diff options
Diffstat (limited to 'compiler/rustc_hir_analysis/src/coherence')
6 files changed, 273 insertions, 145 deletions
diff --git a/compiler/rustc_hir_analysis/src/coherence/builtin.rs b/compiler/rustc_hir_analysis/src/coherence/builtin.rs index 28c040878..ffb68abf9 100644 --- a/compiler/rustc_hir_analysis/src/coherence/builtin.rs +++ b/compiler/rustc_hir_analysis/src/coherence/builtin.rs @@ -11,7 +11,7 @@ use rustc_infer::infer::outlives::env::OutlivesEnvironment; use rustc_infer::infer::TyCtxtInferExt; use rustc_infer::infer::{self, RegionResolutionError}; use rustc_middle::ty::adjustment::CoerceUnsizedInfo; -use rustc_middle::ty::{self, suggest_constraining_type_params, Ty, TyCtxt, TypeVisitable}; +use rustc_middle::ty::{self, suggest_constraining_type_params, Ty, TyCtxt, TypeVisitableExt}; use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt; use rustc_trait_selection::traits::misc::{ type_allowed_to_implement_copy, CopyImplementationError, InfringingFieldsReason, @@ -50,13 +50,13 @@ impl<'tcx> Checker<'tcx> { fn visit_implementation_of_drop(tcx: TyCtxt<'_>, impl_did: LocalDefId) { // Destructors only work on local ADT types. - match tcx.type_of(impl_did).kind() { + match tcx.type_of(impl_did).subst_identity().kind() { ty::Adt(def, _) if def.did().is_local() => return, ty::Error(_) => return, _ => {} } - let ItemKind::Impl(impl_) = tcx.hir().expect_item(impl_did).kind else { bug!("expected Drop impl item") }; + let impl_ = tcx.hir().expect_item(impl_did).expect_impl(); tcx.sess.emit_err(DropImplOnWrongItem { span: impl_.self_ty.span }); } @@ -64,9 +64,7 @@ fn visit_implementation_of_drop(tcx: TyCtxt<'_>, impl_did: LocalDefId) { fn visit_implementation_of_copy(tcx: TyCtxt<'_>, impl_did: LocalDefId) { debug!("visit_implementation_of_copy: impl_did={:?}", impl_did); - let impl_hir_id = tcx.hir().local_def_id_to_hir_id(impl_did); - - let self_type = tcx.type_of(impl_did); + let self_type = tcx.type_of(impl_did).subst_identity(); debug!("visit_implementation_of_copy: self_type={:?} (bound)", self_type); let param_env = tcx.param_env(impl_did); @@ -80,7 +78,7 @@ fn visit_implementation_of_copy(tcx: TyCtxt<'_>, impl_did: LocalDefId) { _ => bug!("expected Copy impl item"), }; - let cause = traits::ObligationCause::misc(span, impl_hir_id); + let cause = traits::ObligationCause::misc(span, impl_did); match type_allowed_to_implement_copy(tcx, param_env, self_type, cause) { Ok(()) => {} Err(CopyImplementationError::InfrigingFields(fields)) => { @@ -178,6 +176,7 @@ fn visit_implementation_of_copy(tcx: TyCtxt<'_>, impl_did: LocalDefId) { bounds.iter().map(|(param, constraint, def_id)| { (param.as_str(), constraint.as_str(), *def_id) }), + None, ); err.emit(); } @@ -203,12 +202,11 @@ fn visit_implementation_of_coerce_unsized(tcx: TyCtxt<'_>, impl_did: LocalDefId) fn visit_implementation_of_dispatch_from_dyn(tcx: TyCtxt<'_>, impl_did: LocalDefId) { debug!("visit_implementation_of_dispatch_from_dyn: impl_did={:?}", impl_did); - let impl_hir_id = tcx.hir().local_def_id_to_hir_id(impl_did); - let span = tcx.hir().span(impl_hir_id); + let span = tcx.def_span(impl_did); let dispatch_from_dyn_trait = tcx.require_lang_item(LangItem::DispatchFromDyn, Some(span)); - let source = tcx.type_of(impl_did); + let source = tcx.type_of(impl_did).subst_identity(); assert!