1 //! Generalized type relating mechanism.
3 //! A type relation `R` relates a pair of values `(A, B)`. `A and B` are usually
4 //! types or regions but can be other things. Examples of type relations are
5 //! subtyping, type equality, etc.
7 use crate::hir::def_id::DefId;
8 use crate::ty::subst::{Kind, UnpackedKind, SubstsRef};
9 use crate::ty::{self, Ty, TyCtxt, TypeFoldable};
10 use crate::ty::error::{ExpectedFound, TypeError};
11 use crate::mir::interpret::{GlobalId, ConstValue};
12 use crate::util::common::ErrorReported;
13 use syntax_pos::DUMMY_SP;
16 use rustc_target::spec::abi;
17 use crate::hir as ast;
20 pub type RelateResult<'tcx, T> = Result<T, TypeError<'tcx>>;
22 #[derive(Clone, Debug)]
24 ExistentialRegionBound, // relating an existential region bound
27 pub trait TypeRelation<'a, 'gcx: 'a+'tcx, 'tcx: 'a> : Sized {
28 fn tcx(&self) -> TyCtxt<'a, 'gcx, 'tcx>;
30 /// Returns a static string we can use for printouts.
31 fn tag(&self) -> &'static str;
33 /// Returns `true` if the value `a` is the "expected" type in the
34 /// relation. Just affects error messages.
35 fn a_is_expected(&self) -> bool;
37 fn with_cause<F,R>(&mut self, _cause: Cause, f: F) -> R
38 where F: FnOnce(&mut Self) -> R
43 /// Generic relation routine suitable for most anything.
44 fn relate<T: Relate<'tcx>>(&mut self, a: &T, b: &T) -> RelateResult<'tcx, T> {
45 Relate::relate(self, a, b)
48 /// Relate the two substitutions for the given item. The default
49 /// is to look up the variance for the item and proceed
51 fn relate_item_substs(&mut self,
53 a_subst: SubstsRef<'tcx>,
54 b_subst: SubstsRef<'tcx>)
55 -> RelateResult<'tcx, SubstsRef<'tcx>>
57 debug!("relate_item_substs(item_def_id={:?}, a_subst={:?}, b_subst={:?})",
62 let opt_variances = self.tcx().variances_of(item_def_id);
63 relate_substs(self, Some(opt_variances), a_subst, b_subst)
66 /// Switch variance for the purpose of relating `a` and `b`.
67 fn relate_with_variance<T: Relate<'tcx>>(&mut self,
68 variance: ty::Variance,
71 -> RelateResult<'tcx, T>;
73 // Overrideable relations. You shouldn't typically call these
74 // directly, instead call `relate()`, which in turn calls
75 // these. This is both more uniform but also allows us to add
76 // additional hooks for other types in the future if needed
77 // without making older code, which called `relate`, obsolete.
79 fn tys(&mut self, a: Ty<'tcx>, b: Ty<'tcx>) -> RelateResult<'tcx, Ty<'tcx>>;
85 ) -> RelateResult<'tcx, ty::Region<'tcx>>;
89 a: &'tcx ty::LazyConst<'tcx>,
90 b: &'tcx ty::LazyConst<'tcx>
91 ) -> RelateResult<'tcx, &'tcx ty::LazyConst<'tcx>>;
93 fn binders<T>(&mut self, a: &ty::Binder<T>, b: &ty::Binder<T>)
94 -> RelateResult<'tcx, ty::Binder<T>>
95 where T: Relate<'tcx>;
98 pub trait Relate<'tcx>: TypeFoldable<'tcx> {
99 fn relate<'a, 'gcx, R>(relation: &mut R, a: &Self, b: &Self)
100 -> RelateResult<'tcx, Self>
101 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a;
104 ///////////////////////////////////////////////////////////////////////////
107 impl<'tcx> Relate<'tcx> for ty::TypeAndMut<'tcx> {
108 fn relate<'a, 'gcx, R>(relation: &mut R,
109 a: &ty::TypeAndMut<'tcx>,
110 b: &ty::TypeAndMut<'tcx>)
111 -> RelateResult<'tcx, ty::TypeAndMut<'tcx>>
112 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
114 debug!("{}.mts({:?}, {:?})",
118 if a.mutbl != b.mutbl {
119 Err(TypeError::Mutability)
122 let variance = match mutbl {
123 ast::Mutability::MutImmutable => ty::Covariant,
124 ast::Mutability::MutMutable => ty::Invariant,
126 let ty = relation.relate_with_variance(variance, &a.ty, &b.ty)?;
127 Ok(ty::TypeAndMut {ty: ty, mutbl: mutbl})
132 pub fn relate_substs<'a, 'gcx, 'tcx, R>(relation: &mut R,
133 variances: Option<&[ty::Variance]>,
134 a_subst: SubstsRef<'tcx>,
135 b_subst: SubstsRef<'tcx>)
136 -> RelateResult<'tcx, SubstsRef<'tcx>>
137 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
139 let tcx = relation.tcx();
141 let params = a_subst.iter().zip(b_subst).enumerate().map(|(i, (a, b))| {
142 let variance = variances.map_or(ty::Invariant, |v| v[i]);
143 relation.relate_with_variance(variance, a, b)
