diff options
Diffstat (limited to 'compiler/rustc_trait_selection')
51 files changed, 3314 insertions, 1722 deletions
diff --git a/compiler/rustc_trait_selection/Cargo.toml b/compiler/rustc_trait_selection/Cargo.toml index d3eba43b4..83605627d 100644 --- a/compiler/rustc_trait_selection/Cargo.toml +++ b/compiler/rustc_trait_selection/Cargo.toml @@ -14,6 +14,7 @@ rustc_ast = { path = "../rustc_ast" } rustc_data_structures = { path = "../rustc_data_structures" } rustc_errors = { path = "../rustc_errors" } rustc_hir = { path = "../rustc_hir" } +rustc_fluent_macro = { path = "../rustc_fluent_macro" } rustc_index = { path = "../rustc_index" } rustc_infer = { path = "../rustc_infer" } rustc_macros = { path = "../rustc_macros" } @@ -24,4 +25,3 @@ rustc_span = { path = "../rustc_span" } rustc_target = { path = "../rustc_target" } rustc_transmute = { path = "../rustc_transmute", features = ["rustc"] } smallvec = { version = "1.8.1", features = ["union", "may_dangle"] } -itertools = "0.10.1" diff --git a/compiler/rustc_trait_selection/messages.ftl b/compiler/rustc_trait_selection/messages.ftl index 14eb4a550..217ba71b6 100644 --- a/compiler/rustc_trait_selection/messages.ftl +++ b/compiler/rustc_trait_selection/messages.ftl @@ -1,17 +1,13 @@ trait_selection_dump_vtable_entries = vtable entries for `{$trait_ref}`: {$entries} -trait_selection_unable_to_construct_constant_value = unable to construct a constant value for the unevaluated constant {$unevaluated} - trait_selection_empty_on_clause_in_rustc_on_unimplemented = empty `on`-clause in `#[rustc_on_unimplemented]` .label = empty on-clause here +trait_selection_inherent_projection_normalization_overflow = overflow evaluating associated type `{$ty}` + trait_selection_invalid_on_clause_in_rustc_on_unimplemented = invalid `on`-clause in `#[rustc_on_unimplemented]` .label = invalid on-clause here -trait_selection_no_value_in_rustc_on_unimplemented = this attribute must have a valid value - .label = expected value here - .note = eg `#[rustc_on_unimplemented(message="foo")]` - trait_selection_negative_positive_conflict = found both positive and negative implementation of trait `{$trait_desc}`{$self_desc -> [none] {""} *[default] {" "}for type `{$self_desc}` @@ -20,3 +16,9 @@ trait_selection_negative_positive_conflict = found both positive and negative im .negative_implementation_in_crate = negative implementation in crate `{$negative_impl_cname}` .positive_implementation_here = positive implementation here .positive_implementation_in_crate = positive implementation in crate `{$positive_impl_cname}` + +trait_selection_no_value_in_rustc_on_unimplemented = this attribute must have a valid value + .label = expected value here + .note = eg `#[rustc_on_unimplemented(message="foo")]` + +trait_selection_unable_to_construct_constant_value = unable to construct a constant value for the unevaluated constant {$unevaluated} diff --git a/compiler/rustc_trait_selection/src/errors.rs b/compiler/rustc_trait_selection/src/errors.rs index df7c4df18..54e22cc3d 100644 --- a/compiler/rustc_trait_selection/src/errors.rs +++ b/compiler/rustc_trait_selection/src/errors.rs @@ -89,3 +89,11 @@ impl IntoDiagnostic<'_> for NegativePositiveConflict<'_> { diag } } + +#[derive(Diagnostic)] +#[diag(trait_selection_inherent_projection_normalization_overflow)] +pub struct InherentProjectionNormalizationOverflow { + #[primary_span] + pub span: Span, + pub ty: String, +} diff --git a/compiler/rustc_trait_selection/src/infer.rs b/compiler/rustc_trait_selection/src/infer.rs index 911cc0b88..312bd3817 100644 --- a/compiler/rustc_trait_selection/src/infer.rs +++ b/compiler/rustc_trait_selection/src/infer.rs @@ -5,7 +5,7 @@ use rustc_hir::def_id::DefId; use rustc_hir::lang_items::LangItem; use rustc_middle::arena::ArenaAllocatable; use rustc_middle::infer::canonical::{Canonical, CanonicalQueryResponse, QueryResponse}; -use rustc_middle::traits::query::Fallible; +use rustc_middle::traits::query::NoSolution; use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable, TypeVisitableExt}; use rustc_middle::ty::{GenericArg, ToPredicate}; use rustc_span::DUMMY_SP; @@ -41,7 +41,7 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> { fn type_is_copy_modulo_regions(&self, param_env: ty::ParamEnv<'tcx>, ty: Ty<'tcx>) -> bool { let ty = self.resolve_vars_if_possible(ty); - if !(param_env, ty).needs_infer() { + if !(param_env, ty).has_infer() { return ty.is_copy_modulo_regions(self.tcx, param_env); } @@ -66,7 +66,7 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> { params: impl IntoIterator<Item: Into<GenericArg<'tcx>>>, param_env: ty::ParamEnv<'tcx>, ) -> traits::EvaluationResult { - let trait_ref = self.tcx.mk_trait_ref(trait_def_id, params); + let trait_ref = ty::TraitRef::new(self.tcx, trait_def_id, params); let obligation = traits::Obligation { cause: traits::ObligationCause::dummy(), @@ -82,8 +82,8 @@ pub trait InferCtxtBuilderExt<'tcx> { fn enter_canonical_trait_query<K, R>( &mut self, canonical_key: &Canonical<'tcx, K>, - operation: impl FnOnce(&ObligationCtxt<'_, 'tcx>, K) -> Fallible<R>, - ) -> Fallible<CanonicalQueryResponse<'tcx, R>> + operation: impl FnOnce(&ObligationCtxt<'_, 'tcx>, K) -> Result<R, NoSolution>, + ) -> Result<CanonicalQueryResponse<'tcx, R>, NoSolution> where K: TypeFoldable<TyCtxt<'tcx>>, R: Debug + TypeFoldable<TyCtxt<'tcx>>, @@ -110,8 +110,8 @@ impl<'tcx> InferCtxtBuilderExt<'tcx> for InferCtxtBuilder<'tcx> { fn enter_canonical_trait_query<K, R>( &mut self, canonical_key: &Canonical<'tcx, K>, - operation: impl FnOnce(&ObligationCtxt<'_, 'tcx>, K) -> Fallible<R>, - ) -> Fallible<CanonicalQueryResponse<'tcx, R>> + operation: impl FnOnce(&ObligationCtxt<'_, 'tcx>, K) -> Result<R, NoSolution>, + ) -> Result<CanonicalQueryResponse<'tcx, R>, NoSolution> where K: TypeFoldable<TyCtxt<'tcx>>, R: Debug + TypeFoldable<TyCtxt<'tcx>>, diff --git a/compiler/rustc_trait_selection/src/lib.rs b/compiler/rustc_trait_selection/src/lib.rs index f866cb016..ed3994be9 100644 --- a/compiler/rustc_trait_selection/src/lib.rs +++ b/compiler/rustc_trait_selection/src/lib.rs @@ -37,7 +37,7 @@ extern crate rustc_middle; extern crate smallvec; use rustc_errors::{DiagnosticMessage, SubdiagnosticMessage}; -use rustc_macros::fluent_messages; +use rustc_fluent_macro::fluent_messages; pub mod errors; pub mod infer; diff --git a/compiler/rustc_trait_selection/src/solve/assembly/mod.rs b/compiler/rustc_trait_selection/src/solve/assembly/mod.rs index 10d817f75..f32ff0442 100644 --- a/compiler/rustc_trait_selection/src/solve/assembly/mod.rs +++ b/compiler/rustc_trait_selection/src/solve/assembly/mod.rs @@ -2,12 +2,12 @@ use super::search_graph::OverflowHandler; use super::{EvalCtxt, SolverMode}; -use crate::solve::CanonicalResponseExt; use crate::traits::coherence; use rustc_data_structures::fx::FxIndexSet; use rustc_hir::def_id::DefId; use rustc_infer::traits::query::NoSolution; use rustc_infer::traits::util::elaborate; +use rustc_infer::traits::Reveal; use rustc_middle::traits::solve::{CanonicalResponse, Certainty, Goal, MaybeCause, QueryResult}; use rustc_middle::ty::fast_reject::TreatProjections; use rustc_middle::ty::TypeFoldable; @@ -51,7 +51,7 @@ pub(super) enum CandidateSource { BuiltinImpl, /// An assumption from the environment. /// - /// More precicely we've used the `n-th` assumption in the `param_env`. + /// More precisely we've used the `n-th` assumption in the `param_env`. /// /// ## Examples /// @@ -87,7 +87,9 @@ pub(super) enum CandidateSource { } /// Methods used to assemble candidates for either trait or projection goals. -pub(super) trait GoalKind<'tcx>: TypeFoldable<TyCtxt<'tcx>> + Copy + Eq { +pub(super) trait GoalKind<'tcx>: + TypeFoldable<TyCtxt<'tcx>> + Copy + Eq + std::fmt::Display +{ fn self_ty(self) -> Ty<'tcx>; fn trait_ref(self, tcx: TyCtxt<'tcx>) -> ty::TraitRef<'tcx>; @@ -96,6 +98,17 @@ pub(super) trait GoalKind<'tcx>: TypeFoldable<TyCtxt<'tcx>> + Copy + Eq { fn trait_def_id(self, tcx: TyCtxt<'tcx>) -> DefId; + // Try equating an assumption predicate against a goal's predicate. If it + // holds, then execute the `then` callback, which should do any additional + // work, then produce a response (typically by executing + // [`EvalCtxt::evaluate_added_goals_and_make_canonical_response`]). + fn probe_and_match_goal_against_assumption( + ecx: &mut EvalCtxt<'_, 'tcx>, + goal: Goal<'tcx, Self>, + assumption: ty::Predicate<'tcx>, + then: impl FnOnce(&mut EvalCtxt<'_, 'tcx>) -> QueryResult<'tcx>, + ) -> QueryResult<'tcx>; + // Consider a clause, which consists of a "assumption" and some "requirements", // to satisfy a goal. If the requirements hold, then attempt to satisfy our // goal by equating it with the assumption. @@ -104,7 +117,26 @@ pub(super) trait GoalKind<'tcx>: TypeFoldable<TyCtxt<'tcx>> + Copy + Eq { goal: Goal<'tcx, Self>, assumption: ty::Predicate<'tcx>, requirements: impl IntoIterator<Item = Goal<'tcx, ty::Predicate<'tcx>>>, - ) -> QueryResult<'tcx>; + ) -> QueryResult<'tcx> { + Self::probe_and_match_goal_against_assumption(ecx, goal, assumption, |ecx| { + ecx.add_goals(requirements); + ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + }) + } + + /// Consider a bound originating from the item bounds of an alias. For this we + /// require that the well-formed requirements of the self type of the goal + /// are "satisfied from the param-env". + /// See [`EvalCtxt::validate_alias_bound_self_from_param_env`]. + fn consider_alias_bound_candidate( + ecx: &mut EvalCtxt<'_, 'tcx>, + goal: Goal<'tcx, Self>, + assumption: ty::Predicate<'tcx>, + ) -> QueryResult<'tcx> { + Self::probe_and_match_goal_against_assumption(ecx, goal, assumption, |ecx| { + ecx.validate_alias_bound_self_from_param_env(goal) + }) + } // Consider a clause specifically for a `dyn Trait` self type. This requires // additionally checking all of the supertraits and object bounds to hold, @@ -113,7 +145,25 @@ pub(super) trait GoalKind<'tcx>: TypeFoldable<TyCtxt<'tcx>> + Copy + Eq { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, assumption: ty::Predicate<'tcx>, - ) -> QueryResult<'tcx>; + ) -> QueryResult<'tcx> { + Self::probe_and_match_goal_against_assumption(ecx, goal, assumption, |ecx| { + let tcx = ecx.tcx(); + let ty::Dynamic(bounds, _, _) = *goal.predicate.self_ty().kind() else { + bug!("expected object type in `consider_object_bound_candidate`"); + }; + ecx.add_goals( + structural_traits::predicates_for_object_candidate( + &ecx, + goal.param_env, + goal.predicate.trait_ref(tcx), + bounds, + ) + .into_iter() + .map(|pred| goal.with(tcx, pred)), + ); + ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + }) + } fn consider_impl_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, @@ -241,7 +291,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { // HACK: `_: Trait` is ambiguous, because it may be satisfied via a builtin rule, // object bound, alias bound, etc. We are unable to determine this until we can at - // least structually resolve the type one layer. + // least structurally resolve the type one layer. if goal.predicate.self_ty().is_ty_var() { return vec![Candidate { source: CandidateSource::BuiltinImpl, @@ -282,8 +332,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { candidates: &mut Vec<Candidate<'tcx>>, ) { let tcx = self.tcx(); - // FIXME: We also have to normalize opaque types, not sure where to best fit that in. - let &ty::Alias(ty::Projection, projection_ty) = goal.predicate.self_ty().kind() else { + let &ty::Alias(_, projection_ty) = goal.predicate.self_ty().kind() else { return }; @@ -305,8 +354,11 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { }), ); ecx.add_goal(normalizes_to_goal); - let _ = ecx.try_evaluate_added_goals()?; + let _ = ecx.try_evaluate_added_goals().inspect_err(|_| { + debug!("self type normalization failed"); + })?; let normalized_ty = ecx.resolve_vars_if_possible(normalized_ty); + debug!(?normalized_ty, "self type normalized"); // NOTE: Alternatively we could call `evaluate_goal` here and only // have a `Normalized` candidate. This doesn't work as long as we // use `CandidateSource` in winnowing. @@ -455,15 +507,17 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { | ty::Param(_) | ty::Placeholder(..) | ty::Infer(ty::IntVar(_) | ty::FloatVar(_)) + | ty::Alias(ty::Inherent, _) | ty::Error(_) => return, ty::Infer(ty::TyVar(_) | ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_)) | ty::Bound(..) => bug!("unexpected self type for `{goal:?}`"), - ty::Alias(_, alias_ty) => alias_ty, + // Excluding IATs here as they don't have meaningful item bounds. + ty::Alias(ty::Projection | ty::Opaque, alias_ty) => alias_ty, }; for assumption in self.tcx().item_bounds(alias_ty.def_id).subst(self.tcx(), alias_ty.substs) { - match G::consider_implied_clause(self, goal, assumption, []) { + match G::consider_alias_bound_candidate(self, goal, assumption) { Ok(result) => { candidates.push(Candidate { source: CandidateSource::AliasBound, result }) } @@ -472,6 +526,105 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { } } + /// Check that we are allowed to use an alias bound originating from the self + /// type of this goal. This means something different depending on the self type's + /// alias kind. + /// + /// * Projection: Given a goal with a self type such as `<Ty as Trait>::Assoc`, + /// we require that the bound `Ty: Trait` can be proven using either a nested alias + /// bound candidate, or a param-env candidate. + /// + /// * Opaque: The param-env must be in `Reveal::UserFacing` mode. Otherwise, + /// the goal should be proven by using the hidden type instead. + #[instrument(level = "debug", skip(self), ret)] + pub(super) fn validate_alias_bound_self_from_param_env<G: GoalKind<'tcx>>( + &mut self, + goal: Goal<'tcx, G>, + ) -> QueryResult<'tcx> { + match *goal.predicate.self_ty().kind() { + ty::Alias(ty::Projection, projection_ty) => { + let mut param_env_candidates = vec![]; + let self_trait_ref = projection_ty.trait_ref(self.tcx()); + + if self_trait_ref.self_ty().is_ty_var() { + return self + .evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS); + } + + let trait_goal: Goal<'_, ty::TraitPredicate<'tcx>> = goal.with( + self.tcx(), + ty::TraitPredicate { + trait_ref: self_trait_ref, + constness: ty::BoundConstness::NotConst, + polarity: ty::ImplPolarity::Positive, + }, + ); + + self.assemble_param_env_candidates(trait_goal, &mut param_env_candidates); + // FIXME: We probably need some sort of recursion depth check here. + // Can't come up with an example yet, though, and the worst case + // we can have is a compiler stack overflow... + self.assemble_alias_bound_candidates(trait_goal, &mut param_env_candidates); + + // FIXME: We must also consider alias-bound candidates for a peculiar + // class of built-in candidates that I'll call "defaulted" built-ins. + // + // For example, we always know that `T: Pointee` is implemented, but + // we do not always know what `<T as Pointee>::Metadata` actually is, + // similar to if we had a user-defined impl with a `default type ...`. + // For these traits, since we're not able to always normalize their + // associated types to a concrete type, we must consider their alias bounds + // instead, so we can prove bounds such as `<T as Pointee>::Metadata: Copy`. + self.assemble_alias_bound_candidates_for_builtin_impl_default_items( + trait_goal, + &mut param_env_candidates, + ); + + self.merge_candidates(param_env_candidates) + } + ty::Alias(ty::Opaque, _opaque_ty) => match goal.param_env.reveal() { + Reveal::UserFacing => { + self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + } + Reveal::All => return Err(NoSolution), + }, + _ => bug!("only expected to be called on alias tys"), + } + } + + /// Assemble a subset of builtin impl candidates for a class of candidates called + /// "defaulted" built-in traits. + /// + /// For example, we always know that `T: Pointee` is implemented, but we do not + /// always know what `<T as Pointee>::Metadata` actually is! See the comment in + /// [`EvalCtxt::validate_alias_bound_self_from_param_env`] for more detail. + #[instrument(level = "debug", skip_all)] + fn assemble_alias_bound_candidates_for_builtin_impl_default_items<G: GoalKind<'tcx>>( + &mut self, + goal: Goal<'tcx, G>, + candidates: &mut Vec<Candidate<'tcx>>, + ) { + let lang_items = self.tcx().lang_items(); + let trait_def_id = goal.predicate.trait_def_id(self.tcx()); + + // You probably shouldn't add anything to this list unless you + // know what you're doing. + let result = if lang_items.pointee_trait() == Some(trait_def_id) { + G::consider_builtin_pointee_candidate(self, goal) + } else if lang_items.discriminant_kind_trait() == Some(trait_def_id) { + G::consider_builtin_discriminant_kind_candidate(self, goal) + } else { + Err(NoSolution) + }; + + match result { + Ok(result) => { + candidates.push(Candidate { source: CandidateSource::BuiltinImpl, result }) + } + Err(NoSolution) => (), + } + } + #[instrument(level = "debug", skip_all)] fn assemble_object_bound_candidates<G: GoalKind<'tcx>>( &mut self, @@ -590,13 +743,18 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { SolverMode::Normal => { let param_env_responses = candidates .iter() - .filter(|c| matches!(c.source, CandidateSource::ParamEnv(_))) + .filter(|c| { + matches!( + c.source, + CandidateSource::ParamEnv(_) | CandidateSource::AliasBound + ) + }) .map(|c| c.result) .collect::<Vec<_>>(); if let Some(result) = self.try_merge_responses(¶m_env_responses) { - if result.has_only_region_constraints() { - return Ok(result); - } + // We strongly prefer alias and param-env bounds here, even if they affect inference. + // See https://github.com/rust-lang/trait-system-refactor-initiative/issues/11. + return Ok(result); } } } diff --git a/compiler/rustc_trait_selection/src/solve/assembly/structural_traits.rs b/compiler/rustc_trait_selection/src/solve/assembly/structural_traits.rs index 1a566e87d..0ede32c75 100644 --- a/compiler/rustc_trait_selection/src/solve/assembly/structural_traits.rs +++ b/compiler/rustc_trait_selection/src/solve/assembly/structural_traits.rs @@ -33,7 +33,7 @@ pub(in crate::solve) fn instantiate_constituent_tys_for_auto_trait<'tcx>( ty::Dynamic(..) | ty::Param(..) | ty::Foreign(..) - | ty::Alias(ty::Projection, ..) + | ty::Alias(ty::Projection | ty::Inherent, ..) | ty::Placeholder(..) | ty::Bound(..) | ty::Infer(_) => { @@ -91,14 +91,15 @@ pub(in crate::solve) fn replace_erased_lifetimes_with_bound_vars<'tcx>( ) -> ty::Binder<'tcx, Ty<'tcx>> { debug_assert!(!ty.has_late_bound_regions()); let mut counter = 0; - let ty = tcx.fold_regions(ty, |mut r, current_depth| { - if let ty::ReErased = r.kind() { + let ty = tcx.fold_regions(ty, |r, current_depth| match r.kind() { + ty::ReErased => { let br = ty::BoundRegion { var: ty::BoundVar::from_u32(counter), kind: ty::BrAnon(None) }; counter += 1; - r = tcx.mk_re_late_bound(current_depth, br); + tcx.mk_re_late_bound(current_depth, br) } - r + // All free regions should be erased here. + r => bug!("unexpected region: {r:?}"), }); let bound_vars = tcx.mk_bound_variable_kinds_from_iter( (0..counter).map(|_| ty::BoundVariableKind::Region(ty::BrAnon(None))), diff --git a/compiler/rustc_trait_selection/src/solve/canonicalize.rs b/compiler/rustc_trait_selection/src/solve/canonicalize.rs index 976849696..ff4bff10c 100644 --- a/compiler/rustc_trait_selection/src/solve/canonicalize.rs +++ b/compiler/rustc_trait_selection/src/solve/canonicalize.rs @@ -69,7 +69,7 @@ impl<'a, 'tcx> Canonicalizer<'a, 'tcx> { }; let value = value.fold_with(&mut canonicalizer); - assert!(!value.needs_infer()); + assert!(!value.has_infer()); assert!(!value.has_placeholders()); let (max_universe, variables) = canonicalizer.finalize(); diff --git a/compiler/rustc_trait_selection/src/solve/eval_ctxt.rs b/compiler/rustc_trait_selection/src/solve/eval_ctxt.rs index c29b5b04e..f91c67277 100644 --- a/compiler/rustc_trait_selection/src/solve/eval_ctxt.rs +++ b/compiler/rustc_trait_selection/src/solve/eval_ctxt.rs @@ -1,14 +1,19 @@ -use rustc_hir::def_id::DefId; +use rustc_hir::def_id::{DefId, LocalDefId}; use rustc_infer::infer::at::ToTrace; use rustc_infer::infer::canonical::CanonicalVarValues; use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind}; use rustc_infer::infer::{ - DefineOpaqueTypes, InferCtxt, InferOk, LateBoundRegionConversionTime, TyCtxtInferExt, + DefineOpaqueTypes, InferCtxt, InferOk, LateBoundRegionConversionTime, RegionVariableOrigin, + TyCtxtInferExt, }; use rustc_infer::traits::query::NoSolution; use rustc_infer::traits::ObligationCause; use rustc_middle::infer::unify_key::{ConstVariableOrigin, ConstVariableOriginKind}; -use rustc_middle::traits::solve::{CanonicalGoal, Certainty, MaybeCause, QueryResult}; +use rustc_middle::traits::solve::{ + CanonicalInput, CanonicalResponse, Certainty, MaybeCause, PredefinedOpaques, + PredefinedOpaquesData, QueryResult, +}; +use rustc_middle::traits::DefiningAnchor; use rustc_middle::ty::{ self, Ty, TyCtxt, TypeFoldable, TypeSuperVisitable, TypeVisitable, TypeVisitableExt, TypeVisitor, @@ -43,6 +48,9 @@ pub struct EvalCtxt<'a, 'tcx> { infcx: &'a InferCtxt<'tcx>, pub(super) var_values: CanonicalVarValues<'tcx>, + + predefined_opaques_in_body: PredefinedOpaques<'tcx>, + /// The highest universe index nameable by the caller. /// /// When we enter a new binder inside of the query we create new universes @@ -57,6 +65,14 @@ pub struct EvalCtxt<'a, 'tcx> { pub(super) search_graph: &'a mut SearchGraph<'tcx>, pub(super) nested_goals: NestedGoals<'tcx>, + + // Has this `EvalCtxt` errored out with `NoSolution` in `try_evaluate_added_goals`? + // + // If so, then it can no longer be used to make a canonical query response, + // since subsequent calls to `try_evaluate_added_goals` have possibly dropped + // ambiguous goals. Instead, a probe needs to be introduced somewhere in the + // evaluation code. + tainted: Result<(), NoSolution>, } #[derive(Debug, Copy, Clone, PartialEq, Eq)] @@ -117,10 +133,16 @@ impl<'tcx> InferCtxtEvalExt<'tcx> for InferCtxt<'tcx> { let mut ecx = EvalCtxt { search_graph: &mut search_graph, infcx: self, + // Only relevant when canonicalizing the response, + // which we don't do within this evaluation context. + predefined_opaques_in_body: self + .tcx + .mk_predefined_opaques_in_body(PredefinedOpaquesData::default()), // Only relevant when canonicalizing the response. max_input_universe: ty::UniverseIndex::ROOT, var_values: CanonicalVarValues::dummy(), nested_goals: NestedGoals::new(), + tainted: Ok(()), }; let result = ecx.evaluate_goal(IsNormalizesToHack::No, goal); @@ -152,28 +174,53 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> { fn evaluate_canonical_goal( tcx: TyCtxt<'tcx>, search_graph: &'a mut search_graph::SearchGraph<'tcx>, - canonical_goal: CanonicalGoal<'tcx>, + canonical_input: CanonicalInput<'tcx>, ) -> QueryResult<'tcx> { // Deal with overflow, caching, and coinduction. // // The actual solver logic happens in `ecx.compute_goal`. - search_graph.with_new_goal(tcx, canonical_goal, |search_graph| { + search_graph.with_new_goal(tcx, canonical_input, |search_graph| { let intercrate = match search_graph.solver_mode() { SolverMode::Normal => false, SolverMode::Coherence => true, }; - let (ref infcx, goal, var_values) = tcx + let (ref infcx, input, var_values) = tcx .infer_ctxt() .intercrate(intercrate) - .build_with_canonical(DUMMY_SP, &canonical_goal); + .with_opaque_type_inference(canonical_input.value.anchor) + .build_with_canonical(DUMMY_SP, &canonical_input); + + for &(a, b) in &input.predefined_opaques_in_body.opaque_types { + let InferOk { value: (), obligations } = infcx + .register_hidden_type_in_new_solver(a, input.goal.param_env, b) + .expect("expected opaque type instantiation to succeed"); + // We're only registering opaques already defined by the caller, + // so we're not responsible for proving that they satisfy their + // item bounds, unless we use them in a normalizes-to goal, + // which is handled in `EvalCtxt::unify_existing_opaque_tys`. + let _ = obligations; + } let mut ecx = EvalCtxt { infcx, var_values, - max_input_universe: canonical_goal.max_universe, + predefined_opaques_in_body: input.predefined_opaques_in_body, + max_input_universe: canonical_input.max_universe, search_graph, nested_goals: NestedGoals::new(), + tainted: Ok(()), }; - ecx.compute_goal(goal) + + let result = ecx.compute_goal(input.goal); + + // When creating a query response we clone the opaque type constraints + // instead of taking them. This would cause an ICE here, since we have + // assertions against dropping an `InferCtxt` without taking opaques. + // FIXME: Once we remove support for the old impl we can remove this. + if input.anchor != DefiningAnchor::Error { + let _ = infcx.take_opaque_types(); + } + + result }) } @@ -188,7 +235,8 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> { let canonical_response = EvalCtxt::evaluate_canonical_goal(self.tcx(), self.search_graph, canonical_goal)?; - let has_changed = !canonical_response.value.var_values.is_identity(); + let has_changed = !canonical_response.value.var_values.is_identity() + || !canonical_response.value.external_constraints.opaque_types.is_empty(); let (certainty, nested_goals) = self.instantiate_and_apply_query_response( goal.param_env, orig_values, @@ -213,18 +261,20 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> { { debug!("rerunning goal to check result is stable"); let (_orig_values, canonical_goal) = self.canonicalize_goal(goal); - let canonical_response = + let new_canonical_response = EvalCtxt::evaluate_canonical_goal(self.tcx(), self.search_graph, canonical_goal)?; - if !canonical_response.value.var_values.is_identity() { + if !new_canonical_response.value.var_values.is_identity() { bug!( "unstable result: re-canonicalized goal={canonical_goal:#?} \ - response={canonical_response:#?}" + first_response={canonical_response:#?} \ + second_response={new_canonical_response:#?}" ); } - if certainty != canonical_response.value.certainty { + if certainty != new_canonical_response.value.certainty { bug!( "unstable certainty: {certainty:#?} re-canonicalized goal={canonical_goal:#?} \ - response={canonical_response:#?}" + first_response={canonical_response:#?} \ + second_response={new_canonical_response:#?}" ); } } @@ -391,6 +441,10 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> { }, ); + if response.is_err() { + self.tainted = Err(NoSolution); + } + self.nested_goals = goals; response } @@ -401,9 +455,11 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { let mut ecx = EvalCtxt { infcx: self.infcx, var_values: self.var_values, + predefined_opaques_in_body: self.predefined_opaques_in_body, max_input_universe: self.max_input_universe, search_graph: self.search_graph, nested_goals: self.nested_goals.clone(), + tainted: self.tainted, }; self.infcx.probe(|_| f(&mut ecx)) } @@ -419,6 +475,10 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { }) } + pub(super) fn next_region_infer(&self) -> ty::Region<'tcx> { + self.infcx.next_region_var(RegionVariableOrigin::MiscVariable(DUMMY_SP)) + } + pub(super) fn next_const_infer(&self, ty: Ty<'tcx>) -> ty::Const<'tcx> { self.infcx.next_const_var( ty, @@ -649,7 +709,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { // FIXME(transmutability): This really should be returning nested goals for `Answer::If*` match rustc_transmute::TransmuteTypeEnv::new(self.infcx).is_transmutable( ObligationCause::dummy(), - ty::Binder::dummy(src_and_dst), + src_and_dst, scope, assume, ) { @@ -660,4 +720,56 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { | rustc_transmute::Answer::IfAny(_) => Err(NoSolution), } } + + pub(super) fn can_define_opaque_ty(&mut self, def_id: LocalDefId) -> bool { + self.infcx.opaque_type_origin(def_id).is_some() + } + + pub(super) fn register_opaque_ty( + &mut self, + a: ty::OpaqueTypeKey<'tcx>, + b: Ty<'tcx>, + param_env: ty::ParamEnv<'tcx>, + ) -> Result<(), NoSolution> { + let InferOk { value: (), obligations } = + self.infcx.register_hidden_type_in_new_solver(a, param_env, b)?; + self.add_goals(obligations.into_iter().map(|obligation| obligation.into())); + Ok(()) + } + + // Do something for each opaque/hidden pair defined with `def_id` in the + // current inference context. + pub(super) fn unify_existing_opaque_tys( + &mut self, + param_env: ty::ParamEnv<'tcx>, + key: ty::OpaqueTypeKey<'tcx>, + ty: Ty<'tcx>, + ) -> Vec<CanonicalResponse<'tcx>> { + // FIXME: Super inefficient to be cloning this... + let opaques = self.infcx.clone_opaque_types_for_query_response(); + + let mut values = vec![]; + for (candidate_key, candidate_ty) in opaques { + if candidate_key.def_id != key.def_id { + continue; + } + values.extend(self.probe(|ecx| { + for (a, b) in std::iter::zip(candidate_key.substs, key.substs) { + ecx.eq(param_env, a, b)?; + } + ecx.eq(param_env, candidate_ty, ty)?; + let mut obl = vec![]; + ecx.infcx.add_item_bounds_for_hidden_type( + candidate_key, + ObligationCause::dummy(), + param_env, + candidate_ty, + &mut obl, + ); + ecx.add_goals(obl.into_iter().map(Into::into)); + ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + })); + } + values + } } diff --git a/compiler/rustc_trait_selection/src/solve/eval_ctxt/canonical.rs b/compiler/rustc_trait_selection/src/solve/eval_ctxt/canonical.rs index ada868705..fdb209fbf 100644 --- a/compiler/rustc_trait_selection/src/solve/eval_ctxt/canonical.rs +++ b/compiler/rustc_trait_selection/src/solve/eval_ctxt/canonical.rs @@ -8,15 +8,19 @@ /// section of the [rustc-dev-guide][c]. /// /// [c]: https://rustc-dev-guide.rust-lang.org/solve/canonicalization.html -use super::{CanonicalGoal, Certainty, EvalCtxt, Goal}; +use super::{CanonicalInput, Certainty, EvalCtxt, Goal}; use crate::solve::canonicalize::{CanonicalizeMode, Canonicalizer}; use crate::solve::{CanonicalResponse, QueryResult, Response}; +use rustc_index::IndexVec; use rustc_infer::infer::canonical::query_response::make_query_region_constraints; use rustc_infer::infer::canonical::CanonicalVarValues; use rustc_infer::infer::canonical::{CanonicalExt, QueryRegionConstraints}; +use rustc_infer::infer::InferOk; use rustc_middle::traits::query::NoSolution; -use rustc_middle::traits::solve::{ExternalConstraints, ExternalConstraintsData}; -use rustc_middle::ty::{self, GenericArgKind}; +use rustc_middle::traits::solve::{ + ExternalConstraints, ExternalConstraintsData, MaybeCause, PredefinedOpaquesData, QueryInput, +}; +use rustc_middle::ty::{self, BoundVar, GenericArgKind, Ty}; use rustc_span::DUMMY_SP; use std::iter; use std::ops::Deref; @@ -27,13 +31,21 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { pub(super) fn canonicalize_goal( &self, goal: Goal<'tcx, ty::Predicate<'tcx>>, - ) -> (Vec<ty::GenericArg<'tcx>>, CanonicalGoal<'tcx>) { + ) -> (Vec<ty::GenericArg<'tcx>>, CanonicalInput<'tcx>) { let mut orig_values = Default::default(); let canonical_goal = Canonicalizer::canonicalize( self.infcx, CanonicalizeMode::Input, &mut orig_values, - goal, + QueryInput { + goal, + anchor: self.infcx.defining_use_anchor, + predefined_opaques_in_body: self.tcx().mk_predefined_opaques_in_body( + PredefinedOpaquesData { + opaque_types: self.infcx.clone_opaque_types_for_query_response(), + }, + ), + }, ); (orig_values, canonical_goal) } @@ -50,11 +62,36 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { certainty: Certainty, ) -> QueryResult<'tcx> { let goals_certainty = self.try_evaluate_added_goals()?; + assert_eq!( + self.tainted, + Ok(()), + "EvalCtxt is tainted -- nested goals may have been dropped in a \ + previous call to `try_evaluate_added_goals!`" + ); + let certainty = certainty.unify_with(goals_certainty); - let external_constraints = self.compute_external_query_constraints()?; + let response = match certainty { + Certainty::Yes | Certainty::Maybe(MaybeCause::Ambiguity) => { + let external_constraints = self.compute_external_query_constraints()?; + Response { var_values: self.var_values, external_constraints, certainty } + } + Certainty::Maybe(MaybeCause::Overflow) => { + // If we have overflow, it's probable that we're substituting a type + // into itself infinitely and any partial substitutions in the query + // response are probably not useful anyways, so just return an empty + // query response. + // + // This may prevent us from potentially useful inference, e.g. + // 2 candidates, one ambiguous and one overflow, which both + // have the same inference constraints. + // + // Changing this to retain some constraints in the future + // won't be a breaking change, so this is good enough for now. + return Ok(self.make_ambiguous_response_no_constraints(MaybeCause::Overflow)); + } + }; - let response = Response { var_values: self.var_values, external_constraints, certainty }; let canonical = Canonicalizer::canonicalize( self.infcx, CanonicalizeMode::Response { max_input_universe: self.max_input_universe }, @@ -64,6 +101,40 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { Ok(canonical) } + /// Constructs a totally unconstrained, ambiguous response to a goal. + /// + /// Take care when using this, since often it's useful to respond with + /// ambiguity but return constrained variables to guide inference. + pub(in crate::solve) fn make_ambiguous_response_no_constraints( + &self, + maybe_cause: MaybeCause, + ) -> CanonicalResponse<'tcx> { + let unconstrained_response = Response { + var_values: CanonicalVarValues { + var_values: self.tcx().mk_substs_from_iter(self.var_values.var_values.iter().map( + |arg| -> ty::GenericArg<'tcx> { + match arg.unpack() { + GenericArgKind::Lifetime(_) => self.next_region_infer().into(), + GenericArgKind::Type(_) => self.next_ty_infer().into(), + GenericArgKind::Const(ct) => self.next_const_infer(ct.ty()).into(), + } + }, + )), + }, + external_constraints: self + .tcx() + .mk_external_constraints(ExternalConstraintsData::default()), + certainty: Certainty::Maybe(maybe_cause), + }; + + Canonicalizer::canonicalize( + self.infcx, + CanonicalizeMode::Response { max_input_universe: self.max_input_universe }, + &mut Default::default(), + unconstrained_response, + ) + } + #[instrument(level = "debug", skip(self), ret)] fn compute_external_query_constraints(&self) -> Result<ExternalConstraints<'tcx>, NoSolution> { // Cannot use `take_registered_region_obligations` as we may compute the response @@ -78,7 +149,13 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { region_constraints, ) }); - let opaque_types = self.infcx.clone_opaque_types_for_query_response(); + + let mut opaque_types = self.infcx.clone_opaque_types_for_query_response(); + // Only return opaque type keys for newly-defined opaques + opaque_types.retain(|(a, _)| { + self.predefined_opaques_in_body.opaque_types.iter().all(|(pa, _)| pa != a) + }); + Ok(self .tcx() .mk_external_constraints(ExternalConstraintsData { region_constraints, opaque_types })) @@ -104,10 +181,10 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { let nested_goals = self.unify_query_var_values(param_env, &original_values, var_values)?; - // FIXME: implement external constraints. - let ExternalConstraintsData { region_constraints, opaque_types: _ } = + let ExternalConstraintsData { region_constraints, opaque_types } = external_constraints.deref(); self.register_region_constraints(region_constraints); + self.register_opaque_types(param_env, opaque_types)?; Ok((certainty, nested_goals)) } @@ -139,25 +216,25 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { // // We therefore instantiate the existential variable in the canonical response with the // inference variable of the input right away, which is more performant. - let mut opt_values = vec![None; response.variables.len()]; + let mut opt_values = IndexVec::from_elem_n(None, response.variables.len()); for (original_value, result_value) in iter::zip(original_values, var_values.var_values) { match result_value.unpack() { GenericArgKind::Type(t) => { if let &ty::Bound(debruijn, b) = t.kind() { assert_eq!(debruijn, ty::INNERMOST); - opt_values[b.var.index()] = Some(*original_value); + opt_values[b.var] = Some(*original_value); } } GenericArgKind::Lifetime(r) => { if let ty::ReLateBound(debruijn, br) = *r { assert_eq!(debruijn, ty::INNERMOST); - opt_values[br.var.index()] = Some(*original_value); + opt_values[br.var] = Some(*original_value); } } GenericArgKind::Const(c) => { - if let ty::ConstKind::Bound(debrujin, b) = c.kind() { - assert_eq!(debrujin, ty::INNERMOST); - opt_values[b.index()] = Some(*original_value); + if let ty::ConstKind::Bound(debruijn, b) = c.kind() { + assert_eq!