1 // ignore-tidy-filelength
3 //! "Collection" is the process of determining the type and other external
4 //! details of each item in Rust. Collection is specifically concerned
5 //! with *inter-procedural* things -- for example, for a function
6 //! definition, collection will figure out the type and signature of the
7 //! function, but it will not visit the *body* of the function in any way,
8 //! nor examine type annotations on local variables (that's the job of
11 //! Collecting is ultimately defined by a bundle of queries that
12 //! inquire after various facts about the items in the crate (e.g.,
13 //! `type_of`, `generics_of`, `predicates_of`, etc). See the `provide` function
16 //! At present, however, we do run collection across all items in the
17 //! crate as a kind of pass. This should eventually be factored away.
19 use crate::astconv::{AstConv, Bounds, SizedByDefault};
20 use crate::check::intrinsic::intrinsic_operation_unsafety;
21 use crate::constrained_generic_params as cgp;
23 use crate::middle::lang_items;
24 use crate::middle::resolve_lifetime as rl;
25 use rustc::hir::map::blocks::FnLikeNode;
26 use rustc::hir::map::Map;
27 use rustc::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs};
28 use rustc::mir::mono::Linkage;
29 use rustc::session::parse::feature_err;
31 use rustc::ty::query::Providers;
32 use rustc::ty::subst::GenericArgKind;
33 use rustc::ty::subst::{InternalSubsts, Subst};
34 use rustc::ty::util::Discr;
35 use rustc::ty::util::IntTypeExt;
36 use rustc::ty::{self, AdtKind, Const, DefIdTree, ToPolyTraitRef, Ty, TyCtxt, WithConstness};
37 use rustc::ty::{ReprOptions, ToPredicate};
38 use rustc_attr::{list_contains_name, mark_used, InlineAttr, OptimizeAttr};
39 use rustc_data_structures::captures::Captures;
40 use rustc_data_structures::fx::FxHashMap;
41 use rustc_errors::{struct_span_err, Applicability, StashKey};
43 use rustc_hir::def::{CtorKind, DefKind, Res};
44 use rustc_hir::def_id::{DefId, LOCAL_CRATE};
45 use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
46 use rustc_hir::{GenericParamKind, Node, Unsafety};
47 use rustc_span::symbol::{kw, sym, Symbol};
48 use rustc_span::{Span, DUMMY_SP};
49 use rustc_target::spec::abi;
51 use syntax::ast::{Ident, MetaItemKind};
53 struct OnlySelfBounds(bool);
55 ///////////////////////////////////////////////////////////////////////////
58 fn collect_mod_item_types(tcx: TyCtxt<'_>, module_def_id: DefId) {
59 tcx.hir().visit_item_likes_in_module(
61 &mut CollectItemTypesVisitor { tcx }.as_deep_visitor(),
65 pub fn provide(providers: &mut Providers<'_>) {
66 *providers = Providers {
70 predicates_defined_on,
71 explicit_predicates_of,
73 type_param_predicates,
82 collect_mod_item_types,
87 ///////////////////////////////////////////////////////////////////////////
89 /// Context specific to some particular item. This is what implements
90 /// `AstConv`. It has information about the predicates that are defined
91 /// on the trait. Unfortunately, this predicate information is
92 /// available in various different forms at various points in the
93 /// process. So we can't just store a pointer to e.g., the AST or the
94 /// parsed ty form, we have to be more flexible. To this end, the
95 /// `ItemCtxt` is parameterized by a `DefId` that it uses to satisfy
96 /// `get_type_parameter_bounds` requests, drawing the information from
97 /// the AST (`hir::Generics`), recursively.
98 pub struct ItemCtxt<'tcx> {
103 ///////////////////////////////////////////////////////////////////////////
106 crate struct PlaceholderHirTyCollector(crate Vec<Span>);
108 impl<'v> Visitor<'v> for PlaceholderHirTyCollector {
111 fn nested_visit_map(&mut self) -> NestedVisitorMap<'_, Self::Map> {
112 NestedVisitorMap::None
114 fn visit_ty(&mut self, t: &'v hir::Ty<'v>) {
115 if let hir::TyKind::Infer = t.kind {
118 intravisit::walk_ty(self, t)
122 struct CollectItemTypesVisitor<'tcx> {
126 /// If there are any placeholder types (`_`), emit an error explaining that this is not allowed
127 /// and suggest adding type parameters in the appropriate place, taking into consideration any and
128 /// all already existing generic type parameters to avoid suggesting a name that is already in use.
129 crate fn placeholder_type_error(
132 generics: &[hir::GenericParam<'_>],
133 placeholder_types: Vec<Span>,
136 if placeholder_types.is_empty() {
139 // This is the whitelist of possible parameter names that we might suggest.
140 let possible_names = ["T", "K", "L", "A", "B", "C"];
141 let used_names = generics
143 .filter_map(|p| match p.name {
144 hir::ParamName::Plain(ident) => Some(ident.name),
147 .collect::<Vec<_>>();
149 let type_name = possible_names
151 .find(|n| !used_names.contains(&Symbol::intern(n)))
152 .unwrap_or(&"ParamName");
154 let mut sugg: Vec<_> =
155 placeholder_types.iter().map(|sp| (*sp, type_name.to_string())).collect();
156 if generics.is_empty() {
157 sugg.push((span, format!("<{}>", type_name)));
158 } else if let Some(arg) = generics.iter().find(|arg| match arg.name {
159 hir::ParamName::Plain(Ident { name: kw::Underscore, .. }) => true,
162 // Account for `_` already present in cases like `struct S<_>(_);` and suggest
163 // `struct S<T>(T);` instead of `struct S<_, T>(T);`.
164 sugg.push((arg.span, format!("{}", type_name)));
167 generics.iter().last().unwrap().span.shrink_to_hi(),
168 format!(", {}", type_name),
171 let mut err = bad_placeholder_type(tcx, placeholder_types);
173 err.multipart_suggestion(
174 "use type parameters instead",
176 Applicability::HasPlaceholders,
182 fn reject_placeholder_type_signatures_in_item(tcx: TyCtxt<'tcx>, item: &'tcx hir::Item<'tcx>) {
183 let (generics, suggest) = match &item.kind {
184 hir::ItemKind::Union(_, generics)
185 | hir::ItemKind::Enum(_, generics)
186 | hir::ItemKind::TraitAlias(generics, _)
187 | hir::ItemKind::Trait(_, _, generics, ..)
188 | hir::ItemKind::Impl { generics, .. }
189 | hir::ItemKind::Struct(_, generics) => (generics, true),
190 hir::ItemKind::OpaqueTy(hir::OpaqueTy { generics, .. })
191 | hir::ItemKind::TyAlias(_, generics) => (generics, false),
192 // `static`, `fn` and `const` are handled elsewhere to suggest appropriate type.
196 let mut visitor = PlaceholderHirTyCollector::default();
197 visitor.visit_item(item);
199 placeholder_type_error(tcx, generics.span, &generics.params[..], visitor.0, suggest);
202 impl Visitor<'tcx> for CollectItemTypesVisitor<'tcx> {
203 type Map = Map<'tcx>;
205 fn nested_visit_map(&mut self) -> NestedVisitorMap<'_, Self::Map> {
206 NestedVisitorMap::OnlyBodies(&self.tcx.hir())
209 fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) {
210 convert_item(self.tcx, item.hir_id);
211 reject_placeholder_type_signatures_in_item(self.tcx, item);
212 intravisit::walk_item(self, item);
215 fn visit_generics(&mut self, generics: &'tcx hir::Generics<'tcx>) {
216 for param in generics.params {
218 hir::GenericParamKind::Lifetime { .. } => {}
219 hir::GenericParamKind::Type { default: Some(_), .. } => {
220 let def_id = self.tcx.hir().local_def_id(param.hir_id);
221 self.tcx.type_of(def_id);
223 hir::GenericParamKind::Type { .. } => {}
224 hir::GenericParamKind::Const { .. } => {
225 let def_id = self.tcx.hir().local_def_id(param.hir_id);
226 self.tcx.type_of(def_id);
230 intravisit::walk_generics(self, generics);
233 fn visit_expr(&mut self, expr: &'tcx hir::Expr<'tcx>) {
234 if let hir::ExprKind::Closure(..) = expr.kind {
235 let def_id = self.tcx.hir().local_def_id(expr.hir_id);
236 self.tcx.generics_of(def_id);
237 self.tcx.type_of(def_id);
239 intravisit::walk_expr(self, expr);
242 fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem<'tcx>) {
243 convert_trait_item(self.tcx, trait_item.hir_id);
244 intravisit::walk_trait_item(self, trait_item);
247 fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem<'tcx>) {
248 convert_impl_item(self.tcx, impl_item.hir_id);
249 intravisit::walk_impl_item(self, impl_item);
253 ///////////////////////////////////////////////////////////////////////////
254 // Utility types and common code for the above passes.
256 fn bad_placeholder_type(
258 mut spans: Vec<Span>,
259 ) -> rustc_errors::DiagnosticBuilder<'tcx> {
261 let mut err = struct_span_err!(
265 "the type placeholder `_` is not allowed within types on item signatures",
268 err.span_label(span, "not allowed in type signatures");
273 impl ItemCtxt<'tcx> {
274 pub fn new(tcx: TyCtxt<'tcx>, item_def_id: DefId) -> ItemCtxt<'tcx> {
275 ItemCtxt { tcx, item_def_id }
278 pub fn to_ty(&self, ast_ty: &'tcx hir::Ty<'tcx>) -> Ty<'tcx> {
279 AstConv::ast_ty_to_ty(self, ast_ty)
282 pub fn hir_id(&self) -> hir::HirId {
285 .as_local_hir_id(self.item_def_id)
286 .expect("Non-local call to local provider is_const_fn")
289 pub fn node(&self) -> hir::Node<'tcx> {
290 self.tcx.hir().get(self.hir_id())
294 impl AstConv<'tcx> for ItemCtxt<'tcx> {
295 fn tcx(&self) -> TyCtxt<'tcx> {
299 fn item_def_id(&self) -> Option<DefId> {
300 Some(self.item_def_id)
303 fn default_constness_for_trait_bounds(&self) -> hir::Constness {
304 if let Some(fn_like) = FnLikeNode::from_node(self.node()) {
307 hir::Constness::NotConst
311 fn get_type_parameter_bounds(&self, span: Span, def_id: DefId) -> ty::GenericPredicates<'tcx> {
312 self.tcx.at(span).type_param_predicates((self.item_def_id, def_id))
315 fn re_infer(&self, _: Option<&ty::GenericParamDef>, _: Span) -> Option<ty::Region<'tcx>> {
319 fn allow_ty_infer(&self) -> bool {
323 fn ty_infer(&self, _: Option<&ty::GenericParamDef>, span: Span) -> Ty<'tcx> {
324 self.tcx().sess.delay_span_bug(span, "bad placeholder type");
331 _: Option<&ty::GenericParamDef>,
333 ) -> &'tcx Const<'tcx> {
334 bad_placeholder_type(self.tcx(), vec![span]).emit();
336 self.tcx().consts.err
339 fn projected_ty_from_poly_trait_ref(
343 item_segment: &hir::PathSegment<'_>,
344 poly_trait_ref: ty::PolyTraitRef<'tcx>,
346 if let Some(trait_ref) = poly_trait_ref.no_bound_vars() {
347 let item_substs = <dyn AstConv<'tcx>>::create_substs_for_associated_item(
355 self.tcx().mk_projection(item_def_id, item_substs)
357 // There are no late-bound regions; we can just ignore the binder.
358 let mut err = struct_span_err!(
362 "cannot extract an associated type from a higher-ranked trait bound \
367 hir::Node::Field(_) | hir::Node::Ctor(_) | hir::Node::Variant(_) => {
369 self.tcx.hir().expect_item(self.tcx.hir().get_parent_item(self.hir_id()));
371 hir::ItemKind::Enum(_, generics)
372 | hir::ItemKind::Struct(_, generics)
373 | hir::ItemKind::Union(_, generics) => {
374 // FIXME: look for an appropriate lt name if `'a` is already used
375 let (lt_sp, sugg) = match &generics.params[..] {
376 [] => (generics.span, "<'a>".to_string()),
377 [bound, ..] => (bound.span.shrink_to_lo(), "'a, ".to_string()),
379 let suggestions = vec![
385 // Replace the existing lifetimes with a new named lifetime.
387 .replace_late_bound_regions(&poly_trait_ref, |_| {
388 self.tcx.mk_region(ty::ReEarlyBound(
389 ty::EarlyBoundRegion {
392 name: Symbol::intern("'a"),
401 err.multipart_suggestion(
402 "use a fully qualified path with explicit lifetimes",
404 Applicability::MaybeIncorrect,
410 hir::Node::Item(hir::Item { kind: hir::ItemKind::Struct(..), .. })
411 | hir::Node::Item(hir::Item { kind: hir::ItemKind::Enum(..), .. })
412 | hir::Node::Item(hir::Item { kind: hir::ItemKind::Union(..), .. }) => {}
414 | hir::Node::ForeignItem(_)
415 | hir::Node::TraitItem(_)
416 | hir::Node::ImplItem(_) => {
419 "use a fully qualified path with inferred lifetimes",
422 // Erase named lt, we want `<A as B<'_>::C`, not `<A as B<'a>::C`.
