1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! Trait Resolution. See README.md for an overview of how this works.
13 pub use self::SelectionError::*;
14 pub use self::FulfillmentErrorCode::*;
15 pub use self::Vtable::*;
16 pub use self::ObligationCauseCode::*;
19 use hir::def_id::DefId;
20 use middle::free_region::FreeRegionMap;
21 use ty::subst::Substs;
22 use ty::{self, Ty, TyCtxt, TypeFoldable, ToPredicate};
23 use ty::error::{ExpectedFound, TypeError};
24 use infer::{InferCtxt};
28 use syntax_pos::{Span, DUMMY_SP};
30 pub use self::error_reporting::TraitErrorKey;
31 pub use self::coherence::orphan_check;
32 pub use self::coherence::overlapping_impls;
33 pub use self::coherence::OrphanCheckErr;
34 pub use self::fulfill::{FulfillmentContext, GlobalFulfilledPredicates, RegionObligation};
35 pub use self::project::MismatchedProjectionTypes;
36 pub use self::project::{normalize, normalize_projection_type, Normalized};
37 pub use self::project::{ProjectionCache, ProjectionCacheSnapshot, Reveal};
38 pub use self::object_safety::ObjectSafetyViolation;
39 pub use self::object_safety::MethodViolationCode;
40 pub use self::select::{EvaluationCache, SelectionContext, SelectionCache};
41 pub use self::specialize::{OverlapError, specialization_graph, specializes, translate_substs};
42 pub use self::specialize::{SpecializesCache, find_associated_item};
43 pub use self::util::elaborate_predicates;
44 pub use self::util::supertraits;
45 pub use self::util::Supertraits;
46 pub use self::util::supertrait_def_ids;
47 pub use self::util::SupertraitDefIds;
48 pub use self::util::transitive_bounds;
60 /// An `Obligation` represents some trait reference (e.g. `int:Eq`) for
61 /// which the vtable must be found. The process of finding a vtable is
62 /// called "resolving" the `Obligation`. This process consists of
63 /// either identifying an `impl` (e.g., `impl Eq for int`) that
64 /// provides the required vtable, or else finding a bound that is in
65 /// scope. The eventual result is usually a `Selection` (defined below).
66 #[derive(Clone, PartialEq, Eq)]
67 pub struct Obligation<'tcx, T> {
68 pub cause: ObligationCause<'tcx>,
69 pub recursion_depth: usize,
73 pub type PredicateObligation<'tcx> = Obligation<'tcx, ty::Predicate<'tcx>>;
74 pub type TraitObligation<'tcx> = Obligation<'tcx, ty::PolyTraitPredicate<'tcx>>;
76 /// Why did we incur this obligation? Used for error reporting.
77 #[derive(Clone, Debug, PartialEq, Eq)]
78 pub struct ObligationCause<'tcx> {
81 // The id of the fn body that triggered this obligation. This is
82 // used for region obligations to determine the precise
83 // environment in which the region obligation should be evaluated
84 // (in particular, closures can add new assumptions). See the
85 // field `region_obligations` of the `FulfillmentContext` for more
87 pub body_id: ast::NodeId,
89 pub code: ObligationCauseCode<'tcx>
92 #[derive(Clone, Debug, PartialEq, Eq)]
93 pub enum ObligationCauseCode<'tcx> {
94 /// Not well classified or should be obvious from span.
97 /// A slice or array is WF only if `T: Sized`
100 /// A tuple is WF only if its middle elements are Sized
103 /// This is the trait reference from the given projection
104 ProjectionWf(ty::ProjectionTy<'tcx>),
106 /// In an impl of trait X for type Y, type Y must
107 /// also implement all supertraits of X.
108 ItemObligation(DefId),
110 /// A type like `&'a T` is WF only if `T: 'a`.
111 ReferenceOutlivesReferent(Ty<'tcx>),
113 /// A type like `Box<Foo<'a> + 'b>` is WF only if `'b: 'a`.