(debruijn, ty::INNERMOST); + opt_values[b] = Some(*original_value); } } } @@ -176,11 +253,11 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { // As an optimization we sometimes avoid creating a new inference variable here. // // All new inference variables we create start out in the current universe of the caller. - // This is conceptionally wrong as these inference variables would be able to name + // This is conceptually wrong as these inference variables would be able to name // more placeholders then they should be able to. However the inference variables have // to "come from somewhere", so by equating them with the original values of the caller // later on, we pull them down into their correct universe again. - if let Some(v) = opt_values[index] { + if let Some(v) = opt_values[BoundVar::from_usize(index)] { v } else { self.infcx.instantiate_canonical_var(DUMMY_SP, info, |_| prev_universe) @@ -227,4 +304,19 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { let _ = member_constraint; } } + + fn register_opaque_types( + &mut self, + param_env: ty::ParamEnv<'tcx>, + opaque_types: &[(ty::OpaqueTypeKey<'tcx>, Ty<'tcx>)], + ) -> Result<(), NoSolution> { + for &(a, b) in opaque_types { + let InferOk { value: (), obligations } = + self.infcx.register_hidden_type_in_new_solver(a, param_env, b)?; + // It's sound to drop these obligations, since the normalizes-to goal + // is responsible for proving these obligations. + let _ = obligations; + } + Ok(()) + } } diff --git a/compiler/rustc_trait_selection/src/solve/fulfill.rs b/compiler/rustc_trait_selection/src/solve/fulfill.rs index 32bd10f0b..4a403196c 100644 --- a/compiler/rustc_trait_selection/src/solve/fulfill.rs +++ b/compiler/rustc_trait_selection/src/solve/fulfill.rs @@ -133,12 +133,14 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentCtxt<'tcx> { | ty::PredicateKind::ObjectSafe(_) | ty::PredicateKind::ClosureKind(_, _, _) | ty::PredicateKind::ConstEvaluatable(_) - | ty::PredicateKind::TypeWellFormedFromEnv(_) | ty::PredicateKind::Ambiguous => { FulfillmentErrorCode::CodeSelectionError( SelectionError::Unimplemented, ) } + ty::PredicateKind::TypeWellFormedFromEnv(_) => { + bug!("unexpected goal: {goal:?}") + } }, root_obligation: obligation, }); diff --git a/compiler/rustc_trait_selection/src/solve/mod.rs b/compiler/rustc_trait_selection/src/solve/mod.rs index 19bcbd461..56a254d9c 100644 --- a/compiler/rustc_trait_selection/src/solve/mod.rs +++ b/compiler/rustc_trait_selection/src/solve/mod.rs @@ -24,6 +24,7 @@ mod assembly; mod canonicalize; mod eval_ctxt; mod fulfill; +mod opaques; mod project_goals; mod search_graph; mod trait_goals; @@ -212,7 +213,7 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> { ); } - match (lhs.to_projection_term(tcx), rhs.to_projection_term(tcx)) { + match (lhs.to_alias_ty(tcx), rhs.to_alias_ty(tcx)) { (None, None) => bug!("`AliasRelate` goal without an alias on either lhs or rhs"), // RHS is not a projection, only way this is true is if LHS normalizes-to RHS @@ -230,44 +231,60 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> { let mut candidates = Vec::new(); // LHS normalizes-to RHS - candidates.extend( - evaluate_normalizes_to(self, alias_lhs, rhs, direction, Invert::No).ok(), - ); + candidates.extend(evaluate_normalizes_to( + self, + alias_lhs, + rhs, + direction, + Invert::No, + )); // RHS normalizes-to RHS - candidates.extend( - evaluate_normalizes_to(self, alias_rhs, lhs, direction, Invert::Yes).ok(), - ); + candidates.extend(evaluate_normalizes_to( + self, + alias_rhs, + lhs, + direction, + Invert::Yes, + )); // Relate via substs - candidates.extend( - self.probe(|ecx| { - let span = tracing::span!( - tracing::Level::DEBUG, - "compute_alias_relate_goal(relate_via_substs)", - ?alias_lhs, - ?alias_rhs, - ?direction - ); - let _enter = span.enter(); - - match direction { - ty::AliasRelationDirection::Equate => { - ecx.eq(goal.param_env, alias_lhs, alias_rhs)?; - } - ty::AliasRelationDirection::Subtype => { - ecx.sub(goal.param_env, alias_lhs, alias_rhs)?; - } + let subst_relate_response = self.probe(|ecx| { + let span = tracing::span!( + tracing::Level::DEBUG, + "compute_alias_relate_goal(relate_via_substs)", + ?alias_lhs, + ?alias_rhs, + ?direction + ); + let _enter = span.enter(); + + match direction { + ty::AliasRelationDirection::Equate => { + ecx.eq(goal.param_env, alias_lhs, alias_rhs)?; + } + ty::AliasRelationDirection::Subtype => { + ecx.sub(goal.param_env, alias_lhs, alias_rhs)?; } + } - ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) - }) - .ok(), - ); + ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + }); + candidates.extend(subst_relate_response); debug!(?candidates); if let Some(merged) = self.try_merge_responses(&candidates) { Ok(merged) } else { - self.flounder(&candidates) + // When relating two aliases and we have ambiguity, we prefer + // relating the generic arguments of the aliases over normalizing + // them. This is necessary for inference during typeck. + // + // As this is incomplete, we must not do so during coherence. + match (self.solver_mode(), subst_relate_response) { + (SolverMode::Normal, Ok(response)) => Ok(response), + (SolverMode::Normal, Err(NoSolution)) | (SolverMode::Coherence, _) => { + self.flounder(&candidates) + } + } } } } @@ -340,17 +357,17 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { if responses.is_empty() { return Err(NoSolution); } - let certainty = responses.iter().fold(Certainty::AMBIGUOUS, |certainty, response| { - certainty.unify_with(response.value.certainty) - }); - - let response = self.evaluate_added_goals_and_make_canonical_response(certainty); - if let Ok(response) = response { - assert!(response.has_no_inference_or_external_constraints()); - Ok(response) - } else { - bug!("failed to make floundered response: {responses:?}"); - } + + let Certainty::Maybe(maybe_cause) = responses.iter().fold( + Certainty::AMBIGUOUS, + |certainty, response| { + certainty.unify_with(response.value.certainty) + }, + ) else { + bug!("expected flounder response to be ambiguous") + }; + + Ok(self.make_ambiguous_response_no_constraints(maybe_cause)) } } diff --git a/compiler/rustc_trait_selection/src/solve/opaques.rs b/compiler/rustc_trait_selection/src/solve/opaques.rs new file mode 100644 index 000000000..a5de4ddee --- /dev/null +++ b/compiler/rustc_trait_selection/src/solve/opaques.rs @@ -0,0 +1,67 @@ +use rustc_middle::traits::query::NoSolution; +use rustc_middle::traits::solve::{Certainty, Goal, QueryResult}; +use rustc_middle::traits::Reveal; +use rustc_middle::ty; +use rustc_middle::ty::util::NotUniqueParam; + +use super::{EvalCtxt, SolverMode}; + +impl<'tcx> EvalCtxt<'_, 'tcx> { + pub(super) fn normalize_opaque_type( + &mut self, + goal: Goal<'tcx, ty::ProjectionPredicate<'tcx>>, + ) -> QueryResult<'tcx> { + let tcx = self.tcx(); + let opaque_ty = goal.predicate.projection_ty; + let expected = goal.predicate.term.ty().expect("no such thing as an opaque const"); + + match (goal.param_env.reveal(), self.solver_mode()) { + (Reveal::UserFacing, SolverMode::Normal) => { + let Some(opaque_ty_def_id) = opaque_ty.def_id.as_local() else { + return Err(NoSolution); + }; + let opaque_ty = + ty::OpaqueTypeKey { def_id: opaque_ty_def_id, substs: opaque_ty.substs }; + // FIXME: at some point we should call queries without defining + // new opaque types but having the existing opaque type definitions. + // This will require moving this below "Prefer opaques registered already". + if !self.can_define_opaque_ty(opaque_ty_def_id) { + return Err(NoSolution); + } + // FIXME: This may have issues when the substs contain aliases... + match self.tcx().uses_unique_placeholders_ignoring_regions(opaque_ty.substs) { + Err(NotUniqueParam::NotParam(param)) if param.is_non_region_infer() => { + return self.evaluate_added_goals_and_make_canonical_response( + Certainty::AMBIGUOUS, + ); + } + Err(_) => { + return Err(NoSolution); + } + Ok(()) => {} + } + // Prefer opaques registered already. + let matches = self.unify_existing_opaque_tys(goal.param_env, opaque_ty, expected); + if !matches.is_empty() { + if let Some(response) = self.try_merge_responses(&matches) { + return Ok(response); + } else { + return self.flounder(&matches); + } + } + // Otherwise, define a new opaque type + self.register_opaque_ty(opaque_ty, expected, goal.param_env)?; + self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + } + (Reveal::UserFacing, SolverMode::Coherence) => { + self.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS) + } + (Reveal::All, _) => { + // FIXME: Add an assertion that opaque type storage is empty. + let actual = tcx.type_of(opaque_ty.def_id).subst(tcx, opaque_ty.substs); + self.eq(goal.param_env, expected, actual)?; + self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + } + } + } +} diff --git a/compiler/rustc_trait_selection/src/solve/project_goals.rs b/compiler/rustc_trait_selection/src/solve/project_goals.rs index 14cb43b89..7d7dfa2c8 100644 --- a/compiler/rustc_trait_selection/src/solve/project_goals.rs +++ b/compiler/rustc_trait_selection/src/solve/project_goals.rs @@ -22,19 +22,25 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { &mut self, goal: Goal<'tcx, ProjectionPredicate<'tcx>>, ) -> QueryResult<'tcx> { - // To only compute normalization once for each projection we only - // normalize if the expected term is an unconstrained inference variable. - // - // E.g. for `<T as Trait>::Assoc == u32` we recursively compute the goal - // `exists<U> <T as Trait>::Assoc == U` and then take the resulting type for - // `U` and equate it with `u32`. This means that we don't need a separate - // projection cache in the solver. - if self.term_is_fully_unconstrained(goal) { - let candidates = self.assemble_and_evaluate_candidates(goal); - self.merge_candidates(candidates) - } else { - self.set_normalizes_to_hack_goal(goal); - self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + match goal.predicate.projection_ty.kind(self.tcx()) { + ty::AliasKind::Projection => { + // To only compute normalization once for each projection we only + // normalize if the expected term is an unconstrained inference variable. + // + // E.g. for `<T as Trait>::Assoc == u32` we recursively compute the goal + // `exists<U> <T as Trait>::Assoc == U` and then take the resulting type for + // `U` and equate it with `u32`. This means that we don't need a separate + // projection cache in the solver. + if self.term_is_fully_unconstrained(goal) { + let candidates = self.assemble_and_evaluate_candidates(goal); + self.merge_candidates(candidates) + } else { + self.set_normalizes_to_hack_goal(goal); + self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + } + } + ty::AliasKind::Opaque => self.normalize_opaque_type(goal), + ty::AliasKind::Inherent => bug!("IATs not supported here yet"), } } } @@ -56,11 +62,11 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> { self.trait_def_id(tcx) } - fn consider_implied_clause( + fn probe_and_match_goal_against_assumption( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, assumption: ty::Predicate<'tcx>, - requirements: impl IntoIterator<Item = Goal<'tcx, ty::Predicate<'tcx>>>, + then: impl FnOnce(&mut EvalCtxt<'_, 'tcx>) -> QueryResult<'tcx>, ) -> QueryResult<'tcx> { if let Some(poly_projection_pred) = assumption.to_opt_poly_projection_pred() && poly_projection_pred.projection_def_id() == goal.predicate.def_id() @@ -73,49 +79,9 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> { goal.predicate.projection_ty, assumption_projection_pred.projection_ty, )?; - ecx.eq(goal.param_env, goal.predicate.term, assumption_projection_pred.term)?; - ecx.add_goals(requirements); - ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) - }) - } else { - Err(NoSolution) - } - } - - fn consider_object_bound_candidate( - ecx: &mut EvalCtxt<'_, 'tcx>, - goal: Goal<'tcx, Self>, - assumption: ty::Predicate<'tcx>, - ) -> QueryResult<'tcx> { - if let Some(poly_projection_pred) = assumption.to_opt_poly_projection_pred() - && poly_projection_pred.projection_def_id() == goal.predicate.def_id() - { - ecx.probe(|ecx| { - let tcx = ecx.tcx(); - - let assumption_projection_pred = - ecx.instantiate_binder_with_infer(poly_projection_pred); - ecx.eq( - goal.param_env, - goal.predicate.projection_ty, - assumption_projection_pred.projection_ty, - )?; - - let ty::Dynamic(bounds, _, _) = *goal.predicate.self_ty().kind() else { - bug!("expected object type in `consider_object_bound_candidate`"); - }; - ecx.add_goals( - structural_traits::predicates_for_object_candidate( - &ecx, - goal.param_env, - goal.predicate.projection_ty.trait_ref(tcx), - bounds, - ) - .into_iter() - .map(|pred| goal.with(tcx, pred)), - ); - ecx.eq(goal.param_env, goal.predicate.term, assumption_projection_pred.term)?; - ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + ecx.eq(goal.param_env, goal.predicate.term, assumption_projection_pred.term) + .expect("expected goal term to be fully unconstrained"); + then(ecx) }) } else { Err(NoSolution) @@ -164,10 +130,24 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> { }; if !assoc_def.item.defaultness(tcx).has_value() { - tcx.sess.delay_span_bug( + let guar = tcx.sess.delay_span_bug( tcx.def_span(assoc_def.item.def_id), "missing value for assoc item in impl", ); + let error_term = match assoc_def.item.kind { + ty::AssocKind::Const => tcx + .const_error( + tcx.type_of(goal.predicate.def_id()) + .subst(tcx, goal.predicate.projection_ty.substs), + guar, + ) + .into(), + ty::AssocKind::Type => tcx.ty_error(guar).into(), + ty::AssocKind::Fn => unreachable!(), + }; + ecx.eq(goal.param_env, goal.predicate.term, error_term) + .expect("expected goal term to be fully unconstrained"); + return ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes); } // Getting the right substitutions here is complex, e.g. given: @@ -198,7 +178,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> { let term: ty::EarlyBinder<ty::Term<'tcx>> = if is_const { let identity_substs = ty::InternalSubsts::identity_for_item(tcx, assoc_def.item.def_id); - let did = ty::WithOptConstParam::unknown(assoc_def.item.def_id); + let did = assoc_def.item.def_id; let kind = ty::ConstKind::Unevaluated(ty::UnevaluatedConst::new(did, identity_substs)); ty.map_bound(|ty| tcx.mk_const(kind, ty).into()) @@ -206,7 +186,8 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> { ty.map_bound(|ty| ty.into()) }; - ecx.eq(goal.param_env, goal.predicate.term, term.subst(tcx, substs))?; + ecx.eq(goal.param_env, goal.predicate.term, term.subst(tcx, substs)) + .expect("expected goal term to be fully unconstrained"); ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) }) } @@ -271,8 +252,9 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> { .evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS); } }; - let output_is_sized_pred = tupled_inputs_and_output - .map_bound(|(_, output)| tcx.at(DUMMY_SP).mk_trait_ref(LangItem::Sized, [output])); + let output_is_sized_pred = tupled_inputs_and_output.map_bound(|(_, output)| { + ty::TraitRef::from_lang_item(tcx, LangItem::Sized, DUMMY_SP, [output]) + }); let pred = tupled_inputs_and_output .map_bound(|(inputs, output)| ty::ProjectionPredicate { @@ -330,10 +312,12 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> { ty::Alias(_, _) | ty::Param(_) | ty::Placeholder(..) => { // FIXME(ptr_metadata): It would also be possible to return a `Ok(Ambig)` with no constraints. - let sized_predicate = ty::Binder::dummy(tcx.at(DUMMY_SP).mk_trait_ref( + let sized_predicate = ty::TraitRef::from_lang_item( + tcx, LangItem::Sized, + DUMMY_SP, [ty::GenericArg::from(goal.predicate.self_ty())], - )); + ); ecx.add_goal(goal.with(tcx, sized_predicate)); tcx.types.unit } @@ -375,7 +359,8 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> { ), }; - ecx.eq(goal.param_env, goal.predicate.term, metadata_ty.into())?; + ecx.eq(goal.param_env, goal.predicate.term, metadata_ty.into()) + .expect("expected goal term to be fully unconstrained"); ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) }) } @@ -513,7 +498,8 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> { }; ecx.probe(|ecx| { - ecx.eq(goal.param_env, goal.predicate.term, discriminant_ty.into())?; + ecx.eq(goal.param_env, goal.predicate.term, discriminant_ty.into()) + .expect("expected goal term to be fully unconstrained"); ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) }) } diff --git a/compiler/rustc_trait_selection/src/solve/search_graph/cache.rs b/compiler/rustc_trait_selection/src/solve/search_graph/cache.rs index d1b4fa554..56f126e91 100644 --- a/compiler/rustc_trait_selection/src/solve/search_graph/cache.rs +++ b/compiler/rustc_trait_selection/src/solve/search_graph/cache.rs @@ -10,8 +10,8 @@ //! before then or if I still haven't done that before January 2023. use super::StackDepth; use rustc_data_structures::fx::FxHashMap; -use rustc_index::vec::IndexVec; -use rustc_middle::traits::solve::{CanonicalGoal, QueryResult}; +use rustc_index::IndexVec; +use rustc_middle::traits::solve::{CanonicalInput, QueryResult}; rustc_index::newtype_index! { pub struct EntryIndex {} @@ -34,7 +34,7 @@ pub(super) struct ProvisionalEntry<'tcx> { // The goal for this entry. Should always be equal to the corresponding goal // in the lookup table. - pub(super) goal: CanonicalGoal<'tcx>, + pub(super) input: CanonicalInput<'tcx>, } pub(super) struct ProvisionalCache<'tcx> { @@ -42,7 +42,7 @@ pub(super) struct ProvisionalCache<'tcx> { // FIXME: This is only used to quickly check whether a given goal // is in the cache. We should experiment with using something like // `SsoHashSet` here because in most cases there are only a few entries. - pub(super) lookup_table: FxHashMap<CanonicalGoal<'tcx>, EntryIndex>, + pub(super) lookup_table: FxHashMap<CanonicalInput<'tcx>, EntryIndex>, } impl<'tcx> ProvisionalCache<'tcx> { diff --git a/compiler/rustc_trait_selection/src/solve/search_graph/mod.rs b/compiler/rustc_trait_selection/src/solve/search_graph/mod.rs index 050269fa9..19e4b2300 100644 --- a/compiler/rustc_trait_selection/src/solve/search_graph/mod.rs +++ b/compiler/rustc_trait_selection/src/solve/search_graph/mod.rs @@ -6,9 +6,9 @@ pub(super) use overflow::OverflowHandler; use self::cache::ProvisionalEntry; use cache::ProvisionalCache; use overflow::OverflowData; -use rustc_index::vec::IndexVec; +use rustc_index::IndexVec; use rustc_middle::dep_graph::DepKind; -use rustc_middle::traits::solve::{CanonicalGoal, Certainty, MaybeCause, QueryResult}; +use rustc_middle::traits::solve::{CanonicalInput, Certainty, MaybeCause, QueryResult}; use rustc_middle::ty::TyCtxt; use std::{collections::hash_map::Entry, mem}; @@ -19,7 +19,7 @@ rustc_index::newtype_index! { } struct StackElem<'tcx> { - goal: CanonicalGoal<'tcx>, + input: CanonicalInput<'tcx>, has_been_used: bool, } @@ -77,7 +77,7 @@ impl<'tcx> SearchGraph<'tcx> { } // ...or it depends on a goal with a lower depth. - let current_goal = self.stack[stack_depth].goal; + let current_goal = self.stack[stack_depth].input; let entry_index = self.provisional_cache.lookup_table[¤t_goal]; self.provisional_cache.entries[entry_index].depth != stack_depth } else { @@ -92,20 +92,20 @@ impl<'tcx> SearchGraph<'tcx> { fn try_push_stack( &mut self, tcx: TyCtxt<'tcx>, - goal: CanonicalGoal<'tcx>, + input: CanonicalInput<'tcx>, ) -> Result<(), QueryResult<'tcx>> { // Look at the provisional cache to check for cycles. let cache = &mut self.provisional_cache; - match cache.lookup_table.entry(goal) { + match cache.lookup_table.entry(input) { // No entry, simply push this goal on the stack after dealing with overflow. Entry::Vacant(v) => { if self.overflow_data.has_overflow(self.stack.len()) { - return Err(self.deal_with_overflow(tcx, goal)); + return Err(self.deal_with_overflow(tcx, input)); } - let depth = self.stack.push(StackElem { goal, has_been_used: false }); - let response = super::response_no_constraints(tcx, goal, Certainty::Yes); - let entry_index = cache.entries.push(ProvisionalEntry { response, depth, goal }); + let depth = self.stack.push(StackElem { input, has_been_used: false }); + let response = super::response_no_constraints(tcx, input, Certainty::Yes); + let entry_index = cache.entries.push(ProvisionalEntry { response, depth, input }); v.insert(entry_index); Ok(()) } @@ -135,13 +135,13 @@ impl<'tcx> SearchGraph<'tcx> { // the stack is enough. if self.stack.raw[stack_depth.index()..] .iter() - .all(|g| g.goal.value.predicate.is_coinductive(tcx)) + .all(|g| g.input.value.goal.predicate.is_coinductive(tcx)) { Err(cache.provisional_result(entry_index)) } else { Err(super::response_no_constraints( tcx, - goal, + input, Certainty::Maybe(MaybeCause::Overflow), )) } @@ -161,18 +161,18 @@ impl<'tcx> SearchGraph<'tcx> { /// updated the provisional cache and we have to recompute the current goal. /// /// FIXME: Refer to the rustc-dev-guide entry once it exists. - #[instrument(level = "debug", skip(self, actual_goal), ret)] + #[instrument(level = "debug", skip(self, actual_input), ret)] fn try_finalize_goal( &mut self, - actual_goal: CanonicalGoal<'tcx>, + actual_input: CanonicalInput<'tcx>, response: QueryResult<'tcx>, ) -> bool { let stack_elem = self.stack.pop().unwrap(); - let StackElem { goal, has_been_used } = stack_elem; - assert_eq!(goal, actual_goal); + let StackElem { input, has_been_used } = stack_elem; + assert_eq!(input, actual_input); let cache = &mut self.provisional_cache; - let provisional_entry_index = *cache.lookup_table.get(&goal).unwrap(); + let provisional_entry_index = *cache.lookup_table.get(&input).unwrap(); let provisional_entry = &mut cache.entries[provisional_entry_index]; // We eagerly update the response in the cache here. If we have to reevaluate // this goal we use the new response when hitting a cycle, and we definitely @@ -194,7 +194,7 @@ impl<'tcx> SearchGraph<'tcx> { cache.entries.truncate(provisional_entry_index.index() + 1); // ...and finally push our goal back on the stack and reevaluate it. - self.stack.push(StackElem { goal, has_been_used: false }); + self.stack.push(StackElem { input, has_been_used: false }); false } else { true @@ -204,17 +204,17 @@ impl<'tcx> SearchGraph<'tcx> { pub(super) fn with_new_goal( &mut self, tcx: TyCtxt<'tcx>, - canonical_goal: CanonicalGoal<'tcx>, + canonical_input: CanonicalInput<'tcx>, mut loop_body: impl FnMut(&mut Self) -> QueryResult<'tcx>, ) -> QueryResult<'tcx> { if self.should_use_global_cache() { - if let Some(result) = tcx.new_solver_evaluation_cache.get(&canonical_goal, tcx) { - debug!(?canonical_goal, ?result, "cache hit"); + if let Some(result) = tcx.new_solver_evaluation_cache.get(&canonical_input, tcx) { + debug!(?canonical_input, ?result, "cache hit"); return result; } } - match self.try_push_stack(tcx, canonical_goal) { + match self.try_push_stack(tcx, canonical_input) { Ok(()) => {} // Our goal is already on the stack, eager return. Err(response) => return response, @@ -226,19 +226,19 @@ impl<'tcx> SearchGraph<'tcx> { let (result, dep_node) = tcx.dep_graph.with_anon_task(tcx, DepKind::TraitSelect, || { self.repeat_while_none( |this| { - let result = this.deal_with_overflow(tcx, canonical_goal); + let result = this.deal_with_overflow(tcx, canonical_input); let _ = this.stack.pop().unwrap(); result }, |this| { let result = loop_body(this); - this.try_finalize_goal(canonical_goal, result).then(|| result) + this.try_finalize_goal(canonical_input, result).then(|| result) }, ) }); let cache = &mut self.provisional_cache; - let provisional_entry_index = *cache.lookup_table.get(&canonical_goal).unwrap(); + let provisional_entry_index = *cache.lookup_table.get(&canonical_input).unwrap(); let provisional_entry = &mut cache.entries[provisional_entry_index]; let depth = provisional_entry.depth; @@ -254,13 +254,13 @@ impl<'tcx> SearchGraph<'tcx> { // cycle participants without moving them to the global cache. let other_cycle_participants = provisional_entry_index.index() + 1; for (i, entry) in cache.entries.drain_enumerated(other_cycle_participants..) { - let actual_index = cache.lookup_table.remove(&entry.goal); + let actual_index = cache.lookup_table.remove(&entry.input); debug_assert_eq!(Some(i), actual_index); debug_assert!(entry.depth == depth); } let current_goal = cache.entries.pop().unwrap(); - let actual_index = cache.lookup_table.remove(¤t_goal.goal); + let actual_index = cache.lookup_table.remove(¤t_goal.input); debug_assert_eq!(Some(provisional_entry_index), actual_index); debug_assert!(current_goal.depth == depth); @@ -274,7 +274,7 @@ impl<'tcx> SearchGraph<'tcx> { let can_cache = !self.overflow_data.did_overflow() || self.stack.is_empty(); if self.should_use_global_cache() && can_cache { tcx.new_solver_evaluation_cache.insert( - current_goal.goal, + current_goal.input, dep_node, current_goal.response, ); diff --git a/compiler/rustc_trait_selection/src/solve/trait_goals.rs b/compiler/rustc_trait_selection/src/solve/trait_goals.rs index abd11a15a..f722f2813 100644 --- a/compiler/rustc_trait_selection/src/solve/trait_goals.rs +++ b/compiler/rustc_trait_selection/src/solve/trait_goals.rs @@ -78,16 +78,17 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { }) } - fn consider_implied_clause( + fn probe_and_match_goal_against_assumption( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, assumption: ty::Predicate<'tcx>, - requirements: impl IntoIterator<Item = Goal<'tcx, ty::Predicate<'tcx>>>, + then: impl FnOnce(&mut EvalCtxt<'_, 'tcx>) -> QueryResult<'tcx>, ) -> QueryResult<'tcx> { if let Some(poly_trait_pred) = assumption.to_opt_poly_trait_pred() && poly_trait_pred.def_id() == goal.predicate.def_id() + && poly_trait_pred.polarity() == goal.predicate.polarity { - // FIXME: Constness and polarity + // FIXME: Constness ecx.probe(|ecx| { let assumption_trait_pred = ecx.instantiate_binder_with_infer(poly_trait_pred); @@ -96,57 +97,21 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { goal.predicate.trait_ref, assumption_trait_pred.trait_ref, )?; - ecx.add_goals(requirements); - ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + then(ecx) }) } else { Err(NoSolution) } } - fn consider_object_bound_candidate( + fn consider_auto_trait_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - assumption: ty::Predicate<'tcx>, ) -> QueryResult<'tcx> { - if let Some(poly_trait_pred) = assumption.to_opt_poly_trait_pred() - && poly_trait_pred.def_id() == goal.predicate.def_id() - { - // FIXME: Constness and polarity - ecx.probe(|ecx| { - let assumption_trait_pred = - ecx.instantiate_binder_with_infer(poly_trait_pred); - ecx.eq( - goal.param_env, - goal.predicate.trait_ref, - assumption_trait_pred.trait_ref, - )?; - - let tcx = ecx.tcx(); - let ty::Dynamic(bounds, _, _) = *goal.predicate.self_ty().kind() else { - bug!("expected object type in `consider_object_bound_candidate`"); - }; - ecx.add_goals( - structural_traits::predicates_for_object_candidate( - &ecx, - goal.param_env, - goal.predicate.trait_ref, - bounds, - ) - .into_iter() - .map(|pred| goal.with(tcx, pred)), - ); - ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) - }) - } else { - Err(NoSolution) + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); } - } - fn consider_auto_trait_candidate( - ecx: &mut EvalCtxt<'_, 'tcx>, - goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { if let Some(result) = ecx.disqualify_auto_trait_candidate_due_to_possible_impl(goal) { return result; } @@ -161,6 +126,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); + } + let tcx = ecx.tcx(); ecx.probe(|ecx| { @@ -176,6 +145,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); + } + ecx.probe_and_evaluate_goal_for_constituent_tys( goal, structural_traits::instantiate_constituent_tys_for_sized_trait, @@ -186,6 +159,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); + } + ecx.probe_and_evaluate_goal_for_constituent_tys( goal, structural_traits::instantiate_constituent_tys_for_copy_clone_trait, @@ -196,14 +173,22 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx> { - if goal.predicate.self_ty().has_non_region_infer() { - return ecx.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS); + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); } + // The regions of a type don't affect the size of the type let tcx = ecx.tcx(); - let self_ty = tcx.erase_regions(goal.predicate.self_ty()); + // We should erase regions from both the param-env and type, since both + // may have infer regions. Specifically, after canonicalizing and instantiating, + // early bound regions turn into region vars in both the new and old solver. + let key = tcx.erase_regions(goal.param_env.and(goal.predicate.self_ty())); + // But if there are inference variables, we have to wait until it's resolved. + if key.has_non_region_infer() { + return ecx.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS); + } - if let Ok(layout) = tcx.layout_of(goal.param_env.and(self_ty)) + if let Ok(layout) = tcx.layout_of(key) && layout.layout.is_pointer_like(&tcx.data_layout) { // FIXME: We could make this faster by making a no-constraints response @@ -217,6 +202,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); + } + if let ty::FnPtr(..) = goal.predicate.self_ty().kind() { ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) } else { @@ -229,6 +218,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { goal: Goal<'tcx, Self>, goal_kind: ty::ClosureKind, ) -> QueryResult<'tcx> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); + } + let tcx = ecx.tcx(); let tupled_inputs_and_output = match structural_traits::extract_tupled_inputs_and_output_from_callable( @@ -242,12 +235,13 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { .evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS); } }; - let output_is_sized_pred = tupled_inputs_and_output - .map_bound(|(_, output)| tcx.at(DUMMY_SP).mk_trait_ref(LangItem::Sized, [output])); + let output_is_sized_pred = tupled_inputs_and_output.map_bound(|(_, output)| { + ty::TraitRef::from_lang_item(tcx, LangItem::Sized, DUMMY_SP, [output]) + }); let pred = tupled_inputs_and_output .map_bound(|(inputs, _)| { - tcx.mk_trait_ref(goal.predicate.def_id(), [goal.predicate.self_ty(), inputs]) + ty::TraitRef::new(tcx, goal.predicate.def_id(), [goal.predicate.self_ty(), inputs]) }) .to_predicate(tcx); // A built-in `Fn` impl only holds if the output is sized. @@ -259,6 +253,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); + } + if let ty::Tuple(..) = goal.predicate.self_ty().kind() { ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) } else { @@ -268,8 +266,12 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { fn consider_builtin_pointee_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, - _goal: Goal<'tcx, Self>, + goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); + } + ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) } @@ -277,6 +279,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); + } + let ty::Generator(def_id, _, _) = *goal.predicate.self_ty().kind() else { return Err(NoSolution); }; @@ -297,6 +303,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); + } + let self_ty = goal.predicate.self_ty(); let ty::Generator(def_id, substs, _) = *self_ty.kind() else { return Err(NoSolution); @@ -312,10 +322,8 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { Self::consider_implied_clause( ecx, goal, - ty::Binder::dummy( - tcx.mk_trait_ref(goal.predicate.def_id(), [self_ty, generator.resume_ty()]), - ) - .to_predicate(tcx), + ty::TraitRef::new(tcx, goal.predicate.def_id(), [self_ty, generator.resume_ty()]) + .to_predicate(tcx), // Technically, we need to check that the generator types are Sized, // but that's already proven by the generator being WF. [], @@ -326,6 +334,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); + } + let tcx = ecx.tcx(); let a_ty = goal.predicate.self_ty(); let b_ty = goal.predicate.trait_ref.substs.type_at(1); @@ -346,7 +358,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { // Can only unsize to an object-safe type if data .principal_def_id() - .map_or(false, |def_id| !tcx.check_is_object_safe(def_id)) + .is_some_and(|def_id| !tcx.check_is_object_safe(def_id)) { return Err(NoSolution); } @@ -360,9 +372,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { data.iter().map(|pred| goal.with(tcx, pred.with_self_ty(tcx, a_ty))), ); // The type must be Sized to be unsized. - ecx.add_goal( - goal.with(tcx, ty::Binder::dummy(tcx.mk_trait_ref(sized_def_id, [a_ty]))), - ); + ecx.add_goal(goal.with(tcx, ty::TraitRef::new(tcx, sized_def_id, [a_ty]))); // The type must outlive the lifetime of the `dyn` we're unsizing into. ecx.add_goal( goal.with(tcx, ty::Binder::dummy(ty::OutlivesPredicate(a_ty, region))), @@ -411,9 +421,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ecx.eq(goal.param_env, unsized_a_ty, b_ty)?; ecx.add_goal(goal.with( tcx, - ty::Binder::dummy( - tcx.mk_trait_ref(goal.predicate.def_id(), [a_tail_ty, b_tail_ty]), - ), + ty::TraitRef::new(tcx, goal.predicate.def_id(), [a_tail_ty, b_tail_ty]), )); ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) } @@ -432,9 +440,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { // Similar to ADTs, require that the rest of the fields are equal. ecx.add_goal(goal.with( tcx, - ty::Binder::dummy( - tcx.mk_trait_ref(goal.predicate.def_id(), [*a_last_ty, *b_last_ty]), - ), + ty::TraitRef::new(tcx, goal.predicate.def_id(), [*a_last_ty, *b_last_ty]), )); ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) } @@ -447,6 +453,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, ) -> Vec<CanonicalResponse<'tcx>> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return vec![]; + } + let tcx = ecx.tcx(); let a_ty = goal.predicate.self_ty(); @@ -521,8 +531,12 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { fn consider_builtin_discriminant_kind_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, - _goal: Goal<'tcx, Self>, + goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); + } + // `DiscriminantKind` is automatically implemented for every type. ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) } @@ -531,6 +545,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); + } + if !goal.param_env.is_const() { // `Destruct` is automatically implemented for every type in // non-const environments. @@ -545,6 +563,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx> { + if goal.predicate.polarity != ty::ImplPolarity::Positive { + return Err(NoSolution); + } + // `rustc_transmute` does not have support for type or const params if goal.has_non_region_placeholders() { return Err(NoSolution); @@ -591,12 +613,12 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { Some(self.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS)) } - // These types cannot be structurally decomposed into constitutent + // These types cannot be structurally decomposed into constituent // types, and therefore have no built-in auto impl. ty::Dynamic(..) | ty::Param(..) | ty::Foreign(..) - | ty::Alias(ty::Projection, ..) + | ty::Alias(ty::Projection | ty::Inherent, ..) | ty::Placeholder(..) => Some(Err(NoSolution)), ty::Infer(_) | ty::Bound(_, _) => bug!("unexpected type `{self_ty}`"), @@ -645,12 +667,16 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { // FIXME: Handling opaques here is kinda sus. Especially because we // simplify them to PlaceholderSimplifiedType. | ty::Alias(ty::Opaque, _) => { - if let Some(def_id) = self.tcx().find_map_relevant_impl( + let mut disqualifying_impl = None; + self.tcx().for_each_relevant_impl_treating_projections( goal.predicate.def_id(), goal.predicate.self_ty(), TreatProjections::NextSolverLookup, - Some, - ) { + |impl_def_id| { + disqualifying_impl = Some(impl_def_id); + }, + ); + if let Some(def_id) = disqualifying_impl { debug!