1 // Copyright 2012-2013 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 //! Generalized type relating mechanism. A type relation R relates a
12 //! pair of values (A, B). A and B are usually types or regions but
13 //! can be other things. Examples of type relations are subtyping,
14 //! type equality, etc.
16 use hir::def_id::DefId;
17 use middle::const_val::ConstVal;
18 use ty::subst::{Kind, UnpackedKind, Substs};
19 use ty::{self, Ty, TyCtxt, TypeFoldable};
20 use ty::error::{ExpectedFound, TypeError};
21 use mir::interpret::{GlobalId, Value, PrimVal};
22 use util::common::ErrorReported;
27 use rustc_data_structures::accumulate_vec::AccumulateVec;
29 pub type RelateResult<'tcx, T> = Result<T, TypeError<'tcx>>;
31 #[derive(Clone, Debug)]
33 ExistentialRegionBound, // relating an existential region bound
36 pub trait TypeRelation<'a, 'gcx: 'a+'tcx, 'tcx: 'a> : Sized {
37 fn tcx(&self) -> TyCtxt<'a, 'gcx, 'tcx>;
39 /// Returns a static string we can use for printouts.
40 fn tag(&self) -> &'static str;
42 /// Returns true if the value `a` is the "expected" type in the
43 /// relation. Just affects error messages.
44 fn a_is_expected(&self) -> bool;
46 fn with_cause<F,R>(&mut self, _cause: Cause, f: F) -> R
47 where F: FnOnce(&mut Self) -> R
52 /// Generic relation routine suitable for most anything.
53 fn relate<T: Relate<'tcx>>(&mut self, a: &T, b: &T) -> RelateResult<'tcx, T> {
54 Relate::relate(self, a, b)
57 /// Relate the two substitutions for the given item. The default
58 /// is to look up the variance for the item and proceed
60 fn relate_item_substs(&mut self,
62 a_subst: &'tcx Substs<'tcx>,
63 b_subst: &'tcx Substs<'tcx>)
64 -> RelateResult<'tcx, &'tcx Substs<'tcx>>
66 debug!("relate_item_substs(item_def_id={:?}, a_subst={:?}, b_subst={:?})",
71 let opt_variances = self.tcx().variances_of(item_def_id);
72 relate_substs(self, Some(&opt_variances), a_subst, b_subst)
75 /// Switch variance for the purpose of relating `a` and `b`.
76 fn relate_with_variance<T: Relate<'tcx>>(&mut self,
77 variance: ty::Variance,
80 -> RelateResult<'tcx, T>;
82 // Overrideable relations. You shouldn't typically call these
83 // directly, instead call `relate()`, which in turn calls
84 // these. This is both more uniform but also allows us to add
85 // additional hooks for other types in the future if needed
86 // without making older code, which called `relate`, obsolete.
88 fn tys(&mut self, a: Ty<'tcx>, b: Ty<'tcx>)
89 -> RelateResult<'tcx, Ty<'tcx>>;
91 fn regions(&mut self, a: ty::Region<'tcx>, b: ty::Region<'tcx>)
92 -> RelateResult<'tcx, ty::Region<'tcx>>;
94 fn binders<T>(&mut self, a: &ty::Binder<T>, b: &ty::Binder<T>)
95 -> RelateResult<'tcx, ty::Binder<T>>
96 where T: Relate<'tcx>;
99 pub trait Relate<'tcx>: TypeFoldable<'tcx> {
100 fn relate<'a, 'gcx, R>(relation: &mut R, a: &Self, b: &Self)
101 -> RelateResult<'tcx, Self>
102 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a;
105 ///////////////////////////////////////////////////////////////////////////
108 impl<'tcx> Relate<'tcx> for ty::TypeAndMut<'tcx> {
109 fn relate<'a, 'gcx, R>(relation: &mut R,
110 a: &ty::TypeAndMut<'tcx>,
111 b: &ty::TypeAndMut<'tcx>)
112 -> RelateResult<'tcx, ty::TypeAndMut<'tcx>>
113 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
115 debug!("{}.mts({:?}, {:?})",
119 if a.mutbl != b.mutbl {
120 Err(TypeError::Mutability)
123 let variance = match mutbl {
124 ast::Mutability::MutImmutable => ty::Covariant,
125 ast::Mutability::MutMutable => ty::Invariant,
127 let ty = relation.relate_with_variance(variance, &a.ty, &b.ty)?;
128 Ok(ty::TypeAndMut {ty: ty, mutbl: mutbl})
133 pub fn relate_substs<'a, 'gcx, 'tcx, R>(relation: &mut R,
134 variances: Option<&Vec<ty::Variance>>,
135 a_subst: &'tcx Substs<'tcx>,
136 b_subst: &'tcx Substs<'tcx>)
137 -> RelateResult<'tcx, &'tcx Substs<'tcx>>
138 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
140 let tcx = relation.tcx();
142 let params = a_subst.iter().zip(b_subst).enumerate().map(|(i, (a, b))| {
143 let variance = variances.map_or(ty::Invariant, |v| v[i]);
144 relation.relate_with_variance(variance, a, b)
