diff options
Diffstat (limited to 'compiler/rustc_hir_analysis/src/check/compare_method.rs')
| -rw-r--r-- | compiler/rustc_hir_analysis/src/check/compare_method.rs | 576 |
1 files changed, 347 insertions, 229 deletions
diff --git a/compiler/rustc_hir_analysis/src/check/compare_method.rs b/compiler/rustc_hir_analysis/src/check/compare_method.rs index 32f66b06f..db150ebf0 100644 --- a/compiler/rustc_hir_analysis/src/check/compare_method.rs +++ b/compiler/rustc_hir_analysis/src/check/compare_method.rs @@ -1,7 +1,7 @@ use super::potentially_plural_count; use crate::errors::LifetimesOrBoundsMismatchOnTrait; use hir::def_id::{DefId, LocalDefId}; -use rustc_data_structures::fx::{FxHashMap, FxHashSet}; +use rustc_data_structures::fx::{FxHashMap, FxIndexSet}; use rustc_errors::{pluralize, struct_span_err, Applicability, DiagnosticId, ErrorGuaranteed}; use rustc_hir as hir; use rustc_hir::def::{DefKind, Res}; @@ -9,13 +9,12 @@ use rustc_hir::intravisit; use rustc_hir::{GenericParamKind, ImplItemKind, TraitItemKind}; use rustc_infer::infer::outlives::env::OutlivesEnvironment; use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind}; -use rustc_infer::infer::{self, TyCtxtInferExt}; +use rustc_infer::infer::{self, InferCtxt, TyCtxtInferExt}; use rustc_infer::traits::util; use rustc_middle::ty::error::{ExpectedFound, TypeError}; use rustc_middle::ty::util::ExplicitSelf; -use rustc_middle::ty::InternalSubsts; use rustc_middle::ty::{ - self, AssocItem, DefIdTree, Ty, TypeFoldable, TypeFolder, TypeSuperFoldable, TypeVisitable, + self, DefIdTree, InternalSubsts, Ty, TypeFoldable, TypeFolder, TypeSuperFoldable, TypeVisitable, }; use rustc_middle::ty::{GenericParamDefKind, ToPredicate, TyCtxt}; use rustc_span::Span; @@ -50,11 +49,11 @@ pub(crate) fn compare_impl_method<'tcx>( return; } - if let Err(_) = compare_number_of_generics(tcx, impl_m, impl_m_span, trait_m, trait_item_span) { + if let Err(_) = compare_number_of_generics(tcx, impl_m, trait_m, trait_item_span, false) { return; } - if let Err(_) = compare_generic_param_kinds(tcx, impl_m, trait_m) { + if let Err(_) = compare_generic_param_kinds(tcx, impl_m, trait_m, false) { return; } @@ -68,8 +67,14 @@ pub(crate) fn compare_impl_method<'tcx>( return; } - if let Err(_) = compare_predicate_entailment(tcx, impl_m, impl_m_span, trait_m, impl_trait_ref) - { + if let Err(_) = compare_predicate_entailment( + tcx, + impl_m, + impl_m_span, + trait_m, + impl_trait_ref, + CheckImpliedWfMode::Check, + ) { return; } } @@ -143,10 +148,11 @@ pub(crate) fn compare_impl_method<'tcx>( #[instrument(level = "debug", skip(tcx, impl_m_span, impl_trait_ref))] fn compare_predicate_entailment<'tcx>( tcx: TyCtxt<'tcx>, - impl_m: &AssocItem, + impl_m: &ty::AssocItem, impl_m_span: Span, - trait_m: &AssocItem, + trait_m: &ty::AssocItem, impl_trait_ref: ty::TraitRef<'tcx>, + check_implied_wf: CheckImpliedWfMode, ) -> Result<(), ErrorGuaranteed> { let trait_to_impl_substs = impl_trait_ref.substs; @@ -156,8 +162,7 @@ fn compare_predicate_entailment<'tcx>( // FIXME(@lcnr): remove that after removing `cause.body_id` from // obligations. let impl_m_hir_id = tcx.hir().local_def_id_to_hir_id(impl_m.def_id.expect_local()); - // We sometimes modify the span further down. - let mut cause = ObligationCause::new( + let cause = ObligationCause::new( impl_m_span, impl_m_hir_id, ObligationCauseCode::CompareImplItemObligation { @@ -175,13 +180,11 @@ fn compare_predicate_entailment<'tcx>( impl_to_placeholder_substs.rebase_onto(tcx, impl_m.container_id(tcx), trait_to_impl_substs); debug!("compare_impl_method: trait_to_placeholder_substs={:?}", trait_to_placeholder_substs); - let impl_m_generics = tcx.generics_of(impl_m.def_id); - let trait_m_generics = tcx.generics_of(trait_m.def_id); let impl_m_predicates = tcx.predicates_of(impl_m.def_id); let trait_m_predicates = tcx.predicates_of(trait_m.def_id); // Check region bounds. - check_region_bounds_on_impl_item(tcx, impl_m, trait_m, &trait_m_generics, &impl_m_generics)?; + check_region_bounds_on_impl_item(tcx, impl_m, trait_m, false)?; // Create obligations for each predicate declared by the impl // definition in the context of the trait's parameter @@ -220,14 +223,11 @@ fn compare_predicate_entailment<'tcx>( debug!