1 // Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! "Collection" is the process of determining the type and other external
12 //! details of each item in Rust. Collection is specifically concerned
13 //! with *interprocedural* things -- for example, for a function
14 //! definition, collection will figure out the type and signature of the
15 //! function, but it will not visit the *body* of the function in any way,
16 //! nor examine type annotations on local variables (that's the job of
19 //! Collecting is ultimately defined by a bundle of queries that
20 //! inquire after various facts about the items in the crate (e.g.,
21 //! `type_of`, `generics_of`, `predicates_of`, etc). See the `provide` function
24 //! At present, however, we do run collection across all items in the
25 //! crate as a kind of pass. This should eventually be factored away.
27 use astconv::{AstConv, Bounds};
29 use constrained_type_params as ctp;
30 use middle::lang_items::SizedTraitLangItem;
31 use middle::resolve_lifetime as rl;
32 use rustc::mir::mono::Linkage;
33 use rustc::ty::subst::Substs;
34 use rustc::ty::{ToPredicate, ReprOptions};
35 use rustc::ty::{self, AdtKind, ToPolyTraitRef, Ty, TyCtxt};
36 use rustc::ty::query::Providers;
37 use rustc::ty::util::IntTypeExt;
38 use rustc::ty::util::Discr;
39 use rustc::util::captures::Captures;
40 use rustc::util::nodemap::FxHashMap;
41 use rustc_target::spec::abi;
44 use syntax::ast::MetaItemKind;
45 use syntax::attr::{InlineAttr, list_contains_name, mark_used};
46 use syntax::codemap::Spanned;
47 use syntax::symbol::{Symbol, keywords};
48 use syntax::feature_gate;
49 use syntax_pos::{Span, DUMMY_SP};
51 use rustc::hir::{self, map as hir_map, CodegenFnAttrs, CodegenFnAttrFlags, Unsafety};
52 use rustc::hir::intravisit::{self, Visitor, NestedVisitorMap};
53 use rustc::hir::def::{Def, CtorKind};
54 use rustc::hir::def_id::{DefId, LOCAL_CRATE};
56 ///////////////////////////////////////////////////////////////////////////
59 pub fn collect_item_types<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
60 let mut visitor = CollectItemTypesVisitor { tcx: tcx };
61 tcx.hir.krate().visit_all_item_likes(&mut visitor.as_deep_visitor());
64 pub fn provide(providers: &mut Providers) {
65 *providers = Providers {
69 explicit_predicates_of,
71 type_param_predicates,
83 ///////////////////////////////////////////////////////////////////////////
85 /// Context specific to some particular item. This is what implements
86 /// AstConv. It has information about the predicates that are defined
87 /// on the trait. Unfortunately, this predicate information is
88 /// available in various different forms at various points in the
89 /// process. So we can't just store a pointer to e.g. the AST or the
90 /// parsed ty form, we have to be more flexible. To this end, the
91 /// `ItemCtxt` is parameterized by a `DefId` that it uses to satisfy
92 /// `get_type_parameter_bounds` requests, drawing the information from
93 /// the AST (`hir::Generics`), recursively.
94 pub struct ItemCtxt<'a,'tcx:'a> {
95 tcx: TyCtxt<'a, 'tcx, 'tcx>,
99 ///////////////////////////////////////////////////////////////////////////
101 struct CollectItemTypesVisitor<'a, 'tcx: 'a> {
102 tcx: TyCtxt<'a, 'tcx, 'tcx>
105 impl<'a, 'tcx> Visitor<'tcx> for CollectItemTypesVisitor<'a, 'tcx> {
106 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
107 NestedVisitorMap::OnlyBodies(&self.tcx.hir)
110 fn visit_item(&mut self, item: &'tcx hir::Item) {
111 convert_item(self.tcx, item.id);
112 intravisit::walk_item(self, item);
115 fn visit_generics(&mut self, generics: &'tcx hir::Generics) {
116 for param in generics.ty_params() {
117 if param.default.is_some() {
118 let def_id = self.tcx.hir.local_def_id(param.id);
119 self.tcx.type_of(def_id);
122 intravisit::walk_generics(self, generics);
125 fn visit_expr(&mut self, expr: &'tcx hir::Expr) {
126 if let hir::ExprClosure(..) = expr.node {
127 let def_id = self.tcx.hir.local_def_id(expr.id);
128 self.tcx.generics_of(def_id);
129 self.tcx.type_of(def_id);
131 intravisit::walk_expr(self, expr);
134 fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem) {
135 convert_trait_item(self.tcx, trait_item.id);
136 intravisit::walk_trait_item(self, trait_item);
139 fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem) {
140 convert_impl_item(self.tcx, impl_item.id);
141 intravisit::walk_impl_item(self, impl_item);
145 ///////////////////////////////////////////////////////////////////////////
146 // Utility types and common code for the above passes.
148 impl<'a, 'tcx> ItemCtxt<'a, 'tcx> {
149 pub fn new(tcx: TyCtxt<'a, 'tcx, 'tcx>, item_def_id: DefId)
150 -> ItemCtxt<'a,'tcx> {
158 impl<'a,'tcx> ItemCtxt<'a,'tcx> {
159 pub fn to_ty(&self, ast_ty: &hir::Ty) -> Ty<'tcx> {
160 AstConv::ast_ty_to_ty(self, ast_ty)
164 impl<'a, 'tcx> AstConv<'tcx, 'tcx> for ItemCtxt<'a, 'tcx> {
165 fn tcx<'b>(&'b self) -> TyCtxt<'b, 'tcx, 'tcx> { self.tcx }
167 fn get_type_parameter_bounds(&self,
170 -> ty::GenericPredicates<'tcx>
172 self.tcx.at(span).type_param_predicates((self.item_def_id, def_id))
175 fn re_infer(&self, _span: Span, _def: Option<&ty::GenericParamDef>)
176 -> Option<ty::Region<'tcx>> {
180 fn ty_infer(&self, span: Span) -> Ty<'tcx> {
185 "the type placeholder `_` is not allowed within types on item signatures"
186 ).span_label(span, "not allowed in type signatures")
191 fn projected_ty_from_poly_trait_ref(&self,
194 poly_trait_ref: ty::PolyTraitRef<'tcx>)
197 if let Some(trait_ref) = poly_trait_ref.no_late_bound_regions() {
198 self.tcx().mk_projection(item_def_id, trait_ref.substs)
200 // no late-bound regions, we can just ignore the binder
201 span_err!(self.tcx().sess, span, E0212,
202 "cannot extract an associated type from a higher-ranked trait bound \
208 fn normalize_ty(&self, _span: Span, ty: Ty<'tcx>) -> Ty<'tcx> {
209 // types in item signatures are not normalized, to avoid undue
214 fn set_tainted_by_errors(&self) {
215 // no obvious place to track this, just let it go
218 fn record_ty(&self, _hir_id: hir::HirId, _ty: Ty<'tcx>, _span: Span) {
219 // no place to record types from signatures?
223 fn type_param_predicates<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
224 (item_def_id, def_id): (DefId, DefId))
225 -> ty::GenericPredicates<'tcx> {
226 use rustc::hir::map::*;
229 // In the AST, bounds can derive from two places. Either
230 // written inline like `<T:Foo>` or in a where clause like
233 let param_id = tcx.hir.as_local_node_id(def_id).unwrap();
234 let param_owner = tcx.hir.ty_param_owner(param_id);
235 let param_owner_def_id = tcx.hir.local_def_id(param_owner);
236 let generics = tcx.generics_of(param_owner_def_id);
237 let index = generics.param_def_id_to_index[&def_id];
238 let ty = tcx.mk_ty_param(index, tcx.hir.ty_param_name(param_id).as_interned_str());
240 // Don't look for bounds where the type parameter isn't in scope.
