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::const_val::ConstVal;
32 use middle::resolve_lifetime as rl;
33 use rustc::traits::Reveal;
34 use rustc::ty::subst::Substs;
35 use rustc::ty::{ToPredicate, ReprOptions};
36 use rustc::ty::{self, AdtKind, ToPolyTraitRef, Ty, TyCtxt};
37 use rustc::ty::maps::Providers;
38 use rustc::ty::util::IntTypeExt;
39 use util::nodemap::FxHashMap;
41 use rustc_const_math::ConstInt;
43 use std::collections::BTreeMap;
45 use syntax::{abi, ast};
46 use syntax::codemap::Spanned;
47 use syntax::symbol::{Symbol, keywords};
48 use syntax_pos::{Span, DUMMY_SP};
50 use rustc::hir::{self, map as hir_map};
51 use rustc::hir::intravisit::{self, Visitor, NestedVisitorMap};
52 use rustc::hir::def::{Def, CtorKind};
53 use rustc::hir::def_id::DefId;
55 ///////////////////////////////////////////////////////////////////////////
58 pub fn collect_item_types<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
59 let mut visitor = CollectItemTypesVisitor { tcx: tcx };
60 tcx.hir.krate().visit_all_item_likes(&mut visitor.as_deep_visitor());
63 pub fn provide(providers: &mut Providers) {
64 *providers = Providers {
69 type_param_predicates,
81 ///////////////////////////////////////////////////////////////////////////
83 /// Context specific to some particular item. This is what implements
84 /// AstConv. It has information about the predicates that are defined
85 /// on the trait. Unfortunately, this predicate information is
86 /// available in various different forms at various points in the
87 /// process. So we can't just store a pointer to e.g. the AST or the
88 /// parsed ty form, we have to be more flexible. To this end, the
89 /// `ItemCtxt` is parameterized by a `DefId` that it uses to satisfy
90 /// `get_type_parameter_bounds` requests, drawing the information from
91 /// the AST (`hir::Generics`), recursively.
92 pub struct ItemCtxt<'a,'tcx:'a> {
93 tcx: TyCtxt<'a, 'tcx, 'tcx>,
97 ///////////////////////////////////////////////////////////////////////////
99 struct CollectItemTypesVisitor<'a, 'tcx: 'a> {
100 tcx: TyCtxt<'a, 'tcx, 'tcx>
103 impl<'a, 'tcx> Visitor<'tcx> for CollectItemTypesVisitor<'a, 'tcx> {
104 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
105 NestedVisitorMap::OnlyBodies(&self.tcx.hir)
108 fn visit_item(&mut self, item: &'tcx hir::Item) {
109 convert_item(self.tcx, item.id);
110 intravisit::walk_item(self, item);
113 fn visit_generics(&mut self, generics: &'tcx hir::Generics) {
114 for param in &generics.ty_params {
115 if param.default.is_some() {
116 let def_id = self.tcx.hir.local_def_id(param.id);
117 self.tcx.type_of(def_id);
120 intravisit::walk_generics(self, generics);
123 fn visit_expr(&mut self, expr: &'tcx hir::Expr) {
124 if let hir::ExprClosure(..) = expr.node {
125 let def_id = self.tcx.hir.local_def_id(expr.id);
126 self.tcx.generics_of(def_id);
127 self.tcx.type_of(def_id);
129 intravisit::walk_expr(self, expr);
132 fn visit_ty(&mut self, ty: &'tcx hir::Ty) {
133 if let hir::TyImplTrait(..) = ty.node {
134 let def_id = self.tcx.hir.local_def_id(ty.id);
135 self.tcx.generics_of(def_id);
136 self.tcx.predicates_of(def_id);
138 intravisit::walk_ty(self, ty);
141 fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem) {
142 convert_trait_item(self.tcx, trait_item.id);
143 intravisit::walk_trait_item(self, trait_item);
146 fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem) {
147 convert_impl_item(self.tcx, impl_item.id);
148 intravisit::walk_impl_item(self, impl_item);
152 ///////////////////////////////////////////////////////////////////////////
153 // Utility types and common code for the above passes.
155 impl<'a, 'tcx> ItemCtxt<'a, 'tcx> {
156 pub fn new(tcx: TyCtxt<'a, 'tcx, 'tcx>, item_def_id: DefId)
157 -> ItemCtxt<'a,'tcx> {
165 impl<'a,'tcx> ItemCtxt<'a,'tcx> {
166 pub fn to_ty(&self, ast_ty: &hir::Ty) -> Ty<'tcx> {
167 AstConv::ast_ty_to_ty(self, ast_ty)
171 impl<'a, 'tcx> AstConv<'tcx, 'tcx> for ItemCtxt<'a, 'tcx> {
172 fn tcx<'b>(&'b self) -> TyCtxt<'b, 'tcx, 'tcx> { self.tcx }
174 fn get_type_parameter_bounds(&self,
177 -> ty::GenericPredicates<'tcx>
179 self.tcx.at(span).type_param_predicates((self.item_def_id, def_id))
182 fn re_infer(&self, _span: Span, _def: Option<&ty::RegionParameterDef>)
183 -> Option<ty::Region<'tcx>> {
187 fn ty_infer(&self, span: Span) -> Ty<'tcx> {
192 "the type placeholder `_` is not allowed within types on item signatures"
193 ).span_label(span, "not allowed in type signatures")
198 fn projected_ty_from_poly_trait_ref(&self,
201 poly_trait_ref: ty::PolyTraitRef<'tcx>)
204 if let Some(trait_ref) = self.tcx().no_late_bound_regions(&poly_trait_ref) {
205 self.tcx().mk_projection(item_def_id, trait_ref.substs)
207 // no late-bound regions, we can just ignore the binder
208 span_err!(self.tcx().sess, span, E0212,
209 "cannot extract an associated type from a higher-ranked trait bound \
215 fn normalize_ty(&self, _span: Span, ty: Ty<'tcx>) -> Ty<'tcx> {
216 // types in item signatures are not normalized, to avoid undue
221 fn set_tainted_by_errors(&self) {
222 // no obvious place to track this, just let it go
225 fn record_ty(&self, _hir_id: hir::HirId, _ty: Ty<'tcx>, _span: Span) {
226 // no place to record types from signatures?
