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::maps::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, TransFnAttrs, TransFnAttrFlags, 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_ty(&mut self, ty: &'tcx hir::Ty) {
135 if let hir::TyImplTraitExistential(..) = ty.node {
136 let def_id = self.tcx.hir.local_def_id(ty.id);
137 self.tcx.generics_of(def_id);
138 self.tcx.predicates_of(def_id);
140 intravisit::walk_ty(self, ty);
143 fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem) {
144 convert_trait_item(self.tcx, trait_item.id);
145 intravisit::walk_trait_item(self, trait_item);
148 fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem) {
149 convert_impl_item(self.tcx, impl_item.id);
150 intravisit::walk_impl_item(self, impl_item);
154 ///////////////////////////////////////////////////////////////////////////
155 // Utility types and common code for the above passes.
157 impl<'a, 'tcx> ItemCtxt<'a, 'tcx> {
158 pub fn new(tcx: TyCtxt<'a, 'tcx, 'tcx>, item_def_id: DefId)
159 -> ItemCtxt<'a,'tcx> {
167 impl<'a,'tcx> ItemCtxt<'a,'tcx> {
168 pub fn to_ty(&self, ast_ty: &hir::Ty) -> Ty<'tcx> {
169 AstConv::ast_ty_to_ty(self, ast_ty)
173 impl<'a, 'tcx> AstConv<'tcx, 'tcx> for ItemCtxt<'a, 'tcx> {
174 fn tcx<'b>(&'b self) -> TyCtxt<'b, 'tcx, 'tcx> { self.tcx }
176 fn get_type_parameter_bounds(&self,
179 -> ty::GenericPredicates<'tcx>
181 self.tcx.at(span).type_param_predicates((self.item_def_id, def_id))
184 fn re_infer(&self, _span: Span, _def: Option<&ty::RegionParameterDef>)
185 -> Option<ty::Region<'tcx>> {
189 fn ty_infer(&self, span: Span) -> Ty<'tcx> {
194 "the type placeholder `_` is not allowed within types on item signatures"
195 ).span_label(span, "not allowed in type signatures")
200 fn projected_ty_from_poly_trait_ref(&self,
203 poly_trait_ref: ty::PolyTraitRef<'tcx>)
206 if let Some(trait_ref) = poly_trait_ref.no_late_bound_regions() {
207 self.tcx().mk_projection(item_def_id, trait_ref.substs)
209 // no late-bound regions, we can just ignore the binder
210 span_err!(self.tcx().sess, span, E0212,
211 "cannot extract an associated type from a higher-ranked trait bound \
217 fn normalize_ty(&self, _span: Span, ty: Ty<'tcx>) -> Ty<'tcx> {
218 // types in item signatures are not normalized, to avoid undue
223 fn set_tainted_by_errors(&self) {
224 // no obvious place to track this, just let it go
227 fn record_ty(&self, _hir_id: hir::HirId, _ty: Ty<'tcx>, _span: Span) {
228 // no place to record types from signatures?
232 fn type_param_predicates<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
233 (item_def_id, def_id): (DefId, DefId))
234 -> ty::GenericPredicates<'tcx> {
235 use rustc::hir::map::*;
238 // In the AST, bounds can derive from two places. Either
239 // written inline like `<T:Foo>` or in a where clause like
242 let param_id = tcx.hir.as_local_node_id(def_id).unwrap();
243 let param_owner = tcx.hir.ty_param_owner(param_id);
244 let param_owner_def_id = tcx.hir.local_def_id(param_owner);
245 let generics = tcx.generics_of(param_owner_def_id);
246 let index = generics.type_param_to_index[&def_id];
247 let ty = tcx.mk_param(index, tcx.hir.ty_param_name(param_id).as_str());
249 // Don't look for bounds where the type parameter isn't in scope.
250 let parent = if item_def_id == param_owner_def_id {
253 tcx.generics_of(item_def_id).parent
256 let mut result = parent.map_or(ty::GenericPredicates {
260 let icx = ItemCtxt::new(tcx, parent);
261 icx.get_type_parameter_bounds(DUMMY_SP, def_id)
264 let item_node_id = tcx.hir.as_local_node_id(item_def_id).unwrap();
265 let ast_generics = match tcx.hir.get(item_node_id) {
266 NodeTraitItem(item) => &item.generics,
268 NodeImplItem(item) => &item.generics,
272 ItemFn(.., ref generics, _) |
273 ItemImpl(_, _, _, ref generics, ..) |
274 ItemTy(_, ref generics) |
275 ItemEnum(_, ref generics) |
276 ItemStruct(_, ref generics) |
277 ItemUnion(_, ref generics) => generics,
278 ItemTrait(_, _, ref generics, ..) => {
279 // Implied `Self: Trait` and supertrait bounds.
280 if param_id == item_node_id {
281 result.predicates.push(ty::TraitRef {
283 substs: Substs::identity_for_item(tcx, item_def_id)
292 NodeForeignItem(item) => {
294 ForeignItemFn(_, _, ref generics) => generics,
302 let icx = ItemCtxt::new(tcx, item_def_id);
303 result.predicates.extend(
304 icx.type_parameter_bounds_in_generics(ast_generics, param_id, ty));
308 impl<'a, 'tcx> ItemCtxt<'a, 'tcx> {
309 /// Find bounds from hir::Generics. This requires scanning through the
310 /// AST. We do this to avoid having to convert *all* the bounds, which
311 /// would create artificial cycles. Instead we can only convert the
312 /// bounds for a type parameter `X` if `X::Foo` is used.
313 fn type_parameter_bounds_in_generics(&self,
314 ast_generics: &hir::Generics,
315 param_id: ast::NodeId,
317 -> Vec<ty::Predicate<'tcx>>
320 ast_generics.ty_params()
321 .filter(|p| p.id == param_id)
322 .flat_map(|p| p.bounds.iter())
323 .flat_map(|b| predicates_from_bound(self, ty, b));
325 let from_where_clauses =
326 ast_generics.where_clause
329 .filter_map(|wp| match *wp {
330 hir::WherePredicate::BoundPredicate(ref bp) => Some(bp),
333 .filter(|bp| is_param(self.tcx, &bp.bounded_ty, param_id))
334 .flat_map(|bp| bp.bounds.iter())
335 .flat_map(|b| predicates_from_bound(self, ty, b));
337 from_ty_params.chain(from_where_clauses).collect()
341 /// Tests whether this is the AST for a reference to the type
342 /// parameter with id `param_id`. We use this so as to avoid running
343 /// `ast_ty_to_ty`, because we want to avoid triggering an all-out
344 /// conversion of the type to avoid inducing unnecessary cycles.
345 fn is_param<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
347 param_id: ast::NodeId)
350 if let hir::TyPath(hir::QPath::Resolved(None, ref path)) = ast_ty.node {
352 Def::SelfTy(Some(def_id), None) |
353 Def::TyParam(def_id) => {
354 def_id == tcx.hir.local_def_id(param_id)
363 fn convert_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, item_id: ast::NodeId) {
364 let it = tcx.hir.expect_item(item_id);
365 debug!("convert: item {} with id {}", it.name, it.id);
366 let def_id = tcx.hir.local_def_id(item_id);
368 // These don't define types.
