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);
1145 ty::AdtKind::Struct,
1146 vec![convert_struct_variant(tcx, did, it.name, 0, def)]
1150 fn convert_enum_def<'tcx>(tcx: &ty::ctxt<'tcx>,
1153 -> ty::AdtDefMaster<'tcx>
1155 fn evaluate_disr_expr<'tcx>(tcx: &ty::ctxt<'tcx>,
1157 e: &hir::Expr) -> Option<ty::Disr> {
1158 debug!("disr expr, checking {}", pprust::expr_to_string(e));
1160 let hint = UncheckedExprHint(repr_ty);
1161 match const_eval::eval_const_expr_partial(tcx, e, hint) {
1162 Ok(ConstVal::Int(val)) => Some(val as ty::Disr),
1163 Ok(ConstVal::Uint(val)) => Some(val as ty::Disr),
1165 let sign_desc = if repr_ty.is_signed() {
1170 span_err!(tcx.sess, e.span, E0079,
1171 "expected {} integer constant",
1176 span_err!(tcx.sess, err.span, E0080,
1177 "constant evaluation error: {}",
1184 fn report_discrim_overflow(tcx: &ty::ctxt,
1187 repr_type: attr::IntType,
1188 prev_val: ty::Disr) {
1189 let computed_value = repr_type.disr_wrap_incr(Some(prev_val));
1190 let computed_value = repr_type.disr_string(computed_value);
1191 let prev_val = repr_type.disr_string(prev_val);
1192 let repr_type = repr_type.to_ty(tcx);
1193 span_err!(tcx.sess, variant_span, E0370,
1194 "enum discriminant overflowed on value after {}: {}; \
1195 set explicitly via {} = {} if that is desired outcome",
1196 prev_val, repr_type, variant_name, computed_value);
1199 fn next_disr(tcx: &ty::ctxt,
1201 repr_type: attr::IntType,
1202 prev_disr_val: Option<ty::Disr>) -> Option<ty::Disr> {
1203 if let Some(prev_disr_val) = prev_disr_val {
1204 let result = repr_type.disr_incr(prev_disr_val);
1205 if let None = result {
1206 report_discrim_overflow(tcx, v.span, &v.node.name.as_str(),
1207 repr_type, prev_disr_val);
1211 Some(ty::INITIAL_DISCRIMINANT_VALUE)
1214 fn convert_enum_variant<'tcx>(tcx: &ty::ctxt<'tcx>,
1217 -> ty::VariantDefData<'tcx, 'tcx>
1219 let did = tcx.map.local_def_id(v.node.id);
1220 let name = v.node.name;
1222 hir::TupleVariantKind(ref va) => {
1223 ty::VariantDefData {
1227 fields: va.iter().map(|&hir::VariantArg { id, .. }| {
1228 ty::FieldDefData::new(
1229 tcx.map.local_def_id(id),
1230 special_idents::unnamed_field.name,
1231 hir::Visibility::Public
1236 hir::StructVariantKind(ref def) => {
1237 convert_struct_variant(tcx, did, name, disr, &def)
1241 let did = tcx.map.local_def_id(it.id);
1242 let repr_hints = tcx.lookup_repr_hints(did);
1243 let (repr_type, repr_type_ty) = tcx.enum_repr_type(repr_hints.get(0));
1244 let mut prev_disr = None;
1245 let variants = def.variants.iter().map(|v| {
1246 let disr = match v.node.disr_expr {
1247 Some(ref e) => evaluate_disr_expr(tcx, repr_type_ty, e),
1248 None => next_disr(tcx, v, repr_type, prev_disr)
1249 }.unwrap_or(repr_type.disr_wrap_incr(prev_disr));
1251 let v = convert_enum_variant(tcx, v, disr);
1252 prev_disr = Some(disr);
1255 tcx.intern_adt_def(tcx.map.local_def_id(it.id), ty::AdtKind::Enum, variants)
1258 /// Ensures that the super-predicates of the trait with def-id
1259 /// trait_def_id are converted and stored. This does NOT ensure that
1260 /// the transitive super-predicates are converted; that is the job of
1261 /// the `ensure_super_predicates()` method in the `AstConv` impl
1262 /// above. Returns a list of trait def-ids that must be ensured as
1263 /// well to guarantee that the transitive superpredicates are
1265 fn ensure_super_predicates_step(ccx: &CrateCtxt,
1266 trait_def_id: DefId)
1271 debug!("ensure_super_predicates_step(trait_def_id={:?})", trait_def_id);
1273 let trait_node_id = if let Some(n) = tcx.map.as_local_node_id(trait_def_id) {
1276 // If this trait comes from an external crate, then all of the
1277 // supertraits it may depend on also must come from external
1278 // crates, and hence all of them already have their
1279 // super-predicates "converted" (and available from crate
1280 // meta-data), so there is no need to transitively test them.
1284 let superpredicates = tcx.super_predicates.borrow().get(&trait_def_id).cloned();
1285 let superpredicates = superpredicates.unwrap_or_else(|| {
1286 let item = match ccx.tcx.map.get(trait_node_id) {
1287 hir_map::NodeItem(item) => item,
1288 _ => ccx.tcx.sess.bug(&format!("trait_node_id {} is not an item", trait_node_id))
1291 let (generics, bounds) = match item.node {
1292 hir::ItemTrait(_, ref generics, ref supertraits, _) => (generics, supertraits),
1293 _ => tcx.sess.span_bug(item.span,
1294 "ensure_super_predicates_step invoked on non-trait"),
1297 // In-scope when converting the superbounds for `Trait` are
1298 // that `Self:Trait` as well as any bounds that appear on the
1300 let trait_def = trait_def_of_item(ccx, item);
1301 let self_predicate = ty::GenericPredicates {
1302 predicates: VecPerParamSpace::new(vec![],
1303 vec![trait_def.trait_ref.to_predicate()],
1306 let scope = &(generics, &self_predicate);
1308 // Convert the bounds that follow the colon, e.g. `Bar+Zed` in `trait Foo : Bar+Zed`.