230 fn type_param_predicates<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
231 (item_def_id, def_id): (DefId, DefId))
232 -> ty::GenericPredicates<'tcx> {
233 use rustc::hir::map::*;
236 // In the AST, bounds can derive from two places. Either
237 // written inline like `<T:Foo>` or in a where clause like
240 let param_id = tcx.hir.as_local_node_id(def_id).unwrap();
241 let param_owner = tcx.hir.ty_param_owner(param_id);
242 let param_owner_def_id = tcx.hir.local_def_id(param_owner);
243 let generics = tcx.generics_of(param_owner_def_id);
244 let index = generics.type_param_to_index[&def_id.index];
245 let ty = tcx.mk_param(index, tcx.hir.ty_param_name(param_id));
247 // Don't look for bounds where the type parameter isn't in scope.
248 let parent = if item_def_id == param_owner_def_id {
251 tcx.generics_of(item_def_id).parent
254 let mut result = parent.map_or(ty::GenericPredicates {
258 let icx = ItemCtxt::new(tcx, parent);
259 icx.get_type_parameter_bounds(DUMMY_SP, def_id)
262 let item_node_id = tcx.hir.as_local_node_id(item_def_id).unwrap();
263 let ast_generics = match tcx.hir.get(item_node_id) {
264 NodeTraitItem(item) => {
266 TraitItemKind::Method(ref sig, _) => &sig.generics,
271 NodeImplItem(item) => {
273 ImplItemKind::Method(ref sig, _) => &sig.generics,
280 ItemFn(.., ref generics, _) |
281 ItemImpl(_, _, _, ref generics, ..) |
282 ItemTy(_, ref generics) |
283 ItemEnum(_, ref generics) |
284 ItemStruct(_, ref generics) |
285 ItemUnion(_, ref generics) => generics,
286 ItemTrait(_, ref generics, ..) => {
287 // Implied `Self: Trait` and supertrait bounds.
288 if param_id == item_node_id {
289 result.predicates.push(ty::TraitRef {
291 substs: Substs::identity_for_item(tcx, item_def_id)
300 NodeForeignItem(item) => {
302 ForeignItemFn(_, _, ref generics) => generics,
310 let icx = ItemCtxt::new(tcx, item_def_id);
311 result.predicates.extend(
312 icx.type_parameter_bounds_in_generics(ast_generics, param_id, ty));
316 impl<'a, 'tcx> ItemCtxt<'a, 'tcx> {
317 /// Find bounds from hir::Generics. This requires scanning through the
318 /// AST. We do this to avoid having to convert *all* the bounds, which
319 /// would create artificial cycles. Instead we can only convert the
320 /// bounds for a type parameter `X` if `X::Foo` is used.
321 fn type_parameter_bounds_in_generics(&self,
322 ast_generics: &hir::Generics,
323 param_id: ast::NodeId,
325 -> Vec<ty::Predicate<'tcx>>
328 ast_generics.ty_params
330 .filter(|p| p.id == param_id)
331 .flat_map(|p| p.bounds.iter())
332 .flat_map(|b| predicates_from_bound(self, ty, b));
334 let from_where_clauses =
335 ast_generics.where_clause
338 .filter_map(|wp| match *wp {
339 hir::WherePredicate::BoundPredicate(ref bp) => Some(bp),
342 .filter(|bp| is_param(self.tcx, &bp.bounded_ty, param_id))
343 .flat_map(|bp| bp.bounds.iter())
344 .flat_map(|b| predicates_from_bound(self, ty, b));
346 from_ty_params.chain(from_where_clauses).collect()
350 /// Tests whether this is the AST for a reference to the type
351 /// parameter with id `param_id`. We use this so as to avoid running
352 /// `ast_ty_to_ty`, because we want to avoid triggering an all-out
353 /// conversion of the type to avoid inducing unnecessary cycles.
354 fn is_param<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
356 param_id: ast::NodeId)
359 if let hir::TyPath(hir::QPath::Resolved(None, ref path)) = ast_ty.node {
361 Def::SelfTy(Some(def_id), None) |
362 Def::TyParam(def_id) => {
363 def_id == tcx.hir.local_def_id(param_id)
372 fn ensure_no_ty_param_bounds(tcx: TyCtxt,
374 generics: &hir::Generics,
375 thing: &'static str) {
376 let mut warn = false;
378 for ty_param in generics.ty_params.iter() {
379 for bound in ty_param.bounds.iter() {
381 hir::TraitTyParamBound(..) => {
384 hir::RegionTyParamBound(..) => { }
389 for predicate in generics.where_clause.predicates.iter() {
391 hir::WherePredicate::BoundPredicate(..) => {
394 hir::WherePredicate::RegionPredicate(..) => { }
395 hir::WherePredicate::EqPredicate(..) => { }
400 // According to accepted RFC #XXX, we should
401 // eventually accept these, but it will not be
402 // part of this PR. Still, convert to warning to
403 // make bootstrapping easier.
404 span_warn!(tcx.sess, span, E0122,
405 "trait bounds are not (yet) enforced \
411 fn convert_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, item_id: ast::NodeId) {
412 let it = tcx.hir.expect_item(item_id);
413 debug!("convert: item {} with id {}", it.name, it.id);
414 let def_id = tcx.hir.local_def_id(item_id);
416 // These don't define types.
