diff options
Diffstat (limited to 'compiler/rustc_trait_selection/src')
22 files changed, 1281 insertions, 830 deletions
diff --git a/compiler/rustc_trait_selection/src/errors.rs b/compiler/rustc_trait_selection/src/errors.rs index 7894f8dd98f..20cd573f46e 100644 --- a/compiler/rustc_trait_selection/src/errors.rs +++ b/compiler/rustc_trait_selection/src/errors.rs @@ -1,7 +1,7 @@ use crate::fluent_generated as fluent; use rustc_errors::{ codes::*, AddToDiagnostic, Applicability, DiagCtxt, Diagnostic, DiagnosticBuilder, - EmissionGuarantee, IntoDiagnostic, Level, SubdiagnosticMessage, + EmissionGuarantee, IntoDiagnostic, Level, SubdiagnosticMessageOp, }; use rustc_macros::Diagnostic; use rustc_middle::ty::{self, ClosureKind, PolyTraitRef, Ty}; @@ -102,10 +102,7 @@ pub enum AdjustSignatureBorrow { } impl AddToDiagnostic for AdjustSignatureBorrow { - fn add_to_diagnostic_with<F>(self, diag: &mut Diagnostic, _: F) - where - F: Fn(&mut Diagnostic, SubdiagnosticMessage) -> SubdiagnosticMessage, - { + fn add_to_diagnostic_with<F: SubdiagnosticMessageOp>(self, diag: &mut Diagnostic, _: F) { match self { AdjustSignatureBorrow::Borrow { to_borrow } => { diag.arg("len", to_borrow.len()); diff --git a/compiler/rustc_trait_selection/src/lib.rs b/compiler/rustc_trait_selection/src/lib.rs index 5ec45212bc7..00a2adccf64 100644 --- a/compiler/rustc_trait_selection/src/lib.rs +++ b/compiler/rustc_trait_selection/src/lib.rs @@ -14,6 +14,8 @@ #![doc(rust_logo)] #![feature(rustdoc_internals)] #![allow(internal_features)] +#![allow(rustc::diagnostic_outside_of_impl)] +#![allow(rustc::untranslatable_diagnostic)] #![feature(associated_type_bounds)] #![feature(box_patterns)] #![feature(control_flow_enum)] @@ -22,7 +24,7 @@ #![feature(option_take_if)] #![feature(never_type)] #![feature(type_alias_impl_trait)] -#![feature(min_specialization)] +#![cfg_attr(bootstrap, feature(min_specialization))] #![recursion_limit = "512"] // For rustdoc #[macro_use] diff --git a/compiler/rustc_trait_selection/src/solve/assembly/mod.rs b/compiler/rustc_trait_selection/src/solve/assembly/mod.rs index 7052fd776b0..81c0cfea85a 100644 --- a/compiler/rustc_trait_selection/src/solve/assembly/mod.rs +++ b/compiler/rustc_trait_selection/src/solve/assembly/mod.rs @@ -8,7 +8,7 @@ use rustc_infer::traits::query::NoSolution; use rustc_infer::traits::Reveal; use rustc_middle::traits::solve::inspect::ProbeKind; use rustc_middle::traits::solve::{ - CandidateSource, CanonicalResponse, Certainty, Goal, QueryResult, + CandidateSource, CanonicalResponse, Certainty, Goal, MaybeCause, QueryResult, }; use rustc_middle::traits::BuiltinImplSource; use rustc_middle::ty::fast_reject::{SimplifiedType, TreatParams}; @@ -276,25 +276,16 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { &mut self, goal: Goal<'tcx, G>, ) -> Vec<Candidate<'tcx>> { - let dummy_candidate = |this: &mut EvalCtxt<'_, 'tcx>, certainty| { - let source = CandidateSource::BuiltinImpl(BuiltinImplSource::Misc); - let result = this.evaluate_added_goals_and_make_canonical_response(certainty).unwrap(); - let mut dummy_probe = this.inspect.new_probe(); - dummy_probe.probe_kind(ProbeKind::TraitCandidate { source, result: Ok(result) }); - this.inspect.finish_probe(dummy_probe); - vec![Candidate { source, result }] - }; - let Some(normalized_self_ty) = self.try_normalize_ty(goal.param_env, goal.predicate.self_ty()) else { debug!("overflow while evaluating self type"); - return dummy_candidate(self, Certainty::OVERFLOW); + return self.forced_ambiguity(MaybeCause::Overflow); }; if normalized_self_ty.is_ty_var() { debug!("self type has been normalized to infer"); - return dummy_candidate(self, Certainty::AMBIGUOUS); + return self.forced_ambiguity(MaybeCause::Ambiguity); } let goal = @@ -315,11 +306,26 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { self.assemble_param_env_candidates(goal, &mut candidates); - self.assemble_coherence_unknowable_candidates(goal, &mut candidates); + match self.solver_mode() { + SolverMode::Normal => self.discard_impls_shadowed_by_env(goal, &mut candidates), + SolverMode::Coherence => { + self.assemble_coherence_unknowable_candidates(goal, &mut candidates) + } + } candidates } + fn forced_ambiguity(&mut self, cause: MaybeCause) -> Vec<Candidate<'tcx>> { + let source = CandidateSource::BuiltinImpl(BuiltinImplSource::Misc); + let certainty = Certainty::Maybe(cause); + let result = self.evaluate_added_goals_and_make_canonical_response(certainty).unwrap(); + let mut dummy_probe = self.inspect.new_probe(); + dummy_probe.probe_kind(ProbeKind::TraitCandidate { source, result: Ok(result) }); + self.inspect.finish_probe(dummy_probe); + vec![Candidate { source, result }] + } + #[instrument(level = "debug", skip_all)] fn assemble_non_blanket_impl_candidates<G: GoalKind<'tcx>>( &mut self, @@ -542,7 +548,27 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { goal: Goal<'tcx, G>, candidates: &mut Vec<Candidate<'tcx>>, ) { - let alias_ty = match goal.predicate.self_ty().kind() { + let () = self.probe(|_| ProbeKind::NormalizedSelfTyAssembly).enter(|ecx| { + ecx.assemble_alias_bound_candidates_recur(goal.predicate.self_ty(), goal, candidates); + }); + } + + /// For some deeply nested `<T>::A::B::C::D` rigid associated type, + /// we should explore the item bounds for all levels, since the + /// `associated_type_bounds` feature means that a parent associated + /// type may carry bounds for a nested associated type. + /// + /// If we have a projection, check that its self type is a rigid projection. + /// If so, continue searching by recursively calling after normalization. + // FIXME: This may recurse infinitely, but I can't seem to trigger it without + // hitting another overflow error something. Add a depth parameter needed later. + fn assemble_alias_bound_candidates_recur<G: GoalKind<'tcx>>( + &mut self, + self_ty: Ty<'tcx>, + goal: Goal<'tcx, G>, + candidates: &mut Vec<Candidate<'tcx>>, + ) { + let (kind, alias_ty) = match *self_ty.kind() { ty::Bool | ty::Char | ty::Int(_) @@ -567,13 +593,27 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { | ty::Param(_) | ty::Placeholder(..) | ty::Infer(ty::IntVar(_) | ty::FloatVar(_)) - | ty::Alias(ty::Inherent, _) - | ty::Alias(ty::Weak, _) | ty::Error(_) => return, - ty::Infer(ty::TyVar(_) | ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_)) - | ty::Bound(..) => bug!("unexpected self type for `{goal:?}`"), - // Excluding IATs and type aliases here as they don't have meaningful item bounds. - ty::Alias(ty::Projection | ty::Opaque, alias_ty) => alias_ty, + ty::Infer(ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_)) | ty::Bound(..) => { + bug!("unexpected self type for `{goal:?}`") + } + + ty::Infer(ty::TyVar(_)) => { + // If we hit infer when normalizing the self type of an alias, + // then bail with ambiguity. We should never encounter this on + // the *first* iteration of this recursive function. + if let Ok(result) = + self.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS) + { + candidates.push(Candidate { source: CandidateSource::AliasBound, result }); + } + return; + } + + ty::Alias(kind @ (ty::Projection | ty::Opaque), alias_ty) => (kind, alias_ty), + ty::Alias(ty::Inherent | ty::Weak, _) => { + unreachable!("Weak and Inherent aliases should have been normalized away already") + } }; for assumption in @@ -581,9 +621,28 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { { match G::consider_alias_bound_candidate(self, goal, assumption) { Ok(result) => { - candidates.push(Candidate { source: CandidateSource::AliasBound, result }) + candidates.push(Candidate { source: CandidateSource::AliasBound, result }); + } + Err(NoSolution) => {} + } + } + + if kind != ty::Projection { + return; + } + + match self.try_normalize_ty(goal.param_env, alias_ty.self_ty()) { + // Recurse on the self type of the projection. + Some(next_self_ty) => { + self.assemble_alias_bound_candidates_recur(next_self_ty, goal, candidates); + } + // Bail if we overflow when normalizing, adding an ambiguous candidate. + None => { + if let Ok(result) = + self.evaluate_added_goals_and_make_canonical_response(Certainty::OVERFLOW) + { + candidates.push(Candidate { source: CandidateSource::AliasBound, result }); } - Err(NoSolution) => (), } } } @@ -779,6 +838,12 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { } } + /// In coherence we have to not only care about all impls we know about, but + /// also consider impls which may get added in a downstream or sibling crate + /// or which an upstream impl may add in a minor release. + /// + /// To do so we add an ambiguous candidate in case such an unknown impl could + /// apply to the current goal. #[instrument(level = "debug", skip_all)] fn assemble_coherence_unknowable_candidates<G: GoalKind<'tcx>>( &mut self, @@ -786,11 +851,6 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { candidates: &mut Vec<Candidate<'tcx>>, ) { let tcx = self.tcx(); - match self.solver_mode() { - SolverMode::Normal => return, - SolverMode::Coherence => {} - }; - let result = self.probe_misc_candidate("coherence unknowable").enter(|ecx| { let trait_ref = goal.predicate.trait_ref(tcx); #[derive(Debug)] @@ -820,46 +880,65 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { } } + /// If there's a where-bound for the current goal, do not use any impl candidates + /// to prove the current goal. Most importantly, if there is a where-bound which does + /// not specify any associated types, we do not allow normalizing the associated type + /// by using an impl, even if it would apply. + /// + /// <https://github.com/rust-lang/trait-system-refactor-initiative/issues/76> + // FIXME(@lcnr): The current structure here makes me unhappy and feels ugly. idk how + // to improve this however. However, this should make it fairly straightforward to refine + // the filtering going forward, so it seems alright-ish for now. + fn discard_impls_shadowed_by_env<G: GoalKind<'tcx>>( + &mut self, + goal: Goal<'tcx, G>, + candidates: &mut Vec<Candidate<'tcx>>, + ) { + let tcx = self.tcx(); + let trait_goal: Goal<'tcx, ty::TraitPredicate<'tcx>> = + goal.with(tcx, goal.predicate.trait_ref(tcx)); + let mut trait_candidates_from_env = Vec::new(); + self.assemble_param_env_candidates(trait_goal, &mut trait_candidates_from_env); + self.assemble_alias_bound_candidates(trait_goal, &mut trait_candidates_from_env); + if !trait_candidates_from_env.is_empty() { + let trait_env_result = self.merge_candidates(trait_candidates_from_env); + match trait_env_result.unwrap().value.certainty { + // If proving the trait goal succeeds by using the env, + // we freely drop all impl candidates. + // + // FIXME(@lcnr): It feels like this could easily hide + // a forced ambiguity candidate added earlier. + // This feels dangerous. + Certainty::Yes => { + candidates.retain(|c| match c.source { + CandidateSource::Impl(_) | CandidateSource::BuiltinImpl(_) => false, + CandidateSource::ParamEnv(_) | CandidateSource::AliasBound => true, + }); + } + // If it is still ambiguous we instead just force the whole goal + // to be ambig and wait for inference constraints. See + // tests/ui/traits/next-solver/env-shadows-impls/ambig-env-no-shadow.rs + Certainty::Maybe(cause) => { + *candidates = self.forced_ambiguity(cause); + } + } + } + } + /// If there are multiple ways to prove a trait or projection goal, we have /// to somehow try to merge the candidates into one. If that fails, we return /// ambiguity. #[instrument(level = "debug", skip(self), ret)] pub(super) fn merge_candidates( &mut self, - mut candidates: Vec<Candidate<'tcx>>, + candidates: Vec<Candidate<'tcx>>, ) -> QueryResult<'tcx> { // First try merging all candidates. This is complete and fully sound. let responses = candidates.iter().map(|c| c.result).collect::<Vec<_>>(); if let Some(result) = self.try_merge_responses(&responses) { return Ok(result); + } else { + self.flounder(&responses) } - - // We then check whether we should prioritize `ParamEnv` candidates. - // - // Doing so is incomplete and would therefore be unsound during coherence. - match self.solver_mode() { - SolverMode::Coherence => (), - // Prioritize `ParamEnv` candidates only if they do not guide inference. - // - // This is still incomplete as we may add incorrect region bounds. - SolverMode::Normal => { - let param_env_responses = candidates - .iter() - .