diff options
Diffstat (limited to 'compiler/rustc_trait_selection/src/traits')
24 files changed, 1269 insertions, 580 deletions
diff --git a/compiler/rustc_trait_selection/src/traits/auto_trait.rs b/compiler/rustc_trait_selection/src/traits/auto_trait.rs index 294c81d0b..bcdfa4f12 100644 --- a/compiler/rustc_trait_selection/src/traits/auto_trait.rs +++ b/compiler/rustc_trait_selection/src/traits/auto_trait.rs @@ -3,13 +3,14 @@ use super::*; +use crate::errors::UnableToConstructConstantValue; use crate::infer::region_constraints::{Constraint, RegionConstraintData}; use crate::infer::InferCtxt; use crate::traits::project::ProjectAndUnifyResult; use rustc_middle::mir::interpret::ErrorHandled; use rustc_middle::ty::fold::{TypeFolder, TypeSuperFoldable}; use rustc_middle::ty::visit::TypeVisitable; -use rustc_middle::ty::{Region, RegionVid, Term}; +use rustc_middle::ty::{Region, RegionVid}; use rustc_data_structures::fx::{FxHashMap, FxHashSet}; @@ -205,10 +206,8 @@ impl<'tcx> AutoTraitFinder<'tcx> { // At this point, we already have all of the bounds we need. FulfillmentContext is used // to store all of the necessary region/lifetime bounds in the InferContext, as well as // an additional sanity check. - let mut fulfill = <dyn TraitEngine<'tcx>>::new(tcx); - fulfill.register_bound(&infcx, full_env, ty, trait_did, ObligationCause::dummy()); - let errors = fulfill.select_all_or_error(&infcx); - + let errors = + super::fully_solve_bound(&infcx, ObligationCause::dummy(), full_env, ty, trait_did); if !errors.is_empty() { panic!("Unable to fulfill trait {:?} for '{:?}': {:?}", trait_did, ty, errors); } @@ -343,7 +342,7 @@ impl<'tcx> AutoTraitFinder<'tcx> { } } - let obligations = impl_source.clone().nested_obligations().into_iter(); + let obligations = impl_source.borrow_nested_obligations().iter().cloned(); if !self.evaluate_nested_obligations( ty, @@ -613,7 +612,7 @@ impl<'tcx> AutoTraitFinder<'tcx> { } fn is_self_referential_projection(&self, p: ty::PolyProjectionPredicate<'_>) -> bool { - if let Term::Ty(ty) = p.term().skip_binder() { + if let Some(ty) = p.term().skip_binder().ty() { matches!(ty.kind(), ty::Projection(proj) if proj == &p.skip_binder().projection_ty) } else { false @@ -832,8 +831,11 @@ impl<'tcx> AutoTraitFinder<'tcx> { Ok(None) => { let tcx = self.tcx; let def_id = unevaluated.def.did; - let reported = tcx.sess.struct_span_err(tcx.def_span(def_id), &format!("unable to construct a constant value for the unevaluated constant {:?}", unevaluated)).emit(); - + let reported = + tcx.sess.emit_err(UnableToConstructConstantValue { + span: tcx.def_span(def_id), + unevaluated: unevaluated.expand(), + }); Err(ErrorHandled::Reported(reported)) } Err(err) => Err(err), diff --git a/compiler/rustc_trait_selection/src/traits/codegen.rs b/compiler/rustc_trait_selection/src/traits/codegen.rs index c0700748c..08adbcbd4 100644 --- a/compiler/rustc_trait_selection/src/traits/codegen.rs +++ b/compiler/rustc_trait_selection/src/traits/codegen.rs @@ -18,8 +18,7 @@ use rustc_middle::ty::{self, TyCtxt}; /// obligations *could be* resolved if we wanted to. /// /// This also expects that `trait_ref` is fully normalized. -#[instrument(level = "debug", skip(tcx))] -pub fn codegen_fulfill_obligation<'tcx>( +pub fn codegen_select_candidate<'tcx>( tcx: TyCtxt<'tcx>, (param_env, trait_ref): (ty::ParamEnv<'tcx>, ty::PolyTraitRef<'tcx>), ) -> Result<&'tcx ImplSource<'tcx, ()>, CodegenObligationError> { @@ -74,7 +73,6 @@ pub fn codegen_fulfill_obligation<'tcx>( // (ouz-a) This is required for `type-alias-impl-trait/assoc-projection-ice.rs` to pass let _ = infcx.inner.borrow_mut().opaque_type_storage.take_opaque_types(); - debug!("Cache miss: {trait_ref:?} => {impl_source:?}"); Ok(&*tcx.arena.alloc(impl_source)) }) } diff --git a/compiler/rustc_trait_selection/src/traits/coherence.rs b/compiler/rustc_trait_selection/src/traits/coherence.rs index 1c8cdf4ca..292787d4d 100644 --- a/compiler/rustc_trait_selection/src/traits/coherence.rs +++ b/compiler/rustc_trait_selection/src/traits/coherence.rs @@ -6,18 +6,20 @@ use crate::infer::outlives::env::OutlivesEnvironment; use crate::infer::{CombinedSnapshot, InferOk}; +use crate::traits::outlives_bounds::InferCtxtExt as _; use crate::traits::select::IntercrateAmbiguityCause; use crate::traits::util::impl_subject_and_oblig; use crate::traits::SkipLeakCheck; use crate::traits::{ - self, FulfillmentContext, Normalized, Obligation, ObligationCause, PredicateObligation, - PredicateObligations, SelectionContext, TraitEngineExt, + self, Normalized, Obligation, ObligationCause, ObligationCtxt, PredicateObligation, + PredicateObligations, SelectionContext, }; use rustc_data_structures::fx::FxIndexSet; use rustc_errors::Diagnostic; -use rustc_hir::def_id::{DefId, LOCAL_CRATE}; +use rustc_hir::def_id::{DefId, CRATE_DEF_ID, LOCAL_CRATE}; +use rustc_hir::CRATE_HIR_ID; use rustc_infer::infer::{InferCtxt, TyCtxtInferExt}; -use rustc_infer::traits::{util, TraitEngine}; +use rustc_infer::traits::util; use rustc_middle::traits::specialization_graph::OverlapMode; use rustc_middle::ty::fast_reject::{DeepRejectCtxt, TreatParams}; use rustc_middle::ty::subst::Subst; @@ -302,13 +304,18 @@ fn negative_impl<'cx, 'tcx>( let impl_env = tcx.param_env(impl1_def_id); let subject1 = match traits::fully_normalize( &infcx, - FulfillmentContext::new(), ObligationCause::dummy(), impl_env, tcx.impl_subject(impl1_def_id), ) { Ok(s) => s, - Err(err) => bug!("failed to fully normalize {:?}: {:?}", impl1_def_id, err), + Err(err) => { + tcx.sess.delay_span_bug( + tcx.def_span(impl1_def_id), + format!("failed to fully normalize {:?}: {:?}", impl1_def_id, err), + ); + return false; + } }; // Attempt to prove that impl2 applies, given all of the above. @@ -317,7 +324,7 @@ fn negative_impl<'cx, 'tcx>( let (subject2, obligations) = impl_subject_and_oblig(selcx, impl_env, impl2_def_id, impl2_substs); - !equate(&infcx, impl_env, subject1, subject2, obligations) + !equate(&infcx, impl_env, subject1, subject2, obligations, impl1_def_id) }) } @@ -327,6 +334,7 @@ fn equate<'cx, 'tcx>( subject1: ImplSubject<'tcx>, subject2: ImplSubject<'tcx>, obligations: impl Iterator<Item = PredicateObligation<'tcx>>, + body_def_id: DefId, ) -> bool { // do the impls unify? If not, not disjoint. let Ok(InferOk { obligations: more_obligations, .. }) = @@ -340,7 +348,7 @@ fn equate<'cx, 'tcx>( let opt_failing_obligation = obligations .into_iter() .chain(more_obligations) - .find(|o| negative_impl_exists(selcx, impl_env, o)); + .find(|o| negative_impl_exists(selcx, o, body_def_id)); if let Some(failing_obligation) = opt_failing_obligation { debug!("overlap: obligation unsatisfiable {:?}", failing_obligation); @@ -354,18 +362,16 @@ fn equate<'cx, 'tcx>( #[instrument(level = "debug", skip(selcx))] fn negative_impl_exists<'cx, 'tcx>( selcx: &SelectionContext<'cx, 'tcx>, - param_env: ty::ParamEnv<'tcx>, o: &PredicateObligation<'tcx>, + body_def_id: DefId, ) -> bool { - let infcx = &selcx.infcx().fork(); - - if resolve_negative_obligation(infcx, param_env, o) { + if resolve_negative_obligation(selcx.infcx().fork(), o, body_def_id) { return true; } // Try to prove a negative obligation exists for super predicates - for o in util::elaborate_predicates(infcx.tcx, iter::once(o.predicate)) { - if resolve_negative_obligation(infcx, param_env, &o) { + for o in util::elaborate_predicates(selcx.tcx(), iter::once(o.predicate)) { + if resolve_negative_obligation(selcx.infcx().fork(), &o, body_def_id) { return true; } } @@ -375,9 +381,9 @@ fn negative_impl_exists<'cx, 'tcx>( #[instrument(level = "debug", skip(infcx))] fn resolve_negative_obligation<'cx, 'tcx>( - infcx: &InferCtxt<'cx, 'tcx>, - param_env: ty::ParamEnv<'tcx>, + infcx: InferCtxt<'cx, 'tcx>, o: &PredicateObligation<'tcx>, + body_def_id: DefId, ) -> bool { let tcx = infcx.tcx; @@ -385,17 +391,25 @@ fn resolve_negative_obligation<'cx, 'tcx>( return false; }; - let mut fulfillment_cx = <dyn TraitEngine<'tcx>>::new(infcx.tcx); - fulfillment_cx.register_predicate_obligation(infcx, o); - - let errors = fulfillment_cx.select_all_or_error(infcx); - - if !errors.is_empty() { + let param_env = o.param_env; + if !super::fully_solve_obligation(&infcx, o).is_empty() { return false; } - // FIXME -- also add "assumed to be well formed" types into the `outlives_env` - let outlives_env = OutlivesEnvironment::new(param_env); + let (body_id, body_def_id) = if let Some(body_def_id) = body_def_id.as_local() { + (tcx.hir().local_def_id_to_hir_id(body_def_id), body_def_id) + } else { + (CRATE_HIR_ID, CRATE_DEF_ID) + }; + + let ocx = ObligationCtxt::new(&infcx); + let wf_tys = ocx.assumed_wf_types(param_env, DUMMY_SP, body_def_id); + let outlives_env = OutlivesEnvironment::with_bounds( + param_env, + Some(&infcx), + infcx.implied_bounds_tys(param_env, body_id, wf_tys), + ); + infcx.process_registered_region_obligations(outlives_env.region_bound_pairs(), param_env); infcx.resolve_regions(&outlives_env).is_empty() @@ -404,12 +418,12 @@ fn resolve_negative_obligation<'cx, 'tcx>( pub fn trait_ref_is_knowable<'tcx>( tcx: TyCtxt<'tcx>, trait_ref: ty::TraitRef<'tcx>, -) -> Option<Conflict> { +) -> Result<(), Conflict> { debug!("trait_ref_is_knowable(trait_ref={:?})", trait_ref); if orphan_check_trait_ref(tcx, trait_ref, InCrate::Remote).is_ok() { // A downstream or cousin crate is allowed to implement some // substitution of this trait-ref. - return Some(Conflict::Downstream); + return Err(Conflict::Downstream); } if trait_ref_is_local_or_fundamental(tcx, trait_ref) { @@ -418,7 +432,7 @@ pub fn trait_ref_is_knowable<'tcx>( // allowed to implement a substitution of this trait ref, which // means impls could only come from dependencies of this crate, // which we already know about. - return None; + return Ok(()); } // This is a remote non-fundamental trait, so if another crate @@ -431,10 +445,10 @@ pub fn trait_ref_is_knowable<'tcx>( // we are an owner. if orphan_check_trait_ref(tcx, trait_ref, InCrate::Local).is_ok() { debug!("trait_ref_is_knowable: orphan check passed"); - None + Ok(()) } else { debug!("trait_ref_is_knowable: nonlocal, nonfundamental, unowned"); - Some(Conflict::Upstream) + Err(Conflict::Upstream) } } @@ -740,7 +754,21 @@ impl<'tcx> TypeVisitor<'tcx> for OrphanChecker<'tcx> { result } - // FIXME: Constants should participate in orphan checking. + /// All possible values for a constant parameter already exist + /// in the crate defining the trait, so they are always non-local[^1]. + /// + /// Because there's no way to have an impl where the first local + /// generic argument is a constant, we also don't have to fail + /// the orphan check when encountering a parameter or a generic constant. + /// + /// This means that we can completely ignore constants during the orphan check. + /// + /// See `src/test/ui/coherence/const-generics-orphan-check-ok.rs` for examples. + /// + /// [^1]: This might not hold for function pointers or trait objects in the future. + /// As these should be quite rare as const arguments and especially rare as impl + /// parameters, allowing uncovered const parameters in impls seems more useful + /// than allowing `impl<T> Trait<local_fn_ptr, T> for i32` to compile. fn visit_const(&mut self, _c: ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> { ControlFlow::CONTINUE } diff --git a/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs b/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs index 254bc4ab6..5a213987e 100644 --- a/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs +++ b/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs @@ -183,7 +183,7 @@ pub fn is_const_evaluatable<'cx, 'tcx>( FailureKind::Concrete => {} } } - let concrete = infcx.const_eval_resolve(param_env, uv.expand(), Some(span)); + let concrete = infcx.const_eval_resolve(param_env, uv, Some(span)); match concrete { Err(ErrorHandled::TooGeneric) => { Err(NotConstEvaluatable::Error(infcx.tcx.sess.delay_span_bug( @@ -210,7 +210,7 @@ pub fn is_const_evaluatable<'cx, 'tcx>( // and hopefully soon change this to an error. // // See #74595 for more details about this. - let concrete = infcx.const_eval_resolve(param_env, uv.expand(), Some(span)); + let concrete = infcx.const_eval_resolve(param_env, uv, Some(span)); match concrete { // If we're evaluating a foreign constant, under a nightly compiler without generic diff --git a/compiler/rustc_trait_selection/src/traits/engine.rs b/compiler/rustc_trait_selection/src/traits/engine.rs index 6c177f638..dba4d4f69 100644 --- a/compiler/rustc_trait_selection/src/traits/engine.rs +++ b/compiler/rustc_trait_selection/src/traits/engine.rs @@ -3,7 +3,8 @@ use std::cell::RefCell; use super::TraitEngine; use super::{ChalkFulfillmentContext, FulfillmentContext}; use crate::infer::InferCtxtExt; -use rustc_hir::def_id::DefId; +use rustc_data_structures::fx::FxHashSet; +use rustc_hir::def_id::{DefId, LocalDefId}; use rustc_infer::infer::{InferCtxt, InferOk}; use rustc_infer::traits::{ FulfillmentError, Obligation, ObligationCause, PredicateObligation, TraitEngineExt as _, @@ -12,9 +13,11 @@ use rustc_middle::ty::error::TypeError; use rustc_middle::ty::ToPredicate; use rustc_middle::ty::TypeFoldable; use rustc_middle::ty::{self, Ty, TyCtxt}; +use rustc_span::Span; pub trait TraitEngineExt<'tcx> { fn new(tcx: TyCtxt<'tcx>) -> Box<Self>; + fn new_in_snapshot(tcx: TyCtxt<'tcx>) -> Box<Self>; } impl<'tcx> TraitEngineExt<'tcx> for dyn TraitEngine<'tcx> { @@ -25,6 +28,14 @@ impl<'tcx> TraitEngineExt<'tcx> for dyn TraitEngine<'tcx> { Box::new(FulfillmentContext::new()) } } + + fn new_in_snapshot(tcx: TyCtxt<'tcx>) -> Box<Self> { + if tcx.sess.opts.unstable_opts.chalk { + Box::new(ChalkFulfillmentContext::new()) + } else { + Box::new(FulfillmentContext::new_in_snapshot()) + } + } } /// Used if you want to have pleasant experience when dealing @@ -39,6 +50,10 @@ impl<'a, 'tcx> ObligationCtxt<'a, 'tcx> { Self { infcx, engine: RefCell::new(<dyn TraitEngine<'_>>::new(infcx.tcx)) } } + pub fn new_in_snapshot(infcx: &'a InferCtxt<'a, 'tcx>) -> Self { + Self { infcx, engine: RefCell::new(<dyn TraitEngine<'_>>::new_in_snapshot(infcx.tcx)) } + } + pub fn register_obligation(&self, obligation: PredicateObligation<'tcx>) { self.engine.borrow_mut().register_predicate_obligation(self.infcx, obligation); } @@ -109,4 +124,34 @@ impl<'a, 'tcx> ObligationCtxt<'a, 'tcx> { pub fn select_all_or_error(&self) -> Vec<FulfillmentError<'tcx>> { self.engine.borrow_mut().select_all_or_error(self.infcx) } + + pub fn assumed_wf_types( + &self, + param_env: ty::ParamEnv<'tcx>, + span: Span, + def_id: LocalDefId, + ) -> FxHashSet<Ty<'tcx>> { + let tcx = self.infcx.tcx; + let assumed_wf_types = tcx.assumed_wf_types(def_id); + let mut implied_bounds = FxHashSet::default(); + let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); + let cause = ObligationCause::misc(span, hir_id); + for ty in assumed_wf_types { + // FIXME(@lcnr): rustc currently does not check wf for types + // pre-normalization, meaning that implied bounds are sometimes + // incorrect. See #100910 for more details. + // + // Not adding the unnormalized types here mostly fixes that, except + // that there are projections which are still ambiguous in the item definition + // but do normalize successfully when using the item, see #98543. + // + // Anyways, I will hopefully soon change implied bounds to make all of this + // sound and then uncomment this line again. + + // implied_bounds.insert(ty); + let normalized = self.normalize(cause.clone(), param_env, ty); + implied_bounds.insert(normalized); + } + implied_bounds + } } diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs index e442c5c91..efdb1ace1 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs @@ -22,6 +22,7 @@ use rustc_hir::intravisit::Visitor; use rustc_hir::GenericParam; use rustc_hir::Item; use rustc_hir::Node; +use rustc_infer::infer::TypeTrace; use rustc_infer::traits::TraitEngine; use rustc_middle::traits::select::OverflowError; use rustc_middle::ty::abstract_const::NotConstEvaluatable; @@ -348,7 +349,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { message, label, note, - enclosing_scope, + parent_label, append_const_msg, } = self.on_unimplemented_note(trait_ref, &obligation); let have_alt_message = message.is_some() || label.is_some(); @@ -449,12 +450,27 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { { "consider using `()`, or a `Result`".to_owned() } else { - format!