diff options
Diffstat (limited to 'compiler/rustc_trait_selection/src/traits/select/confirmation.rs')
| -rw-r--r-- | compiler/rustc_trait_selection/src/traits/select/confirmation.rs | 214 |
1 files changed, 121 insertions, 93 deletions
diff --git a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs index ed22058c6..fda415155 100644 --- a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs +++ b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs @@ -19,14 +19,18 @@ use rustc_span::def_id::DefId; use crate::traits::project::{normalize_with_depth, normalize_with_depth_to}; use crate::traits::util::{self, closure_trait_ref_and_return_type, predicate_for_trait_def}; +use crate::traits::vtable::{ + count_own_vtable_entries, prepare_vtable_segments, vtable_trait_first_method_offset, + VtblSegment, +}; use crate::traits::{ BuiltinDerivedObligation, ImplDerivedObligation, ImplDerivedObligationCause, ImplSource, ImplSourceAutoImplData, ImplSourceBuiltinData, ImplSourceClosureData, - ImplSourceConstDestructData, ImplSourceDiscriminantKindData, ImplSourceFnPointerData, - ImplSourceGeneratorData, ImplSourceObjectData, ImplSourcePointeeData, ImplSourceTraitAliasData, + ImplSourceConstDestructData, ImplSourceFnPointerData, ImplSourceFutureData, + ImplSourceGeneratorData, ImplSourceObjectData, ImplSourceTraitAliasData, ImplSourceTraitUpcastingData, ImplSourceUserDefinedData, Normalized, ObjectCastObligation, Obligation, ObligationCause, OutputTypeParameterMismatch, PredicateObligation, Selection, - SelectionError, TraitNotObjectSafe, TraitObligation, Unimplemented, VtblSegment, + SelectionError, TraitNotObjectSafe, TraitObligation, Unimplemented, }; use super::BuiltinImplConditions; @@ -89,17 +93,16 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { ImplSource::Generator(vtable_generator) } + FutureCandidate => { + let vtable_future = self.confirm_future_candidate(obligation)?; + ImplSource::Future(vtable_future) + } + FnPointerCandidate { .. } => { let data = self.confirm_fn_pointer_candidate(obligation)?; ImplSource::FnPointer(data) } - DiscriminantKindCandidate => { - ImplSource::DiscriminantKind(ImplSourceDiscriminantKindData) - } - - PointeeCandidate => ImplSource::Pointee(ImplSourcePointeeData), - TraitAliasCandidate => { let data = self.confirm_trait_alias_candidate(obligation); ImplSource::TraitAlias(data) @@ -148,7 +151,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { let trait_predicate = self.infcx.shallow_resolve(obligation.predicate); let placeholder_trait_predicate = - self.infcx().replace_bound_vars_with_placeholders(trait_predicate).trait_ref; + self.infcx.replace_bound_vars_with_placeholders(trait_predicate).trait_ref; let placeholder_self_ty = placeholder_trait_predicate.self_ty(); let placeholder_trait_predicate = ty::Binder::dummy(placeholder_trait_predicate); let (def_id, substs) = match *placeholder_self_ty.kind() { @@ -194,6 +197,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { &mut obligations, ); obligations.push(Obligation::with_depth( + self.tcx(), obligation.cause.clone(), obligation.recursion_depth + 1, obligation.param_env, @@ -482,11 +486,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { super_trait, &mut nested, ); - nested.push(Obligation::new( - obligation.cause.clone(), - obligation.param_env, - normalized_super_trait, - )); + nested.push(obligation.with(tcx, normalized_super_trait)); } let assoc_types: Vec<_> = tcx @@ -555,13 +555,13 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { GenericParamDefKind::Const { .. } => { let bound_var = ty::BoundVariableKind::Const; bound_vars.push(bound_var); - tcx.mk_const(ty::ConstS { - ty: tcx.type_of(param.def_id), - kind: ty::ConstKind::Bound( + tcx.mk_const( + ty::ConstKind::Bound( ty::INNERMOST, ty::BoundVar::from_usize(bound_vars.len() - 1), ), - }) + tcx.type_of(param.def_id), + ) .into() } }); @@ -581,17 +581,13 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { subst_bound, &mut nested, ); - nested.push(Obligation::new( - obligation.cause.clone(), - obligation.param_env, - normalized_bound, - )); + nested.push(obligation.with(tcx, normalized_bound)); } } debug!