diff options
Diffstat (limited to 'compiler/rustc_borrowck/src/type_check/free_region_relations.rs')
| -rw-r--r-- | compiler/rustc_borrowck/src/type_check/free_region_relations.rs | 64 |
1 files changed, 29 insertions, 35 deletions
diff --git a/compiler/rustc_borrowck/src/type_check/free_region_relations.rs b/compiler/rustc_borrowck/src/type_check/free_region_relations.rs index cc0318ede..f1b1c33a1 100644 --- a/compiler/rustc_borrowck/src/type_check/free_region_relations.rs +++ b/compiler/rustc_borrowck/src/type_check/free_region_relations.rs @@ -1,5 +1,5 @@ use rustc_data_structures::frozen::Frozen; -use rustc_data_structures::transitive_relation::TransitiveRelation; +use rustc_data_structures::transitive_relation::{TransitiveRelation, TransitiveRelationBuilder}; use rustc_infer::infer::canonical::QueryRegionConstraints; use rustc_infer::infer::outlives; use rustc_infer::infer::outlives::env::RegionBoundPairs; @@ -61,25 +61,13 @@ pub(crate) fn create<'tcx>( constraints, universal_regions: universal_regions.clone(), region_bound_pairs: Default::default(), - relations: UniversalRegionRelations { - universal_regions: universal_regions.clone(), - outlives: Default::default(), - inverse_outlives: Default::default(), - }, + outlives: Default::default(), + inverse_outlives: Default::default(), } .create() } impl UniversalRegionRelations<'_> { - /// Records in the `outlives_relation` (and - /// `inverse_outlives_relation`) that `fr_a: fr_b`. Invoked by the - /// builder below. - fn relate_universal_regions(&mut self, fr_a: RegionVid, fr_b: RegionVid) { - debug!("relate_universal_regions: fr_a={:?} outlives fr_b={:?}", fr_a, fr_b); - self.outlives.add(fr_a, fr_b); - self.inverse_outlives.add(fr_b, fr_a); - } - /// Given two universal regions, returns the postdominating /// upper-bound (effectively the least upper bound). /// @@ -216,11 +204,20 @@ struct UniversalRegionRelationsBuilder<'this, 'tcx> { constraints: &'this mut MirTypeckRegionConstraints<'tcx>, // outputs: - relations: UniversalRegionRelations<'tcx>, + outlives: TransitiveRelationBuilder<RegionVid>, + inverse_outlives: TransitiveRelationBuilder<RegionVid>, region_bound_pairs: RegionBoundPairs<'tcx>, } impl<'tcx> UniversalRegionRelationsBuilder<'_, 'tcx> { + /// Records in the `outlives_relation` (and + /// `inverse_outlives_relation`) that `fr_a: fr_b`. + fn relate_universal_regions(&mut self, fr_a: RegionVid, fr_b: RegionVid) { + debug!("relate_universal_regions: fr_a={:?} outlives fr_b={:?}", fr_a, fr_b); + self.outlives.add(fr_a, fr_b); + self.inverse_outlives.add(fr_b, fr_a); + } + pub(crate) fn create(mut self) -> CreateResult<'tcx> { let unnormalized_input_output_tys = self .universal_regions @@ -242,10 +239,9 @@ impl<'tcx> UniversalRegionRelationsBuilder<'_, 'tcx> { let constraint_sets: Vec<_> = unnormalized_input_output_tys .flat_map(|ty| { debug!("build: input_or_output={:?}", ty); - // We only add implied bounds for the normalized type as the unnormalized - // type may not actually get checked by the caller. - // - // Can otherwise be unsound, see #91068. + // We add implied bounds from both the unnormalized and normalized ty. + // See issue #87748 + let constraints_implied1 = self.add_implied_bounds(ty); let TypeOpOutput { output: norm_ty, constraints: constraints1, .. } = self .param_env .and(type_op::normalize::Normalize::new(ty)) @@ -269,13 +265,14 @@ impl<'tcx> UniversalRegionRelationsBuilder<'_, 'tcx> { // } // impl Foo for () { // type Bar = (); - // fn foo(&self) ->&() {} + // fn foo(&self) -> &() {} // } // ``` // Both &Self::Bar and &() are WF - let constraints_implied = self.add_implied_bounds(norm_ty); + let constraints_implied2 = + if ty != norm_ty { self.add_implied_bounds(norm_ty) } else { None }; normalized_inputs_and_output.push(norm_ty); - constraints1.into_iter().chain(constraints_implied) + constraints1.into_iter().chain(constraints_implied1).chain(constraints_implied2) }) .collect(); @@ -292,9 +289,9 @@ impl<'tcx> UniversalRegionRelationsBuilder<'_, 'tcx> { let fr_fn_body = self.universal_regions.fr_fn_body; for fr in self.universal_regions.universal_regions() { debug!("build: relating free region {:?} to itself and to 'static", fr); - self.relations.relate_universal_regions(fr, fr); - self.relations.relate_universal_regions(fr_static, fr); - self.relations.relate_universal_regions(fr, fr_fn_body); + self.relate_universal_regions(fr, fr); + self.relate_universal_regions(fr_static, fr); + self.relate_universal_regions(fr, fr_fn_body); } for data in &constraint_sets { @@ -313,7 +310,11 @@ impl<'tcx> UniversalRegionRelationsBuilder<'_, 'tcx> { } CreateResult { - universal_region_relations: Frozen::freeze(self.relations), + universal_region_relations: Frozen::freeze(UniversalRegionRelations { + universal_regions: self.universal_regions, + outlives: self.outlives.freeze(), + inverse_outlives: self.inverse_outlives.freeze(), + }), region_bound_pairs: self.region_bound_pairs, normalized_inputs_and_output, } @@ -346,17 +347,10 @@ impl<'tcx> UniversalRegionRelationsBuilder<'_, 'tcx> { match outlives_bound { OutlivesBound::RegionSubRegion(r1, r2) => { - // `where Type:` is lowered to `where Type: 'empty` so that - // we check `Type` is well formed, but there's no use for - // this bound here. - if r1.is_empty() { - return; - } - // The bound says that `r1 <= r2`; we store `r2: r1`. let r1 = self.universal_regions.to_region_vid(r1); let r2 = self.universal_regions.to_region_vid(r2); - self.relations.relate_universal_regions(r2, r1); + self.relate_universal_regions(r2, r1); } OutlivesBound::RegionSubParam(r_a, param_b) => { |