( - "{}the trait `{}` is not implemented for `{}`", - pre_message, - trait_predicate.print_modifiers_and_trait_path(), - trait_ref.skip_binder().self_ty(), - ) + let ty_desc = match trait_ref.skip_binder().self_ty().kind() { + ty::FnDef(_, _) => Some("fn item"), + ty::Closure(_, _) => Some("closure"), + _ => None, + }; + + match ty_desc { + Some(desc) => format!( + "{}the trait `{}` is not implemented for {} `{}`", + pre_message, + trait_predicate.print_modifiers_and_trait_path(), + desc, + trait_ref.skip_binder().self_ty(), + ), + None => format!( + "{}the trait `{}` is not implemented for `{}`", + pre_message, + trait_predicate.print_modifiers_and_trait_path(), + trait_ref.skip_binder().self_ty(), + ), + } }; if self.suggest_add_reference_to_arg( @@ -514,7 +530,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { // If it has a custom `#[rustc_on_unimplemented]` note, let's display it err.note(s.as_str()); } - if let Some(ref s) = enclosing_scope { + if let Some(ref s) = parent_label { let body = tcx .hir() .opt_local_def_id(obligation.cause.body_id) @@ -523,11 +539,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { hir_id: obligation.cause.body_id, }) }); - - let enclosing_scope_span = - tcx.hir().span_with_body(tcx.hir().local_def_id_to_hir_id(body)); - - err.span_label(enclosing_scope_span, s); + err.span_label(tcx.def_span(body), s); } self.suggest_floating_point_literal(&obligation, &mut err, &trait_ref); @@ -859,8 +871,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { } } - err.emit(); - return; + err } ty::PredicateKind::WellFormed(ty) => { @@ -941,9 +952,14 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { self.reported_closure_mismatch.borrow_mut().insert((span, found_span)); + let mut not_tupled = false; + let found = match found_trait_ref.skip_binder().substs.type_at(1).kind() { ty::Tuple(ref tys) => vec![ArgKind::empty(); tys.len()], - _ => vec![ArgKind::empty()], + _ => { + not_tupled = true; + vec![ArgKind::empty()] + } }; let expected_ty = expected_trait_ref.skip_binder().substs.type_at(1); @@ -951,10 +967,28 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { ty::Tuple(ref tys) => { tys.iter().map(|t| ArgKind::from_expected_ty(t, Some(span))).collect() } - _ => vec![ArgKind::Arg("_".to_owned(), expected_ty.to_string())], + _ => { + not_tupled = true; + vec![ArgKind::Arg("_".to_owned(), expected_ty.to_string())] + } }; - if found.len() == expected.len() { + // If this is a `Fn` family trait and either the expected or found + // is not tupled, then fall back to just a regular mismatch error. + // This shouldn't be common unless manually implementing one of the + // traits manually, but don't make it more confusing when it does + // happen. + if Some(expected_trait_ref.def_id()) != tcx.lang_items().gen_trait() && not_tupled { + self.report_and_explain_type_error( + TypeTrace::poly_trait_refs( + &obligation.cause, + true, + expected_trait_ref, + found_trait_ref, + ), + ty::error::TypeError::Mismatch, + ) + } else if found.len() == expected.len() { self.report_closure_arg_mismatch( span, found_span, @@ -1315,6 +1349,13 @@ trait InferCtxtPrivExt<'hir, 'tcx> { error: &MismatchedProjectionTypes<'tcx>, ); + fn maybe_detailed_projection_msg( + &self, + pred: ty::ProjectionPredicate<'tcx>, + normalized_ty: ty::Term<'tcx>, + expected_ty: ty::Term<'tcx>, + ) -> Option<String>; + fn fuzzy_match_tys( &self, a: Ty<'tcx>, @@ -1476,13 +1517,28 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> { .emit(); } FulfillmentErrorCode::CodeConstEquateError(ref expected_found, ref err) => { - self.report_mismatched_consts( + let mut diag = self.report_mismatched_consts( &error.obligation.cause, expected_found.expected, expected_found.found, err.clone(), - ) - .emit(); + ); + let code = error.obligation.cause.code().peel_derives().peel_match_impls(); + if let ObligationCauseCode::BindingObligation(..) + | ObligationCauseCode::ItemObligation(..) + | ObligationCauseCode::ExprBindingObligation(..) + | ObligationCauseCode::ExprItemObligation(..) = code + { + self.note_obligation_cause_code( + &mut diag, + &error.obligation.predicate, + error.obligation.param_env, + code, + &mut vec![], + &mut Default::default(), + ); + } + diag.emit(); } } } @@ -1500,8 +1556,7 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> { } self.probe(|_| { - let err_buf; - let mut err = &error.err; + let mut err = error.err; let mut values = None; // try to find the mismatched types to report the error with. @@ -1534,31 +1589,28 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> { obligation.cause.code().peel_derives(), ObligationCauseCode::ItemObligation(_) | ObligationCauseCode::BindingObligation(_, _) + | ObligationCauseCode::ExprItemObligation(..) + | ObligationCauseCode::ExprBindingObligation(..) | ObligationCauseCode::ObjectCastObligation(..) | ObligationCauseCode::OpaqueType ); - if let Err(error) = self.at(&obligation.cause, obligation.param_env).eq_exp( + if let Err(new_err) = self.at(&obligation.cause, obligation.param_env).eq_exp( is_normalized_ty_expected, normalized_ty, data.term, ) { - values = Some(infer::ValuePairs::Terms(ExpectedFound::new( - is_normalized_ty_expected, - normalized_ty, - data.term, - ))); - err_buf = error; - err = &err_buf; + values = Some((data, is_normalized_ty_expected, normalized_ty, data.term)); + err = new_err; } } - let mut diag = struct_span_err!( - self.tcx.sess, - obligation.cause.span, - E0271, - "type mismatch resolving `{}`", - predicate - ); + let msg = values + .and_then(|(predicate, _, normalized_ty, expected_ty)| { + self.maybe_detailed_projection_msg(predicate, normalized_ty, expected_ty) + }) + .unwrap_or_else(|| format!("type mismatch resolving `{}`", predicate)); + let mut diag = struct_span_err!(self.tcx.sess, obligation.cause.span, E0271, "{msg}"); + let secondary_span = match predicate.kind().skip_binder() { ty::PredicateKind::Projection(proj) => self .tcx @@ -1596,7 +1648,13 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> { &mut diag, &obligation.cause, secondary_span, - values, + values.map(|(_, is_normalized_ty_expected, normalized_ty, term)| { + infer::ValuePairs::Terms(ExpectedFound::new( + is_normalized_ty_expected, + normalized_ty, + term, + )) + }), err, true, false, @@ -1606,6 +1664,33 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> { }); } + fn maybe_detailed_projection_msg( + &self, + pred: ty::ProjectionPredicate<'tcx>, + normalized_ty: ty::Term<'tcx>, + expected_ty: ty::Term<'tcx>, + ) -> Option<String> { + let trait_def_id = pred.projection_ty.trait_def_id(self.tcx); + let self_ty = pred.projection_ty.self_ty(); + + if Some(pred.projection_ty.item_def_id) == self.tcx.lang_items().fn_once_output() { + Some(format!( + "expected `{self_ty}` to be a {fn_kind} that returns `{expected_ty}`, but it returns `{normalized_ty}`", + fn_kind = self_ty.prefix_string(self.tcx) + )) + } else if Some(trait_def_id) == self.tcx.lang_items().future_trait() { + Some(format!( + "expected `{self_ty}` to be a future that resolves to `{expected_ty}`, but it resolves to `{normalized_ty}`" + )) + } else if Some(trait_def_id) == self.tcx.get_diagnostic_item(sym::Iterator) { + Some(format!( + "expected `{self_ty}` to be an iterator that yields `{expected_ty}`, but it yields `{normalized_ty}`" + )) + } else { + None + } + } + fn fuzzy_match_tys( &self, mut a: Ty<'tcx>, @@ -1731,13 +1816,21 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> { return false; } if candidates.len() == 1 { + let ty_desc = match candidates[0].self_ty().kind() { + ty::FnPtr(_) => Some("fn pointer"), + _ => None, + }; + let the_desc = match ty_desc { + Some(desc) => format!(" implemented for {} `", desc), + None => " implemented for `".to_string(), + }; err.highlighted_help(vec![ ( format!("the trait `{}` ", candidates[0].print_only_trait_path()), Style::NoStyle, ), ("is".to_string(), Style::Highlight), - (" implemented for `".to_string(), Style::NoStyle), + (the_desc, Style::NoStyle), (candidates[0].self_ty().to_string(), Style::Highlight), ("`".to_string(), Style::NoStyle), ]); @@ -1802,9 +1895,7 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> { // FIXME(compiler-errors): This could be generalized, both to // be more granular, and probably look past other `#[fundamental]` // types, too. - self.tcx - .visibility(def.did()) - .is_accessible_from(body_id.owner.to_def_id(), self.tcx) + self.tcx.visibility(def.did()).is_accessible_from(body_id.owner, self.tcx) } else { true } @@ -1940,7 +2031,7 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> { let predicate = self.resolve_vars_if_possible(obligation.predicate); let span = obligation.cause.span; - debug!(?predicate, obligation.cause.code = tracing::field::debug(&obligation.cause.code())); + debug!(?predicate, obligation.cause.code = ?obligation.cause.code()); // Ambiguity errors are often caused as fallout from earlier errors. // We ignore them if this `infcx` is tainted in some cases below. @@ -2033,13 +2124,11 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> { } } - if let ObligationCauseCode::ItemObligation(def_id) = *obligation.cause.code() { + if let ObligationCauseCode::ItemObligation(def_id) | ObligationCauseCode::ExprItemObligation(def_id, ..) = *obligation.cause.code() { self.suggest_fully_qualified_path(&mut err, def_id, span, trait_ref.def_id()); - } else if let ( - Ok(ref snippet), - &ObligationCauseCode::BindingObligation(def_id, _), - ) = - (self.tcx.sess.source_map().span_to_snippet(span), obligation.cause.code()) + } else if let Ok(snippet) = &self.tcx.sess.source_map().span_to_snippet(span) + && let ObligationCauseCode::BindingObligation(def_id, _) | ObligationCauseCode::ExprBindingObligation(def_id, ..) + = *obligation.cause.code() { let generics = self.tcx.generics_of(def_id); if generics.params.iter().any(|p| p.name != kw::SelfUpper) @@ -2119,12 +2208,12 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> { && let [ .., trait_path_segment @ hir::PathSegment { - res: Some(rustc_hir::def::Res::Def(rustc_hir::def::DefKind::Trait, trait_id)), + res: rustc_hir::def::Res::Def(rustc_hir::def::DefKind::Trait, trait_id), .. }, hir::PathSegment { ident: assoc_item_name, - res: Some(rustc_hir::def::Res::Def(_, item_id)), + res: rustc_hir::def::Res::Def(_, item_id), .. } ] = path.segments @@ -2462,15 +2551,10 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> { err: &mut Diagnostic, obligation: &PredicateObligation<'tcx>, ) { - let ( - ty::PredicateKind::Trait(pred), - &ObligationCauseCode::BindingObligation(item_def_id, span), - ) = ( - obligation.predicate.kind().skip_binder(), - obligation.cause.code().peel_derives(), - ) else { - return; - }; + let ty::PredicateKind::Trait(pred) = obligation.predicate.kind().skip_binder() else { return; }; + let (ObligationCauseCode::BindingObligation(item_def_id, span) + | ObligationCauseCode::ExprBindingObligation(item_def_id, span, ..)) + = *obligation.cause.code().peel_derives() else { return; }; debug!(?pred, ?item_def_id, ?span); let (Some(node), true) = ( 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 e6907637c..e11a42201 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 @@ -143,7 +143,9 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { } if let ObligationCauseCode::ItemObligation(item) - | ObligationCauseCode::BindingObligation(item, _) = *obligation.cause.code() + | ObligationCauseCode::BindingObligation(item, _) + | ObligationCauseCode::ExprItemObligation(item, ..) + | ObligationCauseCode::ExprBindingObligation(item, ..) = *obligation.cause.code() { // FIXME: maybe also have some way of handling methods // from other traits? That would require name resolution, @@ -254,7 +256,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { } } } - if let ty::Dynamic(traits, _) = self_ty.kind() { + if let ty::Dynamic(traits, _, _) = self_ty.kind() { for t in traits.iter() { if let ty::ExistentialPredicate::Trait(trait_ref) = t.skip_binder() { flags.push((sym::_Self, Some(self.tcx.def_path_str(trait_ref.def_id)))) 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 219413121..13d9c1600 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs @@ -20,13 +20,12 @@ use rustc_hir::def_id::DefId; use rustc_hir::intravisit::Visitor; use rustc_hir::lang_items::LangItem; use rustc_hir::{AsyncGeneratorKind, GeneratorKind, Node}; -use rustc_infer::infer::TyCtxtInferExt; +use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind}; use rustc_middle::hir::map; use rustc_middle::ty::{ self, suggest_arbitrary_trait_bound, suggest_constraining_type_param, AdtKind, DefIdTree, GeneratorDiagnosticData, GeneratorInteriorTypeCause, Infer, InferTy, IsSuggestable, - ProjectionPredicate, ToPredicate, Ty, TyCtxt, TypeFoldable, TypeFolder, TypeSuperFoldable, - TypeVisitable, + ToPredicate, Ty, TyCtxt, TypeFoldable, TypeFolder, TypeSuperFoldable, TypeVisitable, }; use rustc_middle::ty::{TypeAndMut, TypeckResults}; use rustc_session::Limit; @@ -174,7 +173,7 @@ pub trait InferCtxtExt<'tcx> { &self, err: &mut Diagnostic, trait_pred: ty::PolyTraitPredicate<'tcx>, - proj_pred: Option<ty::PolyProjectionPredicate<'tcx>>, + associated_item: Option<(&'static str, Ty<'tcx>)>, body_id: hir::HirId, ); @@ -467,7 +466,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { &self, mut err: &mut Diagnostic, trait_pred: ty::PolyTraitPredicate<'tcx>, - proj_pred: Option<ty::PolyProjectionPredicate<'tcx>>, + associated_ty: Option<(&'static str, Ty<'tcx>)>, body_id: hir::HirId, ) { let trait_pred = self.resolve_numeric_literals_with_default(trait_pred); @@ -604,21 +603,18 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { trait_pred.print_modifiers_and_trait_path().to_string() ); - if let Some(proj_pred) = proj_pred { - let ProjectionPredicate { projection_ty, term } = proj_pred.skip_binder(); - let item = self.tcx.associated_item(projection_ty.item_def_id); - + if let Some((name, term)) = associated_ty { // FIXME: this case overlaps with code in TyCtxt::note_and_explain_type_err. // That should be extracted into a helper function. if constraint.ends_with('>') { constraint = format!( - "{}, {}={}>", + "{}, {} = {}>", &constraint[..constraint.len() - 1], - item.name, + name, term ); } else { - constraint.push_str(&format!("<{}={}>", item.name, term)); + constraint.push_str(&format!