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) { - // 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); - } - } - } - self.flounder(&responses) } } 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 d02578c4846..819b070cf8b 100644 --- a/compiler/rustc_trait_selection/src/solve/assembly/structural_traits.rs +++ b/compiler/rustc_trait_selection/src/solve/assembly/structural_traits.rs @@ -20,7 +20,7 @@ use crate::solve::EvalCtxt; pub(in crate::solve) fn instantiate_constituent_tys_for_auto_trait<'tcx>( ecx: &EvalCtxt<'_, 'tcx>, ty: Ty<'tcx>, -) -> Result<Vec<Ty<'tcx>>, NoSolution> { +) -> Result<Vec<ty::Binder<'tcx, Ty<'tcx>>>, NoSolution> { let tcx = ecx.tcx(); match *ty.kind() { ty::Uint(_) @@ -34,7 +34,7 @@ pub(in crate::solve) fn instantiate_constituent_tys_for_auto_trait<'tcx>( | ty::Char => Ok(vec![]), // Treat `str` like it's defined as `struct str([u8]);` - ty::Str => Ok(vec![Ty::new_slice(tcx, tcx.types.u8)]), + ty::Str => Ok(vec![ty::Binder::dummy(Ty::new_slice(tcx, tcx.types.u8))]), ty::Dynamic(..) | ty::Param(..) @@ -47,46 +47,48 @@ pub(in crate::solve) fn instantiate_constituent_tys_for_auto_trait<'tcx>( } ty::RawPtr(ty::TypeAndMut { ty: element_ty, .. }) | ty::Ref(_, element_ty, _) => { - Ok(vec![element_ty]) + Ok(vec![ty::Binder::dummy(element_ty)]) } - ty::Array(element_ty, _) | ty::Slice(element_ty) => Ok(vec![element_ty]), + ty::Array(element_ty, _) | ty::Slice(element_ty) => Ok(vec![ty::Binder::dummy(element_ty)]), ty::Tuple(tys) => { // (T1, ..., Tn) -- meets any bound that all of T1...Tn meet - Ok(tys.iter().collect()) + Ok(tys.iter().map(ty::Binder::dummy).collect()) } - ty::Closure(_, args) => Ok(vec![args.as_closure().tupled_upvars_ty()]), + ty::Closure(_, args) => Ok(vec![ty::Binder::dummy(args.as_closure().tupled_upvars_ty())]), - ty::CoroutineClosure(_, args) => Ok(vec![args.as_coroutine_closure().tupled_upvars_ty()]), + ty::CoroutineClosure(_, args) => { + Ok(vec![ty::Binder::dummy(args.as_coroutine_closure().tupled_upvars_ty())]) + } ty::Coroutine(_, args) => { let coroutine_args = args.as_coroutine(); - Ok(vec![coroutine_args.tupled_upvars_ty(), coroutine_args.witness()]) + Ok(vec![ + ty::Binder::dummy(coroutine_args.tupled_upvars_ty()), + ty::Binder::dummy(coroutine_args.witness()), + ]) } ty::CoroutineWitness(def_id, args) => Ok(ecx .tcx() .coroutine_hidden_types(def_id) - .map(|bty| { - ecx.instantiate_binder_with_placeholders(replace_erased_lifetimes_with_bound_vars( - tcx, - bty.instantiate(tcx, args), - )) - }) + .map(|bty| replace_erased_lifetimes_with_bound_vars(tcx, bty.instantiate(tcx, args))) .collect()), // For `PhantomData<T>`, we pass `T`. - ty::Adt(def, args) if def.is_phantom_data() => Ok(vec![args.type_at(0)]), + ty::Adt(def, args) if def.is_phantom_data() => Ok(vec![ty::Binder::dummy(args.type_at(0))]), - ty::Adt(def, args) => Ok(def.all_fields().map(|f| f.ty(tcx, args)).collect()), + ty::Adt(def, args) => { + Ok(def.all_fields().map(|f| ty::Binder::dummy(f.ty(tcx, args))).collect()) + } ty::Alias(ty::Opaque, ty::AliasTy { def_id, args, .. }) => { // We can resolve the `impl Trait` to its concrete type, // which enforces a DAG between the functions requiring // the auto trait bounds in question. - Ok(vec![tcx.type_of(def_id).instantiate(tcx, args)]) + Ok(vec![ty::Binder::dummy(tcx.type_of(def_id).instantiate(tcx, args))]) } } } @@ -116,7 +118,7 @@ pub(in crate::solve) fn replace_erased_lifetimes_with_bound_vars<'tcx>( pub(in crate::solve) fn instantiate_constituent_tys_for_sized_trait<'tcx>( ecx: &EvalCtxt<'_, 'tcx>, ty: Ty<'tcx>, -) -> Result<Vec<Ty<'tcx>>, NoSolution> { +) -> Result<Vec<ty::Binder<'tcx, Ty<'tcx>>>, NoSolution> { match *ty.kind() { ty::Infer(ty::IntVar(_) | ty::FloatVar(_)) | ty::Uint(_) @@ -150,11 +152,11 @@ pub(in crate::solve) fn instantiate_constituent_tys_for_sized_trait<'tcx>( bug!("unexpected type `{ty}`") } - ty::Tuple(tys) => Ok(tys.to_vec()), + ty::Tuple(tys) => Ok(tys.iter().map(ty::Binder::dummy).collect()), ty::Adt(def, args) => { let sized_crit = def.sized_constraint(ecx.tcx()); - Ok(sized_crit.iter_instantiated(ecx.tcx(), args).collect()) + Ok(sized_crit.iter_instantiated(ecx.tcx(), args).map(ty::Binder::dummy).collect()) } } } @@ -163,7 +165,7 @@ pub(in crate::solve) fn instantiate_constituent_tys_for_sized_trait<'tcx>( pub(in crate::solve) fn instantiate_constituent_tys_for_copy_clone_trait<'tcx>( ecx: &EvalCtxt<'_, 'tcx>, ty: Ty<'tcx>, -) -> Result<Vec<Ty<'tcx>>, NoSolution> { +) -> Result<Vec<ty::Binder<'tcx, Ty<'tcx>>>, NoSolution> { match *ty.kind() { ty::FnDef(..) | ty::FnPtr(_) | ty::Error(_) => Ok(vec![]), @@ -194,9 +196,9 @@ pub(in crate::solve) fn instantiate_constituent_tys_for_copy_clone_trait<'tcx>( bug!("unexpected type `{ty}`") } - ty::Tuple(tys) => Ok(tys.to_vec()), + ty::Tuple(tys) => Ok(tys.iter().map(ty::Binder::dummy).collect()), - ty::Closure(_, args) => Ok(vec![args.as_closure().tupled_upvars_ty()]), + ty::Closure(_, args) => Ok(vec![ty::Binder::dummy(args.as_closure().tupled_upvars_ty())]), ty::CoroutineClosure(..) => Err(NoSolution), @@ -205,7 +207,10 @@ pub(in crate::solve) fn instantiate_constituent_tys_for_copy_clone_trait<'tcx>( Movability::Movable => { if ecx.tcx().features().coroutine_clone { let coroutine = args.as_coroutine(); - Ok(vec![coroutine.tupled_upvars_ty(), coroutine.witness()]) + Ok(vec![ + ty::Binder::dummy(coroutine.tupled_upvars_ty()), + ty::Binder::dummy(coroutine.witness()), + ]) } else { Err(NoSolution) } @@ -216,10 +221,10 @@ pub(in crate::solve) fn instantiate_constituent_tys_for_copy_clone_trait<'tcx>( .tcx() .coroutine_hidden_types(def_id) .map(|bty| { - ecx.instantiate_binder_with_placeholders(replace_erased_lifetimes_with_bound_vars( + replace_erased_lifetimes_with_bound_vars( ecx.tcx(), bty.instantiate(ecx.tcx(), args), - )) + ) }) .collect()), } @@ -318,34 +323,27 @@ pub(in crate::solve) fn extract_tupled_inputs_and_output_from_async_callable<'tc self_ty: Ty<'tcx>, goal_kind: ty::ClosureKind, env_region: ty::Region<'tcx>, -) -> Result< - (ty::Binder<'tcx, (Ty<'tcx>, Ty<'tcx>, Ty<'tcx>)>, Option<ty::Predicate<'tcx>>), - NoSolution, -> { +) -> Result<(ty::Binder<'tcx, (Ty<'tcx>, Ty<'tcx>, Ty<'tcx>)>, Vec<ty::Predicate<'tcx>>), NoSolution> +{ match *self_ty.kind() { ty::CoroutineClosure(def_id, args) => { let args = args.as_coroutine_closure(); let kind_ty = args.kind_ty(); - - if let Some(closure_kind) = kind_ty.to_opt_closure_kind() { + let sig = args.coroutine_closure_sig().skip_binder(); + let mut nested = vec![]; + let coroutine_ty = if let Some(closure_kind) = kind_ty.to_opt_closure_kind() { if !closure_kind.extends(goal_kind) { return Err(NoSolution); } - Ok(( - args.coroutine_closure_sig().map_bound(|sig| { - let coroutine_ty = sig.to_coroutine_given_kind_and_upvars( - tcx, - args.parent_args(), - tcx.coroutine_for_closure(def_id), - goal_kind, - env_region, - args.tupled_upvars_ty(), - args.coroutine_captures_by_ref_ty(), - ); - (sig.tupled_inputs_ty, sig.return_ty, coroutine_ty) - }), - None, - )) + sig.to_coroutine_given_kind_and_upvars( + tcx, + args.parent_args(), + tcx.coroutine_for_closure(def_id), + goal_kind, + env_region, + args.tupled_upvars_ty(), + args.coroutine_captures_by_ref_ty(), + ) } else { let async_fn_kind_trait_def_id = tcx.require_lang_item(LangItem::AsyncFnKindHelper, None); @@ -362,42 +360,117 @@ pub(in crate::solve) fn extract_tupled_inputs_and_output_from_async_callable<'tc // the goal kind <= the closure kind. As a projection `AsyncFnKindHelper::Upvars` // will project to the right upvars for the generator, appending the inputs and // coroutine upvars respecting the closure kind. - Ok(( - args.coroutine_closure_sig().map_bound(|sig| { - let tupled_upvars_ty = Ty::new_projection( - tcx, - upvars_projection_def_id, - [ - ty::GenericArg::from(kind_ty), - Ty::from_closure_kind(tcx, goal_kind).into(), - env_region.into(), - sig.tupled_inputs_ty.into(), - args.tupled_upvars_ty().into(), - args.coroutine_captures_by_ref_ty().into(), - ], - ); - let coroutine_ty = sig.to_coroutine( - tcx, - args.parent_args(), - Ty::from_closure_kind(tcx, goal_kind), - tcx.coroutine_for_closure(def_id), - tupled_upvars_ty, - ); - (sig.tupled_inputs_ty, sig.return_ty, coroutine_ty) - }), - Some( - ty::TraitRef::new( - tcx, - async_fn_kind_trait_def_id, - [kind_ty, Ty::from_closure_kind(tcx, goal_kind)], - ) - .to_predicate(tcx), - ), - )) - } + nested.push( + ty::TraitRef::new( + tcx, + async_fn_kind_trait_def_id, + [kind_ty, Ty::from_closure_kind(tcx, goal_kind)], + ) + .to_predicate(tcx), + ); + let tupled_upvars_ty = Ty::new_projection( + tcx, + upvars_projection_def_id, + [ + ty::GenericArg::from(kind_ty), + Ty::from_closure_kind(tcx, goal_kind).into(), + env_region.into(), + sig.tupled_inputs_ty.into(), + args.tupled_upvars_ty().into(), + args.coroutine_captures_by_ref_ty().into(), + ], + ); + sig.to_coroutine( + tcx, + args.parent_args(), + Ty::from_closure_kind(tcx, goal_kind), + tcx.coroutine_for_closure(def_id), + tupled_upvars_ty, + ) + }; + + Ok(( + args.coroutine_closure_sig().rebind(( + sig.tupled_inputs_ty, + sig.return_ty, + coroutine_ty, + )), + nested, + )) + } + + ty::FnDef(..) | ty::FnPtr(..) => { + let bound_sig = self_ty.fn_sig(tcx); + let sig = bound_sig.skip_binder(); + let future_trait_def_id = tcx.require_lang_item(LangItem::Future, None); + // `FnDef` and `FnPtr` only implement `AsyncFn*` when their + // return type implements `Future`. + let nested = vec![ + bound_sig + .rebind(ty::TraitRef::new(tcx, future_trait_def_id, [sig.output()])) + .to_predicate(tcx), + ]; + let future_output_def_id = tcx + .associated_items(future_trait_def_id) + .filter_by_name_unhygienic(sym::Output) + .next() + .unwrap() + .def_id; + let future_output_ty = Ty::new_projection(tcx, future_output_def_id, [sig.output()]); + Ok(( + bound_sig.rebind((Ty::new_tup(tcx, sig.inputs()), sig.output(), future_output_ty)), + nested, + )) } + ty::Closure(_, args) => { + let args = args.as_closure(); + let bound_sig = args.sig(); + let sig = bound_sig.skip_binder(); + let future_trait_def_id = tcx.require_lang_item(LangItem::Future, None); + // `Closure`s only implement `AsyncFn*` when their return type + // implements `Future`. + let mut nested = vec![ + bound_sig + .rebind(ty::TraitRef::new(tcx, future_trait_def_id, [sig.output()])) + .to_predicate(tcx), + ]; + + // Additionally, we need to check that the closure kind + // is still compatible. + let kind_ty = args.kind_ty(); + if let Some(closure_kind) = kind_ty.to_opt_closure_kind() { + if !closure_kind.extends(goal_kind) { + return Err(NoSolution); + } + } else { + let async_fn_kind_trait_def_id = + tcx.require_lang_item(LangItem::AsyncFnKindHelper, None); + // When we don't know the closure kind (and therefore also the closure's upvars, + // which are computed at the same time), we must delay the computation of the + // generator's upvars. We do this using the `AsyncFnKindHelper`, which as a trait + // goal functions similarly to the old `ClosureKind` predicate, and ensures that + // the goal kind <= the closure kind. As a projection `AsyncFnKindHelper::Upvars` + // will project to the right upvars for the generator, appending the inputs and + // coroutine upvars respecting the closure kind. + nested.push( + ty::TraitRef::new( + tcx, + async_fn_kind_trait_def_id, + [kind_ty, Ty::from_closure_kind(tcx, goal_kind)], + ) + .to_predicate(tcx), + ); + } - ty::FnDef(..) | ty::FnPtr(..) | ty::Closure(..) => Err(NoSolution), + let future_output_def_id = tcx + .associated_items(future_trait_def_id) + .filter_by_name_unhygienic(sym::Output) + .next() + .unwrap() + .def_id; + let future_output_ty = Ty::new_projection(tcx, future_output_def_id, [sig.output()]); + Ok((bound_sig.rebind((sig.inputs()[0], sig.output(), future_output_ty)), nested)) + } ty::Bool | ty::Char 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 76c50a11102..803379af005 100644 --- a/compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs +++ b/compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs @@ -477,10 +477,11 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> { } } } else { - let kind = self.infcx.instantiate_binder_with_placeholders(kind); - let goal = goal.with(self.tcx(), ty::Binder::dummy(kind)); - self.add_goal(GoalSource::Misc, goal); - self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + self.infcx.enter_forall(kind, |kind| { + let goal = goal.with(self.tcx(), ty::Binder::dummy(kind)); + self.add_goal(GoalSource::Misc, goal); + self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + }) } } @@ -801,13 +802,13 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { ) } - pub(super) fn instantiate_binder_with_placeholders<T: TypeFoldable<TyCtxt<'tcx>> + Copy>( + pub(super) fn enter_forall<T: TypeFoldable<TyCtxt<'tcx>> + Copy, U>( &self, value: ty::Binder<'tcx, T>, - ) -> T { - self.infcx.instantiate_binder_with_placeholders(value) + f: impl FnOnce(T) -> U, + ) -> U { + self.infcx.enter_forall(value, f) } - pub(super) fn resolve_vars_if_possible<T>(&self, value: T) -> T where T: TypeFoldable<TyCtxt<'tcx>>, 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 315df06be41..69b69930432 100644 --- a/compiler/rustc_trait_selection/src/solve/eval_ctxt/select.rs +++ b/compiler/rustc_trait_selection/src/solve/eval_ctxt/select.rs @@ -31,103 +31,108 @@ impl<'tcx> InferCtxtSelectExt<'tcx> for InferCtxt<'tcx> { ) -> SelectionResult<'tcx, Selection<'tcx>> { assert!