hir_ty/next_solver/
predicate.rs

1//! Things related to predicates.
2
3use std::cmp::Ordering;
4
5use intern::{
6    Interned, InternedRef, InternedSlice, InternedSliceRef, impl_internable, impl_slice_internable,
7};
8use macros::{GenericTypeVisitable, TypeFoldable, TypeVisitable};
9use rustc_type_ir::{
10    self as ty, CollectAndApply, EarlyBinder, FlagComputation, Flags, GenericTypeVisitable,
11    PredicatePolarity, TypeFoldable, TypeSuperFoldable, TypeSuperVisitable, TypeVisitable, Upcast,
12    UpcastFrom, WithCachedTypeInfo,
13    elaborate::Elaboratable,
14    error::{ExpectedFound, TypeError},
15    inherent::{IntoKind, SliceLike},
16};
17
18use crate::next_solver::{
19    GenericArg, TraitIdWrapper, impl_foldable_for_interned_slice, impl_stored_interned_slice,
20    interned_slice,
21};
22
23use super::{Binder, BoundVarKinds, DbInterner, Region, Ty};
24
25pub type BoundExistentialPredicate<'db> = Binder<'db, ExistentialPredicate<'db>>;
26
27pub type TraitRef<'db> = ty::TraitRef<DbInterner<'db>>;
28pub type AliasTerm<'db> = ty::AliasTerm<DbInterner<'db>>;
29pub type ProjectionPredicate<'db> = ty::ProjectionPredicate<DbInterner<'db>>;
30pub type ExistentialPredicate<'db> = ty::ExistentialPredicate<DbInterner<'db>>;
31pub type ExistentialTraitRef<'db> = ty::ExistentialTraitRef<DbInterner<'db>>;
32pub type ExistentialProjection<'db> = ty::ExistentialProjection<DbInterner<'db>>;
33pub type TraitPredicate<'db> = ty::TraitPredicate<DbInterner<'db>>;
34pub type HostEffectPredicate<'db> = ty::HostEffectPredicate<DbInterner<'db>>;
35pub type ClauseKind<'db> = ty::ClauseKind<DbInterner<'db>>;
36pub type PredicateKind<'db> = ty::PredicateKind<DbInterner<'db>>;
37pub type NormalizesTo<'db> = ty::NormalizesTo<DbInterner<'db>>;
38pub type CoercePredicate<'db> = ty::CoercePredicate<DbInterner<'db>>;
39pub type SubtypePredicate<'db> = ty::SubtypePredicate<DbInterner<'db>>;
40pub type OutlivesPredicate<'db, T> = ty::OutlivesPredicate<DbInterner<'db>, T>;
41pub type RegionOutlivesPredicate<'db> = OutlivesPredicate<'db, Region<'db>>;
42pub type TypeOutlivesPredicate<'db> = OutlivesPredicate<'db, Ty<'db>>;
43pub type PolyTraitPredicate<'db> = Binder<'db, TraitPredicate<'db>>;
44pub type PolyRegionOutlivesPredicate<'db> = Binder<'db, RegionOutlivesPredicate<'db>>;
45pub type PolyTypeOutlivesPredicate<'db> = Binder<'db, TypeOutlivesPredicate<'db>>;
46pub type PolySubtypePredicate<'db> = Binder<'db, SubtypePredicate<'db>>;
47pub type PolyCoercePredicate<'db> = Binder<'db, CoercePredicate<'db>>;
48pub type PolyProjectionPredicate<'db> = Binder<'db, ProjectionPredicate<'db>>;
49pub type PolyTraitRef<'db> = Binder<'db, TraitRef<'db>>;
50pub type PolyExistentialTraitRef<'db> = Binder<'db, ExistentialTraitRef<'db>>;
51pub type PolyExistentialProjection<'db> = Binder<'db, ExistentialProjection<'db>>;
52pub type ArgOutlivesPredicate<'db> = OutlivesPredicate<'db, GenericArg<'db>>;
53
54/// Compares via an ordering that will not change if modules are reordered or other changes are
55/// made to the tree. In particular, this ordering is preserved across incremental compilations.
