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.
15 The collect phase of type check has the job of visiting all items,
16 determining their type, and writing that type into the `tcx.tcache`
17 table. Despite its name, this table does not really operate as a
18 *cache*, at least not for the types of items defined within the
19 current crate: we assume that after the collect phase, the types of
20 all local items will be present in the table.
22 Unlike most of the types that are present in Rust, the types computed
23 for each item are in fact type schemes. This means that they are
24 generic types that may have type parameters. TypeSchemes are
25 represented by an instance of `ty::TypeScheme`. This combines the
26 core type along with a list of the bounds for each parameter. Type
27 parameters themselves are represented as `ty_param()` instances.
29 The phasing of type conversion is somewhat complicated. There is no
30 clear set of phases we can enforce (e.g., converting traits first,
31 then types, or something like that) because the user can introduce
32 arbitrary interdependencies. So instead we generally convert things
33 lazilly and on demand, and include logic that checks for cycles.
34 Demand is driven by calls to `AstConv::get_item_type_scheme` or
35 `AstConv::lookup_trait_def`.
37 Currently, we "convert" types and traits in three phases (note that
38 conversion only affects the types of items / enum variants / methods;
39 it does not e.g. compute the types of individual expressions):
45 Conversion itself is done by simply walking each of the items in turn
46 and invoking an appropriate function (e.g., `trait_def_of_item` or
47 `convert_item`). However, it is possible that while converting an
48 item, we may need to compute the *type scheme* or *trait definition*
51 There are some shortcomings in this design:
53 - Before walking the set of supertraits for a given trait, you must
54 call `ensure_super_predicates` on that trait def-id. Otherwise,
55 `lookup_super_predicates` will result in ICEs.
56 - Because the type scheme includes defaults, cycles through type
57 parameter defaults are illegal even if those defaults are never
58 employed. This is not necessarily a bug.
59 - The phasing of trait definitions before type definitions does not
60 seem to be necessary, sufficient, or particularly helpful, given that
61 processing a trait definition can trigger processing a type def and
62 vice versa. However, if I remove it, I get ICEs, so some more work is
63 needed in that area. -nmatsakis
67 use astconv::{self, AstConv, ty_of_arg, ast_ty_to_ty, ast_region_to_region};
69 use middle::def_id::DefId;
70 use constrained_type_params as ctp;
71 use middle::lang_items::SizedTraitLangItem;
72 use middle::free_region::FreeRegionMap;
74 use middle::resolve_lifetime;
75 use middle::const_eval::{self, ConstVal};
76 use middle::const_eval::EvalHint::UncheckedExprHint;
77 use middle::subst::{Substs, FnSpace, ParamSpace, SelfSpace, TypeSpace, VecPerParamSpace};
78 use middle::ty::{ToPredicate, ImplContainer, ImplOrTraitItemContainer, TraitContainer};
79 use middle::ty::{self, RegionEscape, ToPolyTraitRef, Ty, TypeScheme};
80 use middle::ty::{VariantKind};
81 use middle::ty::fold::{TypeFolder, TypeFoldable};
82 use middle::ty::util::IntTypeExt;
85 use rustc::front::map as hir_map;
86 use util::common::{ErrorReported, memoized};
87 use util::nodemap::{FnvHashMap, FnvHashSet};
90 use std::cell::{Cell, RefCell};
91 use std::collections::HashSet;
97 use syntax::codemap::Span;
98 use syntax::parse::token::special_idents;
100 use rustc_front::hir;
101 use rustc_front::visit;
102 use rustc_front::print::pprust;
104 ///////////////////////////////////////////////////////////////////////////
107 pub fn collect_item_types(tcx: &ty::ctxt) {
108 let ccx = &CrateCtxt { tcx: tcx, stack: RefCell::new(Vec::new()) };
110 let mut visitor = CollectTraitDefVisitor{ ccx: ccx };
111 visit::walk_crate(&mut visitor, ccx.tcx.map.krate());
113 let mut visitor = CollectItemTypesVisitor{ ccx: ccx };
114 visit::walk_crate(&mut visitor, ccx.tcx.map.krate());
117 ///////////////////////////////////////////////////////////////////////////
119 struct CrateCtxt<'a,'tcx:'a> {
120 tcx: &'a ty::ctxt<'tcx>,
122 // This stack is used to identify cycles in the user's source.
123 // Note that these cycles can cross multiple items.
124 stack: RefCell<Vec<AstConvRequest>>,
127 /// Context specific to some particular item. This is what implements
128 /// AstConv. It has information about the predicates that are defined
129 /// on the trait. Unfortunately, this predicate information is
130 /// available in various different forms at various points in the
131 /// process. So we can't just store a pointer to e.g. the AST or the
132 /// parsed ty form, we have to be more flexible. To this end, the
133 /// `ItemCtxt` is parameterized by a `GetTypeParameterBounds` object
134 /// that it uses to satisfy `get_type_parameter_bounds` requests.
135 /// This object might draw the information from the AST
136 /// (`hir::Generics`) or it might draw from a `ty::GenericPredicates`
137 /// or both (a tuple).
138 struct ItemCtxt<'a,'tcx:'a> {
139 ccx: &'a CrateCtxt<'a,'tcx>,
140 param_bounds: &'a (GetTypeParameterBounds<'tcx>+'a),
143 #[derive(Copy, Clone, PartialEq, Eq)]
144 enum AstConvRequest {
145 GetItemTypeScheme(DefId),
147 EnsureSuperPredicates(DefId),
148 GetTypeParameterBounds(ast::NodeId),
151 ///////////////////////////////////////////////////////////////////////////
152 // First phase: just collect *trait definitions* -- basically, the set
153 // of type parameters and supertraits. This is information we need to
154 // know later when parsing field defs.
156 struct CollectTraitDefVisitor<'a, 'tcx: 'a> {
157 ccx: &'a CrateCtxt<'a, 'tcx>
160 impl<'a, 'tcx, 'v> visit::Visitor<'v> for CollectTraitDefVisitor<'a, 'tcx> {
161 fn visit_item(&mut self, i: &hir::Item) {
163 hir::ItemTrait(..) => {
164 // computing the trait def also fills in the table
165 let _ = trait_def_of_item(self.ccx, i);
170 visit::walk_item(self, i);
174 ///////////////////////////////////////////////////////////////////////////
175 // Second phase: collection proper.
177 struct CollectItemTypesVisitor<'a, 'tcx: 'a> {
178 ccx: &'a CrateCtxt<'a, 'tcx>
181 impl<'a, 'tcx, 'v> visit::Visitor<'v> for CollectItemTypesVisitor<'a, 'tcx> {
182 fn visit_item(&mut self, i: &hir::Item) {
183 convert_item(self.ccx, i);
184 visit::walk_item(self, i);
186 fn visit_foreign_item(&mut self, i: &hir::ForeignItem) {
187 convert_foreign_item(self.ccx, i);
188 visit::walk_foreign_item(self, i);
192 ///////////////////////////////////////////////////////////////////////////
193 // Utility types and common code for the above passes.
195 impl<'a,'tcx> CrateCtxt<'a,'tcx> {
196 fn icx(&'a self, param_bounds: &'a GetTypeParameterBounds<'tcx>) -> ItemCtxt<'a,'tcx> {
197 ItemCtxt { ccx: self, param_bounds: param_bounds }
200 fn method_ty(&self, method_id: ast::NodeId) -> Rc<ty::Method<'tcx>> {
201 let def_id = self.tcx.map.local_def_id(method_id);
202 match *self.tcx.impl_or_trait_items.borrow().get(&def_id).unwrap() {
203 ty::MethodTraitItem(ref mty) => mty.clone(),
205 self.tcx.sess.bug(&format!("method with id {} has the wrong type", method_id));
210 fn cycle_check<F,R>(&self,
212 request: AstConvRequest,
214 -> Result<R,ErrorReported>
215 where F: FnOnce() -> Result<R,ErrorReported>
218 let mut stack = self.stack.borrow_mut();
219 match stack.iter().enumerate().rev().find(|&(_, r)| *r == request) {
222 let cycle = &stack[i..];
223 self.report_cycle(span, cycle);
224 return Err(ErrorReported);
232 self.stack.borrow_mut().pop();
236 fn report_cycle(&self,
238 cycle: &[AstConvRequest])
240 assert!(!cycle.is_empty());
243 span_err!(tcx.sess, span, E0391,
244 "unsupported cyclic reference between types/traits detected");
247 AstConvRequest::GetItemTypeScheme(def_id) |
248 AstConvRequest::GetTraitDef(def_id) => {
250 &format!("the cycle begins when processing `{}`...",
251 tcx.item_path_str(def_id)));
253 AstConvRequest::EnsureSuperPredicates(def_id) => {
255 &format!("the cycle begins when computing the supertraits of `{}`...",
256 tcx.item_path_str(def_id)));
258 AstConvRequest::GetTypeParameterBounds(id) => {
259 let def = tcx.type_parameter_def(id);
261 &format!("the cycle begins when computing the bounds \
262 for type parameter `{}`...",
267 for request in &cycle[1..] {
269 AstConvRequest::GetItemTypeScheme(def_id) |
270 AstConvRequest::GetTraitDef(def_id) => {
272 &format!("...which then requires processing `{}`...",
273 tcx.item_path_str(def_id)));
275 AstConvRequest::EnsureSuperPredicates(def_id) => {
277 &format!("...which then requires computing the supertraits of `{}`...",
278 tcx.item_path_str(def_id)));
280 AstConvRequest::GetTypeParameterBounds(id) => {
281 let def = tcx.type_parameter_def(id);
283 &format!("...which then requires computing the bounds \
284 for type parameter `{}`...",
291 AstConvRequest::GetItemTypeScheme(def_id) |
292 AstConvRequest::GetTraitDef(def_id) => {
294 &format!("...which then again requires processing `{}`, completing the cycle.",
295 tcx.item_path_str(def_id)));
297 AstConvRequest::EnsureSuperPredicates(def_id) => {
299 &format!("...which then again requires computing the supertraits of `{}`, \
300 completing the cycle.",
301 tcx.item_path_str(def_id)));
303 AstConvRequest::GetTypeParameterBounds(id) => {
304 let def = tcx.type_parameter_def(id);
306 &format!("...which then again requires computing the bounds \
307 for type parameter `{}`, completing the cycle.",
313 /// Loads the trait def for a given trait, returning ErrorReported if a cycle arises.