423 self.tcx.anonymize_late_bound_regions(&poly_trait_ref).skip_binder(),
426 Applicability::MaybeIncorrect,
436 fn normalize_ty(&self, _span: Span, ty: Ty<'tcx>) -> Ty<'tcx> {
437 // Types in item signatures are not normalized to avoid undue dependencies.
441 fn set_tainted_by_errors(&self) {
442 // There's no obvious place to track this, so just let it go.
445 fn record_ty(&self, _hir_id: hir::HirId, _ty: Ty<'tcx>, _span: Span) {
446 // There's no place to record types from signatures?
450 /// Returns the predicates defined on `item_def_id` of the form
451 /// `X: Foo` where `X` is the type parameter `def_id`.
452 fn type_param_predicates(
454 (item_def_id, def_id): (DefId, DefId),
455 ) -> ty::GenericPredicates<'_> {
458 // In the AST, bounds can derive from two places. Either
459 // written inline like `<T: Foo>` or in a where-clause like
462 let param_id = tcx.hir().as_local_hir_id(def_id).unwrap();
463 let param_owner = tcx.hir().ty_param_owner(param_id);
464 let param_owner_def_id = tcx.hir().local_def_id(param_owner);
465 let generics = tcx.generics_of(param_owner_def_id);
466 let index = generics.param_def_id_to_index[&def_id];
467 let ty = tcx.mk_ty_param(index, tcx.hir().ty_param_name(param_id));
469 // Don't look for bounds where the type parameter isn't in scope.
471 if item_def_id == param_owner_def_id { None } else { tcx.generics_of(item_def_id).parent };
473 let mut result = parent
475 let icx = ItemCtxt::new(tcx, parent);
476 icx.get_type_parameter_bounds(DUMMY_SP, def_id)
478 .unwrap_or_default();
479 let mut extend = None;
481 let item_hir_id = tcx.hir().as_local_hir_id(item_def_id).unwrap();
482 let ast_generics = match tcx.hir().get(item_hir_id) {
483 Node::TraitItem(item) => &item.generics,
485 Node::ImplItem(item) => &item.generics,
487 Node::Item(item) => {
489 ItemKind::Fn(.., ref generics, _)
490 | ItemKind::Impl { ref generics, .. }
491 | ItemKind::TyAlias(_, ref generics)
492 | ItemKind::OpaqueTy(OpaqueTy { ref generics, impl_trait_fn: None, .. })
493 | ItemKind::Enum(_, ref generics)
494 | ItemKind::Struct(_, ref generics)
495 | ItemKind::Union(_, ref generics) => generics,
496 ItemKind::Trait(_, _, ref generics, ..) => {
497 // Implied `Self: Trait` and supertrait bounds.
498 if param_id == item_hir_id {
499 let identity_trait_ref = ty::TraitRef::identity(tcx, item_def_id);
501 Some((identity_trait_ref.without_const().to_predicate(), item.span));
509 Node::ForeignItem(item) => match item.kind {
510 ForeignItemKind::Fn(_, _, ref generics) => generics,
517 let icx = ItemCtxt::new(tcx, item_def_id);
518 let extra_predicates = extend.into_iter().chain(
519 icx.type_parameter_bounds_in_generics(ast_generics, param_id, ty, OnlySelfBounds(true))
521 .filter(|(predicate, _)| match predicate {
522 ty::Predicate::Trait(ref data, _) => data.skip_binder().self_ty().is_param(index),
527 tcx.arena.alloc_from_iter(result.predicates.iter().copied().chain(extra_predicates));
531 impl ItemCtxt<'tcx> {
532 /// Finds bounds from `hir::Generics`. This requires scanning through the
533 /// AST. We do this to avoid having to convert *all* the bounds, which
534 /// would create artificial cycles. Instead, we can only convert the
535 /// bounds for a type parameter `X` if `X::Foo` is used.
536 fn type_parameter_bounds_in_generics(
538 ast_generics: &'tcx hir::Generics<'tcx>,
539 param_id: hir::HirId,
541 only_self_bounds: OnlySelfBounds,
542 ) -> Vec<(ty::Predicate<'tcx>, Span)> {
543 let constness = self.default_constness_for_trait_bounds();
544 let from_ty_params = ast_generics
547 .filter_map(|param| match param.kind {
548 GenericParamKind::Type { .. } if param.hir_id == param_id => Some(¶m.bounds),
551 .flat_map(|bounds| bounds.iter())
552 .flat_map(|b| predicates_from_bound(self, ty, b, constness));
554 let from_where_clauses = ast_generics
558 .filter_map(|wp| match *wp {
559 hir::WherePredicate::BoundPredicate(ref bp) => Some(bp),
563 let bt = if is_param(self.tcx, &bp.bounded_ty, param_id) {
565 } else if !only_self_bounds.0 {
566 Some(self.to_ty(&bp.bounded_ty))
570 bp.bounds.iter().filter_map(move |b| bt.map(|bt| (bt, b)))
572 .flat_map(|(bt, b)| predicates_from_bound(self, bt, b, constness));
574 from_ty_params.chain(from_where_clauses).collect()
578 /// Tests whether this is the AST for a reference to the type
579 /// parameter with ID `param_id`. We use this so as to avoid running
580 /// `ast_ty_to_ty`, because we want to avoid triggering an all-out
581 /// conversion of the type to avoid inducing unnecessary cycles.
582 fn is_param(tcx: TyCtxt<'_>, ast_ty: &hir::Ty<'_>, param_id: hir::HirId) -> bool {
583 if let hir::TyKind::Path(hir::QPath::Resolved(None, ref path)) = ast_ty.kind {
585 Res::SelfTy(Some(def_id), None) | Res::Def(DefKind::TyParam, def_id) => {
586 def_id == tcx.hir().local_def_id(param_id)
595 fn convert_item(tcx: TyCtxt<'_>, item_id: hir::HirId) {
596 let it = tcx.hir().expect_item(item_id);
597 debug!("convert: item {} with id {}", it.ident, it.hir_id);
598 let def_id = tcx.hir().local_def_id(item_id);
600 // These don't define types.
601 hir::ItemKind::ExternCrate(_)
602 | hir::ItemKind::Use(..)
603 | hir::ItemKind::Mod(_)
604 | hir::ItemKind::GlobalAsm(_) => {}
605 hir::ItemKind::ForeignMod(ref foreign_mod) => {
606 for item in foreign_mod.items {
607 let def_id = tcx.hir().local_def_id(item.hir_id);
608 tcx.generics_of(def_id);
610 tcx.predicates_of(def_id);
611 if let hir::ForeignItemKind::Fn(..) = item.kind {
616 hir::ItemKind::Enum(ref enum_definition, _) => {
617 tcx.generics_of(def_id);
619 tcx.predicates_of(def_id);
620 convert_enum_variant_types(tcx, def_id, &enum_definition.variants);
622 hir::ItemKind::Impl { .. } => {
623 tcx.generics_of(def_id);
625 tcx.impl_trait_ref(def_id);
626 tcx.predicates_of(def_id);
628 hir::ItemKind::Trait(..) => {
629 tcx.generics_of(def_id);
630 tcx.trait_def(def_id);
631 tcx.at(it.span).super_predicates_of(def_id);
632 tcx.predicates_of(def_id);
634 hir::ItemKind::TraitAlias(..) => {
635 tcx.generics_of(def_id);
636 tcx.at(it.span).super_predicates_of(def_id);
637 tcx.predicates_of(def_id);
639 hir::ItemKind::Struct(ref struct_def, _) | hir::ItemKind::Union(ref struct_def, _) => {
640 tcx.generics_of(def_id);
642 tcx.predicates_of(def_id);
644 for f in struct_def.fields() {
645 let def_id = tcx.hir().local_def_id(f.hir_id);
646 tcx.generics_of(def_id);
648 tcx.predicates_of(def_id);
651 if let Some(ctor_hir_id) = struct_def.ctor_hir_id() {
652 convert_variant_ctor(tcx, ctor_hir_id);
656 // Desugared from `impl Trait`, so visited by the function's return type.
657 hir::ItemKind::OpaqueTy(hir::OpaqueTy { impl_trait_fn: Some(_), .. }) => {}
659 hir::ItemKind::OpaqueTy(..)
660 | hir::ItemKind::TyAlias(..)
661 | hir::ItemKind::Static(..)
662 | hir::ItemKind::Const(..)
663 | hir::ItemKind::Fn(..) => {
664 tcx.generics_of(def_id);
666 tcx.predicates_of(def_id);
667 if let hir::ItemKind::Fn(..) = it.kind {
674 fn convert_trait_item(tcx: TyCtxt<'_>, trait_item_id: hir::HirId) {
675 let trait_item = tcx.hir().expect_trait_item(trait_item_id);
676 let def_id = tcx.hir().local_def_id(trait_item.hir_id);
677 tcx.generics_of(def_id);
679 match trait_item.kind {
680 hir::TraitItemKind::Const(..)
681 | hir::TraitItemKind::Type(_, Some(_))
682 | hir::TraitItemKind::Method(..) => {
684 if let hir::TraitItemKind::Method(..) = trait_item.kind {
689 hir::TraitItemKind::Type(_, None) => {}
692 tcx.predicates_of(def_id);
695 fn convert_impl_item(tcx: TyCtxt<'_>, impl_item_id: hir::HirId) {
696 let def_id = tcx.hir().local_def_id(impl_item_id);
697 tcx.generics_of(def_id);
699 tcx.predicates_of(def_id);
700 if let hir::ImplItemKind::Method(..) = tcx.hir().expect_impl_item(impl_item_id).kind {
705 fn convert_variant_ctor(tcx: TyCtxt<'_>, ctor_id: hir::HirId) {
706 let def_id = tcx.hir().local_def_id(ctor_id);
707 tcx.generics_of(def_id);
709 tcx.predicates_of(def_id);
712 fn convert_enum_variant_types(tcx: TyCtxt<'_>, def_id: DefId, variants: &[hir::Variant<'_>]) {
713 let def = tcx.adt_def(def_id);
714 let repr_type = def.repr.discr_type();
715 let initial = repr_type.initial_discriminant(tcx);
716 let mut prev_discr = None::<Discr<'_>>;
718 // fill the discriminant values and field types
719 for variant in variants {
720 let wrapped_discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
722 if let Some(ref e) = variant.disr_expr {
723 let expr_did = tcx.hir().local_def_id(e.hir_id);
724 def.eval_explicit_discr(tcx, expr_did)
725 } else if let Some(discr) = repr_type.disr_incr(tcx, prev_discr) {
728 struct_span_err!(tcx.sess, variant.span, E0370, "enum discriminant overflowed")
731 format!("overflowed on value after {}", prev_discr.unwrap()),
734 "explicitly set `{} = {}` if that is desired outcome",
735 variant.ident, wrapped_discr
740 .unwrap_or(wrapped_discr),
743 for f in variant.data.fields() {
744 let def_id = tcx.hir().local_def_id(f.hir_id);
745 tcx.generics_of(def_id);
747 tcx.predicates_of(def_id);
750 // Convert the ctor, if any. This also registers the variant as
752 if let Some(ctor_hir_id) = variant.data.ctor_hir_id() {
753 convert_variant_ctor(tcx, ctor_hir_id);
760 variant_did: Option<DefId>,
761 ctor_did: Option<DefId>,
763 discr: ty::VariantDiscr,
764 def: &hir::VariantData<'_>,
765 adt_kind: ty::AdtKind,
767 ) -> ty::VariantDef {
768 let mut seen_fields: FxHashMap<ast::Ident, Span> = Default::default();
769 let hir_id = tcx.hir().as_local_hir_id(variant_did.unwrap_or(parent_did)).unwrap();
774 let fid = tcx.hir().local_def_id(f.hir_id);
775 let dup_span = seen_fields.get(&f.ident.modern()).cloned();
776 if let Some(prev_span) = dup_span {
781 "field `{}` is already declared",
784 .span_label(f.span, "field already declared")
785 .span_label(prev_span, format!("`{}` first declared here", f.ident))
788 seen_fields.insert(f.ident.modern(), f.span);
794 vis: ty::Visibility::from_hir(&f.vis, hir_id, tcx),
798 let recovered = match def {
799 hir::VariantData::Struct(_, r) => *r,
809 CtorKind::from_hir(def),
816 fn adt_def(tcx: TyCtxt<'_>, def_id: DefId) -> &ty::AdtDef {
819 let hir_id = tcx.hir().as_local_hir_id(def_id).unwrap();
820 let item = match tcx.hir().get(hir_id) {
821 Node::Item(item) => item,
825 let repr = ReprOptions::new(tcx, def_id);
826 let (kind, variants) = match item.kind {
827 ItemKind::Enum(ref def, _) => {
828 let mut distance_from_explicit = 0;
833 let variant_did = Some(tcx.hir().local_def_id(v.id));
835 v.data.ctor_hir_id().map(|hir_id| tcx.hir().local_def_id(hir_id));
837 let discr = if let Some(ref e) = v.disr_expr {
838 distance_from_explicit = 0;
839 ty::VariantDiscr::Explicit(tcx.hir().local_def_id(e.hir_id))
841 ty::VariantDiscr::Relative(distance_from_explicit)
843 distance_from_explicit += 1;
858 (AdtKind::Enum, variants)
860 ItemKind::Struct(ref def, _) => {
861 let variant_did = None;
862 let ctor_did = def.ctor_hir_id().map(|hir_id| tcx.hir().local_def_id(hir_id));
864 let variants = std::iter::once(convert_variant(
869 ty::VariantDiscr::Relative(0),
876 (AdtKind::Struct, variants)
878 ItemKind::Union(ref def, _) => {
879 let variant_did = None;
880 let ctor_did = def.ctor_hir_id().map(|hir_id| tcx.hir().local_def_id(hir_id));
882 let variants = std::iter::once(convert_variant(
887 ty::VariantDiscr::Relative(0),
894 (AdtKind::Union, variants)
898 tcx.alloc_adt_def(def_id, kind, variants, repr)
901 /// Ensures that the super-predicates of the trait with a `DefId`
902 /// of `trait_def_id` are converted and stored. This also ensures that
903 /// the transitive super-predicates are converted.