("<{} = {}>", name, term)); } } @@ -648,7 +644,13 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { .. }) if !param_ty => { // Missing generic type parameter bound. - if suggest_arbitrary_trait_bound(self.tcx, generics, &mut err, trait_pred) { + if suggest_arbitrary_trait_bound( + self.tcx, + generics, + &mut err, + trait_pred, + associated_ty, + ) { return; } } @@ -671,11 +673,16 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { trait_pred: ty::PolyTraitPredicate<'tcx>, ) -> bool { // It only make sense when suggesting dereferences for arguments - let ObligationCauseCode::FunctionArgumentObligation { .. } = obligation.cause.code() else { - return false; - }; - let param_env = obligation.param_env; - let body_id = obligation.cause.body_id; + let ObligationCauseCode::FunctionArgumentObligation { arg_hir_id, .. } = obligation.cause.code() + else { return false; }; + let Some(typeck_results) = self.in_progress_typeck_results + else { return false; }; + let typeck_results = typeck_results.borrow(); + let hir::Node::Expr(expr) = self.tcx.hir().get(*arg_hir_id) + else { return false; }; + let Some(arg_ty) = typeck_results.expr_ty_adjusted_opt(expr) + else { return false; }; + let span = obligation.cause.span; let mut real_trait_pred = trait_pred; let mut code = obligation.cause.code(); @@ -685,11 +692,25 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { real_trait_pred = parent_trait_pred; } - // Skipping binder here, remapping below - let real_ty = real_trait_pred.self_ty().skip_binder(); + let real_ty = real_trait_pred.self_ty(); + // We `erase_late_bound_regions` here because `make_subregion` does not handle + // `ReLateBound`, and we don't particularly care about the regions. + if self + .can_eq(obligation.param_env, self.tcx.erase_late_bound_regions(real_ty), arg_ty) + .is_err() + { + continue; + } - if let ty::Ref(region, base_ty, mutbl) = *real_ty.kind() { - let mut autoderef = Autoderef::new(self, param_env, body_id, span, base_ty, span); + if let ty::Ref(region, base_ty, mutbl) = *real_ty.skip_binder().kind() { + let mut autoderef = Autoderef::new( + self, + obligation.param_env, + obligation.cause.body_id, + span, + base_ty, + span, + ); if let Some(steps) = autoderef.find_map(|(ty, steps)| { // Re-add the `&` let ty = self.tcx.mk_ref(region, TypeAndMut { ty, mutbl }); @@ -697,24 +718,29 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { // Remapping bound vars here let real_trait_pred_and_ty = real_trait_pred.map_bound(|inner_trait_pred| (inner_trait_pred, ty)); - let obligation = self - .mk_trait_obligation_with_new_self_ty(param_env, real_trait_pred_and_ty); + let obligation = self.mk_trait_obligation_with_new_self_ty( + obligation.param_env, + real_trait_pred_and_ty, + ); Some(steps).filter(|_| self.predicate_may_hold(&obligation)) }) { if steps > 0 { - if let Ok(src) = self.tcx.sess.source_map().span_to_snippet(span) { - // Don't care about `&mut` because `DerefMut` is used less - // often and user will not expect autoderef happens. - if src.starts_with('&') && !src.starts_with("&mut ") { - let derefs = "*".repeat(steps); - err.span_suggestion( - span, - "consider dereferencing here", - format!("&{}{}", derefs, &src[1..]), - Applicability::MachineApplicable, - ); - return true; - } + // Don't care about `&mut` because `DerefMut` is used less + // often and user will not expect autoderef happens. + if let Some(hir::Node::Expr(hir::Expr { + kind: + hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Not, expr), + .. + })) = self.tcx.hir().find(*arg_hir_id) + { + let derefs = "*".repeat(steps); + err.span_suggestion_verbose( + expr.span.shrink_to_lo(), + "consider dereferencing here", + derefs, + Applicability::MachineApplicable, + ); + return true; } } } else if real_trait_pred != trait_pred { @@ -724,7 +750,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { let real_trait_pred_and_base_ty = real_trait_pred.map_bound(|inner_trait_pred| (inner_trait_pred, base_ty)); let obligation = self.mk_trait_obligation_with_new_self_ty( - param_env, + obligation.param_env, real_trait_pred_and_base_ty, ); if self.predicate_may_hold(&obligation) { @@ -750,7 +776,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { // Get the local name of this closure. This can be inaccurate because // of the possibility of reassignment, but this should be good enough. match &kind { - hir::PatKind::Binding(hir::BindingAnnotation::Unannotated, _, ident, None) => { + hir::PatKind::Binding(hir::BindingAnnotation::NONE, _, ident, None) => { Some(ident.name) } _ => { @@ -852,6 +878,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { _ => return false, }; if matches!(obligation.cause.code(), ObligationCauseCode::FunctionArgumentObligation { .. }) + && obligation.cause.span.can_be_used_for_suggestions() { // When the obligation error has been ensured to have been caused by // an argument, the `obligation.cause.span` points at the expression @@ -882,6 +909,10 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { obligation.cause.code() { &parent_code + } else if let ObligationCauseCode::ItemObligation(_) + | ObligationCauseCode::ExprItemObligation(..) = obligation.cause.code() + { + obligation.cause.code() } else if let ExpnKind::Desugaring(DesugaringKind::ForLoop) = span.ctxt().outer_expn_data().kind { @@ -906,102 +937,121 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { let param_env = obligation.param_env; // Try to apply the original trait binding obligation by borrowing. - let mut try_borrowing = - |old_pred: ty::PolyTraitPredicate<'tcx>, blacklist: &[DefId]| -> bool { - if blacklist.contains(&old_pred.def_id()) { - return false; - } - // We map bounds to `&T` and `&mut T` - let trait_pred_and_imm_ref = old_pred.map_bound(|trait_pred| { - ( - trait_pred, - self.tcx.mk_imm_ref(self.tcx.lifetimes.re_static, trait_pred.self_ty()), - ) - }); - let trait_pred_and_mut_ref = old_pred.map_bound(|trait_pred| { + let mut try_borrowing = |old_pred: ty::PolyTraitPredicate<'tcx>, + blacklist: &[DefId]| + -> bool { + if blacklist.contains(&old_pred.def_id()) { + return false; + } + // We map bounds to `&T` and `&mut T` + let trait_pred_and_imm_ref = old_pred.map_bound(|trait_pred| { + ( + trait_pred, + self.tcx.mk_imm_ref(self.tcx.lifetimes.re_static, trait_pred.self_ty()), + ) + }); + let trait_pred_and_mut_ref = old_pred.map_bound(|trait_pred| { + ( + trait_pred, + self.tcx.mk_mut_ref(self.tcx.lifetimes.re_static, trait_pred.self_ty()), + ) + }); + + let mk_result = |trait_pred_and_new_ty| { + let obligation = + self.mk_trait_obligation_with_new_self_ty(param_env, trait_pred_and_new_ty); + self.predicate_must_hold_modulo_regions(&obligation) + }; + let imm_ref_self_ty_satisfies_pred = mk_result(trait_pred_and_imm_ref); + let mut_ref_self_ty_satisfies_pred = mk_result(trait_pred_and_mut_ref); + + let (ref_inner_ty_satisfies_pred, ref_inner_ty_mut) = + if let ObligationCauseCode::ItemObligation(_) | ObligationCauseCode::ExprItemObligation(..) = obligation.cause.code() + && let ty::Ref(_, ty, mutability) = old_pred.self_ty().skip_binder().kind() + { ( - trait_pred, - self.tcx.mk_mut_ref(self.tcx.lifetimes.re_static, trait_pred.self_ty()), + mk_result(old_pred.map_bound(|trait_pred| (trait_pred, *ty))), + matches!(mutability, hir::Mutability::Mut), ) - }); - - let mk_result = |trait_pred_and_new_ty| { - let obligation = - self.mk_trait_obligation_with_new_self_ty(param_env, trait_pred_and_new_ty); - self.predicate_must_hold_modulo_regions(&obligation) + } else { + (false, false) }; - let imm_result = mk_result(trait_pred_and_imm_ref); - let mut_result = mk_result(trait_pred_and_mut_ref); - - if imm_result || mut_result { - if let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(span) { - // We have a very specific type of error, where just borrowing this argument - // might solve the problem. In cases like this, the important part is the - // original type obligation, not the last one that failed, which is arbitrary. - // Because of this, we modify the error to refer to the original obligation and - // return early in the caller. - - let msg = format!("the trait bound `{}` is not satisfied", old_pred); - if has_custom_message { - err.note(&msg); - } else { - err.message = - vec![(rustc_errors::DiagnosticMessage::Str(msg), Style::NoStyle)]; - } - if snippet.starts_with('&') { - // This is already a literal borrow and the obligation is failing - // somewhere else in the obligation chain. Do not suggest non-sense. - return false; - } - err.span_label( - span, + + if imm_ref_self_ty_satisfies_pred + || mut_ref_self_ty_satisfies_pred + || ref_inner_ty_satisfies_pred + { + if let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(span) { + // We don't want a borrowing suggestion on the fields in structs, + // ``` + // struct Foo { + // the_foos: Vec<Foo> + // } + // ``` + if !matches!( + span.ctxt().outer_expn_data().kind, + ExpnKind::Root | ExpnKind::Desugaring(DesugaringKind::ForLoop) + ) { + return false; + } + if snippet.starts_with('&') { + // This is already a literal borrow and the obligation is failing + // somewhere else in the obligation chain. Do not suggest non-sense. + return false; + } + // We have a very specific type of error, where just borrowing this argument + // might solve the problem. In cases like this, the important part is the + // original type obligation, not the last one that failed, which is arbitrary. + // Because of this, we modify the error to refer to the original obligation and + // return early in the caller. + + let msg = format!("the trait bound `{}` is not satisfied", old_pred); + if has_custom_message { + err.note(&msg); + } else { + err.message = + vec![(rustc_errors::DiagnosticMessage::Str(msg), Style::NoStyle)]; + } + err.span_label( + span, + format!( + "the trait `{}` is not implemented for `{}`", + old_pred.print_modifiers_and_trait_path(), + old_pred.self_ty().skip_binder(), + ), + ); + + if imm_ref_self_ty_satisfies_pred && mut_ref_self_ty_satisfies_pred { + err.span_suggestions( + span.shrink_to_lo(), + "consider borrowing here", + ["&".to_string(), "&mut ".to_string()].into_iter(), + Applicability::MaybeIncorrect, + ); + } else { + let is_mut = mut_ref_self_ty_satisfies_pred || ref_inner_ty_mut; + err.span_suggestion_verbose( + span.shrink_to_lo(), &format!( - "expected an implementor of trait `{}`", - old_pred.print_modifiers_and_trait_path(), + "consider{} borrowing here", + if is_mut { " mutably" } else { "" } ), + format!("&{}", if is_mut { "mut " } else { "" }), + Applicability::MaybeIncorrect, ); - - // This if is to prevent a special edge-case - if matches!( - span.ctxt().outer_expn_data().kind, - ExpnKind::Root | ExpnKind::Desugaring(DesugaringKind::ForLoop) - ) { - // We don't want a borrowing suggestion on the fields in structs, - // ``` - // struct Foo { - // the_foos: Vec<Foo> - // } - // ``` - - if imm_result && mut_result { - err.span_suggestions( - span.shrink_to_lo(), - "consider borrowing here", - ["&".to_string(), "&mut ".to_string()].into_iter(), - Applicability::MaybeIncorrect, - ); - } else { - err.span_suggestion_verbose( - span.shrink_to_lo(), - &format!( - "consider{} borrowing here", - if mut_result { " mutably" } else { "" } - ), - format!("&{}", if mut_result { "mut " } else { "" }), - Applicability::MaybeIncorrect, - ); - } - } - return true; } + return true; } - return false; - }; + } + return false; + }; if let ObligationCauseCode::ImplDerivedObligation(cause) = &*code { try_borrowing(cause.derived.parent_trait_pred, &[]) } else if let ObligationCauseCode::BindingObligation(_, _) - | ObligationCauseCode::ItemObligation(_) = code + | ObligationCauseCode::ItemObligation(_) + | ObligationCauseCode::ExprItemObligation(..) + | ObligationCauseCode::ExprBindingObligation(..) = code { try_borrowing(poly_trait_pred, &never_suggest_borrow) } else { @@ -1017,7 +1067,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { self_ty: Ty<'tcx>, object_ty: Ty<'tcx>, ) { - let ty::Dynamic(predicates, _) = object_ty.kind() else { return; }; + let ty::Dynamic(predicates, _, ty::Dyn) = object_ty.kind() else { return; }; let self_ref_ty = self.tcx.mk_imm_ref(self.tcx.lifetimes.re_erased, self_ty); for predicate in predicates.iter() { @@ -1110,8 +1160,8 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { // and if not maybe suggest doing something else? If we kept the expression around we // could also check if it is an fn call (very likely) and suggest changing *that*, if // it is from the local crate. - err.span_suggestion_verbose( - expr.span.shrink_to_hi().with_hi(span.hi()), + err.span_suggestion( + span, "remove the `.await`", "", Applicability::MachineApplicable, @@ -1315,7 +1365,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { let trait_pred = self.resolve_vars_if_possible(trait_pred); let ty = trait_pred.skip_binder().self_ty(); let is_object_safe = match ty.kind() { - ty::Dynamic(predicates, _) => { + ty::Dynamic(predicates, _, ty::Dyn) => { // If the `dyn Trait` is not object safe, do not suggest `Box<dyn Trait>`. predicates .principal_def_id() @@ -1375,7 +1425,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { let mut spans_and_needs_box = vec![]; match liberated_sig.output().kind() { - ty::Dynamic(predicates, _) => { + ty::Dynamic(predicates, _, _) => { let cause = ObligationCause::misc(ret_ty.span, fn_hir_id); let param_env = ty::ParamEnv::empty(); @@ -1541,32 +1591,38 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { expected: ty::PolyTraitRef<'tcx>, ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> { pub(crate) fn build_fn_sig_ty<'tcx>( - tcx: TyCtxt<'tcx>, + infcx: &InferCtxt<'_, 'tcx>, trait_ref: ty::PolyTraitRef<'tcx>, ) -> Ty<'tcx> { let inputs = trait_ref.skip_binder().substs.type_at(1); let sig = match inputs.kind() { ty::Tuple(inputs) - if tcx.fn_trait_kind_from_lang_item(trait_ref.def_id()).is_some() => + if infcx.tcx.fn_trait_kind_from_lang_item(trait_ref.def_id()).is_some() => { - tcx.mk_fn_sig( + infcx.tcx.mk_fn_sig( inputs.iter(), - tcx.mk_ty_infer(ty::TyVar(ty::TyVid::from_u32(0))), + infcx.next_ty_var(TypeVariableOrigin { + span: DUMMY_SP, + kind: TypeVariableOriginKind::MiscVariable, + }), false, hir::Unsafety::Normal, abi::Abi::Rust, ) } - _ => tcx.mk_fn_sig( + _ => infcx.tcx.mk_fn_sig( std::iter::once(inputs), - tcx.mk_ty_infer(ty::TyVar(ty::TyVid::from_u32(0))), + infcx.next_ty_var(TypeVariableOrigin { + span: DUMMY_SP, + kind: TypeVariableOriginKind::MiscVariable, + }), false, hir::Unsafety::Normal, abi::Abi::Rust, ), }; - tcx.mk_fn_ptr(trait_ref.rebind(sig)) + infcx.tcx.mk_fn_ptr(trait_ref.rebind(sig)) } let argument_kind = match expected.skip_binder().self_ty().kind() { @@ -1586,11 +1642,10 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { let found_span = found_span.unwrap_or(span); err.span_label(found_span, "found signature defined here"); - let expected = build_fn_sig_ty(self.tcx, expected); - let found = build_fn_sig_ty(self.tcx, found); + let expected = build_fn_sig_ty(self, expected); + let found = build_fn_sig_ty(self, found); - let (expected_str, found_str) = - self.tcx.infer_ctxt().enter(|infcx| infcx.cmp(expected, found)); + let (expected_str, found_str) = self.cmp(expected, found); let signature_kind = format!("{argument_kind} signature"); err.note_expected_found(&signature_kind, expected_str, &signature_kind, found_str); @@ -2201,7 +2256,8 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { | ObligationCauseCode::QuestionMark | ObligationCauseCode::CheckAssociatedTypeBounds { .. } | ObligationCauseCode::LetElse - | ObligationCauseCode::BinOp { .. } => {} + | ObligationCauseCode::BinOp { .. } + | ObligationCauseCode::AscribeUserTypeProvePredicate(..) => {} ObligationCauseCode::SliceOrArrayElem => { err.note("slice and array elements must have `Sized` type"); } @@ -2223,11 +2279,13 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { region, object_ty, )); } - ObligationCauseCode::ItemObligation(_item_def_id) => { + ObligationCauseCode::ItemObligation(_) + | ObligationCauseCode::ExprItemObligation(..) => { // We hold the `DefId` of the item introducing the obligation, but displaying it // doesn't add user usable information. It always point at an associated item. } - ObligationCauseCode::BindingObligation(item_def_id, span) => { + ObligationCauseCode::BindingObligation(item_def_id, span) + | ObligationCauseCode::ExprBindingObligation(item_def_id, span, ..) => { let item_name = tcx.def_path_str(item_def_id); let mut multispan = MultiSpan::from(span); if let Some(ident) = tcx.opt_item_ident(item_def_id) { @@ -2537,9 +2595,9 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { parent_trait_pred.remap_constness_diag(param_env); let parent_def_id = parent_trait_pred.def_id(); let msg = format!