5: 2:9]`).
1722 diag.help("consider using an `Fn`, `FnMut`, or `FnOnce` trait bound");
1723 diag.note("for more information on `Fn` traits and closure types, see https://doc.rust-lang.org/book/ch13-01-closures.html");
1728 ty::Binder::bind(fn_sig, tcx)
1730 None => <dyn AstConv<'_>>::ty_of_fn(
1733 sig.header.unsafety,
1743 TraitItem(hir::TraitItem {
1744 kind: TraitItemKind::Fn(FnSig { header, decl, span: _ }, _),
1748 }) => <dyn AstConv<'_>>::ty_of_fn(
1759 ForeignItem(&hir::ForeignItem {
1760 kind: ForeignItemKind::Fn(ref fn_decl, _, _),
1764 let abi = tcx.hir().get_foreign_abi(hir_id);
1765 compute_sig_of_foreign_fn_decl(tcx, def_id.to_def_id(), fn_decl, abi, ident)
1768 Ctor(data) | Variant(hir::Variant { data, .. }) if data.ctor_hir_id().is_some() => {
1769 let ty = tcx.type_of(tcx.hir().get_parent_did(hir_id).to_def_id());
1771 data.fields().iter().map(|f| tcx.type_of(tcx.hir().local_def_id(f.hir_id)));
1773 tcx.mk_fn_sig(inputs, ty, false, hir::Unsafety::Normal, abi::Abi::Rust),
1778 Expr(&hir::Expr { kind: hir::ExprKind::Closure(..), .. }) => {
1779 // Closure signatures are not like other function
1780 // signatures and cannot be accessed through `fn_sig`. For
1781 // example, a closure signature excludes the `self`
1782 // argument. In any case they are embedded within the
1783 // closure type as part of the `ClosureSubsts`.
1785 // To get the signature of a closure, you should use the
1786 // `sig` method on the `ClosureSubsts`:
1788 // substs.as_closure().sig(def_id, tcx)
1790 "to get the signature of a closure, use `substs.as_closure().sig()` not `fn_sig()`",
1795 bug!("unexpected sort of node in fn_sig(): {:?}", x);
1800 fn impl_trait_ref(tcx: TyCtxt<'_>, def_id: DefId) -> Option<ty::TraitRef<'_>> {
1801 let icx = ItemCtxt::new(tcx, def_id);
1803 let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
1804 match tcx.hir().expect_item(hir_id).kind {
1805 hir::ItemKind::Impl(ref impl_) => impl_.of_trait.as_ref().map(|ast_trait_ref| {
1806 let selfty = tcx.type_of(def_id);
1807 <dyn AstConv<'_>>::instantiate_mono_trait_ref(&icx, ast_trait_ref, selfty)
1813 fn impl_polarity(tcx: TyCtxt<'_>, def_id: DefId) -> ty::ImplPolarity {
1814 let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
1815 let is_rustc_reservation = tcx.has_attr(def_id, sym::rustc_reservation_impl);
1816 let item = tcx.hir().expect_item(hir_id);
1818 hir::ItemKind::Impl(hir::Impl {
1819 polarity: hir::ImplPolarity::Negative(span),
1823 if is_rustc_reservation {
1824 let span = span.to(of_trait.as_ref().map_or(*span, |t| t.path.span));
1825 tcx.sess.span_err(span, "reservation impls can't be negative");
1827 ty::ImplPolarity::Negative
1829 hir::ItemKind::Impl(hir::Impl {
1830 polarity: hir::ImplPolarity::Positive,
1834 if is_rustc_reservation {
1835 tcx.sess.span_err(item.span, "reservation impls can't be inherent");
1837 ty::ImplPolarity::Positive
1839 hir::ItemKind::Impl(hir::Impl {
1840 polarity: hir::ImplPolarity::Positive,
1844 if is_rustc_reservation {
1845 ty::ImplPolarity::Reservation
1847 ty::ImplPolarity::Positive
1850 item => bug!("impl_polarity: {:?} not an impl", item),
1854 /// Returns the early-bound lifetimes declared in this generics
1855 /// listing. For anything other than fns/methods, this is just all
1856 /// the lifetimes that are declared. For fns or methods, we have to
1857 /// screen out those that do not appear in any where-clauses etc using
1858 /// `resolve_lifetime::early_bound_lifetimes`.
1859 fn early_bound_lifetimes_from_generics<'a, 'tcx: 'a>(
1861 generics: &'a hir::Generics<'a>,
1862 ) -> impl Iterator<Item = &'a hir::GenericParam<'a>> + Captures<'tcx> {
1863 generics.params.iter().filter(move |param| match param.kind {
1864 GenericParamKind::Lifetime { .. } => !tcx.is_late_bound(param.hir_id),
1869 /// Returns a list of type predicates for the definition with ID `def_id`, including inferred
1870 /// lifetime constraints. This includes all predicates returned by `explicit_predicates_of`, plus
1871 /// inferred constraints concerning which regions outlive other regions.
1872 fn predicates_defined_on(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicates<'_> {
1873 debug!("predicates_defined_on({:?})", def_id);
1874 let mut result = tcx.explicit_predicates_of(def_id);
1875 debug!("predicates_defined_on: explicit_predicates_of({:?}) = {:?}", def_id, result,);
1876 let inferred_outlives = tcx.inferred_outlives_of(def_id);
1877 if !inferred_outlives.is_empty() {
1879 "predicates_defined_on: inferred_outlives_of({:?}) = {:?}",
1880 def_id, inferred_outlives,
1882 if result.predicates.is_empty() {
1883 result.predicates = inferred_outlives;
1885 result.predicates = tcx
1887 .alloc_from_iter(result.predicates.iter().chain(inferred_outlives).copied());
1891 debug!("predicates_defined_on({:?}) = {:?}", def_id, result);
1895 /// Returns a list of all type predicates (explicit and implicit) for the definition with
1896 /// ID `def_id`. This includes all predicates returned by `predicates_defined_on`, plus
1897 /// `Self: Trait` predicates for traits.
