diff options
Diffstat (limited to 'compiler/rustc_trait_selection/src/traits/project.rs')
| -rw-r--r-- | compiler/rustc_trait_selection/src/traits/project.rs | 160 |
1 files changed, 74 insertions, 86 deletions
diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs index fbc7ecced..870ecc2a9 100644 --- a/compiler/rustc_trait_selection/src/traits/project.rs +++ b/compiler/rustc_trait_selection/src/traits/project.rs @@ -31,7 +31,7 @@ use rustc_infer::infer::resolve::OpportunisticRegionResolver; use rustc_infer::traits::ImplSourceBuiltinData; use rustc_middle::traits::select::OverflowError; use rustc_middle::ty::fold::{TypeFoldable, TypeFolder, TypeSuperFoldable}; -use rustc_middle::ty::visit::{MaxUniverse, TypeVisitable}; +use rustc_middle::ty::visit::{MaxUniverse, TypeVisitable, TypeVisitableExt}; use rustc_middle::ty::DefIdTree; use rustc_middle::ty::{self, Term, ToPredicate, Ty, TyCtxt}; use rustc_span::symbol::sym; @@ -53,11 +53,11 @@ pub trait NormalizeExt<'tcx> { /// /// This normalization should be used when the type contains inference variables or the /// projection may be fallible. - fn normalize<T: TypeFoldable<'tcx>>(&self, t: T) -> InferOk<'tcx, T>; + fn normalize<T: TypeFoldable<TyCtxt<'tcx>>>(&self, t: T) -> InferOk<'tcx, T>; } impl<'tcx> NormalizeExt<'tcx> for At<'_, 'tcx> { - fn normalize<T: TypeFoldable<'tcx>>(&self, value: T) -> InferOk<'tcx, T> { + fn normalize<T: TypeFoldable<TyCtxt<'tcx>>>(&self, value: T) -> InferOk<'tcx, T> { let mut selcx = SelectionContext::new(self.infcx); let Normalized { value, obligations } = normalize_with_depth(&mut selcx, self.param_env, self.cause.clone(), 0, value); @@ -90,15 +90,7 @@ enum ProjectionCandidate<'tcx> { /// From an "impl" (or a "pseudo-impl" returned by select) Select(Selection<'tcx>), - ImplTraitInTrait(ImplTraitInTraitCandidate<'tcx>), -} - -#[derive(PartialEq, Eq, Debug)] -enum ImplTraitInTraitCandidate<'tcx> { - // The `impl Trait` from a trait function's default body - Trait, - // A concrete type provided from a trait's `impl Trait` from an impl - Impl(ImplSourceUserDefinedData<'tcx, PredicateObligation<'tcx>>), + ImplTraitInTrait(ImplSourceUserDefinedData<'tcx, PredicateObligation<'tcx>>), } enum ProjectionCandidateSet<'tcx> { @@ -215,7 +207,7 @@ pub(super) fn poly_project_and_unify_type<'cx, 'tcx>( let r = infcx.commit_if_ok(|_snapshot| { let old_universe = infcx.universe(); let placeholder_predicate = - infcx.replace_bound_vars_with_placeholders(obligation.predicate); + infcx.instantiate_binder_with_placeholders(obligation.predicate); let new_universe = infcx.universe(); let placeholder_obligation = obligation.with(infcx.tcx, placeholder_predicate); @@ -294,7 +286,12 @@ fn project_and_unify_type<'cx, 'tcx>( ); obligations.extend(new); - match infcx.at(&obligation.cause, obligation.param_env).eq(normalized, actual) { + match infcx + .at(&obligation.cause, obligation.param_env) + // This is needed to support nested opaque types like `impl Fn() -> impl Trait` + .define_opaque_types(true) + .eq(normalized, actual) + { Ok(InferOk { obligations: inferred_obligations, value: () }) => { obligations.extend(inferred_obligations); ProjectAndUnifyResult::Holds(obligations) @@ -315,7 +312,7 @@ pub(crate) fn normalize_with_depth<'a, 'b, 'tcx, T>( value: T, ) -> Normalized<'tcx, T> where - T: TypeFoldable<'tcx>, + T: TypeFoldable<TyCtxt<'tcx>>, { let mut obligations = Vec::new(); let value = normalize_with_depth_to(selcx, param_env, cause, depth, value, &mut obligations); @@ -332,7 +329,7 @@ pub(crate) fn normalize_with_depth_to<'a, 'b, 'tcx, T>( obligations: &mut Vec<PredicateObligation<'tcx>>, ) -> T where - T: TypeFoldable<'tcx>, + T: TypeFoldable<TyCtxt<'tcx>>, { debug!(obligations.len = obligations.len()); let mut normalizer = AssocTypeNormalizer::new(selcx, param_env, cause, depth, obligations); @@ -352,7 +349,7 @@ pub(crate) fn try_normalize_with_depth_to<'a, 'b, 'tcx, T>( obligations: &mut Vec<PredicateObligation<'tcx>>, ) -> T where - T: TypeFoldable<'tcx>, + T: TypeFoldable<TyCtxt<'tcx>>, { debug!(obligations.len = obligations.len()); let mut normalizer = AssocTypeNormalizer::new_without_eager_inference_replacement( @@ -368,7 +365,10 @@ where result } -pub(crate) fn needs_normalization<'tcx, T: TypeVisitable<'tcx>>(value: &T, reveal: Reveal) -> bool { +pub(crate) fn needs_normalization<'tcx, T: TypeVisitable<TyCtxt<'tcx>>>( + value: &T, + reveal: Reveal, +) -> bool { match reveal { Reveal::UserFacing => value .has_type_flags(ty::TypeFlags::HAS_TY_PROJECTION | ty::TypeFlags::HAS_CT_PROJECTION), @@ -430,7 +430,7 @@ impl<'a, 'b, 'tcx> AssocTypeNormalizer<'a, 'b, 'tcx> { } } - fn fold<T: TypeFoldable<'tcx>>(&mut self, value: T) -> T { + fn fold<T: TypeFoldable<TyCtxt<'tcx>>>(&mut self, value: T) -> T { let value = self.selcx.infcx.resolve_vars_if_possible(value); debug!(?value); @@ -448,12 +448,12 @@ impl<'a, 'b, 'tcx> AssocTypeNormalizer<'a, 'b, 'tcx> { } } -impl<'a, 'b, 'tcx> TypeFolder<'tcx> for AssocTypeNormalizer<'a, 'b, 'tcx> { - fn tcx<'c>(&'c self) -> TyCtxt<'tcx> { +impl<'a, 'b, 'tcx> TypeFolder<TyCtxt<'tcx>> for AssocTypeNormalizer<'a, 'b, 'tcx> { + fn interner(&self) -> TyCtxt<'tcx> { self.selcx.tcx() } - fn fold_binder<T: TypeFoldable<'tcx>>( + fn fold_binder<T: TypeFoldable<TyCtxt<'tcx>>>( &mut self, t: ty::Binder<'tcx, T>, ) -> ty::Binder<'tcx, T> { @@ -503,7 +503,7 @@ impl<'a, 'b, 'tcx> TypeFolder<'tcx> for AssocTypeNormalizer<'a, 'b, 'tcx> { Reveal::UserFacing => ty.super_fold_with(self), Reveal::All => { - let recursion_limit = self.tcx().recursion_limit(); + let recursion_limit = self.interner().recursion_limit(); if !recursion_limit.value_within_limit(self.depth) { self.selcx.infcx.err_ctxt().report_overflow_error( &ty, @@ -514,8 +514,8 @@ impl<'a, 'b, 'tcx> TypeFolder<'tcx> for AssocTypeNormalizer<'a, 'b, 'tcx> { } let substs = substs.fold_with(self); - let generic_ty = self.tcx().bound_type_of(def_id); - let concrete_ty = generic_ty.subst(self.tcx(), substs); + let generic_ty = self.interner().type_of(def_id); + let concrete_ty = generic_ty.subst(self.interner(), substs); self.depth += 1; let folded_ty = self.fold_ty(concrete_ty); self.depth -= 1; @@ -672,7 +672,12 @@ pub struct BoundVarReplacer<'me, 'tcx> { /// /// FIXME(@lcnr): We may even consider experimenting with eagerly replacing bound vars during /// normalization as well, at which point this function will be unnecessary