147 Ok(tcx.mk_substs(params)?)
150 impl<'tcx> Relate<'tcx> for ty::FnSig<'tcx> {
151 fn relate<'a, 'gcx, R>(relation: &mut R,
154 -> RelateResult<'tcx, ty::FnSig<'tcx>>
155 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
157 if a.variadic != b.variadic {
158 return Err(TypeError::VariadicMismatch(
159 expected_found(relation, &a.variadic, &b.variadic)));
161 let unsafety = relation.relate(&a.unsafety, &b.unsafety)?;
162 let abi = relation.relate(&a.abi, &b.abi)?;
164 if a.inputs().len() != b.inputs().len() {
165 return Err(TypeError::ArgCount);
168 let inputs_and_output = a.inputs().iter().cloned()
169 .zip(b.inputs().iter().cloned())
171 .chain(iter::once(((a.output(), b.output()), true)))
172 .map(|((a, b), is_output)| {
174 relation.relate(&a, &b)
176 relation.relate_with_variance(ty::Contravariant, &a, &b)
178 }).collect::<Result<AccumulateVec<[_; 8]>, _>>()?;
180 inputs_and_output: relation.tcx().intern_type_list(&inputs_and_output),
181 variadic: a.variadic,
188 impl<'tcx> Relate<'tcx> for ast::Unsafety {
189 fn relate<'a, 'gcx, R>(relation: &mut R,
192 -> RelateResult<'tcx, ast::Unsafety>
193 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
196 Err(TypeError::UnsafetyMismatch(expected_found(relation, a, b)))
203 impl<'tcx> Relate<'tcx> for abi::Abi {
204 fn relate<'a, 'gcx, R>(relation: &mut R,
207 -> RelateResult<'tcx, abi::Abi>
208 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
213 Err(TypeError::AbiMismatch(expected_found(relation, a, b)))
218 impl<'tcx> Relate<'tcx> for ty::ProjectionTy<'tcx> {
219 fn relate<'a, 'gcx, R>(relation: &mut R,
220 a: &ty::ProjectionTy<'tcx>,
221 b: &ty::ProjectionTy<'tcx>)
222 -> RelateResult<'tcx, ty::ProjectionTy<'tcx>>
223 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
225 if a.item_def_id != b.item_def_id {
226 Err(TypeError::ProjectionMismatched(
227 expected_found(relation, &a.item_def_id, &b.item_def_id)))
229 let substs = relation.relate(&a.substs, &b.substs)?;
230 Ok(ty::ProjectionTy {
231 item_def_id: a.item_def_id,
238 impl<'tcx> Relate<'tcx> for ty::ExistentialProjection<'tcx> {
239 fn relate<'a, 'gcx, R>(relation: &mut R,
240 a: &ty::ExistentialProjection<'tcx>,
241 b: &ty::ExistentialProjection<'tcx>)
242 -> RelateResult<'tcx, ty::ExistentialProjection<'tcx>>
243 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
245 if a.item_def_id != b.item_def_id {
246 Err(TypeError::ProjectionMismatched(
247 expected_found(relation, &a.item_def_id, &b.item_def_id)))
249 let ty = relation.relate(&a.ty, &b.ty)?;
250 let substs = relation.relate(&a.substs, &b.substs)?;
251 Ok(ty::ExistentialProjection {
252 item_def_id: a.item_def_id,
260 impl<'tcx> Relate<'tcx> for Vec<ty::PolyExistentialProjection<'tcx>> {
261 fn relate<'a, 'gcx, R>(relation: &mut R,
262 a: &Vec<ty::PolyExistentialProjection<'tcx>>,
263 b: &Vec<ty::PolyExistentialProjection<'tcx>>)
264 -> RelateResult<'tcx, Vec<ty::PolyExistentialProjection<'tcx>>>
