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::Map;
39 use rustc_middle::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs};
40 use rustc_middle::mir::mono::Linkage;
41 use rustc_middle::ty::query::Providers;
42 use rustc_middle::ty::subst::InternalSubsts;
43 use rustc_middle::ty::util::Discr;
44 use rustc_middle::ty::util::IntTypeExt;
45 use rustc_middle::ty::{self, AdtKind, Const, DefIdTree, ToPolyTraitRef, Ty, TyCtxt};
46 use rustc_middle::ty::{ReprOptions, ToPredicate, WithConstness};
47 use rustc_session::lint;
48 use rustc_session::parse::feature_err;
49 use rustc_span::symbol::{kw, sym, Ident, Symbol};
50 use rustc_span::{Span, DUMMY_SP};
51 use rustc_target::spec::{abi, SanitizerSet};
52 use rustc_trait_selection::traits::error_reporting::suggestions::NextTypeParamName;
58 struct OnlySelfBounds(bool);
60 ///////////////////////////////////////////////////////////////////////////
63 fn collect_mod_item_types(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
64 tcx.hir().visit_item_likes_in_module(
66 &mut CollectItemTypesVisitor { tcx }.as_deep_visitor(),
70 pub fn provide(providers: &mut Providers) {
71 *providers = Providers {
72 opt_const_param_of: type_of::opt_const_param_of,
73 type_of: type_of::type_of,
74 item_bounds: item_bounds::item_bounds,
75 explicit_item_bounds: item_bounds::explicit_item_bounds,
78 predicates_defined_on,
79 explicit_predicates_of,
81 super_predicates_that_define_assoc_type,
82 trait_explicit_predicates_and_bounds,
83 type_param_predicates,
93 collect_mod_item_types,
94 should_inherit_track_caller,
99 ///////////////////////////////////////////////////////////////////////////
101 /// Context specific to some particular item. This is what implements
102 /// `AstConv`. It has information about the predicates that are defined
103 /// on the trait. Unfortunately, this predicate information is
104 /// available in various different forms at various points in the
105 /// process. So we can't just store a pointer to e.g., the AST or the
106 /// parsed ty form, we have to be more flexible. To this end, the
107 /// `ItemCtxt` is parameterized by a `DefId` that it uses to satisfy
108 /// `get_type_parameter_bounds` requests, drawing the information from
109 /// the AST (`hir::Generics`), recursively.
110 pub struct ItemCtxt<'tcx> {
115 ///////////////////////////////////////////////////////////////////////////
118 crate struct PlaceholderHirTyCollector(crate Vec<Span>);
120 impl<'v> Visitor<'v> for PlaceholderHirTyCollector {
121 type Map = intravisit::ErasedMap<'v>;
123 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
124 NestedVisitorMap::None
126 fn visit_ty(&mut self, t: &'v hir::Ty<'v>) {
127 if let hir::TyKind::Infer = t.kind {
130 intravisit::walk_ty(self, t)
134 struct CollectItemTypesVisitor<'tcx> {
138 /// If there are any placeholder types (`_`), emit an error explaining that this is not allowed
139 /// and suggest adding type parameters in the appropriate place, taking into consideration any and
140 /// all already existing generic type parameters to avoid suggesting a name that is already in use.
141 crate fn placeholder_type_error(
144 generics: &[hir::GenericParam<'_>],
145 placeholder_types: Vec<Span>,
147 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, kind);
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_or_static = false;
185 if let Some(hir_ty) = hir_ty {
186 if let hir::TyKind::BareFn(_) = hir_ty.kind {
189 // Check if parent is const or static
190 let parent_id = tcx.hir().get_parent_node(hir_ty.hir_id);
191 let parent_node = tcx.hir().get(parent_id);
193 is_const_or_static = match parent_node {
194 Node::Item(&hir::Item {
195 kind: hir::ItemKind::Const(..) | hir::ItemKind::Static(..),
198 | Node::TraitItem(&hir::TraitItem {
199 kind: hir::TraitItemKind::Const(..),
202 | Node::ImplItem(&hir::ImplItem {
203 kind: hir::ImplItemKind::Const(..), ..
210 // if function is wrapped around a const or static,
211 // then don't show the suggestion
212 if !(is_fn && is_const_or_static) {
213 err.multipart_suggestion(
214 "use type parameters instead",
216 Applicability::HasPlaceholders,
223 fn reject_placeholder_type_signatures_in_item(tcx: TyCtxt<'tcx>, item: &'tcx hir::Item<'tcx>) {
224 let (generics, suggest) = match &item.kind {
225 hir::ItemKind::Union(_, generics)
226 | hir::ItemKind::Enum(_, generics)
227 | hir::ItemKind::TraitAlias(generics, _)
228 | hir::ItemKind::Trait(_, _, generics, ..)
229 | hir::ItemKind::Impl(hir::Impl { generics, .. })
230 | hir::ItemKind::Struct(_, generics) => (generics, true),
231 hir::ItemKind::OpaqueTy(hir::OpaqueTy { generics, .. })
232 | hir::ItemKind::TyAlias(_, generics) => (generics, false),
233 // `static`, `fn` and `const` are handled elsewhere to suggest appropriate type.
237 let mut visitor = PlaceholderHirTyCollector::default();
238 visitor.visit_item(item);
240 placeholder_type_error(
251 impl Visitor<'tcx> for CollectItemTypesVisitor<'tcx> {
252 type Map = Map<'tcx>;
254 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
255 NestedVisitorMap::OnlyBodies(self.tcx.hir())
258 fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) {
259 convert_item(self.tcx, item.item_id());
260 reject_placeholder_type_signatures_in_item(self.tcx, item);
261 intravisit::walk_item(self, item);
264 fn visit_generics(&mut self, generics: &'tcx hir::Generics<'tcx>) {
265 for param in generics.params {
267 hir::GenericParamKind::Lifetime { .. } => {}
268 hir::GenericParamKind::Type { default: Some(_), .. } => {
269 let def_id = self.tcx.hir().local_def_id(param.hir_id);
270 self.tcx.ensure().type_of(def_id);
272 hir::GenericParamKind::Type { .. } => {}
273 hir::GenericParamKind::Const { default, .. } => {
274 let def_id = self.tcx.hir().local_def_id(param.hir_id);
275 self.tcx.ensure().type_of(def_id);
276 if let Some(default) = default {
277 let default_def_id = self.tcx.hir().local_def_id(default.hir_id);
278 // need to store default and type of default
279 self.tcx.ensure().type_of(default_def_id);
280 self.tcx.ensure().const_param_default(def_id);
285 intravisit::walk_generics(self, generics);
288 fn visit_expr(&mut self, expr: &'tcx hir::Expr<'tcx>) {
289 if let hir::ExprKind::Closure(..) = expr.kind {
290 let def_id = self.tcx.hir().local_def_id(expr.hir_id);
291 self.tcx.ensure().generics_of(def_id);
292 self.tcx.ensure().type_of(def_id);
294 intravisit::walk_expr(self, expr);
297 fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem<'tcx>) {
298 convert_trait_item(self.tcx, trait_item.trait_item_id());
299 intravisit::walk_trait_item(self, trait_item);
302 fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem<'tcx>) {
303 convert_impl_item(self.tcx, impl_item.impl_item_id());
304 intravisit::walk_impl_item(self, impl_item);
308 ///////////////////////////////////////////////////////////////////////////
309 // Utility types and common code for the above passes.
311 fn bad_placeholder_type(
313 mut spans: Vec<Span>,
315 ) -> rustc_errors::DiagnosticBuilder<'tcx> {
316 let kind = if kind.ends_with('s') { format!("{}es", kind) } else { format!("{}s", kind) };
319 let mut err = struct_span_err!(
323 "the type placeholder `_` is not allowed within types on item signatures for {}",
327 err.span_label(span, "not allowed in type signatures");
332 impl ItemCtxt<'tcx> {
333 pub fn new(tcx: TyCtxt<'tcx>, item_def_id: DefId) -> ItemCtxt<'tcx> {
334 ItemCtxt { tcx, item_def_id }
337 pub fn to_ty(&self, ast_ty: &hir::Ty<'_>) -> Ty<'tcx> {
338 <dyn AstConv<'_>>::ast_ty_to_ty(self, ast_ty)
341 pub fn hir_id(&self) -> hir::HirId {
342 self.tcx.hir().local_def_id_to_hir_id(self.item_def_id.expect_local())
345 pub fn node(&self) -> hir::Node<'tcx> {
346 self.tcx.hir().get(self.hir_id())
350 impl AstConv<'tcx> for ItemCtxt<'tcx> {
351 fn tcx(&self) -> TyCtxt<'tcx> {
355 fn item_def_id(&self) -> Option<DefId> {
356 Some(self.item_def_id)
359 fn default_constness_for_trait_bounds(&self) -> hir::Constness {
360 self.node().constness()
363 fn get_type_parameter_bounds(
368 ) -> ty::GenericPredicates<'tcx> {
369 self.tcx.at(span).type_param_predicates((
371 def_id.expect_local(),
376 fn re_infer(&self, _: Option<&ty::GenericParamDef>, _: Span) -> Option<ty::Region<'tcx>> {
380 fn allow_ty_infer(&self) -> bool {
384 fn ty_infer(&self, _: Option<&ty::GenericParamDef>, span: Span) -> Ty<'tcx> {
385 self.tcx().ty_error_with_message(span, "bad_placeholder_type")
391 _: Option<&ty::GenericParamDef>,
393 ) -> &'tcx Const<'tcx> {
394 bad_placeholder_type(self.tcx(), vec![span], "generic").emit();
395 // Typeck doesn't expect erased regions to be returned from `type_of`.
396 let ty = self.tcx.fold_regions(ty, &mut false, |r, _| match r {
397 ty::ReErased => self.tcx.lifetimes.re_static,
400 self.tcx().const_error(ty)
403 fn projected_ty_from_poly_trait_ref(
407 item_segment: &hir::PathSegment<'_>,
408 poly_trait_ref: ty::PolyTraitRef<'tcx>,
410 if let Some(trait_ref) = poly_trait_ref.no_bound_vars() {
411 let item_substs = <dyn AstConv<'tcx>>::create_substs_for_associated_item(
419 self.tcx().mk_projection(item_def_id, item_substs)
421 // There are no late-bound regions; we can just ignore the binder.
422 let mut err = struct_span_err!(
426 "cannot use the associated type of a trait \
427 with uninferred generic parameters"
431 hir::Node::Field(_) | hir::Node::Ctor(_) | hir::Node::Variant(_) => {
433 self.tcx.hir().expect_item(self.tcx.hir().get_parent_item(self.hir_id()));
435 hir::ItemKind::Enum(_, generics)
436 | hir::ItemKind::Struct(_, generics)
437 | hir::ItemKind::Union(_, generics) => {
438 let lt_name = get_new_lifetime_name(self.tcx, poly_trait_ref, generics);
439 let (lt_sp, sugg) = match generics.params {
440 [] => (generics.span, format!("<{}>", lt_name)),
442 (bound.span.shrink_to_lo(), format!("{}, ", lt_name))
445 let suggestions = vec![
451 // Replace the existing lifetimes with a new named lifetime.
453 .replace_late_bound_regions(poly_trait_ref, |_| {
454 self.tcx.mk_region(ty::ReEarlyBound(
455 ty::EarlyBoundRegion {
458 name: Symbol::intern(<_name),
467 err.multipart_suggestion(
468 "use a fully qualified path with explicit lifetimes",
470 Applicability::MaybeIncorrect,
476 hir::Node::Item(hir::Item {
478 hir::ItemKind::Struct(..) | hir::ItemKind::Enum(..) | hir::ItemKind::Union(..),
482 | hir::Node::ForeignItem(_)
483 | hir::Node::TraitItem(_)
484 | hir::Node::ImplItem(_) => {
487 "use a fully qualified path with inferred lifetimes",
490 // Erase named lt, we want `<A as B<'_>::C`, not `<A as B<'a>::C`.
491 self.tcx.anonymize_late_bound_regions(poly_trait_ref).skip_binder(),
494 Applicability::MaybeIncorrect,
500 self.tcx().ty_error()
504 fn normalize_ty(&self, _span: Span, ty: Ty<'tcx>) -> Ty<'tcx> {
505 // Types in item signatures are not normalized to avoid undue dependencies.
509 fn set_tainted_by_errors(&self) {
510 // There's no obvious place to track this, so just let it go.
513 fn record_ty(&self, _hir_id: hir::HirId, _ty: Ty<'tcx>, _span: Span) {
514 // There's no place to record types from signatures?
518 /// Synthesize a new lifetime name that doesn't clash with any of the lifetimes already present.