114 ObjectTypeBound(Ty<'tcx>, &'tcx ty::Region),
116 /// Obligation incurred due to an object cast.
117 ObjectCastObligation(/* Object type */ Ty<'tcx>),
119 /// Various cases where expressions must be sized/copy/etc:
120 AssignmentLhsSized, // L = X implies that L is Sized
121 StructInitializerSized, // S { ... } must be Sized
122 VariableType(ast::NodeId), // Type of each variable must be Sized
123 ReturnType, // Return type must be Sized
124 RepeatVec, // [T,..n] --> T must be Copy
126 // Types of fields (other than the last) in a struct must be sized.
129 // Constant expressions must be sized.
132 // static items must have `Sync` type
135 BuiltinDerivedObligation(DerivedObligationCause<'tcx>),
137 ImplDerivedObligation(DerivedObligationCause<'tcx>),
139 // error derived when matching traits/impls; see ObligationCause for more details
140 CompareImplMethodObligation {
141 item_name: ast::Name,
142 impl_item_def_id: DefId,
143 trait_item_def_id: DefId,
144 lint_id: Option<ast::NodeId>,
147 // Checking that this expression can be assigned where it needs to be
148 // FIXME(eddyb) #11161 is the original Expr required?
151 // Computing common supertype in the arms of a match expression
152 MatchExpressionArm { arm_span: Span,
153 source: hir::MatchSource },
155 // Computing common supertype in an if expression
158 // Computing common supertype of an if expression with no else counter-part
159 IfExpressionWithNoElse,
164 // `main` has wrong type
167 // `start` has wrong type
170 // intrinsic has wrong type
176 // `return` with no expression
180 #[derive(Clone, Debug, PartialEq, Eq)]
181 pub struct DerivedObligationCause<'tcx> {
182 /// The trait reference of the parent obligation that led to the
183 /// current obligation. Note that only trait obligations lead to
184 /// derived obligations, so we just store the trait reference here
186 parent_trait_ref: ty::PolyTraitRef<'tcx>,
188 /// The parent trait had this cause
189 parent_code: Rc<ObligationCauseCode<'tcx>>
192 pub type Obligations<'tcx, O> = Vec<Obligation<'tcx, O>>;
193 pub type PredicateObligations<'tcx> = Vec<PredicateObligation<'tcx>>;
194 pub type TraitObligations<'tcx> = Vec<TraitObligation<'tcx>>;
196 pub type Selection<'tcx> = Vtable<'tcx, PredicateObligation<'tcx>>;
198 #[derive(Clone,Debug)]
199 pub enum SelectionError<'tcx> {
201 OutputTypeParameterMismatch(ty::PolyTraitRef<'tcx>,
202 ty::PolyTraitRef<'tcx>,
203 ty::error::TypeError<'tcx>),
204 TraitNotObjectSafe(DefId),
207 pub struct FulfillmentError<'tcx> {
208 pub obligation: PredicateObligation<'tcx>,
209 pub code: FulfillmentErrorCode<'tcx>
213 pub enum FulfillmentErrorCode<'tcx> {
214 CodeSelectionError(SelectionError<'tcx>),
215 CodeProjectionError(MismatchedProjectionTypes<'tcx>),
216 CodeSubtypeError(ExpectedFound<Ty<'tcx>>,
217 TypeError<'tcx>), // always comes from a SubtypePredicate
221 /// When performing resolution, it is typically the case that there
222 /// can be one of three outcomes:
224 /// - `Ok(Some(r))`: success occurred with result `r`
225 /// - `Ok(None)`: could not definitely determine anything, usually due
226 /// to inconclusive type inference.
227 /// - `Err(e)`: error `e` occurred
228 pub type SelectionResult<'tcx, T> = Result<Option<T>, SelectionError<'tcx>>;
230 /// Given the successful resolution of an obligation, the `Vtable`
231 /// indicates where the vtable comes from. Note that while we call this
232 /// a "vtable", it does not necessarily indicate dynamic dispatch at
233 /// runtime. `Vtable` instances just tell the compiler where to find
234 /// methods, but in generic code those methods are typically statically
235 /// dispatched -- only when an object is constructed is a `Vtable`
236 /// instance reified into an actual vtable.