(self.next_trait_solver()); - let trait_goal = Goal::new( - self.tcx, - obligation.param_env, - self.instantiate_binder_with_placeholders(obligation.predicate), - ); - - let (result, _) = EvalCtxt::enter_root(self, GenerateProofTree::Never, |ecx| { - let goal = Goal::new(ecx.tcx(), trait_goal.param_env, trait_goal.predicate); - let (orig_values, canonical_goal) = ecx.canonicalize_goal(goal); - let mut candidates = ecx.compute_canonical_trait_candidates(canonical_goal); - - // pseudo-winnow - if candidates.len() == 0 { - return Err(SelectionError::Unimplemented); - } else if candidates.len() > 1 { - let mut i = 0; - while i < candidates.len() { - let should_drop_i = (0..candidates.len()).filter(|&j| i != j).any(|j| { - candidate_should_be_dropped_in_favor_of( - ecx.tcx(), - &candidates[i], - &candidates[j], - ) - }); - if should_drop_i { - candidates.swap_remove(i); - } else { - i += 1; - if i > 1 { - return Ok(None); + self.enter_forall(obligation.predicate, |pred| { + let trait_goal = Goal::new(self.tcx, obligation.param_env, pred); + + let (result, _) = EvalCtxt::enter_root(self, GenerateProofTree::Never, |ecx| { + let goal = Goal::new(ecx.tcx(), trait_goal.param_env, trait_goal.predicate); + let (orig_values, canonical_goal) = ecx.canonicalize_goal(goal); + let mut candidates = ecx.compute_canonical_trait_candidates(canonical_goal); + + // pseudo-winnow + if candidates.len() == 0 { + return Err(SelectionError::Unimplemented); + } else if candidates.len() > 1 { + let mut i = 0; + while i < candidates.len() { + let should_drop_i = (0..candidates.len()).filter(|&j| i != j).any(|j| { + candidate_should_be_dropped_in_favor_of( + ecx.tcx(), + &candidates[i], + &candidates[j], + ) + }); + if should_drop_i { + candidates.swap_remove(i); + } else { + i += 1; + if i > 1 { + return Ok(None); + } } } } - } - let candidate = candidates.pop().unwrap(); - let (certainty, nested_goals) = ecx - .instantiate_and_apply_query_response( - trait_goal.param_env, - orig_values, - candidate.result, - ) - .map_err(|_| SelectionError::Unimplemented)?; - - Ok(Some((candidate, certainty, nested_goals))) - }); - - let (candidate, certainty, nested_goals) = match result { - Ok(Some((candidate, certainty, nested_goals))) => (candidate, certainty, nested_goals), - Ok(None) => return Ok(None), - Err(e) => return Err(e), - }; - - let nested_obligations: Vec<_> = nested_goals - .into_iter() - .map(|goal| { - Obligation::new(self.tcx, ObligationCause::dummy(), goal.param_env, goal.predicate) - }) - .collect(); - - let goal = self.resolve_vars_if_possible(trait_goal); - match (certainty, candidate.source) { - // Rematching the implementation will instantiate the same nested goals that - // would have caused the ambiguity, so we can still make progress here regardless. - (_, CandidateSource::Impl(def_id)) => { - rematch_impl(self, goal, def_id, nested_obligations) - } + let candidate = candidates.pop().unwrap(); + let (certainty, nested_goals) = ecx + .instantiate_and_apply_query_response( + trait_goal.param_env, + orig_values, + candidate.result, + ) + .map_err(|_| SelectionError::Unimplemented)?; + + Ok(Some((candidate, certainty, nested_goals))) + }); + + let (candidate, certainty, nested_goals) = match result { + Ok(Some((candidate, certainty, nested_goals))) => { + (candidate, certainty, nested_goals) + } + Ok(None) => return Ok(None), + Err(e) => return Err(e), + }; + + let nested_obligations: Vec<_> = nested_goals + .into_iter() + .map(|goal| { + Obligation::new( + self.tcx, + ObligationCause::dummy(), + goal.param_env, + goal.predicate, + ) + }) + .collect(); + + let goal = self.resolve_vars_if_possible(trait_goal); + match (certainty, candidate.source) { + // Rematching the implementation will instantiate the same nested goals that + // would have caused the ambiguity, so we can still make progress here regardless. + (_, CandidateSource::Impl(def_id)) => { + rematch_impl(self, goal, def_id, nested_obligations) + } - // If an unsize goal is ambiguous, then we can manually rematch it to make - // selection progress for coercion during HIR typeck. If it is *not* ambiguous, - // but is `BuiltinImplSource::Misc`, it may have nested `Unsize` goals, - // and we need to rematch those to detect tuple unsizing and trait upcasting. - // FIXME: This will be wrong if we have param-env or where-clause bounds - // with the unsize goal -- we may need to mark those with different impl - // sources. - (Certainty::Maybe(_), CandidateSource::BuiltinImpl(src)) - | (Certainty::Yes, CandidateSource::BuiltinImpl(src @ BuiltinImplSource::Misc)) - if self.tcx.lang_items().unsize_trait() == Some(goal.predicate.def_id()) => - { - rematch_unsize(self, goal, nested_obligations, src, certainty) - } + // If an unsize goal is ambiguous, then we can manually rematch it to make + // selection progress for coercion during HIR typeck. If it is *not* ambiguous, + // but is `BuiltinImplSource::Misc`, it may have nested `Unsize` goals, + // and we need to rematch those to detect tuple unsizing and trait upcasting. + // FIXME: This will be wrong if we have param-env or where-clause bounds + // with the unsize goal -- we may need to mark those with different impl + // sources. + (Certainty::Maybe(_), CandidateSource::BuiltinImpl(src)) + | (Certainty::Yes, CandidateSource::BuiltinImpl(src @ BuiltinImplSource::Misc)) + if self.tcx.lang_items().unsize_trait() == Some(goal.predicate.def_id()) => + { + rematch_unsize(self, goal, nested_obligations, src, certainty) + } - // Technically some builtin impls have nested obligations, but if - // `Certainty::Yes`, then they should've all been verified and don't - // need re-checking. - (Certainty::Yes, CandidateSource::BuiltinImpl(src)) => { - Ok(Some(ImplSource::Builtin(src, nested_obligations))) - } + // Technically some builtin impls have nested obligations, but if + // `Certainty::Yes`, then they should've all been verified and don't + // need re-checking. + (Certainty::Yes, CandidateSource::BuiltinImpl(src)) => { + Ok(Some(ImplSource::Builtin(src, nested_obligations))) + } - // It's fine not to do anything to rematch these, since there are no - // nested obligations. - (Certainty::Yes, CandidateSource::ParamEnv(_) | CandidateSource::AliasBound) => { - Ok(Some(ImplSource::Param(nested_obligations))) - } + // It's fine not to do anything to rematch these, since there are no + // nested obligations. + (Certainty::Yes, CandidateSource::ParamEnv(_) | CandidateSource::AliasBound) => { + Ok(Some(ImplSource::Param(nested_obligations))) + } - (Certainty::Maybe(_), _) => Ok(None), - } + (Certainty::Maybe(_), _) => Ok(None), + } + }) } } diff --git a/compiler/rustc_trait_selection/src/solve/fulfill.rs b/compiler/rustc_trait_selection/src/solve/fulfill.rs index f08622816ec..63555a305d8 100644 --- a/compiler/rustc_trait_selection/src/solve/fulfill.rs +++ b/compiler/rustc_trait_selection/src/solve/fulfill.rs @@ -140,7 +140,7 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentCtxt<'tcx> { ) } ty::PredicateKind::Subtype(pred) => { - let (a, b) = infcx.instantiate_binder_with_placeholders( + let (a, b) = infcx.enter_forall_and_leak_universe( goal.predicate.kind().rebind((pred.a, pred.b)), ); let expected_found = ExpectedFound::new(true, a, b); @@ -150,7 +150,7 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentCtxt<'tcx> { ) } ty::PredicateKind::Coerce(pred) => { - let (a, b) = infcx.instantiate_binder_with_placeholders( + let (a, b) = infcx.enter_forall_and_leak_universe( goal.predicate.kind().rebind((pred.a, pred.b)), ); let expected_found = ExpectedFound::new(false, a, b); diff --git a/compiler/rustc_trait_selection/src/solve/mod.rs b/compiler/rustc_trait_selection/src/solve/mod.rs index 6984f0ba694..a7330136fe7 100644 --- a/compiler/rustc_trait_selection/src/solve/mod.rs +++ b/compiler/rustc_trait_selection/src/solve/mod.rs @@ -124,25 +124,6 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> { } } - #[instrument(level = "debug", skip(self))] - fn compute_closure_kind_goal( - &mut self, - goal: Goal<'tcx, (DefId, ty::GenericArgsRef<'tcx>, ty::ClosureKind)>, - ) -> QueryResult<'tcx> { - let (_, args, expected_kind) = goal.predicate; - let found_kind = args.as_closure().kind_ty().to_opt_closure_kind(); - - let Some(found_kind) = found_kind else { - return self.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS); - }; - if found_kind.extends(expected_kind) { - self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) - } else { - Err(NoSolution) - } - } - - #[instrument(level = "debug", skip(self))] fn compute_object_safe_goal(&mut self, trait_def_id: DefId) -> QueryResult<'tcx> { if self.tcx().check_is_object_safe(trait_def_id) { self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) 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 47ba549022d..d177109c420 100644 --- a/compiler/rustc_trait_selection/src/solve/normalizes_to/mod.rs +++ b/compiler/rustc_trait_selection/src/solve/normalizes_to/mod.rs @@ -491,6 +491,8 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> { goal: Goal<'tcx, Self>, ) -> QueryResult<'tcx> { 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| { let metadata_ty = match goal.predicate.self_ty().kind() { ty::Bool @@ -522,7 +524,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> { } ty::Alias(_, _) | ty::Param(_) | ty::Placeholder(..) => { - // FIXME(ptr_metadata): It would also be possible to return a `Ok(Ambig)` with no constraints. + // This is the "fallback impl" for type parameters, unnormalizable projections + // and opaque types: If the `self_ty` is `Sized`, then the metadata is `()`. + // FIXME(ptr_metadata): This impl overlaps with the other impls and shouldn't + // exist. Instead, `Pointee<Metadata = ()>` should be a supertrait of `Sized`. let sized_predicate = ty::TraitRef::from_lang_item( tcx, LangItem::Sized, @@ -536,30 +541,16 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> { ty::Adt(def, args) if def.is_struct() => match def.non_enum_variant().tail_opt() { None => tcx.types.unit, - Some(field_def) => { - let self_ty = field_def.ty(tcx, args); - // FIXME(-Znext-solver=coinductive): Should this be `GoalSource::ImplWhereBound`? - ecx.add_goal( - GoalSource::Misc, - goal.with(tcx, goal.predicate.with_self_ty(tcx, self_ty)), - ); - return ecx - .evaluate_added_goals_and_make_canonical_response(Certainty::Yes); + Some(tail_def) => { + let tail_ty = tail_def.ty(tcx, args); + Ty::new_projection(tcx, metadata_def_id, [tail_ty]) } }, ty::Adt(_, _) => tcx.types.unit, ty::Tuple(elements) => match elements.last() { None => tcx.types.unit, - Some(&self_ty) => { - // FIXME(-Znext-solver=coinductive): Should this be `GoalSource::ImplWhereBound`? - ecx.add_goal( - GoalSource::Misc, - goal.with(tcx, goal.predicate.with_self_ty(tcx, self_ty)), - ); - return ecx - .evaluate_added_goals_and_make_canonical_response(Certainty::Yes); - } + Some(&tail_ty) => Ty::new_projection(tcx, metadata_def_id, [tail_ty]), }, ty::Infer( diff --git a/compiler/rustc_trait_selection/src/solve/trait_goals.rs b/compiler/rustc_trait_selection/src/solve/trait_goals.rs index fd09a6b671d..044832224e5 100644 --- a/compiler/rustc_trait_selection/src/solve/trait_goals.rs +++ b/compiler/rustc_trait_selection/src/solve/trait_goals.rs @@ -1049,14 +1049,21 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { fn probe_and_evaluate_goal_for_constituent_tys( &mut self, goal: Goal<'tcx, TraitPredicate<'tcx>>, - constituent_tys: impl Fn(&EvalCtxt<'_, 'tcx>, Ty<'tcx>) -> Result<Vec<Ty<'tcx>>, NoSolution>, + constituent_tys: impl Fn( + &EvalCtxt<'_, 'tcx>, + Ty<'tcx>, + ) -> Result<Vec<ty::Binder<'tcx, Ty<'tcx>>>, NoSolution>, ) -> QueryResult<'tcx> { self.probe_misc_candidate("constituent tys").enter(|ecx| { ecx.add_goals( GoalSource::ImplWhereBound, constituent_tys(ecx, goal.predicate.self_ty())? .into_iter() - .map(|ty| goal.with(ecx.tcx(), goal.predicate.with_self_ty(ecx.tcx(), ty))) + .map(|ty| { + ecx.enter_forall(ty, |ty| { + goal.with(ecx.tcx(), goal.predicate.with_self_ty(ecx.tcx(), ty)) + }) + }) .collect::<Vec<_>>(), ); ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) diff --git a/compiler/rustc_trait_selection/src/traits/coherence.rs b/compiler/rustc_trait_selection/src/traits/coherence.rs index 4b20de26219..cbe9a238b1c 100644 --- a/compiler/rustc_trait_selection/src/traits/coherence.rs +++ b/compiler/rustc_trait_selection/src/traits/coherence.rs @@ -971,7 +971,7 @@ impl<'a, 'tcx> ProofTreeVisitor<'tcx> for AmbiguityCausesVisitor<'a, 'tcx> { let Goal { param_env, predicate } = goal.goal(); - // For bound predicates we simply call `infcx.instantiate_binder_with_placeholders` + // For bound predicates we simply call `infcx.enter_forall` // and then prove the resulting predicate as a nested goal. let trait_ref = match predicate.kind().no_bound_vars() { Some(ty::PredicateKind::Clause(ty::ClauseKind::Trait(tr))) => tr.trait_ref, 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 b246e476bed..c6f5af08013 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs @@ -21,51 +21,62 @@ pub fn recompute_applicable_impls<'tcx>( let impl_may_apply = |impl_def_id| { let ocx = ObligationCtxt::new(infcx); - let placeholder_obligation = - infcx.instantiate_binder_with_placeholders(obligation.predicate); - let obligation_trait_ref = - ocx.normalize(&ObligationCause::dummy(), param_env, placeholder_obligation.trait_ref); - - let impl_args = infcx.fresh_args_for_item(DUMMY_SP, impl_def_id); - let impl_trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap().instantiate(tcx, impl_args); - let impl_trait_ref = ocx.normalize(&ObligationCause::dummy(), param_env, impl_trait_ref); - - if let Err(_) = - ocx.eq(&ObligationCause::dummy(), param_env, obligation_trait_ref, impl_trait_ref) - { - return false; - } + infcx.enter_forall(obligation.predicate, |placeholder_obligation| { + let obligation_trait_ref = ocx.normalize( + &ObligationCause::dummy(), + param_env, + placeholder_obligation.trait_ref, + ); + + let impl_args = infcx.fresh_args_for_item(DUMMY_SP, impl_def_id); + let impl_trait_ref = + tcx.impl_trait_ref(impl_def_id).unwrap().instantiate(tcx, impl_args); + let