519 fn get_new_lifetime_name<'tcx>(
521 poly_trait_ref: ty::PolyTraitRef<'tcx>,
522 generics: &hir::Generics<'tcx>,
524 let existing_lifetimes = tcx
525 .collect_referenced_late_bound_regions(&poly_trait_ref)
528 if let ty::BoundRegionKind::BrNamed(_, name) = lt {
529 Some(name.as_str().to_string())
534 .chain(generics.params.iter().filter_map(|param| {
535 if let hir::GenericParamKind::Lifetime { .. } = ¶m.kind {
536 Some(param.name.ident().as_str().to_string())
541 .collect::<FxHashSet<String>>();
543 let a_to_z_repeat_n = |n| {
544 (b'a'..=b'z').map(move |c| {
545 let mut s = '\''.to_string();
546 s.extend(std::iter::repeat(char::from(c)).take(n));
551 // If all single char lifetime names are present, we wrap around and double the chars.
552 (1..).flat_map(a_to_z_repeat_n).find(|lt| !existing_lifetimes.contains(lt.as_str())).unwrap()
555 /// Returns the predicates defined on `item_def_id` of the form
556 /// `X: Foo` where `X` is the type parameter `def_id`.
557 fn type_param_predicates(
559 (item_def_id, def_id, assoc_name): (DefId, LocalDefId, Ident),
560 ) -> ty::GenericPredicates<'_> {
563 // In the AST, bounds can derive from two places. Either
564 // written inline like `<T: Foo>` or in a where-clause like
567 let param_id = tcx.hir().local_def_id_to_hir_id(def_id);
568 let param_owner = tcx.hir().ty_param_owner(param_id);
569 let param_owner_def_id = tcx.hir().local_def_id(param_owner);
570 let generics = tcx.generics_of(param_owner_def_id);
571 let index = generics.param_def_id_to_index[&def_id.to_def_id()];
572 let ty = tcx.mk_ty_param(index, tcx.hir().ty_param_name(param_id));
574 // Don't look for bounds where the type parameter isn't in scope.
575 let parent = if item_def_id == param_owner_def_id.to_def_id() {
578 tcx.generics_of(item_def_id).parent
581 let mut result = parent
583 let icx = ItemCtxt::new(tcx, parent);
584 icx.get_type_parameter_bounds(DUMMY_SP, def_id.to_def_id(), assoc_name)
586 .unwrap_or_default();
587 let mut extend = None;
589 let item_hir_id = tcx.hir().local_def_id_to_hir_id(item_def_id.expect_local());
590 let ast_generics = match tcx.hir().get(item_hir_id) {
591 Node::TraitItem(item) => &item.generics,
593 Node::ImplItem(item) => &item.generics,
595 Node::Item(item) => {
597 ItemKind::Fn(.., ref generics, _)
598 | ItemKind::Impl(hir::Impl { ref generics, .. })
599 | ItemKind::TyAlias(_, ref generics)
600 | ItemKind::OpaqueTy(OpaqueTy { ref generics, impl_trait_fn: None, .. })
601 | ItemKind::Enum(_, ref generics)
602 | ItemKind::Struct(_, ref generics)
603 | ItemKind::Union(_, ref generics) => generics,
604 ItemKind::Trait(_, _, ref generics, ..) => {
605 // Implied `Self: Trait` and supertrait bounds.
606 if param_id == item_hir_id {
607 let identity_trait_ref = ty::TraitRef::identity(tcx, item_def_id);
609 Some((identity_trait_ref.without_const().to_predicate(tcx), item.span));
617 Node::ForeignItem(item) => match item.kind {
618 ForeignItemKind::Fn(_, _, ref generics) => generics,
625 let icx = ItemCtxt::new(tcx, item_def_id);
626 let extra_predicates = extend.into_iter().chain(
627 icx.type_parameter_bounds_in_generics(
631 OnlySelfBounds(true),
635 .filter(|(predicate, _)| match predicate.kind().skip_binder() {
636 ty::PredicateKind::Trait(data, _) => data.self_ty().is_param(index),
641 tcx.arena.alloc_from_iter(result.predicates.iter().copied().chain(extra_predicates));
645 impl ItemCtxt<'tcx> {
646 /// Finds bounds from `hir::Generics`. This requires scanning through the
647 /// AST. We do this to avoid having to convert *all* the bounds, which
648 /// would create artificial cycles. Instead, we can only convert the
649 /// bounds for a type parameter `X` if `X::Foo` is used.
650 fn type_parameter_bounds_in_generics(
652 ast_generics: &'tcx hir::Generics<'tcx>,
653 param_id: hir::HirId,
655 only_self_bounds: OnlySelfBounds,
656 assoc_name: Option<Ident>,
657 ) -> Vec<(ty::Predicate<'tcx>, Span)> {
658 let constness = self.default_constness_for_trait_bounds();
659 let from_ty_params = ast_generics
662 .filter_map(|param| match param.kind {
663 GenericParamKind::Type { .. } if param.hir_id == param_id => Some(¶m.bounds),
666 .flat_map(|bounds| bounds.iter())
667 .filter(|b| match assoc_name {
668 Some(assoc_name) => self.bound_defines_assoc_item(b, assoc_name),
671 .flat_map(|b| predicates_from_bound(self, ty, b, constness));
673 let from_where_clauses = ast_generics
677 .filter_map(|wp| match *wp {
678 hir::WherePredicate::BoundPredicate(ref bp) => Some(bp),
682 let bt = if is_param(self.tcx, &bp.bounded_ty, param_id) {
684 } else if !only_self_bounds.0 {
685 Some(self.to_ty(&bp.bounded_ty))
691 .filter(|b| match assoc_name {
692 Some(assoc_name) => self.bound_defines_assoc_item(b, assoc_name),
695 .filter_map(move |b| bt.map(|bt| (bt, b)))
697 .flat_map(|(bt, b)| predicates_from_bound(self, bt, b, constness));
699 from_ty_params.chain(from_where_clauses).collect()
702 fn bound_defines_assoc_item(&self, b: &hir::GenericBound<'_>, assoc_name: Ident) -> bool {
703 debug!("bound_defines_assoc_item(b={:?}, assoc_name={:?})", b, assoc_name);
706 hir::GenericBound::Trait(poly_trait_ref, _) => {
707 let trait_ref = &poly_trait_ref.trait_ref;
708 if let Some(trait_did) = trait_ref.trait_def_id() {
709 self.tcx.trait_may_define_assoc_type(trait_did, assoc_name)
719 /// Tests whether this is the AST for a reference to the type
720 /// parameter with ID `param_id`. We use this so as to avoid running
721 /// `ast_ty_to_ty`, because we want to avoid triggering an all-out
722 /// conversion of the type to avoid inducing unnecessary cycles.
723 fn is_param(tcx: TyCtxt<'_>, ast_ty: &hir::Ty<'_>, param_id: hir::HirId) -> bool {
724 if let hir::TyKind::Path(hir::QPath::Resolved(None, ref path)) = ast_ty.kind {
726 Res::SelfTy(Some(def_id), None) | Res::Def(DefKind::TyParam, def_id) => {
727 def_id == tcx.hir().local_def_id(param_id).to_def_id()
736 fn convert_item(tcx: TyCtxt<'_>, item_id: hir::ItemId) {
737 let it = tcx.hir().item(item_id);
738 debug!("convert: item {} with id {}", it.ident, it.hir_id());
739 let def_id = item_id.def_id;
742 // These don't define types.
743 hir::ItemKind::ExternCrate(_)
744 | hir::ItemKind::Use(..)
745 | hir::ItemKind::Mod(_)
746 | hir::ItemKind::GlobalAsm(_) => {}
747 hir::ItemKind::ForeignMod { items, .. } => {
749 let item = tcx.hir().foreign_item(item.id);
750 tcx.ensure().generics_of(item.def_id);
751 tcx.ensure().type_of(item.def_id);
752 tcx.ensure().predicates_of(item.def_id);
754 hir::ForeignItemKind::Fn(..) => tcx.ensure().fn_sig(item.def_id),
755 hir::ForeignItemKind::Static(..) => {
756 let mut visitor = PlaceholderHirTyCollector::default();
757 visitor.visit_foreign_item(item);
758 placeholder_type_error(
772 hir::ItemKind::Enum(ref enum_definition, _) => {
773 tcx.ensure().generics_of(def_id);
774 tcx.ensure().type_of(def_id);
775 tcx.ensure().predicates_of(def_id);
776 convert_enum_variant_types(tcx, def_id.to_def_id(), &enum_definition.variants);
778 hir::ItemKind::Impl { .. } => {
779 tcx.ensure().generics_of(def_id);
780 tcx.ensure().type_of(def_id);
781 tcx.ensure().impl_trait_ref(def_id);
782 tcx.ensure().predicates_of(def_id);
784 hir::ItemKind::Trait(..) => {
785 tcx.ensure().generics_of(def_id);
786 tcx.ensure().trait_def(def_id);
787 tcx.at(it.span).super_predicates_of(def_id);
788 tcx.ensure().predicates_of(def_id);
790 hir::ItemKind::TraitAlias(..) => {
791 tcx.ensure().generics_of(def_id);
792 tcx.at(it.span).super_predicates_of(def_id);
793 tcx.ensure().predicates_of(def_id);
795 hir::ItemKind::Struct(ref struct_def, _) | hir::ItemKind::Union(ref struct_def, _) => {
796 tcx.ensure().generics_of(def_id);
797 tcx.ensure().type_of(def_id);
798 tcx.ensure().predicates_of(def_id);
800 for f in struct_def.fields() {
801 let def_id = tcx.hir().local_def_id(f.hir_id);
802 tcx.ensure().generics_of(def_id);
803 tcx.ensure().type_of(def_id);
804 tcx.ensure().predicates_of(def_id);
807 if let Some(ctor_hir_id) = struct_def.ctor_hir_id() {
808 convert_variant_ctor(tcx, ctor_hir_id);
812 // Desugared from `impl Trait`, so visited by the function's return type.
813 hir::ItemKind::OpaqueTy(hir::OpaqueTy { impl_trait_fn: Some(_), .. }) => {}
815 // Don't call `type_of` on opaque types, since that depends on type
816 // checking function bodies. `check_item_type` ensures that it's called
818 hir::ItemKind::OpaqueTy(..) => {
819 tcx.ensure().generics_of(def_id);
820 tcx.ensure().predicates_of(def_id);
821 tcx.ensure().explicit_item_bounds(def_id);
823 hir::ItemKind::TyAlias(..)
824 | hir::ItemKind::Static(..)
825 | hir::ItemKind::Const(..)
826 | hir::ItemKind::Fn(..) => {
827 tcx.ensure().generics_of(def_id);
828 tcx.ensure().type_of(def_id);
829 tcx.ensure().predicates_of(def_id);
831 hir::ItemKind::Fn(..) => tcx.ensure().fn_sig(def_id),
832 hir::ItemKind::OpaqueTy(..) => tcx.ensure().item_bounds(def_id),
833 hir::ItemKind::Const(ty, ..) | hir::ItemKind::Static(ty, ..) => {
834 // (#75889): Account for `const C: dyn Fn() -> _ = "";`
835 if let hir::TyKind::TraitObject(..) = ty.kind {
836 let mut visitor = PlaceholderHirTyCollector::default();
837 visitor.visit_item(it);
838 placeholder_type_error(
855 fn convert_trait_item(tcx: TyCtxt<'_>, trait_item_id: hir::TraitItemId) {
856 let trait_item = tcx.hir().trait_item(trait_item_id);
857 tcx.ensure().generics_of(trait_item_id.def_id);
859 match trait_item.kind {
860 hir::TraitItemKind::Fn(..) => {
861 tcx.ensure().type_of(trait_item_id.def_id);
862 tcx.ensure().fn_sig(trait_item_id.def_id);
865 hir::TraitItemKind::Const(.., Some(_)) => {
866 tcx.ensure().type_of(trait_item_id.def_id);
869 hir::TraitItemKind::Const(..) => {
870 tcx.ensure().type_of(trait_item_id.def_id);
871 // Account for `const C: _;`.
872 let mut visitor = PlaceholderHirTyCollector::default();
873 visitor.visit_trait_item(trait_item);
874 placeholder_type_error(tcx, None, &[], visitor.0, false, None, "constant");
877 hir::TraitItemKind::Type(_, Some(_)) => {
878 tcx.ensure().item_bounds(trait_item_id.def_id);
879 tcx.ensure().type_of(trait_item_id.def_id);
880 // Account for `type T = _;`.
881 let mut visitor = PlaceholderHirTyCollector::default();
882 visitor.visit_trait_item(trait_item);
883 placeholder_type_error(tcx, None, &[], visitor.0, false, None, "associated type");
886 hir::TraitItemKind::Type(_, None) => {
887 tcx.ensure().item_bounds(trait_item_id.def_id);
888 // #74612: Visit and try to find bad placeholders
889 // even if there is no concrete type.