146 Ok(tcx.mk_substs(params)?)
149 impl<'tcx> Relate<'tcx> for ty::FnSig<'tcx> {
150 fn relate<'a, 'gcx, R>(relation: &mut R,
153 -> RelateResult<'tcx, ty::FnSig<'tcx>>
154 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
156 let tcx = relation.tcx();
158 if a.c_variadic != b.c_variadic {
159 return Err(TypeError::VariadicMismatch(
160 expected_found(relation, &a.c_variadic, &b.c_variadic)));
162 let unsafety = relation.relate(&a.unsafety, &b.unsafety)?;
163 let abi = relation.relate(&a.abi, &b.abi)?;
165 if a.inputs().len() != b.inputs().len() {
166 return Err(TypeError::ArgCount);
169 let inputs_and_output = a.inputs().iter().cloned()
170 .zip(b.inputs().iter().cloned())
172 .chain(iter::once(((a.output(), b.output()), true)))
173 .map(|((a, b), is_output)| {
175 relation.relate(&a, &b)
177 relation.relate_with_variance(ty::Contravariant, &a, &b)
181 inputs_and_output: tcx.mk_type_list(inputs_and_output)?,
182 c_variadic: a.c_variadic,
189 impl<'tcx> Relate<'tcx> for ast::Unsafety {
190 fn relate<'a, 'gcx, R>(relation: &mut R,
193 -> RelateResult<'tcx, ast::Unsafety>
194 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
197 Err(TypeError::UnsafetyMismatch(expected_found(relation, a, b)))
204 impl<'tcx> Relate<'tcx> for abi::Abi {
205 fn relate<'a, 'gcx, R>(relation: &mut R,
208 -> RelateResult<'tcx, abi::Abi>
209 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
214 Err(TypeError::AbiMismatch(expected_found(relation, a, b)))
219 impl<'tcx> Relate<'tcx> for ty::ProjectionTy<'tcx> {
220 fn relate<'a, 'gcx, R>(relation: &mut R,
221 a: &ty::ProjectionTy<'tcx>,
222 b: &ty::ProjectionTy<'tcx>)
223 -> RelateResult<'tcx, ty::ProjectionTy<'tcx>>
224 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
226 if a.item_def_id != b.item_def_id {
227 Err(TypeError::ProjectionMismatched(
228 expected_found(relation, &a.item_def_id, &b.item_def_id)))
230 let substs = relation.relate(&a.substs, &b.substs)?;
231 Ok(ty::ProjectionTy {
232 item_def_id: a.item_def_id,
239 impl<'tcx> Relate<'tcx> for ty::ExistentialProjection<'tcx> {
240 fn relate<'a, 'gcx, R>(relation: &mut R,
241 a: &ty::ExistentialProjection<'tcx>,
242 b: &ty::ExistentialProjection<'tcx>)
243 -> RelateResult<'tcx, ty::ExistentialProjection<'tcx>>
244 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
246 if a.item_def_id != b.item_def_id {
247 Err(TypeError::ProjectionMismatched(
248 expected_found(relation, &a.item_def_id, &b.item_def_id)))
250 let ty = relation.relate(&a.ty, &b.ty)?;
251 let substs = relation.relate(&a.substs, &b.substs)?;
252 Ok(ty::ExistentialProjection {
253 item_def_id: a.item_def_id,
261 impl<'tcx> Relate<'tcx> for Vec<ty::PolyExistentialProjection<'tcx>> {
262 fn relate<'a, 'gcx, R>(relation: &mut R,
263 a: &Vec<ty::PolyExistentialProjection<'tcx>>,
264 b: &Vec<ty::PolyExistentialProjection<'tcx>>)
265 -> RelateResult<'tcx, Vec<ty::PolyExistentialProjection<'tcx>>>
266 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
268 // To be compatible, `a` and `b` must be for precisely the
269 // same set of traits and item names. We always require that
270 // projection bounds lists are sorted by trait-def-id and item-name,
271 // so we can just iterate through the lists pairwise, so long as they are the
273 if a.len() != b.len() {
274 Err(TypeError::ProjectionBoundsLength(expected_found(relation, &a.len(), &b.len())))
278 .map(|(a, b)| relation.relate(a, b))
284 impl<'tcx> Relate<'tcx> for ty::TraitRef<'tcx> {
