diff options
Diffstat (limited to 'compiler/rustc_hir_analysis/src/check/compare_impl_item.rs')
| -rw-r--r-- | compiler/rustc_hir_analysis/src/check/compare_impl_item.rs | 272 |
1 files changed, 190 insertions, 82 deletions
diff --git a/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs b/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs index 8bf1e0e84..22e576e34 100644 --- a/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs +++ b/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs @@ -19,12 +19,13 @@ use rustc_middle::ty::{ self, InternalSubsts, Ty, TypeFoldable, TypeFolder, TypeSuperFoldable, TypeVisitableExt, }; use rustc_middle::ty::{GenericParamDefKind, ToPredicate, TyCtxt}; -use rustc_span::Span; +use rustc_span::{Span, DUMMY_SP}; use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt; use rustc_trait_selection::traits::outlives_bounds::InferCtxtExt as _; use rustc_trait_selection::traits::{ self, ObligationCause, ObligationCauseCode, ObligationCtxt, Reveal, }; +use std::borrow::Cow; use std::iter; /// Checks that a method from an impl conforms to the signature of @@ -44,12 +45,7 @@ pub(super) fn compare_impl_method<'tcx>( debug!("compare_impl_method(impl_trait_ref={:?})", impl_trait_ref); let _: Result<_, ErrorGuaranteed> = try { - compare_self_type(tcx, impl_m, trait_m, impl_trait_ref)?; - compare_number_of_generics(tcx, impl_m, trait_m, false)?; - compare_generic_param_kinds(tcx, impl_m, trait_m, false)?; - compare_number_of_method_arguments(tcx, impl_m, trait_m)?; - compare_synthetic_generics(tcx, impl_m, trait_m)?; - compare_asyncness(tcx, impl_m, trait_m)?; + check_method_is_structurally_compatible(tcx, impl_m, trait_m, impl_trait_ref, false)?; compare_method_predicate_entailment( tcx, impl_m, @@ -60,6 +56,26 @@ pub(super) fn compare_impl_method<'tcx>( }; } +/// Checks a bunch of different properties of the impl/trait methods for +/// compatibility, such as asyncness, number of argument, self receiver kind, +/// and number of early- and late-bound generics. +fn check_method_is_structurally_compatible<'tcx>( + tcx: TyCtxt<'tcx>, + impl_m: ty::AssocItem, + trait_m: ty::AssocItem, + impl_trait_ref: ty::TraitRef<'tcx>, + delay: bool, +) -> Result<(), ErrorGuaranteed> { + compare_self_type(tcx, impl_m, trait_m, impl_trait_ref, delay)?; + compare_number_of_generics(tcx, impl_m, trait_m, delay)?; + compare_generic_param_kinds(tcx, impl_m, trait_m, delay)?; + compare_number_of_method_arguments(tcx, impl_m, trait_m, delay)?; + compare_synthetic_generics(tcx, impl_m, trait_m, delay)?; + compare_asyncness(tcx, impl_m, trait_m, delay)?; + check_region_bounds_on_impl_item(tcx, impl_m, trait_m, delay)?; + Ok(()) +} + /// This function is best explained by example. Consider a trait with it's implementation: /// /// ```rust @@ -176,9 +192,6 @@ fn compare_method_predicate_entailment<'tcx>( let impl_m_predicates = tcx.predicates_of(impl_m.def_id); let trait_m_predicates = tcx.predicates_of(trait_m.def_id); - // Check region bounds. - check_region_bounds_on_impl_item(tcx, impl_m, trait_m, false)?; - // Create obligations for each predicate declared by the impl // definition in the context of the trait's parameter // environment. We can't just use `impl_env.caller_bounds`, @@ -207,7 +220,7 @@ fn compare_method_predicate_entailment<'tcx>( // the new hybrid bounds we computed. let normalize_cause = traits::ObligationCause::misc(impl_m_span, impl_m_def_id); let param_env = ty::ParamEnv::new( - tcx.mk_predicates(&hybrid_preds.predicates), + tcx.mk_clauses(&hybrid_preds.predicates), Reveal::UserFacing, hir::Constness::NotConst, ); @@ -258,7 +271,7 @@ fn compare_method_predicate_entailment<'tcx>( infer::HigherRankedType, tcx.fn_sig(impl_m.def_id).subst_identity(), ); - let unnormalized_impl_fty = tcx.mk_fn_ptr(ty::Binder::dummy(unnormalized_impl_sig)); + let unnormalized_impl_fty = Ty::new_fn_ptr(tcx, ty::Binder::dummy(unnormalized_impl_sig)); let norm_cause = ObligationCause::misc(impl_m_span, impl_m_def_id); let impl_sig = ocx.normalize(&norm_cause, param_env, unnormalized_impl_sig); @@ -275,7 +288,7 @@ fn compare_method_predicate_entailment<'tcx>( // We also have to add the normalized trait signature // as we don't normalize during implied bounds computation. wf_tys.extend(trait_sig.inputs_and_output.iter()); - let trait_fty = tcx.mk_fn_ptr(ty::Binder::dummy(trait_sig)); + let trait_fty = Ty::new_fn_ptr(tcx, ty::Binder::dummy(trait_sig)); debug!("compare_impl_method: trait_fty={:?}", trait_fty); @@ -301,14 +314,16 @@ fn compare_method_predicate_entailment<'tcx>( return Err(emitted); } - if check_implied_wf == CheckImpliedWfMode::Check { + if check_implied_wf == CheckImpliedWfMode::Check && !(impl_sig, trait_sig).references_error() { // We need to check that the impl's args are well-formed given // the hybrid param-env (impl + trait method where-clauses). ocx.register_obligation(traits::Obligation::new( infcx.tcx, ObligationCause::dummy(), param_env, - ty::Binder::dummy(ty::PredicateKind::WellFormed(unnormalized_impl_fty.into())), + ty::Binder::dummy(ty::PredicateKind::Clause(ty::ClauseKind::WellFormed( + unnormalized_impl_fty.into(), + ))), )); } @@ -471,7 +486,8 @@ impl<'tcx> TypeFolder<TyCtxt<'tcx>> for RemapLateBound<'_, 'tcx> { fn fold_region(&mut self, r: ty::Region<'tcx>) -> ty::Region<'tcx> { if let ty::ReFree(fr) = *r { - self.tcx.mk_re_free( + ty::Region::new_free( + self.tcx, fr.scope, self.mapping.get(&fr.bound_region).copied().unwrap_or(fr.bound_region), ) @@ -532,6 +548,7 @@ fn compare_asyncness<'tcx>( tcx: TyCtxt<'tcx>, impl_m: ty::AssocItem, trait_m: ty::AssocItem, + delay: bool, ) -> Result<(), ErrorGuaranteed> { if tcx.asyncness(trait_m.def_id) == hir::IsAsync::Async { match tcx.fn_sig(impl_m.def_id).skip_binder().skip_binder().output().kind() { @@ -542,11 +559,14 @@ fn compare_asyncness<'tcx>( // We don't know if it's ok, but at least it's already an error. } _ => { - return Err(tcx.sess.emit_err(crate::errors::AsyncTraitImplShouldBeAsync { - span: tcx.def_span(impl_m.def_id), - method_name: trait_m.name, - trait_item_span: tcx.hir().span_if_local(trait_m.def_id), - })); + return Err(tcx + .sess + .create_err(crate::errors::AsyncTraitImplShouldBeAsync { + span: tcx.def_span(impl_m.def_id), + method_name: trait_m.name, + trait_item_span: tcx.hir().span_if_local(trait_m.def_id), + }) + .emit_unless(delay)); } }; } @@ -600,9 +620,7 @@ pub(super) fn collect_return_position_impl_trait_in_trait_tys<'tcx>( // First, check a few of the same things as `compare_impl_method`, // just so we don't ICE during substitution later. - compare_number_of_generics(tcx, impl_m, trait_m, true)?; - compare_generic_param_kinds(tcx, impl_m, trait_m, true)?; - check_region_bounds_on_impl_item(tcx, impl_m, trait_m, true)?; + check_method_is_structurally_compatible(tcx, impl_m, trait_m, impl_trait_ref, true)?; let