56fn stable_cmp_existential_predicate<'db>(
57    a: &ExistentialPredicate<'db>,
58    b: &ExistentialPredicate<'db>,
59) -> Ordering {
60    // FIXME: this is actual unstable - see impl in predicate.rs in `rustc_middle`
61    match (a, b) {
62        (ExistentialPredicate::Trait(_), ExistentialPredicate::Trait(_)) => Ordering::Equal,
63        (ExistentialPredicate::Projection(_a), ExistentialPredicate::Projection(_b)) => {
64            // Should sort by def path hash
65            Ordering::Equal
66        }
67        (ExistentialPredicate::AutoTrait(_a), ExistentialPredicate::AutoTrait(_b)) => {
68            // Should sort by def path hash
69            Ordering::Equal
70        }
71        (ExistentialPredicate::Trait(_), _) => Ordering::Less,
72        (ExistentialPredicate::Projection(_), ExistentialPredicate::Trait(_)) => Ordering::Greater,
73        (ExistentialPredicate::Projection(_), _) => Ordering::Less,
74        (ExistentialPredicate::AutoTrait(_), _) => Ordering::Greater,
75    }
76}
77interned_slice!(
78    BoundExistentialPredicatesStorage,
79    BoundExistentialPredicates,
80    StoredBoundExistentialPredicates,
81    bound_existential_predicates,
82    BoundExistentialPredicate<'db>,
83    BoundExistentialPredicate<'static>,
84);
85impl_foldable_for_interned_slice!(BoundExistentialPredicates);
86
87impl<'db> rustc_type_ir::inherent::BoundExistentialPredicates<DbInterner<'db>>
88    for BoundExistentialPredicates<'db>
89{
90    fn principal_def_id(self) -> Option<TraitIdWrapper> {
91        self.principal().map(|trait_ref| trait_ref.skip_binder().def_id)
92    }
93
94    fn principal(
95        self,
96    ) -> Option<
97        rustc_type_ir::Binder<DbInterner<'db>, rustc_type_ir::ExistentialTraitRef<DbInterner<'db>>>,
98    > {
99        self[0]
100            .map_bound(|this| match this {
101                ExistentialPredicate::Trait(tr) => Some(tr),
102                _ => None,
103            })
104            .transpose()
105    }
106
107    fn auto_traits(self) -> impl IntoIterator<Item = TraitIdWrapper> {
108        self.iter().filter_map(|predicate| match predicate.skip_binder() {
109            ExistentialPredicate::AutoTrait(did) => Some(did),
110            _ => None,
111        })
112    }
113
114    fn projection_bounds(
115        self,
116    ) -> impl IntoIterator<
117        Item = rustc_type_ir::Binder<
118            DbInterner<'db>,
119            rustc_type_ir::ExistentialProjection<DbInterner<'db>>,
120        >,
121    > {
122        self.iter().filter_map(|predicate| {
123            predicate
124                .map_bound(|pred| match pred {
125                    ExistentialPredicate::Projection(projection) => Some(projection),
126                    _ => None,
127                })
128                .transpose()
129        })
130    }
131}
132
133impl<'db> rustc_type_ir::relate::Relate<DbInterner<'db>> for BoundExistentialPredicates<'db> {
134    fn relate<R: rustc_type_ir::relate::TypeRelation<DbInterner<'db>>>(
135        relation: &mut R,
136        a: Self,
137        b: Self,
138    ) -> rustc_type_ir::relate::RelateResult<DbInterner<'db>, Self> {
139        let interner = relation.cx();
140
141        // We need to perform this deduplication as we sometimes generate duplicate projections in `a`.
142        let mut a_v: Vec<_> = a.into_iter().collect();
143        let mut b_v: Vec<_> = b.into_iter().collect();
144        // `skip_binder` here is okay because `stable_cmp` doesn't look at binders
145        a_v.sort_by(|a, b| {
146            stable_cmp_existential_predicate(a.as_ref().skip_binder(), b.as_ref().skip_binder())
147        });
148        a_v.dedup();
149        b_v.sort_by(|a, b| {
150            stable_cmp_existential_predicate(a.as_ref().skip_binder(), b.as_ref().skip_binder())
151        });
152        b_v.dedup();
153        if a_v.len() != b_v.len() {
154            return Err(TypeError::ExistentialMismatch(ExpectedFound::new(a, b)));
155        }
156
157        let v = std::iter::zip(a_v, b_v).map(
158            |(ep_a, ep_b): (
159                Binder<'_, ty::ExistentialPredicate<_>>,
160                Binder<'_, ty::ExistentialPredicate<_>>,
161            )| {
162                match (ep_a.skip_binder(), ep_b.skip_binder()) {
163                    (ty::ExistentialPredicate::Trait(a), ty::ExistentialPredicate::Trait(b)) => {