(?def_id, ?goal, "disqualified auto-trait implementation"); // No need to actually consider the candidate here, // since we do that in `consider_impl_candidate`. diff --git a/compiler/rustc_trait_selection/src/traits/auto_trait.rs b/compiler/rustc_trait_selection/src/traits/auto_trait.rs index 182d995c4..62d2aad52 100644 --- a/compiler/rustc_trait_selection/src/traits/auto_trait.rs +++ b/compiler/rustc_trait_selection/src/traits/auto_trait.rs @@ -86,7 +86,7 @@ impl<'tcx> AutoTraitFinder<'tcx> { ) -> AutoTraitResult<A> { let tcx = self.tcx; - let trait_ref = tcx.mk_trait_ref(trait_did, [ty]); + let trait_ref = ty::TraitRef::new(tcx, trait_did, [ty]); let infcx = tcx.infer_ctxt().build(); let mut selcx = SelectionContext::new(&infcx); @@ -263,7 +263,7 @@ impl<'tcx> AutoTraitFinder<'tcx> { let mut already_visited = FxHashSet::default(); let mut predicates = VecDeque::new(); predicates.push_back(ty::Binder::dummy(ty::TraitPredicate { - trait_ref: infcx.tcx.mk_trait_ref(trait_did, [ty]), + trait_ref: ty::TraitRef::new(infcx.tcx, trait_did, [ty]), constness: ty::BoundConstness::NotConst, // Auto traits are positive @@ -591,7 +591,7 @@ impl<'tcx> AutoTraitFinder<'tcx> { fn evaluate_nested_obligations( &self, ty: Ty<'_>, - nested: impl Iterator<Item = Obligation<'tcx, ty::Predicate<'tcx>>>, + nested: impl Iterator<Item = PredicateObligation<'tcx>>, computed_preds: &mut FxIndexSet<ty::Predicate<'tcx>>, fresh_preds: &mut FxHashSet<ty::Predicate<'tcx>>, predicates: &mut VecDeque<ty::PolyTraitPredicate<'tcx>>, @@ -796,13 +796,12 @@ impl<'tcx> AutoTraitFinder<'tcx> { Ok(Some(valtree)) => Ok(selcx.tcx().mk_const(valtree, c.ty())), Ok(None) => { let tcx = self.tcx; - let def_id = unevaluated.def.did; let reported = tcx.sess.emit_err(UnableToConstructConstantValue { - span: tcx.def_span(def_id), + span: tcx.def_span(unevaluated.def), unevaluated: unevaluated, }); - Err(ErrorHandled::Reported(reported)) + Err(ErrorHandled::Reported(reported.into())) } Err(err) => Err(err), } @@ -835,8 +834,10 @@ impl<'tcx> AutoTraitFinder<'tcx> { | ty::PredicateKind::Subtype(..) // FIXME(generic_const_exprs): you can absolutely add this as a where clauses | ty::PredicateKind::ConstEvaluatable(..) - | ty::PredicateKind::Coerce(..) - | ty::PredicateKind::TypeWellFormedFromEnv(..) => {} + | ty::PredicateKind::Coerce(..) => {} + ty::PredicateKind::TypeWellFormedFromEnv(..) => { + bug!("predicate should only exist in the environment: {bound_predicate:?}") + } ty::PredicateKind::Ambiguous => return false, }; } diff --git a/compiler/rustc_trait_selection/src/traits/coherence.rs b/compiler/rustc_trait_selection/src/traits/coherence.rs index 20c2605f2..e8c5a8fab 100644 --- a/compiler/rustc_trait_selection/src/traits/coherence.rs +++ b/compiler/rustc_trait_selection/src/traits/coherence.rs @@ -17,9 +17,10 @@ use crate::traits::{ use rustc_data_structures::fx::FxIndexSet; use rustc_errors::Diagnostic; use rustc_hir::def_id::{DefId, CRATE_DEF_ID, LOCAL_CRATE}; -use rustc_infer::infer::{DefineOpaqueTypes, DefiningAnchor, InferCtxt, TyCtxtInferExt}; +use rustc_infer::infer::{DefineOpaqueTypes, InferCtxt, TyCtxtInferExt}; use rustc_infer::traits::util; use rustc_middle::traits::specialization_graph::OverlapMode; +use rustc_middle::traits::DefiningAnchor; use rustc_middle::ty::fast_reject::{DeepRejectCtxt, TreatParams}; use rustc_middle::ty::visit::{TypeVisitable, TypeVisitableExt}; use rustc_middle::ty::{self, ImplSubject, Ty, TyCtxt, TypeVisitor}; @@ -322,7 +323,9 @@ fn negative_impl(tcx: TyCtxt<'_>, impl1_def_id: DefId, impl2_def_id: DefId) -> b let selcx = &mut SelectionContext::new(&infcx); let impl2_substs = infcx.fresh_substs_for_item(DUMMY_SP, impl2_def_id); let (subject2, obligations) = - impl_subject_and_oblig(selcx, impl_env, impl2_def_id, impl2_substs); + impl_subject_and_oblig(selcx, impl_env, impl2_def_id, impl2_substs, |_, _| { + ObligationCause::dummy() + }); !equate(&infcx, impl_env, subject1, subject2, obligations, impl1_def_id) } @@ -582,7 +585,7 @@ fn orphan_check_trait_ref<'tcx>( trait_ref: ty::TraitRef<'tcx>, in_crate: InCrate, ) -> Result<(), OrphanCheckErr<'tcx>> { - if trait_ref.needs_infer() && trait_ref.needs_subst() { + if trait_ref.has_infer() && trait_ref.has_param() { bug!( "can't orphan check a trait ref with both params and inference variables {:?}", trait_ref @@ -673,7 +676,7 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for OrphanChecker<'tcx> { | ty::RawPtr(..) | ty::Never | ty::Tuple(..) - | ty::Alias(ty::Projection, ..) => self.found_non_local_ty(ty), + | ty::Alias(ty::Projection | ty::Inherent, ..) => self.found_non_local_ty(ty), ty::Param(..) => self.found_param_ty(ty), @@ -704,7 +707,7 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for OrphanChecker<'tcx> { } ty::Dynamic(tt, ..) => { let principal = tt.principal().map(|p| p.def_id()); - if principal.map_or(false, |p| self.def_id_is_local(p)) { + if principal.is_some_and(|p| self.def_id_is_local(p)) { ControlFlow::Break(OrphanCheckEarlyExit::LocalTy(ty)) } else { self.found_non_local_ty(ty) diff --git a/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs b/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs index 345e84990..bd1ea43a7 100644 --- a/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs +++ b/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs @@ -44,7 +44,7 @@ pub fn is_const_evaluatable<'tcx>( let ct = tcx.expand_abstract_consts(unexpanded_ct); let is_anon_ct = if let ty::ConstKind::Unevaluated(uv) = ct.kind() { - tcx.def_kind(uv.def.did) == DefKind::AnonConst + tcx.def_kind(uv.def) == DefKind::AnonConst } else { false }; @@ -79,7 +79,7 @@ pub fn is_const_evaluatable<'tcx>( "Missing value for constant, but no error reported?", ))) } - Err(ErrorHandled::Reported(e)) => Err(NotConstEvaluatable::Error(e)), + Err(ErrorHandled::Reported(e)) => Err(NotConstEvaluatable::Error(e.into())), Ok(_) => Ok(()), } } @@ -119,7 +119,7 @@ pub fn is_const_evaluatable<'tcx>( tcx.sess .struct_span_fatal( // Slightly better span than just using `span` alone - if span == rustc_span::DUMMY_SP { tcx.def_span(uv.def.did) } else { span }, + if span == rustc_span::DUMMY_SP { tcx.def_span(uv.def) } else { span }, "failed to evaluate generic const expression", ) .note("the crate this constant originates from uses `#![feature(generic_const_exprs)]`") @@ -147,7 +147,7 @@ pub fn is_const_evaluatable<'tcx>( Err(err) } - Err(ErrorHandled::Reported(e)) => Err(NotConstEvaluatable::Error(e)), + Err(ErrorHandled::Reported(e)) => Err(NotConstEvaluatable::Error(e.into())), Ok(_) => Ok(()), } } diff --git a/compiler/rustc_trait_selection/src/traits/engine.rs b/compiler/rustc_trait_selection/src/traits/engine.rs index 2beebe94b..2c5ffd664 100644 --- a/compiler/rustc_trait_selection/src/traits/engine.rs +++ b/compiler/rustc_trait_selection/src/traits/engine.rs @@ -14,11 +14,11 @@ use rustc_infer::infer::canonical::{ }; use rustc_infer::infer::outlives::env::OutlivesEnvironment; use rustc_infer::infer::{DefineOpaqueTypes, InferCtxt, InferOk}; -use rustc_infer::traits::query::Fallible; use rustc_infer::traits::{ FulfillmentError, Obligation, ObligationCause, PredicateObligation, TraitEngineExt as _, }; use rustc_middle::arena::ArenaAllocatable; +use rustc_middle::traits::query::NoSolution; use rustc_middle::ty::error::TypeError; use rustc_middle::ty::ToPredicate; use rustc_middle::ty::TypeFoldable; @@ -97,7 +97,7 @@ impl<'a, 'tcx> ObligationCtxt<'a, 'tcx> { def_id: DefId, ) { let tcx = self.infcx.tcx; - let trait_ref = tcx.mk_trait_ref(def_id, [ty]); + let trait_ref = ty::TraitRef::new(tcx, def_id, [ty]); self.register_obligation(Obligation { cause, recursion_depth: 0, @@ -235,7 +235,7 @@ impl<'a, 'tcx> ObligationCtxt<'a, 'tcx> { &self, inference_vars: CanonicalVarValues<'tcx>, answer: T, - ) -> Fallible<CanonicalQueryResponse<'tcx, T>> + ) -> Result<CanonicalQueryResponse<'tcx, T>, NoSolution> where T: Debug + TypeFoldable<TyCtxt<'tcx>>, Canonical<'tcx, QueryResponse<'tcx, T>>: ArenaAllocatable<'tcx>, diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs index 0475f24d8..7ab652761 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs @@ -87,7 +87,7 @@ pub fn recompute_applicable_impls<'tcx>( if let ty::PredicateKind::Clause(ty::Clause::Trait(trait_pred)) = kind.skip_binder() && param_env_candidate_may_apply(kind.rebind(trait_pred)) { - if kind.rebind(trait_pred.trait_ref) == ty::TraitRef::identity(tcx, trait_pred.def_id()) { + if kind.rebind(trait_pred.trait_ref) == ty::Binder::dummy(ty::TraitRef::identity(tcx, trait_pred.def_id())) { ambiguities.push(Ambiguity::ParamEnv(tcx.def_span(trait_pred.def_id()))) } else { ambiguities.push(Ambiguity::ParamEnv(span)) diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/method_chain.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/method_chain.rs deleted file mode 100644 index 7e1dba4ed..000000000 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/method_chain.rs +++ /dev/null @@ -1,102 +0,0 @@ -use crate::infer::InferCtxt; - -use rustc_infer::infer::ObligationEmittingRelation; -use rustc_infer::traits::PredicateObligations; -use rustc_middle::ty::error::TypeError; -use rustc_middle::ty::relate::{self, Relate, RelateResult, TypeRelation}; -use rustc_middle::ty::{self, Ty, TyCtxt}; - -pub struct CollectAllMismatches<'a, 'tcx> { - pub infcx: &'a InferCtxt<'tcx>, - pub param_env: ty::ParamEnv<'tcx>, - pub errors: Vec<TypeError<'tcx>>, -} - -impl<'a, 'tcx> TypeRelation<'tcx> for CollectAllMismatches<'a, 'tcx> { - fn tag(&self) -> &'static str { - "CollectAllMismatches" - } - - fn tcx(&self) -> TyCtxt<'tcx> { - self.infcx.tcx - } - - fn param_env(&self) -> ty::ParamEnv<'tcx> { - self.param_env - } - - fn a_is_expected(&self) -> bool { - true - } - - fn relate_with_variance<T: Relate<'tcx>>( - &mut self, - _: ty::Variance, - _: ty::VarianceDiagInfo<'tcx>, - a: T, - b: T, - ) -> RelateResult<'tcx, T> { - self.relate(a, b) - } - - fn regions( - &mut self, - a: ty::Region<'tcx>, - _b: ty::Region<'tcx>, - ) -> RelateResult<'tcx, ty::Region<'tcx>> { - Ok(a) - } - - fn tys(&mut self, a: Ty<'tcx>, b: Ty<'tcx>) -> RelateResult<'tcx, Ty<'tcx>> { - self.infcx.probe(|_| { - if a.is_ty_var() || b.is_ty_var() { - Ok(a) - } else { - self.infcx.super_combine_tys(self, a, b).or_else(|e| { - self.errors.push(e); - Ok(a) - }) - } - }) - } - - fn consts( - &mut self, - a: ty::Const<'tcx>, - b: ty::Const<'tcx>, - ) -> RelateResult<'tcx, ty::Const<'tcx>> { - self.infcx.probe(|_| { - if a.is_ct_infer() || b.is_ct_infer() { - Ok(a) - } else { - relate::super_relate_consts(self, a, b) // could do something similar here for constants! - } - }) - } - - fn binders<T: Relate<'tcx>>( - &mut self, - a: ty::Binder<'tcx, T>, - b: ty::Binder<'tcx, T>, - ) -> RelateResult<'tcx, ty::Binder<'tcx, T>> { - Ok(a.rebind(self.relate(a.skip_binder(), b.skip_binder())?)) - } -} - -impl<'tcx> ObligationEmittingRelation<'tcx> for CollectAllMismatches<'_, 'tcx> { - fn alias_relate_direction(&self) -> ty::AliasRelationDirection { - // FIXME(deferred_projection_equality): We really should get rid of this relation. - ty::AliasRelationDirection::Equate - } - - fn register_obligations(&mut self, _obligations: PredicateObligations<'tcx>) { - // FIXME(deferred_projection_equality) - } - - fn register_predicates( - &mut self, - _obligations: impl IntoIterator<Item: ty::ToPredicate<'tcx>>, - ) { - // FIXME(deferred_projection_equality) - } -} diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs index 1b741b730..a10ececbb 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs @@ -1,5 +1,4 @@ mod ambiguity; -pub mod method_chain; pub mod on_unimplemented; pub mod suggestions; @@ -15,8 +14,7 @@ use crate::traits::query::evaluate_obligation::InferCtxtExt as _; use crate::traits::query::normalize::QueryNormalizeExt as _; use crate::traits::specialize::to_pretty_impl_header; use crate::traits::NormalizeExt; -use on_unimplemented::OnUnimplementedNote; -use on_unimplemented::TypeErrCtxtExt as _; +use on_unimplemented::{AppendConstMessage, OnUnimplementedNote, TypeErrCtxtExt as _}; use rustc_data_structures::fx::{FxHashMap, FxIndexMap}; use rustc_errors::{ pluralize, struct_span_err, Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed, @@ -30,9 +28,9 @@ use rustc_hir::{GenericParam, Item, Node}; use rustc_infer::infer::error_reporting::TypeErrCtxt; use rustc_infer::infer::{InferOk, TypeTrace}; use rustc_middle::traits::select::OverflowError; +use rustc_middle::traits::SelectionOutputTypeParameterMismatch; use rustc_middle::ty::abstract_const::NotConstEvaluatable; use rustc_middle::ty::error::{ExpectedFound, TypeError}; -use rustc_middle::ty::fast_reject::TreatProjections; use rustc_middle::ty::fold::{TypeFolder, TypeSuperFoldable}; use rustc_middle::ty::print::{with_forced_trimmed_paths, FmtPrinter, Print}; use rustc_middle::ty::{ @@ -273,7 +271,7 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> { let underscores = vec!["_"; expected_args.len()].join(", "); err.span_suggestion_verbose( closure_arg_span.unwrap_or(found_span), - &format!( + format!( "consider changing the closure to take and ignore the expected argument{}", pluralize!(expected_args.len()) ), @@ -360,7 +358,7 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> { span: DUMMY_SP, kind: TypeVariableOriginKind::MiscVariable, }); - let trait_ref = self.tcx.mk_trait_ref(trait_def_id, [ty.skip_binder(), var]); + let trait_ref = ty::TraitRef::new(self.tcx, trait_def_id, [ty.skip_binder(), var]); let obligation = Obligation::new( self.tcx, ObligationCause::dummy(), @@ -439,7 +437,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { // 1) strictly implied by another error. // 2) implied by an error with a smaller index. for error2 in error_set { - if error2.index.map_or(false, |index2| is_suppressed[index2]) { + if error2.index.is_some_and(|index2| is_suppressed[index2]) { // Avoid errors being suppressed by already-suppressed // errors, to prevent all errors from being suppressed // at once. @@ -467,7 +465,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { } } - self.tcx.sess.delay_span_bug(DUMMY_SP, "expected fullfillment errors") + self.tcx.sess.delay_span_bug(DUMMY_SP, "expected fulfillment errors") } /// Reports that an overflow has occurred and halts compilation. We @@ -561,6 +559,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { suggest_increasing_limit, |err| { self.note_obligation_cause_code( + obligation.cause.body_id, err, predicate, obligation.param_env, @@ -577,7 +576,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { Limit(0) => Limit(2), limit => limit * 2, }; - err.help(&format!( + err.help(format!( "consider increasing the recursion limit by adding a \ `#![recursion_limit = \"{}\"]` attribute to your crate (`{}`)", suggested_limit, @@ -707,42 +706,25 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { conversion on the error value using the `From` trait" .to_owned(), ), - Some(None), + Some(AppendConstMessage::Default), ) } else { (message, note, append_const_msg) }; - let err_msg = message - .and_then(|cannot_do_this| { - match (predicate_is_const, append_const_msg) { - // do nothing if predicate is not const - (false, _) => Some(cannot_do_this), - // suggested using default post message - (true, Some(None)) => { - Some(format!("{cannot_do_this} in const contexts")) - } - // overridden post message - (true, Some(Some(post_message))) => { - Some(format!("{cannot_do_this}{post_message}")) - } - // fallback to generic message - (true, None) => None, - } - }) - .unwrap_or_else(|| { - format!( - "the trait bound `{}` is not satisfied{}", - trait_predicate, post_message, - ) - }); + let err_msg = self.get_standard_error_message( + &trait_predicate, + message, + predicate_is_const, + append_const_msg, + post_message, + ); let (err_msg, safe_transmute_explanation) = if Some(trait_ref.def_id()) == self.tcx.lang_items().transmute_trait() { // Recompute the safe transmute reason and use that for the error reporting self.get_safe_transmute_error_and_reason( - trait_predicate, obligation.clone(), trait_ref, span, @@ -756,7 +738,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { if is_try_conversion && let Some(ret_span) = self.return_type_span(&obligation) { err.span_label( ret_span, - &format!( + format!( "expected `{}` because of this", trait_ref.skip_binder().self_ty() ), @@ -764,22 +746,10 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { } if Some(trait_ref.def_id()) == tcx.lang_items().tuple_trait() { - match obligation.cause.code().peel_derives() { - ObligationCauseCode::RustCall => { - err.set_primary_message("functions with the \"rust-call\" ABI must take a single non-self tuple argument"); - } - ObligationCauseCode::BindingObligation(def_id, _) - | ObligationCauseCode::ItemObligation(def_id) - if tcx.is_fn_trait(*def_id) => - { - err.code(rustc_errors::error_code!(E0059)); - err.set_primary_message(format!( - "type parameter to bare `{}` trait must be a tuple", - tcx.def_path_str(*def_id) - )); - } - _ => {} - } + self.add_tuple_trait_message( + &obligation.cause.code().peel_derives(), + &mut err, + ); } if Some(trait_ref.def_id()) == tcx.lang_items().drop_trait() @@ -789,33 +759,13 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { err.note("See <https://github.com/rust-lang/rust/pull/94901> for more details"); } - let explanation = if let ObligationCauseCode::MainFunctionType = - obligation.cause.code() - { - "consider using `()`, or a `Result`".to_owned() - } else { - let ty_desc = match trait_ref.skip_binder().self_ty().kind() { - ty::FnDef(_, _) => Some("fn item"), - ty::Closure(_, _) => Some("closure"), - _ => None, - }; + let explanation = get_explanation_based_on_obligation( + &obligation, + trait_ref, + &trait_predicate, + pre_message, + ); - match ty_desc { - Some(desc) => format!( - "{}the trait `{}` is not implemented for {} `{}`", - pre_message, - trait_predicate.print_modifiers_and_trait_path(), - desc, - trait_ref.skip_binder().self_ty(), - ), - None => format!( - "{}the trait `{}` is not implemented for `{}`", - pre_message, - trait_predicate.print_modifiers_and_trait_path(), - trait_ref.skip_binder().self_ty(), - ), - } - }; self.check_for_binding_assigned_block_without_tail_expression( &obligation, &mut err, @@ -831,7 +781,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { err.emit(); return; } - if let Some(ref s) = label { + if let Some(s) = label { // If it has a custom `#[rustc_on_unimplemented]` // error message, let's display it as the label! err.span_label(span, s); @@ -839,7 +789,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { // When the self type is a type param We don't need to "the trait // `std::marker::Sized` is not implemented for `T`" as we will point // at the type param with a label to suggest constraining it. - err.help(&explanation); + err.help(explanation); } } else if let Some(custom_explanation) = safe_transmute_explanation { err.span_label(span, custom_explanation); @@ -847,42 +797,36 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { err.span_label(span, explanation); } - if let ObligationCauseCode::ObjectCastObligation(concrete_ty, obj_ty) = obligation.cause.code().peel_derives() && - Some(trait_ref.def_id()) == self.tcx.lang_items().sized_trait() { - self.suggest_borrowing_for_object_cast(&mut err, &root_obligation, *concrete_ty, *obj_ty); - } - - let mut unsatisfied_const = false; - if trait_predicate.is_const_if_const() && obligation.param_env.is_const() { - let non_const_predicate = trait_ref.without_const(); - let non_const_obligation = Obligation { - cause: obligation.cause.clone(), - param_env: obligation.param_env.without_const(), - predicate: non_const_predicate.to_predicate(tcx), - recursion_depth: obligation.recursion_depth, - }; - if self.predicate_may_hold(&non_const_obligation) { - unsatisfied_const = true; - err.span_note( - span, - &format!( - "the trait `{}` is implemented for `{}`, \ - but that implementation is not `const`", - non_const_predicate.print_modifiers_and_trait_path(), - trait_ref.skip_binder().self_ty(), - ), + if let ObligationCauseCode::Coercion { source, target } = + *obligation.cause.code().peel_derives() + { + if Some(trait_ref.def_id()) == self.tcx.lang_items().sized_trait() { + self.suggest_borrowing_for_object_cast( + &mut err, + &root_obligation, + source, + target, ); } } + let UnsatisfiedConst(unsatisfied_const) = self + .maybe_add_note_for_unsatisfied_const( + &obligation, + trait_ref, + &trait_predicate, + &mut err, + span, + ); + if let Some((msg, span)) = type_def { - err.span_label(span, &msg); + err.span_label(span, msg); } - if let Some(ref s) = note { + if let Some(s) = note { // If it has a custom `#[rustc_on_unimplemented]` note, let's display it - err.note(s.as_str()); + err.note(s); } - if let Some(ref s) = parent_label { + if let Some(s) = parent_label { let body = obligation.cause.body_id; err.span_label(tcx.def_span(body), s); } @@ -941,7 +885,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { return; } - if self.suggest_impl_trait(&mut err, span, &obligation, trait_predicate) { + if self.suggest_impl_trait(&mut err, &obligation, trait_predicate) { err.emit(); return; } @@ -971,137 +915,16 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { ); } - let body_def_id = obligation.cause.body_id; - // Try to report a help message - if is_fn_trait - && let Ok((implemented_kind, params)) = self.type_implements_fn_trait( - obligation.param_env, - trait_ref.self_ty(), - trait_predicate.skip_binder().constness, - trait_predicate.skip_binder().polarity, - ) - { - // If the type implements `Fn`, `FnMut`, or `FnOnce`, suppress the following - // suggestion to add trait bounds for the type, since we only typically implement - // these traits once. - - // Note if the `FnMut` or `FnOnce` is less general than the trait we're trying - // to implement. - let selected_kind = - self.tcx.fn_trait_kind_from_def_id(trait_ref.def_id()) - .expect("expected to map DefId to ClosureKind"); - if !implemented_kind.extends(selected_kind) { - err.note( - &format!( - "`{}` implements `{}`, but it must implement `{}`, which is more general", - trait_ref.skip_binder().self_ty(), - implemented_kind, - selected_kind - ) - ); - } - - // Note any argument mismatches - let given_ty = params.skip_binder(); - let expected_ty = trait_ref.skip_binder().substs.type_at(1); - if let ty::Tuple(given) = given_ty.kind() - && let ty::Tuple(expected) = expected_ty.kind() - { - if expected.len() != given.len() { - // Note number of types that were expected and given - err.note( - &format!( - "expected a closure taking {} argument{}, but one taking {} argument{} was given", - given.len(), - pluralize!(given.len()), - expected.len(), - pluralize!(expected.len()), - ) - ); - } else if !self.same_type_modulo_infer(given_ty, expected_ty) { - // Print type mismatch - let (expected_args, given_args) = - self.cmp(given_ty, expected_ty); - err.note_expected_found( - &"a closure with arguments", - expected_args, - &"a closure with arguments", - given_args, - ); - } - } - } else if !trait_ref.has_non_region_infer() - && self.predicate_can_apply(obligation.param_env, trait_predicate) - { - // If a where-clause may be useful, remind the - // user that they can add it. - // - // don't display an on-unimplemented note, as - // these notes will often be of the form - // "the type `T` can't be frobnicated" - // which is somewhat confusing. - self.suggest_restricting_param_bound( - &mut err, - trait_predicate, - None, - obligation.cause.body_id, - ); - } else if !suggested && !unsatisfied_const { - // Can't show anything else useful, try to find similar impls. - let impl_candidates = self.find_similar_impl_candidates(trait_predicate); - if !self.report_similar_impl_candidates( - &impl_candidates, - trait_ref, - body_def_id, - &mut err, - true, - ) { - // This is *almost* equivalent to - // `obligation.cause.code().peel_derives()`, but it gives us the - // trait predicate for that corresponding root obligation. This - // lets us get a derived obligation from a type parameter, like - // when calling `string.strip_suffix(p)` where `p` is *not* an - // implementer of `Pattern<'_>`. - let mut code = obligation.cause.code(); - let mut trait_pred = trait_predicate; - let mut peeled = false; - while let Some((parent_code, parent_trait_pred)) = code.parent() { - code = parent_code; - if let Some(parent_trait_pred) = parent_trait_pred { - trait_pred = parent_trait_pred; - peeled = true; - } - } - let def_id = trait_pred.def_id(); - // Mention *all* the `impl`s for the *top most* obligation, the - // user might have meant to use one of them, if any found. We skip - // auto-traits or fundamental traits that might not be exactly what - // the user might expect to be presented with. Instead this is - // useful for less general traits. - if peeled - && !self.tcx.trait_is_auto(def_id) - && !self.tcx.lang_items().iter().any(|(_, id)| id == def_id) - { - let trait_ref = trait_pred.to_poly_trait_ref(); - let impl_candidates = - self.find_similar_impl_candidates(trait_pred); - self.report_similar_impl_candidates( - &impl_candidates, - trait_ref, - body_def_id, - &mut err, - true, - ); - } - } - - self.maybe_suggest_convert_to_slice( - &mut err, - trait_ref, - impl_candidates.as_slice(), - span, - ); - } + self.try_to_add_help_message( + &obligation, + trait_ref, + &trait_predicate, + &mut err, + span, + is_fn_trait, + suggested, + unsatisfied_const, + ); // Changing mutability doesn't make a difference to whether we have // an `Unsize` impl (Fixes ICE in #71036) @@ -1196,59 +1019,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { ty::PredicateKind::ClosureKind(closure_def_id, closure_substs, kind) => { let found_kind = self.closure_kind(closure_substs).unwrap(); - let closure_span = self.tcx.def_span(closure_def_id); - let mut err = struct_span_err!( - self.tcx.sess, - closure_span, - E0525, - "expected a closure that implements the `{}` trait, \ - but this closure only implements `{}`", - kind, - found_kind - ); - - err.span_label( - closure_span, - format!("this closure implements `{}`, not `{}`", found_kind, kind), - ); - err.span_label( - obligation.cause.span, - format!("the requirement to implement `{}` derives from here", kind), - ); - - // Additional context information explaining why the closure only implements - // a particular trait. - if let Some(typeck_results) = &self.typeck_results { - let hir_id = self - .tcx - .hir() - .local_def_id_to_hir_id(closure_def_id.expect_local()); - match (found_kind, typeck_results.closure_kind_origins().get(hir_id)) { - (ty::ClosureKind::FnOnce, Some((span, place))) => { - err.span_label( - *span, - format!( - "closure is `FnOnce` because it moves the \ - variable `{}` out of its environment", - ty::place_to_string_for_capture(tcx, place) - ), - ); - } - (ty::ClosureKind::FnMut, Some((span, place))) => { - err.span_label( - *span, - format!( - "closure is `FnMut` because it mutates the \ - variable `{}` here", - ty::place_to_string_for_capture(tcx, place) - ), - ); - } - _ => {} - } - } - - err + self.report_closure_error(&obligation, closure_def_id, found_kind, kind) } ty::PredicateKind::WellFormed(ty) => { @@ -1266,7 +1037,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { // which bounds actually failed to hold. self.tcx.sess.struct_span_err( span, - &format!("the type `{}` is not well-formed", ty), + format!("the type `{}` is not well-formed", ty), ) } } @@ -1309,7 +1080,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { ty::PredicateKind::Clause(ty::Clause::ConstArgHasType(ct, ty)) => { let mut diag = self.tcx.sess.struct_span_err( span, - &format!("the constant `{}` is not of type `{}`", ct, ty), + format!("the constant `{}` is not of type `{}`", ct, ty), ); self.note_type_err( &mut diag, @@ -1325,121 +1096,29 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { } } - OutputTypeParameterMismatch( + OutputTypeParameterMismatch(box SelectionOutputTypeParameterMismatch { found_trait_ref, expected_trait_ref, - terr @ TypeError::CyclicTy(_), - ) => { - let self_ty = found_trait_ref.self_ty().skip_binder(); - let (cause, terr) = if let ty::Closure(def_id, _) = self_ty.kind() { - ( - ObligationCause::dummy_with_span(tcx.def_span(def_id)), - TypeError::CyclicTy(self_ty), - ) - } else { - (obligation.cause.clone(), terr) - }; - self.report_and_explain_type_error( - TypeTrace::poly_trait_refs(&cause, true, expected_trait_ref, found_trait_ref), - terr, - ) - } - OutputTypeParameterMismatch(found_trait_ref, expected_trait_ref, _) => { - let found_trait_ref = self.resolve_vars_if_possible(found_trait_ref); - let expected_trait_ref = self.resolve_vars_if_possible(expected_trait_ref); - - if expected_trait_ref.self_ty().references_error() { - return; - } - - let Some(found_trait_ty) = found_trait_ref.self_ty().no_bound_vars() else { - return; - }; - - let found_did = match *found_trait_ty.kind() { - ty::Closure(did, _) - | ty::Foreign(did) - | ty::FnDef(did, _) - | ty::Generator(did, ..) => Some(did), - ty::Adt(def, _) => Some(def.did()), - _ => None, - }; - - let found_node = found_did.and_then(|did| self.tcx.hir().get_if_local(did)); - let found_span = found_did.and_then(|did| self.tcx.hir().span_if_local(did)); - - if self.reported_closure_mismatch.borrow().contains(&(span, found_span)) { - // We check closures twice, with obligations flowing in different directions, - // but we want to complain about them only once. - return; - } - - self.reported_closure_mismatch.borrow_mut().insert((span, found_span)); - - let mut not_tupled = false; - - let found = match found_trait_ref.skip_binder().substs.type_at(1).kind() { - ty::Tuple(ref tys) => vec![ArgKind::empty(); tys.len()], - _ => { - not_tupled = true; - vec![ArgKind::empty()] - } - }; - - let expected_ty = expected_trait_ref.skip_binder().substs.type_at(1); - let expected = match expected_ty.kind() { - ty::Tuple(ref tys) => { - tys.iter().map(|t| ArgKind::from_expected_ty(t, Some(span))).collect() - } - _ => { - not_tupled = true; - vec![ArgKind::Arg("_".to_owned(), expected_ty.to_string())] - } - }; - - // If this is a `Fn` family trait and either the expected or found - // is not tupled, then fall back to just a regular mismatch error. - // This shouldn't be common unless manually implementing one of the - // traits manually, but don't make it more confusing when it does - // happen. - if Some(expected_trait_ref.def_id()) != tcx.lang_items().gen_trait() && not_tupled { - self.report_and_explain_type_error( - TypeTrace::poly_trait_refs( - &obligation.cause, - true, - expected_trait_ref, - found_trait_ref, - ), - ty::error::TypeError::Mismatch, - ) - } else if found.len() == expected.len() { - self.report_closure_arg_mismatch( - span, - found_span, - found_trait_ref, - expected_trait_ref, - obligation.cause.code(), - found_node, - obligation.param_env, - ) - } else { - let (closure_span, closure_arg_span, found) = found_did - .and_then(|did| { - let node = self.tcx.hir().get_if_local(did)?; - let (found_span, closure_arg_span, found) = - self.get_fn_like_arguments(node)?; - Some((Some(found_span), closure_arg_span, found)) - }) - .unwrap_or((found_span, None, found)); - - self.report_arg_count_mismatch( - span, - closure_span, - expected, - found, - found_trait_ty.is_closure(), - closure_arg_span, - ) + terr: terr @ TypeError::CyclicTy(_), + }) => self.report_type_parameter_mismatch_cyclic_type_error( + &obligation, + found_trait_ref, + expected_trait_ref, + terr, + ), + OutputTypeParameterMismatch(box SelectionOutputTypeParameterMismatch { + found_trait_ref, + expected_trait_ref, + terr: _, + }) => { + match self.report_type_parameter_mismatch_error( + &obligation, + span, + found_trait_ref, + expected_trait_ref, + ) { + Some(err) => err, + None => return, } } @@ -1454,45 +1133,9 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { ) } SelectionError::NotConstEvaluatable(NotConstEvaluatable::MentionsParam) => { - if !self.tcx.features().generic_const_exprs { - let mut err = self.tcx.sess.struct_span_err( - span, - "constant expression depends on a generic parameter", - ); - // FIXME(const_generics): we should suggest to the user how they can resolve this - // issue. However, this is currently not actually possible - // (see https://github.com/rust-lang/rust/issues/66962#issuecomment-575907083). - // - // Note that with `feature(generic_const_exprs)` this case should not - // be reachable. - err.note("this may fail depending on what value the parameter takes"); - err.emit(); - return; - } - - match obligation.predicate.kind().skip_binder() { - ty::PredicateKind::ConstEvaluatable(ct) => { - let ty::ConstKind::Unevaluated(uv) = ct.kind() else { - bug!("const evaluatable failed for non-unevaluated const `{ct:?}`"); - }; - let mut err = - self.tcx.sess.struct_span_err(span, "unconstrained generic constant"); - let const_span = self.tcx.def_span(uv.def.did); - match self.tcx.sess.source_map().span_to_snippet(const_span) { - Ok(snippet) => err.help(&format!( - "try adding a `where` bound using this expression: `where [(); {}]:`", - snippet - )), - _ => err.help("consider adding a `where` bound using this expression"), - }; - err - } - _ => { - span_bug!( - span, - "unexpected non-ConstEvaluatable predicate, this should not be reachable" - ) - } + match self.report_not_const_evaluatable_error(&obligation, span) { + Some(err) => err, + None => return, } } @@ -1564,6 +1207,14 @@ trait InferCtxtPrivExt<'tcx> { other: bool, ) -> bool; + fn report_similar_impl_candidates_for_root_obligation( + &self, + obligation: &PredicateObligation<'tcx>, + trait_predicate: ty::Binder<'tcx, ty::TraitPredicate<'tcx>>, + body_def_id: LocalDefId, + err: &mut Diagnostic, + ); + /// Gets the parent trait chain start fn get_parent_trait_ref( &self, @@ -1627,13 +1278,86 @@ trait InferCtxtPrivExt<'tcx> { cause_code: &ObligationCauseCode<'tcx>, ) -> bool; + fn get_standard_error_message( + &self, + trait_predicate: &ty::PolyTraitPredicate<'tcx>, + message: Option<String>, + predicate_is_const: bool, + append_const_msg: Option<AppendConstMessage>, + post_message: String, + ) -> String; + fn get_safe_transmute_error_and_reason( &self, - trait_predicate: ty::Binder<'tcx, ty::TraitPredicate<'tcx>>, - obligation: Obligation<'tcx, ty::Predicate<'tcx>>, - trait_ref: ty::Binder<'tcx, ty::TraitRef<'tcx>>, + obligation: PredicateObligation<'tcx>, + trait_ref: ty::PolyTraitRef<'tcx>, span: Span, ) -> (String, Option<String>); + + fn add_tuple_trait_message( + &self, + obligation_cause_code: &ObligationCauseCode<'tcx>, + err: &mut Diagnostic, + ); + + fn try_to_add_help_message( + &self, + obligation: &PredicateObligation<'tcx>, + trait_ref: ty::PolyTraitRef<'tcx>, + trait_predicate: &ty::PolyTraitPredicate<'tcx>, + err: &mut Diagnostic, + span: Span, + is_fn_trait: bool, + suggested: bool, + unsatisfied_const: bool, + ); + + fn add_help_message_for_fn_trait( + &self, + trait_ref: ty::PolyTraitRef<'tcx>, + err: &mut Diagnostic, + implemented_kind: ty::ClosureKind, + params: ty::Binder<'tcx, Ty<'tcx>>, + ); + + fn maybe_add_note_for_unsatisfied_const( + &self, + obligation: &PredicateObligation<'tcx>, + trait_ref: ty::PolyTraitRef<'tcx>, + trait_predicate: &ty::PolyTraitPredicate<'tcx>, + err: &mut Diagnostic, + span: Span, + ) -> UnsatisfiedConst; + + fn report_closure_error( + &self, + obligation: &PredicateObligation<'tcx>, + closure_def_id: DefId, + found_kind: ty::ClosureKind, + kind: ty::ClosureKind, + ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>; + + fn report_type_parameter_mismatch_cyclic_type_error( + &self, + obligation: &PredicateObligation<'tcx>, + found_trait_ref: ty::Binder<'tcx, ty::TraitRef<'tcx>>, + expected_trait_ref: ty::Binder<'tcx, ty::TraitRef<'tcx>>, + terr: TypeError<'tcx>, + ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>; + + fn report_type_parameter_mismatch_error( + &self, + obligation: &PredicateObligation<'tcx>, + span: Span, + found_trait_ref: ty::Binder<'tcx, ty::TraitRef<'tcx>>, + expected_trait_ref: ty::Binder<'tcx, ty::TraitRef<'tcx>>, + ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>>; + + fn report_not_const_evaluatable_error( + &self, + obligation: &PredicateObligation<'tcx>, + span: Span, + ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>>; } impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { @@ -1720,6 +1444,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { | ObligationCauseCode::ExprItemObligation(..) = code { self.note_obligation_cause_code( + error.obligation.cause.body_id, &mut diag, error.obligation.predicate, error.obligation.param_env, @@ -1773,7 +1498,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { .tcx .mk_const( ty::UnevaluatedConst { - def: ty::WithOptConstParam::unknown(data.projection_ty.def_id), + def: data.projection_ty.def_id, substs: data.projection_ty.substs, }, ct.ty(), @@ -1793,7 +1518,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { | ObligationCauseCode::BindingObligation(_, _) | ObligationCauseCode::ExprItemObligation(..) | ObligationCauseCode::ExprBindingObligation(..) - | ObligationCauseCode::ObjectCastObligation(..) + | ObligationCauseCode::Coercion { .. } | ObligationCauseCode::OpaqueType ); @@ -1838,57 +1563,61 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { }); let mut diag = struct_span_err!