890 let mut visitor = PlaceholderHirTyCollector::default();
891 visitor.visit_trait_item(trait_item);
893 placeholder_type_error(tcx, None, &[], visitor.0, false, None, "associated type");
897 tcx.ensure().predicates_of(trait_item_id.def_id);
900 fn convert_impl_item(tcx: TyCtxt<'_>, impl_item_id: hir::ImplItemId) {
901 let def_id = impl_item_id.def_id;
902 tcx.ensure().generics_of(def_id);
903 tcx.ensure().type_of(def_id);
904 tcx.ensure().predicates_of(def_id);
905 let impl_item = tcx.hir().impl_item(impl_item_id);
906 match impl_item.kind {
907 hir::ImplItemKind::Fn(..) => {
908 tcx.ensure().fn_sig(def_id);
910 hir::ImplItemKind::TyAlias(_) => {
911 // Account for `type T = _;`
912 let mut visitor = PlaceholderHirTyCollector::default();
913 visitor.visit_impl_item(impl_item);
915 placeholder_type_error(tcx, None, &[], visitor.0, false, None, "associated type");
917 hir::ImplItemKind::Const(..) => {}
921 fn convert_variant_ctor(tcx: TyCtxt<'_>, ctor_id: hir::HirId) {
922 let def_id = tcx.hir().local_def_id(ctor_id);
923 tcx.ensure().generics_of(def_id);
924 tcx.ensure().type_of(def_id);
925 tcx.ensure().predicates_of(def_id);
928 fn convert_enum_variant_types(tcx: TyCtxt<'_>, def_id: DefId, variants: &[hir::Variant<'_>]) {
929 let def = tcx.adt_def(def_id);
930 let repr_type = def.repr.discr_type();
931 let initial = repr_type.initial_discriminant(tcx);
932 let mut prev_discr = None::<Discr<'_>>;
934 // fill the discriminant values and field types
935 for variant in variants {
936 let wrapped_discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
938 if let Some(ref e) = variant.disr_expr {
939 let expr_did = tcx.hir().local_def_id(e.hir_id);
940 def.eval_explicit_discr(tcx, expr_did.to_def_id())
941 } else if let Some(discr) = repr_type.disr_incr(tcx, prev_discr) {
944 struct_span_err!(tcx.sess, variant.span, E0370, "enum discriminant overflowed")
947 format!("overflowed on value after {}", prev_discr.unwrap()),
950 "explicitly set `{} = {}` if that is desired outcome",
951 variant.ident, wrapped_discr
956 .unwrap_or(wrapped_discr),
959 for f in variant.data.fields() {
960 let def_id = tcx.hir().local_def_id(f.hir_id);
961 tcx.ensure().generics_of(def_id);
962 tcx.ensure().type_of(def_id);
963 tcx.ensure().predicates_of(def_id);
966 // Convert the ctor, if any. This also registers the variant as
968 if let Some(ctor_hir_id) = variant.data.ctor_hir_id() {
969 convert_variant_ctor(tcx, ctor_hir_id);
976 variant_did: Option<LocalDefId>,
977 ctor_did: Option<LocalDefId>,
979 discr: ty::VariantDiscr,
980 def: &hir::VariantData<'_>,
981 adt_kind: ty::AdtKind,
982 parent_did: LocalDefId,
983 ) -> ty::VariantDef {
984 let mut seen_fields: FxHashMap<Ident, Span> = Default::default();
989 let fid = tcx.hir().local_def_id(f.hir_id);
990 let dup_span = seen_fields.get(&f.ident.normalize_to_macros_2_0()).cloned();
991 if let Some(prev_span) = dup_span {
992 tcx.sess.emit_err(errors::FieldAlreadyDeclared {
998 seen_fields.insert(f.ident.normalize_to_macros_2_0(), f.span);
1001 ty::FieldDef { did: fid.to_def_id(), ident: f.ident, vis: tcx.visibility(fid) }
1004 let recovered = match def {
1005 hir::VariantData::Struct(_, r) => *r,
1008 ty::VariantDef::new(
1010 variant_did.map(LocalDefId::to_def_id),
1011 ctor_did.map(LocalDefId::to_def_id),
1014 CtorKind::from_hir(def),
1016 parent_did.to_def_id(),
1018 adt_kind == AdtKind::Struct && tcx.has_attr(parent_did.to_def_id(), sym::non_exhaustive)
1019 || variant_did.map_or(false, |variant_did| {
1020 tcx.has_attr(variant_did.to_def_id(), sym::non_exhaustive)
1025 fn adt_def(tcx: TyCtxt<'_>, def_id: DefId) -> &ty::AdtDef {
1028 let def_id = def_id.expect_local();
1029 let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
1030 let item = match tcx.hir().get(hir_id) {
1031 Node::Item(item) => item,
1035 let repr = ReprOptions::new(tcx, def_id.to_def_id());
1036 let (kind, variants) = match item.kind {
1037 ItemKind::Enum(ref def, _) => {
1038 let mut distance_from_explicit = 0;
1043 let variant_did = Some(tcx.hir().local_def_id(v.id));
1045 v.data.ctor_hir_id().map(|hir_id| tcx.hir().local_def_id(hir_id));
1047 let discr = if let Some(ref e) = v.disr_expr {
1048 distance_from_explicit = 0;
1049 ty::VariantDiscr::Explicit(tcx.hir().local_def_id(e.hir_id).to_def_id())
1051 ty::VariantDiscr::Relative(distance_from_explicit)
1053 distance_from_explicit += 1;
1068 (AdtKind::Enum, variants)
1070 ItemKind::Struct(ref def, _) => {
1071 let variant_did = None::<LocalDefId>;
1072 let ctor_did = def.ctor_hir_id().map(|hir_id| tcx.hir().local_def_id(hir_id));
1074 let variants = std::iter::once(convert_variant(
1079 ty::VariantDiscr::Relative(0),
1086 (AdtKind::Struct, variants)
1088 ItemKind::Union(ref def, _) => {
1089 let variant_did = None;
1090 let ctor_did = def.ctor_hir_id().map(|hir_id| tcx.hir().local_def_id(hir_id));
1092 let variants = std::iter::once(convert_variant(
1097 ty::VariantDiscr::Relative(0),
1104 (AdtKind::Union, variants)
1108 tcx.alloc_adt_def(def_id.to_def_id(), kind, variants, repr)
1111 /// Ensures that the super-predicates of the trait with a `DefId`
1112 /// of `trait_def_id` are converted and stored. This also ensures that
1113 /// the transitive super-predicates are converted.
1114 fn super_predicates_of(tcx: TyCtxt<'_>, trait_def_id: DefId) -> ty::GenericPredicates<'_> {
1115 debug!("super_predicates(trait_def_id={:?})", trait_def_id);
1116 tcx.super_predicates_that_define_assoc_type((trait_def_id, None))
1119 /// Ensures that the super-predicates of the trait with a `DefId`
1120 /// of `trait_def_id` are converted and stored. This also ensures that
1121 /// the transitive super-predicates are converted.
1122 fn super_predicates_that_define_assoc_type(
1124 (trait_def_id, assoc_name): (DefId, Option<Ident>),
1125 ) -> ty::GenericPredicates<'_> {
1127 "super_predicates_that_define_assoc_type(trait_def_id={:?}, assoc_name={:?})",
1128 trait_def_id, assoc_name
1130 if trait_def_id.is_local() {
1131 debug!("super_predicates_that_define_assoc_type: local trait_def_id={:?}", trait_def_id);
1132 let trait_hir_id = tcx.hir().local_def_id_to_hir_id(trait_def_id.expect_local());
1134 let item = match tcx.hir().get(trait_hir_id) {
1135 Node::Item(item) => item,
1136 _ => bug!("trait_node_id {} is not an item", trait_hir_id),
1139 let (generics, bounds) = match item.kind {
1140 hir::ItemKind::Trait(.., ref generics, ref supertraits, _) => (generics, supertraits),
1141 hir::ItemKind::TraitAlias(ref generics, ref supertraits) => (generics, supertraits),
1142 _ => span_bug!(item.span, "super_predicates invoked on non-trait"),
1145 let icx = ItemCtxt::new(tcx, trait_def_id);
1147 // Convert the bounds that follow the colon, e.g., `Bar + Zed` in `trait Foo: Bar + Zed`.
1148 let self_param_ty = tcx.types.self_param;
1149 let superbounds1 = if let Some(assoc_name) = assoc_name {
1150 <dyn AstConv<'_>>::compute_bounds_that_match_assoc_type(
1159 <dyn AstConv<'_>>::compute_bounds(
1168 let superbounds1 = superbounds1.predicates(tcx, self_param_ty);
1170 // Convert any explicit superbounds in the where-clause,
1171 // e.g., `trait Foo where Self: Bar`.
1172 // In the case of trait aliases, however, we include all bounds in the where-clause,
1173 // so e.g., `trait Foo = where u32: PartialEq<Self>` would include `u32: PartialEq<Self>`
1174 // as one of its "superpredicates".
1175 let is_trait_alias = tcx.is_trait_alias(trait_def_id);
1176 let superbounds2 = icx.type_parameter_bounds_in_generics(
1180 OnlySelfBounds(!is_trait_alias),
1184 // Combine the two lists to form the complete set of superbounds:
1185 let superbounds = &*tcx.arena.alloc_from_iter(superbounds1.into_iter().chain(superbounds2));
1187 // Now require that immediate supertraits are converted,
1188 // which will, in turn, reach indirect supertraits.
1189 if assoc_name.is_none() {
1190 // Now require that immediate supertraits are converted,
1191 // which will, in turn, reach indirect supertraits.
1192 for &(pred, span) in superbounds {
1193 debug!("superbound: {:?}", pred);
1194 if let ty::PredicateKind::Trait(bound, _) = pred.kind().skip_binder() {
1195 tcx.at(span).super_predicates_of(bound.def_id());
1200 ty::GenericPredicates { parent: None, predicates: superbounds }
1202 // if `assoc_name` is None, then the query should've been redirected to an
1203 // external provider
1204 assert!(assoc_name.is_some());
1205 tcx.super_predicates_of(trait_def_id)
1209 fn trait_def(tcx: TyCtxt<'_>, def_id: DefId) -> ty::TraitDef {
1210 let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
1211 let item = tcx.hir().expect_item(hir_id);
1213 let (is_auto, unsafety) = match item.kind {
1214 hir::ItemKind::Trait(is_auto, unsafety, ..) => (is_auto == hir::IsAuto::Yes, unsafety),
1215 hir::ItemKind::TraitAlias(..) => (false, hir::Unsafety::Normal),
1216 _ => span_bug!(item.span, "trait_def_of_item invoked on non-trait"),
1219 let paren_sugar = tcx.has_attr(def_id, sym::rustc_paren_sugar);
1220 if paren_sugar && !tcx.features().unboxed_closures {
1224 "the `#[rustc_paren_sugar]` attribute is a temporary means of controlling \
1225 which traits can use parenthetical notation",
1227 .help("add `#![feature(unboxed_closures)]` to the crate attributes to use it")
1231 let is_marker = tcx.has_attr(def_id, sym::marker);
1232 let skip_array_during_method_dispatch =
1233 tcx.has_attr(def_id, sym::rustc_skip_array_during_method_dispatch);
1234 let spec_kind = if tcx.has_attr(def_id, sym::rustc_unsafe_specialization_marker) {
1235 ty::trait_def::TraitSpecializationKind::Marker
1236 } else if tcx.has_attr(def_id, sym::rustc_specialization_trait) {
1237 ty::trait_def::TraitSpecializationKind::AlwaysApplicable
1239 ty::trait_def::TraitSpecializationKind::None
1241 let def_path_hash = tcx.def_path_hash(def_id);
1248 skip_array_during_method_dispatch,
1254 fn has_late_bound_regions<'tcx>(tcx: TyCtxt<'tcx>, node: Node<'tcx>) -> Option<Span> {
1255 struct LateBoundRegionsDetector<'tcx> {
1257 outer_index: ty::DebruijnIndex,
1258 has_late_bound_regions: Option<Span>,
1261 impl Visitor<'tcx> for LateBoundRegionsDetector<'tcx> {
1262 type Map = intravisit::ErasedMap<'tcx>;
1264 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
1265 NestedVisitorMap::None
1268 fn visit_ty(&mut self, ty: &'tcx hir::Ty<'tcx>) {
1269 if self.has_late_bound_regions.is_some() {
1273 hir::TyKind::BareFn(..) => {
1274 self.outer_index.shift_in(1);
1275 intravisit::walk_ty(self, ty);
1276 self.outer_index.shift_out(1);
1278 _ => intravisit::walk_ty(self, ty),
1282 fn visit_poly_trait_ref(
1284 tr: &'tcx hir::PolyTraitRef<'tcx>,
1285 m: hir::TraitBoundModifier,
1287 if self.has_late_bound_regions.is_some() {
1290 self.outer_index.shift_in(1);
1291 intravisit::walk_poly_trait_ref(self, tr, m);
1292 self.outer_index.shift_out(1);
1295 fn visit_lifetime(&mut self, lt: &'tcx hir::Lifetime) {
1296 if self.has_late_bound_regions.is_some() {
1300 match self.tcx.named_region(lt.hir_id) {
1301 Some(rl::Region::Static | rl::Region::EarlyBound(..)) => {}
1303 rl::Region::LateBound(debruijn, _, _, _)
1304 | rl::Region::LateBoundAnon(debruijn, _, _),
1305 ) if debruijn < self.outer_index => {}
1307 rl::Region::LateBound(..)