369 hir::ItemExternCrate(_) |
372 hir::ItemGlobalAsm(_) => {}
373 hir::ItemForeignMod(ref foreign_mod) => {
374 for item in &foreign_mod.items {
375 let def_id = tcx.hir.local_def_id(item.id);
376 tcx.generics_of(def_id);
378 tcx.predicates_of(def_id);
379 if let hir::ForeignItemFn(..) = item.node {
384 hir::ItemEnum(ref enum_definition, _) => {
385 tcx.generics_of(def_id);
387 tcx.predicates_of(def_id);
388 convert_enum_variant_types(tcx, def_id, &enum_definition.variants);
390 hir::ItemImpl(..) => {
391 tcx.generics_of(def_id);
393 tcx.impl_trait_ref(def_id);
394 tcx.predicates_of(def_id);
396 hir::ItemTrait(..) => {
397 tcx.generics_of(def_id);
398 tcx.trait_def(def_id);
399 tcx.at(it.span).super_predicates_of(def_id);
400 tcx.predicates_of(def_id);
402 hir::ItemTraitAlias(..) => {
403 span_err!(tcx.sess, it.span, E0645,
404 "trait aliases are not yet implemented (see issue #41517)");
406 hir::ItemStruct(ref struct_def, _) |
407 hir::ItemUnion(ref struct_def, _) => {
408 tcx.generics_of(def_id);
410 tcx.predicates_of(def_id);
412 for f in struct_def.fields() {
413 let def_id = tcx.hir.local_def_id(f.id);
414 tcx.generics_of(def_id);
416 tcx.predicates_of(def_id);
419 if !struct_def.is_struct() {
420 convert_variant_ctor(tcx, struct_def.id());
423 hir::ItemTy(..) | hir::ItemStatic(..) | hir::ItemConst(..) | hir::ItemFn(..) => {
424 tcx.generics_of(def_id);
426 tcx.predicates_of(def_id);
427 if let hir::ItemFn(..) = it.node {
434 fn convert_trait_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, trait_item_id: ast::NodeId) {
435 let trait_item = tcx.hir.expect_trait_item(trait_item_id);
436 let def_id = tcx.hir.local_def_id(trait_item.id);
437 tcx.generics_of(def_id);
439 match trait_item.node {
440 hir::TraitItemKind::Const(..) |
441 hir::TraitItemKind::Type(_, Some(_)) |
442 hir::TraitItemKind::Method(..) => {
444 if let hir::TraitItemKind::Method(..) = trait_item.node {
449 hir::TraitItemKind::Type(_, None) => {}
452 tcx.predicates_of(def_id);
455 fn convert_impl_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, impl_item_id: ast::NodeId) {
456 let def_id = tcx.hir.local_def_id(impl_item_id);
457 tcx.generics_of(def_id);
459 tcx.predicates_of(def_id);
460 if let hir::ImplItemKind::Method(..) = tcx.hir.expect_impl_item(impl_item_id).node {
465 fn convert_variant_ctor<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
466 ctor_id: ast::NodeId) {
467 let def_id = tcx.hir.local_def_id(ctor_id);
468 tcx.generics_of(def_id);
470 tcx.predicates_of(def_id);
473 fn convert_enum_variant_types<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
475 variants: &[hir::Variant]) {
476 let def = tcx.adt_def(def_id);
477 let repr_type = def.repr.discr_type();
478 let initial = repr_type.initial_discriminant(tcx);
479 let mut prev_discr = None::<Discr<'tcx>>;
481 // fill the discriminant values and field types
482 for variant in variants {
483 let wrapped_discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
484 prev_discr = Some(if let Some(e) = variant.node.disr_expr {
485 let expr_did = tcx.hir.local_def_id(e.node_id);
486 def.eval_explicit_discr(tcx, expr_did)
487 } else if let Some(discr) = repr_type.disr_incr(tcx, prev_discr) {
490 struct_span_err!(tcx.sess, variant.span, E0370,
491 "enum discriminant overflowed")
492 .span_label(variant.span, format!("overflowed on value after {}",
493 prev_discr.unwrap()))
494 .note(&format!("explicitly set `{} = {}` if that is desired outcome",
495 variant.node.name, wrapped_discr))
498 }.unwrap_or(wrapped_discr));
500 for f in variant.node.data.fields() {
501 let def_id = tcx.hir.local_def_id(f.id);
502 tcx.generics_of(def_id);
504 tcx.predicates_of(def_id);
507 // Convert the ctor, if any. This also registers the variant as
509 convert_variant_ctor(tcx, variant.node.data.id());
513 fn convert_struct_variant<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
516 discr: ty::VariantDiscr,
517 def: &hir::VariantData)
519 let mut seen_fields: FxHashMap<ast::Ident, Span> = FxHashMap();
520 let node_id = tcx.hir.as_local_node_id(did).unwrap();
521 let fields = def.fields().iter().map(|f| {
522 let fid = tcx.hir.local_def_id(f.id);
523 let dup_span = seen_fields.get(&f.name.to_ident()).cloned();
524 if let Some(prev_span) = dup_span {
525 struct_span_err!(tcx.sess, f.span, E0124,
526 "field `{}` is already declared",
528 .span_label(f.span, "field already declared")
529 .span_label(prev_span, format!("`{}` first declared here", f.name))
532 seen_fields.insert(f.name.to_ident(), f.span);
538 vis: ty::Visibility::from_hir(&f.vis, node_id, tcx)
546 ctor_kind: CtorKind::from_hir(def),
550 fn adt_def<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
552 -> &'tcx ty::AdtDef {
553 use rustc::hir::map::*;
556 let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
557 let item = match tcx.hir.get(node_id) {
558 NodeItem(item) => item,
562 let repr = ReprOptions::new(tcx, def_id);
563 let (kind, variants) = match item.node {
564 ItemEnum(ref def, _) => {
565 let mut distance_from_explicit = 0;
566 (AdtKind::Enum, def.variants.iter().map(|v| {
567 let did = tcx.hir.local_def_id(v.node.data.id());
568 let discr = if let Some(e) = v.node.disr_expr {
569 distance_from_explicit = 0;
570 ty::VariantDiscr::Explicit(tcx.hir.local_def_id(e.node_id))
572 ty::VariantDiscr::Relative(distance_from_explicit)
574 distance_from_explicit += 1;
576 convert_struct_variant(tcx, did, v.node.name, discr, &v.node.data)
579 ItemStruct(ref def, _) => {
580 // Use separate constructor id for unit/tuple structs and reuse did for braced structs.
