diff options
Diffstat (limited to '')
-rw-r--r-- | compiler/rustc_typeck/src/check/wfcheck.rs | 196 |
1 files changed, 106 insertions, 90 deletions
diff --git a/compiler/rustc_typeck/src/check/wfcheck.rs b/compiler/rustc_typeck/src/check/wfcheck.rs index d0334cd0d..27b3da8ab 100644 --- a/compiler/rustc_typeck/src/check/wfcheck.rs +++ b/compiler/rustc_typeck/src/check/wfcheck.rs @@ -1,5 +1,5 @@ -use crate::check::regionck::OutlivesEnvironmentExt; use crate::constrained_generic_params::{identify_constrained_generic_params, Parameter}; +use hir::def::DefKind; use rustc_ast as ast; use rustc_data_structures::fx::{FxHashMap, FxHashSet}; use rustc_errors::{pluralize, struct_span_err, Applicability, DiagnosticBuilder, ErrorGuaranteed}; @@ -10,7 +10,7 @@ use rustc_hir::ItemKind; use rustc_infer::infer::outlives::env::{OutlivesEnvironment, RegionBoundPairs}; use rustc_infer::infer::outlives::obligations::TypeOutlives; use rustc_infer::infer::{self, InferCtxt, TyCtxtInferExt}; -use rustc_infer::traits::Normalized; +use rustc_middle::mir::ConstraintCategory; use rustc_middle::ty::query::Providers; use rustc_middle::ty::subst::{GenericArgKind, InternalSubsts, Subst}; use rustc_middle::ty::trait_def::TraitSpecializationKind; @@ -23,9 +23,8 @@ use rustc_span::symbol::{sym, Ident, Symbol}; use rustc_span::{Span, DUMMY_SP}; use rustc_trait_selection::autoderef::Autoderef; use rustc_trait_selection::traits::error_reporting::InferCtxtExt; +use rustc_trait_selection::traits::outlives_bounds::InferCtxtExt as _; use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt as _; -use rustc_trait_selection::traits::query::normalize::AtExt; -use rustc_trait_selection::traits::query::NoSolution; use rustc_trait_selection::traits::{ self, ObligationCause, ObligationCauseCode, ObligationCtxt, WellFormedLoc, }; @@ -72,9 +71,11 @@ impl<'tcx> WfCheckingCtxt<'_, 'tcx> { ) { let cause = traits::ObligationCause::new(span, self.body_id, ObligationCauseCode::WellFormed(loc)); + // for a type to be WF, we do not need to check if const trait predicates satisfy. + let param_env = self.param_env.without_const(); self.ocx.register_obligation(traits::Obligation::new( cause, - self.param_env, + param_env, ty::Binder::dummy(ty::PredicateKind::WellFormed(arg)).to_predicate(self.tcx()), )); } @@ -86,26 +87,31 @@ pub(super) fn enter_wf_checking_ctxt<'tcx, F>( body_def_id: LocalDefId, f: F, ) where - F: for<'a> FnOnce(&WfCheckingCtxt<'a, 'tcx>) -> FxHashSet<Ty<'tcx>>, + F: for<'a> FnOnce(&WfCheckingCtxt<'a, 'tcx>), { let param_env = tcx.param_env(body_def_id); let body_id = tcx.hir().local_def_id_to_hir_id(body_def_id); tcx.infer_ctxt().enter(|ref infcx| { let ocx = ObligationCtxt::new(infcx); + + let assumed_wf_types = ocx.assumed_wf_types(param_env, span, body_def_id); + let mut wfcx = WfCheckingCtxt { ocx, span, body_id, param_env }; if !tcx.features().trivial_bounds { wfcx.check_false_global_bounds() } - let wf_tys = f(&mut wfcx); + f(&mut wfcx); let errors = wfcx.select_all_or_error(); if !errors.is_empty() { infcx.report_fulfillment_errors(&errors, None, false); return; } - let mut outlives_environment = OutlivesEnvironment::new(param_env); - outlives_environment.add_implied_bounds(infcx, wf_tys, body_id); + let implied_bounds = infcx.implied_bounds_tys(param_env, body_id, assumed_wf_types); + let outlives_environment = + OutlivesEnvironment::with_bounds(param_env, Some(infcx), implied_bounds); + infcx.check_region_obligations_and_report_errors(body_def_id, &outlives_environment); }) } @@ -383,7 +389,7 @@ fn check_gat_where_clauses(tcx: TyCtxt<'_>, associated_items: &[hir::TraitItemRe tcx, param_env, item_hir_id, - sig.output(), + sig.inputs_and_output, // We also assume that all of the function signature's parameter types // are well formed. &sig.inputs().iter().copied().collect(), @@ -658,7 +664,7 @@ fn ty_known_to_outlive<'tcx>( resolve_regions_with_wf_tys(tcx, id, param_env, &wf_tys, |infcx, region_bound_pairs| { let origin = infer::RelateParamBound(DUMMY_SP, ty, None); let outlives = &mut TypeOutlives::new(infcx, tcx, region_bound_pairs, None, param_env); - outlives.type_must_outlive(origin, ty, region); + outlives.type_must_outlive(origin, ty, region, ConstraintCategory::BoringNoLocation); }) } @@ -676,7 +682,12 @@ fn region_known_to_outlive<'tcx>( use rustc_infer::infer::outlives::obligations::TypeOutlivesDelegate; let origin = infer::RelateRegionParamBound(DUMMY_SP); // `region_a: region_b` -> `region_b <= region_a` - infcx.push_sub_region_constraint(origin, region_b, region_a); + infcx.push_sub_region_constraint( + origin, + region_b, + region_a, + ConstraintCategory::BoringNoLocation, + ); }) } @@ -694,8 +705,11 @@ fn resolve_regions_with_wf_tys<'tcx>( // region constraints get added and solved there and we need to test each // call individually. tcx.infer_ctxt().enter(|infcx| { - let mut outlives_environment = OutlivesEnvironment::new(param_env); - outlives_environment.add_implied_bounds(&infcx, wf_tys.clone(), id); + let outlives_environment = OutlivesEnvironment::with_bounds( + param_env, + Some(&infcx), + infcx.implied_bounds_tys(param_env, id, wf_tys.clone()), + ); let region_bound_pairs = outlives_environment.region_bound_pairs(); add_constraints(&infcx, region_bound_pairs); @@ -761,7 +775,7 @@ impl<'tcx> TypeVisitor<'tcx> for GATSubstCollector<'tcx> { fn could_be_self(trait_def_id: LocalDefId, ty: &hir::Ty<'_>) -> bool { match ty.kind { hir::TyKind::TraitObject([trait_ref], ..) => match trait_ref.trait_ref.path.segments { - [s] => s.res.and_then(|r| r.opt_def_id()) == Some(trait_def_id.to_def_id()), + [s] => s.res.opt_def_id() == Some(trait_def_id.to_def_id()), _ => false, }, _ => false, @@ -965,7 +979,7 @@ fn check_param_wf(tcx: TyCtxt<'_>, param: &hir::GenericParam<'_>) { } } -#[tracing::instrument(level = "debug", skip(tcx, span, sig_if_method))] +#[instrument(level = "debug", skip(tcx, span, sig_if_method))] fn check_associated_item( tcx: TyCtxt<'_>, item_id: LocalDefId, @@ -976,15 +990,9 @@ fn check_associated_item( enter_wf_checking_ctxt(tcx, span, item_id, |wfcx| { let item = tcx.associated_item(item_id); - let (mut implied_bounds, self_ty) = match item.container { - ty::TraitContainer => (FxHashSet::default(), tcx.types.self_param), - ty::ImplContainer => { - let def_id = item.container_id(tcx); - ( - impl_implied_bounds(tcx, wfcx.param_env, def_id.expect_local(), span), - tcx.type_of(def_id), - ) - } + let self_ty = match item.container { + ty::TraitContainer => tcx.types.self_param, + ty::ImplContainer => tcx.type_of(item.container_id(tcx)), }; match item.kind { @@ -1002,7 +1010,6 @@ fn check_associated_item( sig, hir_sig.decl, item.def_id.expect_local(), - &mut implied_bounds, ); check_method_receiver(wfcx, hir_sig, item, self_ty); } @@ -1017,8 +1024,6 @@ fn check_associated_item( } } } - - implied_bounds }) } @@ -1118,9 +1123,6 @@ fn check_type_defn<'tcx, F>( } check_where_clauses(wfcx, item.span, item.def_id); - - // No implied bounds in a struct definition. - FxHashSet::default() }); } @@ -1144,9 +1146,7 @@ fn check_trait(tcx: TyCtxt<'_>, item: &hir::Item<'_>) { } enter_wf_checking_ctxt(tcx, item.span, item.def_id, |wfcx| { - check_where_clauses(wfcx, item.span, item.def_id); - - FxHashSet::default() + check_where_clauses(wfcx, item.span, item.def_id) }); // Only check traits, don't check trait aliases @@ -1186,9 +1186,7 @@ fn check_item_fn( ) { enter_wf_checking_ctxt(tcx, span, def_id, |wfcx| { let sig = tcx.fn_sig(def_id); - let mut implied_bounds = FxHashSet::default(); - check_fn_or_method(wfcx, ident.span, sig, decl, def_id, &mut implied_bounds); - implied_bounds + check_fn_or_method(wfcx, ident.span, sig, decl, def_id); }) } @@ -1231,13 +1229,10 @@ fn check_item_type(tcx: TyCtxt<'_>, item_id: LocalDefId, ty_span: Span, allow_fo tcx.require_lang_item(LangItem::Sync, Some(ty_span)), ); } - - // No implied bounds in a const, etc. - FxHashSet::default() }); } -#[tracing::instrument(level = "debug", skip(tcx, ast_self_ty, ast_trait_ref))] +#[instrument(level = "debug", skip(tcx, ast_self_ty, ast_trait_ref))] fn check_impl<'tcx>( tcx: TyCtxt<'tcx>, item: &'tcx hir::Item<'tcx>, @@ -1274,7 +1269,11 @@ fn check_impl<'tcx>( } None => { let self_ty = tcx.type_of(item.def_id); - let self_ty = wfcx.normalize(item.span, None, self_ty); + let self_ty = wfcx.normalize( + item.span, + Some(WellFormedLoc::Ty(item.hir_id().expect_owner())), + self_ty, + ); wfcx.register_wf_obligation( ast_self_ty.span, Some(WellFormedLoc::Ty(item.hir_id().expect_owner())), @@ -1284,8 +1283,6 @@ fn check_impl<'tcx>( } check_where_clauses(wfcx, item.span, item.def_id); - - impl_implied_bounds(tcx, wfcx.param_env, item.def_id, item.span) }); } @@ -1321,7 +1318,11 @@ fn check_where_clauses<'tcx>(wfcx: &WfCheckingCtxt<'_, 'tcx>, span: Span, def_id // parameter includes another (e.g., `<T, U = T>`). In those cases, we can't // be sure if it will error or not as user might always specify the other. if !ty.needs_subst() { - wfcx.register_wf_obligation(tcx.def_span(param.def_id), None, ty.into()); + wfcx.register_wf_obligation( + tcx.def_span(param.def_id), + Some(WellFormedLoc::Ty(param.def_id.expect_local())), + ty.into(), + ); } } } @@ -1465,21 +1466,26 @@ fn check_where_clauses<'tcx>(wfcx: &WfCheckingCtxt<'_, 'tcx>, span: Span, def_id assert_eq!(predicates.predicates.len(), predicates.spans.len()); let wf_obligations = iter::zip(&predicates.predicates, &predicates.spans).flat_map(|(&p, &sp)| { - traits::wf::predicate_obligations(infcx, wfcx.param_env, wfcx.body_id, p, sp) + traits::wf::predicate_obligations( + infcx, + wfcx.param_env.without_const(), + wfcx.body_id, + p, + sp, + ) }); let obligations: Vec<_> = wf_obligations.chain(default_obligations).collect(); wfcx.register_obligations(obligations); } -#[tracing::instrument(level = "debug", skip(wfcx, span, hir_decl))] +#[instrument(level = "debug", skip(wfcx, span, hir_decl))] fn check_fn_or_method<'tcx>( wfcx: &WfCheckingCtxt<'_, 'tcx>, span: Span, sig: ty::PolyFnSig<'tcx>, hir_decl: &hir::FnDecl<'_>, def_id: LocalDefId, - implied_bounds: &mut FxHashSet<Ty<'tcx>>, ) { let tcx = wfcx.tcx(); let sig = tcx.liberate_late_bound_regions(def_id.to_def_id(), sig); @@ -1521,23 +1527,66 @@ fn check_fn_or_method<'tcx>( ); } - implied_bounds.extend(sig.inputs()); - - wfcx.register_wf_obligation(hir_decl.output.span(), None, sig.output().into()); + wfcx.register_wf_obligation( + hir_decl.output.span(), + Some(WellFormedLoc::Param { + function: def_id, + param_idx: sig.inputs().len().try_into().unwrap(), + }), + sig.output().into(), + ); - // FIXME(#27579) return types should not be implied bounds - implied_bounds.insert(sig.output()); + check_where_clauses(wfcx, span, def_id); - debug!