diff --git a/compiler/rustc_middle/src/traits/solve.rs b/compiler/rustc_middle/src/traits/solve.rs index 13504c6ae930a..2c3f033925abc 100644 --- a/compiler/rustc_middle/src/traits/solve.rs +++ b/compiler/rustc_middle/src/traits/solve.rs @@ -332,4 +332,9 @@ pub enum CandidateSource { /// } /// ``` AliasBound, + /// A candidate that is registered only during coherence to represent some + /// yet-unknown impl that could be produced downstream without violating orphan + /// rules. + // FIXME: Merge this with the forced ambiguity candidates, so those don't use `Misc`. + CoherenceUnknowable, } diff --git a/compiler/rustc_middle/src/traits/solve/inspect.rs b/compiler/rustc_middle/src/traits/solve/inspect.rs index 1b2e2781bfe72..0f3ace2d55d38 100644 --- a/compiler/rustc_middle/src/traits/solve/inspect.rs +++ b/compiler/rustc_middle/src/traits/solve/inspect.rs @@ -141,10 +141,6 @@ pub enum ProbeKind<'tcx> { TryNormalizeNonRigid { result: QueryResult<'tcx> }, /// Probe entered when normalizing the self ty during candidate assembly NormalizedSelfTyAssembly, - /// Some candidate to prove the current goal. - /// - /// FIXME: Remove this in favor of always using more strongly typed variants. - MiscCandidate { name: &'static str, result: QueryResult<'tcx> }, /// A candidate for proving a trait or alias-relate goal. TraitCandidate { source: CandidateSource, result: QueryResult<'tcx> }, /// Used in the probe that wraps normalizing the non-self type for the unsize @@ -154,4 +150,6 @@ pub enum ProbeKind<'tcx> { /// do a probe to find out what projection type(s) may be used to prove that /// the source type upholds all of the target type's object bounds. UpcastProjectionCompatibility, + /// Try to unify an opaque type with an existing key in the storage. + OpaqueTypeStorageLookup { result: QueryResult<'tcx> }, } diff --git a/compiler/rustc_middle/src/traits/solve/inspect/format.rs b/compiler/rustc_middle/src/traits/solve/inspect/format.rs index 2e2d1df8d1935..2d73be387fdcd 100644 --- a/compiler/rustc_middle/src/traits/solve/inspect/format.rs +++ b/compiler/rustc_middle/src/traits/solve/inspect/format.rs @@ -112,8 +112,8 @@ impl<'a, 'b> ProofTreeFormatter<'a, 'b> { ProbeKind::UpcastProjectionCompatibility => { write!(self.f, "PROBING FOR PROJECTION COMPATIBILITY FOR UPCASTING:") } - ProbeKind::MiscCandidate { name, result } => { - write!(self.f, "CANDIDATE {name}: {result:?}") + ProbeKind::OpaqueTypeStorageLookup { result } => { + write!(self.f, "PROBING FOR AN EXISTING OPAQUE: {result:?}") } ProbeKind::TraitCandidate { source, result } => { write!(self.f, "CANDIDATE {source:?}: {result:?}") diff --git a/compiler/rustc_trait_selection/src/solve/assembly/mod.rs b/compiler/rustc_trait_selection/src/solve/assembly/mod.rs index 9522152909326..b082b0bd4c8a0 100644 --- a/compiler/rustc_trait_selection/src/solve/assembly/mod.rs +++ b/compiler/rustc_trait_selection/src/solve/assembly/mod.rs @@ -48,21 +48,23 @@ pub(super) trait GoalKind<'tcx>: /// [`EvalCtxt::evaluate_added_goals_and_make_canonical_response`]). fn probe_and_match_goal_against_assumption( ecx: &mut EvalCtxt<'_, 'tcx>, + source: CandidateSource, goal: Goal<'tcx, Self>, assumption: ty::Clause<'tcx>, then: impl FnOnce(&mut EvalCtxt<'_, 'tcx>) -> QueryResult<'tcx>, - ) -> QueryResult<'tcx>; + ) -> Result, NoSolution>; /// 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. - fn consider_implied_clause( + fn probe_and_consider_implied_clause( ecx: &mut EvalCtxt<'_, 'tcx>, + source: CandidateSource, goal: Goal<'tcx, Self>, assumption: ty::Clause<'tcx>, requirements: impl IntoIterator>>, - ) -> QueryResult<'tcx> { - Self::probe_and_match_goal_against_assumption(ecx, goal, assumption, |ecx| { + ) -> Result, NoSolution> { + Self::probe_and_match_goal_against_assumption(ecx, source, goal, assumption, |ecx| { // FIXME(-Znext-solver=coinductive): check whether this should be // `GoalSource::ImplWhereBound` for any caller. ecx.add_goals(GoalSource::Misc, requirements); @@ -73,15 +75,16 @@ pub(super) trait GoalKind<'tcx>: /// Consider a clause specifically for a `dyn Trait` self type. This requires /// additionally checking all of the supertraits and object bounds to hold, /// since they're not implied by the well-formedness of the object type. - fn consider_object_bound_candidate( + fn probe_and_consider_object_bound_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, + source: CandidateSource, goal: Goal<'tcx, Self>, assumption: ty::Clause<'tcx>, - ) -> QueryResult<'tcx> { - Self::probe_and_match_goal_against_assumption(ecx, goal, assumption, |ecx| { + ) -> Result, NoSolution> { + Self::probe_and_match_goal_against_assumption(ecx, source, 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`"); + bug!("expected object type in `probe_and_consider_object_bound_candidate`"); }; // FIXME(-Znext-solver=coinductive): Should this be `GoalSource::ImplWhereBound`? ecx.add_goals( @@ -112,7 +115,7 @@ pub(super) trait GoalKind<'tcx>: fn consider_error_guaranteed_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, guar: ErrorGuaranteed, - ) -> QueryResult<'tcx>; + ) -> Result, NoSolution>; /// A type implements an `auto trait` if its components do as well. /// @@ -121,13 +124,13 @@ pub(super) trait GoalKind<'tcx>: fn consider_auto_trait_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx>; + ) -> Result, NoSolution>; /// A trait alias holds if the RHS traits and `where` clauses hold. fn consider_trait_alias_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx>; + ) -> Result, NoSolution>; /// A type is `Sized` if its tail component is `Sized`. /// @@ -136,7 +139,7 @@ pub(super) trait GoalKind<'tcx>: fn consider_builtin_sized_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx>; + ) -> Result, NoSolution>; /// A type is `Copy` or `Clone` if its components are `Copy` or `Clone`. /// @@ -145,20 +148,20 @@ pub(super) trait GoalKind<'tcx>: fn consider_builtin_copy_clone_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx>; + ) -> Result, NoSolution>; /// A type is `PointerLike` if we can compute its layout, and that layout /// matches the layout of `usize`. fn consider_builtin_pointer_like_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx>; + ) -> Result, NoSolution>; /// A type is a `FnPtr` if it is of `FnPtr` type. fn consider_builtin_fn_ptr_trait_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx>; + ) -> Result, NoSolution>; /// A callable type (a closure, fn def, or fn ptr) is known to implement the `Fn` /// family of traits where `A` is given by the signature of the type. @@ -166,7 +169,7 @@ pub(super) trait GoalKind<'tcx>: ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, kind: ty::ClosureKind, - ) -> QueryResult<'tcx>; + ) -> Result, NoSolution>; /// An async closure is known to implement the `AsyncFn` family of traits /// where `A` is given by the signature of the type. @@ -174,7 +177,7 @@ pub(super) trait GoalKind<'tcx>: ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, kind: ty::ClosureKind, - ) -> QueryResult<'tcx>; + ) -> Result, NoSolution>; /// Compute the built-in logic of the `AsyncFnKindHelper` helper trait, which /// is used internally to delay computation for async closures until after @@ -182,13 +185,13 @@ pub(super) trait GoalKind<'tcx>: fn consider_builtin_async_fn_kind_helper_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx>; + ) -> Result, NoSolution>; /// `Tuple` is implemented if the `Self` type is a tuple. fn consider_builtin_tuple_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx>; + ) -> Result, NoSolution>; /// `Pointee` is always implemented. /// @@ -198,7 +201,7 @@ pub(super) trait GoalKind<'tcx>: fn consider_builtin_pointee_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx>; + ) -> Result, NoSolution>; /// A coroutine (that comes from an `async` desugaring) is known to implement /// `Future`, where `O` is given by the coroutine's return type @@ -206,7 +209,7 @@ pub(super) trait GoalKind<'tcx>: fn consider_builtin_future_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx>; + ) -> Result, NoSolution>; /// A coroutine (that comes from a `gen` desugaring) is known to implement /// `Iterator`, where `O` is given by the generator's yield type @@ -214,19 +217,19 @@ pub(super) trait GoalKind<'tcx>: fn consider_builtin_iterator_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx>; + ) -> Result, NoSolution>; /// A coroutine (that comes from a `gen` desugaring) is known to implement /// `FusedIterator` fn consider_builtin_fused_iterator_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx>; + ) -> Result, NoSolution>; fn consider_builtin_async_iterator_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx>; + ) -> Result, NoSolution>; /// A coroutine (that doesn't come from an `async` or `gen` desugaring) is known to /// implement `Coroutine`, given the resume, yield, @@ -234,27 +237,27 @@ pub(super) trait GoalKind<'tcx>: fn consider_builtin_coroutine_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx>; + ) -> Result, NoSolution>; fn consider_builtin_discriminant_kind_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx>; + ) -> Result, NoSolution>; fn consider_builtin_async_destruct_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx>; + ) -> Result, NoSolution>; fn consider_builtin_destruct_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx>; + ) -> Result, NoSolution>; fn consider_builtin_transmute_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx>; + ) -> Result, NoSolution>; /// Consider (possibly several) candidates to upcast or unsize a type to another /// type, excluding the coercion of a sized type into a `dyn Trait`. @@ -266,7 +269,7 @@ pub(super) trait GoalKind<'tcx>: fn consider_structural_builtin_unsize_candidates( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> Vec<(CanonicalResponse<'tcx>, BuiltinImplSource)>; + ) -> Vec>; } impl<'tcx> EvalCtxt<'_, 'tcx> { @@ -282,7 +285,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { if normalized_self_ty.is_ty_var() { debug!("self type has been normalized to infer"); - return self.forced_ambiguity(MaybeCause::Ambiguity); + return self.forced_ambiguity(MaybeCause::Ambiguity).into_iter().collect(); } let goal = @@ -315,7 +318,10 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { candidates } - fn forced_ambiguity(&mut self, cause: MaybeCause) -> Vec> { + pub(super) fn forced_ambiguity( + &mut self, + cause: MaybeCause, + ) -> Result, NoSolution> { // This may fail if `try_evaluate_added_goals` overflows because it // fails to reach a fixpoint but ends up getting an error after // running for some additional step. @@ -323,10 +329,8 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { // cc trait-system-refactor-initiative#105 let source = CandidateSource::BuiltinImpl(BuiltinImplSource::Misc); let certainty = Certainty::Maybe(cause); - let result = self - .probe_trait_candidate(source) - .enter(|this| this.evaluate_added_goals_and_make_canonical_response(certainty)); - if let Ok(cand) = result { vec![cand] } else { vec![] } + self.probe_trait_candidate(source) + .enter(|this| this.evaluate_added_goals_and_make_canonical_response(certainty)) } #[instrument(level = "debug", skip_all)] @@ -533,20 +537,12 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { Err(NoSolution) }; - match result { - Ok(result) => candidates.push(Candidate { - source: CandidateSource::BuiltinImpl(BuiltinImplSource::Misc), - result, - }), - Err(NoSolution) => (), - } + candidates.extend(result); // There may be multiple unsize candidates for a trait with several supertraits: // `trait Foo: Bar + Bar` and `dyn Foo: Unsize>` if lang_items.unsize_trait() == Some(trait_def_id) { - for (result, source) in G::consider_structural_builtin_unsize_candidates(self, goal) { - candidates.push(Candidate { source: CandidateSource::BuiltinImpl(source), result }); - } + candidates.extend(G::consider_structural_builtin_unsize_candidates(self, goal)); } } @@ -557,12 +553,13 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { candidates: &mut Vec>, ) { for (i, assumption) in goal.param_env.caller_bounds().iter().enumerate() { - match G::consider_implied_clause(self, goal, assumption, []) { - Ok(result) => { - candidates.push(Candidate { source: CandidateSource::ParamEnv(i), result }) - } - Err(NoSolution) => (), - } + candidates.extend(G::probe_and_consider_implied_clause( + self, + CandidateSource::ParamEnv(i), + goal, + assumption, + [], + )); } } @@ -648,12 +645,13 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { for assumption in self.tcx().item_bounds(alias_ty.def_id).instantiate(self.tcx(), alias_ty.args) { - match G::consider_implied_clause(self, goal, assumption, []) { - Ok(result) => { - candidates.push(Candidate { source: CandidateSource::AliasBound, result }); - } - Err(NoSolution) => {} - } + candidates.extend(G::probe_and_consider_implied_clause( + self, + CandidateSource::AliasBound, + goal, + assumption, + [], + )); } if kind != ty::Projection { @@ -728,17 +726,12 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { } ty::ExistentialPredicate::Projection(_) | ty::ExistentialPredicate::AutoTrait(_) => { - match G::consider_object_bound_candidate( + candidates.extend(G::probe_and_consider_object_bound_candidate( self, + CandidateSource::BuiltinImpl(BuiltinImplSource::Misc), goal, bound.with_self_ty(tcx, self_ty), - ) { - Ok(result) => candidates.push(Candidate { - source: CandidateSource::BuiltinImpl(BuiltinImplSource::Misc), - result, - }), - Err(NoSolution) => (), - } + )); } } } @@ -749,15 +742,12 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { if let Some(principal) = bounds.principal() { let principal_trait_ref = principal.with_self_ty(tcx, self_ty); self.walk_vtable(principal_trait_ref, |ecx, assumption, vtable_base, _| { - match G::consider_object_bound_candidate(ecx, goal, assumption.to_predicate(tcx)) { - Ok(result) => candidates.push(Candidate { - source: CandidateSource::BuiltinImpl(BuiltinImplSource::Object { - vtable_base, - }), - result, - }), - Err(NoSolution) => (), - } + candidates.extend(G::probe_and_consider_object_bound_candidate( + ecx, + CandidateSource::BuiltinImpl(BuiltinImplSource::Object { vtable_base }), + goal, + assumption.to_predicate(tcx), + )); }); } } @@ -775,25 +765,20 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { candidates: &mut Vec>, ) { let tcx = self.tcx(); - let result = self.probe_misc_candidate("coherence unknowable").enter(|ecx| { - let trait_ref = goal.predicate.trait_ref(tcx); - let lazily_normalize_ty = |ty| ecx.structurally_normalize_ty(goal.param_env, ty); - - match coherence::trait_ref_is_knowable(tcx, trait_ref, lazily_normalize_ty)? { - Ok(()) => Err(NoSolution), - Err(_) => { - ecx.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS) - } - } - }); - match result { - Ok(result) => candidates.push(Candidate { - source: CandidateSource::BuiltinImpl(BuiltinImplSource::Misc), - result, - }), - Err(NoSolution) => {} - } + candidates.extend(self.probe_trait_candidate(CandidateSource::CoherenceUnknowable).enter( + |ecx| { + let trait_ref = goal.predicate.trait_ref(tcx); + let lazily_normalize_ty = |ty| ecx.structurally_normalize_ty(goal.param_env, ty); + + match coherence::trait_ref_is_knowable(tcx, trait_ref, lazily_normalize_ty)? { + Ok(()) => Err(NoSolution), + Err(_) => { + ecx.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS) + } + } + }, + )) } /// If there's a where-bound for the current goal, do not use any impl candidates @@ -838,6 +823,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { false } CandidateSource::ParamEnv(_) | CandidateSource::AliasBound => true, + CandidateSource::CoherenceUnknowable => bug!