285 fn relate<'a, 'gcx, R>(relation: &mut R,
286 a: &ty::TraitRef<'tcx>,
287 b: &ty::TraitRef<'tcx>)
288 -> RelateResult<'tcx, ty::TraitRef<'tcx>>
289 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
291 // Different traits cannot be related
292 if a.def_id != b.def_id {
293 Err(TypeError::Traits(expected_found(relation, &a.def_id, &b.def_id)))
295 let substs = relate_substs(relation, None, a.substs, b.substs)?;
296 Ok(ty::TraitRef { def_id: a.def_id, substs: substs })
301 impl<'tcx> Relate<'tcx> for ty::ExistentialTraitRef<'tcx> {
302 fn relate<'a, 'gcx, R>(relation: &mut R,
303 a: &ty::ExistentialTraitRef<'tcx>,
304 b: &ty::ExistentialTraitRef<'tcx>)
305 -> RelateResult<'tcx, ty::ExistentialTraitRef<'tcx>>
306 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
308 // Different traits cannot be related
309 if a.def_id != b.def_id {
310 Err(TypeError::Traits(expected_found(relation, &a.def_id, &b.def_id)))
312 let substs = relate_substs(relation, None, a.substs, b.substs)?;
313 Ok(ty::ExistentialTraitRef { def_id: a.def_id, substs: substs })
318 #[derive(Debug, Clone)]
319 struct GeneratorWitness<'tcx>(&'tcx ty::List<Ty<'tcx>>);
321 TupleStructTypeFoldableImpl! {
322 impl<'tcx> TypeFoldable<'tcx> for GeneratorWitness<'tcx> {
327 impl<'tcx> Relate<'tcx> for GeneratorWitness<'tcx> {
328 fn relate<'a, 'gcx, R>(relation: &mut R,
329 a: &GeneratorWitness<'tcx>,
330 b: &GeneratorWitness<'tcx>)
331 -> RelateResult<'tcx, GeneratorWitness<'tcx>>
332 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
334 assert_eq!(a.0.len(), b.0.len());
335 let tcx = relation.tcx();
336 let types = tcx.mk_type_list(a.0.iter().zip(b.0).map(|(a, b)| relation.relate(a, b)))?;
337 Ok(GeneratorWitness(types))
341 impl<'tcx> Relate<'tcx> for Ty<'tcx> {
342 fn relate<'a, 'gcx, R>(relation: &mut R,
345 -> RelateResult<'tcx, Ty<'tcx>>
346 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
352 /// The main "type relation" routine. Note that this does not handle
353 /// inference artifacts, so you should filter those out before calling
355 pub fn super_relate_tys<'a, 'gcx, 'tcx, R>(relation: &mut R,
358 -> RelateResult<'tcx, Ty<'tcx>>
359 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
361 let tcx = relation.tcx();
362 debug!("super_relate_tys: a={:?} b={:?}", a, b);
363 match (&a.sty, &b.sty) {
365 (_, &ty::Infer(_)) =>
367 // The caller should handle these cases!
368 bug!("var types encountered in super_relate_tys")
371 (ty::Bound(..), _) | (_, ty::Bound(..)) => {
372 bug!("bound types encountered in super_relate_tys")
375 (&ty::Error, _) | (_, &ty::Error) =>
392 (&ty::Param(ref a_p), &ty::Param(ref b_p))
393 if a_p.idx == b_p.idx =>
398 (ty::Placeholder(p1), ty::Placeholder(p2)) if p1 == p2 => {
402 (&ty::Adt(a_def, a_substs), &ty::Adt(b_def, b_substs))
405 let substs = relation.relate_item_substs(a_def.did, a_substs, b_substs)?;
406 Ok(tcx.mk_adt(a_def, substs))
409 (&ty::Foreign(a_id), &ty::Foreign(b_id))
412 Ok(tcx.mk_foreign(a_id))
415 (&ty::Dynamic(ref a_obj, ref a_region), &ty::Dynamic(ref b_obj, ref b_region)) => {
416 let region_bound = relation.with_cause(Cause::ExistentialRegionBound,
418 relation.relate_with_variance(
423 Ok(tcx.mk_dynamic(relation.relate(a_obj, b_obj)?, region_bound))
426 (&ty::Generator(a_id, a_substs, movability),
427 &ty::Generator(b_id, b_substs, _))
430 // All Generator types with the same id represent
431 // the (anonymous) type of the same generator expression. So
432 // all of their regions should be equated.
