diff options
17 files changed, 360 insertions, 245 deletions
diff --git a/compiler/rustc_next_trait_solver/src/solve/assembly/mod.rs b/compiler/rustc_next_trait_solver/src/solve/assembly/mod.rs index a3274fb4011..b0f59ed1474 100644 --- a/compiler/rustc_next_trait_solver/src/solve/assembly/mod.rs +++ b/compiler/rustc_next_trait_solver/src/solve/assembly/mod.rs @@ -6,7 +6,6 @@ use derive_where::derive_where; use rustc_type_ir::fold::TypeFoldable; use rustc_type_ir::inherent::*; use rustc_type_ir::lang_items::TraitSolverLangItem; -use rustc_type_ir::solve::inspect; use rustc_type_ir::visit::TypeVisitableExt as _; use rustc_type_ir::{self as ty, Interner, TypingMode, Upcast as _, elaborate}; use tracing::{debug, instrument}; @@ -297,25 +296,6 @@ where let Ok(normalized_self_ty) = self.structurally_normalize_ty(goal.param_env, goal.predicate.self_ty()) else { - // FIXME: We register a fake candidate when normalization fails so that - // we can point at the reason for *why*. I'm tempted to say that this - // is the wrong way to do this, though. - let result = - self.probe(|&result| inspect::ProbeKind::RigidAlias { result }).enter(|this| { - let normalized_ty = this.next_ty_infer(); - let alias_relate_goal = Goal::new( - this.cx(), - goal.param_env, - ty::PredicateKind::AliasRelate( - goal.predicate.self_ty().into(), - normalized_ty.into(), - ty::AliasRelationDirection::Equate, - ), - ); - this.add_goal(GoalSource::AliasWellFormed, alias_relate_goal); - this.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS) - }); - assert_eq!(result, Err(NoSolution)); return vec![]; }; @@ -797,11 +777,12 @@ where /// treat the alias as rigid. /// /// See trait-system-refactor-initiative#124 for more details. - #[instrument(level = "debug", skip(self), ret)] + #[instrument(level = "debug", skip(self, inject_normalize_to_rigid_candidate), ret)] pub(super) fn merge_candidates( &mut self, proven_via: Option<TraitGoalProvenVia>, candidates: Vec<Candidate<I>>, + inject_normalize_to_rigid_candidate: impl FnOnce(&mut EvalCtxt<'_, D>) -> QueryResult<I>, ) -> QueryResult<I> { let Some(proven_via) = proven_via else { // We don't care about overflow. If proving the trait goal overflowed, then @@ -818,13 +799,27 @@ where // FIXME(const_trait_impl): should this behavior also be used by // constness checking. Doing so is *at least theoretically* breaking, // see github.com/rust-lang/rust/issues/133044#issuecomment-2500709754 - TraitGoalProvenVia::ParamEnv | TraitGoalProvenVia::AliasBound => candidates - .iter() - .filter(|c| { - matches!(c.source, CandidateSource::AliasBound | CandidateSource::ParamEnv(_)) - }) - .map(|c| c.result) - .collect(), + TraitGoalProvenVia::ParamEnv | TraitGoalProvenVia::AliasBound => { + let mut candidates_from_env: Vec<_> = candidates + .iter() + .filter(|c| { + matches!( + c.source, + CandidateSource::AliasBound | CandidateSource::ParamEnv(_) + ) + }) + .map(|c| c.result) + .collect(); + + // If the trait goal has been proven by using the environment, we want to treat + // aliases as rigid if there are no applicable projection bounds in the environment. + if candidates_from_env.is_empty() { + if let Ok(response) = inject_normalize_to_rigid_candidate(self) { + candidates_from_env.push(response); + } + } + candidates_from_env + } TraitGoalProvenVia::Misc => candidates.iter().map(|c| c.result).collect(), }; diff --git a/compiler/rustc_next_trait_solver/src/solve/effect_goals.rs b/compiler/rustc_next_trait_solver/src/solve/effect_goals.rs index eb398e8724d..0b61c368d8e 100644 --- a/compiler/rustc_next_trait_solver/src/solve/effect_goals.rs +++ b/compiler/rustc_next_trait_solver/src/solve/effect_goals.rs @@ -405,6 +405,6 @@ where goal.with(ecx.cx(), goal.predicate.trait_ref); ecx.compute_trait_goal(trait_goal) })?; - self.merge_candidates(proven_via, candidates) + self.merge_candidates(proven_via, candidates, |_ecx| Err(NoSolution)) } } diff --git a/compiler/rustc_next_trait_solver/src/solve/normalizes_to/mod.rs b/compiler/rustc_next_trait_solver/src/solve/normalizes_to/mod.rs index 1d0ec7b45ca..88002e1a88a 100644 --- a/compiler/rustc_next_trait_solver/src/solve/normalizes_to/mod.rs +++ b/compiler/rustc_next_trait_solver/src/solve/normalizes_to/mod.rs @@ -30,75 +30,26 @@ where ) -> QueryResult<I> { self.set_is_normalizes_to_goal(); debug_assert!