314 fn get_trait_def(&self, trait_id: DefId)
315 -> &'tcx ty::TraitDef<'tcx>
319 if let Some(trait_id) = tcx.map.as_local_node_id(trait_id) {
320 let item = match tcx.map.get(trait_id) {
321 hir_map::NodeItem(item) => item,
322 _ => tcx.sess.bug(&format!("get_trait_def({:?}): not an item", trait_id))
325 trait_def_of_item(self, &*item)
327 tcx.lookup_trait_def(trait_id)
331 /// Ensure that the (transitive) super predicates for
332 /// `trait_def_id` are available. This will report a cycle error
333 /// if a trait `X` (transitively) extends itself in some form.
334 fn ensure_super_predicates(&self, span: Span, trait_def_id: DefId)
335 -> Result<(), ErrorReported>
337 self.cycle_check(span, AstConvRequest::EnsureSuperPredicates(trait_def_id), || {
338 let def_ids = ensure_super_predicates_step(self, trait_def_id);
340 for def_id in def_ids {
341 try!(self.ensure_super_predicates(span, def_id));
349 impl<'a,'tcx> ItemCtxt<'a,'tcx> {
350 fn to_ty<RS:RegionScope>(&self, rs: &RS, ast_ty: &hir::Ty) -> Ty<'tcx> {
351 ast_ty_to_ty(self, rs, ast_ty)
355 impl<'a, 'tcx> AstConv<'tcx> for ItemCtxt<'a, 'tcx> {
356 fn tcx(&self) -> &ty::ctxt<'tcx> { self.ccx.tcx }
358 fn get_item_type_scheme(&self, span: Span, id: DefId)
359 -> Result<ty::TypeScheme<'tcx>, ErrorReported>
361 self.ccx.cycle_check(span, AstConvRequest::GetItemTypeScheme(id), || {
362 Ok(type_scheme_of_def_id(self.ccx, id))
366 fn get_trait_def(&self, span: Span, id: DefId)
367 -> Result<&'tcx ty::TraitDef<'tcx>, ErrorReported>
369 self.ccx.cycle_check(span, AstConvRequest::GetTraitDef(id), || {
370 Ok(self.ccx.get_trait_def(id))
374 fn ensure_super_predicates(&self,
377 -> Result<(), ErrorReported>
379 debug!("ensure_super_predicates(trait_def_id={:?})",
382 self.ccx.ensure_super_predicates(span, trait_def_id)
386 fn get_type_parameter_bounds(&self,
388 node_id: ast::NodeId)
389 -> Result<Vec<ty::PolyTraitRef<'tcx>>, ErrorReported>
391 self.ccx.cycle_check(span, AstConvRequest::GetTypeParameterBounds(node_id), || {
392 let v = self.param_bounds.get_type_parameter_bounds(self, span, node_id)
394 .filter_map(|p| p.to_opt_poly_trait_ref())
400 fn trait_defines_associated_type_named(&self,
402 assoc_name: ast::Name)
405 if let Some(trait_id) = self.tcx().map.as_local_node_id(trait_def_id) {
406 trait_defines_associated_type_named(self.ccx, trait_id, assoc_name)
408 let trait_def = self.tcx().lookup_trait_def(trait_def_id);
409 trait_def.associated_type_names.contains(&assoc_name)
414 _ty_param_def: Option<ty::TypeParameterDef<'tcx>>,
415 _substs: Option<&mut Substs<'tcx>>,
416 _space: Option<ParamSpace>,
417 span: Span) -> Ty<'tcx> {
418 span_err!(self.tcx().sess, span, E0121,
419 "the type placeholder `_` is not allowed within types on item signatures");
423 fn projected_ty(&self,
425 trait_ref: ty::TraitRef<'tcx>,
426 item_name: ast::Name)
429 self.tcx().mk_projection(trait_ref, item_name)
433 /// Interface used to find the bounds on a type parameter from within
434 /// an `ItemCtxt`. This allows us to use multiple kinds of sources.
435 trait GetTypeParameterBounds<'tcx> {
436 fn get_type_parameter_bounds(&self,
437 astconv: &AstConv<'tcx>,
439 node_id: ast::NodeId)
440 -> Vec<ty::Predicate<'tcx>>;
443 /// Find bounds from both elements of the tuple.
444 impl<'a,'b,'tcx,A,B> GetTypeParameterBounds<'tcx> for (&'a A,&'b B)
445 where A : GetTypeParameterBounds<'tcx>, B : GetTypeParameterBounds<'tcx>
447 fn get_type_parameter_bounds(&self,
448 astconv: &AstConv<'tcx>,
450 node_id: ast::NodeId)
451 -> Vec<ty::Predicate<'tcx>>
453 let mut v = self.0.get_type_parameter_bounds(astconv, span, node_id);
454 v.extend(self.1.get_type_parameter_bounds(astconv, span, node_id));
459 /// Empty set of bounds.
460 impl<'tcx> GetTypeParameterBounds<'tcx> for () {
461 fn get_type_parameter_bounds(&self,
462 _astconv: &AstConv<'tcx>,
464 _node_id: ast::NodeId)
465 -> Vec<ty::Predicate<'tcx>>
471 /// Find bounds from the parsed and converted predicates. This is
472 /// used when converting methods, because by that time the predicates
473 /// from the trait/impl have been fully converted.
474 impl<'tcx> GetTypeParameterBounds<'tcx> for ty::GenericPredicates<'tcx> {
475 fn get_type_parameter_bounds(&self,
476 astconv: &AstConv<'tcx>,
478 node_id: ast::NodeId)
479 -> Vec<ty::Predicate<'tcx>>
481 let def = astconv.tcx().type_parameter_def(node_id);
485 .filter(|predicate| {
487 ty::Predicate::Trait(ref data) => {
488 data.skip_binder().self_ty().is_param(def.space, def.index)
490 ty::Predicate::TypeOutlives(ref data) => {
491 data.skip_binder().0.is_param(def.space, def.index)
493 ty::Predicate::Equate(..) |
494 ty::Predicate::RegionOutlives(..) |
495 ty::Predicate::WellFormed(..) |
496 ty::Predicate::ObjectSafe(..) |
497 ty::Predicate::Projection(..) => {
507 /// Find bounds from hir::Generics. This requires scanning through the
508 /// AST. We do this to avoid having to convert *all* the bounds, which
509 /// would create artificial cycles. Instead we can only convert the
510 /// bounds for those a type parameter `X` if `X::Foo` is used.
511 impl<'tcx> GetTypeParameterBounds<'tcx> for hir::Generics {
512 fn get_type_parameter_bounds(&self,
513 astconv: &AstConv<'tcx>,
515 node_id: ast::NodeId)
516 -> Vec<ty::Predicate<'tcx>>
518 // In the AST, bounds can derive from two places. Either
519 // written inline like `<T:Foo>` or in a where clause like
522 let def = astconv.tcx().type_parameter_def(node_id);
523 let ty = astconv.tcx().mk_param_from_def(&def);
528 .filter(|p| p.id == node_id)
529 .flat_map(|p| p.bounds.iter())
530 .flat_map(|b| predicates_from_bound(astconv, ty, b));
532 let from_where_clauses =
536 .filter_map(|wp| match *wp {
537 hir::WherePredicate::BoundPredicate(ref bp) => Some(bp),
540 .filter(|bp| is_param(astconv.tcx(), &bp.bounded_ty, node_id))
541 .flat_map(|bp| bp.bounds.iter())
542 .flat_map(|b| predicates_from_bound(astconv, ty, b));
544 from_ty_params.chain(from_where_clauses).collect()
548 /// Tests whether this is the AST for a reference to the type
549 /// parameter with id `param_id`. We use this so as to avoid running
550 /// `ast_ty_to_ty`, because we want to avoid triggering an all-out
551 /// conversion of the type to avoid inducing unnecessary cycles.