904 fn super_predicates_of(tcx: TyCtxt<'_>, trait_def_id: DefId) -> ty::GenericPredicates<'_> {
905 debug!("super_predicates(trait_def_id={:?})", trait_def_id);
906 let trait_hir_id = tcx.hir().as_local_hir_id(trait_def_id).unwrap();
908 let item = match tcx.hir().get(trait_hir_id) {
909 Node::Item(item) => item,
910 _ => bug!("trait_node_id {} is not an item", trait_hir_id),
913 let (generics, bounds) = match item.kind {
914 hir::ItemKind::Trait(.., ref generics, ref supertraits, _) => (generics, supertraits),
915 hir::ItemKind::TraitAlias(ref generics, ref supertraits) => (generics, supertraits),
916 _ => span_bug!(item.span, "super_predicates invoked on non-trait"),
919 let icx = ItemCtxt::new(tcx, trait_def_id);
921 // Convert the bounds that follow the colon, e.g., `Bar + Zed` in `trait Foo: Bar + Zed`.
922 let self_param_ty = tcx.types.self_param;
924 AstConv::compute_bounds(&icx, self_param_ty, bounds, SizedByDefault::No, item.span);
926 let superbounds1 = superbounds1.predicates(tcx, self_param_ty);
928 // Convert any explicit superbounds in the where-clause,
929 // e.g., `trait Foo where Self: Bar`.
930 // In the case of trait aliases, however, we include all bounds in the where-clause,
931 // so e.g., `trait Foo = where u32: PartialEq<Self>` would include `u32: PartialEq<Self>`
932 // as one of its "superpredicates".
933 let is_trait_alias = tcx.is_trait_alias(trait_def_id);
934 let superbounds2 = icx.type_parameter_bounds_in_generics(
938 OnlySelfBounds(!is_trait_alias),
941 // Combine the two lists to form the complete set of superbounds:
942 let superbounds = &*tcx.arena.alloc_from_iter(superbounds1.into_iter().chain(superbounds2));
944 // Now require that immediate supertraits are converted,
945 // which will, in turn, reach indirect supertraits.
946 for &(pred, span) in superbounds {
947 debug!("superbound: {:?}", pred);
948 if let ty::Predicate::Trait(bound, _) = pred {
949 tcx.at(span).super_predicates_of(bound.def_id());
953 ty::GenericPredicates { parent: None, predicates: superbounds }
956 fn trait_def(tcx: TyCtxt<'_>, def_id: DefId) -> &ty::TraitDef {
957 let hir_id = tcx.hir().as_local_hir_id(def_id).unwrap();
958 let item = tcx.hir().expect_item(hir_id);
960 let (is_auto, unsafety) = match item.kind {
961 hir::ItemKind::Trait(is_auto, unsafety, ..) => (is_auto == hir::IsAuto::Yes, unsafety),
962 hir::ItemKind::TraitAlias(..) => (false, hir::Unsafety::Normal),
963 _ => span_bug!(item.span, "trait_def_of_item invoked on non-trait"),
966 let paren_sugar = tcx.has_attr(def_id, sym::rustc_paren_sugar);
967 if paren_sugar && !tcx.features().unboxed_closures {
971 "the `#[rustc_paren_sugar]` attribute is a temporary means of controlling \
972 which traits can use parenthetical notation",
974 .help("add `#![feature(unboxed_closures)]` to the crate attributes to use it")
978 let is_marker = tcx.has_attr(def_id, sym::marker);
979 let def_path_hash = tcx.def_path_hash(def_id);
980 let def = ty::TraitDef::new(def_id, unsafety, paren_sugar, is_auto, is_marker, def_path_hash);
984 fn has_late_bound_regions<'tcx>(tcx: TyCtxt<'tcx>, node: Node<'tcx>) -> Option<Span> {
985 struct LateBoundRegionsDetector<'tcx> {
987 outer_index: ty::DebruijnIndex,
988 has_late_bound_regions: Option<Span>,
991 impl Visitor<'tcx> for LateBoundRegionsDetector<'tcx> {
992 type Map = Map<'tcx>;
994 fn nested_visit_map(&mut self) -> NestedVisitorMap<'_, Self::Map> {
995 NestedVisitorMap::None
998 fn visit_ty(&mut self, ty: &'tcx hir::Ty<'tcx>) {
999 if self.has_late_bound_regions.is_some() {
1003 hir::TyKind::BareFn(..) => {
1004 self.outer_index.shift_in(1);
1005 intravisit::walk_ty(self, ty);
1006 self.outer_index.shift_out(1);
1008 _ => intravisit::walk_ty(self, ty),
1012 fn visit_poly_trait_ref(
1014 tr: &'tcx hir::PolyTraitRef<'tcx>,
1015 m: hir::TraitBoundModifier,
1017 if self.has_late_bound_regions.is_some() {
1020 self.outer_index.shift_in(1);
1021 intravisit::walk_poly_trait_ref(self, tr, m);
1022 self.outer_index.shift_out(1);
1025 fn visit_lifetime(&mut self, lt: &'tcx hir::Lifetime) {
1026 if self.has_late_bound_regions.is_some() {
1030 match self.tcx.named_region(lt.hir_id) {
1031 Some(rl::Region::Static) | Some(rl::Region::EarlyBound(..)) => {}
1032 Some(rl::Region::LateBound(debruijn, _, _))
1033 | Some(rl::Region::LateBoundAnon(debruijn, _))
1034 if debruijn < self.outer_index => {}
1035 Some(rl::Region::LateBound(..))
1036 | Some(rl::Region::LateBoundAnon(..))
1037 | Some(rl::Region::Free(..))
1039 self.has_late_bound_regions = Some(lt.span);
1045 fn has_late_bound_regions<'tcx>(
1047 generics: &'tcx hir::Generics<'tcx>,
1048 decl: &'tcx hir::FnDecl<'tcx>,
1050 let mut visitor = LateBoundRegionsDetector {
1052 outer_index: ty::INNERMOST,
1053 has_late_bound_regions: None,
1055 for param in generics.params {
1056 if let GenericParamKind::Lifetime { .. } = param.kind {
1057 if tcx.is_late_bound(param.hir_id) {
1058 return Some(param.span);
1062 visitor.visit_fn_decl(decl);
1063 visitor.has_late_bound_regions
1067 Node::TraitItem(item) => match item.kind {
1068 hir::TraitItemKind::Method(ref sig, _) => {
1069 has_late_bound_regions(tcx, &item.generics, &sig.decl)
1073 Node::ImplItem(item) => match item.kind {
1074 hir::ImplItemKind::Method(ref sig, _) => {
1075 has_late_bound_regions(tcx, &item.generics, &sig.decl)
1079 Node::ForeignItem(item) => match item.kind {
1080 hir::ForeignItemKind::Fn(ref fn_decl, _, ref generics) => {
1081 has_late_bound_regions(tcx, generics, fn_decl)
1085 Node::Item(item) => match item.kind {
1086 hir::ItemKind::Fn(ref sig, .., ref generics, _) => {
1087 has_late_bound_regions(tcx, generics, &sig.decl)
1095 fn generics_of(tcx: TyCtxt<'_>, def_id: DefId) -> &ty::Generics {
1098 let hir_id = tcx.hir().as_local_hir_id(def_id).unwrap();
1100 let node = tcx.hir().get(hir_id);
1101 let parent_def_id = match node {
1103 | Node::TraitItem(_)
1106 | Node::Field(_) => {
1107 let parent_id = tcx.hir().get_parent_item(hir_id);
1108 Some(tcx.hir().local_def_id(parent_id))
1110 // FIXME(#43408) enable this always when we get lazy normalization.
1111 Node::AnonConst(_) => {
1112 // HACK(eddyb) this provides the correct generics when
1113 // `feature(const_generics)` is enabled, so that const expressions
1114 // used with const generics, e.g. `Foo<{N+1}>`, can work at all.
1115 if tcx.features().const_generics {
1116 let parent_id = tcx.hir().get_parent_item(hir_id);
1117 Some(tcx.hir().local_def_id(parent_id))
1122 Node::Expr(&hir::Expr { kind: hir::ExprKind::Closure(..), .. }) => {
1123 Some(tcx.closure_base_def_id(def_id))
1125 Node::Item(item) => match item.kind {
1126 ItemKind::OpaqueTy(hir::OpaqueTy { impl_trait_fn, .. }) => {
1127 impl_trait_fn.or_else(|| {
1128 let parent_id = tcx.hir().get_parent_item(hir_id);
1129 if parent_id != hir_id && parent_id != CRATE_HIR_ID {
1130 debug!("generics_of: parent of opaque ty {:?} is {:?}", def_id, parent_id);
1131 // If this 'impl Trait' is nested inside another 'impl Trait'
1132 // (e.g. `impl Foo<MyType = impl Bar<A>>`), we need to use the 'parent'
1133 // 'impl Trait' for its generic parameters, since we can reference them
1134 // from the 'child' 'impl Trait'
1135 if let Node::Item(hir::Item { kind: ItemKind::OpaqueTy(..), .. }) =
1136 tcx.hir().get(parent_id)
1138 Some(tcx.hir().local_def_id(parent_id))
1152 let mut opt_self = None;
1153 let mut allow_defaults = false;
1155 let no_generics = hir::Generics::empty();
1156 let ast_generics = match node {
1157 Node::TraitItem(item) => &item.generics,
1159 Node::ImplItem(item) => &item.generics,
1161 Node::Item(item) => {
1163 ItemKind::Fn(.., ref generics, _) | ItemKind::Impl { ref generics, .. } => generics,
1165 ItemKind::TyAlias(_, ref generics)
1166 | ItemKind::Enum(_, ref generics)
1167 | ItemKind::Struct(_, ref generics)
1168 | ItemKind::OpaqueTy(hir::OpaqueTy { ref generics, .. })
1169 | ItemKind::Union(_, ref generics) => {
1170 allow_defaults = true;
1174 ItemKind::Trait(_, _, ref generics, ..)
1175 | ItemKind::TraitAlias(ref generics, ..) => {
1176 // Add in the self type parameter.
1178 // Something of a hack: use the node id for the trait, also as
1179 // the node id for the Self type parameter.
1180 let param_id = item.hir_id;
1182 opt_self = Some(ty::GenericParamDef {
1184 name: kw::SelfUpper,
1185 def_id: tcx.hir().local_def_id(param_id),
1186 pure_wrt_drop: false,
1187 kind: ty::GenericParamDefKind::Type {
1189 object_lifetime_default: rl::Set1::Empty,
1194 allow_defaults = true;
1202 Node::ForeignItem(item) => match item.kind {
1203 ForeignItemKind::Static(..) => &no_generics,
1204 ForeignItemKind::Fn(_, _, ref generics) => generics,
1205 ForeignItemKind::Type => &no_generics,
1211 let has_self = opt_self.is_some();
1212 let mut parent_has_self = false;
1213 let mut own_start = has_self as u32;
1214 let parent_count = parent_def_id.map_or(0, |def_id| {
1215 let generics = tcx.generics_of(def_id);
1216 assert_eq!(has_self, false);
1217 parent_has_self = generics.has_self;
1218 own_start = generics.count() as u32;
1219 generics.parent_count + generics.params.len()
1222 let mut params: Vec<_> = opt_self.into_iter().collect();
1224 let early_lifetimes = early_bound_lifetimes_from_generics(tcx, ast_generics);
1225 params.extend(early_lifetimes.enumerate().map(|(i, param)| ty::GenericParamDef {
1226 name: param.name.ident().name,
1227 index: own_start + i as u32,
1228 def_id: tcx.hir().local_def_id(param.hir_id),
1229 pure_wrt_drop: param.pure_wrt_drop,
1230 kind: ty::GenericParamDefKind::Lifetime,
1233 let object_lifetime_defaults = tcx.object_lifetime_defaults(hir_id);
1235 // Now create the real type parameters.