( - "required because of the requirements on the impl of `{}` for `{}`", - parent_trait_pred.print_modifiers_and_trait_path(), - parent_trait_pred.skip_binder().self_ty() + "required for `{}` to implement `{}`", + parent_trait_pred.skip_binder().self_ty(), + parent_trait_pred.print_modifiers_and_trait_path() ); let mut is_auto_trait = false; match self.tcx.hir().get_if_local(data.impl_def_id) { @@ -2608,9 +2666,9 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { pluralize!(count) )); err.note(&format!( - "required because of the requirements on the impl of `{}` for `{}`", - parent_trait_pred.print_modifiers_and_trait_path(), - parent_trait_pred.skip_binder().self_ty() + "required for `{}` to implement `{}`", + parent_trait_pred.skip_binder().self_ty(), + parent_trait_pred.print_modifiers_and_trait_path() )); } // #74711: avoid a stack overflow diff --git a/compiler/rustc_trait_selection/src/traits/fulfill.rs b/compiler/rustc_trait_selection/src/traits/fulfill.rs index 556ef466c..a81fef60a 100644 --- a/compiler/rustc_trait_selection/src/traits/fulfill.rs +++ b/compiler/rustc_trait_selection/src/traits/fulfill.rs @@ -135,7 +135,7 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentContext<'tcx> { /// `SomeTrait` or a where-clause that lets us unify `$0` with /// something concrete. If this fails, we'll unify `$0` with /// `projection_ty` again. - #[tracing::instrument(level = "debug", skip(self, infcx, param_env, cause))] + #[instrument(level = "debug", skip(self, infcx, param_env, cause))] fn normalize_projection_type( &mut self, infcx: &InferCtxt<'_, 'tcx>, @@ -427,16 +427,14 @@ impl<'a, 'b, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'b, 'tcx> { obligation.param_env, Binder::dummy(subtype), ) { - None => { + Err((a, b)) => { // None means that both are unresolved. - pending_obligation.stalled_on = vec![ - TyOrConstInferVar::maybe_from_ty(subtype.a).unwrap(), - TyOrConstInferVar::maybe_from_ty(subtype.b).unwrap(), - ]; + pending_obligation.stalled_on = + vec![TyOrConstInferVar::Ty(a), TyOrConstInferVar::Ty(b)]; ProcessResult::Unchanged } - Some(Ok(ok)) => ProcessResult::Changed(mk_pending(ok.obligations)), - Some(Err(err)) => { + Ok(Ok(ok)) => ProcessResult::Changed(mk_pending(ok.obligations)), + Ok(Err(err)) => { let expected_found = ExpectedFound::new(subtype.a_is_expected, subtype.a, subtype.b); ProcessResult::Error(FulfillmentErrorCode::CodeSubtypeError( @@ -453,16 +451,14 @@ impl<'a, 'b, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'b, 'tcx> { obligation.param_env, Binder::dummy(coerce), ) { - None => { + Err((a, b)) => { // None means that both are unresolved. - pending_obligation.stalled_on = vec![ - TyOrConstInferVar::maybe_from_ty(coerce.a).unwrap(), - TyOrConstInferVar::maybe_from_ty(coerce.b).unwrap(), - ]; + pending_obligation.stalled_on = + vec![TyOrConstInferVar::Ty(a), TyOrConstInferVar::Ty(b)]; ProcessResult::Unchanged } - Some(Ok(ok)) => ProcessResult::Changed(mk_pending(ok.obligations)), - Some(Err(err)) => { + Ok(Ok(ok)) => ProcessResult::Changed(mk_pending(ok.obligations)), + Ok(Err(err)) => { let expected_found = ExpectedFound::new(false, coerce.a, coerce.b); ProcessResult::Error(FulfillmentErrorCode::CodeSubtypeError( expected_found, @@ -509,11 +505,7 @@ impl<'a, 'b, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'b, 'tcx> { if let (ty::ConstKind::Unevaluated(a), ty::ConstKind::Unevaluated(b)) = (c1.kind(), c2.kind()) { - if infcx.try_unify_abstract_consts( - a.shrink(), - b.shrink(), - obligation.param_env, - ) { + if infcx.try_unify_abstract_consts(a, b, obligation.param_env) { return ProcessResult::Changed(vec![]); } } @@ -597,6 +589,7 @@ impl<'a, 'b, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'b, 'tcx> { } } + #[inline(never)] fn process_backedge<'c, I>( &mut self, cycle: I, diff --git a/compiler/rustc_trait_selection/src/traits/misc.rs b/compiler/rustc_trait_selection/src/traits/misc.rs index dd2769c71..e1bd48ba8 100644 --- a/compiler/rustc_trait_selection/src/traits/misc.rs +++ b/compiler/rustc_trait_selection/src/traits/misc.rs @@ -63,8 +63,7 @@ pub fn can_type_implement_copy<'tcx>( } else { ObligationCause::dummy_with_span(span) }; - let ctx = traits::FulfillmentContext::new(); - match traits::fully_normalize(&infcx, ctx, cause, param_env, ty) { + match traits::fully_normalize(&infcx, cause, param_env, ty) { Ok(ty) => { if !infcx.type_is_copy_modulo_regions(param_env, ty, span) { infringing.push((field, ty)); diff --git a/compiler/rustc_trait_selection/src/traits/mod.rs b/compiler/rustc_trait_selection/src/traits/mod.rs index 9c6bb0731..40596078f 100644 --- a/compiler/rustc_trait_selection/src/traits/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/mod.rs @@ -13,6 +13,7 @@ mod fulfill; pub mod misc; mod object_safety; mod on_unimplemented; +pub mod outlives_bounds; mod project; pub mod query; pub(crate) mod relationships; @@ -22,6 +23,7 @@ mod structural_match; mod util; pub mod wf; +use crate::errors::DumpVTableEntries; use crate::infer::outlives::env::OutlivesEnvironment; use crate::infer::{InferCtxt, TyCtxtInferExt}; use crate::traits::error_reporting::InferCtxtExt as _; @@ -30,10 +32,14 @@ use rustc_errors::ErrorGuaranteed; use rustc_hir as hir; use rustc_hir::def_id::DefId; use rustc_hir::lang_items::LangItem; +use rustc_infer::traits::TraitEngineExt as _; use rustc_middle::ty::fold::TypeFoldable; use rustc_middle::ty::subst::{InternalSubsts, SubstsRef}; use rustc_middle::ty::visit::TypeVisitable; -use rustc_middle::ty::{self, GenericParamDefKind, ToPredicate, Ty, TyCtxt, VtblEntry}; +use rustc_middle::ty::{ + self, DefIdTree, GenericParamDefKind, Subst, ToPredicate, Ty, TyCtxt, TypeSuperVisitable, + VtblEntry, +}; use rustc_span::{sym, Span}; use smallvec::SmallVec; @@ -113,11 +119,21 @@ pub enum TraitQueryMode { /// Creates predicate obligations from the generic bounds. pub fn predicates_for_generics<'tcx>( - cause: ObligationCause<'tcx>, + cause: impl Fn(usize, Span) -> ObligationCause<'tcx>, param_env: ty::ParamEnv<'tcx>, generic_bounds: ty::InstantiatedPredicates<'tcx>, ) -> impl Iterator<Item = PredicateObligation<'tcx>> { - util::predicates_for_generics(cause, 0, param_env, generic_bounds) + let generic_bounds = generic_bounds; + debug!("predicates_for_generics(generic_bounds={:?})", generic_bounds); + + std::iter::zip(generic_bounds.predicates, generic_bounds.spans).enumerate().map( + move |(idx, (predicate, span))| Obligation { + cause: cause(idx, span), + recursion_depth: 0, + param_env: param_env, + predicate, + }, + ) } /// Determines whether the type `ty` is known to meet `bound` and @@ -161,22 +177,20 @@ pub fn type_known_to_meet_bound_modulo_regions<'a, 'tcx>( // this function's result remains infallible, we must confirm // that guess. While imperfect, I believe this is sound. - // The handling of regions in this area of the code is terrible, - // see issue #29149. We should be able to improve on this with - // NLL. - let mut fulfill_cx = <dyn TraitEngine<'tcx>>::new(infcx.tcx); - // We can use a dummy node-id here because we won't pay any mind // to region obligations that arise (there shouldn't really be any // anyhow). let cause = ObligationCause::misc(span, hir::CRATE_HIR_ID); - fulfill_cx.register_bound(infcx, param_env, ty, def_id, cause); + // The handling of regions in this area of the code is terrible, + // see issue #29149. We should be able to improve on this with + // NLL. + let errors = fully_solve_bound(infcx, cause, param_env, ty, def_id); // Note: we only assume something is `Copy` if we can // *definitively* show that it implements `Copy`. Otherwise, // assume it is move; linear is always ok. - match fulfill_cx.select_all_or_error(infcx).as_slice() { + match &errors[..] { [] => { debug!( "type_known_to_meet_bound_modulo_regions: ty={:?} bound={} success", @@ -222,15 +236,13 @@ fn do_normalize_predicates<'tcx>( // them here too, and we will remove this function when // we move over to lazy normalization *anyway*. tcx.infer_ctxt().ignoring_regions().enter(|infcx| { - let fulfill_cx = FulfillmentContext::new(); - let predicates = - match fully_normalize(&infcx, fulfill_cx, cause, elaborated_env, predicates) { - Ok(predicates) => predicates, - Err(errors) => { - let reported = infcx.report_fulfillment_errors(&errors, None, false); - return Err(reported); - } - }; + let predicates = match fully_normalize(&infcx, cause, elaborated_env, predicates) { + Ok(predicates) => predicates, + Err(errors) => { + let reported = infcx.report_fulfillment_errors(&errors, None, false); + return Err(reported); + } + }; debug!("do_normalize_predictes: normalized predicates = {:?}", predicates); @@ -381,9 +393,9 @@ pub fn normalize_param_env_or_error<'tcx>( ) } +/// Normalize a type and process all resulting obligations, returning any errors pub fn fully_normalize<'a, 'tcx, T>( infcx: &InferCtxt<'a, 'tcx>, - mut fulfill_cx: FulfillmentContext<'tcx>, cause: ObligationCause<'tcx>, param_env: ty::ParamEnv<'tcx>, value: T, @@ -399,8 +411,10 @@ where "fully_normalize: normalized_value={:?} obligations={:?}", normalized_value, obligations ); + + let mut fulfill_cx = FulfillmentContext::new(); for obligation in obligations { - fulfill_cx.register_predicate_obligation(selcx.infcx(), obligation); + fulfill_cx.register_predicate_obligation(infcx, obligation); } debug!("fully_normalize: select_all_or_error start"); @@ -414,6 +428,43 @@ where Ok(resolved_value) } +/// Process an obligation (and any nested obligations that come from it) to +/// completion, returning any errors +pub fn fully_solve_obligation<'a, 'tcx>( + infcx: &InferCtxt<'a, 'tcx>, + obligation: PredicateObligation<'tcx>, +) -> Vec<FulfillmentError<'tcx>> { + let mut engine = <dyn TraitEngine<'tcx>>::new(infcx.tcx); + engine.register_predicate_obligation(infcx, obligation); + engine.select_all_or_error(infcx) +} + +/// Process a set of obligations (and any nested obligations that come from them) +/// to completion +pub fn fully_solve_obligations<'a, 'tcx>( + infcx: &InferCtxt<'a, 'tcx>, + obligations: impl IntoIterator<Item = PredicateObligation<'tcx>>, +) -> Vec<FulfillmentError<'tcx>> { + let mut engine = <dyn TraitEngine<'tcx>>::new(infcx.tcx); + engine.register_predicate_obligations(infcx, obligations); + engine.select_all_or_error(infcx) +} + +/// Process a bound (and any nested obligations that come from it) to completion. +/// This is a convenience function for traits that have no generic arguments, such +/// as auto traits, and builtin traits like Copy or Sized. +pub fn fully_solve_bound<'a, 'tcx>( + infcx: &InferCtxt<'a, 'tcx>, + cause: ObligationCause<'tcx>, + param_env: ty::ParamEnv<'tcx>, + ty: Ty<'tcx>, + bound: DefId, +) -> Vec<FulfillmentError<'tcx>> { + let mut engine = <dyn TraitEngine<'tcx>>::new(infcx.tcx); + engine.register_bound(infcx, param_env, ty, bound, cause); + engine.select_all_or_error(infcx) +} + /// Normalizes the predicates and checks whether they hold in an empty environment. If this /// returns true, then either normalize encountered an error or one of the predicates did not /// hold. Used when creating vtables to check for unsatisfiable methods. @@ -424,24 +475,14 @@ pub fn impossible_predicates<'tcx>( debug!("impossible_predicates(predicates={:?})", predicates); let result = tcx.infer_ctxt().enter(|infcx| { - // HACK: Set tainted by errors to gracefully exit in case of overflow. - infcx.set_tainted_by_errors(); - let param_env = ty::ParamEnv::reveal_all(); - let mut selcx = SelectionContext::new(&infcx); - let mut fulfill_cx = FulfillmentContext::new(); - let cause = ObligationCause::dummy(); - let Normalized { value: predicates, obligations } = - normalize(&mut selcx, param_env, cause.clone(), predicates); - for obligation in obligations { - fulfill_cx.register_predicate_obligation(&infcx, obligation); - } + let ocx = ObligationCtxt::new(&infcx); + let predicates = ocx.normalize(ObligationCause::dummy(), param_env, predicates); for predicate in predicates { - let obligation = Obligation::new(cause.clone(), param_env, predicate); - fulfill_cx.register_predicate_obligation(&infcx, obligation); + let obligation = Obligation::new(ObligationCause::dummy(), param_env, predicate); + ocx.register_obligation(obligation); } - - let errors = fulfill_cx.select_all_or_error(&infcx); + let errors = ocx.select_all_or_error(); // Clean up after ourselves let _ = infcx.inner.borrow_mut().opaque_type_storage.take_opaque_types(); @@ -474,6 +515,84 @@ fn subst_and_check_impossible_predicates<'tcx>( result } +/// Checks whether a trait's method is impossible to call on a given impl. +/// +/// This only considers predicates that reference the impl's generics, and not +/// those that reference the method's generics. +fn is_impossible_method<'tcx>( + tcx: TyCtxt<'tcx>, + (impl_def_id, trait_item_def_id): (DefId, DefId), +) -> bool { + struct ReferencesOnlyParentGenerics<'tcx> { + tcx: TyCtxt<'tcx>, + generics: &'tcx ty::Generics, + trait_item_def_id: DefId, + } + impl<'tcx> ty::TypeVisitor<'tcx> for ReferencesOnlyParentGenerics<'tcx> { + type BreakTy = (); + fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> { + // If this is a parameter from the trait item's own generics, then bail + if let ty::Param(param) = t.kind() + && let param_def_id = self.generics.type_param(param, self.tcx).def_id + && self.tcx.parent(param_def_id) == self.trait_item_def_id + { + return ControlFlow::BREAK; + } + t.super_visit_with(self) + } + fn visit_region(&mut self, r: ty::Region<'tcx>) -> ControlFlow<Self::BreakTy> { + if let ty::ReEarlyBound(param) = r.kind() + && let param_def_id = self.generics.region_param(¶m, self.tcx).def_id + && self.tcx.parent(param_def_id) == self.trait_item_def_id + { + return ControlFlow::BREAK; + } + r.super_visit_with(self) + } + fn visit_const(&mut self, ct: ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> { + if let ty::ConstKind::Param(param) = ct.kind() + && let param_def_id = self.generics.const_param(¶m, self.tcx).def_id + && self.tcx.parent(param_def_id) == self.trait_item_def_id + { + return ControlFlow::BREAK; + } + ct.super_visit_with(self) + } + } + + let generics = tcx.generics_of(trait_item_def_id); + let predicates = tcx.predicates_of(trait_item_def_id); + let impl_trait_ref = + tcx.impl_trait_ref(impl_def_id).expect("expected impl to correspond to trait"); + let param_env = tcx.param_env(impl_def_id); + + let mut visitor = ReferencesOnlyParentGenerics { tcx, generics, trait_item_def_id }; + let predicates_for_trait = predicates.predicates.iter().filter_map(|(pred, span)| { + if pred.visit_with(&mut visitor).is_continue() { + Some(Obligation::new( + ObligationCause::dummy_with_span(*span), + param_env, + ty::EarlyBinder(*pred).subst(tcx, impl_trait_ref.substs), + )) + } else { + None + } + }); + + tcx.infer_ctxt().ignoring_regions().enter(|ref infcx| { + for obligation in predicates_for_trait { + // Ignore overflow error, to be conservative. + if let Ok(result) = infcx.evaluate_obligation(&obligation) + && !result.may_apply() + { + return true; + } + } + + false + }) +} + #[derive(Clone, Debug)] enum VtblSegment<'tcx> { MetadataDSA, @@ -645,8 +764,11 @@ fn dump_vtable_entries<'tcx>( trait_ref: ty::PolyTraitRef<'tcx>, entries: &[VtblEntry<'tcx>], ) { - let msg = format!