1898 fn predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicates<'_> {
1899 let mut result = tcx.predicates_defined_on(def_id);
1901 if tcx.is_trait(def_id) {
1902 // For traits, add `Self: Trait` predicate. This is
1903 // not part of the predicates that a user writes, but it
1904 // is something that one must prove in order to invoke a
1905 // method or project an associated type.
1907 // In the chalk setup, this predicate is not part of the
1908 // "predicates" for a trait item. But it is useful in
1909 // rustc because if you directly (e.g.) invoke a trait
1910 // method like `Trait::method(...)`, you must naturally
1911 // prove that the trait applies to the types that were
1912 // used, and adding the predicate into this list ensures
1913 // that this is done.
1914 let span = tcx.sess.source_map().guess_head_span(tcx.def_span(def_id));
1916 tcx.arena.alloc_from_iter(result.predicates.iter().copied().chain(std::iter::once((
1917 ty::TraitRef::identity(tcx, def_id).without_const().to_predicate(tcx),
1921 debug!("predicates_of(def_id={:?}) = {:?}", def_id, result);
1925 /// Returns a list of user-specified type predicates for the definition with ID `def_id`.
1926 /// N.B., this does not include any implied/inferred constraints.
1927 fn gather_explicit_predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicates<'_> {
1930 debug!("explicit_predicates_of(def_id={:?})", def_id);
1932 let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
1933 let node = tcx.hir().get(hir_id);
1935 let mut is_trait = None;
1936 let mut is_default_impl_trait = None;
1938 let icx = ItemCtxt::new(tcx, def_id);
1939 let constness = icx.default_constness_for_trait_bounds();
1941 const NO_GENERICS: &hir::Generics<'_> = &hir::Generics::empty();
1943 // We use an `IndexSet` to preserves order of insertion.
1944 // Preserving the order of insertion is important here so as not to break UI tests.
1945 let mut predicates: FxIndexSet<(ty::Predicate<'_>, Span)> = FxIndexSet::default();
1947 let ast_generics = match node {
1948 Node::TraitItem(item) => &item.generics,
1950 Node::ImplItem(item) => &item.generics,
1952 Node::Item(item) => {
1954 ItemKind::Impl(ref impl_) => {
1955 if impl_.defaultness.is_default() {
1956 is_default_impl_trait = tcx.impl_trait_ref(def_id);
1960 ItemKind::Fn(.., ref generics, _)
1961 | ItemKind::TyAlias(_, ref generics)
1962 | ItemKind::Enum(_, ref generics)
1963 | ItemKind::Struct(_, ref generics)
1964 | ItemKind::Union(_, ref generics) => generics,
1966 ItemKind::Trait(_, _, ref generics, ..) => {
1967 is_trait = Some(ty::TraitRef::identity(tcx, def_id));
1970 ItemKind::TraitAlias(ref generics, _) => {
1971 is_trait = Some(ty::TraitRef::identity(tcx, def_id));
1974 ItemKind::OpaqueTy(OpaqueTy {
1980 if impl_trait_fn.is_some() {
1981 // return-position impl trait
1983 // We don't inherit predicates from the parent here:
1984 // If we have, say `fn f<'a, T: 'a>() -> impl Sized {}`
1985 // then the return type is `f::<'static, T>::{{opaque}}`.
1987 // If we inherited the predicates of `f` then we would
1988 // require that `T: 'static` to show that the return
1989 // type is well-formed.
1991 // The only way to have something with this opaque type
1992 // is from the return type of the containing function,
1993 // which will ensure that the function's predicates
1995 return ty::GenericPredicates { parent: None, predicates: &[] };
1997 // type-alias impl trait
2006 Node::ForeignItem(item) => match item.kind {
2007 ForeignItemKind::Static(..) => NO_GENERICS,
2008 ForeignItemKind::Fn(_, _, ref generics) => generics,
2009 ForeignItemKind::Type => NO_GENERICS,
2015 let generics = tcx.generics_of(def_id);
2016 let parent_count = generics.parent_count as u32;
2017 let has_own_self = generics.has_self && parent_count == 0;
2019 // Below we'll consider the bounds on the type parameters (including `Self`)
2020 // and the explicit where-clauses, but to get the full set of predicates
2021 // on a trait we need to add in the supertrait bounds and bounds found on
2022 // associated types.
2023 if let Some(_trait_ref) = is_trait {
2024 predicates.extend(tcx.super_predicates_of(def_id).predicates.iter().cloned());
2027 // In default impls, we can assume that the self type implements
2028 // the trait. So in:
2030 // default impl Foo for Bar { .. }
2032 // we add a default where clause `Foo: Bar`. We do a similar thing for traits
2033 // (see below). Recall that a default impl is not itself an impl, but rather a
2034 // set of defaults that can be incorporated into another impl.
2035 if let Some(trait_ref) = is_default_impl_trait {
2037 trait_ref.to_poly_trait_ref().without_const().to_predicate(tcx),
2038 tcx.def_span(def_id),
2042 // Collect the region predicates that were declared inline as
2043 // well. In the case of parameters declared on a fn or method, we
2044 // have to be careful to only iterate over early-bound regions.
2045 let mut index = parent_count + has_own_self as u32;
2046 for param in early_bound_lifetimes_from_generics(tcx, ast_generics) {
2047 let region = tcx.mk_region(ty::ReEarlyBound(ty::EarlyBoundRegion {
2048 def_id: tcx.hir().local_def_id(param.hir_id).to_def_id(),
2050 name: param.name.ident().name,
2055 GenericParamKind::Lifetime { .. } => {
2056 param.bounds.iter().for_each(|bound| match bound {
2057 hir::GenericBound::Outlives(lt) => {
2058 let bound = <dyn AstConv<'_>>::ast_region_to_region(&icx, <, None);
2059 let outlives = ty::Binder::bind(ty::OutlivesPredicate(region, bound), tcx);
2060 predicates.insert((outlives.to_predicate(tcx), lt.span));
2069 // Collect the predicates that were written inline by the user on each
2070 // type parameter (e.g., `<T: Foo>`).