417 hir::ItemExternCrate(_) |
420 hir::ItemGlobalAsm(_) => {}
421 hir::ItemForeignMod(ref foreign_mod) => {
422 for item in &foreign_mod.items {
423 let def_id = tcx.hir.local_def_id(item.id);
424 tcx.generics_of(def_id);
426 tcx.predicates_of(def_id);
427 if let hir::ForeignItemFn(..) = item.node {
432 hir::ItemEnum(ref enum_definition, _) => {
433 tcx.generics_of(def_id);
435 tcx.predicates_of(def_id);
436 convert_enum_variant_types(tcx, def_id, &enum_definition.variants);
438 hir::ItemDefaultImpl(..) => {
439 tcx.impl_trait_ref(def_id);
441 hir::ItemImpl(..) => {
442 tcx.generics_of(def_id);
444 tcx.impl_trait_ref(def_id);
445 tcx.predicates_of(def_id);
447 hir::ItemTrait(..) => {
448 tcx.generics_of(def_id);
449 tcx.trait_def(def_id);
450 tcx.at(it.span).super_predicates_of(def_id);
451 tcx.predicates_of(def_id);
453 hir::ItemStruct(ref struct_def, _) |
454 hir::ItemUnion(ref struct_def, _) => {
455 tcx.generics_of(def_id);
457 tcx.predicates_of(def_id);
459 for f in struct_def.fields() {
460 let def_id = tcx.hir.local_def_id(f.id);
461 tcx.generics_of(def_id);
463 tcx.predicates_of(def_id);
466 if !struct_def.is_struct() {
467 convert_variant_ctor(tcx, struct_def.id());
470 hir::ItemTy(_, ref generics) => {
471 ensure_no_ty_param_bounds(tcx, it.span, generics, "type");
472 tcx.generics_of(def_id);
474 tcx.predicates_of(def_id);
476 hir::ItemStatic(..) | hir::ItemConst(..) | hir::ItemFn(..) => {
477 tcx.generics_of(def_id);
479 tcx.predicates_of(def_id);
480 if let hir::ItemFn(..) = it.node {
487 fn convert_trait_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, trait_item_id: ast::NodeId) {
488 let trait_item = tcx.hir.expect_trait_item(trait_item_id);
489 let def_id = tcx.hir.local_def_id(trait_item.id);
490 tcx.generics_of(def_id);
492 match trait_item.node {
493 hir::TraitItemKind::Const(..) |
494 hir::TraitItemKind::Type(_, Some(_)) |
495 hir::TraitItemKind::Method(..) => {
497 if let hir::TraitItemKind::Method(..) = trait_item.node {
502 hir::TraitItemKind::Type(_, None) => {}
505 tcx.predicates_of(def_id);
508 fn convert_impl_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, impl_item_id: ast::NodeId) {
509 let def_id = tcx.hir.local_def_id(impl_item_id);
510 tcx.generics_of(def_id);
512 tcx.predicates_of(def_id);
513 if let hir::ImplItemKind::Method(..) = tcx.hir.expect_impl_item(impl_item_id).node {
518 fn convert_variant_ctor<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
519 ctor_id: ast::NodeId) {
520 let def_id = tcx.hir.local_def_id(ctor_id);
521 tcx.generics_of(def_id);
523 tcx.predicates_of(def_id);
526 fn convert_enum_variant_types<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
528 variants: &[hir::Variant]) {
529 let param_env = ty::ParamEnv::empty(Reveal::UserFacing);
530 let def = tcx.adt_def(def_id);
531 let repr_type = def.repr.discr_type();
532 let initial = repr_type.initial_discriminant(tcx);
533 let mut prev_discr = None::<ConstInt>;
535 // fill the discriminant values and field types
536 for variant in variants {
537 let wrapped_discr = prev_discr.map_or(initial, |d| d.wrap_incr());
538 prev_discr = Some(if let Some(e) = variant.node.disr_expr {
539 let expr_did = tcx.hir.local_def_id(e.node_id);
540 let substs = Substs::identity_for_item(tcx, expr_did);
541 let result = tcx.at(variant.span).const_eval(param_env.and((expr_did, substs)));
543 // enum variant evaluation happens before the global constant check
544 // so we need to report the real error
545 if let Err(ref err) = result {
546 err.report(tcx, variant.span, "enum discriminant");
550 Ok(&ty::Const { val: ConstVal::Integral(x), .. }) => Some(x),
553 } else if let Some(discr) = repr_type.disr_incr(tcx, prev_discr) {
556 struct_span_err!(tcx.sess, variant.span, E0370,
557 "enum discriminant overflowed")
558 .span_label(variant.span, format!("overflowed on value after {}",
559 prev_discr.unwrap()))
560 .note(&format!("explicitly set `{} = {}` if that is desired outcome",
561 variant.node.name, wrapped_discr))
564 }.unwrap_or(wrapped_discr));
566 for f in variant.node.data.fields() {
567 let def_id = tcx.hir.local_def_id(f.id);
568 tcx.generics_of(def_id);
570 tcx.predicates_of(def_id);
573 // Convert the ctor, if any. This also registers the variant as
575 convert_variant_ctor(tcx, variant.node.data.id());
579 fn convert_struct_variant<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
582 discr: ty::VariantDiscr,
583 def: &hir::VariantData)
585 let mut seen_fields: FxHashMap<ast::Name, Span> = FxHashMap();
586 let node_id = tcx.hir.as_local_node_id(did).unwrap();
587 let fields = def.fields().iter().map(|f| {
588 let fid = tcx.hir.local_def_id(f.id);
589 let dup_span = seen_fields.get(&f.name).cloned();
590 if let Some(prev_span) = dup_span {
591 struct_span_err!(tcx.sess, f.span, E0124,
592 "field `{}` is already declared",
594 .span_label(f.span, "field already declared")
595 .span_label(prev_span, format!("`{}` first declared here", f.name))
598 seen_fields.insert(f.name, f.span);
604 vis: ty::Visibility::from_hir(&f.vis, node_id, tcx)
612 ctor_kind: CtorKind::from_hir(def),
616 fn adt_def<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
618 -> &'tcx ty::AdtDef {
619 use rustc::hir::map::*;
622 let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
623 let item = match tcx.hir.get(node_id) {
624 NodeItem(item) => item,
628 let repr = ReprOptions::new(tcx, def_id);
629 let (kind, variants) = match item.node {
630 ItemEnum(ref def, _) => {
631 let mut distance_from_explicit = 0;
632 (AdtKind::Enum, def.variants.iter().map(|v| {
633 let did = tcx.hir.local_def_id(v.node.data.id());
634 let discr = if let Some(e) = v.node.disr_expr {
635 distance_from_explicit = 0;
636 ty::VariantDiscr::Explicit(tcx.hir.local_def_id(e.node_id))
638 ty::VariantDiscr::Relative(distance_from_explicit)
640 distance_from_explicit += 1;
642 convert_struct_variant(tcx, did, v.node.name, discr, &v.node.data)
645 ItemStruct(ref def, _) => {
646 // Use separate constructor id for unit/tuple structs and reuse did for braced structs.