164                        Ok(ep_a.rebind(ty::ExistentialPredicate::Trait(
165                            relation.relate(ep_a.rebind(a), ep_b.rebind(b))?.skip_binder(),
166                        )))
167                    }
168                    (
169                        ty::ExistentialPredicate::Projection(a),
170                        ty::ExistentialPredicate::Projection(b),
171                    ) => Ok(ep_a.rebind(ty::ExistentialPredicate::Projection(
172                        relation.relate(ep_a.rebind(a), ep_b.rebind(b))?.skip_binder(),
173                    ))),
174                    (
175                        ty::ExistentialPredicate::AutoTrait(a),
176                        ty::ExistentialPredicate::AutoTrait(b),
177                    ) if a == b => Ok(ep_a.rebind(ty::ExistentialPredicate::AutoTrait(a))),
178                    _ => Err(TypeError::ExistentialMismatch(ExpectedFound::new(a, b))),
179                }
180            },
181        );
182
183        BoundExistentialPredicates::new_from_iter(interner, v)
184    }
185}
186
187#[derive(Clone, Copy, PartialEq, Eq, Hash)]
188pub struct Predicate<'db> {
189    interned: InternedRef<'db, PredicateInterned>,
190}
191
192#[derive(PartialEq, Eq, Hash, GenericTypeVisitable)]
193pub(super) struct PredicateInterned(WithCachedTypeInfo<Binder<'static, PredicateKind<'static>>>);
194
195impl_internable!(gc; PredicateInterned);
196
197const _: () = {
198    const fn is_copy<T: Copy>() {}
199    is_copy::<Predicate<'static>>();
200};
201
202impl<'db> Predicate<'db> {
203    pub fn new(_interner: DbInterner<'db>, kind: Binder<'db, PredicateKind<'db>>) -> Self {
204        let kind = unsafe {
205            std::mem::transmute::<
206                Binder<'db, PredicateKind<'db>>,
207                Binder<'static, PredicateKind<'static>>,
208            >(kind)
209        };
210        let flags = FlagComputation::for_predicate(kind);
211        let cached = WithCachedTypeInfo {
212            internee: kind,
213            flags: flags.flags,
214            outer_exclusive_binder: flags.outer_exclusive_binder,
215        };
216        Self { interned: Interned::new_gc(PredicateInterned(cached)) }
217    }
218
219    pub fn inner(&self) -> &WithCachedTypeInfo<Binder<'db, PredicateKind<'db>>> {
220        let inner = &self.interned.0;
221        unsafe {
222            std::mem::transmute::<
223                &WithCachedTypeInfo<Binder<'static, PredicateKind<'static>>>,
224                &WithCachedTypeInfo<Binder<'db, PredicateKind<'db>>>,
225            >(inner)
226        }
227    }
228
229    /// Flips the polarity of a Predicate.
230    ///
231    /// Given `T: Trait` predicate it returns `T: !Trait` and given `T: !Trait` returns `T: Trait`.
232    pub fn flip_polarity(self, interner: DbInterner<'db>) -> Option<Predicate<'db>> {
233        let kind = self
234            .kind()
235            .map_bound(|kind| match kind {
236                PredicateKind::Clause(ClauseKind::Trait(TraitPredicate {
237                    trait_ref,
238                    polarity,
239                })) => Some(PredicateKind::Clause(ClauseKind::Trait(TraitPredicate {
240                    trait_ref,
241                    polarity: polarity.flip(),
242                }))),
243
244                _ => None,
245            })
246            .transpose()?;
247
248        Some(Predicate::new(interner, kind))
249    }
250}
251
252impl<'db> std::fmt::Debug for Predicate<'db> {
253    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
254        self.kind().fmt(f)
255    }
256}
257
258#[derive(Clone, Copy, PartialEq, Eq, Hash, GenericTypeVisitable)]
259pub struct ClausesCachedTypeInfo(WithCachedTypeInfo<()>);
260
261impl_slice_internable!(gc; ClausesStorage, ClausesCachedTypeInfo, Clause<'static>);
262impl_stored_interned_slice!(ClausesStorage, Clauses, StoredClauses);
263
264#[derive(Clone, Copy, PartialEq, Eq, Hash)]
265pub struct Clauses<'db> {
266    interned: InternedSliceRef<'db, ClausesStorage>,
267}
268
269impl<'db> std::fmt::Debug for Clauses<'db> {
270    fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
271        self.as_slice().fmt(fmt)
272    }
273}
274
275impl<'db> Clauses<'db> {
276    #[inline]
277    pub fn empty(interner: DbInterner<'db>) -> Self {
278        interner.default_types().empty.clauses
279    }
280