241 let parent = if item_def_id == param_owner_def_id {
244 tcx.generics_of(item_def_id).parent
247 let mut result = parent.map_or(ty::GenericPredicates {
251 let icx = ItemCtxt::new(tcx, parent);
252 icx.get_type_parameter_bounds(DUMMY_SP, def_id)
255 let item_node_id = tcx.hir.as_local_node_id(item_def_id).unwrap();
256 let ast_generics = match tcx.hir.get(item_node_id) {
257 NodeTraitItem(item) => &item.generics,
259 NodeImplItem(item) => &item.generics,
263 ItemFn(.., ref generics, _) |
264 ItemImpl(_, _, _, ref generics, ..) |
265 ItemTy(_, ref generics) |
266 ItemEnum(_, ref generics) |
267 ItemStruct(_, ref generics) |
268 ItemUnion(_, ref generics) => generics,
269 ItemTrait(_, _, ref generics, ..) => {
270 // Implied `Self: Trait` and supertrait bounds.
271 if param_id == item_node_id {
272 result.predicates.push(ty::TraitRef {
274 substs: Substs::identity_for_item(tcx, item_def_id)
283 NodeForeignItem(item) => {
285 ForeignItemFn(_, _, ref generics) => generics,
293 let icx = ItemCtxt::new(tcx, item_def_id);
294 result.predicates.extend(
295 icx.type_parameter_bounds_in_generics(ast_generics, param_id, ty));
299 impl<'a, 'tcx> ItemCtxt<'a, 'tcx> {
300 /// Find bounds from hir::Generics. This requires scanning through the
301 /// AST. We do this to avoid having to convert *all* the bounds, which
302 /// would create artificial cycles. Instead we can only convert the
303 /// bounds for a type parameter `X` if `X::Foo` is used.
304 fn type_parameter_bounds_in_generics(&self,
305 ast_generics: &hir::Generics,
306 param_id: ast::NodeId,
308 -> Vec<ty::Predicate<'tcx>>
311 ast_generics.ty_params()
312 .filter(|p| p.id == param_id)
313 .flat_map(|p| p.bounds.iter())
314 .flat_map(|b| predicates_from_bound(self, ty, b));
316 let from_where_clauses =
317 ast_generics.where_clause
320 .filter_map(|wp| match *wp {
321 hir::WherePredicate::BoundPredicate(ref bp) => Some(bp),
324 .filter(|bp| is_param(self.tcx, &bp.bounded_ty, param_id))
325 .flat_map(|bp| bp.bounds.iter())
326 .flat_map(|b| predicates_from_bound(self, ty, b));
328 from_ty_params.chain(from_where_clauses).collect()
332 /// Tests whether this is the AST for a reference to the type
333 /// parameter with id `param_id`. We use this so as to avoid running
334 /// `ast_ty_to_ty`, because we want to avoid triggering an all-out
335 /// conversion of the type to avoid inducing unnecessary cycles.
336 fn is_param<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
338 param_id: ast::NodeId)
341 if let hir::TyPath(hir::QPath::Resolved(None, ref path)) = ast_ty.node {
343 Def::SelfTy(Some(def_id), None) |
344 Def::TyParam(def_id) => {
345 def_id == tcx.hir.local_def_id(param_id)
354 fn convert_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, item_id: ast::NodeId) {
355 let it = tcx.hir.expect_item(item_id);
356 debug!("convert: item {} with id {}", it.name, it.id);
357 let def_id = tcx.hir.local_def_id(item_id);
359 // These don't define types.
360 hir::ItemExternCrate(_) |
363 hir::ItemGlobalAsm(_) => {}
364 hir::ItemForeignMod(ref foreign_mod) => {
365 for item in &foreign_mod.items {
366 let def_id = tcx.hir.local_def_id(item.id);
367 tcx.generics_of(def_id);
369 tcx.predicates_of(def_id);
370 if let hir::ForeignItemFn(..) = item.node {
375 hir::ItemEnum(ref enum_definition, _) => {
376 tcx.generics_of(def_id);
378 tcx.predicates_of(def_id);
379 convert_enum_variant_types(tcx, def_id, &enum_definition.variants);
381 hir::ItemImpl(..) => {
382 tcx.generics_of(def_id);
384 tcx.impl_trait_ref(def_id);
385 tcx.predicates_of(def_id);
387 hir::ItemTrait(..) => {
388 tcx.generics_of(def_id);
389 tcx.trait_def(def_id);
390 tcx.at(it.span).super_predicates_of(def_id);
391 tcx.predicates_of(def_id);
393 hir::ItemTraitAlias(..) => {
394 span_err!(tcx.sess, it.span, E0645,
395 "trait aliases are not yet implemented (see issue #41517)");
397 hir::ItemStruct(ref struct_def, _) |
398 hir::ItemUnion(ref struct_def, _) => {
399 tcx.generics_of(def_id);
401 tcx.predicates_of(def_id);
403 for f in struct_def.fields() {
404 let def_id = tcx.hir.local_def_id(f.id);
405 tcx.generics_of(def_id);
407 tcx.predicates_of(def_id);
410 if !struct_def.is_struct() {
411 convert_variant_ctor(tcx, struct_def.id());
414 hir::ItemExistential(..) |
415 hir::ItemTy(..) | hir::ItemStatic(..) | hir::ItemConst(..) | hir::ItemFn(..) => {
416 tcx.generics_of(def_id);
418 tcx.predicates_of(def_id);
419 if let hir::ItemFn(..) = it.node {
426 fn convert_trait_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, trait_item_id: ast::NodeId) {
427 let trait_item = tcx.hir.expect_trait_item(trait_item_id);
428 let def_id = tcx.hir.local_def_id(trait_item.id);
429 tcx.generics_of(def_id);
431 match trait_item.node {
432 hir::TraitItemKind::Const(..) |
433 hir::TraitItemKind::Type(_, Some(_)) |
434 hir::TraitItemKind::Method(..) => {
436 if let hir::TraitItemKind::Method(..) = trait_item.node {
441 hir::TraitItemKind::Type(_, None) => {}
444 tcx.predicates_of(def_id);
447 fn convert_impl_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, impl_item_id: ast::NodeId) {
448 let def_id = tcx.hir.local_def_id(impl_item_id);
449 tcx.generics_of(def_id);
451 tcx.predicates_of(def_id);
452 if let hir::ImplItemKind::Method(..) = tcx.hir.expect_impl_item(impl_item_id).node {
457 fn convert_variant_ctor<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
458 ctor_id: ast::NodeId) {
459 let def_id = tcx.hir.local_def_id(ctor_id);
460 tcx.generics_of(def_id);
462 tcx.predicates_of(def_id);
465 fn convert_enum_variant_types<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
467 variants: &[hir::Variant]) {
468 let def = tcx.adt_def(def_id);
469 let repr_type = def.repr.discr_type();
470 let initial = repr_type.initial_discriminant(tcx);
471 let mut prev_discr = None::<Discr<'tcx>>;
473 // fill the discriminant values and field types
474 for variant in variants {
475 let wrapped_discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
476 prev_discr = Some(if let Some(ref e) = variant.node.disr_expr {
477 let expr_did = tcx.hir.local_def_id(e.id);
478 def.eval_explicit_discr(tcx, expr_did)
479 } else if let Some(discr) = repr_type.disr_incr(tcx, prev_discr) {
482 struct_span_err!(tcx.sess, variant.span, E0370,