1236 let type_start = own_start - has_self as u32 + params.len() as u32;
1238 params.extend(ast_generics.params.iter().filter_map(|param| {
1239 let kind = match param.kind {
1240 GenericParamKind::Type { ref default, synthetic, .. } => {
1241 if !allow_defaults && default.is_some() {
1242 if !tcx.features().default_type_parameter_fallback {
1243 tcx.struct_span_lint_hir(
1244 lint::builtin::INVALID_TYPE_PARAM_DEFAULT,
1248 lint.build(&format!(
1249 "defaults for type parameters are only allowed in \
1250 `struct`, `enum`, `type`, or `trait` definitions."
1258 ty::GenericParamDefKind::Type {
1259 has_default: default.is_some(),
1260 object_lifetime_default: object_lifetime_defaults
1262 .map_or(rl::Set1::Empty, |o| o[i]),
1266 GenericParamKind::Const { .. } => ty::GenericParamDefKind::Const,
1270 let param_def = ty::GenericParamDef {
1271 index: type_start + i as u32,
1272 name: param.name.ident().name,
1273 def_id: tcx.hir().local_def_id(param.hir_id),
1274 pure_wrt_drop: param.pure_wrt_drop,
1281 // provide junk type parameter defs - the only place that
1282 // cares about anything but the length is instantiation,
1283 // and we don't do that for closures.
1284 if let Node::Expr(&hir::Expr { kind: hir::ExprKind::Closure(.., gen), .. }) = node {
1285 let dummy_args = if gen.is_some() {
1286 &["<resume_ty>", "<yield_ty>", "<return_ty>", "<witness>"][..]
1288 &["<closure_kind>", "<closure_signature>"][..]
1291 params.extend(dummy_args.iter().enumerate().map(|(i, &arg)| ty::GenericParamDef {
1292 index: type_start + i as u32,
1293 name: Symbol::intern(arg),
1295 pure_wrt_drop: false,
1296 kind: ty::GenericParamDefKind::Type {
1298 object_lifetime_default: rl::Set1::Empty,
1303 if let Some(upvars) = tcx.upvars(def_id) {
1304 params.extend(upvars.iter().zip((dummy_args.len() as u32)..).map(|(_, i)| {
1305 ty::GenericParamDef {
1306 index: type_start + i,
1307 name: Symbol::intern("<upvar>"),
1309 pure_wrt_drop: false,
1310 kind: ty::GenericParamDefKind::Type {
1312 object_lifetime_default: rl::Set1::Empty,
1320 let param_def_id_to_index = params.iter().map(|param| (param.def_id, param.index)).collect();
1322 tcx.arena.alloc(ty::Generics {
1323 parent: parent_def_id,
1326 param_def_id_to_index,
1327 has_self: has_self || parent_has_self,
1328 has_late_bound_regions: has_late_bound_regions(tcx, node),
1332 fn report_assoc_ty_on_inherent_impl(tcx: TyCtxt<'_>, span: Span) {
1337 "associated types are not yet supported in inherent impls (see #8995)"
1342 fn infer_placeholder_type(
1345 body_id: hir::BodyId,
1349 let ty = tcx.diagnostic_only_typeck_tables_of(def_id).node_type(body_id.hir_id);
1351 // If this came from a free `const` or `static mut?` item,
1352 // then the user may have written e.g. `const A = 42;`.
1353 // In this case, the parser has stashed a diagnostic for
1354 // us to improve in typeck so we do that now.
1355 match tcx.sess.diagnostic().steal_diagnostic(span, StashKey::ItemNoType) {
1357 // The parser provided a sub-optimal `HasPlaceholders` suggestion for the type.
1358 // We are typeck and have the real type, so remove that and suggest the actual type.
1359 err.suggestions.clear();
1360 err.span_suggestion(
1362 "provide a type for the item",
1363 format!("{}: {}", item_ident, ty),
1364 Applicability::MachineApplicable,
1369 let mut diag = bad_placeholder_type(tcx, vec![span]);
1370 if ty != tcx.types.err {
1371 diag.span_suggestion(
1373 "replace `_` with the correct type",
1375 Applicability::MaybeIncorrect,
1385 fn type_of(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> {
1388 let hir_id = tcx.hir().as_local_hir_id(def_id).unwrap();
1390 let icx = ItemCtxt::new(tcx, def_id);
1392 match tcx.hir().get(hir_id) {
1393 Node::TraitItem(item) => match item.kind {
1394 TraitItemKind::Method(..) => {
1395 let substs = InternalSubsts::identity_for_item(tcx, def_id);
1396 tcx.mk_fn_def(def_id, substs)
1398 TraitItemKind::Const(ref ty, body_id) => body_id
1399 .and_then(|body_id| {
1400 if is_suggestable_infer_ty(ty) {
1401 Some(infer_placeholder_type(tcx, def_id, body_id, ty.span, item.ident))
1406 .unwrap_or_else(|| icx.to_ty(ty)),
1407 TraitItemKind::Type(_, Some(ref ty)) => icx.to_ty(ty),
1408 TraitItemKind::Type(_, None) => {
1409 span_bug!(item.span, "associated type missing default");
1413 Node::ImplItem(item) => match item.kind {
1414 ImplItemKind::Method(..) => {
1415 let substs = InternalSubsts::identity_for_item(tcx, def_id);
1416 tcx.mk_fn_def(def_id, substs)
1418 ImplItemKind::Const(ref ty, body_id) => {
1419 if is_suggestable_infer_ty(ty) {
1420 infer_placeholder_type(tcx, def_id, body_id, ty.span, item.ident)
1425 ImplItemKind::OpaqueTy(_) => {
1426 if tcx.impl_trait_ref(tcx.hir().get_parent_did(hir_id)).is_none() {
1427 report_assoc_ty_on_inherent_impl(tcx, item.span);
1430 find_opaque_ty_constraints(tcx, def_id)
1432 ImplItemKind::TyAlias(ref ty) => {
1433 if tcx.impl_trait_ref(tcx.hir().get_parent_did(hir_id)).is_none() {
1434 report_assoc_ty_on_inherent_impl(tcx, item.span);
1441 Node::Item(item) => {
1443 ItemKind::Static(ref ty, .., body_id) | ItemKind::Const(ref ty, body_id) => {
1444 if is_suggestable_infer_ty(ty) {
1445 infer_placeholder_type(tcx, def_id, body_id, ty.span, item.ident)
1450 ItemKind::TyAlias(ref self_ty, _) | ItemKind::Impl { ref self_ty, .. } => {
1453 ItemKind::Fn(..) => {
1454 let substs = InternalSubsts::identity_for_item(tcx, def_id);
1455 tcx.mk_fn_def(def_id, substs)
1457 ItemKind::Enum(..) | ItemKind::Struct(..) | ItemKind::Union(..) => {
1458 let def = tcx.adt_def(def_id);
1459 let substs = InternalSubsts::identity_for_item(tcx, def_id);
1460 tcx.mk_adt(def, substs)
1462 ItemKind::OpaqueTy(hir::OpaqueTy { impl_trait_fn: None, .. }) => {
1463 find_opaque_ty_constraints(tcx, def_id)
1465 // Opaque types desugared from `impl Trait`.
1466 ItemKind::OpaqueTy(hir::OpaqueTy { impl_trait_fn: Some(owner), .. }) => {
1467 tcx.mir_borrowck(owner)
1468 .concrete_opaque_types
1470 .map(|opaque| opaque.concrete_type)
1471 .unwrap_or_else(|| {
1472 // This can occur if some error in the
1473 // owner fn prevented us from populating
1474 // the `concrete_opaque_types` table.
1475 tcx.sess.delay_span_bug(
1478 "owner {:?} has no opaque type for {:?} in its tables",
1486 | ItemKind::TraitAlias(..)
1488 | ItemKind::ForeignMod(..)
1489 | ItemKind::GlobalAsm(..)
1490 | ItemKind::ExternCrate(..)
1491 | ItemKind::Use(..) => {
1494 "compute_type_of_item: unexpected item type: {:?}",
1501 Node::ForeignItem(foreign_item) => match foreign_item.kind {
1502 ForeignItemKind::Fn(..) => {
1503 let substs = InternalSubsts::identity_for_item(tcx, def_id);
1504 tcx.mk_fn_def(def_id, substs)
1506 ForeignItemKind::Static(ref t, _) => icx.to_ty(t),
1507 ForeignItemKind::Type => tcx.mk_foreign(def_id),
1510 Node::Ctor(&ref def) | Node::Variant(hir::Variant { data: ref def, .. }) => match *def {
1511 VariantData::Unit(..) | VariantData::Struct(..) => {
1512 tcx.type_of(tcx.hir().get_parent_did(hir_id))
1514 VariantData::Tuple(..) => {
1515 let substs = InternalSubsts::identity_for_item(tcx, def_id);
1516 tcx.mk_fn_def(def_id, substs)
1520 Node::Field(field) => icx.to_ty(&field.ty),
1522 Node::Expr(&hir::Expr { kind: hir::ExprKind::Closure(.., gen), .. }) => {
1524 return tcx.typeck_tables_of(def_id).node_type(hir_id);
1527 let substs = InternalSubsts::identity_for_item(tcx, def_id);
1528 tcx.mk_closure(def_id, substs)
1531 Node::AnonConst(_) => {
1532 let parent_node = tcx.hir().get(tcx.hir().get_parent_node(hir_id));
1534 Node::Ty(&hir::Ty { kind: hir::TyKind::Array(_, ref constant), .. })
1535 | Node::Ty(&hir::Ty { kind: hir::TyKind::Typeof(ref constant), .. })
1536 | Node::Expr(&hir::Expr { kind: ExprKind::Repeat(_, ref constant), .. })
1537 if constant.hir_id == hir_id =>
1542 Node::Variant(Variant { disr_expr: Some(ref e), .. }) if e.hir_id == hir_id => {
1543 tcx.adt_def(tcx.hir().get_parent_did(hir_id)).repr.discr_type().to_ty(tcx)
1546 Node::Ty(&hir::Ty { kind: hir::TyKind::Path(_), .. })
1547 | Node::Expr(&hir::Expr { kind: ExprKind::Struct(..), .. })
1548 | Node::Expr(&hir::Expr { kind: ExprKind::Path(_), .. })
1549 | Node::TraitRef(..) => {
1550 let path = match parent_node {
1552 kind: hir::TyKind::Path(QPath::Resolved(_, ref path)),
1555 | Node::Expr(&hir::Expr {
1556 kind: ExprKind::Path(QPath::Resolved(_, ref path)),
1558 }) => Some(&**path),
1559 Node::Expr(&hir::Expr { kind: ExprKind::Struct(ref path, ..), .. }) => {
1560 if let QPath::Resolved(_, ref path) = **path {
1566 Node::TraitRef(&hir::TraitRef { ref path, .. }) => Some(&**path),
1570 if let Some(path) = path {
1571 let arg_index = path
1574 .filter_map(|seg| seg.args.as_ref())
1575 .map(|generic_args| generic_args.args.as_ref())
1578 .filter(|arg| arg.is_const())
1580 .filter(|(_, arg)| arg.id() == hir_id)
1581 .map(|(index, _)| index)
1584 .unwrap_or_else(|| {
1585 bug!("no arg matching AnonConst in path");
1588 // We've encountered an `AnonConst` in some path, so we need to
1589 // figure out which generic parameter it corresponds to and return
1590 // the relevant type.
1591 let generics = match path.res {
1592 Res::Def(DefKind::Ctor(..), def_id) => {
1593 tcx.generics_of(tcx.parent(def_id).unwrap())
1595 Res::Def(_, def_id) => tcx.generics_of(def_id),
1596 Res::Err => return tcx.types.err,
1598 tcx.sess.delay_span_bug(
1600 &format!("unexpected const parent path def {:?}", res,),
1602 return tcx.types.err;
1610 if let ty::GenericParamDefKind::Const = param.kind {
1617 .map(|param| tcx.type_of(param.def_id))
1618 // This is no generic parameter associated with the arg. This is
1619 // probably from an extra arg where one is not needed.
