1 //! "Collection" is the process of determining the type and other external
2 //! details of each item in Rust. Collection is specifically concerned
3 //! with *interprocedural* things -- for example, for a function
4 //! definition, collection will figure out the type and signature of the
5 //! function, but it will not visit the *body* of the function in any way,
6 //! nor examine type annotations on local variables (that's the job of
9 //! Collecting is ultimately defined by a bundle of queries that
10 //! inquire after various facts about the items in the crate (e.g.,
11 //! `type_of`, `generics_of`, `predicates_of`, etc). See the `provide` function
14 //! At present, however, we do run collection across all items in the
15 //! crate as a kind of pass. This should eventually be factored away.
17 use crate::astconv::{AstConv, Bounds};
18 use crate::constrained_type_params as ctp;
19 use crate::check::intrinsic::intrisic_operation_unsafety;
21 use crate::middle::lang_items::SizedTraitLangItem;
22 use crate::middle::resolve_lifetime as rl;
23 use crate::middle::weak_lang_items;
24 use rustc::mir::mono::Linkage;
25 use rustc::ty::query::Providers;
26 use rustc::ty::subst::Substs;
27 use rustc::ty::util::Discr;
28 use rustc::ty::util::IntTypeExt;
29 use rustc::ty::{self, AdtKind, ToPolyTraitRef, Ty, TyCtxt};
30 use rustc::ty::{ReprOptions, ToPredicate};
31 use rustc::util::captures::Captures;
32 use rustc::util::nodemap::FxHashMap;
33 use rustc_data_structures::sync::Lrc;
34 use rustc_target::spec::abi;
37 use syntax::ast::{Ident, MetaItemKind};
38 use syntax::attr::{InlineAttr, OptimizeAttr, list_contains_name, mark_used};
39 use syntax::source_map::Spanned;
40 use syntax::feature_gate;
41 use syntax::symbol::{keywords, Symbol};
42 use syntax_pos::{Span, DUMMY_SP};
44 use rustc::hir::def::{CtorKind, Def};
46 use rustc::hir::def_id::{DefId, LOCAL_CRATE};
47 use rustc::hir::intravisit::{self, NestedVisitorMap, Visitor};
48 use rustc::hir::GenericParamKind;
49 use rustc::hir::{self, CodegenFnAttrFlags, CodegenFnAttrs, Unsafety};
53 struct OnlySelfBounds(bool);
55 ///////////////////////////////////////////////////////////////////////////
58 pub fn collect_item_types<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
59 for &module in tcx.hir().krate().modules.keys() {
60 tcx.ensure().collect_mod_item_types(tcx.hir().local_def_id(module));
64 fn collect_mod_item_types<'tcx>(tcx: TyCtxt<'_, 'tcx, 'tcx>, module_def_id: DefId) {
65 tcx.hir().visit_item_likes_in_module(
67 &mut CollectItemTypesVisitor { tcx }.as_deep_visitor()
71 pub fn provide(providers: &mut Providers<'_>) {
72 *providers = Providers {
76 predicates_defined_on,
77 explicit_predicates_of,
79 type_param_predicates,
87 collect_mod_item_types,
92 ///////////////////////////////////////////////////////////////////////////
94 /// Context specific to some particular item. This is what implements
95 /// `AstConv`. It has information about the predicates that are defined
96 /// on the trait. Unfortunately, this predicate information is
97 /// available in various different forms at various points in the
98 /// process. So we can't just store a pointer to e.g., the AST or the
99 /// parsed ty form, we have to be more flexible. To this end, the
100 /// `ItemCtxt` is parameterized by a `DefId` that it uses to satisfy
101 /// `get_type_parameter_bounds` requests, drawing the information from
102 /// the AST (`hir::Generics`), recursively.
103 pub struct ItemCtxt<'a, 'tcx: 'a> {
104 tcx: TyCtxt<'a, 'tcx, 'tcx>,
108 ///////////////////////////////////////////////////////////////////////////
110 struct CollectItemTypesVisitor<'a, 'tcx: 'a> {
111 tcx: TyCtxt<'a, 'tcx, 'tcx>,
114 impl<'a, 'tcx> Visitor<'tcx> for CollectItemTypesVisitor<'a, 'tcx> {
115 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
116 NestedVisitorMap::OnlyBodies(&self.tcx.hir())
119 fn visit_item(&mut self, item: &'tcx hir::Item) {
120 convert_item(self.tcx, item.id);
121 intravisit::walk_item(self, item);
124 fn visit_generics(&mut self, generics: &'tcx hir::Generics) {
125 for param in &generics.params {
127 hir::GenericParamKind::Lifetime { .. } => {}
128 hir::GenericParamKind::Type {
131 let def_id = self.tcx.hir().local_def_id(param.id);
132 self.tcx.type_of(def_id);
134 hir::GenericParamKind::Type { .. } => {}
135 hir::GenericParamKind::Const { .. } => {
136 let def_id = self.tcx.hir().local_def_id(param.id);
137 self.tcx.type_of(def_id);
141 intravisit::walk_generics(self, generics);
144 fn visit_expr(&mut self, expr: &'tcx hir::Expr) {
145 if let hir::ExprKind::Closure(..) = expr.node {
146 let def_id = self.tcx.hir().local_def_id(expr.id);
147 self.tcx.generics_of(def_id);
148 self.tcx.type_of(def_id);
150 intravisit::walk_expr(self, expr);
153 fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem) {
154 convert_trait_item(self.tcx, trait_item.id);
155 intravisit::walk_trait_item(self, trait_item);
158 fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem) {
159 convert_impl_item(self.tcx, impl_item.id);
160 intravisit::walk_impl_item(self, impl_item);
164 ///////////////////////////////////////////////////////////////////////////
165 // Utility types and common code for the above passes.
167 impl<'a, 'tcx> ItemCtxt<'a, 'tcx> {
168 pub fn new(tcx: TyCtxt<'a, 'tcx, 'tcx>, item_def_id: DefId) -> ItemCtxt<'a, 'tcx> {
169 ItemCtxt { tcx, item_def_id }
173 impl<'a, 'tcx> ItemCtxt<'a, 'tcx> {
174 pub fn to_ty(&self, ast_ty: &hir::Ty) -> Ty<'tcx> {
175 AstConv::ast_ty_to_ty(self, ast_ty)
179 impl<'a, 'tcx> AstConv<'tcx, 'tcx> for ItemCtxt<'a, 'tcx> {
180 fn tcx<'b>(&'b self) -> TyCtxt<'b, 'tcx, 'tcx> {
184 fn get_type_parameter_bounds(&self, span: Span, def_id: DefId)
185 -> Lrc<ty::GenericPredicates<'tcx>> {
188 .type_param_predicates((self.item_def_id, def_id))
194 _def: Option<&ty::GenericParamDef>,
195 ) -> Option<ty::Region<'tcx>> {
199 fn ty_infer(&self, span: Span) -> Ty<'tcx> {
204 "the type placeholder `_` is not allowed within types on item signatures"
205 ).span_label(span, "not allowed in type signatures")
211 fn projected_ty_from_poly_trait_ref(
215 poly_trait_ref: ty::PolyTraitRef<'tcx>,
217 if let Some(trait_ref) = poly_trait_ref.no_bound_vars() {
218 self.tcx().mk_projection(item_def_id, trait_ref.substs)
220 // no late-bound regions, we can just ignore the binder
225 "cannot extract an associated type from a higher-ranked trait bound \
232 fn normalize_ty(&self, _span: Span, ty: Ty<'tcx>) -> Ty<'tcx> {
233 // types in item signatures are not normalized, to avoid undue
238 fn set_tainted_by_errors(&self) {
239 // no obvious place to track this, just let it go
242 fn record_ty(&self, _hir_id: hir::HirId, _ty: Ty<'tcx>, _span: Span) {
243 // no place to record types from signatures?
247 fn type_param_predicates<'a, 'tcx>(
248 tcx: TyCtxt<'a, 'tcx, 'tcx>,
249 (item_def_id, def_id): (DefId, DefId),
250 ) -> Lrc<ty::GenericPredicates<'tcx>> {
253 // In the AST, bounds can derive from two places. Either
254 // written inline like `<T : Foo>` or in a where clause like
257 let param_id = tcx.hir().as_local_node_id(def_id).unwrap();
258 let param_owner = tcx.hir().ty_param_owner(param_id);
259 let param_owner_def_id = tcx.hir().local_def_id(param_owner);
260 let generics = tcx.generics_of(param_owner_def_id);
261 let index = generics.param_def_id_to_index[&def_id];
262 let ty = tcx.mk_ty_param(index, tcx.hir().ty_param_name(param_id).as_interned_str());
264 // Don't look for bounds where the type parameter isn't in scope.
265 let parent = if item_def_id == param_owner_def_id {
268 tcx.generics_of(item_def_id).parent
271 let mut result = parent.map_or_else(
272 || Lrc::new(ty::GenericPredicates {
277 let icx = ItemCtxt::new(tcx, parent);
278 icx.get_type_parameter_bounds(DUMMY_SP, def_id)
282 let item_node_id = tcx.hir().as_local_node_id(item_def_id).unwrap();
283 let ast_generics = match tcx.hir().get(item_node_id) {
284 Node::TraitItem(item) => &item.generics,
286 Node::ImplItem(item) => &item.generics,
288 Node::Item(item) => {
290 ItemKind::Fn(.., ref generics, _)
291 | ItemKind::Impl(_, _, _, ref generics, ..)