impl_trait_ref = + ocx.normalize(&ObligationCause::dummy(), param_env, impl_trait_ref); + + if let Err(_) = + ocx.eq(&ObligationCause::dummy(), param_env, obligation_trait_ref, impl_trait_ref) + { + return false; + } - let impl_predicates = tcx.predicates_of(impl_def_id).instantiate(tcx, impl_args); - ocx.register_obligations(impl_predicates.predicates.iter().map(|&predicate| { - Obligation::new(tcx, ObligationCause::dummy(), param_env, predicate) - })); + let impl_predicates = tcx.predicates_of(impl_def_id).instantiate(tcx, impl_args); + ocx.register_obligations(impl_predicates.predicates.iter().map(|&predicate| { + Obligation::new(tcx, ObligationCause::dummy(), param_env, predicate) + })); - ocx.select_where_possible().is_empty() + ocx.select_where_possible().is_empty() + }) }; let param_env_candidate_may_apply = |poly_trait_predicate: ty::PolyTraitPredicate<'tcx>| { let ocx = ObligationCtxt::new(infcx); - let placeholder_obligation = - infcx.instantiate_binder_with_placeholders(obligation.predicate); - let obligation_trait_ref = - ocx.normalize(&ObligationCause::dummy(), param_env, placeholder_obligation.trait_ref); - - let param_env_predicate = infcx.instantiate_binder_with_fresh_vars( - DUMMY_SP, - BoundRegionConversionTime::HigherRankedType, - poly_trait_predicate, - ); - let param_env_trait_ref = - ocx.normalize(&ObligationCause::dummy(), param_env, param_env_predicate.trait_ref); - - if let Err(_) = - ocx.eq(&ObligationCause::dummy(), param_env, obligation_trait_ref, param_env_trait_ref) - { - return false; - } + infcx.enter_forall(obligation.predicate, |placeholder_obligation| { + let obligation_trait_ref = ocx.normalize( + &ObligationCause::dummy(), + param_env, + placeholder_obligation.trait_ref, + ); + + let param_env_predicate = infcx.instantiate_binder_with_fresh_vars( + DUMMY_SP, + BoundRegionConversionTime::HigherRankedType, + poly_trait_predicate, + ); + let param_env_trait_ref = + ocx.normalize(&ObligationCause::dummy(), param_env, param_env_predicate.trait_ref); + + if let Err(_) = ocx.eq( + &ObligationCause::dummy(), + param_env, + obligation_trait_ref, + param_env_trait_ref, + ) { + return false; + } - ocx.select_where_possible().is_empty() + ocx.select_where_possible().is_empty() + }) }; let mut ambiguities = Vec::new(); 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 972da180a33..ceff7187646 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 @@ -64,39 +64,44 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { ) -> Option<(DefId, GenericArgsRef<'tcx>)> { let tcx = self.tcx; let param_env = obligation.param_env; - let trait_ref = self.instantiate_binder_with_placeholders(trait_ref); - let trait_self_ty = trait_ref.self_ty(); + self.enter_forall(trait_ref, |trait_ref| { + let trait_self_ty = trait_ref.self_ty(); - let mut self_match_impls = vec![]; - let mut fuzzy_match_impls = vec![]; + let mut self_match_impls = vec![]; + let mut fuzzy_match_impls = vec![]; - self.tcx.for_each_relevant_impl(trait_ref.def_id, trait_self_ty, |def_id| { - let impl_args = self.fresh_args_for_item(obligation.cause.span, def_id); - let impl_trait_ref = tcx.impl_trait_ref(def_id).unwrap().instantiate(tcx, impl_args); + self.tcx.for_each_relevant_impl(trait_ref.def_id, trait_self_ty, |def_id| { + let impl_args = self.fresh_args_for_item(obligation.cause.span, def_id); + let impl_trait_ref = + tcx.impl_trait_ref(def_id).unwrap().instantiate(tcx, impl_args); - let impl_self_ty = impl_trait_ref.self_ty(); + let impl_self_ty = impl_trait_ref.self_ty(); - if self.can_eq(param_env, trait_self_ty, impl_self_ty) { - self_match_impls.push((def_id, impl_args)); + if self.can_eq(param_env, trait_self_ty, impl_self_ty) { + self_match_impls.push((def_id, impl_args)); - if iter::zip(trait_ref.args.types().skip(1), impl_trait_ref.args.types().skip(1)) + if iter::zip( + trait_ref.args.types().skip(1), + impl_trait_ref.args.types().skip(1), + ) .all(|(u, v)| self.fuzzy_match_tys(u, v, false).is_some()) - { - fuzzy_match_impls.push((def_id, impl_args)); + { + fuzzy_match_impls.push((def_id, impl_args)); + } } - } - }); + }); - let impl_def_id_and_args = if self_match_impls.len() == 1 { - self_match_impls[0] - } else if fuzzy_match_impls.len() == 1 { - fuzzy_match_impls[0] - } else { - return None; - }; + let impl_def_id_and_args = if self_match_impls.len() == 1 { + self_match_impls[0] + } else if fuzzy_match_impls.len() == 1 { + fuzzy_match_impls[0] + } else { + return None; + }; - tcx.has_attr(impl_def_id_and_args.0, sym::rustc_on_unimplemented) - .then_some(impl_def_id_and_args) + tcx.has_attr(impl_def_id_and_args.0, sym::rustc_on_unimplemented) + .then_some(impl_def_id_and_args) + }) } /// Used to set on_unimplemented's `ItemContext` 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 243f583aed8..f68200b6f4d 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs @@ -19,7 +19,7 @@ use rustc_errors::{ use rustc_hir as hir; use rustc_hir::def::{DefKind, Res}; use rustc_hir::def_id::DefId; -use rustc_hir::intravisit::{Map, Visitor}; +use rustc_hir::intravisit::Visitor; use rustc_hir::is_range_literal; use rustc_hir::lang_items::LangItem; use rustc_hir::{CoroutineDesugaring, CoroutineKind, CoroutineSource, Expr, HirId, Node}; @@ -774,7 +774,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { if steps > 0 { // Don't care about `&mut` because `DerefMut` is used less // often and user will not expect that an autoderef happens. - if let Some(hir::Node::Expr(hir::Expr { + if let hir::Node::Expr(hir::Expr { kind: hir::ExprKind::AddrOf( hir::BorrowKind::Ref, @@ -782,7 +782,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { expr, ), .. - })) = self.tcx.opt_hir_node(*arg_hir_id) + }) = self.tcx.hir_node(*arg_hir_id) { let derefs = "*".repeat(steps); err.span_suggestion_verbose( @@ -1199,7 +1199,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { let Res::Local(hir_id) = path.res else { return; }; - let Some(hir::Node::Pat(pat)) = self.tcx.opt_hir_node(hir_id) else { + let hir::Node::Pat(pat) = self.tcx.hir_node(hir_id) else { return; }; let Some(hir::Node::Local(hir::Local { ty: None, init: Some(init), .. })) = @@ -1248,52 +1248,55 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { trait_pred: ty::PolyTraitPredicate<'tcx>, ) -> bool { let self_ty = self.resolve_vars_if_possible(trait_pred.self_ty()); - let ty = self.instantiate_binder_with_placeholders(self_ty); - let Some(generics) = self.tcx.hir().get_generics(obligation.cause.body_id) else { - return false; - }; - let ty::Ref(_, inner_ty, hir::Mutability::Not) = ty.kind() else { return false }; - let ty::Param(param) = inner_ty.kind() else { return false }; - let ObligationCauseCode::FunctionArgumentObligation { arg_hir_id, .. } = - obligation.cause.code() - else { - return false; - }; - let arg_node = self.tcx.hir_node(*arg_hir_id); - let Node::Expr(Expr { kind: hir::ExprKind::Path(_), .. }) = arg_node else { return false }; + self.enter_forall(self_ty, |ty: Ty<'_>| { + let Some(generics) = self.tcx.hir().get_generics(obligation.cause.body_id) else { + return false; + }; + let ty::Ref(_, inner_ty, hir::Mutability::Not) = ty.kind() else { return false }; + let ty::Param(param) = inner_ty.kind() else { return false }; + let ObligationCauseCode::FunctionArgumentObligation { arg_hir_id, .. } = + obligation.cause.code() + else { + return false; + }; + let arg_node = self.tcx.hir_node(*arg_hir_id); + let Node::Expr(Expr { kind: hir::ExprKind::Path(_), .. }) = arg_node else { + return false; + }; - let clone_trait = self.tcx.require_lang_item(LangItem::Clone, None); - let has_clone = |ty| { - self.type_implements_trait(clone_trait, [ty], obligation.param_env) - .must_apply_modulo_regions() - }; + let clone_trait = self.tcx.require_lang_item(LangItem::Clone, None); + let has_clone = |ty| { + self.type_implements_trait(clone_trait, [ty], obligation.param_env) + .must_apply_modulo_regions() + }; - let new_obligation = self.mk_trait_obligation_with_new_self_ty( - obligation.param_env, - trait_pred.map_bound(|trait_pred| (trait_pred, *inner_ty)), - ); + let new_obligation = self.mk_trait_obligation_with_new_self_ty( + obligation.param_env, + trait_pred.map_bound(|trait_pred| (trait_pred, *inner_ty)), + ); - if self.predicate_may_hold(&new_obligation) && has_clone(ty) { - if !has_clone(param.to_ty(self.tcx)) { - suggest_constraining_type_param( - self.tcx, - generics, - err, - param.name.as_str(), - "Clone", - Some(clone_trait), - None, + if self.predicate_may_hold(&new_obligation) && has_clone(ty) { + if !has_clone(param.to_ty(self.tcx)) { + suggest_constraining_type_param( + self.tcx, + generics, + err, + param.name.as_str(), + "Clone", + Some(clone_trait), + None, + ); + } + err.span_suggestion_verbose( + obligation.cause.span.shrink_to_hi(), + "consider using clone here", + ".clone()".to_string(), + Applicability::MaybeIncorrect, ); + return true; } - err.span_suggestion_verbose( - obligation.cause.span.shrink_to_hi(), - "consider using clone here", - ".clone()", - Applicability::MaybeIncorrect, - ); - return true; - } - false + false + }) } /// Extracts information about a callable type for diagnostics. This is a @@ -1786,7 +1789,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { } if let hir::ExprKind::Path(hir::QPath::Resolved(None, path)) = expr.kind && let Res::Local(hir_id) = path.res - && let Some(hir::Node::Pat(binding)) = self.tcx.opt_hir_node(hir_id) + && let hir::Node::Pat(binding) = self.tcx.hir_node(hir_id) && let Some(hir::Node::Local(local)) = self.tcx.hir().find_parent(binding.hir_id) && let None = local.ty && let Some(binding_expr) = local.init @@ -2198,7 +2201,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { let ty::FnPtr(found) = found.kind() else { return; }; - let Some(Node::Expr(arg)) = self.tcx.opt_hir_node(*arg_hir_id) else { + let Node::Expr(arg) = self.tcx.hir_node(*arg_hir_id) else { return; }; let hir::ExprKind::Path(path) = arg.kind else { @@ -3186,8 +3189,8 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { } ObligationCauseCode::VariableType(hir_id) => { let parent_node = tcx.hir().parent_id(hir_id); - match tcx.opt_hir_node(parent_node) { - Some(Node::Local(hir::Local { ty: Some(ty), .. })) => { + match tcx.hir_node(parent_node) { + Node::Local(hir::Local { ty: Some(ty), .. }) => { err.span_suggestion_verbose( ty.span.shrink_to_lo(), "consider borrowing here", @@ -3196,10 +3199,10 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { ); err.note("all local variables must have a statically known size"); } - Some(Node::Local(hir::Local { + Node::Local(hir::Local { init: Some(hir::Expr { kind: hir::ExprKind::Index(..), span, .. }), .. - })) => { + }) => { // When encountering an assignment of an unsized trait, like // `let x = ""[..];`, provide a suggestion to borrow the initializer in // order to use have a slice instead. @@ -3211,7 +3214,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { ); err.note("all local variables must have a statically known size"); } - Some(Node::Param(param)) => { + Node::Param(param) => { err.span_suggestion_verbose( param.ty_span.shrink_to_lo(), "function arguments must have a statically known size, borrowed types \ @@ -3233,7 +3236,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { let borrowed_msg = "function arguments must have a statically known size, borrowed \ types always have a known size"; if let Some(hir_id) = hir_id - && let Some(hir::Node::Param(param)) = self.tcx.hir().find(hir_id) + && let hir::Node::Param(param) = self.tcx.hir_node(hir_id) && let Some(item) = self.tcx.hir().find_parent(hir_id) && let Some(decl) = item.fn_decl() && let Some(t) = decl.inputs.iter().find(|t| param.ty_span.contains(t.span)) @@ -3247,7 +3250,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { // param._ty_span ty = Some(t); } else if let Some(hir_id) = hir_id - && let Some(hir::Node::Ty(t)) = self.tcx.hir().find(hir_id) + && let hir::Node::Ty(t) = self.tcx.hir_node(hir_id) { ty = Some(t); } @@ -3958,7 +3961,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { call_hir_id: HirId, ) { let tcx = self.tcx; - if let Some(Node::Expr(expr)) = tcx.opt_hir_node(arg_hir_id) + if let Node::Expr(expr) = tcx.hir_node(arg_hir_id) && let Some(typeck_results) = &self.typeck_results { if let hir::Expr { kind: hir::ExprKind::Block(block, _), .. } = expr { @@ -4038,26 +4041,27 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { if let Some(where_pred) = where_pred.as_trait_clause() && let Some(failed_pred) = failed_pred.to_opt_poly_trait_pred() { - let where_pred = self.instantiate_binder_with_placeholders(where_pred); - let failed_pred = self.instantiate_binder_with_fresh_vars( - expr.span, - BoundRegionConversionTime::FnCall, - failed_pred, - ); + self.enter_forall(where_pred, |where_pred| { + let failed_pred = self.instantiate_binder_with_fresh_vars( + expr.span, + BoundRegionConversionTime::FnCall, + failed_pred, + ); - let zipped = iter::zip(where_pred.trait_ref.args, failed_pred.trait_ref.args); - 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), - } - }) - } + let zipped = + iter::zip(where_pred.trait_ref.args, failed_pred.trait_ref.args); + 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), + } + }) + } + }) } else if let Some(where_pred) = where_pred.as_projection_clause() && let