(!source.has_escaping_bound_vars()); let target = { let trait_ref = tcx.impl_trait_ref(impl_did).unwrap().subst_identity(); @@ -224,7 +222,7 @@ fn visit_implementation_of_dispatch_from_dyn(tcx: TyCtxt<'_>, impl_did: LocalDef let create_err = |msg: &str| struct_span_err!(tcx.sess, span, E0378, "{}", msg); let infcx = tcx.infer_ctxt().build(); - let cause = ObligationCause::misc(span, impl_hir_id); + let cause = ObligationCause::misc(span, impl_did); use rustc_type_ir::sty::TyKind::*; match (source.kind(), target.kind()) { @@ -372,7 +370,7 @@ pub fn coerce_unsized_info<'tcx>(tcx: TyCtxt<'tcx>, impl_did: DefId) -> CoerceUn tcx.sess.fatal(&format!("`CoerceUnsized` implementation {}", err.to_string())); }); - let source = tcx.type_of(impl_did); + let source = tcx.type_of(impl_did).subst_identity(); let trait_ref = tcx.impl_trait_ref(impl_did).unwrap().subst_identity(); assert_eq!(trait_ref.def_id, coerce_unsized_trait); let target = trait_ref.substs.type_at(1); @@ -386,8 +384,7 @@ pub fn coerce_unsized_info<'tcx>(tcx: TyCtxt<'tcx>, impl_did: DefId) -> CoerceUn debug!("visit_implementation_of_coerce_unsized: {:?} -> {:?} (free)", source, target); let infcx = tcx.infer_ctxt().build(); - let impl_hir_id = tcx.hir().local_def_id_to_hir_id(impl_did); - let cause = ObligationCause::misc(span, impl_hir_id); + let cause = ObligationCause::misc(span, impl_did); let check_mutbl = |mt_a: ty::TypeAndMut<'tcx>, mt_b: ty::TypeAndMut<'tcx>, mk_ptr: &dyn Fn(Ty<'tcx>) -> Ty<'tcx>| { @@ -440,7 +437,7 @@ pub fn coerce_unsized_info<'tcx>(tcx: TyCtxt<'tcx>, impl_did: DefId) -> CoerceUn } // Here we are considering a case of converting - // `S<P0...Pn>` to S<Q0...Qn>`. As an example, let's imagine a struct `Foo<T, U>`, + // `S<P0...Pn>` to `S<Q0...Qn>`. As an example, let's imagine a struct `Foo<T, U>`, // which acts like a pointer to `U`, but carries along some extra data of type `T`: // // struct Foo<T, U> { @@ -485,7 +482,7 @@ pub fn coerce_unsized_info<'tcx>(tcx: TyCtxt<'tcx>, impl_did: DefId) -> CoerceUn .filter_map(|(i, f)| { let (a, b) = (f.ty(tcx, substs_a), f.ty(tcx, substs_b)); - if tcx.type_of(f.did).is_phantom_data() { + if tcx.type_of(f.did).subst_identity().is_phantom_data() { // Ignore PhantomData fields return None; } @@ -575,7 +572,7 @@ pub fn coerce_unsized_info<'tcx>(tcx: TyCtxt<'tcx>, impl_did: DefId) -> CoerceUn }; // Register an obligation for `A: Trait<B>`. - let cause = traits::ObligationCause::misc(span, impl_hir_id); + let cause = traits::ObligationCause::misc(span, impl_did); let predicate = predicate_for_trait_def(tcx, param_env, cause, trait_def_id, 0, [source, target]); let errors = traits::fully_solve_obligation(&infcx, predicate); diff --git a/compiler/rustc_hir_analysis/src/coherence/inherent_impls.rs b/compiler/rustc_hir_analysis/src/coherence/inherent_impls.rs index dfb982409..02f3eeee0 100644 --- a/compiler/rustc_hir_analysis/src/coherence/inherent_impls.rs +++ b/compiler/rustc_hir_analysis/src/coherence/inherent_impls.rs @@ -14,7 +14,6 @@ use rustc_hir::def_id::{CrateNum, DefId, LocalDefId}; use rustc_middle::ty::fast_reject::{simplify_type, SimplifiedType, TreatParams}; use rustc_middle::ty::{self, CrateInherentImpls, Ty, TyCtxt}; use rustc_span::symbol::sym; -use rustc_span::Span; /// On-demand query: yields a map containing all types mapped to their