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 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().zip(variant.fields.iter()) {
1014 convert_field(ccx, &scheme.generics, &predicates, f, ty_f)
1017 if !struct_def.is_struct() {
1018 convert_variant_ctor(tcx, struct_def.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::Struct => 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>]) {
1068 // fill the field types
1069 for (variant, ty_variant) in variants.iter().zip(def.variants.iter()) {
1070 for (f, ty_f) in variant.node.data.fields().zip(ty_variant.fields.iter()) {
1071 convert_field(ccx, &scheme.generics, &predicates, f, ty_f)
1074 // Convert the ctor, if any. This also registers the variant as
1076 convert_variant_ctor(
1078 variant.node.data.id,
1086 fn convert_struct_variant<'tcx>(tcx: &ty::ctxt<'tcx>,
1090 def: &hir::VariantData) -> ty::VariantDefData<'tcx, 'tcx> {
1091 let mut seen_fields: FnvHashMap<ast::Name, Span> = FnvHashMap();
1092 let fields = def.fields().map(|f| {
1093 let fid = tcx.map.local_def_id(f.node.id);
1095 hir::NamedField(name, vis) => {
1096 let dup_span = seen_fields.get(&name).cloned();
1097 if let Some(prev_span) = dup_span {
1098 span_err!(tcx.sess, f.span, E0124,
1099 "field `{}` is already declared",
1101 span_note!(tcx.sess, prev_span, "previously declared here");
1103 seen_fields.insert(name, f.span);
1106 ty::FieldDefData::new(fid, name, vis)
1108 hir::UnnamedField(vis) => {
1109 ty::FieldDefData::new(fid, special_idents::unnamed_field.name, vis)
1113 ty::VariantDefData {
1121 fn convert_struct_def<'tcx>(tcx: &ty::ctxt<'tcx>,
1123 def: &hir::VariantData)
1124 -> ty::AdtDefMaster<'tcx>
1127 let did = tcx.map.local_def_id(it.id);
1128 let ctor_id = if !def.is_struct() {
1129 tcx.map.local_def_id(def.id)
1135 ty::AdtKind::Struct,
1136 vec![convert_struct_variant(tcx, ctor_id, it.name, 0, def)]
1140 fn convert_enum_def<'tcx>(tcx: &ty::ctxt<'tcx>,
1143 -> ty::AdtDefMaster<'tcx>
1145 fn evaluate_disr_expr<'tcx>(tcx: &ty::ctxt<'tcx>,
1147 e: &hir::Expr) -> Option<ty::Disr> {
1148 debug!("disr expr, checking {}", pprust::expr_to_string(e));
1150 let hint = UncheckedExprHint(repr_ty);
1151 match const_eval::eval_const_expr_partial(tcx, e, hint) {
1152 Ok(ConstVal::Int(val)) => Some(val as ty::Disr),
1153 Ok(ConstVal::Uint(val)) => Some(val as ty::Disr),
1155 let sign_desc = if repr_ty.is_signed() {
1160 span_err!(tcx.sess, e.span, E0079,
1161 "expected {} integer constant",
1166 span_err!(tcx.sess, err.span, E0080,
1167 "constant evaluation error: {}",
1169 if !e.span.contains(err.span) {
1170 tcx.sess.span_note(e.span, "for enum discriminant here");
1177 fn report_discrim_overflow(tcx: &ty::ctxt,
1180 repr_type: attr::IntType,
1181 prev_val: ty::Disr) {
1182 let computed_value = repr_type.disr_wrap_incr(Some(prev_val));
1183 let computed_value = repr_type.disr_string(computed_value);
1184 let prev_val = repr_type.disr_string(prev_val);
1185 let repr_type = repr_type.to_ty(tcx);
1186 span_err!(tcx.sess, variant_span, E0370,
1187 "enum discriminant overflowed on value after {}: {}; \
1188 set explicitly via {} = {} if that is desired outcome",
1189 prev_val, repr_type, variant_name, computed_value);
1192 fn next_disr(tcx: &ty::ctxt,
1194 repr_type: attr::IntType,
1195 prev_disr_val: Option<ty::Disr>) -> Option<ty::Disr> {
1196 if let Some(prev_disr_val) = prev_disr_val {
1197 let result = repr_type.disr_incr(prev_disr_val);
1198 if let None = result {
1199 report_discrim_overflow(tcx, v.span, &v.node.name.as_str(),
1200 repr_type, prev_disr_val);
1204 Some(ty::INITIAL_DISCRIMINANT_VALUE)
1207 fn convert_enum_variant<'tcx>(tcx: &ty::ctxt<'tcx>,
1210 -> ty::VariantDefData<'tcx, 'tcx>
1212 let did = tcx.map.local_def_id(v.node.data.id);
1213 let name = v.node.name;
1214 convert_struct_variant(tcx, did, name, disr, &v.node.data)
1216 let did = tcx.map.local_def_id(it.id);
1217 let repr_hints = tcx.lookup_repr_hints(did);
1218 let (repr_type, repr_type_ty) = tcx.enum_repr_type(repr_hints.get(0));
1219 let mut prev_disr = None;
1220 let variants = def.variants.iter().map(|v| {
1221 let disr = match v.node.disr_expr {
1222 Some(ref e) => evaluate_disr_expr(tcx, repr_type_ty, e),
1223 None => next_disr(tcx, v, repr_type, prev_disr)
1224 }.unwrap_or(repr_type.disr_wrap_incr(prev_disr));
1226 let v = convert_enum_variant(tcx, v, disr);
1227 prev_disr = Some(disr);
1230 tcx.intern_adt_def(tcx.map.local_def_id(it.id), ty::AdtKind::Enum, variants)
1233 /// Ensures that the super-predicates of the trait with def-id
1234 /// trait_def_id are converted and stored. This does NOT ensure that
1235 /// the transitive super-predicates are converted; that is the job of
1236 /// the `ensure_super_predicates()` method in the `AstConv` impl
1237 /// above. Returns a list of trait def-ids that must be ensured as
1238 /// well to guarantee that the transitive superpredicates are
1240 fn ensure_super_predicates_step(ccx: &CrateCtxt,
1241 trait_def_id: DefId)
1246 debug!("ensure_super_predicates_step(trait_def_id={:?})", trait_def_id);
1248 let trait_node_id = if let Some(n) = tcx.map.as_local_node_id(trait_def_id) {
1251 // If this trait comes from an external crate, then all of the
1252 // supertraits it may depend on also must come from external
1253 // crates, and hence all of them already have their
1254 // super-predicates "converted" (and available from crate
1255 // meta-data), so there is no need to transitively test them.