581 let ctor_id = if !def.is_struct() {
582 Some(tcx.hir.local_def_id(def.id()))
586 (AdtKind::Struct, vec![
587 convert_struct_variant(tcx, ctor_id.unwrap_or(def_id), item.name,
588 ty::VariantDiscr::Relative(0), def)
591 ItemUnion(ref def, _) => {
592 (AdtKind::Union, vec![
593 convert_struct_variant(tcx, def_id, item.name,
594 ty::VariantDiscr::Relative(0), def)
599 tcx.alloc_adt_def(def_id, kind, variants, repr)
602 /// Ensures that the super-predicates of the trait with def-id
603 /// trait_def_id are converted and stored. This also ensures that
604 /// the transitive super-predicates are converted;
605 fn super_predicates_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
607 -> ty::GenericPredicates<'tcx> {
608 debug!("super_predicates(trait_def_id={:?})", trait_def_id);
609 let trait_node_id = tcx.hir.as_local_node_id(trait_def_id).unwrap();
611 let item = match tcx.hir.get(trait_node_id) {
612 hir_map::NodeItem(item) => item,
613 _ => bug!("trait_node_id {} is not an item", trait_node_id)
616 let (generics, bounds) = match item.node {
617 hir::ItemTrait(.., ref generics, ref supertraits, _) => (generics, supertraits),
618 hir::ItemTraitAlias(ref generics, ref supertraits) => (generics, supertraits),
619 _ => span_bug!(item.span,
620 "super_predicates invoked on non-trait"),
623 let icx = ItemCtxt::new(tcx, trait_def_id);
625 // Convert the bounds that follow the colon, e.g. `Bar+Zed` in `trait Foo : Bar+Zed`.
626 let self_param_ty = tcx.mk_self_type();
627 let superbounds1 = compute_bounds(&icx,
633 let superbounds1 = superbounds1.predicates(tcx, self_param_ty);
635 // Convert any explicit superbounds in the where clause,
636 // e.g. `trait Foo where Self : Bar`:
637 let superbounds2 = icx.type_parameter_bounds_in_generics(generics, item.id, self_param_ty);
639 // Combine the two lists to form the complete set of superbounds:
640 let superbounds: Vec<_> = superbounds1.into_iter().chain(superbounds2).collect();
642 // Now require that immediate supertraits are converted,
643 // which will, in turn, reach indirect supertraits.
644 for bound in superbounds.iter().filter_map(|p| p.to_opt_poly_trait_ref()) {
645 tcx.at(item.span).super_predicates_of(bound.def_id());
648 ty::GenericPredicates {
650 predicates: superbounds
654 fn trait_def<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
656 -> &'tcx ty::TraitDef {
657 let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
658 let item = tcx.hir.expect_item(node_id);
660 let (is_auto, unsafety) = match item.node {
661 hir::ItemTrait(is_auto, unsafety, ..) => (is_auto == hir::IsAuto::Yes, unsafety),
662 hir::ItemTraitAlias(..) => (false, hir::Unsafety::Normal),
663 _ => span_bug!(item.span, "trait_def_of_item invoked on non-trait"),
666 let paren_sugar = tcx.has_attr(def_id, "rustc_paren_sugar");
667 if paren_sugar && !tcx.features().unboxed_closures {
668 let mut err = tcx.sess.struct_span_err(
670 "the `#[rustc_paren_sugar]` attribute is a temporary means of controlling \
671 which traits can use parenthetical notation");
673 "add `#![feature(unboxed_closures)]` to \
674 the crate attributes to use it");
678 let def_path_hash = tcx.def_path_hash(def_id);
679 let def = ty::TraitDef::new(def_id,
684 tcx.alloc_trait_def(def)
687 fn has_late_bound_regions<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
688 node: hir_map::Node<'tcx>)
690 struct LateBoundRegionsDetector<'a, 'tcx: 'a> {
691 tcx: TyCtxt<'a, 'tcx, 'tcx>,
693 has_late_bound_regions: Option<Span>,
696 impl<'a, 'tcx> Visitor<'tcx> for LateBoundRegionsDetector<'a, 'tcx> {
697 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
698 NestedVisitorMap::None
701 fn visit_ty(&mut self, ty: &'tcx hir::Ty) {
702 if self.has_late_bound_regions.is_some() { return }
704 hir::TyBareFn(..) => {
705 self.binder_depth += 1;
706 intravisit::walk_ty(self, ty);
707 self.binder_depth -= 1;
709 _ => intravisit::walk_ty(self, ty)
713 fn visit_poly_trait_ref(&mut self,
714 tr: &'tcx hir::PolyTraitRef,
715 m: hir::TraitBoundModifier) {
716 if self.has_late_bound_regions.is_some() { return }
717 self.binder_depth += 1;
718 intravisit::walk_poly_trait_ref(self, tr, m);
719 self.binder_depth -= 1;
722 fn visit_lifetime(&mut self, lt: &'tcx hir::Lifetime) {
723 if self.has_late_bound_regions.is_some() { return }
725 let hir_id = self.tcx.hir.node_to_hir_id(lt.id);
726 match self.tcx.named_region(hir_id) {
727 Some(rl::Region::Static) | Some(rl::Region::EarlyBound(..)) => {}
728 Some(rl::Region::LateBound(debruijn, _, _)) |
729 Some(rl::Region::LateBoundAnon(debruijn, _))
730 if debruijn.depth < self.binder_depth => {}
731 _ => self.has_late_bound_regions = Some(lt.span),
736 fn has_late_bound_regions<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
737 generics: &'tcx hir::Generics,
738 decl: &'tcx hir::FnDecl)
740 let mut visitor = LateBoundRegionsDetector {
741 tcx, binder_depth: 1, has_late_bound_regions: None
743 for lifetime in generics.lifetimes() {
744 let hir_id = tcx.hir.node_to_hir_id(lifetime.lifetime.id);
745 if tcx.is_late_bound(hir_id) {
746 return Some(lifetime.lifetime.span);
749 visitor.visit_fn_decl(decl);
750 visitor.has_late_bound_regions
754 hir_map::NodeTraitItem(item) => match item.node {
755 hir::TraitItemKind::Method(ref sig, _) =>
756 has_late_bound_regions(tcx, &item.generics, &sig.decl),
759 hir_map::NodeImplItem(item) => match item.node {
760 hir::ImplItemKind::Method(ref sig, _) =>
761 has_late_bound_regions(tcx, &item.generics, &sig.decl),
764 hir_map::NodeForeignItem(item) => match item.node {
765 hir::ForeignItemFn(ref fn_decl, _, ref generics) =>
766 has_late_bound_regions(tcx, generics, fn_decl),
769 hir_map::NodeItem(item) => match item.node {
770 hir::ItemFn(ref fn_decl, .., ref generics, _) =>
771 has_late_bound_regions(tcx, generics, fn_decl),
778 fn generics_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
780 -> &'tcx ty::Generics {
781 use rustc::hir::map::*;
784 let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
786 let node = tcx.hir.get(node_id);
787 let parent_def_id = match node {
793 let parent_id = tcx.hir.get_parent(node_id);
794 Some(tcx.hir.local_def_id(parent_id))
796 NodeExpr(&hir::Expr { node: hir::ExprClosure(..), .. }) => {
797 Some(tcx.closure_base_def_id(def_id))
799 NodeTy(&hir::Ty { node: hir::TyImplTraitExistential(..), .. }) => {
800 let mut parent_id = node_id;
802 match tcx.hir.get(parent_id) {
803 NodeItem(_) | NodeImplItem(_) | NodeTraitItem(_) => break,
805 parent_id = tcx.hir.get_parent_node(parent_id);
809 Some(tcx.hir.local_def_id(parent_id))
814 let mut opt_self = None;
815 let mut allow_defaults = false;
817 let no_generics = hir::Generics::empty();
818 let ast_generics = match node {
819 NodeTraitItem(item) => &item.generics,
821 NodeImplItem(item) => &item.generics,
825 ItemFn(.., ref generics, _) |
826 ItemImpl(_, _, _, ref generics, ..) => generics,
828 ItemTy(_, ref generics) |
829 ItemEnum(_, ref generics) |
830 ItemStruct(_, ref generics) |
831 ItemUnion(_, ref generics) => {
832 allow_defaults = true;
836 ItemTrait(_, _, ref generics, ..) | ItemTraitAlias(ref generics, ..) => {
837 // Add in the self type parameter.