265 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
267 // To be compatible, `a` and `b` must be for precisely the
268 // same set of traits and item names. We always require that
269 // projection bounds lists are sorted by trait-def-id and item-name,
270 // so we can just iterate through the lists pairwise, so long as they are the
272 if a.len() != b.len() {
273 Err(TypeError::ProjectionBoundsLength(expected_found(relation, &a.len(), &b.len())))
276 .map(|(a, b)| relation.relate(a, b))
282 impl<'tcx> Relate<'tcx> for ty::TraitRef<'tcx> {
283 fn relate<'a, 'gcx, R>(relation: &mut R,
284 a: &ty::TraitRef<'tcx>,
285 b: &ty::TraitRef<'tcx>)
286 -> RelateResult<'tcx, ty::TraitRef<'tcx>>
287 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
289 // Different traits cannot be related
290 if a.def_id != b.def_id {
291 Err(TypeError::Traits(expected_found(relation, &a.def_id, &b.def_id)))
293 let substs = relate_substs(relation, None, a.substs, b.substs)?;
294 Ok(ty::TraitRef { def_id: a.def_id, substs: substs })
299 impl<'tcx> Relate<'tcx> for ty::ExistentialTraitRef<'tcx> {
300 fn relate<'a, 'gcx, R>(relation: &mut R,
301 a: &ty::ExistentialTraitRef<'tcx>,
302 b: &ty::ExistentialTraitRef<'tcx>)
303 -> RelateResult<'tcx, ty::ExistentialTraitRef<'tcx>>
304 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
306 // Different traits cannot be related
307 if a.def_id != b.def_id {
308 Err(TypeError::Traits(expected_found(relation, &a.def_id, &b.def_id)))
310 let substs = relate_substs(relation, None, a.substs, b.substs)?;
311 Ok(ty::ExistentialTraitRef { def_id: a.def_id, substs: substs })
316 #[derive(Debug, Clone)]
317 struct GeneratorWitness<'tcx>(&'tcx ty::Slice<Ty<'tcx>>);
319 TupleStructTypeFoldableImpl! {
320 impl<'tcx> TypeFoldable<'tcx> for GeneratorWitness<'tcx> {
325 impl<'tcx> Relate<'tcx> for GeneratorWitness<'tcx> {
326 fn relate<'a, 'gcx, R>(relation: &mut R,
327 a: &GeneratorWitness<'tcx>,
328 b: &GeneratorWitness<'tcx>)
329 -> RelateResult<'tcx, GeneratorWitness<'tcx>>
330 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
332 assert!(a.0.len() == b.0.len());
333 let tcx = relation.tcx();
334 let types = tcx.mk_type_list(a.0.iter().zip(b.0).map(|(a, b)| relation.relate(a, b)))?;
335 Ok(GeneratorWitness(types))
339 impl<'tcx> Relate<'tcx> for Ty<'tcx> {
340 fn relate<'a, 'gcx, R>(relation: &mut R,
343 -> RelateResult<'tcx, Ty<'tcx>>
344 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
350 /// The main "type relation" routine. Note that this does not handle
351 /// inference artifacts, so you should filter those out before calling
353 pub fn super_relate_tys<'a, 'gcx, 'tcx, R>(relation: &mut R,
356 -> RelateResult<'tcx, Ty<'tcx>>
357 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
359 let tcx = relation.tcx();
362 debug!("super_tys: a_sty={:?} b_sty={:?}", a_sty, b_sty);
363 match (a_sty, b_sty) {
364 (&ty::TyInfer(_), _) |
365 (_, &ty::TyInfer(_)) =>
367 // The caller should handle these cases!