1308 | rl::Region::LateBoundAnon(..)
1309 | rl::Region::Free(..),
1312 self.has_late_bound_regions = Some(lt.span);
1318 fn has_late_bound_regions<'tcx>(
1320 generics: &'tcx hir::Generics<'tcx>,
1321 decl: &'tcx hir::FnDecl<'tcx>,
1323 let mut visitor = LateBoundRegionsDetector {
1325 outer_index: ty::INNERMOST,
1326 has_late_bound_regions: None,
1328 for param in generics.params {
1329 if let GenericParamKind::Lifetime { .. } = param.kind {
1330 if tcx.is_late_bound(param.hir_id) {
1331 return Some(param.span);
1335 visitor.visit_fn_decl(decl);
1336 visitor.has_late_bound_regions
1340 Node::TraitItem(item) => match item.kind {
1341 hir::TraitItemKind::Fn(ref sig, _) => {
1342 has_late_bound_regions(tcx, &item.generics, &sig.decl)
1346 Node::ImplItem(item) => match item.kind {
1347 hir::ImplItemKind::Fn(ref sig, _) => {
1348 has_late_bound_regions(tcx, &item.generics, &sig.decl)
1352 Node::ForeignItem(item) => match item.kind {
1353 hir::ForeignItemKind::Fn(ref fn_decl, _, ref generics) => {
1354 has_late_bound_regions(tcx, generics, fn_decl)
1358 Node::Item(item) => match item.kind {
1359 hir::ItemKind::Fn(ref sig, .., ref generics, _) => {
1360 has_late_bound_regions(tcx, generics, &sig.decl)
1368 struct AnonConstInParamTyDetector {
1370 found_anon_const_in_param_ty: bool,
1374 impl<'v> Visitor<'v> for AnonConstInParamTyDetector {
1375 type Map = intravisit::ErasedMap<'v>;
1377 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
1378 NestedVisitorMap::None
1381 fn visit_generic_param(&mut self, p: &'v hir::GenericParam<'v>) {
1382 if let GenericParamKind::Const { ref ty, default: _ } = p.kind {
1383 let prev = self.in_param_ty;
1384 self.in_param_ty = true;
1386 self.in_param_ty = prev;
1390 fn visit_anon_const(&mut self, c: &'v hir::AnonConst) {
1391 if self.in_param_ty && self.ct == c.hir_id {
1392 self.found_anon_const_in_param_ty = true;
1394 intravisit::walk_anon_const(self, c)
1399 fn generics_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::Generics {
1402 let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
1404 let node = tcx.hir().get(hir_id);
1405 let parent_def_id = match node {
1407 | Node::TraitItem(_)
1410 | Node::Field(_) => {
1411 let parent_id = tcx.hir().get_parent_item(hir_id);
1412 Some(tcx.hir().local_def_id(parent_id).to_def_id())
1414 // FIXME(#43408) always enable this once `lazy_normalization` is
1415 // stable enough and does not need a feature gate anymore.
1416 Node::AnonConst(_) => {
1417 let parent_id = tcx.hir().get_parent_item(hir_id);
1418 let parent_def_id = tcx.hir().local_def_id(parent_id);
1420 let mut in_param_ty = false;
1421 for (_parent, node) in tcx.hir().parent_iter(hir_id) {
1422 if let Some(generics) = node.generics() {
1423 let mut visitor = AnonConstInParamTyDetector {
1425 found_anon_const_in_param_ty: false,
1429 visitor.visit_generics(generics);
1430 in_param_ty = visitor.found_anon_const_in_param_ty;
1436 // We do not allow generic parameters in anon consts if we are inside
1437 // of a const parameter type, e.g. `struct Foo<const N: usize, const M: [u8; N]>` is not allowed.
1439 } else if tcx.lazy_normalization() {
1440 // HACK(eddyb) this provides the correct generics when
1441 // `feature(const_generics)` is enabled, so that const expressions
1442 // used with const generics, e.g. `Foo<{N+1}>`, can work at all.
1444 // Note that we do not supply the parent generics when using
1445 // `min_const_generics`.
1446 Some(parent_def_id.to_def_id())
1448 let parent_node = tcx.hir().get(tcx.hir().get_parent_node(hir_id));
1450 // HACK(eddyb) this provides the correct generics for repeat
1451 // expressions' count (i.e. `N` in `[x; N]`), and explicit
1452 // `enum` discriminants (i.e. `D` in `enum Foo { Bar = D }`),
1453 // as they shouldn't be able to cause query cycle errors.
1454 Node::Expr(&Expr { kind: ExprKind::Repeat(_, ref constant), .. })
1455 | Node::Variant(Variant { disr_expr: Some(ref constant), .. })
1456 if constant.hir_id == hir_id =>
1458 Some(parent_def_id.to_def_id())
1465 Node::Expr(&hir::Expr { kind: hir::ExprKind::Closure(..), .. }) => {
1466 Some(tcx.closure_base_def_id(def_id))
1468 Node::Item(item) => match item.kind {
1469 ItemKind::OpaqueTy(hir::OpaqueTy { impl_trait_fn, .. }) => {
1470 impl_trait_fn.or_else(|| {
1471 let parent_id = tcx.hir().get_parent_item(hir_id);
1472 assert!(parent_id != hir_id && parent_id != CRATE_HIR_ID);
1473 debug!("generics_of: parent of opaque ty {:?} is {:?}", def_id, parent_id);
1474 // Opaque types are always nested within another item, and
1475 // inherit the generics of the item.
1476 Some(tcx.hir().local_def_id(parent_id).to_def_id())
1484 let mut opt_self = None;
1485 let mut allow_defaults = false;
1487 let no_generics = hir::Generics::empty();
1488 let ast_generics = match node {
1489 Node::TraitItem(item) => &item.generics,
1491 Node::ImplItem(item) => &item.generics,
1493 Node::Item(item) => {
1495 ItemKind::Fn(.., ref generics, _)
1496 | ItemKind::Impl(hir::Impl { ref generics, .. }) => generics,
1498 ItemKind::TyAlias(_, ref generics)
1499 | ItemKind::Enum(_, ref generics)
1500 | ItemKind::Struct(_, ref generics)
1501 | ItemKind::OpaqueTy(hir::OpaqueTy { ref generics, .. })
1502 | ItemKind::Union(_, ref generics) => {
1503 allow_defaults = true;
1507 ItemKind::Trait(_, _, ref generics, ..)
1508 | ItemKind::TraitAlias(ref generics, ..) => {
1509 // Add in the self type parameter.
1511 // Something of a hack: use the node id for the trait, also as
1512 // the node id for the Self type parameter.
1513 let param_id = item.def_id;
1515 opt_self = Some(ty::GenericParamDef {
1517 name: kw::SelfUpper,
1518 def_id: param_id.to_def_id(),
1519 pure_wrt_drop: false,
1520 kind: ty::GenericParamDefKind::Type {
1522 object_lifetime_default: rl::Set1::Empty,
1527 allow_defaults = true;
1535 Node::ForeignItem(item) => match item.kind {
1536 ForeignItemKind::Static(..) => &no_generics,
1537 ForeignItemKind::Fn(_, _, ref generics) => generics,
1538 ForeignItemKind::Type => &no_generics,
1544 let has_self = opt_self.is_some();
1545 let mut parent_has_self = false;
1546 let mut own_start = has_self as u32;
1547 let parent_count = parent_def_id.map_or(0, |def_id| {
1548 let generics = tcx.generics_of(def_id);
1549 assert_eq!(has_self, false);
1550 parent_has_self = generics.has_self;
1551 own_start = generics.count() as u32;
1552 generics.parent_count + generics.params.len()
1555 let mut params: Vec<_> = Vec::with_capacity(ast_generics.params.len() + has_self as usize);
1557 if let Some(opt_self) = opt_self {
1558 params.push(opt_self);
1561 let early_lifetimes = early_bound_lifetimes_from_generics(tcx, ast_generics);
1562 params.extend(early_lifetimes.enumerate().map(|(i, param)| ty::GenericParamDef {
1563 name: param.name.ident().name,
1564 index: own_start + i as u32,
1565 def_id: tcx.hir().local_def_id(param.hir_id).to_def_id(),
1566 pure_wrt_drop: param.pure_wrt_drop,
1567 kind: ty::GenericParamDefKind::Lifetime,
1570 let object_lifetime_defaults = tcx.object_lifetime_defaults(hir_id);
1572 // Now create the real type and const parameters.
1573 let type_start = own_start - has_self as u32 + params.len() as u32;
1576 params.extend(ast_generics.params.iter().filter_map(|param| match param.kind {
1577 GenericParamKind::Lifetime { .. } => None,
1578 GenericParamKind::Type { ref default, synthetic, .. } => {
1579 if !allow_defaults && default.is_some() {
1580 if !tcx.features().default_type_parameter_fallback {
1581 tcx.struct_span_lint_hir(
1582 lint::builtin::INVALID_TYPE_PARAM_DEFAULT,
1587 "defaults for type parameters are only allowed in \
1588 `struct`, `enum`, `type`, or `trait` definitions",
1596 let kind = ty::GenericParamDefKind::Type {
1597 has_default: default.is_some(),
1598 object_lifetime_default: object_lifetime_defaults
1600 .map_or(rl::Set1::Empty, |o| o[i]),
1604 let param_def = ty::GenericParamDef {
1605 index: type_start + i as u32,
1606 name: param.name.ident().name,
1607 def_id: tcx.hir().local_def_id(param.hir_id).to_def_id(),
1608 pure_wrt_drop: param.pure_wrt_drop,
1614 GenericParamKind::Const { default, .. } => {
1615 if !allow_defaults && default.is_some() {
1618 "defaults for const parameters are only allowed in \
1619 `struct`, `enum`, `type`, or `trait` definitions",
1623 let param_def = ty::GenericParamDef {
1624 index: type_start + i as u32,
1625 name: param.name.ident().name,
1626 def_id: tcx.hir().local_def_id(param.hir_id).to_def_id(),
1627 pure_wrt_drop: param.pure_wrt_drop,
1628 kind: ty::GenericParamDefKind::Const { has_default: default.is_some() },
1635 // provide junk type parameter defs - the only place that
1636 // cares about anything but the length is instantiation,
1637 // and we don't do that for closures.
1638 if let Node::Expr(&hir::Expr { kind: hir::ExprKind::Closure(.., gen), .. }) = node {
1639 let dummy_args = if gen.is_some() {
1640 &["<resume_ty>", "<yield_ty>", "<return_ty>", "<witness>", "<upvars>"][..]
1642 &["<closure_kind>", "<closure_signature>", "<upvars>"][..]
1645 params.extend(dummy_args.iter().enumerate().map(|(i, &arg)| ty::GenericParamDef {
1646 index: type_start + i as u32,
1647 name: Symbol::intern(arg),
1649 pure_wrt_drop: false,
1650 kind: ty::GenericParamDefKind::Type {
1652 object_lifetime_default: rl::Set1::Empty,
1658 let param_def_id_to_index = params.iter().map(|param| (param.def_id, param.index)).collect();
1661 parent: parent_def_id,
1664 param_def_id_to_index,
1665 has_self: has_self || parent_has_self,
1666 has_late_bound_regions: has_late_bound_regions(tcx, node),
1670 fn are_suggestable_generic_args(generic_args: &[hir::GenericArg<'_>]) -> bool {
1673 .filter_map(|arg| match arg {
1674 hir::GenericArg::Type(ty) => Some(ty),
1677 .any(is_suggestable_infer_ty)
1680 /// Whether `ty` is a type with `_` placeholders that can be inferred. Used in diagnostics only to
1681 /// use inference to provide suggestions for the appropriate type if possible.