(?nested, "object nested obligations"); - let vtable_base = super::super::vtable_trait_first_method_offset( + let vtable_base = vtable_trait_first_method_offset( tcx, (unnormalized_upcast_trait_ref, ty::Binder::dummy(object_trait_ref)), ); @@ -606,8 +602,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { { debug!(?obligation, "confirm_fn_pointer_candidate"); - // Okay to skip binder; it is reintroduced below. - let self_ty = self.infcx.shallow_resolve(obligation.self_ty().skip_binder()); + let self_ty = self + .infcx + .shallow_resolve(obligation.self_ty().no_bound_vars()) + .expect("fn pointer should not capture bound vars from predicate"); let sig = self_ty.fn_sig(self.tcx()); let trait_ref = closure_trait_ref_and_return_type( self.tcx(), @@ -622,15 +620,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { // Confirm the `type Output: Sized;` bound that is present on `FnOnce` let cause = obligation.derived_cause(BuiltinDerivedObligation); - // The binder on the Fn obligation is "less" important than the one on - // the signature, as evidenced by how we treat it during projection. - // The safe thing to do here is to liberate it, though, which should - // have no worse effect than skipping the binder here. - let liberated_fn_ty = - self.infcx.replace_bound_vars_with_placeholders(obligation.predicate.rebind(self_ty)); - let output_ty = self - .infcx - .replace_bound_vars_with_placeholders(liberated_fn_ty.fn_sig(self.tcx()).output()); + let output_ty = self.infcx.replace_bound_vars_with_placeholders(sig.output()); let output_ty = normalize_with_depth_to( self, obligation.param_env, @@ -639,15 +629,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { output_ty, &mut nested, ); - let tr = ty::Binder::dummy(ty::TraitRef::new( - self.tcx().require_lang_item(LangItem::Sized, None), - self.tcx().mk_substs_trait(output_ty, &[]), - )); - nested.push(Obligation::new( - cause, - obligation.param_env, - tr.to_poly_trait_predicate().to_predicate(self.tcx()), - )); + let tr = + ty::Binder::dummy(self.tcx().at(cause.span).mk_trait_ref(LangItem::Sized, [output_ty])); + nested.push(Obligation::new(self.infcx.tcx, cause, obligation.param_env, tr)); Ok(ImplSourceFnPointerData { fn_ty: self_ty, nested }) } @@ -659,7 +643,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { debug!(?obligation, "confirm_trait_alias_candidate"); let alias_def_id = obligation.predicate.def_id(); - let predicate = self.infcx().replace_bound_vars_with_placeholders(obligation.predicate); + let predicate = self.infcx.replace_bound_vars_with_placeholders(obligation.predicate); let trait_ref = predicate.trait_ref; let trait_def_id = trait_ref.def_id; let substs = trait_ref.substs; @@ -693,7 +677,24 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { debug!(?obligation, ?generator_def_id, ?substs, "confirm_generator_candidate"); - let trait_ref = self.generator_trait_ref_unnormalized(obligation, substs); + let gen_sig = substs.as_generator().poly_sig(); + + // NOTE: The self-type is a generator type and hence is + // in fact unparameterized (or at least does not reference any + // regions bound in the obligation). + let self_ty = obligation + .predicate + .self_ty() + .no_bound_vars() + .expect("unboxed closure type should not capture bound vars from the predicate"); + + let trait_ref = super::util::generator_trait_ref_and_outputs( + self.tcx(), + obligation.predicate.def_id(), + self_ty, + gen_sig, + ) + .map_bound(|(trait_ref, ..)| trait_ref); let nested = self.confirm_poly_trait_refs(obligation, trait_ref)?; debug!(?trait_ref, ?nested, "generator candidate obligations"); @@ -701,6 +702,36 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { Ok(ImplSourceGeneratorData { generator_def_id, substs, nested }) } + fn confirm_future_candidate( + &mut self, + obligation: &TraitObligation<'tcx>, + ) -> Result<ImplSourceFutureData<'tcx, PredicateObligation<'tcx>>, SelectionError<'tcx>> { + // Okay to skip binder because the substs on generator types never + // touch bound regions, they just capture the in-scope + // type/region parameters. + let self_ty = self.infcx.shallow_resolve(obligation.self_ty().skip_binder()); + let ty::Generator(generator_def_id, substs, _) = *self_ty.kind() else { + bug!