281    #[inline]
282    pub fn new_from_slice(slice: &[Clause<'db>]) -> Self {
283        let slice = unsafe { ::std::mem::transmute::<&[Clause<'db>], &[Clause<'static>]>(slice) };
284        let flags = FlagComputation::<DbInterner<'db>>::for_clauses(slice);
285        let flags = ClausesCachedTypeInfo(WithCachedTypeInfo {
286            internee: (),
287            flags: flags.flags,
288            outer_exclusive_binder: flags.outer_exclusive_binder,
289        });
290        Self { interned: InternedSlice::from_header_and_slice(flags, slice) }
291    }
292
293    #[inline]
294    pub fn new_from_iter<I, T>(_interner: DbInterner<'db>, args: I) -> T::Output
295    where
296        I: IntoIterator<Item = T>,
297        T: CollectAndApply<Clause<'db>, Self>,
298    {
299        CollectAndApply::collect_and_apply(args.into_iter(), Self::new_from_slice)
300    }
301
302    #[inline]
303    pub fn as_slice(self) -> &'db [Clause<'db>] {
304        let slice = &self.interned.get().slice;
305        unsafe { ::std::mem::transmute::<&[Clause<'static>], &[Clause<'db>]>(slice) }
306    }
307
308    #[inline]
309    pub fn iter(self) -> ::std::iter::Copied<::std::slice::Iter<'db, Clause<'db>>> {
310        self.as_slice().iter().copied()
311    }
312
313    #[inline]
314    pub fn len(self) -> usize {
315        self.as_slice().len()
316    }
317
318    #[inline]
319    pub fn is_empty(self) -> bool {
320        self.as_slice().is_empty()
321    }
322}
323
324impl<'db> IntoIterator for Clauses<'db> {
325    type IntoIter = ::std::iter::Copied<::std::slice::Iter<'db, Clause<'db>>>;
326    type Item = Clause<'db>;
327    #[inline]
328    fn into_iter(self) -> Self::IntoIter {
329        self.iter()
330    }
331}
332
333impl<'db> std::ops::Deref for Clauses<'db> {
334    type Target = [Clause<'db>];
335
336    #[inline]
337    fn deref(&self) -> &Self::Target {
338        (*self).as_slice()
339    }
340}
341
342impl<'db> rustc_type_ir::inherent::SliceLike for Clauses<'db> {
343    type Item = Clause<'db>;
344
345    type IntoIter = ::std::iter::Copied<::std::slice::Iter<'db, Clause<'db>>>;
346
347    #[inline]
348    fn iter(self) -> Self::IntoIter {
349        self.iter()
350    }
351
352    #[inline]
353    fn as_slice(&self) -> &[Self::Item] {
354        (*self).as_slice()
355    }
356}
357
358impl<'db> rustc_type_ir::inherent::Clauses<DbInterner<'db>> for Clauses<'db> {}
359
360impl<'db> rustc_type_ir::TypeSuperFoldable<DbInterner<'db>> for Clauses<'db> {
361    fn try_super_fold_with<F: rustc_type_ir::FallibleTypeFolder<DbInterner<'db>>>(
362        self,
363        folder: &mut F,
364    ) -> Result<Self, F::Error> {
365        Clauses::new_from_iter(folder.cx(), self.iter().map(|clause| clause.try_fold_with(folder)))
366    }
367
368    fn super_fold_with<F: rustc_type_ir::TypeFolder<DbInterner<'db>>>(
369        self,
370        folder: &mut F,
371    ) -> Self {
372        Clauses::new_from_iter(folder.cx(), self.iter().map(|clause| clause.fold_with(folder)))
373    }
374}
375
376impl<'db> rustc_type_ir::TypeFoldable<DbInterner<'db>> for Clauses<'db> {
377    fn try_fold_with<F: rustc_type_ir::FallibleTypeFolder<DbInterner<'db>>>(
378        self,
379        folder: &mut F,
380    ) -> Result<Self, F::Error> {
381        self.try_super_fold_with(folder)
382    }
383    fn fold_with<F: rustc_type_ir::TypeFolder<DbInterner<'db>>>(self, folder: &mut F) -> Self {
384        self.super_fold_with(folder)
385    }
386}
387
388impl<'db> rustc_type_ir::TypeVisitable<DbInterner<'db>> for Clauses<'db> {
389    fn visit_with<V: rustc_type_ir::TypeVisitor<DbInterner<'db>>>(
390        &self,
391        visitor: &mut V,
392    ) -> V::Result {
393        use rustc_ast_ir::visit::VisitorResult;
394        rustc_ast_ir::walk_visitable_list!(visitor, self.iter());
395        V::Result::output()
396    }
397}
398
399impl<'db, V: super::WorldExposer> rustc_type_ir::GenericTypeVisitable<V> for Clauses<'db> {
400    fn generic_visit_with(&self, visitor: &mut V) {
401        if visitor.on_interned_slice(self.interned).is_continue() {
402            self.as_slice().iter().for_each(|it| it.generic_visit_with(visitor));
403        }
404    }
405}
406
407impl<'db> rustc_type_ir::Flags for Clauses<'db> {
408    #[inline]
409    fn flags(&self) -> rustc_type_ir::TypeFlags {
410        self.interned.header.header.0.flags
411    }