483 "enum discriminant overflowed")
484 .span_label(variant.span, format!("overflowed on value after {}",
485 prev_discr.unwrap()))
486 .note(&format!("explicitly set `{} = {}` if that is desired outcome",
487 variant.node.name, wrapped_discr))
490 }.unwrap_or(wrapped_discr));
492 for f in variant.node.data.fields() {
493 let def_id = tcx.hir.local_def_id(f.id);
494 tcx.generics_of(def_id);
496 tcx.predicates_of(def_id);
499 // Convert the ctor, if any. This also registers the variant as
501 convert_variant_ctor(tcx, variant.node.data.id());
505 fn convert_struct_variant<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
508 discr: ty::VariantDiscr,
509 def: &hir::VariantData)
511 let mut seen_fields: FxHashMap<ast::Ident, Span> = FxHashMap();
512 let node_id = tcx.hir.as_local_node_id(did).unwrap();
513 let fields = def.fields().iter().map(|f| {
514 let fid = tcx.hir.local_def_id(f.id);
515 let dup_span = seen_fields.get(&f.ident.modern()).cloned();
516 if let Some(prev_span) = dup_span {
517 struct_span_err!(tcx.sess, f.span, E0124,
518 "field `{}` is already declared",
520 .span_label(f.span, "field already declared")
521 .span_label(prev_span, format!("`{}` first declared here", f.ident))
524 seen_fields.insert(f.ident.modern(), f.span);
530 vis: ty::Visibility::from_hir(&f.vis, node_id, tcx)
538 ctor_kind: CtorKind::from_hir(def),
542 fn adt_def<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
544 -> &'tcx ty::AdtDef {
545 use rustc::hir::map::*;
548 let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
549 let item = match tcx.hir.get(node_id) {
550 NodeItem(item) => item,
554 let repr = ReprOptions::new(tcx, def_id);
555 let (kind, variants) = match item.node {
556 ItemEnum(ref def, _) => {
557 let mut distance_from_explicit = 0;
558 (AdtKind::Enum, def.variants.iter().map(|v| {
559 let did = tcx.hir.local_def_id(v.node.data.id());
560 let discr = if let Some(ref e) = v.node.disr_expr {
561 distance_from_explicit = 0;
562 ty::VariantDiscr::Explicit(tcx.hir.local_def_id(e.id))
564 ty::VariantDiscr::Relative(distance_from_explicit)
566 distance_from_explicit += 1;
568 convert_struct_variant(tcx, did, v.node.name, discr, &v.node.data)
571 ItemStruct(ref def, _) => {
572 // Use separate constructor id for unit/tuple structs and reuse did for braced structs.
573 let ctor_id = if !def.is_struct() {
574 Some(tcx.hir.local_def_id(def.id()))
578 (AdtKind::Struct, vec![
579 convert_struct_variant(tcx, ctor_id.unwrap_or(def_id), item.name,
580 ty::VariantDiscr::Relative(0), def)
583 ItemUnion(ref def, _) => {
584 (AdtKind::Union, vec![
585 convert_struct_variant(tcx, def_id, item.name,
586 ty::VariantDiscr::Relative(0), def)
591 tcx.alloc_adt_def(def_id, kind, variants, repr)
594 /// Ensures that the super-predicates of the trait with def-id
595 /// trait_def_id are converted and stored. This also ensures that
596 /// the transitive super-predicates are converted;
597 fn super_predicates_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
599 -> ty::GenericPredicates<'tcx> {
600 debug!("super_predicates(trait_def_id={:?})", trait_def_id);
601 let trait_node_id = tcx.hir.as_local_node_id(trait_def_id).unwrap();
603 let item = match tcx.hir.get(trait_node_id) {
604 hir_map::NodeItem(item) => item,
605 _ => bug!("trait_node_id {} is not an item", trait_node_id)
608 let (generics, bounds) = match item.node {
609 hir::ItemTrait(.., ref generics, ref supertraits, _) => (generics, supertraits),
610 hir::ItemTraitAlias(ref generics, ref supertraits) => (generics, supertraits),
611 _ => span_bug!(item.span,
612 "super_predicates invoked on non-trait"),
615 let icx = ItemCtxt::new(tcx, trait_def_id);
617 // Convert the bounds that follow the colon, e.g. `Bar+Zed` in `trait Foo : Bar+Zed`.
618 let self_param_ty = tcx.mk_self_type();
619 let superbounds1 = compute_bounds(&icx,
625 let superbounds1 = superbounds1.predicates(tcx, self_param_ty);
627 // Convert any explicit superbounds in the where clause,
628 // e.g. `trait Foo where Self : Bar`:
629 let superbounds2 = icx.type_parameter_bounds_in_generics(generics, item.id, self_param_ty);
631 // Combine the two lists to form the complete set of superbounds:
632 let superbounds: Vec<_> = superbounds1.into_iter().chain(superbounds2).collect();
634 // Now require that immediate supertraits are converted,
635 // which will, in turn, reach indirect supertraits.
636 for bound in superbounds.iter().filter_map(|p| p.to_opt_poly_trait_ref()) {
637 tcx.at(item.span).super_predicates_of(bound.def_id());
640 ty::GenericPredicates {
642 predicates: superbounds
646 fn trait_def<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
648 -> &'tcx ty::TraitDef {
649 let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
650 let item = tcx.hir.expect_item(node_id);
652 let (is_auto, unsafety) = match item.node {
653 hir::ItemTrait(is_auto, unsafety, ..) => (is_auto == hir::IsAuto::Yes, unsafety),
654 hir::ItemTraitAlias(..) => (false, hir::Unsafety::Normal),
655 _ => span_bug!(item.span, "trait_def_of_item invoked on non-trait"),
658 let paren_sugar = tcx.has_attr(def_id, "rustc_paren_sugar");
659 if paren_sugar && !tcx.features().unboxed_closures {
660 let mut err = tcx.sess.struct_span_err(
662 "the `#[rustc_paren_sugar]` attribute is a temporary means of controlling \
663 which traits can use parenthetical notation");
665 "add `#![feature(unboxed_closures)]` to \
666 the crate attributes to use it");
670 let def_path_hash = tcx.def_path_hash(def_id);
671 let def = ty::TraitDef::new(def_id,
676 tcx.alloc_trait_def(def)
679 fn has_late_bound_regions<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
680 node: hir_map::Node<'tcx>)
682 struct LateBoundRegionsDetector<'a, 'tcx: 'a> {
683 tcx: TyCtxt<'a, 'tcx, 'tcx>,
684 outer_index: ty::DebruijnIndex,
685 has_late_bound_regions: Option<Span>,
688 impl<'a, 'tcx> Visitor<'tcx> for LateBoundRegionsDetector<'a, 'tcx> {
689 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
690 NestedVisitorMap::None
693 fn visit_ty(&mut self, ty: &'tcx hir::Ty) {
694 if self.has_late_bound_regions.is_some() { return }
696 hir::TyBareFn(..) => {
697 self.outer_index.shift_in(1);
698 intravisit::walk_ty(self, ty);
699 self.outer_index.shift_out(1);
701 _ => intravisit::walk_ty(self, ty)