("uh oh"), }); } // If it is still ambiguous we instead just force the whole goal @@ -845,7 +831,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { // tests/ui/traits/next-solver/env-shadows-impls/ambig-env-no-shadow.rs Certainty::Maybe(cause) => { debug!(?cause, "force ambiguity"); - *candidates = self.forced_ambiguity(cause); + *candidates = self.forced_ambiguity(cause).into_iter().collect(); } } } diff --git a/compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs b/compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs index 21efce7487924..d8fd5c0591141 100644 --- a/compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs +++ b/compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs @@ -998,19 +998,24 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { if candidate_key.def_id != key.def_id { continue; } - values.extend(self.probe_misc_candidate("opaque type storage").enter(|ecx| { - for (a, b) in std::iter::zip(candidate_key.args, key.args) { - ecx.eq(param_env, a, b)?; - } - ecx.eq(param_env, candidate_ty, ty)?; - ecx.add_item_bounds_for_hidden_type( - candidate_key.def_id.to_def_id(), - candidate_key.args, - param_env, - candidate_ty, - ); - ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) - })); + values.extend( + self.probe(|result| inspect::ProbeKind::OpaqueTypeStorageLookup { + result: *result, + }) + .enter(|ecx| { + for (a, b) in std::iter::zip(candidate_key.args, key.args) { + ecx.eq(param_env, a, b)?; + } + ecx.eq(param_env, candidate_ty, ty)?; + ecx.add_item_bounds_for_hidden_type( + candidate_key.def_id.to_def_id(), + candidate_key.args, + param_env, + candidate_ty, + ); + ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + }), + ); } values } diff --git a/compiler/rustc_trait_selection/src/solve/eval_ctxt/probe.rs b/compiler/rustc_trait_selection/src/solve/eval_ctxt/probe.rs index 9d59723e44157..ee23f49939b7c 100644 --- a/compiler/rustc_trait_selection/src/solve/eval_ctxt/probe.rs +++ b/compiler/rustc_trait_selection/src/solve/eval_ctxt/probe.rs @@ -1,6 +1,7 @@ use crate::solve::assembly::Candidate; use super::EvalCtxt; +use rustc_infer::traits::BuiltinImplSource; use rustc_middle::traits::{ query::NoSolution, solve::{inspect, CandidateSource, QueryResult}, @@ -75,24 +76,12 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> { ProbeCtxt { ecx: self, probe_kind, _result: PhantomData } } - pub(in crate::solve) fn probe_misc_candidate( + pub(in crate::solve) fn probe_builtin_trait_candidate( &mut self, - name: &'static str, - ) -> ProbeCtxt< - '_, - 'a, - 'tcx, - impl FnOnce(&QueryResult<'tcx>) -> inspect::ProbeKind<'tcx>, - QueryResult<'tcx>, - > { - ProbeCtxt { - ecx: self, - probe_kind: move |result: &QueryResult<'tcx>| inspect::ProbeKind::MiscCandidate { - name, - result: *result, - }, - _result: PhantomData, - } + source: BuiltinImplSource, + ) -> TraitProbeCtxt<'_, 'a, 'tcx, impl FnOnce(&QueryResult<'tcx>) -> inspect::ProbeKind<'tcx>> + { + self.probe_trait_candidate(CandidateSource::BuiltinImpl(source)) } pub(in crate::solve) fn probe_trait_candidate( diff --git a/compiler/rustc_trait_selection/src/solve/eval_ctxt/select.rs b/compiler/rustc_trait_selection/src/solve/eval_ctxt/select.rs index 6644d3c77afd9..6cce37642c11b 100644 --- a/compiler/rustc_trait_selection/src/solve/eval_ctxt/select.rs +++ b/compiler/rustc_trait_selection/src/solve/eval_ctxt/select.rs @@ -107,6 +107,8 @@ impl<'tcx> InferCtxt<'tcx> { Ok(Some(ImplSource::Param(vec![]))) } + (_, CandidateSource::CoherenceUnknowable) => bug!(), + (Certainty::Maybe(_), _) => Ok(None), } }) diff --git a/compiler/rustc_trait_selection/src/solve/inspect/analyse.rs b/compiler/rustc_trait_selection/src/solve/inspect/analyse.rs index e918f20577cc8..2d58111e80385 100644 --- a/compiler/rustc_trait_selection/src/solve/inspect/analyse.rs +++ b/compiler/rustc_trait_selection/src/solve/inspect/analyse.rs @@ -45,7 +45,7 @@ pub struct InspectCandidate<'a, 'tcx> { nested_goals: Vec>>>, final_state: inspect::CanonicalState<'tcx, ()>, result: QueryResult<'tcx>, - candidate_certainty: Option, + shallow_certainty: Certainty, } impl<'a, 'tcx> InspectCandidate<'a, 'tcx> { @@ -59,15 +59,14 @@ impl<'a, 'tcx> InspectCandidate<'a, 'tcx> { /// Certainty passed into `evaluate_added_goals_and_make_canonical_response`. /// - /// If this certainty is `Some(Yes)`, then we must be confident that the candidate + /// If this certainty is `Yes`, then we must be confident that the candidate /// must hold iff it's nested goals hold. This is not true if the certainty is - /// `Some(Maybe)`, which suggests we forced ambiguity instead, or if it is `None`, - /// which suggests we may have not assembled any candidates at all. + /// `Maybe(..)`, which suggests we forced ambiguity instead. /// - /// This is *not* the certainty of the candidate's nested evaluation, which can be - /// accessed with [`Self::result`] instead. - pub fn candidate_certainty(&self) -> Option { - self.candidate_certainty + /// This is *not* the certainty of the candidate's full nested evaluation, which + /// can be accessed with [`Self::result`] instead. + pub fn shallow_certainty(&self) -> Certainty { + self.shallow_certainty } /// Visit all nested goals of this candidate without rolling @@ -174,9 +173,7 @@ impl<'a, 'tcx> InspectGoal<'a, 'tcx> { nested_goals: &mut Vec>>>, probe: &inspect::Probe<'tcx>, ) { - let mut candidate_certainty = None; - let num_candidates = candidates.len(); - + let mut shallow_certainty = None; for step in &probe.steps { match step { &inspect::ProbeStep::AddGoal(_source, goal) => nested_goals.push(goal), @@ -188,8 +185,8 @@ impl<'a, 'tcx> InspectGoal<'a, 'tcx> { self.candidates_recur(candidates, nested_goals, probe); nested_goals.truncate(num_goals); } - inspect::ProbeStep::MakeCanonicalResponse { shallow_certainty } => { - assert_eq!(candidate_certainty.replace(*shallow_certainty), None); + inspect::ProbeStep::MakeCanonicalResponse { shallow_certainty: c } => { + assert_eq!(shallow_certainty.replace(*c), None); } inspect::ProbeStep::EvaluateGoals(_) => (), } @@ -199,36 +196,26 @@ impl<'a, 'tcx> InspectGoal<'a, 'tcx> { inspect::ProbeKind::NormalizedSelfTyAssembly | inspect::ProbeKind::UnsizeAssembly | inspect::ProbeKind::UpcastProjectionCompatibility => (), - // We add a candidate for the root evaluation if there + + // We add a candidate even for the root evaluation if there // is only one way to prove a given goal, e.g. for `WellFormed`. - // - // FIXME: This is currently wrong if we don't even try any - // candidates, e.g. for a trait goal, as in this case `candidates` is - // actually supposed to be empty. inspect::ProbeKind::Root { result } - | inspect::ProbeKind::TryNormalizeNonRigid { result } => { - if candidates.len() == num_candidates { + | inspect::ProbeKind::TryNormalizeNonRigid { result } + | inspect::ProbeKind::TraitCandidate { source: _, result } + | inspect::ProbeKind::OpaqueTypeStorageLookup { result } => { + // We only add a candidate if `shallow_certainty` was set, which means + // that we ended up calling `evaluate_added_goals_and_make_canonical_response`. + if let Some(shallow_certainty) = shallow_certainty { candidates.push(InspectCandidate { goal: self, kind: probe.kind, nested_goals: nested_goals.clone(), final_state: probe.final_state, result, - candidate_certainty, - }) + shallow_certainty, + }); } } - inspect::ProbeKind::MiscCandidate { name: _, result } - | inspect::ProbeKind::TraitCandidate { source: _, result } => { - candidates.push(InspectCandidate { - goal: self, - kind: probe.kind, - nested_goals: nested_goals.clone(), - final_state: probe.final_state, - result, - candidate_certainty, - }); - } } } diff --git a/compiler/rustc_trait_selection/src/solve/normalizes_to/mod.rs b/compiler/rustc_trait_selection/src/solve/normalizes_to/mod.rs index c662ab23c53b6..dab87fffe461e 100644 --- a/compiler/rustc_trait_selection/src/solve/normalizes_to/mod.rs +++ b/compiler/rustc_trait_selection/src/solve/normalizes_to/mod.rs @@ -8,11 +8,10 @@ use rustc_hir::def_id::DefId; use