1259 let superpredicates = tcx.super_predicates.borrow().get(&trait_def_id).cloned();
1260 let superpredicates = superpredicates.unwrap_or_else(|| {
1261 let item = match ccx.tcx.map.get(trait_node_id) {
1262 hir_map::NodeItem(item) => item,
1263 _ => ccx.tcx.sess.bug(&format!("trait_node_id {} is not an item", trait_node_id))
1266 let (generics, bounds) = match item.node {
1267 hir::ItemTrait(_, ref generics, ref supertraits, _) => (generics, supertraits),
1268 _ => tcx.sess.span_bug(item.span,
1269 "ensure_super_predicates_step invoked on non-trait"),
1272 // In-scope when converting the superbounds for `Trait` are
1273 // that `Self:Trait` as well as any bounds that appear on the
1275 let trait_def = trait_def_of_item(ccx, item);
1276 let self_predicate = ty::GenericPredicates {
1277 predicates: VecPerParamSpace::new(vec![],
1278 vec![trait_def.trait_ref.to_predicate()],
1281 let scope = &(generics, &self_predicate);
1283 // Convert the bounds that follow the colon, e.g. `Bar+Zed` in `trait Foo : Bar+Zed`.
1284 let self_param_ty = tcx.mk_self_type();
1285 let superbounds1 = compute_bounds(&ccx.icx(scope),
1291 let superbounds1 = superbounds1.predicates(tcx, self_param_ty);
1293 // Convert any explicit superbounds in the where clause,
1294 // e.g. `trait Foo where Self : Bar`:
1295 let superbounds2 = generics.get_type_parameter_bounds(&ccx.icx(scope), item.span, item.id);
1297 // Combine the two lists to form the complete set of superbounds:
1298 let superbounds = superbounds1.into_iter().chain(superbounds2).collect();
1299 let superpredicates = ty::GenericPredicates {
1300 predicates: VecPerParamSpace::new(superbounds, vec![], vec![])
1302 debug!("superpredicates for trait {:?} = {:?}",
1303 tcx.map.local_def_id(item.id),
1306 tcx.super_predicates.borrow_mut().insert(trait_def_id, superpredicates.clone());
1311 let def_ids: Vec<_> = superpredicates.predicates
1313 .filter_map(|p| p.to_opt_poly_trait_ref())
1314 .map(|tr| tr.def_id())
1317 debug!("ensure_super_predicates_step: def_ids={:?}", def_ids);
1322 fn trait_def_of_item<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
1324 -> &'tcx ty::TraitDef<'tcx>
1326 let def_id = ccx.tcx.map.local_def_id(it.id);
1329 if let Some(def) = tcx.trait_defs.borrow().get(&def_id) {
1333 let (unsafety, generics, items) = match it.node {
1334 hir::ItemTrait(unsafety, ref generics, _, ref items) => (unsafety, generics, items),
1335 _ => tcx.sess.span_bug(it.span, "trait_def_of_item invoked on non-trait"),
1338 let paren_sugar = tcx.has_attr(def_id, "rustc_paren_sugar");
1339 if paren_sugar && !ccx.tcx.sess.features.borrow().unboxed_closures {
1340 ccx.tcx.sess.span_err(
1342 "the `#[rustc_paren_sugar]` attribute is a temporary means of controlling \
1343 which traits can use parenthetical notation");
1344 fileline_help!(ccx.tcx.sess, it.span,
1345 "add `#![feature(unboxed_closures)]` to \
1346 the crate attributes to use it");
1349 let substs = ccx.tcx.mk_substs(mk_trait_substs(ccx, generics));
1351 let ty_generics = ty_generics_for_trait(ccx, it.id, substs, generics);
1353 let associated_type_names: Vec<_> = items.iter().filter_map(|trait_item| {
1354 match trait_item.node {
1355 hir::TypeTraitItem(..) => Some(trait_item.name),
1360 let trait_ref = ty::TraitRef {
1365 let trait_def = ty::TraitDef {
1366 paren_sugar: paren_sugar,
1368 generics: ty_generics,
1369 trait_ref: trait_ref,
1370 associated_type_names: associated_type_names,
1371 nonblanket_impls: RefCell::new(FnvHashMap()),
1372 blanket_impls: RefCell::new(vec![]),
1373 flags: Cell::new(ty::TraitFlags::NO_TRAIT_FLAGS)
1376 return tcx.intern_trait_def(trait_def);
1378 fn mk_trait_substs<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
1379 generics: &hir::Generics)
1384 // Creates a no-op substitution for the trait's type parameters.
1389 .map(|(i, def)| ty::ReEarlyBound(ty::EarlyBoundRegion {
1390 def_id: tcx.map.local_def_id(def.lifetime.id),
1393 name: def.lifetime.name
1397 // Start with the generics in the type parameters...
1402 .map(|(i, def)| tcx.mk_param(TypeSpace,
1403 i as u32, def.name))
1406 // ...and also create the `Self` parameter.