trait_to_impl_substs = impl_trait_ref.substs; @@ -633,11 +651,7 @@ pub(super) fn collect_return_position_impl_trait_in_trait_tys<'tcx>( let impl_sig = ocx.normalize( &norm_cause, param_env, - infcx.instantiate_binder_with_fresh_vars( - return_span, - infer::HigherRankedType, - tcx.fn_sig(impl_m.def_id).subst_identity(), - ), + tcx.liberate_late_bound_regions(impl_m.def_id, tcx.fn_sig(impl_m.def_id).subst_identity()), ); impl_sig.error_reported()?; let impl_return_ty = impl_sig.output(); @@ -647,18 +661,21 @@ pub(super) fn collect_return_position_impl_trait_in_trait_tys<'tcx>( // them with inference variables. // We will use these inference variables to collect the hidden types of RPITITs. let mut collector = ImplTraitInTraitCollector::new(&ocx, return_span, param_env, impl_m_def_id); - let unnormalized_trait_sig = tcx - .liberate_late_bound_regions( - impl_m.def_id, + let unnormalized_trait_sig = infcx + .instantiate_binder_with_fresh_vars( + return_span, + infer::HigherRankedType, tcx.fn_sig(trait_m.def_id).subst(tcx, trait_to_placeholder_substs), ) .fold_with(&mut collector); - debug_assert_ne!( - collector.types.len(), - 0, - "expect >1 RPITITs in call to `collect_return_position_impl_trait_in_trait_tys`" - ); + if !unnormalized_trait_sig.output().references_error() { + debug_assert_ne!( + collector.types.len(), + 0, + "expect >1 RPITITs in call to `collect_return_position_impl_trait_in_trait_tys`" + ); + } let trait_sig = ocx.normalize(&norm_cause, param_env, unnormalized_trait_sig); trait_sig.error_reported()?; @@ -684,7 +701,7 @@ pub(super) fn collect_return_position_impl_trait_in_trait_tys<'tcx>( &cause, hir.get_if_local(impl_m.def_id) .and_then(|node| node.fn_decl()) - .map(|decl| (decl.output.span(), "return type in trait".to_owned())), + .map(|decl| (decl.output.span(), Cow::from("return type in trait"))), Some(infer::ValuePairs::Terms(ExpectedFound { expected: trait_return_ty.into(), found: impl_return_ty.into(), @@ -742,15 +759,17 @@ pub(super) fn collect_return_position_impl_trait_in_trait_tys<'tcx>( let mut collected_tys = FxHashMap::default(); for (def_id, (ty, substs)) in collected_types { - match infcx.fully_resolve(ty) { - Ok(ty) => { + match infcx.fully_resolve((ty, substs)) { + Ok((ty, substs)) => { // `ty` contains free regions that we created earlier while liberating the // trait fn signature. However, projection normalization expects `ty` to // contains `def_id`'s early-bound regions. let id_substs = InternalSubsts::identity_for_item(tcx, def_id); debug!(?id_substs, ?substs); - let map: FxHashMap<ty::GenericArg<'tcx>, ty::GenericArg<'tcx>> = - std::iter::zip(substs, id_substs).collect(); + let map: FxHashMap<_, _> = std::iter::zip(substs, id_substs) + .skip(tcx.generics_of(trait_m.def_id).count()) + .filter_map(|(a, b)| Some((a.as_region()?, b.as_region()?))) + .collect(); debug!