diff --git a/compiler/rustc_hir_analysis/src/collect/predicates_of.rs b/compiler/rustc_hir_analysis/src/collect/predicates_of.rs index d9b2aacab9d..0fa4c786e66 100644 --- a/compiler/rustc_hir_analysis/src/collect/predicates_of.rs +++ b/compiler/rustc_hir_analysis/src/collect/predicates_of.rs @@ -2,7 +2,7 @@ use crate::astconv::{AstConv, OnlySelfBounds, PredicateFilter}; use crate::bounds::Bounds; use crate::collect::ItemCtxt; use crate::constrained_generic_params as cgp; -use hir::{HirId, Node}; +use hir::{HirId, Lifetime, Node}; use rustc_data_structures::fx::FxIndexSet; use rustc_hir as hir; use rustc_hir::def::DefKind; @@ -10,9 +10,9 @@ use rustc_hir::def_id::{DefId, LocalDefId}; use rustc_hir::intravisit::{self, Visitor}; use rustc_middle::ty::subst::InternalSubsts; use rustc_middle::ty::{self, Ty, TyCtxt}; -use rustc_middle::ty::{GenericPredicates, ToPredicate}; +use rustc_middle::ty::{GenericPredicates, Generics, ToPredicate}; use rustc_span::symbol::{sym, Ident}; -use rustc_span::{Span, DUMMY_SP}; +use rustc_span::{Span, Symbol, DUMMY_SP}; /// Returns a list of all type predicates (explicit and implicit) for the definition with /// ID `def_id`. This includes all predicates returned by `predicates_defined_on`, plus @@ -289,38 +289,16 @@ fn gather_explicit_predicates_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Gen bug!("unexpected {opaque_ty_node:?}") }; debug!(?lifetimes); - for (arg, duplicate) in std::iter::zip(lifetimes, ast_generics.params) { - let hir::GenericArg::Lifetime(arg) = arg else { bug!() }; - let orig_region = icx.astconv().ast_region_to_region(&arg, None); - if !matches!(orig_region.kind(), ty::ReEarlyBound(..)) { - // Only early-bound regions can point to the original generic parameter. - continue; - } - let hir::GenericParamKind::Lifetime { .. } = duplicate.kind else { continue }; - let dup_def = duplicate.def_id.to_def_id(); + let lifetime_mapping = std::iter::zip(lifetimes, ast_generics.params) + .map(|(arg, dup)| { + let hir::GenericArg::Lifetime(arg) = arg else { bug!() }; + (**arg, dup) + }) + .filter(|(_, dup)| matches!(dup.kind, hir::GenericParamKind::Lifetime { .. })) + .map(|(lifetime, dup)| (lifetime, (dup.def_id, dup.name.ident().name, dup.span))); - let Some(dup_index) = generics.param_def_id_to_index(tcx, dup_def) else { bug!() }; - - let dup_region = ty::Region::new_early_bound( - tcx, - ty::EarlyBoundRegion { - def_id: dup_def, - index: dup_index, - name: duplicate.name.ident().name, - }, - ); - predicates.push(( - ty::ClauseKind::RegionOutlives(ty::OutlivesPredicate(orig_region, dup_region)) - .to_predicate(icx.tcx), - duplicate.span, - )); - predicates.push(( - ty::ClauseKind::RegionOutlives(ty::OutlivesPredicate(dup_region, orig_region)) - .to_predicate(icx.tcx), - duplicate.span, - )); - } + bidirectional_lifetime_predicates(tcx, def_id, lifetime_mapping, generics, &mut predicates); debug!(?predicates); } @@ -330,6 +308,46 @@ fn gather_explicit_predicates_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Gen } } +/// Opaques have duplicated lifetimes and we need to compute bidirectional outlives predicates to +/// enforce that these lifetimes stay in sync. +fn compute_bidirectional_outlives_predicates<'tcx>( + tcx: TyCtxt<'tcx>, + item_def_id: LocalDefId, + lifetime_mapping: impl Iterator, + generics: &Generics, + predicates: &mut Vec<(ty::Clause<'tcx>, Span)>, +) { + let icx = ItemCtxt::new(tcx, item_def_id); + + for (arg, (dup_def, name, span)) in lifetime_mapping { + let orig_region = icx.astconv().ast_region_to_region(&arg, None); + if !matches!(orig_region.kind(), ty::ReEarlyBound(..)) { + // There is no late-bound lifetime to actually match up here, since the lifetime doesn't + // show up in the opaque's parent's substs. + continue; + } + + let Some(dup_index) = generics.param_def_id_to_index(icx.tcx, dup_def.to_def_id()) else { bug!() }; + + let dup_region = ty::Region::new_early_bound( + tcx, + ty::EarlyBoundRegion { def_id: dup_def.to_def_id(), index: dup_index, name }, + ); + + predicates.push(( + ty::ClauseKind::RegionOutlives(ty::OutlivesPredicate(orig_region, dup_region)) + .to_predicate(tcx), + span, + )); + + predicates.push(( + ty::ClauseKind::RegionOutlives(ty::OutlivesPredicate(dup_region, orig_region)) + .to_predicate(tcx), + span, + )); + } +} + fn const_evaluatable_predicates_of( tcx: TyCtxt<'_>, def_id: LocalDefId,