1309 let self_param_ty = tcx.mk_self_type();
1310 let superbounds1 = compute_bounds(&ccx.icx(scope),
1316 let superbounds1 = superbounds1.predicates(tcx, self_param_ty);
1318 // Convert any explicit superbounds in the where clause,
1319 // e.g. `trait Foo where Self : Bar`:
1320 let superbounds2 = generics.get_type_parameter_bounds(&ccx.icx(scope), item.span, item.id);
1322 // Combine the two lists to form the complete set of superbounds:
1323 let superbounds = superbounds1.into_iter().chain(superbounds2).collect();
1324 let superpredicates = ty::GenericPredicates {
1325 predicates: VecPerParamSpace::new(superbounds, vec![], vec![])
1327 debug!("superpredicates for trait {:?} = {:?}",
1328 tcx.map.local_def_id(item.id),
1331 tcx.super_predicates.borrow_mut().insert(trait_def_id, superpredicates.clone());
1336 let def_ids: Vec<_> = superpredicates.predicates
1338 .filter_map(|p| p.to_opt_poly_trait_ref())
1339 .map(|tr| tr.def_id())
1342 debug!("ensure_super_predicates_step: def_ids={:?}", def_ids);
1347 fn trait_def_of_item<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
1349 -> &'tcx ty::TraitDef<'tcx>
1351 let def_id = ccx.tcx.map.local_def_id(it.id);
1354 if let Some(def) = tcx.trait_defs.borrow().get(&def_id) {
1358 let (unsafety, generics, items) = match it.node {
1359 hir::ItemTrait(unsafety, ref generics, _, ref items) => (unsafety, generics, items),
1360 _ => tcx.sess.span_bug(it.span, "trait_def_of_item invoked on non-trait"),
1363 let paren_sugar = tcx.has_attr(def_id, "rustc_paren_sugar");
1364 if paren_sugar && !ccx.tcx.sess.features.borrow().unboxed_closures {
1365 ccx.tcx.sess.span_err(
1367 "the `#[rustc_paren_sugar]` attribute is a temporary means of controlling \
1368 which traits can use parenthetical notation");
1369 fileline_help!(ccx.tcx.sess, it.span,
1370 "add `#![feature(unboxed_closures)]` to \
1371 the crate attributes to use it");
1374 let substs = ccx.tcx.mk_substs(mk_trait_substs(ccx, generics));
1376 let ty_generics = ty_generics_for_trait(ccx, it.id, substs, generics);
1378 let associated_type_names: Vec<_> = items.iter().filter_map(|trait_item| {
1379 match trait_item.node {
1380 hir::TypeTraitItem(..) => Some(trait_item.name),
1385 let trait_ref = ty::TraitRef {
1390 let trait_def = ty::TraitDef {
1391 paren_sugar: paren_sugar,
1393 generics: ty_generics,
1394 trait_ref: trait_ref,
1395 associated_type_names: associated_type_names,
1396 nonblanket_impls: RefCell::new(FnvHashMap()),
1397 blanket_impls: RefCell::new(vec![]),
1398 flags: Cell::new(ty::TraitFlags::NO_TRAIT_FLAGS)
1401 return tcx.intern_trait_def(trait_def);
1403 fn mk_trait_substs<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
1404 generics: &hir::Generics)
1409 // Creates a no-op substitution for the trait's type parameters.
1414 .map(|(i, def)| ty::ReEarlyBound(ty::EarlyBoundRegion {
1415 def_id: tcx.map.local_def_id(def.lifetime.id),
1418 name: def.lifetime.name
1422 // Start with the generics in the type parameters...
1427 .map(|(i, def)| tcx.mk_param(TypeSpace,
1428 i as u32, def.name))
1431 // ...and also create the `Self` parameter.
1432 let self_ty = tcx.mk_self_type();
1434 Substs::new_trait(types, regions, self_ty)
1438 fn trait_defines_associated_type_named(ccx: &CrateCtxt,
1439 trait_node_id: ast::NodeId,
1440 assoc_name: ast::Name)
1443 let item = match ccx.tcx.map.get(trait_node_id) {
1444 hir_map::NodeItem(item) => item,
1445 _ => ccx.tcx.sess.bug(&format!("trait_node_id {} is not an item", trait_node_id))
1448 let trait_items = match item.node {
1449 hir::ItemTrait(_, _, _, ref trait_items) => trait_items,
1450 _ => ccx.tcx.sess.bug(&format!("trait_node_id {} is not a trait", trait_node_id))
1453 trait_items.iter().any(|trait_item| {
1454 match trait_item.node {
1455 hir::TypeTraitItem(..) => trait_item.name == assoc_name,
1461 fn convert_trait_predicates<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>, it: &hir::Item) {
1463 let trait_def = trait_def_of_item(ccx, it);
1465 let def_id = ccx.tcx.map.local_def_id(it.id);
1467 let (generics, items) = match it.node {
1468 hir::ItemTrait(_, ref generics, _, ref items) => (generics, items),
1472 &format!("trait_def_of_item invoked on {:?}", s));
1476 let super_predicates = ccx.tcx.lookup_super_predicates(def_id);
1478 // `ty_generic_predicates` below will consider the bounds on the type
1479 // parameters (including `Self`) and the explicit where-clauses,
1480 // but to get the full set of predicates on a trait we need to add
1481 // in the supertrait bounds and anything declared on the
1482 // associated types.