552 fn is_param<'tcx>(tcx: &ty::ctxt<'tcx>,
554 param_id: ast::NodeId)
557 if let hir::TyPath(None, _) = ast_ty.node {
558 let path_res = *tcx.def_map.borrow().get(&ast_ty.id).unwrap();
559 match path_res.base_def {
560 def::DefSelfTy(Some(def_id), None) => {
561 path_res.depth == 0 && def_id == tcx.map.local_def_id(param_id)
563 def::DefTyParam(_, _, def_id, _) => {
564 path_res.depth == 0 && def_id == tcx.map.local_def_id(param_id)
576 fn convert_method<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
577 container: ImplOrTraitItemContainer,
578 sig: &hir::MethodSig,
581 vis: hir::Visibility,
582 untransformed_rcvr_ty: Ty<'tcx>,
583 rcvr_ty_generics: &ty::Generics<'tcx>,
584 rcvr_ty_predicates: &ty::GenericPredicates<'tcx>) {
585 let ty_generics = ty_generics_for_fn(ccx, &sig.generics, rcvr_ty_generics);
587 let ty_generic_predicates =
588 ty_generic_predicates_for_fn(ccx, &sig.generics, rcvr_ty_predicates);
590 let (fty, explicit_self_category) =
591 astconv::ty_of_method(&ccx.icx(&(rcvr_ty_predicates, &sig.generics)),
592 sig, untransformed_rcvr_ty);
594 let def_id = ccx.tcx.map.local_def_id(id);
595 let ty_method = ty::Method::new(name,
597 ty_generic_predicates,
599 explicit_self_category,
604 let fty = ccx.tcx.mk_fn(Some(def_id),
605 ccx.tcx.mk_bare_fn(ty_method.fty.clone()));
606 debug!("method {} (id {}) has type {:?}",
608 ccx.tcx.register_item_type(def_id, TypeScheme {
609 generics: ty_method.generics.clone(),
612 ccx.tcx.predicates.borrow_mut().insert(def_id, ty_method.predicates.clone());
614 write_ty_to_tcx(ccx.tcx, id, fty);
616 debug!("writing method type: def_id={:?} mty={:?}",
619 ccx.tcx.impl_or_trait_items.borrow_mut().insert(def_id,
620 ty::MethodTraitItem(Rc::new(ty_method)));
623 fn convert_field<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
624 struct_generics: &ty::Generics<'tcx>,
625 struct_predicates: &ty::GenericPredicates<'tcx>,
626 v: &hir::StructField,
627 ty_f: ty::FieldDefMaster<'tcx>)
629 let tt = ccx.icx(struct_predicates).to_ty(&ExplicitRscope, &*v.node.ty);
631 write_ty_to_tcx(ccx.tcx, v.node.id, tt);
633 /* add the field to the tcache */
634 ccx.tcx.register_item_type(ccx.tcx.map.local_def_id(v.node.id),
636 generics: struct_generics.clone(),
639 ccx.tcx.predicates.borrow_mut().insert(ccx.tcx.map.local_def_id(v.node.id),
640 struct_predicates.clone());
643 fn convert_associated_const<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
644 container: ImplOrTraitItemContainer,
647 vis: hir::Visibility,
651 ccx.tcx.predicates.borrow_mut().insert(ccx.tcx.map.local_def_id(id),
652 ty::GenericPredicates::empty());
654 write_ty_to_tcx(ccx.tcx, id, ty);
656 let associated_const = Rc::new(ty::AssociatedConst {
659 def_id: ccx.tcx.map.local_def_id(id),
660 container: container,
664 ccx.tcx.impl_or_trait_items.borrow_mut()
665 .insert(ccx.tcx.map.local_def_id(id), ty::ConstTraitItem(associated_const));
668 fn convert_associated_type<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
669 container: ImplOrTraitItemContainer,
672 vis: hir::Visibility,
673 ty: Option<Ty<'tcx>>)
675 let associated_type = Rc::new(ty::AssociatedType {
679 def_id: ccx.tcx.map.local_def_id(id),
682 ccx.tcx.impl_or_trait_items.borrow_mut()
683 .insert(ccx.tcx.map.local_def_id(id), ty::TypeTraitItem(associated_type));
686 fn convert_methods<'a,'tcx,'i,I>(ccx: &CrateCtxt<'a, 'tcx>,
687 container: ImplOrTraitItemContainer,
689 untransformed_rcvr_ty: Ty<'tcx>,
690 rcvr_ty_generics: &ty::Generics<'tcx>,
691 rcvr_ty_predicates: &ty::GenericPredicates<'tcx>)
692 where I: Iterator<Item=(&'i hir::MethodSig, ast::NodeId, ast::Name, hir::Visibility, Span)>
694 debug!("convert_methods(untransformed_rcvr_ty={:?}, rcvr_ty_generics={:?}, \
695 rcvr_ty_predicates={:?})",
696 untransformed_rcvr_ty,
700 for (sig, id, name, vis, _span) in methods {
707 untransformed_rcvr_ty,
713 fn ensure_no_ty_param_bounds(ccx: &CrateCtxt,
715 generics: &hir::Generics,
716 thing: &'static str) {
717 let mut warn = false;
719 for ty_param in generics.ty_params.iter() {
720 for bound in ty_param.bounds.iter() {
722 hir::TraitTyParamBound(..) => {
725 hir::RegionTyParamBound(..) => { }
731 // According to accepted RFC #XXX, we should
732 // eventually accept these, but it will not be
733 // part of this PR. Still, convert to warning to
734 // make bootstrapping easier.
735 span_warn!(ccx.tcx.sess, span, E0122,
736 "trait bounds are not (yet) enforced \
742 fn convert_item(ccx: &CrateCtxt, it: &hir::Item) {
744 debug!("convert: item {} with id {}", it.name, it.id);
746 // These don't define types.
747 hir::ItemExternCrate(_) | hir::ItemUse(_) |
748 hir::ItemForeignMod(_) | hir::ItemMod(_) => {
750 hir::ItemEnum(ref enum_definition, _) => {
751 let (scheme, predicates) = convert_typed_item(ccx, it);
752 write_ty_to_tcx(tcx, it.id, scheme.ty);
753 convert_enum_variant_types(ccx,
754 tcx.lookup_adt_def_master(ccx.tcx.map.local_def_id(it.id)),
757 &enum_definition.variants);
759 hir::ItemDefaultImpl(_, ref ast_trait_ref) => {
761 astconv::instantiate_mono_trait_ref(&ccx.icx(&()),
766 tcx.record_trait_has_default_impl(trait_ref.def_id);
768 tcx.impl_trait_refs.borrow_mut().insert(ccx.tcx.map.local_def_id(it.id),
776 // Create generics from the generics specified in the impl head.
777 debug!("convert: ast_generics={:?}", generics);
778 let ty_generics = ty_generics_for_type_or_impl(ccx, generics);
779 let ty_predicates = ty_generic_predicates_for_type_or_impl(ccx, generics);
781 debug!("convert: impl_bounds={:?}", ty_predicates);
783 let selfty = ccx.icx(&ty_predicates).to_ty(&ExplicitRscope, &**selfty);
784 write_ty_to_tcx(tcx, it.id, selfty);
786 tcx.register_item_type(ccx.tcx.map.local_def_id(it.id),
787 TypeScheme { generics: ty_generics.clone(),
789 tcx.predicates.borrow_mut().insert(ccx.tcx.map.local_def_id(it.id),
790 ty_predicates.clone());
791 if let &Some(ref ast_trait_ref) = opt_trait_ref {
792 tcx.impl_trait_refs.borrow_mut().insert(
793 ccx.tcx.map.local_def_id(it.id),
794 Some(astconv::instantiate_mono_trait_ref(&ccx.icx(&ty_predicates),
800 tcx.impl_trait_refs.borrow_mut().insert(ccx.tcx.map.local_def_id(it.id), None);
804 // If there is a trait reference, treat the methods as always public.
805 // This is to work around some incorrect behavior in privacy checking:
806 // when the method belongs to a trait, it should acquire the privacy
807 // from the trait, not the impl. Forcing the visibility to be public
808 // makes things sorta work.
809 let parent_visibility = if opt_trait_ref.is_some() {
815 // Convert all the associated consts.
816 // Also, check if there are any duplicate associated items
817 let mut seen_type_items = FnvHashSet();
818 let mut seen_value_items = FnvHashSet();
820 for impl_item in impl_items {
821 let seen_items = match impl_item.node {
822 hir::TypeImplItem(_) => &mut seen_type_items,
823 _ => &mut seen_value_items,
825 if !seen_items.insert(impl_item.name) {
826 let desc = match impl_item.node {
827 hir::ConstImplItem(_, _) => "associated constant",
828 hir::TypeImplItem(_) => "associated type",
829 hir::MethodImplItem(ref sig, _) =>
830 match sig.explicit_self.node {
831 hir::SelfStatic => "associated function",
836 span_err!(tcx.sess, impl_item.span, E0201, "duplicate {}", desc);
839 if let hir::ConstImplItem(ref ty, _) = impl_item.node {
840 let ty = ccx.icx(&ty_predicates)
841 .to_ty(&ExplicitRscope, &*ty);
842 tcx.register_item_type(ccx.tcx.map.local_def_id(impl_item.id),
844 generics: ty_generics.clone(),
847 convert_associated_const(ccx, ImplContainer(ccx.tcx.map.local_def_id(it.id)),
848 impl_item.name, impl_item.id,
849 impl_item.vis.inherit_from(parent_visibility),
850 ty, true /* has_value */);
854 // Convert all the associated types.
855 for impl_item in impl_items {
856 if let hir::TypeImplItem(ref ty) = impl_item.node {
857 if opt_trait_ref.is_none() {
858 span_err!(tcx.sess, impl_item.span, E0202,
859 "associated types are not allowed in inherent impls");
862 let typ = ccx.icx(&ty_predicates).to_ty(&ExplicitRscope, ty);
864 convert_associated_type(ccx, ImplContainer(ccx.tcx.map.local_def_id(it.id)),
865 impl_item.name, impl_item.id, impl_item.vis,
870 let methods = impl_items.iter().filter_map(|ii| {
871 if let hir::MethodImplItem(ref sig, _) = ii.node {
872 // if the method specifies a visibility, use that, otherwise
873 // inherit the visibility from the impl (so `foo` in `pub impl
874 // { fn foo(); }` is public, but private in `impl { fn
876 let method_vis = ii.vis.inherit_from(parent_visibility);
877 Some((sig, ii.id, ii.name, method_vis, ii.span))
883 ImplContainer(ccx.tcx.map.local_def_id(it.id)),
889 for impl_item in impl_items {
890 if let hir::MethodImplItem(ref sig, ref body) = impl_item.node {
891 let body_id = body.id;
892 check_method_self_type(ccx,
893 &BindingRscope::new(),
894 ccx.method_ty(impl_item.id),
901 enforce_impl_params_are_constrained(tcx,
903 ccx.tcx.map.local_def_id(it.id),
906 hir::ItemTrait(_, _, _, ref trait_items) => {
907 let trait_def = trait_def_of_item(ccx, it);
908 let _: Result<(), ErrorReported> = // any error is already reported, can ignore
909 ccx.ensure_super_predicates(it.span, ccx.tcx.map.local_def_id(it.id));
910 convert_trait_predicates(ccx, it);
911 let trait_predicates = tcx.lookup_predicates(ccx.tcx.map.local_def_id(it.id));
913 debug!("convert: trait_bounds={:?}", trait_predicates);
915 // Convert all the associated types.
916 for trait_item in trait_items {
917 match trait_item.node {
918 hir::ConstTraitItem(ref ty, ref default) => {
919 let ty = ccx.icx(&trait_predicates)
920 .to_ty(&ExplicitRscope, ty);
921 tcx.register_item_type(ccx.tcx.map.local_def_id(trait_item.id),
923 generics: trait_def.generics.clone(),
926 convert_associated_const(ccx,
927 TraitContainer(ccx.tcx.map.local_def_id(it.id)),
938 // Convert all the associated types.
939 for trait_item in trait_items {
940 match trait_item.node {
941 hir::TypeTraitItem(_, ref opt_ty) => {
942 let typ = opt_ty.as_ref().map({
943 |ty| ccx.icx(&trait_predicates).to_ty(&ExplicitRscope, &ty)
946 convert_associated_type(ccx,
947 TraitContainer(ccx.tcx.map.local_def_id(it.id)),
957 let methods = trait_items.iter().filter_map(|ti| {
958 let sig = match ti.node {
959 hir::MethodTraitItem(ref sig, _) => sig,
962 Some((sig, ti.id, ti.name, hir::Inherited, ti.span))
965 // Run convert_methods on the trait methods.