705 fn visit_poly_trait_ref(&mut self,
706 tr: &'tcx hir::PolyTraitRef,
707 m: hir::TraitBoundModifier) {
708 if self.has_late_bound_regions.is_some() { return }
709 self.outer_index.shift_in(1);
710 intravisit::walk_poly_trait_ref(self, tr, m);
711 self.outer_index.shift_out(1);
714 fn visit_lifetime(&mut self, lt: &'tcx hir::Lifetime) {
715 if self.has_late_bound_regions.is_some() { return }
717 let hir_id = self.tcx.hir.node_to_hir_id(lt.id);
718 match self.tcx.named_region(hir_id) {
719 Some(rl::Region::Static) | Some(rl::Region::EarlyBound(..)) => {}
720 Some(rl::Region::LateBound(debruijn, _, _)) |
721 Some(rl::Region::LateBoundAnon(debruijn, _))
722 if debruijn < self.outer_index => {}
723 Some(rl::Region::LateBound(..)) |
724 Some(rl::Region::LateBoundAnon(..)) |
725 Some(rl::Region::Free(..)) |
727 self.has_late_bound_regions = Some(lt.span);
733 fn has_late_bound_regions<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
734 generics: &'tcx hir::Generics,
735 decl: &'tcx hir::FnDecl)
737 let mut visitor = LateBoundRegionsDetector {
739 outer_index: ty::INNERMOST,
740 has_late_bound_regions: None,
742 for lifetime in generics.lifetimes() {
743 let hir_id = tcx.hir.node_to_hir_id(lifetime.lifetime.id);
744 if tcx.is_late_bound(hir_id) {
745 return Some(lifetime.lifetime.span);
748 visitor.visit_fn_decl(decl);
749 visitor.has_late_bound_regions
753 hir_map::NodeTraitItem(item) => match item.node {
754 hir::TraitItemKind::Method(ref sig, _) =>
755 has_late_bound_regions(tcx, &item.generics, &sig.decl),
758 hir_map::NodeImplItem(item) => match item.node {
759 hir::ImplItemKind::Method(ref sig, _) =>
760 has_late_bound_regions(tcx, &item.generics, &sig.decl),
763 hir_map::NodeForeignItem(item) => match item.node {
764 hir::ForeignItemFn(ref fn_decl, _, ref generics) =>
765 has_late_bound_regions(tcx, generics, fn_decl),
768 hir_map::NodeItem(item) => match item.node {
769 hir::ItemFn(ref fn_decl, .., ref generics, _) =>
770 has_late_bound_regions(tcx, generics, fn_decl),
777 fn generics_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
779 -> &'tcx ty::Generics {
780 use rustc::hir::map::*;
783 let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
785 let node = tcx.hir.get(node_id);
786 let parent_def_id = match node {
792 let parent_id = tcx.hir.get_parent(node_id);
793 Some(tcx.hir.local_def_id(parent_id))
795 NodeExpr(&hir::Expr { node: hir::ExprClosure(..), .. }) => {
796 Some(tcx.closure_base_def_id(def_id))
800 ItemExistential(hir::ExistTy { impl_trait_fn, .. }) => impl_trait_fn,
807 let mut opt_self = None;
808 let mut allow_defaults = false;
810 let no_generics = hir::Generics::empty();
811 let ast_generics = match node {
812 NodeTraitItem(item) => &item.generics,
814 NodeImplItem(item) => &item.generics,
818 ItemFn(.., ref generics, _) |
819 ItemImpl(_, _, _, ref generics, ..) => generics,
821 ItemTy(_, ref generics) |
822 ItemEnum(_, ref generics) |
823 ItemStruct(_, ref generics) |
824 ItemExistential(hir::ExistTy { ref generics, .. }) |
825 ItemUnion(_, ref generics) => {
826 allow_defaults = true;
830 ItemTrait(_, _, ref generics, ..) | ItemTraitAlias(ref generics, ..) => {
831 // Add in the self type parameter.
833 // Something of a hack: use the node id for the trait, also as
834 // the node id for the Self type parameter.
835 let param_id = item.id;
837 opt_self = Some(ty::GenericParamDef {
839 name: keywords::SelfType.name().as_interned_str(),
840 def_id: tcx.hir.local_def_id(param_id),
841 pure_wrt_drop: false,
842 kind: ty::GenericParamDefKind::Type {
844 object_lifetime_default: rl::Set1::Empty,
849 allow_defaults = true;
857 NodeForeignItem(item) => {
859 ForeignItemStatic(..) => &no_generics,
860 ForeignItemFn(_, _, ref generics) => generics,
861 ForeignItemType => &no_generics,
865 NodeTy(&hir::Ty { node: hir::TyImplTraitExistential(..), .. }) => {
866 bug!("impl Trait is desugared to existential type items");
872 let has_self = opt_self.is_some();
873 let mut parent_has_self = false;
874 let mut own_start = has_self as u32;
875 let parent_count = parent_def_id.map_or(0, |def_id| {
876 let generics = tcx.generics_of(def_id);
877 assert_eq!(has_self, false);
878 parent_has_self = generics.has_self;
879 own_start = generics.count() as u32;
880 generics.parent_count + generics.params.len()
883 let mut params: Vec<_> = opt_self.into_iter().collect();
885 let early_lifetimes = early_bound_lifetimes_from_generics(tcx, ast_generics);
886 params.extend(early_lifetimes.enumerate().map(|(i, l)| {
887 ty::GenericParamDef {
888 name: l.lifetime.name.name().as_interned_str(),
889 index: own_start + i as u32,
890 def_id: tcx.hir.local_def_id(l.lifetime.id),
891 pure_wrt_drop: l.pure_wrt_drop,
892 kind: ty::GenericParamDefKind::Lifetime,
896 let hir_id = tcx.hir.node_to_hir_id(node_id);
897 let object_lifetime_defaults = tcx.object_lifetime_defaults(hir_id);
899 // Now create the real type parameters.
900 let type_start = own_start - has_self as u32 + params.len() as u32;
901 params.extend(ast_generics.ty_params().enumerate().map(|(i, p)| {
902 if p.name == keywords::SelfType.name() {
903 span_bug!(p.span, "`Self` should not be the name of a regular parameter");
906 if !allow_defaults && p.default.is_some() {
907 if !tcx.features().default_type_parameter_fallback {
909 lint::builtin::INVALID_TYPE_PARAM_DEFAULT,
912 &format!("defaults for type parameters are only allowed in `struct`, \
913 `enum`, `type`, or `trait` definitions."));
917 ty::GenericParamDef {
918 index: type_start + i as u32,
919 name: p.name.as_interned_str(),
920 def_id: tcx.hir.local_def_id(p.id),
921 pure_wrt_drop: p.pure_wrt_drop,
922 kind: ty::GenericParamDefKind::Type {
923 has_default: p.default.is_some(),
924 object_lifetime_default:
925 object_lifetime_defaults.as_ref().map_or(rl::Set1::Empty, |o| o[i]),
926 synthetic: p.synthetic,
931 // provide junk type parameter defs - the only place that
932 // cares about anything but the length is instantiation,
933 // and we don't do that for closures.
934 if let NodeExpr(&hir::Expr { node: hir::ExprClosure(.., gen), .. }) = node {
935 let dummy_args = if gen.is_some() {
936 &["<yield_ty>", "<return_ty>", "<witness>"][..]
938 &["<closure_kind>", "<closure_signature>"][..]