(?map); // NOTE(compiler-errors): RPITITs, like all other RPITs, have early-bound @@ -775,33 +794,27 @@ pub(super) fn collect_return_position_impl_trait_in_trait_tys<'tcx>( // same generics. let num_trait_substs = trait_to_impl_substs.len(); let num_impl_substs = tcx.generics_of(impl_m.container_id(tcx)).params.len(); - let ty = tcx.fold_regions(ty, |region, _| { - match region.kind() { - // Remap all free regions, which correspond to late-bound regions in the function. - ty::ReFree(_) => {} - // Remap early-bound regions as long as they don't come from the `impl` itself. - ty::ReEarlyBound(ebr) if tcx.parent(ebr.def_id) != impl_m.container_id(tcx) => {} - _ => return region, - } - let Some(ty::ReEarlyBound(e)) = map.get(®ion.into()).map(|r| r.expect_region().kind()) - else { - return tcx.mk_re_error_with_message(return_span, "expected ReFree to map to ReEarlyBound") - }; - tcx.mk_re_early_bound(ty::EarlyBoundRegion { - def_id: e.def_id, - name: e.name, - index: (e.index as usize - num_trait_substs + num_impl_substs) as u32, - }) - }); - debug!(%ty); - collected_tys.insert(def_id, ty::EarlyBinder(ty)); + let ty = match ty.try_fold_with(&mut RemapHiddenTyRegions { + tcx, + map, + num_trait_substs, + num_impl_substs, + def_id, + impl_def_id: impl_m.container_id(tcx), + ty, + return_span, + }) { + Ok(ty) => ty, + Err(guar) => Ty::new_error(tcx, guar), + }; + collected_tys.insert(def_id, ty::EarlyBinder::bind(ty)); } Err(err) => { let reported = tcx.sess.delay_span_bug( return_span, format!("could not fully resolve: {ty} => {err:?}"), ); - collected_tys.insert(def_id, ty::EarlyBinder(tcx.ty_error(reported))); + collected_tys.insert(def_id, ty::EarlyBinder::bind(Ty::new_error(tcx, reported))); } } } @@ -877,6 +890,97 @@ impl<'tcx> TypeFolder<TyCtxt<'tcx>> for ImplTraitInTraitCollector<'_, 'tcx> { } } +struct RemapHiddenTyRegions<'tcx> { + tcx: TyCtxt<'tcx>, + map: FxHashMap<ty::Region<'tcx>, ty::Region<'tcx>>, + num_trait_substs: usize, + num_impl_substs: usize, + def_id: DefId, + impl_def_id: DefId, + ty: Ty<'tcx>, + return_span: Span, +} + +impl<'tcx> ty::FallibleTypeFolder<TyCtxt<'tcx>> for RemapHiddenTyRegions<'tcx> { + type Error = ErrorGuaranteed; + + fn interner(&self) -> TyCtxt<'tcx> { + self.tcx + } + + fn try_fold_ty(&mut self, t: Ty<'tcx>) -> Result<Ty<'tcx>, Self::Error> { + if let ty::Alias(ty::Opaque, ty::AliasTy { substs, def_id, .. }) = *t.kind() { + let mut mapped_substs = Vec::with_capacity(substs.len()); + for (arg, v) in std::iter::zip(substs, self.tcx.variances_of(def_id)) { + mapped_substs.push(match (arg.unpack(), v) { + // Skip uncaptured opaque substs + (ty::GenericArgKind::Lifetime(_), ty::Bivariant) => arg, + _ => arg.try_fold_with(self)?, + }); + } + Ok(Ty::new_opaque(self.tcx, def_id, self.tcx.mk_substs(&mapped_substs))) + } else { + t.try_super_fold_with(self) + } + } + + fn try_fold_region( + &mut self, + region: ty::Region<'tcx>, + ) -> Result<ty::Region<'tcx>, Self::Error> { + match region.kind() { + // Remap all free regions, which correspond to late-bound regions in the function. + ty::ReFree(_) => {} + // Remap early-bound regions as long as they don't come from the `impl` itself, + // in which case we don't really need to renumber them. + ty::ReEarlyBound(ebr) if self.tcx.parent(ebr.def_id) != self.impl_def_id => {} + _ => return Ok(region), + } + + let e = if let Some(region) = self.map.get(®ion) { + if let ty::ReEarlyBound(e) = region.kind() { e } else { bug!() } + } else { + let guar = match region.kind() { + ty::ReEarlyBound(ty::EarlyBoundRegion { def_id, .. }) + | ty::ReFree(ty::FreeRegion { + bound_region: ty::BoundRegionKind::BrNamed(def_id, _), + .. + }) => { + let return_span = if let ty::Alias(ty::Opaque, opaque_ty) = self.ty.kind() { + self.tcx.def_span(opaque_ty.def_id) + } else { + self.return_span + }; + self.tcx + .sess + .struct_span_err( + return_span, + "return type captures more lifetimes than trait definition", + ) + .span_label(self.tcx.def_span(def_id), "this lifetime was captured") + .span_note( + self.tcx.def_span(self.def_id), + "hidden type must only reference lifetimes captured by this impl trait", + ) + .note(format!