967 TraitContainer(ccx.tcx.map.local_def_id(it.id)),
973 // Add an entry mapping
974 let trait_item_def_ids = Rc::new(trait_items.iter().map(|trait_item| {
975 let def_id = ccx.tcx.map.local_def_id(trait_item.id);
976 match trait_item.node {
977 hir::ConstTraitItem(..) => {
978 ty::ConstTraitItemId(def_id)
980 hir::MethodTraitItem(..) => {
981 ty::MethodTraitItemId(def_id)
983 hir::TypeTraitItem(..) => {
984 ty::TypeTraitItemId(def_id)
988 tcx.trait_item_def_ids.borrow_mut().insert(ccx.tcx.map.local_def_id(it.id),
991 // This must be done after `collect_trait_methods` so that
992 // we have a method type stored for every method.
993 for trait_item in trait_items {
994 let sig = match trait_item.node {
995 hir::MethodTraitItem(ref sig, _) => sig,
998 check_method_self_type(ccx,
999 &BindingRscope::new(),
1000 ccx.method_ty(trait_item.id),
1006 hir::ItemStruct(ref struct_def, _) => {
1007 let (scheme, predicates) = convert_typed_item(ccx, it);
1008 write_ty_to_tcx(tcx, it.id, scheme.ty);
1010 let it_def_id = ccx.tcx.map.local_def_id(it.id);
1011 let variant = tcx.lookup_adt_def_master(it_def_id).struct_variant();
1013 for (f, ty_f) in struct_def.fields.iter().zip(variant.fields.iter()) {
1014 convert_field(ccx, &scheme.generics, &predicates, f, ty_f)
1017 if let Some(ctor_id) = struct_def.ctor_id {
1018 convert_variant_ctor(tcx, ctor_id, variant, scheme, predicates);
1021 hir::ItemTy(_, ref generics) => {
1022 ensure_no_ty_param_bounds(ccx, it.span, generics, "type");
1023 let (scheme, _) = convert_typed_item(ccx, it);
1024 write_ty_to_tcx(tcx, it.id, scheme.ty);
1027 // This call populates the type cache with the converted type
1028 // of the item in passing. All we have to do here is to write
1029 // it into the node type table.
1030 let (scheme, _) = convert_typed_item(ccx, it);
1031 write_ty_to_tcx(tcx, it.id, scheme.ty);
1036 fn convert_variant_ctor<'a, 'tcx>(tcx: &ty::ctxt<'tcx>,
1037 ctor_id: ast::NodeId,
1038 variant: ty::VariantDef<'tcx>,
1039 scheme: ty::TypeScheme<'tcx>,
1040 predicates: ty::GenericPredicates<'tcx>) {
1041 let ctor_ty = match variant.kind() {
1042 VariantKind::Unit | VariantKind::Dict => scheme.ty,
1043 VariantKind::Tuple => {
1044 let inputs: Vec<_> =
1047 .map(|field| field.unsubst_ty())
1049 tcx.mk_ctor_fn(tcx.map.local_def_id(ctor_id),
1054 write_ty_to_tcx(tcx, ctor_id, ctor_ty);
1055 tcx.predicates.borrow_mut().insert(tcx.map.local_def_id(ctor_id), predicates);
1056 tcx.register_item_type(tcx.map.local_def_id(ctor_id),
1058 generics: scheme.generics,
1063 fn convert_enum_variant_types<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
1064 def: ty::AdtDefMaster<'tcx>,
1065 scheme: ty::TypeScheme<'tcx>,
1066 predicates: ty::GenericPredicates<'tcx>,
1067 variants: &[P<hir::Variant>]) {
1069 let icx = ccx.icx(&predicates);
1071 // fill the field types
1072 for (variant, ty_variant) in variants.iter().zip(def.variants.iter()) {
1073 match variant.node.kind {
1074 hir::TupleVariantKind(ref args) => {
1075 let rs = ExplicitRscope;
1076 let input_tys: Vec<_> = args.iter().map(|va| icx.to_ty(&rs, &*va.ty)).collect();
1077 for (field, &ty) in ty_variant.fields.iter().zip(input_tys.iter()) {
1078 field.fulfill_ty(ty);
1082 hir::StructVariantKind(ref struct_def) => {
1083 for (f, ty_f) in struct_def.fields.iter().zip(ty_variant.fields.iter()) {
1084 convert_field(ccx, &scheme.generics, &predicates, f, ty_f)
1089 // Convert the ctor, if any. This also registers the variant as
1091 convert_variant_ctor(
1101 fn convert_struct_variant<'tcx>(tcx: &ty::ctxt<'tcx>,
1105 def: &hir::StructDef) -> ty::VariantDefData<'tcx, 'tcx> {
1106 let mut seen_fields: FnvHashMap<ast::Name, Span> = FnvHashMap();
1107 let fields = def.fields.iter().map(|f| {
1108 let fid = tcx.map.local_def_id(f.node.id);
1110 hir::NamedField(name, vis) => {
1111 let dup_span = seen_fields.get(&name).cloned();
1112 if let Some(prev_span) = dup_span {
1113 span_err!(tcx.sess, f.span, E0124,
1114 "field `{}` is already declared",
1116 span_note!(tcx.sess, prev_span, "previously declared here");
1118 seen_fields.insert(name, f.span);
1121 ty::FieldDefData::new(fid, name, vis)
1123 hir::UnnamedField(vis) => {
1124 ty::FieldDefData::new(fid, special_idents::unnamed_field.name, vis)
1128 ty::VariantDefData {
1136 fn convert_struct_def<'tcx>(tcx: &ty::ctxt<'tcx>,
1138 def: &hir::StructDef)
1139 -> ty::AdtDefMaster<'tcx>
1142 let did = tcx.map.local_def_id(it.id);
1143 let ctor_id = def.ctor_id.map_or(did,
1144 |ctor_id| tcx.map.local_def_id(ctor_id));
1147 ty::AdtKind::Struct,
1148 vec![convert_struct_variant(tcx, ctor_id, it.name, 0, def)]
1152 fn convert_enum_def<'tcx>(tcx: &ty::ctxt<'tcx>,
1155 -> ty::AdtDefMaster<'tcx>
1157 fn evaluate_disr_expr<'tcx>(tcx: &ty::ctxt<'tcx>,
1159 e: &hir::Expr) -> Option<ty::Disr> {
1160 debug!("disr expr, checking {}", pprust::expr_to_string(e));
1162 let hint = UncheckedExprHint(repr_ty);
1163 match const_eval::eval_const_expr_partial(tcx, e, hint) {
1164 Ok(ConstVal::Int(val)) => Some(val as ty::Disr),
1165 Ok(ConstVal::Uint(val)) => Some(val as ty::Disr),
1167 let sign_desc = if repr_ty.is_signed() {
1172 span_err!(tcx.sess, e.span, E0079,
1173 "expected {} integer constant",
1178 span_err!(tcx.sess, err.span, E0080,
1179 "constant evaluation error: {}",
1181 if !e.span.contains(err.span) {
1182 tcx.sess.span_note(e.span, "for enum discriminant here");
1189 fn report_discrim_overflow(tcx: &ty::ctxt,
1192 repr_type: attr::IntType,
1193 prev_val: ty::Disr) {
1194 let computed_value = repr_type.disr_wrap_incr(Some(prev_val));
1195 let computed_value = repr_type.disr_string(computed_value);
1196 let prev_val = repr_type.disr_string(prev_val);
1197 let repr_type = repr_type.to_ty(tcx);
1198 span_err!(tcx.sess, variant_span, E0370,
1199 "enum discriminant overflowed on value after {}: {}; \
1200 set explicitly via {} = {} if that is desired outcome",
1201 prev_val, repr_type, variant_name, computed_value);
1204 fn next_disr(tcx: &ty::ctxt,
1206 repr_type: attr::IntType,
1207 prev_disr_val: Option<ty::Disr>) -> Option<ty::Disr> {
1208 if let Some(prev_disr_val) = prev_disr_val {
1209 let result = repr_type.disr_incr(prev_disr_val);
1210 if let None = result {
1211 report_discrim_overflow(tcx, v.span, &v.node.name.as_str(),
1212 repr_type, prev_disr_val);
1216 Some(ty::INITIAL_DISCRIMINANT_VALUE)
1219 fn convert_enum_variant<'tcx>(tcx: &ty::ctxt<'tcx>,
1222 -> ty::VariantDefData<'tcx, 'tcx>
1224 let did = tcx.map.local_def_id(v.node.id);
1225 let name = v.node.name;
1227 hir::TupleVariantKind(ref va) => {
1228 ty::VariantDefData {
1232 fields: va.iter().map(|&hir::VariantArg { id, .. }| {
1233 ty::FieldDefData::new(
1234 tcx.map.local_def_id(id),
1235 special_idents::unnamed_field.name,
1236 hir::Visibility::Public
1241 hir::StructVariantKind(ref def) => {
1242 convert_struct_variant(tcx, did, name, disr, &def)
1246 let did = tcx.map.local_def_id(it.id);
1247 let repr_hints = tcx.lookup_repr_hints(did);
1248 let (repr_type, repr_type_ty) = tcx.enum_repr_type(repr_hints.get(0));
1249 let mut prev_disr = None;
1250 let variants = def.variants.iter().map(|v| {
1251 let disr = match v.node.disr_expr {
1252 Some(ref e) => evaluate_disr_expr(tcx, repr_type_ty, e),
1253 None => next_disr(tcx, v, repr_type, prev_disr)
1254 }.unwrap_or(repr_type.disr_wrap_incr(prev_disr));
1256 let v = convert_enum_variant(tcx, v, disr);
1257 prev_disr = Some(disr);
1260 tcx.intern_adt_def(tcx.map.local_def_id(it.id), ty::AdtKind::Enum, variants)
1263 /// Ensures that the super-predicates of the trait with def-id
1264 /// trait_def_id are converted and stored. This does NOT ensure that
1265 /// the transitive super-predicates are converted; that is the job of
1266 /// the `ensure_super_predicates()` method in the `AstConv` impl
1267 /// above. Returns a list of trait def-ids that must be ensured as
1268 /// well to guarantee that the transitive superpredicates are
1270 fn ensure_super_predicates_step(ccx: &CrateCtxt,
1271 trait_def_id: DefId)
1276 debug!("ensure_super_predicates_step(trait_def_id={:?})", trait_def_id);
1278 let trait_node_id = if let Some(n) = tcx.map.as_local_node_id(trait_def_id) {
1281 // If this trait comes from an external crate, then all of the
1282 // supertraits it may depend on also must come from external
1283 // crates, and hence all of them already have their
1284 // super-predicates "converted" (and available from crate
1285 // meta-data), so there is no need to transitively test them.