433 let substs = relation.relate(&a_substs, &b_substs)?;
434 Ok(tcx.mk_generator(a_id, substs, movability))
437 (&ty::GeneratorWitness(a_types), &ty::GeneratorWitness(b_types)) =>
439 // Wrap our types with a temporary GeneratorWitness struct
440 // inside the binder so we can related them
441 let a_types = a_types.map_bound(GeneratorWitness);
442 let b_types = b_types.map_bound(GeneratorWitness);
443 // Then remove the GeneratorWitness for the result
444 let types = relation.relate(&a_types, &b_types)?.map_bound(|witness| witness.0);
445 Ok(tcx.mk_generator_witness(types))
448 (&ty::Closure(a_id, a_substs),
449 &ty::Closure(b_id, b_substs))
452 // All Closure types with the same id represent
453 // the (anonymous) type of the same closure expression. So
454 // all of their regions should be equated.
455 let substs = relation.relate(&a_substs, &b_substs)?;
456 Ok(tcx.mk_closure(a_id, substs))
459 (&ty::RawPtr(ref a_mt), &ty::RawPtr(ref b_mt)) =>
461 let mt = relation.relate(a_mt, b_mt)?;
465 (&ty::Ref(a_r, a_ty, a_mutbl), &ty::Ref(b_r, b_ty, b_mutbl)) =>
467 let r = relation.relate_with_variance(ty::Contravariant, &a_r, &b_r)?;
468 let a_mt = ty::TypeAndMut { ty: a_ty, mutbl: a_mutbl };
469 let b_mt = ty::TypeAndMut { ty: b_ty, mutbl: b_mutbl };
470 let mt = relation.relate(&a_mt, &b_mt)?;
471 Ok(tcx.mk_ref(r, mt))
474 (&ty::Array(a_t, sz_a), &ty::Array(b_t, sz_b)) =>
476 let t = relation.relate(&a_t, &b_t)?;
477 let to_u64 = |x: ty::Const<'tcx>| -> Result<u64, ErrorReported> {
479 ConstValue::Unevaluated(def_id, substs) => {
480 // FIXME(eddyb) get the right param_env.
481 let param_env = ty::ParamEnv::empty();
482 if let Some(substs) = tcx.lift_to_global(&substs) {
483 let instance = ty::Instance::resolve(
489 if let Some(instance) = instance {
494 if let Some(s) = tcx.const_eval(param_env.and(cid))
496 .map(|c| c.unwrap_usize(tcx)) {
501 tcx.sess.delay_span_bug(tcx.def_span(def_id),
502 "array length could not be evaluated");
505 _ => x.assert_usize(tcx).ok_or_else(|| {
506 tcx.sess.delay_span_bug(DUMMY_SP,
507 "array length could not be evaluated");
512 match (to_u64(*sz_a), to_u64(*sz_b)) {
513 (Ok(sz_a_u64), Ok(sz_b_u64)) => {
514 if sz_a_u64 == sz_b_u64 {
515 Ok(tcx.mk_ty(ty::Array(t, sz_a)))
517 Err(TypeError::FixedArraySize(
518 expected_found(relation, &sz_a_u64, &sz_b_u64)))
521 // We reported an error or will ICE, so we can return Error.
522 (Err(ErrorReported), _) | (_, Err(ErrorReported)) => {
528 (&ty::Slice(a_t), &ty::Slice(b_t)) =>
530 let t = relation.relate(&a_t, &b_t)?;
534 (&ty::Tuple(as_), &ty::Tuple(bs)) =>
536 if as_.len() == bs.len() {
537 Ok(tcx.mk_tup(as_.iter().zip(bs).map(|(a, b)| {
538 relation.relate(&a.expect_ty(), &b.expect_ty())
540 } else if !(as_.is_empty() || bs.is_empty()) {
541 Err(TypeError::TupleSize(
542 expected_found(relation, &as_.len(), &bs.len())))
544 Err(TypeError::Sorts(expected_found(relation, &a, &b)))
548 (&ty::FnDef(a_def_id, a_substs), &ty::FnDef(b_def_id, b_substs))
549 if a_def_id == b_def_id =>
551 let substs = relation.relate_item_substs(a_def_id, a_substs, b_substs)?;
552 Ok(tcx.mk_fn_def(a_def_id, substs))
555 (&ty::FnPtr(a_fty), &ty::FnPtr(b_fty)) =>
557 let fty = relation.relate(&a_fty, &b_fty)?;
558 Ok(tcx.mk_fn_ptr(fty))
561 (ty::UnnormalizedProjection(a_data), ty::UnnormalizedProjection(b_data)) => {
562 let projection_ty = relation.relate(a_data, b_data)?;
563 Ok(tcx.mk_ty(ty::UnnormalizedProjection(projection_ty)))
566 // these two are already handled downstream in case of lazy normalization
567 (ty::Projection(a_data), ty::Projection(b_data)) => {
568 let projection_ty = relation.relate(a_data, b_data)?;
569 Ok(tcx.mk_projection(projection_ty.item_def_id, projection_ty.substs))
572 (&ty::Opaque(a_def_id, a_substs), &ty::Opaque(b_def_id, b_substs))
573 if a_def_id == b_def_id =>
575 let substs = relate_substs(relation, None, a_substs, b_substs)?;
576 Ok(tcx.mk_opaque(a_def_id, substs))
581 Err(TypeError::Sorts(expected_found(relation, &a, &b)))
586 /// The main "const relation" routine. Note that this does not handle
587 /// inference artifacts, so you should filter those out before calling
589 pub fn super_relate_consts<'a, 'gcx, 'tcx, R>(
591 a: &'tcx ty::LazyConst<'tcx>,
592 b: &'tcx ty::LazyConst<'tcx>
593 ) -> RelateResult<'tcx, &'tcx ty::LazyConst<'tcx>>
595 R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
597 let tcx = relation.tcx();
600 (ty::LazyConst::Evaluated(a_eval), ty::LazyConst::Evaluated(b_eval)) => {
601 // Only consts whose types are equal should be compared.