(self.term_is_fully_unconstrained(goal)); - let normalize_result = self - .probe(|&result| ProbeKind::TryNormalizeNonRigid { result }) - .enter(|this| this.normalize_at_least_one_step(goal)); - - match normalize_result { - Ok(res) => Ok(res), - Err(NoSolution) => { - self.probe(|&result| ProbeKind::RigidAlias { result }).enter(|this| { - let Goal { param_env, predicate: NormalizesTo { alias, term } } = goal; - this.add_rigid_constraints(param_env, alias)?; - this.relate_rigid_alias_non_alias(param_env, alias, ty::Invariant, term)?; - this.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) - }) - } - } - } - - /// Register any obligations that are used to validate that an alias should be - /// treated as rigid. - /// - /// An alias may be considered rigid if it fails normalization, but we also don't - /// want to consider aliases that are not well-formed to be rigid simply because - /// they fail normalization. - /// - /// For example, some `<T as Trait>::Assoc` where `T: Trait` does not hold, or an - /// opaque type whose hidden type doesn't actually satisfy the opaque item bounds. - fn add_rigid_constraints( - &mut self, - param_env: I::ParamEnv, - rigid_alias: ty::AliasTerm<I>, - ) -> Result<(), NoSolution> { - let cx = self.cx(); - match rigid_alias.kind(cx) { - // Projections are rigid only if their trait ref holds, - // and the GAT where-clauses hold. - ty::AliasTermKind::ProjectionTy | ty::AliasTermKind::ProjectionConst => { - let trait_ref = rigid_alias.trait_ref(cx); - self.add_goal(GoalSource::AliasWellFormed, Goal::new(cx, param_env, trait_ref)); - Ok(()) - } - ty::AliasTermKind::OpaqueTy => { - if self.opaque_type_is_rigid(rigid_alias.def_id) { - Ok(()) - } else { - Err(NoSolution) - } - } - // FIXME(generic_const_exprs): we would need to support generic consts here - ty::AliasTermKind::UnevaluatedConst => Err(NoSolution), - // Inherent and weak types are never rigid. This type must not be well-formed. - ty::AliasTermKind::WeakTy | ty::AliasTermKind::InherentTy => Err(NoSolution), - } - } - - /// Normalize the given alias by at least one step. If the alias is rigid, this - /// returns `NoSolution`. - #[instrument(level = "trace", skip(self), ret)] - fn normalize_at_least_one_step(&mut self, goal: Goal<I, NormalizesTo<I>>) -> QueryResult<I> { let cx = self.cx(); match goal.predicate.alias.kind(cx) { ty::AliasTermKind::ProjectionTy | ty::AliasTermKind::ProjectionConst => { let candidates = self.assemble_and_evaluate_candidates(goal); + let trait_ref = goal.predicate.alias.trait_ref(cx); let (_, proven_via) = self.probe(|_| ProbeKind::ShadowedEnvProbing).enter(|ecx| { - let trait_goal: Goal<I, ty::TraitPredicate<I>> = - goal.with(cx, goal.predicate.alias.trait_ref(cx)); + let trait_goal: Goal<I, ty::TraitPredicate<I>> = goal.with(cx, trait_ref); ecx.compute_trait_goal(trait_goal) })?; - self.merge_candidates(proven_via, candidates) + self.merge_candidates(proven_via, candidates, |ecx| { + ecx.probe(|&result| ProbeKind::RigidAlias { result }).enter(|this| { + this.structurally_instantiate_normalizes_to_term( + goal, + goal.predicate.alias, + ); + this.add_goal(GoalSource::AliasWellFormed, goal.with(cx, trait_ref)); + this.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + }) + }) } ty::AliasTermKind::InherentTy => self.normalize_inherent_associated_type(goal), ty::AliasTermKind::OpaqueTy => self.normalize_opaque_type(goal), @@ -120,6 +71,17 @@ where self.eq(goal.param_env, goal.predicate.term, term) .expect("expected goal term to be fully unconstrained"); } + + /// Unlike `instantiate_normalizes_to_term` this instantiates the expected term + /// with a rigid alias. Using this is pretty much always wrong. + pub fn structurally_instantiate_normalizes_to_term( + &mut self, + goal: Goal<I, NormalizesTo<I>>, + term: ty::AliasTerm<I>, + ) { + self.relate_rigid_alias_non_alias(goal.param_env, term, ty::Invariant, goal.predicate.term) + .expect("expected goal term to be fully unconstrained"); + } } impl<D, I> assembly::GoalKind<D> for NormalizesTo<I> @@ -576,80 +538,92 @@ where let cx = ecx.cx(); let metadata_def_id = cx.require_lang_item(TraitSolverLangItem::Metadata); assert_eq!