839 // Something of a hack: use the node id for the trait, also as
840 // the node id for the Self type parameter.
841 let param_id = item.id;
843 opt_self = Some(ty::TypeParameterDef {
845 name: keywords::SelfType.name().as_str(),
846 def_id: tcx.hir.local_def_id(param_id),
848 object_lifetime_default: rl::Set1::Empty,
849 pure_wrt_drop: false,
853 allow_defaults = true;
861 NodeForeignItem(item) => {
863 ForeignItemStatic(..) => &no_generics,
864 ForeignItemFn(_, _, ref generics) => generics,
865 ForeignItemType => &no_generics,
869 NodeTy(&hir::Ty { node: hir::TyImplTraitExistential(ref exist_ty, _), .. }) => {
876 let has_self = opt_self.is_some();
877 let mut parent_has_self = false;
878 let mut own_start = has_self as u32;
879 let (parent_regions, parent_types) = parent_def_id.map_or((0, 0), |def_id| {
880 let generics = tcx.generics_of(def_id);
881 assert_eq!(has_self, false);
882 parent_has_self = generics.has_self;
883 own_start = generics.count() as u32;
884 (generics.parent_regions + generics.regions.len() as u32,
885 generics.parent_types + generics.types.len() as u32)
888 let early_lifetimes = early_bound_lifetimes_from_generics(tcx, ast_generics);
889 let regions = early_lifetimes.enumerate().map(|(i, l)| {
890 ty::RegionParameterDef {
891 name: l.lifetime.name.name().as_str(),
892 index: own_start + i as u32,
893 def_id: tcx.hir.local_def_id(l.lifetime.id),
894 pure_wrt_drop: l.pure_wrt_drop,
896 }).collect::<Vec<_>>();
898 let hir_id = tcx.hir.node_to_hir_id(node_id);
899 let object_lifetime_defaults = tcx.object_lifetime_defaults(hir_id);
901 // Now create the real type parameters.
902 let type_start = own_start + regions.len() as u32;
903 let types = ast_generics.ty_params().enumerate().map(|(i, p)| {
904 if p.name == keywords::SelfType.name() {
905 span_bug!(p.span, "`Self` should not be the name of a regular parameter");
908 if !allow_defaults && p.default.is_some() {
909 if !tcx.features().default_type_parameter_fallback {
911 lint::builtin::INVALID_TYPE_PARAM_DEFAULT,
914 &format!("defaults for type parameters are only allowed in `struct`, \
915 `enum`, `type`, or `trait` definitions."));
919 ty::TypeParameterDef {
920 index: type_start + i as u32,
921 name: p.name.as_str(),
922 def_id: tcx.hir.local_def_id(p.id),
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 pure_wrt_drop: p.pure_wrt_drop,
927 synthetic: p.synthetic,
931 let mut types: Vec<_> = opt_self.into_iter().chain(types).collect();
933 // provide junk type parameter defs - the only place that
934 // cares about anything but the length is instantiation,
935 // and we don't do that for closures.
936 if let NodeExpr(&hir::Expr { node: hir::ExprClosure(..), .. }) = node {
937 // add a dummy parameter for the closure kind
938 types.push(ty::TypeParameterDef {
940 name: Symbol::intern("<closure_kind>").as_str(),
943 object_lifetime_default: rl::Set1::Empty,
944 pure_wrt_drop: false,
948 // add a dummy parameter for the closure signature
949 types.push(ty::TypeParameterDef {
950 index: type_start + 1,
951 name: Symbol::intern("<closure_signature>").as_str(),
954 object_lifetime_default: rl::Set1::Empty,
955 pure_wrt_drop: false,
959 tcx.with_freevars(node_id, |fv| {
960 types.extend(fv.iter().zip(2..).map(|(_, i)| ty::TypeParameterDef {
961 index: type_start + i,
962 name: Symbol::intern("<upvar>").as_str(),
965 object_lifetime_default: rl::Set1::Empty,
966 pure_wrt_drop: false,
972 let type_param_to_index = types.iter()
973 .map(|param| (param.def_id, param.index))
976 tcx.alloc_generics(ty::Generics {
977 parent: parent_def_id,
983 has_self: has_self || parent_has_self,
984 has_late_bound_regions: has_late_bound_regions(tcx, node),
988 fn type_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
991 use rustc::hir::map::*;
994 let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
996 let icx = ItemCtxt::new(tcx, def_id);
998 match tcx.hir.get(node_id) {
999 NodeTraitItem(item) => {
1001 TraitItemKind::Method(..) => {
1002 let substs = Substs::identity_for_item(tcx, def_id);
1003 tcx.mk_fn_def(def_id, substs)
1005 TraitItemKind::Const(ref ty, _) |
1006 TraitItemKind::Type(_, Some(ref ty)) => icx.to_ty(ty),
1007 TraitItemKind::Type(_, None) => {
1008 span_bug!(item.span, "associated type missing default");
1013 NodeImplItem(item) => {
1015 ImplItemKind::Method(..) => {
1016 let substs = Substs::identity_for_item(tcx, def_id);
1017 tcx.mk_fn_def(def_id, substs)
1019 ImplItemKind::Const(ref ty, _) => icx.to_ty(ty),
1020 ImplItemKind::Type(ref ty) => {
1021 if tcx.impl_trait_ref(tcx.hir.get_parent_did(node_id)).is_none() {
1022 span_err!(tcx.sess, item.span, E0202,
1023 "associated types are not allowed in inherent impls");
1033 ItemStatic(ref t, ..) | ItemConst(ref t, _) |
1034 ItemTy(ref t, _) | ItemImpl(.., ref t, _) => {
1038 let substs = Substs::identity_for_item(tcx, def_id);
1039 tcx.mk_fn_def(def_id, substs)
1044 let def = tcx.adt_def(def_id);
1045 let substs = Substs::identity_for_item(tcx, def_id);
1046 tcx.mk_adt(def, substs)
1048 ItemTrait(..) | ItemTraitAlias(..) |
1050 ItemForeignMod(..) |
1052 ItemExternCrate(..) |
1056 "compute_type_of_item: unexpected item type: {:?}",
1062 NodeForeignItem(foreign_item) => {
1063 match foreign_item.node {
1064 ForeignItemFn(..) => {
1065 let substs = Substs::identity_for_item(tcx, def_id);