and can be removed. -pub fn with_replaced_escaping_bound_vars<'a, 'tcx, T: TypeFoldable<'tcx>, R: TypeFoldable<'tcx>>( +pub fn with_replaced_escaping_bound_vars< + 'a, + 'tcx, + T: TypeFoldable<TyCtxt<'tcx>>, + R: TypeFoldable<TyCtxt<'tcx>>, +>( infcx: &'a InferCtxt<'tcx>, universe_indices: &'a mut Vec<Option<ty::UniverseIndex>>, value: T, @@ -698,7 +703,7 @@ pub fn with_replaced_escaping_bound_vars<'a, 'tcx, T: TypeFoldable<'tcx>, R: Typ impl<'me, 'tcx> BoundVarReplacer<'me, 'tcx> { /// Returns `Some` if we *were* able to replace bound vars. If there are any bound vars that /// use a binding level above `universe_indices.len()`, we fail. - pub fn replace_bound_vars<T: TypeFoldable<'tcx>>( + pub fn replace_bound_vars<T: TypeFoldable<TyCtxt<'tcx>>>( infcx: &'me InferCtxt<'tcx>, universe_indices: &'me mut Vec<Option<ty::UniverseIndex>>, value: T, @@ -740,12 +745,12 @@ impl<'me, 'tcx> BoundVarReplacer<'me, 'tcx> { } } -impl<'tcx> TypeFolder<'tcx> for BoundVarReplacer<'_, 'tcx> { - fn tcx<'b>(&'b self) -> TyCtxt<'tcx> { +impl<'tcx> TypeFolder<TyCtxt<'tcx>> for BoundVarReplacer<'_, 'tcx> { + fn interner(&self) -> TyCtxt<'tcx> { self.infcx.tcx } - fn fold_binder<T: TypeFoldable<'tcx>>( + fn fold_binder<T: TypeFoldable<TyCtxt<'tcx>>>( &mut self, t: ty::Binder<'tcx, T>, ) -> ty::Binder<'tcx, T> { @@ -767,7 +772,7 @@ impl<'tcx> TypeFolder<'tcx> for BoundVarReplacer<'_, 'tcx> { let universe = self.universe_for(debruijn); let p = ty::PlaceholderRegion { universe, name: br.kind }; self.mapped_regions.insert(p, br); - self.infcx.tcx.mk_region(ty::RePlaceholder(p)) + self.infcx.tcx.mk_re_placeholder(p) } _ => r, } @@ -783,9 +788,9 @@ impl<'tcx> TypeFolder<'tcx> for BoundVarReplacer<'_, 'tcx> { } ty::Bound(debruijn, bound_ty) if debruijn >= self.current_index => { let universe = self.universe_for(debruijn); - let p = ty::PlaceholderType { universe, name: bound_ty.var }; + let p = ty::PlaceholderType { universe, name: bound_ty.kind }; self.mapped_types.insert(p, bound_ty); - self.infcx.tcx.mk_ty(ty::Placeholder(p)) + self.infcx.tcx.mk_placeholder(p) } _ if t.has_vars_bound_at_or_above(self.current_index) => t.super_fold_with(self), _ => t, @@ -826,7 +831,7 @@ pub struct PlaceholderReplacer<'me, 'tcx> { } impl<'me, 'tcx> PlaceholderReplacer<'me, 'tcx> { - pub fn replace_placeholders<T: TypeFoldable<'tcx>>( + pub fn replace_placeholders<T: TypeFoldable<TyCtxt<'tcx>>>( infcx: &'me InferCtxt<'tcx>, mapped_regions: BTreeMap<ty::PlaceholderRegion, ty::BoundRegion>, mapped_types: BTreeMap<ty::PlaceholderType, ty::BoundTy>, @@ -846,12 +851,12 @@ impl<'me, 'tcx> PlaceholderReplacer<'me, 'tcx> { } } -impl<'tcx> TypeFolder<'tcx> for PlaceholderReplacer<'_, 'tcx> { - fn tcx<'b>(&'b self) -> TyCtxt<'tcx> { +impl<'tcx> TypeFolder<TyCtxt<'tcx>> for PlaceholderReplacer<'_, 'tcx> { + fn interner(&self) -> TyCtxt<'tcx> { self.infcx.tcx } - fn fold_binder<T: TypeFoldable<'tcx>>( + fn fold_binder<T: TypeFoldable<TyCtxt<'tcx>>>( &mut self, t: ty::Binder<'tcx, T>, ) -> ty::Binder<'tcx, T> { @@ -888,7 +893,7 @@ impl<'tcx> TypeFolder<'tcx> for PlaceholderReplacer<'_, 'tcx> { let db = ty::DebruijnIndex::from_usize( self.universe_indices.len() - index + self.current_index.as_usize() - 1, ); - self.tcx().mk_region(ty::ReLateBound(db, *replace_var)) + self.interner().mk_re_late_bound(db, *replace_var) } None => r1, } @@ -915,7 +920,7 @@ impl<'tcx> TypeFolder<'tcx> for PlaceholderReplacer<'_, 'tcx> { let db = ty::DebruijnIndex::from_usize( self.universe_indices.len() - index + self.current_index.as_usize() - 1, ); - self.tcx().mk_ty(ty::Bound(db, *replace_var)) + self.interner().mk_bound(db, *replace_var) } None => ty, } @@ -939,7 +944,7 @@ impl<'tcx> TypeFolder<'tcx> for PlaceholderReplacer<'_, 'tcx> { let db = ty::DebruijnIndex::from_usize( self.universe_indices.len() - index + self.current_index.as_usize() - 1, ); - self.tcx().mk_const(ty::ConstKind::Bound(db, *replace_var), ct.ty()) + self.interner().mk_const(ty::ConstKind::Bound(db, *replace_var), ct.ty()) } None => ct, } @@ -1170,7 +1175,7 @@ fn opt_normalize_projection_type<'a, 'b, 'tcx>( /// paths you want to take. To make things worse, it was possible for /// cycles to arise, where you basically had a setup like `<MyType<$0> /// as Trait>::Foo == $0`. Here, normalizing `<MyType<$0> as -/// Trait>::Foo> to `[type error]` would lead to an obligation of +/// Trait>::Foo>` to `[type error]` would lead to an obligation of /// `<MyType<[type error]> as Trait>::Foo`. We are supposed to report /// an error for this obligation, but we legitimately should not, /// because it contains `[type error]`. Yuck! (See issue #29857 for @@ -1208,8 +1213,8 @@ struct Progress<'tcx> { } impl<'tcx> Progress<'tcx> { - fn error(tcx: TyCtxt<'tcx>) -> Self { - Progress { term: tcx.ty_error().into(), obligations: vec![] } + fn error(tcx: TyCtxt<'tcx>, guar: ErrorGuaranteed) -> Self { + Progress { term: tcx.ty_error(guar).into(), obligations: vec![] } } fn with_addl_obligations(mut self, mut obligations: Vec<PredicateObligation<'tcx>>) -> Self { @@ -1235,8 +1240,8 @@ fn project<'cx, 'tcx>( ))); } - if obligation.predicate.references_error() { - return Ok(Projected::Progress(Progress::error(selcx.tcx()))); + if let Err(guar) = obligation.predicate.error_reported() { + return Ok(Projected::Progress(Progress::error(selcx.tcx(), guar))); } let mut candidates = ProjectionCandidateSet::None; @@ -1292,17 +1297,6 @@ fn assemble_candidate_for_impl_trait_in_trait<'cx, 'tcx>( let tcx = selcx.tcx(); if tcx.def_kind(obligation.predicate.def_id) == DefKind::ImplTraitPlaceholder { let trait_fn_def_id = tcx.impl_trait_in_trait_parent(obligation.predicate.def_id); - // If we are trying to project an RPITIT with trait's default `Self` parameter, - // then we must be within a default trait body. - if obligation.predicate.self_ty() - == ty::InternalSubsts::identity_for_item(tcx, obligation.predicate.def_id).type_at(0) - && tcx.associated_item(trait_fn_def_id).defaultness(tcx).has_value() - { - candidate_set.push_candidate(ProjectionCandidate::ImplTraitInTrait( - ImplTraitInTraitCandidate::Trait, - )); - return; - } let trait_def_id = tcx.parent(trait_fn_def_id); let trait_substs = @@ -1313,23 +1307,21 @@ fn assemble_candidate_for_impl_trait_in_trait<'cx, 'tcx>( let _ = selcx.infcx.commit_if_ok(|_| { match selcx.select(&obligation.with(tcx, trait_predicate)) { Ok(Some(super::ImplSource::UserDefined(data))) => { - candidate_set.push_candidate(ProjectionCandidate::ImplTraitInTrait( - ImplTraitInTraitCandidate::Impl(data), - )); + candidate_set.push_candidate(ProjectionCandidate::ImplTraitInTrait(data)); Ok(()) } Ok(None) => { candidate_set.mark_ambiguous(); - return Err(()); + Err(()) } Ok(Some(_)) => { // Don't know enough about the impl to provide a useful signature - return Err(()); + Err(()) } Err(e) => { debug!