1407 let self_ty = tcx.mk_self_type();
1409 Substs::new_trait(types, regions, self_ty)
1413 fn trait_defines_associated_type_named(ccx: &CrateCtxt,
1414 trait_node_id: ast::NodeId,
1415 assoc_name: ast::Name)
1418 let item = match ccx.tcx.map.get(trait_node_id) {
1419 hir_map::NodeItem(item) => item,
1420 _ => ccx.tcx.sess.bug(&format!("trait_node_id {} is not an item", trait_node_id))
1423 let trait_items = match item.node {
1424 hir::ItemTrait(_, _, _, ref trait_items) => trait_items,
1425 _ => ccx.tcx.sess.bug(&format!("trait_node_id {} is not a trait", trait_node_id))
1428 trait_items.iter().any(|trait_item| {
1429 match trait_item.node {
1430 hir::TypeTraitItem(..) => trait_item.name == assoc_name,
1436 fn convert_trait_predicates<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>, it: &hir::Item) {
1438 let trait_def = trait_def_of_item(ccx, it);
1440 let def_id = ccx.tcx.map.local_def_id(it.id);
1442 let (generics, items) = match it.node {
1443 hir::ItemTrait(_, ref generics, _, ref items) => (generics, items),
1447 &format!("trait_def_of_item invoked on {:?}", s));
1451 let super_predicates = ccx.tcx.lookup_super_predicates(def_id);
1453 // `ty_generic_predicates` below will consider the bounds on the type
1454 // parameters (including `Self`) and the explicit where-clauses,
1455 // but to get the full set of predicates on a trait we need to add
1456 // in the supertrait bounds and anything declared on the
1457 // associated types.
1458 let mut base_predicates = super_predicates;
1460 // Add in a predicate that `Self:Trait` (where `Trait` is the
1461 // current trait). This is needed for builtin bounds.
1462 let self_predicate = trait_def.trait_ref.to_poly_trait_ref().to_predicate();
1463 base_predicates.predicates.push(SelfSpace, self_predicate);
1465 // add in the explicit where-clauses
1466 let mut trait_predicates =
1467 ty_generic_predicates(ccx, TypeSpace, generics, &base_predicates);
1469 let assoc_predicates = predicates_for_associated_types(ccx,
1472 trait_def.trait_ref,
1474 trait_predicates.predicates.extend(TypeSpace, assoc_predicates.into_iter());
1476 let prev_predicates = tcx.predicates.borrow_mut().insert(def_id, trait_predicates);
1477 assert!(prev_predicates.is_none());
1481 fn predicates_for_associated_types<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
1482 ast_generics: &hir::Generics,
1483 trait_predicates: &ty::GenericPredicates<'tcx>,
1484 self_trait_ref: ty::TraitRef<'tcx>,
1485 trait_items: &[P<hir::TraitItem>])
1486 -> Vec<ty::Predicate<'tcx>>
1488 trait_items.iter().flat_map(|trait_item| {
1489 let bounds = match trait_item.node {
1490 hir::TypeTraitItem(ref bounds, _) => bounds,
1492 return vec!().into_iter();
1496 let assoc_ty = ccx.tcx.mk_projection(self_trait_ref,
1499 let bounds = compute_bounds(&ccx.icx(&(ast_generics, trait_predicates)),
1502 SizedByDefault::Yes,
1505 bounds.predicates(ccx.tcx, assoc_ty).into_iter()
1510 fn type_scheme_of_def_id<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
1512 -> ty::TypeScheme<'tcx>
1514 if let Some(node_id) = ccx.tcx.map.as_local_node_id(def_id) {
1515 match ccx.tcx.map.find(node_id) {
1516 Some(hir_map::NodeItem(item)) => {
1517 type_scheme_of_item(ccx, &*item)
1519 Some(hir_map::NodeForeignItem(foreign_item)) => {
1520 let abi = ccx.tcx.map.get_foreign_abi(node_id);
1521 type_scheme_of_foreign_item(ccx, &*foreign_item, abi)
1524 ccx.tcx.sess.bug(&format!("unexpected sort of node \
1525 in get_item_type_scheme(): {:?}",
1530 ccx.tcx.lookup_item_type(def_id)
1534 fn type_scheme_of_item<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
1536 -> ty::TypeScheme<'tcx>
1538 memoized(&ccx.tcx.tcache,
1539 ccx.tcx.map.local_def_id(it.id),
1540 |_| compute_type_scheme_of_item(ccx, it))
1543 fn compute_type_scheme_of_item<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
1545 -> ty::TypeScheme<'tcx>
1549 hir::ItemStatic(ref t, _, _) | hir::ItemConst(ref t, _) => {
1550 let ty = ccx.icx(&()).to_ty(&ExplicitRscope, &**t);
1551 ty::TypeScheme { ty: ty, generics: ty::Generics::empty() }
1553 hir::ItemFn(ref decl, unsafety, _, abi, ref generics, _) => {
1554 let ty_generics = ty_generics_for_fn(ccx, generics, &ty::Generics::empty());
1555 let tofd = astconv::ty_of_bare_fn(&ccx.icx(generics), unsafety, abi, &**decl);
1556 let ty = tcx.mk_fn(Some(ccx.tcx.map.local_def_id(it.id)), tcx.mk_bare_fn(tofd));
1557 ty::TypeScheme { ty: ty, generics: ty_generics }
1559 hir::ItemTy(ref t, ref generics) => {
1560 let ty_generics = ty_generics_for_type_or_impl(ccx, generics);
1561 let ty = ccx.icx(generics).to_ty(&ExplicitRscope, &**t);
1562 ty::TypeScheme { ty: ty, generics: ty_generics }
1564 hir::ItemEnum(ref ei, ref generics) => {
1565 let ty_generics = ty_generics_for_type_or_impl(ccx, generics);
1566 let substs = mk_item_substs(ccx, &ty_generics);
1567 let def = convert_enum_def(tcx, it, ei);