1066 tcx.mk_fn_def(def_id, substs)
1068 ForeignItemStatic(ref t, _) => icx.to_ty(t),
1069 ForeignItemType => tcx.mk_foreign(def_id),
1073 NodeStructCtor(&ref def) |
1074 NodeVariant(&Spanned { node: hir::Variant_ { data: ref def, .. }, .. }) => {
1076 VariantData::Unit(..) | VariantData::Struct(..) => {
1077 tcx.type_of(tcx.hir.get_parent_did(node_id))
1079 VariantData::Tuple(..) => {
1080 let substs = Substs::identity_for_item(tcx, def_id);
1081 tcx.mk_fn_def(def_id, substs)
1086 NodeField(field) => icx.to_ty(&field.ty),
1088 NodeExpr(&hir::Expr { node: hir::ExprClosure(.., gen), .. }) => {
1090 let hir_id = tcx.hir.node_to_hir_id(node_id);
1091 return tcx.typeck_tables_of(def_id).node_id_to_type(hir_id);
1094 let substs = ty::ClosureSubsts {
1095 substs: Substs::for_item(
1099 let region = def.to_early_bound_region_data();
1100 tcx.mk_region(ty::ReEarlyBound(region))
1102 |def, _| tcx.mk_param_from_def(def)
1106 tcx.mk_closure(def_id, substs)
1109 NodeExpr(_) => match tcx.hir.get(tcx.hir.get_parent_node(node_id)) {
1110 NodeTy(&hir::Ty { node: TyArray(_, body), .. }) |
1111 NodeTy(&hir::Ty { node: TyTypeof(body), .. }) |
1112 NodeExpr(&hir::Expr { node: ExprRepeat(_, body), .. })
1113 if body.node_id == node_id => tcx.types.usize,
1115 NodeVariant(&Spanned { node: Variant_ { disr_expr: Some(e), .. }, .. })
1116 if e.node_id == node_id => {
1117 tcx.adt_def(tcx.hir.get_parent_did(node_id))
1118 .repr.discr_type().to_ty(tcx)
1122 bug!("unexpected expr parent in type_of_def_id(): {:?}", x);
1126 NodeTyParam(&hir::TyParam { default: Some(ref ty), .. }) => {
1130 NodeTy(&hir::Ty { node: TyImplTraitExistential(..), .. }) => {
1131 let owner = tcx.hir.get_parent_did(node_id);
1132 let hir_id = tcx.hir.node_to_hir_id(node_id);
1133 tcx.typeck_tables_of(owner).node_id_to_type(hir_id)
1137 bug!("unexpected sort of node in type_of_def_id(): {:?}", x);
1142 fn fn_sig<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1144 -> ty::PolyFnSig<'tcx> {
1145 use rustc::hir::map::*;
1148 let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
1150 let icx = ItemCtxt::new(tcx, def_id);
1152 match tcx.hir.get(node_id) {
1153 NodeTraitItem(&hir::TraitItem { node: TraitItemKind::Method(ref sig, _), .. }) |
1154 NodeImplItem(&hir::ImplItem { node: ImplItemKind::Method(ref sig, _), .. }) => {
1155 AstConv::ty_of_fn(&icx, sig.unsafety, sig.abi, &sig.decl)
1158 NodeItem(&hir::Item { node: ItemFn(ref decl, unsafety, _, abi, _, _), .. }) => {
1159 AstConv::ty_of_fn(&icx, unsafety, abi, decl)
1162 NodeForeignItem(&hir::ForeignItem { node: ForeignItemFn(ref fn_decl, _, _), .. }) => {
1163 let abi = tcx.hir.get_foreign_abi(node_id);
1164 compute_sig_of_foreign_fn_decl(tcx, def_id, fn_decl, abi)
1167 NodeStructCtor(&VariantData::Tuple(ref fields, _)) |
1168 NodeVariant(&Spanned { node: hir::Variant_ {
1169 data: VariantData::Tuple(ref fields, _), ..
1171 let ty = tcx.type_of(tcx.hir.get_parent_did(node_id));
1172 let inputs = fields.iter().map(|f| {
1173 tcx.type_of(tcx.hir.local_def_id(f.id))
1175 ty::Binder::bind(tcx.mk_fn_sig(
1179 hir::Unsafety::Normal,
1184 NodeExpr(&hir::Expr { node: hir::ExprClosure(..), .. }) => {
1185 // Closure signatures are not like other function
1186 // signatures and cannot be accessed through `fn_sig`. For
1187 // example, a closure signature excludes the `self`
1188 // argument. In any case they are embedded within the
1189 // closure type as part of the `ClosureSubsts`.
1192 // the signature of a closure, you should use the
1193 // `closure_sig` method on the `ClosureSubsts`:
1195 // closure_substs.closure_sig(def_id, tcx)
1197 // or, inside of an inference context, you can use
1199 // infcx.closure_sig(def_id, closure_substs)
1200 bug!("to get the signature of a closure, use `closure_sig()` not `fn_sig()`");
1204 bug!("unexpected sort of node in fn_sig(): {:?}", x);
1209 fn impl_trait_ref<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1211 -> Option<ty::TraitRef<'tcx>> {
1212 let icx = ItemCtxt::new(tcx, def_id);
1214 let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
1215 match tcx.hir.expect_item(node_id).node {
1216 hir::ItemImpl(.., ref opt_trait_ref, _, _) => {
1217 opt_trait_ref.as_ref().map(|ast_trait_ref| {
1218 let selfty = tcx.type_of(def_id);
1219 AstConv::instantiate_mono_trait_ref(&icx, ast_trait_ref, selfty)
1226 fn impl_polarity<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1228 -> hir::ImplPolarity {
1229 let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
1230 match tcx.hir.expect_item(node_id).node {
1231 hir::ItemImpl(_, polarity, ..) => polarity,
1232 ref item => bug!("impl_polarity: {:?} not an impl", item)
1236 // Is it marked with ?Sized
1237 fn is_unsized<'gcx: 'tcx, 'tcx>(astconv: &AstConv<'gcx, 'tcx>,
1238 ast_bounds: &[hir::TyParamBound],
1241 let tcx = astconv.tcx();
1243 // Try to find an unbound in bounds.
1244 let mut unbound = None;
1245 for ab in ast_bounds {
1246 if let &hir::TraitTyParamBound(ref ptr, hir::TraitBoundModifier::Maybe) = ab {
1247 if unbound.is_none() {
1248 unbound = Some(ptr.trait_ref.clone());
1250 span_err!(tcx.sess, span, E0203,
1251 "type parameter has more than one relaxed default \
1252 bound, only one is supported");
1257 let kind_id = tcx.lang_items().require(SizedTraitLangItem);
1260 // FIXME(#8559) currently requires the unbound to be built-in.