Some(failed_pred) = failed_pred.to_opt_poly_projection_pred() && let Some(found) = failed_pred.skip_binder().term.ty() @@ -4074,9 +4078,9 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { } if let hir::ExprKind::Path(hir::QPath::Resolved(None, path)) = expr.kind && let hir::Path { res: Res::Local(hir_id), .. } = path - && let Some(hir::Node::Pat(binding)) = self.tcx.opt_hir_node(*hir_id) + && let hir::Node::Pat(binding) = self.tcx.hir_node(*hir_id) && let parent_hir_id = self.tcx.hir().parent_id(binding.hir_id) - && let Some(hir::Node::Local(local)) = self.tcx.opt_hir_node(parent_hir_id) + && let hir::Node::Local(local) = self.tcx.hir_node(parent_hir_id) && let Some(binding_expr) = local.init { // If the expression we're calling on is a binding, we want to point at the @@ -4087,17 +4091,16 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { self.point_at_chain(expr, typeck_results, type_diffs, param_env, err); } } - let call_node = tcx.opt_hir_node(call_hir_id); - if let Some(Node::Expr(hir::Expr { - kind: hir::ExprKind::MethodCall(path, rcvr, ..), .. - })) = call_node + let call_node = tcx.hir_node(call_hir_id); + if let Node::Expr(hir::Expr { kind: hir::ExprKind::MethodCall(path, rcvr, ..), .. }) = + call_node { if Some(rcvr.span) == err.span.primary_span() { err.replace_span_with(path.ident.span, true); } } - if let Some(Node::Expr(expr)) = tcx.opt_hir_node(call_hir_id) { + if let Node::Expr(expr) = tcx.hir_node(call_hir_id) { if let hir::ExprKind::Call(hir::Expr { span, .. }, _) | hir::ExprKind::MethodCall( hir::PathSegment { ident: Ident { span, .. }, .. }, @@ -4334,7 +4337,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { if let hir::ExprKind::Path(hir::QPath::Resolved(None, path)) = expr.kind && let hir::Path { res: Res::Local(hir_id), .. } = path - && let Some(hir::Node::Pat(binding)) = self.tcx.opt_hir_node(*hir_id) + && let hir::Node::Pat(binding) = self.tcx.hir_node(*hir_id) && let Some(parent) = self.tcx.hir().find_parent(binding.hir_id) { // We've reached the root of the method call chain... @@ -4615,14 +4618,15 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { { self.probe(|_| { let ocx = ObligationCtxt::new(self); - let pred = self.instantiate_binder_with_placeholders(pred); - let pred = ocx.normalize(&ObligationCause::dummy(), param_env, pred); - ocx.register_obligation(Obligation::new( - self.tcx, - ObligationCause::dummy(), - param_env, - pred, - )); + self.enter_forall(pred, |pred| { + let pred = ocx.normalize(&ObligationCause::dummy(), param_env, pred); + ocx.register_obligation(Obligation::new( + self.tcx, + ObligationCause::dummy(), + param_env, + pred, + )); + }); if !ocx.select_where_possible().is_empty() { // encountered errors. return; @@ -4769,13 +4773,13 @@ fn hint_missing_borrow<'tcx>( } let found_args = match found.kind() { - ty::FnPtr(f) => infcx.instantiate_binder_with_placeholders(*f).inputs().iter(), + ty::FnPtr(f) => infcx.enter_forall(*f, |f| f.inputs().iter()), kind => { span_bug!(span, "found was converted to a FnPtr above but is now {:?}", kind) } }; let expected_args = match expected.kind() { - ty::FnPtr(f) => infcx.instantiate_binder_with_placeholders(*f).inputs().iter(), + ty::FnPtr(f) => infcx.enter_forall(*f, |f| f.inputs().iter()), kind => { span_bug!(span, "expected was converted to a FnPtr above but is now {:?}", kind) } diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs index 1ac0f172ef4..07e4fef9dd4 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs @@ -993,13 +993,13 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { ) -> Result<(), ErrorGuaranteed> { if let ObligationCauseCode::FunctionArgumentObligation { arg_hir_id, .. } = obligation.cause.code() - && let Some(Node::Expr(arg)) = self.tcx.opt_hir_node(*arg_hir_id) + && let Node::Expr(arg) = self.tcx.hir_node(*arg_hir_id) && let arg = arg.peel_borrows() && let hir::ExprKind::Path(hir::QPath::Resolved( None, hir::Path { res: hir::def::Res::Local(hir_id), .. }, )) = arg.kind - && let Some(Node::Pat(pat)) = self.tcx.opt_hir_node(*hir_id) + && let Node::Pat(pat) = self.tcx.hir_node(*hir_id) && let Some((preds, guar)) = self.reported_trait_errors.borrow().get(&pat.span) && preds.contains(&obligation.predicate) { @@ -1037,10 +1037,8 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { } } let hir_id = self.tcx.local_def_id_to_hir_id(obligation.cause.body_id); - let body_id = match self.tcx.opt_hir_node(hir_id) { - Some(hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn(_, _, body_id), .. })) => { - body_id - } + let body_id = match self.tcx.hir_node(hir_id) { + hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn(_, _, body_id), .. }) => body_id, _ => return false, }; let mut v = V { search_span: span, found: None }; @@ -1163,7 +1161,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { if let hir::ExprKind::Path(hir::QPath::Resolved(None, path)) = expr.kind && let hir::Path { res: hir::def::Res::Local(hir_id), .. } = path - && let Some(hir::Node::Pat(binding)) = self.tcx.opt_hir_node(*hir_id) + && let hir::Node::Pat(binding) = self.tcx.hir_node(*hir_id) && let Some(parent) = self.tcx.hir().find_parent(binding.hir_id) { // We've reached the root of the method call chain... @@ -1307,12 +1305,13 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { let mut pred = obligation.predicate.to_opt_poly_trait_pred(); while let Some((next_code, next_pred)) = code.parent() { if let Some(pred) = pred { - let pred = self.instantiate_binder_with_placeholders(pred); - diag.note(format!( - "`{}` must implement `{}`, but it does not", - pred.self_ty(), - pred.print_modifiers_and_trait_path() - )); + self.enter_forall(pred, |pred| { + diag.note(format!( + "`{}` must implement `{}`, but it does not", + pred.self_ty(), + pred.print_modifiers_and_trait_path() + )); + }) } code = next_code; pred = next_pred; @@ -2017,70 +2016,78 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { if let [single] = &impl_candidates { if self.probe(|_| { let ocx = ObligationCtxt::new(self); - let obligation_trait_ref = self.instantiate_binder_with_placeholders(trait_ref); - let impl_args = self.fresh_args_for_item(DUMMY_SP, single.impl_def_id); - let impl_trait_ref = ocx.normalize( - &ObligationCause::dummy(), - param_env, - ty::EarlyBinder::bind(single.trait_ref).instantiate(self.tcx, impl_args), - ); - ocx.register_obligations( - self.tcx - .predicates_of(single.impl_def_id) - .instantiate(self.tcx, impl_args) - .into_iter() - .map(|(clause, _)| { - Obligation::new(self.tcx, ObligationCause::dummy(), param_env, clause) - }), - ); - if !ocx.select_where_possible().is_empty() { - return false; - } + self.enter_forall(trait_ref, |obligation_trait_ref| { + let impl_args = self.fresh_args_for_item(DUMMY_SP, single.impl_def_id); + let impl_trait_ref = ocx.normalize( + &ObligationCause::dummy(), + param_env, + ty::EarlyBinder::bind(single.trait_ref).instantiate(self.tcx, impl_args), + ); - let mut terrs = vec![]; - for (obligation_arg, impl_arg) in - std::iter::zip(obligation_trait_ref.args, impl_trait_ref.args) - { - if let Err(terr) = - ocx.eq(&ObligationCause::dummy(), param_env, impl_arg, obligation_arg) - { - terrs.push(terr); - } + ocx.register_obligations( + self.tcx + .predicates_of(single.impl_def_id) + .instantiate(self.tcx, impl_args) + .into_iter() + .map(|(clause, _)| { + Obligation::new( + self.tcx, + ObligationCause::dummy(), + param_env, + clause, + ) + }), + ); if !ocx.select_where_possible().is_empty() { return false; } - } - // Literally nothing unified, just give up. - if terrs.len() == impl_trait_ref.args.len() { - return false; - } + let mut terrs = vec![]; + for (obligation_arg, impl_arg) in + std::iter::zip(obligation_trait_ref.args, impl_trait_ref.args) + { + if let Err(terr) = + ocx.eq(&ObligationCause::dummy(), param_env, impl_arg, obligation_arg) + { + terrs.push(terr); + } + if !ocx.select_where_possible().is_empty() { + return false; + } + } - let cand = - self.resolve_vars_if_possible(impl_trait_ref).fold_with(&mut BottomUpFolder { - tcx: self.tcx, - ty_op: |ty| ty, - lt_op: |lt| lt, - ct_op: |ct| ct.normalize(self.tcx, ty::ParamEnv::empty()), - }); - err.highlighted_help(vec![ - StringPart::normal(format!("the trait `{}` ", cand.print_trait_sugared())), - StringPart::highlighted("is"), - StringPart::normal(" implemented for `"), - StringPart::highlighted(cand.self_ty().to_string()), - StringPart::normal("`"), - ]); + // Literally nothing unified, just give up. + if terrs.len() == impl_trait_ref.args.len() { + return false; + } - if let [TypeError::Sorts(exp_found)] = &terrs[..] { - let exp_found = self.resolve_vars_if_possible(*exp_found); - err.help(format!( - "for that trait implementation, expected `{}`, found `{}`", - exp_found.expected, exp_found.found - )); - } + let cand = self.resolve_vars_if_possible(impl_trait_ref).fold_with( + &mut BottomUpFolder { + tcx: self.tcx, + ty_op: |ty| ty, + lt_op: |lt| lt, + ct_op: |ct| ct.normalize(self.tcx, ty::ParamEnv::empty()), + }, + ); + err.highlighted_help(vec![ + StringPart::normal(format!("the trait `{}` ", cand.print_trait_sugared())), + StringPart::highlighted("is"), + StringPart::normal(" implemented for `"), + StringPart::highlighted(cand.self_ty().to_string()), + StringPart::normal("`"), + ]); + + if let [TypeError::Sorts(exp_found)] = &terrs[..] { + let exp_found = self.resolve_vars_if_possible(*exp_found); + err.help(format!( + "for that trait implementation, expected `{}`, found `{}`", + exp_found.expected, exp_found.found + )); + } - true + true + }) }) { return true; } @@ -2371,6 +2378,12 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { return e; } + if let Err(guar) = self.tcx.ensure().coherent_trait(trait_ref.def_id()) { + // Avoid bogus "type annotations needed `Foo: Bar`" errors on `impl Bar for Foo` in case + // other `Foo` impls are incoherent. + return guar; + } + // This is kind of a hack: it frequently happens that some earlier // error prevents types from being fully inferred, and then we get // a bunch of uninteresting errors saying something like "<generic @@ -2666,6 +2679,14 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { if let Some(e) = self.tainted_by_errors() { return e; } + + if let Err(guar) = + self.tcx.ensure().coherent_trait(self.tcx.parent(data.projection_ty.def_id)) + { + // Avoid bogus "type annotations needed `Foo: Bar`" errors on `impl Bar for Foo` in case + // other `Foo` impls are incoherent. + return guar; + } let subst = data .projection_ty .args diff --git a/compiler/rustc_trait_selection/src/traits/fulfill.rs b/compiler/rustc_trait_selection/src/traits/fulfill.rs index 0337672b302..5ef7a202a12 100644 --- a/compiler/rustc_trait_selection/src/traits/fulfill.rs +++ b/compiler/rustc_trait_selection/src/traits/fulfill.rs @@ -358,8 +358,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { | ty::PredicateKind::Coerce(_) | ty::PredicateKind::Clause(ty::ClauseKind::ConstEvaluatable(..)) | ty::PredicateKind::ConstEquate(..) => { - let pred = - ty::Binder::dummy(infcx.instantiate_binder_with_placeholders(binder)); + let pred = ty::Binder::dummy(infcx.enter_forall_and_leak_universe(binder)); ProcessResult::Changed(mk_pending(vec![obligation.with(infcx.tcx, pred)])) } ty::PredicateKind::Ambiguous => ProcessResult::Unchanged, diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs index 955c81eee6b..054402acb5c 100644 --- a/compiler/rustc_trait_selection/src/traits/project.rs +++ b/compiler/rustc_trait_selection/src/traits/project.rs @@ -40,6 +40,7 @@ use rustc_middle::ty::{self, Term, ToPredicate, Ty, TyCtxt}; use rustc_span::symbol::sym; use std::collections::BTreeMap; +use std::ops::ControlFlow; pub use rustc_middle::traits::Reveal; @@ -250,8 +251,7 @@ pub(super) fn poly_project_and_unify_type<'cx, 'tcx>( let infcx = selcx.infcx; let r = infcx.commit_if_ok(|_snapshot| { let old_universe = infcx.universe(); - let placeholder_predicate = - infcx.instantiate_binder_with_placeholders(obligation.predicate); + let placeholder_predicate = infcx.enter_forall_and_leak_universe(obligation.predicate); let new_universe = infcx.universe(); let placeholder_obligation = obligation.with(infcx.tcx, placeholder_predicate); @@ -1615,32 +1615,44 @@ fn assemble_candidates_from_trait_def<'cx, 'tcx>( candidate_set: &mut ProjectionCandidateSet<'tcx>, ) { debug!("assemble_candidates_from_trait_def(..)"); + let mut ambiguous = false; + selcx.for_each_item_bound( + obligation.predicate.self_ty(), + |selcx, clause, _| { + let Some(clause) = clause.as_projection_clause() else { + return ControlFlow::Continue(()); + }; - let tcx = selcx.