(?implied_bounds); + check_return_position_impl_trait_in_trait_bounds( + tcx, + wfcx, + def_id, + sig.output(), + hir_decl.output.span(), + ); +} - check_where_clauses(wfcx, span, def_id); +/// Basically `check_associated_type_bounds`, but separated for now and should be +/// deduplicated when RPITITs get lowered into real associated items. +fn check_return_position_impl_trait_in_trait_bounds<'tcx>( + tcx: TyCtxt<'tcx>, + wfcx: &WfCheckingCtxt<'_, 'tcx>, + fn_def_id: LocalDefId, + fn_output: Ty<'tcx>, + span: Span, +) { + if let Some(assoc_item) = tcx.opt_associated_item(fn_def_id.to_def_id()) + && assoc_item.container == ty::AssocItemContainer::TraitContainer + { + for arg in fn_output.walk() { + if let ty::GenericArgKind::Type(ty) = arg.unpack() + && let ty::Projection(proj) = ty.kind() + && tcx.def_kind(proj.item_def_id) == DefKind::ImplTraitPlaceholder + && tcx.impl_trait_in_trait_parent(proj.item_def_id) == fn_def_id.to_def_id() + { + let bounds = wfcx.tcx().explicit_item_bounds(proj.item_def_id); + let wf_obligations = bounds.iter().flat_map(|&(bound, bound_span)| { + let normalized_bound = wfcx.normalize(span, None, bound); + traits::wf::predicate_obligations( + wfcx.infcx, + wfcx.param_env, + wfcx.body_id, + normalized_bound, + bound_span, + ) + }); + wfcx.register_obligations(wf_obligations); + } + } + } } const HELP_FOR_SELF_TYPE: &str = "consider changing to `self`, `&self`, `&mut self`, `self: Box<Self>`, \ `self: Rc<Self>`, `self: Arc<Self>`, or `self: Pin<P>` (where P is one \ of the previous types except `Self`)"; -#[tracing::instrument(level = "debug", skip(wfcx))] +#[instrument(level = "debug", skip(wfcx))] fn check_method_receiver<'tcx>( wfcx: &WfCheckingCtxt<'_, 'tcx>, fn_sig: &hir::FnSig<'_>, @@ -1817,6 +1866,7 @@ fn report_bivariance( impl<'tcx> WfCheckingCtxt<'_, 'tcx> { /// Feature gates RFC 2056 -- trivial bounds, checking for global bounds that /// aren't true. + #[instrument(level = "debug", skip(self))] fn check_false_global_bounds(&mut self) { let tcx = self.ocx.infcx.tcx; let mut span = self.span; @@ -1924,40 +1974,6 @@ impl<'a, 'tcx> WfCheckingCtxt<'a, 'tcx> { } } -pub fn impl_implied_bounds<'tcx>( - tcx: TyCtxt<'tcx>, - param_env: ty::ParamEnv<'tcx>, - impl_def_id: LocalDefId, - span: Span, -) -> FxHashSet<Ty<'tcx>> { - // We completely ignore any obligations caused by normalizing the types - // we assume to be well formed. Considering that the user of the implied - // bounds will also normalize them, we leave it to them to emit errors - // which should result in better causes and spans. - tcx.infer_ctxt().enter(|infcx| { - let cause = ObligationCause::misc(span, tcx.hir().local_def_id_to_hir_id(impl_def_id)); - match tcx.impl_trait_ref(impl_def_id) { - Some(trait_ref) => { - // Trait impl: take implied bounds from all types that - // appear in the trait reference. - match infcx.at(&cause, param_env).normalize(trait_ref) { - Ok(Normalized { value, obligations: _ }) => value.substs.types().collect(), - Err(NoSolution) => FxHashSet::default(), - } - } - - None => { - // Inherent impl: take implied bounds from the `self` type. - let self_ty = tcx.type_of(impl_def_id); - match infcx.at(&cause, param_env).normalize(self_ty) { - Ok(Normalized { value, obligations: _ }) => FxHashSet::from_iter([value]), - Err(NoSolution) => FxHashSet::default(), - } - } - } - }) -} - fn error_392( tcx: TyCtxt<'_>, span: Span, |