1483 let mut base_predicates = super_predicates;
1485 // Add in a predicate that `Self:Trait` (where `Trait` is the
1486 // current trait). This is needed for builtin bounds.
1487 let self_predicate = trait_def.trait_ref.to_poly_trait_ref().to_predicate();
1488 base_predicates.predicates.push(SelfSpace, self_predicate);
1490 // add in the explicit where-clauses
1491 let mut trait_predicates =
1492 ty_generic_predicates(ccx, TypeSpace, generics, &base_predicates);
1494 let assoc_predicates = predicates_for_associated_types(ccx,
1497 trait_def.trait_ref,
1499 trait_predicates.predicates.extend(TypeSpace, assoc_predicates.into_iter());
1501 let prev_predicates = tcx.predicates.borrow_mut().insert(def_id, trait_predicates);
1502 assert!(prev_predicates.is_none());
1506 fn predicates_for_associated_types<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
1507 ast_generics: &hir::Generics,
1508 trait_predicates: &ty::GenericPredicates<'tcx>,
1509 self_trait_ref: ty::TraitRef<'tcx>,
1510 trait_items: &[P<hir::TraitItem>])
1511 -> Vec<ty::Predicate<'tcx>>
1513 trait_items.iter().flat_map(|trait_item| {
1514 let bounds = match trait_item.node {
1515 hir::TypeTraitItem(ref bounds, _) => bounds,
1517 return vec!().into_iter();
1521 let assoc_ty = ccx.tcx.mk_projection(self_trait_ref,
1524 let bounds = compute_bounds(&ccx.icx(&(ast_generics, trait_predicates)),
1527 SizedByDefault::Yes,
1530 bounds.predicates(ccx.tcx, assoc_ty).into_iter()
1535 fn type_scheme_of_def_id<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
1537 -> ty::TypeScheme<'tcx>
1539 if let Some(node_id) = ccx.tcx.map.as_local_node_id(def_id) {
1540 match ccx.tcx.map.find(node_id) {
1541 Some(hir_map::NodeItem(item)) => {
1542 type_scheme_of_item(ccx, &*item)
1544 Some(hir_map::NodeForeignItem(foreign_item)) => {
1545 let abi = ccx.tcx.map.get_foreign_abi(node_id);
1546 type_scheme_of_foreign_item(ccx, &*foreign_item, abi)
1549 ccx.tcx.sess.bug(&format!("unexpected sort of node \
1550 in get_item_type_scheme(): {:?}",
1555 ccx.tcx.lookup_item_type(def_id)
1559 fn type_scheme_of_item<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
1561 -> ty::TypeScheme<'tcx>
1563 memoized(&ccx.tcx.tcache,
1564 ccx.tcx.map.local_def_id(it.id),
1565 |_| compute_type_scheme_of_item(ccx, it))
1568 fn compute_type_scheme_of_item<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
1570 -> ty::TypeScheme<'tcx>
1574 hir::ItemStatic(ref t, _, _) | hir::ItemConst(ref t, _) => {
1575 let ty = ccx.icx(&()).to_ty(&ExplicitRscope, &**t);
1576 ty::TypeScheme { ty: ty, generics: ty::Generics::empty() }
1578 hir::ItemFn(ref decl, unsafety, _, abi, ref generics, _) => {
1579 let ty_generics = ty_generics_for_fn(ccx, generics, &ty::Generics::empty());
1580 let tofd = astconv::ty_of_bare_fn(&ccx.icx(generics), unsafety, abi, &**decl);
1581 let ty = tcx.mk_fn(Some(ccx.tcx.map.local_def_id(it.id)), tcx.mk_bare_fn(tofd));
1582 ty::TypeScheme { ty: ty, generics: ty_generics }
1584 hir::ItemTy(ref t, ref generics) => {
1585 let ty_generics = ty_generics_for_type_or_impl(ccx, generics);
1586 let ty = ccx.icx(generics).to_ty(&ExplicitRscope, &**t);
1587 ty::TypeScheme { ty: ty, generics: ty_generics }
1589 hir::ItemEnum(ref ei, ref generics) => {
1590 let ty_generics = ty_generics_for_type_or_impl(ccx, generics);
1591 let substs = mk_item_substs(ccx, &ty_generics);
1592 let def = convert_enum_def(tcx, it, ei);
1593 let t = tcx.mk_enum(def, tcx.mk_substs(substs));
1594 ty::TypeScheme { ty: t, generics: ty_generics }
1596 hir::ItemStruct(ref si, ref generics) => {
1597 let ty_generics = ty_generics_for_type_or_impl(ccx, generics);
1598 let substs = mk_item_substs(ccx, &ty_generics);
1599 let def = convert_struct_def(tcx, it, si);
1600 let t = tcx.mk_struct(def, tcx.mk_substs(substs));
1601 ty::TypeScheme { ty: t, generics: ty_generics }
1603 hir::ItemDefaultImpl(..) |
1604 hir::ItemTrait(..) |
1607 hir::ItemForeignMod(..) |
1608 hir::ItemExternCrate(..) |
1609 hir::ItemUse(..) => {
1612 &format!("compute_type_scheme_of_item: unexpected item type: {:?}",
1618 fn convert_typed_item<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
1620 -> (ty::TypeScheme<'tcx>, ty::GenericPredicates<'tcx>)
1624 let tag = type_scheme_of_item(ccx, it);
1625 let scheme = TypeScheme { generics: tag.generics, ty: tag.ty };
1626 let predicates = match it.node {
1627 hir::ItemStatic(..) | hir::ItemConst(..) => {
1628 ty::GenericPredicates::empty()
1630 hir::ItemFn(_, _, _, _, ref ast_generics, _) => {
1631 ty_generic_predicates_for_fn(ccx, ast_generics, &ty::GenericPredicates::empty())
1633 hir::ItemTy(_, ref generics) => {
1634 ty_generic_predicates_for_type_or_impl(ccx, generics)