(self.tcx.sess, obligation.cause.span, E0271, "{msg}"); - let secondary_span = match predicate.kind().skip_binder() { - ty::PredicateKind::Clause(ty::Clause::Projection(proj)) => self - .tcx - .opt_associated_item(proj.projection_ty.def_id) - .and_then(|trait_assoc_item| { - self.tcx - .trait_of_item(proj.projection_ty.def_id) - .map(|id| (trait_assoc_item, id)) - }) - .and_then(|(trait_assoc_item, id)| { - let trait_assoc_ident = trait_assoc_item.ident(self.tcx); - self.tcx.find_map_relevant_impl( - id, - proj.projection_ty.self_ty(), - TreatProjections::ForLookup, - |did| { - self.tcx - .associated_items(did) - .in_definition_order() - .find(|assoc| assoc.ident(self.tcx) == trait_assoc_ident) - }, - ) - }) - .and_then(|item| match self.tcx.hir().get_if_local(item.def_id) { - Some( - hir::Node::TraitItem(hir::TraitItem { - kind: hir::TraitItemKind::Type(_, Some(ty)), - .. - }) - | hir::Node::ImplItem(hir::ImplItem { - kind: hir::ImplItemKind::Type(ty), - .. - }), - ) => Some(( - ty.span, - with_forced_trimmed_paths!(format!( - "type mismatch resolving `{}`", - self.resolve_vars_if_possible(predicate) - .print(FmtPrinter::new_with_limit( - self.tcx, - Namespace::TypeNS, - rustc_session::Limit(5), - )) - .unwrap() - .into_buffer() - )), + let secondary_span = (|| { + let ty::PredicateKind::Clause(ty::Clause::Projection(proj)) = + predicate.kind().skip_binder() + else { + return None; + }; + + let trait_assoc_item = self.tcx.opt_associated_item(proj.projection_ty.def_id)?; + let trait_assoc_ident = trait_assoc_item.ident(self.tcx); + + let mut associated_items = vec![]; + self.tcx.for_each_relevant_impl( + self.tcx.trait_of_item(proj.projection_ty.def_id)?, + proj.projection_ty.self_ty(), + |impl_def_id| { + associated_items.extend( + self.tcx + .associated_items(impl_def_id) + .in_definition_order() + .find(|assoc| assoc.ident(self.tcx) == trait_assoc_ident), + ); + }, + ); + + let [associated_item]: &[ty::AssocItem] = &associated_items[..] else { + return None; + }; + match self.tcx.hir().get_if_local(associated_item.def_id) { + Some( + hir::Node::TraitItem(hir::TraitItem { + kind: hir::TraitItemKind::Type(_, Some(ty)), + .. + }) + | hir::Node::ImplItem(hir::ImplItem { + kind: hir::ImplItemKind::Type(ty), + .. + }), + ) => Some(( + ty.span, + with_forced_trimmed_paths!(format!( + "type mismatch resolving `{}`", + self.resolve_vars_if_possible(predicate) + .print(FmtPrinter::new_with_limit( + self.tcx, + Namespace::TypeNS, + rustc_session::Limit(5), + )) + .unwrap() + .into_buffer() )), - _ => None, - }), - _ => None, - }; + )), + _ => None, + } + })(); + self.note_type_err( &mut diag, &obligation.cause, @@ -1971,13 +1700,14 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { ty::Tuple(..) => Some(10), ty::Param(..) => Some(11), ty::Alias(ty::Projection, ..) => Some(12), - ty::Alias(ty::Opaque, ..) => Some(13), - ty::Never => Some(14), - ty::Adt(..) => Some(15), - ty::Generator(..) => Some(16), - ty::Foreign(..) => Some(17), - ty::GeneratorWitness(..) => Some(18), - ty::GeneratorWitnessMIR(..) => Some(19), + ty::Alias(ty::Inherent, ..) => Some(13), + ty::Alias(ty::Opaque, ..) => Some(14), + ty::Never => Some(15), + ty::Adt(..) => Some(16), + ty::Generator(..) => Some(17), + ty::Foreign(..) => Some(18), + ty::GeneratorWitness(..) => Some(19), + ty::GeneratorWitnessMIR(..) => Some(20), ty::Placeholder(..) | ty::Bound(..) | ty::Infer(..) | ty::Error(_) => None, } } @@ -2058,7 +1788,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { if candidates.iter().any(|c| matches!(c.similarity, CandidateSimilarity::Exact { .. })) { // If any of the candidates is a perfect match, we don't want to show all of them. // This is particularly relevant for the case of numeric types (as they all have the - // same cathegory). + // same category). candidates.retain(|c| matches!(c.similarity, CandidateSimilarity::Exact { .. })); } candidates @@ -2120,7 +1850,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { candidates.sort(); candidates.dedup(); let end = if candidates.len() <= 9 { candidates.len() } else { 8 }; - err.help(&format!( + err.help(format!( "the following {other}types implement trait `{}`:{}{}", trait_ref.print_only_trait_path(), candidates[..end].join(""), @@ -2197,6 +1927,51 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { report(normalized_impl_candidates, err) } + fn report_similar_impl_candidates_for_root_obligation( + &self, + obligation: &PredicateObligation<'tcx>, + trait_predicate: ty::Binder<'tcx, ty::TraitPredicate<'tcx>>, + body_def_id: LocalDefId, + err: &mut Diagnostic, + ) { + // This is *almost* equivalent to + // `obligation.cause.code().peel_derives()`, but it gives us the + // trait predicate for that corresponding root obligation. This + // lets us get a derived obligation from a type parameter, like + // when calling `string.strip_suffix(p)` where `p` is *not* an + // implementer of `Pattern<'_>`. + let mut code = obligation.cause.code(); + let mut trait_pred = trait_predicate; + let mut peeled = false; + while let Some((parent_code, parent_trait_pred)) = code.parent() { + code = parent_code; + if let Some(parent_trait_pred) = parent_trait_pred { + trait_pred = parent_trait_pred; + peeled = true; + } + } + let def_id = trait_pred.def_id(); + // Mention *all* the `impl`s for the *top most* obligation, the + // user might have meant to use one of them, if any found. We skip + // auto-traits or fundamental traits that might not be exactly what + // the user might expect to be presented with. Instead this is + // useful for less general traits. + if peeled + && !self.tcx.trait_is_auto(def_id) + && !self.tcx.lang_items().iter().any(|(_, id)| id == def_id) + { + let trait_ref = trait_pred.to_poly_trait_ref(); + let impl_candidates = self.find_similar_impl_candidates(trait_pred); + self.report_similar_impl_candidates( + &impl_candidates, + trait_ref, + body_def_id, + err, + true, + ); + } + } + /// Gets the parent trait chain start fn get_parent_trait_ref( &self, @@ -2230,14 +2005,18 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { err: &mut Diagnostic, trait_ref: &ty::PolyTraitRef<'tcx>, ) -> bool { - let get_trait_impl = |trait_def_id| { - self.tcx.find_map_relevant_impl( + let get_trait_impls = |trait_def_id| { + let mut trait_impls = vec![]; + self.tcx.for_each_relevant_impl( trait_def_id, trait_ref.skip_binder().self_ty(), - TreatProjections::ForLookup, - Some, - ) + |impl_def_id| { + trait_impls.push(impl_def_id); + }, + ); + trait_impls }; + let required_trait_path = self.tcx.def_path_str(trait_ref.def_id()); let traits_with_same_path: std::collections::BTreeSet<_> = self .tcx @@ -2247,17 +2026,23 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { .collect(); let mut suggested = false; for trait_with_same_path in traits_with_same_path { - if let Some(impl_def_id) = get_trait_impl(trait_with_same_path) { - let impl_span = self.tcx.def_span(impl_def_id); - err.span_help(impl_span, "trait impl with same name found"); - let trait_crate = self.tcx.crate_name(trait_with_same_path.krate); - let crate_msg = format!( - "perhaps two different versions of crate `{}` are being used?", - trait_crate - ); - err.note(&crate_msg); - suggested = true; + let trait_impls = get_trait_impls(trait_with_same_path); + if trait_impls.is_empty() { + continue; } + let impl_spans: Vec<_> = + trait_impls.iter().map(|impl_def_id| self.tcx.def_span(*impl_def_id)).collect(); + err.span_help( + impl_spans, + format!("trait impl{} with same name found", pluralize!(trait_impls.len())), + ); + let trait_crate = self.tcx.crate_name(trait_with_same_path.krate); + let crate_msg = format!( + "perhaps two different versions of crate `{}` are being used?", + trait_crate + ); + err.note(crate_msg); + suggested = true; } suggested } @@ -2388,7 +2173,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { err.cancel(); return; } - err.note(&format!("cannot satisfy `{}`", predicate)); + err.note(format!("cannot satisfy `{}`", predicate)); let impl_candidates = self.find_similar_impl_candidates( predicate.to_opt_poly_trait_pred().unwrap(), ); @@ -2408,7 +2193,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { err.cancel(); return; } - err.note(&format!("cannot satisfy `{}`", predicate)); + err.note(format!("cannot satisfy `{}`", predicate)); } } @@ -2453,9 +2238,9 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { err.cancel(); err = self.tcx.sess.struct_span_err_with_code( span, - &format!( + format!( "cannot {verb} associated {noun} on trait without specifying the corresponding `impl` type", - ), + ), rustc_errors::error_code!(E0790), ); @@ -2562,7 +2347,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { ErrorCode::E0284, true, ); - err.note(&format!("cannot satisfy `{}`", predicate)); + err.note(format!("cannot satisfy `{}`", predicate)); err } else { // If we can't find a substitution, just print a generic error @@ -2573,7 +2358,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { "type annotations needed: cannot satisfy `{}`", predicate, ); - err.span_label(span, &format!("cannot satisfy `{}`", predicate)); + err.span_label(span, format!("cannot satisfy `{}`", predicate)); err } } @@ -2601,7 +2386,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { "type annotations needed: cannot satisfy `{}`", predicate, ); - err.span_label(span, &format!("cannot satisfy `{}`", predicate)); + err.span_label(span, format!("cannot satisfy `{}`", predicate)); err } } @@ -2616,7 +2401,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { "type annotations needed: cannot satisfy `{}`", predicate, ); - err.span_label(span, &format!("cannot satisfy `{}`", predicate)); + err.span_label(span, format!("cannot satisfy `{}`", predicate)); err } }; @@ -2689,13 +2474,13 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { match (spans.len(), crates.len(), crate_names.len()) { (0, 0, 0) => { - err.note(&format!("cannot satisfy `{}`", predicate)); + err.note(format!("cannot satisfy `{}`", predicate)); } (0, _, 1) => { - err.note(&format!("{} in the `{}` crate{}", msg, crates[0], post,)); + err.note(format!("{} in the `{}` crate{}", msg, crates[0], post,)); } (0, _, _) => { - err.note(&format!( + err.note(format!( "{} in the following crates: {}{}", msg, crate_names.join(", "), @@ -2704,19 +2489,17 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { } (_, 0, 0) => { let span: MultiSpan = spans.into(); - err.span_note(span, &msg); + err.span_note(span, msg); } (_, 1, 1) => { let span: MultiSpan = spans.into(); - err.span_note(span, &msg); - err.note( - &format!("and another `impl` found in the `{}` crate{}", crates[0], post,), - ); + err.span_note(span, msg); + err.note(format!("and another `impl` found in the `{}` crate{}", crates[0], post,)); } _ => { let span: MultiSpan = spans.into(); - err.span_note(span, &msg); - err.note(&format!( + err.span_note(span, msg); + err.note(format!( "and more `impl`s found in the following crates: {}{}", crate_names.join(", "), post, @@ -2776,6 +2559,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { // message, and fall back to regular note otherwise. if !self.maybe_note_obligation_cause_for_async_await(err, obligation) { self.note_obligation_cause_code( + obligation.cause.body_id, err, obligation.predicate, obligation.param_env, @@ -2887,7 +2671,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { } err.span_help( multispan, - &format!( + format!( "you could relax the implicit `Sized` bound on `{T}` if it were \ used through indirection like `&{T}` or `Box<{T}>`", T = param.name.ident(), @@ -2919,20 +2703,52 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { false } + fn get_standard_error_message( + &self, + trait_predicate: &ty::PolyTraitPredicate<'tcx>, + message: Option<String>, + predicate_is_const: bool, + append_const_msg: Option<AppendConstMessage>, + post_message: String, + ) -> String { + message + .and_then(|cannot_do_this| { + match (predicate_is_const, append_const_msg) { + // do nothing if predicate is not const + (false, _) => Some(cannot_do_this), + // suggested using default post message + (true, Some(AppendConstMessage::Default)) => { + Some(format!("{cannot_do_this} in const contexts")) + } + // overridden post message + (true, Some(AppendConstMessage::Custom(custom_msg))) => { + Some(format!("{cannot_do_this}{custom_msg}")) + } + // fallback to generic message + (true, None) => None, + } + }) + .unwrap_or_else(|| { + format!("the trait bound `{}` is not satisfied{}", trait_predicate, post_message) + }) + } + fn get_safe_transmute_error_and_reason( &self, - trait_predicate: ty::Binder<'tcx, ty::TraitPredicate<'tcx>>, - obligation: Obligation<'tcx, ty::Predicate<'tcx>>, - trait_ref: ty::Binder<'tcx, ty::TraitRef<'tcx>>, + obligation: PredicateObligation<'tcx>, + trait_ref: ty::PolyTraitRef<'tcx>, span: Span, ) -> (String, Option<String>) { - let src_and_dst = trait_predicate.map_bound(|p| rustc_transmute::Types { - dst: p.trait_ref.substs.type_at(0), - src: p.trait_ref.substs.type_at(1), - }); - let scope = trait_ref.skip_binder().substs.type_at(2); + // Erase regions because layout code doesn't particularly care about regions. + let trait_ref = self.tcx.erase_regions(self.tcx.erase_late_bound_regions(trait_ref)); + + let src_and_dst = rustc_transmute::Types { + dst: trait_ref.substs.type_at(0), + src: trait_ref.substs.type_at(1), + }; + let scope = trait_ref.substs.type_at(2); let Some(assume) = - rustc_transmute::Assume::from_const(self.infcx.tcx, obligation.param_env, trait_ref.skip_binder().substs.const_at(3)) else { + rustc_transmute::Assume::from_const(self.infcx.tcx, obligation.param_env, trait_ref.substs.const_at(3)) else { span_bug!(span, "Unable to construct rustc_transmute::Assume where it was previously possible"); }; match rustc_transmute::TransmuteTypeEnv::new(self.infcx).is_transmutable( @@ -2942,24 +2758,27 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { assume, ) { rustc_transmute::Answer::No(reason) => { - let dst = trait_ref.skip_binder().substs.type_at(0); - let src = trait_ref.skip_binder().substs.type_at(1); - let custom_err_msg = format!("`{src}` cannot be safely transmuted into `{dst}` in the defining scope of `{scope}`").to_string(); + let dst = trait_ref.substs.type_at(0); + let src = trait_ref.substs.type_at(1); + let custom_err_msg = format!( + "`{src}` cannot be safely transmuted into `{dst}` in the defining scope of `{scope}`" + ); let reason_msg = match reason { rustc_transmute::Reason::SrcIsUnspecified => { - format!("`{src}` does not have a well-specified layout").to_string() + format!("`{src}` does not have a well-specified layout") } + rustc_transmute::Reason::DstIsUnspecified => { - format!("`{dst}` does not have a well-specified layout").to_string() + format!("`{dst}` does not have a well-specified layout") } + rustc_transmute::Reason::DstIsBitIncompatible => { format!("At least one value of `{src}` isn't a bit-valid value of `{dst}`") - .to_string() } + rustc_transmute::Reason::DstIsPrivate => format!( "`{dst}` is or contains a type or field that is not visible in that scope" - ) - .to_string(), + ), // FIXME(bryangarza): Include the number of bytes of src and dst rustc_transmute::Reason::DstIsTooBig => { format!("The size of `{src}` is smaller than the size of `{dst}`") @@ -2975,8 +2794,449 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { _ => span_bug!(span, "Unsupported rustc_transmute::Reason variant"), } } + + fn add_tuple_trait_message( + &self, + obligation_cause_code: &ObligationCauseCode<'tcx>, + err: &mut Diagnostic, + ) { + match obligation_cause_code { + ObligationCauseCode::RustCall => { + err.set_primary_message("functions with the \"rust-call\" ABI must take a single non-self tuple argument"); + } + ObligationCauseCode::BindingObligation(def_id, _) + | ObligationCauseCode::ItemObligation(def_id) + if self.tcx.is_fn_trait(*def_id) => + { + err.code(rustc_errors::error_code!(E0059)); + err.set_primary_message(format!( + "type parameter to bare `{}` trait must be a tuple", + self.tcx.def_path_str(*def_id) + )); + } + _ => {} + } + } + + fn try_to_add_help_message( + &self, + obligation: &PredicateObligation<'tcx>, + trait_ref: ty::PolyTraitRef<'tcx>, + trait_predicate: &ty::PolyTraitPredicate<'tcx>, + err: &mut Diagnostic, + span: Span, + is_fn_trait: bool, + suggested: bool, + unsatisfied_const: bool, + ) { + let body_def_id = obligation.cause.body_id; + // Try to report a help message + if is_fn_trait + && let Ok((implemented_kind, params)) = self.type_implements_fn_trait( + obligation.param_env, + trait_ref.self_ty(), + trait_predicate.skip_binder().constness, + trait_predicate.skip_binder().polarity, + ) + { + self.add_help_message_for_fn_trait(trait_ref, err, implemented_kind, params); + } else if !trait_ref.has_non_region_infer() + && self.predicate_can_apply(obligation.param_env, *trait_predicate) + { + // If a where-clause may be useful, remind the + // user that they can add it. + // + // don't display an on-unimplemented note, as + // these notes will often be of the form + // "the type `T` can't be frobnicated" + // which is somewhat confusing. + self.suggest_restricting_param_bound( + err, + *trait_predicate, + None, + obligation.cause.body_id, + ); + } else if !suggested && !unsatisfied_const { + // Can't show anything else useful, try to find similar impls. + let impl_candidates = self.find_similar_impl_candidates(*trait_predicate); + if !self.report_similar_impl_candidates( + &impl_candidates, + trait_ref, + body_def_id, + err, + true, + ) { + self.report_similar_impl_candidates_for_root_obligation(&obligation, *trait_predicate, body_def_id, err); + } + + self.maybe_suggest_convert_to_slice( + err, + trait_ref, + impl_candidates.as_slice(), + span, + ); + } + } + + fn add_help_message_for_fn_trait( + &self, + trait_ref: ty::PolyTraitRef<'tcx>, + err: &mut Diagnostic, + implemented_kind: ty::ClosureKind, + params: ty::Binder<'tcx, Ty<'tcx>>, + ) { + // If the type implements `Fn`, `FnMut`, or `FnOnce`, suppress the following + // suggestion to add trait bounds for the type, since we only typically implement + // these traits once. + + // Note if the `FnMut` or `FnOnce` is less general than the trait we're trying + // to implement. + let selected_kind = self + .tcx + .fn_trait_kind_from_def_id(trait_ref.def_id()) + .expect("expected to map DefId to ClosureKind"); + if !implemented_kind.extends(selected_kind) { + err.note(format!( + "`{}` implements `{}`, but it must implement `{}`, which is more general", + trait_ref.skip_binder().self_ty(), + implemented_kind, + selected_kind + )); + } + + // Note any argument mismatches + let given_ty = params.skip_binder(); + let expected_ty = trait_ref.skip_binder().substs.type_at(1); + if let ty::Tuple(given) = given_ty.kind() + && let ty::Tuple(expected) = expected_ty.kind() + { + if expected.len() != given.len() { + // Note number of types that were expected and given + err.note( + format!( + "expected a closure taking {} argument{}, but one taking {} argument{} was given", + given.len(), + pluralize!(given.len()), + expected.len(), + pluralize!(expected.len()), + ) + ); + } else if !self.same_type_modulo_infer(given_ty, expected_ty) { + // Print type mismatch + let (expected_args, given_args) = + self.cmp(given_ty, expected_ty); + err.note_expected_found( + &"a closure with arguments", + expected_args, + &"a closure with arguments", + given_args, + ); + } + } + } + + fn maybe_add_note_for_unsatisfied_const( + &self, + obligation: &PredicateObligation<'tcx>, + trait_ref: ty::PolyTraitRef<'tcx>, + trait_predicate: &ty::PolyTraitPredicate<'tcx>, + err: &mut Diagnostic, + span: Span, + ) -> UnsatisfiedConst { + let mut unsatisfied_const = UnsatisfiedConst(false); + if trait_predicate.is_const_if_const() && obligation.param_env.is_const() { + let non_const_predicate = trait_ref.without_const(); + let non_const_obligation = Obligation { + cause: obligation.cause.clone(), + param_env: obligation.param_env.without_const(), + predicate: non_const_predicate.to_predicate(self.tcx), + recursion_depth: obligation.recursion_depth, + }; + if self.predicate_may_hold(&non_const_obligation) { + unsatisfied_const = UnsatisfiedConst(true); + err.span_note( + span, + format!( + "the trait `{}` is implemented for `{}`, \ + but that implementation is not `const`", + non_const_predicate.print_modifiers_and_trait_path(), + trait_ref.skip_binder().self_ty(), + ), + ); + } + } + unsatisfied_const + } + + fn report_closure_error( + &self, + obligation: &PredicateObligation<'tcx>, + closure_def_id: DefId, + found_kind: ty::ClosureKind, + kind: ty::ClosureKind, + ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> { + let closure_span = self.tcx.def_span(closure_def_id); + let mut err = struct_span_err!( + self.tcx.sess, + closure_span, + E0525, + "expected a closure that implements the `{}` trait, \ + but this closure only implements `{}`", + kind, + found_kind + ); + + err.span_label( + closure_span, + format!("this closure implements `{}`, not `{}`", found_kind, kind), + ); + err.span_label( + obligation.cause.span, + format!("the requirement to implement `{}` derives from here", kind), + ); + + // Additional context information explaining why the closure only implements + // a particular trait. + if let Some(typeck_results) = &self.typeck_results { + let hir_id = self.tcx.hir().local_def_id_to_hir_id(closure_def_id.expect_local()); + match (found_kind, typeck_results.closure_kind_origins().get(hir_id)) { + (ty::ClosureKind::FnOnce, Some((span, place))) => { + err.span_label( + *span, + format!( + "closure is `FnOnce` because it moves the \ + variable `{}` out of its environment", + ty::place_to_string_for_capture(self.tcx, place) + ), + ); + } + (ty::ClosureKind::FnMut, Some((span, place))) => { + err.span_label( + *span, + format!( + "closure is `FnMut` because it mutates the \ + variable `{}` here", + ty::place_to_string_for_capture(self.tcx, place) + ), + ); + } + _ => {} + } + } + + err + } + + fn report_type_parameter_mismatch_cyclic_type_error( + &self, + obligation: &PredicateObligation<'tcx>, + found_trait_ref: ty::Binder<'tcx, ty::TraitRef<'tcx>>, + expected_trait_ref: ty::Binder<'tcx, ty::TraitRef<'tcx>>, + terr: TypeError<'tcx>, + ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> { + let self_ty = found_trait_ref.self_ty().skip_binder(); + let (cause, terr) = if let ty::Closure(def_id, _) = self_ty.kind() { + ( + ObligationCause::dummy_with_span(self.tcx.def_span(def_id)), + TypeError::CyclicTy(self_ty), + ) + } else { + (obligation.cause.clone(), terr) + }; + self.report_and_explain_type_error( + TypeTrace::poly_trait_refs(&cause, true, expected_trait_ref, found_trait_ref), + terr, + ) + } + + fn report_type_parameter_mismatch_error( + &self, + obligation: &PredicateObligation<'tcx>, + span: Span, + found_trait_ref: ty::Binder<'tcx, ty::TraitRef<'tcx>>, + expected_trait_ref: ty::Binder<'tcx, ty::TraitRef<'tcx>>, + ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> { + let found_trait_ref = self.resolve_vars_if_possible(found_trait_ref); + let expected_trait_ref = self.resolve_vars_if_possible(expected_trait_ref); + + if expected_trait_ref.self_ty().references_error() { + return None; + } + + let Some(found_trait_ty) = found_trait_ref.self_ty().no_bound_vars() else { + return None; + }; + + let found_did = match *found_trait_ty.kind() { + ty::Closure(did, _) | ty::Foreign(did) | ty::FnDef(did, _) | ty::Generator(did, ..) => { + Some(did) + } + ty::Adt(def, _) => Some(def.did()), + _ => None, + }; + + let found_node = found_did.and_then(|did| self.tcx.hir().get_if_local(did)); + let found_span = found_did.and_then(|did| self.tcx.hir().span_if_local(did)); + + if self.reported_closure_mismatch.borrow().contains(&(span, found_span)) { + // We check closures twice, with obligations flowing in different directions, + // but we want to complain about them only once. + return None; + } + + self.reported_closure_mismatch.borrow_mut().insert((span, found_span)); + + let mut not_tupled = false; + + let found = match found_trait_ref.skip_binder().substs.type_at(1).kind() { + ty::Tuple(ref tys) => vec![ArgKind::empty(); tys.len()], + _ => { + not_tupled = true; + vec![ArgKind::empty()] + } + }; + + let expected_ty = expected_trait_ref.skip_binder().substs.type_at(1); + let expected = match expected_ty.kind() { + ty::Tuple(ref tys) => { + tys.iter().map(|t| ArgKind::from_expected_ty(t, Some(span))).collect() + } + _ => { + not_tupled = true; + vec![ArgKind::Arg("_".to_owned(), expected_ty.to_string())] + } + }; + + // If this is a `Fn` family trait and either the expected or found + // is not tupled, then fall back to just a regular mismatch error. + // This shouldn't be common unless manually implementing one of the + // traits manually, but don't make it more confusing when it does + // happen. + Some( + if Some(expected_trait_ref.def_id()) != self.tcx.lang_items().gen_trait() && not_tupled + { + self.report_and_explain_type_error( + TypeTrace::poly_trait_refs( + &obligation.cause, + true, + expected_trait_ref, + found_trait_ref, + ), + ty::error::TypeError::Mismatch, + ) + } else if found.len() == expected.len() { + self.report_closure_arg_mismatch( + span, + found_span, + found_trait_ref, + expected_trait_ref, + obligation.cause.code(), + found_node, + obligation.param_env, + ) + } else { + let (closure_span, closure_arg_span, found) = found_did + .and_then(|did| { + let node = self.tcx.hir().get_if_local(did)?; + let (found_span, closure_arg_span, found) = + self.get_fn_like_arguments(node)?; + Some((Some(found_span), closure_arg_span, found)) + }) + .unwrap_or((found_span, None, found)); + + self.report_arg_count_mismatch( + span, + closure_span, + expected, + found, + found_trait_ty.is_closure(), + closure_arg_span, + ) + }, + ) + } + + fn report_not_const_evaluatable_error( + &self, + obligation: &PredicateObligation<'tcx>, + span: Span, + ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> { + if !self.tcx.features().generic_const_exprs { + let mut err = self + .tcx + .sess + .struct_span_err(span, "constant expression depends on a generic parameter"); + // FIXME(const_generics): we should suggest to the user how they can resolve this + // issue. However, this is currently not actually possible + // (see https://github.com/rust-lang/rust/issues/66962#issuecomment-575907083). + // + // Note that with `feature(generic_const_exprs)` this case should not + // be reachable. + err.note("this may fail depending on what value the parameter takes"); + err.emit(); + return None; + } + + match obligation.predicate.kind().skip_binder() { + ty::PredicateKind::ConstEvaluatable(ct) => { + let ty::ConstKind::Unevaluated(uv) = ct.kind() else { + bug!("const evaluatable failed for non-unevaluated const `{ct:?}`"); + }; + let mut err = self.tcx.sess.struct_span_err(span, "unconstrained generic constant"); + let const_span = self.tcx.def_span(uv.def); + match self.tcx.sess.source_map().span_to_snippet(const_span) { + Ok(snippet) => err.help(format!( + "try adding a `where` bound using this expression: `where [(); {}]:`", + snippet + )), + _ => err.help("consider adding a `where` bound using this expression"), + }; + Some(err) + } + _ => { + span_bug!( + span, + "unexpected non-ConstEvaluatable predicate, this should not be reachable" + ) + } + } + } } +struct UnsatisfiedConst(pub bool); + +fn get_explanation_based_on_obligation<'tcx>( + obligation: &PredicateObligation<'tcx>, + trait_ref: ty::PolyTraitRef<'tcx>, + trait_predicate: &ty::PolyTraitPredicate<'tcx>, + pre_message: String, +) -> String { + if let ObligationCauseCode::MainFunctionType = obligation.cause.code() { + "consider using `()`, or a `Result`".to_owned() + } else { + let ty_desc = match trait_ref.skip_binder().self_ty().kind() { + ty::FnDef(_, _) => Some("fn item"), + ty::Closure(_, _) => Some("closure"), + _ => None, + }; + + match ty_desc { + Some(desc) => format!( + "{}the trait `{}` is not implemented for {} `{}`", + pre_message, + trait_predicate.print_modifiers_and_trait_path(), + desc, + trait_ref.skip_binder().self_ty(), + ), + None => format!( + "{}the trait `{}` is not implemented for `{}`", + pre_message, + trait_predicate.print_modifiers_and_trait_path(), + trait_ref.skip_binder().self_ty(), + ), + } + } +} /// Crude way of getting back an `Expr` from a `Span`. pub struct FindExprBySpan<'hir> { pub span: Span, diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs index a9c4e1268..10bd027b6 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs @@ -306,6 +306,14 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { } } } + + // `&[{integral}]` - `FromIterator` needs that. + if let ty::Ref(_, ref_ty, rustc_ast::Mutability::Not) = self_ty.kind() + && let ty::Slice(sty) = ref_ty.kind() + && sty.is_integral() + { + flags.push((sym::_Self, Some("&[{integral}]".to_owned()))); + } }); if let Ok(Some(command)) = OnUnimplementedDirective::of_item(self.tcx, def_id) { @@ -327,7 +335,7 @@ pub struct OnUnimplementedDirective { pub label: Option<OnUnimplementedFormatString>, pub note: Option<OnUnimplementedFormatString>, pub parent_label: Option<OnUnimplementedFormatString>, - pub append_const_msg: Option<Option<Symbol>>, + pub append_const_msg: Option<AppendConstMessage>, } /// For the `#[rustc_on_unimplemented]` attribute @@ -337,11 +345,21 @@ pub struct OnUnimplementedNote { pub label: Option<String>, pub note: Option<String>, pub parent_label: Option<String>, - /// Append a message for `~const Trait` errors. `None` means not requested and - /// should fallback to a generic message, `Some(None)` suggests using the default - /// appended message, `Some(Some(s))` suggests use the `s` message instead of the - /// default one.. - pub append_const_msg: Option<Option<Symbol>>, + // If none, should fall back to a generic message + pub append_const_msg: Option<AppendConstMessage>, +} + +/// Append a message for `~const Trait` errors. +#[derive(Clone, Copy, PartialEq, Eq, Debug)] +pub enum AppendConstMessage { + Default, + Custom(Symbol), +} + +impl Default for AppendConstMessage { + fn default() -> Self { + AppendConstMessage::Default + } } impl<'tcx> OnUnimplementedDirective { @@ -419,10 +437,10 @@ impl<'tcx> OnUnimplementedDirective { } } else if item.has_name(sym::append_const_msg) && append_const_msg.is_none() { if let Some(msg) = item.value_str() { - append_const_msg = Some(Some(msg)); + append_const_msg = Some(AppendConstMessage::Custom(msg)); continue; } else if item.is_word() { - append_const_msg = Some(None); + append_const_msg = Some(AppendConstMessage::Default); continue; } } diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs index fb75ec767..82bad96ea 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs @@ -25,23 +25,22 @@ use rustc_hir::{AsyncGeneratorKind, GeneratorKind, Node}; use rustc_hir::{Expr, HirId}; use rustc_infer::infer::error_reporting::TypeErrCtxt; use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind}; -use rustc_infer::infer::{InferOk, LateBoundRegionConversionTime}; +use rustc_infer::infer::{DefineOpaqueTypes, InferOk, LateBoundRegionConversionTime}; use rustc_middle::hir::map; use rustc_middle::ty::error::TypeError::{self, Sorts}; -use rustc_middle::ty::relate::TypeRelation; use rustc_middle::ty::{ self, suggest_arbitrary_trait_bound, suggest_constraining_type_param, AdtKind, - GeneratorDiagnosticData, GeneratorInteriorTypeCause, Infer, InferTy, InternalSubsts, - IsSuggestable, ToPredicate, Ty, TyCtxt, TypeAndMut, TypeFoldable, TypeFolder, - TypeSuperFoldable, TypeVisitableExt, TypeckResults, + GeneratorDiagnosticData, GeneratorInteriorTypeCause, InferTy, InternalSubsts, IsSuggestable, + ToPredicate, Ty, TyCtxt, TypeAndMut, TypeFoldable, TypeFolder, TypeSuperFoldable, + TypeVisitableExt, TypeckResults, }; use rustc_span::def_id::LocalDefId; use rustc_span::symbol::{sym, Ident, Symbol}; use rustc_span::{BytePos, DesugaringKind, ExpnKind, MacroKind, Span, DUMMY_SP}; use rustc_target::spec::abi; +use std::iter; use std::ops::Deref; -use super::method_chain::CollectAllMismatches; use super::InferCtxtPrivExt; use crate::infer::InferCtxtExt as _; use crate::traits::query::evaluate_obligation::InferCtxtExt as _; @@ -262,7 +261,6 @@ pub trait TypeErrCtxtExt<'tcx> { fn suggest_impl_trait( &self, err: &mut Diagnostic, - span: Span, obligation: &PredicateObligation<'tcx>, trait_pred: ty::PolyTraitPredicate<'tcx>, ) -> bool; @@ -319,6 +317,7 @@ pub trait TypeErrCtxtExt<'tcx> { fn note_obligation_cause_code<T>( &self, + body_id: LocalDefId, err: &mut Diagnostic, predicate: T, param_env: ty::ParamEnv<'tcx>, @@ -359,8 +358,9 @@ pub trait TypeErrCtxtExt<'tcx> { ); fn note_function_argument_obligation( &self, - arg_hir_id: HirId, + body_id: LocalDefId, err: &mut Diagnostic, + arg_hir_id: HirId, parent_code: &ObligationCauseCode<'tcx>, param_env: ty::ParamEnv<'tcx>, predicate: ty::Predicate<'tcx>, @@ -386,7 +386,7 @@ pub trait TypeErrCtxtExt<'tcx> { fn maybe_suggest_convert_to_slice( &self, err: &mut Diagnostic, - trait_ref: ty::Binder<'tcx, ty::TraitRef<'tcx>>, + trait_ref: ty::PolyTraitRef<'tcx>, candidate_impls: &[ImplCandidate<'tcx>], span: Span, ); @@ -420,7 +420,7 @@ fn suggest_restriction<'tcx>( ) { if hir_generics.where_clause_span.from_expansion() || hir_generics.where_clause_span.desugaring_kind().is_some() - || projection.map_or(false, |projection| tcx.opt_rpitit_info(projection.def_id).is_some()) + || projection.is_some_and(|projection| tcx.opt_rpitit_info(projection.def_id).is_some()) { return; } @@ -515,7 +515,7 @@ fn suggest_restriction<'tcx>( err.span_suggestion_verbose( sp, - &format!("consider further restricting {}", msg), + format!("consider further restricting {}", msg), suggestion, Applicability::MachineApplicable, ); @@ -530,6 +530,10 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { associated_ty: Option<(&'static str, Ty<'tcx>)>, mut body_id: LocalDefId, ) { + if trait_pred.skip_binder().polarity == ty::ImplPolarity::Negative { + return; + } + let trait_pred = self.resolve_numeric_literals_with_default(trait_pred); let self_ty = trait_pred.skip_binder().self_ty(); @@ -964,7 +968,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { // a more general note. err.span_suggestion_verbose( obligation.cause.span.shrink_to_hi(), - &msg, + msg, format!("({args})"), Applicability::HasPlaceholders, ); @@ -994,7 +998,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { } _ => return false, }; - err.help(&format!("{msg}: `{name}({args})`")); + err.help(format!("{msg}: `{name}({args})`")); } true } @@ -1334,7 +1338,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { let msg = format!("the trait bound `{}` is not satisfied", old_pred); if has_custom_message { - err.note(&msg); + err.note(msg); } else { err.message = vec![(rustc_errors::DiagnosticMessage::Str(msg), Style::NoStyle)]; @@ -1358,7 +1362,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { } else { let is_mut = mut_ref_self_ty_satisfies_pred || ref_inner_ty_mut; let sugg_prefix = format!("&{}", if is_mut { "mut " } else { "" }); - let sugg_msg = &format!( + let sugg_msg = format!( "consider{} borrowing here", if is_mut { " mutably" } else { "" } ); @@ -1381,7 +1385,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { } } - // Issue #104961, we need to add parentheses properly for compond expressions + // Issue #104961, we need to add parentheses properly for compound expressions // for example, `x.starts_with("hi".to_string() + "you")` // should be `x.starts_with(&("hi".to_string() + "you"))` let Some(body_id) = self.tcx.hir().maybe_body_owned_by(obligation.cause.body_id) else { return false; }; @@ -1437,8 +1441,9 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { err: &mut Diagnostic, obligation: &PredicateObligation<'tcx>, self_ty: Ty<'tcx>, - object_ty: Ty<'tcx>, + target_ty: Ty<'tcx>, ) { + let ty::Ref(_, object_ty, hir::Mutability::Not) = target_ty.kind() else { return; }; let ty::Dynamic(predicates, _, ty::Dyn) = object_ty.kind() else { return; }; let self_ref_ty = self.tcx.mk_imm_ref(self.tcx.lifetimes.re_erased, self_ty); @@ -1452,8 +1457,8 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { err.span_suggestion( obligation.cause.span.shrink_to_lo(), - &format!( - "consider borrowing the value, since `&{self_ty}` can be coerced into `{object_ty}`" + format!