602 assert_eq!(a_eval.ty, b_eval.ty);
604 // Currently, the values that can be unified are those that
605 // implement both `PartialEq` and `Eq`, corresponding to
606 // `structural_match` types.
607 // FIXME(const_generics): check for `structural_match` synthetic attribute.
608 match (a_eval.val, b_eval.val) {
609 (ConstValue::Infer(_), _) | (_, ConstValue::Infer(_)) => {
610 // The caller should handle these cases!
611 bug!("var types encountered in super_relate_consts: {:?} {:?}", a, b)
613 (ConstValue::Param(a_p), ConstValue::Param(b_p)) if a_p.index == b_p.index => {
616 (ConstValue::Scalar(Scalar::Bits { .. }), _) if a == b => {
619 (ConstValue::ByRef(..), _) => {
621 "non-Scalar ConstValue encountered in super_relate_consts {:?} {:?}",
627 Err(TypeError::ConstError(
628 ConstError::Mismatch(expected_found(relation, &a, &b))
633 // FIXME(const_generics): this is probably wrong (regarding TyProjection)
635 ty::LazyConst::Unevaluated(a_def_id, a_substs),
636 ty::LazyConst::Unevaluated(b_def_id, b_substs),
637 ) if a_def_id == b_def_id => {
639 relation.relate_with_variance(ty::Variance::Invariant, a_substs, b_substs)?;
640 Ok(tcx.mk_lazy_const(ty::LazyConst::Unevaluated(*a_def_id, substs)))
643 Err(TypeError::ConstError(
644 ConstError::Mismatch(expected_found(relation, &a, &b))
650 impl<'tcx> Relate<'tcx> for &'tcx ty::List<ty::ExistentialPredicate<'tcx>> {
651 fn relate<'a, 'gcx, R>(relation: &mut R,
654 -> RelateResult<'tcx, Self>
655 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a {
657 if a.len() != b.len() {
658 return Err(TypeError::ExistentialMismatch(expected_found(relation, a, b)));
661 let tcx = relation.tcx();
662 let v = a.iter().zip(b.iter()).map(|(ep_a, ep_b)| {
663 use crate::ty::ExistentialPredicate::*;
664 match (*ep_a, *ep_b) {
665 (Trait(ref a), Trait(ref b)) => Ok(Trait(relation.relate(a, b)?)),
666 (Projection(ref a), Projection(ref b)) => Ok(Projection(relation.relate(a, b)?)),
667 (AutoTrait(ref a), AutoTrait(ref b)) if a == b => Ok(AutoTrait(*a)),
668 _ => Err(TypeError::ExistentialMismatch(expected_found(relation, a, b)))