1682 fn is_suggestable_infer_ty(ty: &hir::Ty<'_>) -> bool {
1686 Slice(ty) | Array(ty, _) => is_suggestable_infer_ty(ty),
1687 Tup(tys) => tys.iter().any(is_suggestable_infer_ty),
1688 Ptr(mut_ty) | Rptr(_, mut_ty) => is_suggestable_infer_ty(mut_ty.ty),
1689 OpaqueDef(_, generic_args) => are_suggestable_generic_args(generic_args),
1690 Path(hir::QPath::TypeRelative(ty, segment)) => {
1691 is_suggestable_infer_ty(ty) || are_suggestable_generic_args(segment.args().args)
1693 Path(hir::QPath::Resolved(ty_opt, hir::Path { segments, .. })) => {
1694 ty_opt.map_or(false, is_suggestable_infer_ty)
1695 || segments.iter().any(|segment| are_suggestable_generic_args(segment.args().args))
1701 pub fn get_infer_ret_ty(output: &'hir hir::FnRetTy<'hir>) -> Option<&'hir hir::Ty<'hir>> {
1702 if let hir::FnRetTy::Return(ref ty) = output {
1703 if is_suggestable_infer_ty(ty) {
1710 fn fn_sig(tcx: TyCtxt<'_>, def_id: DefId) -> ty::PolyFnSig<'_> {
1711 use rustc_hir::Node::*;
1714 let def_id = def_id.expect_local();
1715 let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
1717 let icx = ItemCtxt::new(tcx, def_id.to_def_id());
1719 match tcx.hir().get(hir_id) {
1720 TraitItem(hir::TraitItem {
1721 kind: TraitItemKind::Fn(sig, TraitFn::Provided(_)),
1726 | ImplItem(hir::ImplItem { kind: ImplItemKind::Fn(sig, _), ident, generics, .. })
1727 | Item(hir::Item { kind: ItemKind::Fn(sig, generics, _), ident, .. }) => {
1728 match get_infer_ret_ty(&sig.decl.output) {
1730 let fn_sig = tcx.typeck(def_id).liberated_fn_sigs()[hir_id];
1731 // Typeck doesn't expect erased regions to be returned from `type_of`.
1732 let fn_sig = tcx.fold_regions(fn_sig, &mut false, |r, _| match r {
1733 ty::ReErased => tcx.lifetimes.re_static,
1736 let fn_sig = ty::Binder::dummy(fn_sig);
1738 let mut visitor = PlaceholderHirTyCollector::default();
1739 visitor.visit_ty(ty);
1740 let mut diag = bad_placeholder_type(tcx, visitor.0, "return type");
1741 let ret_ty = fn_sig.skip_binder().output();
1742 if ret_ty != tcx.ty_error() {
1743 if !ret_ty.is_closure() {
1744 let ret_ty_str = match ret_ty.kind() {
1745 // Suggest a function pointer return type instead of a unique function definition
1746 // (e.g. `fn() -> i32` instead of `fn() -> i32 { f }`, the latter of which is invalid
1748 ty::FnDef(..) => ret_ty.fn_sig(tcx).to_string(),
1749 _ => ret_ty.to_string(),
1751 diag.span_suggestion(
1753 "replace with the correct return type",
1755 Applicability::MaybeIncorrect,
1758 // We're dealing with a closure, so we should suggest using `impl Fn` or trait bounds
1759 // to prevent the user from getting a papercut while trying to use the unique closure
1760 // syntax (e.g. `[closure@src/lib.rs:2:5: 2:9]`).
1761 diag.help("consider using an `Fn`, `FnMut`, or `FnOnce` trait bound");
1762 diag.note("for more information on `Fn` traits and closure types, see https://doc.rust-lang.org/book/ch13-01-closures.html");
1769 None => <dyn AstConv<'_>>::ty_of_fn(
1772 sig.header.unsafety,
1782 TraitItem(hir::TraitItem {
1783 kind: TraitItemKind::Fn(FnSig { header, decl, span: _ }, _),
1787 }) => <dyn AstConv<'_>>::ty_of_fn(
1798 ForeignItem(&hir::ForeignItem {
1799 kind: ForeignItemKind::Fn(ref fn_decl, _, _),
1803 let abi = tcx.hir().get_foreign_abi(hir_id);
1804 compute_sig_of_foreign_fn_decl(tcx, def_id.to_def_id(), fn_decl, abi, ident)
1807 Ctor(data) | Variant(hir::Variant { data, .. }) if data.ctor_hir_id().is_some() => {
1808 let ty = tcx.type_of(tcx.hir().get_parent_did(hir_id).to_def_id());
1810 data.fields().iter().map(|f| tcx.type_of(tcx.hir().local_def_id(f.hir_id)));
1811 ty::Binder::dummy(tcx.mk_fn_sig(
1815 hir::Unsafety::Normal,
1820 Expr(&hir::Expr { kind: hir::ExprKind::Closure(..), .. }) => {
1821 // Closure signatures are not like other function
1822 // signatures and cannot be accessed through `fn_sig`. For
1823 // example, a closure signature excludes the `self`
1824 // argument. In any case they are embedded within the
1825 // closure type as part of the `ClosureSubsts`.
1827 // To get the signature of a closure, you should use the
1828 // `sig` method on the `ClosureSubsts`:
1830 // substs.as_closure().sig(def_id, tcx)
1832 "to get the signature of a closure, use `substs.as_closure().sig()` not `fn_sig()`",
1837 bug!("unexpected sort of node in fn_sig(): {:?}", x);
1842 fn impl_trait_ref(tcx: TyCtxt<'_>, def_id: DefId) -> Option<ty::TraitRef<'_>> {
1843 let icx = ItemCtxt::new(tcx, def_id);
1845 let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
1846 match tcx.hir().expect_item(hir_id).kind {
1847 hir::ItemKind::Impl(ref impl_) => impl_.of_trait.as_ref().map(|ast_trait_ref| {
1848 let selfty = tcx.type_of(def_id);
1849 <dyn AstConv<'_>>::instantiate_mono_trait_ref(&icx, ast_trait_ref, selfty)
1855 fn impl_polarity(tcx: TyCtxt<'_>, def_id: DefId) -> ty::ImplPolarity {
1856 let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
1857 let is_rustc_reservation = tcx.has_attr(def_id, sym::rustc_reservation_impl);
1858 let item = tcx.hir().expect_item(hir_id);
1860 hir::ItemKind::Impl(hir::Impl {
1861 polarity: hir::ImplPolarity::Negative(span),
1865 if is_rustc_reservation {
1866 let span = span.to(of_trait.as_ref().map_or(*span, |t| t.path.span));
1867 tcx.sess.span_err(span, "reservation impls can't be negative");
1869 ty::ImplPolarity::Negative
1871 hir::ItemKind::Impl(hir::Impl {
1872 polarity: hir::ImplPolarity::Positive,
1876 if is_rustc_reservation {
1877 tcx.sess.span_err(item.span, "reservation impls can't be inherent");
1879 ty::ImplPolarity::Positive
1881 hir::ItemKind::Impl(hir::Impl {
1882 polarity: hir::ImplPolarity::Positive,
1886 if is_rustc_reservation {
1887 ty::ImplPolarity::Reservation
1889 ty::ImplPolarity::Positive
1892 item => bug!("impl_polarity: {:?} not an impl", item),
1896 /// Returns the early-bound lifetimes declared in this generics
1897 /// listing. For anything other than fns/methods, this is just all
1898 /// the lifetimes that are declared. For fns or methods, we have to
1899 /// screen out those that do not appear in any where-clauses etc using
1900 /// `resolve_lifetime::early_bound_lifetimes`.
1901 fn early_bound_lifetimes_from_generics<'a, 'tcx: 'a>(
1903 generics: &'a hir::Generics<'a>,
1904 ) -> impl Iterator<Item = &'a hir::GenericParam<'a>> + Captures<'tcx> {
1905 generics.params.iter().filter(move |param| match param.kind {
1906 GenericParamKind::Lifetime { .. } => !tcx.is_late_bound(param.hir_id),
1911 /// Returns a list of type predicates for the definition with ID `def_id`, including inferred
1912 /// lifetime constraints. This includes all predicates returned by `explicit_predicates_of`, plus
1913 /// inferred constraints concerning which regions outlive other regions.
1914 fn predicates_defined_on(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicates<'_> {
1915 debug!("predicates_defined_on({:?})", def_id);
1916 let mut result = tcx.explicit_predicates_of(def_id);
1917 debug!("predicates_defined_on: explicit_predicates_of({:?}) = {:?}", def_id, result,);
1918 let inferred_outlives = tcx.inferred_outlives_of(def_id);
1919 if !inferred_outlives.is_empty() {
1921 "predicates_defined_on: inferred_outlives_of({:?}) = {:?}",
1922 def_id, inferred_outlives,
1924 if result.predicates.is_empty() {
1925 result.predicates = inferred_outlives;
1927 result.predicates = tcx
1929 .alloc_from_iter(result.predicates.iter().chain(inferred_outlives).copied());
1933 debug!("predicates_defined_on({:?}) = {:?}", def_id, result);
1937 /// Returns a list of all type predicates (explicit and implicit) for the definition with
1938 /// ID `def_id`. This includes all predicates returned by `predicates_defined_on`, plus
1939 /// `Self: Trait` predicates for traits.
1940 fn predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicates<'_> {
1941 let mut result = tcx.predicates_defined_on(def_id);
1943 if tcx.is_trait(def_id) {
1944 // For traits, add `Self: Trait` predicate. This is
1945 // not part of the predicates that a user writes, but it
1946 // is something that one must prove in order to invoke a
1947 // method or project an associated type.
1949 // In the chalk setup, this predicate is not part of the
1950 // "predicates" for a trait item. But it is useful in
1951 // rustc because if you directly (e.g.) invoke a trait
1952 // method like `Trait::method(...)`, you must naturally
1953 // prove that the trait applies to the types that were
1954 // used, and adding the predicate into this list ensures
1955 // that this is done.
1956 let span = tcx.sess.source_map().guess_head_span(tcx.def_span(def_id));
1958 tcx.arena.alloc_from_iter(result.predicates.iter().copied().chain(std::iter::once((
1959 ty::TraitRef::identity(tcx, def_id).without_const().to_predicate(tcx),
1963 debug!("predicates_of(def_id={:?}) = {:?}", def_id, result);
1967 /// Returns a list of user-specified type predicates for the definition with ID `def_id`.
1968 /// N.B., this does not include any implied/inferred constraints.
1969 fn gather_explicit_predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicates<'_> {
1972 debug!("explicit_predicates_of(def_id={:?})", def_id);
1974 let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
1975 let node = tcx.hir().get(hir_id);
1977 let mut is_trait = None;
1978 let mut is_default_impl_trait = None;
1980 let icx = ItemCtxt::new(tcx, def_id);
1981 let constness = icx.default_constness_for_trait_bounds();
1983 const NO_GENERICS: &hir::Generics<'_> = &hir::Generics::empty();
1985 // We use an `IndexSet` to preserves order of insertion.
1986 // Preserving the order of insertion is important here so as not to break UI tests.
1987 let mut predicates: FxIndexSet<(ty::Predicate<'_>, Span)> = FxIndexSet::default();
1989 let ast_generics = match node {
1990 Node::TraitItem(item) => &item.generics,
1992 Node::ImplItem(item) => &item.generics,
1994 Node::Item(item) => {
1996 ItemKind::Impl(ref impl_) => {
1997 if impl_.defaultness.is_default() {
1998 is_default_impl_trait = tcx.impl_trait_ref(def_id);
2002 ItemKind::Fn(.., ref generics, _)
2003 | ItemKind::TyAlias(_, ref generics)
2004 | ItemKind::Enum(_, ref generics)
2005 | ItemKind::Struct(_, ref generics)
2006 | ItemKind::Union(_, ref generics) => generics,
2008 ItemKind::Trait(_, _, ref generics, ..) => {
2009 is_trait = Some(ty::TraitRef::identity(tcx, def_id));
2012 ItemKind::TraitAlias(ref generics, _) => {
2013 is_trait = Some(ty::TraitRef::identity(tcx, def_id));
2016 ItemKind::OpaqueTy(OpaqueTy {
2022 if impl_trait_fn.is_some() {
2023 // return-position impl trait
2025 // We don't inherit predicates from the parent here:
2026 // If we have, say `fn f<'a, T: 'a>() -> impl Sized {}`
2027 // then the return type is `f::<'static, T>::{{opaque}}`.
2029 // If we inherited the predicates of `f` then we would
2030 // require that `T: 'static` to show that the return
2031 // type is well-formed.
2033 // The only way to have something with this opaque type
2034 // is from the return type of the containing function,
2035 // which will ensure that the function's predicates
2037 return ty::GenericPredicates { parent: None, predicates: &[] };
2039 // type-alias impl trait
2048 Node::ForeignItem(item) => match item.kind {
2049 ForeignItemKind::Static(..) => NO_GENERICS,
2050 ForeignItemKind::Fn(_, _, ref generics) => generics,
2051 ForeignItemKind::Type => NO_GENERICS,
2057 let generics = tcx.generics_of(def_id);
2058 let parent_count = generics.parent_count as u32;
2059 let has_own_self = generics.has_self && parent_count == 0;
2061 // Below we'll consider the bounds on the type parameters (including `Self`)
2062 // and the explicit where-clauses, but to get the full set of predicates
2063 // on a trait we need to add in the supertrait bounds and bounds found on
2064 // associated types.