1261 if let Ok(kind_id) = kind_id {
1262 if tpb.path.def != Def::Trait(kind_id) {
1263 tcx.sess.span_warn(span,
1264 "default bound relaxed for a type parameter, but \
1265 this does nothing because the given bound is not \
1266 a default. Only `?Sized` is supported");
1270 _ if kind_id.is_ok() => {
1273 // No lang item for Sized, so we can't add it as a bound.
1280 /// Returns the early-bound lifetimes declared in this generics
1281 /// listing. For anything other than fns/methods, this is just all
1282 /// the lifetimes that are declared. For fns or methods, we have to
1283 /// screen out those that do not appear in any where-clauses etc using
1284 /// `resolve_lifetime::early_bound_lifetimes`.
1285 fn early_bound_lifetimes_from_generics<'a, 'tcx>(
1286 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1287 ast_generics: &'a hir::Generics)
1288 -> impl Iterator<Item=&'a hir::LifetimeDef> + Captures<'tcx>
1293 let hir_id = tcx.hir.node_to_hir_id(l.lifetime.id);
1294 !tcx.is_late_bound(hir_id)
1298 fn predicates_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1300 -> ty::GenericPredicates<'tcx> {
1301 let explicit = explicit_predicates_of(tcx, def_id);
1302 let predicates = if tcx.sess.features_untracked().infer_outlives_requirements {
1303 [&explicit.predicates[..], &tcx.inferred_outlives_of(def_id)[..]].concat()
1304 } else { explicit.predicates };
1306 ty::GenericPredicates {
1307 parent: explicit.parent,
1308 predicates: predicates,
1312 pub fn explicit_predicates_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1314 -> ty::GenericPredicates<'tcx> {
1315 use rustc::hir::map::*;
1318 debug!("explicit_predicates_of(def_id={:?})", def_id);
1320 let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
1321 let node = tcx.hir.get(node_id);
1323 let mut is_trait = None;
1324 let mut is_default_impl_trait = None;
1326 let icx = ItemCtxt::new(tcx, def_id);
1327 let no_generics = hir::Generics::empty();
1328 let ast_generics = match node {
1329 NodeTraitItem(item) => &item.generics,
1330 NodeImplItem(item) => &item.generics,
1334 ItemImpl(_, _, defaultness, ref generics, ..) => {
1335 if defaultness.is_default() {
1336 is_default_impl_trait = tcx.impl_trait_ref(def_id);
1340 ItemFn(.., ref generics, _) |
1341 ItemTy(_, ref generics) |
1342 ItemEnum(_, ref generics) |
1343 ItemStruct(_, ref generics) |
1344 ItemUnion(_, ref generics) => generics,
1346 ItemTrait(_, _, ref generics, .., ref items) => {
1347 is_trait = Some((ty::TraitRef {
1349 substs: Substs::identity_for_item(tcx, def_id)
1358 NodeForeignItem(item) => {
1360 ForeignItemStatic(..) => &no_generics,
1361 ForeignItemFn(_, _, ref generics) => generics,
1362 ForeignItemType => &no_generics,
1366 NodeTy(&Ty { node: TyImplTraitExistential(ref exist_ty, _), span, .. }) => {
1367 let substs = Substs::identity_for_item(tcx, def_id);
1368 let anon_ty = tcx.mk_anon(def_id, substs);
1370 debug!("explicit_predicates_of: anon_ty={:?}", anon_ty);
1372 // Collect the bounds, i.e. the `A+B+'c` in `impl A+B+'c`.
1373 let bounds = compute_bounds(&icx,
1376 SizedByDefault::Yes,
1379 debug!("explicit_predicates_of: bounds={:?}", bounds);
1381 let predicates = bounds.predicates(tcx, anon_ty);
1383 debug!("explicit_predicates_of: predicates={:?}", predicates);
1385 return ty::GenericPredicates {
1387 predicates: predicates
1394 let generics = tcx.generics_of(def_id);
1395 let parent_count = generics.parent_count() as u32;
1396 let has_own_self = generics.has_self && parent_count == 0;
1398 let mut predicates = vec![];
1400 // Below we'll consider the bounds on the type parameters (including `Self`)
1401 // and the explicit where-clauses, but to get the full set of predicates
1402 // on a trait we need to add in the supertrait bounds and bounds found on
1403 // associated types.
1404 if let Some((trait_ref, _)) = is_trait {
1405 predicates = tcx.super_predicates_of(def_id).predicates;
1407 // Add in a predicate that `Self:Trait` (where `Trait` is the
1408 // current trait). This is needed for builtin bounds.
1409 predicates.push(trait_ref.to_poly_trait_ref().to_predicate());
1412 // In default impls, we can assume that the self type implements
1413 // the trait. So in:
1415 // default impl Foo for Bar { .. }
1417 // we add a default where clause `Foo: Bar`. We do a similar thing for traits
1418 // (see below). Recall that a default impl is not itself an impl, but rather a
1419 // set of defaults that can be incorporated into another impl.
1420 if let Some(trait_ref) = is_default_impl_trait {
1421 predicates.push(trait_ref.to_poly_trait_ref().to_predicate());
1424 // Collect the region predicates that were declared inline as
1425 // well. In the case of parameters declared on a fn or method, we
1426 // have to be careful to only iterate over early-bound regions.
1427 let mut index = parent_count + has_own_self as u32;
1428 for param in early_bound_lifetimes_from_generics(tcx, ast_generics) {
1429 let region = tcx.mk_region(ty::ReEarlyBound(ty::EarlyBoundRegion {
1430 def_id: tcx.hir.local_def_id(param.lifetime.id),
1432 name: param.lifetime.name.name().as_str(),
1436 for bound in ¶m.bounds {
1437 let bound_region = AstConv::ast_region_to_region(&icx, bound, None);
1438 let outlives = ty::Binder::bind(ty::OutlivesPredicate(region, bound_region));
1439 predicates.push(outlives.to_predicate());
1443 // Collect the predicates that were written inline by the user on each
1444 // type parameter (e.g., `<T:Foo>`).
1445 for param in ast_generics.ty_params() {
1446 let param_ty = ty::ParamTy::new(index, param.name.as_str()).to_ty(tcx);
1449 let bounds = compute_bounds(&icx,
1452 SizedByDefault::Yes,
1454 predicates.extend(bounds.predicates(tcx, param_ty));
1457 // Add in the bounds that appear in the where-clause
1458 let where_clause = &ast_generics.where_clause;
1459 for predicate in &where_clause.predicates {
1461 &hir::WherePredicate::BoundPredicate(ref bound_pred) => {
1462 let ty = icx.to_ty(&bound_pred.bounded_ty);
1464 for bound in bound_pred.bounds.iter() {
1466 &hir::TyParamBound::TraitTyParamBound(ref poly_trait_ref, _) => {
1467 let mut projections = Vec::new();
1470 AstConv::instantiate_poly_trait_ref(&icx,
1475 predicates.push(trait_ref.to_predicate());
1477 for projection in &projections {
1478 predicates.push(projection.to_predicate());
1482 &hir::TyParamBound::RegionTyParamBound(ref lifetime) => {
1483 let region = AstConv::ast_region_to_region(&icx,
1486 let pred = ty::Binder::bind(ty::OutlivesPredicate(ty, region));
1487 predicates.push(ty::Predicate::TypeOutlives(pred))
1493 &hir::WherePredicate::RegionPredicate(ref region_pred) => {
1494 let r1 = AstConv::ast_region_to_region(&icx, ®ion_pred.lifetime, None);
1495 for bound in ®ion_pred.bounds {
1496 let r2 = AstConv::ast_region_to_region(&icx, bound, None);
1497 let pred = ty::Binder::bind(ty::OutlivesPredicate(r1, r2));
1498 predicates.push(ty::Predicate::RegionOutlives(pred))
1502 &hir::WherePredicate::EqPredicate(..) => {
1508 // Add predicates from associated type bounds.