("vtable entries for `{}`: {:#?}", trait_ref, entries); - tcx.sess.struct_span_err(sp, &msg).emit(); + tcx.sess.emit_err(DumpVTableEntries { + span: sp, + trait_ref, + entries: format!("{:#?}", entries), + }); } fn own_existential_vtable_entries<'tcx>( @@ -849,11 +971,12 @@ pub fn provide(providers: &mut ty::query::Providers) { *providers = ty::query::Providers { specialization_graph_of: specialize::specialization_graph_provider, specializes: specialize::specializes, - codegen_fulfill_obligation: codegen::codegen_fulfill_obligation, + codegen_select_candidate: codegen::codegen_select_candidate, own_existential_vtable_entries, vtable_entries, vtable_trait_upcasting_coercion_new_vptr_slot, subst_and_check_impossible_predicates, + is_impossible_method, try_unify_abstract_consts: |tcx, param_env_and| { let (param_env, (a, b)) = param_env_and.into_parts(); const_evaluatable::try_unify_abstract_consts(tcx, (a, b), param_env) diff --git a/compiler/rustc_trait_selection/src/traits/object_safety.rs b/compiler/rustc_trait_selection/src/traits/object_safety.rs index 612f51309..f2779ce2d 100644 --- a/compiler/rustc_trait_selection/src/traits/object_safety.rs +++ b/compiler/rustc_trait_selection/src/traits/object_safety.rs @@ -13,6 +13,7 @@ use super::elaborate_predicates; use crate::infer::TyCtxtInferExt; use crate::traits::query::evaluate_obligation::InferCtxtExt; use crate::traits::{self, Obligation, ObligationCause}; +use hir::def::DefKind; use rustc_errors::{FatalError, MultiSpan}; use rustc_hir as hir; use rustc_hir::def_id::DefId; @@ -431,6 +432,9 @@ fn virtual_call_violation_for_method<'tcx>( if contains_illegal_self_type_reference(tcx, trait_def_id, sig.output()) { return Some(MethodViolationCode::ReferencesSelfOutput); } + if contains_illegal_impl_trait_in_trait(tcx, sig.output()) { + return Some(MethodViolationCode::ReferencesImplTraitInTrait); + } // We can't monomorphize things like `fn foo<A>(...)`. let own_counts = tcx.generics_of(method.def_id).own_counts(); @@ -596,7 +600,7 @@ fn object_ty_for_trait<'tcx>( let existential_predicates = tcx .mk_poly_existential_predicates(iter::once(trait_predicate).chain(projection_predicates)); - let object_ty = tcx.mk_dynamic(existential_predicates, lifetime); + let object_ty = tcx.mk_dynamic(existential_predicates, lifetime, ty::Dyn); debug!("object_ty_for_trait: object_ty=`{}`", object_ty); @@ -793,6 +797,12 @@ fn contains_illegal_self_type_reference<'tcx, T: TypeVisitable<'tcx>>( ControlFlow::CONTINUE } } + ty::Projection(ref data) + if self.tcx.def_kind(data.item_def_id) == DefKind::ImplTraitPlaceholder => + { + // We'll deny these later in their own pass + ControlFlow::CONTINUE + } ty::Projection(ref data) => { // This is a projected type `<Foo as SomeTrait>::X`. @@ -861,6 +871,22 @@ fn contains_illegal_self_type_reference<'tcx, T: TypeVisitable<'tcx>>( .is_break() } +pub fn contains_illegal_impl_trait_in_trait<'tcx>( + tcx: TyCtxt<'tcx>, + ty: ty::Binder<'tcx, Ty<'tcx>>, +) -> bool { + // FIXME(RPITIT): Perhaps we should use a visitor here? + ty.skip_binder().walk().any(|arg| { + if let ty::GenericArgKind::Type(ty) = arg.unpack() + && let ty::Projection(proj) = ty.kind() + { + tcx.def_kind(proj.item_def_id) == DefKind::ImplTraitPlaceholder + } else { + false + } + }) +} + pub fn provide(providers: &mut ty::query::Providers) { *providers = ty::query::Providers { object_safety_violations, ..*providers }; } diff --git a/compiler/rustc_trait_selection/src/traits/on_unimplemented.rs b/compiler/rustc_trait_selection/src/traits/on_unimplemented.rs index 9227bbf01..4a4f34b76 100644 --- a/compiler/rustc_trait_selection/src/traits/on_unimplemented.rs +++ b/compiler/rustc_trait_selection/src/traits/on_unimplemented.rs @@ -8,6 +8,10 @@ use rustc_parse_format::{ParseMode, Parser, Piece, Position}; use rustc_span::symbol::{kw, sym, Symbol}; use rustc_span::{Span, DUMMY_SP}; +use crate::errors::{ + EmptyOnClauseInOnUnimplemented, InvalidOnClauseInOnUnimplemented, NoValueInOnUnimplemented, +}; + #[derive(Clone, Debug)] pub struct OnUnimplementedFormatString(Symbol); @@ -18,7 +22,7 @@ pub struct OnUnimplementedDirective { pub message: Option<OnUnimplementedFormatString>, pub label: Option<OnUnimplementedFormatString>, pub note: Option<OnUnimplementedFormatString>, - pub enclosing_scope: Option<OnUnimplementedFormatString>, + pub parent_label: Option<OnUnimplementedFormatString>, pub append_const_msg: Option<Option<Symbol>>, } @@ -27,7 +31,7 @@ pub struct OnUnimplementedNote { pub message: Option<String>, pub label: Option<String>, pub note: Option<String>, - pub enclosing_scope: Option<String>, + pub parent_label: Option<String>, /// Append a message for `~const Trait` errors. `None` means not requested and /// should fallback to a generic message, `Some(None)` suggests using the default /// appended message, `Some(Some(s))` suggests use the `s` message instead of the @@ -35,21 +39,6 @@ pub struct OnUnimplementedNote { pub append_const_msg: Option<Option<Symbol>>, } -fn parse_error( - tcx: TyCtxt<'_>, - span: Span, - message: &str, - label: &str, - note: Option<&str>, -) -> ErrorGuaranteed { - let mut diag = struct_span_err!(tcx.sess, span, E0232, "{}", message); - diag.span_label(span, label); - if let Some(note) = note { - diag.note(note); - } - diag.emit() -} - impl<'tcx> OnUnimplementedDirective { fn parse( tcx: TyCtxt<'tcx>, @@ -70,25 +59,9 @@ impl<'tcx> OnUnimplementedDirective { } else { let cond = item_iter .next() - .ok_or_else(|| { - parse_error( - tcx, - span, - "empty `on`-clause in `#[rustc_on_unimplemented]`", - "empty on-clause here", - None, - ) - })? + .ok_or_else(|| tcx.sess.emit_err(EmptyOnClauseInOnUnimplemented { span }))? .meta_item() - .ok_or_else(|| { - parse_error( - tcx, - span, - "invalid `on`-clause in `#[rustc_on_unimplemented]`", - "invalid on-clause here", - None, - ) - })?; + .ok_or_else(|| tcx.sess.emit_err(InvalidOnClauseInOnUnimplemented { span }))?; attr::eval_condition(cond, &tcx.sess.parse_sess, Some(tcx.features()), &mut |cfg| { if let Some(value) = cfg.value && let Err(guar) = parse_value(value) { errored = Some(guar); @@ -101,7 +74,7 @@ impl<'tcx> OnUnimplementedDirective { let mut message = None; let mut label = None; let mut note = None; - let mut enclosing_scope = None; + let mut parent_label = None; let mut subcommands = vec![]; let mut append_const_msg = None; @@ -121,9 +94,9 @@ impl<'tcx> OnUnimplementedDirective { note = parse_value(note_)?; continue; } - } else if item.has_name(sym::enclosing_scope) && enclosing_scope.is_none() { - if let Some(enclosing_scope_) = item.value_str() { - enclosing_scope = parse_value(enclosing_scope_)?; + } else if item.has_name(sym::parent_label) && parent_label.is_none() { + if let Some(parent_label_) = item.value_str() { + parent_label = parse_value(parent_label_)?; continue; } } else if item.has_name(sym::on) @@ -150,13 +123,7 @@ impl<'tcx> OnUnimplementedDirective { } // nothing found - parse_error( - tcx, - item.span(), - "this attribute must have a valid value", - "expected value here", - Some(r#"eg `#[rustc_on_unimplemented(message="foo")]`"#), - ); + tcx.sess.emit_err(NoValueInOnUnimplemented { span: item.span() }); } if let Some(reported) = errored { @@ -168,7 +135,7 @@ impl<'tcx> OnUnimplementedDirective { message, label, note, - enclosing_scope, + parent_label, append_const_msg, }) } @@ -193,7 +160,7 @@ impl<'tcx> OnUnimplementedDirective { attr.span, )?), note: None, - enclosing_scope: None, + parent_label: None, append_const_msg: None, })) } else { @@ -214,7 +181,7 @@ impl<'tcx> OnUnimplementedDirective { let mut message = None; let mut label = None; let mut note = None; - let mut enclosing_scope = None; + let mut parent_label = None; let mut append_const_msg = None; info!("evaluate({:?}, trait_ref={:?}, options={:?})", self, trait_ref, options); @@ -250,8 +217,8 @@ impl<'tcx> OnUnimplementedDirective { note = Some(note_.clone()); } - if let Some(ref enclosing_scope_) = command.enclosing_scope { - enclosing_scope = Some(enclosing_scope_.clone()); + if let Some(ref parent_label_) = command.parent_label { + parent_label = Some(parent_label_.clone()); } append_const_msg = command.append_const_msg; @@ -261,7 +228,7 @@ impl<'tcx> OnUnimplementedDirective { label: label.map(|l| l.format(tcx, trait_ref, &options_map)), message: message.map(|m| m.format(tcx, trait_ref, &options_map)), note: note.map(|n| n.format(tcx, trait_ref, &options_map)), - enclosing_scope: enclosing_scope.map(|e_s| e_s.format(tcx, trait_ref, &options_map)), + parent_label: parent_label.map(|e_s| e_s.format(tcx, trait_ref, &options_map)), append_const_msg, } } diff --git a/compiler/rustc_trait_selection/src/traits/outlives_bounds.rs b/compiler/rustc_trait_selection/src/traits/outlives_bounds.rs new file mode 100644 index 000000000..3008dfcad --- /dev/null +++ b/compiler/rustc_trait_selection/src/traits/outlives_bounds.rs @@ -0,0 +1,115 @@ +use crate::infer::InferCtxt; +use crate::traits::query::type_op::{self, TypeOp, TypeOpOutput}; +use crate::traits::query::NoSolution; +use crate::traits::{ObligationCause, TraitEngine, TraitEngineExt}; +use rustc_data_structures::fx::FxHashSet; +use rustc_hir as hir; +use rustc_hir::HirId; +use rustc_middle::ty::{self, ParamEnv, Ty}; + +pub use rustc_middle::traits::query::OutlivesBound; + +type Bounds<'a, 'tcx: 'a> = impl Iterator<Item = OutlivesBound<'tcx>> + 'a; +pub trait InferCtxtExt<'a, 'tcx> { + fn implied_outlives_bounds( + &self, + param_env: ty::ParamEnv<'tcx>, + body_id: hir::HirId, + ty: Ty<'tcx>, + ) -> Vec<OutlivesBound<'tcx>>; + + fn implied_bounds_tys( + &'a self, + param_env: ty::ParamEnv<'tcx>, + body_id: hir::HirId, + tys: FxHashSet<Ty<'tcx>>, + ) -> Bounds<'a, 'tcx>; +} + +impl<'a, 'cx, 'tcx: 'a> InferCtxtExt<'a, 'tcx> for InferCtxt<'cx, 'tcx> { + /// Implied bounds are region relationships that we deduce + /// automatically. The idea is that (e.g.) a caller must check that a + /// function's argument types are well-formed immediately before + /// calling that fn, and hence the *callee* can assume that its + /// argument types are well-formed. This may imply certain relationships + /// between generic parameters. For example: + /// ``` + /// fn foo<'a,T>(x: &'a T) {} + /// ``` + /// can only be called with a `'a` and `T` such that `&'a T` is WF. + /// For `&'a T` to be WF, `T: 'a` must hold. So we can assume `T: 'a`. + /// + /// # Parameters + /// + /// - `param_env`, the where-clauses in scope + /// - `body_id`, the body-id to use when normalizing assoc types. + /// Note that this may cause outlives obligations to be injected + /// into the inference context with this body-id. + /// - `ty`, the type that we are supposed to assume is WF. + #[instrument(level = "debug", skip(self, param_env, body_id), ret)] + fn implied_outlives_bounds( + &self, + param_env: ty::ParamEnv<'tcx>, + body_id: hir::HirId, + ty: Ty<'tcx>, + ) -> Vec<OutlivesBound<'tcx>> { + let span = self.tcx.hir().span(body_id); + let result = param_env + .and(type_op::implied_outlives_bounds::ImpliedOutlivesBounds { ty }) + .fully_perform(self); + let result = match result { + Ok(r) => r, + Err(NoSolution) => { + self.tcx.sess.delay_span_bug( + span, + "implied_outlives_bounds failed to solve all obligations", + ); + return vec![]; + } + }; + + let TypeOpOutput { output, constraints, .. } = result; + + if let Some(constraints) = constraints { + debug!(?constraints); + // Instantiation may have produced new inference variables and constraints on those + // variables. Process these constraints. + let mut fulfill_cx = <dyn TraitEngine<'tcx>>::new(self.tcx); + let cause = ObligationCause::misc(span, body_id); + for &constraint in &constraints.outlives { + let obligation = self.query_outlives_constraint_to_obligation( + constraint, + cause.clone(), + param_env, + ); + fulfill_cx.register_predicate_obligation(self, obligation); + } + if !constraints.member_constraints.is_empty() { + span_bug!(span, "{:#?}", constraints.member_constraints); + } + let errors = fulfill_cx.select_all_or_error(self); + if !errors.is_empty() { + self.tcx.sess.delay_span_bug( + span, + "implied_outlives_bounds failed to solve obligations from instantiation", + ); + } + }; + + output + } + + fn implied_bounds_tys( + &'a self, + param_env: ParamEnv<'tcx>, + body_id: HirId, + tys: FxHashSet<Ty<'tcx>>, + ) -> Bounds<'a, 'tcx> { + tys.into_iter() + .map(move |ty| { + let ty = self.resolve_vars_if_possible(ty); + self.implied_outlives_bounds(param_env, body_id, ty) + }) + .flatten() + } +} diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs index c4e80e1ba..a25fb8543 100644 --- a/compiler/rustc_trait_selection/src/traits/project.rs +++ b/compiler/rustc_trait_selection/src/traits/project.rs @@ -32,6 +32,7 @@ use rustc_middle::traits::select::OverflowError; use rustc_middle::ty::fold::{TypeFoldable, TypeFolder, TypeSuperFoldable}; use rustc_middle::ty::subst::Subst; use rustc_middle::ty::visit::{MaxUniverse, TypeVisitable}; +use rustc_middle::ty::DefIdTree; use rustc_middle::ty::{self, Term, ToPredicate, Ty, TyCtxt}; use rustc_span::symbol::sym; @@ -70,6 +71,8 @@ enum ProjectionCandidate<'tcx> { /// From an "impl" (or a "pseudo-impl" returned by select) Select(Selection<'tcx>), + + ImplTraitInTrait(ImplSourceUserDefinedData<'tcx, PredicateObligation<'tcx>>), } enum ProjectionCandidateSet<'tcx> { @@ -231,7 +234,7 @@ pub(super) fn poly_project_and_unify_type<'cx, 'tcx>( /// If successful, this may result in additional obligations. /// /// See [poly_project_and_unify_type] for an explanation of the return value. -#[tracing::instrument(level = "debug", skip(selcx))] +#[instrument(level = "debug", skip(selcx))] fn project_and_unify_type<'cx, 'tcx>( selcx: &mut SelectionContext<'cx, 'tcx>, obligation: &ProjectionObligation<'tcx>, @@ -552,8 +555,23 @@ impl<'a, 'b, 'tcx> TypeFolder<'tcx> for AssocTypeNormalizer<'a, 'b, 'tcx> { ) .ok() .flatten() - .unwrap_or_else(|| ty::Term::Ty(ty.super_fold_with(self))) + .unwrap_or_else(|| ty.super_fold_with(self).into()) }; + // For cases like #95134 we would like to catch overflows early + // otherwise they slip away away and cause ICE. + let recursion_limit = self.tcx().recursion_limit(); + if !recursion_limit.value_within_limit(self.depth) + // HACK: Don't overflow when running cargo doc see #100991 + && !self.tcx().sess.opts.actually_rustdoc + { + let obligation = Obligation::with_depth( + self.cause.clone(), + recursion_limit.0, + self.param_env, + ty, + ); + self.selcx.infcx().report_overflow_error(&obligation, true); + } debug!( ?self.depth, ?ty, @@ -620,13 +638,27 @@ impl<'a, 'b, 'tcx> TypeFolder<'tcx> for AssocTypeNormalizer<'a, 'b, 'tcx> { #[instrument(skip(self), level = "debug")] fn fold_const(&mut self, constant: ty::Const<'tcx>) -> ty::Const<'tcx> { - if self.selcx.tcx().lazy_normalization() || !self.eager_inference_replacement { + let tcx = self.selcx.tcx(); + if tcx.lazy_normalization() { constant } else { let constant = constant.super_fold_with(self); - debug!(?constant); - debug!("self.param_env: {:?}", self.param_env); - constant.eval(self.selcx.tcx(), self.param_env) + debug!