292 | ItemKind::Ty(_, ref generics)
293 | ItemKind::Existential(ExistTy {
298 | ItemKind::Enum(_, ref generics)
299 | ItemKind::Struct(_, ref generics)
300 | ItemKind::Union(_, ref generics) => generics,
301 ItemKind::Trait(_, _, ref generics, ..) => {
302 // Implied `Self: Trait` and supertrait bounds.
303 if param_id == item_node_id {
304 let identity_trait_ref = ty::TraitRef::identity(tcx, item_def_id);
305 Lrc::make_mut(&mut result)
307 .push((identity_trait_ref.to_predicate(), item.span));
315 Node::ForeignItem(item) => match item.node {
316 ForeignItemKind::Fn(_, _, ref generics) => generics,
323 let icx = ItemCtxt::new(tcx, item_def_id);
324 Lrc::make_mut(&mut result)
326 .extend(icx.type_parameter_bounds_in_generics(ast_generics, param_id, ty,
327 OnlySelfBounds(true)));
331 impl<'a, 'tcx> ItemCtxt<'a, 'tcx> {
332 /// Finds bounds from `hir::Generics`. This requires scanning through the
333 /// AST. We do this to avoid having to convert *all* the bounds, which
334 /// would create artificial cycles. Instead we can only convert the
335 /// bounds for a type parameter `X` if `X::Foo` is used.
336 fn type_parameter_bounds_in_generics(
338 ast_generics: &hir::Generics,
339 param_id: ast::NodeId,
341 only_self_bounds: OnlySelfBounds,
342 ) -> Vec<(ty::Predicate<'tcx>, Span)> {
343 let from_ty_params = ast_generics
346 .filter_map(|param| match param.kind {
347 GenericParamKind::Type { .. } if param.id == param_id => Some(¶m.bounds),
350 .flat_map(|bounds| bounds.iter())
351 .flat_map(|b| predicates_from_bound(self, ty, b));
353 let from_where_clauses = ast_generics
357 .filter_map(|wp| match *wp {
358 hir::WherePredicate::BoundPredicate(ref bp) => Some(bp),
362 let bt = if is_param(self.tcx, &bp.bounded_ty, param_id) {
364 } else if !only_self_bounds.0 {
365 Some(self.to_ty(&bp.bounded_ty))
369 bp.bounds.iter().filter_map(move |b| bt.map(|bt| (bt, b)))
371 .flat_map(|(bt, b)| predicates_from_bound(self, bt, b));
373 from_ty_params.chain(from_where_clauses).collect()
377 /// Tests whether this is the AST for a reference to the type
378 /// parameter with ID `param_id`. We use this so as to avoid running
379 /// `ast_ty_to_ty`, because we want to avoid triggering an all-out
380 /// conversion of the type to avoid inducing unnecessary cycles.
381 fn is_param<'a, 'tcx>(
382 tcx: TyCtxt<'a, 'tcx, 'tcx>,
384 param_id: ast::NodeId,
386 if let hir::TyKind::Path(hir::QPath::Resolved(None, ref path)) = ast_ty.node {
388 Def::SelfTy(Some(def_id), None) | Def::TyParam(def_id) => {
389 def_id == tcx.hir().local_def_id(param_id)
398 fn convert_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, item_id: ast::NodeId) {
399 let it = tcx.hir().expect_item(item_id);
400 debug!("convert: item {} with id {}", it.ident, it.id);
401 let def_id = tcx.hir().local_def_id(item_id);
403 // These don't define types.
404 hir::ItemKind::ExternCrate(_)
405 | hir::ItemKind::Use(..)
406 | hir::ItemKind::Mod(_)
407 | hir::ItemKind::GlobalAsm(_) => {}
408 hir::ItemKind::ForeignMod(ref foreign_mod) => {
409 for item in &foreign_mod.items {
410 let def_id = tcx.hir().local_def_id(item.id);
411 tcx.generics_of(def_id);
413 tcx.predicates_of(def_id);
414 if let hir::ForeignItemKind::Fn(..) = item.node {
419 hir::ItemKind::Enum(ref enum_definition, _) => {
420 tcx.generics_of(def_id);
422 tcx.predicates_of(def_id);
423 convert_enum_variant_types(tcx, def_id, &enum_definition.variants);
425 hir::ItemKind::Impl(..) => {
426 tcx.generics_of(def_id);
428 tcx.impl_trait_ref(def_id);
429 tcx.predicates_of(def_id);
431 hir::ItemKind::Trait(..) => {
432 tcx.generics_of(def_id);
433 tcx.trait_def(def_id);
434 tcx.at(it.span).super_predicates_of(def_id);
435 tcx.predicates_of(def_id);
437 hir::ItemKind::TraitAlias(..) => {
438 tcx.generics_of(def_id);
439 tcx.at(it.span).super_predicates_of(def_id);
440 tcx.predicates_of(def_id);
442 hir::ItemKind::Struct(ref struct_def, _) | hir::ItemKind::Union(ref struct_def, _) => {
443 tcx.generics_of(def_id);
445 tcx.predicates_of(def_id);
447 for f in struct_def.fields() {
448 let def_id = tcx.hir().local_def_id(f.id);
449 tcx.generics_of(def_id);
451 tcx.predicates_of(def_id);
454 if !struct_def.is_struct() {
455 convert_variant_ctor(tcx, struct_def.id());
459 // Desugared from `impl Trait` -> visited by the function's return type
460 hir::ItemKind::Existential(hir::ExistTy {
461 impl_trait_fn: Some(_),
465 hir::ItemKind::Existential(..)
466 | hir::ItemKind::Ty(..)
467 | hir::ItemKind::Static(..)
468 | hir::ItemKind::Const(..)
469 | hir::ItemKind::Fn(..) => {
470 tcx.generics_of(def_id);
472 tcx.predicates_of(def_id);
473 if let hir::ItemKind::Fn(..) = it.node {
480 fn convert_trait_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, trait_item_id: ast::NodeId) {
481 let trait_item = tcx.hir().expect_trait_item(trait_item_id);
482 let def_id = tcx.hir().local_def_id(trait_item.id);
483 tcx.generics_of(def_id);
485 match trait_item.node {
486 hir::TraitItemKind::Const(..)
487 | hir::TraitItemKind::Type(_, Some(_))
488 | hir::TraitItemKind::Method(..) => {
490 if let hir::TraitItemKind::Method(..) = trait_item.node {
495 hir::TraitItemKind::Type(_, None) => {}
498 tcx.predicates_of(def_id);
501 fn convert_impl_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, impl_item_id: ast::NodeId) {
502 let def_id = tcx.hir().local_def_id(impl_item_id);
503 tcx.generics_of(def_id);
505 tcx.predicates_of(def_id);
506 if let hir::ImplItemKind::Method(..) = tcx.hir().expect_impl_item(impl_item_id).node {
511 fn convert_variant_ctor<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, ctor_id: ast::NodeId) {
512 let def_id = tcx.hir().local_def_id(ctor_id);
513 tcx.generics_of(def_id);
515 tcx.predicates_of(def_id);
518 fn convert_enum_variant_types<'a, 'tcx>(
519 tcx: TyCtxt<'a, 'tcx, 'tcx>,
521 variants: &[hir::Variant],
523 let def = tcx.adt_def(def_id);
524 let repr_type = def.repr.discr_type();
525 let initial = repr_type.initial_discriminant(tcx);
526 let mut prev_discr = None::<Discr<'tcx>>;
528 // fill the discriminant values and field types
529 for variant in variants {
530 let wrapped_discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
532 if let Some(ref e) = variant.node.disr_expr {
533 let expr_did = tcx.hir().local_def_id(e.id);
534 def.eval_explicit_discr(tcx, expr_did)
535 } else if let Some(discr) = repr_type.disr_incr(tcx, prev_discr) {
542 "enum discriminant overflowed"
545 format!("overflowed on value after {}", prev_discr.unwrap()),
547 "explicitly set `{} = {}` if that is desired outcome",
548 variant.node.ident, wrapped_discr
552 }.unwrap_or(wrapped_discr),
555 for f in variant.node.data.fields() {
556 let def_id = tcx.hir().local_def_id(f.id);
557 tcx.generics_of(def_id);
559 tcx.predicates_of(def_id);
562 // Convert the ctor, if any. This also registers the variant as
564 convert_variant_ctor(tcx, variant.node.data.id());
568 fn convert_variant<'a, 'tcx>(
569 tcx: TyCtxt<'a, 'tcx, 'tcx>,
572 discr: ty::VariantDiscr,
573 def: &hir::VariantData,
574 adt_kind: ty::AdtKind,
575 attribute_def_id: DefId
576 ) -> ty::VariantDef {
577 let mut seen_fields: FxHashMap<ast::Ident, Span> = Default::default();
578 let node_id = tcx.hir().as_local_node_id(did).unwrap();
583 let fid = tcx.hir().local_def_id(f.id);
584 let dup_span = seen_fields.get(&f.ident.modern()).cloned();
585 if let Some(prev_span) = dup_span {
590 "field `{}` is already declared",
592 ).span_label(f.span, "field already declared")
593 .span_label(prev_span, format!("`{}` first declared here", f.ident))
596 seen_fields.insert(f.ident.modern(), f.span);
602 vis: ty::Visibility::from_hir(&f.vis, node_id, tcx),
606 ty::VariantDef::new(tcx,
612 CtorKind::from_hir(def),
617 fn adt_def<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> &'tcx ty::AdtDef {
620 let node_id = tcx.hir().as_local_node_id(def_id).unwrap();
621 let item = match tcx.hir().get(node_id) {
622 Node::Item(item) => item,
626 let repr = ReprOptions::new(tcx, def_id);
627 let (kind, variants) = match item.node {
628 ItemKind::Enum(ref def, _) => {
629 let mut distance_from_explicit = 0;
635 let did = tcx.hir().local_def_id(v.node.data.id());
636 let discr = if let Some(ref e) = v.node.disr_expr {
637 distance_from_explicit = 0;
638 ty::VariantDiscr::Explicit(tcx.hir().local_def_id(e.id))
640 ty::VariantDiscr::Relative(distance_from_explicit)
642 distance_from_explicit += 1;
644 convert_variant(tcx, did, v.node.ident, discr, &v.node.data, AdtKind::Enum,
650 ItemKind::Struct(ref def, _) => {
651 // Use separate constructor id for unit/tuple structs and reuse did for braced structs.