1568 let t = tcx.mk_enum(def, tcx.mk_substs(substs));
1569 ty::TypeScheme { ty: t, generics: ty_generics }
1571 hir::ItemStruct(ref si, ref generics) => {
1572 let ty_generics = ty_generics_for_type_or_impl(ccx, generics);
1573 let substs = mk_item_substs(ccx, &ty_generics);
1574 let def = convert_struct_def(tcx, it, si);
1575 let t = tcx.mk_struct(def, tcx.mk_substs(substs));
1576 ty::TypeScheme { ty: t, generics: ty_generics }
1578 hir::ItemDefaultImpl(..) |
1579 hir::ItemTrait(..) |
1582 hir::ItemForeignMod(..) |
1583 hir::ItemExternCrate(..) |
1584 hir::ItemUse(..) => {
1587 &format!("compute_type_scheme_of_item: unexpected item type: {:?}",
1593 fn convert_typed_item<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
1595 -> (ty::TypeScheme<'tcx>, ty::GenericPredicates<'tcx>)
1599 let tag = type_scheme_of_item(ccx, it);
1600 let scheme = TypeScheme { generics: tag.generics, ty: tag.ty };
1601 let predicates = match it.node {
1602 hir::ItemStatic(..) | hir::ItemConst(..) => {
1603 ty::GenericPredicates::empty()
1605 hir::ItemFn(_, _, _, _, ref ast_generics, _) => {
1606 ty_generic_predicates_for_fn(ccx, ast_generics, &ty::GenericPredicates::empty())
1608 hir::ItemTy(_, ref generics) => {
1609 ty_generic_predicates_for_type_or_impl(ccx, generics)
1611 hir::ItemEnum(_, ref generics) => {
1612 ty_generic_predicates_for_type_or_impl(ccx, generics)
1614 hir::ItemStruct(_, ref generics) => {
1615 ty_generic_predicates_for_type_or_impl(ccx, generics)
1617 hir::ItemDefaultImpl(..) |
1618 hir::ItemTrait(..) |
1619 hir::ItemExternCrate(..) |
1623 hir::ItemForeignMod(..) => {
1626 &format!("compute_type_scheme_of_item: unexpected item type: {:?}",
1631 let prev_predicates = tcx.predicates.borrow_mut().insert(ccx.tcx.map.local_def_id(it.id),
1632 predicates.clone());
1633 assert!(prev_predicates.is_none());
1636 if tcx.has_attr(ccx.tcx.map.local_def_id(it.id), "rustc_object_lifetime_default") {
1637 let object_lifetime_default_reprs: String =
1638 scheme.generics.types.iter()
1639 .map(|t| match t.object_lifetime_default {
1640 ty::ObjectLifetimeDefault::Specific(r) => r.to_string(),
1641 d => format!("{:?}", d),
1643 .collect::<Vec<String>>()
1646 tcx.sess.span_err(it.span, &object_lifetime_default_reprs);
1649 return (scheme, predicates);
1652 fn type_scheme_of_foreign_item<'a, 'tcx>(
1653 ccx: &CrateCtxt<'a, 'tcx>,
1654 it: &hir::ForeignItem,
1656 -> ty::TypeScheme<'tcx>
1658 memoized(&ccx.tcx.tcache,
1659 ccx.tcx.map.local_def_id(it.id),
1660 |_| compute_type_scheme_of_foreign_item(ccx, it, abi))
1663 fn compute_type_scheme_of_foreign_item<'a, 'tcx>(
1664 ccx: &CrateCtxt<'a, 'tcx>,
1665 it: &hir::ForeignItem,
1667 -> ty::TypeScheme<'tcx>
1670 hir::ForeignItemFn(ref fn_decl, ref generics) => {
1671 compute_type_scheme_of_foreign_fn_decl(ccx, fn_decl, generics, abi)
1673 hir::ForeignItemStatic(ref t, _) => {
1675 generics: ty::Generics::empty(),
1676 ty: ast_ty_to_ty(&ccx.icx(&()), &ExplicitRscope, t)
1682 fn convert_foreign_item<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
1683 it: &hir::ForeignItem)
1685 // For reasons I cannot fully articulate, I do so hate the AST
1686 // map, and I regard each time that I use it as a personal and
1687 // moral failing, but at the moment it seems like the only
1688 // convenient way to extract the ABI. - ndm
1690 let abi = tcx.map.get_foreign_abi(it.id);
1692 let scheme = type_scheme_of_foreign_item(ccx, it, abi);
1693 write_ty_to_tcx(ccx.tcx, it.id, scheme.ty);
1695 let predicates = match it.node {
1696 hir::ForeignItemFn(_, ref generics) => {
1697 ty_generic_predicates_for_fn(ccx, generics, &ty::GenericPredicates::empty())
1699 hir::ForeignItemStatic(..) => {
1700 ty::GenericPredicates::empty()
1704 let prev_predicates = tcx.predicates.borrow_mut().insert(ccx.tcx.map.local_def_id(it.id),
1706 assert!(prev_predicates.is_none());
1709 fn ty_generics_for_type_or_impl<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
1710 generics: &hir::Generics)
1711 -> ty::Generics<'tcx> {
1712 ty_generics(ccx, TypeSpace, generics, &ty::Generics::empty())
1715 fn ty_generic_predicates_for_type_or_impl<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
1716 generics: &hir::Generics)
1717 -> ty::GenericPredicates<'tcx>
1719 ty_generic_predicates(ccx, TypeSpace, generics, &ty::GenericPredicates::empty())
1722 fn ty_generics_for_trait<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
1723 trait_id: ast::NodeId,
1724 substs: &'tcx Substs<'tcx>,
1725 ast_generics: &hir::Generics)
1726 -> ty::Generics<'tcx>
1728 debug!("ty_generics_for_trait(trait_id={:?}, substs={:?})",
1729 ccx.tcx.map.local_def_id(trait_id), substs);
1731 let mut generics = ty_generics_for_type_or_impl(ccx, ast_generics);
1733 // Add in the self type parameter.
1735 // Something of a hack: use the node id for the trait, also as
1736 // the node id for the Self type parameter.