inherent impls. pub fn crate_inherent_impls(tcx: TyCtxt<'_>, (): ()) -> CrateInherentImpls { @@ -57,86 +56,76 @@ const ADD_ATTR: &str = "alternatively add `#[rustc_allow_incoherent_impl]` to the relevant impl items"; impl<'tcx> InherentCollect<'tcx> { - fn check_def_id(&mut self, item: &hir::Item<'_>, self_ty: Ty<'tcx>, def_id: DefId) { - let impl_def_id = item.owner_id; - if let Some(def_id) = def_id.as_local() { + fn check_def_id(&mut self, impl_def_id: LocalDefId, self_ty: Ty<'tcx>, ty_def_id: DefId) { + if let Some(ty_def_id) = ty_def_id.as_local() { // Add the implementation to the mapping from implementation to base // type def ID, if there is a base type for this implementation and // the implementation does not have any associated traits. - let vec = self.impls_map.inherent_impls.entry(def_id).or_default(); + let vec = self.impls_map.inherent_impls.entry(ty_def_id).or_default(); vec.push(impl_def_id.to_def_id()); return; } if self.tcx.features().rustc_attrs { - let hir::ItemKind::Impl(&hir::Impl { items, .. }) = item.kind else { - bug!("expected `impl` item: {:?}", item); - }; + let items = self.tcx.associated_item_def_ids(impl_def_id); - if !self.tcx.has_attr(def_id, sym::rustc_has_incoherent_inherent_impls) { + if !self.tcx.has_attr(ty_def_id, sym::rustc_has_incoherent_inherent_impls) { + let impl_span = self.tcx.def_span(impl_def_id); struct_span_err!( self.tcx.sess, - item.span, + impl_span, E0390, "cannot define inherent `impl` for a type outside of the crate where the type is defined", ) .help(INTO_DEFINING_CRATE) - .span_help(item.span, ADD_ATTR_TO_TY) + .span_help(impl_span, ADD_ATTR_TO_TY) .emit(); return; } - for impl_item in items { - if !self - .tcx - .has_attr(impl_item.id.owner_id.to_def_id(), sym::rustc_allow_incoherent_impl) - { + for &impl_item in items { + if !self.tcx.has_attr(impl_item, sym::rustc_allow_incoherent_impl) { + let impl_span = self.tcx.def_span(impl_def_id); struct_span_err!( self.tcx.sess, - item.span, + impl_span, E0390, "cannot define inherent `impl` for a type outside of the crate where the type is defined", ) .help(INTO_DEFINING_CRATE) - .span_help(impl_item.span, ADD_ATTR) + .span_help(self.tcx.def_span(impl_item), ADD_ATTR) .emit(); return; } } if let Some(simp) = simplify_type(self.tcx, self_ty, TreatParams::AsInfer) { - self.impls_map.incoherent_impls.entry(simp).or_default().push(impl_def_id.def_id); + self.impls_map.incoherent_impls.entry(simp).or_default().push(impl_def_id); } else { bug!("unexpected self type: {:?}", self_ty); } } else { + let impl_span = self.tcx.def_span(impl_def_id); struct_span_err!( self.tcx.sess, - item.span, + impl_span, E0116, "cannot define inherent `impl` for a type outside of the crate \ where the type is defined" ) - .span_label(item.span, "impl for type defined outside of crate.") + .span_label(impl_span, "impl for type defined outside of crate.") .note("define and implement a trait or new type instead") .emit(); } } - fn check_primitive_impl( - &mut self, - impl_def_id: LocalDefId, - ty: Ty<'tcx>, - items: &[hir::ImplItemRef], - span: Span, - ) { + fn check_primitive_impl(&mut self, impl_def_id: LocalDefId, ty: Ty<'tcx>) { + let items = self.tcx.associated_item_def_ids(impl_def_id); if !self.tcx.hir().rustc_coherence_is_core() { if self.tcx.features().rustc_attrs { - for item in items { - if !self - .tcx - .has_attr(item.id.owner_id.to_def_id(), sym::rustc_allow_incoherent_impl) - { + for &impl_item in items { + if !self.tcx.has_attr(impl_item, sym::rustc_allow_incoherent_impl) { + let span = self.tcx.def_span(impl_def_id); struct_span_err!