1509 if let Some((self_trait_ref, trait_items)) = is_trait {
1510 predicates.extend(trait_items.iter().flat_map(|trait_item_ref| {
1511 let trait_item = tcx.hir.trait_item(trait_item_ref.id);
1512 let bounds = match trait_item.node {
1513 hir::TraitItemKind::Type(ref bounds, _) => bounds,
1515 return vec![].into_iter();
1519 let assoc_ty = tcx.mk_projection(
1520 tcx.hir.local_def_id(trait_item.id),
1521 self_trait_ref.substs,
1524 let bounds = compute_bounds(&ItemCtxt::new(tcx, def_id),
1527 SizedByDefault::Yes,
1530 bounds.predicates(tcx, assoc_ty).into_iter()
1534 // Subtle: before we store the predicates into the tcx, we
1535 // sort them so that predicates like `T: Foo<Item=U>` come
1536 // before uses of `U`. This avoids false ambiguity errors
1537 // in trait checking. See `setup_constraining_predicates`
1539 if let NodeItem(&Item { node: ItemImpl(..), .. }) = node {
1540 let self_ty = tcx.type_of(def_id);
1541 let trait_ref = tcx.impl_trait_ref(def_id);
1542 ctp::setup_constraining_predicates(tcx,
1545 &mut ctp::parameters_for_impl(self_ty, trait_ref));
1548 ty::GenericPredicates {
1549 parent: generics.parent,
1554 pub enum SizedByDefault { Yes, No, }
1556 /// Translate the AST's notion of ty param bounds (which are an enum consisting of a newtyped Ty or
1557 /// a region) to ty's notion of ty param bounds, which can either be user-defined traits, or the
1558 /// built-in trait (formerly known as kind): Send.
1559 pub fn compute_bounds<'gcx: 'tcx, 'tcx>(astconv: &AstConv<'gcx, 'tcx>,
1561 ast_bounds: &[hir::TyParamBound],
1562 sized_by_default: SizedByDefault,
1566 let mut region_bounds = vec![];
1567 let mut trait_bounds = vec![];
1568 for ast_bound in ast_bounds {
1570 hir::TraitTyParamBound(ref b, hir::TraitBoundModifier::None) => {
1571 trait_bounds.push(b);
1573 hir::TraitTyParamBound(_, hir::TraitBoundModifier::Maybe) => {}
1574 hir::RegionTyParamBound(ref l) => {
1575 region_bounds.push(l);
1580 let mut projection_bounds = vec![];
1582 let mut trait_bounds: Vec<_> = trait_bounds.iter().map(|&bound| {
1583 astconv.instantiate_poly_trait_ref(bound,
1585 &mut projection_bounds)
1588 let region_bounds = region_bounds.into_iter().map(|r| {
1589 astconv.ast_region_to_region(r, None)
1592 trait_bounds.sort_by(|a,b| a.def_id().cmp(&b.def_id()));
1594 let implicitly_sized = if let SizedByDefault::Yes = sized_by_default {
1595 !is_unsized(astconv, ast_bounds, span)
1608 /// Converts a specific TyParamBound from the AST into a set of
1609 /// predicates that apply to the self-type. A vector is returned
1610 /// because this can be anywhere from 0 predicates (`T:?Sized` adds no
1611 /// predicates) to 1 (`T:Foo`) to many (`T:Bar<X=i32>` adds `T:Bar`
1612 /// and `<T as Bar>::X == i32`).
1613 fn predicates_from_bound<'tcx>(astconv: &AstConv<'tcx, 'tcx>,
1615 bound: &hir::TyParamBound)
1616 -> Vec<ty::Predicate<'tcx>>
1619 hir::TraitTyParamBound(ref tr, hir::TraitBoundModifier::None) => {
1620 let mut projections = Vec::new();
1621 let pred = astconv.instantiate_poly_trait_ref(tr,
1624 projections.into_iter()
1625 .map(|p| p.to_predicate())
1626 .chain(Some(pred.to_predicate()))
1629 hir::RegionTyParamBound(ref lifetime) => {
1630 let region = astconv.ast_region_to_region(lifetime, None);
1631 let pred = ty::Binder::bind(ty::OutlivesPredicate(param_ty, region));
1632 vec![ty::Predicate::TypeOutlives(pred)]
1634 hir::TraitTyParamBound(_, hir::TraitBoundModifier::Maybe) => {
1640 fn compute_sig_of_foreign_fn_decl<'a, 'tcx>(
1641 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1645 -> ty::PolyFnSig<'tcx>
1647 let fty = AstConv::ty_of_fn(&ItemCtxt::new(tcx, def_id), hir::Unsafety::Unsafe, abi, decl);
1649 // feature gate SIMD types in FFI, since I (huonw) am not sure the
1650 // ABIs are handled at all correctly.