652 let ctor_id = if !def.is_struct() {
653 Some(tcx.hir().local_def_id(def.id()))
659 std::iter::once(convert_variant(
661 ctor_id.unwrap_or(def_id),
663 ty::VariantDiscr::Relative(0),
670 ItemKind::Union(ref def, _) => (
672 std::iter::once(convert_variant(
676 ty::VariantDiscr::Relative(0),
684 tcx.alloc_adt_def(def_id, kind, variants, repr)
687 /// Ensures that the super-predicates of the trait with `DefId`
688 /// trait_def_id are converted and stored. This also ensures that
689 /// the transitive super-predicates are converted;
690 fn super_predicates_of<'a, 'tcx>(
691 tcx: TyCtxt<'a, 'tcx, 'tcx>,
693 ) -> Lrc<ty::GenericPredicates<'tcx>> {
694 debug!("super_predicates(trait_def_id={:?})", trait_def_id);
695 let trait_node_id = tcx.hir().as_local_node_id(trait_def_id).unwrap();
697 let item = match tcx.hir().get(trait_node_id) {
698 Node::Item(item) => item,
699 _ => bug!("trait_node_id {} is not an item", trait_node_id),
702 let (generics, bounds) = match item.node {
703 hir::ItemKind::Trait(.., ref generics, ref supertraits, _) => (generics, supertraits),
704 hir::ItemKind::TraitAlias(ref generics, ref supertraits) => (generics, supertraits),
705 _ => span_bug!(item.span, "super_predicates invoked on non-trait"),
708 let icx = ItemCtxt::new(tcx, trait_def_id);
710 // Convert the bounds that follow the colon, e.g., `Bar + Zed` in `trait Foo : Bar + Zed`.
711 let self_param_ty = tcx.mk_self_type();
712 let superbounds1 = compute_bounds(&icx, self_param_ty, bounds, SizedByDefault::No, item.span);
714 let superbounds1 = superbounds1.predicates(tcx, self_param_ty);
716 // Convert any explicit superbounds in the where clause,
717 // e.g., `trait Foo where Self : Bar`.
718 // In the case of trait aliases, however, we include all bounds in the where clause,
719 // so e.g., `trait Foo = where u32: PartialEq<Self>` would include `u32: PartialEq<Self>`
720 // as one of its "superpredicates".
721 let is_trait_alias = tcx.is_trait_alias(trait_def_id);
722 let superbounds2 = icx.type_parameter_bounds_in_generics(
723 generics, item.id, self_param_ty, OnlySelfBounds(!is_trait_alias));
725 // Combine the two lists to form the complete set of superbounds:
726 let superbounds: Vec<_> = superbounds1.into_iter().chain(superbounds2).collect();
728 // Now require that immediate supertraits are converted,
729 // which will, in turn, reach indirect supertraits.
730 for &(pred, span) in &superbounds {
731 debug!("superbound: {:?}", pred);
732 if let ty::Predicate::Trait(bound) = pred {
733 tcx.at(span).super_predicates_of(bound.def_id());
737 Lrc::new(ty::GenericPredicates {
739 predicates: superbounds,
743 fn trait_def<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> &'tcx ty::TraitDef {
744 let hir_id = tcx.hir().as_local_hir_id(def_id).unwrap();
745 let item = tcx.hir().expect_item_by_hir_id(hir_id);
747 let (is_auto, unsafety) = match item.node {
748 hir::ItemKind::Trait(is_auto, unsafety, ..) => (is_auto == hir::IsAuto::Yes, unsafety),
749 hir::ItemKind::TraitAlias(..) => (false, hir::Unsafety::Normal),
750 _ => span_bug!(item.span, "trait_def_of_item invoked on non-trait"),
753 let paren_sugar = tcx.has_attr(def_id, "rustc_paren_sugar");
754 if paren_sugar && !tcx.features().unboxed_closures {
755 let mut err = tcx.sess.struct_span_err(
757 "the `#[rustc_paren_sugar]` attribute is a temporary means of controlling \
758 which traits can use parenthetical notation",
762 "add `#![feature(unboxed_closures)]` to \
763 the crate attributes to use it"
768 let is_marker = tcx.has_attr(def_id, "marker");
769 let def_path_hash = tcx.def_path_hash(def_id);
770 let def = ty::TraitDef::new(def_id, unsafety, paren_sugar, is_auto, is_marker, def_path_hash);
771 tcx.alloc_trait_def(def)
774 fn has_late_bound_regions<'a, 'tcx>(
775 tcx: TyCtxt<'a, 'tcx, 'tcx>,
778 struct LateBoundRegionsDetector<'a, 'tcx: 'a> {
779 tcx: TyCtxt<'a, 'tcx, 'tcx>,
780 outer_index: ty::DebruijnIndex,
781 has_late_bound_regions: Option<Span>,
784 impl<'a, 'tcx> Visitor<'tcx> for LateBoundRegionsDetector<'a, 'tcx> {
785 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
786 NestedVisitorMap::None
789 fn visit_ty(&mut self, ty: &'tcx hir::Ty) {
790 if self.has_late_bound_regions.is_some() {
794 hir::TyKind::BareFn(..) => {
795 self.outer_index.shift_in(1);
796 intravisit::walk_ty(self, ty);
797 self.outer_index.shift_out(1);
799 _ => intravisit::walk_ty(self, ty),
803 fn visit_poly_trait_ref(
805 tr: &'tcx hir::PolyTraitRef,
806 m: hir::TraitBoundModifier,
808 if self.has_late_bound_regions.is_some() {
811 self.outer_index.shift_in(1);
812 intravisit::walk_poly_trait_ref(self, tr, m);
813 self.outer_index.shift_out(1);
816 fn visit_lifetime(&mut self, lt: &'tcx hir::Lifetime) {
817 if self.has_late_bound_regions.is_some() {
821 match self.tcx.named_region(lt.hir_id) {
822 Some(rl::Region::Static) | Some(rl::Region::EarlyBound(..)) => {}
823 Some(rl::Region::LateBound(debruijn, _, _))
824 | Some(rl::Region::LateBoundAnon(debruijn, _)) if debruijn < self.outer_index => {}
825 Some(rl::Region::LateBound(..))
826 | Some(rl::Region::LateBoundAnon(..))
827 | Some(rl::Region::Free(..))
829 self.has_late_bound_regions = Some(lt.span);
835 fn has_late_bound_regions<'a, 'tcx>(
836 tcx: TyCtxt<'a, 'tcx, 'tcx>,
837 generics: &'tcx hir::Generics,
838 decl: &'tcx hir::FnDecl,
840 let mut visitor = LateBoundRegionsDetector {
842 outer_index: ty::INNERMOST,
843 has_late_bound_regions: None,
845 for param in &generics.params {
846 if let GenericParamKind::Lifetime { .. } = param.kind {
847 if tcx.is_late_bound(param.hir_id) {
848 return Some(param.span);
852 visitor.visit_fn_decl(decl);
853 visitor.has_late_bound_regions
857 Node::TraitItem(item) => match item.node {
858 hir::TraitItemKind::Method(ref sig, _) => {
859 has_late_bound_regions(tcx, &item.generics, &sig.decl)
863 Node::ImplItem(item) => match item.node {
864 hir::ImplItemKind::Method(ref sig, _) => {
865 has_late_bound_regions(tcx, &item.generics, &sig.decl)
869 Node::ForeignItem(item) => match item.node {
870 hir::ForeignItemKind::Fn(ref fn_decl, _, ref generics) => {
871 has_late_bound_regions(tcx, generics, fn_decl)
875 Node::Item(item) => match item.node {
876 hir::ItemKind::Fn(ref fn_decl, .., ref generics, _) => {
877 has_late_bound_regions(tcx, generics, fn_decl)
885 fn generics_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> &'tcx ty::Generics {
888 let node_id = tcx.hir().as_local_node_id(def_id).unwrap();
890 let node = tcx.hir().get(node_id);
891 let parent_def_id = match node {
892 Node::ImplItem(_) | Node::TraitItem(_) | Node::Variant(_)
893 | Node::StructCtor(_) | Node::Field(_) => {
894 let parent_id = tcx.hir().get_parent(node_id);
895 Some(tcx.hir().local_def_id(parent_id))
897 Node::Expr(&hir::Expr {
898 node: hir::ExprKind::Closure(..),
900 }) => Some(tcx.closure_base_def_id(def_id)),
901 Node::Item(item) => match item.node {
902 ItemKind::Existential(hir::ExistTy { impl_trait_fn, .. }) => impl_trait_fn,
908 let mut opt_self = None;
909 let mut allow_defaults = false;
911 let no_generics = hir::Generics::empty();
912 let ast_generics = match node {
913 Node::TraitItem(item) => &item.generics,
915 Node::ImplItem(item) => &item.generics,
917 Node::Item(item) => {
919 ItemKind::Fn(.., ref generics, _) | ItemKind::Impl(_, _, _, ref generics, ..) => {
923 ItemKind::Ty(_, ref generics)
924 | ItemKind::Enum(_, ref generics)
925 | ItemKind::Struct(_, ref generics)
926 | ItemKind::Existential(hir::ExistTy { ref generics, .. })
927 | ItemKind::Union(_, ref generics) => {
928 allow_defaults = true;
932 ItemKind::Trait(_, _, ref generics, ..)
933 | ItemKind::TraitAlias(ref generics, ..) => {
934 // Add in the self type parameter.
