diff options
Diffstat (limited to 'compiler/rustc_trait_selection')
4 files changed, 4 insertions, 179 deletions
diff --git a/compiler/rustc_trait_selection/src/solve/delegate.rs b/compiler/rustc_trait_selection/src/solve/delegate.rs index f67518a577e..ade26a40920 100644 --- a/compiler/rustc_trait_selection/src/solve/delegate.rs +++ b/compiler/rustc_trait_selection/src/solve/delegate.rs @@ -87,12 +87,12 @@ impl<'tcx> rustc_next_trait_solver::delegate::SolverDelegate for SolverDelegate< ) -> Option<ty::Const<'tcx>> { use rustc_middle::mir::interpret::ErrorHandled; match self.const_eval_resolve(param_env, unevaluated, DUMMY_SP) { - Ok(Some(val)) => Some(ty::Const::new_value( + Ok(Ok(val)) => Some(ty::Const::new_value( self.tcx, val, self.tcx.type_of(unevaluated.def).instantiate(self.tcx, unevaluated.args), )), - Ok(None) | Err(ErrorHandled::TooGeneric(_)) => None, + Ok(Err(_)) | Err(ErrorHandled::TooGeneric(_)) => None, Err(ErrorHandled::Reported(e, _)) => Some(ty::Const::new_error(self.tcx, e.into())), } } diff --git a/compiler/rustc_trait_selection/src/traits/auto_trait.rs b/compiler/rustc_trait_selection/src/traits/auto_trait.rs index 1d32ef2ccd9..796f7fd5a54 100644 --- a/compiler/rustc_trait_selection/src/traits/auto_trait.rs +++ b/compiler/rustc_trait_selection/src/traits/auto_trait.rs @@ -765,8 +765,8 @@ impl<'tcx> AutoTraitFinder<'tcx> { unevaluated, obligation.cause.span, ) { - Ok(Some(valtree)) => Ok(ty::Const::new_value(selcx.tcx(),valtree, self.tcx.type_of(unevaluated.def).instantiate(self.tcx, unevaluated.args))), - Ok(None) => { + Ok(Ok(valtree)) => Ok(ty::Const::new_value(selcx.tcx(),valtree, self.tcx.type_of(unevaluated.def).instantiate(self.tcx, unevaluated.args))), + Ok(Err(_)) => { let tcx = self.tcx; let reported = tcx.dcx().emit_err(UnableToConstructConstantValue { diff --git a/compiler/rustc_trait_selection/src/traits/mod.rs b/compiler/rustc_trait_selection/src/traits/mod.rs index d28982ed849..f7eb1730582 100644 --- a/compiler/rustc_trait_selection/src/traits/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/mod.rs @@ -16,7 +16,6 @@ pub mod query; #[allow(hidden_glob_reexports)] mod select; mod specialize; -mod structural_match; mod structural_normalize; #[allow(hidden_glob_reexports)] mod util; @@ -60,7 +59,6 @@ pub use self::specialize::specialization_graph::FutureCompatOverlapErrorKind; pub use self::specialize::{ specialization_graph, translate_args, translate_args_with_cause, OverlapError, }; -pub use self::structural_match::search_for_structural_match_violation; pub use self::structural_normalize::StructurallyNormalizeExt; pub use self::util::elaborate; pub use self::util::{expand_trait_aliases, TraitAliasExpander, TraitAliasExpansionInfo}; diff --git a/compiler/rustc_trait_selection/src/traits/structural_match.rs b/compiler/rustc_trait_selection/src/traits/structural_match.rs deleted file mode 100644 index d4535db951e..00000000000 --- a/compiler/rustc_trait_selection/src/traits/structural_match.rs +++ /dev/null @@ -1,173 +0,0 @@ -use rustc_data_structures::fx::FxHashSet; -use rustc_hir as hir; -use rustc_middle::bug; -use rustc_middle::ty::{self, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitor}; -use std::ops::ControlFlow; - -/// This method traverses the structure of `ty`, trying to find an -/// instance of an ADT (i.e. struct or enum) that doesn't implement -/// the structural-match traits, or a generic type parameter -/// (which cannot be determined to be structural-match). -/// -/// The "structure of a type" includes all components that would be -/// considered when doing a pattern match on a constant of that -/// type. -/// -/// * This means this method descends into fields of structs/enums, -/// and also descends into the inner type `T` of `&T` and `&mut T` -/// -/// * The traversal doesn't dereference unsafe pointers (`*const T`, -/// `*mut T`), and it does not visit the type arguments of an -/// instantiated generic like `PhantomData<T>`. -/// -/// The reason we do this search is Rust currently require all ADTs -/// reachable from a constant's type to implement the -/// structural-match traits, which essentially say that -/// the implementation of `PartialEq::eq` behaves *equivalently* to a -/// comparison against the unfolded structure. -/// -/// For more background on why Rust has this requirement, and issues -/// that arose when the requirement was not enforced completely, see -/// Rust RFC 