( self.tcx.sess, span, @@ -144,12 +133,13 @@ impl<'tcx> InherentCollect<'tcx> { "cannot define inherent `impl` for primitive types outside of `core`", ) .help(INTO_CORE) - .span_help(item.span, ADD_ATTR) + .span_help(self.tcx.def_span(impl_item), ADD_ATTR) .emit(); return; } } } else { + let span = self.tcx.def_span(impl_def_id); let mut err = struct_span_err!( self.tcx.sess, span, @@ -177,34 +167,27 @@ impl<'tcx> InherentCollect<'tcx> { } fn check_item(&mut self, id: hir::ItemId) { - if !matches!(self.tcx.def_kind(id.owner_id), DefKind::Impl) { + if !matches!(self.tcx.def_kind(id.owner_id), DefKind::Impl { of_trait: false }) { return; } - let item = self.tcx.hir().item(id); - let hir::ItemKind::Impl(hir::Impl { of_trait: None, self_ty: ty, items, .. }) = item.kind else { - return; - }; - - let self_ty = self.tcx.type_of(item.owner_id); + let id = id.owner_id.def_id; + let item_span = self.tcx.def_span(id); + let self_ty = self.tcx.type_of(id).subst_identity(); match *self_ty.kind() { - ty::Adt(def, _) => { - self.check_def_id(item, self_ty, def.did()); - } - ty::Foreign(did) => { - self.check_def_id(item, self_ty, did); - } + ty::Adt(def, _) => self.check_def_id(id, self_ty, def.did()), + ty::Foreign(did) => self.check_def_id(id, self_ty, did), ty::Dynamic(data, ..) if data.principal_def_id().is_some() => { - self.check_def_id(item, self_ty, data.principal_def_id().unwrap()); + self.check_def_id(id, self_ty, data.principal_def_id().unwrap()); } ty::Dynamic(..) => { struct_span_err!( self.tcx.sess, - ty.span, + item_span, E0785, "cannot define inherent `impl` for a dyn auto trait" ) - .span_label(ty.span, "impl requires at least one non-auto trait") + .span_label(item_span, "impl requires at least one non-auto trait") .note("define and implement a new trait or type instead") .emit(); } @@ -220,18 +203,16 @@ impl<'tcx> InherentCollect<'tcx> { | ty::Ref(..) | ty::Never | ty::FnPtr(_) - | ty::Tuple(..) => { - self.check_primitive_impl(item.owner_id.def_id, self_ty, items, ty.span) - } + | ty::Tuple(..) => self.check_primitive_impl(id, self_ty), ty::Alias(..) | ty::Param(_) => { let mut err = struct_span_err!( self.tcx.sess, - ty.span, + item_span, E0118, "no nominal type found for inherent implementation" ); - err.span_label(ty.span, "impl requires a nominal type") + err.span_label(item_span, "impl requires a nominal type") .note("either implement a trait on it or create a newtype to wrap it instead"); err.emit(); @@ -240,10 +221,11 @@ impl<'tcx> InherentCollect<'tcx> { | ty::Closure(..) | ty::Generator(..) | ty::GeneratorWitness(..) + | ty::GeneratorWitnessMIR(..) | ty::Bound(..) | ty::Placeholder(_) | ty::Infer(_) => { - bug!("unexpected impl self type of impl: {:?} {:?}", item.owner_id, self_ty); + bug!("unexpected impl self type of impl: {:?} {:?