936 // Something of a hack: use the node id for the trait, also as
937 // the node id for the Self type parameter.
938 let param_id = item.id;
940 opt_self = Some(ty::GenericParamDef {
942 name: keywords::SelfUpper.name().as_interned_str(),
943 def_id: tcx.hir().local_def_id(param_id),
944 pure_wrt_drop: false,
945 kind: ty::GenericParamDefKind::Type {
947 object_lifetime_default: rl::Set1::Empty,
952 allow_defaults = true;
960 Node::ForeignItem(item) => match item.node {
961 ForeignItemKind::Static(..) => &no_generics,
962 ForeignItemKind::Fn(_, _, ref generics) => generics,
963 ForeignItemKind::Type => &no_generics,
969 let has_self = opt_self.is_some();
970 let mut parent_has_self = false;
971 let mut own_start = has_self as u32;
972 let parent_count = parent_def_id.map_or(0, |def_id| {
973 let generics = tcx.generics_of(def_id);
974 assert_eq!(has_self, false);
975 parent_has_self = generics.has_self;
976 own_start = generics.count() as u32;
977 generics.parent_count + generics.params.len()
980 let mut params: Vec<_> = opt_self.into_iter().collect();
982 let early_lifetimes = early_bound_lifetimes_from_generics(tcx, ast_generics);
986 .map(|(i, param)| ty::GenericParamDef {
987 name: param.name.ident().as_interned_str(),
988 index: own_start + i as u32,
989 def_id: tcx.hir().local_def_id(param.id),
990 pure_wrt_drop: param.pure_wrt_drop,
991 kind: ty::GenericParamDefKind::Lifetime,
995 let hir_id = tcx.hir().node_to_hir_id(node_id);
996 let object_lifetime_defaults = tcx.object_lifetime_defaults(hir_id);
998 // Now create the real type parameters.
999 let type_start = own_start - has_self as u32 + params.len() as u32;
1005 .filter_map(|param| match param.kind {
1006 GenericParamKind::Type {
1011 if param.name.ident().name == keywords::SelfUpper.name() {
1014 "`Self` should not be the name of a regular parameter"
1018 if !allow_defaults && default.is_some() {
1019 if !tcx.features().default_type_parameter_fallback {
1021 lint::builtin::INVALID_TYPE_PARAM_DEFAULT,
1025 "defaults for type parameters are only allowed in \
1026 `struct`, `enum`, `type`, or `trait` definitions."
1032 let ty_param = ty::GenericParamDef {
1033 index: type_start + i as u32,
1034 name: param.name.ident().as_interned_str(),
1035 def_id: tcx.hir().local_def_id(param.id),
1036 pure_wrt_drop: param.pure_wrt_drop,
1037 kind: ty::GenericParamDefKind::Type {
1038 has_default: default.is_some(),
1039 object_lifetime_default: object_lifetime_defaults
1041 .map_or(rl::Set1::Empty, |o| o[i]),
1048 GenericParamKind::Const { .. } => {
1049 if param.name.ident().name == keywords::SelfUpper.name() {
1052 "`Self` should not be the name of a regular parameter",
1056 tcx.sess.struct_span_err(
1058 "const generics in any position are currently unsupported",
1060 tcx.sess.abort_if_errors();
1067 // provide junk type parameter defs - the only place that
1068 // cares about anything but the length is instantiation,
1069 // and we don't do that for closures.
1070 if let Node::Expr(&hir::Expr {
1071 node: hir::ExprKind::Closure(.., gen),
1075 let dummy_args = if gen.is_some() {
1076 &["<yield_ty>", "<return_ty>", "<witness>"][..]
1078 &["<closure_kind>", "<closure_signature>"][..]
1085 .map(|(i, &arg)| ty::GenericParamDef {
1086 index: type_start + i as u32,
1087 name: Symbol::intern(arg).as_interned_str(),
1089 pure_wrt_drop: false,
1090 kind: ty::GenericParamDefKind::Type {
1092 object_lifetime_default: rl::Set1::Empty,
1098 tcx.with_freevars(node_id, |fv| {
1099 params.extend(fv.iter().zip((dummy_args.len() as u32)..).map(|(_, i)| {
1100 ty::GenericParamDef {
1101 index: type_start + i,
1102 name: Symbol::intern("<upvar>").as_interned_str(),
1104 pure_wrt_drop: false,
1105 kind: ty::GenericParamDefKind::Type {
1107 object_lifetime_default: rl::Set1::Empty,
1115 let param_def_id_to_index = params
1117 .map(|param| (param.def_id, param.index))
1120 tcx.alloc_generics(ty::Generics {
1121 parent: parent_def_id,
1124 param_def_id_to_index,
1125 has_self: has_self || parent_has_self,
1126 has_late_bound_regions: has_late_bound_regions(tcx, node),
1130 fn report_assoc_ty_on_inherent_impl<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, span: Span) {
1135 "associated types are not yet supported in inherent impls (see #8995)"
1139 fn type_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Ty<'tcx> {
1142 let node_id = tcx.hir().as_local_node_id(def_id).unwrap();
1144 let icx = ItemCtxt::new(tcx, def_id);
1146 match tcx.hir().get(node_id) {
1147 Node::TraitItem(item) => match item.node {
1148 TraitItemKind::Method(..) => {
1149 let substs = Substs::identity_for_item(tcx, def_id);
1150 tcx.mk_fn_def(def_id, substs)
1152 TraitItemKind::Const(ref ty, _) | TraitItemKind::Type(_, Some(ref ty)) => icx.to_ty(ty),
1153 TraitItemKind::Type(_, None) => {
1154 span_bug!(item.span, "associated type missing default");
1158 Node::ImplItem(item) => match item.node {
1159 ImplItemKind::Method(..) => {
1160 let substs = Substs::identity_for_item(tcx, def_id);
1161 tcx.mk_fn_def(def_id, substs)
1163 ImplItemKind::Const(ref ty, _) => icx.to_ty(ty),
1164 ImplItemKind::Existential(_) => {
1166 .impl_trait_ref(tcx.hir().get_parent_did(node_id))
1169 report_assoc_ty_on_inherent_impl(tcx, item.span);
1172 find_existential_constraints(tcx, def_id)
1174 ImplItemKind::Type(ref ty) => {
1176 .impl_trait_ref(tcx.hir().get_parent_did(node_id))
1179 report_assoc_ty_on_inherent_impl(tcx, item.span);
1186 Node::Item(item) => {
1188 ItemKind::Static(ref t, ..)
1189 | ItemKind::Const(ref t, _)
1190 | ItemKind::Ty(ref t, _)
1191 | ItemKind::Impl(.., ref t, _) => icx.to_ty(t),
1192 ItemKind::Fn(..) => {
1193 let substs = Substs::identity_for_item(tcx, def_id);
1194 tcx.mk_fn_def(def_id, substs)
1196 ItemKind::Enum(..) | ItemKind::Struct(..) | ItemKind::Union(..) => {
1197 let def = tcx.adt_def(def_id);
1198 let substs = Substs::identity_for_item(tcx, def_id);
1199 tcx.mk_adt(def, substs)
1201 ItemKind::Existential(hir::ExistTy {
1202 impl_trait_fn: None,
1204 }) => find_existential_constraints(tcx, def_id),
1205 // existential types desugared from impl Trait
1206 ItemKind::Existential(hir::ExistTy {
1207 impl_trait_fn: Some(owner),
1210 tcx.typeck_tables_of(owner)
1211 .concrete_existential_types
1214 .unwrap_or_else(|| {
1215 // This can occur if some error in the
1216 // owner fn prevented us from populating
1217 // the `concrete_existential_types` table.
1218 tcx.sess.delay_span_bug(
1221 "owner {:?} has no existential type for {:?} in its tables",
1229 | ItemKind::TraitAlias(..)
1231 | ItemKind::ForeignMod(..)
1232 | ItemKind::GlobalAsm(..)
1233 | ItemKind::ExternCrate(..)