(metadata_def_id, goal.predicate.def_id()); - ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc).enter(|ecx| { - let metadata_ty = match goal.predicate.self_ty().kind() { - ty::Bool - | ty::Char - | ty::Int(..) - | ty::Uint(..) - | ty::Float(..) - | ty::Array(..) - | ty::Pat(..) - | ty::RawPtr(..) - | ty::Ref(..) - | ty::FnDef(..) - | ty::FnPtr(..) - | ty::Closure(..) - | ty::CoroutineClosure(..) - | ty::Infer(ty::IntVar(..) | ty::FloatVar(..)) - | ty::Coroutine(..) - | ty::CoroutineWitness(..) - | ty::Never - | ty::Foreign(..) - | ty::Dynamic(_, _, ty::DynStar) => Ty::new_unit(cx), - - ty::Error(e) => Ty::new_error(cx, e), - - ty::Str | ty::Slice(_) => Ty::new_usize(cx), - - ty::Dynamic(_, _, ty::Dyn) => { - let dyn_metadata = cx.require_lang_item(TraitSolverLangItem::DynMetadata); - cx.type_of(dyn_metadata) - .instantiate(cx, &[I::GenericArg::from(goal.predicate.self_ty())]) - } + let metadata_ty = match goal.predicate.self_ty().kind() { + ty::Bool + | ty::Char + | ty::Int(..) + | ty::Uint(..) + | ty::Float(..) + | ty::Array(..) + | ty::Pat(..) + | ty::RawPtr(..) + | ty::Ref(..) + | ty::FnDef(..) + | ty::FnPtr(..) + | ty::Closure(..) + | ty::CoroutineClosure(..) + | ty::Infer(ty::IntVar(..) | ty::FloatVar(..)) + | ty::Coroutine(..) + | ty::CoroutineWitness(..) + | ty::Never + | ty::Foreign(..) + | ty::Dynamic(_, _, ty::DynStar) => Ty::new_unit(cx), - ty::Alias(_, _) | ty::Param(_) | ty::Placeholder(..) => { - // This is the "fallback impl" for type parameters, unnormalizable projections - // and opaque types: If the `self_ty` is `Sized`, then the metadata is `()`. - // FIXME(ptr_metadata): This impl overlaps with the other impls and shouldn't - // exist. Instead, `Pointee<Metadata = ()>` should be a supertrait of `Sized`. - let sized_predicate = ty::TraitRef::new( - cx, - cx.require_lang_item(TraitSolverLangItem::Sized), - [I::GenericArg::from(goal.predicate.self_ty())], - ); - // FIXME(-Znext-solver=coinductive): Should this be `GoalSource::ImplWhereBound`? - ecx.add_goal(GoalSource::Misc, goal.with(cx, sized_predicate)); - Ty::new_unit(cx) - } + ty::Error(e) => Ty::new_error(cx, e), - ty::Adt(def, args) if def.is_struct() => match def.struct_tail_ty(cx) { - None => Ty::new_unit(cx), - Some(tail_ty) => { - Ty::new_projection(cx, metadata_def_id, [tail_ty.instantiate(cx, args)]) - } - }, - ty::Adt(_, _) => Ty::new_unit(cx), + ty::Str | ty::Slice(_) => Ty::new_usize(cx), - ty::Tuple(elements) => match elements.last() { - None => Ty::new_unit(cx), - Some(tail_ty) => Ty::new_projection(cx, metadata_def_id, [tail_ty]), - }, + ty::Dynamic(_, _, ty::Dyn) => { + let dyn_metadata = cx.require_lang_item(TraitSolverLangItem::DynMetadata); + cx.type_of(dyn_metadata) + .instantiate(cx, &[I::GenericArg::from(goal.predicate.self_ty())]) + } + + ty::Alias(_, _) | ty::Param(_) | ty::Placeholder(..) => { + // This is the "fallback impl" for type parameters, unnormalizable projections + // and opaque types: If the `self_ty` is `Sized`, then the metadata is `()`. + // FIXME(ptr_metadata): This impl overlaps with the other impls and shouldn't + // exist. Instead, `Pointee<Metadata = ()>` should be a supertrait of `Sized`. + let alias_bound_result = + ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc).enter(|ecx| { + let sized_predicate = ty::TraitRef::new( + cx, + cx.require_lang_item(TraitSolverLangItem::Sized), + [I::GenericArg::from(goal.predicate.self_ty())], + ); + ecx.add_goal(GoalSource::Misc, goal.with(cx, sized_predicate)); + ecx.instantiate_normalizes_to_term(goal, Ty::new_unit(cx).into()); + ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + }); + // In case the dummy alias-bound candidate does not apply, we instead treat this projection + // as rigid. + return alias_bound_result.or_else(|NoSolution| { + ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc).enter(|this| { + this.structurally_instantiate_normalizes_to_term( + goal, + goal.predicate.alias, + ); + this.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + }) + }); + } - ty::UnsafeBinder(_) => { - // FIXME(unsafe_binder): Figure out how to handle pointee for unsafe binders. - todo!() + ty::Adt(def, args) if def.is_struct() => match def.struct_tail_ty(cx) { + None => Ty::new_unit(cx), + Some(tail_ty) => { + Ty::new_projection(cx, metadata_def_id, [tail_ty.instantiate(cx, args)]) } + }, + ty::Adt(_, _) => Ty::new_unit(cx), - ty::Infer( - ty::TyVar(_) | ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_), - ) - | ty::Bound(..) => panic!( - "unexpected self ty `{:?}` when normalizing `<T as Pointee>::Metadata`", - goal.predicate.self_ty() - ), - }; + ty::Tuple(elements) => match elements.last() { + None => Ty::new_unit(cx), + Some(tail_ty) => Ty::new_projection(cx, metadata_def_id, [tail_ty]), + }, + ty::UnsafeBinder(_) => { + // FIXME(unsafe_binder): Figure out how to handle pointee for unsafe binders. + todo!() + } + + ty::Infer(ty::TyVar(_) | ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_)) + | ty::Bound(..) => panic!( + "unexpected self ty `{:?