("compare_impl_method: caller_bounds={:?}", param_env.caller_bounds()); - let mut selcx = traits::SelectionContext::new(&infcx); let impl_m_own_bounds = impl_m_predicates.instantiate_own(tcx, impl_to_placeholder_substs); for (predicate, span) in iter::zip(impl_m_own_bounds.predicates, impl_m_own_bounds.spans) { let normalize_cause = traits::ObligationCause::misc(span, impl_m_hir_id); - let traits::Normalized { value: predicate, obligations } = - traits::normalize(&mut selcx, param_env, normalize_cause, predicate); + let predicate = ocx.normalize(&normalize_cause, param_env, predicate); - ocx.register_obligations(obligations); let cause = ObligationCause::new( span, impl_m_hir_id, @@ -237,7 +237,7 @@ fn compare_predicate_entailment<'tcx>( kind: impl_m.kind, }, ); - ocx.register_obligation(traits::Obligation::new(cause, param_env, predicate)); + ocx.register_obligation(traits::Obligation::new(tcx, cause, param_env, predicate)); } // We now need to check that the signature of the impl method is @@ -256,17 +256,17 @@ fn compare_predicate_entailment<'tcx>( // Compute placeholder form of impl and trait method tys. let tcx = infcx.tcx; - let mut wf_tys = FxHashSet::default(); + let mut wf_tys = FxIndexSet::default(); - let impl_sig = infcx.replace_bound_vars_with_fresh_vars( + let unnormalized_impl_sig = infcx.replace_bound_vars_with_fresh_vars( impl_m_span, infer::HigherRankedType, tcx.fn_sig(impl_m.def_id), ); + let unnormalized_impl_fty = tcx.mk_fn_ptr(ty::Binder::dummy(unnormalized_impl_sig)); let norm_cause = ObligationCause::misc(impl_m_span, impl_m_hir_id); - let impl_sig = ocx.normalize(norm_cause.clone(), param_env, impl_sig); - let impl_fty = tcx.mk_fn_ptr(ty::Binder::dummy(impl_sig)); + let impl_fty = ocx.normalize(&norm_cause, param_env, unnormalized_impl_fty); debug!("compare_impl_method: impl_fty={:?}", impl_fty); let trait_sig = tcx.bound_fn_sig(trait_m.def_id).subst(tcx, trait_to_placeholder_substs); @@ -276,7 +276,7 @@ fn compare_predicate_entailment<'tcx>( // we have to do this before normalization, since the normalized ty may // not contain the input parameters. See issue #87748. wf_tys.extend(trait_sig.inputs_and_output.iter()); - let trait_sig = ocx.normalize(norm_cause, param_env, trait_sig); + let trait_sig = ocx.normalize(&norm_cause, param_env, trait_sig); // We also have to add the normalized trait signature // as we don't normalize during implied bounds computation. wf_tys.extend(trait_sig.inputs_and_output.iter()); @@ -290,147 +290,126 @@ fn compare_predicate_entailment<'tcx>( // type would be more appropriate. In other places we have a `Vec<Span>` // corresponding to their `Vec<Predicate>`, but we don't have that here. // Fixing this would improve the output of test `issue-83765.rs`. - let mut result = infcx - .at(&cause, param_env) - .sup(trait_fty, impl_fty) - .map(|infer_ok| ocx.register_infer_ok_obligations(infer_ok)); - - // HACK(RPITIT): #101614. When we are trying to infer the hidden types for - // RPITITs, we need to equate the output tys instead of just subtyping. If - // we just use `sup` above, we'll end up `&'static str <: _#1t`, which causes - // us to infer `_#1t = #'_#2r str`, where `'_#2r` is unconstrained, which gets - // fixed up to `ReEmpty`, and which is certainly not what we want. - if trait_fty.has_infer_types() { - result = result.and_then(|()| { - infcx - .at(&cause, param_env) - .eq(trait_sig.output(), impl_sig.output()) - .map(|infer_ok| ocx.register_infer_ok_obligations(infer_ok)) - }); - } + let result = ocx.sup(&cause, param_env, trait_fty, impl_fty); if let Err(terr) = result { - debug!("sub_types failed: impl ty {:?}, trait ty {:?}", impl_fty, trait_fty); - - let (impl_err_span, trait_err_span) = - extract_spans_for_error_reporting(&infcx, terr, &cause, impl_m, trait_m); - - cause.span = impl_err_span; - - let mut diag = struct_span_err!