238 /// For example, the vtable may be tied to a specific impl (case A),
239 /// or it may be relative to some bound that is in scope (case B).
243 /// impl<T:Clone> Clone<T> for Option<T> { ... } // Impl_1
244 /// impl<T:Clone> Clone<T> for Box<T> { ... } // Impl_2
245 /// impl Clone for int { ... } // Impl_3
247 /// fn foo<T:Clone>(concrete: Option<Box<int>>,
249 /// mixed: Option<T>) {
251 /// // Case A: Vtable points at a specific impl. Only possible when
252 /// // type is concretely known. If the impl itself has bounded
253 /// // type parameters, Vtable will carry resolutions for those as well:
254 /// concrete.clone(); // Vtable(Impl_1, [Vtable(Impl_2, [Vtable(Impl_3)])])
256 /// // Case B: Vtable must be provided by caller. This applies when
257 /// // type is a type parameter.
258 /// param.clone(); // VtableParam
260 /// // Case C: A mix of cases A and B.
261 /// mixed.clone(); // Vtable(Impl_1, [VtableParam])
265 /// ### The type parameter `N`
267 /// See explanation on `VtableImplData`.
269 pub enum Vtable<'tcx, N> {
270 /// Vtable identifying a particular impl.
271 VtableImpl(VtableImplData<'tcx, N>),
273 /// Vtable for default trait implementations
274 /// This carries the information and nested obligations with regards
275 /// to a default implementation for a trait `Trait`. The nested obligations
276 /// ensure the trait implementation holds for all the constituent types.
277 VtableDefaultImpl(VtableDefaultImplData<N>),
279 /// Successful resolution to an obligation provided by the caller
280 /// for some type parameter. The `Vec<N>` represents the
281 /// obligations incurred from normalizing the where-clause (if
285 /// Virtual calls through an object
286 VtableObject(VtableObjectData<'tcx, N>),
288 /// Successful resolution for a builtin trait.
289 VtableBuiltin(VtableBuiltinData<N>),
291 /// Vtable automatically generated for a closure. The def ID is the ID
292 /// of the closure expression. This is a `VtableImpl` in spirit, but the
293 /// impl is generated by the compiler and does not appear in the source.
294 VtableClosure(VtableClosureData<'tcx, N>),
296 /// Same as above, but for a fn pointer type with the given signature.
297 VtableFnPointer(VtableFnPointerData<'tcx, N>),
300 /// Identifies a particular impl in the source, along with a set of
301 /// substitutions from the impl's type/lifetime parameters. The
302 /// `nested` vector corresponds to the nested obligations attached to
303 /// the impl's type parameters.
305 /// The type parameter `N` indicates the type used for "nested
306 /// obligations" that are required by the impl. During type check, this
307 /// is `Obligation`, as one might expect. During trans, however, this
308 /// is `()`, because trans only requires a shallow resolution of an
309 /// impl, and nested obligations are satisfied later.
310 #[derive(Clone, PartialEq, Eq)]
311 pub struct VtableImplData<'tcx, N> {
312 pub impl_def_id: DefId,
313 pub substs: &'tcx Substs<'tcx>,
317 #[derive(Clone, PartialEq, Eq)]
318 pub struct VtableClosureData<'tcx, N> {
319 pub closure_def_id: DefId,
320 pub substs: ty::ClosureSubsts<'tcx>,
321 /// Nested obligations. This can be non-empty if the closure
322 /// signature contains associated types.
327 pub struct VtableDefaultImplData<N> {
328 pub trait_def_id: DefId,
333 pub struct VtableBuiltinData<N> {
337 /// A vtable for some object-safe trait `Foo` automatically derived
338 /// for the object type `Foo`.
339 #[derive(PartialEq,Eq,Clone)]
340 pub struct VtableObjectData<'tcx, N> {
341 /// `Foo` upcast to the obligation trait. This will be some supertrait of `Foo`.
