diff options
Diffstat (limited to 'compiler/rustc_infer/src/infer/region_constraints/mod.rs')
| -rw-r--r-- | compiler/rustc_infer/src/infer/region_constraints/mod.rs | 107 |
1 files changed, 69 insertions, 38 deletions
diff --git a/compiler/rustc_infer/src/infer/region_constraints/mod.rs b/compiler/rustc_infer/src/infer/region_constraints/mod.rs index 71adf526097..ee97dd36807 100644 --- a/compiler/rustc_infer/src/infer/region_constraints/mod.rs +++ b/compiler/rustc_infer/src/infer/region_constraints/mod.rs @@ -8,12 +8,11 @@ use super::{ }; use rustc_data_structures::fx::FxHashMap; -use rustc_data_structures::intern::Interned; use rustc_data_structures::sync::Lrc; use rustc_data_structures::undo_log::UndoLogs; use rustc_data_structures::unify as ut; use rustc_index::IndexVec; -use rustc_middle::infer::unify_key::{RegionVidKey, UnifiedRegion}; +use rustc_middle::infer::unify_key::{RegionVariableValue, RegionVidKey}; use rustc_middle::ty::ReStatic; use rustc_middle::ty::{self, Ty, TyCtxt}; use rustc_middle::ty::{ReBound, ReVar}; @@ -292,6 +291,18 @@ type CombineMap<'tcx> = FxHashMap<TwoRegions<'tcx>, RegionVid>; #[derive(Debug, Clone, Copy)] pub struct RegionVariableInfo { pub origin: RegionVariableOrigin, + // FIXME: This is only necessary for `fn take_and_reset_data` and + // `lexical_region_resolve`. We should rework `lexical_region_resolve` + // in the near/medium future anyways and could move the unverse info + // for `fn take_and_reset_data` into a separate table which is + // only populated when needed. + // + // For both of these cases it is fine that this can diverge from the + // actual universe of the variable, which is directly stored in the + // unification table for unknown region variables. At some point we could + // stop emitting bidirectional outlives constraints if equate succeeds. + // This would be currently unsound as it would cause us to drop the universe + // changes in `lexical_region_resolve`. pub universe: ty::UniverseIndex, } @@ -395,7 +406,11 @@ impl<'tcx> RegionConstraintCollector<'_, 'tcx> { // `RegionConstraintData` contains the relationship here. if *any_unifications { *any_unifications = false; - self.unification_table_mut().reset_unifications(|_| UnifiedRegion::new(None)); + // Manually inlined `self.unification_table_mut()` as `self` is used in the closure. + ut::UnificationTable::with_log(&mut self.storage.unification_table, &mut self.undo_log) + .reset_unifications(|key| RegionVariableValue::Unknown { + universe: self.storage.var_infos[key.vid].universe, + }); } data @@ -422,18 +437,13 @@ impl<'tcx> RegionConstraintCollector<'_, 'tcx> { ) -> RegionVid { let vid = self.var_infos.push(RegionVariableInfo { origin, universe }); - let u_vid = self.unification_table_mut().new_key(UnifiedRegion::new(None)); + let u_vid = self.unification_table_mut().new_key(RegionVariableValue::Unknown { universe }); assert_eq!(vid, u_vid.vid); self.undo_log.push(AddVar(vid)); debug!("created new region variable {:?} in {:?} with origin {:?}", vid, universe, origin); vid } - /// Returns the universe for the given variable. - pub(super) fn var_universe(&self, vid: RegionVid) -> ty::UniverseIndex { - self.var_infos[vid].universe - } - /// Returns the origin for the given variable. pub(super) fn var_origin(&self, vid: RegionVid) -> RegionVariableOrigin { self.var_infos[vid].origin @@ -467,26 +477,41 @@ impl<'tcx> RegionConstraintCollector<'_, 'tcx> { pub(super) fn make_eqregion( &mut self, origin: SubregionOrigin<'tcx>, - sub: Region<'tcx>, - sup: Region<'tcx>, + a: Region<'tcx>, + b: Region<'tcx>, ) { - if sub != sup { + if a != b { // Eventually, it would be nice to add direct support for // equating regions. - self.make_subregion(origin.clone(), sub, sup); - self.make_subregion(origin, sup, sub); - - match (sub, sup) { - (Region(Interned(ReVar(sub), _)), Region(Interned(ReVar(sup), _))) => { - debug!