2065 if let Some(_trait_ref) = is_trait {
2066 predicates.extend(tcx.super_predicates_of(def_id).predicates.iter().cloned());
2069 // In default impls, we can assume that the self type implements
2070 // the trait. So in:
2072 // default impl Foo for Bar { .. }
2074 // we add a default where clause `Foo: Bar`. We do a similar thing for traits
2075 // (see below). Recall that a default impl is not itself an impl, but rather a
2076 // set of defaults that can be incorporated into another impl.
2077 if let Some(trait_ref) = is_default_impl_trait {
2079 trait_ref.to_poly_trait_ref().without_const().to_predicate(tcx),
2080 tcx.def_span(def_id),
2084 // Collect the region predicates that were declared inline as
2085 // well. In the case of parameters declared on a fn or method, we
2086 // have to be careful to only iterate over early-bound regions.
2087 let mut index = parent_count + has_own_self as u32;
2088 for param in early_bound_lifetimes_from_generics(tcx, ast_generics) {
2089 let region = tcx.mk_region(ty::ReEarlyBound(ty::EarlyBoundRegion {
2090 def_id: tcx.hir().local_def_id(param.hir_id).to_def_id(),
2092 name: param.name.ident().name,
2097 GenericParamKind::Lifetime { .. } => {
2098 param.bounds.iter().for_each(|bound| match bound {
2099 hir::GenericBound::Outlives(lt) => {
2100 let bound = <dyn AstConv<'_>>::ast_region_to_region(&icx, <, None);
2101 let outlives = ty::Binder::dummy(ty::OutlivesPredicate(region, bound));
2102 predicates.insert((outlives.to_predicate(tcx), lt.span));
2111 // Collect the predicates that were written inline by the user on each
2112 // type parameter (e.g., `<T: Foo>`).
2113 for param in ast_generics.params {
2115 // We already dealt with early bound lifetimes above.
2116 GenericParamKind::Lifetime { .. } => (),
2117 GenericParamKind::Type { .. } => {
2118 let name = param.name.ident().name;
2119 let param_ty = ty::ParamTy::new(index, name).to_ty(tcx);
2122 let sized = SizedByDefault::Yes;
2123 let bounds = <dyn AstConv<'_>>::compute_bounds(
2130 predicates.extend(bounds.predicates(tcx, param_ty));
2132 GenericParamKind::Const { .. } => {
2133 // Bounds on const parameters are currently not possible.
2134 debug_assert!(param.bounds.is_empty());
2140 // Add in the bounds that appear in the where-clause.
2141 let where_clause = &ast_generics.where_clause;
2142 for predicate in where_clause.predicates {
2144 hir::WherePredicate::BoundPredicate(bound_pred) => {
2145 let ty = icx.to_ty(&bound_pred.bounded_ty);
2146 let bound_vars = icx.tcx.late_bound_vars(bound_pred.bounded_ty.hir_id);
2148 // Keep the type around in a dummy predicate, in case of no bounds.
2149 // That way, `where Ty:` is not a complete noop (see #53696) and `Ty`
2150 // is still checked for WF.
2151 if bound_pred.bounds.is_empty() {
2152 if let ty::Param(_) = ty.kind() {
2153 // This is a `where T:`, which can be in the HIR from the
2154 // transformation that moves `?Sized` to `T`'s declaration.
2155 // We can skip the predicate because type parameters are
2156 // trivially WF, but also we *should*, to avoid exposing
2157 // users who never wrote `where Type:,` themselves, to
2158 // compiler/tooling bugs from not handling WF predicates.
2160 let span = bound_pred.bounded_ty.span;
2161 let re_root_empty = tcx.lifetimes.re_root_empty;
2162 let predicate = ty::Binder::bind_with_vars(
2163 ty::PredicateKind::TypeOutlives(ty::OutlivesPredicate(
2169 predicates.insert((predicate.to_predicate(tcx), span));
2173 for bound in bound_pred.bounds.iter() {
2175 hir::GenericBound::Trait(poly_trait_ref, modifier) => {
2176 let constness = match modifier {
2177 hir::TraitBoundModifier::MaybeConst => hir::Constness::NotConst,
2178 hir::TraitBoundModifier::None => constness,
2179 hir::TraitBoundModifier::Maybe => bug!("this wasn't handled"),
2182 let mut bounds = Bounds::default();
2183 let _ = <dyn AstConv<'_>>::instantiate_poly_trait_ref(
2185 &poly_trait_ref.trait_ref,
2186 poly_trait_ref.span,
2192 predicates.extend(bounds.predicates(tcx, ty));
2195 &hir::GenericBound::LangItemTrait(lang_item, span, hir_id, args) => {
2196 let mut bounds = Bounds::default();
2197 <dyn AstConv<'_>>::instantiate_lang_item_trait_ref(
2206 predicates.extend(bounds.predicates(tcx, ty));
2209 hir::GenericBound::Outlives(lifetime) => {
2211 <dyn AstConv<'_>>::ast_region_to_region(&icx, lifetime, None);
2213 ty::Binder::bind_with_vars(
2214 ty::PredicateKind::TypeOutlives(ty::OutlivesPredicate(
2227 hir::WherePredicate::RegionPredicate(region_pred) => {
2228 let r1 = <dyn AstConv<'_>>::ast_region_to_region(&icx, ®ion_pred.lifetime, None);
2229 predicates.extend(region_pred.bounds.iter().map(|bound| {
2230 let (r2, span) = match bound {
2231 hir::GenericBound::Outlives(lt) => {
2232 (<dyn AstConv<'_>>::ast_region_to_region(&icx, lt, None), lt.span)
2236 let pred = ty::PredicateKind::RegionOutlives(ty::OutlivesPredicate(r1, r2))
2237 .to_predicate(icx.tcx);
2243 hir::WherePredicate::EqPredicate(..) => {
2249 if tcx.features().const_evaluatable_checked {
2250 predicates.extend(const_evaluatable_predicates_of(tcx, def_id.expect_local()));
2253 let mut predicates: Vec<_> = predicates.into_iter().collect();
2255 // Subtle: before we store the predicates into the tcx, we
2256 // sort them so that predicates like `T: Foo<Item=U>` come
2257 // before uses of `U`. This avoids false ambiguity errors
2258 // in trait checking. See `setup_constraining_predicates`
2260 if let Node::Item(&Item { kind: ItemKind::Impl { .. }, .. }) = node {
2261 let self_ty = tcx.type_of(def_id);
2262 let trait_ref = tcx.impl_trait_ref(def_id);
2263 cgp::setup_constraining_predicates(
2267 &mut cgp::parameters_for_impl(self_ty, trait_ref),
2271 let result = ty::GenericPredicates {
2272 parent: generics.parent,
2273 predicates: tcx.arena.alloc_from_iter(predicates),
2275 debug!("explicit_predicates_of(def_id={:?}) = {:?}", def_id, result);
2279 fn const_evaluatable_predicates_of<'tcx>(
2282 ) -> FxIndexSet<(ty::Predicate<'tcx>, Span)> {
2283 struct ConstCollector<'tcx> {
2285 preds: FxIndexSet<(ty::Predicate<'tcx>, Span)>,
2288 impl<'tcx> intravisit::Visitor<'tcx> for ConstCollector<'tcx> {
2289 type Map = Map<'tcx>;
2291 fn nested_visit_map(&mut self) -> intravisit::NestedVisitorMap<Self::Map> {
2292 intravisit::NestedVisitorMap::None
2295 fn visit_anon_const(&mut self, c: &'tcx hir::AnonConst) {
2296 let def_id = self.tcx.hir().local_def_id(c.hir_id);
2297 let ct = ty::Const::from_anon_const(self.tcx, def_id);
2298 if let ty::ConstKind::Unevaluated(uv) = ct.val {
2299 assert_eq!(uv.promoted, None);
2300 let span = self.tcx.hir().span(c.hir_id);
2302 ty::PredicateKind::ConstEvaluatable(uv.def, uv.substs).to_predicate(self.tcx),
2308 fn visit_const_param_default(&mut self, _param: HirId, _ct: &'tcx hir::AnonConst) {
2309 // Do not look into const param defaults,
2310 // these get checked when they are actually instantiated.
2312 // We do not want the following to error:
2314 // struct Foo<const N: usize, const M: usize = { N + 1 }>;
2315 // struct Bar<const N: usize>(Foo<N, 3>);
2319 let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
2320 let node = tcx.hir().get(hir_id);
2322 let mut collector = ConstCollector { tcx, preds: FxIndexSet::default() };
2323 if let hir::Node::Item(item) = node {
2324 if let hir::ItemKind::Impl(ref impl_) = item.kind {
2325 if let Some(of_trait) = &impl_.of_trait {
2326 debug!("const_evaluatable_predicates_of({:?}): visit impl trait_ref", def_id);
2327 collector.visit_trait_ref(of_trait);
2330 debug!("const_evaluatable_predicates_of({:?}): visit_self_ty", def_id);
2331 collector.visit_ty(impl_.self_ty);
2335 if let Some(generics) = node.generics() {
2336 debug!("const_evaluatable_predicates_of({:?}): visit_generics", def_id);
2337 collector.visit_generics(generics);
2340 if let Some(fn_sig) = tcx.hir().fn_sig_by_hir_id(hir_id) {
2341 debug!("const_evaluatable_predicates_of({:?}): visit_fn_decl", def_id);
2342 collector.visit_fn_decl(fn_sig.decl);
2344 debug!("const_evaluatable_predicates_of({:?}) = {:?}", def_id, collector.preds);
2349 fn trait_explicit_predicates_and_bounds(
2352 ) -> ty::GenericPredicates<'_> {
2353 assert_eq!(tcx.def_kind(def_id), DefKind::Trait);
2354 gather_explicit_predicates_of(tcx, def_id.to_def_id())
2357 fn explicit_predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicates<'_> {
2358 if let DefKind::Trait = tcx.def_kind(def_id) {
2359 // Remove bounds on associated types from the predicates, they will be
2360 // returned by `explicit_item_bounds`.
2361 let predicates_and_bounds = tcx.trait_explicit_predicates_and_bounds(def_id.expect_local());
2362 let trait_identity_substs = InternalSubsts::identity_for_item(tcx, def_id);
2364 let is_assoc_item_ty = |ty: Ty<'_>| {
2365 // For a predicate from a where clause to become a bound on an
2367 // * It must use the identity substs of the item.
2368 // * Since any generic parameters on the item are not in scope,
2369 // this means that the item is not a GAT, and its identity
2370 // substs are the same as the trait's.
2371 // * It must be an associated type for this trait (*not* a
2373 if let ty::Projection(projection) = ty.kind() {
2374 projection.substs == trait_identity_substs
2375 && tcx.associated_item(projection.item_def_id).container.id() == def_id
2381 let predicates: Vec<_> = predicates_and_bounds
2385 .filter(|(pred, _)| match pred.kind().skip_binder() {
2386 ty::PredicateKind::Trait(tr, _) => !is_assoc_item_ty(tr.self_ty()),
2387 ty::PredicateKind::Projection(proj) => {
2388 !is_assoc_item_ty(proj.projection_ty.self_ty())
2390 ty::PredicateKind::TypeOutlives(outlives) => !is_assoc_item_ty(outlives.0),
2394 if predicates.len() == predicates_and_bounds.predicates.len() {
2395 predicates_and_bounds
2397 ty::GenericPredicates {
2398 parent: predicates_and_bounds.parent,
2399 predicates: tcx.arena.alloc_slice(&predicates),
2403 gather_explicit_predicates_of(tcx, def_id)
2407 /// Converts a specific `GenericBound` from the AST into a set of
2408 /// predicates that apply to the self type. A vector is returned
2409 /// because this can be anywhere from zero predicates (`T: ?Sized` adds no
2410 /// predicates) to one (`T: Foo`) to many (`T: Bar<X = i32>` adds `T: Bar`
2411 /// and `<T as Bar>::X == i32`).