671 Ok(tcx.mk_existential_predicates(v)?)
675 impl<'tcx> Relate<'tcx> for ty::ClosureSubsts<'tcx> {
676 fn relate<'a, 'gcx, R>(relation: &mut R,
677 a: &ty::ClosureSubsts<'tcx>,
678 b: &ty::ClosureSubsts<'tcx>)
679 -> RelateResult<'tcx, ty::ClosureSubsts<'tcx>>
680 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
682 let substs = relate_substs(relation, None, a.substs, b.substs)?;
683 Ok(ty::ClosureSubsts { substs })
687 impl<'tcx> Relate<'tcx> for ty::GeneratorSubsts<'tcx> {
688 fn relate<'a, 'gcx, R>(relation: &mut R,
689 a: &ty::GeneratorSubsts<'tcx>,
690 b: &ty::GeneratorSubsts<'tcx>)
691 -> RelateResult<'tcx, ty::GeneratorSubsts<'tcx>>
692 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
694 let substs = relate_substs(relation, None, a.substs, b.substs)?;
695 Ok(ty::GeneratorSubsts { substs })
699 impl<'tcx> Relate<'tcx> for SubstsRef<'tcx> {
700 fn relate<'a, 'gcx, R>(relation: &mut R,
703 -> RelateResult<'tcx, SubstsRef<'tcx>>
704 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
706 relate_substs(relation, None, a, b)
710 impl<'tcx> Relate<'tcx> for ty::Region<'tcx> {
711 fn relate<'a, 'gcx, R>(relation: &mut R,
712 a: &ty::Region<'tcx>,
713 b: &ty::Region<'tcx>)
714 -> RelateResult<'tcx, ty::Region<'tcx>>
715 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
717 relation.regions(*a, *b)
721 impl<'tcx, T: Relate<'tcx>> Relate<'tcx> for ty::Binder<T> {
722 fn relate<'a, 'gcx, R>(relation: &mut R,
725 -> RelateResult<'tcx, ty::Binder<T>>
726 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
728 relation.binders(a, b)
732 impl<'tcx, T: Relate<'tcx>> Relate<'tcx> for Rc<T> {
733 fn relate<'a, 'gcx, R>(relation: &mut R,
736 -> RelateResult<'tcx, Rc<T>>
737 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
741 Ok(Rc::new(relation.relate(a, b)?))
745 impl<'tcx, T: Relate<'tcx>> Relate<'tcx> for Box<T> {
746 fn relate<'a, 'gcx, R>(relation: &mut R,
749 -> RelateResult<'tcx, Box<T>>
750 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a
754 Ok(Box::new(relation.relate(a, b)?))
758 impl<'tcx> Relate<'tcx> for Kind<'tcx> {
759 fn relate<'a, 'gcx, R>(
763 ) -> RelateResult<'tcx, Kind<'tcx>>
765 R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'a+'tcx, 'tcx: 'a,
767 match (a.unpack(), b.unpack()) {
768 (UnpackedKind::Lifetime(a_lt), UnpackedKind::Lifetime(b_lt)) => {
769 Ok(relation.relate(&a_lt, &b_lt)?.into())
771 (UnpackedKind::Type(a_ty), UnpackedKind::Type(b_ty)) => {
772 Ok(relation.relate(&a_ty, &b_ty)?.into())
774 (UnpackedKind::Lifetime(unpacked), x) => {
775 bug!("impossible case reached: can't relate: {:?} with {:?}", unpacked, x)
777 (UnpackedKind::Type(unpacked), x) => {
778 bug!("impossible case reached: can't relate: {:?} with {:?}", unpacked, x)
780 (UnpackedKind::Const(_), _) => {
781 unimplemented!() // FIXME(const_generics)
787 impl<'tcx> Relate<'tcx> for ty::TraitPredicate<'tcx> {
788 fn relate<'a, 'gcx, R>(
790 a: &ty::TraitPredicate<'tcx>,
791 b: &ty::TraitPredicate<'tcx>
792 ) -> RelateResult<'tcx, ty::TraitPredicate<'tcx>>
793 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'tcx, 'tcx: 'a
795 Ok(ty::TraitPredicate {
796 trait_ref: relation.relate(&a.trait_ref, &b.trait_ref)?,
801 impl<'tcx> Relate<'tcx> for ty::ProjectionPredicate<'tcx> {
802 fn relate<'a, 'gcx, R>(
804 a: &ty::ProjectionPredicate<'tcx>,
805 b: &ty::ProjectionPredicate<'tcx>,
806 ) -> RelateResult<'tcx, ty::ProjectionPredicate<'tcx>>
807 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'tcx, 'tcx: 'a
809 Ok(ty::ProjectionPredicate {
810 projection_ty: relation.relate(&a.projection_ty, &b.projection_ty)?,
811 ty: relation.relate(&a.ty, &b.ty)?,
816 impl<'tcx> Relate<'tcx> for traits::WhereClause<'tcx> {
817 fn relate<'a, 'gcx, R>(
819 a: &traits::WhereClause<'tcx>,
820 b: &traits::WhereClause<'tcx>
821 ) -> RelateResult<'tcx, traits::WhereClause<'tcx>>
822 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'tcx, 'tcx: 'a
824 use crate::traits::WhereClause::*;