2071 for param in ast_generics.params {
2073 // We already dealt with early bound lifetimes above.
2074 GenericParamKind::Lifetime { .. } => (),
2075 GenericParamKind::Type { .. } => {
2076 let name = param.name.ident().name;
2077 let param_ty = ty::ParamTy::new(index, name).to_ty(tcx);
2080 let sized = SizedByDefault::Yes;
2081 let bounds = <dyn AstConv<'_>>::compute_bounds(
2088 predicates.extend(bounds.predicates(tcx, param_ty));
2090 GenericParamKind::Const { .. } => {
2091 // Bounds on const parameters are currently not possible.
2092 debug_assert!(param.bounds.is_empty());
2098 // Add in the bounds that appear in the where-clause.
2099 let where_clause = &ast_generics.where_clause;
2100 for predicate in where_clause.predicates {
2102 hir::WherePredicate::BoundPredicate(bound_pred) => {
2103 let ty = icx.to_ty(&bound_pred.bounded_ty);
2104 let bound_vars = icx.tcx.late_bound_vars(bound_pred.bounded_ty.hir_id);
2106 // Keep the type around in a dummy predicate, in case of no bounds.
2107 // That way, `where Ty:` is not a complete noop (see #53696) and `Ty`
2108 // is still checked for WF.
2109 if bound_pred.bounds.is_empty() {
2110 if let ty::Param(_) = ty.kind() {
2111 // This is a `where T:`, which can be in the HIR from the
2112 // transformation that moves `?Sized` to `T`'s declaration.
2113 // We can skip the predicate because type parameters are
2114 // trivially WF, but also we *should*, to avoid exposing
2115 // users who never wrote `where Type:,` themselves, to
2116 // compiler/tooling bugs from not handling WF predicates.
2118 let span = bound_pred.bounded_ty.span;
2119 let re_root_empty = tcx.lifetimes.re_root_empty;
2120 let predicate = ty::Binder::bind_with_vars(
2121 ty::PredicateKind::TypeOutlives(ty::OutlivesPredicate(
2127 predicates.insert((predicate.to_predicate(tcx), span));
2131 for bound in bound_pred.bounds.iter() {
2133 hir::GenericBound::Trait(poly_trait_ref, modifier) => {
2134 let constness = match modifier {
2135 hir::TraitBoundModifier::MaybeConst => hir::Constness::NotConst,
2136 hir::TraitBoundModifier::None => constness,
2137 hir::TraitBoundModifier::Maybe => bug!("this wasn't handled"),
2140 let mut bounds = Bounds::default();
2141 let _ = <dyn AstConv<'_>>::instantiate_poly_trait_ref(
2143 &poly_trait_ref.trait_ref,
2144 poly_trait_ref.span,
2150 predicates.extend(bounds.predicates(tcx, ty));
2153 &hir::GenericBound::LangItemTrait(lang_item, span, hir_id, args) => {
2154 let mut bounds = Bounds::default();
2155 <dyn AstConv<'_>>::instantiate_lang_item_trait_ref(
2164 predicates.extend(bounds.predicates(tcx, ty));
2167 hir::GenericBound::Outlives(lifetime) => {
2169 <dyn AstConv<'_>>::ast_region_to_region(&icx, lifetime, None);
2171 ty::Binder::bind_with_vars(
2172 ty::PredicateKind::TypeOutlives(ty::OutlivesPredicate(
2185 hir::WherePredicate::RegionPredicate(region_pred) => {
2186 let r1 = <dyn AstConv<'_>>::ast_region_to_region(&icx, ®ion_pred.lifetime, None);
2187 predicates.extend(region_pred.bounds.iter().map(|bound| {
2188 let (r2, span) = match bound {
2189 hir::GenericBound::Outlives(lt) => {
2190 (<dyn AstConv<'_>>::ast_region_to_region(&icx, lt, None), lt.span)
2194 let pred = ty::PredicateKind::RegionOutlives(ty::OutlivesPredicate(r1, r2))
2195 .to_predicate(icx.tcx);
2201 hir::WherePredicate::EqPredicate(..) => {
2207 if tcx.features().const_evaluatable_checked {
2208 predicates.extend(const_evaluatable_predicates_of(tcx, def_id.expect_local()));
2211 let mut predicates: Vec<_> = predicates.into_iter().collect();
2213 // Subtle: before we store the predicates into the tcx, we
2214 // sort them so that predicates like `T: Foo<Item=U>` come
2215 // before uses of `U`. This avoids false ambiguity errors
2216 // in trait checking. See `setup_constraining_predicates`
2218 if let Node::Item(&Item { kind: ItemKind::Impl { .. }, .. }) = node {
2219 let self_ty = tcx.type_of(def_id);
2220 let trait_ref = tcx.impl_trait_ref(def_id);
2221 cgp::setup_constraining_predicates(
2225 &mut cgp::parameters_for_impl(self_ty, trait_ref),
2229 let result = ty::GenericPredicates {
2230 parent: generics.parent,
2231 predicates: tcx.arena.alloc_from_iter(predicates),
2233 debug!("explicit_predicates_of(def_id={:?}) = {:?}", def_id, result);
2237 fn const_evaluatable_predicates_of<'tcx>(
2240 ) -> FxIndexSet<(ty::Predicate<'tcx>, Span)> {
2241 struct ConstCollector<'tcx> {