}` when normalizing `<T as Pointee>::Metadata`", + goal.predicate.self_ty() + ), + }; + + ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc).enter(|ecx| { ecx.instantiate_normalizes_to_term(goal, metadata_ty.into()); ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) }) @@ -850,12 +824,14 @@ where todo!("discr subgoal...") } - // We do not call `Ty::discriminant_ty` on alias, param, or placeholder - // types, which return `<self_ty as DiscriminantKind>::Discriminant` - // (or ICE in the case of placeholders). Projecting a type to itself - // is never really productive. + // Given an alias, parameter, or placeholder we add an impl candidate normalizing to a rigid + // alias. In case there's a where-bound further constraining this alias it is preferred over + // this impl candidate anyways. It's still a bit scuffed. ty::Alias(_, _) | ty::Param(_) | ty::Placeholder(..) => { - return Err(NoSolution); + return ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc).enter(|ecx| { + ecx.structurally_instantiate_normalizes_to_term(goal, goal.predicate.alias); + ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + }); } ty::Infer(ty::TyVar(_) | ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_)) @@ -902,12 +878,14 @@ where todo!() } - // We do not call `Ty::async_destructor_ty` on alias, param, or placeholder - // types, which return `<self_ty as AsyncDestruct>::AsyncDestructor` - // (or ICE in the case of placeholders). Projecting a type to itself - // is never really productive. + // Given an alias, parameter, or placeholder we add an impl candidate normalizing to a rigid + // alias. In case there's a where-bound further constraining this alias it is preferred over + // this impl candidate anyways. It's still a bit scuffed. ty::Alias(_, _) | ty::Param(_) | ty::Placeholder(..) => { - return Err(NoSolution); + return ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc).enter(|ecx| { + ecx.structurally_instantiate_normalizes_to_term(goal, goal.predicate.alias); + ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + }); } ty::Infer(ty::TyVar(_) | ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_)) diff --git a/compiler/rustc_next_trait_solver/src/solve/normalizes_to/opaque_types.rs b/compiler/rustc_next_trait_solver/src/solve/normalizes_to/opaque_types.rs index 26a8a22d77e..60c20762a30 100644 --- a/compiler/rustc_next_trait_solver/src/solve/normalizes_to/opaque_types.rs +++ b/compiler/rustc_next_trait_solver/src/solve/normalizes_to/opaque_types.rs @@ -35,14 +35,15 @@ where self.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS) } TypingMode::Analysis { defining_opaque_types } => { - let Some(def_id) = opaque_ty.def_id.as_local() else { - return Err(NoSolution); + let Some(def_id) = opaque_ty + .def_id + .as_local() + .filter(|&def_id| defining_opaque_types.contains(&def_id)) + else { + self.structurally_instantiate_normalizes_to_term(goal, goal.predicate.alias); + return self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes); }; - if !defining_opaque_types.contains(&def_id) { - return Err(NoSolution); - } - // FIXME: This may have issues when the args contain aliases... match uses_unique_placeholders_ignoring_regions(self.cx(), opaque_ty.args) { Err(NotUniqueParam::NotParam(param)) if param.is_non_region_infer() => { @@ -97,15 +98,16 @@ where self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) } TypingMode::PostBorrowckAnalysis { defined_opaque_types } => { - let Some(def_id) = opaque_ty.def_id.as_local() else { - return Err(NoSolution); + let Some(def_id) = opaque_ty + .def_id + .as_local() + .filter(|&def_id| defined_opaque_types.contains(&def_id)) + else { + self.structurally_instantiate_normalizes_to_term(goal, goal.predicate.alias); + return self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes); }; - if !defined_opaque_types.contains(&def_id) { - return Err(NoSolution); - } - - let actual = cx.type_of(opaque_ty.def_id).instantiate(cx, opaque_ty.args); + let actual = cx.type_of(def_id.into()).instantiate(cx, opaque_ty.args); // FIXME: Actually use a proper binder here instead of relying on `ReErased`. // // This is also probably unsound or sth :shrug: diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs index 1b43820bac0..49fa21e50c0 100644 --- a/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs +++ b/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs @@ -585,6 +585,10 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> { ty::PredicateKind::Clause(ty::ClauseKind::WellFormed(ty)) => { let ty = self.resolve_vars_if_possible(ty); if self.next_trait_solver() { + if let Err(guar) = ty.error_reported() { + return guar; + } + // FIXME: we'll need a better message which takes into account // which bounds actually failed to hold. self.dcx().struct_span_err( diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/mod.