( - tcx.sess, - cause.span(), - E0053, - "method `{}` has an incompatible type for trait", - trait_m.name - ); - match &terr { - TypeError::ArgumentMutability(0) | TypeError::ArgumentSorts(_, 0) - if trait_m.fn_has_self_parameter => - { - let ty = trait_sig.inputs()[0]; - let sugg = match ExplicitSelf::determine(ty, |_| ty == impl_trait_ref.self_ty()) { - ExplicitSelf::ByValue => "self".to_owned(), - ExplicitSelf::ByReference(_, hir::Mutability::Not) => "&self".to_owned(), - ExplicitSelf::ByReference(_, hir::Mutability::Mut) => "&mut self".to_owned(), - _ => format!("self: {ty}"), - }; - - // When the `impl` receiver is an arbitrary self type, like `self: Box<Self>`, the - // span points only at the type `Box<Self`>, but we want to cover the whole - // argument pattern and type. - let span = match tcx.hir().expect_impl_item(impl_m.def_id.expect_local()).kind { - ImplItemKind::Fn(ref sig, body) => tcx - .hir() - .body_param_names(body) - .zip(sig.decl.inputs.iter()) - .map(|(param, ty)| param.span.to(ty.span)) - .next() - .unwrap_or(impl_err_span), - _ => bug!("{:?} is not a method", impl_m), - }; - - diag.span_suggestion( - span, - "change the self-receiver type to match the trait", - sugg, - Applicability::MachineApplicable, - ); - } - TypeError::ArgumentMutability(i) | TypeError::ArgumentSorts(_, i) => { - if trait_sig.inputs().len() == *i { - // Suggestion to change output type. We do not suggest in `async` functions - // to avoid complex logic or incorrect output. - match tcx.hir().expect_impl_item(impl_m.def_id.expect_local()).kind { - ImplItemKind::Fn(ref sig, _) - if sig.header.asyncness == hir::IsAsync::NotAsync => - { - let msg = "change the output type to match the trait"; - let ap = Applicability::MachineApplicable; - match sig.decl.output { - hir::FnRetTy::DefaultReturn(sp) => { - let sugg = format!("-> {} ", trait_sig.output()); - diag.span_suggestion_verbose(sp, msg, sugg, ap); - } - hir::FnRetTy::Return(hir_ty) => { - let sugg = trait_sig.output(); - diag.span_suggestion(hir_ty.span, msg, sugg, ap); - } - }; - } - _ => {} - }; - } else if let Some(trait_ty) = trait_sig.inputs().get(*i) { - diag.span_suggestion( - impl_err_span, - "change the parameter type to match the trait", - trait_ty, - Applicability::MachineApplicable, - ); - } - } - _ => {} - } + debug!(?terr, "sub_types failed: impl ty {:?}, trait ty {:?}", impl_fty, trait_fty); - infcx.err_ctxt().note_type_err( - &mut diag, - &cause, - trait_err_span.map(|sp| (sp, "type in trait".to_owned())), - Some(infer::ValuePairs::Terms(ExpectedFound { - expected: trait_fty.into(), - found: impl_fty.into(), - })), + let emitted = report_trait_method_mismatch( + &infcx, + cause, terr, - false, - false, + (trait_m, trait_fty), + (impl_m, impl_fty), + trait_sig, + impl_trait_ref, ); + return Err(emitted); + } - return Err(diag.emit()); + if check_implied_wf == CheckImpliedWfMode::Check { + // We need to check that the impl's args are well-formed given + // the hybrid param-env (impl + trait method where-clauses). + ocx.register_obligation(traits::Obligation::new( + infcx.tcx, + ObligationCause::dummy(), + param_env, + ty::Binder::dummy(ty::PredicateKind::WellFormed(unnormalized_impl_fty.into())), + )); } + let emit_implied_wf_lint = || { + infcx.tcx.struct_span_lint_hir( + rustc_session::lint::builtin::IMPLIED_BOUNDS_ENTAILMENT, + impl_m_hir_id, + infcx.tcx.def_span(impl_m.def_id), + "impl method assumes more implied bounds than the corresponding trait method", + |lint| lint, + ); + }; // Check that all obligations are satisfied by the implementation's // version. let errors = ocx.select_all_or_error(); if !errors.is_empty() { - let reported = infcx.err_ctxt().report_fulfillment_errors(&errors, None, false); - return Err(reported); + match check_implied_wf { + CheckImpliedWfMode::Check => { + return compare_predicate_entailment( + tcx, + impl_m, + impl_m_span, + trait_m, + impl_trait_ref, + CheckImpliedWfMode::Skip, + ) + .map(|()| { + // If the skip-mode was successful, emit a lint. + emit_implied_wf_lint(); + }); + } + CheckImpliedWfMode::Skip => { + let reported = infcx.err_ctxt().report_fulfillment_errors(&errors, None); + return Err(reported); + } + } } // Finally, resolve all regions. This