("closure candidate for non-closure {:?}", obligation); + }; + + debug!(?obligation, ?generator_def_id, ?substs, "confirm_future_candidate"); + + let gen_sig = substs.as_generator().poly_sig(); + + let trait_ref = super::util::future_trait_ref_and_outputs( + self.tcx(), + obligation.predicate.def_id(), + obligation.predicate.no_bound_vars().expect("future has no bound vars").self_ty(), + gen_sig, + ) + .map_bound(|(trait_ref, ..)| trait_ref); + + let nested = self.confirm_poly_trait_refs(obligation, trait_ref)?; + debug!(?trait_ref, ?nested, "future candidate obligations"); + + Ok(ImplSourceFutureData { generator_def_id, substs, nested }) + } + #[instrument(skip(self), level = "debug")] fn confirm_closure_candidate( &mut self, @@ -708,7 +739,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { ) -> Result<ImplSourceClosureData<'tcx, PredicateObligation<'tcx>>, SelectionError<'tcx>> { let kind = self .tcx() - .fn_trait_kind_from_lang_item(obligation.predicate.def_id()) + .fn_trait_kind_from_def_id(obligation.predicate.def_id()) .unwrap_or_else(|| bug!("closure candidate for non-fn trait {:?}", obligation)); // Okay to skip binder because the substs on closure types never @@ -727,11 +758,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { // FIXME: Chalk if !self.tcx().sess.opts.unstable_opts.chalk { - nested.push(Obligation::new( - obligation.cause.clone(), - obligation.param_env, - ty::Binder::dummy(ty::PredicateKind::ClosureKind(closure_def_id, substs, kind)) - .to_predicate(self.tcx()), + nested.push(obligation.with( + self.tcx(), + ty::Binder::dummy(ty::PredicateKind::ClosureKind(closure_def_id, substs, kind)), )); } @@ -813,9 +842,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { let upcast_trait_ref; match (source.kind(), target.kind()) { // TraitA+Kx+'a -> TraitB+Ky+'b (trait upcasting coercion). - (&ty::Dynamic(ref data_a, r_a, repr_a), &ty::Dynamic(ref data_b, r_b, repr_b)) - if repr_a == repr_b => - { + ( + &ty::Dynamic(ref data_a, r_a, repr_a @ ty::Dyn), + &ty::Dynamic(ref data_b, r_b, ty::Dyn), + ) => { // See `assemble_candidates_for_unsizing` for more info. // We already checked the compatibility of auto traits within `assemble_candidates_for_unsizing`. let principal_a = data_a.principal().unwrap(); @@ -841,7 +871,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { .map(ty::Binder::dummy), ); let existential_predicates = tcx.mk_poly_existential_predicates(iter); - let source_trait = tcx.mk_dynamic(existential_predicates, r_b, repr_b); + let source_trait = tcx.mk_dynamic(existential_predicates, r_b, repr_a); // Require that the traits involved in this upcast are **equal**; // only the **lifetime bound** is changed. @@ -860,10 +890,11 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { ); let outlives = ty::OutlivesPredicate(r_a, r_b); nested.push(Obligation::with_depth( + tcx, cause, obligation.recursion_depth + 1, obligation.param_env, - obligation.predicate.rebind(outlives).to_predicate(tcx), + obligation.predicate.rebind(outlives), )); } _ => bug!(), @@ -877,7 +908,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { vptr_offset += TyCtxt::COMMON_VTABLE_ENTRIES.len(); } VtblSegment::TraitOwnEntries { trait_ref, emit_vptr } => { - vptr_offset += util::count_own_vtable_entries(tcx, trait_ref); + vptr_offset += count_own_vtable_entries(tcx, trait_ref); if trait_ref == upcast_trait_ref { if emit_vptr { return ControlFlow::Break(Some(vptr_offset)); @@ -896,8 +927,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { }; let vtable_vptr_slot = - super::super::prepare_vtable_segments(tcx, source_trait_ref, vtable_segment_callback) - .unwrap(); + prepare_vtable_segments(tcx, source_trait_ref, vtable_segment_callback).unwrap(); Ok(ImplSourceTraitUpcastingData { upcast_trait_ref, vtable_vptr_slot, nested }) } @@ -919,7 +949,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { let mut nested = vec![]; match (source.kind(), target.kind()) { // Trait+Kx+'a -> Trait+Ky+'b (auto traits and lifetime