1737 let param_id = trait_id;
1739 let parent = ccx.tcx.map.get_parent(param_id);
1741 let def = ty::TypeParameterDef {
1744 name: special_idents::type_self.name,
1745 def_id: ccx.tcx.map.local_def_id(param_id),
1746 default_def_id: ccx.tcx.map.local_def_id(parent),
1748 object_lifetime_default: ty::ObjectLifetimeDefault::BaseDefault,
1751 ccx.tcx.ty_param_defs.borrow_mut().insert(param_id, def.clone());
1753 generics.types.push(SelfSpace, def);
1758 fn ty_generics_for_fn<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
1759 generics: &hir::Generics,
1760 base_generics: &ty::Generics<'tcx>)
1761 -> ty::Generics<'tcx>
1763 ty_generics(ccx, FnSpace, generics, base_generics)
1766 fn ty_generic_predicates_for_fn<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
1767 generics: &hir::Generics,
1768 base_predicates: &ty::GenericPredicates<'tcx>)
1769 -> ty::GenericPredicates<'tcx>
1771 ty_generic_predicates(ccx, FnSpace, generics, base_predicates)
1774 // Add the Sized bound, unless the type parameter is marked as `?Sized`.
1775 fn add_unsized_bound<'tcx>(astconv: &AstConv<'tcx>,
1776 bounds: &mut ty::BuiltinBounds,
1777 ast_bounds: &[hir::TyParamBound],
1780 let tcx = astconv.tcx();
1782 // Try to find an unbound in bounds.
1783 let mut unbound = None;
1784 for ab in ast_bounds {
1785 if let &hir::TraitTyParamBound(ref ptr, hir::TraitBoundModifier::Maybe) = ab {
1786 if unbound.is_none() {
1787 assert!(ptr.bound_lifetimes.is_empty());
1788 unbound = Some(ptr.trait_ref.clone());
1790 span_err!(tcx.sess, span, E0203,
1791 "type parameter has more than one relaxed default \
1792 bound, only one is supported");
1797 let kind_id = tcx.lang_items.require(SizedTraitLangItem);
1800 // FIXME(#8559) currently requires the unbound to be built-in.
1801 let trait_def_id = tcx.trait_ref_to_def_id(tpb);
1803 Ok(kind_id) if trait_def_id != kind_id => {
1804 tcx.sess.span_warn(span,
1805 "default bound relaxed for a type parameter, but \
1806 this does nothing because the given bound is not \
1807 a default. Only `?Sized` is supported");
1808 tcx.try_add_builtin_trait(kind_id, bounds);
1813 _ if kind_id.is_ok() => {
1814 tcx.try_add_builtin_trait(kind_id.unwrap(), bounds);
1816 // No lang item for Sized, so we can't add it as a bound.
1821 /// Returns the early-bound lifetimes declared in this generics
1822 /// listing. For anything other than fns/methods, this is just all
1823 /// the lifetimes that are declared. For fns or methods, we have to
1824 /// screen out those that do not appear in any where-clauses etc using
1825 /// `resolve_lifetime::early_bound_lifetimes`.
1826 fn early_bound_lifetimes_from_generics(space: ParamSpace,
1827 ast_generics: &hir::Generics)
1828 -> Vec<hir::LifetimeDef>
1831 SelfSpace | TypeSpace => ast_generics.lifetimes.to_vec(),
1832 FnSpace => resolve_lifetime::early_bound_lifetimes(ast_generics),
1836 fn ty_generic_predicates<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
1838 ast_generics: &hir::Generics,
1839 base_predicates: &ty::GenericPredicates<'tcx>)
1840 -> ty::GenericPredicates<'tcx>
1843 let mut result = base_predicates.clone();
1845 // Collect the predicates that were written inline by the user on each
1846 // type parameter (e.g., `<T:Foo>`).
1847 for (index, param) in ast_generics.ty_params.iter().enumerate() {
1848 let index = index as u32;
1849 let param_ty = ty::ParamTy::new(space, index, param.name).to_ty(ccx.tcx);
1850 let bounds = compute_bounds(&ccx.icx(&(base_predicates, ast_generics)),
1853 SizedByDefault::Yes,
1855 let predicates = bounds.predicates(ccx.tcx, param_ty);
1856 result.predicates.extend(space, predicates.into_iter());
1859 // Collect the region predicates that were declared inline as
1860 // well. In the case of parameters declared on a fn or method, we
1861 // have to be careful to only iterate over early-bound regions.
1862 let early_lifetimes = early_bound_lifetimes_from_generics(space, ast_generics);
1863 for (index, param) in early_lifetimes.iter().enumerate() {
1864 let index = index as u32;
1865 let def_id = tcx.map.local_def_id(param.lifetime.id);
1867 ty::ReEarlyBound(ty::EarlyBoundRegion {
1871 name: param.lifetime.name
1873 for bound in ¶m.bounds {
1874 let bound_region = ast_region_to_region(ccx.tcx, bound);
1875 let outlives = ty::Binder(ty::OutlivesPredicate(region, bound_region));
1876 result.predicates.push(space, outlives.to_predicate());
1880 // Add in the bounds that appear in the where-clause
1881 let where_clause = &ast_generics.where_clause;
1882 for predicate in &where_clause.predicates {
1884 &hir::WherePredicate::BoundPredicate(ref bound_pred) => {
1885 let ty = ast_ty_to_ty(&ccx.icx(&(base_predicates, ast_generics)),
1887 &*bound_pred.bounded_ty);
1889 for bound in bound_pred.bounds.iter() {
1891 &hir::TyParamBound::TraitTyParamBound(ref poly_trait_ref, _) => {
1892 let mut projections = Vec::new();
1895 conv_poly_trait_ref(&ccx.icx(&(base_predicates, ast_generics)),
1900 result.predicates.push(space, trait_ref.to_predicate());
1902 for projection in &projections {
1903 result.predicates.push(space, projection.to_predicate());
1907 &hir::TyParamBound::RegionTyParamBound(ref lifetime) => {
1908 let region = ast_region_to_region(tcx, lifetime);
1909 let pred = ty::Binder(ty::OutlivesPredicate(ty, region));
1910 result.predicates.push(space, ty::Predicate::TypeOutlives(pred))
1916 &hir::WherePredicate::RegionPredicate(ref region_pred) => {
1917 let r1 = ast_region_to_region(tcx, ®ion_pred.lifetime);
1918 for bound in ®ion_pred.bounds {
1919 let r2 = ast_region_to_region(tcx, bound);
1920 let pred = ty::Binder(ty::OutlivesPredicate(r1, r2));
1921 result.predicates.push(space, ty::Predicate::RegionOutlives(pred))
1925 &hir::WherePredicate::EqPredicate(ref eq_pred) => {
1927 tcx.sess.span_bug(eq_pred.span,
1928 "Equality constraints are not yet \
1929 implemented (#20041)")
1937 fn ty_generics<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
1939 ast_generics: &hir::Generics,
1940 base_generics: &ty::Generics<'tcx>)
1941 -> ty::Generics<'tcx>
1944 let mut result = base_generics.clone();
1946 let early_lifetimes = early_bound_lifetimes_from_generics(space, ast_generics);
1947 for (i, l) in early_lifetimes.iter().enumerate() {
1948 let bounds = l.bounds.iter()
1949 .map(|l| ast_region_to_region(tcx, l))
1951 let def = ty::RegionParameterDef { name: l.lifetime.name,
1954 def_id: ccx.tcx.map.local_def_id(l.lifetime.id),
1956 result.regions.push(space, def);
1959 assert!(result.types.is_empty_in(space));
1961 // Now create the real type parameters.