941 for (i, &arg) in dummy_args.iter().enumerate() {
942 params.push(ty::GenericParamDef {
943 index: type_start + i as u32,
944 name: Symbol::intern(arg).as_interned_str(),
946 pure_wrt_drop: false,
947 kind: ty::GenericParamDefKind::Type {
949 object_lifetime_default: rl::Set1::Empty,
955 tcx.with_freevars(node_id, |fv| {
956 params.extend(fv.iter().zip((dummy_args.len() as u32)..).map(|(_, i)| {
957 ty::GenericParamDef {
958 index: type_start + i,
959 name: Symbol::intern("<upvar>").as_interned_str(),
961 pure_wrt_drop: false,
962 kind: ty::GenericParamDefKind::Type {
964 object_lifetime_default: rl::Set1::Empty,
972 let param_def_id_to_index = params.iter()
973 .map(|param| (param.def_id, param.index))
976 tcx.alloc_generics(ty::Generics {
977 parent: parent_def_id,
980 param_def_id_to_index,
981 has_self: has_self || parent_has_self,
982 has_late_bound_regions: has_late_bound_regions(tcx, node),
986 fn type_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
989 use rustc::hir::map::*;
992 let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
994 let icx = ItemCtxt::new(tcx, def_id);
996 match tcx.hir.get(node_id) {
997 NodeTraitItem(item) => {
999 TraitItemKind::Method(..) => {
1000 let substs = Substs::identity_for_item(tcx, def_id);
1001 tcx.mk_fn_def(def_id, substs)
1003 TraitItemKind::Const(ref ty, _) |
1004 TraitItemKind::Type(_, Some(ref ty)) => icx.to_ty(ty),
1005 TraitItemKind::Type(_, None) => {
1006 span_bug!(item.span, "associated type missing default");
1011 NodeImplItem(item) => {
1013 ImplItemKind::Method(..) => {
1014 let substs = Substs::identity_for_item(tcx, def_id);
1015 tcx.mk_fn_def(def_id, substs)
1017 ImplItemKind::Const(ref ty, _) => icx.to_ty(ty),
1018 ImplItemKind::Type(ref ty) => {
1019 if tcx.impl_trait_ref(tcx.hir.get_parent_did(node_id)).is_none() {
1020 span_err!(tcx.sess, item.span, E0202,
1021 "associated types are not allowed in inherent impls");
1031 ItemStatic(ref t, ..) | ItemConst(ref t, _) |
1032 ItemTy(ref t, _) | ItemImpl(.., ref t, _) => {
1036 let substs = Substs::identity_for_item(tcx, def_id);
1037 tcx.mk_fn_def(def_id, substs)
1042 let def = tcx.adt_def(def_id);
1043 let substs = Substs::identity_for_item(tcx, def_id);
1044 tcx.mk_adt(def, substs)
1046 // this is only reachable once we have named existential types
1047 ItemExistential(hir::ExistTy { impl_trait_fn: None, .. }) => unimplemented!(),
1048 // existential types desugared from impl Trait
1049 ItemExistential(hir::ExistTy { impl_trait_fn: Some(owner), .. }) => {
1050 tcx.typeck_tables_of(owner).concrete_existential_types[&def_id]
1052 ItemTrait(..) | ItemTraitAlias(..) |
1054 ItemForeignMod(..) |
1056 ItemExternCrate(..) |
1060 "compute_type_of_item: unexpected item type: {:?}",
1066 NodeForeignItem(foreign_item) => {
1067 match foreign_item.node {
1068 ForeignItemFn(..) => {
1069 let substs = Substs::identity_for_item(tcx, def_id);
1070 tcx.mk_fn_def(def_id, substs)
1072 ForeignItemStatic(ref t, _) => icx.to_ty(t),
1073 ForeignItemType => tcx.mk_foreign(def_id),
1077 NodeStructCtor(&ref def) |
1078 NodeVariant(&Spanned { node: hir::Variant_ { data: ref def, .. }, .. }) => {
1080 VariantData::Unit(..) | VariantData::Struct(..) => {
1081 tcx.type_of(tcx.hir.get_parent_did(node_id))
1083 VariantData::Tuple(..) => {
1084 let substs = Substs::identity_for_item(tcx, def_id);
1085 tcx.mk_fn_def(def_id, substs)
1090 NodeField(field) => icx.to_ty(&field.ty),
1092 NodeExpr(&hir::Expr { node: hir::ExprClosure(.., gen), .. }) => {
1094 let hir_id = tcx.hir.node_to_hir_id(node_id);
1095 return tcx.typeck_tables_of(def_id).node_id_to_type(hir_id);
1098 let substs = ty::ClosureSubsts {
1099 substs: Substs::identity_for_item(tcx, def_id),
1102 tcx.mk_closure(def_id, substs)
1105 NodeAnonConst(_) => match tcx.hir.get(tcx.hir.get_parent_node(node_id)) {
1106 NodeTy(&hir::Ty { node: TyArray(_, ref constant), .. }) |
1107 NodeTy(&hir::Ty { node: TyTypeof(ref constant), .. }) |
1108 NodeExpr(&hir::Expr { node: ExprRepeat(_, ref constant), .. })
1109 if constant.id == node_id => tcx.types.usize,
1111 NodeVariant(&Spanned { node: Variant_ { disr_expr: Some(ref e), .. }, .. })
1112 if e.id == node_id => {
1113 tcx.adt_def(tcx.hir.get_parent_did(node_id))
1114 .repr.discr_type().to_ty(tcx)
1118 bug!("unexpected const parent in type_of_def_id(): {:?}", x);
1122 NodeTyParam(&hir::TyParam { default: Some(ref ty), .. }) => {
1127 bug!("unexpected sort of node in type_of_def_id(): {:?}", x);
1132 fn fn_sig<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1134 -> ty::PolyFnSig<'tcx> {
1135 use rustc::hir::map::*;
1138 let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
1140 let icx = ItemCtxt::new(tcx, def_id);
1142 match tcx.hir.get(node_id) {
1143 NodeTraitItem(&hir::TraitItem { node: TraitItemKind::Method(ref sig, _), .. }) |
1144 NodeImplItem(&hir::ImplItem { node: ImplItemKind::Method(ref sig, _), .. }) => {
1145 AstConv::ty_of_fn(&icx, sig.unsafety, sig.abi, &sig.decl)
1148 NodeItem(&hir::Item { node: ItemFn(ref decl, unsafety, _, abi, _, _), .. }) => {
1149 AstConv::ty_of_fn(&icx, unsafety, abi, decl)
1152 NodeForeignItem(&hir::ForeignItem { node: ForeignItemFn(ref fn_decl, _, _), .. }) => {
1153 let abi = tcx.hir.get_foreign_abi(node_id);
1154 compute_sig_of_foreign_fn_decl(tcx, def_id, fn_decl, abi)
1157 NodeStructCtor(&VariantData::Tuple(ref fields, _)) |
1158 NodeVariant(&Spanned { node: hir::Variant_ {
1159 data: VariantData::Tuple(ref fields, _), ..
1161 let ty = tcx.type_of(tcx.hir.get_parent_did(node_id));
1162 let inputs = fields.iter().map(|f| {
1163 tcx.type_of(tcx.hir.local_def_id(f.id))
1165 ty::Binder::bind(tcx.mk_fn_sig(
1169 hir::Unsafety::Normal,
1174 NodeExpr(&hir::Expr { node: hir::ExprClosure(..), .. }) => {
1175 // Closure signatures are not like other function
1176 // signatures and cannot be accessed through `fn_sig`. For
1177 // example, a closure signature excludes the `self`
1178 // argument. In any case they are embedded within the
1179 // closure type as part of the `ClosureSubsts`.