(?constant, ?self.param_env); + with_replaced_escaping_bound_vars( + self.selcx.infcx(), + &mut self.universes, + constant, + |constant| constant.eval(tcx, self.param_env), + ) + } + } + + #[inline] + fn fold_predicate(&mut self, p: ty::Predicate<'tcx>) -> ty::Predicate<'tcx> { + if p.allow_normalization() && needs_normalization(&p, self.param_env.reveal()) { + p.super_fold_with(self) + } else { + p } } } @@ -647,6 +679,41 @@ pub struct BoundVarReplacer<'me, 'tcx> { universe_indices: &'me mut Vec<Option<ty::UniverseIndex>>, } +/// Executes `f` on `value` after replacing all escaping bound variables with placeholders +/// and then replaces these placeholders with the original bound variables in the result. +/// +/// In most places, bound variables should be replaced right when entering a binder, making +/// this function unnecessary. However, normalization currently does not do that, so we have +/// to do this lazily. +/// +/// You should not add any additional uses of this function, at least not without first +/// discussing it with t-types. +/// +/// FIXME(@lcnr): We may even consider experimenting with eagerly replacing bound vars during +/// normalization as well, at which point this function will be unnecessary and can be removed. +pub fn with_replaced_escaping_bound_vars<'a, 'tcx, T: TypeFoldable<'tcx>, R: TypeFoldable<'tcx>>( + infcx: &'a InferCtxt<'a, 'tcx>, + universe_indices: &'a mut Vec<Option<ty::UniverseIndex>>, + value: T, + f: impl FnOnce(T) -> R, +) -> R { + if value.has_escaping_bound_vars() { + let (value, mapped_regions, mapped_types, mapped_consts) = + BoundVarReplacer::replace_bound_vars(infcx, universe_indices, value); + let result = f(value); + PlaceholderReplacer::replace_placeholders( + infcx, + mapped_regions, + mapped_types, + mapped_consts, + universe_indices, + result, + ) + } else { + f(value) + } +} + impl<'me, 'tcx> BoundVarReplacer<'me, 'tcx> { /// Returns `Some` if we *were* able to replace bound vars. If there are any bound vars that /// use a binding level above `universe_indices.len()`, we fail. @@ -1182,7 +1249,7 @@ impl<'tcx> Progress<'tcx> { /// /// IMPORTANT: /// - `obligation` must be fully normalized -#[tracing::instrument(level = "info", skip(selcx))] +#[instrument(level = "info", skip(selcx))] fn project<'cx, 'tcx>( selcx: &mut SelectionContext<'cx, 'tcx>, obligation: &ProjectionTyObligation<'tcx>, @@ -1201,6 +1268,8 @@ fn project<'cx, 'tcx>( let mut candidates = ProjectionCandidateSet::None; + assemble_candidate_for_impl_trait_in_trait(selcx, obligation, &mut candidates); + // Make sure that the following procedures are kept in order. ParamEnv // needs to be first because it has highest priority, and Select checks // the return value of push_candidate which assumes it's ran at last. @@ -1239,6 +1308,48 @@ fn project<'cx, 'tcx>( } } +/// If the predicate's item is an `ImplTraitPlaceholder`, we do a select on the +/// corresponding trait ref. If this yields an `impl`, then we're able to project +/// to a concrete type, since we have an `impl`'s method to provide the RPITIT. +fn assemble_candidate_for_impl_trait_in_trait<'cx, 'tcx>( + selcx: &mut SelectionContext<'cx, 'tcx>, + obligation: &ProjectionTyObligation<'tcx>, + candidate_set: &mut ProjectionCandidateSet<'tcx>, +) { + let tcx = selcx.tcx(); + if tcx.def_kind(obligation.predicate.item_def_id) == DefKind::ImplTraitPlaceholder { + let trait_fn_def_id = tcx.impl_trait_in_trait_parent(obligation.predicate.item_def_id); + let trait_def_id = tcx.parent(trait_fn_def_id); + let trait_substs = + obligation.predicate.substs.truncate_to(tcx, tcx.generics_of(trait_def_id)); + // FIXME(named-returns): Binders + let trait_predicate = + ty::Binder::dummy(ty::TraitRef { def_id: trait_def_id, substs: trait_substs }) + .to_poly_trait_predicate(); + + let _ = + selcx.infcx().commit_if_ok(|_| match selcx.select(&obligation.with(trait_predicate)) { + Ok(Some(super::ImplSource::UserDefined(data))) => { + candidate_set.push_candidate(ProjectionCandidate::ImplTraitInTrait(data)); + Ok(()) + } + Ok(None) => { + candidate_set.mark_ambiguous(); + return Err(()); + } + Ok(Some(_)) => { + // Don't know enough about the impl to provide a useful signature + return Err(()); + } + Err(e) => { + debug!(error = ?e, "selection error"); + candidate_set.mark_error(e); + return Err(()); + } + }); + } +} + /// The first thing we have to do is scan through the parameter /// environment to see whether there are any projection predicates /// there that can answer this question. @@ -1344,7 +1455,7 @@ fn assemble_candidates_from_object_ty<'cx, 'tcx>( ); } -#[tracing::instrument( +#[instrument( level = "debug", skip(selcx, candidate_set, ctor, env_predicates, potentially_unnormalized_candidates) )] @@ -1395,12 +1506,17 @@ fn assemble_candidates_from_predicates<'cx, 'tcx>( } } -#[tracing::instrument(level = "debug", skip(selcx, obligation, candidate_set))] +#[instrument(level = "debug", skip(selcx, obligation, candidate_set))] fn assemble_candidates_from_impls<'cx, 'tcx>( selcx: &mut SelectionContext<'cx, 'tcx>, obligation: &ProjectionTyObligation<'tcx>, candidate_set: &mut ProjectionCandidateSet<'tcx>, ) { + // Can't assemble candidate from impl for RPITIT + if selcx.tcx().def_kind(obligation.predicate.item_def_id) == DefKind::ImplTraitPlaceholder { + return; + } + // If we are resolving `<T as TraitRef<...>>::Item == Type`, // start out by selecting the predicate `T as TraitRef<...>`: let poly_trait_ref = ty::Binder::dummy(obligation.predicate.trait_ref(selcx.tcx())); @@ -1635,7 +1751,8 @@ fn assemble_candidates_from_impls<'cx, 'tcx>( super::ImplSource::AutoImpl(..) | super::ImplSource::Builtin(..) | super::ImplSource::TraitUpcasting(_) - | super::ImplSource::ConstDestruct(_) => { + | super::ImplSource::ConstDestruct(_) + | super::ImplSource::Tuple => { // These traits have no associated types. selcx.tcx().sess.delay_span_bug( obligation.cause.span, @@ -1676,6 +1793,9 @@ fn confirm_candidate<'cx, 'tcx>( ProjectionCandidate::Select(impl_source) => { confirm_select_candidate(selcx, obligation, impl_source) } + ProjectionCandidate::ImplTraitInTrait(data) => { + confirm_impl_trait_in_trait_candidate(selcx, obligation, data) + } }; // When checking for cycle during evaluation, we compare predicates with @@ -1710,7 +1830,8 @@ fn confirm_select_candidate<'cx, 'tcx>( | super::ImplSource::Builtin(..) | super::ImplSource::TraitUpcasting(_) | super::ImplSource::TraitAlias(..) - | super::ImplSource::ConstDestruct(_) => { + | super::ImplSource::ConstDestruct(_) + | super::ImplSource::Tuple => { // we don't create Select candidates with this kind of resolution span_bug!( obligation.cause.span, @@ -2038,10 +2159,74 @@ fn confirm_impl_candidate<'cx, 'tcx>( } } +fn confirm_impl_trait_in_trait_candidate<'tcx>( + selcx: &mut SelectionContext<'_, 'tcx>, + obligation: &ProjectionTyObligation<'tcx>, + data: ImplSourceUserDefinedData<'tcx, PredicateObligation<'tcx>>, +) -> Progress<'tcx> { + let tcx = selcx.tcx(); + let mut obligations = data.nested; + + let trait_fn_def_id = tcx.impl_trait_in_trait_parent(obligation.predicate.item_def_id); + let Ok(leaf_def) = assoc_def(selcx, data.impl_def_id, trait_fn_def_id) else { + return Progress { term: tcx.ty_error().into(), obligations }; + }; + if !leaf_def.item.defaultness(tcx).has_value() { + return Progress { term: tcx.ty_error().into(), obligations }; + } + + let impl_fn_def_id = leaf_def.item.def_id; + let impl_fn_substs = obligation.predicate.substs.rebase_onto(tcx, trait_fn_def_id, data.substs); + + let cause = ObligationCause::new( + obligation.cause.span, + obligation.cause.body_id, + super::ItemObligation(impl_fn_def_id), + ); + let predicates = normalize_with_depth_to( + selcx, + obligation.param_env, + cause.clone(), + obligation.recursion_depth + 1, + tcx.predicates_of(impl_fn_def_id).instantiate(tcx, impl_fn_substs), + &mut obligations, + ); + obligations.extend(std::iter::zip(predicates.predicates, predicates.spans).map( + |(pred, span)| { + Obligation::with_depth( + ObligationCause::new( + obligation.cause.span, + obligation.cause.body_id, + if span.is_dummy() { + super::ItemObligation(impl_fn_def_id) + } else { + super::BindingObligation(impl_fn_def_id, span) + }, + ), + obligation.recursion_depth + 1, + obligation.param_env, + pred, + ) + }, + )); + + let ty = super::normalize_to( + selcx, + obligation.param_env, + cause.clone(), + tcx.bound_trait_impl_trait_tys(impl_fn_def_id) + .map_bound(|tys| { + tys.map_or_else(|_| tcx.ty_error(), |tys| tys[&obligation.predicate.item_def_id]) + }) + .subst(tcx, impl_fn_substs), + &mut obligations, + ); + + Progress { term: ty.into(), obligations } +} + // Get obligations corresponding to the predicates from the where-clause of the // associated type itself. -// Note: `feature(generic_associated_types)` is required to write such -// predicates, even for non-generic associated types. fn assoc_ty_own_obligations<'cx, 'tcx>( selcx: &mut SelectionContext<'cx, 'tcx>, obligation: &ProjectionTyObligation<'tcx>, diff --git a/compiler/rustc_trait_selection/src/traits/query/normalize.rs b/compiler/rustc_trait_selection/src/traits/query/normalize.rs index 449d7a7b4..40acabf62 100644 --- a/compiler/rustc_trait_selection/src/traits/query/normalize.rs +++ b/compiler/rustc_trait_selection/src/traits/query/normalize.rs @@ -6,7 +6,7 @@ use crate::infer::at::At; use crate::infer::canonical::OriginalQueryValues; use crate::infer::{InferCtxt, InferOk}; use crate::traits::error_reporting::InferCtxtExt; -use crate::traits::project::needs_normalization; +use crate::traits::project::{needs_normalization, BoundVarReplacer, PlaceholderReplacer}; use crate::traits::{Obligation, ObligationCause, PredicateObligation, Reveal}; use rustc_data_structures::sso::SsoHashMap; use rustc_data_structures::stack::ensure_sufficient_stack; @@ -48,10 +48,11 @@ impl<'cx, 'tcx> AtExt<'tcx> for At<'cx, 'tcx> { T: TypeFoldable<'tcx>, { debug!( - "normalize::<{}>(value={:?}, param_env={:?})", + "normalize::<{}>(value={:?}, param_env={:?}, cause={:?})", std::any::type_name::<T>(), value, self.param_env, + self.cause, ); if !needs_normalization(&value, self.param_env.reveal()) { return Ok(Normalized { value, obligations: vec![] }); @@ -266,7 +267,15 @@ impl<'cx, 'tcx> FallibleTypeFolder<'tcx> for QueryNormalizer<'cx, 'tcx> { debug!("QueryNormalizer: result = {:#?}", result); debug!("QueryNormalizer: obligations = {:#?}", obligations); self.obligations.extend(obligations); - Ok(result.normalized_ty) + + let res = result.normalized_ty; + // `tcx.normalize_projection_ty` may normalize to a type that still has + // unevaluated consts, so keep normalizing here if that's the case. + if res != ty && res.has_type_flags(ty::TypeFlags::HAS_CT_PROJECTION) { + Ok(res.try_super_fold_with(self)?) + } else { + Ok(res) + } } ty::Projection(data) => { @@ -275,11 +284,7 @@ impl<'cx, 'tcx> FallibleTypeFolder<'tcx> for QueryNormalizer<'cx, 'tcx> { let tcx = self.infcx.tcx; let infcx = self.infcx; let (data, mapped_regions, mapped_types, mapped_consts) = - crate::traits::project::BoundVarReplacer::replace_bound_vars( - infcx, - &mut self.universes, - data, - ); + BoundVarReplacer::replace_bound_vars(infcx, &mut self.universes, data); let data = data.try_fold_with(self)?; let mut orig_values = OriginalQueryValues::default(); @@ -305,18 +310,26 @@ impl<'cx, 'tcx> FallibleTypeFolder<'tcx> for QueryNormalizer<'cx, 'tcx> { debug!("QueryNormalizer: result = {:#?}", result); debug!("QueryNormalizer: obligations = {:#?}", obligations); self.obligations.extend(obligations); - Ok(crate::traits::project::PlaceholderReplacer::replace_placeholders( + let res = PlaceholderReplacer::replace_placeholders( infcx, mapped_regions, mapped_types, mapped_consts, &self.universes, result.normalized_ty, - )) + ); + // `tcx.normalize_projection_ty` may normalize to a type that still has + // unevaluated consts, so keep normalizing here if that's the case. + if res != ty && res.has_type_flags(ty::TypeFlags::HAS_CT_PROJECTION) { + Ok(res.try_super_fold_with(self)?) + } else { + Ok(res) + } } _ => ty.try_super_fold_with(self), })()?; + self.cache.insert(ty, res); Ok(res) } @@ -326,7 +339,13 @@ impl<'cx, 'tcx> FallibleTypeFolder<'tcx> for QueryNormalizer<'cx, 'tcx> { constant: ty::Const<'tcx>, ) -> Result<ty::Const<'tcx>, Self::Error> { let constant = constant.try_super_fold_with(self)?; - Ok(constant.eval(self.infcx.tcx, self.param_env)) + debug!(?constant, ?self.param_env); + Ok(crate::traits::project::with_replaced_escaping_bound_vars( + self.infcx, + &mut self.universes, + constant, + |constant| constant.eval(self.infcx.tcx, self.param_env), + )) } fn try_fold_mir_const( @@ -348,7 +367,21 @@ impl<'cx, 'tcx> FallibleTypeFolder<'tcx> for QueryNormalizer<'cx, 'tcx> { _ => mir::ConstantKind::Ty(const_folded), } } - mir::ConstantKind::Val(_, _) => constant.try_super_fold_with(self)?, + mir::ConstantKind::Val(_, _) | mir::ConstantKind::Unevaluated(..) => { + constant.try_super_fold_with(self)? + } }) } + + #[inline] + fn try_fold_predicate( + &mut self, + p: ty::Predicate<'tcx>, + ) -> Result<ty::Predicate<'tcx>, Self::Error> { + if p.allow_normalization() && needs_normalization(&p, self.param_env.reveal()) { + p.try_super_fold_with(self) + } else { + Ok(p) + } + } } diff --git a/compiler/rustc_trait_selection/src/traits/query/type_op/custom.rs b/compiler/rustc_trait_selection/src/traits/query/type_op/custom.rs index c99564936..18988861a 100644 --- a/compiler/rustc_trait_selection/src/traits/query/type_op/custom.rs +++ b/compiler/rustc_trait_selection/src/traits/query/type_op/custom.rs @@ -1,11 +1,9 @@ use crate::infer::canonical::query_response; use crate::infer::{InferCtxt, InferOk}; -use crate::traits::engine::TraitEngineExt as _; +use crate::traits; use crate::traits::query::type_op::TypeOpOutput; use crate::traits::query::Fallible; -use crate::traits::TraitEngine; use rustc_infer::infer::region_constraints::RegionConstraintData; -use rustc_infer::traits::TraitEngineExt as _; use rustc_span::source_map::DUMMY_SP; use std::fmt; @@ -25,7 +23,7 @@ impl<F, G> CustomTypeOp<F, G> { } } -impl<'tcx, F, R, G> super::TypeOp<'tcx> for CustomTypeOp<F, G> +impl<'tcx, F, R: fmt::Debug, G> super::TypeOp<'tcx> for CustomTypeOp<F, G> where F: for<'a, 'cx> FnOnce(&'a InferCtxt<'cx, 'tcx>) -> Fallible<InferOk<'tcx, R>>, G: Fn() -> String, @@ -62,8 +60,6 @@ pub fn scrape_region_constraints<'tcx, Op: super::TypeOp<'tcx, Output = R>, R>( infcx: &InferCtxt<'_, 'tcx>, op: impl FnOnce() -> Fallible<InferOk<'tcx, R>>, ) -> Fallible<(TypeOpOutput<'tcx, Op>, RegionConstraintData<'tcx>)> { - let mut fulfill_cx = <dyn TraitEngine<'_>>::new(infcx.tcx); - // During NLL, we expect that nobody will register region // obligations **except** as part of a custom type op (and, at the // end of each custom type op, we scrape out the region @@ -77,8 +73,7 @@ pub fn scrape_region_constraints<'tcx, Op: super::TypeOp<'tcx, Output = R>, R>( ); let InferOk { value, obligations } = infcx.commit_if_ok(|_| op())?; - fulfill_cx.register_predicate_obligations(infcx, obligations); - let errors = fulfill_cx.select_all_or_error(infcx); + let errors = traits::fully_solve_obligations(infcx, obligations); if !errors.is_empty() { infcx.tcx.sess.diagnostic().delay_span_bug( DUMMY_SP, @@ -94,8 +89,8 @@ pub fn scrape_region_constraints<'tcx, Op: super::TypeOp<'tcx, Output = R>, R>( infcx.tcx, region_obligations .iter() - .map(|r_o| (r_o.sup_type, r_o.sub_region)) - .map(|(ty, r)| (infcx.resolve_vars_if_possible(ty), r)), + .map(|r_o| (r_o.sup_type, r_o.sub_region, r_o.origin.to_constraint_category())) + .map(|(ty, r, cc)| (infcx.resolve_vars_if_possible(ty), r, cc)), ®ion_constraint_data, ); diff --git a/compiler/rustc_trait_selection/src/traits/query/type_op/mod.rs b/compiler/rustc_trait_selection/src/traits/query/type_op/mod.rs index 578e1d00c..8a7916570 100644 --- a/compiler/rustc_trait_selection/src/traits/query/type_op/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/query/type_op/mod.rs @@ -26,7 +26,7 @@ pub use rustc_middle::traits::query::type_op::*; /// extract out the resulting region constraints (or an error if it /// cannot be completed). pub trait TypeOp<'tcx>: Sized + fmt::Debug { - type Output; + type Output: fmt::Debug; type ErrorInfo; /// Processes the operation and all resulting obligations, 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 a60ce0f34..a80527f63 100644 --- a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs +++ b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs @@ -8,7 +8,7 @@ use hir::LangItem; use rustc_hir as hir; use rustc_hir::def_id::DefId; -use rustc_infer::traits::TraitEngine; +use rustc_infer::traits::ObligationCause; use rustc_infer::traits::{Obligation, SelectionError, TraitObligation}; use rustc_lint_defs::builtin::DEREF_INTO_DYN_SUPERTRAIT; use rustc_middle::ty::print::with_no_trimmed_paths; @@ -28,7 +28,7 @@ use super::SelectionCandidate::{self, *}; use super::{EvaluatedCandidate, SelectionCandidateSet, SelectionContext, TraitObligationStack}; impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { - #[instrument(level = "debug", skip(self))] + #[instrument(level = "debug", skip(self), ret)] pub(super) fn candidate_from_obligation<'o>( &mut self, stack: &TraitObligationStack<'o, 'tcx>, @@ -48,7 +48,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { if let Some(c) = self.check_candidate_cache(stack.obligation.param_env, cache_fresh_trait_pred) { - debug!