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() { - // Excluding IATs and type aliases here as they don't have meaningful item bounds. - ty::Alias(ty::Projection | ty::Opaque, ref data) => { - tcx.item_bounds(data.def_id).instantiate(tcx, data.args) - } - 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. - candidate_set.mark_ambiguous(); - return; - } - _ => return, - }; + let is_match = + selcx.infcx.probe(|_| selcx.match_projection_projections(obligation, clause, true)); - assemble_candidates_from_predicates( - selcx, - obligation, - candidate_set, - ProjectionCandidate::TraitDef, - bounds.iter(), - true, + match is_match { + ProjectionMatchesProjection::Yes => { + candidate_set.push_candidate(ProjectionCandidate::TraitDef(clause)); + + if !obligation.predicate.has_non_region_infer() { + // HACK: Pick the first trait def candidate for a fully + // inferred predicate. This is to allow duplicates that + // differ only in normalization. + return ControlFlow::Break(()); + } + } + ProjectionMatchesProjection::Ambiguous => { + candidate_set.mark_ambiguous(); + } + ProjectionMatchesProjection::No => {} + } + + ControlFlow::Continue(()) + }, + // `ProjectionCandidateSet` is borrowed in the above closure, + // so just mark ambiguous outside of the closure. + || ambiguous = true, ); + + if ambiguous { + candidate_set.mark_ambiguous(); + } } /// In the case of a trait object like @@ -1936,10 +1948,11 @@ fn assemble_candidates_from_impls<'cx, 'tcx>( // Integers and floats are always Sized, and so have unit type metadata. | ty::Infer(ty::InferTy::IntVar(_) | ty::InferTy::FloatVar(..)) => true, - // type parameters, opaques, and unnormalized projections have pointer - // metadata if they're known (e.g. by the param_env) to be sized + // We normalize from `Wrapper<Tail>::Metadata` to `Tail::Metadata` if able. + // Otherwise, type parameters, opaques, and unnormalized projections have + // unit metadata if they're known (e.g. by the param_env) to be sized. ty::Param(_) | ty::Alias(..) - if selcx.infcx.predicate_must_hold_modulo_regions( + if self_ty != tail || selcx.infcx.predicate_must_hold_modulo_regions( &obligation.with( selcx.tcx(), ty::TraitRef::from_lang_item(selcx.tcx(), LangItem::Sized, obligation.cause.span(),[self_ty]), @@ -2074,7 +2087,9 @@ fn confirm_select_candidate<'cx, 'tcx>( } else if lang_items.async_iterator_trait() == Some(trait_def_id) { confirm_async_iterator_candidate(selcx, obligation, data) } else if selcx.tcx().fn_trait_kind_from_def_id(trait_def_id).is_some() { - if obligation.predicate.self_ty().is_closure() { + if obligation.predicate.self_ty().is_closure() + || obligation.predicate.self_ty().is_coroutine_closure() + { confirm_closure_candidate(selcx, obligation, data) } else { confirm_fn_pointer_candidate(selcx, obligation, data) @@ -2313,7 +2328,7 @@ fn confirm_builtin_candidate<'cx, 'tcx>( assert_eq!(metadata_def_id, item_def_id); let mut obligations = Vec::new(); - let (metadata_ty, check_is_sized) = self_ty.ptr_metadata_ty(tcx, |ty| { + let normalize = |ty| { normalize_with_depth_to( selcx, obligation.param_env, @@ -2322,16 +2337,27 @@ fn confirm_builtin_candidate<'cx, 'tcx>( ty, &mut obligations, ) + }; + let metadata_ty = self_ty.ptr_metadata_ty_or_tail(tcx, normalize).unwrap_or_else(|tail| { + if tail == self_ty { + // This is the "fallback impl" for type parameters, unnormalizable projections + // and opaque types: If the `self_ty` is `Sized`, then the metadata is `()`. + // FIXME(ptr_metadata): This impl overlaps with the other impls and shouldn't + // exist. Instead, `Pointee<Metadata = ()>` should be a supertrait of `Sized`. + let sized_predicate = ty::TraitRef::from_lang_item( + tcx, + LangItem::Sized, + obligation.cause.span(), + [self_ty], + ); + obligations.push(obligation.with(tcx, sized_predicate)); + tcx.types.unit + } else { + // We know that `self_ty` has the same metadata as `tail`. This allows us + // to prove predicates like `Wrapper<Tail>::Metadata == Tail::Metadata`. + Ty::new_projection(tcx, metadata_def_id, [tail]) + } }); - if check_is_sized { - let sized_predicate = ty::TraitRef::from_lang_item( - tcx, - LangItem::Sized, - obligation.cause.span(), - [self_ty], - ); - obligations.push(obligation.with(tcx, sized_predicate)); - } (metadata_ty.into(), obligations) } else { bug!("unexpected builtin trait with associated type: {:?}", obligation.predicate); @@ -2386,11 +2412,75 @@ fn confirm_closure_candidate<'cx, 'tcx>( obligation: &ProjectionTyObligation<'tcx>, nested: Vec<PredicateObligation<'tcx>>, ) -> Progress<'tcx> { + let tcx = selcx.tcx(); let self_ty = selcx.infcx.shallow_resolve(obligation.predicate.self_ty()); - let ty::Closure(_, args) = self_ty.kind() else { - unreachable!("expected closure self type for closure candidate, found {self_ty}") + let closure_sig = match *self_ty.kind() { + ty::Closure(_, args) => args.as_closure().sig(), + + // Construct a "normal" `FnOnce` signature for coroutine-closure. This is + // basically duplicated with the `AsyncFnOnce::CallOnce` confirmation, but + // I didn't see a good way to unify those. + ty::CoroutineClosure(def_id, args) => { + let args = args.as_coroutine_closure(); + let kind_ty = args.kind_ty(); + args.coroutine_closure_sig().map_bound(|sig| { + // If we know the kind and upvars, use that directly. + // Otherwise, defer to `AsyncFnKindHelper::Upvars` to delay + // the projection, like the `AsyncFn*` traits do. + let output_ty = if let Some(_) = kind_ty.to_opt_closure_kind() { + sig.to_coroutine_given_kind_and_upvars( + tcx, + args.parent_args(), + tcx.coroutine_for_closure(def_id), + ty::ClosureKind::FnOnce, + tcx.lifetimes.re_static, + args.tupled_upvars_ty(), + args.coroutine_captures_by_ref_ty(), + ) + } else { + let async_fn_kind_trait_def_id = + tcx.require_lang_item(LangItem::AsyncFnKindHelper, None); + let upvars_projection_def_id = tcx + .associated_items(async_fn_kind_trait_def_id) + .filter_by_name_unhygienic(sym::Upvars) + .next() + .unwrap() + .def_id; + let tupled_upvars_ty = Ty::new_projection( + tcx, + upvars_projection_def_id, + [ + ty::GenericArg::from(kind_ty), + Ty::from_closure_kind(tcx, ty::ClosureKind::FnOnce).into(), + tcx.lifetimes.re_static.into(), + sig.tupled_inputs_ty.into(), + args.tupled_upvars_ty().into(), + args.coroutine_captures_by_ref_ty().into(), + ], + ); + sig.to_coroutine( + tcx, + args.parent_args(), + Ty::from_closure_kind(tcx, ty::ClosureKind::FnOnce), + tcx.coroutine_for_closure(def_id), + tupled_upvars_ty, + ) + }; + tcx.mk_fn_sig( + [sig.tupled_inputs_ty], + output_ty, + sig.c_variadic, + sig.unsafety, + sig.abi, + ) + }) + } + + _ => { + unreachable!("expected closure self type for closure candidate, found {self_ty}"); + } }; - let closure_sig = args.as_closure().sig(); + let Normalized { value: closure_sig, obligations } = normalize_with_depth( selcx, obligation.param_env, @@ -2446,126 +2536,171 @@ fn confirm_callable_candidate<'cx, 'tcx>( fn confirm_async_closure_candidate<'cx, 'tcx>( selcx: &mut SelectionContext<'cx, 'tcx>, obligation: &ProjectionTyObligation<'tcx>, - mut nested: Vec<PredicateObligation<'tcx>>, + nested: Vec<PredicateObligation<'tcx>>, ) -> Progress<'tcx> { + let tcx = selcx.tcx(); let self_ty = selcx.infcx.shallow_resolve(obligation.predicate.self_ty()); - let ty::CoroutineClosure(def_id, args) = *self_ty.kind() else { - unreachable!( - "expected coroutine-closure self type for coroutine-closure candidate, found {self_ty}" - ) - }; - let args = args.as_coroutine_closure(); - let kind_ty = args.kind_ty(); - let tcx = selcx.tcx(); let goal_kind = tcx.async_fn_trait_kind_from_def_id(obligation.predicate.trait_def_id(tcx)).unwrap(); - - let async_fn_kind_helper_trait_def_id = - tcx.require_lang_item(LangItem::AsyncFnKindHelper, None); - nested.push(obligation.with( - tcx, - ty::TraitRef::new( - tcx, - async_fn_kind_helper_trait_def_id, - [kind_ty, Ty::from_closure_kind(tcx, goal_kind)], - ), - )); - let env_region = match goal_kind { ty::ClosureKind::Fn | ty::ClosureKind::FnMut => obligation.predicate.args.region_at(2), ty::ClosureKind::FnOnce => tcx.lifetimes.re_static, }; - - let upvars_projection_def_id = tcx - .associated_items(async_fn_kind_helper_trait_def_id) - .filter_by_name_unhygienic(sym::Upvars) - .next() - .unwrap() - .def_id; - - // FIXME(async_closures): Confirmation is kind of a mess here. Ideally, - // we'd short-circuit when we know that the goal_kind >= closure_kind, and not - // register a nested predicate or create a new projection ty here. But I'm too - // lazy to make this more efficient atm, and we can always tweak it later, - // since all this does is make the solver do more work. - // - // The code duplication due to the different length args is kind of weird, too. - // - // See the logic in `structural_traits` in the new solver to understand a bit - // more clearly how this *should* look. - let poly_cache_entry = args.coroutine_closure_sig().map_bound(|sig| { - let (projection_ty, term) = match tcx.item_name(obligation.predicate.def_id) { - sym::CallOnceFuture => { - let tupled_upvars_ty = Ty::new_projection( + let item_name = tcx.item_name(obligation.predicate.def_id); + + let poly_cache_entry = match *self_ty.kind() { + ty::CoroutineClosure(def_id, args) => { + let args = args.as_coroutine_closure(); + let kind_ty = args.kind_ty(); + let sig = args.coroutine_closure_sig().skip_binder(); + + let term = match item_name { + sym::CallOnceFuture | sym::CallMutFuture | sym::CallFuture => { + if let Some(closure_kind) = kind_ty.to_opt_closure_kind() { + if !closure_kind.extends(goal_kind) { + bug!("we should not be confirming if the closure kind is not met"); + } + sig.to_coroutine_given_kind_and_upvars( + tcx, + args.parent_args(), + tcx.coroutine_for_closure(def_id), + goal_kind, + env_region, + args.tupled_upvars_ty(), + args.coroutine_captures_by_ref_ty(), + ) + } else { + let async_fn_kind_trait_def_id = + tcx.require_lang_item(LangItem::AsyncFnKindHelper, None); + let upvars_projection_def_id = tcx + .associated_items(async_fn_kind_trait_def_id) + .filter_by_name_unhygienic(sym::Upvars) + .next() + .unwrap() + .def_id; + // When we don't know the closure kind (and therefore also the closure's upvars, + // which are computed at the same time), we must delay the computation of the + // generator's upvars. We do this using the `AsyncFnKindHelper`, which as a trait + // goal functions similarly to the old `ClosureKind` predicate, and ensures that + // the goal kind <= the closure kind. As a projection `AsyncFnKindHelper::Upvars` + // will project to the right upvars for the generator, appending the inputs and + // coroutine upvars respecting the closure kind. + // N.B. No need to register a `AsyncFnKindHelper` goal here, it's already in `nested`. + let tupled_upvars_ty = Ty::new_projection( + tcx, + upvars_projection_def_id, + [ + ty::GenericArg::from(kind_ty), + Ty::from_closure_kind(tcx, goal_kind).into(), + env_region.into(), + sig.tupled_inputs_ty.into(), + args.tupled_upvars_ty().into(), + args.coroutine_captures_by_ref_ty().into(), + ], + ); + sig.to_coroutine( + tcx, + args.parent_args(), + Ty::from_closure_kind(tcx, goal_kind), + tcx.coroutine_for_closure(def_id), + tupled_upvars_ty, + ) + } + } + sym::Output => sig.return_ty, + name => bug!("no such associated type: {name}"), + }; + let projection_ty = match item_name { + sym::CallOnceFuture | sym::Output => ty::AliasTy::new( tcx, - upvars_projection_def_id, - [ - ty::GenericArg::from(kind_ty), - Ty::from_closure_kind(tcx, goal_kind).into(), - env_region.into(), - sig.tupled_inputs_ty.into(), - args.tupled_upvars_ty().into(), - args.coroutine_captures_by_ref_ty().into(), - ], - ); - let coroutine_ty = sig.to_coroutine( + obligation.predicate.def_id, + [self_ty, sig.tupled_inputs_ty], + ), + sym::CallMutFuture | sym::CallFuture => ty::AliasTy::new( tcx, - args.parent_args(), - Ty::from_closure_kind(tcx, goal_kind), - tcx.coroutine_for_closure(def_id), - tupled_upvars_ty, - ); - ( - ty::AliasTy::new( - tcx, - obligation.predicate.def_id, - [self_ty, sig.tupled_inputs_ty], - ), - coroutine_ty.into(), - ) - } - sym::CallMutFuture | sym::CallFuture => { - let tupled_upvars_ty = Ty::new_projection( + obligation.predicate.def_id, + [ty::GenericArg::from(self_ty), sig.tupled_inputs_ty.into(), env_region.into()], + ), + name => bug!("no such associated type: {name}"), + }; + + args.coroutine_closure_sig() + .rebind(ty::ProjectionPredicate { projection_ty, term: term.into() }) + } + ty::FnDef(..) | ty::FnPtr(..) => { + let bound_sig = self_ty.fn_sig(tcx); + let sig = bound_sig.skip_binder(); + + let term = match item_name { + sym::CallOnceFuture | sym::CallMutFuture | sym::CallFuture => sig.output(), + sym::Output => { + let future_trait_def_id = tcx.require_lang_item(LangItem::Future, None); + let future_output_def_id = tcx + .associated_items(future_trait_def_id) + .filter_by_name_unhygienic(sym::Output) + .next() + .unwrap() + .def_id; + Ty::new_projection(tcx, future_output_def_id, [sig.output()]) + } + name => bug!("no such associated type: {name}"), + }; + let projection_ty = match item_name { + sym::CallOnceFuture | sym::Output => ty::AliasTy::new( tcx, - upvars_projection_def_id, + obligation.predicate.def_id, + [self_ty, Ty::new_tup(tcx, sig.inputs())], + ), + sym::CallMutFuture | sym::CallFuture => ty::AliasTy::new( + tcx, + obligation.predicate.def_id, [ - ty::GenericArg::from(kind_ty), - Ty::from_closure_kind(tcx, goal_kind).into(), + ty::GenericArg::from(self_ty), + Ty::new_tup(tcx, sig.inputs()).into(), env_region.into(), - sig.tupled_inputs_ty.into(), - args.tupled_upvars_ty().into(), - args.coroutine_captures_by_ref_ty().into(), ], - ); - let coroutine_ty = sig.to_coroutine( + ), + name => bug!