1636 hir::ItemEnum(_, ref generics) => {
1637 ty_generic_predicates_for_type_or_impl(ccx, generics)
1639 hir::ItemStruct(_, ref generics) => {
1640 ty_generic_predicates_for_type_or_impl(ccx, generics)
1642 hir::ItemDefaultImpl(..) |
1643 hir::ItemTrait(..) |
1644 hir::ItemExternCrate(..) |
1648 hir::ItemForeignMod(..) => {
1651 &format!("compute_type_scheme_of_item: unexpected item type: {:?}",
1656 let prev_predicates = tcx.predicates.borrow_mut().insert(ccx.tcx.map.local_def_id(it.id),
1657 predicates.clone());
1658 assert!(prev_predicates.is_none());
1661 if tcx.has_attr(ccx.tcx.map.local_def_id(it.id), "rustc_object_lifetime_default") {
1662 let object_lifetime_default_reprs: String =
1663 scheme.generics.types.iter()
1664 .map(|t| match t.object_lifetime_default {
1665 ty::ObjectLifetimeDefault::Specific(r) => r.to_string(),
1666 d => format!("{:?}", d),
1668 .collect::<Vec<String>>()
1671 tcx.sess.span_err(it.span, &object_lifetime_default_reprs);
1674 return (scheme, predicates);
1677 fn type_scheme_of_foreign_item<'a, 'tcx>(
1678 ccx: &CrateCtxt<'a, 'tcx>,
1679 it: &hir::ForeignItem,
1681 -> ty::TypeScheme<'tcx>
1683 memoized(&ccx.tcx.tcache,
1684 ccx.tcx.map.local_def_id(it.id),
1685 |_| compute_type_scheme_of_foreign_item(ccx, it, abi))
1688 fn compute_type_scheme_of_foreign_item<'a, 'tcx>(
1689 ccx: &CrateCtxt<'a, 'tcx>,
1690 it: &hir::ForeignItem,
1692 -> ty::TypeScheme<'tcx>
1695 hir::ForeignItemFn(ref fn_decl, ref generics) => {
1696 compute_type_scheme_of_foreign_fn_decl(ccx, fn_decl, generics, abi)
1698 hir::ForeignItemStatic(ref t, _) => {
1700 generics: ty::Generics::empty(),
1701 ty: ast_ty_to_ty(&ccx.icx(&()), &ExplicitRscope, t)
1707 fn convert_foreign_item<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
1708 it: &hir::ForeignItem)
1710 // For reasons I cannot fully articulate, I do so hate the AST
1711 // map, and I regard each time that I use it as a personal and
1712 // moral failing, but at the moment it seems like the only
1713 // convenient way to extract the ABI. - ndm
1715 let abi = tcx.map.get_foreign_abi(it.id);
1717 let scheme = type_scheme_of_foreign_item(ccx, it, abi);
1718 write_ty_to_tcx(ccx.tcx, it.id, scheme.ty);
1720 let predicates = match it.node {
1721 hir::ForeignItemFn(_, ref generics) => {
1722 ty_generic_predicates_for_fn(ccx, generics, &ty::GenericPredicates::empty())
1724 hir::ForeignItemStatic(..) => {
1725 ty::GenericPredicates::empty()
1729 let prev_predicates = tcx.predicates.borrow_mut().insert(ccx.tcx.map.local_def_id(it.id),
1731 assert!(prev_predicates.is_none());
1734 fn ty_generics_for_type_or_impl<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
1735 generics: &hir::Generics)
1736 -> ty::Generics<'tcx> {
1737 ty_generics(ccx, TypeSpace, generics, &ty::Generics::empty())
1740 fn ty_generic_predicates_for_type_or_impl<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
1741 generics: &hir::Generics)
1742 -> ty::GenericPredicates<'tcx>
1744 ty_generic_predicates(ccx, TypeSpace, generics, &ty::GenericPredicates::empty())
1747 fn ty_generics_for_trait<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
1748 trait_id: ast::NodeId,
1749 substs: &'tcx Substs<'tcx>,
1750 ast_generics: &hir::Generics)
1751 -> ty::Generics<'tcx>
1753 debug!("ty_generics_for_trait(trait_id={:?}, substs={:?})",
1754 ccx.tcx.map.local_def_id(trait_id), substs);
1756 let mut generics = ty_generics_for_type_or_impl(ccx, ast_generics);
1758 // Add in the self type parameter.
1760 // Something of a hack: use the node id for the trait, also as
1761 // the node id for the Self type parameter.
1762 let param_id = trait_id;
1764 let parent = ccx.tcx.map.get_parent(param_id);
1766 let def = ty::TypeParameterDef {
1769 name: special_idents::type_self.name,
1770 def_id: ccx.tcx.map.local_def_id(param_id),
1771 default_def_id: ccx.tcx.map.local_def_id(parent),
1773 object_lifetime_default: ty::ObjectLifetimeDefault::BaseDefault,
1776 ccx.tcx.ty_param_defs.borrow_mut().insert(param_id, def.clone());
1778 generics.types.push(SelfSpace, def);
1783 fn ty_generics_for_fn<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
1784 generics: &hir::Generics,
1785 base_generics: &ty::Generics<'tcx>)
1786 -> ty::Generics<'tcx>
1788 ty_generics(ccx, FnSpace, generics, base_generics)
1791 fn ty_generic_predicates_for_fn<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
1792 generics: &hir::Generics,
1793 base_predicates: &ty::GenericPredicates<'tcx>)
1794 -> ty::GenericPredicates<'tcx>
1796 ty_generic_predicates(ccx, FnSpace, generics, base_predicates)
1799 // Add the Sized bound, unless the type parameter is marked as `?Sized`.