647 let ctor_id = if !def.is_struct() {
648 Some(tcx.hir.local_def_id(def.id()))
652 (AdtKind::Struct, vec![
653 convert_struct_variant(tcx, ctor_id.unwrap_or(def_id), item.name,
654 ty::VariantDiscr::Relative(0), def)
657 ItemUnion(ref def, _) => {
658 (AdtKind::Union, vec![
659 convert_struct_variant(tcx, def_id, item.name,
660 ty::VariantDiscr::Relative(0), def)
665 tcx.alloc_adt_def(def_id, kind, variants, repr)
668 /// Ensures that the super-predicates of the trait with def-id
669 /// trait_def_id are converted and stored. This also ensures that
670 /// the transitive super-predicates are converted;
671 fn super_predicates_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
673 -> ty::GenericPredicates<'tcx> {
674 debug!("super_predicates(trait_def_id={:?})", trait_def_id);
675 let trait_node_id = tcx.hir.as_local_node_id(trait_def_id).unwrap();
677 let item = match tcx.hir.get(trait_node_id) {
678 hir_map::NodeItem(item) => item,
679 _ => bug!("trait_node_id {} is not an item", trait_node_id)
682 let (generics, bounds) = match item.node {
683 hir::ItemTrait(_, ref generics, ref supertraits, _) => (generics, supertraits),
684 _ => span_bug!(item.span,
685 "super_predicates invoked on non-trait"),
688 let icx = ItemCtxt::new(tcx, trait_def_id);
690 // Convert the bounds that follow the colon, e.g. `Bar+Zed` in `trait Foo : Bar+Zed`.
691 let self_param_ty = tcx.mk_self_type();
692 let superbounds1 = compute_bounds(&icx,
698 let superbounds1 = superbounds1.predicates(tcx, self_param_ty);
700 // Convert any explicit superbounds in the where clause,
701 // e.g. `trait Foo where Self : Bar`:
702 let superbounds2 = icx.type_parameter_bounds_in_generics(generics, item.id, self_param_ty);
704 // Combine the two lists to form the complete set of superbounds:
705 let superbounds: Vec<_> = superbounds1.into_iter().chain(superbounds2).collect();
707 // Now require that immediate supertraits are converted,
708 // which will, in turn, reach indirect supertraits.
709 for bound in superbounds.iter().filter_map(|p| p.to_opt_poly_trait_ref()) {
710 tcx.at(item.span).super_predicates_of(bound.def_id());
713 ty::GenericPredicates {
715 predicates: superbounds
719 fn trait_def<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
721 -> &'tcx ty::TraitDef {
722 let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
723 let item = tcx.hir.expect_item(node_id);
725 let unsafety = match item.node {
726 hir::ItemTrait(unsafety, ..) => unsafety,
727 _ => span_bug!(item.span, "trait_def_of_item invoked on non-trait"),
730 let paren_sugar = tcx.has_attr(def_id, "rustc_paren_sugar");
731 if paren_sugar && !tcx.sess.features.borrow().unboxed_closures {
732 let mut err = tcx.sess.struct_span_err(
734 "the `#[rustc_paren_sugar]` attribute is a temporary means of controlling \
735 which traits can use parenthetical notation");
737 "add `#![feature(unboxed_closures)]` to \
738 the crate attributes to use it");
742 let def_path_hash = tcx.def_path_hash(def_id);
743 let has_default_impl = tcx.hir.trait_is_auto(def_id);
744 let def = ty::TraitDef::new(def_id,
749 tcx.alloc_trait_def(def)
752 fn has_late_bound_regions<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
753 node: hir_map::Node<'tcx>)
755 struct LateBoundRegionsDetector<'a, 'tcx: 'a> {
756 tcx: TyCtxt<'a, 'tcx, 'tcx>,
758 has_late_bound_regions: Option<Span>,
761 impl<'a, 'tcx> Visitor<'tcx> for LateBoundRegionsDetector<'a, 'tcx> {
762 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
763 NestedVisitorMap::None
766 fn visit_ty(&mut self, ty: &'tcx hir::Ty) {
767 if self.has_late_bound_regions.is_some() { return }
769 hir::TyBareFn(..) => {
770 self.binder_depth += 1;
771 intravisit::walk_ty(self, ty);
772 self.binder_depth -= 1;
774 _ => intravisit::walk_ty(self, ty)
778 fn visit_poly_trait_ref(&mut self,
779 tr: &'tcx hir::PolyTraitRef,
780 m: hir::TraitBoundModifier) {
781 if self.has_late_bound_regions.is_some() { return }
782 self.binder_depth += 1;
783 intravisit::walk_poly_trait_ref(self, tr, m);
784 self.binder_depth -= 1;
787 fn visit_lifetime(&mut self, lt: &'tcx hir::Lifetime) {
788 if self.has_late_bound_regions.is_some() { return }
790 let hir_id = self.tcx.hir.node_to_hir_id(lt.id);
791 match self.tcx.named_region(hir_id) {
792 Some(rl::Region::Static) | Some(rl::Region::EarlyBound(..)) => {}
793 Some(rl::Region::LateBound(debruijn, _)) |
794 Some(rl::Region::LateBoundAnon(debruijn, _))
795 if debruijn.depth < self.binder_depth => {}
796 _ => self.has_late_bound_regions = Some(lt.span),
801 fn has_late_bound_regions<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
802 generics: &'tcx hir::Generics,
803 decl: &'tcx hir::FnDecl)
805 let mut visitor = LateBoundRegionsDetector {
806 tcx, binder_depth: 1, has_late_bound_regions: None
808 for lifetime in &generics.lifetimes {
809 let hir_id = tcx.hir.node_to_hir_id(lifetime.lifetime.id);
810 if tcx.is_late_bound(hir_id) {
811 return Some(lifetime.lifetime.span);
814 visitor.visit_fn_decl(decl);
815 visitor.has_late_bound_regions
819 hir_map::NodeTraitItem(item) => match item.node {
820 hir::TraitItemKind::Method(ref sig, _) =>
821 has_late_bound_regions(tcx, &sig.generics, &sig.decl),
824 hir_map::NodeImplItem(item) => match item.node {
825 hir::ImplItemKind::Method(ref sig, _) =>
826 has_late_bound_regions(tcx, &sig.generics, &sig.decl),
829 hir_map::NodeForeignItem(item) => match item.node {
830 hir::ForeignItemFn(ref fn_decl, _, ref generics) =>
831 has_late_bound_regions(tcx, generics, fn_decl),
834 hir_map::NodeItem(item) => match item.node {
835 hir::ItemFn(ref fn_decl, .., ref generics, _) =>
836 has_late_bound_regions(tcx, generics, fn_decl),
843 fn generics_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
845 -> &'tcx ty::Generics {
846 use rustc::hir::map::*;
849 let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
851 let node = tcx.hir.get(node_id);
852 let parent_def_id = match node {
858 let parent_id = tcx.hir.get_parent(node_id);
859 Some(tcx.hir.local_def_id(parent_id))
861 NodeExpr(&hir::Expr { node: hir::ExprClosure(..), .. }) => {
862 Some(tcx.closure_base_def_id(def_id))
864 NodeTy(&hir::Ty { node: hir::TyImplTrait(..), .. }) => {
865 let mut parent_id = node_id;
867 match tcx.hir.get(parent_id) {
868 NodeItem(_) | NodeImplItem(_) | NodeTraitItem(_) => break,
870 parent_id = tcx.hir.get_parent_node(parent_id);
874 Some(tcx.hir.local_def_id(parent_id))
879 let mut opt_self = None;
880 let mut allow_defaults = false;
882 let no_generics = hir::Generics::empty();
883 let ast_generics = match node {
884 NodeTraitItem(item) => {
886 TraitItemKind::Method(ref sig, _) => &sig.generics,
891 NodeImplItem(item) => {
893 ImplItemKind::Method(ref sig, _) => &sig.generics,
900 ItemFn(.., ref generics, _) |
901 ItemImpl(_, _, _, ref generics, ..) => generics,
903 ItemTy(_, ref generics) |
904 ItemEnum(_, ref generics) |
905 ItemStruct(_, ref generics) |
906 ItemUnion(_, ref generics) => {
907 allow_defaults = true;
911 ItemTrait(_, ref generics, ..) => {
912 // Add in the self type parameter.