1234 | ItemKind::Use(..) => {
1237 "compute_type_of_item: unexpected item type: {:?}",
1244 Node::ForeignItem(foreign_item) => match foreign_item.node {
1245 ForeignItemKind::Fn(..) => {
1246 let substs = Substs::identity_for_item(tcx, def_id);
1247 tcx.mk_fn_def(def_id, substs)
1249 ForeignItemKind::Static(ref t, _) => icx.to_ty(t),
1250 ForeignItemKind::Type => tcx.mk_foreign(def_id),
1253 Node::StructCtor(&ref def)
1254 | Node::Variant(&Spanned {
1255 node: hir::VariantKind { data: ref def, .. },
1258 VariantData::Unit(..) | VariantData::Struct(..) => {
1259 tcx.type_of(tcx.hir().get_parent_did(node_id))
1261 VariantData::Tuple(..) => {
1262 let substs = Substs::identity_for_item(tcx, def_id);
1263 tcx.mk_fn_def(def_id, substs)
1267 Node::Field(field) => icx.to_ty(&field.ty),
1269 Node::Expr(&hir::Expr {
1270 node: hir::ExprKind::Closure(.., gen),
1274 let hir_id = tcx.hir().node_to_hir_id(node_id);
1275 return tcx.typeck_tables_of(def_id).node_type(hir_id);
1278 let substs = ty::ClosureSubsts {
1279 substs: Substs::identity_for_item(tcx, def_id),
1282 tcx.mk_closure(def_id, substs)
1285 Node::AnonConst(_) => match tcx.hir().get(tcx.hir().get_parent_node(node_id)) {
1287 node: hir::TyKind::Array(_, ref constant),
1290 | Node::Ty(&hir::Ty {
1291 node: hir::TyKind::Typeof(ref constant),
1294 | Node::Expr(&hir::Expr {
1295 node: ExprKind::Repeat(_, ref constant),
1297 }) if constant.id == node_id =>
1302 Node::Variant(&Spanned {
1305 disr_expr: Some(ref e),
1309 }) if e.id == node_id =>
1311 tcx.adt_def(tcx.hir().get_parent_did(node_id))
1318 bug!("unexpected const parent in type_of_def_id(): {:?}", x);
1322 Node::GenericParam(param) => match ¶m.kind {
1323 hir::GenericParamKind::Type {
1324 default: Some(ref ty),
1327 x => bug!("unexpected non-type Node::GenericParam: {:?}", x),
1331 bug!("unexpected sort of node in type_of_def_id(): {:?}", x);
1336 fn find_existential_constraints<'a, 'tcx>(
1337 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1342 struct ConstraintLocator<'a, 'tcx: 'a> {
1343 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1345 found: Option<(Span, ty::Ty<'tcx>)>,
1348 impl<'a, 'tcx> ConstraintLocator<'a, 'tcx> {
1349 fn check(&mut self, def_id: DefId) {
1350 trace!("checking {:?}", def_id);
1351 // don't try to check items that cannot possibly constrain the type
1352 if !self.tcx.has_typeck_tables(def_id) {
1353 trace!("no typeck tables for {:?}", def_id);
1358 .typeck_tables_of(def_id)
1359 .concrete_existential_types
1362 if let Some(ty) = ty {
1363 // FIXME(oli-obk): trace the actual span from inference to improve errors
1364 let span = self.tcx.def_span(def_id);
1365 if let Some((prev_span, prev_ty)) = self.found {
1367 // found different concrete types for the existential type
1368 let mut err = self.tcx.sess.struct_span_err(
1370 "defining existential type use differs from previous",
1372 err.span_note(prev_span, "previous use here");
1376 self.found = Some((span, ty));
1382 impl<'a, 'tcx> intravisit::Visitor<'tcx> for ConstraintLocator<'a, 'tcx> {
1383 fn nested_visit_map<'this>(&'this mut self) -> intravisit::NestedVisitorMap<'this, 'tcx> {
1384 intravisit::NestedVisitorMap::All(&self.tcx.hir())
1386 fn visit_item(&mut self, it: &'tcx Item) {
1387 let def_id = self.tcx.hir().local_def_id(it.id);
1388 // the existential type itself or its children are not within its reveal scope
1389 if def_id != self.def_id {
1391 intravisit::walk_item(self, it);
1394 fn visit_impl_item(&mut self, it: &'tcx ImplItem) {
1395 let def_id = self.tcx.hir().local_def_id(it.id);
1396 // the existential type itself or its children are not within its reveal scope
1397 if def_id != self.def_id {
1399 intravisit::walk_impl_item(self, it);
1402 fn visit_trait_item(&mut self, it: &'tcx TraitItem) {
1403 let def_id = self.tcx.hir().local_def_id(it.id);
1405 intravisit::walk_trait_item(self, it);
1409 let mut locator = ConstraintLocator {
1414 let node_id = tcx.hir().as_local_node_id(def_id).unwrap();
1415 let parent = tcx.hir().get_parent(node_id);
1417 trace!("parent_id: {:?}", parent);
1419 if parent == ast::CRATE_NODE_ID {
1420 intravisit::walk_crate(&mut locator, tcx.hir().krate());
1422 trace!("parent: {:?}", tcx.hir().get(parent));
1423 match tcx.hir().get(parent) {
1424 Node::Item(ref it) => intravisit::walk_item(&mut locator, it),
1425 Node::ImplItem(ref it) => intravisit::walk_impl_item(&mut locator, it),
1426 Node::TraitItem(ref it) => intravisit::walk_trait_item(&mut locator, it),
1428 "{:?} is not a valid parent of an existential type item",
1434 match locator.found {
1435 Some((_, ty)) => ty,
1437 let span = tcx.def_span(def_id);
1438 tcx.sess.span_err(span, "could not find defining uses");
1444 fn fn_sig<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> ty::PolyFnSig<'tcx> {
1446 use rustc::hir::Node::*;
1448 let node_id = tcx.hir().as_local_node_id(def_id).unwrap();
1450 let icx = ItemCtxt::new(tcx, def_id);
1452 match tcx.hir().get(node_id) {
1453 TraitItem(hir::TraitItem {
1454 node: TraitItemKind::Method(sig, _),
1457 | ImplItem(hir::ImplItem {
1458 node: ImplItemKind::Method(sig, _),
1460 }) => AstConv::ty_of_fn(&icx, sig.header.unsafety, sig.header.abi, &sig.decl),
1463 node: ItemKind::Fn(decl, header, _, _),
1465 }) => AstConv::ty_of_fn(&icx, header.unsafety, header.abi, decl),
1467 ForeignItem(&hir::ForeignItem {
1468 node: ForeignItemKind::Fn(ref fn_decl, _, _),
1471 let abi = tcx.hir().get_foreign_abi(node_id);
1472 compute_sig_of_foreign_fn_decl(tcx, def_id, fn_decl, abi)
1475 StructCtor(&VariantData::Tuple(ref fields, ..))
1476 | Variant(&Spanned {
1479 data: VariantData::Tuple(ref fields, ..),
1484 let ty = tcx.type_of(tcx.hir().get_parent_did(node_id));
1487 .map(|f| tcx.type_of(tcx.hir().local_def_id(f.id)));
1488 ty::Binder::bind(tcx.mk_fn_sig(
1492 hir::Unsafety::Normal,
1498 node: hir::ExprKind::Closure(..),
1501 // Closure signatures are not like other function
1502 // signatures and cannot be accessed through `fn_sig`. For
1503 // example, a closure signature excludes the `self`
1504 // argument. In any case they are embedded within the
1505 // closure type as part of the `ClosureSubsts`.
1508 // the signature of a closure, you should use the
1509 // `closure_sig` method on the `ClosureSubsts`:
1511 // closure_substs.closure_sig(def_id, tcx)
1513 // or, inside of an inference context, you can use
1515 // infcx.closure_sig(def_id, closure_substs)
1516 bug!("to get the signature of a closure, use `closure_sig()` not `fn_sig()`");
1520 bug!("unexpected sort of node in fn_sig(): {:?}", x);
1525 fn impl_trait_ref<'a, 'tcx>(
1526 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1528 ) -> Option<ty::TraitRef<'tcx>> {
1529 let icx = ItemCtxt::new(tcx, def_id);
1531 let hir_id = tcx.hir().as_local_hir_id(def_id).unwrap();
1532 match tcx.hir().expect_item_by_hir_id(hir_id).node {
1533 hir::ItemKind::Impl(.., ref opt_trait_ref, _, _) => {
1534 opt_trait_ref.as_ref().map(|ast_trait_ref| {
1535 let selfty = tcx.type_of(def_id);
1536 AstConv::instantiate_mono_trait_ref(&icx, ast_trait_ref, selfty)
1543 fn impl_polarity<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> hir::ImplPolarity {
1544 let hir_id = tcx.hir().as_local_hir_id(def_id).unwrap();
1545 match tcx.hir().expect_item_by_hir_id(hir_id).node {
1546 hir::ItemKind::Impl(_, polarity, ..) => polarity,
1547 ref item => bug!("impl_polarity: {:?} not an impl", item),
1551 // Is it marked with ?Sized
1552 fn is_unsized<'gcx: 'tcx, 'tcx>(
1553 astconv: &dyn AstConv<'gcx, 'tcx>,
1554 ast_bounds: &[hir::GenericBound],
1557 let tcx = astconv.tcx();
1559 // Try to find an unbound in bounds.
1560 let mut unbound = None;
1561 for ab in ast_bounds {
1562 if let &hir::GenericBound::Trait(ref ptr, hir::TraitBoundModifier::Maybe) = ab {
1563 if unbound.is_none() {
1564 unbound = Some(ptr.trait_ref.clone());
1570 "type parameter has more than one relaxed default \
1571 bound, only one is supported"
1577 let kind_id = tcx.lang_items().require(SizedTraitLangItem);
1580 // FIXME(#8559) currently requires the unbound to be built-in.