catches wily misuses of // lifetime parameters. - let outlives_environment = OutlivesEnvironment::with_bounds( + let outlives_env = OutlivesEnvironment::with_bounds( param_env, Some(infcx), - infcx.implied_bounds_tys(param_env, impl_m_hir_id, wf_tys), + infcx.implied_bounds_tys(param_env, impl_m_hir_id, wf_tys.clone()), ); - infcx.check_region_obligations_and_report_errors( - impl_m.def_id.expect_local(), - &outlives_environment, + infcx.process_registered_region_obligations( + outlives_env.region_bound_pairs(), + outlives_env.param_env, ); + let errors = infcx.resolve_regions(&outlives_env); + if !errors.is_empty() { + // FIXME(compiler-errors): This can be simplified when IMPLIED_BOUNDS_ENTAILMENT + // becomes a hard error (i.e. ideally we'd just call `resolve_regions_and_report_errors` + match check_implied_wf { + CheckImpliedWfMode::Check => { + return compare_predicate_entailment( + tcx, + impl_m, + impl_m_span, + trait_m, + impl_trait_ref, + CheckImpliedWfMode::Skip, + ) + .map(|()| { + // If the skip-mode was successful, emit a lint. + emit_implied_wf_lint(); + }); + } + CheckImpliedWfMode::Skip => { + if infcx.tainted_by_errors().is_none() { + infcx.err_ctxt().report_region_errors(impl_m.def_id.expect_local(), &errors); + } + return Err(tcx + .sess + .delay_span_bug(rustc_span::DUMMY_SP, "error should have been emitted")); + } + } + } Ok(()) } +#[derive(Debug, PartialEq, Eq)] +enum CheckImpliedWfMode { + /// Checks implied well-formedness of the impl method. If it fails, we will + /// re-check with `Skip`, and emit a lint if it succeeds. + Check, + /// Skips checking implied well-formedness of the impl method, but will emit + /// a lint if the `compare_predicate_entailment` succeeded. This means that + /// the reason that we had failed earlier during `Check` was due to the impl + /// having stronger requirements than the trait. + Skip, +} + +#[instrument(skip(tcx), level = "debug", ret)] pub fn collect_trait_impl_trait_tys<'tcx>( tcx: TyCtxt<'tcx>, def_id: DefId, @@ -440,6 +419,11 @@ pub fn collect_trait_impl_trait_tys<'tcx>( let impl_trait_ref = tcx.impl_trait_ref(impl_m.impl_container(tcx).unwrap()).unwrap(); let param_env = tcx.param_env(def_id); + // First, check a few of the same thing as `compare_impl_method`, just so we don't ICE during substitutions later. + compare_number_of_generics(tcx, impl_m, trait_m, tcx.hir().span_if_local(impl_m.def_id), true)?; + compare_generic_param_kinds(tcx, impl_m, trait_m, true)?; + check_region_bounds_on_impl_item(tcx, impl_m, trait_m, true)?; + let trait_to_impl_substs = impl_trait_ref.substs; let impl_m_hir_id = tcx.hir().local_def_id_to_hir_id(impl_m.def_id.expect_local()); @@ -464,9 +448,10 @@ pub fn collect_trait_impl_trait_tys<'tcx>( let infcx = &tcx.infer_ctxt().build(); let ocx = ObligationCtxt::new(infcx); + // Normalize the impl signature with fresh variables for lifetime inference. let norm_cause = ObligationCause::misc(return_span, impl_m_hir_id); let impl_sig = ocx.normalize( - norm_cause.clone(), + &norm_cause, param_env, infcx.replace_bound_vars_with_fresh_vars( return_span, @@ -476,6 +461,10 @@ pub fn collect_trait_impl_trait_tys<'tcx>( ); let impl_return_ty = impl_sig.output(); + // Normalize the trait signature with liberated bound vars, passing it through + // the ImplTraitInTraitCollector, which gathers all of the RPITITs and replaces + // them with inference variables. + // We will use these inference variables to collect the hidden types of RPITITs. let mut collector = ImplTraitInTraitCollector::new(&ocx, return_span, param_env, impl_m_hir_id); let unnormalized_trait_sig = tcx .liberate_late_bound_regions( @@ -483,17 +472,15 @@ pub fn collect_trait_impl_trait_tys<'tcx>( tcx.bound_fn_sig(trait_m.def_id).subst(tcx, trait_to_placeholder_substs), ) .fold_with(&mut collector); - let trait_sig = ocx.normalize(norm_cause.clone(), param_env, unnormalized_trait_sig); + let trait_sig = ocx.normalize(&norm_cause, param_env, unnormalized_trait_sig); let trait_return_ty = trait_sig.output(); - let wf_tys = FxHashSet::from_iter( + let wf_tys = FxIndexSet::from_iter( unnormalized_trait_sig.inputs_and_output.iter().chain(trait_sig.inputs_and_output.iter()), ); - match infcx.at(&cause, param_env).eq(trait_return_ty, impl_return_ty) { - Ok(infer::InferOk { value: (), obligations }) => { - ocx.register_obligations(obligations); - } + match ocx.eq(&cause, param_env, trait_return_ty, impl_return_ty) { + Ok(()) => {} Err(terr) => { let mut diag = struct_span_err!