}", id, self_ty); } ty::Error(_) => {} } diff --git a/compiler/rustc_hir_analysis/src/coherence/inherent_impls_overlap.rs b/compiler/rustc_hir_analysis/src/coherence/inherent_impls_overlap.rs index a9331af4e..7bca4edcc 100644 --- a/compiler/rustc_hir_analysis/src/coherence/inherent_impls_overlap.rs +++ b/compiler/rustc_hir_analysis/src/coherence/inherent_impls_overlap.rs @@ -27,8 +27,8 @@ impl<'tcx> InherentOverlapChecker<'tcx> { /// namespace. fn impls_have_common_items( &self, - impl_items1: &ty::AssocItems<'_>, - impl_items2: &ty::AssocItems<'_>, + impl_items1: &ty::AssocItems, + impl_items2: &ty::AssocItems, ) -> bool { let mut impl_items1 = &impl_items1; let mut impl_items2 = &impl_items2; @@ -38,10 +38,10 @@ impl<'tcx> InherentOverlapChecker<'tcx> { std::mem::swap(&mut impl_items1, &mut impl_items2); } - for item1 in impl_items1.in_definition_order() { + for &item1 in impl_items1.in_definition_order() { let collision = impl_items2 .filter_by_name_unhygienic(item1.name) - .any(|item2| self.compare_hygienically(item1, item2)); + .any(|&item2| self.compare_hygienically(item1, item2)); if collision { return true; @@ -51,7 +51,7 @@ impl<'tcx> InherentOverlapChecker<'tcx> { false } - fn compare_hygienically(&self, item1: &ty::AssocItem, item2: &ty::AssocItem) -> bool { + fn compare_hygienically(&self, item1: ty::AssocItem, item2: ty::AssocItem) -> bool { // Symbols and namespace match, compare hygienically. item1.kind.namespace() == item2.kind.namespace() && item1.ident(self.tcx).normalize_to_macros_2_0() @@ -98,10 +98,10 @@ impl<'tcx> InherentOverlapChecker<'tcx> { let impl_items1 = self.tcx.associated_items(impl1); let impl_items2 = self.tcx.associated_items(impl2); - for item1 in impl_items1.in_definition_order() { + for &item1 in impl_items1.in_definition_order() { let collision = impl_items2 .filter_by_name_unhygienic(item1.name) - .find(|item2| self.compare_hygienically(item1, item2)); + .find(|&&item2| self.compare_hygienically(item1, item2)); if let Some(item2) = collision { let name = item1.ident(self.tcx).normalize_to_macros_2_0(); diff --git a/compiler/rustc_hir_analysis/src/coherence/mod.rs b/compiler/rustc_hir_analysis/src/coherence/mod.rs index d3b5778ba..23490bc09 100644 --- a/compiler/rustc_hir_analysis/src/coherence/mod.rs +++ b/compiler/rustc_hir_analysis/src/coherence/mod.rs @@ -8,7 +8,7 @@ use rustc_errors::{error_code, struct_span_err}; use rustc_hir::def_id::{DefId, LocalDefId}; use rustc_middle::ty::query::Providers; -use rustc_middle::ty::{self, TyCtxt, TypeVisitable}; +use rustc_middle::ty::{self, TyCtxt, TypeVisitableExt}; use rustc_span::sym; use rustc_trait_selection::traits; @@ -169,7 +169,7 @@ fn check_object_overlap<'tcx>( }); for component_def_id in component_def_ids { - if !tcx.is_object_safe(component_def_id) { + if !tcx.check_is_object_safe(component_def_id) { // Without the 'object_safe_for_dispatch' feature this is an error // which will be reported by wfcheck. Ignore it here. // This is tested by `coherence-impl-trait-for-trait-object-safe.rs`. diff --git a/compiler/rustc_hir_analysis/src/coherence/orphan.rs b/compiler/rustc_hir_analysis/src/coherence/orphan.rs index 95b03eb82..1f2de3f21 100644 --- a/compiler/rustc_hir_analysis/src/coherence/orphan.rs +++ b/compiler/rustc_hir_analysis/src/coherence/orphan.rs @@ -8,7 +8,8 @@ use rustc_hir as hir; use rustc_middle::ty::subst::InternalSubsts; use rustc_middle::ty::util::IgnoreRegions; use rustc_middle::ty::{ - self, ImplPolarity, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitor, + self, AliasKind, ImplPolarity, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitableExt, + TypeVisitor, }; use rustc_session::lint; use rustc_span::def_id::{DefId, LocalDefId}; @@ -39,25 +40,27 @@ fn do_orphan_check_impl<'tcx>( ) -> Result<(), ErrorGuaranteed> { let trait_def_id = trait_ref.def_id; - let item = tcx.hir().expect_item(def_id); - let hir::ItemKind::Impl(impl_) = item.kind else { - bug!