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/mod.rs index 658fb4009d5..e4f250ca4f5 100644 --- a/compiler/rustc_trait_selection/src/error_reporting/traits/mod.rs +++ b/compiler/rustc_trait_selection/src/error_reporting/traits/mod.rs @@ -172,8 +172,8 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> { { 1 } - ty::PredicateKind::Clause(ty::ClauseKind::WellFormed(_)) => 3, ty::PredicateKind::Coerce(_) => 2, + ty::PredicateKind::Clause(ty::ClauseKind::WellFormed(_)) => 3, _ => 0, }); diff --git a/compiler/rustc_trait_selection/src/solve/fulfill/derive_errors.rs b/compiler/rustc_trait_selection/src/solve/fulfill/derive_errors.rs index 7364b4aa343..982782bc57c 100644 --- a/compiler/rustc_trait_selection/src/solve/fulfill/derive_errors.rs +++ b/compiler/rustc_trait_selection/src/solve/fulfill/derive_errors.rs @@ -7,7 +7,7 @@ use rustc_infer::traits::{ PredicateObligation, SelectionError, }; use rustc_middle::ty::error::{ExpectedFound, TypeError}; -use rustc_middle::ty::{self, TyCtxt}; +use rustc_middle::ty::{self, Ty, TyCtxt}; use rustc_middle::{bug, span_bug}; use rustc_next_trait_solver::solve::{GenerateProofTree, SolverDelegateEvalExt as _}; use rustc_type_ir::solve::{Goal, NoSolution}; @@ -139,6 +139,7 @@ pub(super) fn fulfillment_error_for_overflow<'tcx>( } } +#[instrument(level = "debug", skip(infcx), ret)] fn find_best_leaf_obligation<'tcx>( infcx: &InferCtxt<'tcx>, obligation: &PredicateObligation<'tcx>, @@ -197,6 +198,9 @@ impl<'tcx> BestObligation<'tcx> { candidates.retain(|candidate| candidate.result().is_ok()); } false => { + // We always handle rigid alias candidates separately as we may not add them for + // aliases whose trait bound doesn't hold. + candidates.retain(|c| !matches!(c.kind(), inspect::ProbeKind::RigidAlias { .. })); // If we have >1 candidate, one may still be due to "boring" reasons, like // an alias-relate that failed to hold when deeply evaluated. We really // don't care about reasons like this. @@ -211,23 +215,12 @@ impl<'tcx> BestObligation<'tcx> { | GoalSource::AliasBoundConstCondition | GoalSource::InstantiateHigherRanked | GoalSource::AliasWellFormed - ) && match (self.consider_ambiguities, nested_goal.result()) { - (true, Ok(Certainty::Maybe(MaybeCause::Ambiguity))) - | (false, Err(_)) => true, - _ => false, - } + ) && nested_goal.result().is_err() }, ) }) }); } - - // Prefer a non-rigid candidate if there is one. - if candidates.len() > 1 { - candidates.retain(|candidate| { - !matches!(candidate.kind(), inspect::ProbeKind::RigidAlias { .. }) - }); - } } } @@ -266,6 +259,90 @@ impl<'tcx> BestObligation<'tcx> { ControlFlow::Break(self.obligation.clone()) } + + /// If a normalization of an associated item or a trait goal fails without trying any + /// candidates it's likely that normalizing its self type failed. We manually detect + /// such cases here. + fn detect_error_in_self_ty_normalization( + &mut self, + goal: &inspect::InspectGoal<'_, 'tcx>, + self_ty: Ty<'tcx>, + ) -> ControlFlow<PredicateObligation<'tcx>> { + assert!(!self.consider_ambiguities); + let tcx = goal.infcx().tcx; + if let ty::Alias(..) = self_ty.kind() { + let infer_term = goal.infcx().next_ty_var(self.obligation.cause.span); + let pred = ty::PredicateKind::AliasRelate( + self_ty.into(), + infer_term.into(), + ty::AliasRelationDirection::Equate, + ); + let obligation = + Obligation::new(tcx, self.obligation.cause.clone(), goal.goal().param_env, pred); + self.with_derived_obligation(obligation, |this| { + goal.infcx().visit_proof_tree_at_depth( + goal.goal().with(tcx, pred), + goal.depth() + 1, + this, + ) + }) + } else { + ControlFlow::Continue(()) + } + } + + /// It is likely that `NormalizesTo` failed without any applicable candidates + /// because the alias is not well-formed. + /// + /// As we only enter `RigidAlias` candidates if the trait bound of the associated type + /// holds, we discard these candidates in `non_trivial_candidates` and always manually + /// check this here. + fn detect_non_well_formed_assoc_item( + &mut self, + goal: &inspect::InspectGoal<'_, 'tcx>, + alias: ty::AliasTerm<'tcx>, + ) -> ControlFlow<PredicateObligation<'tcx>> { + let tcx = goal.infcx().tcx; + let obligation = Obligation::new( + tcx, + self.obligation.cause.clone(), + goal.goal().param_env, + alias.trait_ref(tcx), + ); + self.with_derived_obligation(obligation, |this| { + goal.infcx().visit_proof_tree_at_depth( + goal.goal().with(tcx, alias.trait_ref(tcx)), + goal.depth() + 