("hidden type inferred to be `{}`", self.ty)) + .emit() + } + _ => self.tcx.sess.delay_span_bug(DUMMY_SP, "should've been able to remap region"), + }; + return Err(guar); + }; + + Ok(ty::Region::new_early_bound( + self.tcx, + ty::EarlyBoundRegion { + def_id: e.def_id, + name: e.name, + index: (e.index as usize - self.num_trait_substs + self.num_impl_substs) as u32, + }, + )) + } +} + fn report_trait_method_mismatch<'tcx>( infcx: &InferCtxt<'tcx>, mut cause: ObligationCause<'tcx>, @@ -901,7 +1005,7 @@ fn report_trait_method_mismatch<'tcx>( if trait_m.fn_has_self_parameter => { let ty = trait_sig.inputs()[0]; - let sugg = match ExplicitSelf::determine(ty, |_| ty == impl_trait_ref.self_ty()) { + let sugg = match ExplicitSelf::determine(ty, |ty| ty == impl_trait_ref.self_ty()) { ExplicitSelf::ByValue => "self".to_owned(), ExplicitSelf::ByReference(_, hir::Mutability::Not) => "&self".to_owned(), ExplicitSelf::ByReference(_, hir::Mutability::Mut) => "&mut self".to_owned(), @@ -963,7 +1067,7 @@ fn report_trait_method_mismatch<'tcx>( infcx.err_ctxt().note_type_err( &mut diag, &cause, - trait_err_span.map(|sp| (sp, "type in trait".to_owned())), + trait_err_span.map(|sp| (sp, Cow::from("type in trait"))), Some(infer::ValuePairs::Sigs(ExpectedFound { expected: trait_sig, found: impl_sig })), terr, false, @@ -1095,6 +1199,7 @@ fn compare_self_type<'tcx>( impl_m: ty::AssocItem, trait_m: ty::AssocItem, impl_trait_ref: ty::TraitRef<'tcx>, + delay: bool, ) -> Result<(), ErrorGuaranteed> { // Try to give more informative error messages about self typing // mismatches. Note that any mismatch will also be detected @@ -1143,7 +1248,7 @@ fn compare_self_type<'tcx>( } else { err.note_trait_signature(trait_m.name, trait_m.signature(tcx)); } - return Err(err.emit()); + return Err(err.emit_unless(delay)); } (true, false) => { @@ -1164,7 +1269,7 @@ fn compare_self_type<'tcx>( err.note_trait_signature(trait_m.name, trait_m.signature(tcx)); } - return Err(err.emit()); + return Err(err.emit_unless(delay)); } } @@ -1214,7 +1319,7 @@ fn compare_number_of_generics<'tcx>( // has mismatched type or const generic arguments, then the method that it's // inheriting the generics from will also have mismatched arguments, and // we'll report an error for that instead. Delay a bug for safety, though. - if tcx.opt_rpitit_info(trait_.def_id).is_some() { + if trait_.opt_rpitit_info.is_some() { return Err(tcx.sess.delay_span_bug( rustc_span::DUMMY_SP, "errors comparing numbers of generics of trait/impl functions were not emitted", @@ -1350,6 +1455,7 @@ fn compare_number_of_method_arguments<'tcx>( tcx: TyCtxt<'tcx>, impl_m: ty::AssocItem, trait_m: ty::AssocItem, + delay: bool, ) -> Result<(), ErrorGuaranteed> { let impl_m_fty = tcx.fn_sig(impl_m.def_id); let trait_m_fty = tcx.fn_sig(trait_m.def_id); @@ -1420,7 +1526,7 @@ fn compare_number_of_method_arguments<'tcx>( ), ); - return Err(err.emit()); + return Err(err.emit_unless(delay)); } Ok(()) @@ -1430,6 +1536,7 @@ fn compare_synthetic_generics<'tcx>( tcx: TyCtxt<'tcx>, impl_m: ty::AssocItem, trait_m: ty::AssocItem, + delay: bool, ) -> Result<(), ErrorGuaranteed> { // FIXME(chrisvittal) Clean up this function, list of FIXME items: // 1. Better messages for the span labels @@ -1549,7 +1656,7 @@ fn compare_synthetic_generics<'tcx>( } _ => unreachable!