1581 if let Ok(kind_id) = kind_id {
1582 if tpb.path.def != Def::Trait(kind_id) {
1585 "default bound relaxed for a type parameter, but \
1586 this does nothing because the given bound is not \
1587 a default. Only `?Sized` is supported",
1592 _ if kind_id.is_ok() => {
1595 // No lang item for Sized, so we can't add it as a bound.
1602 /// Returns the early-bound lifetimes declared in this generics
1603 /// listing. For anything other than fns/methods, this is just all
1604 /// the lifetimes that are declared. For fns or methods, we have to
1605 /// screen out those that do not appear in any where-clauses etc using
1606 /// `resolve_lifetime::early_bound_lifetimes`.
1607 fn early_bound_lifetimes_from_generics<'a, 'tcx>(
1608 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1609 generics: &'a hir::Generics,
1610 ) -> impl Iterator<Item = &'a hir::GenericParam> + Captures<'tcx> {
1614 .filter(move |param| match param.kind {
1615 GenericParamKind::Lifetime { .. } => {
1616 let hir_id = tcx.hir().node_to_hir_id(param.id);
1617 !tcx.is_late_bound(hir_id)
1623 /// Returns a list of type predicates for the definition with ID `def_id`, including inferred
1624 /// lifetime constraints. This includes all predicates returned by `explicit_predicates_of`, plus
1625 /// inferred constraints concerning which regions outlive other regions.
1626 fn predicates_defined_on<'a, 'tcx>(
1627 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1629 ) -> Lrc<ty::GenericPredicates<'tcx>> {
1630 debug!("predicates_defined_on({:?})", def_id);
1631 let mut result = tcx.explicit_predicates_of(def_id);
1633 "predicates_defined_on: explicit_predicates_of({:?}) = {:?}",
1637 let inferred_outlives = tcx.inferred_outlives_of(def_id);
1638 if !inferred_outlives.is_empty() {
1639 let span = tcx.def_span(def_id);
1641 "predicates_defined_on: inferred_outlives_of({:?}) = {:?}",
1645 Lrc::make_mut(&mut result)
1647 .extend(inferred_outlives.iter().map(|&p| (p, span)));
1649 debug!("predicates_defined_on({:?}) = {:?}", def_id, result);
1653 /// Returns a list of all type predicates (explicit and implicit) for the definition with
1654 /// ID `def_id`. This includes all predicates returned by `predicates_defined_on`, plus
1655 /// `Self: Trait` predicates for traits.
1656 fn predicates_of<'a, 'tcx>(
1657 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1659 ) -> Lrc<ty::GenericPredicates<'tcx>> {
1660 let mut result = tcx.predicates_defined_on(def_id);
1662 if tcx.is_trait(def_id) {
1663 // For traits, add `Self: Trait` predicate. This is
1664 // not part of the predicates that a user writes, but it
1665 // is something that one must prove in order to invoke a
1666 // method or project an associated type.
1668 // In the chalk setup, this predicate is not part of the
1669 // "predicates" for a trait item. But it is useful in
1670 // rustc because if you directly (e.g.) invoke a trait
1671 // method like `Trait::method(...)`, you must naturally
1672 // prove that the trait applies to the types that were
1673 // used, and adding the predicate into this list ensures
1674 // that this is done.
1675 let span = tcx.def_span(def_id);
1676 Lrc::make_mut(&mut result)
1678 .push((ty::TraitRef::identity(tcx, def_id).to_predicate(), span));
1680 debug!("predicates_of(def_id={:?}) = {:?}", def_id, result);
1684 /// Returns a list of user-specified type predicates for the definition with ID `def_id`.
1685 /// N.B., this does not include any implied/inferred constraints.
1686 fn explicit_predicates_of<'a, 'tcx>(
1687 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1689 ) -> Lrc<ty::GenericPredicates<'tcx>> {
1691 use rustc_data_structures::fx::FxHashSet;
1693 debug!("explicit_predicates_of(def_id={:?})", def_id);
1695 /// A data structure with unique elements, which preserves order of insertion.
1696 /// Preserving the order of insertion is important here so as not to break
1697 /// compile-fail UI tests.
1698 struct UniquePredicates<'tcx> {
1699 predicates: Vec<(ty::Predicate<'tcx>, Span)>,
1700 uniques: FxHashSet<(ty::Predicate<'tcx>, Span)>,
1703 impl<'tcx> UniquePredicates<'tcx> {
1707 uniques: FxHashSet::default(),
1711 fn push(&mut self, value: (ty::Predicate<'tcx>, Span)) {
1712 if self.uniques.insert(value) {
1713 self.predicates.push(value);
1717 fn extend<I: IntoIterator<Item = (ty::Predicate<'tcx>, Span)>>(&mut self, iter: I) {
1724 let node_id = tcx.hir().as_local_node_id(def_id).unwrap();
1725 let node = tcx.hir().get(node_id);
1727 let mut is_trait = None;
1728 let mut is_default_impl_trait = None;
1730 let icx = ItemCtxt::new(tcx, def_id);
1731 let no_generics = hir::Generics::empty();
1732 let empty_trait_items = HirVec::new();
1734 let mut predicates = UniquePredicates::new();
1736 let ast_generics = match node {
1737 Node::TraitItem(item) => &item.generics,
1739 Node::ImplItem(item) => match item.node {
1740 ImplItemKind::Existential(ref bounds) => {
1741 let substs = Substs::identity_for_item(tcx, def_id);
1742 let opaque_ty = tcx.mk_opaque(def_id, substs);
1744 // Collect the bounds, i.e., the `A+B+'c` in `impl A+B+'c`.
1745 let bounds = compute_bounds(
1749 SizedByDefault::Yes,
1750 tcx.def_span(def_id),
1753 predicates.extend(bounds.predicates(tcx, opaque_ty));
1756 _ => &item.generics,
1759 Node::Item(item) => {
1761 ItemKind::Impl(_, _, defaultness, ref generics, ..) => {
1762 if defaultness.is_default() {
1763 is_default_impl_trait = tcx.impl_trait_ref(def_id);
1767 ItemKind::Fn(.., ref generics, _)
1768 | ItemKind::Ty(_, ref generics)
1769 | ItemKind::Enum(_, ref generics)
1770 | ItemKind::Struct(_, ref generics)
1771 | ItemKind::Union(_, ref generics) => generics,
1773 ItemKind::Trait(_, _, ref generics, .., ref items) => {
1774 is_trait = Some((ty::TraitRef::identity(tcx, def_id), items));
1777 ItemKind::TraitAlias(ref generics, _) => {
1778 is_trait = Some((ty::TraitRef::identity(tcx, def_id), &empty_trait_items));
1781 ItemKind::Existential(ExistTy {
1786 let substs = Substs::identity_for_item(tcx, def_id);
1787 let opaque_ty = tcx.mk_opaque(def_id, substs);
1789 // Collect the bounds, i.e., the `A+B+'c` in `impl A+B+'c`.
1790 let bounds = compute_bounds(
1794 SizedByDefault::Yes,
1795 tcx.def_span(def_id),
1798 if impl_trait_fn.is_some() {
1800 return Lrc::new(ty::GenericPredicates {
1802 predicates: bounds.predicates(tcx, opaque_ty),
1805 // named existential types
1806 predicates.extend(bounds.predicates(tcx, opaque_ty));
1815 Node::ForeignItem(item) => match item.node {
1816 ForeignItemKind::Static(..) => &no_generics,
1817 ForeignItemKind::Fn(_, _, ref generics) => generics,
1818 ForeignItemKind::Type => &no_generics,
1824 let generics = tcx.generics_of(def_id);
1825 let parent_count = generics.parent_count as u32;
1826 let has_own_self = generics.has_self && parent_count == 0;
1828 // Below we'll consider the bounds on the type parameters (including `Self`)
1829 // and the explicit where-clauses, but to get the full set of predicates
1830 // on a trait we need to add in the supertrait bounds and bounds found on
1831 // associated types.
1832 if let Some((_trait_ref, _)) = is_trait {
1833 predicates.extend(tcx.super_predicates_of(def_id).predicates.iter().cloned());
1836 // In default impls, we can assume that the self type implements
1837 // the trait. So in:
1839 // default impl Foo for Bar { .. }
1841 // we add a default where clause `Foo: Bar`. We do a similar thing for traits
1842 // (see below). Recall that a default impl is not itself an impl, but rather a
1843 // set of defaults that can be incorporated into another impl.
1844 if let Some(trait_ref) = is_default_impl_trait {
1845 predicates.push((trait_ref.to_poly_trait_ref().to_predicate(), tcx.def_span(def_id)));
1848 // Collect the region predicates that were declared inline as
1849 // well. In the case of parameters declared on a fn or method, we
1850 // have to be careful to only iterate over early-bound regions.
1851 let mut index = parent_count + has_own_self as u32;
1852 for param in early_bound_lifetimes_from_generics(tcx, ast_generics) {
1853 let region = tcx.mk_region(ty::ReEarlyBound(ty::EarlyBoundRegion {
1854 def_id: tcx.hir().local_def_id(param.id),
1856 name: param.name.ident().as_interned_str(),
1861 GenericParamKind::Lifetime { .. } => {
1862 param.bounds.iter().for_each(|bound| match bound {
1863 hir::GenericBound::Outlives(lt) => {
1864 let bound = AstConv::ast_region_to_region(&icx, <, None);
1865 let outlives = ty::Binder::bind(ty::OutlivesPredicate(region, bound));
1866 predicates.push((outlives.to_predicate(), lt.span));
1875 // Collect the predicates that were written inline by the user on each
1876 // type parameter (e.g., `<T:Foo>`).