1, + this, + ) + }) + } + + /// If we have no candidates, then it's likely that there is a + /// non-well-formed alias in the goal. + fn detect_error_from_empty_candidates( + &mut self, + goal: &inspect::InspectGoal<'_, 'tcx>, + ) -> ControlFlow<PredicateObligation<'tcx>> { + let tcx = goal.infcx().tcx; + let pred_kind = goal.goal().predicate.kind(); + + match pred_kind.no_bound_vars() { + Some(ty::PredicateKind::Clause(ty::ClauseKind::Trait(pred))) => { + self.detect_error_in_self_ty_normalization(goal, pred.self_ty())?; + } + Some(ty::PredicateKind::NormalizesTo(pred)) + if let ty::AliasTermKind::ProjectionTy | ty::AliasTermKind::ProjectionConst = + pred.alias.kind(tcx) => + { + self.detect_error_in_self_ty_normalization(goal, pred.alias.self_ty())?; + self.detect_non_well_formed_assoc_item(goal, pred.alias)?; + } + Some(_) | None => {} + } + + ControlFlow::Break(self.obligation.clone()) + } } impl<'tcx> ProofTreeVisitor<'tcx> for BestObligation<'tcx> { @@ -277,11 +354,19 @@ impl<'tcx> ProofTreeVisitor<'tcx> for BestObligation<'tcx> { #[instrument(level = "trace", skip(self, goal), fields(goal = ?goal.goal()))] fn visit_goal(&mut self, goal: &inspect::InspectGoal<'_, 'tcx>) -> Self::Result { - let candidates = self.non_trivial_candidates(goal); - trace!(candidates = ?candidates.iter().map(|c| c.kind()).collect::<Vec<_>>()); + let tcx = goal.infcx().tcx; + // Skip goals that aren't the *reason* for our goal's failure. + match (self.consider_ambiguities, goal.result()) { + (true, Ok(Certainty::Maybe(MaybeCause::Ambiguity))) | (false, Err(_)) => {} + _ => return ControlFlow::Continue(()), + } + let pred_kind = goal.goal().predicate.kind(); - let [candidate] = candidates.as_slice() else { - return ControlFlow::Break(self.obligation.clone()); + let candidates = self.non_trivial_candidates(goal); + let candidate = match candidates.as_slice() { + [candidate] => candidate, + [] => return self.detect_error_from_empty_candidates(goal), + _ => return ControlFlow::Break(self.obligation.clone()), }; // Don't walk into impls that have `do_not_recommend`. @@ -291,13 +376,12 @@ impl<'tcx> ProofTreeVisitor<'tcx> for BestObligation<'tcx> { } = candidate.kind() && goal.infcx().tcx.do_not_recommend_impl(impl_def_id) { + trace!("#[do_not_recommend] -> exit"); return ControlFlow::Break(self.obligation.clone()); } - let tcx = goal.infcx().tcx; // FIXME: Also, what about considering >1 layer up the stack? May be necessary // for normalizes-to. - let pred_kind = goal.goal().predicate.kind(); let child_mode = match pred_kind.skip_binder() { ty::PredicateKind::Clause(ty::ClauseKind::Trait(pred)) => { ChildMode::Trait(pred_kind.rebind(pred)) @@ -390,12 +474,6 @@ impl<'tcx> ProofTreeVisitor<'tcx> for BestObligation<'tcx> { } } - // Skip nested goals that aren't the *reason* for our goal's failure. - match (self.consider_ambiguities, nested_goal.result()) { - (true, Ok(Certainty::Maybe(MaybeCause::Ambiguity))) | (false, Err(_)) => {} - _ => continue, - } - self.with_derived_obligation(obligation, |this| nested_goal.visit_with(this))?; } diff --git a/compiler/rustc_trait_selection/src/solve/inspect/analyse.rs b/compiler/rustc_trait_selection/src/solve/inspect/analyse.rs index 9f4ee54bd4c..9fbc1d64d74 100644 --- a/compiler/rustc_trait_selection/src/solve/inspect/analyse.rs +++ b/compiler/rustc_trait_selection/src/solve/inspect/analyse.rs @@ -300,7 +300,6 @@ impl<'a, 'tcx> InspectGoal<'a, 'tcx> { inspect::ProbeKind::NormalizedSelfTyAssembly | inspect::ProbeKind::UnsizeAssembly | inspect::ProbeKind::Root { .. } - | inspect::ProbeKind::TryNormalizeNonRigid { .. } | inspect::ProbeKind::TraitCandidate { .. } | inspect::ProbeKind::OpaqueTypeStorageLookup { .. } | inspect::ProbeKind::RigidAlias { .. } => { @@ -325,7 +324,6 @@ impl<'a, 'tcx> InspectGoal<'a, 'tcx> { // We add a candidate even for the root evaluation if there // is only one way to prove a given goal, e.g. for `WellFormed`. inspect::ProbeKind::Root { result } - | inspect::ProbeKind::TryNormalizeNonRigid { result } | inspect::ProbeKind::TraitCandidate { source: _, result } | inspect::ProbeKind::OpaqueTypeStorageLookup { result } | inspect::ProbeKind::RigidAlias { result } => { diff --git a/compiler/rustc_trait_selection/src/solve/select.rs b/compiler/rustc_trait_selection/src/solve/select.rs index b0b6274907d..4437fc5b029 100644 --- a/compiler/rustc_trait_selection/src/solve/select.rs +++ b/compiler/rustc_trait_selection/src/solve/select.rs @@ -175,8 +175,7 @@ fn to_selection<'tcx>( span_bug!