2243 preds: FxIndexSet<(ty::Predicate<'tcx>, Span)>,
2246 impl<'tcx> intravisit::Visitor<'tcx> for ConstCollector<'tcx> {
2247 type Map = Map<'tcx>;
2249 fn nested_visit_map(&mut self) -> intravisit::NestedVisitorMap<Self::Map> {
2250 intravisit::NestedVisitorMap::None
2253 fn visit_anon_const(&mut self, c: &'tcx hir::AnonConst) {
2254 let def_id = self.tcx.hir().local_def_id(c.hir_id);
2255 let ct = ty::Const::from_anon_const(self.tcx, def_id);
2256 if let ty::ConstKind::Unevaluated(uv) = ct.val {
2257 assert_eq!(uv.promoted, None);
2258 let span = self.tcx.hir().span(c.hir_id);
2260 ty::PredicateKind::ConstEvaluatable(uv.def, uv.substs).to_predicate(self.tcx),
2267 let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
2268 let node = tcx.hir().get(hir_id);
2270 let mut collector = ConstCollector { tcx, preds: FxIndexSet::default() };
2271 if let hir::Node::Item(item) = node {
2272 if let hir::ItemKind::Impl(ref impl_) = item.kind {
2273 if let Some(of_trait) = &impl_.of_trait {
2274 debug!("const_evaluatable_predicates_of({:?}): visit impl trait_ref", def_id);
2275 collector.visit_trait_ref(of_trait);
2278 debug!("const_evaluatable_predicates_of({:?}): visit_self_ty", def_id);
2279 collector.visit_ty(impl_.self_ty);
2283 if let Some(generics) = node.generics() {
2284 debug!("const_evaluatable_predicates_of({:?}): visit_generics", def_id);
2285 collector.visit_generics(generics);
2288 if let Some(fn_sig) = tcx.hir().fn_sig_by_hir_id(hir_id) {
2289 debug!("const_evaluatable_predicates_of({:?}): visit_fn_decl", def_id);
2290 collector.visit_fn_decl(fn_sig.decl);
2292 debug!("const_evaluatable_predicates_of({:?}) = {:?}", def_id, collector.preds);
2297 fn trait_explicit_predicates_and_bounds(
2300 ) -> ty::GenericPredicates<'_> {
2301 assert_eq!(tcx.def_kind(def_id), DefKind::Trait);
2302 gather_explicit_predicates_of(tcx, def_id.to_def_id())
2305 fn explicit_predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicates<'_> {
2306 if let DefKind::Trait = tcx.def_kind(def_id) {
2307 // Remove bounds on associated types from the predicates, they will be
2308 // returned by `explicit_item_bounds`.
2309 let predicates_and_bounds = tcx.trait_explicit_predicates_and_bounds(def_id.expect_local());
2310 let trait_identity_substs = InternalSubsts::identity_for_item(tcx, def_id);
2312 let is_assoc_item_ty = |ty: Ty<'_>| {
2313 // For a predicate from a where clause to become a bound on an
2315 // * It must use the identity substs of the item.
2316 // * Since any generic parameters on the item are not in scope,
2317 // this means that the item is not a GAT, and its identity
2318 // substs are the same as the trait's.
2319 // * It must be an associated type for this trait (*not* a
2321 if let ty::Projection(projection) = ty.kind() {
2322 projection.substs == trait_identity_substs
2323 && tcx.associated_item(projection.item_def_id).container.id() == def_id
2329 let predicates: Vec<_> = predicates_and_bounds
2333 .filter(|(pred, _)| match pred.kind().skip_binder() {
2334 ty::PredicateKind::Trait(tr, _) => !is_assoc_item_ty(tr.self_ty()),
2335 ty::PredicateKind::Projection(proj) => {
2336 !is_assoc_item_ty(proj.projection_ty.self_ty())
2338 ty::PredicateKind::TypeOutlives(outlives) => !is_assoc_item_ty(outlives.0),
2342 if predicates.len() == predicates_and_bounds.predicates.len() {
2343 predicates_and_bounds
2345 ty::GenericPredicates {
2346 parent: predicates_and_bounds.parent,
2347 predicates: tcx.arena.alloc_slice(&predicates),
2351 gather_explicit_predicates_of(tcx, def_id)
2355 fn projection_ty_from_predicates(
2360 // def_id of `N` in `<T as Trait>::N`
2363 ) -> Option<ty::ProjectionTy<'tcx>> {
2364 let (ty_def_id, item_def_id) = key;
2365 let mut projection_ty = None;
2366 for (predicate, _) in tcx.predicates_of(ty_def_id).predicates {
2367 if let ty::PredicateKind::Projection(projection_predicate) = predicate.kind().skip_binder()
2369 if item_def_id == projection_predicate.projection_ty.item_def_id {
2370 projection_ty = Some(projection_predicate.projection_ty);
2378 /// Converts a specific `GenericBound` from the AST into a set of
2379 /// predicates that apply to the self type. A vector is returned
2380 /// because this can be anywhere from zero predicates (`T: ?Sized` adds no
2381 /// predicates) to one (`T: Foo`) to many (`T: Bar<X = i32>` adds `T: Bar`
2382 /// and `<T as Bar>::X == i32`).