1800 fn add_unsized_bound<'tcx>(astconv: &AstConv<'tcx>,
1801 bounds: &mut ty::BuiltinBounds,
1802 ast_bounds: &[hir::TyParamBound],
1805 let tcx = astconv.tcx();
1807 // Try to find an unbound in bounds.
1808 let mut unbound = None;
1809 for ab in ast_bounds {
1810 if let &hir::TraitTyParamBound(ref ptr, hir::TraitBoundModifier::Maybe) = ab {
1811 if unbound.is_none() {
1812 assert!(ptr.bound_lifetimes.is_empty());
1813 unbound = Some(ptr.trait_ref.clone());
1815 span_err!(tcx.sess, span, E0203,
1816 "type parameter has more than one relaxed default \
1817 bound, only one is supported");
1822 let kind_id = tcx.lang_items.require(SizedTraitLangItem);
1825 // FIXME(#8559) currently requires the unbound to be built-in.
1826 let trait_def_id = tcx.trait_ref_to_def_id(tpb);
1828 Ok(kind_id) if trait_def_id != kind_id => {
1829 tcx.sess.span_warn(span,
1830 "default bound relaxed for a type parameter, but \
1831 this does nothing because the given bound is not \
1832 a default. Only `?Sized` is supported");
1833 tcx.try_add_builtin_trait(kind_id, bounds);
1838 _ if kind_id.is_ok() => {
1839 tcx.try_add_builtin_trait(kind_id.unwrap(), bounds);
1841 // No lang item for Sized, so we can't add it as a bound.
1846 /// Returns the early-bound lifetimes declared in this generics
1847 /// listing. For anything other than fns/methods, this is just all
1848 /// the lifetimes that are declared. For fns or methods, we have to
1849 /// screen out those that do not appear in any where-clauses etc using
1850 /// `resolve_lifetime::early_bound_lifetimes`.
1851 fn early_bound_lifetimes_from_generics(space: ParamSpace,
1852 ast_generics: &hir::Generics)
1853 -> Vec<hir::LifetimeDef>
1856 SelfSpace | TypeSpace => ast_generics.lifetimes.to_vec(),
1857 FnSpace => resolve_lifetime::early_bound_lifetimes(ast_generics),
1861 fn ty_generic_predicates<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
1863 ast_generics: &hir::Generics,
1864 base_predicates: &ty::GenericPredicates<'tcx>)
1865 -> ty::GenericPredicates<'tcx>
1868 let mut result = base_predicates.clone();
1870 // Collect the predicates that were written inline by the user on each
1871 // type parameter (e.g., `<T:Foo>`).
1872 for (index, param) in ast_generics.ty_params.iter().enumerate() {
1873 let index = index as u32;
1874 let param_ty = ty::ParamTy::new(space, index, param.name).to_ty(ccx.tcx);
1875 let bounds = compute_bounds(&ccx.icx(&(base_predicates, ast_generics)),
1878 SizedByDefault::Yes,
1880 let predicates = bounds.predicates(ccx.tcx, param_ty);
1881 result.predicates.extend(space, predicates.into_iter());
1884 // Collect the region predicates that were declared inline as
1885 // well. In the case of parameters declared on a fn or method, we
1886 // have to be careful to only iterate over early-bound regions.
1887 let early_lifetimes = early_bound_lifetimes_from_generics(space, ast_generics);
1888 for (index, param) in early_lifetimes.iter().enumerate() {
1889 let index = index as u32;
1890 let def_id = tcx.map.local_def_id(param.lifetime.id);
1892 ty::ReEarlyBound(ty::EarlyBoundRegion {
1896 name: param.lifetime.name
1898 for bound in ¶m.bounds {
1899 let bound_region = ast_region_to_region(ccx.tcx, bound);
1900 let outlives = ty::Binder(ty::OutlivesPredicate(region, bound_region));
1901 result.predicates.push(space, outlives.to_predicate());
1905 // Add in the bounds that appear in the where-clause
1906 let where_clause = &ast_generics.where_clause;
1907 for predicate in &where_clause.predicates {
1909 &hir::WherePredicate::BoundPredicate(ref bound_pred) => {
1910 let ty = ast_ty_to_ty(&ccx.icx(&(base_predicates, ast_generics)),
1912 &*bound_pred.bounded_ty);
1914 for bound in bound_pred.bounds.iter() {
1916 &hir::TyParamBound::TraitTyParamBound(ref poly_trait_ref, _) => {
1917 let mut projections = Vec::new();
1920 conv_poly_trait_ref(&ccx.icx(&(base_predicates, ast_generics)),
1925 result.predicates.push(space, trait_ref.to_predicate());
1927 for projection in &projections {
1928 result.predicates.push(space, projection.to_predicate());
1932 &hir::TyParamBound::RegionTyParamBound(ref lifetime) => {
1933 let region = ast_region_to_region(tcx, lifetime);
1934 let pred = ty::Binder(ty::OutlivesPredicate(ty, region));
1935 result.predicates.push(space, ty::Predicate::TypeOutlives(pred))
1941 &hir::WherePredicate::RegionPredicate(ref region_pred) => {
1942 let r1 = ast_region_to_region(tcx, ®ion_pred.lifetime);
1943 for bound in ®ion_pred.bounds {
1944 let r2 = ast_region_to_region(tcx, bound);
1945 let pred = ty::Binder(ty::OutlivesPredicate(r1, r2));
1946 result.predicates.push(space, ty::Predicate::RegionOutlives(pred))
1950 &hir::WherePredicate::EqPredicate(ref eq_pred) => {
1952 tcx.sess.span_bug(eq_pred.span,
1953 "Equality constraints are not yet \
1954 implemented (#20041)")
1962 fn ty_generics<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
1964 ast_generics: &hir::Generics,
1965 base_generics: &ty::Generics<'tcx>)
1966 -> ty::Generics<'tcx>
1969 let mut result = base_generics.clone();
1971 let early_lifetimes = early_bound_lifetimes_from_generics(space, ast_generics);
1972 for (i, l) in early_lifetimes.iter().enumerate() {
1973 let bounds = l.bounds.iter()
1974 .map(|l| ast_region_to_region(tcx, l))
1976 let def = ty::RegionParameterDef { name: l.lifetime.name,
1979 def_id: ccx.tcx.map.local_def_id(l.lifetime.id),
1981 result.regions.push(space, def);
1984 assert!(result.types.is_empty_in(space));
1986 // Now create the real type parameters.