412
413    #[inline]
414    fn outer_exclusive_binder(&self) -> rustc_type_ir::DebruijnIndex {
415        self.interned.header.header.0.outer_exclusive_binder
416    }
417}
418
419impl<'db> rustc_type_ir::TypeSuperVisitable<DbInterner<'db>> for Clauses<'db> {
420    fn super_visit_with<V: rustc_type_ir::TypeVisitor<DbInterner<'db>>>(
421        &self,
422        visitor: &mut V,
423    ) -> V::Result {
424        self.as_slice().visit_with(visitor)
425    }
426}
427
428#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, GenericTypeVisitable)] // TODO implement Debug by hand
429pub struct Clause<'db>(pub(crate) Predicate<'db>);
430
431// We could cram the reveal into the clauses like rustc does, probably
432#[derive(
433    Copy, Clone, Debug, Hash, PartialEq, Eq, TypeVisitable, TypeFoldable, GenericTypeVisitable,
434)]
435pub struct ParamEnv<'db> {
436    pub(crate) clauses: Clauses<'db>,
437}
438
439impl<'db> ParamEnv<'db> {
440    pub fn empty(interner: DbInterner<'db>) -> Self {
441        ParamEnv { clauses: Clauses::empty(interner) }
442    }
443
444    pub fn clauses(self) -> Clauses<'db> {
445        self.clauses
446    }
447}
448
449impl<'db> rustc_type_ir::inherent::ParamEnv<DbInterner<'db>> for ParamEnv<'db> {
450    fn caller_bounds(self) -> impl rustc_type_ir::inherent::SliceLike<Item = Clause<'db>> {
451        self.clauses
452    }
453}
454
455#[derive(Clone, Debug, PartialEq, Eq, Hash)]
456pub struct ParamEnvAnd<'db, T> {
457    pub param_env: ParamEnv<'db>,
458    pub value: T,
459}
460
461impl<'db, T> ParamEnvAnd<'db, T> {
462    pub fn into_parts(self) -> (ParamEnv<'db>, T) {
463        (self.param_env, self.value)
464    }
465}
466
467impl<'db> TypeVisitable<DbInterner<'db>> for Predicate<'db> {
468    fn visit_with<V: rustc_type_ir::TypeVisitor<DbInterner<'db>>>(
469        &self,
470        visitor: &mut V,
471    ) -> V::Result {
472        visitor.visit_predicate(*self)
473    }
474}
475
476impl<'db, V: super::WorldExposer> GenericTypeVisitable<V> for Predicate<'db> {
477    fn generic_visit_with(&self, visitor: &mut V) {
478        if visitor.on_interned(self.interned).is_continue() {
479            self.kind().generic_visit_with(visitor);
480        }
481    }
482}
483
484impl<'db> TypeSuperVisitable<DbInterner<'db>> for Predicate<'db> {
485    fn super_visit_with<V: rustc_type_ir::TypeVisitor<DbInterner<'db>>>(
486        &self,
487        visitor: &mut V,
488    ) -> V::Result {
489        (*self).kind().visit_with(visitor)
490    }
491}
492
493impl<'db> TypeFoldable<DbInterner<'db>> for Predicate<'db> {
494    fn try_fold_with<F: rustc_type_ir::FallibleTypeFolder<DbInterner<'db>>>(
495        self,
496        folder: &mut F,
497    ) -> Result<Self, F::Error> {
498        folder.try_fold_predicate(self)
499    }
500    fn fold_with<F: rustc_type_ir::TypeFolder<DbInterner<'db>>>(self, folder: &mut F) -> Self {
501        folder.fold_predicate(self)
502    }
503}
504
505impl<'db> TypeSuperFoldable<DbInterner<'db>> for Predicate<'db> {
506    fn try_super_fold_with<F: rustc_type_ir::FallibleTypeFolder<DbInterner<'db>>>(
507        self,
508        folder: &mut F,
509    ) -> Result<Self, F::Error> {
510        let new = self.kind().try_fold_with(folder)?;
511        Ok(Predicate::new(folder.cx(), new))
512    }
513    fn super_fold_with<F: rustc_type_ir::TypeFolder<DbInterner<'db>>>(
514        self,
515        folder: &mut F,
516    ) -> Self {
517        let new = self.kind().fold_with(folder);
518        Predicate::new(folder.cx(), new)
519    }
520}
521
522impl<'db> Elaboratable<DbInterner<'db>> for Predicate<'db> {
523    fn predicate(&self) -> <DbInterner<'db> as rustc_type_ir::Interner>::Predicate {
524        *self
525    }
526
527    fn child(&self, clause: <DbInterner<'db> as rustc_type_ir::Interner>::Clause) -> Self {
528        clause.as_predicate()
529    }
530
531    fn child_with_derived_cause(
532        &self,
533        clause: <DbInterner<'db> as rustc_type_ir::Interner>::Clause,
534        _span: <DbInterner<'db> as rustc_type_ir::Interner>::Span,
535        _parent_trait_pred: rustc_type_ir::Binder<
536            DbInterner<'db>,
537            rustc_type_ir::TraitPredicate<DbInterner<'db>>,
538        >,
539        _index: usize,
540    ) -> Self {
541        clause.as_predicate()
542    }
543}
544
545impl<'db> Flags for Predicate<'db> {