(span, "didn't expect to select an unknowable candidate") } }, - ProbeKind::TryNormalizeNonRigid { result: _ } - | ProbeKind::NormalizedSelfTyAssembly + ProbeKind::NormalizedSelfTyAssembly | ProbeKind::UnsizeAssembly | ProbeKind::UpcastProjectionCompatibility | ProbeKind::OpaqueTypeStorageLookup { result: _ } diff --git a/compiler/rustc_type_ir/src/solve/inspect.rs b/compiler/rustc_type_ir/src/solve/inspect.rs index d0e618dc6f9..18fb71dd290 100644 --- a/compiler/rustc_type_ir/src/solve/inspect.rs +++ b/compiler/rustc_type_ir/src/solve/inspect.rs @@ -111,8 +111,6 @@ pub enum ProbeStep<I: Interner> { pub enum ProbeKind<I: Interner> { /// The root inference context while proving a goal. Root { result: QueryResult<I> }, - /// Trying to normalize an alias by at least one step in `NormalizesTo`. - TryNormalizeNonRigid { result: QueryResult<I> }, /// Probe entered when normalizing the self ty during candidate assembly NormalizedSelfTyAssembly, /// A candidate for proving a trait or alias-relate goal. diff --git a/tests/crashes/134905.rs b/tests/crashes/134905.rs deleted file mode 100644 index 9f0f0f4b3f2..00000000000 --- a/tests/crashes/134905.rs +++ /dev/null @@ -1,16 +0,0 @@ -//@ known-bug: #134905 - -trait Iterate<'a> { - type Ty: Valid; -} -impl<'a, T> Iterate<'a> for T -where - T: Check, -{ - default type Ty = (); -} - -trait Check {} -impl<'a, T> Eq for T where <T as Iterate<'a>>::Ty: Valid {} - -trait Valid {} diff --git a/tests/ui/auto-traits/assoc-ty.next.stderr b/tests/ui/auto-traits/assoc-ty.next.stderr index b9f56d6c99c..4ce00d17475 100644 --- a/tests/ui/auto-traits/assoc-ty.next.stderr +++ b/tests/ui/auto-traits/assoc-ty.next.stderr @@ -21,20 +21,21 @@ LL | | } = help: add `#![feature(auto_traits)]` to the crate attributes to enable = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date -error[E0308]: mismatched types - --> $DIR/assoc-ty.rs:15:36 +error[E0271]: type mismatch resolving `<() as Trait>::Output normalizes-to _` + --> $DIR/assoc-ty.rs:15:12 | LL | let _: <() as Trait>::Output = (); - | --------------------- ^^ types differ - | | - | expected due to this + | ^^^^^^^^^^^^^^^^^^^^^ types differ + +error[E0271]: type mismatch resolving `<() as Trait>::Output normalizes-to _` + --> $DIR/assoc-ty.rs:15:12 + | +LL | let _: <() as Trait>::Output = (); + | ^^^^^^^^^^^^^^^^^^^^^ types differ | - = note: expected associated type `<() as Trait>::Output` - found unit type `()` - = help: consider constraining the associated type `<() as Trait>::Output` to `()` or calling a method that returns `<() as Trait>::Output` - = note: for more information, visit https://doc.rust-lang.org/book/ch19-03-advanced-traits.html + = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no` -error: aborting due to 3 previous errors +error: aborting due to 4 previous errors -Some errors have detailed explanations: E0308, E0380, E0658. -For more information about an error, try `rustc --explain E0308`. +Some errors have detailed explanations: E0271, E0380, E0658. +For more information about an error, try `rustc --explain E0271`. diff --git a/tests/ui/auto-traits/assoc-ty.rs b/tests/ui/auto-traits/assoc-ty.rs index ada75147f6e..efbfead9cd0 100644 --- a/tests/ui/auto-traits/assoc-ty.rs +++ b/tests/ui/auto-traits/assoc-ty.rs @@ -13,5 +13,7 @@ auto trait Trait { fn main() { let _: <() as Trait>::Output = (); - //~^ ERROR mismatched types + //[current]~^ ERROR mismatched types + //[next]~^^ ERROR type mismatch resolving `<() as Trait>::Output normalizes-to _` + //[next]~| ERROR type mismatch resolving `<() as Trait>::Output normalizes-to _` } diff --git a/tests/ui/impl-trait/ice-unexpected-param-type-whensubstituting-in-region-112823.next.stderr b/tests/ui/impl-trait/ice-unexpected-param-type-whensubstituting-in-region-112823.next.stderr index 3c24eb9adbe..ce64a022214 100644 --- a/tests/ui/impl-trait/ice-unexpected-param-type-whensubstituting-in-region-112823.next.stderr +++ b/tests/ui/impl-trait/ice-unexpected-param-type-whensubstituting-in-region-112823.next.stderr @@ -23,7 +23,19 @@ error[E0271]: type mismatch resolving `<Y as X>::LineStreamFut<'a, Repr> == ()` LL | fn line_stream<'a, Repr>(&'a self) -> Self::LineStreamFut<'a, Repr> {} | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ types differ -error: aborting due to 3 previous errors +error[E0271]: type mismatch resolving `<Y as X>::LineStreamFut<'a, Repr> normalizes-to _` + --> $DIR/ice-unexpected-param-type-whensubstituting-in-region-112823.rs:28:73 + | +LL | fn