1289 let superpredicates = tcx.super_predicates.borrow().get(&trait_def_id).cloned();
1290 let superpredicates = superpredicates.unwrap_or_else(|| {
1291 let item = match ccx.tcx.map.get(trait_node_id) {
1292 hir_map::NodeItem(item) => item,
1293 _ => ccx.tcx.sess.bug(&format!("trait_node_id {} is not an item", trait_node_id))
1296 let (generics, bounds) = match item.node {
1297 hir::ItemTrait(_, ref generics, ref supertraits, _) => (generics, supertraits),
1298 _ => tcx.sess.span_bug(item.span,
1299 "ensure_super_predicates_step invoked on non-trait"),
1302 // In-scope when converting the superbounds for `Trait` are
1303 // that `Self:Trait` as well as any bounds that appear on the
1305 let trait_def = trait_def_of_item(ccx, item);
1306 let self_predicate = ty::GenericPredicates {
1307 predicates: VecPerParamSpace::new(vec![],
1308 vec![trait_def.trait_ref.to_predicate()],
1311 let scope = &(generics, &self_predicate);
1313 // Convert the bounds that follow the colon, e.g. `Bar+Zed` in `trait Foo : Bar+Zed`.
1314 let self_param_ty = tcx.mk_self_type();
1315 let superbounds1 = compute_bounds(&ccx.icx(scope),
1321 let superbounds1 = superbounds1.predicates(tcx, self_param_ty);
1323 // Convert any explicit superbounds in the where clause,
1324 // e.g. `trait Foo where Self : Bar`:
1325 let superbounds2 = generics.get_type_parameter_bounds(&ccx.icx(scope), item.span, item.id);
1327 // Combine the two lists to form the complete set of superbounds:
1328 let superbounds = superbounds1.into_iter().chain(superbounds2).collect();
1329 let superpredicates = ty::GenericPredicates {
1330 predicates: VecPerParamSpace::new(superbounds, vec![], vec![])
1332 debug!("superpredicates for trait {:?} = {:?}",
1333 tcx.map.local_def_id(item.id),
1336 tcx.super_predicates.borrow_mut().insert(trait_def_id, superpredicates.clone());
1341 let def_ids: Vec<_> = superpredicates.predicates
1343 .filter_map(|p| p.to_opt_poly_trait_ref())
1344 .map(|tr| tr.def_id())
1347 debug!("ensure_super_predicates_step: def_ids={:?}", def_ids);
1352 fn trait_def_of_item<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
1354 -> &'tcx ty::TraitDef<'tcx>
1356 let def_id = ccx.tcx.map.local_def_id(it.id);
1359 if let Some(def) = tcx.trait_defs.borrow().get(&def_id) {
1363 let (unsafety, generics, items) = match it.node {
1364 hir::ItemTrait(unsafety, ref generics, _, ref items) => (unsafety, generics, items),
1365 _ => tcx.sess.span_bug(it.span, "trait_def_of_item invoked on non-trait"),
1368 let paren_sugar = tcx.has_attr(def_id, "rustc_paren_sugar");
1369 if paren_sugar && !ccx.tcx.sess.features.borrow().unboxed_closures {
1370 ccx.tcx.sess.span_err(
1372 "the `#[rustc_paren_sugar]` attribute is a temporary means of controlling \
1373 which traits can use parenthetical notation");
1374 fileline_help!(ccx.tcx.sess, it.span,
1375 "add `#![feature(unboxed_closures)]` to \
1376 the crate attributes to use it");
1379 let substs = ccx.tcx.mk_substs(mk_trait_substs(ccx, generics));
1381 let ty_generics = ty_generics_for_trait(ccx, it.id, substs, generics);
1383 let associated_type_names: Vec<_> = items.iter().filter_map(|trait_item| {
1384 match trait_item.node {
1385 hir::TypeTraitItem(..) => Some(trait_item.name),
1390 let trait_ref = ty::TraitRef {
1395 let trait_def = ty::TraitDef {
1396 paren_sugar: paren_sugar,
1398 generics: ty_generics,
1399 trait_ref: trait_ref,
1400 associated_type_names: associated_type_names,
1401 nonblanket_impls: RefCell::new(FnvHashMap()),
1402 blanket_impls: RefCell::new(vec![]),
1403 flags: Cell::new(ty::TraitFlags::NO_TRAIT_FLAGS)
1406 return tcx.intern_trait_def(trait_def);
1408 fn mk_trait_substs<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
1409 generics: &hir::Generics)
1414 // Creates a no-op substitution for the trait's type parameters.
1419 .map(|(i, def)| ty::ReEarlyBound(ty::EarlyBoundRegion {
1420 def_id: tcx.map.local_def_id(def.lifetime.id),
1423 name: def.lifetime.name
1427 // Start with the generics in the type parameters...
1432 .map(|(i, def)| tcx.mk_param(TypeSpace,
1433 i as u32, def.name))
1436 // ...and also create the `Self` parameter.
1437 let self_ty = tcx.mk_self_type();
1439 Substs::new_trait(types, regions, self_ty)
1443 fn trait_defines_associated_type_named(ccx: &CrateCtxt,
1444 trait_node_id: ast::NodeId,
1445 assoc_name: ast::Name)
1448 let item = match ccx.tcx.map.get(trait_node_id) {
1449 hir_map::NodeItem(item) => item,
1450 _ => ccx.tcx.sess.bug(&format!("trait_node_id {} is not an item", trait_node_id))
1453 let trait_items = match item.node {
1454 hir::ItemTrait(_, _, _, ref trait_items) => trait_items,
1455 _ => ccx.tcx.sess.bug(&format!("trait_node_id {} is not a trait", trait_node_id))
1458 trait_items.iter().any(|trait_item| {
1459 match trait_item.node {
1460 hir::TypeTraitItem(..) => trait_item.name == assoc_name,
1466 fn convert_trait_predicates<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>, it: &hir::Item) {
1468 let trait_def = trait_def_of_item(ccx, it);
1470 let def_id = ccx.tcx.map.local_def_id(it.id);
1472 let (generics, items) = match it.node {
1473 hir::ItemTrait(_, ref generics, _, ref items) => (generics, items),
1477 &format!("trait_def_of_item invoked on {:?}", s));
1481 let super_predicates = ccx.tcx.lookup_super_predicates(def_id);
1483 // `ty_generic_predicates` below will consider the bounds on the type
1484 // parameters (including `Self`) and the explicit where-clauses,
1485 // but to get the full set of predicates on a trait we need to add
1486 // in the supertrait bounds and anything declared on the
1487 // associated types.
1488 let mut base_predicates = super_predicates;
1490 // Add in a predicate that `Self:Trait` (where `Trait` is the
1491 // current trait). This is needed for builtin bounds.