2383 fn predicates_from_bound<'tcx>(
2384 astconv: &dyn AstConv<'tcx>,
2386 bound: &'tcx hir::GenericBound<'tcx>,
2387 constness: hir::Constness,
2388 ) -> Vec<(ty::Predicate<'tcx>, Span)> {
2390 hir::GenericBound::Trait(ref tr, modifier) => {
2391 let constness = match modifier {
2392 hir::TraitBoundModifier::Maybe => return vec![],
2393 hir::TraitBoundModifier::MaybeConst => hir::Constness::NotConst,
2394 hir::TraitBoundModifier::None => constness,
2397 let mut bounds = Bounds::default();
2398 let _ = astconv.instantiate_poly_trait_ref(
2406 bounds.predicates(astconv.tcx(), param_ty)
2408 hir::GenericBound::LangItemTrait(lang_item, span, hir_id, args) => {
2409 let mut bounds = Bounds::default();
2410 astconv.instantiate_lang_item_trait_ref(
2418 bounds.predicates(astconv.tcx(), param_ty)
2420 hir::GenericBound::Outlives(ref lifetime) => {
2421 let region = astconv.ast_region_to_region(lifetime, None);
2422 let pred = ty::PredicateKind::TypeOutlives(ty::OutlivesPredicate(param_ty, region))
2423 .to_predicate(astconv.tcx());
2424 vec![(pred, lifetime.span)]
2429 fn compute_sig_of_foreign_fn_decl<'tcx>(
2432 decl: &'tcx hir::FnDecl<'tcx>,
2435 ) -> ty::PolyFnSig<'tcx> {
2436 let unsafety = if abi == abi::Abi::RustIntrinsic {
2437 intrinsic_operation_unsafety(tcx.item_name(def_id))
2439 hir::Unsafety::Unsafe
2441 let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
2442 let fty = <dyn AstConv<'_>>::ty_of_fn(
2443 &ItemCtxt::new(tcx, def_id),
2448 &hir::Generics::empty(),
2453 // Feature gate SIMD types in FFI, since I am not sure that the
2454 // ABIs are handled at all correctly. -huonw
2455 if abi != abi::Abi::RustIntrinsic
2456 && abi != abi::Abi::PlatformIntrinsic
2457 && !tcx.features().simd_ffi
2459 let check = |ast_ty: &hir::Ty<'_>, ty: Ty<'_>| {
2464 .span_to_snippet(ast_ty.span)
2465 .map_or_else(|_| String::new(), |s| format!(" `{}`", s));
2470 "use of SIMD type{} in FFI is highly experimental and \
2471 may result in invalid code",
2475 .help("add `#![feature(simd_ffi)]` to the crate attributes to enable")
2479 for (input, ty) in iter::zip(decl.inputs, fty.inputs().skip_binder()) {
2482 if let hir::FnRetTy::Return(ref ty) = decl.output {
2483 check(&ty, fty.output().skip_binder())
2490 fn is_foreign_item(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
2491 match tcx.hir().get_if_local(def_id) {
2492 Some(Node::ForeignItem(..)) => true,
2494 _ => bug!("is_foreign_item applied to non-local def-id {:?}", def_id),
2498 fn static_mutability(tcx: TyCtxt<'_>, def_id: DefId) -> Option<hir::Mutability> {
2499 match tcx.hir().get_if_local(def_id) {
2501 Node::Item(&hir::Item { kind: hir::ItemKind::Static(_, mutbl, _), .. })
2502 | Node::ForeignItem(&hir::ForeignItem {
2503 kind: hir::ForeignItemKind::Static(_, mutbl),
2508 _ => bug!("static_mutability applied to non-local def-id {:?}", def_id),
2512 fn generator_kind(tcx: TyCtxt<'_>, def_id: DefId) -> Option<hir::GeneratorKind> {
2513 match tcx.hir().get_if_local(def_id) {
2514 Some(Node::Expr(&rustc_hir::Expr {
2515 kind: rustc_hir::ExprKind::Closure(_, _, body_id, _, _),
2517 })) => tcx.hir().body(body_id).generator_kind(),
2519 _ => bug!("generator_kind applied to non-local def-id {:?}", def_id),
2523 fn from_target_feature(
2526 attr: &ast::Attribute,
2527 supported_target_features: &FxHashMap<String, Option<Symbol>>,
2528 target_features: &mut Vec<Symbol>,
2530 let list = match attr.meta_item_list() {
2534 let bad_item = |span| {
2535 let msg = "malformed `target_feature` attribute input";
2536 let code = "enable = \"..\"".to_owned();
2538 .struct_span_err(span, &msg)
2539 .span_suggestion(span, "must be of the form", code, Applicability::HasPlaceholders)
2542 let rust_features = tcx.features();
2544 // Only `enable = ...` is accepted in the meta-item list.
2545 if !item.has_name(sym::enable) {
2546 bad_item(item.span());
2550 // Must be of the form `enable = "..."` (a string).
2551 let value = match item.value_str() {
2552 Some(value) => value,
2554 bad_item(item.span());
2559 // We allow comma separation to enable multiple features.
2560 target_features.extend(value.as_str().split(',').filter_map(|feature| {
2561 let feature_gate = match supported_target_features.get(feature) {
2565 format!("the feature named `{}` is not valid for this target", feature);
2566 let mut err = tcx.sess.struct_span_err(item.span(), &msg);
2569 format!("`{}` is not valid for this target", feature),
2571 if let Some(stripped) = feature.strip_prefix('+') {
2572 let valid = supported_target_features.contains_key(stripped);
2574 err.help("consider removing the leading `+` in the feature name");
2582 // Only allow features whose feature gates have been enabled.
2583 let allowed = match feature_gate.as_ref().copied() {
2584 Some(sym::arm_target_feature) => rust_features.arm_target_feature,
2585 Some(sym::aarch64_target_feature) => rust_features.aarch64_target_feature,
2586 Some(sym::hexagon_target_feature) => rust_features.hexagon_target_feature,
2587 Some(sym::powerpc_target_feature) => rust_features.powerpc_target_feature,
2588 Some(sym::mips_target_feature) => rust_features.mips_target_feature,
2589 Some(sym::riscv_target_feature) => rust_features.riscv_target_feature,
2590 Some(sym::avx512_target_feature) => rust_features.avx512_target_feature,
2591 Some(sym::sse4a_target_feature) => rust_features.sse4a_target_feature,
2592 Some(sym::tbm_target_feature) => rust_features.tbm_target_feature,
2593 Some(sym::wasm_target_feature) => rust_features.wasm_target_feature,
2594 Some(sym::cmpxchg16b_target_feature) => rust_features.cmpxchg16b_target_feature,
2595 Some(sym::adx_target_feature) => rust_features.adx_target_feature,
2596 Some(sym::movbe_target_feature) => rust_features.movbe_target_feature,
2597 Some(sym::rtm_target_feature) => rust_features.rtm_target_feature,
2598 Some(sym::f16c_target_feature) => rust_features.f16c_target_feature,
2599 Some(sym::ermsb_target_feature) => rust_features.ermsb_target_feature,
2600 Some(name) => bug!("unknown target feature gate {}", name),
2603 if !allowed && id.is_local() {
2605 &tcx.sess.parse_sess,
2606 feature_gate.unwrap(),
2608 &format!("the target feature `{}` is currently unstable", feature),
2612 Some(Symbol::intern(feature))
2617 fn linkage_by_name(tcx: TyCtxt<'_>, def_id: DefId, name: &str) -> Linkage {
2618 use rustc_middle::mir::mono::Linkage::*;
2620 // Use the names from src/llvm/docs/LangRef.rst here. Most types are only
2621 // applicable to variable declarations and may not really make sense for
2622 // Rust code in the first place but allow them anyway and trust that the
2623 // user knows what s/he's doing. Who knows, unanticipated use cases may pop
2624 // up in the future.