342 pub upcast_trait_ref: ty::PolyTraitRef<'tcx>,
344 /// The vtable is formed by concatenating together the method lists of
345 /// the base object trait and all supertraits; this is the start of
346 /// `upcast_trait_ref`'s methods in that vtable.
347 pub vtable_base: usize,
352 #[derive(Clone, PartialEq, Eq)]
353 pub struct VtableFnPointerData<'tcx, N> {
354 pub fn_ty: ty::Ty<'tcx>,
358 /// Creates predicate obligations from the generic bounds.
359 pub fn predicates_for_generics<'tcx>(cause: ObligationCause<'tcx>,
360 generic_bounds: &ty::InstantiatedPredicates<'tcx>)
361 -> PredicateObligations<'tcx>
363 util::predicates_for_generics(cause, 0, generic_bounds)
366 /// Determines whether the type `ty` is known to meet `bound` and
367 /// returns true if so. Returns false if `ty` either does not meet
368 /// `bound` or is not known to meet bound (note that this is
369 /// conservative towards *no impl*, which is the opposite of the
370 /// `evaluate` methods).
371 pub fn type_known_to_meet_bound<'a, 'gcx, 'tcx>(infcx: &InferCtxt<'a, 'gcx, 'tcx>,
377 debug!("type_known_to_meet_bound(ty={:?}, bound={:?})",
379 infcx.tcx.item_path_str(def_id));
381 let trait_ref = ty::TraitRef {
383 substs: infcx.tcx.mk_substs_trait(ty, &[]),
385 let obligation = Obligation {
386 cause: ObligationCause::misc(span, ast::DUMMY_NODE_ID),
388 predicate: trait_ref.to_predicate(),
391 let result = SelectionContext::new(infcx)
392 .evaluate_obligation_conservatively(&obligation);
393 debug!("type_known_to_meet_ty={:?} bound={} => {:?}",
394 ty, infcx.tcx.item_path_str(def_id), result);
396 if result && (ty.has_infer_types() || ty.has_closure_types()) {
397 // Because of inference "guessing", selection can sometimes claim
398 // to succeed while the success requires a guess. To ensure
399 // this function's result remains infallible, we must confirm
400 // that guess. While imperfect, I believe this is sound.
402 let mut fulfill_cx = FulfillmentContext::new();
404 // We can use a dummy node-id here because we won't pay any mind
405 // to region obligations that arise (there shouldn't really be any
407 let cause = ObligationCause::misc(span, ast::DUMMY_NODE_ID);
409 fulfill_cx.register_bound(infcx, ty, def_id, cause);
411 // Note: we only assume something is `Copy` if we can
412 // *definitively* show that it implements `Copy`. Otherwise,
413 // assume it is move; linear is always ok.
414 match fulfill_cx.select_all_or_error(infcx) {
416 debug!("type_known_to_meet_bound: ty={:?} bound={} success",
418 infcx.tcx.item_path_str(def_id));
422 debug!("type_known_to_meet_bound: ty={:?} bound={} errors={:?}",
424 infcx.tcx.item_path_str(def_id),
434 // FIXME: this is gonna need to be removed ...
435 /// Normalizes the parameter environment, reporting errors if they occur.
436 pub fn normalize_param_env_or_error<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
437 unnormalized_env: ty::ParameterEnvironment<'tcx>,
438 cause: ObligationCause<'tcx>)
439 -> ty::ParameterEnvironment<'tcx>
441 // I'm not wild about reporting errors here; I'd prefer to
442 // have the errors get reported at a defined place (e.g.,
443 // during typeck). Instead I have all parameter
444 // environments, in effect, going through this function
445 // and hence potentially reporting errors. This ensurse of
446 // course that we never forget to normalize (the
447 // alternative seemed like it would involve a lot of
448 // manual invocations of this fn -- and then we'd have to
449 // deal with the errors at each of those sites).