826 (Implemented(a_pred), Implemented(b_pred)) => {
827 Ok(Implemented(relation.relate(a_pred, b_pred)?))
830 (ProjectionEq(a_pred), ProjectionEq(b_pred)) => {
831 Ok(ProjectionEq(relation.relate(a_pred, b_pred)?))
834 (RegionOutlives(a_pred), RegionOutlives(b_pred)) => {
835 Ok(RegionOutlives(ty::OutlivesPredicate(
836 relation.relate(&a_pred.0, &b_pred.0)?,
837 relation.relate(&a_pred.1, &b_pred.1)?,
841 (TypeOutlives(a_pred), TypeOutlives(b_pred)) => {
842 Ok(TypeOutlives(ty::OutlivesPredicate(
843 relation.relate(&a_pred.0, &b_pred.0)?,
844 relation.relate(&a_pred.1, &b_pred.1)?,
848 _ => Err(TypeError::Mismatch),
853 impl<'tcx> Relate<'tcx> for traits::WellFormed<'tcx> {
854 fn relate<'a, 'gcx, R>(
856 a: &traits::WellFormed<'tcx>,
857 b: &traits::WellFormed<'tcx>
858 ) -> RelateResult<'tcx, traits::WellFormed<'tcx>>
859 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'tcx, 'tcx: 'a
861 use crate::traits::WellFormed::*;
863 (Trait(a_pred), Trait(b_pred)) => Ok(Trait(relation.relate(a_pred, b_pred)?)),
864 (Ty(a_ty), Ty(b_ty)) => Ok(Ty(relation.relate(a_ty, b_ty)?)),
865 _ => Err(TypeError::Mismatch),
870 impl<'tcx> Relate<'tcx> for traits::FromEnv<'tcx> {
871 fn relate<'a, 'gcx, R>(
873 a: &traits::FromEnv<'tcx>,
874 b: &traits::FromEnv<'tcx>
875 ) -> RelateResult<'tcx, traits::FromEnv<'tcx>>
876 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'tcx, 'tcx: 'a
878 use crate::traits::FromEnv::*;
880 (Trait(a_pred), Trait(b_pred)) => Ok(Trait(relation.relate(a_pred, b_pred)?)),
881 (Ty(a_ty), Ty(b_ty)) => Ok(Ty(relation.relate(a_ty, b_ty)?)),
882 _ => Err(TypeError::Mismatch),
887 impl<'tcx> Relate<'tcx> for traits::DomainGoal<'tcx> {
888 fn relate<'a, 'gcx, R>(
890 a: &traits::DomainGoal<'tcx>,
891 b: &traits::DomainGoal<'tcx>
892 ) -> RelateResult<'tcx, traits::DomainGoal<'tcx>>
893 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'tcx, 'tcx: 'a
895 use crate::traits::DomainGoal::*;
897 (Holds(a_wc), Holds(b_wc)) => Ok(Holds(relation.relate(a_wc, b_wc)?)),
898 (WellFormed(a_wf), WellFormed(b_wf)) => Ok(WellFormed(relation.relate(a_wf, b_wf)?)),
899 (FromEnv(a_fe), FromEnv(b_fe)) => Ok(FromEnv(relation.relate(a_fe, b_fe)?)),
901 (Normalize(a_pred), Normalize(b_pred)) => {
902 Ok(Normalize(relation.relate(a_pred, b_pred)?))
905 _ => Err(TypeError::Mismatch),
910 impl<'tcx> Relate<'tcx> for traits::Goal<'tcx> {
911 fn relate<'a, 'gcx, R>(
913 a: &traits::Goal<'tcx>,
914 b: &traits::Goal<'tcx>
915 ) -> RelateResult<'tcx, traits::Goal<'tcx>>
916 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'tcx, 'tcx: 'a
918 use crate::traits::GoalKind::*;
920 (Implies(a_clauses, a_goal), Implies(b_clauses, b_goal)) => {
921 let clauses = relation.relate(a_clauses, b_clauses)?;
922 let goal = relation.relate(a_goal, b_goal)?;
923 Ok(relation.tcx().mk_goal(Implies(clauses, goal)))
926 (And(a_left, a_right), And(b_left, b_right)) => {
927 let left = relation.relate(a_left, b_left)?;
928 let right = relation.relate(a_right, b_right)?;
929 Ok(relation.tcx().mk_goal(And(left, right)))
932 (Not(a_goal), Not(b_goal)) => {
933 let goal = relation.relate(a_goal, b_goal)?;
934 Ok(relation.tcx().mk_goal(Not(goal)))
937 (DomainGoal(a_goal), DomainGoal(b_goal)) => {
938 let goal = relation.relate(a_goal, b_goal)?;
939 Ok(relation.tcx().mk_goal(DomainGoal(goal)))
942 (Quantified(a_qkind, a_goal), Quantified(b_qkind, b_goal))
943 if a_qkind == b_qkind =>
945 let goal = relation.relate(a_goal, b_goal)?;
946 Ok(relation.tcx().mk_goal(Quantified(*a_qkind, goal)))
949 (CannotProve, CannotProve) => Ok(*a),
951 _ => Err(TypeError::Mismatch),
956 impl<'tcx> Relate<'tcx> for traits::Goals<'tcx> {
957 fn relate<'a, 'gcx, R>(
959 a: &traits::Goals<'tcx>,
960 b: &traits::Goals<'tcx>
961 ) -> RelateResult<'tcx, traits::Goals<'tcx>>
962 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'tcx, 'tcx: 'a
964 if a.len() != b.len() {
965 return Err(TypeError::Mismatch);
968 let tcx = relation.tcx();
969 let goals = a.iter().zip(b.iter()).map(|(a, b)| relation.relate(a, b));