( tcx.sess, @@ -521,23 +508,32 @@ pub fn collect_trait_impl_trait_tys<'tcx>( } } + debug!(?trait_sig, ?impl_sig, "equating function signatures"); + + let trait_fty = tcx.mk_fn_ptr(ty::Binder::dummy(trait_sig)); + let impl_fty = tcx.mk_fn_ptr(ty::Binder::dummy(impl_sig)); + // Unify the whole function signature. We need to do this to fully infer // the lifetimes of the return type, but do this after unifying just the // return types, since we want to avoid duplicating errors from // `compare_predicate_entailment`. - match infcx - .at(&cause, param_env) - .eq(tcx.mk_fn_ptr(ty::Binder::dummy(trait_sig)), tcx.mk_fn_ptr(ty::Binder::dummy(impl_sig))) - { - Ok(infer::InferOk { value: (), obligations }) => { - ocx.register_obligations(obligations); - } + match ocx.eq(&cause, param_env, trait_fty, impl_fty) { + Ok(()) => {} Err(terr) => { - let guar = tcx.sess.delay_span_bug( - return_span, - format!("could not unify `{trait_sig}` and `{impl_sig}`: {terr:?}"), + // This function gets called during `compare_predicate_entailment` when normalizing a + // signature that contains RPITIT. When the method signatures don't match, we have to + // emit an error now because `compare_predicate_entailment` will not report the error + // when normalization fails. + let emitted = report_trait_method_mismatch( + infcx, + cause, + terr, + (trait_m, trait_fty), + (impl_m, impl_fty), + trait_sig, + impl_trait_ref, ); - return Err(guar); + return Err(emitted); } } @@ -545,7 +541,7 @@ pub fn collect_trait_impl_trait_tys<'tcx>( // RPITs. let errors = ocx.select_all_or_error(); if !errors.is_empty() { - let reported = infcx.err_ctxt().report_fulfillment_errors(&errors, None, false); + let reported = infcx.err_ctxt().report_fulfillment_errors(&errors, None); return Err(reported); } @@ -597,7 +593,13 @@ pub fn collect_trait_impl_trait_tys<'tcx>( let num_trait_substs = trait_to_impl_substs.len(); let num_impl_substs = tcx.generics_of(impl_m.container_id(tcx)).params.len(); let ty = tcx.fold_regions(ty, |region, _| { - let (ty::ReFree(_) | ty::ReEarlyBound(_)) = region.kind() else { return region; }; + match region.kind() { + // Remap all free regions, which correspond to late-bound regions in the function. + ty::ReFree(_) => {} + // Remap early-bound regions as long as they don't come from the `impl` itself. + ty::ReEarlyBound(ebr) if tcx.parent(ebr.def_id) != impl_m.container_id(tcx) => {} + _ => return region, + } let Some(ty::ReEarlyBound(e)) = map.get(®ion.into()).map(|r| r.expect_region().kind()) else { tcx @@ -618,11 +620,11 @@ pub fn collect_trait_impl_trait_tys<'tcx>( collected_tys.insert(def_id, ty); } Err(err) => { - tcx.sess.delay_span_bug( + let reported = tcx.sess.delay_span_bug( return_span, format!("could not fully resolve: {ty} => {err:?}"), ); - collected_tys.insert(def_id, tcx.ty_error()); + collected_tys.insert(def_id, tcx.ty_error_with_guaranteed(reported)); } } } @@ -675,12 +677,13 @@ impl<'tcx> TypeFolder<'tcx> for ImplTraitInTraitCollector<'_, 'tcx> { for (pred, pred_span) in self.tcx().bound_explicit_item_bounds(proj.item_def_id).subst_iter_copied(self.tcx(), proj.substs) { let pred = pred.fold_with(self); let pred = self.ocx.normalize( - ObligationCause::misc(self.span, self.body_id), + &ObligationCause::misc(self.span, self.body_id), self.param_env, pred, ); self.ocx.register_obligation(traits::Obligation::new( + self.tcx(), ObligationCause::new( self.span, self.body_id, @@ -697,16 +700,121 @@ impl<'tcx> TypeFolder<'tcx> for ImplTraitInTraitCollector<'_, 'tcx> { } } +fn report_trait_method_mismatch<'tcx>( + infcx: &InferCtxt<'tcx>, + mut cause: ObligationCause<'tcx>, + terr: TypeError<'tcx>, + (trait_m, trait_fty): (&ty::AssocItem, Ty<'tcx>), + (impl_m, impl_fty): (&ty::AssocItem, Ty<'tcx>), + trait_sig: ty::FnSig<'tcx>, + impl_trait_ref: ty::TraitRef<'tcx>, +) -> ErrorGuaranteed { + let tcx = infcx.tcx; + let (impl_err_span, trait_err_span) = + extract_spans_for_error_reporting(&infcx, terr, &cause, impl_m, trait_m); + + let mut diag = struct_span_err!