1987 for i in 0..ast_generics.ty_params.len() {
1988 let def = get_or_create_type_parameter_def(ccx, ast_generics, space, i as u32);
1989 debug!("ty_generics: def for type param: {:?}, {:?}", def, space);
1990 result.types.push(space, def);
1996 fn convert_default_type_parameter<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
2002 let ty = ast_ty_to_ty(&ccx.icx(&()), &ExplicitRscope, &path);
2004 for leaf_ty in ty.walk() {
2005 if let ty::TyParam(p) = leaf_ty.sty {
2006 if p.space == space && p.idx >= index {
2007 span_err!(ccx.tcx.sess, path.span, E0128,
2008 "type parameters with a default cannot use \
2009 forward declared identifiers");
2011 return ccx.tcx.types.err
2019 fn get_or_create_type_parameter_def<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
2020 ast_generics: &hir::Generics,
2023 -> ty::TypeParameterDef<'tcx>
2025 let param = &ast_generics.ty_params[index as usize];
2028 match tcx.ty_param_defs.borrow().get(¶m.id) {
2029 Some(d) => { return d.clone(); }
2033 let default = param.default.as_ref().map(
2034 |def| convert_default_type_parameter(ccx, def, space, index)
2037 let object_lifetime_default =
2038 compute_object_lifetime_default(ccx, param.id,
2039 ¶m.bounds, &ast_generics.where_clause);
2041 let parent = tcx.map.get_parent(param.id);
2043 let def = ty::TypeParameterDef {
2047 def_id: ccx.tcx.map.local_def_id(param.id),
2048 default_def_id: ccx.tcx.map.local_def_id(parent),
2050 object_lifetime_default: object_lifetime_default,
2053 tcx.ty_param_defs.borrow_mut().insert(param.id, def.clone());
2058 /// Scan the bounds and where-clauses on a parameter to extract bounds
2059 /// of the form `T:'a` so as to determine the `ObjectLifetimeDefault`.
2060 /// This runs as part of computing the minimal type scheme, so we
2061 /// intentionally avoid just asking astconv to convert all the where
2062 /// clauses into a `ty::Predicate`. This is because that could induce
2063 /// artificial cycles.
2064 fn compute_object_lifetime_default<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
2065 param_id: ast::NodeId,
2066 param_bounds: &[hir::TyParamBound],
2067 where_clause: &hir::WhereClause)
2068 -> ty::ObjectLifetimeDefault
2070 let inline_bounds = from_bounds(ccx, param_bounds);
2071 let where_bounds = from_predicates(ccx, param_id, &where_clause.predicates);
2072 let all_bounds: HashSet<_> = inline_bounds.into_iter()
2073 .chain(where_bounds)
2075 return if all_bounds.len() > 1 {
2076 ty::ObjectLifetimeDefault::Ambiguous
2077 } else if all_bounds.len() == 0 {
2078 ty::ObjectLifetimeDefault::BaseDefault
2080 ty::ObjectLifetimeDefault::Specific(
2081 all_bounds.into_iter().next().unwrap())
2084 fn from_bounds<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
2085 bounds: &[hir::TyParamBound])
2089 .filter_map(|bound| {
2091 hir::TraitTyParamBound(..) =>
2093 hir::RegionTyParamBound(ref lifetime) =>
2094 Some(astconv::ast_region_to_region(ccx.tcx, lifetime)),
2100 fn from_predicates<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
2101 param_id: ast::NodeId,
2102 predicates: &[hir::WherePredicate])
2106 .flat_map(|predicate| {
2108 hir::WherePredicate::BoundPredicate(ref data) => {
2109 if data.bound_lifetimes.is_empty() &&
2110 is_param(ccx.tcx, &data.bounded_ty, param_id)
2112 from_bounds(ccx, &data.bounds).into_iter()
2114 Vec::new().into_iter()
2117 hir::WherePredicate::RegionPredicate(..) |
2118 hir::WherePredicate::EqPredicate(..) => {
2119 Vec::new().into_iter()
2127 enum SizedByDefault { Yes, No, }
2129 /// Translate the AST's notion of ty param bounds (which are an enum consisting of a newtyped Ty or
2130 /// a region) to ty's notion of ty param bounds, which can either be user-defined traits, or the
2131 /// built-in trait (formerly known as kind): Send.
2132 fn compute_bounds<'tcx>(astconv: &AstConv<'tcx>,
2133 param_ty: ty::Ty<'tcx>,
2134 ast_bounds: &[hir::TyParamBound],
2135 sized_by_default: SizedByDefault,
2137 -> astconv::Bounds<'tcx>
2140 conv_param_bounds(astconv,
2145 if let SizedByDefault::Yes = sized_by_default {
2146 add_unsized_bound(astconv,
2147 &mut bounds.builtin_bounds,
2152 bounds.trait_bounds.sort_by(|a,b| a.def_id().cmp(&b.def_id()));
2157 /// Converts a specific TyParamBound from the AST into a set of
2158 /// predicates that apply to the self-type. A vector is returned
2159 /// because this can be anywhere from 0 predicates (`T:?Sized` adds no
2160 /// predicates) to 1 (`T:Foo`) to many (`T:Bar<X=i32>` adds `T:Bar`
2161 /// and `<T as Bar>::X == i32`).