1492 let self_predicate = trait_def.trait_ref.to_poly_trait_ref().to_predicate();
1493 base_predicates.predicates.push(SelfSpace, self_predicate);
1495 // add in the explicit where-clauses
1496 let mut trait_predicates =
1497 ty_generic_predicates(ccx, TypeSpace, generics, &base_predicates);
1499 let assoc_predicates = predicates_for_associated_types(ccx,
1502 trait_def.trait_ref,
1504 trait_predicates.predicates.extend(TypeSpace, assoc_predicates.into_iter());
1506 let prev_predicates = tcx.predicates.borrow_mut().insert(def_id, trait_predicates);
1507 assert!(prev_predicates.is_none());
1511 fn predicates_for_associated_types<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
1512 ast_generics: &hir::Generics,
1513 trait_predicates: &ty::GenericPredicates<'tcx>,
1514 self_trait_ref: ty::TraitRef<'tcx>,
1515 trait_items: &[P<hir::TraitItem>])
1516 -> Vec<ty::Predicate<'tcx>>
1518 trait_items.iter().flat_map(|trait_item| {
1519 let bounds = match trait_item.node {
1520 hir::TypeTraitItem(ref bounds, _) => bounds,
1522 return vec!().into_iter();
1526 let assoc_ty = ccx.tcx.mk_projection(self_trait_ref,
1529 let bounds = compute_bounds(&ccx.icx(&(ast_generics, trait_predicates)),
1532 SizedByDefault::Yes,
1535 bounds.predicates(ccx.tcx, assoc_ty).into_iter()
1540 fn type_scheme_of_def_id<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
1542 -> ty::TypeScheme<'tcx>
1544 if let Some(node_id) = ccx.tcx.map.as_local_node_id(def_id) {
1545 match ccx.tcx.map.find(node_id) {
1546 Some(hir_map::NodeItem(item)) => {
1547 type_scheme_of_item(ccx, &*item)
1549 Some(hir_map::NodeForeignItem(foreign_item)) => {
1550 let abi = ccx.tcx.map.get_foreign_abi(node_id);
1551 type_scheme_of_foreign_item(ccx, &*foreign_item, abi)
1554 ccx.tcx.sess.bug(&format!("unexpected sort of node \
1555 in get_item_type_scheme(): {:?}",
1560 ccx.tcx.lookup_item_type(def_id)
1564 fn type_scheme_of_item<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
1566 -> ty::TypeScheme<'tcx>
1568 memoized(&ccx.tcx.tcache,
1569 ccx.tcx.map.local_def_id(it.id),
1570 |_| compute_type_scheme_of_item(ccx, it))
1573 fn compute_type_scheme_of_item<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
1575 -> ty::TypeScheme<'tcx>
1579 hir::ItemStatic(ref t, _, _) | hir::ItemConst(ref t, _) => {
1580 let ty = ccx.icx(&()).to_ty(&ExplicitRscope, &**t);
1581 ty::TypeScheme { ty: ty, generics: ty::Generics::empty() }
1583 hir::ItemFn(ref decl, unsafety, _, abi, ref generics, _) => {
1584 let ty_generics = ty_generics_for_fn(ccx, generics, &ty::Generics::empty());
1585 let tofd = astconv::ty_of_bare_fn(&ccx.icx(generics), unsafety, abi, &**decl);
1586 let ty = tcx.mk_fn(Some(ccx.tcx.map.local_def_id(it.id)), tcx.mk_bare_fn(tofd));
1587 ty::TypeScheme { ty: ty, generics: ty_generics }
1589 hir::ItemTy(ref t, ref generics) => {
1590 let ty_generics = ty_generics_for_type_or_impl(ccx, generics);
1591 let ty = ccx.icx(generics).to_ty(&ExplicitRscope, &**t);
1592 ty::TypeScheme { ty: ty, generics: ty_generics }
1594 hir::ItemEnum(ref ei, ref generics) => {
1595 let ty_generics = ty_generics_for_type_or_impl(ccx, generics);
1596 let substs = mk_item_substs(ccx, &ty_generics);
1597 let def = convert_enum_def(tcx, it, ei);
1598 let t = tcx.mk_enum(def, tcx.mk_substs(substs));
1599 ty::TypeScheme { ty: t, generics: ty_generics }
1601 hir::ItemStruct(ref si, ref generics) => {
1602 let ty_generics = ty_generics_for_type_or_impl(ccx, generics);
1603 let substs = mk_item_substs(ccx, &ty_generics);
1604 let def = convert_struct_def(tcx, it, si);
1605 let t = tcx.mk_struct(def, tcx.mk_substs(substs));
1606 ty::TypeScheme { ty: t, generics: ty_generics }
1608 hir::ItemDefaultImpl(..) |
1609 hir::ItemTrait(..) |
1612 hir::ItemForeignMod(..) |
1613 hir::ItemExternCrate(..) |
1614 hir::ItemUse(..) => {
1617 &format!("compute_type_scheme_of_item: unexpected item type: {:?}",
1623 fn convert_typed_item<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
1625 -> (ty::TypeScheme<'tcx>, ty::GenericPredicates<'tcx>)
1629 let tag = type_scheme_of_item(ccx, it);
1630 let scheme = TypeScheme { generics: tag.generics, ty: tag.ty };
1631 let predicates = match it.node {
1632 hir::ItemStatic(..) | hir::ItemConst(..) => {
1633 ty::GenericPredicates::empty()
1635 hir::ItemFn(_, _, _, _, ref ast_generics, _) => {
1636 ty_generic_predicates_for_fn(ccx, ast_generics, &ty::GenericPredicates::empty())
1638 hir::ItemTy(_, ref generics) => {
1639 ty_generic_predicates_for_type_or_impl(ccx, generics)
1641 hir::ItemEnum(_, ref generics) => {
1642 ty_generic_predicates_for_type_or_impl(ccx, generics)
1644 hir::ItemStruct(_, ref generics) => {
1645 ty_generic_predicates_for_type_or_impl(ccx, generics)
1647 hir::ItemDefaultImpl(..) |
1648 hir::ItemTrait(..) |
1649 hir::ItemExternCrate(..) |
1653 hir::ItemForeignMod(..) => {
1656 &format!("compute_type_scheme_of_item: unexpected item type: {:?}",
1661 let prev_predicates = tcx.predicates.borrow_mut().insert(ccx.tcx.map.local_def_id(it.id),
1662 predicates.clone());
1663 assert!(prev_predicates.is_none());
1666 if tcx.has_attr(ccx.tcx.map.local_def_id(it.id), "rustc_object_lifetime_default") {
1667 let object_lifetime_default_reprs: String =
1668 scheme.generics.types.iter()
1669 .map(|t| match t.object_lifetime_default {
1670 ty::ObjectLifetimeDefault::Specific(r) => r.to_string(),
1671 d => format!("{:?}", d),
1673 .collect::<Vec<String>>()
1676 tcx.sess.span_err(it.span, &object_lifetime_default_reprs);
1679 return (scheme, predicates);
1682 fn type_scheme_of_foreign_item<'a, 'tcx>(
1683 ccx: &CrateCtxt<'a, 'tcx>,
1684 it: &hir::ForeignItem,
1686 -> ty::TypeScheme<'tcx>
1688 memoized(&ccx.tcx.tcache,
1689 ccx.tcx.map.local_def_id(it.id),
1690 |_| compute_type_scheme_of_foreign_item(ccx, it, abi))
1693 fn compute_type_scheme_of_foreign_item<'a, 'tcx>(
1694 ccx: &CrateCtxt<'a, 'tcx>,
1695 it: &hir::ForeignItem,
1697 -> ty::TypeScheme<'tcx>
1700 hir::ForeignItemFn(ref fn_decl, ref generics) => {
1701 compute_type_scheme_of_foreign_fn_decl(ccx, fn_decl, generics, abi)
1703 hir::ForeignItemStatic(ref t, _) => {
1705 generics: ty::Generics::empty(),
1706 ty: ast_ty_to_ty(&ccx.icx(&()), &ExplicitRscope, t)
1712 fn convert_foreign_item<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
1713 it: &hir::ForeignItem)
1715 // For reasons I cannot fully articulate, I do so hate the AST
1716 // map, and I regard each time that I use it as a personal and
1717 // moral failing, but at the moment it seems like the only
1718 // convenient way to extract the ABI. - ndm
1720 let abi = tcx.map.get_foreign_abi(it.id);
1722 let scheme = type_scheme_of_foreign_item(ccx, it, abi);
1723 write_ty_to_tcx(ccx.tcx, it.id, scheme.ty);
1725 let predicates = match it.node {
1726 hir::ForeignItemFn(_, ref generics) => {
1727 ty_generic_predicates_for_fn(ccx, generics, &ty::GenericPredicates::empty())
1729 hir::ForeignItemStatic(..) => {
1730 ty::GenericPredicates::empty()
1734 let prev_predicates = tcx.predicates.borrow_mut().insert(ccx.tcx.map.local_def_id(it.id),
1736 assert!(prev_predicates.is_none());
1739 fn ty_generics_for_type_or_impl<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
1740 generics: &hir::Generics)
1741 -> ty::Generics<'tcx> {
1742 ty_generics(ccx, TypeSpace, generics, &ty::Generics::empty())
1745 fn ty_generic_predicates_for_type_or_impl<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
1746 generics: &hir::Generics)
1747 -> ty::GenericPredicates<'tcx>
1749 ty_generic_predicates(ccx, TypeSpace, generics, &ty::GenericPredicates::empty())
1752 fn ty_generics_for_trait<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
1753 trait_id: ast::NodeId,
1754 substs: &'tcx Substs<'tcx>,
1755 ast_generics: &hir::Generics)
1756 -> ty::Generics<'tcx>
1758 debug!("ty_generics_for_trait(trait_id={:?}, substs={:?})",
1759 ccx.tcx.map.local_def_id(trait_id), substs);
1761 let mut generics = ty_generics_for_type_or_impl(ccx, ast_generics);
1763 // Add in the self type parameter.
1765 // Something of a hack: use the node id for the trait, also as
1766 // the node id for the Self type parameter.
1767 let param_id = trait_id;
1769 let parent = ccx.tcx.map.get_parent(param_id);
1771 let def = ty::TypeParameterDef {
1774 name: special_idents::type_self.name,
1775 def_id: ccx.tcx.map.local_def_id(param_id),
1776 default_def_id: ccx.tcx.map.local_def_id(parent),
1778 object_lifetime_default: ty::ObjectLifetimeDefault::BaseDefault,
1781 ccx.tcx.ty_param_defs.borrow_mut().insert(param_id, def.clone());
1783 generics.types.push(SelfSpace, def);
1788 fn ty_generics_for_fn<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
1789 generics: &hir::Generics,
1790 base_generics: &ty::Generics<'tcx>)
1791 -> ty::Generics<'tcx>
1793 ty_generics(ccx, FnSpace, generics, base_generics)
1796 fn ty_generic_predicates_for_fn<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
1797 generics: &hir::Generics,
1798 base_predicates: &ty::GenericPredicates<'tcx>)
1799 -> ty::GenericPredicates<'tcx>
1801 ty_generic_predicates(ccx, FnSpace, generics, base_predicates)
1804 // Add the Sized bound, unless the type parameter is marked as `?Sized`.
1805 fn add_unsized_bound<'tcx>(astconv: &AstConv<'tcx>,
1806 bounds: &mut ty::BuiltinBounds,
1807 ast_bounds: &[hir::TyParamBound],
1810 let tcx = astconv.tcx();
1812 // Try to find an unbound in bounds.
1813 let mut unbound = None;
1814 for ab in ast_bounds {
1815 if let &hir::TraitTyParamBound(ref ptr, hir::TraitBoundModifier::Maybe) = ab {
1816 if unbound.is_none() {
1817 assert!(ptr.bound_lifetimes.is_empty());
1818 unbound = Some(ptr.trait_ref.clone());
1820 span_err!(tcx.sess, span, E0203,
1821 "type parameter has more than one relaxed default \
1822 bound, only one is supported");
1827 let kind_id = tcx.lang_items.require(SizedTraitLangItem);
1830 // FIXME(#8559) currently requires the unbound to be built-in.
1831 let trait_def_id = tcx.trait_ref_to_def_id(tpb);
1833 Ok(kind_id) if trait_def_id != kind_id => {
1834 tcx.sess.span_warn(span,
1835 "default bound relaxed for a type parameter, but \
1836 this does nothing because the given bound is not \
1837 a default. Only `?Sized` is supported");
1838 tcx.try_add_builtin_trait(kind_id, bounds);
1843 _ if kind_id.is_ok() => {
1844 tcx.try_add_builtin_trait(kind_id.unwrap(), bounds);
1846 // No lang item for Sized, so we can't add it as a bound.
1851 /// Returns the early-bound lifetimes declared in this generics
1852 /// listing. For anything other than fns/methods, this is just all
1853 /// the lifetimes that are declared. For fns or methods, we have to
1854 /// screen out those that do not appear in any where-clauses etc using
1855 /// `resolve_lifetime::early_bound_lifetimes`.