( + "consider borrowing the value, since `&{self_ty}` can be coerced into `{target_ty}`" ), "&", Applicability::MaybeIncorrect, @@ -1505,7 +1510,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { }; err.multipart_suggestion_verbose( - &msg, + msg, suggestions, Applicability::MachineApplicable, ); @@ -1583,55 +1588,68 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { } fn suggest_remove_await(&self, obligation: &PredicateObligation<'tcx>, err: &mut Diagnostic) { - let span = obligation.cause.span; - - if let ObligationCauseCode::AwaitableExpr(hir_id) = obligation.cause.code().peel_derives() { - let hir = self.tcx.hir(); - if let Some(hir::Node::Expr(expr)) = hir_id.and_then(|hir_id| hir.find(hir_id)) { - // FIXME: use `obligation.predicate.kind()...trait_ref.self_ty()` to see if we have `()` - // and if not maybe suggest doing something else? If we kept the expression around we - // could also check if it is an fn call (very likely) and suggest changing *that*, if - // it is from the local crate. + let hir = self.tcx.hir(); + if let ObligationCauseCode::AwaitableExpr(Some(hir_id)) = obligation.cause.code().peel_derives() + && let hir::Node::Expr(expr) = hir.get(*hir_id) + { + // FIXME: use `obligation.predicate.kind()...trait_ref.self_ty()` to see if we have `()` + // and if not maybe suggest doing something else? If we kept the expression around we + // could also check if it is an fn call (very likely) and suggest changing *that*, if + // it is from the local crate. + + // use nth(1) to skip one layer of desugaring from `IntoIter::into_iter` + if let Some((_, hir::Node::Expr(await_expr))) = hir.parent_iter(*hir_id).nth(1) + && let Some(expr_span) = expr.span.find_ancestor_inside(await_expr.span) + { + let removal_span = self.tcx + .sess + .source_map() + .span_extend_while(expr_span, char::is_whitespace) + .unwrap_or(expr_span) + .shrink_to_hi() + .to(await_expr.span.shrink_to_hi()); err.span_suggestion( - span, + removal_span, "remove the `.await`", "", Applicability::MachineApplicable, ); - // FIXME: account for associated `async fn`s. - if let hir::Expr { span, kind: hir::ExprKind::Call(base, _), .. } = expr { - if let ty::PredicateKind::Clause(ty::Clause::Trait(pred)) = - obligation.predicate.kind().skip_binder() + } else { + err.span_label(obligation.cause.span, "remove the `.await`"); + } + // FIXME: account for associated `async fn`s. + if let hir::Expr { span, kind: hir::ExprKind::Call(base, _), .. } = expr { + if let ty::PredicateKind::Clause(ty::Clause::Trait(pred)) = + obligation.predicate.kind().skip_binder() + { + err.span_label(*span, format!("this call returns `{}`", pred.self_ty())); + } + if let Some(typeck_results) = &self.typeck_results + && let ty = typeck_results.expr_ty_adjusted(base) + && let ty::FnDef(def_id, _substs) = ty.kind() + && let Some(hir::Node::Item(hir::Item { ident, span, vis_span, .. })) = + hir.get_if_local(*def_id) { - err.span_label(*span, &format!("this call returns `{}`", pred.self_ty())); - } - if let Some(typeck_results) = &self.typeck_results - && let ty = typeck_results.expr_ty_adjusted(base) - && let ty::FnDef(def_id, _substs) = ty.kind() - && let Some(hir::Node::Item(hir::Item { ident, span, vis_span, .. })) = - hir.get_if_local(*def_id) - { - let msg = format!( - "alternatively, consider making `fn {}` asynchronous", - ident + let msg = format!( + "alternatively, consider making `fn {}` asynchronous", + ident + ); + if vis_span.is_empty() { + err.span_suggestion_verbose( + span.shrink_to_lo(), + msg, + "async ", + Applicability::MaybeIncorrect, + ); + } else { + err.span_suggestion_verbose( + vis_span.shrink_to_hi(), + msg, + " async", + Applicability::MaybeIncorrect, ); - if vis_span.is_empty() { - err.span_suggestion_verbose( - span.shrink_to_lo(), - &msg, - "async ", - Applicability::MaybeIncorrect, - ); - } else { - err.span_suggestion_verbose( - vis_span.shrink_to_hi(), - &msg, - " async", - Applicability::MaybeIncorrect, - ); - } } - } + } } } } @@ -1704,7 +1722,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { Applicability::MachineApplicable, ); } else { - err.note(&format!( + err.note(format!( "`{}` is implemented for `{:?}`, but not for `{:?}`", trait_pred.print_modifiers_and_trait_path(), suggested_ty, @@ -1741,7 +1759,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { { err.span_label( expr.span, - &format!( + format!( "this expression has type `{}`, which implements `{}`", ty, trait_pred.print_modifiers_and_trait_path() @@ -1773,215 +1791,66 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { fn suggest_impl_trait( &self, err: &mut Diagnostic, - span: Span, obligation: &PredicateObligation<'tcx>, trait_pred: ty::PolyTraitPredicate<'tcx>, ) -> bool { - match obligation.cause.code().peel_derives() { - // Only suggest `impl Trait` if the return type is unsized because it is `dyn Trait`. - ObligationCauseCode::SizedReturnType => {} - _ => return false, - } - - let hir = self.tcx.hir(); - let fn_hir_id = hir.local_def_id_to_hir_id(obligation.cause.body_id); - let node = hir.find_by_def_id(obligation.cause.body_id); - let Some(hir::Node::Item(hir::Item { - kind: hir::ItemKind::Fn(sig, _, body_id), - .. - })) = node - else { + let ObligationCauseCode::SizedReturnType = obligation.cause.code() else { return false; }; - let body = hir.body(*body_id); - let trait_pred = self.resolve_vars_if_possible(trait_pred); - let ty = trait_pred.skip_binder().self_ty(); - let is_object_safe = match ty.kind() { - ty::Dynamic(predicates, _, ty::Dyn) => { - // If the `dyn Trait` is not object safe, do not suggest `Box<dyn Trait>`. - predicates - .principal_def_id() - .map_or(true, |def_id| self.tcx.check_is_object_safe(def_id)) - } - // We only want to suggest `impl Trait` to `dyn Trait`s. - // For example, `fn foo() -> str` needs to be filtered out. - _ => return false, - }; - - let hir::FnRetTy::Return(ret_ty) = sig.decl.output else { + let ty::Dynamic(_, _, ty::Dyn) = trait_pred.self_ty().skip_binder().kind() else { return false; }; - // Use `TypeVisitor` instead of the output type directly to find the span of `ty` for - // cases like `fn foo() -> (dyn Trait, i32) {}`. - // Recursively look for `TraitObject` types and if there's only one, use that span to - // suggest `impl Trait`. - - // Visit to make sure there's a single `return` type to suggest `impl Trait`, - // otherwise suggest using `Box<dyn Trait>` or an enum. - let mut visitor = ReturnsVisitor::default(); - visitor.visit_body(&body); - - let typeck_results = self.typeck_results.as_ref().unwrap(); - let Some(liberated_sig) = typeck_results.liberated_fn_sigs().get(fn_hir_id).copied() else { return false; }; - - let ret_types = visitor - .returns - .iter() - .filter_map(|expr| Some((expr.span, typeck_results.node_type_opt(expr.hir_id)?))) - .map(|(expr_span, ty)| (expr_span, self.resolve_vars_if_possible(ty))); - let (last_ty, all_returns_have_same_type, only_never_return) = ret_types.clone().fold( - (None, true, true), - |(last_ty, mut same, only_never_return): (std::option::Option<Ty<'_>>, bool, bool), - (_, ty)| { - let ty = self.resolve_vars_if_possible(ty); - same &= - !matches!(ty.kind(), ty::Error(_)) - && last_ty.map_or(true, |last_ty| { - // FIXME: ideally we would use `can_coerce` here instead, but `typeck` comes - // *after* in the dependency graph. - match (ty.kind(), last_ty.kind()) { - (Infer(InferTy::IntVar(_)), Infer(InferTy::IntVar(_))) - | (Infer(InferTy::FloatVar(_)), Infer(InferTy::FloatVar(_))) - | (Infer(InferTy::FreshIntTy(_)), Infer(InferTy::FreshIntTy(_))) - | ( - Infer(InferTy::FreshFloatTy(_)), - Infer(InferTy::FreshFloatTy(_)), - ) => true, - _ => ty == last_ty, - } - }); - (Some(ty), same, only_never_return && matches!(ty.kind(), ty::Never)) - }, - ); - let mut spans_and_needs_box = vec![]; - - match liberated_sig.output().kind() { - ty::Dynamic(predicates, _, ty::Dyn) => { - let cause = ObligationCause::misc(ret_ty.span, obligation.cause.body_id); - let param_env = ty::ParamEnv::empty(); - - if !only_never_return { - for (expr_span, return_ty) in ret_types { - let self_ty_satisfies_dyn_predicates = |self_ty| { - predicates.iter().all(|predicate| { - let pred = predicate.with_self_ty(self.tcx, self_ty); - let obl = Obligation::new(self.tcx, cause.clone(), param_env, pred); - self.predicate_may_hold(&obl) - }) - }; - - if let ty::Adt(def, substs) = return_ty.kind() - && def.is_box() - && self_ty_satisfies_dyn_predicates(substs.type_at(0)) - { - spans_and_needs_box.push((expr_span, false)); - } else if self_ty_satisfies_dyn_predicates(return_ty) { - spans_and_needs_box.push((expr_span, true)); - } else { - return false; - } - } - } - } - _ => return false, - }; - - let sm = self.tcx.sess.source_map(); - if !ret_ty.span.overlaps(span) { - return false; - } - let snippet = if let hir::TyKind::TraitObject(..) = ret_ty.kind { - if let Ok(snippet) = sm.span_to_snippet(ret_ty.span) { - snippet - } else { - return false; - } - } else { - // Substitute the type, so we can print a fixup given `type Alias = dyn Trait` - let name = liberated_sig.output().to_string(); - let name = - name.strip_prefix('(').and_then(|name| name.strip_suffix(')')).unwrap_or(&name); - if !name.starts_with("dyn ") { - return false; - } - name.to_owned() - }; - err.code(error_code!(E0746)); err.set_primary_message("return type cannot have an unboxed trait object"); err.children.clear(); - let impl_trait_msg = "for information on `impl Trait`, see \ - <https://doc.rust-lang.org/book/ch10-02-traits.html\ - #returning-types-that-implement-traits>"; - let trait_obj_msg = "for information on trait objects, see \ - <https://doc.rust-lang.org/book/ch17-02-trait-objects.html\ - #using-trait-objects-that-allow-for-values-of-different-types>"; - - let has_dyn = snippet.split_whitespace().next().map_or(false, |s| s == "dyn"); - let trait_obj = if has_dyn { &snippet[4..] } else { &snippet }; - if only_never_return { - // No return paths, probably using `panic!()` or similar. - // Suggest `-> impl Trait`, and if `Trait` is object safe, `-> Box<dyn Trait>`. - suggest_trait_object_return_type_alternatives( - err, - ret_ty.span, - trait_obj, - is_object_safe, - ); - } else if let (Some(last_ty), true) = (last_ty, all_returns_have_same_type) { - // Suggest `-> impl Trait`. + + let span = obligation.cause.span; + if let Ok(snip) = self.tcx.sess.source_map().span_to_snippet(span) + && snip.starts_with("dyn ") + { err.span_suggestion( - ret_ty.span, - &format!( - "use `impl {1}` as the return type, as all return paths are of type `{}`, \ - which implements `{1}`", - last_ty, trait_obj, - ), - format!("impl {}", trait_obj), - Applicability::MachineApplicable, + span.with_hi(span.lo() + BytePos(4)), + "return an `impl Trait` instead of a `dyn Trait`, \ + if all returned values are the same type", + "impl ", + Applicability::MaybeIncorrect, ); - err.note(impl_trait_msg); - } else { - if is_object_safe { - // Suggest `-> Box<dyn Trait>` and `Box::new(returned_value)`. - err.multipart_suggestion( - "return a boxed trait object instead", - vec![ - (ret_ty.span.shrink_to_lo(), "Box<".to_string()), - (span.shrink_to_hi(), ">".to_string()), - ], - Applicability::MaybeIncorrect, - ); - for (span, needs_box) in spans_and_needs_box { - if needs_box { - err.multipart_suggestion( - "... and box this value", - vec![ - (span.shrink_to_lo(), "Box::new(".to_string()), - (span.shrink_to_hi(), ")".to_string()), - ], - Applicability::MaybeIncorrect, - ); - } - } + } + + let body = self.tcx.hir().body(self.tcx.hir().body_owned_by(obligation.cause.body_id)); + + let mut visitor = ReturnsVisitor::default(); + visitor.visit_body(&body); + + let mut sugg = + vec![(span.shrink_to_lo(), "Box<".to_string()), (span.shrink_to_hi(), ">".to_string())]; + sugg.extend(visitor.returns.into_iter().flat_map(|expr| { + let span = expr.span.find_ancestor_in_same_ctxt(obligation.cause.span).unwrap_or(expr.span); + if !span.can_be_used_for_suggestions() { + vec![] + } else if let hir::ExprKind::Call(path, ..) = expr.kind + && let hir::ExprKind::Path(hir::QPath::TypeRelative(ty, method)) = path.kind + && method.ident.name == sym::new + && let hir::TyKind::Path(hir::QPath::Resolved(.., box_path)) = ty.kind + && box_path.res.opt_def_id().is_some_and(|def_id| Some(def_id) == self.tcx.lang_items().owned_box()) + { + // Don't box `Box::new` + vec![] } else { - // This is currently not possible to trigger because E0038 takes precedence, but - // leave it in for completeness in case anything changes in an earlier stage. - err.note(&format!( - "if trait `{}` were object-safe, you could return a trait object", - trait_obj, - )); + vec![ + (span.shrink_to_lo(), "Box::new(".to_string()), + (span.shrink_to_hi(), ")".to_string()), + ] } - err.note(trait_obj_msg); - err.note(&format!( - "if all the returned values were of the same type you could use `impl {}` as the \ - return type", - trait_obj, - )); - err.note(impl_trait_msg); - err.note("you can create a new `enum` with a variant for each returned type"); - } + })); + + err.multipart_suggestion( + "box the return type, and wrap all of the returned values in `Box::new`", + sugg, + Applicability::MaybeIncorrect, + ); + true } @@ -2014,7 +1883,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { } else { err.span_label( expr.span, - &format!("this returned value is of type `{}`", ty), + format!("this returned value is of type `{}`", ty), ); } } @@ -2164,7 +2033,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { ) { if let Some(assoc_item) = self.tcx.opt_associated_item(item_def_id) { if let ty::AssocKind::Const | ty::AssocKind::Type = assoc_item.kind { - err.note(&format!( + err.note(format!( "{}s cannot be accessed directly on a `trait`, they can only be \ accessed through a specific `impl`", self.tcx.def_kind_descr(assoc_item.kind.as_def_kind(), item_def_id) @@ -2428,10 +2297,9 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { && generator_did.is_local() // Try to avoid cycles. && !generator_within_in_progress_typeck + && let Some(generator_info) = self.tcx.mir_generator_witnesses(generator_did) { - let generator_info = &self.tcx.mir_generator_witnesses(generator_did); debug!(?generator_info); - 'find_source: for (variant, source_info) in generator_info.variant_fields.iter().zip(&generator_info.variant_source_info) { @@ -2594,7 +2462,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { } err.span_note( span, - &format!( + format!( "{} {} as this value is used across {}", future_or_generator, trait_explanation, an_await_or_yield ), @@ -2615,7 +2483,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { ); err.span_note( span, - &format!( + format!( "future {not_trait} as it awaits another future which {not_trait}", not_trait = trait_explanation ), @@ -2717,7 +2585,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { let mut span = MultiSpan::from_span(upvar_span); span.push_span_label(upvar_span, span_label); - err.span_note(span, &span_note); + err.span_note(span, span_note); } } @@ -2725,6 +2593,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { // bound that introduced the obligation (e.g. `T: Send`). debug!(?next_code); self.note_obligation_cause_code( + obligation.cause.body_id, err, obligation.predicate, obligation.param_env, @@ -2736,6 +2605,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { fn note_obligation_cause_code<T>( &self, + body_id: LocalDefId, err: &mut Diagnostic, predicate: T, param_env: ty::ParamEnv<'tcx>, @@ -2773,7 +2643,8 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { | ObligationCauseCode::LetElse | ObligationCauseCode::BinOp { .. } | ObligationCauseCode::AscribeUserTypeProvePredicate(..) - | ObligationCauseCode::RustCall => {} + | ObligationCauseCode::RustCall + | ObligationCauseCode::DropImpl => {} ObligationCauseCode::SliceOrArrayElem => { err.note("slice and array elements must have `Sized` type"); } @@ -2781,15 +2652,15 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { err.note("only the last element of a tuple may have a dynamically sized type"); } ObligationCauseCode::ProjectionWf(data) => { - err.note(&format!("required so that the projection `{data}` is well-formed")); + err.note(format!("required so that the projection `{data}` is well-formed")); } ObligationCauseCode::ReferenceOutlivesReferent(ref_ty) => { - err.note(&format!( + err.note(format!( "required so that reference `{ref_ty}` does not outlive its referent" )); } ObligationCauseCode::ObjectTypeBound(object_ty, region) => { - err.note(&format!( + err.note(format!( "required so that the lifetime bound of `{}` for `{}` is satisfied", region, object_ty, )); @@ -2825,35 +2696,32 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { if span.is_visible(sm) { let msg = format!("required by this bound in `{short_item_name}`"); multispan.push_span_label(span, msg); - err.span_note(multispan, &descr); + err.span_note(multispan, descr); } else { - err.span_note(tcx.def_span(item_def_id), &descr); + err.span_note(tcx.def_span(item_def_id), descr); } } - ObligationCauseCode::ObjectCastObligation(concrete_ty, object_ty) => { - let (concrete_ty, concrete_file) = - self.tcx.short_ty_string(self.resolve_vars_if_possible(concrete_ty)); - let (object_ty, object_file) = - self.tcx.short_ty_string(self.resolve_vars_if_possible(object_ty)); - err.note(&with_forced_trimmed_paths!(format!( - "required for the cast from `{concrete_ty}` to the object type `{object_ty}`", + ObligationCauseCode::Coercion { source, target } => { + let (source, source_file) = + self.tcx.short_ty_string(self.resolve_vars_if_possible(source)); + let (target, target_file) = + self.tcx.short_ty_string(self.resolve_vars_if_possible(target)); + err.note(with_forced_trimmed_paths!(format!( + "required for the cast from `{source}` to `{target}`", ))); - if let Some(file) = concrete_file { - err.note(&format!( - "the full name for the casted type has been written to '{}'", + if let Some(file) = source_file { + err.note(format!( + "the full name for the source type has been written to '{}'", file.display(), )); } - if let Some(file) = object_file { - err.note(&format!( - "the full name for the object type has been written to '{}'", + if let Some(file) = target_file { + err.note(format!( + "the full name for the target type has been written to '{}'", file.display(), )); } } - ObligationCauseCode::Coercion { source: _, target } => { - err.note(&format!("required by cast to type `{}`", self.ty_to_string(target))); - } ObligationCauseCode::RepeatElementCopy { is_const_fn } => { err.note( "the `Copy` trait is required because this value will be copied for each element of the array", @@ -3055,8 +2923,8 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { )); match ty.kind() { ty::Adt(def, _) => match self.tcx.opt_item_ident(def.did()) { - Some(ident) => err.span_note(ident.span, &msg), - None => err.note(&msg), + Some(ident) => err.span_note(ident.span, msg), + None => err.note(msg), }, ty::Alias(ty::Opaque, ty::AliasTy { def_id, .. }) => { // If the previous type is async fn, this is the future generated by the body of an async function. @@ -3068,7 +2936,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { "note_obligation_cause_code: check for async fn" ); if is_future - && obligated_types.last().map_or(false, |ty| match ty.kind() { + && obligated_types.last().is_some_and(|ty| match ty.kind() { ty::Generator(last_def_id, ..) => { tcx.generator_is_async(*last_def_id) } @@ -3077,7 +2945,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { { break 'print; } - err.span_note(self.tcx.def_span(def_id), &msg) + err.span_note(self.tcx.def_span(def_id), msg) } ty::GeneratorWitness(bound_tys) => { use std::fmt::Write; @@ -3113,7 +2981,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { let kind = tcx.generator_kind(def_id).unwrap().descr(); err.span_note( sp, - with_forced_trimmed_paths!(&format!( + with_forced_trimmed_paths!(format!( "required because it's used within this {kind}", )), ) @@ -3123,7 +2991,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { "required because it's used within this closure", ), ty::Str => err.note("`str` is considered to contain a `[u8]` slice for auto trait purposes"), - _ => err.note(&msg), + _ => err.note(msg), }; } } @@ -3135,6 +3003,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { // #74711: avoid a stack overflow ensure_sufficient_stack(|| { self.note_obligation_cause_code( + body_id, err, parent_predicate, param_env, @@ -3146,6 +3015,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { } else { ensure_sufficient_stack(|| { self.note_obligation_cause_code( + body_id, err, parent_predicate, param_env, @@ -3177,7 +3047,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { // FIXME: we should do something else so that it works even on crate foreign // auto traits. is_auto_trait = matches!(is_auto, hir::IsAuto::Yes); - err.span_note(ident.span, &msg); + err.span_note(ident.span, msg); } Some(Node::Item(hir::Item { kind: hir::ItemKind::Impl(hir::Impl { of_trait, self_ty, .. }), @@ -3206,15 +3076,15 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { "unsatisfied trait bound introduced here", ); } - err.span_note(spans, &msg); + err.span_note(spans, msg); } _ => { - err.note(&msg); + err.note(msg); } }; if let Some(file) = file { - err.note(&format!( + err.note(format!( "the full type name has been written to '{}'", file.display(), )); @@ -3254,19 +3124,19 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { parent_trait_pred = child_trait_pred; } if count > 0 { - err.note(&format!( + err.note(format!( "{} redundant requirement{} hidden", count, pluralize!(count) )); let (self_ty, file) = self.tcx.short_ty_string(parent_trait_pred.skip_binder().self_ty()); - err.note(&format!( + err.note(format!( "required for `{self_ty}` to implement `{}`", parent_trait_pred.print_modifiers_and_trait_path() )); if let Some(file) = file { - err.note(&format!( + err.note(format!( "the full type name has been written to '{}'", file.display(), )); @@ -3275,6 +3145,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { // #74711: avoid a stack overflow ensure_sufficient_stack(|| { self.note_obligation_cause_code( + body_id, err, parent_predicate, param_env, @@ -3290,6 +3161,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { // #74711: avoid a stack overflow ensure_sufficient_stack(|| { self.note_obligation_cause_code( + body_id, err, parent_predicate, param_env, @@ -3306,8 +3178,9 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { .. } => { self.note_function_argument_obligation( - arg_hir_id, + body_id, err, + arg_hir_id, parent_code, param_env, predicate, @@ -3315,6 +3188,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { ); ensure_sufficient_stack(|| { self.note_obligation_cause_code( + body_id, err, predicate, param_env, @@ -3347,7 +3221,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { { assoc_span.push_span_label(ident.span, "in this trait"); } - err.span_note(assoc_span, &msg); + err.span_note(assoc_span, msg); } ObligationCauseCode::TrivialBound => { err.help("see issue #48214"); @@ -3485,7 +3359,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { _ => None, }; let trait_pred = trait_pred.map_bound_ref(|tr| ty::TraitPredicate { - trait_ref: self.tcx.mk_trait_ref( + trait_ref: ty::TraitRef::new(self.tcx, trait_pred.def_id(), [field_ty].into_iter().chain(trait_substs), ), @@ -3503,7 +3377,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { if can_derive { err.span_suggestion_verbose( self.tcx.def_span(adt.did()).shrink_to_lo(), - &format!( + format!( "consider annotating `{}` with `#[derive({})]`", trait_pred.skip_binder().self_ty(), diagnostic_name, @@ -3536,8 +3410,9 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { } fn note_function_argument_obligation( &self, - arg_hir_id: HirId, + body_id: LocalDefId, err: &mut Diagnostic, + arg_hir_id: HirId, parent_code: &ObligationCauseCode<'tcx>, param_env: ty::ParamEnv<'tcx>, failed_pred: ty::Predicate<'tcx>, @@ -3570,7 +3445,6 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { // to an associated type (as seen from `trait_pred`) in the predicate. Like in // trait_pred `S: Sum<<Self as Iterator>::Item>` and predicate `i32: Sum<&()>` let mut type_diffs = vec![]; - if let ObligationCauseCode::ExprBindingObligation(def_id, _, _, idx) = parent_code.deref() && let Some(node_substs) = typeck_results.node_substs_opt(call_hir_id) && let where_clauses = self.tcx.predicates_of(def_id).instantiate(self.tcx, node_substs) @@ -3579,14 +3453,26 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { if let Some(where_pred) = where_pred.to_opt_poly_trait_pred() && let Some(failed_pred) = failed_pred.to_opt_poly_trait_pred() { - let mut c = CollectAllMismatches { - infcx: self.infcx, - param_env, - errors: vec![], + let where_pred = self.instantiate_binder_with_placeholders(where_pred); + let failed_pred = self.instantiate_binder_with_fresh_vars( + expr.span, + LateBoundRegionConversionTime::FnCall, + failed_pred + ); + + let zipped = + iter::zip(where_pred.trait_ref.substs, failed_pred.trait_ref.substs); + for (expected, actual) in zipped { + self.probe(|_| { + match self + .at(&ObligationCause::misc(expr.span, body_id), param_env) + .eq(DefineOpaqueTypes::No, expected, actual) + { + Ok(_) => (), // We ignore nested obligations here for now. + Err(err) => type_diffs.push(err), + } + }) }; - if let Ok(_) = c.relate(where_pred, failed_pred) { - type_diffs = c.errors; - } } else if let Some(where_pred) = where_pred.to_opt_poly_projection_pred() && let Some(failed_pred) = failed_pred.to_opt_poly_projection_pred() && let Some(found) = failed_pred.skip_binder().term.ty() @@ -3848,7 +3734,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { fn maybe_suggest_convert_to_slice( &self, err: &mut Diagnostic, - trait_ref: ty::Binder<'tcx, ty::TraitRef<'tcx>>, + trait_ref: ty::PolyTraitRef<'tcx>, candidate_impls: &[ImplCandidate<'tcx>], span: Span, ) { @@ -3890,7 +3776,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { .map(|trait_ref| trait_ref.trait_ref.self_ty()) .find(|t| is_slice(*t)) { - let msg = &format!("convert the array to a `{}` slice instead", slice_ty); + let msg = format!("convert the array to a `{}` slice instead", slice_ty); if let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(span) { let mut suggestions = vec![]; @@ -4103,37 +3989,6 @@ impl NextTypeParamName for &[hir::GenericParam<'_>] { } } -fn suggest_trait_object_return_type_alternatives( - err: &mut Diagnostic, - ret_ty: Span, - trait_obj: &str, - is_object_safe: bool, -) { - err.span_suggestion( - ret_ty, - &format!( - "use `impl {}` as the return type if all return paths have the same type but you \ - want to expose only the trait in the signature", - trait_obj, - ), - format!("impl {}", trait_obj), - Applicability::MaybeIncorrect, - ); - if is_object_safe { - err.multipart_suggestion( - &format!( - "use a boxed trait object if all return paths implement trait `{}`", - trait_obj, - ), - vec![ - (ret_ty.shrink_to_lo(), "Box<".to_string()), - (ret_ty.shrink_to_hi(), ">".to_string()), - ], - Applicability::MaybeIncorrect, - ); - } -} - /// Collect the spans that we see the generic param `param_did` struct ReplaceImplTraitVisitor<'a> { ty_spans: &'a mut Vec<Span>, diff --git a/compiler/rustc_trait_selection/src/traits/fulfill.rs b/compiler/rustc_trait_selection/src/traits/fulfill.rs index 26cadab3e..2f85c32b5 100644 --- a/compiler/rustc_trait_selection/src/traits/fulfill.rs +++ b/compiler/rustc_trait_selection/src/traits/fulfill.rs @@ -540,8 +540,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { use ty::ConstKind::Unevaluated; match (c1.kind(), c2.kind()) { (Unevaluated(a), Unevaluated(b)) - if a.def.did == b.def.did - && tcx.def_kind(a.def.did) == DefKind::AssocConst => + if a.def == b.def && tcx.def_kind(a.def) == DefKind::AssocConst => { if let Ok(new_obligations) = infcx .at(&obligation.cause, obligation.param_env) @@ -616,7 +615,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { (Err(ErrorHandled::Reported(reported)), _) | (_, Err(ErrorHandled::Reported(reported))) => ProcessResult::Error( CodeSelectionError(SelectionError::NotConstEvaluatable( - NotConstEvaluatable::Error(reported), + NotConstEvaluatable::Error(reported.into()), )), ), (Err(ErrorHandled::TooGeneric), _) | (_, Err(ErrorHandled::TooGeneric)) => { diff --git a/compiler/rustc_trait_selection/src/traits/misc.rs b/compiler/rustc_trait_selection/src/traits/misc.rs index af567c074..2210ef975 100644 --- a/compiler/rustc_trait_selection/src/traits/misc.rs +++ b/compiler/rustc_trait_selection/src/traits/misc.rs @@ -2,23 +2,29 @@ use crate::traits::{self, ObligationCause, ObligationCtxt}; +use hir::LangItem; use rustc_data_structures::fx::FxIndexSet; use rustc_hir as hir; use rustc_infer::infer::canonical::Canonical; use rustc_infer::infer::{RegionResolutionError, TyCtxtInferExt}; use rustc_infer::traits::query::NoSolution; use rustc_infer::{infer::outlives::env::OutlivesEnvironment, traits::FulfillmentError}; -use rustc_middle::ty::{self, ParamEnv, Ty, TyCtxt, TypeVisitableExt}; +use rustc_middle::ty::{self, AdtDef, GenericArg, List, ParamEnv, Ty, TyCtxt, TypeVisitableExt}; use rustc_span::DUMMY_SP; use super::outlives_bounds::InferCtxtExt; pub enum CopyImplementationError<'tcx> { - InfrigingFields(Vec<(&'tcx ty::FieldDef, Ty<'tcx>, InfringingFieldsReason<'tcx>)>), + InfringingFields(Vec<(&'tcx ty::FieldDef, Ty<'tcx>, InfringingFieldsReason<'tcx>)>), NotAnAdt, HasDestructor, } +pub enum ConstParamTyImplementationError<'tcx> { + InfrigingFields(Vec<(&'tcx ty::FieldDef, Ty<'tcx>, InfringingFieldsReason<'tcx>)>), + NotAnAdtOrBuiltinAllowed, +} + pub enum InfringingFieldsReason<'tcx> { Fulfill(Vec<FulfillmentError<'tcx>>), Regions(Vec<RegionResolutionError<'tcx>>), @@ -27,7 +33,10 @@ pub enum InfringingFieldsReason<'tcx> { /// Checks that the fields of the type (an ADT) all implement copy. /// /// If fields don't implement copy, return an error containing a list of -/// those violating fields. If it's not an ADT, returns `Err(NotAnAdt)`. +/// those violating fields. +/// +/// If it's not an ADT, int ty, `bool`, float ty, `char`, raw pointer, `!`, +/// a reference or an array returns `Err(NotAnAdt)`. pub fn type_allowed_to_implement_copy<'tcx>( tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>, @@ -47,12 +56,82 @@ pub fn type_allowed_to_implement_copy<'tcx>( | ty::Ref(_, _, hir::Mutability::Not) | ty::Array(..) => return Ok(()), - ty::Adt(adt, substs) => (adt, substs), + &ty::Adt(adt, substs) => (adt, substs), _ => return Err(CopyImplementationError::NotAnAdt), }; - let copy_def_id = tcx.require_lang_item(hir::LangItem::Copy, Some(parent_cause.span)); + all_fields_implement_trait( + tcx, + param_env, + self_type, + adt, + substs, + parent_cause, + hir::LangItem::Copy, + ) + .map_err(CopyImplementationError::InfringingFields)?; + + if adt.has_dtor(tcx) { + return Err(CopyImplementationError::HasDestructor); + } + + Ok(()) +} + +/// Checks that the fields of the type (an ADT) all implement `ConstParamTy`. +/// +/// If fields don't implement `ConstParamTy`, return an error containing a list of +/// those violating fields. +/// +/// If it's not an ADT, int ty, `bool` or `char`, returns `Err(NotAnAdtOrBuiltinAllowed)`. +pub fn type_allowed_to_implement_const_param_ty<'tcx>( + tcx: TyCtxt<'tcx>, + param_env: ty::ParamEnv<'tcx>, + self_type: Ty<'tcx>, + parent_cause: ObligationCause<'tcx>, +) -> Result<(), ConstParamTyImplementationError<'tcx>> { + let (adt, substs) = match self_type.kind() { + // `core` provides these impls. + ty::Uint(_) + | ty::Int(_) + | ty::Bool + | ty::Char + | ty::Str + | ty::Array(..) + | ty::Slice(_) + | ty::Ref(.., hir::Mutability::Not) => return Ok(()), + + &ty::Adt(adt, substs) => (adt, substs), + + _ => return Err(ConstParamTyImplementationError::NotAnAdtOrBuiltinAllowed), + }; + + all_fields_implement_trait( + tcx, + param_env, + self_type, + adt, + substs, + parent_cause, + hir::LangItem::ConstParamTy, + ) + .map_err(ConstParamTyImplementationError::InfrigingFields)?; + + Ok(()) +} + +/// Check that all fields of a given `adt` implement `lang_item` trait. +pub fn all_fields_implement_trait<'tcx>( + tcx: TyCtxt<'tcx>, + param_env: ty::ParamEnv<'tcx>, + self_type: Ty<'tcx>, + adt: AdtDef<'tcx>, + substs: &'tcx List<GenericArg<'tcx>>, + parent_cause: ObligationCause<'tcx>, + lang_item: LangItem, +) -> Result<(), Vec<(&'tcx ty::FieldDef, Ty<'tcx>, InfringingFieldsReason<'tcx>)>> { + let trait_def_id = tcx.require_lang_item(lang_item, Some(parent_cause.span)); let mut infringing = Vec::new(); for variant in adt.variants() { @@ -93,7 +172,7 @@ pub fn type_allowed_to_implement_copy<'tcx>( // between expected and found const-generic types. Don't report an // additional copy error here, since it's not typically useful. if !normalization_errors.is_empty() || ty.references_error() { - tcx.sess.delay_span_bug(field_span, format!("couldn't normalize struct field `{unnormalized_ty}` when checking Copy implementation")); + tcx.sess.delay_span_bug(field_span, format!("couldn't normalize struct field `{unnormalized_ty}` when checking {tr} implementation", tr = tcx.def_path_str(trait_def_id))); continue; } @@ -101,7 +180,7 @@ pub fn type_allowed_to_implement_copy<'tcx>( ObligationCause::dummy_with_span(field_ty_span), param_env, ty, - copy_def_id, + trait_def_id, ); let errors = ocx.select_all_or_error(); if !errors.is_empty() { @@ -124,15 +203,7 @@ pub fn type_allowed_to_implement_copy<'tcx>( } } - if !infringing.is_empty() { - return Err(CopyImplementationError::InfrigingFields(infringing)); - } - - if adt.has_dtor(tcx) { - return Err(CopyImplementationError::HasDestructor); - } - - Ok(()) + if infringing.is_empty() { Ok(()) } else { Err(infringing) } } pub fn check_tys_might_be_eq<'tcx>( diff --git a/compiler/rustc_trait_selection/src/traits/mod.rs b/compiler/rustc_trait_selection/src/traits/mod.rs index 8a203dec8..f265230ff 100644 --- a/compiler/rustc_trait_selection/src/traits/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/mod.rs @@ -17,6 +17,7 @@ pub mod query; mod select; mod specialize; mod structural_match; +mod structural_normalize; mod util; mod vtable; pub mod wf; @@ -26,6 +27,7 @@ use crate::infer::{InferCtxt, TyCtxtInferExt}; use crate::traits::error_reporting::TypeErrCtxtExt as _; use crate::traits::query::evaluate_obligation::InferCtxtExt as _; use rustc_errors::ErrorGuaranteed; +use rustc_middle::query::Providers; use rustc_middle::ty::fold::TypeFoldable; use rustc_middle::ty::visit::{TypeVisitable, TypeVisitableExt}; use rustc_middle::ty::{self, ToPredicate, Ty, TyCtxt, TypeSuperVisitable}; @@ -49,20 +51,24 @@ pub use self::object_safety::astconv_object_safety_violations; pub use self::object_safety::is_vtable_safe_method; pub use self::object_safety::MethodViolationCode; pub use self::object_safety::ObjectSafetyViolation; -pub use self::project::{normalize_projection_type, NormalizeExt}; +pub use self::project::NormalizeExt; +pub use self::project::{normalize_inherent_projection, normalize_projection_type}; pub use self::select::{EvaluationCache, SelectionCache, SelectionContext}; pub use self::select::{EvaluationResult, IntercrateAmbiguityCause, OverflowError}; pub use self::specialize::specialization_graph::FutureCompatOverlapError; pub use self::specialize::specialization_graph::FutureCompatOverlapErrorKind; -pub use self::specialize::{specialization_graph, translate_substs, OverlapError}; +pub use self::specialize::{ + specialization_graph, translate_substs, translate_substs_with_cause, OverlapError, +}; pub use self::structural_match::{ search_for_adt_const_param_violation, search_for_structural_match_violation, }; +pub use self::structural_normalize::StructurallyNormalizeExt; pub use self::util::elaborate; pub use self::util::{expand_trait_aliases, TraitAliasExpander}; pub use self::util::{get_vtable_index_of_object_method, impl_item_is_final, upcast_choices}; pub use self::util::{ - supertrait_def_ids, supertraits, transitive_bounds, transitive_bounds_that_define_assoc_type, + supertrait_def_ids, supertraits, transitive_bounds, transitive_bounds_that_define_assoc_item, SupertraitDefIds, }; @@ -127,7 +133,7 @@ pub fn type_known_to_meet_bound_modulo_regions<'tcx>( ty: Ty<'tcx>, def_id: DefId, ) -> bool { - let trait_ref = ty::Binder::dummy(infcx.tcx.mk_trait_ref(def_id, [ty])); + let trait_ref = ty::TraitRef::new(infcx.tcx, def_id, [ty]); pred_known_to_hold_modulo_regions(infcx, param_env, trait_ref.without_const()) } @@ -139,35 +145,36 @@ pub fn type_known_to_meet_bound_modulo_regions<'tcx>( fn pred_known_to_hold_modulo_regions<'tcx>( infcx: &InferCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>, - pred: impl ToPredicate<'tcx> + TypeVisitable<TyCtxt<'tcx>>, + pred: impl ToPredicate<'tcx>, ) -> bool { - let has_non_region_infer = pred.has_non_region_infer(); let obligation = Obligation::new(infcx.tcx, ObligationCause::dummy(), param_env, pred); let result = infcx.evaluate_obligation_no_overflow(&obligation); debug!