("no such associated type: {name}"), + }; + + bound_sig.rebind(ty::ProjectionPredicate { projection_ty, term: term.into() }) + } + ty::Closure(_, args) => { + let args = args.as_closure(); + let bound_sig = args.sig(); + let sig = bound_sig.skip_binder(); + + let term = match item_name { + sym::CallOnceFuture | sym::CallMutFuture | sym::CallFuture => sig.output(), + sym::Output => { + let future_trait_def_id = tcx.require_lang_item(LangItem::Future, None); + let future_output_def_id = tcx + .associated_items(future_trait_def_id) + .filter_by_name_unhygienic(sym::Output) + .next() + .unwrap() + .def_id; + Ty::new_projection(tcx, future_output_def_id, [sig.output()]) + } + name => bug!("no such associated type: {name}"), + }; + let projection_ty = match item_name { + sym::CallOnceFuture | sym::Output => { + ty::AliasTy::new(tcx, obligation.predicate.def_id, [self_ty, sig.inputs()[0]]) + } + sym::CallMutFuture | sym::CallFuture => ty::AliasTy::new( tcx, - args.parent_args(), - Ty::from_closure_kind(tcx, goal_kind), - tcx.coroutine_for_closure(def_id), - tupled_upvars_ty, - ); - ( - ty::AliasTy::new( - tcx, - obligation.predicate.def_id, - [ - ty::GenericArg::from(self_ty), - sig.tupled_inputs_ty.into(), - env_region.into(), - ], - ), - coroutine_ty.into(), - ) - } - sym::Output => ( - ty::AliasTy::new(tcx, obligation.predicate.def_id, [self_ty, sig.tupled_inputs_ty]), - sig.return_ty.into(), - ), - name => bug!("no such associated type: {name}"), - }; - ty::ProjectionPredicate { projection_ty, term } - }); + obligation.predicate.def_id, + [ty::GenericArg::from(self_ty), sig.inputs()[0].into(), env_region.into()], + ), + name => bug!("no such associated type: {name}"), + }; + + bound_sig.rebind(ty::ProjectionPredicate { projection_ty, term: term.into() }) + } + _ => bug!("expected callable type for AsyncFn candidate"), + }; confirm_param_env_candidate(selcx, obligation, poly_cache_entry, true) .with_addl_obligations(nested) diff --git a/compiler/rustc_trait_selection/src/traits/query/evaluate_obligation.rs b/compiler/rustc_trait_selection/src/traits/query/evaluate_obligation.rs index 4c0c57377e0..a050b30317a 100644 --- a/compiler/rustc_trait_selection/src/traits/query/evaluate_obligation.rs +++ b/compiler/rustc_trait_selection/src/traits/query/evaluate_obligation.rs @@ -41,7 +41,28 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> { /// not entirely accurate if inference variables are involved. /// /// This version may conservatively fail when outlives obligations - /// are required. + /// are required. Therefore, this version should only be used for + /// optimizations or diagnostics and be treated as if it can always + /// return `false`. + /// + /// # Example + /// + /// ``` + /// # #![allow(dead_code)] + /// trait Trait {} + /// + /// fn check<T: Trait>() {} + /// + /// fn foo<T: 'static>() + /// where + /// &'static T: Trait, + /// { + /// // Evaluating `&'?0 T: Trait` adds a `'?0: 'static` outlives obligation, + /// // which means that `predicate_must_hold_considering_regions` will return + /// // `false`. + /// check::<&'_ T>(); + /// } + /// ``` fn predicate_must_hold_considering_regions( &self, obligation: &PredicateObligation<'tcx>, 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 2258e796103..f9a292c2bd7 100644 --- a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs +++ b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs @@ -6,13 +6,16 @@ //! //! [rustc dev guide]:https://rustc-dev-guide.rust-lang.org/traits/resolution.html#candidate-assembly +use std::ops::ControlFlow; + use hir::def_id::DefId; use hir::LangItem; +use rustc_data_structures::fx::FxHashSet; use rustc_hir as hir; use rustc_infer::traits::ObligationCause; use rustc_infer::traits::{Obligation, PolyTraitObligation, SelectionError}; use rustc_middle::ty::fast_reject::{DeepRejectCtxt, TreatParams}; -use rustc_middle::ty::{self, Ty, TypeVisitableExt}; +use rustc_middle::ty::{self, ToPolyTraitRef, Ty, TypeVisitableExt}; use crate::traits; use crate::traits::query::evaluate_obligation::InferCtxtExt; @@ -158,11 +161,50 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { _ => return, } - let result = self - .infcx - .probe(|_| self.match_projection_obligation_against_definition_bounds(obligation)); + self.infcx.probe(|_| { + let poly_trait_predicate = self.infcx.resolve_vars_if_possible(obligation.predicate); + let placeholder_trait_predicate = + self.infcx.enter_forall_and_leak_universe(poly_trait_predicate); + debug!(?placeholder_trait_predicate); + + // The bounds returned by `item_bounds` may contain duplicates after + // normalization, so try to deduplicate when possible to avoid + // unnecessary ambiguity. + let mut distinct_normalized_bounds = FxHashSet::default(); + self.for_each_item_bound::<!>( + placeholder_trait_predicate.self_ty(), + |selcx, bound, idx| { + let Some(bound) = bound.as_trait_clause() else { + return ControlFlow::Continue(()); + }; + if bound.polarity() != placeholder_trait_predicate.polarity { + return ControlFlow::Continue(()); + } + + selcx.infcx.probe(|_| { + match selcx.match_normalize_trait_ref( + obligation, + bound.to_poly_trait_ref(), + placeholder_trait_predicate.trait_ref, + ) { + Ok(None) => { + candidates.vec.push(ProjectionCandidate(idx)); + } + Ok(Some(normalized_trait)) + if distinct_normalized_bounds.insert(normalized_trait) => + { + candidates.vec.push(ProjectionCandidate(idx)); + } + _ => {} + } + }); - candidates.vec.extend(result.into_iter().map(|idx| ProjectionCandidate(idx))); + ControlFlow::Continue(()) + }, + // On ambiguity. + || candidates.ambiguous = true, + ); + }); } /// Given an obligation like `<SomeTrait for T>`, searches the obligations that the caller @@ -332,6 +374,43 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { } } } + ty::CoroutineClosure(def_id, args) => { + let is_const = self.tcx().is_const_fn_raw(def_id); + match self.infcx.closure_kind(self_ty) { + Some(closure_kind) => { + let no_borrows = match self + .infcx + .shallow_resolve(args.as_coroutine_closure().tupled_upvars_ty()) + .kind() + { + ty::Tuple(tys) => tys.is_empty(), + ty::Error(_) => false, + _ => bug!("tuple_fields called on non-tuple"), + }; + // A coroutine-closure implements `FnOnce` *always*, since it may + // always be called once. It additionally implements `Fn`/`FnMut` + // only if it has no upvars (therefore no borrows from the closure + // that would need to be represented with a lifetime) and if the + // closure kind permits it. + // FIXME(async_closures): Actually, it could also implement `Fn`/`FnMut` + // if it takes all of its upvars by copy, and none by ref. This would + // require us to record a bit more information during upvar analysis. + if no_borrows && closure_kind.extends(kind) { + candidates.vec.push(ClosureCandidate { is_const }); + } else if kind == ty::ClosureKind::FnOnce { + candidates.vec.push(ClosureCandidate { is_const }); + } + } + None => { + if kind == ty::ClosureKind::FnOnce { + candidates.vec.push(ClosureCandidate { is_const }); + } else { + // This stays ambiguous until kind+upvars are determined. + candidates.ambiguous = true; + } + } + } + } ty::Infer(ty::TyVar(_)) => { debug!("assemble_unboxed_closure_candidates: ambiguous self-type"); candidates.ambiguous = true; @@ -361,8 +440,18 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { } candidates.vec.push(AsyncClosureCandidate); } - ty::Infer(ty::TyVar(_)) => { - candidates.ambiguous = true; + // Closures and fn pointers implement `AsyncFn*` if their return types + // implement `Future`, which is checked later. + ty::Closure(_, args) => { + if let Some(closure_kind) = args.as_closure().kind_ty().to_opt_closure_kind() + && !closure_kind.extends(goal_kind) + { + return; + } + candidates.vec.push(AsyncClosureCandidate); + } + ty::FnDef(..) | ty::FnPtr(..) => { + candidates.vec.push(AsyncClosureCandidate); } _ => {} } @@ -728,64 +817,63 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { self.infcx.probe(|_snapshot| { let poly_trait_predicate = self.infcx.resolve_vars_if_possible(obligation.predicate); - let placeholder_trait_predicate = - self.infcx.instantiate_binder_with_placeholders(poly_trait_predicate); - - let self_ty = placeholder_trait_predicate.self_ty(); - let principal_trait_ref = match self_ty.kind() { - ty::Dynamic(data, ..) => { - if data.auto_traits().any(|did| did == obligation.predicate.def_id()) { - debug!( - "assemble_candidates_from_object_ty: matched builtin bound, \ + self.infcx.enter_forall(poly_trait_predicate, |placeholder_trait_predicate| { + let self_ty = placeholder_trait_predicate.self_ty(); + let principal_trait_ref = match self_ty.kind() { + ty::Dynamic(data, ..) => { + if data.auto_traits().any(|did| did == obligation.predicate.def_id()) { + debug!( + "assemble_candidates_from_object_ty: matched builtin bound, \ pushing candidate" - ); - candidates.vec.push(BuiltinObjectCandidate); - return; - } + ); + candidates.vec.push(BuiltinObjectCandidate); + return; + } - if let Some(principal) = data.principal() { - if !self.infcx.tcx.features().object_safe_for_dispatch { - principal.with_self_ty(self.tcx(), self_ty) - } else if self.tcx().check_is_object_safe(principal.def_id()) { - principal.with_self_ty(self.tcx(), self_ty) + if let Some(principal) = data.principal() { + if !self.infcx.tcx.features().object_safe_for_dispatch { + principal.with_self_ty(self.tcx(), self_ty) + } else if self.tcx().check_is_object_safe(principal.def_id()) { + principal.with_self_ty(self.tcx(), self_ty) + } else { + return; + } } else { + // Only auto trait bounds exist. return; } - } else { - // Only auto trait bounds exist. + } + ty::Infer(ty::TyVar(_)) => { + debug!("assemble_candidates_from_object_ty: ambiguous"); + candidates.ambiguous = true; // could wind up being an object type return; } - } - ty::Infer(ty::TyVar(_)) => { - debug!("assemble_candidates_from_object_ty: ambiguous"); - candidates.ambiguous = true; // could wind up being an object type - return; - } - _ => return, - }; - - debug!(?principal_trait_ref, "assemble_candidates_from_object_ty"); - - // Count only those upcast versions that match the trait-ref - // we are looking for. Specifically, do not only check for the - // correct trait, but also the correct type parameters. - // For example, we may be trying to upcast `Foo` to `Bar<i32>`, - // but `Foo` is declared as `trait Foo: Bar<u32>`. - let candidate_supertraits = util::supertraits(self.tcx(), principal_trait_ref) - .enumerate() - .filter(|&(_, upcast_trait_ref)| { - self.infcx.probe(|_| { - self.match_normalize_trait_ref( - obligation, - upcast_trait_ref, - placeholder_trait_predicate.trait_ref, - ) - .is_ok() + _ => return, + }; + + debug!(?principal_trait_ref, "assemble_candidates_from_object_ty"); + + // Count only those upcast versions that match the trait-ref + // we are looking for. Specifically, do not only check for the + // correct trait, but also the correct type parameters. + // For example, we may be trying to upcast `Foo` to `Bar<i32>`, + // but `Foo` is declared as `trait Foo: Bar<u32>`. + let candidate_supertraits = util::supertraits(self.tcx(), principal_trait_ref) + .enumerate() + .filter(|&(_, upcast_trait_ref)| { + self.infcx.probe(|_| { + self.match_normalize_trait_ref( + obligation, + upcast_trait_ref, + placeholder_trait_predicate.trait_ref, + ) + .is_ok() + }) }) - }) - .map(|(idx, _)| ObjectCandidate(idx)); + .map(|(idx, _)| ObjectCandidate(idx)); - candidates.vec.extend(candidate_supertraits); + candidates.vec.extend(candidate_supertraits); + }) }) } diff --git a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs index c9d06b0f675..6ca24933979 100644 --- a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs +++ b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs @@ -159,23 +159,29 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { let trait_predicate = self.infcx.shallow_resolve(obligation.predicate); let placeholder_trait_predicate = - self.infcx.instantiate_binder_with_placeholders(trait_predicate).trait_ref; + self.infcx.enter_forall_and_leak_universe(trait_predicate).trait_ref; let placeholder_self_ty = placeholder_trait_predicate.self_ty(); let placeholder_trait_predicate = ty::Binder::dummy(placeholder_trait_predicate); - let (def_id, args) = match *placeholder_self_ty.kind() { - // Excluding IATs and type aliases here as they don't have meaningful item bounds. - ty::Alias(ty::Projection | ty::Opaque, ty::AliasTy { def_id, args, .. }) => { - (def_id, args) - } - _ => bug!("projection candidate for unexpected type: {:?}", placeholder_self_ty), - }; - let candidate_predicate = - tcx.item_bounds(def_id).map_bound(|i| i[idx]).instantiate(tcx, args); + let candidate_predicate = self + .for_each_item_bound( + placeholder_self_ty, + |_, clause, clause_idx| { + if clause_idx == idx { + ControlFlow::Break(clause) + } else { + ControlFlow::Continue(()) + } + }, + || unreachable!