1856 fn early_bound_lifetimes_from_generics(space: ParamSpace,
1857 ast_generics: &hir::Generics)
1858 -> Vec<hir::LifetimeDef>
1861 SelfSpace | TypeSpace => ast_generics.lifetimes.to_vec(),
1862 FnSpace => resolve_lifetime::early_bound_lifetimes(ast_generics),
1866 fn ty_generic_predicates<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
1868 ast_generics: &hir::Generics,
1869 base_predicates: &ty::GenericPredicates<'tcx>)
1870 -> ty::GenericPredicates<'tcx>
1873 let mut result = base_predicates.clone();
1875 // Collect the predicates that were written inline by the user on each
1876 // type parameter (e.g., `<T:Foo>`).
1877 for (index, param) in ast_generics.ty_params.iter().enumerate() {
1878 let index = index as u32;
1879 let param_ty = ty::ParamTy::new(space, index, param.name).to_ty(ccx.tcx);
1880 let bounds = compute_bounds(&ccx.icx(&(base_predicates, ast_generics)),
1883 SizedByDefault::Yes,
1885 let predicates = bounds.predicates(ccx.tcx, param_ty);
1886 result.predicates.extend(space, predicates.into_iter());
1889 // Collect the region predicates that were declared inline as
1890 // well. In the case of parameters declared on a fn or method, we
1891 // have to be careful to only iterate over early-bound regions.
1892 let early_lifetimes = early_bound_lifetimes_from_generics(space, ast_generics);
1893 for (index, param) in early_lifetimes.iter().enumerate() {
1894 let index = index as u32;
1895 let def_id = tcx.map.local_def_id(param.lifetime.id);
1897 ty::ReEarlyBound(ty::EarlyBoundRegion {
1901 name: param.lifetime.name
1903 for bound in ¶m.bounds {
1904 let bound_region = ast_region_to_region(ccx.tcx, bound);
1905 let outlives = ty::Binder(ty::OutlivesPredicate(region, bound_region));
1906 result.predicates.push(space, outlives.to_predicate());
1910 // Add in the bounds that appear in the where-clause
1911 let where_clause = &ast_generics.where_clause;
1912 for predicate in &where_clause.predicates {
1914 &hir::WherePredicate::BoundPredicate(ref bound_pred) => {
1915 let ty = ast_ty_to_ty(&ccx.icx(&(base_predicates, ast_generics)),
1917 &*bound_pred.bounded_ty);
1919 for bound in bound_pred.bounds.iter() {
1921 &hir::TyParamBound::TraitTyParamBound(ref poly_trait_ref, _) => {
1922 let mut projections = Vec::new();
1925 conv_poly_trait_ref(&ccx.icx(&(base_predicates, ast_generics)),
1930 result.predicates.push(space, trait_ref.to_predicate());
1932 for projection in &projections {
1933 result.predicates.push(space, projection.to_predicate());
1937 &hir::TyParamBound::RegionTyParamBound(ref lifetime) => {
1938 let region = ast_region_to_region(tcx, lifetime);
1939 let pred = ty::Binder(ty::OutlivesPredicate(ty, region));
1940 result.predicates.push(space, ty::Predicate::TypeOutlives(pred))
1946 &hir::WherePredicate::RegionPredicate(ref region_pred) => {
1947 let r1 = ast_region_to_region(tcx, ®ion_pred.lifetime);
1948 for bound in ®ion_pred.bounds {
1949 let r2 = ast_region_to_region(tcx, bound);
1950 let pred = ty::Binder(ty::OutlivesPredicate(r1, r2));
1951 result.predicates.push(space, ty::Predicate::RegionOutlives(pred))
1955 &hir::WherePredicate::EqPredicate(ref eq_pred) => {
1957 tcx.sess.span_bug(eq_pred.span,
1958 "Equality constraints are not yet \
1959 implemented (#20041)")
1967 fn ty_generics<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
1969 ast_generics: &hir::Generics,
1970 base_generics: &ty::Generics<'tcx>)
1971 -> ty::Generics<'tcx>
1974 let mut result = base_generics.clone();
1976 let early_lifetimes = early_bound_lifetimes_from_generics(space, ast_generics);
1977 for (i, l) in early_lifetimes.iter().enumerate() {
1978 let bounds = l.bounds.iter()
1979 .map(|l| ast_region_to_region(tcx, l))
1981 let def = ty::RegionParameterDef { name: l.lifetime.name,
1984 def_id: ccx.tcx.map.local_def_id(l.lifetime.id),
1986 result.regions.push(space, def);
1989 assert!(result.types.is_empty_in(space));
1991 // Now create the real type parameters.
1992 for i in 0..ast_generics.ty_params.len() {
1993 let def = get_or_create_type_parameter_def(ccx, ast_generics, space, i as u32);
1994 debug!("ty_generics: def for type param: {:?}, {:?}", def, space);
1995 result.types.push(space, def);
2001 fn convert_default_type_parameter<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
2007 let ty = ast_ty_to_ty(&ccx.icx(&()), &ExplicitRscope, &path);
2009 for leaf_ty in ty.walk() {
2010 if let ty::TyParam(p) = leaf_ty.sty {
2011 if p.space == space && p.idx >= index {
2012 span_err!(ccx.tcx.sess, path.span, E0128,
2013 "type parameters with a default cannot use \
2014 forward declared identifiers");
2016 return ccx.tcx.types.err
2024 fn get_or_create_type_parameter_def<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
2025 ast_generics: &hir::Generics,
2028 -> ty::TypeParameterDef<'tcx>
2030 let param = &ast_generics.ty_params[index as usize];
2033 match tcx.ty_param_defs.borrow().get(¶m.id) {
2034 Some(d) => { return d.clone(); }
2038 let default = param.default.as_ref().map(
2039 |def| convert_default_type_parameter(ccx, def, space, index)
2042 let object_lifetime_default =
2043 compute_object_lifetime_default(ccx, param.id,
2044 ¶m.bounds, &ast_generics.where_clause);
2046 let parent = tcx.map.get_parent(param.id);
2048 let def = ty::TypeParameterDef {
2052 def_id: ccx.tcx.map.local_def_id(param.id),
2053 default_def_id: ccx.tcx.map.local_def_id(parent),
2055 object_lifetime_default: object_lifetime_default,
2058 tcx.ty_param_defs.borrow_mut().insert(param.id, def.clone());
2063 /// Scan the bounds and where-clauses on a parameter to extract bounds
2064 /// of the form `T:'a` so as to determine the `ObjectLifetimeDefault`.
2065 /// This runs as part of computing the minimal type scheme, so we
2066 /// intentionally avoid just asking astconv to convert all the where
2067 /// clauses into a `ty::Predicate`. This is because that could induce
2068 /// artificial cycles.
2069 fn compute_object_lifetime_default<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
2070 param_id: ast::NodeId,
2071 param_bounds: &[hir::TyParamBound],
2072 where_clause: &hir::WhereClause)
2073 -> ty::ObjectLifetimeDefault
2075 let inline_bounds = from_bounds(ccx, param_bounds);
2076 let where_bounds = from_predicates(ccx, param_id, &where_clause.predicates);
2077 let all_bounds: HashSet<_> = inline_bounds.into_iter()
2078 .chain(where_bounds)
2080 return if all_bounds.len() > 1 {
2081 ty::ObjectLifetimeDefault::Ambiguous
2082 } else if all_bounds.len() == 0 {
2083 ty::ObjectLifetimeDefault::BaseDefault
2085 ty::ObjectLifetimeDefault::Specific(
2086 all_bounds.into_iter().next().unwrap())
2089 fn from_bounds<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
2090 bounds: &[hir::TyParamBound])
2094 .filter_map(|bound| {
2096 hir::TraitTyParamBound(..) =>
2098 hir::RegionTyParamBound(ref lifetime) =>
2099 Some(astconv::ast_region_to_region(ccx.tcx, lifetime)),
2105 fn from_predicates<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
2106 param_id: ast::NodeId,
2107 predicates: &[hir::WherePredicate])
2111 .flat_map(|predicate| {
2113 hir::WherePredicate::BoundPredicate(ref data) => {
2114 if data.bound_lifetimes.is_empty() &&
2115 is_param(ccx.tcx, &data.bounded_ty, param_id)
2117 from_bounds(ccx, &data.bounds).into_iter()
2119 Vec::new().into_iter()
2122 hir::WherePredicate::RegionPredicate(..) |
2123 hir::WherePredicate::EqPredicate(..) => {
2124 Vec::new().into_iter()
2132 enum SizedByDefault { Yes, No, }
2134 /// Translate the AST's notion of ty param bounds (which are an enum consisting of a newtyped Ty or
2135 /// a region) to ty's notion of ty param bounds, which can either be user-defined traits, or the
2136 /// built-in trait (formerly known as kind): Send.
2137 fn compute_bounds<'tcx>(astconv: &AstConv<'tcx>,
2138 param_ty: ty::Ty<'tcx>,
2139 ast_bounds: &[hir::TyParamBound],
2140 sized_by_default: SizedByDefault,
2142 -> astconv::Bounds<'tcx>
2145 conv_param_bounds(astconv,
2150 if let SizedByDefault::Yes = sized_by_default {
2151 add_unsized_bound(astconv,
2152 &mut bounds.builtin_bounds,
2157 bounds.trait_bounds.sort_by(|a,b| a.def_id().cmp(&b.def_id()));
2162 /// Converts a specific TyParamBound from the AST into a set of
2163 /// predicates that apply to the self-type. A vector is returned
2164 /// because this can be anywhere from 0 predicates (`T:?Sized` adds no
2165 /// predicates) to 1 (`T:Foo`) to many (`T:Bar<X=i32>` adds `T:Bar`
2166 /// and `<T as Bar>::X == i32`).