1620 .unwrap_or(tcx.types.err)
1622 tcx.sess.delay_span_bug(
1624 &format!("unexpected const parent path {:?}", parent_node,),
1626 return tcx.types.err;
1631 tcx.sess.delay_span_bug(
1633 &format!("unexpected const parent in type_of_def_id(): {:?}", x),
1640 Node::GenericParam(param) => match ¶m.kind {
1641 hir::GenericParamKind::Type { default: Some(ref ty), .. } => icx.to_ty(ty),
1642 hir::GenericParamKind::Const { ty: ref hir_ty, .. } => {
1643 let ty = icx.to_ty(hir_ty);
1644 if !tcx.features().const_compare_raw_pointers {
1645 let err = match ty.peel_refs().kind {
1646 ty::FnPtr(_) => Some("function pointers"),
1647 ty::RawPtr(_) => Some("raw pointers"),
1650 if let Some(unsupported_type) = err {
1652 &tcx.sess.parse_sess,
1653 sym::const_compare_raw_pointers,
1656 "using {} as const generic parameters is unstable",
1663 if traits::search_for_structural_match_violation(param.hir_id, param.span, tcx, ty)
1670 "the types of const generic parameters must derive `PartialEq` and `Eq`",
1674 format!("`{}` doesn't derive both `PartialEq` and `Eq`", ty),
1680 x => bug!("unexpected non-type Node::GenericParam: {:?}", x),
1684 bug!("unexpected sort of node in type_of_def_id(): {:?}", x);
1689 fn find_opaque_ty_constraints(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> {
1690 use rustc_hir::{Expr, ImplItem, Item, TraitItem};
1692 debug!("find_opaque_ty_constraints({:?})", def_id);
1694 struct ConstraintLocator<'tcx> {
1697 // (first found type span, actual type, mapping from the opaque type's generic
1698 // parameters to the concrete type's generic parameters)
1700 // The mapping is an index for each use site of a generic parameter in the concrete type
1702 // The indices index into the generic parameters on the opaque type.
1703 found: Option<(Span, Ty<'tcx>, Vec<usize>)>,
1706 impl ConstraintLocator<'tcx> {
1707 fn check(&mut self, def_id: DefId) {
1708 // Don't try to check items that cannot possibly constrain the type.
1709 if !self.tcx.has_typeck_tables(def_id) {
1711 "find_opaque_ty_constraints: no constraint for `{:?}` at `{:?}`: no tables",
1712 self.def_id, def_id,
1716 // Calling `mir_borrowck` can lead to cycle errors through
1717 // const-checking, avoid calling it if we don't have to.
1718 if !self.tcx.typeck_tables_of(def_id).concrete_opaque_types.contains_key(&self.def_id) {
1720 "find_opaque_ty_constraints: no constraint for `{:?}` at `{:?}`",
1721 self.def_id, def_id,
1725 // Use borrowck to get the type with unerased regions.
1726 let ty = self.tcx.mir_borrowck(def_id).concrete_opaque_types.get(&self.def_id);
1727 if let Some(ty::ResolvedOpaqueTy { concrete_type, substs }) = ty {
1729 "find_opaque_ty_constraints: found constraint for `{:?}` at `{:?}`: {:?}",
1730 self.def_id, def_id, ty,
1733 // FIXME(oli-obk): trace the actual span from inference to improve errors.
1734 let span = self.tcx.def_span(def_id);
1735 // used to quickly look up the position of a generic parameter
1736 let mut index_map: FxHashMap<ty::ParamTy, usize> = FxHashMap::default();
1737 // Skipping binder is ok, since we only use this to find generic parameters and
1739 for (idx, subst) in substs.iter().enumerate() {
1740 if let GenericArgKind::Type(ty) = subst.unpack() {
1741 if let ty::Param(p) = ty.kind {
1742 if index_map.insert(p, idx).is_some() {
1743 // There was already an entry for `p`, meaning a generic parameter
1745 self.tcx.sess.span_err(
1748 "defining opaque type use restricts opaque \
1749 type by using the generic parameter `{}` twice",
1756 self.tcx.sess.delay_span_bug(
1759 "non-defining opaque ty use in defining scope: {:?}, {:?}",
1760 concrete_type, substs,
1766 // Compute the index within the opaque type for each generic parameter used in
1767 // the concrete type.
1768 let indices = concrete_type
1769 .subst(self.tcx, substs)
1771 .filter_map(|t| match &t.kind {
1772 ty::Param(p) => Some(*index_map.get(p).unwrap()),
1776 let is_param = |ty: Ty<'_>| match ty.kind {
1777 ty::Param(_) => true,
1780 let bad_substs: Vec<_> = substs
1783 .filter_map(|(i, k)| {
1784 if let GenericArgKind::Type(ty) = k.unpack() { Some((i, ty)) } else { None }
1786 .filter(|(_, ty)| !is_param(ty))
1789 if !bad_substs.is_empty() {
1790 let identity_substs = InternalSubsts::identity_for_item(self.tcx, self.def_id);
1791 for (i, bad_subst) in bad_substs {
1792 self.tcx.sess.span_err(
1795 "defining opaque type use does not fully define opaque type: \
1796 generic parameter `{}` is specified as concrete type `{}`",
1797 identity_substs.type_at(i),
1802 } else if let Some((prev_span, prev_ty, ref prev_indices)) = self.found {
1803 let mut ty = concrete_type.walk().fuse();
1804 let mut p_ty = prev_ty.walk().fuse();
1805 let iter_eq = (&mut ty).zip(&mut p_ty).all(|(t, p)| match (&t.kind, &p.kind) {
1806 // Type parameters are equal to any other type parameter for the purpose of
1807 // concrete type equality, as it is possible to obtain the same type just
1808 // by passing matching parameters to a function.
1809 (ty::Param(_), ty::Param(_)) => true,
1812 if !iter_eq || ty.next().is_some() || p_ty.next().is_some() {
1813 debug!("find_opaque_ty_constraints: span={:?}", span);
1814 // Found different concrete types for the opaque type.
1815 let mut err = self.tcx.sess.struct_span_err(
1817 "concrete type differs from previous defining opaque type use",
1821 format!("expected `{}`, got `{}`", prev_ty, concrete_type),
1823 err.span_note(prev_span, "previous use here");
1825 } else if indices != *prev_indices {
1826 // Found "same" concrete types, but the generic parameter order differs.
1827 let mut err = self.tcx.sess.struct_span_err(
1829 "concrete type's generic parameters differ from previous defining use",
1831 use std::fmt::Write;
1832 let mut s = String::new();
1833 write!(s, "expected [").unwrap();
1834 let list = |s: &mut String, indices: &Vec<usize>| {
1835 let mut indices = indices.iter().cloned();
1836 if let Some(first) = indices.next() {
1837 write!(s, "`{}`", substs[first]).unwrap();
1839 write!(s, ", `{}`", substs[i]).unwrap();
1843 list(&mut s, prev_indices);
1844 write!(s, "], got [").unwrap();
1845 list(&mut s, &indices);
1846 write!(s, "]").unwrap();
1847 err.span_label(span, s);
1848 err.span_note(prev_span, "previous use here");
1852 self.found = Some((span, concrete_type, indices));
1856 "find_opaque_ty_constraints: no constraint for `{:?}` at `{:?}`",
1857 self.def_id, def_id,
1863 impl<'tcx> intravisit::Visitor<'tcx> for ConstraintLocator<'tcx> {
1864 type Map = Map<'tcx>;
1866 fn nested_visit_map(&mut self) -> intravisit::NestedVisitorMap<'_, Self::Map> {
1867 intravisit::NestedVisitorMap::All(&self.tcx.hir())
1869 fn visit_expr(&mut self, ex: &'tcx Expr<'tcx>) {
1870 if let hir::ExprKind::Closure(..) = ex.kind {
1871 let def_id = self.tcx.hir().local_def_id(ex.hir_id);
1874 intravisit::walk_expr(self, ex);
1876 fn visit_item(&mut self, it: &'tcx Item<'tcx>) {
1877 debug!("find_existential_constraints: visiting {:?}", it);
1878 let def_id = self.tcx.hir().local_def_id(it.hir_id);
1879 // The opaque type itself or its children are not within its reveal scope.
1880 if def_id != self.def_id {
1882 intravisit::walk_item(self, it);
1885 fn visit_impl_item(&mut self, it: &'tcx ImplItem<'tcx>) {
1886 debug!("find_existential_constraints: visiting {:?}", it);
1887 let def_id = self.tcx.hir().local_def_id(it.hir_id);
1888 // The opaque type itself or its children are not within its reveal scope.
1889 if def_id != self.def_id {
1891 intravisit::walk_impl_item(self, it);
1894 fn visit_trait_item(&mut self, it: &'tcx TraitItem<'tcx>) {
1895 debug!("find_existential_constraints: visiting {:?}", it);
1896 let def_id = self.tcx.hir().local_def_id(it.hir_id);
1898 intravisit::walk_trait_item(self, it);
1902 let hir_id = tcx.hir().as_local_hir_id(def_id).unwrap();
1903 let scope = tcx.hir().get_defining_scope(hir_id);
1904 let mut locator = ConstraintLocator { def_id, tcx, found: None };
1906 debug!("find_opaque_ty_constraints: scope={:?}", scope);
1908 if scope == hir::CRATE_HIR_ID {
1909 intravisit::walk_crate(&mut locator, tcx.hir().krate());
1911 debug!("find_opaque_ty_constraints: scope={:?}", tcx.hir().get(scope));
1912 match tcx.hir().get(scope) {
1913 // We explicitly call `visit_*` methods, instead of using `intravisit::walk_*` methods
1914 // This allows our visitor to process the defining item itself, causing
1915 // it to pick up any 'sibling' defining uses.
1917 // For example, this code:
1920 // type Blah = impl Debug;
1921 // let my_closure = || -> Blah { true };
1925 // requires us to explicitly process `foo()` in order
1926 // to notice the defining usage of `Blah`.
1927 Node::Item(ref it) => locator.visit_item(it),
1928 Node::ImplItem(ref it) => locator.visit_impl_item(it),
1929 Node::TraitItem(ref it) => locator.visit_trait_item(it),
1930 other => bug!("{:?} is not a valid scope for an opaque type item", other),
1934 match locator.found {
1935 Some((_, ty, _)) => ty,
1937 let span = tcx.def_span(def_id);
1938 tcx.sess.span_err(span, "could not find defining uses");
1944 fn are_suggestable_generic_args(generic_args: &[hir::GenericArg<'_>]) -> bool {
1947 .filter_map(|arg| match arg {
1948 hir::GenericArg::Type(ty) => Some(ty),
1951 .any(is_suggestable_infer_ty)
1954 /// Whether `ty` is a type with `_` placeholders that can be infered. Used in diagnostics only to
1955 /// use inference to provide suggestions for the appropriate type if possible.
1956 fn is_suggestable_infer_ty(ty: &hir::Ty<'_>) -> bool {
1960 Slice(ty) | Array(ty, _) => is_suggestable_infer_ty(ty),
1961 Tup(tys) => tys.iter().any(is_suggestable_infer_ty),
1962 Ptr(mut_ty) | Rptr(_, mut_ty) => is_suggestable_infer_ty(mut_ty.ty),
1963 Def(_, generic_args) => are_suggestable_generic_args(generic_args),
1964 Path(hir::QPath::TypeRelative(ty, segment)) => {
1965 is_suggestable_infer_ty(ty) || are_suggestable_generic_args(segment.generic_args().args)
1967 Path(hir::QPath::Resolved(ty_opt, hir::Path { segments, .. })) => {
1968 ty_opt.map_or(false, is_suggestable_infer_ty)
1971 .any(|segment| are_suggestable_generic_args(segment.generic_args().args))
1977 pub fn get_infer_ret_ty(output: &'hir hir::FunctionRetTy<'hir>) -> Option<&'hir hir::Ty<'hir>> {
1978 if let hir::FunctionRetTy::Return(ref ty) = output {
1979 if is_suggestable_infer_ty(ty) {
1986 fn fn_sig(tcx: TyCtxt<'_>, def_id: DefId) -> ty::PolyFnSig<'_> {
1987 use rustc_hir::Node::*;
1990 let hir_id = tcx.hir().as_local_hir_id(def_id).unwrap();
1992 let icx = ItemCtxt::new(tcx, def_id);
1994 match tcx.hir().get(hir_id) {
1995 TraitItem(hir::TraitItem {
1996 kind: TraitItemKind::Method(sig, TraitMethod::Provided(_)),
2001 | ImplItem(hir::ImplItem { kind: ImplItemKind::Method(sig, _), ident, generics, .. })
2002 | Item(hir::Item { kind: ItemKind::Fn(sig, generics, _), ident, .. }) => {
2003 match get_infer_ret_ty(&sig.decl.output) {
2005 let fn_sig = tcx.typeck_tables_of(def_id).liberated_fn_sigs()[hir_id];
2006 let mut visitor = PlaceholderHirTyCollector::default();
2007 visitor.visit_ty(ty);
2008 let mut diag = bad_placeholder_type(tcx, visitor.0);
2009 let ret_ty = fn_sig.output();
2010 if ret_ty != tcx.types.err {
2011 diag.span_suggestion(
2013 "replace with the correct return type",
2015 Applicability::MaybeIncorrect,
2019 ty::Binder::bind(fn_sig)
2021 None => AstConv::ty_of_fn(
2023 sig.header.unsafety,
2026 &generics.params[..],
2032 TraitItem(hir::TraitItem {
2033 kind: TraitItemKind::Method(FnSig { header, decl }, _),
2037 }) => AstConv::ty_of_fn(
2042 &generics.params[..],
2046 ForeignItem(&hir::ForeignItem { kind: ForeignItemKind::Fn(ref fn_decl, _, _), .. }) => {
2047 let abi = tcx.hir().get_foreign_abi(hir_id);
2048 compute_sig_of_foreign_fn_decl(tcx, def_id, fn_decl, abi)
2051 Ctor(data) | Variant(hir::Variant { data, .. }) if data.ctor_hir_id().is_some() => {
2052 let ty = tcx.type_of(tcx.hir().get_parent_did(hir_id));
2054 data.fields().iter().map(|f| tcx.type_of(tcx.hir().local_def_id(f.hir_id)));
2055 ty::Binder::bind(tcx.mk_fn_sig(
2059 hir::Unsafety::Normal,
2064 Expr(&hir::Expr { kind: hir::ExprKind::Closure(..), .. }) => {
2065 // Closure signatures are not like other function
2066 // signatures and cannot be accessed through `fn_sig`. For
2067 // example, a closure signature excludes the `self`
2068 // argument. In any case they are embedded within the
2069 // closure type as part of the `ClosureSubsts`.