(), } - error_found = Some(err.emit()); + error_found = Some(err.emit_unless(delay)); } } if let Some(reported) = error_found { Err(reported) } else { Ok(()) } @@ -1731,7 +1838,7 @@ pub(super) fn compare_impl_const_raw( infcx.err_ctxt().note_type_err( &mut diag, &cause, - trait_c_span.map(|span| (span, "type in trait".to_owned())), + trait_c_span.map(|span| (span, Cow::from("type in trait"))), Some(infer::ValuePairs::Terms(ExpectedFound { expected: trait_ty.into(), found: impl_ty.into(), @@ -1814,7 +1921,7 @@ fn compare_type_predicate_entailment<'tcx>( let impl_ty_span = tcx.def_span(impl_ty_def_id); let normalize_cause = traits::ObligationCause::misc(impl_ty_span, impl_ty_def_id); let param_env = ty::ParamEnv::new( - tcx.mk_predicates(&hybrid_preds.predicates), + tcx.mk_clauses(&hybrid_preds.predicates), Reveal::UserFacing, hir::Constness::NotConst, ); @@ -1922,7 +2029,8 @@ pub(super) fn check_type_bounds<'tcx>( let kind = ty::BoundTyKind::Param(param.def_id, param.name); let bound_var = ty::BoundVariableKind::Ty(kind); bound_vars.push(bound_var); - tcx.mk_bound( + Ty::new_bound( + tcx, ty::INNERMOST, ty::BoundTy { var: ty::BoundVar::from_usize(bound_vars.len() - 1), kind }, ) @@ -1932,7 +2040,8 @@ pub(super) fn check_type_bounds<'tcx>( let kind = ty::BoundRegionKind::BrNamed(param.def_id, param.name); let bound_var = ty::BoundVariableKind::Region(kind); bound_vars.push(bound_var); - tcx.mk_re_late_bound( + ty::Region::new_late_bound( + tcx, ty::INNERMOST, ty::BoundRegion { var: ty::BoundVar::from_usize(bound_vars.len() - 1), kind }, ) @@ -1941,11 +2050,10 @@ pub(super) fn check_type_bounds<'tcx>( GenericParamDefKind::Const { .. } => { let bound_var = ty::BoundVariableKind::Const; bound_vars.push(bound_var); - tcx.mk_const( - ty::ConstKind::Bound( - ty::INNERMOST, - ty::BoundVar::from_usize(bound_vars.len() - 1), - ), + ty::Const::new_bound( + tcx, + ty::INNERMOST, + ty::BoundVar::from_usize(bound_vars.len() - 1), tcx.type_of(param.def_id) .no_bound_vars() .expect("const parameter types cannot be generic"), @@ -1989,7 +2097,7 @@ pub(super) fn check_type_bounds<'tcx>( .to_predicate(tcx), ), }; - ty::ParamEnv::new(tcx.mk_predicates(&predicates), Reveal::UserFacing, param_env.constness()) + ty::ParamEnv::new(tcx.mk_clauses(&predicates), Reveal::UserFacing, param_env.constness()) }; debug!(?normalize_param_env); @@ -2003,7 +2111,7 @@ pub(super) fn check_type_bounds<'tcx>( // A synthetic impl Trait for RPITIT desugaring has no HIR, which we currently use to get the // span for an impl's associated type. Instead, for these, use the def_span for the synthesized // associated type. - let impl_ty_span = if tcx.opt_rpitit_info(impl_ty.def_id).is_some() { + let impl_ty_span = if impl_ty.opt_rpitit_info.is_some() { tcx.def_span(impl_ty_def_id) } else { match tcx.hir().get_by_def_id(impl_ty_def_id) { @@ -2015,7 +2123,7 @@ pub(super) fn check_type_bounds<'tcx>( _ => bug!(), } }; - let assumed_wf_types = ocx.assumed_wf_types(param_env, impl_ty_span, impl_ty_def_id); + let assumed_wf_types = ocx.assumed_wf_types_and_report_errors(param_env, impl_ty_def_id)?; let normalize_cause = ObligationCause::new( impl_ty_span, |