914 // Something of a hack: use the node id for the trait, also as
915 // the node id for the Self type parameter.
916 let param_id = item.id;
918 opt_self = Some(ty::TypeParameterDef {
920 name: keywords::SelfType.name(),
921 def_id: tcx.hir.local_def_id(param_id),
923 object_lifetime_default: rl::Set1::Empty,
924 pure_wrt_drop: false,
928 allow_defaults = true;
936 NodeForeignItem(item) => {
938 ForeignItemStatic(..) => &no_generics,
939 ForeignItemFn(_, _, ref generics) => generics
946 let has_self = opt_self.is_some();
947 let mut parent_has_self = false;
948 let mut own_start = has_self as u32;
949 let (parent_regions, parent_types) = parent_def_id.map_or((0, 0), |def_id| {
950 let generics = tcx.generics_of(def_id);
951 assert_eq!(has_self, false);
952 parent_has_self = generics.has_self;
953 own_start = generics.count() as u32;
954 (generics.parent_regions + generics.regions.len() as u32,
955 generics.parent_types + generics.types.len() as u32)
958 let early_lifetimes = early_bound_lifetimes_from_generics(tcx, ast_generics);
959 let regions = early_lifetimes.enumerate().map(|(i, l)| {
960 ty::RegionParameterDef {
961 name: l.lifetime.name.name(),
962 index: own_start + i as u32,
963 def_id: tcx.hir.local_def_id(l.lifetime.id),
964 pure_wrt_drop: l.pure_wrt_drop,
966 }).collect::<Vec<_>>();
968 let hir_id = tcx.hir.node_to_hir_id(node_id);
969 let object_lifetime_defaults = tcx.object_lifetime_defaults(hir_id);
971 // Now create the real type parameters.
972 let type_start = own_start + regions.len() as u32;
973 let types = ast_generics.ty_params.iter().enumerate().map(|(i, p)| {
974 if p.name == keywords::SelfType.name() {
975 span_bug!(p.span, "`Self` should not be the name of a regular parameter");
978 if !allow_defaults && p.default.is_some() {
979 if !tcx.sess.features.borrow().default_type_parameter_fallback {
981 lint::builtin::INVALID_TYPE_PARAM_DEFAULT,
984 &format!("defaults for type parameters are only allowed in `struct`, \
985 `enum`, `type`, or `trait` definitions."));
989 ty::TypeParameterDef {
990 index: type_start + i as u32,
992 def_id: tcx.hir.local_def_id(p.id),
993 has_default: p.default.is_some(),
994 object_lifetime_default:
995 object_lifetime_defaults.as_ref().map_or(rl::Set1::Empty, |o| o[i]),
996 pure_wrt_drop: p.pure_wrt_drop,
997 synthetic: p.synthetic,
1000 let mut types: Vec<_> = opt_self.into_iter().chain(types).collect();
1002 // provide junk type parameter defs - the only place that
1003 // cares about anything but the length is instantiation,
1004 // and we don't do that for closures.
1005 if let NodeExpr(&hir::Expr { node: hir::ExprClosure(..), .. }) = node {
1006 tcx.with_freevars(node_id, |fv| {
1007 types.extend(fv.iter().enumerate().map(|(i, _)| ty::TypeParameterDef {
1008 index: type_start + i as u32,
1009 name: Symbol::intern("<upvar>"),
1012 object_lifetime_default: rl::Set1::Empty,
1013 pure_wrt_drop: false,
1019 let mut type_param_to_index = BTreeMap::new();
1020 for param in &types {
1021 type_param_to_index.insert(param.def_id.index, param.index);
1024 tcx.alloc_generics(ty::Generics {
1025 parent: parent_def_id,
1030 type_param_to_index,
1031 has_self: has_self || parent_has_self,
1032 has_late_bound_regions: has_late_bound_regions(tcx, node),
1036 fn type_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1039 use rustc::hir::map::*;
1042 let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
1044 let icx = ItemCtxt::new(tcx, def_id);
1046 match tcx.hir.get(node_id) {
1047 NodeTraitItem(item) => {
1049 TraitItemKind::Method(..) => {
1050 let substs = Substs::identity_for_item(tcx, def_id);
1051 tcx.mk_fn_def(def_id, substs)
1053 TraitItemKind::Const(ref ty, _) |
1054 TraitItemKind::Type(_, Some(ref ty)) => icx.to_ty(ty),
1055 TraitItemKind::Type(_, None) => {
1056 span_bug!(item.span, "associated type missing default");
1061 NodeImplItem(item) => {
1063 ImplItemKind::Method(..) => {
1064 let substs = Substs::identity_for_item(tcx, def_id);
1065 tcx.mk_fn_def(def_id, substs)
1067 ImplItemKind::Const(ref ty, _) => icx.to_ty(ty),
1068 ImplItemKind::Type(ref ty) => {
1069 if tcx.impl_trait_ref(tcx.hir.get_parent_did(node_id)).is_none() {
1070 span_err!(tcx.sess, item.span, E0202,
1071 "associated types are not allowed in inherent impls");
1081 ItemStatic(ref t, ..) | ItemConst(ref t, _) |
1082 ItemTy(ref t, _) | ItemImpl(.., ref t, _) => {
1086 let substs = Substs::identity_for_item(tcx, def_id);
1087 tcx.mk_fn_def(def_id, substs)
1092 let def = tcx.adt_def(def_id);
1093 let substs = Substs::identity_for_item(tcx, def_id);
1094 tcx.mk_adt(def, substs)
1096 ItemDefaultImpl(..) |
1099 ItemForeignMod(..) |
1101 ItemExternCrate(..) |
1105 "compute_type_of_item: unexpected item type: {:?}",
1111 NodeForeignItem(foreign_item) => {
1112 match foreign_item.node {
1113 ForeignItemFn(..) => {