2072 // the signature of a closure, you should use the
2073 // `closure_sig` method on the `ClosureSubsts`:
2075 // closure_substs.sig(def_id, tcx)
2077 // or, inside of an inference context, you can use
2079 // infcx.closure_sig(def_id, closure_substs)
2080 bug!("to get the signature of a closure, use `closure_sig()` not `fn_sig()`");
2084 bug!("unexpected sort of node in fn_sig(): {:?}", x);
2089 fn impl_trait_ref(tcx: TyCtxt<'_>, def_id: DefId) -> Option<ty::TraitRef<'_>> {
2090 let icx = ItemCtxt::new(tcx, def_id);
2092 let hir_id = tcx.hir().as_local_hir_id(def_id).unwrap();
2093 match tcx.hir().expect_item(hir_id).kind {
2094 hir::ItemKind::Impl { ref of_trait, .. } => of_trait.as_ref().map(|ast_trait_ref| {
2095 let selfty = tcx.type_of(def_id);
2096 AstConv::instantiate_mono_trait_ref(&icx, ast_trait_ref, selfty)
2102 fn impl_polarity(tcx: TyCtxt<'_>, def_id: DefId) -> ty::ImplPolarity {
2103 let hir_id = tcx.hir().as_local_hir_id(def_id).unwrap();
2104 let is_rustc_reservation = tcx.has_attr(def_id, sym::rustc_reservation_impl);
2105 let item = tcx.hir().expect_item(hir_id);
2107 hir::ItemKind::Impl { polarity: hir::ImplPolarity::Negative, .. } => {
2108 if is_rustc_reservation {
2109 tcx.sess.span_err(item.span, "reservation impls can't be negative");
2111 ty::ImplPolarity::Negative
2113 hir::ItemKind::Impl { polarity: hir::ImplPolarity::Positive, of_trait: None, .. } => {
2114 if is_rustc_reservation {
2115 tcx.sess.span_err(item.span, "reservation impls can't be inherent");
2117 ty::ImplPolarity::Positive
2119 hir::ItemKind::Impl {
2120 polarity: hir::ImplPolarity::Positive, of_trait: Some(_), ..
2122 if is_rustc_reservation {
2123 ty::ImplPolarity::Reservation
2125 ty::ImplPolarity::Positive
2128 ref item => bug!("impl_polarity: {:?} not an impl", item),
2132 /// Returns the early-bound lifetimes declared in this generics
2133 /// listing. For anything other than fns/methods, this is just all
2134 /// the lifetimes that are declared. For fns or methods, we have to
2135 /// screen out those that do not appear in any where-clauses etc using
2136 /// `resolve_lifetime::early_bound_lifetimes`.
2137 fn early_bound_lifetimes_from_generics<'a, 'tcx: 'a>(
2139 generics: &'a hir::Generics<'a>,
2140 ) -> impl Iterator<Item = &'a hir::GenericParam<'a>> + Captures<'tcx> {
2141 generics.params.iter().filter(move |param| match param.kind {
2142 GenericParamKind::Lifetime { .. } => !tcx.is_late_bound(param.hir_id),
2147 /// Returns a list of type predicates for the definition with ID `def_id`, including inferred
2148 /// lifetime constraints. This includes all predicates returned by `explicit_predicates_of`, plus
2149 /// inferred constraints concerning which regions outlive other regions.
2150 fn predicates_defined_on(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicates<'_> {
2151 debug!("predicates_defined_on({:?})", def_id);
2152 let mut result = tcx.explicit_predicates_of(def_id);
2153 debug!("predicates_defined_on: explicit_predicates_of({:?}) = {:?}", def_id, result,);
2154 let inferred_outlives = tcx.inferred_outlives_of(def_id);
2155 if !inferred_outlives.is_empty() {
2157 "predicates_defined_on: inferred_outlives_of({:?}) = {:?}",
2158 def_id, inferred_outlives,
2160 if result.predicates.is_empty() {
2161 result.predicates = inferred_outlives;
2163 result.predicates = tcx
2165 .alloc_from_iter(result.predicates.iter().chain(inferred_outlives).copied());
2168 debug!("predicates_defined_on({:?}) = {:?}", def_id, result);
2172 /// Returns a list of all type predicates (explicit and implicit) for the definition with
2173 /// ID `def_id`. This includes all predicates returned by `predicates_defined_on`, plus
2174 /// `Self: Trait` predicates for traits.
2175 fn predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicates<'_> {
2176 let mut result = tcx.predicates_defined_on(def_id);
2178 if tcx.is_trait(def_id) {
2179 // For traits, add `Self: Trait` predicate. This is
2180 // not part of the predicates that a user writes, but it
2181 // is something that one must prove in order to invoke a
2182 // method or project an associated type.
2184 // In the chalk setup, this predicate is not part of the
2185 // "predicates" for a trait item. But it is useful in
2186 // rustc because if you directly (e.g.) invoke a trait
2187 // method like `Trait::method(...)`, you must naturally
2188 // prove that the trait applies to the types that were
2189 // used, and adding the predicate into this list ensures
2190 // that this is done.
2191 let span = tcx.def_span(def_id);
2193 tcx.arena.alloc_from_iter(result.predicates.iter().copied().chain(std::iter::once((
2194 ty::TraitRef::identity(tcx, def_id).without_const().to_predicate(),
2198 debug!("predicates_of(def_id={:?}) = {:?}", def_id, result);
2202 /// Returns a list of user-specified type predicates for the definition with ID `def_id`.
2203 /// N.B., this does not include any implied/inferred constraints.
2204 fn explicit_predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicates<'_> {
2205 use rustc_data_structures::fx::FxHashSet;
2208 debug!("explicit_predicates_of(def_id={:?})", def_id);
2210 /// A data structure with unique elements, which preserves order of insertion.
2211 /// Preserving the order of insertion is important here so as not to break
2212 /// compile-fail UI tests.
2213 // FIXME(eddyb) just use `IndexSet` from `indexmap`.
2214 struct UniquePredicates<'tcx> {
2215 predicates: Vec<(ty::Predicate<'tcx>, Span)>,
2216 uniques: FxHashSet<(ty::Predicate<'tcx>, Span)>,
2219 impl<'tcx> UniquePredicates<'tcx> {
2221 UniquePredicates { predicates: vec![], uniques: FxHashSet::default() }
2224 fn push(&mut self, value: (ty::Predicate<'tcx>, Span)) {
2225 if self.uniques.insert(value) {
2226 self.predicates.push(value);
2230 fn extend<I: IntoIterator<Item = (ty::Predicate<'tcx>, Span)>>(&mut self, iter: I) {
2237 let hir_id = tcx.hir().as_local_hir_id(def_id).unwrap();
2238 let node = tcx.hir().get(hir_id);
2240 let mut is_trait = None;
2241 let mut is_default_impl_trait = None;
2243 let icx = ItemCtxt::new(tcx, def_id);
2244 let constness = icx.default_constness_for_trait_bounds();
2246 const NO_GENERICS: &hir::Generics<'_> = &hir::Generics::empty();
2248 let mut predicates = UniquePredicates::new();
2250 let ast_generics = match node {
2251 Node::TraitItem(item) => &item.generics,
2253 Node::ImplItem(item) => match item.kind {
2254 ImplItemKind::OpaqueTy(ref bounds) => {
2255 ty::print::with_no_queries(|| {
2256 let substs = InternalSubsts::identity_for_item(tcx, def_id);
2257 let opaque_ty = tcx.mk_opaque(def_id, substs);
2259 "explicit_predicates_of({:?}): created opaque type {:?}",
2263 // Collect the bounds, i.e., the `A + B + 'c` in `impl A + B + 'c`.
2264 let bounds = AstConv::compute_bounds(
2268 SizedByDefault::Yes,
2269 tcx.def_span(def_id),
2272 predicates.extend(bounds.predicates(tcx, opaque_ty));
2276 _ => &item.generics,
2279 Node::Item(item) => {
2281 ItemKind::Impl { defaultness, ref generics, .. } => {
2282 if defaultness.is_default() {
2283 is_default_impl_trait = tcx.impl_trait_ref(def_id);
2287 ItemKind::Fn(.., ref generics, _)
2288 | ItemKind::TyAlias(_, ref generics)
2289 | ItemKind::Enum(_, ref generics)
2290 | ItemKind::Struct(_, ref generics)
2291 | ItemKind::Union(_, ref generics) => generics,
2293 ItemKind::Trait(_, _, ref generics, .., items) => {
2294 is_trait = Some((ty::TraitRef::identity(tcx, def_id), items));
2297 ItemKind::TraitAlias(ref generics, _) => {
2298 is_trait = Some((ty::TraitRef::identity(tcx, def_id), &[]));
2301 ItemKind::OpaqueTy(OpaqueTy {
2307 let bounds_predicates = ty::print::with_no_queries(|| {
2308 let substs = InternalSubsts::identity_for_item(tcx, def_id);
2309 let opaque_ty = tcx.mk_opaque(def_id, substs);
2311 // Collect the bounds, i.e., the `A + B + 'c` in `impl A + B + 'c`.
2312 let bounds = AstConv::compute_bounds(
2316 SizedByDefault::Yes,
2317 tcx.def_span(def_id),
2320 bounds.predicates(tcx, opaque_ty)
2322 if impl_trait_fn.is_some() {
2324 return ty::GenericPredicates {
2326 predicates: tcx.arena.alloc_from_iter(bounds_predicates),
2329 // named opaque types
2330 predicates.extend(bounds_predicates);
2339 Node::ForeignItem(item) => match item.kind {
2340 ForeignItemKind::Static(..) => NO_GENERICS,
2341 ForeignItemKind::Fn(_, _, ref generics) => generics,
2342 ForeignItemKind::Type => NO_GENERICS,
2348 let generics = tcx.generics_of(def_id);
2349 let parent_count = generics.parent_count as u32;
2350 let has_own_self = generics.has_self && parent_count == 0;
2352 // Below we'll consider the bounds on the type parameters (including `Self`)
2353 // and the explicit where-clauses, but to get the full set of predicates
2354 // on a trait we need to add in the supertrait bounds and bounds found on
2355 // associated types.
2356 if let Some((_trait_ref, _)) = is_trait {
2357 predicates.extend(tcx.super_predicates_of(def_id).predicates.iter().cloned());
2360 // In default impls, we can assume that the self type implements
2361 // the trait. So in:
2363 // default impl Foo for Bar { .. }
2365 // we add a default where clause `Foo: Bar`. We do a similar thing for traits
2366 // (see below). Recall that a default impl is not itself an impl, but rather a
2367 // set of defaults that can be incorporated into another impl.
2368 if let Some(trait_ref) = is_default_impl_trait {
2370 trait_ref.to_poly_trait_ref().without_const().to_predicate(),
2371 tcx.def_span(def_id),
2375 // Collect the region predicates that were declared inline as
2376 // well. In the case of parameters declared on a fn or method, we
2377 // have to be careful to only iterate over early-bound regions.