("make_eqregion: unifying {:?} with {:?}", sub, sup); - self.unification_table_mut().union(*sub, *sup); - self.any_unifications = true; + self.make_subregion(origin.clone(), a, b); + self.make_subregion(origin, b, a); + + match (a.kind(), b.kind()) { + (ty::ReVar(a), ty::ReVar(b)) => { + debug!("make_eqregion: unifying {:?} with {:?}", a, b); + if self.unification_table_mut().unify_var_var(a, b).is_ok() { + self.any_unifications = true; + } + } + (ty::ReVar(vid), _) => { + debug!("make_eqregion: unifying {:?} with {:?}", vid, b); + if self + .unification_table_mut() + .unify_var_value(vid, RegionVariableValue::Known { value: b }) + .is_ok() + { + self.any_unifications = true; + }; } - (Region(Interned(ReVar(vid), _)), value) - | (value, Region(Interned(ReVar(vid), _))) => { - debug!("make_eqregion: unifying {:?} with {:?}", vid, value); - self.unification_table_mut().union_value(*vid, UnifiedRegion::new(Some(value))); - self.any_unifications = true; + (_, ty::ReVar(vid)) => { + debug!("make_eqregion: unifying {:?} with {:?}", a, vid); + if self + .unification_table_mut() + .unify_var_value(vid, RegionVariableValue::Known { value: a }) + .is_ok() + { + self.any_unifications = true; + }; } (_, _) => {} } @@ -603,18 +628,21 @@ impl<'tcx> RegionConstraintCollector<'_, 'tcx> { tcx: TyCtxt<'tcx>, vid: ty::RegionVid, ) -> ty::Region<'tcx> { - let mut ut = self.unification_table_mut(); // FIXME(rust-lang/ena#42): unnecessary mut + let mut ut = self.unification_table_mut(); let root_vid = ut.find(vid).vid; - let resolved = ut - .probe_value(root_vid) - .get_value_ignoring_universes() - .unwrap_or_else(|| ty::Region::new_var(tcx, root_vid)); - - // Don't resolve a variable to a region that it cannot name. - if self.var_universe(vid).can_name(self.universe(resolved)) { - resolved - } else { - ty::Region::new_var(tcx, vid) + match ut.probe_value(root_vid) { + RegionVariableValue::Known { value } => value, + RegionVariableValue::Unknown { .. } => ty::Region::new_var(tcx, root_vid), + } + } + + pub fn probe_value( + &mut self, + vid: ty::RegionVid, + ) -> Result<ty::Region<'tcx>, ty::UniverseIndex> { + match self.unification_table_mut().probe_value(vid) { + RegionVariableValue::Known { value } => Ok(value), + RegionVariableValue::Unknown { universe } => Err(universe), } } @@ -654,7 +682,7 @@ impl<'tcx> RegionConstraintCollector<'_, 'tcx> { new_r } - pub fn universe(&self, region: Region<'tcx>) -> ty::UniverseIndex { + pub fn universe(&mut self, region: Region<'tcx>) -> ty::UniverseIndex { match *region { ty::ReStatic | ty::ReErased @@ -662,7 +690,10 @@ impl<'tcx> RegionConstraintCollector<'_, 'tcx> { | ty::ReEarlyParam(..) | ty::ReError(_) => ty::UniverseIndex::ROOT, ty::RePlaceholder(placeholder) => placeholder.universe, - ty::ReVar(vid) => self.var_universe(vid), + ty::ReVar(vid) => match self.probe_value(vid) { + Ok(value) => self.universe(value), + Err(universe) => universe, + }, ty::ReBound(..) => bug!("universe(): encountered bound region {:?}", region), } } |