1445, rust-lang/rust#61188, and rust-lang/rust#62307. -pub fn search_for_structural_match_violation<'tcx>( - tcx: TyCtxt<'tcx>, - ty: Ty<'tcx>, -) -> Option<Ty<'tcx>> { - ty.visit_with(&mut Search { tcx, seen: FxHashSet::default() }).break_value() -} - -/// This implements the traversal over the structure of a given type to try to -/// find instances of ADTs (specifically structs or enums) that do not implement -/// `StructuralPartialEq`. -struct Search<'tcx> { - tcx: TyCtxt<'tcx>, - - /// Tracks ADTs previously encountered during search, so that - /// we will not recur on them again. - seen: FxHashSet<hir::def_id::DefId>, -} - -impl<'tcx> Search<'tcx> { - fn type_marked_structural(&self, adt_ty: Ty<'tcx>) -> bool { - adt_ty.is_structural_eq_shallow(self.tcx) - } -} - -impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for Search<'tcx> { - type Result = ControlFlow<Ty<'tcx>>; - - fn visit_ty(&mut self, ty: Ty<'tcx>) -> Self::Result { - debug!("Search visiting ty: {:?}", ty); - - let (adt_def, args) = match *ty.kind() { - ty::Adt(adt_def, args) => (adt_def, args), - ty::Param(_) => { - return ControlFlow::Break(ty); - } - ty::Dynamic(..) => { - return ControlFlow::Break(ty); - } - ty::Foreign(_) => { - return ControlFlow::Break(ty); - } - ty::Alias(..) => { - return ControlFlow::Break(ty); - } - ty::Closure(..) => { - return ControlFlow::Break(ty); - } - ty::CoroutineClosure(..) => { - return ControlFlow::Break(ty); - } - ty::Coroutine(..) | ty::CoroutineWitness(..) => { - return ControlFlow::Break(ty); - } - ty::FnDef(..) => { - // Types of formals and return in `fn(_) -> _` are also irrelevant; - // so we do not recur into them via `super_visit_with` - return ControlFlow::Continue(()); - } - ty::Array(_, n) - if { n.try_eval_target_usize(self.tcx, ty::ParamEnv::reveal_all()) == Some(0) } => - { - // rust-lang/rust#62336: ignore type of contents - // for empty array. - return ControlFlow::Continue(()); - } - ty::Bool | ty::Char | ty::Int(_) | ty::Uint(_) | ty::Str | ty::Never => { - // These primitive types are always structural match. - // - // `Never` is kind of special here, but as it is not inhabitable, this should be fine. - return ControlFlow::Continue(()); - } - - ty::FnPtr(..) => { - return ControlFlow::Continue(()); - } - - ty::RawPtr(..) => { - // structural-match ignores substructure of - // `*const _`/`*mut _`, so skip `super_visit_with`. - // - // For example, if you have: - // ``` - // struct NonStructural; - // #[derive(PartialEq, Eq)] - // struct T(*const NonStructural); - // const C: T = T(std::ptr::null()); - // ``` - // - // Even though `NonStructural` does not implement `PartialEq`, - // structural equality on `T` does not recur into the raw - // pointer. Therefore, one can still use `C` in a pattern. - return ControlFlow::Continue(()); - } - - ty::Float(_) => { - return ControlFlow::Continue(()); - } - - ty::Pat(..) | ty::Array(..) | ty::Slice(_) | ty::Ref(..) | ty::Tuple(..) => { - // First check all contained types and then tell the caller to continue searching. - return ty.super_visit_with(self); - } - ty::Infer(_) | ty::Placeholder(_) | ty::Bound(..) => { - bug!("unexpected type during structural-match checking: {:?}", ty); - } - ty::Error(_) => { - // We still want to check other types after encountering an error, - // as this may still emit relevant errors. - return ControlFlow::Continue(()); - } - }; - - if !self.seen.insert(adt_def.did()) { - debug!("Search already seen adt_def: {:?}", adt_def); - return ControlFlow::Continue(()); - } - - if !self.type_marked_structural(ty) { - debug!("Search found ty: {:?}", ty); - return ControlFlow::Break(ty); - } - - // structural-match does not care about the - // instantiation of the generics in an ADT (it - // instead looks directly at its fields outside - // this match), so we skip super_visit_with. - // - // (Must not recur on args for `PhantomData<T>` cf - // rust-lang/rust#55028 and rust-lang/rust#55837; but also - // want to skip args when only uses of generic are - // behind unsafe pointers `*const T`/`*mut T`.) - - // even though we skip super_visit_with, we must recur on - // fields of ADT. - let tcx = self.tcx; - adt_def.all_fields().map(|field| field.ty(tcx, args)).try_for_each(|field_ty| { - let ty = self.tcx.normalize_erasing_regions(ty::ParamEnv::empty(), field_ty); - debug!("structural-match ADT: field_ty={:?}, ty={:?}", field_ty, ty); - ty.visit_with(self) - }) - } -} |