1962 for i in 0..ast_generics.ty_params.len() {
1963 let def = get_or_create_type_parameter_def(ccx, ast_generics, space, i as u32);
1964 debug!("ty_generics: def for type param: {:?}, {:?}", def, space);
1965 result.types.push(space, def);
1971 fn convert_default_type_parameter<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
1977 let ty = ast_ty_to_ty(&ccx.icx(&()), &ExplicitRscope, &path);
1979 for leaf_ty in ty.walk() {
1980 if let ty::TyParam(p) = leaf_ty.sty {
1981 if p.space == space && p.idx >= index {
1982 span_err!(ccx.tcx.sess, path.span, E0128,
1983 "type parameters with a default cannot use \
1984 forward declared identifiers");
1986 return ccx.tcx.types.err
1994 fn get_or_create_type_parameter_def<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
1995 ast_generics: &hir::Generics,
1998 -> ty::TypeParameterDef<'tcx>
2000 let param = &ast_generics.ty_params[index as usize];
2003 match tcx.ty_param_defs.borrow().get(¶m.id) {
2004 Some(d) => { return d.clone(); }
2008 let default = param.default.as_ref().map(
2009 |def| convert_default_type_parameter(ccx, def, space, index)
2012 let object_lifetime_default =
2013 compute_object_lifetime_default(ccx, param.id,
2014 ¶m.bounds, &ast_generics.where_clause);
2016 let parent = tcx.map.get_parent(param.id);
2018 let def = ty::TypeParameterDef {
2022 def_id: ccx.tcx.map.local_def_id(param.id),
2023 default_def_id: ccx.tcx.map.local_def_id(parent),
2025 object_lifetime_default: object_lifetime_default,
2028 tcx.ty_param_defs.borrow_mut().insert(param.id, def.clone());
2033 /// Scan the bounds and where-clauses on a parameter to extract bounds
2034 /// of the form `T:'a` so as to determine the `ObjectLifetimeDefault`.
2035 /// This runs as part of computing the minimal type scheme, so we
2036 /// intentionally avoid just asking astconv to convert all the where
2037 /// clauses into a `ty::Predicate`. This is because that could induce
2038 /// artificial cycles.
2039 fn compute_object_lifetime_default<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
2040 param_id: ast::NodeId,
2041 param_bounds: &[hir::TyParamBound],
2042 where_clause: &hir::WhereClause)
2043 -> ty::ObjectLifetimeDefault
2045 let inline_bounds = from_bounds(ccx, param_bounds);
2046 let where_bounds = from_predicates(ccx, param_id, &where_clause.predicates);
2047 let all_bounds: HashSet<_> = inline_bounds.into_iter()
2048 .chain(where_bounds)
2050 return if all_bounds.len() > 1 {
2051 ty::ObjectLifetimeDefault::Ambiguous
2052 } else if all_bounds.len() == 0 {
2053 ty::ObjectLifetimeDefault::BaseDefault
2055 ty::ObjectLifetimeDefault::Specific(
2056 all_bounds.into_iter().next().unwrap())
2059 fn from_bounds<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
2060 bounds: &[hir::TyParamBound])
2064 .filter_map(|bound| {
2066 hir::TraitTyParamBound(..) =>
2068 hir::RegionTyParamBound(ref lifetime) =>
2069 Some(astconv::ast_region_to_region(ccx.tcx, lifetime)),
2075 fn from_predicates<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
2076 param_id: ast::NodeId,
2077 predicates: &[hir::WherePredicate])
2081 .flat_map(|predicate| {
2083 hir::WherePredicate::BoundPredicate(ref data) => {
2084 if data.bound_lifetimes.is_empty() &&
2085 is_param(ccx.tcx, &data.bounded_ty, param_id)
2087 from_bounds(ccx, &data.bounds).into_iter()
2089 Vec::new().into_iter()
2092 hir::WherePredicate::RegionPredicate(..) |
2093 hir::WherePredicate::EqPredicate(..) => {
2094 Vec::new().into_iter()
2102 enum SizedByDefault { Yes, No, }
2104 /// Translate the AST's notion of ty param bounds (which are an enum consisting of a newtyped Ty or
2105 /// a region) to ty's notion of ty param bounds, which can either be user-defined traits, or the
2106 /// built-in trait (formerly known as kind): Send.