546    fn flags(&self) -> rustc_type_ir::TypeFlags {
547        self.inner().flags
548    }
549
550    fn outer_exclusive_binder(&self) -> rustc_type_ir::DebruijnIndex {
551        self.inner().outer_exclusive_binder
552    }
553}
554
555impl<'db> IntoKind for Predicate<'db> {
556    type Kind = Binder<'db, PredicateKind<'db>>;
557
558    fn kind(self) -> Self::Kind {
559        self.inner().internee
560    }
561}
562
563impl<'db> UpcastFrom<DbInterner<'db>, ty::PredicateKind<DbInterner<'db>>> for Predicate<'db> {
564    fn upcast_from(from: ty::PredicateKind<DbInterner<'db>>, interner: DbInterner<'db>) -> Self {
565        Binder::dummy(from).upcast(interner)
566    }
567}
568impl<'db>
569    UpcastFrom<DbInterner<'db>, ty::Binder<DbInterner<'db>, ty::PredicateKind<DbInterner<'db>>>>
570    for Predicate<'db>
571{
572    fn upcast_from(
573        from: ty::Binder<DbInterner<'db>, ty::PredicateKind<DbInterner<'db>>>,
574        interner: DbInterner<'db>,
575    ) -> Self {
576        Predicate::new(interner, from)
577    }
578}
579impl<'db> UpcastFrom<DbInterner<'db>, ty::ClauseKind<DbInterner<'db>>> for Predicate<'db> {
580    fn upcast_from(from: ty::ClauseKind<DbInterner<'db>>, interner: DbInterner<'db>) -> Self {
581        Binder::dummy(PredicateKind::Clause(from)).upcast(interner)
582    }
583}
584impl<'db> UpcastFrom<DbInterner<'db>, ty::Binder<DbInterner<'db>, ty::ClauseKind<DbInterner<'db>>>>
585    for Predicate<'db>
586{
587    fn upcast_from(
588        from: ty::Binder<DbInterner<'db>, ty::ClauseKind<DbInterner<'db>>>,
589        interner: DbInterner<'db>,
590    ) -> Self {
591        from.map_bound(PredicateKind::Clause).upcast(interner)
592    }
593}
594impl<'db> UpcastFrom<DbInterner<'db>, Clause<'db>> for Predicate<'db> {
595    fn upcast_from(from: Clause<'db>, _interner: DbInterner<'db>) -> Self {
596        from.0
597    }
598}
599impl<'db> UpcastFrom<DbInterner<'db>, ty::NormalizesTo<DbInterner<'db>>> for Predicate<'db> {
600    fn upcast_from(from: ty::NormalizesTo<DbInterner<'db>>, interner: DbInterner<'db>) -> Self {
601        PredicateKind::NormalizesTo(from).upcast(interner)
602    }
603}
604impl<'db> UpcastFrom<DbInterner<'db>, ty::TraitRef<DbInterner<'db>>> for Predicate<'db> {
605    fn upcast_from(from: ty::TraitRef<DbInterner<'db>>, interner: DbInterner<'db>) -> Self {
606        Binder::dummy(from).upcast(interner)
607    }
608}
609impl<'db> UpcastFrom<DbInterner<'db>, ty::Binder<DbInterner<'db>, ty::TraitRef<DbInterner<'db>>>>
610    for Predicate<'db>
611{
612    fn upcast_from(
613        from: ty::Binder<DbInterner<'db>, ty::TraitRef<DbInterner<'db>>>,
614        interner: DbInterner<'db>,
615    ) -> Self {
616        from.map_bound(|trait_ref| TraitPredicate {
617            trait_ref,
618            polarity: PredicatePolarity::Positive,
619        })
620        .upcast(interner)
621    }
622}
623impl<'db> UpcastFrom<DbInterner<'db>, Binder<'db, ty::TraitPredicate<DbInterner<'db>>>>
624    for Predicate<'db>
625{
626    fn upcast_from(
627        from: Binder<'db, ty::TraitPredicate<DbInterner<'db>>>,
628        interner: DbInterner<'db>,
629    ) -> Self {
630        from.map_bound(|it| PredicateKind::Clause(ClauseKind::Trait(it))).upcast(interner)
631    }
632}
633impl<'db> UpcastFrom<DbInterner<'db>, Binder<'db, ProjectionPredicate<'db>>> for Predicate<'db> {
634    fn upcast_from(from: Binder<'db, ProjectionPredicate<'db>>, interner: DbInterner<'db>) -> Self {
635        from.map_bound(|it| PredicateKind::Clause(ClauseKind::Projection(it))).upcast(interner)
636    }
637}
638impl<'db> UpcastFrom<DbInterner<'db>, ProjectionPredicate<'db>> for Predicate<'db> {
639    fn upcast_from(from: ProjectionPredicate<'db>, interner: DbInterner<'db>) -> Self {
640        PredicateKind::Clause(ClauseKind::Projection(from)).upcast(interner)
641    }
642}
643impl<'db> UpcastFrom<DbInterner<'db>, ty::TraitPredicate<DbInterner<'db>>> for Predicate<'db> {
644    fn upcast_from(from: ty::TraitPredicate<DbInterner<'db>>, interner: DbInterner<'db>) -> Self {
645        PredicateKind::Clause(ClauseKind::Trait(from)).upcast(interner)
646    }
647}
648impl<'db> UpcastFrom<DbInterner<'db>, ty::OutlivesPredicate<DbInterner<'db>, Ty<'db>>>
649    for Predicate<'db>
650{
651    fn upcast_from(
652        from: ty::OutlivesPredicate<DbInterner<'db>, Ty<'db>>,
653        interner: DbInterner<'db>,