(?result); - if result.must_apply_modulo_regions() && !has_non_region_infer { + if result.must_apply_modulo_regions() { true } else if result.may_apply() { - // Because of inference "guessing", selection can sometimes claim - // to succeed while the success requires a guess. To ensure - // this function's result remains infallible, we must confirm - // that guess. While imperfect, I believe this is sound. - - // The handling of regions in this area of the code is terrible, - // see issue #29149. We should be able to improve on this with - // NLL. - let ocx = ObligationCtxt::new(infcx); - ocx.register_obligation(obligation); - let errors = ocx.select_all_or_error(); - match errors.as_slice() { - [] => true, - errors => { - debug!(?errors); - false + // Sometimes obligations are ambiguous because the recursive evaluator + // is not smart enough, so we fall back to fulfillment when we're not certain + // that an obligation holds or not. Even still, we must make sure that + // the we do no inference in the process of checking this obligation. + let goal = infcx.resolve_vars_if_possible((obligation.predicate, obligation.param_env)); + infcx.probe(|_| { + let ocx = ObligationCtxt::new_in_snapshot(infcx); + ocx.register_obligation(obligation); + + let errors = ocx.select_all_or_error(); + match errors.as_slice() { + // Only known to hold if we did no inference. + [] => infcx.shallow_resolve(goal) == goal, + + errors => { + debug!(?errors); + false + } } - } + }) } else { false } @@ -203,7 +210,7 @@ fn do_normalize_predicates<'tcx>( } }; - debug!("do_normalize_predictes: normalized predicates = {:?}", predicates); + debug!("do_normalize_predicates: normalized predicates = {:?}", predicates); // We can use the `elaborated_env` here; the region code only // cares about declarations like `'a: 'b`. @@ -414,7 +421,7 @@ fn subst_and_check_impossible_predicates<'tcx>( predicates.push(ty::Binder::dummy(trait_ref).to_predicate(tcx)); } - predicates.retain(|predicate| !predicate.needs_subst()); + predicates.retain(|predicate| !predicate.has_param()); let result = impossible_predicates(tcx, predicates); debug!("subst_and_check_impossible_predicates(key={:?}) = {:?}", key, result); @@ -450,7 +457,7 @@ fn is_impossible_method(tcx: TyCtxt<'_>, (impl_def_id, trait_item_def_id): (DefI { return ControlFlow::Break(()); } - r.super_visit_with(self) + ControlFlow::Continue(()) } fn visit_const(&mut self, ct: ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> { if let ty::ConstKind::Param(param) = ct.kind() @@ -495,10 +502,10 @@ fn is_impossible_method(tcx: TyCtxt<'_>, (impl_def_id, trait_item_def_id): (DefI false } -pub fn provide(providers: &mut ty::query::Providers) { +pub fn provide(providers: &mut Providers) { object_safety::provide(providers); vtable::provide(providers); - *providers = ty::query::Providers { + *providers = Providers { specialization_graph_of: specialize::specialization_graph_provider, specializes: specialize::specializes, subst_and_check_impossible_predicates, diff --git a/compiler/rustc_trait_selection/src/traits/object_safety.rs b/compiler/rustc_trait_selection/src/traits/object_safety.rs index b8ad1925e..c81bf6ebc 100644 --- a/compiler/rustc_trait_selection/src/traits/object_safety.rs +++ b/compiler/rustc_trait_selection/src/traits/object_safety.rs @@ -16,6 +16,7 @@ use crate::traits::{self, Obligation, ObligationCause}; use rustc_errors::{DelayDm, FatalError, MultiSpan}; use rustc_hir as hir; use rustc_hir::def_id::DefId; +use rustc_middle::query::Providers; use rustc_middle::ty::subst::{GenericArg, InternalSubsts}; use rustc_middle::ty::{ self, EarlyBinder, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitor, @@ -279,7 +280,7 @@ fn predicates_reference_self( trait_def_id: DefId, supertraits_only: bool, ) -> SmallVec<[Span; 1]> { - let trait_ref = ty::TraitRef::identity(tcx, trait_def_id); + let trait_ref = ty::Binder::dummy(ty::TraitRef::identity(tcx, trait_def_id)); let predicates = if supertraits_only { tcx.super_predicates_of(trait_def_id) } else { @@ -297,8 +298,8 @@ fn bounds_reference_self(tcx: TyCtxt<'_>, trait_def_id: DefId) -> SmallVec<[Span tcx.associated_items(trait_def_id) .in_definition_order() .filter(|item| item.kind == ty::AssocKind::Type) - .flat_map(|item| tcx.explicit_item_bounds(item.def_id)) - .filter_map(|pred_span| predicate_references_self(tcx, *pred_span)) + .flat_map(|item| tcx.explicit_item_bounds(item.def_id).subst_identity_iter_copied()) + .filter_map(|pred_span| predicate_references_self(tcx, pred_span)) .collect() } @@ -525,7 +526,7 @@ fn virtual_call_violation_for_method<'tcx>( // #78372 tcx.sess.delay_span_bug( tcx.def_span(method.def_id), - &format!("error: {}\n while computing layout for type {:?}", err, ty), + format!("error: {}\n while computing layout for type {:?}", err, ty), ); None } @@ -541,7 +542,7 @@ fn virtual_call_violation_for_method<'tcx>( abi => { tcx.sess.delay_span_bug( tcx.def_span(method.def_id), - &format!( + format!( "receiver when `Self = ()` should have a Scalar ABI; found {:?}", abi ), @@ -560,7 +561,7 @@ fn virtual_call_violation_for_method<'tcx>( abi => { tcx.sess.delay_span_bug( tcx.def_span(method.def_id), - &format!( + format!( "receiver when `Self = {}` should have a ScalarPair ABI; found {:?}", trait_object_ty, abi ), @@ -661,9 +662,9 @@ fn object_ty_for_trait<'tcx>( let trait_ref = ty::TraitRef::identity(tcx, trait_def_id); debug!(?trait_ref); - let trait_predicate = trait_ref.map_bound(|trait_ref| { - ty::ExistentialPredicate::Trait(ty::ExistentialTraitRef::erase_self_ty(tcx, trait_ref)) - }); + let trait_predicate = ty::Binder::dummy(ty::ExistentialPredicate::Trait( + ty::ExistentialTraitRef::erase_self_ty(tcx, trait_ref), + )); debug!(?trait_predicate); let pred: ty::Predicate<'tcx> = trait_ref.to_predicate(tcx); @@ -769,11 +770,10 @@ fn receiver_is_dispatchable<'tcx>( let param_env = tcx.param_env(method.def_id); // Self: Unsize<U> - let unsize_predicate = ty::Binder::dummy( - tcx.mk_trait_ref(unsize_did, [tcx.types.self_param, unsized_self_ty]), - ) - .without_const() - .to_predicate(tcx); + let unsize_predicate = + ty::TraitRef::new(tcx, unsize_did, [tcx.types.self_param, unsized_self_ty]) + .without_const() + .to_predicate(tcx); // U: Trait<Arg1, ..., ArgN> let trait_predicate = { @@ -782,7 +782,7 @@ fn receiver_is_dispatchable<'tcx>( if param.index == 0 { unsized_self_ty.into() } else { tcx.mk_param_from_def(param) } }); - ty::Binder::dummy(tcx.mk_trait_ref(trait_def_id, substs)).to_predicate(tcx) + ty::TraitRef::new(tcx, trait_def_id, substs).to_predicate(tcx) }; let caller_bounds = @@ -797,9 +797,8 @@ fn receiver_is_dispatchable<'tcx>( // Receiver: DispatchFromDyn<Receiver[Self => U]> let obligation = { - let predicate = ty::Binder::dummy( - tcx.mk_trait_ref(dispatch_from_dyn_did, [receiver_ty, unsized_receiver_ty]), - ); + let predicate = + ty::TraitRef::new(tcx, dispatch_from_dyn_did, [receiver_ty, unsized_receiver_ty]); Obligation::new(tcx, ObligationCause::dummy(), param_env, predicate) }; @@ -882,7 +881,8 @@ fn contains_illegal_self_type_reference<'tcx, T: TypeVisitable<TyCtxt<'tcx>>>( // Compute supertraits of current trait lazily. if self.supertraits.is_none() { - let trait_ref = ty::TraitRef::identity(self.tcx, self.trait_def_id); + let trait_ref = + ty::Binder::dummy(ty::TraitRef::identity(self.tcx, self.trait_def_id)); self.supertraits = Some( traits::supertraits(self.tcx, trait_ref).map(|t| t.def_id()).collect(), ); @@ -948,7 +948,6 @@ pub fn contains_illegal_impl_trait_in_trait<'tcx>( }) } -pub fn provide(providers: &mut ty::query::Providers) { - *providers = - ty::query::Providers { object_safety_violations, check_is_object_safe, ..*providers }; +pub fn provide(providers: &mut Providers) { + *providers = Providers { object_safety_violations, check_is_object_safe, ..*providers }; } diff --git a/compiler/rustc_trait_selection/src/traits/outlives_bounds.rs b/compiler/rustc_trait_selection/src/traits/outlives_bounds.rs index cff3d277a..f8d056e32 100644 --- a/compiler/rustc_trait_selection/src/traits/outlives_bounds.rs +++ b/compiler/rustc_trait_selection/src/traits/outlives_bounds.rs @@ -1,9 +1,9 @@ use crate::infer::InferCtxt; -use crate::traits::query::type_op::{self, TypeOp, TypeOpOutput}; -use crate::traits::query::NoSolution; use crate::traits::{ObligationCause, ObligationCtxt}; use rustc_data_structures::fx::FxIndexSet; use rustc_infer::infer::resolve::OpportunisticRegionResolver; +use rustc_infer::infer::InferOk; +use rustc_middle::infer::canonical::{OriginalQueryValues, QueryRegionConstraints}; use rustc_middle::ty::{self, ParamEnv, Ty, TypeFolder, TypeVisitableExt}; use rustc_span::def_id::LocalDefId; @@ -55,26 +55,42 @@ impl<'a, 'tcx: 'a> InferCtxtExt<'a, 'tcx> for InferCtxt<'tcx> { ) -> Vec<OutlivesBound<'tcx>> { let ty = self.resolve_vars_if_possible(ty); let ty = OpportunisticRegionResolver::new(self).fold_ty(ty); - assert!(!ty.needs_infer()); - let span = self.tcx.def_span(body_id); - let result = param_env - .and(type_op::implied_outlives_bounds::ImpliedOutlivesBounds { ty }) - .fully_perform(self); - let result = match result { - Ok(r) => r, - Err(NoSolution) => { - self.tcx.sess.delay_span_bug( - span, - "implied_outlives_bounds failed to solve all obligations", - ); - return vec![]; - } + // We do not expect existential variables in implied bounds. + // We may however encounter unconstrained lifetime variables in invalid + // code. See #110161 for context. + assert!(!ty.has_non_region_infer()); + if ty.has_infer() { + self.tcx.sess.delay_span_bug( + self.tcx.def_span(body_id), + "skipped implied_outlives_bounds due to unconstrained lifetimes", + ); + return vec![]; + } + + let mut canonical_var_values = OriginalQueryValues::default(); + let canonical_ty = + self.canonicalize_query_keep_static(param_env.and(ty), &mut canonical_var_values); + let Ok(canonical_result) = self.tcx.implied_outlives_bounds(canonical_ty) else { + return vec![]; + }; + + let mut constraints = QueryRegionConstraints::default(); + let Ok(InferOk { value, obligations }) = self + .instantiate_nll_query_response_and_region_obligations( + &ObligationCause::dummy(), + param_env, + &canonical_var_values, + canonical_result, + &mut constraints, + ) else { + return vec![]; }; + assert_eq!(&obligations, &[]); - let TypeOpOutput { output, constraints, .. } = result; + if !constraints.is_empty() { + let span = self.tcx.def_span(body_id); - if let Some(constraints) = constraints { debug!(?constraints); if !constraints.member_constraints.is_empty() { span_bug!(span, "{:#?}", constraints.member_constraints); @@ -101,7 +117,7 @@ impl<'a, 'tcx: 'a> InferCtxtExt<'a, 'tcx> for InferCtxt<'tcx> { } }; - output + value } fn implied_bounds_tys( diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs index 826fc63ca..510698971 100644 --- a/compiler/rustc_trait_selection/src/traits/project.rs +++ b/compiler/rustc_trait_selection/src/traits/project.rs @@ -16,6 +16,7 @@ use super::{ }; use super::{Normalized, NormalizedTy, ProjectionCacheEntry, ProjectionCacheKey}; +use crate::errors::InherentProjectionNormalizationOverflow; use crate::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind}; use crate::infer::{InferCtxt, InferOk, LateBoundRegionConversionTime}; use crate::traits::error_reporting::TypeErrCtxtExt as _; @@ -370,10 +371,14 @@ pub(crate) fn needs_normalization<'tcx, T: TypeVisitable<TyCtxt<'tcx>>>( reveal: Reveal, ) -> bool { match reveal { - Reveal::UserFacing => value - .has_type_flags(ty::TypeFlags::HAS_TY_PROJECTION | ty::TypeFlags::HAS_CT_PROJECTION), + Reveal::UserFacing => value.has_type_flags( + ty::TypeFlags::HAS_TY_PROJECTION + | ty::TypeFlags::HAS_TY_INHERENT + | ty::TypeFlags::HAS_CT_PROJECTION, + ), Reveal::All => value.has_type_flags( ty::TypeFlags::HAS_TY_PROJECTION + | ty::TypeFlags::HAS_TY_INHERENT | ty::TypeFlags::HAS_TY_OPAQUE | ty::TypeFlags::HAS_CT_PROJECTION, ), @@ -616,6 +621,51 @@ impl<'a, 'b, 'tcx> TypeFolder<TyCtxt<'tcx>> for AssocTypeNormalizer<'a, 'b, 'tcx ); normalized_ty } + + ty::Inherent if !data.has_escaping_bound_vars() => { + // This branch is *mostly* just an optimization: when we don't + // have escaping bound vars, we don't need to replace them with + // placeholders (see branch below). *Also*, we know that we can + // register an obligation to *later* project, since we know + // there won't be bound vars there. + + let data = data.fold_with(self); + + // FIXME(inherent_associated_types): Do we need to honor `self.eager_inference_replacement` + // here like `ty::Projection`? + normalize_inherent_projection( + self.selcx, + self.param_env, + data, + self.cause.clone(), + self.depth, + &mut self.obligations, + ) + } + + ty::Inherent => { + let infcx = self.selcx.infcx; + let (data, mapped_regions, mapped_types, mapped_consts) = + BoundVarReplacer::replace_bound_vars(infcx, &mut self.universes, data); + let data = data.fold_with(self); + let ty = normalize_inherent_projection( + self.selcx, + self.param_env, + data, + self.cause.clone(), + self.depth, + &mut self.obligations, + ); + + PlaceholderReplacer::replace_placeholders( + infcx, + mapped_regions, + mapped_types, + mapped_consts, + &self.universes, + ty, + ) + } } } @@ -1204,6 +1254,115 @@ fn normalize_to_error<'a, 'tcx>( Normalized { value: new_value, obligations: vec![trait_obligation] } } +/// Confirm and normalize the given inherent projection. +#[instrument(level = "debug", skip(selcx, param_env, cause, obligations))] +pub fn normalize_inherent_projection<'a, 'b, 'tcx>( + selcx: &'a mut SelectionContext<'b, 'tcx>, + param_env: ty::ParamEnv<'tcx>, + alias_ty: ty::AliasTy<'tcx>, + cause: ObligationCause<'tcx>, + depth: usize, + obligations: &mut Vec<PredicateObligation<'tcx>>, +) -> Ty<'tcx> { + let tcx = selcx.tcx(); + + if !tcx.recursion_limit().value_within_limit(depth) { + // Halt compilation because it is important that overflows never be masked. + tcx.sess.emit_fatal(InherentProjectionNormalizationOverflow { + span: cause.span, + ty: alias_ty.to_string(), + }); + } + + let substs = compute_inherent_assoc_ty_substs( + selcx, + param_env, + alias_ty, + cause.clone(), + depth, + obligations, + ); + + // Register the obligations arising from the impl and from the associated type itself. + let predicates = tcx.predicates_of(alias_ty.def_id).instantiate(tcx, substs); + for (predicate, span) in predicates { + let predicate = normalize_with_depth_to( + selcx, + param_env, + cause.clone(), + depth + 1, + predicate, + obligations, + ); + + let nested_cause = ObligationCause::new( + cause.span, + cause.body_id, + // FIXME(inherent_associated_types): Since we can't pass along the self type to the + // cause code, inherent projections will be printed with identity substitutions in + // diagnostics which is not ideal. + // Consider creating separate cause codes for this specific situation. + if span.is_dummy() { + super::ItemObligation(alias_ty.def_id) + } else { + super::BindingObligation(alias_ty.def_id, span) + }, + ); + + obligations.push(Obligation::with_depth( + tcx, + nested_cause, + depth + 1, + param_env, + predicate, + )); + } + + let ty = tcx.type_of(alias_ty.def_id).subst(tcx, substs); + + let mut ty = selcx.infcx.resolve_vars_if_possible(ty); + if ty.has_projections() { + ty = normalize_with_depth_to(selcx, param_env, cause.clone(), depth + 1, ty, obligations); + } + + ty +} + +pub fn compute_inherent_assoc_ty_substs<'a, 'b, 'tcx>( + selcx: &'a mut SelectionContext<'b, 'tcx>, + param_env: ty::ParamEnv<'tcx>, + alias_ty: ty::AliasTy<'tcx>, + cause: ObligationCause<'tcx>, + depth: usize, + obligations: &mut Vec<PredicateObligation<'tcx>>, +) -> ty::SubstsRef<'tcx> { + let tcx = selcx.tcx(); + + let impl_def_id = tcx.parent(alias_ty.def_id); + let impl_substs = selcx.infcx.fresh_substs_for_item(cause.span, impl_def_id); + + let impl_ty = tcx.type_of(impl_def_id).subst(tcx, impl_substs); + let impl_ty = + normalize_with_depth_to(selcx, param_env, cause.clone(), depth + 1, impl_ty, obligations); + + // Infer the generic parameters of the impl by unifying the + // impl type with the self type of the projection. + let self_ty = alias_ty.self_ty(); + match selcx.infcx.at(&cause, param_env).eq(DefineOpaqueTypes::No, impl_ty, self_ty) { + Ok(mut ok) => obligations.append(&mut ok.obligations), + Err(_) => { + tcx.sess.delay_span_bug( + cause.span, + format!( + "{self_ty:?} was a subtype of {impl_ty:?} during selection but now it is not" + ), + ); + } + } + + alias_ty.rebase_substs_onto_impl(impl_substs, tcx) +} + enum Projected<'tcx> { Progress(Progress<'tcx>), NoProgress(ty::Term<'tcx>), @@ -1272,14 +1431,29 @@ fn project<'cx, 'tcx>( ProjectionCandidateSet::Single(candidate) => { Ok(Projected::Progress(confirm_candidate(selcx, obligation, candidate))) } - ProjectionCandidateSet::None => Ok(Projected::NoProgress( - // FIXME(associated_const_generics): this may need to change in the future? - // need to investigate whether or not this is fine. - selcx - .tcx() - .mk_projection(obligation.predicate.def_id, obligation.predicate.substs) - .into(), - )), + ProjectionCandidateSet::None => { + let tcx = selcx.tcx(); + let term = match tcx.def_kind(obligation.predicate.def_id) { + DefKind::AssocTy | DefKind::ImplTraitPlaceholder => tcx + .mk_projection(obligation.predicate.def_id, obligation.predicate.substs) + .into(), + DefKind::AssocConst => tcx + .mk_const( + ty::ConstKind::Unevaluated(ty::UnevaluatedConst::new( + obligation.predicate.def_id, + obligation.predicate.substs, + )), + tcx.type_of(obligation.predicate.def_id) + .subst(tcx, obligation.predicate.substs), + ) + .into(), + kind => { + bug!("unknown projection def-id: {}", kind.descr(obligation.predicate.def_id)) + } + }; + + Ok(Projected::NoProgress(term)) + } // Error occurred while trying to processing impls. ProjectionCandidateSet::Error(e) => Err(ProjectionError::TraitSelectionError(e)), // Inherent ambiguity that prevents us from even enumerating the @@ -1304,7 +1478,7 @@ fn assemble_candidate_for_impl_trait_in_trait<'cx, 'tcx>( let trait_substs = obligation.predicate.substs.truncate_to(tcx, tcx.generics_of(trait_def_id)); // FIXME(named-returns): Binders - let trait_predicate = ty::Binder::dummy(tcx.mk_trait_ref(trait_def_id, trait_substs)); + let trait_predicate = ty::TraitRef::new(tcx, trait_def_id, trait_substs); let _ = selcx.infcx.commit_if_ok(|_| { match selcx.select(&obligation.with(tcx, trait_predicate)) { @@ -1369,7 +1543,10 @@ fn assemble_candidates_from_trait_def<'cx, 'tcx>( // Check whether the self-type is itself a projection. // If so, extract what we know from the trait and try to come up with a good answer. let bounds = match *obligation.predicate.self_ty().kind() { - ty::Alias(_, ref data) => tcx.item_bounds(data.def_id).subst(tcx, data.substs), + // Excluding IATs here as they don't have meaningful item bounds. + ty::Alias(ty::Projection | ty::Opaque, ref data) => { + tcx.item_bounds(data.def_id).subst(tcx, data.substs) + } ty::Infer(ty::TyVar(_)) => { // If the self-type is an inference variable, then it MAY wind up // being a projected type, so induce an ambiguity. @@ -1667,10 +1844,8 @@ fn assemble_candidates_from_impls<'cx, 'tcx>( if selcx.infcx.predicate_must_hold_modulo_regions( &obligation.with( selcx.tcx(), - ty::Binder::dummy( - selcx.tcx().at(obligation.cause.span()).mk_trait_ref(LangItem::Sized, [self_ty]), - ) - .without_const(), + ty::TraitRef::from_lang_item(selcx.tcx(), LangItem::Sized, obligation.cause.span(),[self_ty]) + .without_const(), ), ) => { @@ -1734,7 +1909,7 @@ fn assemble_candidates_from_impls<'cx, 'tcx>( // These traits have no associated types. selcx.tcx().sess.delay_span_bug( obligation.cause.span, - &format!("Cannot project an associated type from `{:?}`", impl_source), + format!("Cannot project an associated type from `{:?}`", impl_source), ); return Err(()); } @@ -1933,8 +2108,11 @@ fn confirm_builtin_candidate<'cx, 'tcx>( ) }); if check_is_sized { - let sized_predicate = ty::Binder::dummy( - tcx.at(obligation.cause.span()).mk_trait_ref(LangItem::Sized, [self_ty]), + let sized_predicate = ty::TraitRef::from_lang_item( + tcx, + LangItem::Sized, + obligation.cause.span(), + [self_ty], ) .without_const(); obligations.push(obligation.with(tcx, sized_predicate)); @@ -2085,7 +2263,7 @@ fn confirm_param_env_candidate<'cx, 'tcx>( obligation, poly_cache_entry, e, ); debug!("confirm_param_env_candidate: {}", msg); - let err = infcx.tcx.ty_error_with_message(obligation.cause.span, &msg); + let err = infcx.tcx.ty_error_with_message(obligation.cause.span, msg); Progress { term: err.into(), obligations: vec![] } } } @@ -2131,9 +2309,8 @@ fn confirm_impl_candidate<'cx, 'tcx>( let ty = tcx.type_of(assoc_ty.item.def_id); let is_const = matches!(tcx.def_kind(assoc_ty.item.def_id), DefKind::AssocConst); let term: ty::EarlyBinder<ty::Term<'tcx>> = if is_const { - let identity_substs = - crate::traits::InternalSubsts::identity_for_item(tcx, assoc_ty.item.def_id); - let did = ty::WithOptConstParam::unknown(assoc_ty.item.def_id); + let did = assoc_ty.item.def_id; + let identity_substs = crate::traits::InternalSubsts::identity_for_item(tcx, did); let kind = ty::ConstKind::Unevaluated(ty::UnevaluatedConst::new(did, identity_substs)); ty.map_bound(|ty| tcx.mk_const(kind, ty).into()) } else { @@ -2277,11 +2454,10 @@ fn confirm_impl_trait_in_trait_candidate<'tcx>( obligation.param_env, cause.clone(), obligation.recursion_depth + 1, - tcx.bound_return_position_impl_trait_in_trait_tys(impl_fn_def_id) - .map_bound(|tys| { - tys.map_or_else(|guar| tcx.ty_error(guar), |tys| tys[&obligation.predicate.def_id]) - }) - .subst(tcx, impl_fn_substs), + tcx.collect_return_position_impl_trait_in_trait_tys(impl_fn_def_id).map_or_else( + |guar| tcx.ty_error(guar), + |tys| tys[&obligation.predicate.def_id].subst(tcx, impl_fn_substs), + ), &mut obligations, ); diff --git a/compiler/rustc_trait_selection/src/traits/query/dropck_outlives.rs b/compiler/rustc_trait_selection/src/traits/query/dropck_outlives.rs index 455b53bfb..4e4172e7f 100644 --- a/compiler/rustc_trait_selection/src/traits/query/dropck_outlives.rs +++ b/compiler/rustc_trait_selection/src/traits/query/dropck_outlives.rs @@ -1,6 +1,11 @@ -use rustc_middle::ty::{self, Ty, TyCtxt}; +use crate::traits::query::normalize::QueryNormalizeExt; +use crate::traits::query::NoSolution; +use crate::traits::{Normalized, ObligationCause, ObligationCtxt}; -pub use rustc_middle::traits::query::{DropckConstraint, DropckOutlivesResult}; +use rustc_data_structures::fx::FxHashSet; +use rustc_middle::traits::query::{DropckConstraint, DropckOutlivesResult}; +use rustc_middle::ty::{self, EarlyBinder, ParamEnvAnd, Ty, TyCtxt}; +use rustc_span::source_map::{Span, DUMMY_SP}; /// This returns true if the type `ty` is "trivial" for /// dropck-outlives -- that is, if it doesn't require any types to @@ -71,3 +76,263 @@ pub fn trivial_dropck_outlives<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> bool { | ty::Generator(..) => false, } } + +pub fn compute_dropck_outlives_inner<'tcx>( + ocx: &ObligationCtxt<'_, 'tcx>, + goal: ParamEnvAnd<'tcx, Ty<'tcx>>, +) -> Result<DropckOutlivesResult<'tcx>, NoSolution> { + let tcx = ocx.infcx.tcx; + let ParamEnvAnd { param_env, value: for_ty } = goal; + + let mut result = DropckOutlivesResult { kinds: vec![], overflows: vec![] }; + + // A stack of types left to process. Each round, we pop + // something from the stack and invoke + // `dtorck_constraint_for_ty_inner`. This may produce new types that + // have to be pushed on the stack. This continues until we have explored + // all the reachable types from the type `for_ty`. + // + // Example: Imagine that we have the following code: + // + // ```rust + // struct A { + // value: B, + // children: Vec<A>, + // } + // + // struct B { + // value: u32 + // } + // + // fn f() { + // let a: A = ...; + // .. + // } // here, `a` is dropped + // ``` + // + // at the point where `a` is dropped, we need to figure out + // which types inside of `a` contain region data that may be + // accessed by any destructors in `a`. We begin by pushing `A` + // onto the stack, as that is the type of `a`. We will then + // invoke `dtorck_constraint_for_ty_inner` which will expand `A` + // into the types of its fields `(B, Vec<A>)`. These will get + // pushed onto the stack. Eventually, expanding `Vec<A>` will + // lead to us trying to push `A` a second time -- to prevent + // infinite recursion, we notice that `A` was already pushed + // once and stop. + let mut ty_stack = vec![(for_ty, 0)]; + + // Set used to detect infinite recursion. + let mut ty_set = FxHashSet::default(); + + let cause = ObligationCause::dummy(); + let mut constraints = DropckConstraint::empty(); + while let Some((ty, depth)) = ty_stack.pop() { + debug!( + "{} kinds, {} overflows, {} ty_stack", + result.kinds.len(), + result.overflows.len(), + ty_stack.len() + ); + dtorck_constraint_for_ty_inner(tcx, DUMMY_SP, for_ty, depth, ty, &mut constraints)?; + + // "outlives" represent types/regions that may be touched + // by a destructor. + result.kinds.append(&mut constraints.outlives); + result.overflows.append(&mut constraints.overflows); + + // If we have even one overflow, we should stop trying to evaluate further -- + // chances are, the subsequent overflows for this evaluation won't provide useful + // information and will just decrease the speed at which we can emit these errors + // (since we'll be printing for just that much longer for the often enormous types + // that result here). + if !result.overflows.is_empty() { + break; + } + + // dtorck types are "types that will get dropped but which + // do not themselves define a destructor", more or less. We have + // to push them onto the stack to be expanded. + for ty in constraints.dtorck_types.drain(..) { + let Normalized { value: ty, obligations } = + ocx.infcx.at(&cause, param_env).query_normalize(ty)?; + ocx.register_obligations(obligations); + + debug!("dropck_outlives: ty from dtorck_types = {:?}", ty); + + match ty.kind() { + // All parameters live for the duration of the + // function. + ty::Param(..) => {} + + // A projection that we couldn't resolve - it + // might have a destructor. + ty::Alias(..) => { + result.kinds.push(ty.into()); + } + + _ => { + if ty_set.insert(ty) { + ty_stack.push((ty, depth + 1)); + } + } + } + } + } + + debug!("dropck_outlives: result = {:#?}", result); + Ok(result) +} + +/// Returns a set of constraints that needs to be satisfied in +/// order for `ty` to be valid for destruction. +pub fn dtorck_constraint_for_ty_inner<'tcx>( + tcx: TyCtxt<'tcx>, + span: Span, + for_ty: Ty<'tcx>, + depth: usize, + ty: Ty<'tcx>, + constraints: &mut DropckConstraint<'tcx>, +) -> Result<(), NoSolution> { + debug!("dtorck_constraint_for_ty_inner({:?}, {:?}, {:?}, {:?})", span, for_ty, depth, ty); + + if !tcx.recursion_limit().value_within_limit(depth) { + constraints.overflows.push(ty); + return Ok(()); + } + + if trivial_dropck_outlives(tcx, ty) { + return Ok(()); + } + + match ty.kind() { + ty::Bool + | ty::Char + | ty::Int(_) + | ty::Uint(_) + | ty::Float(_) + | ty::Str + | ty::Never + | ty::Foreign(..) + | ty::RawPtr(..) + | ty::Ref(..) + | ty::FnDef(..) + | ty::FnPtr(_) + | ty::GeneratorWitness(..) + | ty::GeneratorWitnessMIR(..) => { + // these types never have a destructor + } + + ty::Array(ety, _) | ty::Slice(ety) => { + // single-element containers, behave like their element + rustc_data_structures::stack::ensure_sufficient_stack(|| { + dtorck_constraint_for_ty_inner(tcx, span, for_ty, depth + 1, *ety, constraints) + })?; + } + + ty::Tuple(tys) => rustc_data_structures::stack::ensure_sufficient_stack(|| { + for ty in tys.iter() { + dtorck_constraint_for_ty_inner(tcx, span, for_ty, depth + 1, ty, constraints)?; + } + Ok::<_, NoSolution>(()) + })?, + + ty::Closure(_, substs) => { + if !substs.as_closure().is_valid() { + // By the time this code runs, all type variables ought to + // be fully resolved. + + tcx.sess.delay_span_bug( + span, + format!("upvar_tys for closure not found. Expected capture information for closure {ty}",), + ); + return Err(NoSolution); + } + + rustc_data_structures::stack::ensure_sufficient_stack(|| { + for ty in substs.as_closure().upvar_tys() { + dtorck_constraint_for_ty_inner(tcx, span, for_ty, depth + 1, ty, constraints)?; + } + Ok::<_, NoSolution>(()) + })? + } + + ty::Generator(_, substs, _movability) => { + // rust-lang/rust#49918: types can be constructed, stored + // in the interior, and sit idle when generator yields + // (and is subsequently dropped). + // + // It would be nice to descend into interior of a + // generator to determine what effects dropping it might + // have (by looking at any drop effects associated with + // its interior). + // + // However, the interior's representation uses things like + // GeneratorWitness that explicitly assume they are not + // traversed in such a manner. So instead, we will + // simplify things for now by treating all generators as + // if they were like trait objects, where its upvars must + // all be alive for the generator's (potential) + // destructor. + // + // In particular, skipping over `_interior` is safe + // because any side-effects from dropping `_interior` can + // only take place through references with lifetimes + // derived from lifetimes attached to the upvars and resume + // argument, and we *do* incorporate those here. + + if !substs.as_generator().is_valid() { + // By the time this code runs, all type variables ought to + // be fully resolved. + tcx.sess.delay_span_bug( + span, + format!("upvar_tys for generator not found. Expected capture information for generator {ty}",), + ); + return Err(NoSolution); + } + + constraints.outlives.extend( + substs + .as_generator() + .upvar_tys() + .map(|t| -> ty::subst::GenericArg<'tcx> { t.into() }), + ); + constraints.outlives.push(substs.as_generator().resume_ty().into()); + } + + ty::Adt(def, substs) => { + let DropckConstraint { dtorck_types, outlives, overflows } = + tcx.at(span).adt_dtorck_constraint(def.did())?; + // FIXME: we can try to recursively `dtorck_constraint_on_ty` + // there, but that needs some way to handle cycles. + constraints + .dtorck_types + .extend(dtorck_types.iter().map(|t| EarlyBinder(*t).subst(tcx, substs))); + constraints + .outlives + .extend(outlives.iter().map(|t| EarlyBinder(*t).subst(tcx, substs))); + constraints + .overflows + .extend(overflows.iter().map(|t| EarlyBinder(*t).subst(tcx, substs))); + } + + // Objects must be alive in order for their destructor + // to be called. + ty::Dynamic(..) => { + constraints.outlives.push(ty.into()); + } + + // Types that can't be resolved. Pass them forward. + ty::Alias(..) | ty::Param(..) => { + constraints.dtorck_types.push(ty); + } + + ty::Placeholder(..) | ty::Bound(..) | ty::Infer(..) | ty::Error(_) => { + // By the time this code runs, all type variables ought to + // be fully resolved. + return Err(NoSolution); + } + } + + Ok(()) +} diff --git a/compiler/rustc_trait_selection/src/traits/query/normalize.rs b/compiler/rustc_trait_selection/src/traits/query/normalize.rs index a986a9b6a..8bf934cb7 100644 --- a/compiler/rustc_trait_selection/src/traits/query/normalize.rs +++ b/compiler/rustc_trait_selection/src/traits/query/normalize.rs @@ -257,11 +257,11 @@ impl<'cx, 'tcx> FallibleTypeFolder<TyCtxt<'tcx>> for QueryNormalizer<'cx, 'tcx> ty::Opaque => ty.try_super_fold_with(self)?, - ty::Projection => { + ty::Projection | ty::Inherent => { // See note in `rustc_trait_selection::traits::project` - let tcx = self.infcx.tcx; let infcx = self.infcx; + let tcx = infcx.tcx; // Just an optimization: When we don't have escaping bound vars, // we don't need to replace them with placeholders. let (data, maps) = if data.has_escaping_bound_vars() { @@ -276,12 +276,15 @@ impl<'cx, 'tcx> FallibleTypeFolder<TyCtxt<'tcx>> for QueryNormalizer<'cx, 'tcx> let mut orig_values = OriginalQueryValues::default(); // HACK(matthewjasper) `'static` is special-cased in selection, // so we cannot canonicalize it. - let c_data = self - .infcx + let c_data = infcx .canonicalize_query_keep_static(self.param_env.and(data), &mut orig_values); debug!("QueryNormalizer: c_data = {:#?}", c_data); debug!("QueryNormalizer: orig_values = {:#?}", orig_values); - let result = tcx.normalize_projection_ty(c_data)?; + let result = match kind { + ty::Projection => tcx.normalize_projection_ty(c_data), + ty::Inherent => tcx.normalize_inherent_projection_ty(c_data), + _ => unreachable!(), + }?; // We don't expect ambiguity. if result.is_ambiguous() { // Rustdoc normalizes possibly not well-formed types, so only @@ -294,8 +297,8 @@ impl<'cx, 'tcx> FallibleTypeFolder<TyCtxt<'tcx>> for QueryNormalizer<'cx, 'tcx> } return Err(NoSolution); } - let InferOk { value: result, obligations } = - self.infcx.instantiate_query_response_and_region_obligations( + let InferOk { value: result, obligations } = infcx + .instantiate_query_response_and_region_obligations( self.cause, self.param_env, &orig_values, diff --git a/compiler/rustc_trait_selection/src/traits/query/type_op/ascribe_user_type.rs b/compiler/rustc_trait_selection/src/traits/query/type_op/ascribe_user_type.rs index e6db96c9e..01d7a1e79 100644 --- a/compiler/rustc_trait_selection/src/traits/query/type_op/ascribe_user_type.rs +++ b/compiler/rustc_trait_selection/src/traits/query/type_op/ascribe_user_type.rs @@ -1,8 +1,13 @@ use crate::infer::canonical::{Canonical, CanonicalQueryResponse}; -use crate::traits::query::Fallible; -use rustc_middle::ty::{ParamEnvAnd, TyCtxt}; +use crate::traits::ObligationCtxt; +use rustc_hir::def_id::{DefId, CRATE_DEF_ID}; +use rustc_infer::traits::Obligation; +use rustc_middle::traits::query::NoSolution; +use rustc_middle::traits::{ObligationCause, ObligationCauseCode}; +use rustc_middle::ty::{self, ParamEnvAnd, Ty, TyCtxt, UserSelfTy, UserSubsts, UserType}; pub use rustc_middle::traits::query::type_op::AscribeUserType; +use rustc_span::{Span, DUMMY_SP}; impl<'tcx> super::QueryTypeOp<'tcx> for AscribeUserType<'tcx> { type QueryResponse = (); @@ -17,7 +22,119 @@ impl<'tcx> super::QueryTypeOp<'tcx> for AscribeUserType<'tcx> { fn perform_query( tcx: TyCtxt<'tcx>, canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Self>>, - ) -> Fallible<CanonicalQueryResponse<'tcx, ()>> { + ) -> Result<CanonicalQueryResponse<'tcx, ()>, NoSolution> { tcx.type_op_ascribe_user_type(canonicalized) } + + fn perform_locally_in_new_solver( + ocx: &ObligationCtxt<'_, 'tcx>, + key: ParamEnvAnd<'tcx, Self>, + ) -> Result<Self::QueryResponse, NoSolution> { + type_op_ascribe_user_type_with_span(ocx, key, None) + } +} + +/// The core of the `type_op_ascribe_user_type` query: for diagnostics purposes in NLL HRTB errors, +/// this query can be re-run to better track the span of the obligation cause, and improve the error +/// message. Do not call directly unless you're in that very specific context. +pub fn type_op_ascribe_user_type_with_span<'tcx>( + ocx: &ObligationCtxt<'_, 'tcx>, + key: ParamEnvAnd<'tcx, AscribeUserType<'tcx>>, + span: Option<Span>, +) -> Result<(), NoSolution> { + let (param_env, AscribeUserType { mir_ty, user_ty }) = key.into_parts(); + debug!("type_op_ascribe_user_type: mir_ty={:?} user_ty={:?}", mir_ty, user_ty); + let span = span.unwrap_or(DUMMY_SP); + match user_ty { + UserType::Ty(user_ty) => relate_mir_and_user_ty(ocx, param_env, span, mir_ty, user_ty)?, + UserType::TypeOf(def_id, user_substs) => { + relate_mir_and_user_substs(ocx, param_env, span, mir_ty, def_id, user_substs)? + } + }; + Ok(()) +} + +#[instrument(level = "debug", skip(ocx, param_env, span))] +fn relate_mir_and_user_ty<'tcx>( + ocx: &ObligationCtxt<'_, 'tcx>, + param_env: ty::ParamEnv<'tcx>, + span: Span, + mir_ty: Ty<'tcx>, + user_ty: Ty<'tcx>, +) -> Result<(), NoSolution> { + let cause = ObligationCause::dummy_with_span(span); + let user_ty = ocx.normalize(&cause, param_env, user_ty); + ocx.eq(&cause, param_env, mir_ty, user_ty)?; + + // FIXME(#104764): We should check well-formedness before normalization. + let predicate = ty::Binder::dummy(ty::PredicateKind::WellFormed(user_ty.into())); + ocx.register_obligation(Obligation::new(ocx.infcx.tcx, cause, param_env, predicate)); + Ok(()) +} + +#[instrument(level = "debug", skip(ocx, param_env, span))] +fn relate_mir_and_user_substs<'tcx>( + ocx: &ObligationCtxt<'_, 'tcx>, + param_env: ty::ParamEnv<'tcx>, + span: Span, + mir_ty: Ty<'tcx>, + def_id: DefId, + user_substs: UserSubsts<'tcx>, +) -> Result<(), NoSolution> { + let param_env = param_env.without_const(); + let UserSubsts { user_self_ty, substs } = user_substs; + let tcx = ocx.infcx.tcx; + let cause = ObligationCause::dummy_with_span(span); + + let ty = tcx.type_of(def_id).subst(tcx, substs); + let ty = ocx.normalize(&cause, param_env, ty); + debug!