2107 fn compute_bounds<'tcx>(astconv: &AstConv<'tcx>,
2108 param_ty: ty::Ty<'tcx>,
2109 ast_bounds: &[hir::TyParamBound],
2110 sized_by_default: SizedByDefault,
2112 -> astconv::Bounds<'tcx>
2115 conv_param_bounds(astconv,
2120 if let SizedByDefault::Yes = sized_by_default {
2121 add_unsized_bound(astconv,
2122 &mut bounds.builtin_bounds,
2127 bounds.trait_bounds.sort_by(|a,b| a.def_id().cmp(&b.def_id()));
2132 /// Converts a specific TyParamBound from the AST into a set of
2133 /// predicates that apply to the self-type. A vector is returned
2134 /// because this can be anywhere from 0 predicates (`T:?Sized` adds no
2135 /// predicates) to 1 (`T:Foo`) to many (`T:Bar<X=i32>` adds `T:Bar`
2136 /// and `<T as Bar>::X == i32`).
2137 fn predicates_from_bound<'tcx>(astconv: &AstConv<'tcx>,
2139 bound: &hir::TyParamBound)
2140 -> Vec<ty::Predicate<'tcx>>
2143 hir::TraitTyParamBound(ref tr, hir::TraitBoundModifier::None) => {
2144 let mut projections = Vec::new();
2145 let pred = conv_poly_trait_ref(astconv, param_ty, tr, &mut projections);
2146 projections.into_iter()
2147 .map(|p| p.to_predicate())
2148 .chain(Some(pred.to_predicate()))
2151 hir::RegionTyParamBound(ref lifetime) => {
2152 let region = ast_region_to_region(astconv.tcx(), lifetime);
2153 let pred = ty::Binder(ty::OutlivesPredicate(param_ty, region));
2154 vec![ty::Predicate::TypeOutlives(pred)]
2156 hir::TraitTyParamBound(_, hir::TraitBoundModifier::Maybe) => {
2162 fn conv_poly_trait_ref<'tcx>(astconv: &AstConv<'tcx>,
2164 trait_ref: &hir::PolyTraitRef,
2165 projections: &mut Vec<ty::PolyProjectionPredicate<'tcx>>)
2166 -> ty::PolyTraitRef<'tcx>
2168 astconv::instantiate_poly_trait_ref(astconv,
2175 fn conv_param_bounds<'a,'tcx>(astconv: &AstConv<'tcx>,
2177 param_ty: ty::Ty<'tcx>,
2178 ast_bounds: &[hir::TyParamBound])
2179 -> astconv::Bounds<'tcx>
2181 let tcx = astconv.tcx();
2182 let astconv::PartitionedBounds {
2186 } = astconv::partition_bounds(tcx, span, &ast_bounds);
2188 let mut projection_bounds = Vec::new();
2190 let trait_bounds: Vec<ty::PolyTraitRef> =
2192 .map(|bound| conv_poly_trait_ref(astconv,
2195 &mut projection_bounds))
2198 let region_bounds: Vec<ty::Region> =
2199 region_bounds.into_iter()
2200 .map(|r| ast_region_to_region(tcx, r))
2204 region_bounds: region_bounds,
2205 builtin_bounds: builtin_bounds,
2206 trait_bounds: trait_bounds,
2207 projection_bounds: projection_bounds,
2211 fn compute_type_scheme_of_foreign_fn_decl<'a, 'tcx>(
2212 ccx: &CrateCtxt<'a, 'tcx>,
2214 ast_generics: &hir::Generics,
2216 -> ty::TypeScheme<'tcx>
2218 for i in &decl.inputs {
2219 match (*i).pat.node {
2220 hir::PatIdent(_, _, _) => (),
2221 hir::PatWild(hir::PatWildSingle) => (),
2223 span_err!(ccx.tcx.sess, (*i).pat.span, E0130,
2224 "patterns aren't allowed in foreign function declarations");
2229 let ty_generics = ty_generics_for_fn(ccx, ast_generics, &ty::Generics::empty());
2231 let rb = BindingRscope::new();
2232 let input_tys = decl.inputs
2234 .map(|a| ty_of_arg(&ccx.icx(ast_generics), &rb, a, None))
2237 let output = match decl.output {
2238 hir::Return(ref ty) =>
2239 ty::FnConverging(ast_ty_to_ty(&ccx.icx(ast_generics), &rb, &**ty)),
2240 hir::DefaultReturn(..) =>
2241 ty::FnConverging(ccx.tcx.mk_nil()),
2242 hir::NoReturn(..) =>
2246 let t_fn = ccx.tcx.mk_fn(None,
2247 ccx.tcx.mk_bare_fn(ty::BareFnTy {
2249 unsafety: hir::Unsafety::Unsafe,
2250 sig: ty::Binder(ty::FnSig {inputs: input_tys,
2252 variadic: decl.variadic}),
2256 generics: ty_generics,
2261 fn mk_item_substs<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
2262 ty_generics: &ty::Generics<'tcx>)
2266 ty_generics.types.map(
2267 |def| ccx.tcx.mk_param_from_def(def));
2270 ty_generics.regions.map(
2271 |def| def.to_early_bound_region());
2273 Substs::new(types, regions)
2276 /// Verifies that the explicit self type of a method matches the impl
2277 /// or trait. This is a bit weird but basically because right now we
2278 /// don't handle the general case, but instead map it to one of
2279 /// several pre-defined options using various heuristics, this method
2280 /// comes back to check after the fact that explicit type the user
2281 /// wrote actually matches what the pre-defined option said.