451 // In any case, in practice, typeck constructs all the
452 // parameter environments once for every fn as it goes,
453 // and errors will get reported then; so after typeck we
454 // can be sure that no errors should occur.
456 let span = cause.span;
457 let body_id = cause.body_id;
459 debug!("normalize_param_env_or_error(unnormalized_env={:?})",
462 let predicates: Vec<_> =
463 util::elaborate_predicates(tcx, unnormalized_env.caller_bounds.clone())
464 .filter(|p| !p.is_global()) // (*)
467 // (*) Any predicate like `i32: Trait<u32>` or whatever doesn't
468 // need to be in the *environment* to be proven, so screen those
469 // out. This is important for the soundness of inter-fn
470 // caching. Note though that we should probably check that these
471 // predicates hold at the point where the environment is
472 // constructed, but I am not currently doing so out of laziness.
475 debug!("normalize_param_env_or_error: elaborated-predicates={:?}",
478 let elaborated_env = unnormalized_env.with_caller_bounds(predicates);
480 tcx.infer_ctxt(elaborated_env, Reveal::UserFacing).enter(|infcx| {
481 let predicates = match fully_normalize(&infcx, cause,
482 &infcx.parameter_environment.caller_bounds) {
483 Ok(predicates) => predicates,
485 infcx.report_fulfillment_errors(&errors);
486 // An unnormalized env is better than nothing.
487 return infcx.parameter_environment;
491 debug!("normalize_param_env_or_error: normalized predicates={:?}",
494 let free_regions = FreeRegionMap::new();
495 infcx.resolve_regions_and_report_errors(&free_regions, body_id);
496 let predicates = match infcx.fully_resolve(&predicates) {
497 Ok(predicates) => predicates,
499 // If we encounter a fixup error, it means that some type
500 // variable wound up unconstrained. I actually don't know
501 // if this can happen, and I certainly don't expect it to
502 // happen often, but if it did happen it probably
503 // represents a legitimate failure due to some kind of
504 // unconstrained variable, and it seems better not to ICE,
505 // all things considered.
506 tcx.sess.span_err(span, &fixup_err.to_string());
507 // An unnormalized env is better than nothing.
508 return infcx.parameter_environment;
512 let predicates = match tcx.lift_to_global(&predicates) {
513 Some(predicates) => predicates,
514 None => return infcx.parameter_environment
517 debug!("normalize_param_env_or_error: resolved predicates={:?}",
520 infcx.parameter_environment.with_caller_bounds(predicates)
524 pub fn fully_normalize<'a, 'gcx, 'tcx, T>(infcx: &InferCtxt<'a, 'gcx, 'tcx>,
525 cause: ObligationCause<'tcx>,
527 -> Result<T, Vec<FulfillmentError<'tcx>>>
528 where T : TypeFoldable<'tcx>
530 debug!("fully_normalize(value={:?})", value);
532 let mut selcx = &mut SelectionContext::new(infcx);
533 // FIXME (@jroesch) ISSUE 26721
534 // I'm not sure if this is a bug or not, needs further investigation.
535 // It appears that by reusing the fulfillment_cx here we incur more
536 // obligations and later trip an asssertion on regionck.rs line 337.
538 // The two possibilities I see is:
539 // - normalization is not actually fully happening and we
540 // have a bug else where
541 // - we are adding a duplicate bound into the list causing
542 // its size to change.
544 // I think we should probably land this refactor and then come
545 // back to this is a follow-up patch.
546 let mut fulfill_cx = FulfillmentContext::new();
548 let Normalized { value: normalized_value, obligations } =
549 project::normalize(selcx, cause, value);
550 debug!("fully_normalize: normalized_value={:?} obligations={:?}",
553 for obligation in obligations {
554 fulfill_cx.register_predicate_obligation(selcx.infcx(), obligation);
557 debug!("fully_normalize: select_all_or_error start");
558 match fulfill_cx.select_all_or_error(infcx) {
561 debug!("fully_normalize: error={:?}", e);
565 debug!("fully_normalize: select_all_or_error complete");
566 let resolved_value = infcx.resolve_type_vars_if_possible(&normalized_value);
567 debug!("fully_normalize: resolved_value={:?}", resolved_value);
571 /// Normalizes the predicates and checks whether they hold. If this
572 /// returns false, then either normalize encountered an error or one
573 /// of the predicates did not hold. Used when creating vtables to
574 /// check for unsatisfiable methods.