654    ) -> Self {
655        PredicateKind::Clause(ClauseKind::TypeOutlives(from)).upcast(interner)
656    }
657}
658impl<'db> UpcastFrom<DbInterner<'db>, ty::OutlivesPredicate<DbInterner<'db>, Region<'db>>>
659    for Predicate<'db>
660{
661    fn upcast_from(
662        from: ty::OutlivesPredicate<DbInterner<'db>, Region<'db>>,
663        interner: DbInterner<'db>,
664    ) -> Self {
665        PredicateKind::Clause(ClauseKind::RegionOutlives(from)).upcast(interner)
666    }
667}
668impl<'db> UpcastFrom<DbInterner<'db>, ty::OutlivesPredicate<DbInterner<'db>, Ty<'db>>>
669    for Clause<'db>
670{
671    fn upcast_from(
672        from: ty::OutlivesPredicate<DbInterner<'db>, Ty<'db>>,
673        interner: DbInterner<'db>,
674    ) -> Self {
675        Clause(from.upcast(interner))
676    }
677}
678impl<'db> UpcastFrom<DbInterner<'db>, ty::OutlivesPredicate<DbInterner<'db>, Region<'db>>>
679    for Clause<'db>
680{
681    fn upcast_from(
682        from: ty::OutlivesPredicate<DbInterner<'db>, Region<'db>>,
683        interner: DbInterner<'db>,
684    ) -> Self {
685        Clause(from.upcast(interner))
686    }
687}
688
689impl<'db> UpcastFrom<DbInterner<'db>, PolyRegionOutlivesPredicate<'db>> for Predicate<'db> {
690    fn upcast_from(from: PolyRegionOutlivesPredicate<'db>, tcx: DbInterner<'db>) -> Self {
691        from.map_bound(|p| PredicateKind::Clause(ClauseKind::RegionOutlives(p))).upcast(tcx)
692    }
693}
694
695impl<'db> rustc_type_ir::inherent::Predicate<DbInterner<'db>> for Predicate<'db> {
696    fn as_clause(self) -> Option<<DbInterner<'db> as rustc_type_ir::Interner>::Clause> {
697        match self.kind().skip_binder() {
698            PredicateKind::Clause(..) => Some(self.expect_clause()),
699            _ => None,
700        }
701    }
702}
703
704impl<'db> Predicate<'db> {
705    pub fn as_trait_clause(self) -> Option<PolyTraitPredicate<'db>> {
706        let predicate = self.kind();
707        match predicate.skip_binder() {
708            PredicateKind::Clause(ClauseKind::Trait(t)) => Some(predicate.rebind(t)),
709            _ => None,
710        }
711    }
712
713    pub fn as_projection_clause(self) -> Option<PolyProjectionPredicate<'db>> {
714        let predicate = self.kind();
715        match predicate.skip_binder() {
716            PredicateKind::Clause(ClauseKind::Projection(t)) => Some(predicate.rebind(t)),
717            _ => None,
718        }
719    }
720
721    /// Matches a `PredicateKind::Clause` and turns it into a `Clause`, otherwise returns `None`.
722    pub fn as_clause(self) -> Option<Clause<'db>> {
723        match self.kind().skip_binder() {
724            PredicateKind::Clause(..) => Some(self.expect_clause()),
725            _ => None,
726        }
727    }
728
729    /// Assert that the predicate is a clause.
730    pub fn expect_clause(self) -> Clause<'db> {
731        match self.kind().skip_binder() {
732            PredicateKind::Clause(..) => Clause(self),
733            _ => panic!("{self:?} is not a clause"),
734        }
735    }
736}
737
738impl<'db> TypeVisitable<DbInterner<'db>> for Clause<'db> {
739    fn visit_with<V: rustc_type_ir::TypeVisitor<DbInterner<'db>>>(
740        &self,
741        visitor: &mut V,
742    ) -> V::Result {
743        visitor.visit_predicate((*self).as_predicate())
744    }
745}
746
747impl<'db> TypeFoldable<DbInterner<'db>> for Clause<'db> {
748    fn try_fold_with<F: rustc_type_ir::FallibleTypeFolder<DbInterner<'db>>>(
749        self,
750        folder: &mut F,
751    ) -> Result<Self, F::Error> {
752        Ok(folder.try_fold_predicate(self.as_predicate())?.expect_clause())
753    }
754    fn fold_with<F: rustc_type_ir::TypeFolder<DbInterner<'db>>>(self, folder: &mut F) -> Self {
755        folder.fold_predicate(self.as_predicate()).expect_clause()
756    }
757}
758
759impl<'db> IntoKind for Clause<'db> {
760    type Kind = Binder<'db, ClauseKind<'db>>;
761
762    fn kind(self) -> Self::Kind {
763        self.0.kind().map_bound(|pk| match pk {
764            PredicateKind::Clause(kind) => kind,
765            _ => unreachable!(),
766        })
767    }
768}
769
770impl<'db> Clause<'db> {
771    pub fn as_predicate(self) -> Predicate<'db> {
772        self.0
773    }
774}
775
776impl<'db> Elaboratable<DbInterner<'db>> for Clause<'db> {
777    fn predicate(&self) -> <DbInterner<'db> as rustc_type_ir::Interner>::Predicate {