("relate_type_and_user_type: ty of def-id is {:?}", ty); + + ocx.eq(&cause, param_env, mir_ty, ty)?; + + // Prove the predicates coming along with `def_id`. + // + // Also, normalize the `instantiated_predicates` + // because otherwise we wind up with duplicate "type + // outlives" error messages. + let instantiated_predicates = tcx.predicates_of(def_id).instantiate(tcx, substs); + + debug!(?instantiated_predicates); + for (instantiated_predicate, predicate_span) in instantiated_predicates { + let span = if span == DUMMY_SP { predicate_span } else { span }; + let cause = ObligationCause::new( + span, + CRATE_DEF_ID, + ObligationCauseCode::AscribeUserTypeProvePredicate(predicate_span), + ); + let instantiated_predicate = + ocx.normalize(&cause.clone(), param_env, instantiated_predicate); + + ocx.register_obligation(Obligation::new(tcx, cause, param_env, instantiated_predicate)); + } + + if let Some(UserSelfTy { impl_def_id, self_ty }) = user_self_ty { + let self_ty = ocx.normalize(&cause, param_env, self_ty); + let impl_self_ty = tcx.type_of(impl_def_id).subst(tcx, substs); + let impl_self_ty = ocx.normalize(&cause, param_env, impl_self_ty); + + ocx.eq(&cause, param_env, self_ty, impl_self_ty)?; + let predicate = ty::Binder::dummy(ty::PredicateKind::WellFormed(impl_self_ty.into())); + ocx.register_obligation(Obligation::new(tcx, cause.clone(), param_env, predicate)); + } + + // In addition to proving the predicates, we have to + // prove that `ty` is well-formed -- this is because + // the WF of `ty` is predicated on the substs being + // well-formed, and we haven't proven *that*. We don't + // want to prove the WF of types from `substs` directly because they + // haven't been normalized. + // + // FIXME(nmatsakis): Well, perhaps we should normalize + // them? This would only be relevant if some input + // type were ill-formed but did not appear in `ty`, + // which...could happen with normalization... + let predicate = ty::Binder::dummy(ty::PredicateKind::WellFormed(ty.into())); + ocx.register_obligation(Obligation::new(tcx, cause, param_env, predicate)); + Ok(()) } diff --git a/compiler/rustc_trait_selection/src/traits/query/type_op/custom.rs b/compiler/rustc_trait_selection/src/traits/query/type_op/custom.rs index 8f1b05c11..6d8d2103f 100644 --- a/compiler/rustc_trait_selection/src/traits/query/type_op/custom.rs +++ b/compiler/rustc_trait_selection/src/traits/query/type_op/custom.rs @@ -1,32 +1,32 @@ use crate::infer::canonical::query_response; -use crate::infer::{InferCtxt, InferOk}; +use crate::infer::InferCtxt; use crate::traits::query::type_op::TypeOpOutput; -use crate::traits::query::Fallible; use crate::traits::ObligationCtxt; +use rustc_errors::ErrorGuaranteed; use rustc_infer::infer::region_constraints::RegionConstraintData; +use rustc_middle::traits::query::NoSolution; use rustc_span::source_map::DUMMY_SP; +use rustc_span::Span; use std::fmt; -pub struct CustomTypeOp<F, G> { +pub struct CustomTypeOp<F> { closure: F, - description: G, + description: &'static str, } -impl<F, G> CustomTypeOp<F, G> { - pub fn new<'tcx, R>(closure: F, description: G) -> Self +impl<F> CustomTypeOp<F> { + pub fn new<'tcx, R>(closure: F, description: &'static str) -> Self where - F: FnOnce(&InferCtxt<'tcx>) -> Fallible<InferOk<'tcx, R>>, - G: Fn() -> String, + F: FnOnce(&ObligationCtxt<'_, 'tcx>) -> Result<R, NoSolution>, { CustomTypeOp { closure, description } } } -impl<'tcx, F, R: fmt::Debug, G> super::TypeOp<'tcx> for CustomTypeOp<F, G> +impl<'tcx, F, R: fmt::Debug> super::TypeOp<'tcx> for CustomTypeOp<F> where - F: for<'a, 'cx> FnOnce(&'a InferCtxt<'tcx>) -> Fallible<InferOk<'tcx, R>>, - G: Fn() -> String, + F: FnOnce(&ObligationCtxt<'_, 'tcx>) -> Result<R, NoSolution>, { type Output = R; /// We can't do any custom error reporting for `CustomTypeOp`, so @@ -36,21 +36,22 @@ where /// Processes the operation and all resulting obligations, /// returning the final result along with any region constraints /// (they will be given over to the NLL region solver). - fn fully_perform(self, infcx: &InferCtxt<'tcx>) -> Fallible<TypeOpOutput<'tcx, Self>> { + fn fully_perform( + self, + infcx: &InferCtxt<'tcx>, + span: Span, + ) -> Result<TypeOpOutput<'tcx, Self>, ErrorGuaranteed> { if cfg!(debug_assertions) { info!("fully_perform({:?})", self); } - Ok(scrape_region_constraints(infcx, || (self.closure)(infcx))?.0) + Ok(scrape_region_constraints(infcx, self.closure, self.description, span)?.0) } } -impl<F, G> fmt::Debug for CustomTypeOp<F, G> -where - G: Fn() -> String, -{ +impl<F> fmt::Debug for CustomTypeOp<F> { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - write!(f, "{}", (self.description)()) + self.description.fmt(f) } } @@ -58,8 +59,10 @@ where /// constraints that result, creating query-region-constraints. pub fn scrape_region_constraints<'tcx, Op: super::TypeOp<'tcx, Output = R>, R>( infcx: &InferCtxt<'tcx>, - op: impl FnOnce() -> Fallible<InferOk<'tcx, R>>, -) -> Fallible<(TypeOpOutput<'tcx, Op>, RegionConstraintData<'tcx>)> { + op: impl FnOnce(&ObligationCtxt<'_, 'tcx>) -> Result<R, NoSolution>, + name: &'static str, + span: Span, +) -> Result<(TypeOpOutput<'tcx, Op>, RegionConstraintData<'tcx>), ErrorGuaranteed> { // During NLL, we expect that nobody will register region // obligations **except** as part of a custom type op (and, at the // end of each custom type op, we scrape out the region @@ -72,16 +75,21 @@ pub fn scrape_region_constraints<'tcx, Op: super::TypeOp<'tcx, Output = R>, R>( pre_obligations, ); - let InferOk { value, obligations } = infcx.commit_if_ok(|_| op())?; - let ocx = ObligationCtxt::new(infcx); - ocx.register_obligations(obligations); - let errors = ocx.select_all_or_error(); - if !errors.is_empty() { - infcx.tcx.sess.diagnostic().delay_span_bug( - DUMMY_SP, - &format!("errors selecting obligation during MIR typeck: {:?}", errors), - ); - } + let value = infcx.commit_if_ok(|_| { + let ocx = ObligationCtxt::new_in_snapshot(infcx); + let value = op(&ocx).map_err(|_| { + infcx.tcx.sess.delay_span_bug(span, format!("error performing operation: {name}")) + })?; + let errors = ocx.select_all_or_error(); + if errors.is_empty() { + Ok(value) + } else { + Err(infcx.tcx.sess.delay_span_bug( + DUMMY_SP, + format!("errors selecting obligation during MIR typeck: {:?}", errors), + )) + } + })?; let region_obligations = infcx.take_registered_region_obligations(); let region_constraint_data = infcx.take_and_reset_region_constraints(); diff --git a/compiler/rustc_trait_selection/src/traits/query/type_op/eq.rs b/compiler/rustc_trait_selection/src/traits/query/type_op/eq.rs index 8c9b9610c..f65893088 100644 --- a/compiler/rustc_trait_selection/src/traits/query/type_op/eq.rs +++ b/compiler/rustc_trait_selection/src/traits/query/type_op/eq.rs @@ -1,5 +1,7 @@ use crate::infer::canonical::{Canonical, CanonicalQueryResponse}; -use crate::traits::query::Fallible; +use crate::traits::ObligationCtxt; +use rustc_middle::traits::query::NoSolution; +use rustc_middle::traits::ObligationCause; use rustc_middle::ty::{ParamEnvAnd, TyCtxt}; pub use rustc_middle::traits::query::type_op::Eq; @@ -17,7 +19,15 @@ impl<'tcx> super::QueryTypeOp<'tcx> for Eq<'tcx> { fn perform_query( tcx: TyCtxt<'tcx>, canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Self>>, - ) -> Fallible<CanonicalQueryResponse<'tcx, ()>> { + ) -> Result<CanonicalQueryResponse<'tcx, ()>, NoSolution> { tcx.type_op_eq(canonicalized) } + + fn perform_locally_in_new_solver( + ocx: &ObligationCtxt<'_, 'tcx>, + key: ParamEnvAnd<'tcx, Self>, + ) -> Result<Self::QueryResponse, NoSolution> { + ocx.eq(&ObligationCause::dummy(), key.param_env, key.value.a, key.value.b)?; + Ok(()) + } } diff --git a/compiler/rustc_trait_selection/src/traits/query/type_op/implied_outlives_bounds.rs b/compiler/rustc_trait_selection/src/traits/query/type_op/implied_outlives_bounds.rs index 18d7c9b19..9989fc9c4 100644 --- a/compiler/rustc_trait_selection/src/traits/query/type_op/implied_outlives_bounds.rs +++ b/compiler/rustc_trait_selection/src/traits/query/type_op/implied_outlives_bounds.rs @@ -1,7 +1,15 @@ -use crate::infer::canonical::{Canonical, CanonicalQueryResponse}; -use crate::traits::query::Fallible; +use crate::traits::query::NoSolution; +use crate::traits::wf; +use crate::traits::ObligationCtxt; + +use rustc_infer::infer::canonical::Canonical; +use rustc_infer::infer::outlives::components::{push_outlives_components, Component}; use rustc_infer::traits::query::OutlivesBound; -use rustc_middle::ty::{self, ParamEnvAnd, Ty, TyCtxt}; +use rustc_middle::infer::canonical::CanonicalQueryResponse; +use rustc_middle::ty::{self, ParamEnvAnd, Ty, TyCtxt, TypeVisitableExt}; +use rustc_span::def_id::CRATE_DEF_ID; +use rustc_span::source_map::DUMMY_SP; +use smallvec::{smallvec, SmallVec}; #[derive(Copy, Clone, Debug, HashStable, TypeFoldable, TypeVisitable, Lift)] pub struct ImpliedOutlivesBounds<'tcx> { @@ -28,7 +36,7 @@ impl<'tcx> super::QueryTypeOp<'tcx> for ImpliedOutlivesBounds<'tcx> { fn perform_query( tcx: TyCtxt<'tcx>, canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Self>>, - ) -> Fallible<CanonicalQueryResponse<'tcx, Self::QueryResponse>> { + ) -> Result<CanonicalQueryResponse<'tcx, Self::QueryResponse>, NoSolution> { // FIXME this `unchecked_map` is only necessary because the // query is defined as taking a `ParamEnvAnd<Ty>`; it should // take an `ImpliedOutlivesBounds` instead @@ -39,4 +47,169 @@ impl<'tcx> super::QueryTypeOp<'tcx> for ImpliedOutlivesBounds<'tcx> { tcx.implied_outlives_bounds(canonicalized) } + + fn perform_locally_in_new_solver( + ocx: &ObligationCtxt<'_, 'tcx>, + key: ParamEnvAnd<'tcx, Self>, + ) -> Result<Self::QueryResponse, NoSolution> { + compute_implied_outlives_bounds_inner(ocx, key.param_env, key.value.ty) + } +} + +pub fn compute_implied_outlives_bounds_inner<'tcx>( + ocx: &ObligationCtxt<'_, 'tcx>, + param_env: ty::ParamEnv<'tcx>, + ty: Ty<'tcx>, +) -> Result<Vec<OutlivesBound<'tcx>>, NoSolution> { + let tcx = ocx.infcx.tcx; + + // Sometimes when we ask what it takes for T: WF, we get back that + // U: WF is required; in that case, we push U onto this stack and + // process it next. Because the resulting predicates aren't always + // guaranteed to be a subset of the original type, so we need to store the + // WF args we've computed in a set. + let mut checked_wf_args = rustc_data_structures::fx::FxHashSet::default(); + let mut wf_args = vec![ty.into()]; + + let mut outlives_bounds: Vec<ty::OutlivesPredicate<ty::GenericArg<'tcx>, ty::Region<'tcx>>> = + vec![]; + + while let Some(arg) = wf_args.pop() { + if !checked_wf_args.insert(arg) { + continue; + } + + // Compute the obligations for `arg` to be well-formed. If `arg` is + // an unresolved inference variable, just substituted an empty set + // -- because the return type here is going to be things we *add* + // to the environment, it's always ok for this set to be smaller + // than the ultimate set. (Note: normally there won't be + // unresolved inference variables here anyway, but there might be + // during typeck under some circumstances.) + // + // FIXME(@lcnr): It's not really "always fine", having fewer implied + // bounds can be backward incompatible, e.g. #101951 was caused by + // us not dealing with inference vars in `TypeOutlives` predicates. + let obligations = wf::obligations(ocx.infcx, param_env, CRATE_DEF_ID, 0, arg, DUMMY_SP) + .unwrap_or_default(); + + for obligation in obligations { + debug!(?obligation); + assert!(!obligation.has_escaping_bound_vars()); + + // While these predicates should all be implied by other parts of + // the program, they are still relevant as they may constrain + // inference variables, which is necessary to add the correct + // implied bounds in some cases, mostly when dealing with projections. + // + // Another important point here: we only register `Projection` + // predicates, since otherwise we might register outlives + // predicates containing inference variables, and we don't + // learn anything new from those. + if obligation.predicate.has_non_region_infer() { + match obligation.predicate.kind().skip_binder() { + ty::PredicateKind::Clause(ty::Clause::Projection(..)) + | ty::PredicateKind::AliasRelate(..) => { + ocx.register_obligation(obligation.clone()); + } + _ => {} + } + } + + let pred = match obligation.predicate.kind().no_bound_vars() { + None => continue, + Some(pred) => pred, + }; + match pred { + ty::PredicateKind::Clause(ty::Clause::Trait(..)) + // FIXME(const_generics): Make sure that `<'a, 'b, const N: &'a &'b u32>` is sound + // if we ever support that + | ty::PredicateKind::Clause(ty::Clause::ConstArgHasType(..)) + | ty::PredicateKind::Subtype(..) + | ty::PredicateKind::Coerce(..) + | ty::PredicateKind::Clause(ty::Clause::Projection(..)) + | ty::PredicateKind::ClosureKind(..) + | ty::PredicateKind::ObjectSafe(..) + | ty::PredicateKind::ConstEvaluatable(..) + | ty::PredicateKind::ConstEquate(..) + | ty::PredicateKind::Ambiguous + | ty::PredicateKind::AliasRelate(..) + | ty::PredicateKind::TypeWellFormedFromEnv(..) => {} + + // We need to search through *all* WellFormed predicates + ty::PredicateKind::WellFormed(arg) => { + wf_args.push(arg); + } + + // We need to register region relationships + ty::PredicateKind::Clause(ty::Clause::RegionOutlives(ty::OutlivesPredicate( + r_a, + r_b, + ))) => outlives_bounds.push(ty::OutlivesPredicate(r_a.into(), r_b)), + + ty::PredicateKind::Clause(ty::Clause::TypeOutlives(ty::OutlivesPredicate( + ty_a, + r_b, + ))) => outlives_bounds.push(ty::OutlivesPredicate(ty_a.into(), r_b)), + } + } + } + + // This call to `select_all_or_error` is necessary to constrain inference variables, which we + // use further down when computing the implied bounds. + match ocx.select_all_or_error().as_slice() { + [] => (), + _ => return Err(NoSolution), + } + + // We lazily compute the outlives components as + // `select_all_or_error` constrains inference variables. + let implied_bounds = outlives_bounds + .into_iter() + .flat_map(|ty::OutlivesPredicate(a, r_b)| match a.unpack() { + ty::GenericArgKind::Lifetime(r_a) => vec![OutlivesBound::RegionSubRegion(r_b, r_a)], + ty::GenericArgKind::Type(ty_a) => { + let ty_a = ocx.infcx.resolve_vars_if_possible(ty_a); + let mut components = smallvec![]; + push_outlives_components(tcx, ty_a, &mut components); + implied_bounds_from_components(r_b, components) + } + ty::GenericArgKind::Const(_) => unreachable!(), + }) + .collect(); + + Ok(implied_bounds) +} + +/// When we have an implied bound that `T: 'a`, we can further break +/// this down to determine what relationships would have to hold for +/// `T: 'a` to hold. We get to assume that the caller has validated +/// those relationships. +fn implied_bounds_from_components<'tcx>( + sub_region: ty::Region<'tcx>, + sup_components: SmallVec<[Component<'tcx>; 4]>, +) -> Vec<OutlivesBound<'tcx>> { + sup_components + .into_iter() + .filter_map(|component| { + match component { + Component::Region(r) => Some(OutlivesBound::RegionSubRegion(sub_region, r)), + Component::Param(p) => Some(OutlivesBound::RegionSubParam(sub_region, p)), + Component::Alias(p) => Some(OutlivesBound::RegionSubAlias(sub_region, p)), + Component::EscapingAlias(_) => + // If the projection has escaping regions, don't + // try to infer any implied bounds even for its + // free components. This is conservative, because + // the caller will still have to prove that those + // free components outlive `sub_region`. But the + // idea is that the WAY that the caller proves + // that may change in the future and we want to + // give ourselves room to get smarter here. + { + None + } + Component::UnresolvedInferenceVariable(..) => None, + } + }) + .collect() } diff --git a/compiler/rustc_trait_selection/src/traits/query/type_op/mod.rs b/compiler/rustc_trait_selection/src/traits/query/type_op/mod.rs index 9e8bc8bce..642fdec2d 100644 --- a/compiler/rustc_trait_selection/src/traits/query/type_op/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/query/type_op/mod.rs @@ -2,13 +2,14 @@ use crate::infer::canonical::{ Canonical, CanonicalQueryResponse, OriginalQueryValues, QueryRegionConstraints, }; use crate::infer::{InferCtxt, InferOk}; -use crate::traits::query::Fallible; -use crate::traits::ObligationCause; +use crate::traits::{ObligationCause, ObligationCtxt}; +use rustc_errors::ErrorGuaranteed; use rustc_infer::infer::canonical::Certainty; -use rustc_infer::traits::query::NoSolution; use rustc_infer::traits::PredicateObligations; +use rustc_middle::traits::query::NoSolution; use rustc_middle::ty::fold::TypeFoldable; use rustc_middle::ty::{ParamEnvAnd, TyCtxt}; +use rustc_span::Span; use std::fmt; pub mod ascribe_user_type; @@ -22,6 +23,8 @@ pub mod subtype; pub use rustc_middle::traits::query::type_op::*; +use self::custom::scrape_region_constraints; + /// "Type ops" are used in NLL to perform some particular action and /// extract out the resulting region constraints (or an error if it /// cannot be completed). @@ -32,7 +35,11 @@ pub trait TypeOp<'tcx>: Sized + fmt::Debug { /// Processes the operation and all resulting obligations, /// returning the final result along with any region constraints /// (they will be given over to the NLL region solver). - fn fully_perform(self, infcx: &InferCtxt<'tcx>) -> Fallible<TypeOpOutput<'tcx, Self>>; + fn fully_perform( + self, + infcx: &InferCtxt<'tcx>, + span: Span, + ) -> Result<TypeOpOutput<'tcx, Self>, ErrorGuaranteed>; } /// The output from performing a type op @@ -74,18 +81,32 @@ pub trait QueryTypeOp<'tcx>: fmt::Debug + Copy + TypeFoldable<TyCtxt<'tcx>> + 't fn perform_query( tcx: TyCtxt<'tcx>, canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Self>>, - ) -> Fallible<CanonicalQueryResponse<'tcx, Self::QueryResponse>>; + ) -> Result<CanonicalQueryResponse<'tcx, Self::QueryResponse>, NoSolution>; + + /// In the new trait solver, we already do caching in the solver itself, + /// so there's no need to canonicalize and cache via the query system. + /// Additionally, even if we were to canonicalize, we'd still need to + /// make sure to feed it predefined opaque types and the defining anchor + /// and that would require duplicating all of the tcx queries. Instead, + /// just perform these ops locally. + fn perform_locally_in_new_solver( + ocx: &ObligationCtxt<'_, 'tcx>, + key: ParamEnvAnd<'tcx, Self>, + ) -> Result<Self::QueryResponse, NoSolution>; fn fully_perform_into( query_key: ParamEnvAnd<'tcx, Self>, infcx: &InferCtxt<'tcx>, output_query_region_constraints: &mut QueryRegionConstraints<'tcx>, - ) -> Fallible<( - Self::QueryResponse, - Option<Canonical<'tcx, ParamEnvAnd<'tcx, Self>>>, - PredicateObligations<'tcx>, - Certainty, - )> { + ) -> Result< + ( + Self::QueryResponse, + Option<Canonical<'tcx, ParamEnvAnd<'tcx, Self>>>, + PredicateObligations<'tcx>, + Certainty, + ), + NoSolution, + > { if let Some(result) = QueryTypeOp::try_fast_path(infcx.tcx, &query_key) { return Ok((result, None, vec![], Certainty::Proven)); } @@ -120,10 +141,26 @@ where type Output = Q::QueryResponse; type ErrorInfo = Canonical<'tcx, ParamEnvAnd<'tcx, Q>>; - fn fully_perform(self, infcx: &InferCtxt<'tcx>) -> Fallible<TypeOpOutput<'tcx, Self>> { + fn fully_perform( + self, + infcx: &InferCtxt<'tcx>, + span: Span, + ) -> Result<TypeOpOutput<'tcx, Self>, ErrorGuaranteed> { + if infcx.tcx.trait_solver_next() { + return Ok(scrape_region_constraints( + infcx, + |ocx| QueryTypeOp::perform_locally_in_new_solver(ocx, self), + "query type op", + span, + )? + .0); + } + let mut region_constraints = QueryRegionConstraints::default(); let (output, error_info, mut obligations, _) = - Q::fully_perform_into(self, infcx, &mut region_constraints)?; + Q::fully_perform_into(self, infcx, &mut region_constraints).map_err(|_| { + infcx.tcx.sess.delay_span_bug(span, format!("error performing {self:?}")) + })?; // Typically, instantiating NLL query results does not // create obligations. However, in some cases there @@ -151,7 +188,10 @@ where } } if !progress { - return Err(NoSolution); + return Err(infcx.tcx.sess.delay_span_bug( + span, + format!("ambiguity processing {obligations:?} from {self:?}"), + )); } } diff --git a/compiler/rustc_trait_selection/src/traits/query/type_op/normalize.rs b/compiler/rustc_trait_selection/src/traits/query/type_op/normalize.rs index 5b216c076..57ca14aa4 100644 --- a/compiler/rustc_trait_selection/src/traits/query/type_op/normalize.rs +++ b/compiler/rustc_trait_selection/src/traits/query/type_op/normalize.rs @@ -1,5 +1,7 @@ use crate::infer::canonical::{Canonical, CanonicalQueryResponse}; -use crate::traits::query::Fallible; +use crate::traits::ObligationCtxt; +use rustc_middle::traits::query::NoSolution; +use rustc_middle::traits::ObligationCause; use rustc_middle::ty::fold::TypeFoldable; use rustc_middle::ty::{self, Lift, ParamEnvAnd, Ty, TyCtxt, TypeVisitableExt}; use std::fmt; @@ -19,23 +21,31 @@ where fn perform_query( tcx: TyCtxt<'tcx>, canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Self>>, - ) -> Fallible<CanonicalQueryResponse<'tcx, Self::QueryResponse>> { + ) -> Result<CanonicalQueryResponse<'tcx, Self::QueryResponse>, NoSolution> { T::type_op_method(tcx, canonicalized) } + + fn perform_locally_in_new_solver( + ocx: &ObligationCtxt<'_, 'tcx>, + key: ParamEnvAnd<'tcx, Self>, + ) -> Result<Self::QueryResponse, NoSolution> { + // FIXME(-Ztrait-solver=next): shouldn't be using old normalizer + Ok(ocx.normalize(&ObligationCause::dummy(), key.param_env, key.value.value)) + } } pub trait Normalizable<'tcx>: fmt::Debug + TypeFoldable<TyCtxt<'tcx>> + Lift<'tcx> + Copy { fn type_op_method( tcx: TyCtxt<'tcx>, canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Normalize<Self>>>, - ) -> Fallible<CanonicalQueryResponse<'tcx, Self>>; + ) -> Result<CanonicalQueryResponse<'tcx, Self>, NoSolution>; } impl<'tcx> Normalizable<'tcx> for Ty<'tcx> { fn type_op_method( tcx: TyCtxt<'tcx>, canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Normalize<Self>>>, - ) -> Fallible<CanonicalQueryResponse<'tcx, Self>> { + ) -> Result<CanonicalQueryResponse<'tcx, Self>, NoSolution> { tcx.type_op_normalize_ty(canonicalized) } } @@ -44,7 +54,7 @@ impl<'tcx> Normalizable<'tcx> for ty::Predicate<'tcx> { fn type_op_method( tcx: TyCtxt<'tcx>, canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Normalize<Self>>>, - ) -> Fallible<CanonicalQueryResponse<'tcx, Self>> { + ) -> Result<CanonicalQueryResponse<'tcx, Self>, NoSolution> { tcx.type_op_normalize_predicate(canonicalized) } } @@ -53,7 +63,7 @@ impl<'tcx> Normalizable<'tcx> for ty::PolyFnSig<'tcx> { fn type_op_method( tcx: TyCtxt<'tcx>, canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Normalize<Self>>>, - ) -> Fallible<CanonicalQueryResponse<'tcx, Self>> { + ) -> Result<CanonicalQueryResponse<'tcx, Self>, NoSolution> { tcx.type_op_normalize_poly_fn_sig(canonicalized) } } @@ -62,7 +72,7 @@ impl<'tcx> Normalizable<'tcx> for ty::FnSig<'tcx> { fn type_op_method( tcx: TyCtxt<'tcx>, canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Normalize<Self>>>, - ) -> Fallible<CanonicalQueryResponse<'tcx, Self>> { + ) -> Result<CanonicalQueryResponse<'tcx, Self>, NoSolution> { tcx.type_op_normalize_fn_sig(canonicalized) } } diff --git a/compiler/rustc_trait_selection/src/traits/query/type_op/outlives.rs b/compiler/rustc_trait_selection/src/traits/query/type_op/outlives.rs index 21ef4e24f..988942633 100644 --- a/compiler/rustc_trait_selection/src/traits/query/type_op/outlives.rs +++ b/compiler/rustc_trait_selection/src/traits/query/type_op/outlives.rs @@ -1,6 +1,9 @@ use crate::infer::canonical::{Canonical, CanonicalQueryResponse}; -use crate::traits::query::dropck_outlives::{trivial_dropck_outlives, DropckOutlivesResult}; -use crate::traits::query::Fallible; +use crate::traits::query::dropck_outlives::{ + compute_dropck_outlives_inner, trivial_dropck_outlives, +}; +use crate::traits::ObligationCtxt; +use rustc_middle::traits::query::{DropckOutlivesResult, NoSolution}; use rustc_middle::ty::{ParamEnvAnd, Ty, TyCtxt}; #[derive(Copy, Clone, Debug, HashStable, TypeFoldable, TypeVisitable, Lift)] @@ -27,7 +30,7 @@ impl<'tcx> super::QueryTypeOp<'tcx> for DropckOutlives<'tcx> { fn perform_query( tcx: TyCtxt<'tcx>, canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Self>>, - ) -> Fallible<CanonicalQueryResponse<'tcx, Self::QueryResponse>> { + ) -> Result<CanonicalQueryResponse<'tcx, Self::QueryResponse>, NoSolution> { // Subtle: note that we are not invoking // `infcx.at(...).dropck_outlives(...)` here, but rather the // underlying `dropck_outlives` query. This same underlying @@ -48,4 +51,11 @@ impl<'tcx> super::QueryTypeOp<'tcx> for DropckOutlives<'tcx> { tcx.dropck_outlives(canonicalized) } + + fn perform_locally_in_new_solver( + ocx: &ObligationCtxt<'_, 'tcx>, + key: ParamEnvAnd<'tcx, Self>, + ) -> Result<Self::QueryResponse, NoSolution> { + compute_dropck_outlives_inner(ocx, key.param_env.and(key.value.dropped_ty)) + } } diff --git a/compiler/rustc_trait_selection/src/traits/query/type_op/prove_predicate.rs b/compiler/rustc_trait_selection/src/traits/query/type_op/prove_predicate.rs index b63da28e2..47850bc33 100644 --- a/compiler/rustc_trait_selection/src/traits/query/type_op/prove_predicate.rs +++ b/compiler/rustc_trait_selection/src/traits/query/type_op/prove_predicate.rs @@ -1,5 +1,8 @@ use crate::infer::canonical::{Canonical, CanonicalQueryResponse}; -use crate::traits::query::Fallible; +use crate::traits::ObligationCtxt; +use rustc_infer::traits::Obligation; +use rustc_middle::traits::query::NoSolution; +use rustc_middle::traits::ObligationCause; use rustc_middle::ty::{self, ParamEnvAnd, TyCtxt}; pub use rustc_middle::traits::query::type_op::ProvePredicate; @@ -32,14 +35,21 @@ impl<'tcx> super::QueryTypeOp<'tcx> for ProvePredicate<'tcx> { fn perform_query( tcx: TyCtxt<'tcx>, - mut canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Self>>, - ) -> Fallible<CanonicalQueryResponse<'tcx, ()>> { - match canonicalized.value.value.predicate.kind().skip_binder() { - ty::PredicateKind::Clause(ty::Clause::Trait(pred)) => { - canonicalized.value.param_env.remap_constness_with(pred.constness); - } - _ => canonicalized.value.param_env = canonicalized.value.param_env.without_const(), - } + canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Self>>, + ) -> Result<CanonicalQueryResponse<'tcx, ()>, NoSolution> { tcx.type_op_prove_predicate(canonicalized) } + + fn perform_locally_in_new_solver( + ocx: &ObligationCtxt<'_, 'tcx>, + key: ParamEnvAnd<'tcx, Self>, + ) -> Result<Self::QueryResponse, NoSolution> { + ocx.register_obligation(Obligation::new( + ocx.infcx.tcx, + ObligationCause::dummy(), + key.param_env, + key.value.predicate, + )); + Ok(()) + } } diff --git a/compiler/rustc_trait_selection/src/traits/query/type_op/subtype.rs b/compiler/rustc_trait_selection/src/traits/query/type_op/subtype.rs index c51292eba..10976d5cd 100644 --- a/compiler/rustc_trait_selection/src/traits/query/type_op/subtype.rs +++ b/compiler/rustc_trait_selection/src/traits/query/type_op/subtype.rs @@ -1,5 +1,7 @@ use crate::infer::canonical::{Canonical, CanonicalQueryResponse}; -use crate::traits::query::Fallible; +use crate::traits::ObligationCtxt; +use rustc_middle::traits::query::NoSolution; +use rustc_middle::traits::ObligationCause; use rustc_middle::ty::{ParamEnvAnd, TyCtxt}; pub use rustc_middle::traits::query::type_op::Subtype; @@ -14,7 +16,15 @@ impl<'tcx> super::QueryTypeOp<'tcx> for Subtype<'tcx> { fn perform_query( tcx: TyCtxt<'tcx>, canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Self>>, - ) -> Fallible<CanonicalQueryResponse<'tcx, ()>> { + ) -> Result<CanonicalQueryResponse<'tcx, ()>, NoSolution> { tcx.type_op_subtype(canonicalized) } + + fn perform_locally_in_new_solver( + ocx: &ObligationCtxt<'_, 'tcx>, + key: ParamEnvAnd<'tcx, Self>, + ) -> Result<Self::QueryResponse, NoSolution> { + ocx.sub(&ObligationCause::dummy(), key.param_env, key.value.sub, key.value.sup)?; + Ok(()) + } } diff --git a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs index 1f5bbc178..8bc82b9f5 100644 --- a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs +++ b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs @@ -11,7 +11,7 @@ use hir::LangItem; use rustc_hir as hir; use rustc_infer::traits::ObligationCause; use rustc_infer::traits::{Obligation, SelectionError, TraitObligation}; -use rustc_middle::ty::fast_reject::{DeepRejectCtxt, TreatParams, TreatProjections}; +use rustc_middle::ty::fast_reject::{DeepRejectCtxt, TreatParams}; use rustc_middle::ty::{self, Ty, TypeVisitableExt}; use crate::traits; @@ -57,6 +57,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { if obligation.polarity() == ty::ImplPolarity::Negative { self.assemble_candidates_for_trait_alias(obligation, &mut candidates); self.assemble_candidates_from_impls(obligation, &mut candidates); + self.assemble_candidates_from_caller_bounds(stack, &mut candidates)?; } else { self.assemble_candidates_for_trait_alias(obligation, &mut candidates); @@ -142,7 +143,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { // Before we go into the whole placeholder thing, just // quickly check if the self-type is a projection at all. match obligation.predicate.skip_binder().trait_ref.self_ty().kind() { - ty::Alias(..) => {} + // Excluding IATs here as they don't have meaningful item bounds. + ty::Alias(ty::Projection | ty::Opaque, _) => {} ty::Infer(ty::TyVar(_)) => { span_bug!( obligation.cause.span, @@ -187,6 +189,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { // Keep only those bounds which may apply, and propagate overflow if it occurs. for bound in matching_bounds { + if bound.skip_binder().polarity != stack.obligation.predicate.skip_binder().polarity { + continue; + } + // FIXME(oli-obk): it is suspicious that we are dropping the constness and // polarity here. let wc = self.where_clause_may_apply(stack, bound.map_bound(|t| t.trait_ref))?; @@ -454,7 +460,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { obligation.param_env, self.tcx().mk_predicate(obligation.predicate.map_bound(|mut pred| { pred.trait_ref = - self.tcx().mk_trait_ref(fn_ptr_trait, [pred.trait_ref.self_ty()]); + ty::TraitRef::new(self.tcx(), fn_ptr_trait, [pred.trait_ref.self_ty()]); ty::PredicateKind::Clause(ty::Clause::Trait(pred)) })), ); @@ -493,7 +499,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { // this trait and type. } ty::Param(..) - | ty::Alias(ty::Projection, ..) + | ty::Alias(ty::Projection | ty::Inherent, ..) | ty::Placeholder(..) | ty::Bound(..) => { // In these cases, we don't know what the actual @@ -629,7 +635,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { } // <ty as Deref> - let trait_ref = tcx.mk_trait_ref(tcx.lang_items().deref_trait()?, [ty]); + let trait_ref = ty::TraitRef::new(tcx, tcx.lang_items().deref_trait()?, [ty]); let obligation = traits::Obligation::new(tcx, cause.clone(), param_env, ty::Binder::dummy(trait_ref)); @@ -775,7 +781,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { obligation: &TraitObligation<'tcx>, candidates: &mut SelectionCandidateSet<'tcx>, ) { - if obligation.has_non_region_param() { + if obligation.predicate.has_non_region_param() { return; } @@ -875,12 +881,24 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { } ty::Adt(..) => { - // Find a custom `impl Drop` impl, if it exists - let relevant_impl = self.tcx().find_map_relevant_impl( + let mut relevant_impl = None; + self.tcx().for_each_relevant_impl( self.tcx().require_lang_item(LangItem::Drop, None), obligation.predicate.skip_binder().trait_ref.self_ty(), - TreatProjections::ForLookup, - Some, + |impl_def_id| { + if let Some(old_impl_def_id) = relevant_impl { + self.tcx() + .sess + .struct_span_err( + self.tcx().def_span(impl_def_id), + "multiple drop impls found", + ) + .span_note(self.tcx().def_span(old_impl_def_id), "other impl here") + .delay_as_bug(); + } + + relevant_impl = Some(impl_def_id); + }, ); if let Some(impl_def_id) = relevant_impl { @@ -949,16 +967,18 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { ) { // The regions of a type don't affect the size of the type let tcx = self.tcx(); - let self_ty = - tcx.erase_regions(tcx.erase_late_bound_regions(obligation.predicate.self_ty())); - + let self_ty = tcx.erase_late_bound_regions(obligation.predicate.self_ty()); + // We should erase regions from both the param-env and type, since both + // may have infer regions. Specifically, after canonicalizing and instantiating, + // early bound regions turn into region vars in both the new and old solver. + let key = tcx.erase_regions(obligation.param_env.and(self_ty)); // But if there are inference variables, we have to wait until it's resolved. - if self_ty.has_non_region_infer() { + if key.has_non_region_infer() { candidates.ambiguous = true; return; } - if let Ok(layout) = tcx.layout_of(obligation.param_env.and(self_ty)) + if let Ok(layout) = tcx.layout_of(key) && layout.layout.is_pointer_like(&tcx.data_layout) { candidates.vec.push(BuiltinCandidate { has_nested: false }); diff --git a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs index 88121f865..0d9f55d4c 100644 --- a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs +++ b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs @@ -10,6 +10,7 @@ use rustc_data_structures::stack::ensure_sufficient_stack; use rustc_hir::lang_items::LangItem; use rustc_infer::infer::LateBoundRegionConversionTime::HigherRankedType; use rustc_infer::infer::{DefineOpaqueTypes, InferOk}; +use rustc_middle::traits::SelectionOutputTypeParameterMismatch; use rustc_middle::ty::{ self, Binder, GenericParamDefKind, InternalSubsts, SubstsRef, ToPolyTraitRef, ToPredicate, TraitRef, Ty, TyCtxt, TypeVisitableExt, @@ -28,9 +29,9 @@ use crate::traits::{ ImplSourceAutoImplData, ImplSourceBuiltinData, ImplSourceClosureData, ImplSourceConstDestructData, ImplSourceFnPointerData, ImplSourceFutureData, ImplSourceGeneratorData, ImplSourceObjectData, ImplSourceTraitAliasData, - ImplSourceTraitUpcastingData, ImplSourceUserDefinedData, Normalized, ObjectCastObligation, - Obligation, ObligationCause, OutputTypeParameterMismatch, PredicateObligation, Selection, - SelectionError, TraitNotObjectSafe, TraitObligation, Unimplemented, + ImplSourceTraitUpcastingData, ImplSourceUserDefinedData, Normalized, Obligation, + ObligationCause, OutputTypeParameterMismatch, PredicateObligation, Selection, SelectionError, + TraitNotObjectSafe, TraitObligation, Unimplemented, }; use super::BuiltinImplConditions; @@ -161,7 +162,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { let placeholder_self_ty = placeholder_trait_predicate.self_ty(); let placeholder_trait_predicate = ty::Binder::dummy(placeholder_trait_predicate); let (def_id, substs) = match *placeholder_self_ty.kind() { - ty::Alias(_, ty::AliasTy { def_id, substs, .. }) => (def_id, substs), + // Excluding IATs here as they don't have meaningful item bounds. + ty::Alias(ty::Projection | ty::Opaque, ty::AliasTy { def_id, substs, .. }) => { + (def_id, substs) + } _ => bug!("projection candidate for unexpected type: {:?}", placeholder_self_ty), }; @@ -281,33 +285,35 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { ) -> Result<ImplSourceBuiltinData<PredicateObligation<'tcx>>, SelectionError<'tcx>> { debug!