368 bug!("var types encountered in super_relate_tys")
371 (&ty::TyError, _) | (_, &ty::TyError) =>
380 (&ty::TyUint(_), _) |
381 (&ty::TyFloat(_), _) |
388 (&ty::TyParam(ref a_p), &ty::TyParam(ref b_p))
389 if a_p.idx == b_p.idx =>
394 (&ty::TyAdt(a_def, a_substs), &ty::TyAdt(b_def, b_substs))
397 let substs = relation.relate_item_substs(a_def.did, a_substs, b_substs)?;
398 Ok(tcx.mk_adt(a_def, substs))
401 (&ty::TyForeign(a_id), &ty::TyForeign(b_id))
404 Ok(tcx.mk_foreign(a_id))
407 (&ty::TyDynamic(ref a_obj, ref a_region), &ty::TyDynamic(ref b_obj, ref b_region)) => {
408 let region_bound = relation.with_cause(Cause::ExistentialRegionBound,
410 relation.relate_with_variance(
415 Ok(tcx.mk_dynamic(relation.relate(a_obj, b_obj)?, region_bound))
418 (&ty::TyGenerator(a_id, a_substs, a_interior),
419 &ty::TyGenerator(b_id, b_substs, b_interior))
422 // All TyGenerator types with the same id represent
423 // the (anonymous) type of the same generator expression. So
424 // all of their regions should be equated.
425 let substs = relation.relate(&a_substs, &b_substs)?;
426 let interior = relation.relate(&a_interior, &b_interior)?;
427 Ok(tcx.mk_generator(a_id, substs, interior))
430 (&ty::TyGeneratorWitness(a_types), &ty::TyGeneratorWitness(b_types)) =>
432 // Wrap our types with a temporary GeneratorWitness struct
433 // inside the binder so we can related them
434 let a_types = ty::Binder(GeneratorWitness(*a_types.skip_binder()));
435 let b_types = ty::Binder(GeneratorWitness(*b_types.skip_binder()));
436 // Then remove the GeneratorWitness for the result
437 let types = ty::Binder(relation.relate(&a_types, &b_types)?.skip_binder().0);
438 Ok(tcx.mk_generator_witness(types))
441 (&ty::TyClosure(a_id, a_substs),
442 &ty::TyClosure(b_id, b_substs))
445 // All TyClosure types with the same id represent
446 // the (anonymous) type of the same closure expression. So
447 // all of their regions should be equated.
448 let substs = relation.relate(&a_substs, &b_substs)?;
449 Ok(tcx.mk_closure_from_closure_substs(a_id, substs))
452 (&ty::TyRawPtr(ref a_mt), &ty::TyRawPtr(ref b_mt)) =>
454 let mt = relation.relate(a_mt, b_mt)?;
458 (&ty::TyRef(a_r, ref a_mt), &ty::TyRef(b_r, ref b_mt)) =>
460 let r = relation.relate_with_variance(ty::Contravariant, &a_r, &b_r)?;
461 let mt = relation.relate(a_mt, b_mt)?;
462 Ok(tcx.mk_ref(r, mt))
465 (&ty::TyArray(a_t, sz_a), &ty::TyArray(b_t, sz_b)) =>
467 let t = relation.relate(&a_t, &b_t)?;
468 assert_eq!(sz_a.ty, tcx.types.usize);
469 assert_eq!(sz_b.ty, tcx.types.usize);
470 let to_u64 = |x: &'tcx ty::Const<'tcx>| -> Result<u64, ErrorReported> {
472 ConstVal::Value(Value::ByVal(prim)) => Ok(prim.to_u64().unwrap()),
473 ConstVal::Unevaluated(def_id, substs) => {
474 // FIXME(eddyb) get the right param_env.