2412 fn predicates_from_bound<'tcx>(
2413 astconv: &dyn AstConv<'tcx>,
2415 bound: &'tcx hir::GenericBound<'tcx>,
2416 constness: hir::Constness,
2417 ) -> Vec<(ty::Predicate<'tcx>, Span)> {
2419 hir::GenericBound::Trait(ref tr, modifier) => {
2420 let constness = match modifier {
2421 hir::TraitBoundModifier::Maybe => return vec![],
2422 hir::TraitBoundModifier::MaybeConst => hir::Constness::NotConst,
2423 hir::TraitBoundModifier::None => constness,
2426 let mut bounds = Bounds::default();
2427 let _ = astconv.instantiate_poly_trait_ref(
2435 bounds.predicates(astconv.tcx(), param_ty)
2437 hir::GenericBound::LangItemTrait(lang_item, span, hir_id, args) => {
2438 let mut bounds = Bounds::default();
2439 astconv.instantiate_lang_item_trait_ref(
2447 bounds.predicates(astconv.tcx(), param_ty)
2449 hir::GenericBound::Outlives(ref lifetime) => {
2450 let region = astconv.ast_region_to_region(lifetime, None);
2451 let pred = ty::PredicateKind::TypeOutlives(ty::OutlivesPredicate(param_ty, region))
2452 .to_predicate(astconv.tcx());
2453 vec![(pred, lifetime.span)]
2458 fn compute_sig_of_foreign_fn_decl<'tcx>(
2461 decl: &'tcx hir::FnDecl<'tcx>,
2464 ) -> ty::PolyFnSig<'tcx> {
2465 let unsafety = if abi == abi::Abi::RustIntrinsic {
2466 intrinsic_operation_unsafety(tcx.item_name(def_id))
2468 hir::Unsafety::Unsafe
2470 let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
2471 let fty = <dyn AstConv<'_>>::ty_of_fn(
2472 &ItemCtxt::new(tcx, def_id),
2477 &hir::Generics::empty(),
2482 // Feature gate SIMD types in FFI, since I am not sure that the
2483 // ABIs are handled at all correctly. -huonw
2484 if abi != abi::Abi::RustIntrinsic
2485 && abi != abi::Abi::PlatformIntrinsic
2486 && !tcx.features().simd_ffi
2488 let check = |ast_ty: &hir::Ty<'_>, ty: Ty<'_>| {
2493 .span_to_snippet(ast_ty.span)
2494 .map_or_else(|_| String::new(), |s| format!(" `{}`", s));
2499 "use of SIMD type{} in FFI is highly experimental and \
2500 may result in invalid code",
2504 .help("add `#![feature(simd_ffi)]` to the crate attributes to enable")
2508 for (input, ty) in iter::zip(decl.inputs, fty.inputs().skip_binder()) {
2511 if let hir::FnRetTy::Return(ref ty) = decl.output {
2512 check(&ty, fty.output().skip_binder())
2519 fn is_foreign_item(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
2520 match tcx.hir().get_if_local(def_id) {
2521 Some(Node::ForeignItem(..)) => true,
2523 _ => bug!("is_foreign_item applied to non-local def-id {:?}", def_id),
2527 fn static_mutability(tcx: TyCtxt<'_>, def_id: DefId) -> Option<hir::Mutability> {
2528 match tcx.hir().get_if_local(def_id) {
2530 Node::Item(&hir::Item { kind: hir::ItemKind::Static(_, mutbl, _), .. })
2531 | Node::ForeignItem(&hir::ForeignItem {
2532 kind: hir::ForeignItemKind::Static(_, mutbl),
2537 _ => bug!("static_mutability applied to non-local def-id {:?}", def_id),
2541 fn generator_kind(tcx: TyCtxt<'_>, def_id: DefId) -> Option<hir::GeneratorKind> {
2542 match tcx.hir().get_if_local(def_id) {
2543 Some(Node::Expr(&rustc_hir::Expr {
2544 kind: rustc_hir::ExprKind::Closure(_, _, body_id, _, _),
2546 })) => tcx.hir().body(body_id).generator_kind(),
2548 _ => bug!("generator_kind applied to non-local def-id {:?}", def_id),
2552 fn from_target_feature(
2555 attr: &ast::Attribute,
2556 supported_target_features: &FxHashMap<String, Option<Symbol>>,
2557 target_features: &mut Vec<Symbol>,
2559 let list = match attr.meta_item_list() {
2563 let bad_item = |span| {
2564 let msg = "malformed `target_feature` attribute input";
2565 let code = "enable = \"..\"".to_owned();
2567 .struct_span_err(span, &msg)
2568 .span_suggestion(span, "must be of the form", code, Applicability::HasPlaceholders)
2571 let rust_features = tcx.features();
2573 // Only `enable = ...` is accepted in the meta-item list.
2574 if !item.has_name(sym::enable) {
2575 bad_item(item.span());
2579 // Must be of the form `enable = "..."` (a string).
2580 let value = match item.value_str() {
2581 Some(value) => value,
2583 bad_item(item.span());
2588 // We allow comma separation to enable multiple features.
2589 target_features.extend(value.as_str().split(',').filter_map(|feature| {
2590 let feature_gate = match supported_target_features.get(feature) {
2594 format!("the feature named `{}` is not valid for this target", feature);
2595 let mut err = tcx.sess.struct_span_err(item.span(), &msg);
2598 format!("`{}` is not valid for this target", feature),
2600 if let Some(stripped) = feature.strip_prefix('+') {
2601 let valid = supported_target_features.contains_key(stripped);
2603 err.help("consider removing the leading `+` in the feature name");
2611 // Only allow features whose feature gates have been enabled.
2612 let allowed = match feature_gate.as_ref().copied() {
2613 Some(sym::arm_target_feature) => rust_features.arm_target_feature,
2614 Some(sym::aarch64_target_feature) => rust_features.aarch64_target_feature,
2615 Some(sym::hexagon_target_feature) => rust_features.hexagon_target_feature,
2616 Some(sym::powerpc_target_feature) => rust_features.powerpc_target_feature,
2617 Some(sym::mips_target_feature) => rust_features.mips_target_feature,
2618 Some(sym::riscv_target_feature) => rust_features.riscv_target_feature,
2619 Some(sym::avx512_target_feature) => rust_features.avx512_target_feature,
2620 Some(sym::sse4a_target_feature) => rust_features.sse4a_target_feature,
2621 Some(sym::tbm_target_feature) => rust_features.tbm_target_feature,
2622 Some(sym::wasm_target_feature) => rust_features.wasm_target_feature,
2623 Some(sym::cmpxchg16b_target_feature) => rust_features.cmpxchg16b_target_feature,
2624 Some(sym::adx_target_feature) => rust_features.adx_target_feature,
2625 Some(sym::movbe_target_feature) => rust_features.movbe_target_feature,
2626 Some(sym::rtm_target_feature) => rust_features.rtm_target_feature,
2627 Some(sym::f16c_target_feature) => rust_features.f16c_target_feature,
2628 Some(sym::ermsb_target_feature) => rust_features.ermsb_target_feature,
2629 Some(sym::bpf_target_feature) => rust_features.bpf_target_feature,
2630 Some(name) => bug!("unknown target feature gate {}", name),
2633 if !allowed && id.is_local() {
2635 &tcx.sess.parse_sess,
2636 feature_gate.unwrap(),
2638 &format!("the target feature `{}` is currently unstable", feature),
2642 Some(Symbol::intern(feature))
2647 fn linkage_by_name(tcx: TyCtxt<'_>, def_id: DefId, name: &str) -> Linkage {
2648 use rustc_middle::mir::mono::Linkage::*;
2650 // Use the names from src/llvm/docs/LangRef.rst here. Most types are only
2651 // applicable to variable declarations and may not really make sense for
2652 // Rust code in the first place but allow them anyway and trust that the
2653 // user knows what s/he's doing. Who knows, unanticipated use cases may pop
2654 // up in the future.
2656 // ghost, dllimport, dllexport and linkonce_odr_autohide are not supported
2657 // and don't have to be, LLVM treats them as no-ops.
2659 "appending" => Appending,
2660 "available_externally" => AvailableExternally,
2662 "extern_weak" => ExternalWeak,
2663 "external" => External,
2664 "internal" => Internal,
2665 "linkonce" => LinkOnceAny,
2666 "linkonce_odr" => LinkOnceODR,
2667 "private" => Private,
2669 "weak_odr" => WeakODR,
2671 let span = tcx.hir().span_if_local(def_id);
2672 if let Some(span) = span {
2673 tcx.sess.span_fatal(span, "invalid linkage specified")
2675 tcx.sess.fatal(&format!("invalid linkage specified: {}", name))
2681 fn codegen_fn_attrs(tcx: TyCtxt<'_>, id: DefId) -> CodegenFnAttrs {
2682 let attrs = tcx.get_attrs(id);
2684 let mut codegen_fn_attrs = CodegenFnAttrs::new();
2685 if tcx.should_inherit_track_caller(id) {
2686 codegen_fn_attrs.flags |= CodegenFnAttrFlags::TRACK_CALLER;
2689 let supported_target_features = tcx.supported_target_features(LOCAL_CRATE);
2691 let mut inline_span = None;
2692 let mut link_ordinal_span = None;
2693 let mut no_sanitize_span = None;
2694 for attr in attrs.iter() {
2695 if tcx.sess.check_name(attr, sym::cold) {
2696 codegen_fn_attrs.flags |= CodegenFnAttrFlags::COLD;
2697 } else if tcx.sess.check_name(attr, sym::rustc_allocator) {
2698 codegen_fn_attrs.flags |= CodegenFnAttrFlags::ALLOCATOR;
2699 } else if tcx.sess.check_name(attr, sym::unwind) {
2700 codegen_fn_attrs.flags |= CodegenFnAttrFlags::UNWIND;
2701 } else if tcx.sess.check_name(attr, sym::ffi_returns_twice) {
2702 if tcx.is_foreign_item(id) {
2703 codegen_fn_attrs.flags |= CodegenFnAttrFlags::FFI_RETURNS_TWICE;
2705 // `#[ffi_returns_twice]` is only allowed `extern fn`s.
2710 "`#[ffi_returns_twice]` may only be used on foreign functions"
2714 } else if tcx.sess.check_name(attr, sym::ffi_pure) {
2715 if tcx.is_foreign_item(id) {
2716 if attrs.iter().any(|a| tcx.sess.check_name(a, sym::ffi_const)) {
2717 // `#[ffi_const]` functions cannot be `#[ffi_pure]`
2722 "`#[ffi_const]` function cannot be `#[ffi_pure]`"
2726 codegen_fn_attrs.flags |= CodegenFnAttrFlags::FFI_PURE;
2729 // `#[ffi_pure]` is only allowed on foreign functions
2734 "`#[ffi_pure]` may only be used on foreign functions"
2738 } else if tcx.sess.check_name(attr, sym::ffi_const) {
2739 if tcx.is_foreign_item(id) {
2740 codegen_fn_attrs.flags |= CodegenFnAttrFlags::FFI_CONST;
2742 // `#[ffi_const]` is only allowed on foreign functions
2747 "`#[ffi_const]` may only be used on foreign functions"
2751 } else if tcx.sess.check_name(attr, sym::rustc_allocator_nounwind) {
2752 codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_ALLOCATOR_NOUNWIND;
2753 } else if tcx.sess.check_name(attr, sym::naked) {
2754 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NAKED;
2755 } else if tcx.sess.check_name(attr, sym::no_mangle) {
2756 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_MANGLE;
2757 } else if tcx.sess.check_name(attr, sym::no_coverage) {
2758 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_COVERAGE;
2759 } else if tcx.sess.check_name(attr, sym::rustc_std_internal_symbol) {
2760 codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL;
2761 } else if tcx.sess.check_name(attr, sym::used) {
2762 codegen_fn_attrs.flags |= CodegenFnAttrFlags::USED;
2763 } else if tcx.sess.check_name(attr, sym::cmse_nonsecure_entry) {
2764 if !matches!(tcx.fn_sig(id).abi(), abi::Abi::C { .. }) {
2769 "`#[cmse_nonsecure_entry]` requires C ABI"
2773 if !tcx.sess.target.llvm_target.contains("thumbv8m") {
2774 struct_span_err!(tcx.sess, attr.span, E0775, "`#[cmse_nonsecure_entry]` is only valid for targets with the TrustZone-M extension")
2777 codegen_fn_attrs.flags |= CodegenFnAttrFlags::CMSE_NONSECURE_ENTRY;
2778 } else if tcx.sess.check_name(attr, sym::thread_local) {
2779 codegen_fn_attrs.flags |= CodegenFnAttrFlags::THREAD_LOCAL;
2780 } else if tcx.sess.check_name(attr, sym::track_caller) {
2781 if tcx.is_closure(id) || tcx.fn_sig(id).abi() != abi::Abi::Rust {
2782 struct_span_err!(tcx.sess, attr.span, E0737, "`#[track_caller]` requires Rust ABI")
2785 codegen_fn_attrs.flags |= CodegenFnAttrFlags::TRACK_CALLER;
2786 } else if tcx.sess.check_name(attr, sym::export_name) {
2787 if let Some(s) = attr.value_str() {
2788 if s.as_str().contains('\0') {
2789 // `#[export_name = ...]` will be converted to a null-terminated string,
2790 // so it may not contain any null characters.