(error = ?e, "selection error"); candidate_set.mark_error(e); - return Err(()); + Err(()) } } }); @@ -1605,6 +1597,7 @@ fn assemble_candidates_from_impls<'cx, 'tcx>( | ty::Closure(..) | ty::Generator(..) | ty::GeneratorWitness(..) + | ty::GeneratorWitnessMIR(..) | ty::Never | ty::Tuple(..) // Integers and floats always have `u8` as their discriminant. @@ -1654,6 +1647,7 @@ fn assemble_candidates_from_impls<'cx, 'tcx>( | ty::Closure(..) | ty::Generator(..) | ty::GeneratorWitness(..) + | ty::GeneratorWitnessMIR(..) | ty::Never // Extern types have unit metadata, according to RFC 2850 | ty::Foreign(_) @@ -1775,18 +1769,9 @@ fn confirm_candidate<'cx, 'tcx>( ProjectionCandidate::Select(impl_source) => { confirm_select_candidate(selcx, obligation, impl_source) } - ProjectionCandidate::ImplTraitInTrait(ImplTraitInTraitCandidate::Impl(data)) => { + ProjectionCandidate::ImplTraitInTrait(data) => { confirm_impl_trait_in_trait_candidate(selcx, obligation, data) } - // If we're projecting an RPITIT for a default trait body, that's just - // the same def-id, but as an opaque type (with regular RPIT semantics). - ProjectionCandidate::ImplTraitInTrait(ImplTraitInTraitCandidate::Trait) => Progress { - term: selcx - .tcx() - .mk_opaque(obligation.predicate.def_id, obligation.predicate.substs) - .into(), - obligations: vec![], - }, }; // When checking for cycle during evaluation, we compare predicates with @@ -1921,7 +1906,7 @@ fn confirm_builtin_candidate<'cx, 'tcx>( ) -> Progress<'tcx> { let tcx = selcx.tcx(); let self_ty = obligation.predicate.self_ty(); - let substs = tcx.mk_substs([self_ty.into()].iter()); + let substs = tcx.mk_substs(&[self_ty.into()]); let lang_items = tcx.lang_items(); let item_def_id = obligation.predicate.def_id; let trait_def_id = tcx.trait_of_item(item_def_id).unwrap(); @@ -2044,7 +2029,7 @@ fn confirm_param_env_candidate<'cx, 'tcx>( let cause = &obligation.cause; let param_env = obligation.param_env; - let cache_entry = infcx.replace_bound_vars_with_fresh_vars( + let cache_entry = infcx.instantiate_binder_with_fresh_vars( cause.span, LateBoundRegionConversionTime::HigherRankedType, poly_cache_entry, @@ -2112,8 +2097,9 @@ fn confirm_impl_candidate<'cx, 'tcx>( let trait_def_id = tcx.trait_id_of_impl(impl_def_id).unwrap(); let param_env = obligation.param_env; - let Ok(assoc_ty) = specialization_graph::assoc_def(tcx, impl_def_id, assoc_item_id) else { - return Progress { term: tcx.ty_error().into(), obligations: nested }; + let assoc_ty = match specialization_graph::assoc_def(tcx, impl_def_id, assoc_item_id) { + Ok(assoc_ty) => assoc_ty, + Err(guar) => return Progress::error(tcx, guar), }; if !assoc_ty.item.defaultness(tcx).has_value() { @@ -2125,7 +2111,7 @@ fn confirm_impl_candidate<'cx, 'tcx>( "confirm_impl_candidate: no associated type {:?