(candidate = ?c, "CACHE HIT"); + debug!("CACHE HIT"); return c; } @@ -61,7 +61,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { let (candidate, dep_node) = self.in_task(|this| this.candidate_from_obligation_no_cache(stack)); - debug!(?candidate, "CACHE MISS"); + debug!("CACHE MISS"); self.insert_candidate_cache( stack.obligation.param_env, cache_fresh_trait_pred, @@ -75,7 +75,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { &mut self, stack: &TraitObligationStack<'o, 'tcx>, ) -> SelectionResult<'tcx, SelectionCandidate<'tcx>> { - if let Some(conflict) = self.is_knowable(stack) { + if let Err(conflict) = self.is_knowable(stack) { debug!("coherence stage: not knowable"); if self.intercrate_ambiguity_causes.is_some() { debug!("evaluate_stack: intercrate_ambiguity_causes is some"); @@ -309,6 +309,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { // User-defined transmutability impls are permitted. self.assemble_candidates_from_impls(obligation, &mut candidates); self.assemble_candidates_for_transmutability(obligation, &mut candidates); + } else if lang_items.tuple_trait() == Some(def_id) { + self.assemble_candidate_for_tuple(obligation, &mut candidates); } else { if lang_items.clone_trait() == Some(def_id) { // Same builtin conditions as `Copy`, i.e., every type which has builtin support @@ -337,7 +339,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { Ok(candidates) } - #[tracing::instrument(level = "debug", skip(self, candidates))] + #[instrument(level = "debug", skip(self, candidates))] fn assemble_candidates_from_projected_tys( &mut self, obligation: &TraitObligation<'tcx>, @@ -367,7 +369,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { /// supplied to find out whether it is listed among them. /// /// Never affects the inference environment. - #[tracing::instrument(level = "debug", skip(self, stack, candidates))] + #[instrument(level = "debug", skip(self, stack, candidates))] fn assemble_candidates_from_caller_bounds<'o>( &mut self, stack: &TraitObligationStack<'o, 'tcx>, @@ -706,8 +708,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { fn need_migrate_deref_output_trait_object( &mut self, ty: Ty<'tcx>, - cause: &traits::ObligationCause<'tcx>, param_env: ty::ParamEnv<'tcx>, + cause: &ObligationCause<'tcx>, ) -> Option<(Ty<'tcx>, DefId)> { let tcx = self.tcx(); if tcx.features().trait_upcasting { @@ -729,24 +731,27 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { return None; } - let mut fulfillcx = traits::FulfillmentContext::new_in_snapshot(); - let normalized_ty = fulfillcx.normalize_projection_type( - &self.infcx, + let ty = traits::normalize_projection_type( + self, param_env, ty::ProjectionTy { item_def_id: tcx.lang_items().deref_target()?, substs: trait_ref.substs, }, cause.clone(), - ); - - let ty::Dynamic(data, ..) = normalized_ty.kind() else { - return None; - }; - - let def_id = data.principal_def_id()?; - - return Some((normalized_ty, def_id)); + 0, + // We're *intentionally* throwing these away, + // since we don't actually use them. + &mut vec![], + ) + .ty() + .unwrap(); + + if let ty::Dynamic(data, ..) = ty.kind() { + Some((ty, data.principal_def_id()?)) + } else { + None + } } /// Searches for unsizing that might apply to `obligation`. @@ -809,8 +814,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { if let Some((deref_output_ty, deref_output_trait_did)) = self .need_migrate_deref_output_trait_object( source, - &obligation.cause, obligation.param_env, + &obligation.cause, ) { if deref_output_trait_did == target_trait_did { @@ -877,7 +882,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { }; } - #[tracing::instrument(level = "debug", skip(self, obligation, candidates))] + #[instrument(level = "debug", skip(self, obligation, candidates))] fn assemble_candidates_for_transmutability( &mut self, obligation: &TraitObligation<'tcx>, @@ -895,7 +900,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { candidates.vec.push(TransmutabilityCandidate); } - #[tracing::instrument(level = "debug", skip(self, obligation, candidates))] + #[instrument(level = "debug", skip(self, obligation, candidates))] fn assemble_candidates_for_trait_alias( &mut self, obligation: &TraitObligation<'tcx>, @@ -914,7 +919,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { /// Assembles the trait which are built-in to the language itself: /// `Copy`, `Clone` and `Sized`. - #[tracing::instrument(level = "debug", skip(self, candidates))] + #[instrument(level = "debug", skip(self, candidates))] fn assemble_builtin_bound_candidates( &mut self, conditions: BuiltinImplConditions<'tcx>, @@ -1006,4 +1011,46 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { } } } + + fn assemble_candidate_for_tuple( + &mut self, + obligation: &TraitObligation<'tcx>, + candidates: &mut SelectionCandidateSet<'tcx>, + ) { + let self_ty = self.infcx().shallow_resolve(obligation.self_ty().skip_binder()); + match self_ty.kind() { + ty::Tuple(_) => { + candidates.vec.push(TupleCandidate); + } + ty::Infer(ty::TyVar(_)) => { + candidates.ambiguous = true; + } + ty::Bool + | ty::Char + | ty::Int(_) + | ty::Uint(_) + | ty::Float(_) + | ty::Adt(_, _) + | ty::Foreign(_) + | ty::Str + | ty::Array(_, _) + | ty::Slice(_) + | ty::RawPtr(_) + | ty::Ref(_, _, _) + | ty::FnDef(_, _) + | ty::FnPtr(_) + | ty::Dynamic(_, _, _) + | ty::Closure(_, _) + | ty::Generator(_, _, _) + | ty::GeneratorWitness(_) + | ty::Never + | ty::Projection(_) + | ty::Opaque(_, _) + | ty::Param(_) + | ty::Bound(_, _) + | ty::Error(_) + | ty::Infer(_) + | ty::Placeholder(_) => {} + } + } } diff --git a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs index 2a1099fc8..d1deef784 100644 --- a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs +++ b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs @@ -126,6 +126,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { let data = self.confirm_const_destruct_candidate(obligation, def_id)?; ImplSource::ConstDestruct(data) } + + TupleCandidate => ImplSource::Tuple, }; if !obligation.predicate.is_const_if_const() { @@ -279,29 +281,17 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { let predicate = obligation.predicate; let type_at = |i| predicate.map_bound(|p| p.trait_ref.substs.type_at(i)); - let bool_at = |i| { - predicate - .skip_binder() - .trait_ref - .substs - .const_at(i) - .try_eval_bool(self.tcx(), obligation.param_env) - .unwrap_or(true) - }; + let const_at = |i| predicate.skip_binder().trait_ref.substs.const_at(i); let src_and_dst = predicate.map_bound(|p| rustc_transmute::Types { - src: p.trait_ref.substs.type_at(1), dst: p.trait_ref.substs.type_at(0), + src: p.trait_ref.substs.type_at(1), }); let scope = type_at(2).skip_binder(); - let assume = rustc_transmute::Assume { - alignment: bool_at(3), - lifetimes: bool_at(4), - validity: bool_at(5), - visibility: bool_at(6), - }; + let assume = + rustc_transmute::Assume::from_const(self.infcx.tcx, obligation.param_env, const_at(3)); let cause = obligation.cause.clone(); @@ -794,7 +784,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { let upcast_trait_ref; match (source.kind(), target.kind()) { // TraitA+Kx+'a -> TraitB+Ky+'b (trait upcasting coercion). - (&ty::Dynamic(ref data_a, r_a), &ty::Dynamic(ref data_b, r_b)) => { + (&ty::Dynamic(ref data_a, r_a, repr_a), &ty::Dynamic(ref data_b, r_b, repr_b)) + if repr_a == repr_b => + { // See `assemble_candidates_for_unsizing` for more info. // We already checked the compatibility of auto traits within `assemble_candidates_for_unsizing`. let principal_a = data_a.principal().unwrap(); @@ -820,7 +812,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { .map(ty::Binder::dummy), ); let existential_predicates = tcx.mk_poly_existential_predicates(iter); - let source_trait = tcx.mk_dynamic(existential_predicates, r_b); + let source_trait = tcx.mk_dynamic(existential_predicates, r_b, repr_b); // Require that the traits involved in this upcast are **equal**; // only the **lifetime bound** is changed. @@ -898,7 +890,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { let mut nested = vec![]; match (source.kind(), target.kind()) { // Trait+Kx+'a -> Trait+Ky+'b (auto traits and lifetime subtyping). - (&ty::Dynamic(ref data_a, r_a), &ty::Dynamic(ref data_b, r_b)) => { + (&ty::Dynamic(ref data_a, r_a, ty::Dyn), &ty::Dynamic(ref data_b, r_b, ty::Dyn)) => { // See `assemble_candidates_for_unsizing` for more info. // We already checked the compatibility of auto traits within `assemble_candidates_for_unsizing`. let iter = data_a @@ -917,7 +909,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { .map(ty::Binder::dummy), ); let existential_predicates = tcx.mk_poly_existential_predicates(iter); - let source_trait = tcx.mk_dynamic(existential_predicates, r_b); + let source_trait = tcx.mk_dynamic(existential_predicates, r_b, ty::Dyn); // Require that the traits involved in this upcast are **equal**; // only the **lifetime bound** is changed. @@ -944,7 +936,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { } // `T` -> `Trait` - (_, &ty::Dynamic(ref data, r)) => { + (_, &ty::Dynamic(ref data, r, ty::Dyn)) => { let mut object_dids = data.auto_traits().chain(data.principal_def_id()); if let Some(did) = object_dids.find(|did| !tcx.is_object_safe(*did)) { return Err(TraitNotObjectSafe(did)); @@ -1047,9 +1039,25 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { return Err(Unimplemented); } - // Extract `TailField<T>` and `TailField<U>` from `Struct<T>` and `Struct<U>`. - let source_tail = tail_field_ty.subst(tcx, substs_a); - let target_tail = tail_field_ty.subst(tcx, substs_b); + // Extract `TailField<T>` and `TailField<U>` from `Struct<T>` and `Struct<U>`, + // normalizing in the process, since `type_of` returns something directly from + // astconv (which means it's un-normalized). + let source_tail = normalize_with_depth_to( + self, + obligation.param_env, + obligation.cause.clone(), + obligation.recursion_depth + 1, + tail_field_ty.subst(tcx, substs_a), + &mut nested, + ); + let target_tail = normalize_with_depth_to( + self, + obligation.param_env, + obligation.cause.clone(), + obligation.recursion_depth + 1, + tail_field_ty.subst(tcx, substs_b), + &mut nested, + ); // Check that the source struct with the target's // unsizing parameters is equal to the target. diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs index c01ac1979..75bd2c89f 100644 --- a/compiler/rustc_trait_selection/src/traits/select/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs @@ -295,7 +295,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { /// Attempts to satisfy the obligation. If successful, this will affect the surrounding /// type environment by performing unification. - #[instrument(level = "debug", skip(self))] + #[instrument(level = "debug", skip(self), ret)] pub fn select( &mut self, obligation: &TraitObligation<'tcx>, @@ -325,10 +325,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { Err(SelectionError::Overflow(OverflowError::Canonical)) } Err(e) => Err(e), - Ok(candidate) => { - debug!(?candidate, "confirmed"); - Ok(Some(candidate)) - } + Ok(candidate) => Ok(Some(candidate)), } } @@ -435,6 +432,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { level = "debug", skip(self, previous_stack), fields(previous_stack = ?previous_stack.head()) + ret, )] fn evaluate_predicate_recursively<'o>( &mut self, @@ -450,7 +448,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { None => self.check_recursion_limit(&obligation, &obligation)?, } - let result = ensure_sufficient_stack(|| { + ensure_sufficient_stack(|| { let bound_predicate = obligation.predicate.kind(); match bound_predicate.skip_binder() { ty::PredicateKind::Trait(t) => { @@ -464,15 +462,15 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { let p = bound_predicate.rebind(p); // Does this code ever run? match self.infcx.subtype_predicate(&obligation.cause, obligation.param_env, p) { - Some(Ok(InferOk { mut obligations, .. })) => { + Ok(Ok(InferOk { mut obligations, .. })) => { self.add_depth(obligations.iter_mut(), obligation.recursion_depth); self.evaluate_predicates_recursively( previous_stack, obligations.into_iter(), ) } - Some(Err(_)) => Ok(EvaluatedToErr), - None => Ok(EvaluatedToAmbig), + Ok(Err(_)) => Ok(EvaluatedToErr), + Err(..) => Ok(EvaluatedToAmbig), } } @@ -480,15 +478,15 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { let p = bound_predicate.rebind(p); // Does this code ever run? match self.infcx.coerce_predicate(&obligation.cause, obligation.param_env, p) { - Some(Ok(InferOk { mut obligations, .. })) => { + Ok(Ok(InferOk { mut obligations, .. })) => { self.add_depth(obligations.iter_mut(), obligation.recursion_depth); self.evaluate_predicates_recursively( previous_stack, obligations.into_iter(), ) } - Some(Err(_)) => Ok(EvaluatedToErr), - None => Ok(EvaluatedToAmbig), + Ok(Err(_)) => Ok(EvaluatedToErr), + Err(..) => Ok(EvaluatedToAmbig), } } @@ -701,11 +699,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { if let (ty::ConstKind::Unevaluated(a), ty::ConstKind::Unevaluated(b)) = (c1.kind(), c2.kind()) { - if self.infcx.try_unify_abstract_consts( - a.shrink(), - b.shrink(), - obligation.param_env, - ) { + if self.infcx.try_unify_abstract_consts(a, b, obligation.param_env) { return Ok(EvaluatedToOk); } } @@ -760,14 +754,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { bug!("TypeWellFormedFromEnv is only used for chalk") } } - }); - - debug!("finished: {:?} from {:?}", result, obligation); - - result + }) } - #[instrument(skip(self, previous_stack), level = "debug")] + #[instrument(skip(self, previous_stack), level = "debug", ret)] fn evaluate_trait_predicate_recursively<'o>( &mut self, previous_stack: TraitObligationStackList<'o, 'tcx>, @@ -798,12 +788,12 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { // If a trait predicate is in the (local or global) evaluation cache, // then we know it holds without cycles. if let Some(result) = self.check_evaluation_cache(param_env, fresh_trait_pred) { - debug!(?result, "CACHE HIT"); + debug!