("{:?} is not an impl: {:?}", def_id, item); - }; - let sp = tcx.def_span(def_id); - let tr = impl_.of_trait.as_ref().unwrap(); - - match traits::orphan_check(tcx, item.owner_id.to_def_id()) { + match traits::orphan_check(tcx, def_id.to_def_id()) { Ok(()) => {} - Err(err) => emit_orphan_check_error( - tcx, - sp, - item.span, - tr.path.span, - trait_ref, - impl_.self_ty.span, - &impl_.generics, - err, - )?, + Err(err) => { + let item = tcx.hir().expect_item(def_id); + let hir::ItemKind::Impl(impl_) = item.kind else { + bug!("{:?} is not an impl: {:?}", def_id, item); + }; + let tr = impl_.of_trait.as_ref().unwrap(); + let sp = tcx.def_span(def_id); + + emit_orphan_check_error( + tcx, + sp, + item.span, + tr.path.span, + trait_ref, + impl_.self_ty.span, + &impl_.generics, + err, + )? + } } // In addition to the above rules, we restrict impls of auto traits @@ -86,7 +89,7 @@ fn do_orphan_check_impl<'tcx>( // struct B { } // impl Foo for A { } // impl Foo for B { } - // impl !Send for (A, B) { } + // impl !Foo for (A, B) { } // ``` // // This final impl is legal according to the orphan @@ -99,50 +102,198 @@ fn do_orphan_check_impl<'tcx>( tcx.trait_is_auto(trait_def_id) ); - if tcx.trait_is_auto(trait_def_id) && !trait_def_id.is_local() { + if tcx.trait_is_auto(trait_def_id) { let self_ty = trait_ref.self_ty(); - let opt_self_def_id = match *self_ty.kind() { - ty::Adt(self_def, _) => Some(self_def.did()), - ty::Foreign(did) => Some(did), - _ => None, - }; - let msg = match opt_self_def_id { - // We only want to permit nominal types, but not *all* nominal types. - // They must be local to the current crate, so that people - // can't do `unsafe impl Send for Rc<SomethingLocal>` or - // `impl !Send for Box<SomethingLocalAndSend>`. - Some(self_def_id) => { - if self_def_id.is_local() { - None + // If the impl is in the same crate as the auto-trait, almost anything + // goes. + // + // impl MyAuto for Rc<Something> {} // okay + // impl<T> !MyAuto for *const T {} // okay + // impl<T> MyAuto for T {} // okay + // + // But there is one important exception: implementing for a trait object + // is not allowed. + // + // impl MyAuto for dyn Trait {} // NOT OKAY + // impl<T: ?Sized> MyAuto for T {} // NOT OKAY + // + // With this restriction, it's guaranteed that an auto-trait is + // implemented for a trait object if and only if the auto-trait is one + // of the trait object's trait bounds (or a supertrait of a bound). In + // other words `dyn Trait + AutoTrait` always implements AutoTrait, + // while `dyn Trait` never implements AutoTrait. + // + // This is necessary in order for autotrait bounds on methods of trait + // objects to be sound. + // + // auto trait AutoTrait {} + // + // trait ObjectSafeTrait { + // fn f(&self) where Self: AutoTrait; + // } + // + // We can allow f to be called on `dyn ObjectSafeTrait + AutoTrait`. + // + // If we didn't deny `impl AutoTrait for dyn Trait`, it would