2162 fn predicates_from_bound<'tcx>(astconv: &AstConv<'tcx>,
2164 bound: &hir::TyParamBound)
2165 -> Vec<ty::Predicate<'tcx>>
2168 hir::TraitTyParamBound(ref tr, hir::TraitBoundModifier::None) => {
2169 let mut projections = Vec::new();
2170 let pred = conv_poly_trait_ref(astconv, param_ty, tr, &mut projections);
2171 projections.into_iter()
2172 .map(|p| p.to_predicate())
2173 .chain(Some(pred.to_predicate()))
2176 hir::RegionTyParamBound(ref lifetime) => {
2177 let region = ast_region_to_region(astconv.tcx(), lifetime);
2178 let pred = ty::Binder(ty::OutlivesPredicate(param_ty, region));
2179 vec![ty::Predicate::TypeOutlives(pred)]
2181 hir::TraitTyParamBound(_, hir::TraitBoundModifier::Maybe) => {
2187 fn conv_poly_trait_ref<'tcx>(astconv: &AstConv<'tcx>,
2189 trait_ref: &hir::PolyTraitRef,
2190 projections: &mut Vec<ty::PolyProjectionPredicate<'tcx>>)
2191 -> ty::PolyTraitRef<'tcx>
2193 astconv::instantiate_poly_trait_ref(astconv,
2200 fn conv_param_bounds<'a,'tcx>(astconv: &AstConv<'tcx>,
2202 param_ty: ty::Ty<'tcx>,
2203 ast_bounds: &[hir::TyParamBound])
2204 -> astconv::Bounds<'tcx>
2206 let tcx = astconv.tcx();
2207 let astconv::PartitionedBounds {
2211 } = astconv::partition_bounds(tcx, span, &ast_bounds);
2213 let mut projection_bounds = Vec::new();
2215 let trait_bounds: Vec<ty::PolyTraitRef> =
2217 .map(|bound| conv_poly_trait_ref(astconv,
2220 &mut projection_bounds))
2223 let region_bounds: Vec<ty::Region> =
2224 region_bounds.into_iter()
2225 .map(|r| ast_region_to_region(tcx, r))
2229 region_bounds: region_bounds,
2230 builtin_bounds: builtin_bounds,
2231 trait_bounds: trait_bounds,
2232 projection_bounds: projection_bounds,
2236 fn compute_type_scheme_of_foreign_fn_decl<'a, 'tcx>(
2237 ccx: &CrateCtxt<'a, 'tcx>,
2239 ast_generics: &hir::Generics,
2241 -> ty::TypeScheme<'tcx>
2243 for i in &decl.inputs {
2244 match (*i).pat.node {
2245 hir::PatIdent(_, _, _) => (),
2246 hir::PatWild(hir::PatWildSingle) => (),
2248 span_err!(ccx.tcx.sess, (*i).pat.span, E0130,
2249 "patterns aren't allowed in foreign function declarations");
2254 let ty_generics = ty_generics_for_fn(ccx, ast_generics, &ty::Generics::empty());
2256 let rb = BindingRscope::new();
2257 let input_tys = decl.inputs
2259 .map(|a| ty_of_arg(&ccx.icx(ast_generics), &rb, a, None))
2262 let output = match decl.output {
2263 hir::Return(ref ty) =>
2264 ty::FnConverging(ast_ty_to_ty(&ccx.icx(ast_generics), &rb, &**ty)),
2265 hir::DefaultReturn(..) =>
2266 ty::FnConverging(ccx.tcx.mk_nil()),
2267 hir::NoReturn(..) =>
2271 let t_fn = ccx.tcx.mk_fn(None,
2272 ccx.tcx.mk_bare_fn(ty::BareFnTy {
2274 unsafety: hir::Unsafety::Unsafe,
2275 sig: ty::Binder(ty::FnSig {inputs: input_tys,
2277 variadic: decl.variadic}),
2281 generics: ty_generics,
2286 fn mk_item_substs<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
2287 ty_generics: &ty::Generics<'tcx>)
2291 ty_generics.types.map(
2292 |def| ccx.tcx.mk_param_from_def(def));
2295 ty_generics.regions.map(
2296 |def| def.to_early_bound_region());
2298 Substs::new(types, regions)
2301 /// Verifies that the explicit self type of a method matches the impl
2302 /// or trait. This is a bit weird but basically because right now we
2303 /// don't handle the general case, but instead map it to one of
2304 /// several pre-defined options using various heuristics, this method
2305 /// comes back to check after the fact that explicit type the user
2306 /// wrote actually matches what the pre-defined option said.
2307 fn check_method_self_type<'a, 'tcx, RS:RegionScope>(
2308 ccx: &CrateCtxt<'a, 'tcx>,
2310 method_type: Rc<ty::Method<'tcx>>,
2311 required_type: Ty<'tcx>,
2312 explicit_self: &hir::ExplicitSelf,
2313 body_id: ast::NodeId)
2316 if let hir::SelfExplicit(ref ast_type, _) = explicit_self.node {
2317 let typ = ccx.icx(&method_type.predicates).to_ty(rs, &**ast_type);
2318 let base_type = match typ.sty {
2319 ty::TyRef(_, tm) => tm.ty,
2320 ty::TyBox(typ) => typ,
2324 let body_scope = tcx.region_maps.item_extent(body_id);
2326 // "Required type" comes from the trait definition. It may
2327 // contain late-bound regions from the method, but not the
2328 // trait (since traits only have early-bound region
2330 assert!(!base_type.has_regions_escaping_depth(1));
2331 let required_type_free =
2332 liberate_early_bound_regions(
2334 &tcx.liberate_late_bound_regions(body_scope, &ty::Binder(required_type)));
2336 // The "base type" comes from the impl. It too may have late-bound
2337 // regions from the method.