1182 // the signature of a closure, you should use the
1183 // `closure_sig` method on the `ClosureSubsts`:
1185 // closure_substs.closure_sig(def_id, tcx)
1187 // or, inside of an inference context, you can use
1189 // infcx.closure_sig(def_id, closure_substs)
1190 bug!("to get the signature of a closure, use `closure_sig()` not `fn_sig()`");
1194 bug!("unexpected sort of node in fn_sig(): {:?}", x);
1199 fn impl_trait_ref<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1201 -> Option<ty::TraitRef<'tcx>> {
1202 let icx = ItemCtxt::new(tcx, def_id);
1204 let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
1205 match tcx.hir.expect_item(node_id).node {
1206 hir::ItemImpl(.., ref opt_trait_ref, _, _) => {
1207 opt_trait_ref.as_ref().map(|ast_trait_ref| {
1208 let selfty = tcx.type_of(def_id);
1209 AstConv::instantiate_mono_trait_ref(&icx, ast_trait_ref, selfty)
1216 fn impl_polarity<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1218 -> hir::ImplPolarity {
1219 let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
1220 match tcx.hir.expect_item(node_id).node {
1221 hir::ItemImpl(_, polarity, ..) => polarity,
1222 ref item => bug!("impl_polarity: {:?} not an impl", item)
1226 // Is it marked with ?Sized
1227 fn is_unsized<'gcx: 'tcx, 'tcx>(astconv: &AstConv<'gcx, 'tcx>,
1228 ast_bounds: &[hir::TyParamBound],
1231 let tcx = astconv.tcx();
1233 // Try to find an unbound in bounds.
1234 let mut unbound = None;
1235 for ab in ast_bounds {
1236 if let &hir::TraitTyParamBound(ref ptr, hir::TraitBoundModifier::Maybe) = ab {
1237 if unbound.is_none() {
1238 unbound = Some(ptr.trait_ref.clone());
1240 span_err!(tcx.sess, span, E0203,
1241 "type parameter has more than one relaxed default \
1242 bound, only one is supported");
1247 let kind_id = tcx.lang_items().require(SizedTraitLangItem);
1250 // FIXME(#8559) currently requires the unbound to be built-in.
1251 if let Ok(kind_id) = kind_id {
1252 if tpb.path.def != Def::Trait(kind_id) {
1253 tcx.sess.span_warn(span,
1254 "default bound relaxed for a type parameter, but \
1255 this does nothing because the given bound is not \
1256 a default. Only `?Sized` is supported");
1260 _ if kind_id.is_ok() => {
1263 // No lang item for Sized, so we can't add it as a bound.
1270 /// Returns the early-bound lifetimes declared in this generics
1271 /// listing. For anything other than fns/methods, this is just all
1272 /// the lifetimes that are declared. For fns or methods, we have to
1273 /// screen out those that do not appear in any where-clauses etc using
1274 /// `resolve_lifetime::early_bound_lifetimes`.
1275 fn early_bound_lifetimes_from_generics<'a, 'tcx>(
1276 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1277 ast_generics: &'a hir::Generics)
1278 -> impl Iterator<Item=&'a hir::LifetimeDef> + Captures<'tcx>
1283 let hir_id = tcx.hir.node_to_hir_id(l.lifetime.id);
1284 !tcx.is_late_bound(hir_id)
1288 fn predicates_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1290 -> ty::GenericPredicates<'tcx> {
1291 let explicit = explicit_predicates_of(tcx, def_id);
1292 let predicates = if tcx.sess.features_untracked().infer_outlives_requirements {
1293 [&explicit.predicates[..], &tcx.inferred_outlives_of(def_id)[..]].concat()
1294 } else { explicit.predicates };
1296 ty::GenericPredicates {
1297 parent: explicit.parent,
1298 predicates: predicates,
1302 pub fn explicit_predicates_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1304 -> ty::GenericPredicates<'tcx> {
1305 use rustc::hir::map::*;
1308 debug!("explicit_predicates_of(def_id={:?})", def_id);
1310 let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
1311 let node = tcx.hir.get(node_id);
1313 let mut is_trait = None;
1314 let mut is_default_impl_trait = None;
1316 let icx = ItemCtxt::new(tcx, def_id);
1317 let no_generics = hir::Generics::empty();
1318 let ast_generics = match node {
1319 NodeTraitItem(item) => &item.generics,
1320 NodeImplItem(item) => &item.generics,
1324 ItemImpl(_, _, defaultness, ref generics, ..) => {
1325 if defaultness.is_default() {
1326 is_default_impl_trait = tcx.impl_trait_ref(def_id);
1330 ItemFn(.., ref generics, _) |
1331 ItemTy(_, ref generics) |
1332 ItemEnum(_, ref generics) |
1333 ItemStruct(_, ref generics) |
1334 ItemUnion(_, ref generics) => generics,
1336 ItemTrait(_, _, ref generics, .., ref items) => {
1337 is_trait = Some((ty::TraitRef {
1339 substs: Substs::identity_for_item(tcx, def_id)
1343 ItemExistential(ref exist_ty) => {
1344 let substs = Substs::identity_for_item(tcx, def_id);
1345 let anon_ty = tcx.mk_anon(def_id, substs);
1347 // Collect the bounds, i.e. the `A+B+'c` in `impl A+B+'c`.
1348 let bounds = compute_bounds(&icx,
1351 SizedByDefault::Yes,
1352 tcx.def_span(def_id));
1354 let predicates = bounds.predicates(tcx, anon_ty);
1356 return ty::GenericPredicates {
1358 predicates: predicates
1366 NodeForeignItem(item) => {
1368 ForeignItemStatic(..) => &no_generics,
1369 ForeignItemFn(_, _, ref generics) => generics,
1370 ForeignItemType => &no_generics,
1377 let generics = tcx.generics_of(def_id);
1378 let parent_count = generics.parent_count as u32;
1379 let has_own_self = generics.has_self && parent_count == 0;
1381 let mut predicates = vec![];
1383 // Below we'll consider the bounds on the type parameters (including `Self`)
1384 // and the explicit where-clauses, but to get the full set of predicates
1385 // on a trait we need to add in the supertrait bounds and bounds found on
1386 // associated types.
1387 if let Some((trait_ref, _)) = is_trait {
1388 predicates = tcx.super_predicates_of(def_id).predicates;
1390 // Add in a predicate that `Self:Trait` (where `Trait` is the
1391 // current trait). This is needed for builtin bounds.
1392 predicates.push(trait_ref.to_poly_trait_ref().to_predicate());
1395 // In default impls, we can assume that the self type implements
1396 // the trait. So in:
1398 // default impl Foo for Bar { .. }
1400 // we add a default where clause `Foo: Bar`. We do a similar thing for traits
1401 // (see below). Recall that a default impl is not itself an impl, but rather a
1402 // set of defaults that can be incorporated into another impl.
1403 if let Some(trait_ref) = is_default_impl_trait {
1404 predicates.push(trait_ref.to_poly_trait_ref().to_predicate());
1407 // Collect the region predicates that were declared inline as
1408 // well. In the case of parameters declared on a fn or method, we
1409 // have to be careful to only iterate over early-bound regions.
1410 let mut index = parent_count + has_own_self as u32;
1411 for param in early_bound_lifetimes_from_generics(tcx, ast_generics) {
1412 let region = tcx.mk_region(ty::ReEarlyBound(ty::EarlyBoundRegion {
1413 def_id: tcx.hir.local_def_id(param.lifetime.id),
1415 name: param.lifetime.name.name().as_interned_str(),
1419 for bound in ¶m.bounds {
1420 let bound_region = AstConv::ast_region_to_region(&icx, bound, None);
1421 let outlives = ty::Binder::bind(ty::OutlivesPredicate(region, bound_region));
1422 predicates.push(outlives.to_predicate());
1426 // Collect the predicates that were written inline by the user on each
1427 // type parameter (e.g., `<T:Foo>`).