575 pub fn normalize_and_test_predicates<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
576 predicates: Vec<ty::Predicate<'tcx>>)
579 debug!("normalize_and_test_predicates(predicates={:?})",
582 tcx.infer_ctxt((), Reveal::All).enter(|infcx| {
583 let mut selcx = SelectionContext::new(&infcx);
584 let mut fulfill_cx = FulfillmentContext::new();
585 let cause = ObligationCause::dummy();
586 let Normalized { value: predicates, obligations } =
587 normalize(&mut selcx, cause.clone(), &predicates);
588 for obligation in obligations {
589 fulfill_cx.register_predicate_obligation(&infcx, obligation);
591 for predicate in predicates {
592 let obligation = Obligation::new(cause.clone(), predicate);
593 fulfill_cx.register_predicate_obligation(&infcx, obligation);
596 fulfill_cx.select_all_or_error(&infcx).is_ok()
600 /// Given a trait `trait_ref`, iterates the vtable entries
601 /// that come from `trait_ref`, including its supertraits.
602 #[inline] // FIXME(#35870) Avoid closures being unexported due to impl Trait.
603 pub fn get_vtable_methods<'a, 'tcx>(
604 tcx: TyCtxt<'a, 'tcx, 'tcx>,
605 trait_ref: ty::PolyTraitRef<'tcx>)
606 -> impl Iterator<Item=Option<(DefId, &'tcx Substs<'tcx>)>> + 'a
608 debug!("get_vtable_methods({:?})", trait_ref);
610 supertraits(tcx, trait_ref).flat_map(move |trait_ref| {
611 tcx.populate_implementations_for_trait_if_necessary(trait_ref.def_id());
613 let trait_methods = tcx.associated_items(trait_ref.def_id())
614 .filter(|item| item.kind == ty::AssociatedKind::Method);
616 // Now list each method's DefId and Substs (for within its trait).
617 // If the method can never be called from this object, produce None.
618 trait_methods.map(move |trait_method| {
619 debug!("get_vtable_methods: trait_method={:?}", trait_method);
620 let def_id = trait_method.def_id;
622 // Some methods cannot be called on an object; skip those.
623 if !tcx.is_vtable_safe_method(trait_ref.def_id(), &trait_method) {
624 debug!("get_vtable_methods: not vtable safe");
628 // the method may have some early-bound lifetimes, add
630 let substs = Substs::for_item(tcx, def_id,
631 |_, _| tcx.mk_region(ty::ReErased),
632 |def, _| trait_ref.substs().type_for_def(def));
634 // the trait type may have higher-ranked lifetimes in it;
635 // so erase them if they appear, so that we get the type
636 // at some particular call site
637 let substs = tcx.erase_late_bound_regions_and_normalize(&ty::Binder(substs));
639 // It's possible that the method relies on where clauses that
640 // do not hold for this particular set of type parameters.
641 // Note that this method could then never be called, so we
642 // do not want to try and trans it, in that case (see #23435).