970 Ok(tcx.mk_goals(goals)?)
974 impl<'tcx> Relate<'tcx> for traits::Clause<'tcx> {
975 fn relate<'a, 'gcx, R>(
977 a: &traits::Clause<'tcx>,
978 b: &traits::Clause<'tcx>
979 ) -> RelateResult<'tcx, traits::Clause<'tcx>>
980 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'tcx, 'tcx: 'a
982 use crate::traits::Clause::*;
984 (Implies(a_clause), Implies(b_clause)) => {
985 let clause = relation.relate(a_clause, b_clause)?;
989 (ForAll(a_clause), ForAll(b_clause)) => {
990 let clause = relation.relate(a_clause, b_clause)?;
994 _ => Err(TypeError::Mismatch),
999 impl<'tcx> Relate<'tcx> for traits::Clauses<'tcx> {
1000 fn relate<'a, 'gcx, R>(
1002 a: &traits::Clauses<'tcx>,
1003 b: &traits::Clauses<'tcx>
1004 ) -> RelateResult<'tcx, traits::Clauses<'tcx>>
1005 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'tcx, 'tcx: 'a
1007 if a.len() != b.len() {
1008 return Err(TypeError::Mismatch);
1011 let tcx = relation.tcx();
1012 let clauses = a.iter().zip(b.iter()).map(|(a, b)| relation.relate(a, b));
1013 Ok(tcx.mk_clauses(clauses)?)
1017 impl<'tcx> Relate<'tcx> for traits::ProgramClause<'tcx> {
1018 fn relate<'a, 'gcx, R>(
1020 a: &traits::ProgramClause<'tcx>,
1021 b: &traits::ProgramClause<'tcx>
1022 ) -> RelateResult<'tcx, traits::ProgramClause<'tcx>>
1023 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'tcx, 'tcx: 'a
1025 Ok(traits::ProgramClause {
1026 goal: relation.relate(&a.goal, &b.goal)?,
1027 hypotheses: relation.relate(&a.hypotheses, &b.hypotheses)?,
1028 category: traits::ProgramClauseCategory::Other,
1033 impl<'tcx> Relate<'tcx> for traits::Environment<'tcx> {
1034 fn relate<'a, 'gcx, R>(
1036 a: &traits::Environment<'tcx>,
1037 b: &traits::Environment<'tcx>
1038 ) -> RelateResult<'tcx, traits::Environment<'tcx>>
1039 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'tcx, 'tcx: 'a
1041 Ok(traits::Environment {
1042 clauses: relation.relate(&a.clauses, &b.clauses)?,
1047 impl<'tcx, G> Relate<'tcx> for traits::InEnvironment<'tcx, G>
1048 where G: Relate<'tcx>
1050 fn relate<'a, 'gcx, R>(
1052 a: &traits::InEnvironment<'tcx, G>,
1053 b: &traits::InEnvironment<'tcx, G>
1054 ) -> RelateResult<'tcx, traits::InEnvironment<'tcx, G>>
1055 where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'tcx, 'tcx: 'a
1057 Ok(traits::InEnvironment {
1058 environment: relation.relate(&a.environment, &b.environment)?,
1059 goal: relation.relate(&a.goal, &b.goal)?,
1064 ///////////////////////////////////////////////////////////////////////////
1067 pub fn expected_found<'a, 'gcx, 'tcx, R, T>(relation: &mut R,
1071 where R: TypeRelation<'a, 'gcx, 'tcx>, T: Clone, 'gcx: 'a+'tcx, 'tcx: 'a
1073 expected_found_bool(relation.a_is_expected(), a, b)
1076 pub fn expected_found_bool<T>(a_is_expected: bool,
1085 ExpectedFound {expected: a, found: b}
1087 ExpectedFound {expected: b, found: a}