2378 let mut index = parent_count + has_own_self as u32;
2379 for param in early_bound_lifetimes_from_generics(tcx, ast_generics) {
2380 let region = tcx.mk_region(ty::ReEarlyBound(ty::EarlyBoundRegion {
2381 def_id: tcx.hir().local_def_id(param.hir_id),
2383 name: param.name.ident().name,
2388 GenericParamKind::Lifetime { .. } => {
2389 param.bounds.iter().for_each(|bound| match bound {
2390 hir::GenericBound::Outlives(lt) => {
2391 let bound = AstConv::ast_region_to_region(&icx, <, None);
2392 let outlives = ty::Binder::bind(ty::OutlivesPredicate(region, bound));
2393 predicates.push((outlives.to_predicate(), lt.span));
2402 // Collect the predicates that were written inline by the user on each
2403 // type parameter (e.g., `<T: Foo>`).
2404 for param in ast_generics.params {
2405 if let GenericParamKind::Type { .. } = param.kind {
2406 let name = param.name.ident().name;
2407 let param_ty = ty::ParamTy::new(index, name).to_ty(tcx);
2410 let sized = SizedByDefault::Yes;
2411 let bounds = AstConv::compute_bounds(&icx, param_ty, ¶m.bounds, sized, param.span);
2412 predicates.extend(bounds.predicates(tcx, param_ty));
2416 // Add in the bounds that appear in the where-clause.
2417 let where_clause = &ast_generics.where_clause;
2418 for predicate in where_clause.predicates {
2420 &hir::WherePredicate::BoundPredicate(ref bound_pred) => {
2421 let ty = icx.to_ty(&bound_pred.bounded_ty);
2423 // Keep the type around in a dummy predicate, in case of no bounds.
2424 // That way, `where Ty:` is not a complete noop (see #53696) and `Ty`
2425 // is still checked for WF.
2426 if bound_pred.bounds.is_empty() {
2427 if let ty::Param(_) = ty.kind {
2428 // This is a `where T:`, which can be in the HIR from the
2429 // transformation that moves `?Sized` to `T`'s declaration.
2430 // We can skip the predicate because type parameters are
2431 // trivially WF, but also we *should*, to avoid exposing
2432 // users who never wrote `where Type:,` themselves, to
2433 // compiler/tooling bugs from not handling WF predicates.
2435 let span = bound_pred.bounded_ty.span;
2436 let re_root_empty = tcx.lifetimes.re_root_empty;
2437 let predicate = ty::OutlivesPredicate(ty, re_root_empty);
2439 ty::Predicate::TypeOutlives(ty::Binder::dummy(predicate)),
2445 for bound in bound_pred.bounds.iter() {
2447 &hir::GenericBound::Trait(ref poly_trait_ref, modifier) => {
2448 let constness = match modifier {
2449 hir::TraitBoundModifier::MaybeConst => hir::Constness::NotConst,
2450 hir::TraitBoundModifier::None => constness,
2451 hir::TraitBoundModifier::Maybe => bug!("this wasn't handled"),
2454 let mut bounds = Bounds::default();
2455 let _ = AstConv::instantiate_poly_trait_ref(
2462 predicates.extend(bounds.predicates(tcx, ty));
2465 &hir::GenericBound::Outlives(ref lifetime) => {
2466 let region = AstConv::ast_region_to_region(&icx, lifetime, None);
2467 let pred = ty::Binder::bind(ty::OutlivesPredicate(ty, region));
2468 predicates.push((ty::Predicate::TypeOutlives(pred), lifetime.span))
2474 &hir::WherePredicate::RegionPredicate(ref region_pred) => {
2475 let r1 = AstConv::ast_region_to_region(&icx, ®ion_pred.lifetime, None);
2476 predicates.extend(region_pred.bounds.iter().map(|bound| {
2477 let (r2, span) = match bound {
2478 hir::GenericBound::Outlives(lt) => {
2479 (AstConv::ast_region_to_region(&icx, lt, None), lt.span)
2483 let pred = ty::Binder::bind(ty::OutlivesPredicate(r1, r2));
2485 (ty::Predicate::RegionOutlives(pred), span)
2489 &hir::WherePredicate::EqPredicate(..) => {
2495 // Add predicates from associated type bounds.
2496 if let Some((self_trait_ref, trait_items)) = is_trait {
2497 predicates.extend(trait_items.iter().flat_map(|trait_item_ref| {
2498 associated_item_predicates(tcx, def_id, self_trait_ref, trait_item_ref)
2502 let mut predicates = predicates.predicates;
2504 // Subtle: before we store the predicates into the tcx, we
2505 // sort them so that predicates like `T: Foo<Item=U>` come
2506 // before uses of `U`. This avoids false ambiguity errors
2507 // in trait checking. See `setup_constraining_predicates`
2509 if let Node::Item(&Item { kind: ItemKind::Impl { .. }, .. }) = node {
2510 let self_ty = tcx.type_of(def_id);
2511 let trait_ref = tcx.impl_trait_ref(def_id);
2512 cgp::setup_constraining_predicates(
2516 &mut cgp::parameters_for_impl(self_ty, trait_ref),
2520 let result = ty::GenericPredicates {
2521 parent: generics.parent,
2522 predicates: tcx.arena.alloc_from_iter(predicates),
2524 debug!("explicit_predicates_of(def_id={:?}) = {:?}", def_id, result);
2528 fn associated_item_predicates(
2531 self_trait_ref: ty::TraitRef<'tcx>,
2532 trait_item_ref: &hir::TraitItemRef,
2533 ) -> Vec<(ty::Predicate<'tcx>, Span)> {
2534 let trait_item = tcx.hir().trait_item(trait_item_ref.id);
2535 let item_def_id = tcx.hir().local_def_id(trait_item_ref.id.hir_id);
2536 let bounds = match trait_item.kind {
2537 hir::TraitItemKind::Type(ref bounds, _) => bounds,
2538 _ => return Vec::new(),
2541 let is_gat = !tcx.generics_of(item_def_id).params.is_empty();
2543 let mut had_error = false;
2545 let mut unimplemented_error = |arg_kind: &str| {
2550 &format!("{}-generic associated types are not yet implemented", arg_kind),
2553 "for more information, see issue #44265 \
2554 <https://github.com/rust-lang/rust/issues/44265> for more information",
2561 let mk_bound_param = |param: &ty::GenericParamDef, _: &_| {
2563 ty::GenericParamDefKind::Lifetime => tcx
2564 .mk_region(ty::RegionKind::ReLateBound(
2566 ty::BoundRegion::BrNamed(param.def_id, param.name),
2569 // FIXME(generic_associated_types): Use bound types and constants
2570 // once they are handled by the trait system.
2571 ty::GenericParamDefKind::Type { .. } => {
2572 unimplemented_error("type");
2573 tcx.types.err.into()
2575 ty::GenericParamDefKind::Const => {
2576 unimplemented_error("const");
2577 tcx.consts.err.into()
2582 let bound_substs = if is_gat {
2585 // trait X<'a, B, const C: usize> {
2586 // type T<'d, E, const F: usize>: Default;
2589 // We need to create predicates on the trait:
2591 // for<'d, E, const F: usize>
2592 // <Self as X<'a, B, const C: usize>>::T<'d, E, const F: usize>: Sized + Default
2594 // We substitute escaping bound parameters for the generic
2595 // arguments to the associated type which are then bound by
2596 // the `Binder` around the the predicate.
2598 // FIXME(generic_associated_types): Currently only lifetimes are handled.
2599 self_trait_ref.substs.extend_to(tcx, item_def_id, mk_bound_param)
2601 self_trait_ref.substs
2604 let assoc_ty = tcx.mk_projection(tcx.hir().local_def_id(trait_item.hir_id), bound_substs);
2606 let bounds = AstConv::compute_bounds(
2607 &ItemCtxt::new(tcx, def_id),
2610 SizedByDefault::Yes,
2614 let predicates = bounds.predicates(tcx, assoc_ty);
2617 // We use shifts to get the regions that we're substituting to
2618 // be bound by the binders in the `Predicate`s rather that
2620 let shifted_in = ty::fold::shift_vars(tcx, &predicates, 1);
2621 let substituted = shifted_in.subst(tcx, bound_substs);
2622 ty::fold::shift_out_vars(tcx, &substituted, 1)
2628 /// Converts a specific `GenericBound` from the AST into a set of
2629 /// predicates that apply to the self type. A vector is returned
2630 /// because this can be anywhere from zero predicates (`T: ?Sized` adds no
2631 /// predicates) to one (`T: Foo`) to many (`T: Bar<X = i32>` adds `T: Bar`
2632 /// and `<T as Bar>::X == i32`).
2633 fn predicates_from_bound<'tcx>(
2634 astconv: &dyn AstConv<'tcx>,
2636 bound: &'tcx hir::GenericBound<'tcx>,
2637 constness: hir::Constness,
2638 ) -> Vec<(ty::Predicate<'tcx>, Span)> {
2640 hir::GenericBound::Trait(ref tr, modifier) => {
2641 let constness = match modifier {
2642 hir::TraitBoundModifier::Maybe => return vec![],
2643 hir::TraitBoundModifier::MaybeConst => hir::Constness::NotConst,
2644 hir::TraitBoundModifier::None => constness,
2647 let mut bounds = Bounds::default();
2648 let _ = astconv.instantiate_poly_trait_ref(tr, constness, param_ty, &mut bounds);
2649 bounds.predicates(astconv.tcx(), param_ty)
2651 hir::GenericBound::Outlives(ref lifetime) => {
2652 let region = astconv.ast_region_to_region(lifetime, None);
2653 let pred = ty::Binder::bind(ty::OutlivesPredicate(param_ty, region));
2654 vec![(ty::Predicate::TypeOutlives(pred), lifetime.span)]
2659 fn compute_sig_of_foreign_fn_decl<'tcx>(
2662 decl: &'tcx hir::FnDecl<'tcx>,
2664 ) -> ty::PolyFnSig<'tcx> {
2665 let unsafety = if abi == abi::Abi::RustIntrinsic {
2666 intrinsic_operation_unsafety(&tcx.item_name(def_id).as_str())
2668 hir::Unsafety::Unsafe
2670 let fty = AstConv::ty_of_fn(&ItemCtxt::new(tcx, def_id), unsafety, abi, decl, &[], None);
2672 // Feature gate SIMD types in FFI, since I am not sure that the
2673 // ABIs are handled at all correctly. -huonw
2674 if abi != abi::Abi::RustIntrinsic
2675 && abi != abi::Abi::PlatformIntrinsic
2676 && !tcx.features().simd_ffi
2678 let check = |ast_ty: &hir::Ty<'_>, ty: Ty<'_>| {
2684 "use of SIMD type `{}` in FFI is highly experimental and \
2685 may result in invalid code",
2686 tcx.hir().hir_to_pretty_string(ast_ty.hir_id)
2689 .help("add `#![feature(simd_ffi)]` to the crate attributes to enable")
2693 for (input, ty) in decl.inputs.iter().zip(*fty.inputs().skip_binder()) {
2696 if let hir::FunctionRetTy::Return(ref ty) = decl.output {
2697 check(&ty, *fty.output().skip_binder())
2704 fn is_foreign_item(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
2705 match tcx.hir().get_if_local(def_id) {
2706 Some(Node::ForeignItem(..)) => true,
2708 _ => bug!("is_foreign_item applied to non-local def-id {:?}", def_id),
2712 fn static_mutability(tcx: TyCtxt<'_>, def_id: DefId) -> Option<hir::Mutability> {
2713 match tcx.hir().get_if_local(def_id) {
2714 Some(Node::Item(&hir::Item { kind: hir::ItemKind::Static(_, mutbl, _), .. }))
2715 | Some(Node::ForeignItem(&hir::ForeignItem {
2716 kind: hir::ForeignItemKind::Static(_, mutbl),
2720 _ => bug!("static_mutability applied to non-local def-id {:?}", def_id),
2724 fn from_target_feature(
2727 attr: &ast::Attribute,
2728 whitelist: &FxHashMap<String, Option<Symbol>>,
2729 target_features: &mut Vec<Symbol>,
2731 let list = match attr.meta_item_list() {
2735 let bad_item = |span| {
2736 let msg = "malformed `target_feature` attribute input";
2737 let code = "enable = \"..\"".to_owned();
2739 .struct_span_err(span, &msg)
2740 .span_suggestion(span, "must be of the form", code, Applicability::HasPlaceholders)
2743 let rust_features = tcx.features();
2745 // Only `enable = ...` is accepted in the meta-item list.
2746 if !item.check_name(sym::enable) {
2747 bad_item(item.span());
2751 // Must be of the form `enable = "..."` (a string).
2752 let value = match item.value_str() {
2753 Some(value) => value,
2755 bad_item(item.span());
2760 // We allow comma separation to enable multiple features.
2761 target_features.extend(value.as_str().split(',').filter_map(|feature| {
2762 // Only allow whitelisted features per platform.
2763 let feature_gate = match whitelist.get(feature) {
2767 format!("the feature named `{}` is not valid for this target", feature);
2768 let mut err = tcx.sess.struct_span_err(item.span(), &msg);
2771 format!("`{}` is not valid for this target", feature),
2773 if feature.starts_with("+") {
2774 let valid = whitelist.contains_key(&feature[1..]);
2776 err.help("consider removing the leading `+` in the feature name");
2784 // Only allow features whose feature gates have been enabled.