be unsound + // for the ObjectSafeTrait shown above to be object safe because someone + // could take some type implementing ObjectSafeTrait but not AutoTrait, + // unsize it to `dyn ObjectSafeTrait`, and call .f() which has no + // concrete implementation (issue #50781). + enum LocalImpl { + Allow, + Disallow { problematic_kind: &'static str }, + } + + // If the auto-trait is from a dependency, it must only be getting + // implemented for a nominal type, and specifically one local to the + // current crate. + // + // impl<T> Sync for MyStruct<T> {} // okay + // + // impl Sync for Rc<MyStruct> {} // NOT OKAY + enum NonlocalImpl { + Allow, + DisallowBecauseNonlocal, + DisallowOther, + } + + // Exhaustive match considering that this logic is essential for + // soundness. + let (local_impl, nonlocal_impl) = match self_ty.kind() { + // struct Struct<T>; + // impl AutoTrait for Struct<Foo> {} + ty::Adt(self_def, _) => ( + LocalImpl::Allow, + if self_def.did().is_local() { + NonlocalImpl::Allow } else { - Some(( - format!( - "cross-crate traits with a default impl, like `{}`, \ - can only be implemented for a struct/enum type \ - defined in the current crate", - tcx.def_path_str(trait_def_id) - ), - "can't implement cross-crate trait for type in another crate", - )) - } + NonlocalImpl::DisallowBecauseNonlocal + }, + ), + + // extern { type OpaqueType; } + // impl AutoTrait for OpaqueType {} + ty::Foreign(did) => ( + LocalImpl::Allow, + if did.is_local() { + NonlocalImpl::Allow + } else { + NonlocalImpl::DisallowBecauseNonlocal + }, + ), + + // impl AutoTrait for dyn Trait {} + ty::Dynamic(..) => ( + LocalImpl::Disallow { problematic_kind: "trait object" }, + NonlocalImpl::DisallowOther, + ), + + // impl<T> AutoTrait for T {} + // impl<T: ?Sized> AutoTrait for T {} + ty::Param(..) => ( + if self_ty.is_sized(tcx, tcx.param_env(def_id)) { + LocalImpl::Allow + } else { + LocalImpl::Disallow { problematic_kind: "generic type" } + }, + NonlocalImpl::DisallowOther, + ), + + // trait Id { type This: ?Sized; } + // impl<T: ?Sized> Id for T { + // type This = T; + // } + // impl<T: ?Sized> AutoTrait for <T as Id>::This {} + ty::Alias(AliasKind::Projection, _) => ( + LocalImpl::Disallow { problematic_kind: "associated type" }, + NonlocalImpl::DisallowOther, + ), + + // type Opaque = impl Trait; + // impl AutoTrait for Opaque {} + ty::Alias(AliasKind::Opaque, _) => ( + LocalImpl::Disallow { problematic_kind: "opaque type" }, + NonlocalImpl::DisallowOther, + ), + + ty::Bool + | ty::Char + | ty::Int(..) + | ty::Uint(..) + | ty::Float(..) + | ty::Str + | ty::Array(..) + | ty::Slice(..) + | ty::RawPtr(..) + | ty::Ref(..) + | ty::FnDef(..) + | ty::FnPtr(..) + | ty::Never + | ty::Tuple(..) => (LocalImpl::Allow, NonlocalImpl::DisallowOther), + + ty::Closure(..) + | ty::Generator(..) + | ty::GeneratorWitness(..) + | ty::GeneratorWitnessMIR(..) + | ty::Bound(..) + | ty::Placeholder(..) + | ty::Infer(..) => { + let sp = tcx.def_span(def_id); + span_bug!(sp, "weird self type for autotrait impl") } - _ => Some(( - format!( - "cross-crate traits with a default impl, like `{}`, can \ - only be implemented for a struct/enum type, not `{}`", - tcx.def_path_str(trait_def_id), - self_ty - ), - "can't implement cross-crate trait with a default impl for \ - non-struct/enum type", - )), + + ty::Error(..) => (LocalImpl::Allow, NonlocalImpl::Allow), }; - if let Some((msg, label)) = msg { - let reported = - struct_span_err!