1114 let substs = Substs::identity_for_item(tcx, def_id);
1115 tcx.mk_fn_def(def_id, substs)
1117 ForeignItemStatic(ref t, _) => icx.to_ty(t)
1121 NodeStructCtor(&ref def) |
1122 NodeVariant(&Spanned { node: hir::Variant_ { data: ref def, .. }, .. }) => {
1124 VariantData::Unit(..) | VariantData::Struct(..) => {
1125 tcx.type_of(tcx.hir.get_parent_did(node_id))
1127 VariantData::Tuple(..) => {
1128 let substs = Substs::identity_for_item(tcx, def_id);
1129 tcx.mk_fn_def(def_id, substs)
1134 NodeField(field) => icx.to_ty(&field.ty),
1136 NodeExpr(&hir::Expr { node: hir::ExprClosure(.., is_generator), .. }) => {
1138 let hir_id = tcx.hir.node_to_hir_id(node_id);
1139 return tcx.typeck_tables_of(def_id).node_id_to_type(hir_id);
1142 tcx.mk_closure(def_id, Substs::for_item(
1145 let region = def.to_early_bound_region_data();
1146 tcx.mk_region(ty::ReEarlyBound(region))
1148 |def, _| tcx.mk_param_from_def(def)
1152 NodeExpr(_) => match tcx.hir.get(tcx.hir.get_parent_node(node_id)) {
1153 NodeTy(&hir::Ty { node: TyArray(_, body), .. }) |
1154 NodeTy(&hir::Ty { node: TyTypeof(body), .. }) |
1155 NodeExpr(&hir::Expr { node: ExprRepeat(_, body), .. })
1156 if body.node_id == node_id => tcx.types.usize,
1158 NodeVariant(&Spanned { node: Variant_ { disr_expr: Some(e), .. }, .. })
1159 if e.node_id == node_id => {
1160 tcx.adt_def(tcx.hir.get_parent_did(node_id))
1161 .repr.discr_type().to_ty(tcx)
1165 bug!("unexpected expr parent in type_of_def_id(): {:?}", x);
1169 NodeTyParam(&hir::TyParam { default: Some(ref ty), .. }) => {
1173 NodeTy(&hir::Ty { node: TyImplTrait(..), .. }) => {
1174 let owner = tcx.hir.get_parent_did(node_id);
1175 let hir_id = tcx.hir.node_to_hir_id(node_id);
1176 tcx.typeck_tables_of(owner).node_id_to_type(hir_id)
1180 bug!("unexpected sort of node in type_of_def_id(): {:?}", x);
1185 fn fn_sig<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1187 -> ty::PolyFnSig<'tcx> {
1188 use rustc::hir::map::*;
1191 let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
1193 let icx = ItemCtxt::new(tcx, def_id);
1195 match tcx.hir.get(node_id) {
1196 NodeTraitItem(&hir::TraitItem { node: TraitItemKind::Method(ref sig, _), .. }) |
1197 NodeImplItem(&hir::ImplItem { node: ImplItemKind::Method(ref sig, _), .. }) => {
1198 AstConv::ty_of_fn(&icx, sig.unsafety, sig.abi, &sig.decl)
1201 NodeItem(&hir::Item { node: ItemFn(ref decl, unsafety, _, abi, _, _), .. }) => {
1202 AstConv::ty_of_fn(&icx, unsafety, abi, decl)
1205 NodeForeignItem(&hir::ForeignItem { node: ForeignItemFn(ref fn_decl, _, _), .. }) => {
1206 let abi = tcx.hir.get_foreign_abi(node_id);
1207 compute_sig_of_foreign_fn_decl(tcx, def_id, fn_decl, abi)
1210 NodeStructCtor(&VariantData::Tuple(ref fields, _)) |
1211 NodeVariant(&Spanned { node: hir::Variant_ {
1212 data: VariantData::Tuple(ref fields, _), ..
1214 let ty = tcx.type_of(tcx.hir.get_parent_did(node_id));
1215 let inputs = fields.iter().map(|f| {
1216 tcx.type_of(tcx.hir.local_def_id(f.id))
1218 ty::Binder(tcx.mk_fn_sig(
1222 hir::Unsafety::Normal,
1227 NodeExpr(&hir::Expr { node: hir::ExprClosure(..), hir_id, .. }) => {
1228 tcx.typeck_tables_of(def_id).closure_tys()[hir_id]
1232 bug!("unexpected sort of node in fn_sig(): {:?}", x);
1237 fn impl_trait_ref<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1239 -> Option<ty::TraitRef<'tcx>> {
1240 let icx = ItemCtxt::new(tcx, def_id);
1242 let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
1243 match tcx.hir.expect_item(node_id).node {
1244 hir::ItemDefaultImpl(_, ref ast_trait_ref) => {
1245 Some(AstConv::instantiate_mono_trait_ref(&icx,
1247 tcx.mk_self_type()))
1249 hir::ItemImpl(.., ref opt_trait_ref, _, _) => {
1250 opt_trait_ref.as_ref().map(|ast_trait_ref| {
1251 let selfty = tcx.type_of(def_id);
1252 AstConv::instantiate_mono_trait_ref(&icx, ast_trait_ref, selfty)
1259 fn impl_polarity<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1261 -> hir::ImplPolarity {
1262 let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
1263 match tcx.hir.expect_item(node_id).node {
1264 hir::ItemImpl(_, polarity, ..) => polarity,
1265 ref item => bug!("impl_polarity: {:?} not an impl", item)
1269 // Is it marked with ?Sized
1270 fn is_unsized<'gcx: 'tcx, 'tcx>(astconv: &AstConv<'gcx, 'tcx>,
1271 ast_bounds: &[hir::TyParamBound],
1274 let tcx = astconv.tcx();
1276 // Try to find an unbound in bounds.
1277 let mut unbound = None;
1278 for ab in ast_bounds {
1279 if let &hir::TraitTyParamBound(ref ptr, hir::TraitBoundModifier::Maybe) = ab {
1280 if unbound.is_none() {
1281 unbound = Some(ptr.trait_ref.clone());
1283 span_err!(tcx.sess, span, E0203,
1284 "type parameter has more than one relaxed default \
1285 bound, only one is supported");
1290 let kind_id = tcx.lang_items().require(SizedTraitLangItem);
1293 // FIXME(#8559) currently requires the unbound to be built-in.