2795 "`export_name` may not contain null characters"
2799 codegen_fn_attrs.export_name = Some(s);
2801 } else if tcx.sess.check_name(attr, sym::target_feature) {
2802 if !tcx.is_closure(id) && tcx.fn_sig(id).unsafety() == hir::Unsafety::Normal {
2803 if tcx.sess.target.is_like_wasm || tcx.sess.opts.actually_rustdoc {
2804 // The `#[target_feature]` attribute is allowed on
2805 // WebAssembly targets on all functions, including safe
2806 // ones. Other targets require that `#[target_feature]` is
2807 // only applied to unsafe funtions (pending the
2808 // `target_feature_11` feature) because on most targets
2809 // execution of instructions that are not supported is
2810 // considered undefined behavior. For WebAssembly which is a
2811 // 100% safe target at execution time it's not possible to
2812 // execute undefined instructions, and even if a future
2813 // feature was added in some form for this it would be a
2814 // deterministic trap. There is no undefined behavior when
2815 // executing WebAssembly so `#[target_feature]` is allowed
2816 // on safe functions (but again, only for WebAssembly)
2818 // Note that this is also allowed if `actually_rustdoc` so
2819 // if a target is documenting some wasm-specific code then
2820 // it's not spuriously denied.
2821 } else if !tcx.features().target_feature_11 {
2822 let mut err = feature_err(
2823 &tcx.sess.parse_sess,
2824 sym::target_feature_11,
2826 "`#[target_feature(..)]` can only be applied to `unsafe` functions",
2828 err.span_label(tcx.def_span(id), "not an `unsafe` function");
2830 } else if let Some(local_id) = id.as_local() {
2831 check_target_feature_trait_unsafe(tcx, local_id, attr.span);
2834 from_target_feature(
2838 &supported_target_features,
2839 &mut codegen_fn_attrs.target_features,
2841 } else if tcx.sess.check_name(attr, sym::linkage) {
2842 if let Some(val) = attr.value_str() {
2843 codegen_fn_attrs.linkage = Some(linkage_by_name(tcx, id, &val.as_str()));
2845 } else if tcx.sess.check_name(attr, sym::link_section) {
2846 if let Some(val) = attr.value_str() {
2847 if val.as_str().bytes().any(|b| b == 0) {
2849 "illegal null byte in link_section \
2853 tcx.sess.span_err(attr.span, &msg);
2855 codegen_fn_attrs.link_section = Some(val);
2858 } else if tcx.sess.check_name(attr, sym::link_name) {
2859 codegen_fn_attrs.link_name = attr.value_str();
2860 } else if tcx.sess.check_name(attr, sym::link_ordinal) {
2861 link_ordinal_span = Some(attr.span);
2862 if let ordinal @ Some(_) = check_link_ordinal(tcx, attr) {
2863 codegen_fn_attrs.link_ordinal = ordinal;
2865 } else if tcx.sess.check_name(attr, sym::no_sanitize) {
2866 no_sanitize_span = Some(attr.span);
2867 if let Some(list) = attr.meta_item_list() {
2868 for item in list.iter() {
2869 if item.has_name(sym::address) {
2870 codegen_fn_attrs.no_sanitize |= SanitizerSet::ADDRESS;
2871 } else if item.has_name(sym::memory) {
2872 codegen_fn_attrs.no_sanitize |= SanitizerSet::MEMORY;
2873 } else if item.has_name(sym::thread) {
2874 codegen_fn_attrs.no_sanitize |= SanitizerSet::THREAD;
2875 } else if item.has_name(sym::hwaddress) {
2876 codegen_fn_attrs.no_sanitize |= SanitizerSet::HWADDRESS;
2879 .struct_span_err(item.span(), "invalid argument for `no_sanitize`")
2880 .note("expected one of: `address`, `hwaddress`, `memory` or `thread`")
2885 } else if tcx.sess.check_name(attr, sym::instruction_set) {
2886 codegen_fn_attrs.instruction_set = match attr.meta().map(|i| i.kind) {
2887 Some(MetaItemKind::List(ref items)) => match items.as_slice() {
2888 [NestedMetaItem::MetaItem(set)] => {
2890 set.path.segments.iter().map(|x| x.ident.name).collect::<Vec<_>>();
2891 match segments.as_slice() {
2892 [sym::arm, sym::a32] | [sym::arm, sym::t32] => {
2893 if !tcx.sess.target.has_thumb_interworking {
2895 tcx.sess.diagnostic(),
2898 "target does not support `#[instruction_set]`"
2902 } else if segments[1] == sym::a32 {
2903 Some(InstructionSetAttr::ArmA32)
2904 } else if segments[1] == sym::t32 {
2905 Some(InstructionSetAttr::ArmT32)
2912 tcx.sess.diagnostic(),
2915 "invalid instruction set specified",
2924 tcx.sess.diagnostic(),
2927 "`#[instruction_set]` requires an argument"
2934 tcx.sess.diagnostic(),
2937 "cannot specify more than one instruction set"
2945 tcx.sess.diagnostic(),
2948 "must specify an instruction set"
2954 } else if tcx.sess.check_name(attr, sym::repr) {
2955 codegen_fn_attrs.alignment = match attr.meta_item_list() {
2956 Some(items) => match items.as_slice() {
2957 [item] => match item.name_value_literal() {
2958 Some((sym::align, literal)) => {
2959 let alignment = rustc_attr::parse_alignment(&literal.kind);
2962 Ok(align) => Some(align),
2965 tcx.sess.diagnostic(),
2968 "invalid `repr(align)` attribute: {}",
2987 codegen_fn_attrs.inline = attrs.iter().fold(InlineAttr::None, |ia, attr| {
2988 if !attr.has_name(sym::inline) {
2991 match attr.meta().map(|i| i.kind) {
2992 Some(MetaItemKind::Word) => {
2993 tcx.sess.mark_attr_used(attr);
2996 Some(MetaItemKind::List(ref items)) => {
2997 tcx.sess.mark_attr_used(attr);
2998 inline_span = Some(attr.span);
2999 if items.len() != 1 {
3001 tcx.sess.diagnostic(),
3004 "expected one argument"
3008 } else if list_contains_name(&items[..], sym::always) {
3010 } else if list_contains_name(&items[..], sym::never) {
3014 tcx.sess.diagnostic(),
3024 Some(MetaItemKind::NameValue(_)) => ia,
3029 codegen_fn_attrs.optimize = attrs.iter().fold(OptimizeAttr::None, |ia, attr| {
3030 if !attr.has_name(sym::optimize) {
3033 let err = |sp, s| struct_span_err!(tcx.sess.diagnostic(), sp, E0722, "{}", s).emit();
3034 match attr.meta().map(|i| i.kind) {
3035 Some(MetaItemKind::Word) => {
3036 err(attr.span, "expected one argument");
3039 Some(MetaItemKind::List(ref items)) => {
3040 tcx.sess.mark_attr_used(attr);
3041 inline_span = Some(attr.span);
3042 if items.len() != 1 {
3043 err(attr.span, "expected one argument");
3045 } else if list_contains_name(&items[..], sym::size) {
3047 } else if list_contains_name(&items[..], sym::speed) {
3050 err(items[0].span(), "invalid argument");
3054 Some(MetaItemKind::NameValue(_)) => ia,
3059 // #73631: closures inherit `#[target_feature]` annotations
3060 if tcx.features().target_feature_11 && tcx.is_closure(id) {
3061 let owner_id = tcx.parent(id).expect("closure should have a parent");
3064 .extend(tcx.codegen_fn_attrs(owner_id).target_features.iter().copied())
3067 // If a function uses #[target_feature] it can't be inlined into general
3068 // purpose functions as they wouldn't have the right target features
3069 // enabled. For that reason we also forbid #[inline(always)] as it can't be
3071 if !codegen_fn_attrs.target_features.is_empty() {
3072 if codegen_fn_attrs.inline == InlineAttr::Always {
3073 if let Some(span) = inline_span {
3076 "cannot use `#[inline(always)]` with \
3077 `#[target_feature]`",
3083 if !codegen_fn_attrs.no_sanitize.is_empty() {
3084 if codegen_fn_attrs.inline == InlineAttr::Always {
3085 if let (Some(no_sanitize_span), Some(inline_span)) = (no_sanitize_span, inline_span) {
3086 let hir_id = tcx.hir().local_def_id_to_hir_id(id.expect_local());
3087 tcx.struct_span_lint_hir(
3088 lint::builtin::INLINE_NO_SANITIZE,
3092 lint.build("`no_sanitize` will have no effect after inlining")
3093 .span_note(inline_span, "inlining requested here")
3101 // Weak lang items have the same semantics as "std internal" symbols in the
3102 // sense that they're preserved through all our LTO passes and only
3103 // strippable by the linker.
3105 // Additionally weak lang items have predetermined symbol names.
3106 if tcx.is_weak_lang_item(id) {
3107 codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL;
3109 let check_name = |attr, sym| tcx.sess.check_name(attr, sym);
3110 if let Some(name) = weak_lang_items::link_name(check_name, &attrs) {
3111 codegen_fn_attrs.export_name = Some(name);
3112 codegen_fn_attrs.link_name = Some(name);
3114 check_link_name_xor_ordinal(tcx, &codegen_fn_attrs, link_ordinal_span);
3116 // Internal symbols to the standard library all have no_mangle semantics in
3117 // that they have defined symbol names present in the function name. This
3118 // also applies to weak symbols where they all have known symbol names.
3119 if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL) {
3120 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_MANGLE;
3126 /// Checks if the provided DefId is a method in a trait impl for a trait which has track_caller
3127 /// applied to the method prototype.
3128 fn should_inherit_track_caller(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
3129 if let Some(impl_item) = tcx.opt_associated_item(def_id) {
3130 if let ty::AssocItemContainer::ImplContainer(impl_def_id) = impl_item.container {
3131 if let Some(trait_def_id) = tcx.trait_id_of_impl(impl_def_id) {
3132 if let Some(trait_item) = tcx
3133 .associated_items(trait_def_id)
3134 .filter_by_name_unhygienic(impl_item.ident.name)
3135 .find(move |trait_item| {
3136 trait_item.kind == ty::AssocKind::Fn
3137 && tcx.hygienic_eq(impl_item.ident, trait_item.ident, trait_def_id)
3141 .codegen_fn_attrs(trait_item.def_id)
3143 .intersects(CodegenFnAttrFlags::TRACK_CALLER);
3152 fn check_link_ordinal(tcx: TyCtxt<'_>, attr: &ast::Attribute) -> Option<usize> {
3153 use rustc_ast::{Lit, LitIntType, LitKind};
3154 let meta_item_list = attr.meta_item_list();
3155 let meta_item_list: Option<&[ast::NestedMetaItem]> = meta_item_list.as_ref().map(Vec::as_ref);
3156 let sole_meta_list = match meta_item_list {
3157 Some([item]) => item.literal(),
3160 if let Some(Lit { kind: LitKind::Int(ordinal, LitIntType::Unsuffixed), .. }) = sole_meta_list {
3161 if *ordinal <= usize::MAX as u128 {
3162 Some(*ordinal as usize)
3164 let msg = format!("ordinal value in `link_ordinal` is too large: `{}`", &ordinal);
3166 .struct_span_err(attr.span, &msg)
3167 .note("the value may not exceed `usize::MAX`")
3173 .struct_span_err(attr.span, "illegal ordinal format in `link_ordinal`")
3174 .note("an unsuffixed integer value, e.g., `1`, is expected")
3180 fn check_link_name_xor_ordinal(
3182 codegen_fn_attrs: &CodegenFnAttrs,
3183 inline_span: Option<Span>,
3185 if codegen_fn_attrs.link_name.is_none() || codegen_fn_attrs.link_ordinal.is_none() {
3188 let msg = "cannot use `#[link_name]` with `#[link_ordinal]`";
3189 if let Some(span) = inline_span {
3190 tcx.sess.span_err(span, msg);
3196 /// Checks the function annotated with `#[target_feature]` is not a safe
3197 /// trait method implementation, reporting an error if it is.
3198 fn check_target_feature_trait_unsafe(tcx: TyCtxt<'_>, id: LocalDefId, attr_span: Span) {
3199 let hir_id = tcx.hir().local_def_id_to_hir_id(id);
3200 let node = tcx.hir().get(hir_id);
3201 if let Node::ImplItem(hir::ImplItem { kind: hir::ImplItemKind::Fn(..), .. }) = node {
3202 let parent_id = tcx.hir().get_parent_item(hir_id);
3203 let parent_item = tcx.hir().expect_item(parent_id);
3204 if let hir::ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }) = parent_item.kind {
3208 "`#[target_feature(..)]` cannot be applied to safe trait method",
3210 .span_label(attr_span, "cannot be applied to safe trait method")
3211 .span_label(tcx.def_span(id), "not an `unsafe` function")