643 let predicates = tcx.item_predicates(def_id).instantiate_own(tcx, substs);
644 if !normalize_and_test_predicates(tcx, predicates.predicates) {
645 debug!("get_vtable_methods: predicates do not hold");
649 Some((def_id, substs))
654 impl<'tcx,O> Obligation<'tcx,O> {
655 pub fn new(cause: ObligationCause<'tcx>,
657 -> Obligation<'tcx, O>
659 Obligation { cause: cause,
661 predicate: trait_ref }
664 fn with_depth(cause: ObligationCause<'tcx>,
665 recursion_depth: usize,
667 -> Obligation<'tcx, O>
669 Obligation { cause: cause,
670 recursion_depth: recursion_depth,
671 predicate: trait_ref }
674 pub fn misc(span: Span, body_id: ast::NodeId, trait_ref: O) -> Obligation<'tcx, O> {
675 Obligation::new(ObligationCause::misc(span, body_id), trait_ref)
678 pub fn with<P>(&self, value: P) -> Obligation<'tcx,P> {
679 Obligation { cause: self.cause.clone(),
680 recursion_depth: self.recursion_depth,
685 impl<'tcx> ObligationCause<'tcx> {
686 pub fn new(span: Span,
687 body_id: ast::NodeId,
688 code: ObligationCauseCode<'tcx>)
689 -> ObligationCause<'tcx> {
690 ObligationCause { span: span, body_id: body_id, code: code }
693 pub fn misc(span: Span, body_id: ast::NodeId) -> ObligationCause<'tcx> {
694 ObligationCause { span: span, body_id: body_id, code: MiscObligation }
697 pub fn dummy() -> ObligationCause<'tcx> {
698 ObligationCause { span: DUMMY_SP, body_id: ast::CRATE_NODE_ID, code: MiscObligation }
702 impl<'tcx, N> Vtable<'tcx, N> {
703 pub fn nested_obligations(self) -> Vec<N> {
705 VtableImpl(i) => i.nested,
707 VtableBuiltin(i) => i.nested,
708 VtableDefaultImpl(d) => d.nested,
709 VtableClosure(c) => c.nested,
710 VtableObject(d) => d.nested,
711 VtableFnPointer(d) => d.nested,
715 fn nested_obligations_mut(&mut self) -> &mut Vec<N> {
717 &mut VtableImpl(ref mut i) => &mut i.nested,
718 &mut VtableParam(ref mut n) => n,
719 &mut VtableBuiltin(ref mut i) => &mut i.nested,
720 &mut VtableDefaultImpl(ref mut d) => &mut d.nested,
721 &mut VtableClosure(ref mut c) => &mut c.nested,
722 &mut VtableObject(ref mut d) => &mut d.nested,
723 &mut VtableFnPointer(ref mut d) => &mut d.nested,
727 pub fn map<M, F>(self, f: F) -> Vtable<'tcx, M> where F: FnMut(N) -> M {
729 VtableImpl(i) => VtableImpl(VtableImplData {
730 impl_def_id: i.impl_def_id,
732 nested: i.nested.into_iter().map(f).collect(),
734 VtableParam(n) => VtableParam(n.into_iter().map(f).collect()),
735 VtableBuiltin(i) => VtableBuiltin(VtableBuiltinData {
736 nested: i.nested.into_iter().map(f).collect(),
738 VtableObject(o) => VtableObject(VtableObjectData {
739 upcast_trait_ref: o.upcast_trait_ref,
740 vtable_base: o.vtable_base,
741 nested: o.nested.into_iter().map(f).collect(),
743 VtableDefaultImpl(d) => VtableDefaultImpl(VtableDefaultImplData {
744 trait_def_id: d.trait_def_id,
745 nested: d.nested.into_iter().map(f).collect(),
747 VtableFnPointer(p) => VtableFnPointer(VtableFnPointerData {
749 nested: p.nested.into_iter().map(f).collect(),
751 VtableClosure(c) => VtableClosure(VtableClosureData {
752 closure_def_id: c.closure_def_id,
754 nested: c.nested.into_iter().map(f).collect(),
760 impl<'tcx> FulfillmentError<'tcx> {
761 fn new(obligation: PredicateObligation<'tcx>,
762 code: FulfillmentErrorCode<'tcx>)
763 -> FulfillmentError<'tcx>
765 FulfillmentError { obligation: obligation, code: code }
769 impl<'tcx> TraitObligation<'tcx> {
770 fn self_ty(&self) -> ty::Binder<Ty<'tcx>> {
771 ty::Binder(self.predicate.skip_binder().self_ty())