line_stream<'a, Repr>(&'a self) -> Self::LineStreamFut<'a, Repr> {} + | ^^ types differ + +error[E0271]: type mismatch resolving `<Y as X>::LineStreamFut<'a, Repr> normalizes-to _` + --> $DIR/ice-unexpected-param-type-whensubstituting-in-region-112823.rs:28:5 + | +LL | fn line_stream<'a, Repr>(&'a self) -> Self::LineStreamFut<'a, Repr> {} + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ types differ + +error: aborting due to 5 previous errors Some errors have detailed explanations: E0049, E0271, E0407. For more information about an error, try `rustc --explain E0049`. diff --git a/tests/ui/impl-trait/ice-unexpected-param-type-whensubstituting-in-region-112823.rs b/tests/ui/impl-trait/ice-unexpected-param-type-whensubstituting-in-region-112823.rs index c97bd179943..cb32723b22d 100644 --- a/tests/ui/impl-trait/ice-unexpected-param-type-whensubstituting-in-region-112823.rs +++ b/tests/ui/impl-trait/ice-unexpected-param-type-whensubstituting-in-region-112823.rs @@ -26,9 +26,11 @@ impl X for Y { //~^ ERROR type `LineStream` has 0 type parameters but its trait declaration has 1 type parameter type LineStreamFut<'a, Repr> = impl Future<Output = Self::LineStream<'a, Repr>>; fn line_stream<'a, Repr>(&'a self) -> Self::LineStreamFut<'a, Repr> {} - //[current]~^ ERROR `()` is not a future - //[next]~^^ ERROR type mismatch resolving `<Y as X>::LineStreamFut<'a, Repr> == ()` - //~^^^ method `line_stream` is not a member of trait `X` + //~^ method `line_stream` is not a member of trait `X` + //[current]~^^ ERROR `()` is not a future + //[next]~^^^ ERROR type mismatch resolving `<Y as X>::LineStreamFut<'a, Repr> == ()` + //[next]~| ERROR type mismatch resolving `<Y as X>::LineStreamFut<'a, Repr> normalizes-to _` + //[next]~| ERROR type mismatch resolving `<Y as X>::LineStreamFut<'a, Repr> normalizes-to _` } pub fn main() {} diff --git a/tests/ui/specialization/fuzzed/fuzzing-ice-134905.rs b/tests/ui/specialization/fuzzed/fuzzing-ice-134905.rs new file mode 100644 index 00000000000..559c2345527 --- /dev/null +++ b/tests/ui/specialization/fuzzed/fuzzing-ice-134905.rs @@ -0,0 +1,22 @@ +// This test previously tried to use a tainted `EvalCtxt` when emitting +// an error during coherence. +#![feature(specialization)] +//~^ WARN the feature `specialization` is incomplete +trait Iterate<'a> { + type Ty: Valid; +} +impl<'a, T> Iterate<'a> for T +where + T: Check, +{ + default type Ty = (); + //~^ ERROR the trait bound `(): Valid` is not satisfied +} + +trait Check {} +impl<'a, T> Eq for T where <T as Iterate<'a>>::Ty: Valid {} +//~^ ERROR type parameter `T` must be used as the type parameter for some local type + +trait Valid {} + +fn main() {} diff --git a/tests/ui/specialization/fuzzed/fuzzing-ice-134905.stderr b/tests/ui/specialization/fuzzed/fuzzing-ice-134905.stderr new file mode 100644 index 00000000000..611fef1df66 --- /dev/null +++ b/tests/ui/specialization/fuzzed/fuzzing-ice-134905.stderr @@ -0,0 +1,40 @@ +warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes + --> $DIR/fuzzing-ice-134905.rs:3:12 + | +LL | #![feature(specialization)] + | ^^^^^^^^^^^^^^ + | + = note: see issue #31844 <https://github.com/rust-lang/rust/issues/31844> for more information + = help: consider using `min_specialization` instead, which is more stable and complete + = note: `#[warn(incomplete_features)]` on by default + +error[E0277]: the trait bound `(): Valid` is not satisfied + --> $DIR/fuzzing-ice-134905.rs:12:23 + | +LL | default type Ty = (); + | ^^ the trait `Valid` is not implemented for `()` + | +help: this trait has no implementations, consider adding one + --> $DIR/fuzzing-ice-134905.rs:20:1 + | +LL | trait Valid {} + | ^^^^^^^^^^^ +note: required by a bound in `Iterate::Ty` + --> $DIR/fuzzing-ice-134905.rs:6:14 + | +LL | type Ty: Valid; + | ^^^^^ required by this bound in `Iterate::Ty` + +error[E0210]: type parameter `T` must be used as the type parameter for some local type (e.g., `MyStruct<T>`) + --> $DIR/fuzzing-ice-134905.rs:17:10 + | +LL | impl<'a, T> Eq for T where <T as Iterate<'a>>::Ty: Valid {} + | ^ type parameter `T` must be used as the type parameter for some local type + | + = note: implementing a foreign trait is only possible if at least one of the types for which it is implemented is local + = note: only traits defined in the current crate can be implemented for a type parameter + +error: aborting due to 2 previous errors; 1 warning emitted + +Some errors have detailed explanations: E0210, E0277. +For more information about an error, try `rustc --explain E0210`. |