rustc_hir::LangItem; use rustc_infer::traits::query::NoSolution; use rustc_infer::traits::solve::inspect::ProbeKind; +use rustc_infer::traits::solve::MaybeCause; use rustc_infer::traits::specialization_graph::LeafDef; use rustc_infer::traits::Reveal; -use rustc_middle::traits::solve::{ - CandidateSource, CanonicalResponse, Certainty, Goal, QueryResult, -}; +use rustc_middle::traits::solve::{CandidateSource, Certainty, Goal, QueryResult}; use rustc_middle::traits::BuiltinImplSource; use rustc_middle::ty::fast_reject::{DeepRejectCtxt, TreatParams}; use rustc_middle::ty::NormalizesTo; @@ -119,14 +118,15 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> { fn probe_and_match_goal_against_assumption( ecx: &mut EvalCtxt<'_, 'tcx>, + source: CandidateSource, goal: Goal<'tcx, Self>, assumption: ty::Clause<'tcx>, then: impl FnOnce(&mut EvalCtxt<'_, 'tcx>) -> QueryResult<'tcx>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { if let Some(projection_pred) = assumption.as_projection_clause() { if projection_pred.projection_def_id() == goal.predicate.def_id() { let tcx = ecx.tcx(); - ecx.probe_misc_candidate("assumption").enter(|ecx| { + ecx.probe_trait_candidate(source).enter(|ecx| { let assumption_projection_pred = ecx.instantiate_binder_with_infer(projection_pred); ecx.eq( @@ -300,14 +300,14 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> { fn consider_error_guaranteed_candidate( _ecx: &mut EvalCtxt<'_, 'tcx>, _guar: ErrorGuaranteed, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { Err(NoSolution) } fn consider_auto_trait_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { ecx.tcx().dcx().span_delayed_bug( ecx.tcx().def_span(goal.predicate.def_id()), "associated types not allowed on auto traits", @@ -318,35 +318,35 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> { fn consider_trait_alias_candidate( _ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { bug!("trait aliases do not have associated types: {:?}", goal); } fn consider_builtin_sized_candidate( _ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { bug!("`Sized` does not have an associated type: {:?}", goal); } fn consider_builtin_copy_clone_candidate( _ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { bug!("`Copy`/`Clone` does not have an associated type: {:?}", goal); } fn consider_builtin_pointer_like_candidate( _ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { bug!("`PointerLike` does not have an associated type: {:?}", goal); } fn consider_builtin_fn_ptr_trait_candidate( _ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { bug!("`FnPtr` does not have an associated type: {:?}", goal); } @@ -354,7 +354,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, goal_kind: ty::ClosureKind, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { let tcx = ecx.tcx(); let tupled_inputs_and_output = match structural_traits::extract_tupled_inputs_and_output_from_callable( @@ -364,8 +364,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> { )? { Some(tupled_inputs_and_output) => tupled_inputs_and_output, None => { - return ecx - .evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS); + return ecx.forced_ambiguity(MaybeCause::Ambiguity); } }; let output_is_sized_pred = tupled_inputs_and_output.map_bound(|(_, output)| { @@ -385,14 +384,20 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> { // A built-in `Fn` impl only holds if the output is sized. // (FIXME: technically we only need to check this if the type is a fn ptr...) - Self::consider_implied_clause(ecx, goal, pred, [goal.with(tcx, output_is_sized_pred)]) + Self::probe_and_consider_implied_clause( + ecx, + CandidateSource::BuiltinImpl(BuiltinImplSource::Misc), + goal, + pred, + [goal.with(tcx, output_is_sized_pred)], + ) } fn consider_builtin_async_fn_trait_candidates( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, goal_kind: ty::ClosureKind, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { let tcx = ecx.tcx(); let env_region = match goal_kind { @@ -461,8 +466,9 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> { // A built-in `AsyncFn` impl only holds if the output is sized. // (FIXME: technically we only need to check this if the type is a fn ptr...) - Self::consider_implied_clause( + Self::probe_and_consider_implied_clause( ecx, + CandidateSource::BuiltinImpl(BuiltinImplSource::Misc), goal, pred, [goal.with(tcx, output_is_sized_pred)] @@ -474,7 +480,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> { fn consider_builtin_async_fn_kind_helper_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { let [ closure_fn_kind_ty, goal_kind_ty, @@ -489,7 +495,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> { // Bail if the upvars haven't been constrained. if tupled_upvars_ty.expect_ty().is_ty_var() { - return ecx.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS); + return ecx.forced_ambiguity(MaybeCause::Ambiguity); } let Some(closure_kind) = closure_fn_kind_ty.expect_ty().to_opt_closure_kind() else { @@ -512,25 +518,27 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> { borrow_region.expect_region(), ); - ecx.instantiate_normalizes_to_term(goal, upvars_ty.into()); - ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc).enter(|ecx| { + ecx.instantiate_normalizes_to_term(goal, upvars_ty.into()); + ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + }) } fn consider_builtin_tuple_candidate( _ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { bug!("`Tuple` does not have an associated type: {:?}", goal); } fn consider_builtin_pointee_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { let tcx = ecx.tcx(); let metadata_def_id = tcx.require_lang_item(LangItem::Metadata, None); assert_eq!(metadata_def_id, goal.predicate.def_id()); - ecx.probe_misc_candidate("builtin pointee").enter(|ecx| { + ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc).enter(|ecx| { let metadata_ty = match goal.predicate.self_ty().kind() { ty::Bool | ty::Char @@ -609,7 +617,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> { fn consider_builtin_future_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { let self_ty = goal.predicate.self_ty(); let ty::Coroutine(def_id, args) = *self_ty.kind() else { return Err(NoSolution); @@ -623,8 +631,9 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> { let term = args.as_coroutine().return_ty().into(); - Self::consider_implied_clause( + Self::probe_and_consider_implied_clause( ecx, + CandidateSource::BuiltinImpl(BuiltinImplSource::Misc), goal, ty::ProjectionPredicate { projection_ty: ty::AliasTy::new(ecx.tcx(), goal.predicate.def_id(), [self_ty]), @@ -640,7 +649,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> { fn consider_builtin_iterator_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { let self_ty = goal.predicate.self_ty(); let ty::Coroutine(def_id, args) = *self_ty.kind() else { return Err(NoSolution); @@ -654,8 +663,9 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> { let term = args.as_coroutine().yield_ty().into(); - Self::consider_implied_clause( + Self::probe_and_consider_implied_clause( ecx, + CandidateSource::BuiltinImpl(BuiltinImplSource::Misc), goal, ty::ProjectionPredicate { projection_ty: ty::AliasTy::new(ecx.tcx(), goal.predicate.def_id(), [self_ty]), @@ -671,14 +681,14 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> { fn consider_builtin_fused_iterator_candidate( _ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { bug!("`FusedIterator` does not have an associated type: {:?