diff --git a/compiler/rustc_ty_utils/src/opaque_types.rs b/compiler/rustc_ty_utils/src/opaque_types.rs index 86c7551882aab..282595169737d 100644 --- a/compiler/rustc_ty_utils/src/opaque_types.rs +++ b/compiler/rustc_ty_utils/src/opaque_types.rs @@ -22,11 +22,20 @@ struct OpaqueTypeCollector<'tcx> { seen: FxHashSet, span: Option, + + mode: CollectionMode, +} + +enum CollectionMode { + /// For impl trait in assoc types we only permit collecting them from + /// associated types of the same impl block. + ImplTraitInAssocTypes, + TypeAliasImplTraitTransition, } impl<'tcx> OpaqueTypeCollector<'tcx> { - fn new(tcx: TyCtxt<'tcx>, item: LocalDefId) -> Self { - Self { tcx, opaques: Vec::new(), item, seen: Default::default(), span: None } + fn new(tcx: TyCtxt<'tcx>, item: LocalDefId, mode: CollectionMode) -> Self { + Self { tcx, opaques: Vec::new(), item, seen: Default::default(), span: None, mode } } fn span(&self) -> Span { @@ -251,6 +260,9 @@ impl<'tcx> TypeVisitor> for OpaqueTypeCollector<'tcx> { } } ty::Adt(def, _) if def.did().is_local() => { + if let CollectionMode::ImplTraitInAssocTypes = self.mode { + return ControlFlow::Continue(()); + } if !self.seen.insert(def.did().expect_local()) { return ControlFlow::Continue(()); } @@ -275,89 +287,13 @@ impl<'tcx> TypeVisitor> for OpaqueTypeCollector<'tcx> { } } -struct ImplTraitInAssocTypeCollector<'tcx>(OpaqueTypeCollector<'tcx>); - -impl<'tcx> super::sig_types::SpannedTypeVisitor<'tcx> for ImplTraitInAssocTypeCollector<'tcx> { - #[instrument(skip(self), ret, level = "trace")] - fn visit(&mut self, span: Span, value: impl TypeVisitable>) -> ControlFlow { - let old = self.0.span; - self.0.span = Some(span); - value.visit_with(self); - self.0.span = old; - - ControlFlow::Continue(()) - } -} - -impl<'tcx> TypeVisitor> for ImplTraitInAssocTypeCollector<'tcx> { - #[instrument(skip(self), ret, level = "trace")] - fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow { - t.super_visit_with(self)?; - match t.kind() { - ty::Alias(ty::Opaque, alias_ty) if alias_ty.def_id.is_local() => { - self.0.visit_opaque_ty(alias_ty); - } - ty::Alias(ty::Projection, alias_ty) => { - // This avoids having to do normalization of `Self::AssocTy` by only - // supporting the case of a method defining opaque types from assoc types - // in the same impl block. - let parent_trait_ref = self - .0 - .parent_trait_ref() - .expect("impl trait in assoc type collector used on non-assoc item"); - // If the trait ref of the associated item and the impl differs, - // then we can't use the impl's identity args below, so - // just skip. - if alias_ty.trait_ref(self.0.tcx) == parent_trait_ref { - let parent = self.0.parent().expect("we should have a parent here"); - - for &assoc in self.0.tcx.associated_items(parent).in_definition_order() { - trace!(?assoc); - if assoc.trait_item_def_id != Some(alias_ty.def_id) { - continue; - } - - // If the type is further specializable, then the type_of - // is not actually correct below. - if !assoc.defaultness(self.0.tcx).is_final() { - continue; - } - - let impl_args = alias_ty.args.rebase_onto( - self.0.tcx, - parent_trait_ref.def_id, - ty::GenericArgs::identity_for_item(self.0.tcx, parent), - ); - - if check_args_compatible(self.0.tcx, assoc, impl_args) { - return self - .0 - .tcx - .type_of(assoc.def_id) - .instantiate(self.0.tcx, impl_args) - .visit_with(self); - } else { - self.0.tcx.dcx().span_bug( - self.0.tcx.def_span(assoc.def_id), - "item had incorrect args", - ); - } - } - } - } - _ => trace!(kind=?t.kind()), - } - ControlFlow::Continue(()) - } -} - fn impl_trait_in_assoc_types_defined_by<'tcx>( tcx: TyCtxt<'tcx>, item: LocalDefId, ) -> &'tcx ty::List { - let mut collector = ImplTraitInAssocTypeCollector(OpaqueTypeCollector::new(tcx, item)); + let mut collector = OpaqueTypeCollector::new(tcx, item, CollectionMode::ImplTraitInAssocTypes); super::sig_types::walk_types(tcx, item, &mut collector); - tcx.mk_local_def_ids(&collector.0.opaques) + tcx.mk_local_def_ids(&collector.opaques) } fn opaque_types_defined_by<'tcx>( @@ -366,7 +302,8 @@ fn opaque_types_defined_by<'tcx>( ) -> &'tcx ty::List { let kind = tcx.def_kind(item); trace!(?kind); - let mut collector = OpaqueTypeCollector::new(tcx, item); + let mut collector = + OpaqueTypeCollector::new(tcx, item, CollectionMode::TypeAliasImplTraitTransition); super::sig_types::walk_types(tcx, item, &mut collector); match kind { DefKind::AssocFn diff --git a/tests/ui/type-alias-impl-trait/hidden_behind_struct_field3.rs b/tests/ui/type-alias-impl-trait/hidden_behind_struct_field3.rs new file mode 100644 index 0000000000000..1278563a92c46 --- /dev/null +++ b/tests/ui/type-alias-impl-trait/hidden_behind_struct_field3.rs @@ -0,0 +1,28 @@ +//! This test demonstrates a bug where we accidentally +//! detected opaque types in struct fields, but only if nested +//! in projections of another opaque type. + +#![feature(impl_trait_in_assoc_type)] + +struct Bar; + +trait Trait: Sized { + type Assoc2; + type Assoc; + fn foo() -> Self::Assoc; +} + +impl Trait for Bar { + type Assoc2 = impl std::fmt::Debug; + type Assoc = impl Iterator; + fn foo() -> Self::Assoc { + vec![Foo { field: () }].into_iter() + //~^ ERROR item constrains opaque type that is not in its signature + } +} + +struct Foo { + field: ::Assoc2, +} + +fn main() {} diff --git a/tests/ui/type-alias-impl-trait/hidden_behind_struct_field3.stderr b/tests/ui/type-alias-impl-trait/hidden_behind_struct_field3.stderr new file mode 100644 index 0000000000000..0570e0303c633 --- /dev/null +++ b/tests/ui/type-alias-impl-trait/hidden_behind_struct_field3.stderr @@ -0,0 +1,15 @@ +error: item constrains opaque type that is not in its signature + --> $DIR/hidden_behind_struct_field3.rs:19:27 + | +LL | vec![Foo { field: () }].into_iter() + | ^^ + | + = note: this item must mention the opaque type in its signature in order to be able to register hidden types +note: this item must mention the opaque type in its signature in order to be able to register hidden types + --> $DIR/hidden_behind_struct_field3.rs:18:8 + | +LL | fn foo() -> Self::Assoc { + | ^^^ + +error: aborting due to 1 previous error +