} for {:?}", assoc_ty.item.name, obligation.predicate ); - return Progress { term: tcx.ty_error().into(), obligations: nested }; + return Progress { term: tcx.ty_error_misc().into(), obligations: nested }; } // If we're trying to normalize `<Vec<u32> as X>::A<S>` using //`impl<T> X for Vec<T> { type A<Y> = Box<Y>; }`, then: @@ -2136,7 +2122,7 @@ fn confirm_impl_candidate<'cx, 'tcx>( let substs = obligation.predicate.substs.rebase_onto(tcx, trait_def_id, substs); let substs = translate_substs(selcx.infcx, param_env, impl_def_id, substs, assoc_ty.defining_node); - let ty = tcx.bound_type_of(assoc_ty.item.def_id); + let ty = tcx.type_of(assoc_ty.item.def_id); let is_const = matches!(tcx.def_kind(assoc_ty.item.def_id), DefKind::AssocConst); let term: ty::EarlyBinder<ty::Term<'tcx>> = if is_const { let identity_substs = @@ -2147,7 +2133,7 @@ fn confirm_impl_candidate<'cx, 'tcx>( } else { ty.map_bound(|ty| ty.into()) }; - if !check_substs_compatible(tcx, &assoc_ty.item, substs) { + if !check_substs_compatible(tcx, assoc_ty.item, substs) { let err = tcx.ty_error_with_message( obligation.cause.span, "impl item and trait item have different parameters", @@ -2162,7 +2148,7 @@ fn confirm_impl_candidate<'cx, 'tcx>( // Verify that the trait item and its implementation have compatible substs lists fn check_substs_compatible<'tcx>( tcx: TyCtxt<'tcx>, - assoc_item: &ty::AssocItem, + assoc_item: ty::AssocItem, substs: ty::SubstsRef<'tcx>, ) -> bool { fn check_substs_compatible_inner<'tcx>( @@ -2209,11 +2195,13 @@ fn confirm_impl_trait_in_trait_candidate<'tcx>( let mut obligations = data.nested; let trait_fn_def_id = tcx.impl_trait_in_trait_parent(obligation.predicate.def_id); - let Ok(leaf_def) = specialization_graph::assoc_def(tcx, data.impl_def_id, trait_fn_def_id) else { - return Progress { term: tcx.ty_error().into(), obligations }; + let leaf_def = match specialization_graph::assoc_def(tcx, data.impl_def_id, trait_fn_def_id) { + Ok(assoc_ty) => assoc_ty, + Err(guar) => return Progress::error(tcx, guar), }; - if !leaf_def.item.defaultness(tcx).has_value() { - return Progress { term: tcx.ty_error().into(), obligations }; + // We don't support specialization for RPITITs anyways... yet. + if !leaf_def.is_final() { + return Progress { term: tcx.ty_error_misc().into(), obligations }; } // Use the default `impl Trait` for the trait, e.g., for a default trait body @@ -2236,7 +2224,7 @@ fn confirm_impl_trait_in_trait_candidate<'tcx>( leaf_def.defining_node, ); - if !check_substs_compatible(tcx, &leaf_def.item, impl_fn_substs) { + if !check_substs_compatible(tcx, leaf_def.item, impl_fn_substs) { let err = tcx.ty_error_with_message( obligation.cause.span, "impl method and trait method have different parameters", @@ -2284,7 +2272,7 @@ fn confirm_impl_trait_in_trait_candidate<'tcx>( obligation.recursion_depth + 1, tcx.bound_return_position_impl_trait_in_trait_tys(impl_fn_def_id) .map_bound(|tys| { - tys.map_or_else(|_| tcx.ty_error(), |tys| tys[&obligation.predicate.def_id]) + tys.map_or_else(|guar| tcx.ty_error(guar), |tys| tys[&obligation.predicate.def_id]) }) .subst(tcx, impl_fn_substs), &mut obligations, |