(), + ) + .break_value() + .expect("expected to index into clause that exists"); let candidate = candidate_predicate .as_trait_clause() .expect("projection candidate is not a trait predicate") .map_bound(|t| t.trait_ref); + let mut obligations = Vec::new(); let candidate = normalize_with_depth_to( self, @@ -194,8 +200,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { .map_err(|_| Unimplemented) })?); - if let ty::Alias(ty::Projection, ..) = placeholder_self_ty.kind() { - let predicates = tcx.predicates_of(def_id).instantiate_own(tcx, args); + // FIXME(compiler-errors): I don't think this is needed. + if let ty::Alias(ty::Projection, alias_ty) = placeholder_self_ty.kind() { + let predicates = tcx.predicates_of(alias_ty.def_id).instantiate_own(tcx, alias_ty.args); for (predicate, _) in predicates { let normalized = normalize_with_depth_to( self, @@ -402,7 +409,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { let cause = obligation.derived_cause(BuiltinDerivedObligation); let poly_trait_ref = obligation.predicate.to_poly_trait_ref(); - let trait_ref = self.infcx.instantiate_binder_with_placeholders(poly_trait_ref); + let trait_ref = self.infcx.enter_forall_and_leak_universe(poly_trait_ref); let trait_obligations: Vec<PredicateObligation<'_>> = self.impl_or_trait_obligations( &cause, obligation.recursion_depth + 1, @@ -493,7 +500,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { let tcx = self.tcx(); debug!(?obligation, ?index, "confirm_object_candidate"); - let trait_predicate = self.infcx.instantiate_binder_with_placeholders(obligation.predicate); + let trait_predicate = self.infcx.enter_forall_and_leak_universe(obligation.predicate); let self_ty = self.infcx.shallow_resolve(trait_predicate.self_ty()); let obligation_trait_ref = ty::Binder::dummy(trait_predicate.trait_ref); let ty::Dynamic(data, ..) = *self_ty.kind() else { @@ -691,7 +698,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { let cause = obligation.derived_cause(BuiltinDerivedObligation); // Confirm the `type Output: Sized;` bound that is present on `FnOnce` - let output_ty = self.infcx.instantiate_binder_with_placeholders(sig.output()); + let output_ty = self.infcx.enter_forall_and_leak_universe(sig.output()); let output_ty = normalize_with_depth_to( self, obligation.param_env, @@ -712,7 +719,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { ) -> Vec<PredicateObligation<'tcx>> { debug!(?obligation, "confirm_trait_alias_candidate"); - let predicate = self.infcx.instantiate_binder_with_placeholders(obligation.predicate); + let predicate = self.infcx.enter_forall_and_leak_universe(obligation.predicate); let trait_ref = predicate.trait_ref; let trait_def_id = trait_ref.def_id; let args = trait_ref.args; @@ -865,17 +872,25 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { // touch bound regions, they just capture the in-scope // type/region parameters. let self_ty = self.infcx.shallow_resolve(obligation.self_ty().skip_binder()); - let ty::Closure(closure_def_id, args) = *self_ty.kind() else { - bug!("closure candidate for non-closure {:?}", obligation); + let trait_ref = match *self_ty.kind() { + ty::Closure(_, args) => { + self.closure_trait_ref_unnormalized(obligation, args, self.tcx().consts.true_) + } + ty::CoroutineClosure(_, args) => { + args.as_coroutine_closure().coroutine_closure_sig().map_bound(|sig| { + ty::TraitRef::new( + self.tcx(), + obligation.predicate.def_id(), + [self_ty, sig.tupled_inputs_ty], + ) + }) + } + _ => { + bug!("closure candidate for non-closure {:?}", obligation); + } }; - let trait_ref = - self.closure_trait_ref_unnormalized(obligation, args, self.tcx().consts.true_); - let nested = self.confirm_poly_trait_refs(obligation, trait_ref)?; - - debug!(?closure_def_id, ?trait_ref, ?nested, "confirm closure candidate obligations"); - - Ok(nested) + self.confirm_poly_trait_refs(obligation, trait_ref) } #[instrument(skip(self), level = "debug")] @@ -883,40 +898,86 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { &mut self, obligation: &PolyTraitObligation<'tcx>, ) -> Result<Vec<PredicateObligation<'tcx>>, SelectionError<'tcx>> { - // Okay to skip binder because the args on closure types never - // touch bound regions, they just capture the in-scope - // type/region parameters. + let tcx = self.tcx(); let self_ty = self.infcx.shallow_resolve(obligation.self_ty().skip_binder()); - let ty::CoroutineClosure(closure_def_id, args) = *self_ty.kind() else { - bug!("async closure candidate for non-coroutine-closure {:?}", obligation); - }; - let trait_ref = args.as_coroutine_closure().coroutine_closure_sig().map_bound(|sig| { - ty::TraitRef::new( - self.tcx(), - obligation.predicate.def_id(), - [self_ty, sig.tupled_inputs_ty], - ) - }); + let mut nested = vec![]; + let (trait_ref, kind_ty) = match *self_ty.kind() { + ty::CoroutineClosure(_, args) => { + let args = args.as_coroutine_closure(); + let trait_ref = args.coroutine_closure_sig().map_bound(|sig| { + ty::TraitRef::new( + self.tcx(), + obligation.predicate.def_id(), + [self_ty, sig.tupled_inputs_ty], + ) + }); + (trait_ref, args.kind_ty()) + } + ty::FnDef(..) | ty::FnPtr(..) => { + let sig = self_ty.fn_sig(tcx); + let trait_ref = sig.map_bound(|sig| { + ty::TraitRef::new( + self.tcx(), + obligation.predicate.def_id(), + [self_ty, Ty::new_tup(tcx, sig.inputs())], + ) + }); + // We must additionally check that the return type impls `Future`. + let future_trait_def_id = tcx.require_lang_item(LangItem::Future, None); + nested.push(obligation.with( + tcx, + sig.map_bound(|sig| { + ty::TraitRef::new(tcx, future_trait_def_id, [sig.output()]) + }), + )); + (trait_ref, Ty::from_closure_kind(tcx, ty::ClosureKind::Fn)) + } + ty::Closure(_, args) => { + let sig = args.as_closure().sig(); + let trait_ref = sig.map_bound(|sig| { + ty::TraitRef::new( + self.tcx(), + obligation.predicate.def_id(), + [self_ty, sig.inputs()[0]], + ) + }); + // We must additionally check that the return type impls `Future`. + let future_trait_def_id = tcx.require_lang_item(LangItem::Future, None); + nested.push(obligation.with( + tcx, + sig.map_bound(|sig| { + ty::TraitRef::new(tcx, future_trait_def_id, [sig.output()]) + }), + )); + (trait_ref, Ty::from_closure_kind(tcx, ty::ClosureKind::Fn)) + } + _ => bug!("expected callable type for AsyncFn candidate"), + }; - let mut nested = self.confirm_poly_trait_refs(obligation, trait_ref)?; + nested.extend(self.confirm_poly_trait_refs(obligation, trait_ref)?); let goal_kind = self.tcx().async_fn_trait_kind_from_def_id(obligation.predicate.def_id()).unwrap(); - nested.push(obligation.with( - self.tcx(), - ty::TraitRef::from_lang_item( + + // If we have not yet determiend the `ClosureKind` of the closure or coroutine-closure, + // then additionally register an `AsyncFnKindHelper` goal which will fail if the kind + // is constrained to an insufficient type later on. + if let Some(closure_kind) = self.infcx.shallow_resolve(kind_ty).to_opt_closure_kind() { + if !closure_kind.extends(goal_kind) { + return Err(SelectionError::Unimplemented); + } + } else { + nested.push(obligation.with( self.tcx(), - LangItem::AsyncFnKindHelper, - obligation.cause.span, - [ - args.as_coroutine_closure().kind_ty(), - Ty::from_closure_kind(self.tcx(), goal_kind), - ], - ), - )); - - debug!(?closure_def_id, ?trait_ref, ?nested, "confirm closure candidate obligations"); + ty::TraitRef::from_lang_item( + self.tcx(), + LangItem::AsyncFnKindHelper, + obligation.cause.span, + [kind_ty, Ty::from_closure_kind(self.tcx(), goal_kind)], + ), + )); + } Ok(nested) } diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs index 7f41c73b72f..ac6cfcdeb59 100644 --- a/compiler/rustc_trait_selection/src/traits/select/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs @@ -52,6 +52,7 @@ use std::cell::{Cell, RefCell}; use std::cmp; use std::fmt::{self, Display}; use std::iter; +use std::ops::ControlFlow; pub use rustc_middle::traits::select::*; use rustc_middle::ty::print::with_no_trimmed_paths; @@ -483,7 +484,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { // Instead, we select the right impl now but report "`Bar` does // not implement `Clone`". if candidates.len() == 1 { - return self.filter_reservation_impls(candidates.pop().unwrap(), stack.obligation); + return self.filter_reservation_impls(candidates.pop().unwrap()); } // Winnow, but record the exact outcome of evaluation, which @@ -557,7 +558,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { } // Just one candidate left. - self.filter_reservation_impls(candidates.pop().unwrap().candidate, stack.obligation) + self.filter_reservation_impls(candidates.pop().unwrap().candidate) } /////////////////////////////////////////////////////////////////////////// @@ -1436,7 +1437,6 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { fn filter_reservation_impls( &mut self, candidate: SelectionCandidate<'tcx>, - obligation: &PolyTraitObligation<'tcx>, ) -> SelectionResult<'tcx, SelectionCandidate<'tcx>> { let tcx = self.tcx(); // Treat reservation impls as ambiguity. @@ -1593,71 +1593,41 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { self.infcx.selection_cache.insert((param_env, pred), dep_node, candidate); } - /// Matches a predicate against the bounds of its self type. - /// - /// Given an obligation like `<T as Foo>::Bar: Baz` where the self type is - /// a projection, look at the bounds of `T::Bar`, see if we can find a - /// `Baz` bound. We return indexes into the list returned by - /// `tcx.item_bounds` for any applicable bounds. - #[instrument(level = "debug", skip(self), ret)] - fn match_projection_obligation_against_definition_bounds( + /// Looks at the item bounds of the projection or opaque type. + /// If this is a nested rigid projection, such as + /// `<<T as Tr1>::Assoc as Tr2>::Assoc`, consider the item bounds + /// on both `Tr1::Assoc` and `Tr2::Assoc`, since we may encounter + /// relative bounds on both via the `associated_type_bounds` feature. + pub(super) fn for_each_item_bound<T>( &mut self, - obligation: &PolyTraitObligation<'tcx>, - ) -> smallvec::SmallVec<[usize; 2]> { - let poly_trait_predicate = self.infcx.resolve_vars_if_possible(obligation.predicate); - let placeholder_trait_predicate = - self.infcx.instantiate_binder_with_placeholders(poly_trait_predicate); - debug!(?placeholder_trait_predicate); - - let tcx = self.infcx.tcx; - let (def_id, args) = match *placeholder_trait_predicate.trait_ref.self_ty().kind() { - ty::Alias(ty::Projection | ty::Opaque, ty::AliasTy { def_id, args, .. }) => { - (def_id, args) - } - _ => { - span_bug!( - obligation.cause.span, - "match_projection_obligation_against_definition_bounds() called \ - but self-ty is not a projection: {:?}", - placeholder_trait_predicate.trait_ref.self_ty() - ); - } - }; - let bounds = tcx.item_bounds(def_id).instantiate(tcx, args); + mut self_ty: Ty<'tcx>, + mut for_each: impl FnMut(&mut Self, ty::Clause<'tcx>, usize) -> ControlFlow<T, ()>, + on_ambiguity: impl FnOnce(), + ) -> ControlFlow<T, ()> { + let mut idx = 0; + loop { + let (kind, alias_ty) = match *self_ty.kind() { + ty::Alias(kind @ (ty::Projection | ty::Opaque), alias_ty) => (kind, alias_ty), + ty::Infer(ty::TyVar(_)) => { + on_ambiguity(); + return ControlFlow::Continue(()); + } + _ => return ControlFlow::Continue(()), + }; - // The bounds returned by `item_bounds` may contain duplicates after - // normalization, so try to deduplicate when possible to avoid - // unnecessary ambiguity. - let mut distinct_normalized_bounds = FxHashSet::default(); + for bound in + self.tcx().item_bounds(alias_ty.def_id).instantiate(self.tcx(), alias_ty.args) + { + for_each(self, bound, idx)?; + idx += 1; + } - bounds - .iter() - .enumerate() - .filter_map(|(idx, bound)| { - let bound_predicate = bound.kind(); - if let ty::ClauseKind::Trait(pred) = bound_predicate.skip_binder() { - let bound = bound_predicate.rebind(pred.trait_ref); - if self.infcx.probe(|_| { - match self.match_normalize_trait_ref( - obligation, - bound, - placeholder_trait_predicate.trait_ref, - ) { - Ok(None) => true, - Ok(Some(normalized_trait)) - if distinct_normalized_bounds.insert(normalized_trait) => - { - true - } - _ => false, - } - }) { - return Some(idx); - } - } - None - }) - .collect() + if kind == ty::Projection { + self_ty = alias_ty.self_ty(); + } else { + return ControlFlow::Continue(()); + } + } } /// Equates the trait in `obligation` with trait bound. If the two traits @@ -2386,7 +2356,7 @@ impl<'tcx> SelectionContext<'_, 'tcx> { .flat_map(|ty| { let ty: ty::Binder<'tcx, Ty<'tcx>> = types.rebind(*ty); // <----/ - let placeholder_ty = self.infcx.instantiate_binder_with_placeholders(ty); + let placeholder_ty = self.infcx.enter_forall_and_leak_universe(ty); let Normalized { value: normalized_ty, mut obligations } = ensure_sufficient_stack(|| { project::normalize_with_depth( @@ -2472,7 +2442,7 @@ impl<'tcx> SelectionContext<'_, 'tcx> { obligation: &PolyTraitObligation<'tcx>, ) -> Result<Normalized<'tcx, GenericArgsRef<'tcx>>, ()> { let placeholder_obligation = - self.infcx.instantiate_binder_with_placeholders(obligation.predicate); + self.infcx.enter_forall_and_leak_universe(obligation.predicate); let placeholder_obligation_trait_ref = placeholder_obligation.trait_ref; let impl_args = self.infcx.fresh_args_for_item(obligation.cause.span, impl_def_id); diff --git a/compiler/rustc_trait_selection/src/traits/specialize/mod.rs b/compiler/rustc_trait_selection/src/traits/specialize/mod.rs index de08e7d2f03..8e0fa79c977 100644 --- a/compiler/rustc_trait_selection/src/traits/specialize/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/specialize/mod.rs @@ -446,7 +446,7 @@ fn report_conflicting_impls<'tcx>( match used_to_be_allowed { None => { let reported = if overlap.with_impl.is_local() - || tcx.orphan_check_impl(impl_def_id).is_ok() + || tcx.ensure().orphan_check_impl(impl_def_id).is_ok() { let mut err = tcx.dcx().struct_span_err(impl_span, msg); err.code(E0119); |