1428 for param in ast_generics.ty_params() {
1429 let param_ty = ty::ParamTy::new(index, param.name.as_interned_str()).to_ty(tcx);
1432 let bounds = compute_bounds(&icx,
1435 SizedByDefault::Yes,
1437 predicates.extend(bounds.predicates(tcx, param_ty));
1440 // Add in the bounds that appear in the where-clause
1441 let where_clause = &ast_generics.where_clause;
1442 for predicate in &where_clause.predicates {
1444 &hir::WherePredicate::BoundPredicate(ref bound_pred) => {
1445 let ty = icx.to_ty(&bound_pred.bounded_ty);
1447 for bound in bound_pred.bounds.iter() {
1449 &hir::TyParamBound::TraitTyParamBound(ref poly_trait_ref, _) => {
1450 let mut projections = Vec::new();
1453 AstConv::instantiate_poly_trait_ref(&icx,
1458 predicates.push(trait_ref.to_predicate());
1460 for projection in &projections {
1461 predicates.push(projection.to_predicate());
1465 &hir::TyParamBound::RegionTyParamBound(ref lifetime) => {
1466 let region = AstConv::ast_region_to_region(&icx,
1469 let pred = ty::Binder::bind(ty::OutlivesPredicate(ty, region));
1470 predicates.push(ty::Predicate::TypeOutlives(pred))
1476 &hir::WherePredicate::RegionPredicate(ref region_pred) => {
1477 let r1 = AstConv::ast_region_to_region(&icx, ®ion_pred.lifetime, None);
1478 for bound in ®ion_pred.bounds {
1479 let r2 = AstConv::ast_region_to_region(&icx, bound, None);
1480 let pred = ty::Binder::bind(ty::OutlivesPredicate(r1, r2));
1481 predicates.push(ty::Predicate::RegionOutlives(pred))
1485 &hir::WherePredicate::EqPredicate(..) => {
1491 // Add predicates from associated type bounds.
1492 if let Some((self_trait_ref, trait_items)) = is_trait {
1493 predicates.extend(trait_items.iter().flat_map(|trait_item_ref| {
1494 let trait_item = tcx.hir.trait_item(trait_item_ref.id);
1495 let bounds = match trait_item.node {
1496 hir::TraitItemKind::Type(ref bounds, _) => bounds,
1498 return vec![].into_iter();
1502 let assoc_ty = tcx.mk_projection(
1503 tcx.hir.local_def_id(trait_item.id),
1504 self_trait_ref.substs,
1507 let bounds = compute_bounds(&ItemCtxt::new(tcx, def_id),
1510 SizedByDefault::Yes,
1513 bounds.predicates(tcx, assoc_ty).into_iter()
1517 // Subtle: before we store the predicates into the tcx, we
1518 // sort them so that predicates like `T: Foo<Item=U>` come
1519 // before uses of `U`. This avoids false ambiguity errors
1520 // in trait checking. See `setup_constraining_predicates`
1522 if let NodeItem(&Item { node: ItemImpl(..), .. }) = node {
1523 let self_ty = tcx.type_of(def_id);
1524 let trait_ref = tcx.impl_trait_ref(def_id);
1525 ctp::setup_constraining_predicates(tcx,
1528 &mut ctp::parameters_for_impl(self_ty, trait_ref));
1531 ty::GenericPredicates {
1532 parent: generics.parent,
1537 pub enum SizedByDefault { Yes, No, }
1539 /// Translate the AST's notion of ty param bounds (which are an enum consisting of a newtyped Ty or
1540 /// a region) to ty's notion of ty param bounds, which can either be user-defined traits, or the
1541 /// built-in trait (formerly known as kind): Send.
1542 pub fn compute_bounds<'gcx: 'tcx, 'tcx>(astconv: &AstConv<'gcx, 'tcx>,
1544 ast_bounds: &[hir::TyParamBound],
1545 sized_by_default: SizedByDefault,
1549 let mut region_bounds = vec![];
1550 let mut trait_bounds = vec![];
1551 for ast_bound in ast_bounds {
1553 hir::TraitTyParamBound(ref b, hir::TraitBoundModifier::None) => {
1554 trait_bounds.push(b);
1556 hir::TraitTyParamBound(_, hir::TraitBoundModifier::Maybe) => {}
1557 hir::RegionTyParamBound(ref l) => {
1558 region_bounds.push(l);
1563 let mut projection_bounds = vec![];
1565 let mut trait_bounds: Vec<_> = trait_bounds.iter().map(|&bound| {
1566 astconv.instantiate_poly_trait_ref(bound,
1568 &mut projection_bounds)
1571 let region_bounds = region_bounds.into_iter().map(|r| {
1572 astconv.ast_region_to_region(r, None)
1575 trait_bounds.sort_by(|a,b| a.def_id().cmp(&b.def_id()));
1577 let implicitly_sized = if let SizedByDefault::Yes = sized_by_default {
1578 !is_unsized(astconv, ast_bounds, span)
1591 /// Converts a specific TyParamBound from the AST into a set of
1592 /// predicates that apply to the self-type. A vector is returned
1593 /// because this can be anywhere from 0 predicates (`T:?Sized` adds no
1594 /// predicates) to 1 (`T:Foo`) to many (`T:Bar<X=i32>` adds `T:Bar`
1595 /// and `<T as Bar>::X == i32`).
1596 fn predicates_from_bound<'tcx>(astconv: &AstConv<'tcx, 'tcx>,
1598 bound: &hir::TyParamBound)
1599 -> Vec<ty::Predicate<'tcx>>
1602 hir::TraitTyParamBound(ref tr, hir::TraitBoundModifier::None) => {
1603 let mut projections = Vec::new();
1604 let pred = astconv.instantiate_poly_trait_ref(tr,
1607 projections.into_iter()
1608 .map(|p| p.to_predicate())
1609 .chain(Some(pred.to_predicate()))
1612 hir::RegionTyParamBound(ref lifetime) => {
1613 let region = astconv.ast_region_to_region(lifetime, None);
1614 let pred = ty::Binder::bind(ty::OutlivesPredicate(param_ty, region));
1615 vec![ty::Predicate::TypeOutlives(pred)]
1617 hir::TraitTyParamBound(_, hir::TraitBoundModifier::Maybe) => {
1623 fn compute_sig_of_foreign_fn_decl<'a, 'tcx>(
1624 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1628 -> ty::PolyFnSig<'tcx>
1630 let fty = AstConv::ty_of_fn(&ItemCtxt::new(tcx, def_id), hir::Unsafety::Unsafe, abi, decl);
1632 // feature gate SIMD types in FFI, since I (huonw) am not sure the
1633 // ABIs are handled at all correctly.