2338 assert!(!base_type.has_regions_escaping_depth(1));
2339 let base_type_free =
2340 liberate_early_bound_regions(
2342 &tcx.liberate_late_bound_regions(body_scope, &ty::Binder(base_type)));
2344 debug!("required_type={:?} required_type_free={:?} \
2345 base_type={:?} base_type_free={:?}",
2351 let infcx = infer::new_infer_ctxt(tcx, &tcx.tables, None, false);
2352 drop(::require_same_types(tcx,
2359 format!("mismatched self type: expected `{}`",
2363 // We could conceviably add more free-region relations here,
2364 // but since this code is just concerned with checking that
2365 // the `&Self` types etc match up, it's not really necessary.
2366 // It would just allow people to be more approximate in some
2367 // cases. In any case, we can do it later as we feel the need;
2368 // I'd like this function to go away eventually.
2369 let free_regions = FreeRegionMap::new();
2371 infcx.resolve_regions_and_report_errors(&free_regions, body_id);
2374 fn liberate_early_bound_regions<'tcx,T>(
2375 tcx: &ty::ctxt<'tcx>,
2376 scope: region::CodeExtent,
2379 where T : TypeFoldable<'tcx>
2382 * Convert early-bound regions into free regions; normally this is done by
2383 * applying the `free_substs` from the `ParameterEnvironment`, but this particular
2384 * method-self-type check is kind of hacky and done very early in the process,
2385 * before we really have a `ParameterEnvironment` to check.
2388 tcx.fold_regions(value, &mut false, |region, _| {
2390 ty::ReEarlyBound(data) => {
2391 ty::ReFree(ty::FreeRegion {
2393 bound_region: ty::BrNamed(data.def_id, data.name)
2402 /// Checks that all the type parameters on an impl
2403 fn enforce_impl_params_are_constrained<'tcx>(tcx: &ty::ctxt<'tcx>,
2404 ast_generics: &hir::Generics,
2406 impl_items: &[P<hir::ImplItem>])
2408 let impl_scheme = tcx.lookup_item_type(impl_def_id);
2409 let impl_predicates = tcx.lookup_predicates(impl_def_id);
2410 let impl_trait_ref = tcx.impl_trait_ref(impl_def_id);
2412 // The trait reference is an input, so find all type parameters
2413 // reachable from there, to start (if this is an inherent impl,
2414 // then just examine the self type).
2415 let mut input_parameters: HashSet<_> =
2416 ctp::parameters_for_type(impl_scheme.ty).into_iter().collect();
2417 if let Some(ref trait_ref) = impl_trait_ref {
2418 input_parameters.extend(ctp::parameters_for_trait_ref(trait_ref));
2421 ctp::identify_constrained_type_params(tcx,
2422 impl_predicates.predicates.as_slice(),
2424 &mut input_parameters);
2426 for (index, ty_param) in ast_generics.ty_params.iter().enumerate() {
2427 let param_ty = ty::ParamTy { space: TypeSpace,
2429 name: ty_param.name };
2430 if !input_parameters.contains(&ctp::Parameter::Type(param_ty)) {
2431 report_unused_parameter(tcx, ty_param.span, "type", ¶m_ty.to_string());
2435 // Every lifetime used in an associated type must be constrained.
2437 let lifetimes_in_associated_types: HashSet<_> =
2439 .map(|item| tcx.impl_or_trait_item(tcx.map.local_def_id(item.id)))
2440 .filter_map(|item| match item {
2441 ty::TypeTraitItem(ref assoc_ty) => assoc_ty.ty,
2442 ty::ConstTraitItem(..) | ty::MethodTraitItem(..) => None
2444 .flat_map(|ty| ctp::parameters_for_type(ty))
2445 .filter_map(|p| match p {
2446 ctp::Parameter::Type(_) => None,
2447 ctp::Parameter::Region(r) => Some(r),
2451 for (index, lifetime_def) in ast_generics.lifetimes.iter().enumerate() {
2452 let def_id = tcx.map.local_def_id(lifetime_def.lifetime.id);
2453 let region = ty::EarlyBoundRegion { def_id: def_id,
2455 index: index as u32,
2456 name: lifetime_def.lifetime.name };
2458 lifetimes_in_associated_types.contains(®ion) && // (*)
2459 !input_parameters.contains(&ctp::Parameter::Region(region))
2461 report_unused_parameter(tcx, lifetime_def.lifetime.span,
2462 "lifetime", ®ion.name.to_string());
2466 // (*) This is a horrible concession to reality. I think it'd be
2467 // better to just ban unconstrianed lifetimes outright, but in
2468 // practice people do non-hygenic macros like:
2471 // macro_rules! __impl_slice_eq1 {
2472 // ($Lhs: ty, $Rhs: ty, $Bound: ident) => {
2473 // impl<'a, 'b, A: $Bound, B> PartialEq<$Rhs> for $Lhs where A: PartialEq<B> {
2480 // In a concession to backwards compatbility, we continue to
2481 // permit those, so long as the lifetimes aren't used in
2482 // associated types. I believe this is sound, because lifetimes
2483 // used elsewhere are not projected back out.
2486 fn report_unused_parameter(tcx: &ty::ctxt,
2491 span_err!(tcx.sess, span, E0207,
2492 "the {} parameter `{}` is not constrained by the \
2493 impl trait, self type, or predicates",