475 let param_env = ty::ParamEnv::empty();
476 match tcx.lift_to_global(&substs) {
478 let instance = ty::Instance::resolve(
484 if let Some(instance) = instance {
489 match tcx.const_eval(param_env.and(cid)) {
491 val: ConstVal::Value(Value::ByVal(PrimVal::Bytes(b))),
494 assert_eq!(b as u64 as u128, b);
503 tcx.sess.delay_span_bug(tcx.def_span(def_id),
504 "array length could not be evaluated");
507 _ => bug!("arrays should not have {:?} as length", x)
510 match (to_u64(sz_a), to_u64(sz_b)) {
511 (Ok(sz_a_u64), Ok(sz_b_u64)) => {
512 if sz_a_u64 == sz_b_u64 {
513 Ok(tcx.mk_ty(ty::TyArray(t, sz_a)))
515 Err(TypeError::FixedArraySize(
516 expected_found(relation, &sz_a_u64, &sz_b_u64)))
519 // We reported an error or will ICE, so we can return TyError.
520 (Err(ErrorReported), _) | (_, Err(ErrorReported)) => {
526 (&ty::TySlice(a_t), &ty::TySlice(b_t)) =>
528 let t = relation.relate(&a_t, &b_t)?;
532 (&ty::TyTuple(as_, a_defaulted), &ty::TyTuple(bs, b_defaulted)) =>
534 if as_.len() == bs.len() {
535 let defaulted = a_defaulted || b_defaulted;
536 Ok(tcx.mk_tup(as_.iter().zip(bs).map(|(a, b)| relation.relate(a, b)), defaulted)?)
537 } else if !(as_.is_empty() || bs.is_empty()) {
538 Err(TypeError::TupleSize(
539 expected_found(relation, &as_.len(), &bs.len())))
541 Err(TypeError::Sorts(expected_found(relation, &a, &b)))
545 (&ty::TyFnDef(a_def_id, a_substs), &ty::TyFnDef(b_def_id, b_substs))
546 if a_def_id == b_def_id =>
548 let substs = relation.relate_item_substs(a_def_id, a_substs, b_substs)?;
549 Ok(tcx.mk_fn_def(a_def_id, substs))
552 (&ty::TyFnPtr(a_fty), &ty::TyFnPtr(b_fty)) =>
554 let fty = relation.relate(&a_fty, &b_fty)?;
555 Ok(tcx.mk_fn_ptr(fty))
558 (&ty::TyProjection(ref a_data), &ty::TyProjection(ref b_data)) =>
560 let projection_ty = relation.relate(a_data, b_data)?;
561 Ok(tcx.mk_projection(projection_ty.item_def_id, projection_ty.substs))
564 (&ty::TyAnon(a_def_id, a_substs), &ty::TyAnon(b_def_id, b_substs))
565 if a_def_id == b_def_id =>
567 let substs = relate_substs(relation, None, a_substs, b_substs)?;
568 Ok(tcx.mk_anon(a_def_id, substs))
573 Err(TypeError::Sorts(expected_found(relation, &a, &b)))
578 impl<'tcx> Relate<'tcx> for &'tcx ty::Slice<ty::ExistentialPredicate<'tcx>> {
579 fn relate<'a, 'gcx, R>(relation: &mut R,
582 -> RelateResult<'tcx, Self>
583 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a {
585 if a.len() != b.len() {
586 return Err(TypeError::ExistentialMismatch(expected_found(relation, a, b)));
589 let tcx = relation.tcx();
590 let v = a.iter().zip(b.iter()).map(|(ep_a, ep_b)| {
591 use ty::ExistentialPredicate::*;
592 match (*ep_a, *ep_b) {
593 (Trait(ref a), Trait(ref b)) => Ok(Trait(relation.relate(a, b)?)),
594 (Projection(ref a), Projection(ref b)) => Ok(Projection(relation.relate(a, b)?)),
595 (AutoTrait(ref a), AutoTrait(ref b)) if a == b => Ok(AutoTrait(*a)),
596 _ => Err(TypeError::ExistentialMismatch(expected_found(relation, a, b)))