2785 let allowed = match feature_gate.as_ref().map(|s| *s) {
2786 Some(sym::arm_target_feature) => rust_features.arm_target_feature,
2787 Some(sym::aarch64_target_feature) => rust_features.aarch64_target_feature,
2788 Some(sym::hexagon_target_feature) => rust_features.hexagon_target_feature,
2789 Some(sym::powerpc_target_feature) => rust_features.powerpc_target_feature,
2790 Some(sym::mips_target_feature) => rust_features.mips_target_feature,
2791 Some(sym::avx512_target_feature) => rust_features.avx512_target_feature,
2792 Some(sym::mmx_target_feature) => rust_features.mmx_target_feature,
2793 Some(sym::sse4a_target_feature) => rust_features.sse4a_target_feature,
2794 Some(sym::tbm_target_feature) => rust_features.tbm_target_feature,
2795 Some(sym::wasm_target_feature) => rust_features.wasm_target_feature,
2796 Some(sym::cmpxchg16b_target_feature) => rust_features.cmpxchg16b_target_feature,
2797 Some(sym::adx_target_feature) => rust_features.adx_target_feature,
2798 Some(sym::movbe_target_feature) => rust_features.movbe_target_feature,
2799 Some(sym::rtm_target_feature) => rust_features.rtm_target_feature,
2800 Some(sym::f16c_target_feature) => rust_features.f16c_target_feature,
2801 Some(name) => bug!("unknown target feature gate {}", name),
2804 if !allowed && id.is_local() {
2806 &tcx.sess.parse_sess,
2807 feature_gate.unwrap(),
2809 &format!("the target feature `{}` is currently unstable", feature),
2813 Some(Symbol::intern(feature))
2818 fn linkage_by_name(tcx: TyCtxt<'_>, def_id: DefId, name: &str) -> Linkage {
2819 use rustc::mir::mono::Linkage::*;
2821 // Use the names from src/llvm/docs/LangRef.rst here. Most types are only
2822 // applicable to variable declarations and may not really make sense for
2823 // Rust code in the first place but whitelist them anyway and trust that
2824 // the user knows what s/he's doing. Who knows, unanticipated use cases
2825 // may pop up in the future.
2827 // ghost, dllimport, dllexport and linkonce_odr_autohide are not supported
2828 // and don't have to be, LLVM treats them as no-ops.
2830 "appending" => Appending,
2831 "available_externally" => AvailableExternally,
2833 "extern_weak" => ExternalWeak,
2834 "external" => External,
2835 "internal" => Internal,
2836 "linkonce" => LinkOnceAny,
2837 "linkonce_odr" => LinkOnceODR,
2838 "private" => Private,
2840 "weak_odr" => WeakODR,
2842 let span = tcx.hir().span_if_local(def_id);
2843 if let Some(span) = span {
2844 tcx.sess.span_fatal(span, "invalid linkage specified")
2846 tcx.sess.fatal(&format!("invalid linkage specified: {}", name))
2852 fn codegen_fn_attrs(tcx: TyCtxt<'_>, id: DefId) -> CodegenFnAttrs {
2853 let attrs = tcx.get_attrs(id);
2855 let mut codegen_fn_attrs = CodegenFnAttrs::new();
2857 let whitelist = tcx.target_features_whitelist(LOCAL_CRATE);
2859 let mut inline_span = None;
2860 let mut link_ordinal_span = None;
2861 let mut no_sanitize_span = None;
2862 for attr in attrs.iter() {
2863 if attr.check_name(sym::cold) {
2864 codegen_fn_attrs.flags |= CodegenFnAttrFlags::COLD;
2865 } else if attr.check_name(sym::rustc_allocator) {
2866 codegen_fn_attrs.flags |= CodegenFnAttrFlags::ALLOCATOR;
2867 } else if attr.check_name(sym::unwind) {
2868 codegen_fn_attrs.flags |= CodegenFnAttrFlags::UNWIND;
2869 } else if attr.check_name(sym::ffi_returns_twice) {
2870 if tcx.is_foreign_item(id) {
2871 codegen_fn_attrs.flags |= CodegenFnAttrFlags::FFI_RETURNS_TWICE;
2873 // `#[ffi_returns_twice]` is only allowed `extern fn`s.
2878 "`#[ffi_returns_twice]` may only be used on foreign functions"
2882 } else if attr.check_name(sym::rustc_allocator_nounwind) {
2883 codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_ALLOCATOR_NOUNWIND;
2884 } else if attr.check_name(sym::naked) {
2885 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NAKED;
2886 } else if attr.check_name(sym::no_mangle) {
2887 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_MANGLE;
2888 } else if attr.check_name(sym::rustc_std_internal_symbol) {
2889 codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL;
2890 } else if attr.check_name(sym::no_debug) {
2891 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_DEBUG;
2892 } else if attr.check_name(sym::used) {
2893 codegen_fn_attrs.flags |= CodegenFnAttrFlags::USED;
2894 } else if attr.check_name(sym::thread_local) {
2895 codegen_fn_attrs.flags |= CodegenFnAttrFlags::THREAD_LOCAL;
2896 } else if attr.check_name(sym::track_caller) {
2897 if tcx.fn_sig(id).abi() != abi::Abi::Rust {
2898 struct_span_err!(tcx.sess, attr.span, E0737, "`#[track_caller]` requires Rust ABI")
2901 codegen_fn_attrs.flags |= CodegenFnAttrFlags::TRACK_CALLER;
2902 } else if attr.check_name(sym::export_name) {
2903 if let Some(s) = attr.value_str() {
2904 if s.as_str().contains("\0") {
2905 // `#[export_name = ...]` will be converted to a null-terminated string,
2906 // so it may not contain any null characters.
2911 "`export_name` may not contain null characters"
2915 codegen_fn_attrs.export_name = Some(s);
2917 } else if attr.check_name(sym::target_feature) {
2918 if tcx.fn_sig(id).unsafety() == Unsafety::Normal {
2919 let msg = "`#[target_feature(..)]` can only be applied to `unsafe` functions";
2921 .struct_span_err(attr.span, msg)
2922 .span_label(attr.span, "can only be applied to `unsafe` functions")
2923 .span_label(tcx.def_span(id), "not an `unsafe` function")
2926 from_target_feature(tcx, id, attr, &whitelist, &mut codegen_fn_attrs.target_features);
2927 } else if attr.check_name(sym::linkage) {
2928 if let Some(val) = attr.value_str() {
2929 codegen_fn_attrs.linkage = Some(linkage_by_name(tcx, id, &val.as_str()));
2931 } else if attr.check_name(sym::link_section) {
2932 if let Some(val) = attr.value_str() {
2933 if val.as_str().bytes().any(|b| b == 0) {
2935 "illegal null byte in link_section \
2939 tcx.sess.span_err(attr.span, &msg);
2941 codegen_fn_attrs.link_section = Some(val);
2944 } else if attr.check_name(sym::link_name) {
2945 codegen_fn_attrs.link_name = attr.value_str();
2946 } else if attr.check_name(sym::link_ordinal) {
2947 link_ordinal_span = Some(attr.span);
2948 if let ordinal @ Some(_) = check_link_ordinal(tcx, attr) {
2949 codegen_fn_attrs.link_ordinal = ordinal;
2951 } else if attr.check_name(sym::no_sanitize) {
2952 no_sanitize_span = Some(attr.span);
2953 if let Some(list) = attr.meta_item_list() {
2954 for item in list.iter() {
2955 if item.check_name(sym::address) {
2956 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_SANITIZE_ADDRESS;
2957 } else if item.check_name(sym::memory) {
2958 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_SANITIZE_MEMORY;
2959 } else if item.check_name(sym::thread) {
2960 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_SANITIZE_THREAD;
2963 .struct_span_err(item.span(), "invalid argument for `no_sanitize`")
2964 .note("expected one of: `address`, `memory` or `thread`")
2972 codegen_fn_attrs.inline = attrs.iter().fold(InlineAttr::None, |ia, attr| {
2973 if !attr.has_name(sym::inline) {
2976 match attr.meta().map(|i| i.kind) {
2977 Some(MetaItemKind::Word) => {
2981 Some(MetaItemKind::List(ref items)) => {
2983 inline_span = Some(attr.span);
2984 if items.len() != 1 {
2986 tcx.sess.diagnostic(),
2989 "expected one argument"
2993 } else if list_contains_name(&items[..], sym::always) {
2995 } else if list_contains_name(&items[..], sym::never) {
2999 tcx.sess.diagnostic(),
3009 Some(MetaItemKind::NameValue(_)) => ia,
3014 codegen_fn_attrs.optimize = attrs.iter().fold(OptimizeAttr::None, |ia, attr| {
3015 if !attr.has_name(sym::optimize) {
3018 let err = |sp, s| struct_span_err!(tcx.sess.diagnostic(), sp, E0722, "{}", s).emit();
3019 match attr.meta().map(|i| i.kind) {
3020 Some(MetaItemKind::Word) => {
3021 err(attr.span, "expected one argument");
3024 Some(MetaItemKind::List(ref items)) => {
3026 inline_span = Some(attr.span);
3027 if items.len() != 1 {
3028 err(attr.span, "expected one argument");
3030 } else if list_contains_name(&items[..], sym::size) {
3032 } else if list_contains_name(&items[..], sym::speed) {
3035 err(items[0].span(), "invalid argument");
3039 Some(MetaItemKind::NameValue(_)) => ia,
3044 // If a function uses #[target_feature] it can't be inlined into general
3045 // purpose functions as they wouldn't have the right target features
3046 // enabled. For that reason we also forbid #[inline(always)] as it can't be
3048 if codegen_fn_attrs.target_features.len() > 0 {
3049 if codegen_fn_attrs.inline == InlineAttr::Always {
3050 if let Some(span) = inline_span {
3053 "cannot use `#[inline(always)]` with \
3054 `#[target_feature]`",
3060 if codegen_fn_attrs.flags.intersects(CodegenFnAttrFlags::NO_SANITIZE_ANY) {
3061 if codegen_fn_attrs.inline == InlineAttr::Always {
3062 if let (Some(no_sanitize_span), Some(inline_span)) = (no_sanitize_span, inline_span) {
3063 let hir_id = tcx.hir().as_local_hir_id(id).unwrap();
3064 tcx.struct_span_lint_hir(
3065 lint::builtin::INLINE_NO_SANITIZE,
3069 lint.build("`no_sanitize` will have no effect after inlining")
3070 .span_note(inline_span, "inlining requested here")
3078 // Weak lang items have the same semantics as "std internal" symbols in the
3079 // sense that they're preserved through all our LTO passes and only
3080 // strippable by the linker.
3082 // Additionally weak lang items have predetermined symbol names.
3083 if tcx.is_weak_lang_item(id) {
3084 codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL;
3086 if let Some(name) = lang_items::link_name(&attrs) {
3087 codegen_fn_attrs.export_name = Some(name);
3088 codegen_fn_attrs.link_name = Some(name);
3090 check_link_name_xor_ordinal(tcx, &codegen_fn_attrs, link_ordinal_span);
3092 // Internal symbols to the standard library all have no_mangle semantics in
3093 // that they have defined symbol names present in the function name. This
3094 // also applies to weak symbols where they all have known symbol names.
3095 if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL) {
3096 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_MANGLE;
3102 fn check_link_ordinal(tcx: TyCtxt<'_>, attr: &ast::Attribute) -> Option<usize> {
3103 use syntax::ast::{Lit, LitIntType, LitKind};
3104 let meta_item_list = attr.meta_item_list();
3105 let meta_item_list: Option<&[ast::NestedMetaItem]> = meta_item_list.as_ref().map(Vec::as_ref);
3106 let sole_meta_list = match meta_item_list {
3107 Some([item]) => item.literal(),
3110 if let Some(Lit { kind: LitKind::Int(ordinal, LitIntType::Unsuffixed), .. }) = sole_meta_list {
3111 if *ordinal <= std::usize::MAX as u128 {
3112 Some(*ordinal as usize)
3114 let msg = format!("ordinal value in `link_ordinal` is too large: `{}`", &ordinal);
3116 .struct_span_err(attr.span, &msg)
3117 .note("the value may not exceed `std::usize::MAX`")
3123 .struct_span_err(attr.span, "illegal ordinal format in `link_ordinal`")
3124 .note("an unsuffixed integer value, e.g., `1`, is expected")
3130 fn check_link_name_xor_ordinal(
3132 codegen_fn_attrs: &CodegenFnAttrs,
3133 inline_span: Option<Span>,
3135 if codegen_fn_attrs.link_name.is_none() || codegen_fn_attrs.link_ordinal.is_none() {
3138 let msg = "cannot use `#[link_name]` with `#[link_ordinal]`";
3139 if let Some(span) = inline_span {
3140 tcx.sess.span_err(span, msg);