1651 if abi != abi::Abi::RustIntrinsic && abi != abi::Abi::PlatformIntrinsic
1652 && !tcx.features().simd_ffi {
1653 let check = |ast_ty: &hir::Ty, ty: Ty| {
1655 tcx.sess.struct_span_err(ast_ty.span,
1656 &format!("use of SIMD type `{}` in FFI is highly experimental and \
1657 may result in invalid code",
1658 tcx.hir.node_to_pretty_string(ast_ty.id)))
1659 .help("add #![feature(simd_ffi)] to the crate attributes to enable")
1663 for (input, ty) in decl.inputs.iter().zip(*fty.inputs().skip_binder()) {
1666 if let hir::Return(ref ty) = decl.output {
1667 check(&ty, *fty.output().skip_binder())
1674 fn is_foreign_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1677 match tcx.hir.get_if_local(def_id) {
1678 Some(hir_map::NodeForeignItem(..)) => true,
1680 _ => bug!("is_foreign_item applied to non-local def-id {:?}", def_id)
1684 fn from_target_feature(
1687 attr: &ast::Attribute,
1688 whitelist: &FxHashMap<String, Option<String>>,
1689 target_features: &mut Vec<Symbol>,
1691 let list = match attr.meta_item_list() {
1694 let msg = "#[target_feature] attribute must be of the form \
1695 #[target_feature(..)]";
1696 tcx.sess.span_err(attr.span, &msg);
1700 let rust_features = tcx.features();
1702 // Only `enable = ...` is accepted in the meta item list
1703 if !item.check_name("enable") {
1704 let msg = "#[target_feature(..)] only accepts sub-keys of `enable` \
1706 tcx.sess.span_err(item.span, &msg);
1710 // Must be of the form `enable = "..."` ( a string)
1711 let value = match item.value_str() {
1712 Some(value) => value,
1714 let msg = "#[target_feature] attribute must be of the form \
1715 #[target_feature(enable = \"..\")]";
1716 tcx.sess.span_err(item.span, &msg);
1721 // We allow comma separation to enable multiple features
1722 for feature in value.as_str().split(',') {
1724 // Only allow whitelisted features per platform
1725 let feature_gate = match whitelist.get(feature) {
1728 let msg = format!("the feature named `{}` is not valid for \
1729 this target", feature);
1730 let mut err = tcx.sess.struct_span_err(item.span, &msg);
1732 if feature.starts_with("+") {
1733 let valid = whitelist.contains_key(&feature[1..]);
1735 err.help("consider removing the leading `+` in the feature name");
1743 // Only allow features whose feature gates have been enabled
1744 let allowed = match feature_gate.as_ref().map(|s| &**s) {
1745 Some("arm_target_feature") => rust_features.arm_target_feature,
1746 Some("aarch64_target_feature") => rust_features.aarch64_target_feature,
1747 Some("hexagon_target_feature") => rust_features.hexagon_target_feature,
1748 Some("powerpc_target_feature") => rust_features.powerpc_target_feature,
1749 Some("mips_target_feature") => rust_features.mips_target_feature,
1750 Some("avx512_target_feature") => rust_features.avx512_target_feature,
1751 Some("mmx_target_feature") => rust_features.mmx_target_feature,
1752 Some("sse4a_target_feature") => rust_features.sse4a_target_feature,
1753 Some("tbm_target_feature") => rust_features.tbm_target_feature,
1754 Some(name) => bug!("unknown target feature gate {}", name),
1757 if !allowed && id.is_local() {
1758 feature_gate::emit_feature_err(
1759 &tcx.sess.parse_sess,
1760 feature_gate.as_ref().unwrap(),
1762 feature_gate::GateIssue::Language,
1763 &format!("the target feature `{}` is currently unstable",
1768 target_features.push(Symbol::intern(feature));
1773 fn linkage_by_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId, name: &str) -> Linkage {
1774 use rustc::mir::mono::Linkage::*;
1776 // Use the names from src/llvm/docs/LangRef.rst here. Most types are only
1777 // applicable to variable declarations and may not really make sense for
1778 // Rust code in the first place but whitelist them anyway and trust that
1779 // the user knows what s/he's doing. Who knows, unanticipated use cases
1780 // may pop up in the future.
1782 // ghost, dllimport, dllexport and linkonce_odr_autohide are not supported
1783 // and don't have to be, LLVM treats them as no-ops.
1785 "appending" => Appending,
1786 "available_externally" => AvailableExternally,
1788 "extern_weak" => ExternalWeak,
1789 "external" => External,
1790 "internal" => Internal,
1791 "linkonce" => LinkOnceAny,
1792 "linkonce_odr" => LinkOnceODR,
1793 "private" => Private,
1795 "weak_odr" => WeakODR,
1797 let span = tcx.hir.span_if_local(def_id);
1798 if let Some(span) = span {
1799 tcx.sess.span_fatal(span, "invalid linkage specified")
1801 tcx.sess.fatal(&format!("invalid linkage specified: {}", name))
1807 fn trans_fn_attrs<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, id: DefId) -> TransFnAttrs {
1808 let attrs = tcx.get_attrs(id);
1810 let mut trans_fn_attrs = TransFnAttrs::new();
1812 let whitelist = tcx.target_features_whitelist(LOCAL_CRATE);
1814 let mut inline_span = None;
1815 for attr in attrs.iter() {
1816 if attr.check_name("cold") {
1817 trans_fn_attrs.flags |= TransFnAttrFlags::COLD;
1818 } else if attr.check_name("allocator") {
1819 trans_fn_attrs.flags |= TransFnAttrFlags::ALLOCATOR;
1820 } else if attr.check_name("unwind") {
1821 trans_fn_attrs.flags |= TransFnAttrFlags::UNWIND;
1822 } else if attr.check_name("rustc_allocator_nounwind") {
1823 trans_fn_attrs.flags |= TransFnAttrFlags::RUSTC_ALLOCATOR_NOUNWIND;
1824 } else if attr.check_name("naked") {
1825 trans_fn_attrs.flags |= TransFnAttrFlags::NAKED;
1826 } else if attr.check_name("no_mangle") {
1827 trans_fn_attrs.flags |= TransFnAttrFlags::NO_MANGLE;
1828 } else if attr.check_name("rustc_std_internal_symbol") {
1829 trans_fn_attrs.flags |= TransFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL;
1830 } else if attr.check_name("no_debug") {
1831 trans_fn_attrs.flags |= TransFnAttrFlags::NO_DEBUG;
1832 } else if attr.check_name("inline") {
1833 trans_fn_attrs.inline = attrs.iter().fold(InlineAttr::None, |ia, attr| {
1834 if attr.path != "inline" {
1837 let meta = match attr.meta() {
1838 Some(meta) => meta.node,
1842 MetaItemKind::Word => {
1846 MetaItemKind::List(ref items) => {
1848 inline_span = Some(attr.span);
1849 if items.len() != 1 {
1850 span_err!(tcx.sess.diagnostic(), attr.span, E0534,
1851 "expected one argument");
1853 } else if list_contains_name(&items[..], "always") {
1855 } else if list_contains_name(&items[..], "never") {
1858 span_err!(tcx.sess.diagnostic(), items[0].span, E0535,
1859 "invalid argument");
1867 } else if attr.check_name("export_name") {
1868 if let s @ Some(_) = attr.value_str() {
1869 trans_fn_attrs.export_name = s;
1871 struct_span_err!(tcx.sess, attr.span, E0558,
1872 "export_name attribute has invalid format")
1873 .span_label(attr.span, "did you mean #[export_name=\"*\"]?")
1876 } else if attr.check_name("target_feature") {
1877 if tcx.fn_sig(id).unsafety() == Unsafety::Normal {
1878 let msg = "#[target_feature(..)] can only be applied to \
1880 tcx.sess.span_err(attr.span, msg);
1882 from_target_feature(tcx, id, attr, &whitelist, &mut trans_fn_attrs.target_features);
1883 } else if attr.check_name("linkage") {
1884 if let Some(val) = attr.value_str() {
1885 trans_fn_attrs.linkage = Some(linkage_by_name(tcx, id, &val.as_str()));
1890 // If a function uses #[target_feature] it can't be inlined into general
1891 // purpose functions as they wouldn't have the right target features
1892 // enabled. For that reason we also forbid #[inline(always)] as it can't be
1894 if trans_fn_attrs.target_features.len() > 0 {
1895 if trans_fn_attrs.inline == InlineAttr::Always {
1896 if let Some(span) = inline_span {
1897 tcx.sess.span_err(span, "cannot use #[inline(always)] with \
1898 #[target_feature]");