subtyping). - (&ty::Dynamic(ref data_a, r_a, ty::Dyn), &ty::Dynamic(ref data_b, r_b, ty::Dyn)) => { + (&ty::Dynamic(ref data_a, r_a, dyn_a), &ty::Dynamic(ref data_b, r_b, dyn_b)) + if dyn_a == dyn_b => + { // See `assemble_candidates_for_unsizing` for more info. // We already checked the compatibility of auto traits within `assemble_candidates_for_unsizing`. let iter = data_a @@ -938,7 +970,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { .map(ty::Binder::dummy), ); let existential_predicates = tcx.mk_poly_existential_predicates(iter); - let source_trait = tcx.mk_dynamic(existential_predicates, r_b, ty::Dyn); + let source_trait = tcx.mk_dynamic(existential_predicates, r_b, dyn_a); // Require that the traits involved in this upcast are **equal**; // only the **lifetime bound** is changed. @@ -957,10 +989,11 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { ); let outlives = ty::OutlivesPredicate(r_a, r_b); nested.push(Obligation::with_depth( + tcx, cause, obligation.recursion_depth + 1, obligation.param_env, - obligation.predicate.rebind(outlives).to_predicate(tcx), + obligation.predicate.rebind(outlives), )); } @@ -979,6 +1012,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { let predicate_to_obligation = |predicate| { Obligation::with_depth( + tcx, cause.clone(), obligation.recursion_depth + 1, obligation.param_env, @@ -999,10 +1033,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { ); // We can only make objects from sized types. - let tr = ty::Binder::dummy(ty::TraitRef::new( - tcx.require_lang_item(LangItem::Sized, None), - tcx.mk_substs_trait(source, &[]), - )); + let tr = + ty::Binder::dummy(tcx.at(cause.span).mk_trait_ref(LangItem::Sized, [source])); nested.push(predicate_to_obligation(tr.without_const().to_predicate(tcx))); // If the type is `Foo + 'a`, ensure that the type @@ -1108,8 +1140,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { obligation.cause.clone(), obligation.predicate.def_id(), obligation.recursion_depth + 1, - source_tail, - &[target_tail.into()], + [source_tail, target_tail], )); } @@ -1139,13 +1170,12 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { obligation.cause.clone(), obligation.predicate.def_id(), obligation.recursion_depth + 1, - a_last, - &[b_last.into()], + [a_last, b_last], ) })); } - _ => bug!(), + _ => bug!("source: {source}, target: {target}"), }; Ok(ImplSourceBuiltinData { nested }) @@ -1255,20 +1285,19 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { obligation.param_env, cause.clone(), obligation.recursion_depth + 1, - self_ty - .rebind(ty::TraitPredicate { - trait_ref: ty::TraitRef { - def_id: self.tcx().require_lang_item(LangItem::Destruct, None), - substs: self.tcx().mk_substs_trait(nested_ty, &[]), - }, - constness: ty::BoundConstness::ConstIfConst, - polarity: ty::ImplPolarity::Positive, - }) - .to_predicate(tcx), + self_ty.rebind(ty::TraitPredicate { + trait_ref: self + .tcx() + .at(cause.span) + .mk_trait_ref(LangItem::Destruct, [nested_ty]), + constness: ty::BoundConstness::ConstIfConst, + polarity: ty::ImplPolarity::Positive, + }), &mut nested, ); nested.push(Obligation::with_depth( + tcx, cause.clone(), obligation.recursion_depth + 1, obligation.param_env, @@ -1280,18 +1309,17 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { // since it's either not `const Drop` (and we raise an error during selection), // or it's an ADT (and we need to check for a custom impl during selection) _ => { - let predicate = self_ty - .rebind(ty::TraitPredicate { - trait_ref: ty::TraitRef { - def_id: self.tcx().require_lang_item(LangItem::Destruct, None), - substs: self.tcx().mk_substs_trait(nested_ty, &[]), - }, - constness: ty::BoundConstness::ConstIfConst, - polarity: ty::ImplPolarity::Positive, - }) - .to_predicate(tcx); + let predicate = self_ty.rebind(ty::TraitPredicate { + trait_ref: self + .tcx() + .at(cause.span) + .mk_trait_ref(LangItem::Destruct, [nested_ty]), + constness: ty::BoundConstness::ConstIfConst, + polarity: ty::ImplPolarity::Positive, + }); nested.push(Obligation::with_depth( + tcx, cause.clone(), obligation.recursion_depth + 1, obligation.param_env, |