2282 fn check_method_self_type<'a, 'tcx, RS:RegionScope>(
2283 ccx: &CrateCtxt<'a, 'tcx>,
2285 method_type: Rc<ty::Method<'tcx>>,
2286 required_type: Ty<'tcx>,
2287 explicit_self: &hir::ExplicitSelf,
2288 body_id: ast::NodeId)
2291 if let hir::SelfExplicit(ref ast_type, _) = explicit_self.node {
2292 let typ = ccx.icx(&method_type.predicates).to_ty(rs, &**ast_type);
2293 let base_type = match typ.sty {
2294 ty::TyRef(_, tm) => tm.ty,
2295 ty::TyBox(typ) => typ,
2299 let body_scope = tcx.region_maps.item_extent(body_id);
2301 // "Required type" comes from the trait definition. It may
2302 // contain late-bound regions from the method, but not the
2303 // trait (since traits only have early-bound region
2305 assert!(!base_type.has_regions_escaping_depth(1));
2306 let required_type_free =
2307 liberate_early_bound_regions(
2309 &tcx.liberate_late_bound_regions(body_scope, &ty::Binder(required_type)));
2311 // The "base type" comes from the impl. It too may have late-bound
2312 // regions from the method.
2313 assert!(!base_type.has_regions_escaping_depth(1));
2314 let base_type_free =
2315 liberate_early_bound_regions(
2317 &tcx.liberate_late_bound_regions(body_scope, &ty::Binder(base_type)));
2319 debug!("required_type={:?} required_type_free={:?} \
2320 base_type={:?} base_type_free={:?}",
2326 let infcx = infer::new_infer_ctxt(tcx, &tcx.tables, None, false);
2327 drop(::require_same_types(tcx,
2334 format!("mismatched self type: expected `{}`",
2338 // We could conceviably add more free-region relations here,
2339 // but since this code is just concerned with checking that
2340 // the `&Self` types etc match up, it's not really necessary.
2341 // It would just allow people to be more approximate in some
2342 // cases. In any case, we can do it later as we feel the need;
2343 // I'd like this function to go away eventually.
2344 let free_regions = FreeRegionMap::new();
2346 infcx.resolve_regions_and_report_errors(&free_regions, body_id);
2349 fn liberate_early_bound_regions<'tcx,T>(
2350 tcx: &ty::ctxt<'tcx>,
2351 scope: region::CodeExtent,
2354 where T : TypeFoldable<'tcx>
2357 * Convert early-bound regions into free regions; normally this is done by
2358 * applying the `free_substs` from the `ParameterEnvironment`, but this particular
2359 * method-self-type check is kind of hacky and done very early in the process,
2360 * before we really have a `ParameterEnvironment` to check.
2363 tcx.fold_regions(value, &mut false, |region, _| {
2365 ty::ReEarlyBound(data) => {
2366 ty::ReFree(ty::FreeRegion {
2368 bound_region: ty::BrNamed(data.def_id, data.name)
2377 /// Checks that all the type parameters on an impl
2378 fn enforce_impl_params_are_constrained<'tcx>(tcx: &ty::ctxt<'tcx>,
2379 ast_generics: &hir::Generics,
2381 impl_items: &[P<hir::ImplItem>])
2383 let impl_scheme = tcx.lookup_item_type(impl_def_id);
2384 let impl_predicates = tcx.lookup_predicates(impl_def_id);
2385 let impl_trait_ref = tcx.impl_trait_ref(impl_def_id);
2387 // The trait reference is an input, so find all type parameters
2388 // reachable from there, to start (if this is an inherent impl,
2389 // then just examine the self type).
2390 let mut input_parameters: HashSet<_> =
2391 ctp::parameters_for_type(impl_scheme.ty).into_iter().collect();
2392 if let Some(ref trait_ref) = impl_trait_ref {
2393 input_parameters.extend(ctp::parameters_for_trait_ref(trait_ref));
2396 ctp::identify_constrained_type_params(tcx,
2397 impl_predicates.predicates.as_slice(),
2399 &mut input_parameters);
2401 for (index, ty_param) in ast_generics.ty_params.iter().enumerate() {
2402 let param_ty = ty::ParamTy { space: TypeSpace,
2404 name: ty_param.name };
2405 if !input_parameters.contains(&ctp::Parameter::Type(param_ty)) {
2406 report_unused_parameter(tcx, ty_param.span, "type", ¶m_ty.to_string());
2410 // Every lifetime used in an associated type must be constrained.
2412 let lifetimes_in_associated_types: HashSet<_> =
2414 .map(|item| tcx.impl_or_trait_item(tcx.map.local_def_id(item.id)))
2415 .filter_map(|item| match item {
2416 ty::TypeTraitItem(ref assoc_ty) => assoc_ty.ty,
2417 ty::ConstTraitItem(..) | ty::MethodTraitItem(..) => None
2419 .flat_map(|ty| ctp::parameters_for_type(ty))
2420 .filter_map(|p| match p {
2421 ctp::Parameter::Type(_) => None,
2422 ctp::Parameter::Region(r) => Some(r),
2426 for (index, lifetime_def) in ast_generics.lifetimes.iter().enumerate() {
2427 let def_id = tcx.map.local_def_id(lifetime_def.lifetime.id);
2428 let region = ty::EarlyBoundRegion { def_id: def_id,
2430 index: index as u32,
2431 name: lifetime_def.lifetime.name };
2433 lifetimes_in_associated_types.contains(®ion) && // (*)
2434 !input_parameters.contains(&ctp::Parameter::Region(region))
2436 report_unused_parameter(tcx, lifetime_def.lifetime.span,
2437 "lifetime", ®ion.name.to_string());
2441 // (*) This is a horrible concession to reality. I think it'd be
2442 // better to just ban unconstrianed lifetimes outright, but in
2443 // practice people do non-hygenic macros like:
2446 // macro_rules! __impl_slice_eq1 {
2447 // ($Lhs: ty, $Rhs: ty, $Bound: ident) => {
2448 // impl<'a, 'b, A: $Bound, B> PartialEq<$Rhs> for $Lhs where A: PartialEq<B> {
2455 // In a concession to backwards compatbility, we continue to
2456 // permit those, so long as the lifetimes aren't used in
2457 // associated types. I believe this is sound, because lifetimes
2458 // used elsewhere are not projected back out.
2461 fn report_unused_parameter(tcx: &ty::ctxt,
2466 span_err!(tcx.sess, span, E0207,
2467 "the {} parameter `{}` is not constrained by the \
2468 impl trait, self type, or predicates",