}", goal); } fn consider_builtin_async_iterator_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { let self_ty = goal.predicate.self_ty(); let ty::Coroutine(def_id, args) = *self_ty.kind() else { return Err(NoSolution); @@ -690,7 +700,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> { return Err(NoSolution); } - ecx.probe_misc_candidate("builtin AsyncIterator kind").enter(|ecx| { + ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc).enter(|ecx| { let expected_ty = ecx.next_ty_infer(); // Take `AsyncIterator` and turn it into the corresponding // coroutine yield ty `Poll>`. @@ -714,7 +724,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> { fn consider_builtin_coroutine_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { let self_ty = goal.predicate.self_ty(); let ty::Coroutine(def_id, args) = *self_ty.kind() else { return Err(NoSolution); @@ -737,8 +747,9 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> { bug!("unexpected associated item `<{self_ty} as Coroutine>::{name}`") }; - Self::consider_implied_clause( + Self::probe_and_consider_implied_clause( ecx, + CandidateSource::BuiltinImpl(BuiltinImplSource::Misc), goal, ty::ProjectionPredicate { projection_ty: ty::AliasTy::new( @@ -758,14 +769,14 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> { fn consider_structural_builtin_unsize_candidates( _ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> Vec<(CanonicalResponse<'tcx>, BuiltinImplSource)> { + ) -> Vec> { bug!("`Unsize` does not have an associated type: {:?}", goal); } fn consider_builtin_discriminant_kind_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { let self_ty = goal.predicate.self_ty(); let discriminant_ty = match *self_ty.kind() { ty::Bool @@ -808,7 +819,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> { ), }; - ecx.probe_misc_candidate("builtin discriminant kind").enter(|ecx| { + ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc).enter(|ecx| { ecx.instantiate_normalizes_to_term(goal, discriminant_ty.into()); ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) }) @@ -817,7 +828,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> { fn consider_builtin_async_destruct_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { let self_ty = goal.predicate.self_ty(); let async_destructor_ty = match *self_ty.kind() { ty::Bool @@ -860,7 +871,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> { ), }; - ecx.probe_misc_candidate("builtin async destruct").enter(|ecx| { + ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc).enter(|ecx| { ecx.eq(goal.param_env, goal.predicate.term, async_destructor_ty.into()) .expect("expected goal term to be fully unconstrained"); ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) @@ -870,14 +881,14 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> { fn consider_builtin_destruct_candidate( _ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { bug!("`Destruct` does not have an associated type: {:?}", goal); } fn consider_builtin_transmute_candidate( _ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { bug!("`BikeshedIntrinsicFrom` does not have an associated type: {:?}", goal) } } diff --git a/compiler/rustc_trait_selection/src/solve/trait_goals.rs b/compiler/rustc_trait_selection/src/solve/trait_goals.rs index f6d12a9a0138e..c8cb14abb554d 100644 --- a/compiler/rustc_trait_selection/src/solve/trait_goals.rs +++ b/compiler/rustc_trait_selection/src/solve/trait_goals.rs @@ -9,10 +9,9 @@ use rustc_data_structures::fx::FxIndexSet; use rustc_hir::def_id::DefId; use rustc_hir::{LangItem, Movability}; use rustc_infer::traits::query::NoSolution; +use rustc_infer::traits::solve::MaybeCause; use rustc_middle::traits::solve::inspect::ProbeKind; -use rustc_middle::traits::solve::{ - CandidateSource, CanonicalResponse, Certainty, Goal, QueryResult, -}; +use rustc_middle::traits::solve::{CandidateSource, Certainty, Goal, QueryResult}; use rustc_middle::traits::{BuiltinImplSource, Reveal}; use rustc_middle::ty::fast_reject::{DeepRejectCtxt, TreatParams}; use rustc_middle::ty::{self, ToPredicate, Ty, TyCtxt}; @@ -94,21 +93,24 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { fn consider_error_guaranteed_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, _guar: ErrorGuaranteed, - ) -> QueryResult<'tcx> { - ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + ) -> Result, NoSolution> { + // FIXME: don't need to enter a probe here. + ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc) + .enter(|ecx| ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)) } fn probe_and_match_goal_against_assumption( ecx: &mut EvalCtxt<'_, 'tcx>, + source: CandidateSource, goal: Goal<'tcx, Self>, assumption: ty::Clause<'tcx>, then: impl FnOnce(&mut EvalCtxt<'_, 'tcx>) -> QueryResult<'tcx>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { if let Some(trait_clause) = assumption.as_trait_clause() { if trait_clause.def_id() == goal.predicate.def_id() && trait_clause.polarity() == goal.predicate.polarity { - ecx.probe_misc_candidate("assumption").enter(|ecx| { + ecx.probe_trait_candidate(source).enter(|ecx| { let assumption_trait_pred = ecx.instantiate_binder_with_infer(trait_clause); ecx.eq( goal.param_env, @@ -128,7 +130,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { fn consider_auto_trait_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { if goal.predicate.polarity != ty::PredicatePolarity::Positive { return Err(NoSolution); } @@ -162,6 +164,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { } ecx.probe_and_evaluate_goal_for_constituent_tys( + CandidateSource::BuiltinImpl(BuiltinImplSource::Misc), goal, structural_traits::instantiate_constituent_tys_for_auto_trait, ) @@ -170,14 +173,14 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { fn consider_trait_alias_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { if goal.predicate.polarity != ty::PredicatePolarity::Positive { return Err(NoSolution); } let tcx = ecx.tcx(); - ecx.probe_misc_candidate("trait alias").enter(|ecx| { + ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc).enter(|ecx| { let nested_obligations = tcx .predicates_of(goal.predicate.def_id()) .instantiate(tcx, goal.predicate.trait_ref.args); @@ -193,12 +196,13 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { fn consider_builtin_sized_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { if goal.predicate.polarity != ty::PredicatePolarity::Positive { return Err(NoSolution); } ecx.probe_and_evaluate_goal_for_constituent_tys( + CandidateSource::BuiltinImpl(BuiltinImplSource::Misc), goal, structural_traits::instantiate_constituent_tys_for_sized_trait, ) @@ -207,12 +211,13 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { fn consider_builtin_copy_clone_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { if goal.predicate.polarity != ty::PredicatePolarity::Positive { return Err(NoSolution); } ecx.probe_and_evaluate_goal_for_constituent_tys( + CandidateSource::BuiltinImpl(BuiltinImplSource::Misc), goal, structural_traits::instantiate_constituent_tys_for_copy_clone_trait, ) @@ -221,7 +226,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { fn consider_builtin_pointer_like_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { if goal.predicate.polarity != ty::PredicatePolarity::Positive { return Err(NoSolution); } @@ -234,14 +239,15 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { 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); + return ecx.forced_ambiguity(MaybeCause::Ambiguity); } 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 - ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc) + .enter(|ecx| ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)) } else { Err(NoSolution) } @@ -250,13 +256,15 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { fn consider_builtin_fn_ptr_trait_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { let self_ty = goal.predicate.self_ty(); match goal.predicate.polarity { // impl FnPtr for FnPtr {} ty::PredicatePolarity::Positive => { if self_ty.is_fn_ptr() { - ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc).enter(|ecx| { + ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + }) } else { Err(NoSolution) } @@ -266,7 +274,9 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { // If a type is rigid and not a fn ptr, then we know for certain // that it does *not* implement `FnPtr`. if !self_ty.is_fn_ptr() && self_ty.is_known_rigid() { - ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc).enter(|ecx| { + ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + }) } else { Err(NoSolution) } @@ -278,7 +288,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, goal_kind: ty::ClosureKind, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { if goal.predicate.polarity != ty::PredicatePolarity::Positive { return Err(NoSolution); } @@ -292,8 +302,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { )? { Some(a) => a, None => { - return ecx - .evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS); + return ecx.forced_ambiguity(MaybeCause::Ambiguity); } }; let output_is_sized_pred = tupled_inputs_and_output.map_bound(|(_, output)| { @@ -307,14 +316,20 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { .to_predicate(tcx); // A built-in `Fn` impl only holds if the output is sized. // (FIXME: technically we only need to check this if the type is a fn ptr...) - Self::consider_implied_clause(ecx, goal, pred, [goal.with(tcx, output_is_sized_pred)]) + Self::probe_and_consider_implied_clause( + ecx, + CandidateSource::BuiltinImpl(BuiltinImplSource::Misc), + goal, + pred, + [goal.with(tcx, output_is_sized_pred)], + ) } fn consider_builtin_async_fn_trait_candidates( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, goal_kind: ty::ClosureKind, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { if goal.predicate.polarity != ty::PredicatePolarity::Positive { return Err(NoSolution); } @@ -345,8 +360,9 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { .to_predicate(tcx); // A built-in `AsyncFn` impl only holds if the output is sized. // (FIXME: technically we only need to check this if the type is a fn ptr...) - Self::consider_implied_clause( + Self::probe_and_consider_implied_clause( ecx, + CandidateSource::BuiltinImpl(BuiltinImplSource::Misc), goal, pred, [goal.with(tcx, output_is_sized_pred)] @@ -358,7 +374,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { fn consider_builtin_async_fn_kind_helper_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { let [closure_fn_kind_ty, goal_kind_ty] = **goal.predicate.trait_ref.args else { bug!(); }; @@ -369,7 +385,8 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { }; let goal_kind = goal_kind_ty.expect_ty().to_opt_closure_kind().unwrap(); if closure_kind.extends(goal_kind) { - ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc) + .enter(|ecx| ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)) } else { Err(NoSolution) } @@ -384,13 +401,14 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { fn consider_builtin_tuple_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { if goal.predicate.polarity != ty::PredicatePolarity::Positive { return Err(NoSolution); } if let ty::Tuple(..) = goal.predicate.self_ty().kind() { - ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc) + .enter(|ecx| ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)) } else { Err(NoSolution) } @@ -399,18 +417,19 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { fn consider_builtin_pointee_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { if goal.predicate.polarity != ty::PredicatePolarity::Positive { return Err(NoSolution); } - ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc) + .enter(|ecx| ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)) } fn consider_builtin_future_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { if goal.predicate.polarity != ty::PredicatePolarity::Positive { return Err(NoSolution); } @@ -428,13 +447,15 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { // Async coroutine unconditionally implement `Future` // Technically, we need to check that the future output type is Sized, // but that's already proven by the coroutine being WF. - ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + // FIXME: use `consider_implied` + ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc) + .enter(|ecx| ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)) } fn consider_builtin_iterator_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { if goal.predicate.polarity != ty::PredicatePolarity::Positive { return Err(NoSolution); } @@ -452,13 +473,15 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { // Gen coroutines unconditionally implement `Iterator` // Technically, we need to check that the iterator output type is Sized, // but that's already proven by the coroutines being WF. - ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + // FIXME: use `consider_implied` + ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc) + .enter(|ecx| ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)) } fn consider_builtin_fused_iterator_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { if goal.predicate.polarity != ty::PredicatePolarity::Positive { return Err(NoSolution); } @@ -474,13 +497,15 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { } // Gen coroutines unconditionally implement `FusedIterator` - ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + // FIXME: use `consider_implied` + ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc) + .enter(|ecx| ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)) } fn consider_builtin_async_iterator_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { if goal.predicate.polarity != ty::PredicatePolarity::Positive { return Err(NoSolution); } @@ -498,13 +523,15 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { // Gen coroutines unconditionally implement `Iterator` // Technically, we need to check that the iterator output type is Sized, // but that's already proven by the coroutines being WF. - ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + // FIXME: use `consider_implied` + ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc) + .enter(|ecx| ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)) } fn consider_builtin_coroutine_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { if goal.predicate.polarity != ty::PredicatePolarity::Positive { return Err(NoSolution); } @@ -521,8 +548,9 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { } let coroutine = args.as_coroutine(); - Self::consider_implied_clause( + Self::probe_and_consider_implied_clause( ecx, + CandidateSource::BuiltinImpl(BuiltinImplSource::Misc), goal, ty::TraitRef::new(tcx, goal.predicate.def_id(), [self_ty, coroutine.resume_ty()]) .to_predicate(tcx), @@ -535,31 +563,33 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { fn consider_builtin_discriminant_kind_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { if goal.predicate.polarity != ty::PredicatePolarity::Positive { return Err(NoSolution); } // `DiscriminantKind` is automatically implemented for every type. - ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc) + .enter(|ecx| ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)) } fn consider_builtin_async_destruct_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { if goal.predicate.polarity != ty::PredicatePolarity::Positive { return Err(NoSolution); } // `AsyncDestruct` is automatically implemented for every type. - ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc) + .enter(|ecx| ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)) } fn consider_builtin_destruct_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { if goal.predicate.polarity != ty::PredicatePolarity::Positive { return Err(NoSolution); } @@ -568,13 +598,14 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { // `Destruct` is automatically implemented for every type in // non-const environments. - ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc) + .enter(|ecx| ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)) } fn consider_builtin_transmute_candidate( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { if goal.predicate.polarity != ty::PredicatePolarity::Positive { return Err(NoSolution); } @@ -594,11 +625,15 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { return Err(NoSolution); }; - let certainty = ecx.is_transmutable( - rustc_transmute::Types { dst: args.type_at(0), src: args.type_at(1) }, - assume, - )?; - ecx.evaluate_added_goals_and_make_canonical_response(certainty) + // FIXME: This actually should destructure the `Result` we get from transmutability and + // register candiates. We probably need to register >1 since we may have an OR of ANDs. + ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc).enter(|ecx| { + let certainty = ecx.is_transmutable( + rustc_transmute::Types { dst: args.type_at(0), src: args.type_at(1) }, + assume, + )?; + ecx.evaluate_added_goals_and_make_canonical_response(certainty) + }) } /// ```ignore (builtin impl example) @@ -611,20 +646,13 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { fn consider_structural_builtin_unsize_candidates( ecx: &mut EvalCtxt<'_, 'tcx>, goal: Goal<'tcx, Self>, - ) -> Vec<(CanonicalResponse<'tcx>, BuiltinImplSource)> { + ) -> Vec> { if goal.predicate.polarity != ty::PredicatePolarity::Positive { return vec![]; } - let misc_candidate = |ecx: &mut EvalCtxt<'_, 'tcx>, certainty| { - ( - ecx.evaluate_added_goals_and_make_canonical_response(certainty).unwrap(), - BuiltinImplSource::Misc, - ) - }; - - let result_to_single = |result, source| match result { - Ok(resp) => vec![(resp, source)], + let result_to_single = |result| match result { + Ok(resp) => vec![resp], Err(NoSolution) => vec![], }; @@ -642,7 +670,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { let goal = goal.with(ecx.tcx(), (a_ty, b_ty)); match (a_ty.kind(), b_ty.kind()) { (ty::Infer(ty::TyVar(..)), ..) => bug!("unexpected infer {a_ty:?} {b_ty:?}"), - (_, ty::Infer(ty::TyVar(..))) => vec![misc_candidate(ecx, Certainty::AMBIGUOUS)], + + (_, ty::Infer(ty::TyVar(..))) => { + result_to_single(ecx.forced_ambiguity(MaybeCause::Ambiguity)) + } // Trait upcasting, or `dyn Trait + Auto + 'a` -> `dyn Trait + 'b`. ( @@ -655,14 +686,12 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { // `T` -> `dyn Trait` unsizing. (_, &ty::Dynamic(b_region, b_data, ty::Dyn)) => result_to_single( ecx.consider_builtin_unsize_to_dyn_candidate(goal, b_region, b_data), - BuiltinImplSource::Misc, ), // `[T; N]` -> `[T]` unsizing - (&ty::Array(a_elem_ty, ..), &ty::Slice(b_elem_ty)) => result_to_single( - ecx.consider_builtin_array_unsize(goal, a_elem_ty, b_elem_ty), - BuiltinImplSource::Misc, - ), + (&ty::Array(a_elem_ty, ..), &ty::Slice(b_elem_ty)) => { + result_to_single(ecx.consider_builtin_array_unsize(goal, a_elem_ty, b_elem_ty)) + } // `Struct` -> `Struct` where `T: Unsize` (&ty::Adt(a_def, a_args), &ty::Adt(b_def, b_args)) @@ -670,7 +699,6 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { { result_to_single( ecx.consider_builtin_struct_unsize(goal, a_def, a_args, b_args), - BuiltinImplSource::Misc, ) } @@ -678,10 +706,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> { (&ty::Tuple(a_tys), &ty::Tuple(b_tys)) if a_tys.len() == b_tys.len() && !a_tys.is_empty() => { - result_to_single( - ecx.consider_builtin_tuple_unsize(goal, a_tys, b_tys), - BuiltinImplSource::TupleUnsizing, - ) + result_to_single(ecx.consider_builtin_tuple_unsize(goal, a_tys, b_tys)) } _ => vec![], @@ -707,7 +732,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { a_region: ty::Region<'tcx>, b_data: &'tcx ty::List>, b_region: ty::Region<'tcx>, - ) -> Vec<(CanonicalResponse<'tcx>, BuiltinImplSource)> { + ) -> Vec> { let tcx = self.tcx(); let Goal { predicate: (a_ty, _b_ty), .. } = goal; @@ -715,35 +740,32 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { // If the principal def ids match (or are both none), then we're not doing // trait upcasting. We're just removing auto traits (or shortening the lifetime). if a_data.principal_def_id() == b_data.principal_def_id() { - if let Ok(resp) = self.consider_builtin_upcast_to_principal( + responses.extend(self.consider_builtin_upcast_to_principal( goal, + CandidateSource::BuiltinImpl(BuiltinImplSource::Misc), a_data, a_region, b_data, b_region, a_data.principal(), - ) { - responses.push((resp, BuiltinImplSource::Misc)); - } + )); } else if let Some(a_principal) = a_data.principal() { self.walk_vtable( a_principal.with_self_ty(tcx, a_ty), |ecx, new_a_principal, _, vtable_vptr_slot| { - if let Ok(resp) = ecx.probe_misc_candidate("dyn upcast").enter(|ecx| { - ecx.consider_builtin_upcast_to_principal( - goal, - a_data, - a_region, - b_data, - b_region, - Some(new_a_principal.map_bound(|trait_ref| { - ty::ExistentialTraitRef::erase_self_ty(tcx, trait_ref) - })), - ) - }) { - responses - .push((resp, BuiltinImplSource::TraitUpcasting { vtable_vptr_slot })); - } + responses.extend(ecx.consider_builtin_upcast_to_principal( + goal, + CandidateSource::BuiltinImpl(BuiltinImplSource::TraitUpcasting { + vtable_vptr_slot, + }), + a_data, + a_region, + b_data, + b_region, + Some(new_a_principal.map_bound(|trait_ref| { + ty::ExistentialTraitRef::erase_self_ty(tcx, trait_ref) + })), + )); }, ); } @@ -756,7 +778,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { goal: Goal<'tcx, (Ty<'tcx>, Ty<'tcx>)>, b_data: &'tcx ty::List>, b_region: ty::Region<'tcx>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { let tcx = self.tcx(); let Goal { predicate: (a_ty, _), .. } = goal; @@ -765,37 +787,40 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { return Err(NoSolution); } - // Check that the type implements all of the predicates of the trait object. - // (i.e. the principal, all of the associated types match, and any auto traits) - self.add_goals( - GoalSource::ImplWhereBound, - b_data.iter().map(|pred| goal.with(tcx, pred.with_self_ty(tcx, a_ty))), - ); - - // The type must be `Sized` to be unsized. - if let Some(sized_def_id) = tcx.lang_items().sized_trait() { - self.add_goal( + self.probe_builtin_trait_candidate(BuiltinImplSource::Misc).enter(|ecx| { + // Check that the type implements all of the predicates of the trait object. + // (i.e. the principal, all of the associated types match, and any auto traits) + ecx.add_goals( GoalSource::ImplWhereBound, - goal.with(tcx, ty::TraitRef::new(tcx, sized_def_id, [a_ty])), + b_data.iter().map(|pred| goal.with(tcx, pred.with_self_ty(tcx, a_ty))), ); - } else { - return Err(NoSolution); - } - // The type must outlive the lifetime of the `dyn` we're unsizing into. - self.add_goal(GoalSource::Misc, goal.with(tcx, ty::OutlivesPredicate(a_ty, b_region))); - self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + // The type must be `Sized` to be unsized. + if let Some(sized_def_id) = tcx.lang_items().sized_trait() { + ecx.add_goal( + GoalSource::ImplWhereBound, + goal.with(tcx, ty::TraitRef::new(tcx, sized_def_id, [a_ty])), + ); + } else { + return Err(NoSolution); + } + + // The type must outlive the lifetime of the `dyn` we're unsizing into. + ecx.add_goal(GoalSource::Misc, goal.with(tcx, ty::OutlivesPredicate(a_ty, b_region))); + ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + }) } fn consider_builtin_upcast_to_principal( &mut self, goal: Goal<'tcx, (Ty<'tcx>, Ty<'tcx>)>, + source: CandidateSource, a_data: &'tcx ty::List>, a_region: ty::Region<'tcx>, b_data: &'tcx ty::List>, b_region: ty::Region<'tcx>, upcast_principal: Option>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { let param_env = goal.param_env; // We may upcast to auto traits that are either explicitly listed in @@ -814,7 +839,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { // having any inference side-effects. We process obligations because // unification may initially succeed due to deferred projection equality. let projection_may_match = - |ecx: &mut Self, + |ecx: &mut EvalCtxt<'_, 'tcx>, source_projection: ty::PolyExistentialProjection<'tcx>, target_projection: ty::PolyExistentialProjection<'tcx>| { source_projection.item_def_id() == target_projection.item_def_id() @@ -828,54 +853,60 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { .is_ok() }; - for bound in b_data { - match bound.skip_binder() { - // Check that a's supertrait (upcast_principal) is compatible - // with the target (b_ty). - ty::ExistentialPredicate::Trait(target_principal) => { - self.eq(param_env, upcast_principal.unwrap(), bound.rebind(target_principal))?; - } - // Check that b_ty's projection is satisfied by exactly one of - // a_ty's projections. First, we look through the list to see if - // any match. If not, error. Then, if *more* than one matches, we - // return ambiguity. Otherwise, if exactly one matches, equate - // it with b_ty's projection. - ty::ExistentialPredicate::Projection(target_projection) => { - let target_projection = bound.rebind(target_projection); - let mut matching_projections = - a_data.projection_bounds().filter(|source_projection| { - projection_may_match(self, *source_projection, target_projection) - }); - let Some(source_projection) = matching_projections.next() else { - return Err(NoSolution); - }; - if matching_projections.next().is_some() { - return self.evaluate_added_goals_and_make_canonical_response( - Certainty::AMBIGUOUS, - ); + self.probe_trait_candidate(source).enter(|ecx| { + for bound in b_data { + match bound.skip_binder() { + // Check that a's supertrait (upcast_principal) is compatible + // with the target (b_ty). + ty::ExistentialPredicate::Trait(target_principal) => { + ecx.eq( + param_env, + upcast_principal.unwrap(), + bound.rebind(target_principal), + )?; } - self.eq(param_env, source_projection, target_projection)?; - } - // Check that b_ty's auto traits are present in a_ty's bounds. - ty::ExistentialPredicate::AutoTrait(def_id) => { - if !a_auto_traits.contains(&def_id) { - return Err(NoSolution); + // Check that b_ty's projection is satisfied by exactly one of + // a_ty's projections. First, we look through the list to see if + // any match. If not, error. Then, if *more* than one matches, we + // return ambiguity. Otherwise, if exactly one matches, equate + // it with b_ty's projection. + ty::ExistentialPredicate::Projection(target_projection) => { + let target_projection = bound.rebind(target_projection); + let mut matching_projections = + a_data.projection_bounds().filter(|source_projection| { + projection_may_match(ecx, *source_projection, target_projection) + }); + let Some(source_projection) = matching_projections.next() else { + return Err(NoSolution); + }; + if matching_projections.next().is_some() { + return ecx.evaluate_added_goals_and_make_canonical_response( + Certainty::AMBIGUOUS, + ); + } + ecx.eq(param_env, source_projection, target_projection)?; + } + // Check that b_ty's auto traits are present in a_ty's bounds. + ty::ExistentialPredicate::AutoTrait(def_id) => { + if !a_auto_traits.contains(&def_id) { + return Err(NoSolution); + } } } } - } - // Also require that a_ty's lifetime outlives b_ty's lifetime. - self.add_goal( - GoalSource::ImplWhereBound, - Goal::new( - self.tcx(), - param_env, - ty::Binder::dummy(ty::OutlivesPredicate(a_region, b_region)), - ), - ); + // Also require that a_ty's lifetime outlives b_ty's lifetime. + ecx.add_goal( + GoalSource::ImplWhereBound, + Goal::new( + ecx.tcx(), + param_env, + ty::Binder::dummy(ty::OutlivesPredicate(a_region, b_region)), + ), + ); - self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + }) } /// We have the following builtin impls for arrays: @@ -891,9 +922,10 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { goal: Goal<'tcx, (Ty<'tcx>, Ty<'tcx>)>, a_elem_ty: Ty<'tcx>, b_elem_ty: Ty<'tcx>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { self.eq(goal.param_env, a_elem_ty, b_elem_ty)?; - self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + self.probe_builtin_trait_candidate(BuiltinImplSource::Misc) + .enter(|ecx| ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)) } /// We generate a builtin `Unsize` impls for structs with generic parameters only @@ -915,7 +947,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { def: ty::AdtDef<'tcx>, a_args: ty::GenericArgsRef<'tcx>, b_args: ty::GenericArgsRef<'tcx>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { let tcx = self.tcx(); let Goal { predicate: (_a_ty, b_ty), .. } = goal; @@ -957,7 +989,8 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { ), ), ); - self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + self.probe_builtin_trait_candidate(BuiltinImplSource::Misc) + .enter(|ecx| ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)) } /// We generate the following builtin impl for tuples of all sizes. @@ -975,7 +1008,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { goal: Goal<'tcx, (Ty<'tcx>, Ty<'tcx>)>, a_tys: &'tcx ty::List>, b_tys: &'tcx ty::List>, - ) -> QueryResult<'tcx> { + ) -> Result, NoSolution> { let tcx = self.tcx(); let Goal { predicate: (_a_ty, b_ty), .. } = goal; @@ -999,7 +1032,8 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { ), ), ); - self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + self.probe_builtin_trait_candidate(BuiltinImplSource::TupleUnsizing) + .enter(|ecx| ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)) } // Return `Some` if there is an impl (built-in or user provided) that may @@ -1009,7 +1043,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { fn disqualify_auto_trait_candidate_due_to_possible_impl( &mut self, goal: Goal<'tcx, TraitPredicate<'tcx>>, - ) -> Option> { + ) -> Option, NoSolution>> { let self_ty = goal.predicate.self_ty(); match *self_ty.kind() { // Stall int and float vars until they are resolved to a concrete @@ -1018,7 +1052,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { // we probably don't want to treat an `impl !AutoTrait for i32` as // disqualifying the built-in auto impl for `i64: AutoTrait` either. ty::Infer(ty::IntVar(_) | ty::FloatVar(_)) => { - Some(self.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS)) + Some(self.forced_ambiguity(MaybeCause::Ambiguity)) } // These types cannot be structurally decomposed into constituent @@ -1039,9 +1073,11 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { { match self.tcx().coroutine_movability(def_id) { Movability::Static => Some(Err(NoSolution)), - Movability::Movable => { - Some(self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)) - } + Movability::Movable => Some( + self.probe_builtin_trait_candidate(BuiltinImplSource::Misc).enter(|ecx| { + ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + }), + ), } } @@ -1106,13 +1142,14 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { /// wrapped in one. fn probe_and_evaluate_goal_for_constituent_tys( &mut self, + source: CandidateSource, goal: Goal<'tcx, TraitPredicate<'tcx>>, constituent_tys: impl Fn( &EvalCtxt<'_, 'tcx>, Ty<'tcx>, ) -> Result>>, NoSolution>, - ) -> QueryResult<'tcx> { - self.probe_misc_candidate("constituent tys").enter(|ecx| { + ) -> Result, NoSolution> { + self.probe_trait_candidate(source).enter(|ecx| { ecx.add_goals( GoalSource::ImplWhereBound, constituent_tys(ecx, goal.predicate.self_ty())? diff --git a/compiler/rustc_trait_selection/src/traits/coherence.rs b/compiler/rustc_trait_selection/src/traits/coherence.rs index a4208cdc3c62c..c430da10b0cbf 100644 --- a/compiler/rustc_trait_selection/src/traits/coherence.rs +++ b/compiler/rustc_trait_selection/src/traits/coherence.rs @@ -1078,9 +1078,8 @@ impl<'a, 'tcx> ProofTreeVisitor<'tcx> for AmbiguityCausesVisitor<'a, 'tcx> { // Add ambiguity causes for unknowable goals. let mut ambiguity_cause = None; for cand in goal.candidates() { - // FIXME: boiiii, using string comparisions here sure is scuffed. - if let inspect::ProbeKind::MiscCandidate { - name: "coherence unknowable", + if let inspect::ProbeKind::TraitCandidate { + source: CandidateSource::CoherenceUnknowable, result: Ok(_), } = cand.kind() {