("CACHE HIT"); return Ok(result); } if let Some(result) = stack.cache().get_provisional(fresh_trait_pred) { - debug!(?result, "PROVISIONAL CACHE HIT"); + debug!("PROVISIONAL CACHE HIT"); stack.update_reached_depth(result.reached_depth); return Ok(result.result); } @@ -826,11 +816,11 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { let reached_depth = stack.reached_depth.get(); if reached_depth >= stack.depth { - debug!(?result, "CACHE MISS"); + debug!("CACHE MISS"); self.insert_evaluation_cache(param_env, fresh_trait_pred, dep_node, result); stack.cache().on_completion(stack.dfn); } else { - debug!(?result, "PROVISIONAL"); + debug!("PROVISIONAL"); debug!( "caching provisionally because {:?} \ is a cycle participant (at depth {}, reached depth {})", @@ -1023,7 +1013,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { #[instrument( level = "debug", skip(self, stack), - fields(depth = stack.obligation.recursion_depth) + fields(depth = stack.obligation.recursion_depth), + ret )] fn evaluate_candidate<'o>( &mut self, @@ -1056,7 +1047,6 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { result = result.max(EvaluatedToOkModuloRegions); } - debug!(?result); Ok(result) } @@ -1265,11 +1255,11 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { Ok(Some(candidate)) } - fn is_knowable<'o>(&mut self, stack: &TraitObligationStack<'o, 'tcx>) -> Option<Conflict> { + fn is_knowable<'o>(&mut self, stack: &TraitObligationStack<'o, 'tcx>) -> Result<(), Conflict> { debug!("is_knowable(intercrate={:?})", self.intercrate); if !self.intercrate || stack.obligation.polarity() == ty::ImplPolarity::Negative { - return None; + return Ok(()); } let obligation = &stack.obligation; @@ -1405,7 +1395,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { /// 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))] + #[instrument(level = "debug", skip(self), ret)] fn match_projection_obligation_against_definition_bounds( &mut self, obligation: &TraitObligation<'tcx>, @@ -1435,7 +1425,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { // unnecessary ambiguity. let mut distinct_normalized_bounds = FxHashSet::default(); - let matching_bounds = bounds + bounds .iter() .enumerate() .filter_map(|(idx, bound)| { @@ -1462,10 +1452,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { } None }) - .collect(); - - debug!(?matching_bounds); - matching_bounds + .collect() } /// Equates the trait in `obligation` with trait bound. If the two traits @@ -1618,7 +1605,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { }; // (*) Prefer `BuiltinCandidate { has_nested: false }`, `PointeeCandidate`, - // `DiscriminantKindCandidate`, and `ConstDestructCandidate` to anything else. + // `DiscriminantKindCandidate`, `ConstDestructCandidate`, and `TupleCandidate` + // to anything else. // // This is a fix for #53123 and prevents winnowing from accidentally extending the // lifetime of a variable. @@ -1638,7 +1626,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { BuiltinCandidate { has_nested: false } | DiscriminantKindCandidate | PointeeCandidate - | ConstDestructCandidate(_), + | ConstDestructCandidate(_) + | TupleCandidate, _, ) => true, ( @@ -1646,7 +1635,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { BuiltinCandidate { has_nested: false } | DiscriminantKindCandidate | PointeeCandidate - | ConstDestructCandidate(_), + | ConstDestructCandidate(_) + | TupleCandidate, ) => false, (ParamCandidate(other), ParamCandidate(victim)) => { @@ -1871,6 +1861,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { | ty::Array(..) | ty::Closure(..) | ty::Never + | ty::Dynamic(_, _, ty::DynStar) | ty::Error(_) => { // safe for everything Where(ty::Binder::dummy(Vec::new())) @@ -1937,8 +1928,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { ty::Dynamic(..) | ty::Str | ty::Slice(..) - | ty::Generator(..) - | ty::GeneratorWitness(..) + | ty::Generator(_, _, hir::Movability::Static) | ty::Foreign(..) | ty::Ref(_, _, hir::Mutability::Mut) => None, @@ -1947,6 +1937,43 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { Where(obligation.predicate.rebind(tys.iter().collect())) } + ty::Generator(_, substs, hir::Movability::Movable) => { + if self.tcx().features().generator_clone { + let resolved_upvars = + self.infcx.shallow_resolve(substs.as_generator().tupled_upvars_ty()); + let resolved_witness = + self.infcx.shallow_resolve(substs.as_generator().witness()); + if resolved_upvars.is_ty_var() || resolved_witness.is_ty_var() { + // Not yet resolved. + Ambiguous + } else { + let all = substs + .as_generator() + .upvar_tys() + .chain(iter::once(substs.as_generator().witness())) + .collect::<Vec<_>>(); + Where(obligation.predicate.rebind(all)) + } + } else { + None + } + } + + ty::GeneratorWitness(binder) => { + let witness_tys = binder.skip_binder(); + for witness_ty in witness_tys.iter() { + let resolved = self.infcx.shallow_resolve(witness_ty); + if resolved.is_ty_var() { + return Ambiguous; + } + } + // (*) binder moved here + let all_vars = self.tcx().mk_bound_variable_kinds( + obligation.predicate.bound_vars().iter().chain(binder.bound_vars().iter()), + ); + Where(ty::Binder::bind_with_vars(witness_tys.to_vec(), all_vars)) + } + ty::Closure(_, substs) => { // (*) binder moved here let ty = self.infcx.shallow_resolve(substs.as_closure().tupled_upvars_ty()); @@ -2153,7 +2180,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { } } - #[tracing::instrument(level = "debug", skip(self))] + #[instrument(level = "debug", skip(self), ret)] fn match_impl( &mut self, impl_def_id: DefId, @@ -2194,17 +2221,16 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { .at(&cause, obligation.param_env) .define_opaque_types(false) .eq(placeholder_obligation_trait_ref, impl_trait_ref) - .map_err(|e| debug!("match_impl: failed eq_trait_refs due to `{}`", e))?; + .map_err(|e| debug!("match_impl: failed eq_trait_refs due to `{e}`"))?; nested_obligations.extend(obligations); if !self.intercrate && self.tcx().impl_polarity(impl_def_id) == ty::ImplPolarity::Reservation { - debug!("match_impl: reservation impls only apply in intercrate mode"); + debug!("reservation impls only apply in intercrate mode"); return Err(()); } - debug!(?impl_substs, ?nested_obligations, "match_impl: success"); Ok(Normalized { value: impl_substs, obligations: nested_obligations }) } @@ -2335,7 +2361,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { /// impl or trait. The obligations are substituted and fully /// normalized. This is used when confirming an impl or default /// impl. - #[tracing::instrument(level = "debug", skip(self, cause, param_env))] + #[instrument(level = "debug", skip(self, cause, param_env))] fn impl_or_trait_obligations( &mut self, cause: &ObligationCause<'tcx>, diff --git a/compiler/rustc_trait_selection/src/traits/specialize/mod.rs b/compiler/rustc_trait_selection/src/traits/specialize/mod.rs index 6223c5ea3..7d299e30a 100644 --- a/compiler/rustc_trait_selection/src/traits/specialize/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/specialize/mod.rs @@ -12,11 +12,10 @@ pub mod specialization_graph; use specialization_graph::GraphExt; +use crate::errors::NegativePositiveConflict; use crate::infer::{InferCtxt, InferOk, TyCtxtInferExt}; use crate::traits::select::IntercrateAmbiguityCause; -use crate::traits::{ - self, coherence, FutureCompatOverlapErrorKind, ObligationCause, TraitEngine, TraitEngineExt, -}; +use crate::traits::{self, coherence, FutureCompatOverlapErrorKind, ObligationCause}; use rustc_data_structures::fx::{FxHashSet, FxIndexSet}; use rustc_errors::{struct_span_err, EmissionGuarantee, LintDiagnosticBuilder}; use rustc_hir::def_id::{DefId, LocalDefId}; @@ -26,8 +25,8 @@ use rustc_session::lint::builtin::COHERENCE_LEAK_CHECK; use rustc_session::lint::builtin::ORDER_DEPENDENT_TRAIT_OBJECTS; use rustc_span::{Span, DUMMY_SP}; +use super::util; use super::SelectionContext; -use super::{util, FulfillmentContext}; /// Information pertinent to an overlapping impl error. #[derive(Debug)] @@ -153,7 +152,6 @@ pub(super) fn specializes(tcx: TyCtxt<'_>, (impl1_def_id, impl2_def_id): (DefId, tcx.infer_ctxt().enter(|infcx| { let impl1_trait_ref = match traits::fully_normalize( &infcx, - FulfillmentContext::new(), ObligationCause::dummy(), penv, impl1_trait_ref, @@ -211,11 +209,8 @@ fn fulfill_implication<'a, 'tcx>( // (which are packed up in penv) infcx.save_and_restore_in_snapshot_flag(|infcx| { - let mut fulfill_cx = <dyn TraitEngine<'tcx>>::new(infcx.tcx); - for oblig in obligations.chain(more_obligations) { - fulfill_cx.register_predicate_obligation(&infcx, oblig); - } - match fulfill_cx.select_all_or_error(infcx).as_slice() { + let errors = traits::fully_solve_obligations(&infcx, obligations.chain(more_obligations)); + match &errors[..] { [] => { debug!( "fulfill_implication: an impl for {:?} specializes {:?}", @@ -333,35 +328,13 @@ fn report_negative_positive_conflict( positive_impl_def_id: DefId, sg: &mut specialization_graph::Graph, ) { - let impl_span = tcx.def_span(local_impl_def_id); - - let mut err = struct_span_err!( - tcx.sess, - impl_span, - E0751, - "found both positive and negative implementation of trait `{}`{}:", - overlap.trait_desc, - overlap.self_desc.clone().map_or_else(String::new, |ty| format!(" for type `{}`", ty)) - ); - - match tcx.span_of_impl(negative_impl_def_id) { - Ok(span) => { - err.span_label(span, "negative implementation here"); - } - Err(cname) => { - err.note(&format!("negative implementation in crate `{}`", cname)); - } - } - - match tcx.span_of_impl(positive_impl_def_id) { - Ok(span) => { - err.span_label(span, "positive implementation here"); - } - Err(cname) => { - err.note(&format!("positive implementation in crate `{}`", cname)); - } - } - + let mut err = tcx.sess.create_err(NegativePositiveConflict { + impl_span: tcx.def_span(local_impl_def_id), + trait_desc: &overlap.trait_desc, + self_desc: &overlap.self_desc, + negative_impl_span: tcx.span_of_impl(negative_impl_def_id), + positive_impl_span: tcx.span_of_impl(positive_impl_def_id), + }); sg.has_errored = Some(err.emit()); } diff --git a/compiler/rustc_trait_selection/src/traits/util.rs b/compiler/rustc_trait_selection/src/traits/util.rs index d25006016..0f5dff01c 100644 --- a/compiler/rustc_trait_selection/src/traits/util.rs +++ b/compiler/rustc_trait_selection/src/traits/util.rs @@ -11,8 +11,6 @@ use rustc_middle::ty::{self, ImplSubject, ToPredicate, Ty, TyCtxt, TypeVisitable use super::{Normalized, Obligation, ObligationCause, PredicateObligation, SelectionContext}; pub use rustc_infer::traits::{self, util::*}; -use std::iter; - /////////////////////////////////////////////////////////////////////////// // `TraitAliasExpander` iterator /////////////////////////////////////////////////////////////////////////// @@ -210,7 +208,7 @@ pub fn impl_subject_and_oblig<'a, 'tcx>( let Normalized { value: predicates, obligations: normalization_obligations2 } = super::normalize(selcx, param_env, ObligationCause::dummy(), predicates); let impl_obligations = - predicates_for_generics(ObligationCause::dummy(), 0, param_env, predicates); + super::predicates_for_generics(|_, _| ObligationCause::dummy(), param_env, predicates); let impl_obligations = impl_obligations .chain(normalization_obligations1.into_iter()) @@ -219,27 +217,6 @@ pub fn impl_subject_and_oblig<'a, 'tcx>( (subject, impl_obligations) } -pub fn predicates_for_generics<'tcx>( - cause: ObligationCause<'tcx>, - recursion_depth: usize, - param_env: ty::ParamEnv<'tcx>, - generic_bounds: ty::InstantiatedPredicates<'tcx>, -) -> impl Iterator<Item = PredicateObligation<'tcx>> { - debug!("predicates_for_generics(generic_bounds={:?})", generic_bounds); - - iter::zip(generic_bounds.predicates, generic_bounds.spans).map(move |(predicate, span)| { - let cause = match *cause.code() { - traits::ItemObligation(def_id) if !span.is_dummy() => traits::ObligationCause::new( - cause.span, - cause.body_id, - traits::BindingObligation(def_id, span), - ), - _ => cause.clone(), - }; - Obligation { cause, recursion_depth, param_env, predicate } - }) -} - pub fn predicate_for_trait_ref<'tcx>( tcx: TyCtxt<'tcx>, cause: ObligationCause<'tcx>, diff --git a/compiler/rustc_trait_selection/src/traits/wf.rs b/compiler/rustc_trait_selection/src/traits/wf.rs index 414857f0a..5ea28fb47 100644 --- a/compiler/rustc_trait_selection/src/traits/wf.rs +++ b/compiler/rustc_trait_selection/src/traits/wf.rs @@ -31,9 +31,9 @@ pub fn obligations<'a, 'tcx>( if resolved_ty == ty { // No progress, bail out to prevent "livelock". return None; + } else { + resolved_ty } - - resolved_ty } _ => ty, } @@ -41,16 +41,14 @@ pub fn obligations<'a, 'tcx>( } GenericArgKind::Const(ct) => { match ct.kind() { - ty::ConstKind::Infer(infer) => { - let resolved = infcx.shallow_resolve(infer); - if resolved == infer { + ty::ConstKind::Infer(_) => { + let resolved = infcx.shallow_resolve(ct); + if resolved == ct { // No progress. return None; + } else { + resolved } - - infcx - .tcx - .mk_const(ty::ConstS { kind: ty::ConstKind::Infer(resolved), ty: ct.ty() }) } _ => ct, } @@ -103,6 +101,7 @@ pub fn trait_obligations<'a, 'tcx>( wf.normalize(infcx) } +#[instrument(skip(infcx), ret)] pub fn predicate_obligations<'a, 'tcx>( infcx: &InferCtxt<'a, 'tcx>, param_env: ty::ParamEnv<'tcx>, @@ -131,9 +130,9 @@ pub fn predicate_obligations<'a, 'tcx>( } ty::PredicateKind::Projection(t) => { wf.compute_projection(t.projection_ty); - wf.compute(match t.term { - ty::Term::Ty(ty) => ty.into(), - ty::Term::Const(c) => c.into(), + wf.compute(match t.term.unpack() { + ty::TermKind::Ty(ty) => ty.into(), + ty::TermKind::Const(c) => c.into(), }) } ty::PredicateKind::WellFormed(arg) => { @@ -436,11 +435,13 @@ impl<'tcx> WfPredicates<'tcx> { } /// Pushes all the predicates needed to validate that `ty` is WF into `out`. + #[instrument(level = "debug", skip(self))] fn compute(&mut self, arg: GenericArg<'tcx>) { let mut walker = arg.walk(); let param_env = self.param_env; let depth = self.recursion_depth; while let Some(arg) = walker.next() { + debug!(?arg, ?self.out); let ty = match arg.unpack() { GenericArgKind::Type(ty) => ty, @@ -455,7 +456,7 @@ impl<'tcx> WfPredicates<'tcx> { self.out.extend(obligations); let predicate = - ty::Binder::dummy(ty::PredicateKind::ConstEvaluatable(uv.shrink())) + ty::Binder::dummy(ty::PredicateKind::ConstEvaluatable(uv)) .to_predicate(self.tcx()); let cause = self.cause(traits::WellFormed(None)); self.out.push(traits::Obligation::with_depth( @@ -490,6 +491,8 @@ impl<'tcx> WfPredicates<'tcx> { } }; + debug!("wf bounds for ty={:?} ty.kind={:#?}", ty, ty.kind()); + match *ty.kind() { ty::Bool | ty::Char @@ -636,7 +639,7 @@ impl<'tcx> WfPredicates<'tcx> { } } - ty::Dynamic(data, r) => { + ty::Dynamic(data, r, _) => { // WfObject // // Here, we defer WF checking due to higher-ranked @@ -688,6 +691,8 @@ impl<'tcx> WfPredicates<'tcx> { )); } } + + debug!(?self.out); } } @@ -713,7 +718,7 @@ impl<'tcx> WfPredicates<'tcx> { iter::zip(iter::zip(predicates.predicates, predicates.spans), origins.into_iter().rev()) .map(|((mut pred, span), origin_def_id)| { let code = if span.is_dummy() { - traits::MiscObligation + traits::ItemObligation(origin_def_id) } else { traits::BindingObligation(origin_def_id, span) }; @@ -843,7 +848,7 @@ pub fn object_region_bounds<'tcx>( /// /// Requires that trait definitions have been processed so that we can /// elaborate predicates and walk supertraits. -#[instrument(skip(tcx, predicates), level = "debug")] +#[instrument(skip(tcx, predicates), level = "debug", ret)] pub(crate) fn required_region_bounds<'tcx>( tcx: TyCtxt<'tcx>, erased_self_ty: Ty<'tcx>, |