1877 for param in &ast_generics.params {
1878 if let GenericParamKind::Type { .. } = param.kind {
1879 let name = param.name.ident().as_interned_str();
1880 let param_ty = ty::ParamTy::new(index, name).to_ty(tcx);
1883 let sized = SizedByDefault::Yes;
1884 let bounds = compute_bounds(&icx, param_ty, ¶m.bounds, sized, param.span);
1885 predicates.extend(bounds.predicates(tcx, param_ty));
1889 // Add in the bounds that appear in the where-clause
1890 let where_clause = &ast_generics.where_clause;
1891 for predicate in &where_clause.predicates {
1893 &hir::WherePredicate::BoundPredicate(ref bound_pred) => {
1894 let ty = icx.to_ty(&bound_pred.bounded_ty);
1896 // Keep the type around in a dummy predicate, in case of no bounds.
1897 // That way, `where Ty:` is not a complete noop (see #53696) and `Ty`
1898 // is still checked for WF.
1899 if bound_pred.bounds.is_empty() {
1900 if let ty::Param(_) = ty.sty {
1901 // This is a `where T:`, which can be in the HIR from the
1902 // transformation that moves `?Sized` to `T`'s declaration.
1903 // We can skip the predicate because type parameters are
1904 // trivially WF, but also we *should*, to avoid exposing
1905 // users who never wrote `where Type:,` themselves, to
1906 // compiler/tooling bugs from not handling WF predicates.
1908 let span = bound_pred.bounded_ty.span;
1909 let predicate = ty::OutlivesPredicate(ty, tcx.mk_region(ty::ReEmpty));
1911 (ty::Predicate::TypeOutlives(ty::Binder::dummy(predicate)), span)
1916 for bound in bound_pred.bounds.iter() {
1918 &hir::GenericBound::Trait(ref poly_trait_ref, _) => {
1919 let mut projections = Vec::new();
1921 let (trait_ref, _) = AstConv::instantiate_poly_trait_ref(
1929 iter::once((trait_ref.to_predicate(), poly_trait_ref.span)).chain(
1930 projections.iter().map(|&(p, span)| (p.to_predicate(), span)
1934 &hir::GenericBound::Outlives(ref lifetime) => {
1935 let region = AstConv::ast_region_to_region(&icx, lifetime, None);
1936 let pred = ty::Binder::bind(ty::OutlivesPredicate(ty, region));
1937 predicates.push((ty::Predicate::TypeOutlives(pred), lifetime.span))
1943 &hir::WherePredicate::RegionPredicate(ref region_pred) => {
1944 let r1 = AstConv::ast_region_to_region(&icx, ®ion_pred.lifetime, None);
1945 predicates.extend(region_pred.bounds.iter().map(|bound| {
1946 let (r2, span) = match bound {
1947 hir::GenericBound::Outlives(lt) => {
1948 (AstConv::ast_region_to_region(&icx, lt, None), lt.span)
1952 let pred = ty::Binder::bind(ty::OutlivesPredicate(r1, r2));
1954 (ty::Predicate::RegionOutlives(pred), span)
1958 &hir::WherePredicate::EqPredicate(..) => {
1964 // Add predicates from associated type bounds.
1965 if let Some((self_trait_ref, trait_items)) = is_trait {
1966 predicates.extend(trait_items.iter().flat_map(|trait_item_ref| {
1967 let trait_item = tcx.hir().trait_item(trait_item_ref.id);
1968 let bounds = match trait_item.node {
1969 hir::TraitItemKind::Type(ref bounds, _) => bounds,
1970 _ => return vec![].into_iter()
1974 tcx.mk_projection(tcx.hir().local_def_id(trait_item.id), self_trait_ref.substs);
1976 let bounds = compute_bounds(
1977 &ItemCtxt::new(tcx, def_id),
1980 SizedByDefault::Yes,
1984 bounds.predicates(tcx, assoc_ty).into_iter()
1988 let mut predicates = predicates.predicates;
1990 // Subtle: before we store the predicates into the tcx, we
1991 // sort them so that predicates like `T: Foo<Item=U>` come
1992 // before uses of `U`. This avoids false ambiguity errors
1993 // in trait checking. See `setup_constraining_predicates`
1995 if let Node::Item(&Item {
1996 node: ItemKind::Impl(..),
2000 let self_ty = tcx.type_of(def_id);
2001 let trait_ref = tcx.impl_trait_ref(def_id);
2002 ctp::setup_constraining_predicates(
2006 &mut ctp::parameters_for_impl(self_ty, trait_ref),
2010 let result = Lrc::new(ty::GenericPredicates {
2011 parent: generics.parent,
2014 debug!("explicit_predicates_of(def_id={:?}) = {:?}", def_id, result);
2018 pub enum SizedByDefault {
2023 /// Translate the AST's notion of ty param bounds (which are an enum consisting of a newtyped `Ty`
2024 /// or a region) to ty's notion of ty param bounds, which can either be user-defined traits, or the
2025 /// built-in trait `Send`.
2026 pub fn compute_bounds<'gcx: 'tcx, 'tcx>(
2027 astconv: &dyn AstConv<'gcx, 'tcx>,
2029 ast_bounds: &[hir::GenericBound],
2030 sized_by_default: SizedByDefault,
2033 let mut region_bounds = Vec::new();
2034 let mut trait_bounds = Vec::new();
2036 for ast_bound in ast_bounds {
2038 hir::GenericBound::Trait(ref b, hir::TraitBoundModifier::None) => trait_bounds.push(b),
2039 hir::GenericBound::Trait(_, hir::TraitBoundModifier::Maybe) => {}
2040 hir::GenericBound::Outlives(ref l) => region_bounds.push(l),
2044 let mut projection_bounds = Vec::new();
2046 let mut trait_bounds: Vec<_> = trait_bounds.iter().map(|&bound| {
2047 let (poly_trait_ref, _) = astconv.instantiate_poly_trait_ref(
2050 &mut projection_bounds,
2052 (poly_trait_ref, bound.span)
2055 let region_bounds = region_bounds
2057 .map(|r| (astconv.ast_region_to_region(r, None), r.span))
2060 trait_bounds.sort_by_key(|(t, _)| t.def_id());
2062 let implicitly_sized = if let SizedByDefault::Yes = sized_by_default {
2063 if !is_unsized(astconv, ast_bounds, span) {
2080 /// Converts a specific `GenericBound` from the AST into a set of
2081 /// predicates that apply to the self type. A vector is returned
2082 /// because this can be anywhere from zero predicates (`T: ?Sized` adds no
2083 /// predicates) to one (`T: Foo`) to many (`T: Bar<X=i32>` adds `T: Bar`
2084 /// and `<T as Bar>::X == i32`).
2085 fn predicates_from_bound<'tcx>(
2086 astconv: &dyn AstConv<'tcx, 'tcx>,
2088 bound: &hir::GenericBound,
2089 ) -> Vec<(ty::Predicate<'tcx>, Span)> {
2091 hir::GenericBound::Trait(ref tr, hir::TraitBoundModifier::None) => {
2092 let mut projections = Vec::new();
2093 let (pred, _) = astconv.instantiate_poly_trait_ref(tr, param_ty, &mut projections);
2094 iter::once((pred.to_predicate(), tr.span)).chain(
2097 .map(|(p, span)| (p.to_predicate(), span))
2100 hir::GenericBound::Outlives(ref lifetime) => {
2101 let region = astconv.ast_region_to_region(lifetime, None);
2102 let pred = ty::Binder::bind(ty::OutlivesPredicate(param_ty, region));
2103 vec![(ty::Predicate::TypeOutlives(pred), lifetime.span)]
2105 hir::GenericBound::Trait(_, hir::TraitBoundModifier::Maybe) => vec![],
2109 fn compute_sig_of_foreign_fn_decl<'a, 'tcx>(
2110 tcx: TyCtxt<'a, 'tcx, 'tcx>,
2114 ) -> ty::PolyFnSig<'tcx> {
2115 let unsafety = if abi == abi::Abi::RustIntrinsic {
2116 intrisic_operation_unsafety(&*tcx.item_name(def_id).as_str())
2118 hir::Unsafety::Unsafe
2120 let fty = AstConv::ty_of_fn(&ItemCtxt::new(tcx, def_id), unsafety, abi, decl);
2122 // feature gate SIMD types in FFI, since I (huonw) am not sure the
2123 // ABIs are handled at all correctly.