( + tcx.sess, + impl_err_span, + E0053, + "method `{}` has an incompatible type for trait", + trait_m.name + ); + match &terr { + TypeError::ArgumentMutability(0) | TypeError::ArgumentSorts(_, 0) + if trait_m.fn_has_self_parameter => + { + let ty = trait_sig.inputs()[0]; + let sugg = match ExplicitSelf::determine(ty, |_| ty == impl_trait_ref.self_ty()) { + ExplicitSelf::ByValue => "self".to_owned(), + ExplicitSelf::ByReference(_, hir::Mutability::Not) => "&self".to_owned(), + ExplicitSelf::ByReference(_, hir::Mutability::Mut) => "&mut self".to_owned(), + _ => format!("self: {ty}"), + }; + + // When the `impl` receiver is an arbitrary self type, like `self: Box<Self>`, the + // span points only at the type `Box<Self`>, but we want to cover the whole + // argument pattern and type. + let span = match tcx.hir().expect_impl_item(impl_m.def_id.expect_local()).kind { + ImplItemKind::Fn(ref sig, body) => tcx + .hir() + .body_param_names(body) + .zip(sig.decl.inputs.iter()) + .map(|(param, ty)| param.span.to(ty.span)) + .next() + .unwrap_or(impl_err_span), + _ => bug!("{:?} is not a method", impl_m), + }; + + diag.span_suggestion( + span, + "change the self-receiver type to match the trait", + sugg, + Applicability::MachineApplicable, + ); + } + TypeError::ArgumentMutability(i) | TypeError::ArgumentSorts(_, i) => { + if trait_sig.inputs().len() == *i { + // Suggestion to change output type. We do not suggest in `async` functions + // to avoid complex logic or incorrect output. + match tcx.hir().expect_impl_item(impl_m.def_id.expect_local()).kind { + ImplItemKind::Fn(ref sig, _) if !sig.header.asyncness.is_async() => { + let msg = "change the output type to match the trait"; + let ap = Applicability::MachineApplicable; + match sig.decl.output { + hir::FnRetTy::DefaultReturn(sp) => { + let sugg = format!("-> {} ", trait_sig.output()); + diag.span_suggestion_verbose(sp, msg, sugg, ap); + } + hir::FnRetTy::Return(hir_ty) => { + let sugg = trait_sig.output(); + diag.span_suggestion(hir_ty.span, msg, sugg, ap); + } + }; + } + _ => {} + }; + } else if let Some(trait_ty) = trait_sig.inputs().get(*i) { + diag.span_suggestion( + impl_err_span, + "change the parameter type to match the trait", + trait_ty, + Applicability::MachineApplicable, + ); + } + } + _ => {} + } + + cause.span = impl_err_span; + infcx.err_ctxt().note_type_err( + &mut diag, + &cause, + trait_err_span.map(|sp| (sp, "type in trait".to_owned())), + Some(infer::ValuePairs::Terms(ExpectedFound { + expected: trait_fty.into(), + found: impl_fty.into(), + })), + terr, + false, + false, + ); + + return diag.emit(); +} + fn check_region_bounds_on_impl_item<'tcx>( tcx: TyCtxt<'tcx>, impl_m: &ty::AssocItem, trait_m: &ty::AssocItem, - trait_generics: &ty::Generics, - impl_generics: &ty::Generics, + delay: bool, ) -> Result<(), ErrorGuaranteed> { - let trait_params = trait_generics.own_counts().lifetimes; + let impl_generics = tcx.generics_of(impl_m.def_id); let impl_params = impl_generics.own_counts().lifetimes; + let trait_generics = tcx.generics_of(trait_m.def_id); + let trait_params = trait_generics.own_counts().lifetimes; + debug!( "check_region_bounds_on_impl_item: \ trait_generics={:?} \ @@ -729,23 +837,56 @@ fn check_region_bounds_on_impl_item<'tcx>( .get_generics(impl_m.def_id.expect_local()) .expect("expected impl item to have generics or else we can't compare them") .span; - let generics_span = if let Some(local_def_id) = trait_m.def_id.as_local() { - Some( - tcx.hir() - .get_generics(local_def_id) - .expect("expected trait item to have generics or else we can't compare them") - .span, - ) - } else { - None - }; - let reported = tcx.sess.emit_err(LifetimesOrBoundsMismatchOnTrait { - span, - item_kind: assoc_item_kind_str(impl_m), - ident: impl_m.ident(tcx), - generics_span, - }); + let mut