(tcx.sess, sp, E0321, "{}", msg).span_label(sp, label).emit(); - return Err(reported); + if trait_def_id.is_local() { + match local_impl { + LocalImpl::Allow => {} + LocalImpl::Disallow { problematic_kind } => { + let msg = format!( + "traits with a default impl, like `{trait}`, \ + cannot be implemented for {problematic_kind} `{self_ty}`", + trait = tcx.def_path_str(trait_def_id), + ); + let label = format!( + "a trait object implements `{trait}` if and only if `{trait}` \ + is one of the trait object's trait bounds", + trait = tcx.def_path_str(trait_def_id), + ); + let sp = tcx.def_span(def_id); + let reported = + struct_span_err!(tcx.sess, sp, E0321, "{}", msg).note(label).emit(); + return Err(reported); + } + } + } else { + if let Some((msg, label)) = match nonlocal_impl { + NonlocalImpl::Allow => None, + NonlocalImpl::DisallowBecauseNonlocal => Some(( + format!( + "cross-crate traits with a default impl, like `{}`, \ + can only be implemented for a struct/enum type \ + defined in the current crate", + tcx.def_path_str(trait_def_id) + ), + "can't implement cross-crate trait for type in another crate", + )), + NonlocalImpl::DisallowOther => Some(( + format!( + "cross-crate traits with a default impl, like `{}`, can \ + only be implemented for a struct/enum type, not `{}`", + tcx.def_path_str(trait_def_id), + self_ty + ), + "can't implement cross-crate trait with a default impl for \ + non-struct/enum type", + )), + } { + let sp = tcx.def_span(def_id); + let reported = + struct_span_err!(tcx.sess, sp, E0321, "{}", msg).span_label(sp, label).emit(); + return Err(reported); + } } } @@ -381,7 +532,7 @@ fn lint_auto_trait_impl<'tcx>( }), |lint| { let item_span = tcx.def_span(self_type_did); - let self_descr = tcx.def_kind(self_type_did).descr(self_type_did); + let self_descr = tcx.def_descr(self_type_did); match arg { ty::util::NotUniqueParam::DuplicateParam(arg) => { lint.note(&format!("`{}` is mentioned multiple times", arg)); @@ -409,7 +560,7 @@ fn fast_reject_auto_impl<'tcx>(tcx: TyCtxt<'tcx>, trait_def_id: DefId, self_ty: seen: FxHashSet<DefId>, } - impl<'tcx> TypeVisitor<'tcx> for DisableAutoTraitVisitor<'tcx> { + impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for DisableAutoTraitVisitor<'tcx> { type BreakTy = (); fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> { let tcx = self.tcx; diff --git a/compiler/rustc_hir_analysis/src/coherence/unsafety.rs b/compiler/rustc_hir_analysis/src/coherence/unsafety.rs index fe6119dce..c6b161713 100644 --- a/compiler/rustc_hir_analysis/src/coherence/unsafety.rs +++ b/compiler/rustc_hir_analysis/src/coherence/unsafety.rs @@ -3,15 +3,13 @@ use rustc_errors::struct_span_err; use rustc_hir as hir; -use rustc_hir::def::DefKind; use rustc_hir::Unsafety; use rustc_middle::ty::TyCtxt; use rustc_span::def_id::LocalDefId; pub(super) fn check_item(tcx: TyCtxt<'_>, def_id: LocalDefId) { - debug_assert!(matches!(tcx.def_kind(def_id), DefKind::Impl)); let item = tcx.hir().expect_item(def_id); - let hir::ItemKind::Impl(impl_) = item.kind else { bug!() }; + let impl_ = item.expect_impl(); if let Some(trait_ref) = tcx.impl_trait_ref(item.owner_id) { let trait_ref = trait_ref.subst_identity(); |