1634 if abi != abi::Abi::RustIntrinsic && abi != abi::Abi::PlatformIntrinsic
1635 && !tcx.features().simd_ffi {
1636 let check = |ast_ty: &hir::Ty, ty: Ty| {
1638 tcx.sess.struct_span_err(ast_ty.span,
1639 &format!("use of SIMD type `{}` in FFI is highly experimental and \
1640 may result in invalid code",
1641 tcx.hir.node_to_pretty_string(ast_ty.id)))
1642 .help("add #![feature(simd_ffi)] to the crate attributes to enable")
1646 for (input, ty) in decl.inputs.iter().zip(*fty.inputs().skip_binder()) {
1649 if let hir::Return(ref ty) = decl.output {
1650 check(&ty, *fty.output().skip_binder())
1657 fn is_foreign_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1660 match tcx.hir.get_if_local(def_id) {
1661 Some(hir_map::NodeForeignItem(..)) => true,
1663 _ => bug!("is_foreign_item applied to non-local def-id {:?}", def_id)
1667 fn from_target_feature(
1670 attr: &ast::Attribute,
1671 whitelist: &FxHashMap<String, Option<String>>,
1672 target_features: &mut Vec<Symbol>,
1674 let list = match attr.meta_item_list() {
1677 let msg = "#[target_feature] attribute must be of the form \
1678 #[target_feature(..)]";
1679 tcx.sess.span_err(attr.span, &msg);
1683 let rust_features = tcx.features();
1685 // Only `enable = ...` is accepted in the meta item list
1686 if !item.check_name("enable") {
1687 let msg = "#[target_feature(..)] only accepts sub-keys of `enable` \
1689 tcx.sess.span_err(item.span, &msg);
1693 // Must be of the form `enable = "..."` ( a string)
1694 let value = match item.value_str() {
1695 Some(value) => value,
1697 let msg = "#[target_feature] attribute must be of the form \
1698 #[target_feature(enable = \"..\")]";
1699 tcx.sess.span_err(item.span, &msg);
1704 // We allow comma separation to enable multiple features
1705 for feature in value.as_str().split(',') {
1707 // Only allow whitelisted features per platform
1708 let feature_gate = match whitelist.get(feature) {
1711 let msg = format!("the feature named `{}` is not valid for \
1712 this target", feature);
1713 let mut err = tcx.sess.struct_span_err(item.span, &msg);
1715 if feature.starts_with("+") {
1716 let valid = whitelist.contains_key(&feature[1..]);
1718 err.help("consider removing the leading `+` in the feature name");
1726 // Only allow features whose feature gates have been enabled
1727 let allowed = match feature_gate.as_ref().map(|s| &**s) {
1728 Some("arm_target_feature") => rust_features.arm_target_feature,
1729 Some("aarch64_target_feature") => rust_features.aarch64_target_feature,
1730 Some("hexagon_target_feature") => rust_features.hexagon_target_feature,
1731 Some("powerpc_target_feature") => rust_features.powerpc_target_feature,
1732 Some("mips_target_feature") => rust_features.mips_target_feature,
1733 Some("avx512_target_feature") => rust_features.avx512_target_feature,
1734 Some("mmx_target_feature") => rust_features.mmx_target_feature,
1735 Some("sse4a_target_feature") => rust_features.sse4a_target_feature,
1736 Some("tbm_target_feature") => rust_features.tbm_target_feature,
1737 Some(name) => bug!("unknown target feature gate {}", name),
1740 if !allowed && id.is_local() {
1741 feature_gate::emit_feature_err(
1742 &tcx.sess.parse_sess,
1743 feature_gate.as_ref().unwrap(),
1745 feature_gate::GateIssue::Language,
1746 &format!("the target feature `{}` is currently unstable",
1751 target_features.push(Symbol::intern(feature));
1756 fn linkage_by_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId, name: &str) -> Linkage {
1757 use rustc::mir::mono::Linkage::*;
1759 // Use the names from src/llvm/docs/LangRef.rst here. Most types are only
1760 // applicable to variable declarations and may not really make sense for
1761 // Rust code in the first place but whitelist them anyway and trust that
1762 // the user knows what s/he's doing. Who knows, unanticipated use cases
1763 // may pop up in the future.
1765 // ghost, dllimport, dllexport and linkonce_odr_autohide are not supported
1766 // and don't have to be, LLVM treats them as no-ops.
1768 "appending" => Appending,
1769 "available_externally" => AvailableExternally,
1771 "extern_weak" => ExternalWeak,
1772 "external" => External,
1773 "internal" => Internal,
1774 "linkonce" => LinkOnceAny,
1775 "linkonce_odr" => LinkOnceODR,
1776 "private" => Private,
1778 "weak_odr" => WeakODR,
1780 let span = tcx.hir.span_if_local(def_id);
1781 if let Some(span) = span {
1782 tcx.sess.span_fatal(span, "invalid linkage specified")
1784 tcx.sess.fatal(&format!("invalid linkage specified: {}", name))
1790 fn codegen_fn_attrs<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, id: DefId) -> CodegenFnAttrs {
1791 let attrs = tcx.get_attrs(id);
1793 let mut codegen_fn_attrs = CodegenFnAttrs::new();
1795 let whitelist = tcx.target_features_whitelist(LOCAL_CRATE);
1797 let mut inline_span = None;
1798 for attr in attrs.iter() {
1799 if attr.check_name("cold") {
1800 codegen_fn_attrs.flags |= CodegenFnAttrFlags::COLD;
1801 } else if attr.check_name("allocator") {
1802 codegen_fn_attrs.flags |= CodegenFnAttrFlags::ALLOCATOR;
1803 } else if attr.check_name("unwind") {
1804 codegen_fn_attrs.flags |= CodegenFnAttrFlags::UNWIND;
1805 } else if attr.check_name("rustc_allocator_nounwind") {
1806 codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_ALLOCATOR_NOUNWIND;
1807 } else if attr.check_name("naked") {
1808 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NAKED;
1809 } else if attr.check_name("no_mangle") {
1810 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_MANGLE;
1811 } else if attr.check_name("rustc_std_internal_symbol") {
1812 codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL;
1813 } else if attr.check_name("no_debug") {
1814 codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_DEBUG;
1815 } else if attr.check_name("inline") {
1816 codegen_fn_attrs.inline = attrs.iter().fold(InlineAttr::None, |ia, attr| {
1817 if attr.path != "inline" {
1820 let meta = match attr.meta() {
1821 Some(meta) => meta.node,
1825 MetaItemKind::Word => {
1829 MetaItemKind::List(ref items) => {
1831 inline_span = Some(attr.span);
1832 if items.len() != 1 {
1833 span_err!(tcx.sess.diagnostic(), attr.span, E0534,
1834 "expected one argument");
1836 } else if list_contains_name(&items[..], "always") {
1838 } else if list_contains_name(&items[..], "never") {
1841 span_err!(tcx.sess.diagnostic(), items[0].span, E0535,
1842 "invalid argument");
1850 } else if attr.check_name("export_name") {
1851 if let s @ Some(_) = attr.value_str() {
1852 codegen_fn_attrs.export_name = s;
1854 struct_span_err!(tcx.sess, attr.span, E0558,
1855 "export_name attribute has invalid format")
1856 .span_label(attr.span, "did you mean #[export_name=\"*\"]?")
1859 } else if attr.check_name("target_feature") {
1860 if tcx.fn_sig(id).unsafety() == Unsafety::Normal {
1861 let msg = "#[target_feature(..)] can only be applied to \
1863 tcx.sess.span_err(attr.span, msg);
1865 from_target_feature(tcx, id, attr, &whitelist, &mut codegen_fn_attrs.target_features);
1866 } else if attr.check_name("linkage") {
1867 if let Some(val) = attr.value_str() {
1868 codegen_fn_attrs.linkage = Some(linkage_by_name(tcx, id, &val.as_str()));
1873 // If a function uses #[target_feature] it can't be inlined into general
1874 // purpose functions as they wouldn't have the right target features
1875 // enabled. For that reason we also forbid #[inline(always)] as it can't be
1877 if codegen_fn_attrs.target_features.len() > 0 {
1878 if codegen_fn_attrs.inline == InlineAttr::Always {
1879 if let Some(span) = inline_span {
1880 tcx.sess.span_err(span, "cannot use #[inline(always)] with \
1881 #[target_feature]");