1294 if let Ok(kind_id) = kind_id {
1295 if tpb.path.def != Def::Trait(kind_id) {
1296 tcx.sess.span_warn(span,
1297 "default bound relaxed for a type parameter, but \
1298 this does nothing because the given bound is not \
1299 a default. Only `?Sized` is supported");
1303 _ if kind_id.is_ok() => {
1306 // No lang item for Sized, so we can't add it as a bound.
1313 /// Returns the early-bound lifetimes declared in this generics
1314 /// listing. For anything other than fns/methods, this is just all
1315 /// the lifetimes that are declared. For fns or methods, we have to
1316 /// screen out those that do not appear in any where-clauses etc using
1317 /// `resolve_lifetime::early_bound_lifetimes`.
1318 fn early_bound_lifetimes_from_generics<'a, 'tcx>(
1319 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1320 ast_generics: &'a hir::Generics)
1321 -> impl Iterator<Item=&'a hir::LifetimeDef>
1327 let hir_id = tcx.hir.node_to_hir_id(l.lifetime.id);
1328 !tcx.is_late_bound(hir_id)
1332 fn predicates_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1334 -> ty::GenericPredicates<'tcx> {
1335 explicit_predicates_of(tcx, def_id)
1338 fn explicit_predicates_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1340 -> ty::GenericPredicates<'tcx> {
1341 use rustc::hir::map::*;
1344 let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
1345 let node = tcx.hir.get(node_id);
1347 let mut is_trait = None;
1349 let icx = ItemCtxt::new(tcx, def_id);
1350 let no_generics = hir::Generics::empty();
1351 let ast_generics = match node {
1352 NodeTraitItem(item) => {
1354 TraitItemKind::Method(ref sig, _) => &sig.generics,
1359 NodeImplItem(item) => {
1361 ImplItemKind::Method(ref sig, _) => &sig.generics,
1368 ItemFn(.., ref generics, _) |
1369 ItemImpl(_, _, _, ref generics, ..) |
1370 ItemTy(_, ref generics) |
1371 ItemEnum(_, ref generics) |
1372 ItemStruct(_, ref generics) |
1373 ItemUnion(_, ref generics) => {
1377 ItemTrait(_, ref generics, .., ref items) => {
1378 is_trait = Some((ty::TraitRef {
1380 substs: Substs::identity_for_item(tcx, def_id)
1389 NodeForeignItem(item) => {
1391 ForeignItemStatic(..) => &no_generics,
1392 ForeignItemFn(_, _, ref generics) => generics
1396 NodeTy(&Ty { node: TyImplTrait(ref bounds), span, .. }) => {
1397 let substs = Substs::identity_for_item(tcx, def_id);
1398 let anon_ty = tcx.mk_anon(def_id, substs);
1400 // Collect the bounds, i.e. the `A+B+'c` in `impl A+B+'c`.
1401 let bounds = compute_bounds(&icx, anon_ty, bounds,
1402 SizedByDefault::Yes,
1404 return ty::GenericPredicates {
1406 predicates: bounds.predicates(tcx, anon_ty)
1413 let generics = tcx.generics_of(def_id);
1414 let parent_count = generics.parent_count() as u32;
1415 let has_own_self = generics.has_self && parent_count == 0;
1417 let mut predicates = vec![];
1419 // Below we'll consider the bounds on the type parameters (including `Self`)
1420 // and the explicit where-clauses, but to get the full set of predicates
1421 // on a trait we need to add in the supertrait bounds and bounds found on
1422 // associated types.
1423 if let Some((trait_ref, _)) = is_trait {
1424 predicates = tcx.super_predicates_of(def_id).predicates;
1426 // Add in a predicate that `Self:Trait` (where `Trait` is the
1427 // current trait). This is needed for builtin bounds.
1428 predicates.push(trait_ref.to_poly_trait_ref().to_predicate());
1431 // Collect the region predicates that were declared inline as
1432 // well. In the case of parameters declared on a fn or method, we
1433 // have to be careful to only iterate over early-bound regions.
1434 let mut index = parent_count + has_own_self as u32;
1435 for param in early_bound_lifetimes_from_generics(tcx, ast_generics) {
1436 let region = tcx.mk_region(ty::ReEarlyBound(ty::EarlyBoundRegion {
1437 def_id: tcx.hir.local_def_id(param.lifetime.id),
1439 name: param.lifetime.name.name(),
1443 for bound in ¶m.bounds {
1444 let bound_region = AstConv::ast_region_to_region(&icx, bound, None);
1445 let outlives = ty::Binder(ty::OutlivesPredicate(region, bound_region));
1446 predicates.push(outlives.to_predicate());
1450 // Collect the predicates that were written inline by the user on each
1451 // type parameter (e.g., `<T:Foo>`).
1452 for param in &ast_generics.ty_params {
1453 let param_ty = ty::ParamTy::new(index, param.name).to_ty(tcx);
1456 let bounds = compute_bounds(&icx,
1459 SizedByDefault::Yes,
1461 predicates.extend(bounds.predicates(tcx, param_ty));
1464 // Add in the bounds that appear in the where-clause
1465 let where_clause = &ast_generics.where_clause;
1466 for predicate in &where_clause.predicates {
1468 &hir::WherePredicate::BoundPredicate(ref bound_pred) => {
1469 let ty = icx.to_ty(&bound_pred.bounded_ty);
1471 for bound in bound_pred.bounds.iter() {
1473 &hir::TyParamBound::TraitTyParamBound(ref poly_trait_ref, _) => {
1474 let mut projections = Vec::new();
1477 AstConv::instantiate_poly_trait_ref(&icx,
1482 predicates.push(trait_ref.to_predicate());
1484 for projection in &projections {
1485 predicates.push(projection.to_predicate());
1489 &hir::TyParamBound::RegionTyParamBound(ref lifetime) => {
1490 let region = AstConv::ast_region_to_region(&icx,
1493 let pred = ty::Binder(ty::OutlivesPredicate(ty, region));
1494 predicates.push(ty::Predicate::TypeOutlives(pred))
1500 &hir::WherePredicate::RegionPredicate(ref region_pred) => {
1501 let r1 = AstConv::ast_region_to_region(&icx, ®ion_pred.lifetime, None);
1502 for bound in ®ion_pred.bounds {
1503 let r2 = AstConv::ast_region_to_region(&icx, bound, None);
1504 let pred = ty::Binder(ty::OutlivesPredicate(r1, r2));
1505 predicates.push(ty::Predicate::RegionOutlives(pred))
1509 &hir::WherePredicate::EqPredicate(..) => {
1515 // Add predicates from associated type bounds.