2626 // ghost, dllimport, dllexport and linkonce_odr_autohide are not supported
2627 // and don't have to be, LLVM treats them as no-ops.
2629 "appending" => Appending,
2630 "available_externally" => AvailableExternally,
2632 "extern_weak" => ExternalWeak,
2633 "external" => External,
2634 "internal" => Internal,
2635 "linkonce" => LinkOnceAny,
2636 "linkonce_odr" => LinkOnceODR,
2637 "private" => Private,
2639 "weak_odr" => WeakODR,
2641 let span = tcx.hir().span_if_local(def_id);
2642 if let Some(span) = span {
2643 tcx.sess.span_fatal(span, "invalid linkage specified")
2645 tcx.sess.fatal(&format!("invalid linkage specified: {}", name))
2651 fn codegen_fn_attrs(tcx: TyCtxt<'_>, id: DefId) -> CodegenFnAttrs {
2652 let attrs = tcx.get_attrs(id);
2654 let mut codegen_fn_attrs = CodegenFnAttrs::new();
2655 if should_inherit_track_caller(tcx, id) {
2656 codegen_fn_attrs.flags |= CodegenFnAttrFlags::TRACK_CALLER;
2659 let supported_target_features = tcx.supported_target_features(LOCAL_CRATE);
2661 let mut inline_span = None;
2662 let mut link_ordinal_span = None;
2663 let mut no_sanitize_span = None;
2664 for attr in attrs.iter() {
2665 if tcx.sess.check_name(attr, sym::cold) {
2666 codegen_fn_attrs.flags |= CodegenFnAttrFlags::COLD;
2667 } else if tcx.sess.check_name(attr, sym::rustc_allocator) {
2668 codegen_fn_attrs.flags |= CodegenFnAttrFlags::ALLOCATOR;
2669 } else if tcx.sess.check_name(attr, sym::unwind) {
2670 codegen_fn_attrs.flags |= CodegenFnAttrFlags::UNWIND;
2671 } else if tcx.sess.check_name(attr, sym::ffi_returns_twice) {
2672 if tcx.is_foreign_item(id) {
2673 codegen_fn_attrs.flags |= CodegenFnAttrFlags::FFI_RETURNS_TWICE;
2675 // `#[ffi_returns_twice]` is only allowed `extern fn`s.
2680 "`#[ffi_returns_twice]` may only be used on foreign functions"
2684 } else if tcx.sess.check_name(attr, sym::ffi_pure) {
2685 if tcx.is_foreign_item(id) {
2686 if attrs.iter().any(|a| tcx.sess.check_name(a, sym::ffi_const)) {
2687 // `#[ffi_const]` functions cannot be `#[ffi_pure]`
2692 "`#[ffi_const]` function cannot be `#[ffi_pure]`"
2696 codegen_fn_attrs.flags |= CodegenFnAttrFlags::FFI_PURE;
2699 // `#[ffi_pure]` is only allowed on foreign functions
2704 "`#[ffi_pure]` may only be used on foreign functions"
2708 } else if tcx.sess.check_name(attr, sym::ffi_const) {
2709 if tcx.is_foreign_item(id) {
2710 codegen_fn_attrs.flags |= CodegenFnAttrFlags::FFI_CONST;
2712 // `#[ffi_const]` is only allowed on foreign functions
2717 "`#[ffi_const]` may only be used on foreign functions"
2721 } else if tcx.sess.check_name(attr, sym::rustc_allocator_nounwind) {
2722 codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_ALLOCATOR_NOUNWIND;
2723 } else if tcx.sess.check_name(attr, sym::naked) {
2724 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NAKED;
2725 } else if tcx.sess.check_name(attr, sym::no_mangle) {
2726 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_MANGLE;
2727 } else if tcx.sess.check_name(attr, sym::no_coverage) {
2728 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_COVERAGE;
2729 } else if tcx.sess.check_name(attr, sym::rustc_std_internal_symbol) {
2730 codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL;
2731 } else if tcx.sess.check_name(attr, sym::used) {
2732 codegen_fn_attrs.flags |= CodegenFnAttrFlags::USED;
2733 } else if tcx.sess.check_name(attr, sym::cmse_nonsecure_entry) {
2734 if !matches!(tcx.fn_sig(id).abi(), abi::Abi::C { .. }) {
2739 "`#[cmse_nonsecure_entry]` requires C ABI"
2743 if !tcx.sess.target.llvm_target.contains("thumbv8m") {
2744 struct_span_err!(tcx.sess, attr.span, E0775, "`#[cmse_nonsecure_entry]` is only valid for targets with the TrustZone-M extension")
2747 codegen_fn_attrs.flags |= CodegenFnAttrFlags::CMSE_NONSECURE_ENTRY;
2748 } else if tcx.sess.check_name(attr, sym::thread_local) {
2749 codegen_fn_attrs.flags |= CodegenFnAttrFlags::THREAD_LOCAL;
2750 } else if tcx.sess.check_name(attr, sym::track_caller) {
2751 if tcx.is_closure(id) || tcx.fn_sig(id).abi() != abi::Abi::Rust {
2752 struct_span_err!(tcx.sess, attr.span, E0737, "`#[track_caller]` requires Rust ABI")
2755 codegen_fn_attrs.flags |= CodegenFnAttrFlags::TRACK_CALLER;
2756 } else if tcx.sess.check_name(attr, sym::export_name) {
2757 if let Some(s) = attr.value_str() {
2758 if s.as_str().contains('\0') {
2759 // `#[export_name = ...]` will be converted to a null-terminated string,
2760 // so it may not contain any null characters.