778        self.0
779    }
780
781    fn child(&self, clause: <DbInterner<'db> as rustc_type_ir::Interner>::Clause) -> Self {
782        clause
783    }
784
785    fn child_with_derived_cause(
786        &self,
787        clause: <DbInterner<'db> as rustc_type_ir::Interner>::Clause,
788        _span: <DbInterner<'db> as rustc_type_ir::Interner>::Span,
789        _parent_trait_pred: rustc_type_ir::Binder<
790            DbInterner<'db>,
791            rustc_type_ir::TraitPredicate<DbInterner<'db>>,
792        >,
793        _index: usize,
794    ) -> Self {
795        clause
796    }
797}
798
799impl<'db> UpcastFrom<DbInterner<'db>, ty::Binder<DbInterner<'db>, ty::ClauseKind<DbInterner<'db>>>>
800    for Clause<'db>
801{
802    fn upcast_from(
803        from: ty::Binder<DbInterner<'db>, ty::ClauseKind<DbInterner<'db>>>,
804        interner: DbInterner<'db>,
805    ) -> Self {
806        Clause(from.map_bound(PredicateKind::Clause).upcast(interner))
807    }
808}
809impl<'db> UpcastFrom<DbInterner<'db>, ty::TraitRef<DbInterner<'db>>> for Clause<'db> {
810    fn upcast_from(from: ty::TraitRef<DbInterner<'db>>, interner: DbInterner<'db>) -> Self {
811        Clause(from.upcast(interner))
812    }
813}
814impl<'db> UpcastFrom<DbInterner<'db>, ty::Binder<DbInterner<'db>, ty::TraitRef<DbInterner<'db>>>>
815    for Clause<'db>
816{
817    fn upcast_from(
818        from: ty::Binder<DbInterner<'db>, ty::TraitRef<DbInterner<'db>>>,
819        interner: DbInterner<'db>,
820    ) -> Self {
821        Clause(from.upcast(interner))
822    }
823}
824impl<'db> UpcastFrom<DbInterner<'db>, ty::TraitPredicate<DbInterner<'db>>> for Clause<'db> {
825    fn upcast_from(from: ty::TraitPredicate<DbInterner<'db>>, interner: DbInterner<'db>) -> Self {
826        Clause(from.upcast(interner))
827    }
828}
829impl<'db>
830    UpcastFrom<DbInterner<'db>, ty::Binder<DbInterner<'db>, ty::TraitPredicate<DbInterner<'db>>>>
831    for Clause<'db>
832{
833    fn upcast_from(
834        from: ty::Binder<DbInterner<'db>, ty::TraitPredicate<DbInterner<'db>>>,
835        interner: DbInterner<'db>,
836    ) -> Self {
837        Clause(from.upcast(interner))
838    }
839}
840impl<'db> UpcastFrom<DbInterner<'db>, ty::ProjectionPredicate<DbInterner<'db>>> for Clause<'db> {
841    fn upcast_from(
842        from: ty::ProjectionPredicate<DbInterner<'db>>,
843        interner: DbInterner<'db>,
844    ) -> Self {
845        Clause(from.upcast(interner))
846    }
847}
848impl<'db>
849    UpcastFrom<
850        DbInterner<'db>,
851        ty::Binder<DbInterner<'db>, ty::ProjectionPredicate<DbInterner<'db>>>,
852    > for Clause<'db>
853{
854    fn upcast_from(
855        from: ty::Binder<DbInterner<'db>, ty::ProjectionPredicate<DbInterner<'db>>>,
856        interner: DbInterner<'db>,
857    ) -> Self {
858        Clause(from.upcast(interner))
859    }
860}
861
862impl<'db> rustc_type_ir::inherent::Clause<DbInterner<'db>> for Clause<'db> {
863    fn as_predicate(self) -> <DbInterner<'db> as rustc_type_ir::Interner>::Predicate {
864        self.0
865    }
866
867    fn instantiate_supertrait(
868        self,
869        cx: DbInterner<'db>,
870        trait_ref: rustc_type_ir::Binder<DbInterner<'db>, rustc_type_ir::TraitRef<DbInterner<'db>>>,
871    ) -> Self {
872        tracing::debug!(?self, ?trait_ref);
873        // See the rustc impl for a long comment
874        let bound_pred = self.kind();
875        let pred_bound_vars = bound_pred.bound_vars();
876        let trait_bound_vars = trait_ref.bound_vars();
877        // 1) Self: Bar1<'a, '^0.0> -> Self: Bar1<'a, '^0.1>
878        let shifted_pred =
879            cx.shift_bound_var_indices(trait_bound_vars.len(), bound_pred.skip_binder());
880        // 2) Self: Bar1<'a, '^0.1> -> T: Bar1<'^0.0, '^0.1>
881        let new = EarlyBinder::bind(shifted_pred)
882            .instantiate(cx, trait_ref.skip_binder().args)
883            .skip_norm_wip();
884        // 3) ['x] + ['b] -> ['x, 'b]
885        let bound_vars =
886            BoundVarKinds::new_from_iter(cx, trait_bound_vars.iter().chain(pred_bound_vars.iter()));
887
888        let predicate: Predicate<'db> =
889            ty::Binder::bind_with_vars(PredicateKind::Clause(new), bound_vars).upcast(cx);
890        predicate.expect_clause()
891    }
892}
hir_ty/next_solver/predicate.rs

hir_ty/next_solver/
predicate.rs