2167 fn predicates_from_bound<'tcx>(astconv: &AstConv<'tcx>,
2169 bound: &hir::TyParamBound)
2170 -> Vec<ty::Predicate<'tcx>>
2173 hir::TraitTyParamBound(ref tr, hir::TraitBoundModifier::None) => {
2174 let mut projections = Vec::new();
2175 let pred = conv_poly_trait_ref(astconv, param_ty, tr, &mut projections);
2176 projections.into_iter()
2177 .map(|p| p.to_predicate())
2178 .chain(Some(pred.to_predicate()))
2181 hir::RegionTyParamBound(ref lifetime) => {
2182 let region = ast_region_to_region(astconv.tcx(), lifetime);
2183 let pred = ty::Binder(ty::OutlivesPredicate(param_ty, region));
2184 vec![ty::Predicate::TypeOutlives(pred)]
2186 hir::TraitTyParamBound(_, hir::TraitBoundModifier::Maybe) => {
2192 fn conv_poly_trait_ref<'tcx>(astconv: &AstConv<'tcx>,
2194 trait_ref: &hir::PolyTraitRef,
2195 projections: &mut Vec<ty::PolyProjectionPredicate<'tcx>>)
2196 -> ty::PolyTraitRef<'tcx>
2198 astconv::instantiate_poly_trait_ref(astconv,
2205 fn conv_param_bounds<'a,'tcx>(astconv: &AstConv<'tcx>,
2207 param_ty: ty::Ty<'tcx>,
2208 ast_bounds: &[hir::TyParamBound])
2209 -> astconv::Bounds<'tcx>
2211 let tcx = astconv.tcx();
2212 let astconv::PartitionedBounds {
2216 } = astconv::partition_bounds(tcx, span, &ast_bounds);
2218 let mut projection_bounds = Vec::new();
2220 let trait_bounds: Vec<ty::PolyTraitRef> =
2222 .map(|bound| conv_poly_trait_ref(astconv,
2225 &mut projection_bounds))
2228 let region_bounds: Vec<ty::Region> =
2229 region_bounds.into_iter()
2230 .map(|r| ast_region_to_region(tcx, r))
2234 region_bounds: region_bounds,
2235 builtin_bounds: builtin_bounds,
2236 trait_bounds: trait_bounds,
2237 projection_bounds: projection_bounds,
2241 fn compute_type_scheme_of_foreign_fn_decl<'a, 'tcx>(
2242 ccx: &CrateCtxt<'a, 'tcx>,
2244 ast_generics: &hir::Generics,
2246 -> ty::TypeScheme<'tcx>
2248 for i in &decl.inputs {
2249 match (*i).pat.node {
2250 hir::PatIdent(_, _, _) => (),
2251 hir::PatWild(hir::PatWildSingle) => (),
2253 span_err!(ccx.tcx.sess, (*i).pat.span, E0130,
2254 "patterns aren't allowed in foreign function declarations");
2259 let ty_generics = ty_generics_for_fn(ccx, ast_generics, &ty::Generics::empty());
2261 let rb = BindingRscope::new();
2262 let input_tys = decl.inputs
2264 .map(|a| ty_of_arg(&ccx.icx(ast_generics), &rb, a, None))
2267 let output = match decl.output {
2268 hir::Return(ref ty) =>
2269 ty::FnConverging(ast_ty_to_ty(&ccx.icx(ast_generics), &rb, &**ty)),
2270 hir::DefaultReturn(..) =>
2271 ty::FnConverging(ccx.tcx.mk_nil()),
2272 hir::NoReturn(..) =>
2276 let t_fn = ccx.tcx.mk_fn(None,
2277 ccx.tcx.mk_bare_fn(ty::BareFnTy {
2279 unsafety: hir::Unsafety::Unsafe,
2280 sig: ty::Binder(ty::FnSig {inputs: input_tys,
2282 variadic: decl.variadic}),
2286 generics: ty_generics,
2291 fn mk_item_substs<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
2292 ty_generics: &ty::Generics<'tcx>)
2296 ty_generics.types.map(
2297 |def| ccx.tcx.mk_param_from_def(def));
2300 ty_generics.regions.map(
2301 |def| def.to_early_bound_region());
2303 Substs::new(types, regions)
2306 /// Verifies that the explicit self type of a method matches the impl
2307 /// or trait. This is a bit weird but basically because right now we
2308 /// don't handle the general case, but instead map it to one of
2309 /// several pre-defined options using various heuristics, this method
2310 /// comes back to check after the fact that explicit type the user
2311 /// wrote actually matches what the pre-defined option said.
2312 fn check_method_self_type<'a, 'tcx, RS:RegionScope>(
2313 ccx: &CrateCtxt<'a, 'tcx>,
2315 method_type: Rc<ty::Method<'tcx>>,
2316 required_type: Ty<'tcx>,
2317 explicit_self: &hir::ExplicitSelf,
2318 body_id: ast::NodeId)
2321 if let hir::SelfExplicit(ref ast_type, _) = explicit_self.node {
2322 let typ = ccx.icx(&method_type.predicates).to_ty(rs, &**ast_type);
2323 let base_type = match typ.sty {
2324 ty::TyRef(_, tm) => tm.ty,
2325 ty::TyBox(typ) => typ,
2329 let body_scope = tcx.region_maps.item_extent(body_id);
2331 // "Required type" comes from the trait definition. It may
2332 // contain late-bound regions from the method, but not the
2333 // trait (since traits only have early-bound region
2335 assert!(!base_type.has_regions_escaping_depth(1));
2336 let required_type_free =
2337 liberate_early_bound_regions(
2339 &tcx.liberate_late_bound_regions(body_scope, &ty::Binder(required_type)));
2341 // The "base type" comes from the impl. It too may have late-bound
2342 // regions from the method.
2343 assert!(!base_type.has_regions_escaping_depth(1));
2344 let base_type_free =
2345 liberate_early_bound_regions(
2347 &tcx.liberate_late_bound_regions(body_scope, &ty::Binder(base_type)));
2349 debug!("required_type={:?} required_type_free={:?} \
2350 base_type={:?} base_type_free={:?}",
2356 let infcx = infer::new_infer_ctxt(tcx, &tcx.tables, None, false);
2357 drop(::require_same_types(tcx,
2364 format!("mismatched self type: expected `{}`",
2368 // We could conceviably add more free-region relations here,
2369 // but since this code is just concerned with checking that
2370 // the `&Self` types etc match up, it's not really necessary.
2371 // It would just allow people to be more approximate in some
2372 // cases. In any case, we can do it later as we feel the need;
2373 // I'd like this function to go away eventually.
2374 let free_regions = FreeRegionMap::new();
2376 infcx.resolve_regions_and_report_errors(&free_regions, body_id);
2379 fn liberate_early_bound_regions<'tcx,T>(
2380 tcx: &ty::ctxt<'tcx>,
2381 scope: region::CodeExtent,
2384 where T : TypeFoldable<'tcx>
2387 * Convert early-bound regions into free regions; normally this is done by
2388 * applying the `free_substs` from the `ParameterEnvironment`, but this particular
2389 * method-self-type check is kind of hacky and done very early in the process,
2390 * before we really have a `ParameterEnvironment` to check.
2393 tcx.fold_regions(value, &mut false, |region, _| {
2395 ty::ReEarlyBound(data) => {
2396 ty::ReFree(ty::FreeRegion {
2398 bound_region: ty::BrNamed(data.def_id, data.name)
2407 /// Checks that all the type parameters on an impl
2408 fn enforce_impl_params_are_constrained<'tcx>(tcx: &ty::ctxt<'tcx>,
2409 ast_generics: &hir::Generics,
2411 impl_items: &[P<hir::ImplItem>])
2413 let impl_scheme = tcx.lookup_item_type(impl_def_id);
2414 let impl_predicates = tcx.lookup_predicates(impl_def_id);
2415 let impl_trait_ref = tcx.impl_trait_ref(impl_def_id);
2417 // The trait reference is an input, so find all type parameters
2418 // reachable from there, to start (if this is an inherent impl,
2419 // then just examine the self type).
2420 let mut input_parameters: HashSet<_> =
2421 ctp::parameters_for_type(impl_scheme.ty).into_iter().collect();
2422 if let Some(ref trait_ref) = impl_trait_ref {
2423 input_parameters.extend(ctp::parameters_for_trait_ref(trait_ref));
2426 ctp::identify_constrained_type_params(tcx,
2427 impl_predicates.predicates.as_slice(),
2429 &mut input_parameters);
2431 for (index, ty_param) in ast_generics.ty_params.iter().enumerate() {
2432 let param_ty = ty::ParamTy { space: TypeSpace,
2434 name: ty_param.name };
2435 if !input_parameters.contains(&ctp::Parameter::Type(param_ty)) {
2436 report_unused_parameter(tcx, ty_param.span, "type", ¶m_ty.to_string());
2440 // Every lifetime used in an associated type must be constrained.
2442 let lifetimes_in_associated_types: HashSet<_> =
2444 .map(|item| tcx.impl_or_trait_item(tcx.map.local_def_id(item.id)))
2445 .filter_map(|item| match item {
2446 ty::TypeTraitItem(ref assoc_ty) => assoc_ty.ty,
2447 ty::ConstTraitItem(..) | ty::MethodTraitItem(..) => None
2449 .flat_map(|ty| ctp::parameters_for_type(ty))
2450 .filter_map(|p| match p {
2451 ctp::Parameter::Type(_) => None,
2452 ctp::Parameter::Region(r) => Some(r),
2456 for (index, lifetime_def) in ast_generics.lifetimes.iter().enumerate() {
2457 let def_id = tcx.map.local_def_id(lifetime_def.lifetime.id);
2458 let region = ty::EarlyBoundRegion { def_id: def_id,
2460 index: index as u32,
2461 name: lifetime_def.lifetime.name };
2463 lifetimes_in_associated_types.contains(®ion) && // (*)
2464 !input_parameters.contains(&ctp::Parameter::Region(region))
2466 report_unused_parameter(tcx, lifetime_def.lifetime.span,
2467 "lifetime", ®ion.name.to_string());
2471 // (*) This is a horrible concession to reality. I think it'd be
2472 // better to just ban unconstrianed lifetimes outright, but in
2473 // practice people do non-hygenic macros like:
2476 // macro_rules! __impl_slice_eq1 {
2477 // ($Lhs: ty, $Rhs: ty, $Bound: ident) => {
2478 // impl<'a, 'b, A: $Bound, B> PartialEq<$Rhs> for $Lhs where A: PartialEq<B> {
2485 // In a concession to backwards compatbility, we continue to
2486 // permit those, so long as the lifetimes aren't used in
2487 // associated types. I believe this is sound, because lifetimes
2488 // used elsewhere are not projected back out.
2491 fn report_unused_parameter(tcx: &ty::ctxt,
2496 span_err!(tcx.sess, span, E0207,
2497 "the {} parameter `{}` is not constrained by the \
2498 impl trait, self type, or predicates",