2765 "`export_name` may not contain null characters"
2769 codegen_fn_attrs.export_name = Some(s);
2771 } else if tcx.sess.check_name(attr, sym::target_feature) {
2772 if !tcx.is_closure(id) && tcx.fn_sig(id).unsafety() == hir::Unsafety::Normal {
2773 if !tcx.features().target_feature_11 {
2774 let mut err = feature_err(
2775 &tcx.sess.parse_sess,
2776 sym::target_feature_11,
2778 "`#[target_feature(..)]` can only be applied to `unsafe` functions",
2780 err.span_label(tcx.def_span(id), "not an `unsafe` function");
2782 } else if let Some(local_id) = id.as_local() {
2783 check_target_feature_trait_unsafe(tcx, local_id, attr.span);
2786 from_target_feature(
2790 &supported_target_features,
2791 &mut codegen_fn_attrs.target_features,
2793 } else if tcx.sess.check_name(attr, sym::linkage) {
2794 if let Some(val) = attr.value_str() {
2795 codegen_fn_attrs.linkage = Some(linkage_by_name(tcx, id, &val.as_str()));
2797 } else if tcx.sess.check_name(attr, sym::link_section) {
2798 if let Some(val) = attr.value_str() {
2799 if val.as_str().bytes().any(|b| b == 0) {
2801 "illegal null byte in link_section \
2805 tcx.sess.span_err(attr.span, &msg);
2807 codegen_fn_attrs.link_section = Some(val);
2810 } else if tcx.sess.check_name(attr, sym::link_name) {
2811 codegen_fn_attrs.link_name = attr.value_str();
2812 } else if tcx.sess.check_name(attr, sym::link_ordinal) {
2813 link_ordinal_span = Some(attr.span);
2814 if let ordinal @ Some(_) = check_link_ordinal(tcx, attr) {
2815 codegen_fn_attrs.link_ordinal = ordinal;
2817 } else if tcx.sess.check_name(attr, sym::no_sanitize) {
2818 no_sanitize_span = Some(attr.span);
2819 if let Some(list) = attr.meta_item_list() {
2820 for item in list.iter() {
2821 if item.has_name(sym::address) {
2822 codegen_fn_attrs.no_sanitize |= SanitizerSet::ADDRESS;
2823 } else if item.has_name(sym::memory) {
2824 codegen_fn_attrs.no_sanitize |= SanitizerSet::MEMORY;
2825 } else if item.has_name(sym::thread) {
2826 codegen_fn_attrs.no_sanitize |= SanitizerSet::THREAD;
2827 } else if item.has_name(sym::hwaddress) {
2828 codegen_fn_attrs.no_sanitize |= SanitizerSet::HWADDRESS;
2831 .struct_span_err(item.span(), "invalid argument for `no_sanitize`")
2832 .note("expected one of: `address`, `hwaddress`, `memory` or `thread`")
2837 } else if tcx.sess.check_name(attr, sym::instruction_set) {
2838 codegen_fn_attrs.instruction_set = match attr.meta().map(|i| i.kind) {
2839 Some(MetaItemKind::List(ref items)) => match items.as_slice() {
2840 [NestedMetaItem::MetaItem(set)] => {
2842 set.path.segments.iter().map(|x| x.ident.name).collect::<Vec<_>>();
2843 match segments.as_slice() {
2844 [sym::arm, sym::a32] | [sym::arm, sym::t32] => {
2845 if !tcx.sess.target.has_thumb_interworking {
2847 tcx.sess.diagnostic(),
2850 "target does not support `#[instruction_set]`"
2854 } else if segments[1] == sym::a32 {
2855 Some(InstructionSetAttr::ArmA32)
2856 } else if segments[1] == sym::t32 {
2857 Some(InstructionSetAttr::ArmT32)
2864 tcx.sess.diagnostic(),
2867 "invalid instruction set specified",
2876 tcx.sess.diagnostic(),
2879 "`#[instruction_set]` requires an argument"
2886 tcx.sess.diagnostic(),
2889 "cannot specify more than one instruction set"
2897 tcx.sess.diagnostic(),
2900 "must specify an instruction set"
2906 } else if tcx.sess.check_name(attr, sym::repr) {
2907 codegen_fn_attrs.alignment = match attr.meta_item_list() {
2908 Some(items) => match items.as_slice() {
2909 [item] => match item.name_value_literal() {
2910 Some((sym::align, literal)) => {
2911 let alignment = rustc_attr::parse_alignment(&literal.kind);
2914 Ok(align) => Some(align),
2917 tcx.sess.diagnostic(),
2920 "invalid `repr(align)` attribute: {}",
2939 codegen_fn_attrs.inline = attrs.iter().fold(InlineAttr::None, |ia, attr| {
2940 if !attr.has_name(sym::inline) {
2943 match attr.meta().map(|i| i.kind) {
2944 Some(MetaItemKind::Word) => {
2945 tcx.sess.mark_attr_used(attr);
2948 Some(MetaItemKind::List(ref items)) => {
2949 tcx.sess.mark_attr_used(attr);
2950 inline_span = Some(attr.span);
2951 if items.len() != 1 {
2953 tcx.sess.diagnostic(),
2956 "expected one argument"
2960 } else if list_contains_name(&items[..], sym::always) {
2962 } else if list_contains_name(&items[..], sym::never) {
2966 tcx.sess.diagnostic(),
2976 Some(MetaItemKind::NameValue(_)) => ia,
2981 codegen_fn_attrs.optimize = attrs.iter().fold(OptimizeAttr::None, |ia, attr| {
2982 if !attr.has_name(sym::optimize) {
2985 let err = |sp, s| struct_span_err!(tcx.sess.diagnostic(), sp, E0722, "{}", s).emit();
2986 match attr.meta().map(|i| i.kind) {
2987 Some(MetaItemKind::Word) => {
2988 err(attr.span, "expected one argument");
2991 Some(MetaItemKind::List(ref items)) => {
2992 tcx.sess.mark_attr_used(attr);
2993 inline_span = Some(attr.span);
2994 if items.len() != 1 {
2995 err(attr.span, "expected one argument");
2997 } else if list_contains_name(&items[..], sym::size) {
2999 } else if list_contains_name(&items[..], sym::speed) {
3002 err(items[0].span(), "invalid argument");
3006 Some(MetaItemKind::NameValue(_)) => ia,