generics_span = None; + let mut bounds_span = vec![]; + let mut where_span = None; + if let Some(trait_node) = tcx.hir().get_if_local(trait_m.def_id) + && let Some(trait_generics) = trait_node.generics() + { + generics_span = Some(trait_generics.span); + // FIXME: we could potentially look at the impl's bounds to not point at bounds that + // *are* present in the impl. + for p in trait_generics.predicates { + if let hir::WherePredicate::BoundPredicate(pred) = p { + for b in pred.bounds { + if let hir::GenericBound::Outlives(lt) = b { + bounds_span.push(lt.ident.span); + } + } + } + } + if let Some(impl_node) = tcx.hir().get_if_local(impl_m.def_id) + && let Some(impl_generics) = impl_node.generics() + { + let mut impl_bounds = 0; + for p in impl_generics.predicates { + if let hir::WherePredicate::BoundPredicate(pred) = p { + for b in pred.bounds { + if let hir::GenericBound::Outlives(_) = b { + impl_bounds += 1; + } + } + } + } + if impl_bounds == bounds_span.len() { + bounds_span = vec![]; + } else if impl_generics.has_where_clause_predicates { + where_span = Some(impl_generics.where_clause_span); + } + } + } + let reported = tcx + .sess + .create_err(LifetimesOrBoundsMismatchOnTrait { + span, + item_kind: assoc_item_kind_str(impl_m), + ident: impl_m.ident(tcx), + generics_span, + bounds_span, + where_span, + }) + .emit_unless(delay); return Err(reported); } @@ -891,9 +1032,9 @@ fn compare_self_type<'tcx>( fn compare_number_of_generics<'tcx>( tcx: TyCtxt<'tcx>, impl_: &ty::AssocItem, - _impl_span: Span, trait_: &ty::AssocItem, trait_span: Option<Span>, + delay: bool, ) -> Result<(), ErrorGuaranteed> { let trait_own_counts = tcx.generics_of(trait_.def_id).own_counts(); let impl_own_counts = tcx.generics_of(impl_.def_id).own_counts(); @@ -1023,7 +1164,7 @@ fn compare_number_of_generics<'tcx>( err.span_label(*span, "`impl Trait` introduces an implicit type parameter"); } - let reported = err.emit(); + let reported = err.emit_unless(delay); err_occurred = Some(reported); } } @@ -1275,6 +1416,7 @@ fn compare_generic_param_kinds<'tcx>( tcx: TyCtxt<'tcx>, impl_item: &ty::AssocItem, trait_item: &ty::AssocItem, + delay: bool, ) -> Result<(), ErrorGuaranteed> { assert_eq!(impl_item.kind, trait_item.kind); @@ -1332,7 +1474,7 @@ fn compare_generic_param_kinds<'tcx>( err.span_label(impl_header_span, ""); err.span_label(param_impl_span, make_param_message("found", param_impl)); - let reported = err.emit(); + let reported = err.emit_unless(delay); return Err(reported); } } @@ -1381,18 +1523,15 @@ pub(crate) fn raw_compare_const_impl<'tcx>( ); // There is no "body" here, so just pass dummy id. - let impl_ty = ocx.normalize(cause.clone(), param_env, impl_ty); + let impl_ty = ocx.normalize(&cause, param_env, impl_ty); debug!("compare_const_impl: impl_ty={:?}", impl_ty); - let trait_ty = ocx.normalize(cause.clone(), param_env, trait_ty); + let trait_ty = ocx.normalize(&cause, param_env, trait_ty); debug!("compare_const_impl: trait_ty={:?}", trait_ty); - let err = infcx - .at(&cause, param_env) - .sup(trait_ty, impl_ty) - .map(|ok| ocx.register_infer_ok_obligations(ok)); + let err = ocx.sup(&cause, param_env, trait_ty, impl_ty); if let Err(terr) = err { debug!( @@ -1441,7 +1580,7 @@ pub(crate) fn raw_compare_const_impl<'tcx>( // version. let errors = ocx.select_all_or_error(); if !errors.is_empty() { - return Err(infcx.err_ctxt().report_fulfillment_errors(&errors, None, false)); + return Err(infcx.err_ctxt().report_fulfillment_errors(&errors, None)); } // FIXME return `ErrorReported` if region obligations error? @@ -1461,9 +1600,9 @@ pub(crate) fn compare_ty_impl<'tcx>( debug!("compare_impl_type(impl_trait_ref={:?