599 Ok(tcx.mk_existential_predicates(v)?)
603 impl<'tcx> Relate<'tcx> for ty::ClosureSubsts<'tcx> {
604 fn relate<'a, 'gcx, R>(relation: &mut R,
605 a: &ty::ClosureSubsts<'tcx>,
606 b: &ty::ClosureSubsts<'tcx>)
607 -> RelateResult<'tcx, ty::ClosureSubsts<'tcx>>
608 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
610 let substs = relate_substs(relation, None, a.substs, b.substs)?;
611 Ok(ty::ClosureSubsts { substs: substs })
615 impl<'tcx> Relate<'tcx> for ty::GeneratorInterior<'tcx> {
616 fn relate<'a, 'gcx, R>(relation: &mut R,
617 a: &ty::GeneratorInterior<'tcx>,
618 b: &ty::GeneratorInterior<'tcx>)
619 -> RelateResult<'tcx, ty::GeneratorInterior<'tcx>>
620 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
622 assert_eq!(a.movable, b.movable);
623 let witness = relation.relate(&a.witness, &b.witness)?;
624 Ok(ty::GeneratorInterior { witness, movable: a.movable })
628 impl<'tcx> Relate<'tcx> for &'tcx Substs<'tcx> {
629 fn relate<'a, 'gcx, R>(relation: &mut R,
630 a: &&'tcx Substs<'tcx>,
631 b: &&'tcx Substs<'tcx>)
632 -> RelateResult<'tcx, &'tcx Substs<'tcx>>
633 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
635 relate_substs(relation, None, a, b)
639 impl<'tcx> Relate<'tcx> for ty::Region<'tcx> {
640 fn relate<'a, 'gcx, R>(relation: &mut R,
641 a: &ty::Region<'tcx>,
642 b: &ty::Region<'tcx>)
643 -> RelateResult<'tcx, ty::Region<'tcx>>
644 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
646 relation.regions(*a, *b)
650 impl<'tcx, T: Relate<'tcx>> Relate<'tcx> for ty::Binder<T> {
651 fn relate<'a, 'gcx, R>(relation: &mut R,
654 -> RelateResult<'tcx, ty::Binder<T>>
655 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
657 relation.binders(a, b)
661 impl<'tcx, T: Relate<'tcx>> Relate<'tcx> for Rc<T> {
662 fn relate<'a, 'gcx, R>(relation: &mut R,
665 -> RelateResult<'tcx, Rc<T>>
666 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
670 Ok(Rc::new(relation.relate(a, b)?))
674 impl<'tcx, T: Relate<'tcx>> Relate<'tcx> for Box<T> {
675 fn relate<'a, 'gcx, R>(relation: &mut R,
678 -> RelateResult<'tcx, Box<T>>
679 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
683 Ok(Box::new(relation.relate(a, b)?))
687 impl<'tcx> Relate<'tcx> for Kind<'tcx> {
688 fn relate<'a, 'gcx, R>(
692 ) -> RelateResult<'tcx, Kind<'tcx>>
694 R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a,
696 match (a.unpack(), b.unpack()) {
697 (UnpackedKind::Lifetime(a_lt), UnpackedKind::Lifetime(b_lt)) => {
698 Ok(relation.relate(&a_lt, &b_lt)?.into())
700 (UnpackedKind::Type(a_ty), UnpackedKind::Type(b_ty)) => {
701 Ok(relation.relate(&a_ty, &b_ty)?.into())
703 (UnpackedKind::Lifetime(_), _) | (UnpackedKind::Type(_), _) => bug!()
708 ///////////////////////////////////////////////////////////////////////////
711 pub fn expected_found<'a, 'gcx, 'tcx, R, T>(relation: &mut R,
715 where R: TypeRelation<'a, 'gcx, 'tcx>, T: Clone, 'gcx: 'a+'tcx, 'tcx: 'a
717 expected_found_bool(relation.a_is_expected(), a, b)
720 pub fn expected_found_bool<T>(a_is_expected: bool,
729 ExpectedFound {expected: a, found: b}
731 ExpectedFound {expected: b, found: a}