1516 if let Some((self_trait_ref, trait_items)) = is_trait {
1517 predicates.extend(trait_items.iter().flat_map(|trait_item_ref| {
1518 let trait_item = tcx.hir.trait_item(trait_item_ref.id);
1519 let bounds = match trait_item.node {
1520 hir::TraitItemKind::Type(ref bounds, _) => bounds,
1522 return vec![].into_iter();
1526 let assoc_ty = tcx.mk_projection(
1527 tcx.hir.local_def_id(trait_item.id),
1528 self_trait_ref.substs,
1531 let bounds = compute_bounds(&ItemCtxt::new(tcx, def_id),
1534 SizedByDefault::Yes,
1537 bounds.predicates(tcx, assoc_ty).into_iter()
1541 // Subtle: before we store the predicates into the tcx, we
1542 // sort them so that predicates like `T: Foo<Item=U>` come
1543 // before uses of `U`. This avoids false ambiguity errors
1544 // in trait checking. See `setup_constraining_predicates`
1546 if let NodeItem(&Item { node: ItemImpl(..), .. }) = node {
1547 let self_ty = tcx.type_of(def_id);
1548 let trait_ref = tcx.impl_trait_ref(def_id);
1549 ctp::setup_constraining_predicates(tcx,
1552 &mut ctp::parameters_for_impl(self_ty, trait_ref));
1555 ty::GenericPredicates {
1556 parent: generics.parent,
1561 pub enum SizedByDefault { Yes, No, }
1563 /// Translate the AST's notion of ty param bounds (which are an enum consisting of a newtyped Ty or
1564 /// a region) to ty's notion of ty param bounds, which can either be user-defined traits, or the
1565 /// built-in trait (formerly known as kind): Send.
1566 pub fn compute_bounds<'gcx: 'tcx, 'tcx>(astconv: &AstConv<'gcx, 'tcx>,
1568 ast_bounds: &[hir::TyParamBound],
1569 sized_by_default: SizedByDefault,
1573 let mut region_bounds = vec![];
1574 let mut trait_bounds = vec![];
1575 for ast_bound in ast_bounds {
1577 hir::TraitTyParamBound(ref b, hir::TraitBoundModifier::None) => {
1578 trait_bounds.push(b);
1580 hir::TraitTyParamBound(_, hir::TraitBoundModifier::Maybe) => {}
1581 hir::RegionTyParamBound(ref l) => {
1582 region_bounds.push(l);
1587 let mut projection_bounds = vec![];
1589 let mut trait_bounds: Vec<_> = trait_bounds.iter().map(|&bound| {
1590 astconv.instantiate_poly_trait_ref(bound,
1592 &mut projection_bounds)
1595 let region_bounds = region_bounds.into_iter().map(|r| {
1596 astconv.ast_region_to_region(r, None)
1599 trait_bounds.sort_by(|a,b| a.def_id().cmp(&b.def_id()));
1601 let implicitly_sized = if let SizedByDefault::Yes = sized_by_default {
1602 !is_unsized(astconv, ast_bounds, span)
1615 /// Converts a specific TyParamBound from the AST into a set of
1616 /// predicates that apply to the self-type. A vector is returned
1617 /// because this can be anywhere from 0 predicates (`T:?Sized` adds no
1618 /// predicates) to 1 (`T:Foo`) to many (`T:Bar<X=i32>` adds `T:Bar`
1619 /// and `<T as Bar>::X == i32`).
1620 fn predicates_from_bound<'tcx>(astconv: &AstConv<'tcx, 'tcx>,
1622 bound: &hir::TyParamBound)
1623 -> Vec<ty::Predicate<'tcx>>
1626 hir::TraitTyParamBound(ref tr, hir::TraitBoundModifier::None) => {
1627 let mut projections = Vec::new();
1628 let pred = astconv.instantiate_poly_trait_ref(tr,
1631 projections.into_iter()
1632 .map(|p| p.to_predicate())
1633 .chain(Some(pred.to_predicate()))
1636 hir::RegionTyParamBound(ref lifetime) => {
1637 let region = astconv.ast_region_to_region(lifetime, None);
1638 let pred = ty::Binder(ty::OutlivesPredicate(param_ty, region));
1639 vec![ty::Predicate::TypeOutlives(pred)]
1641 hir::TraitTyParamBound(_, hir::TraitBoundModifier::Maybe) => {
1647 fn compute_sig_of_foreign_fn_decl<'a, 'tcx>(
1648 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1652 -> ty::PolyFnSig<'tcx>
1654 let fty = AstConv::ty_of_fn(&ItemCtxt::new(tcx, def_id), hir::Unsafety::Unsafe, abi, decl);
1656 // feature gate SIMD types in FFI, since I (huonw) am not sure the
1657 // ABIs are handled at all correctly.
1658 if abi != abi::Abi::RustIntrinsic && abi != abi::Abi::PlatformIntrinsic
1659 && !tcx.sess.features.borrow().simd_ffi {
1660 let check = |ast_ty: &hir::Ty, ty: Ty| {
1662 tcx.sess.struct_span_err(ast_ty.span,
1663 &format!("use of SIMD type `{}` in FFI is highly experimental and \
1664 may result in invalid code",
1665 tcx.hir.node_to_pretty_string(ast_ty.id)))
1666 .help("add #![feature(simd_ffi)] to the crate attributes to enable")
1670 for (input, ty) in decl.inputs.iter().zip(*fty.inputs().skip_binder()) {
1673 if let hir::Return(ref ty) = decl.output {
1674 check(&ty, *fty.output().skip_binder())
1681 fn is_foreign_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1684 match tcx.hir.get_if_local(def_id) {
1685 Some(hir_map::NodeForeignItem(..)) => true,
1687 _ => bug!("is_foreign_item applied to non-local def-id {:?}", def_id)
1691 fn is_default_impl<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1694 match tcx.hir.get_if_local(def_id) {
1695 Some(hir_map::NodeItem(&hir::Item { node: hir::ItemDefaultImpl(..), .. }))
1698 _ => bug!("is_default_impl applied to non-local def-id {:?}", def_id)