3011 // #73631: closures inherit `#[target_feature]` annotations
3012 if tcx.features().target_feature_11 && tcx.is_closure(id) {
3013 let owner_id = tcx.parent(id).expect("closure should have a parent");
3016 .extend(tcx.codegen_fn_attrs(owner_id).target_features.iter().copied())
3019 // If a function uses #[target_feature] it can't be inlined into general
3020 // purpose functions as they wouldn't have the right target features
3021 // enabled. For that reason we also forbid #[inline(always)] as it can't be
3023 if !codegen_fn_attrs.target_features.is_empty() {
3024 if codegen_fn_attrs.inline == InlineAttr::Always {
3025 if let Some(span) = inline_span {
3028 "cannot use `#[inline(always)]` with \
3029 `#[target_feature]`",
3035 if !codegen_fn_attrs.no_sanitize.is_empty() {
3036 if codegen_fn_attrs.inline == InlineAttr::Always {
3037 if let (Some(no_sanitize_span), Some(inline_span)) = (no_sanitize_span, inline_span) {
3038 let hir_id = tcx.hir().local_def_id_to_hir_id(id.expect_local());
3039 tcx.struct_span_lint_hir(
3040 lint::builtin::INLINE_NO_SANITIZE,
3044 lint.build("`no_sanitize` will have no effect after inlining")
3045 .span_note(inline_span, "inlining requested here")
3053 // Weak lang items have the same semantics as "std internal" symbols in the
3054 // sense that they're preserved through all our LTO passes and only
3055 // strippable by the linker.
3057 // Additionally weak lang items have predetermined symbol names.
3058 if tcx.is_weak_lang_item(id) {
3059 codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL;
3061 let check_name = |attr, sym| tcx.sess.check_name(attr, sym);
3062 if let Some(name) = weak_lang_items::link_name(check_name, &attrs) {
3063 codegen_fn_attrs.export_name = Some(name);
3064 codegen_fn_attrs.link_name = Some(name);
3066 check_link_name_xor_ordinal(tcx, &codegen_fn_attrs, link_ordinal_span);
3068 // Internal symbols to the standard library all have no_mangle semantics in
3069 // that they have defined symbol names present in the function name. This
3070 // also applies to weak symbols where they all have known symbol names.
3071 if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL) {
3072 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_MANGLE;
3078 /// Checks if the provided DefId is a method in a trait impl for a trait which has track_caller
3079 /// applied to the method prototype.
3080 fn should_inherit_track_caller(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
3081 if let Some(impl_item) = tcx.opt_associated_item(def_id) {
3082 if let ty::AssocItemContainer::ImplContainer(impl_def_id) = impl_item.container {
3083 if let Some(trait_def_id) = tcx.trait_id_of_impl(impl_def_id) {
3084 if let Some(trait_item) = tcx
3085 .associated_items(trait_def_id)
3086 .filter_by_name_unhygienic(impl_item.ident.name)
3087 .find(move |trait_item| {
3088 trait_item.kind == ty::AssocKind::Fn
3089 && tcx.hygienic_eq(impl_item.ident, trait_item.ident, trait_def_id)
3093 .codegen_fn_attrs(trait_item.def_id)
3095 .intersects(CodegenFnAttrFlags::TRACK_CALLER);
3104 fn check_link_ordinal(tcx: TyCtxt<'_>, attr: &ast::Attribute) -> Option<usize> {
3105 use rustc_ast::{Lit, LitIntType, LitKind};
3106 let meta_item_list = attr.meta_item_list();
3107 let meta_item_list: Option<&[ast::NestedMetaItem]> = meta_item_list.as_ref().map(Vec::as_ref);
3108 let sole_meta_list = match meta_item_list {
3109 Some([item]) => item.literal(),
3112 if let Some(Lit { kind: LitKind::Int(ordinal, LitIntType::Unsuffixed), .. }) = sole_meta_list {
3113 if *ordinal <= usize::MAX as u128 {
3114 Some(*ordinal as usize)
3116 let msg = format!("ordinal value in `link_ordinal` is too large: `{}`", &ordinal);
3118 .struct_span_err(attr.span, &msg)
3119 .note("the value may not exceed `usize::MAX`")
3125 .struct_span_err(attr.span, "illegal ordinal format in `link_ordinal`")
3126 .note("an unsuffixed integer value, e.g., `1`, is expected")
3132 fn check_link_name_xor_ordinal(
3134 codegen_fn_attrs: &CodegenFnAttrs,
3135 inline_span: Option<Span>,
3137 if codegen_fn_attrs.link_name.is_none() || codegen_fn_attrs.link_ordinal.is_none() {
3140 let msg = "cannot use `#[link_name]` with `#[link_ordinal]`";
3141 if let Some(span) = inline_span {
3142 tcx.sess.span_err(span, msg);
3148 /// Checks the function annotated with `#[target_feature]` is not a safe
3149 /// trait method implementation, reporting an error if it is.
3150 fn check_target_feature_trait_unsafe(tcx: TyCtxt<'_>, id: LocalDefId, attr_span: Span) {
3151 let hir_id = tcx.hir().local_def_id_to_hir_id(id);
3152 let node = tcx.hir().get(hir_id);
3153 if let Node::ImplItem(hir::ImplItem { kind: hir::ImplItemKind::Fn(..), .. }) = node {
3154 let parent_id = tcx.hir().get_parent_item(hir_id);
3155 let parent_item = tcx.hir().expect_item(parent_id);
3156 if let hir::ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }) = parent_item.kind {
3160 "`#[target_feature(..)]` cannot be applied to safe trait method",
3162 .span_label(attr_span, "cannot be applied to safe trait method")
3163 .span_label(tcx.def_span(id), "not an `unsafe` function")