2124 if abi != abi::Abi::RustIntrinsic
2125 && abi != abi::Abi::PlatformIntrinsic
2126 && !tcx.features().simd_ffi
2128 let check = |ast_ty: &hir::Ty, ty: Ty| {
2134 "use of SIMD type `{}` in FFI is highly experimental and \
2135 may result in invalid code",
2136 tcx.hir().node_to_pretty_string(ast_ty.id)
2139 .help("add #![feature(simd_ffi)] to the crate attributes to enable")
2143 for (input, ty) in decl.inputs.iter().zip(*fty.inputs().skip_binder()) {
2146 if let hir::Return(ref ty) = decl.output {
2147 check(&ty, *fty.output().skip_binder())
2154 fn is_foreign_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> bool {
2155 match tcx.hir().get_if_local(def_id) {
2156 Some(Node::ForeignItem(..)) => true,
2158 _ => bug!("is_foreign_item applied to non-local def-id {:?}", def_id),
2162 fn from_target_feature(
2165 attr: &ast::Attribute,
2166 whitelist: &FxHashMap<String, Option<String>>,
2167 target_features: &mut Vec<Symbol>,
2169 let list = match attr.meta_item_list() {
2173 let rust_features = tcx.features();
2175 // Only `enable = ...` is accepted in the meta item list
2176 if !item.check_name("enable") {
2177 let msg = "#[target_feature(..)] only accepts sub-keys of `enable` \
2179 tcx.sess.span_err(item.span, &msg);
2183 // Must be of the form `enable = "..."` ( a string)
2184 let value = match item.value_str() {
2185 Some(value) => value,
2187 let msg = "#[target_feature] attribute must be of the form \
2188 #[target_feature(enable = \"..\")]";
2189 tcx.sess.span_err(item.span, &msg);
2194 // We allow comma separation to enable multiple features
2195 target_features.extend(value.as_str().split(',').filter_map(|feature| {
2196 // Only allow whitelisted features per platform
2197 let feature_gate = match whitelist.get(feature) {
2201 "the feature named `{}` is not valid for \
2205 let mut err = tcx.sess.struct_span_err(item.span, &msg);
2207 if feature.starts_with("+") {
2208 let valid = whitelist.contains_key(&feature[1..]);
2210 err.help("consider removing the leading `+` in the feature name");
2218 // Only allow features whose feature gates have been enabled
2219 let allowed = match feature_gate.as_ref().map(|s| &**s) {
2220 Some("arm_target_feature") => rust_features.arm_target_feature,
2221 Some("aarch64_target_feature") => rust_features.aarch64_target_feature,
2222 Some("hexagon_target_feature") => rust_features.hexagon_target_feature,
2223 Some("powerpc_target_feature") => rust_features.powerpc_target_feature,
2224 Some("mips_target_feature") => rust_features.mips_target_feature,
2225 Some("avx512_target_feature") => rust_features.avx512_target_feature,
2226 Some("mmx_target_feature") => rust_features.mmx_target_feature,
2227 Some("sse4a_target_feature") => rust_features.sse4a_target_feature,
2228 Some("tbm_target_feature") => rust_features.tbm_target_feature,
2229 Some("wasm_target_feature") => rust_features.wasm_target_feature,
2230 Some("cmpxchg16b_target_feature") => rust_features.cmpxchg16b_target_feature,
2231 Some("adx_target_feature") => rust_features.adx_target_feature,
2232 Some("movbe_target_feature") => rust_features.movbe_target_feature,
2233 Some(name) => bug!("unknown target feature gate {}", name),
2236 if !allowed && id.is_local() {
2237 feature_gate::emit_feature_err(
2238 &tcx.sess.parse_sess,
2239 feature_gate.as_ref().unwrap(),
2241 feature_gate::GateIssue::Language,
2242 &format!("the target feature `{}` is currently unstable", feature),
2245 Some(Symbol::intern(feature))
2250 fn linkage_by_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId, name: &str) -> Linkage {
2251 use rustc::mir::mono::Linkage::*;
2253 // Use the names from src/llvm/docs/LangRef.rst here. Most types are only
2254 // applicable to variable declarations and may not really make sense for
2255 // Rust code in the first place but whitelist them anyway and trust that
2256 // the user knows what s/he's doing. Who knows, unanticipated use cases
2257 // may pop up in the future.
2259 // ghost, dllimport, dllexport and linkonce_odr_autohide are not supported
2260 // and don't have to be, LLVM treats them as no-ops.
2262 "appending" => Appending,
2263 "available_externally" => AvailableExternally,
2265 "extern_weak" => ExternalWeak,
2266 "external" => External,
2267 "internal" => Internal,
2268 "linkonce" => LinkOnceAny,
2269 "linkonce_odr" => LinkOnceODR,
2270 "private" => Private,
2272 "weak_odr" => WeakODR,
2274 let span = tcx.hir().span_if_local(def_id);
2275 if let Some(span) = span {
2276 tcx.sess.span_fatal(span, "invalid linkage specified")
2279 .fatal(&format!("invalid linkage specified: {}", name))
2285 fn codegen_fn_attrs<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, id: DefId) -> CodegenFnAttrs {
2286 let attrs = tcx.get_attrs(id);
2288 let mut codegen_fn_attrs = CodegenFnAttrs::new();
2290 let whitelist = tcx.target_features_whitelist(LOCAL_CRATE);
2292 let mut inline_span = None;
2293 for attr in attrs.iter() {
2294 if attr.check_name("cold") {
2295 codegen_fn_attrs.flags |= CodegenFnAttrFlags::COLD;
2296 } else if attr.check_name("allocator") {
2297 codegen_fn_attrs.flags |= CodegenFnAttrFlags::ALLOCATOR;
2298 } else if attr.check_name("unwind") {
2299 codegen_fn_attrs.flags |= CodegenFnAttrFlags::UNWIND;
2300 } else if attr.check_name("rustc_allocator_nounwind") {
2301 codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_ALLOCATOR_NOUNWIND;
2302 } else if attr.check_name("naked") {
2303 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NAKED;
2304 } else if attr.check_name("no_mangle") {
2305 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_MANGLE;
2306 } else if attr.check_name("rustc_std_internal_symbol") {
2307 codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL;
2308 } else if attr.check_name("no_debug") {
2309 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_DEBUG;
2310 } else if attr.check_name("used") {
2311 codegen_fn_attrs.flags |= CodegenFnAttrFlags::USED;
2312 } else if attr.check_name("thread_local") {
2313 codegen_fn_attrs.flags |= CodegenFnAttrFlags::THREAD_LOCAL;
2314 } else if attr.check_name("export_name") {
2315 if let Some(s) = attr.value_str() {
2316 if s.as_str().contains("\0") {
2317 // `#[export_name = ...]` will be converted to a null-terminated string,
2318 // so it may not contain any null characters.
2323 "`export_name` may not contain null characters"
2326 codegen_fn_attrs.export_name = Some(s);
2328 } else if attr.check_name("target_feature") {
2329 if tcx.fn_sig(id).unsafety() == Unsafety::Normal {
2330 let msg = "#[target_feature(..)] can only be applied to \
2332 tcx.sess.span_err(attr.span, msg);
2334 from_target_feature(
2339 &mut codegen_fn_attrs.target_features,
2341 } else if attr.check_name("linkage") {
2342 if let Some(val) = attr.value_str() {
2343 codegen_fn_attrs.linkage = Some(linkage_by_name(tcx, id, &val.as_str()));
2345 } else if attr.check_name("link_section") {
2346 if let Some(val) = attr.value_str() {
2347 if val.as_str().bytes().any(|b| b == 0) {
2349 "illegal null byte in link_section \
2353 tcx.sess.span_err(attr.span, &msg);
2355 codegen_fn_attrs.link_section = Some(val);
2358 } else if attr.check_name("link_name") {
2359 codegen_fn_attrs.link_name = attr.value_str();
2363 codegen_fn_attrs.inline = attrs.iter().fold(InlineAttr::None, |ia, attr| {
2364 if attr.path != "inline" {
2367 match attr.meta().map(|i| i.node) {
2368 Some(MetaItemKind::Word) => {
2372 Some(MetaItemKind::List(ref items)) => {
2374 inline_span = Some(attr.span);
2375 if items.len() != 1 {
2377 tcx.sess.diagnostic(),
2380 "expected one argument"
2383 } else if list_contains_name(&items[..], "always") {
2385 } else if list_contains_name(&items[..], "never") {
2389 tcx.sess.diagnostic(),
2398 Some(MetaItemKind::NameValue(_)) => ia,
2403 codegen_fn_attrs.optimize = attrs.iter().fold(OptimizeAttr::None, |ia, attr| {
2404 if attr.path != "optimize" {
2407 let err = |sp, s| span_err!(tcx.sess.diagnostic(), sp, E0722, "{}", s);
2408 match attr.meta().map(|i| i.node) {
2409 Some(MetaItemKind::Word) => {
2410 err(attr.span, "expected one argument");
2413 Some(MetaItemKind::List(ref items)) => {
2415 inline_span = Some(attr.span);
2416 if items.len() != 1 {
2417 err(attr.span, "expected one argument");
2419 } else if list_contains_name(&items[..], "size") {
2421 } else if list_contains_name(&items[..], "speed") {
2424 err(items[0].span, "invalid argument");
2428 Some(MetaItemKind::NameValue(_)) => ia,
2433 // If a function uses #[target_feature] it can't be inlined into general
2434 // purpose functions as they wouldn't have the right target features
2435 // enabled. For that reason we also forbid #[inline(always)] as it can't be
2437 if codegen_fn_attrs.target_features.len() > 0 {
2438 if codegen_fn_attrs.inline == InlineAttr::Always {
2439 if let Some(span) = inline_span {
2442 "cannot use #[inline(always)] with \
2449 // Weak lang items have the same semantics as "std internal" symbols in the
2450 // sense that they're preserved through all our LTO passes and only
2451 // strippable by the linker.
2453 // Additionally weak lang items have predetermined symbol names.
2454 if tcx.is_weak_lang_item(id) {
2455 codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL;
2457 if let Some(name) = weak_lang_items::link_name(&attrs) {
2458 codegen_fn_attrs.export_name = Some(name);
2459 codegen_fn_attrs.link_name = Some(name);
2462 // Internal symbols to the standard library all have no_mangle semantics in
2463 // that they have defined symbol names present in the function name. This
2464 // also applies to weak symbols where they all have known symbol names.
2465 if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL) {
2466 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_MANGLE;