(?obligation, "confirm_transmutability_candidate"); - let predicate = obligation.predicate; - - let type_at = |i| predicate.map_bound(|p| p.trait_ref.substs.type_at(i)); - let const_at = |i| predicate.skip_binder().trait_ref.substs.const_at(i); - - let src_and_dst = predicate.map_bound(|p| rustc_transmute::Types { - dst: p.trait_ref.substs.type_at(0), - src: p.trait_ref.substs.type_at(1), - }); - - let scope = type_at(2).skip_binder(); - - let Some(assume) = - rustc_transmute::Assume::from_const(self.infcx.tcx, obligation.param_env, const_at(3)) else { - return Err(Unimplemented); - }; + // We erase regions here because transmutability calls layout queries, + // which does not handle inference regions and doesn't particularly + // care about other regions. Erasing late-bound regions is equivalent + // to instantiating the binder with placeholders then erasing those + // placeholder regions. + let predicate = + self.tcx().erase_regions(self.tcx().erase_late_bound_regions(obligation.predicate)); - let cause = obligation.cause.clone(); + let Some(assume) = rustc_transmute::Assume::from_const( + self.infcx.tcx, + obligation.param_env, + predicate.trait_ref.substs.const_at(3) + ) else { + return Err(Unimplemented); + }; let mut transmute_env = rustc_transmute::TransmuteTypeEnv::new(self.infcx); - - let maybe_transmutable = transmute_env.is_transmutable(cause, src_and_dst, scope, assume); - - use rustc_transmute::Answer; + let maybe_transmutable = transmute_env.is_transmutable( + obligation.cause.clone(), + rustc_transmute::Types { + dst: predicate.trait_ref.substs.type_at(0), + src: predicate.trait_ref.substs.type_at(1), + }, + predicate.trait_ref.substs.type_at(2), + assume, + ); match maybe_transmutable { - Answer::Yes => Ok(ImplSourceBuiltinData { nested: vec![] }), + rustc_transmute::Answer::Yes => Ok(ImplSourceBuiltinData { nested: vec![] }), _ => Err(Unimplemented), } } @@ -650,8 +656,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { output_ty, &mut nested, ); - let tr = - ty::Binder::dummy(self.tcx().at(cause.span).mk_trait_ref(LangItem::Sized, [output_ty])); + let tr = ty::TraitRef::from_lang_item(self.tcx(), LangItem::Sized, cause.span, [output_ty]); nested.push(Obligation::new(self.infcx.tcx, cause, obligation.param_env, tr)); Ok(ImplSourceFnPointerData { fn_ty: self_ty, nested }) @@ -816,7 +821,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { fn confirm_poly_trait_refs( &mut self, obligation: &TraitObligation<'tcx>, - expected_trait_ref: ty::PolyTraitRef<'tcx>, + self_ty_trait_ref: ty::PolyTraitRef<'tcx>, ) -> Result<Vec<PredicateObligation<'tcx>>, SelectionError<'tcx>> { let obligation_trait_ref = obligation.predicate.to_poly_trait_ref(); // Normalize the obligation and expected trait refs together, because why not @@ -827,7 +832,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { obligation.param_env, obligation.cause.clone(), obligation.recursion_depth + 1, - (obligation_trait_ref, expected_trait_ref), + (obligation_trait_ref, self_ty_trait_ref), ) }); @@ -839,7 +844,13 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { obligations.extend(nested); obligations }) - .map_err(|e| OutputTypeParameterMismatch(expected_trait_ref, obligation_trait_ref, e)) + .map_err(|terr| { + OutputTypeParameterMismatch(Box::new(SelectionOutputTypeParameterMismatch { + expected_trait_ref: obligation_trait_ref, + found_trait_ref: expected_trait_ref, + terr, + })) + }) } fn confirm_trait_upcasting_unsize_candidate( @@ -903,16 +914,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { .map_err(|_| Unimplemented)?; nested.extend(obligations); - // Register one obligation for 'a: 'b. - let cause = ObligationCause::new( - obligation.cause.span, - obligation.cause.body_id, - ObjectCastObligation(source, target), - ); let outlives = ty::OutlivesPredicate(r_a, r_b); nested.push(Obligation::with_depth( tcx, - cause, + obligation.cause.clone(), obligation.recursion_depth + 1, obligation.param_env, obligation.predicate.rebind(outlives), @@ -1003,15 +1008,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { nested.extend(obligations); // Register one obligation for 'a: 'b. - let cause = ObligationCause::new( - obligation.cause.span, - obligation.cause.body_id, - ObjectCastObligation(source, target), - ); let outlives = ty::OutlivesPredicate(r_a, r_b); nested.push(Obligation::with_depth( tcx, - cause, + obligation.cause.clone(), obligation.recursion_depth + 1, obligation.param_env, obligation.predicate.rebind(outlives), @@ -1025,16 +1025,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { return Err(TraitNotObjectSafe(did)); } - let cause = ObligationCause::new( - obligation.cause.span, - obligation.cause.body_id, - ObjectCastObligation(source, target), - ); - let predicate_to_obligation = |predicate| { Obligation::with_depth( tcx, - cause.clone(), + obligation.cause.clone(), obligation.recursion_depth + 1, obligation.param_env, predicate, @@ -1054,8 +1048,12 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { ); // We can only make objects from sized types. - let tr = - ty::Binder::dummy(tcx.at(cause.span).mk_trait_ref(LangItem::Sized, [source])); + let tr = ty::TraitRef::from_lang_item( + tcx, + LangItem::Sized, + obligation.cause.span, + [source], + ); nested.push(predicate_to_obligation(tr.without_const().to_predicate(tcx))); // If the type is `Foo + 'a`, ensure that the type @@ -1125,7 +1123,11 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { // Construct the nested `TailField<T>: Unsize<TailField<U>>` predicate. let tail_unsize_obligation = obligation.with( tcx, - tcx.mk_trait_ref(obligation.predicate.def_id(), [source_tail, target_tail]), + ty::TraitRef::new( + tcx, + obligation.predicate.def_id(), + [source_tail, target_tail], + ), ); nested.push(tail_unsize_obligation); } @@ -1150,8 +1152,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { nested.extend(obligations); // Add a nested `T: Unsize<U>` predicate. - let last_unsize_obligation = obligation - .with(tcx, tcx.mk_trait_ref(obligation.predicate.def_id(), [a_last, b_last])); + let last_unsize_obligation = obligation.with( + tcx, + ty::TraitRef::new(tcx, obligation.predicate.def_id(), [a_last, b_last]), + ); nested.push(last_unsize_obligation); } @@ -1268,17 +1272,19 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { // If we have a projection type, make sure to normalize it so we replace it // with a fresh infer variable - ty::Alias(ty::Projection, ..) => { + ty::Alias(ty::Projection | ty::Inherent, ..) => { let predicate = normalize_with_depth_to( self, obligation.param_env, cause.clone(), obligation.recursion_depth + 1, self_ty.rebind(ty::TraitPredicate { - trait_ref: self - .tcx() - .at(cause.span) - .mk_trait_ref(LangItem::Destruct, [nested_ty]), + trait_ref: ty::TraitRef::from_lang_item( + self.tcx(), + LangItem::Destruct, + cause.span, + [nested_ty], + ), constness: ty::BoundConstness::ConstIfConst, polarity: ty::ImplPolarity::Positive, }), @@ -1299,10 +1305,12 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { // or it's an ADT (and we need to check for a custom impl during selection) _ => { let predicate = self_ty.rebind(ty::TraitPredicate { - trait_ref: self - .tcx() - .at(cause.span) - .mk_trait_ref(LangItem::Destruct, [nested_ty]), + trait_ref: ty::TraitRef::from_lang_item( + self.tcx(), + LangItem::Destruct, + cause.span, + [nested_ty], + ), constness: ty::BoundConstness::ConstIfConst, polarity: ty::ImplPolarity::Positive, }); diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs index 6bb53418b..3baf1c97c 100644 --- a/compiler/rustc_trait_selection/src/traits/select/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs @@ -67,7 +67,7 @@ impl IntercrateAmbiguityCause { /// Emits notes when the overlap is caused by complex intercrate ambiguities. /// See #23980 for details. pub fn add_intercrate_ambiguity_hint(&self, err: &mut Diagnostic) { - err.note(&self.intercrate_ambiguity_hint()); + err.note(self.intercrate_ambiguity_hint()); } pub fn intercrate_ambiguity_hint(&self) -> String { @@ -449,7 +449,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { debug!(?stack, ?candidates, "winnowed to {} candidates", candidates.len()); - let needs_infer = stack.obligation.predicate.has_non_region_infer(); + let has_non_region_infer = stack.obligation.predicate.has_non_region_infer(); // If there are STILL multiple candidates, we can further // reduce the list by dropping duplicates -- including @@ -461,7 +461,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { self.candidate_should_be_dropped_in_favor_of( &candidates[i], &candidates[j], - needs_infer, + has_non_region_infer, ) == DropVictim::Yes }); if should_drop_i { @@ -537,14 +537,22 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { obligation: &PredicateObligation<'tcx>, ) -> Result<EvaluationResult, OverflowError> { self.evaluation_probe(|this| { - if this.tcx().trait_solver_next() { - this.evaluate_predicates_recursively_in_new_solver([obligation.clone()]) + let goal = + this.infcx.resolve_vars_if_possible((obligation.predicate, obligation.param_env)); + let mut result = if this.tcx().trait_solver_next() { + this.evaluate_predicates_recursively_in_new_solver([obligation.clone()])? } else { this.evaluate_predicate_recursively( TraitObligationStackList::empty(&ProvisionalEvaluationCache::default()), obligation.clone(), - ) + )? + }; + // If the predicate has done any inference, then downgrade the + // result to ambiguous. + if this.infcx.shallow_resolve(goal) != goal { + result = result.max(EvaluatedToAmbig); } + Ok(result) }) } @@ -888,7 +896,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { let c1 = tcx.expand_abstract_consts(c1); let c2 = tcx.expand_abstract_consts(c2); debug!( - "evalaute_predicate_recursively: equating consts:\nc1= {:?}\nc2= {:?}", + "evaluate_predicate_recursively: equating consts:\nc1= {:?}\nc2= {:?}", c1, c2 ); @@ -896,8 +904,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { use ty::ConstKind::Unevaluated; match (c1.kind(), c2.kind()) { (Unevaluated(a), Unevaluated(b)) - if a.def.did == b.def.did - && tcx.def_kind(a.def.did) == DefKind::AssocConst => + if a.def == b.def && tcx.def_kind(a.def) == DefKind::AssocConst => { if let Ok(InferOk { obligations, value: () }) = self .infcx @@ -1001,7 +1008,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { ) -> Result<EvaluationResult, OverflowError> { if !self.is_intercrate() && obligation.is_global() - && obligation.param_env.caller_bounds().iter().all(|bound| bound.needs_subst()) + && obligation.param_env.caller_bounds().iter().all(|bound| bound.has_param()) { // If a param env has no global bounds, global obligations do not // depend on its particular value in order to work, so we can clear @@ -1331,7 +1338,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { } if self.can_use_global_caches(param_env) { - if !trait_pred.needs_infer() { + if !trait_pred.has_infer() { debug!(?trait_pred, ?result, "insert_evaluation_cache global"); // This may overwrite the cache with the same value // FIXME: Due to #50507 this overwrites the different values @@ -1517,7 +1524,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { // If there are any inference variables in the `ParamEnv`, then we // always use a cache local to this particular scope. Otherwise, we // switch to a global cache. - if param_env.needs_infer() { + if param_env.has_infer() { return false; } @@ -1588,7 +1595,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { return false; } match result { - Ok(Some(SelectionCandidate::ParamCandidate(trait_ref))) => !trait_ref.needs_infer(), + Ok(Some(SelectionCandidate::ParamCandidate(trait_ref))) => !trait_ref.has_infer(), _ => true, } } @@ -1614,8 +1621,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { if self.can_use_global_caches(param_env) { if let Err(Overflow(OverflowError::Canonical)) = candidate { // Don't cache overflow globally; we only produce this in certain modes. - } else if !pred.needs_infer() { - if !candidate.needs_infer() { + } else if !pred.has_infer() { + if !candidate.has_infer() { debug!(?pred, ?candidate, "insert_candidate_cache global"); // This may overwrite the cache with the same value. tcx.selection_cache.insert((param_env, pred), dep_node, candidate); @@ -1646,7 +1653,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { let tcx = self.infcx.tcx; let (def_id, substs) = match *placeholder_trait_predicate.trait_ref.self_ty().kind() { - ty::Alias(_, ty::AliasTy { def_id, substs, .. }) => (def_id, substs), + ty::Alias(ty::Projection | ty::Opaque, ty::AliasTy { def_id, substs, .. }) => { + (def_id, substs) + } _ => { span_bug!( obligation.cause.span, @@ -1725,7 +1734,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { .map(|InferOk { obligations: _, value: () }| { // This method is called within a probe, so we can't have // inference variables and placeholders escape. - if !trait_bound.needs_infer() && !trait_bound.has_placeholders() { + if !trait_bound.has_infer() && !trait_bound.has_placeholders() { Some(trait_bound) } else { None @@ -1784,12 +1793,12 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { .infcx .at(&obligation.cause, obligation.param_env) .sup(DefineOpaqueTypes::No, obligation.predicate, infer_projection) - .map_or(false, |InferOk { obligations, value: () }| { + .is_ok_and(|InferOk { obligations, value: () }| { self.evaluate_predicates_recursively( TraitObligationStackList::empty(&ProvisionalEvaluationCache::default()), nested_obligations.into_iter().chain(obligations), ) - .map_or(false, |res| res.may_apply()) + .is_ok_and(|res| res.may_apply()) }); if is_match { @@ -1841,7 +1850,7 @@ impl<'tcx> SelectionContext<'_, 'tcx> { &mut self, victim: &EvaluatedCandidate<'tcx>, other: &EvaluatedCandidate<'tcx>, - needs_infer: bool, + has_non_region_infer: bool, ) -> DropVictim { if victim.candidate == other.candidate { return DropVictim::Yes; @@ -1957,7 +1966,7 @@ impl<'tcx> SelectionContext<'_, 'tcx> { | (ObjectCandidate(i), ObjectCandidate(j)) => { // Arbitrarily pick the lower numbered candidate for backwards // compatibility reasons. Don't let this affect inference. - DropVictim::drop_if(i < j && !needs_infer) + DropVictim::drop_if(i < j && !has_non_region_infer) } (ObjectCandidate(_), ProjectionCandidate(..)) | (ProjectionCandidate(..), ObjectCandidate(_)) => { @@ -2063,7 +2072,8 @@ impl<'tcx> SelectionContext<'_, 'tcx> { // existence of multiple marker trait impls tells us nothing // about which one should actually apply. DropVictim::drop_if( - !needs_infer && other.evaluation.must_apply_considering_regions(), + !has_non_region_infer + && other.evaluation.must_apply_considering_regions(), ) } None => DropVictim::No, @@ -2315,7 +2325,7 @@ impl<'tcx> SelectionContext<'_, 'tcx> { | ty::Dynamic(..) | ty::Param(..) | ty::Foreign(..) - | ty::Alias(ty::Projection, ..) + | ty::Alias(ty::Projection | ty::Inherent, ..) | ty::Bound(..) | ty::Infer(ty::TyVar(_) | ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_)) => { bug!("asked to assemble constituent types of unexpected type: {:?}", t); @@ -2413,7 +2423,7 @@ impl<'tcx> SelectionContext<'_, 'tcx> { self.tcx(), cause.clone(), param_env, - self.tcx().mk_trait_ref(trait_def_id, [normalized_ty]), + ty::TraitRef::new(self.tcx(), trait_def_id, [normalized_ty]), ); obligations.push(obligation); obligations @@ -2449,7 +2459,7 @@ impl<'tcx> SelectionContext<'_, 'tcx> { // for a variable being generalized... let guar = self.infcx.tcx.sess.delay_span_bug( obligation.cause.span, - &format!( + format!( "Impl {:?} was matchable against {:?} but now is not", impl_def_id, obligation ), @@ -2647,14 +2657,19 @@ impl<'tcx> SelectionContext<'_, 'tcx> { let predicates = predicates.instantiate_own(tcx, substs); let mut obligations = Vec::with_capacity(predicates.len()); for (index, (predicate, span)) in predicates.into_iter().enumerate() { - let cause = cause.clone().derived_cause(parent_trait_pred, |derived| { - ImplDerivedObligation(Box::new(ImplDerivedObligationCause { - derived, - impl_or_alias_def_id: def_id, - impl_def_predicate_index: Some(index), - span, - })) - }); + let cause = + if Some(parent_trait_pred.def_id()) == tcx.lang_items().coerce_unsized_trait() { + cause.clone() + } else { + cause.clone().derived_cause(parent_trait_pred, |derived| { + ImplDerivedObligation(Box::new(ImplDerivedObligationCause { + derived, + impl_or_alias_def_id: def_id, + impl_def_predicate_index: Some(index), + span, + })) + }) + }; let predicate = normalize_with_depth_to( self, param_env, @@ -3007,16 +3022,16 @@ fn bind_generator_hidden_types_above<'tcx>( // Only remap erased regions if we use them. if considering_regions { - ty = tcx.fold_regions(ty, |mut r, current_depth| { - if let ty::ReErased = r.kind() { + ty = tcx.fold_regions(ty, |r, current_depth| match r.kind() { + ty::ReErased => { let br = ty::BoundRegion { var: ty::BoundVar::from_u32(counter), kind: ty::BrAnon(None), }; counter += 1; - r = tcx.mk_re_late_bound(current_depth, br); + tcx.mk_re_late_bound(current_depth, br) } - r + r => bug!("unexpected region: {r:?}"), }) } diff --git a/compiler/rustc_trait_selection/src/traits/specialize/mod.rs b/compiler/rustc_trait_selection/src/traits/specialize/mod.rs index 8546bbe52..9a4b72013 100644 --- a/compiler/rustc_trait_selection/src/traits/specialize/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/specialize/mod.rs @@ -83,6 +83,30 @@ pub fn translate_substs<'tcx>( source_substs: SubstsRef<'tcx>, target_node: specialization_graph::Node, ) -> SubstsRef<'tcx> { + translate_substs_with_cause( + infcx, + param_env, + source_impl, + source_substs, + target_node, + |_, _| ObligationCause::dummy(), + ) +} + +/// Like [translate_substs], but obligations from the parent implementation +/// are registered with the provided `ObligationCause`. +/// +/// This is for reporting *region* errors from those bounds. Type errors should +/// not happen because the specialization graph already checks for those, and +/// will result in an ICE. +pub fn translate_substs_with_cause<'tcx>( + infcx: &InferCtxt<'tcx>, + param_env: ty::ParamEnv<'tcx>, + source_impl: DefId, + source_substs: SubstsRef<'tcx>, + target_node: specialization_graph::Node, + cause: impl Fn(usize, Span) -> ObligationCause<'tcx>, +) -> SubstsRef<'tcx> { debug!( "translate_substs({:?}, {:?}, {:?}, {:?})", param_env, source_impl, source_substs, target_node @@ -99,14 +123,13 @@ pub fn translate_substs<'tcx>( return source_substs; } - fulfill_implication(infcx, param_env, source_trait_ref, target_impl).unwrap_or_else( - |()| { + fulfill_implication(infcx, param_env, source_trait_ref, source_impl, target_impl, cause) + .unwrap_or_else(|()| { bug!( "When translating substitutions from {source_impl:?} to {target_impl:?}, \ the expected specialization failed to hold" ) - }, - ) + }) } specialization_graph::Node::Trait(..) => source_trait_ref.substs, }; @@ -153,20 +176,12 @@ pub(super) fn specializes(tcx: TyCtxt<'_>, (impl1_def_id, impl2_def_id): (DefId, // Create an infcx, taking the predicates of impl1 as assumptions: let infcx = tcx.infer_ctxt().build(); - let impl1_trait_ref = - match traits::fully_normalize(&infcx, ObligationCause::dummy(), penv, impl1_trait_ref) { - Ok(impl1_trait_ref) => impl1_trait_ref, - Err(_errors) => { - tcx.sess.delay_span_bug( - tcx.def_span(impl1_def_id), - format!("failed to fully normalize {impl1_trait_ref}"), - ); - impl1_trait_ref - } - }; // Attempt to prove that impl2 applies, given all of the above. - fulfill_implication(&infcx, penv, impl1_trait_ref, impl2_def_id).is_ok() + fulfill_implication(&infcx, penv, impl1_trait_ref, impl1_def_id, impl2_def_id, |_, _| { + ObligationCause::dummy() + }) + .is_ok() } /// Attempt to fulfill all obligations of `target_impl` after unification with @@ -178,23 +193,41 @@ fn fulfill_implication<'tcx>( infcx: &InferCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>, source_trait_ref: ty::TraitRef<'tcx>, + source_impl: DefId, target_impl: DefId, + error_cause: impl Fn(usize, Span) -> ObligationCause<'tcx>, ) -> Result<SubstsRef<'tcx>, ()> { debug!( "fulfill_implication({:?}, trait_ref={:?} |- {:?} applies)", param_env, source_trait_ref, target_impl ); + let source_trait_ref = match traits::fully_normalize( + &infcx, + ObligationCause::dummy(), + param_env, + source_trait_ref, + ) { + Ok(source_trait_ref) => source_trait_ref, + Err(_errors) => { + infcx.tcx.sess.delay_span_bug( + infcx.tcx.def_span(source_impl), + format!("failed to fully normalize {source_trait_ref}"), + ); + source_trait_ref + } + }; + let source_trait = ImplSubject::Trait(source_trait_ref); let selcx = &mut SelectionContext::new(&infcx); let target_substs = infcx.fresh_substs_for_item(DUMMY_SP, target_impl); let (target_trait, obligations) = - util::impl_subject_and_oblig(selcx, param_env, target_impl, target_substs); + util::impl_subject_and_oblig(selcx, param_env, target_impl, target_substs, error_cause); // do the impls unify? If not, no specialization. let Ok(InferOk { obligations: more_obligations, .. }) = - infcx.at(&ObligationCause::dummy(), param_env, ).eq(DefineOpaqueTypes::No,source_trait, target_trait) + infcx.at(&ObligationCause::dummy(), param_env).eq(DefineOpaqueTypes::No, source_trait, target_trait) else { debug!( "fulfill_implication: {:?} does not unify with {:?}", @@ -373,7 +406,7 @@ fn report_conflicting_impls<'tcx>( } None => format!("conflicting implementation in crate `{}`", cname), }; - err.note(&msg); + err.note(msg); } } diff --git a/compiler/rustc_trait_selection/src/traits/structural_normalize.rs b/compiler/rustc_trait_selection/src/traits/structural_normalize.rs new file mode 100644 index 000000000..af8dd0da5 --- /dev/null +++ b/compiler/rustc_trait_selection/src/traits/structural_normalize.rs @@ -0,0 +1,55 @@ +use rustc_infer::infer::at::At; +use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind}; +use rustc_infer::traits::{FulfillmentError, TraitEngine}; +use rustc_middle::ty::{self, Ty}; + +use crate::traits::{query::evaluate_obligation::InferCtxtExt, NormalizeExt, Obligation}; + +pub trait StructurallyNormalizeExt<'tcx> { + fn structurally_normalize( + &self, + ty: Ty<'tcx>, + fulfill_cx: &mut dyn TraitEngine<'tcx>, + ) -> Result<Ty<'tcx>, Vec<FulfillmentError<'tcx>>>; +} + +impl<'tcx> StructurallyNormalizeExt<'tcx> for At<'_, 'tcx> { + fn structurally_normalize( + &self, + mut ty: Ty<'tcx>, + fulfill_cx: &mut dyn TraitEngine<'tcx>, + ) -> Result<Ty<'tcx>, Vec<FulfillmentError<'tcx>>> { + assert!(!ty.is_ty_var(), "should have resolved vars before calling"); + + if self.infcx.tcx.trait_solver_next() { + while let ty::Alias(ty::Projection, projection_ty) = *ty.kind() { + let new_infer_ty = self.infcx.next_ty_var(TypeVariableOrigin { + kind: TypeVariableOriginKind::NormalizeProjectionType, + span: self.cause.span, + }); + let obligation = Obligation::new( + self.infcx.tcx, + self.cause.clone(), + self.param_env, + ty::Binder::dummy(ty::ProjectionPredicate { + projection_ty, + term: new_infer_ty.into(), + }), + ); + if self.infcx.predicate_may_hold(&obligation) { + fulfill_cx.register_predicate_obligation(self.infcx, obligation); + let errors = fulfill_cx.select_where_possible(self.infcx); + if !errors.is_empty() { + return Err(errors); + } + ty = self.infcx.resolve_vars_if_possible(new_infer_ty); + } else { + break; + } + } + Ok(ty) + } else { + Ok(self.normalize(ty).into_value_registering_obligations(self.infcx, fulfill_cx)) + } + } +} diff --git a/compiler/rustc_trait_selection/src/traits/util.rs b/compiler/rustc_trait_selection/src/traits/util.rs index 20357d4d2..82f3df401 100644 --- a/compiler/rustc_trait_selection/src/traits/util.rs +++ b/compiler/rustc_trait_selection/src/traits/util.rs @@ -197,6 +197,7 @@ pub fn impl_subject_and_oblig<'a, 'tcx>( param_env: ty::ParamEnv<'tcx>, impl_def_id: DefId, impl_substs: SubstsRef<'tcx>, + cause: impl Fn(usize, Span) -> ObligationCause<'tcx>, ) -> (ImplSubject<'tcx>, impl Iterator<Item = PredicateObligation<'tcx>>) { let subject = selcx.tcx().impl_subject(impl_def_id); let subject = subject.subst(selcx.tcx(), impl_substs); @@ -208,8 +209,7 @@ pub fn impl_subject_and_oblig<'a, 'tcx>( let predicates = predicates.instantiate(selcx.tcx(), impl_substs); let InferOk { value: predicates, obligations: normalization_obligations2 } = selcx.infcx.at(&ObligationCause::dummy(), param_env).normalize(predicates); - let impl_obligations = - super::predicates_for_generics(|_, _| ObligationCause::dummy(), param_env, predicates); + let impl_obligations = super::predicates_for_generics(cause, param_env, predicates); let impl_obligations = impl_obligations .chain(normalization_obligations1.into_iter()) @@ -243,16 +243,11 @@ pub fn get_vtable_index_of_object_method<'tcx, N>( ) -> Option<usize> { // Count number of methods preceding the one we are selecting and // add them to the total offset. - if let Some(index) = tcx - .own_existential_vtable_entries(object.upcast_trait_ref.def_id()) + tcx.own_existential_vtable_entries(object.upcast_trait_ref.def_id()) .iter() .copied() .position(|def_id| def_id == method_def_id) - { - Some(object.vtable_base + index) - } else { - None - } + .map(|index| object.vtable_base + index) } pub fn closure_trait_ref_and_return_type<'tcx>( @@ -267,7 +262,7 @@ pub fn closure_trait_ref_and_return_type<'tcx>( TupleArgumentsFlag::No => sig.skip_binder().inputs()[0], TupleArgumentsFlag::Yes => tcx.mk_tup(sig.skip_binder().inputs()), }; - let trait_ref = tcx.mk_trait_ref(fn_trait_def_id, [self_ty, arguments_tuple]); + let trait_ref = ty::TraitRef::new(tcx, fn_trait_def_id, [self_ty, arguments_tuple]); sig.map_bound(|sig| (trait_ref, sig.output())) } @@ -278,7 +273,7 @@ pub fn generator_trait_ref_and_outputs<'tcx>( sig: ty::PolyGenSig<'tcx>, ) -> ty::Binder<'tcx, (ty::TraitRef<'tcx>, Ty<'tcx>, Ty<'tcx>)> { assert!(!self_ty.has_escaping_bound_vars()); - let trait_ref = tcx.mk_trait_ref(fn_trait_def_id, [self_ty, sig.skip_binder().resume_ty]); + let trait_ref = ty::TraitRef::new(tcx, fn_trait_def_id, [self_ty, sig.skip_binder().resume_ty]); sig.map_bound(|sig| (trait_ref, sig.yield_ty, sig.return_ty)) } @@ -289,7 +284,7 @@ pub fn future_trait_ref_and_outputs<'tcx>( sig: ty::PolyGenSig<'tcx>, ) -> ty::Binder<'tcx, (ty::TraitRef<'tcx>, Ty<'tcx>)> { assert!(!self_ty.has_escaping_bound_vars()); - let trait_ref = tcx.mk_trait_ref(fn_trait_def_id, [self_ty]); + let trait_ref = ty::TraitRef::new(tcx, fn_trait_def_id, [self_ty]); sig.map_bound(|sig| (trait_ref, sig.return_ty)) } diff --git a/compiler/rustc_trait_selection/src/traits/vtable.rs b/compiler/rustc_trait_selection/src/traits/vtable.rs index a4e9928f8..cc674ceee 100644 --- a/compiler/rustc_trait_selection/src/traits/vtable.rs +++ b/compiler/rustc_trait_selection/src/traits/vtable.rs @@ -4,6 +4,7 @@ use rustc_hir::def_id::DefId; use rustc_hir::lang_items::LangItem; use rustc_infer::traits::util::PredicateSet; use rustc_infer::traits::ImplSource; +use rustc_middle::query::Providers; use rustc_middle::ty::visit::TypeVisitableExt; use rustc_middle::ty::InternalSubsts; use rustc_middle::ty::{self, GenericParamDefKind, ToPredicate, Ty, TyCtxt, VtblEntry}; @@ -353,13 +354,13 @@ pub(crate) fn vtable_trait_upcasting_coercion_new_vptr_slot<'tcx>( ), ) -> Option<usize> { let (source, target) = key; - assert!(matches!(&source.kind(), &ty::Dynamic(..)) && !source.needs_infer()); - assert!(matches!(&target.kind(), &ty::Dynamic(..)) && !target.needs_infer()); + assert!(matches!(&source.kind(), &ty::Dynamic(..)) && !source.has_infer()); + assert!(matches!(&target.kind(), &ty::Dynamic(..)) && !target.has_infer()); // this has been typecked-before, so diagnostics is not really needed. let unsize_trait_did = tcx.require_lang_item(LangItem::Unsize, None); - let trait_ref = tcx.mk_trait_ref(unsize_trait_did, [source, target]); + let trait_ref = ty::TraitRef::new(tcx, unsize_trait_did, [source, target]); match tcx.codegen_select_candidate((ty::ParamEnv::reveal_all(), ty::Binder::dummy(trait_ref))) { Ok(ImplSource::TraitUpcasting(implsrc_traitcasting)) => { @@ -379,8 +380,8 @@ pub(crate) fn count_own_vtable_entries<'tcx>( tcx.own_existential_vtable_entries(trait_ref.def_id()).len() } -pub(super) fn provide(providers: &mut ty::query::Providers) { - *providers = ty::query::Providers { +pub(super) fn provide(providers: &mut Providers) { + *providers = Providers { own_existential_vtable_entries, vtable_entries, vtable_trait_upcasting_coercion_new_vptr_slot, diff --git a/compiler/rustc_trait_selection/src/traits/wf.rs b/compiler/rustc_trait_selection/src/traits/wf.rs index 3d026506a..086ab32b5 100644 --- a/compiler/rustc_trait_selection/src/traits/wf.rs +++ b/compiler/rustc_trait_selection/src/traits/wf.rs @@ -58,15 +58,8 @@ pub fn obligations<'tcx>( GenericArgKind::Lifetime(..) => return Some(Vec::new()), }; - let mut wf = WfPredicates { - tcx: infcx.tcx, - param_env, - body_id, - span, - out: vec![], - recursion_depth, - item: None, - }; + let mut wf = + WfPredicates { infcx, param_env, body_id, span, out: vec![], recursion_depth, item: None }; wf.compute(arg); debug!("wf::obligations({:?}, body_id={:?}) = {:?}", arg, body_id, wf.out); @@ -91,7 +84,7 @@ pub fn unnormalized_obligations<'tcx>( debug_assert_eq!(arg, infcx.resolve_vars_if_possible(arg)); let mut wf = WfPredicates { - tcx: infcx.tcx, + infcx, param_env, body_id: CRATE_DEF_ID, span: DUMMY_SP, @@ -116,7 +109,7 @@ pub fn trait_obligations<'tcx>( item: &'tcx hir::Item<'tcx>, ) -> Vec<traits::PredicateObligation<'tcx>> { let mut wf = WfPredicates { - tcx: infcx.tcx, + infcx, param_env, body_id, span, @@ -138,7 +131,7 @@ pub fn predicate_obligations<'tcx>( span: Span, ) -> Vec<traits::PredicateObligation<'tcx>> { let mut wf = WfPredicates { - tcx: infcx.tcx, + infcx, param_env, body_id, span, @@ -170,37 +163,28 @@ pub fn predicate_obligations<'tcx>( ty::PredicateKind::WellFormed(arg) => { wf.compute(arg); } - ty::PredicateKind::ObjectSafe(_) => {} - ty::PredicateKind::ClosureKind(..) => {} - ty::PredicateKind::Subtype(ty::SubtypePredicate { a, b, a_is_expected: _ }) => { - wf.compute(a.into()); - wf.compute(b.into()); - } - ty::PredicateKind::Coerce(ty::CoercePredicate { a, b }) => { - wf.compute(a.into()); - wf.compute(b.into()); - } + ty::PredicateKind::ConstEvaluatable(ct) => { wf.compute(ct.into()); } - ty::PredicateKind::ConstEquate(c1, c2) => { - wf.compute(c1.into()); - wf.compute(c2.into()); - } - ty::PredicateKind::Ambiguous => {} - ty::PredicateKind::TypeWellFormedFromEnv(..) => { - bug!("TypeWellFormedFromEnv is only used for Chalk") - } - ty::PredicateKind::AliasRelate(..) => { - bug!("We should only wf check where clauses and `AliasRelate` is not a `Clause`") + + ty::PredicateKind::ObjectSafe(_) + | ty::PredicateKind::ClosureKind(..) + | ty::PredicateKind::Subtype(..) + | ty::PredicateKind::Coerce(..) + | ty::PredicateKind::ConstEquate(..) + | ty::PredicateKind::Ambiguous + | ty::PredicateKind::AliasRelate(..) + | ty::PredicateKind::TypeWellFormedFromEnv(..) => { + bug!("We should only wf check where clauses, unexpected predicate: {predicate:?}") } } wf.normalize(infcx) } -struct WfPredicates<'tcx> { - tcx: TyCtxt<'tcx>, +struct WfPredicates<'a, 'tcx> { + infcx: &'a InferCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>, body_id: LocalDefId, span: Span, @@ -299,9 +283,9 @@ fn extend_cause_with_original_assoc_item_obligation<'tcx>( } } -impl<'tcx> WfPredicates<'tcx> { +impl<'a, 'tcx> WfPredicates<'a, 'tcx> { fn tcx(&self) -> TyCtxt<'tcx> { - self.tcx + self.infcx.tcx } fn cause(&self, code: traits::ObligationCauseCode<'tcx>) -> traits::ObligationCause<'tcx> { @@ -334,9 +318,16 @@ impl<'tcx> WfPredicates<'tcx> { /// Pushes the obligations required for `trait_ref` to be WF into `self.out`. fn compute_trait_pred(&mut self, trait_pred: &ty::TraitPredicate<'tcx>, elaborate: Elaborate) { - let tcx = self.tcx; + let tcx = self.tcx(); let trait_ref = &trait_pred.trait_ref; + // Negative trait predicates don't require supertraits to hold, just + // that their substs are WF. + if trait_pred.polarity == ty::ImplPolarity::Negative { + self.compute_negative_trait_pred(trait_ref); + return; + } + // if the trait predicate is not const, the wf obligations should not be const as well. let obligations = if trait_pred.constness == ty::BoundConstness::NotConst { self.nominal_obligations_without_const(trait_ref.def_id, trait_ref.substs) @@ -371,7 +362,6 @@ impl<'tcx> WfPredicates<'tcx> { self.out.extend(obligations); } - let tcx = self.tcx(); self.out.extend( trait_ref .substs @@ -402,6 +392,14 @@ impl<'tcx> WfPredicates<'tcx> { ); } + // Compute the obligations that are required for `trait_ref` to be WF, + // given that it is a *negative* trait predicate. + fn compute_negative_trait_pred(&mut self, trait_ref: &ty::TraitRef<'tcx>) { + for arg in trait_ref.substs { + self.compute(arg); + } + } + /// Pushes the obligations required for `trait_ref::Item` to be WF /// into `self.out`. fn compute_projection(&mut self, data: ty::AliasTy<'tcx>) { @@ -430,13 +428,45 @@ impl<'tcx> WfPredicates<'tcx> { let obligations = self.nominal_obligations_without_const(data.def_id, data.substs); self.out.extend(obligations); + self.compute_projection_substs(data.substs); + } + + fn compute_inherent_projection(&mut self, data: ty::AliasTy<'tcx>) { + // An inherent projection is well-formed if + // + // (a) its predicates hold (*) + // (b) its substs are wf + // + // (*) The predicates of an inherent associated type include the + // predicates of the impl that it's contained in. + + if !data.self_ty().has_escaping_bound_vars() { + // FIXME(inherent_associated_types): Should this happen inside of a snapshot? + // FIXME(inherent_associated_types): This is incompatible with the new solver and lazy norm! + let substs = traits::project::compute_inherent_assoc_ty_substs( + &mut traits::SelectionContext::new(self.infcx), + self.param_env, + data, + self.cause(traits::WellFormed(None)), + self.recursion_depth, + &mut self.out, + ); + // Inherent projection types do not require const predicates. + let obligations = self.nominal_obligations_without_const(data.def_id, substs); + self.out.extend(obligations); + } + + self.compute_projection_substs(data.substs); + } + + fn compute_projection_substs(&mut self, substs: SubstsRef<'tcx>) { let tcx = self.tcx(); let cause = self.cause(traits::WellFormed(None)); let param_env = self.param_env; let depth = self.recursion_depth; self.out.extend( - data.substs + substs .iter() .filter(|arg| { matches!(arg.unpack(), GenericArgKind::Type(..) | GenericArgKind::Const(..)) @@ -457,9 +487,10 @@ impl<'tcx> WfPredicates<'tcx> { fn require_sized(&mut self, subty: Ty<'tcx>, cause: traits::ObligationCauseCode<'tcx>) { if !subty.has_escaping_bound_vars() { let cause = self.cause(cause); - let trait_ref = self.tcx.at(cause.span).mk_trait_ref(LangItem::Sized, [subty]); + let trait_ref = + ty::TraitRef::from_lang_item(self.tcx(), LangItem::Sized, cause.span, [subty]); self.out.push(traits::Obligation::with_depth( - self.tcx, + self.tcx(), cause, self.recursion_depth, self.param_env, @@ -487,7 +518,7 @@ impl<'tcx> WfPredicates<'tcx> { match ct.kind() { ty::ConstKind::Unevaluated(uv) => { if !ct.has_escaping_bound_vars() { - let obligations = self.nominal_obligations(uv.def.did, uv.substs); + let obligations = self.nominal_obligations(uv.def, uv.substs); self.out.extend(obligations); let predicate = @@ -598,6 +629,10 @@ impl<'tcx> WfPredicates<'tcx> { walker.skip_current_subtree(); // Subtree handled by compute_projection. self.compute_projection(data); } + ty::Alias(ty::Inherent, data) => { + walker.skip_current_subtree(); // Subtree handled by compute_inherent_projection. + self.compute_inherent_projection(data); + } ty::Adt(def, substs) => { // WfNominalType @@ -690,7 +725,7 @@ impl<'tcx> WfPredicates<'tcx> { // All of the requirements on type parameters // have already been checked for `impl Trait` in // return position. We do need to check type-alias-impl-trait though. - if self.tcx.is_type_alias_impl_trait(def_id) { + if self.tcx().is_type_alias_impl_trait(def_id) { let obligations = self.nominal_obligations(def_id, substs); self.out.extend(obligations); } @@ -760,15 +795,15 @@ impl<'tcx> WfPredicates<'tcx> { substs: SubstsRef<'tcx>, remap_constness: bool, ) -> Vec<traits::PredicateObligation<'tcx>> { - let predicates = self.tcx.predicates_of(def_id); + let predicates = self.tcx().predicates_of(def_id); let mut origins = vec![def_id; predicates.predicates.len()]; let mut head = predicates; while let Some(parent) = head.parent { - head = self.tcx.predicates_of(parent); + head = self.tcx().predicates_of(parent); origins.extend(iter::repeat(parent).take(head.predicates.len())); } - let predicates = predicates.instantiate(self.tcx, substs); + let predicates = predicates.instantiate(self.tcx(), substs); trace!("{:#?}", predicates); debug_assert_eq!(predicates.predicates.len(), origins.len()); @@ -781,10 +816,10 @@ impl<'tcx> WfPredicates<'tcx> { }; let cause = self.cause(code); if remap_constness { - pred = pred.without_const(self.tcx); + pred = pred.without_const(self.tcx()); } traits::Obligation::with_depth( - self.tcx, + self.tcx(), cause, self.recursion_depth, self.param_env, @@ -849,7 +884,7 @@ impl<'tcx> WfPredicates<'tcx> { // Note: in fact we only permit builtin traits, not `Bar<'d>`, I // am looking forward to the future here. if !data.has_escaping_bound_vars() && !region.has_escaping_bound_vars() { - let implicit_bounds = object_region_bounds(self.tcx, data); + let implicit_bounds = object_region_bounds(self.tcx(), data); let explicit_bound = region; @@ -859,7 +894,7 @@ impl<'tcx> WfPredicates<'tcx> { let outlives = ty::Binder::dummy(ty::OutlivesPredicate(explicit_bound, implicit_bound)); self.out.push(traits::Obligation::with_depth( - self.tcx, + self.tcx(), cause, self.recursion_depth, self.param_env, |