})", impl_trait_ref); let _: Result<(), ErrorGuaranteed> = (|| { - compare_number_of_generics(tcx, impl_ty, impl_ty_span, trait_ty, trait_item_span)?; + compare_number_of_generics(tcx, impl_ty, trait_ty, trait_item_span, false)?; - compare_generic_param_kinds(tcx, impl_ty, trait_ty)?; + compare_generic_param_kinds(tcx, impl_ty, trait_ty, false)?; let sp = tcx.def_span(impl_ty.def_id); compare_type_predicate_entailment(tcx, impl_ty, sp, trait_ty, impl_trait_ref)?; @@ -1485,18 +1624,10 @@ fn compare_type_predicate_entailment<'tcx>( let trait_to_impl_substs = impl_substs.rebase_onto(tcx, impl_ty.container_id(tcx), impl_trait_ref.substs); - let impl_ty_generics = tcx.generics_of(impl_ty.def_id); - let trait_ty_generics = tcx.generics_of(trait_ty.def_id); let impl_ty_predicates = tcx.predicates_of(impl_ty.def_id); let trait_ty_predicates = tcx.predicates_of(trait_ty.def_id); - check_region_bounds_on_impl_item( - tcx, - impl_ty, - trait_ty, - &trait_ty_generics, - &impl_ty_generics, - )?; + check_region_bounds_on_impl_item(tcx, impl_ty, trait_ty, false)?; let impl_ty_own_bounds = impl_ty_predicates.instantiate_own(tcx, impl_substs); @@ -1533,14 +1664,11 @@ fn compare_type_predicate_entailment<'tcx>( debug!("compare_type_predicate_entailment: caller_bounds={:?}", param_env.caller_bounds()); - let mut selcx = traits::SelectionContext::new(&infcx); - assert_eq!(impl_ty_own_bounds.predicates.len(), impl_ty_own_bounds.spans.len()); for (span, predicate) in std::iter::zip(impl_ty_own_bounds.spans, impl_ty_own_bounds.predicates) { let cause = ObligationCause::misc(span, impl_ty_hir_id); - let traits::Normalized { value: predicate, obligations } = - traits::normalize(&mut selcx, param_env, cause, predicate); + let predicate = ocx.normalize(&cause, param_env, predicate); let cause = ObligationCause::new( span, @@ -1551,15 +1679,14 @@ fn compare_type_predicate_entailment<'tcx>( kind: impl_ty.kind, }, ); - ocx.register_obligations(obligations); - ocx.register_obligation(traits::Obligation::new(cause, param_env, predicate)); + ocx.register_obligation(traits::Obligation::new(tcx, cause, param_env, predicate)); } // Check that all obligations are satisfied by the implementation's // version. let errors = ocx.select_all_or_error(); if !errors.is_empty() { - let reported = infcx.err_ctxt().report_fulfillment_errors(&errors, None, false); + let reported = infcx.err_ctxt().report_fulfillment_errors(&errors, None); return Err(reported); } @@ -1665,13 +1792,10 @@ pub fn check_type_bounds<'tcx>( GenericParamDefKind::Const { .. } => { let bound_var = ty::BoundVariableKind::Const; bound_vars.push(bound_var); - tcx.mk_const(ty::ConstS { - ty: tcx.type_of(param.def_id), - kind: ty::ConstKind::Bound( - ty::INNERMOST, - ty::BoundVar::from_usize(bound_vars.len() - 1), - ), - }) + tcx.mk_const( + ty::ConstKind::Bound(ty::INNERMOST, ty::BoundVar::from_usize(bound_vars.len() - 1)), + tcx.type_of(param.def_id), + ) .into() } }); @@ -1737,7 +1861,6 @@ pub fn check_type_bounds<'tcx>( let assumed_wf_types = ocx.assumed_wf_types(param_env, impl_ty_span, impl_ty.def_id.expect_local()); - let mut selcx = traits::SelectionContext::new(&infcx); let normalize_cause = ObligationCause::new( impl_ty_span, impl_ty_hir_id, @@ -1760,29 +1883,24 @@ pub fn check_type_bounds<'tcx>( .subst_iter_copied(tcx, rebased_substs) .map(|(concrete_ty_bound, span)| { debug!("check_type_bounds: concrete_ty_bound = {:?}", concrete_ty_bound); - traits::Obligation::new(mk_cause(span), param_env, concrete_ty_bound) + traits::Obligation::new(tcx, mk_cause(span), param_env, concrete_ty_bound) }) .collect(); debug!("check_type_bounds: item_bounds={:?}", obligations); for mut obligation in util::elaborate_obligations(tcx, obligations) { - let traits::Normalized { value: normalized_predicate, obligations } = traits::normalize( - &mut selcx, - normalize_param_env, - normalize_cause.clone(), - obligation.predicate, - ); + let normalized_predicate = + ocx.normalize(&normalize_cause, normalize_param_env, obligation.predicate); debug!("compare_projection_bounds: normalized predicate = {:?}", normalized_predicate); obligation.predicate = normalized_predicate; - ocx.register_obligations(obligations); ocx.register_obligation(obligation); } // Check that all obligations are satisfied by the implementation's // version. let errors = ocx.select_all_or_error(); if !errors.is_empty() { - let reported = infcx.err_ctxt().report_fulfillment_errors(&errors, None, false); + let reported = infcx.err_ctxt().report_fulfillment_errors(&errors, None); return Err(reported); } |