LivenessValues does not need to be generic over regions

Author: lqd

compiler/rustc_borrowck/src/constraint_generation.rs

@@ -9,7 +9,7 @@ use rustc_middle::mir::{
 };
 use rustc_middle::ty::visit::TypeVisitable;
 use rustc_middle::ty::GenericArgsRef;
-use rustc_middle::ty::{self, RegionVid, Ty, TyCtxt};
+use rustc_middle::ty::{self, Ty, TyCtxt};
 
 use crate::{
     borrow_set::BorrowSet, facts::AllFacts, location::LocationTable, places_conflict,
@@ -18,7 +18,7 @@ use crate::{
 
 pub(super) fn generate_constraints<'tcx>(
     infcx: &InferCtxt<'tcx>,
-    liveness_constraints: &mut LivenessValues<RegionVid>,
+    liveness_constraints: &mut LivenessValues,
     all_facts: &mut Option<AllFacts>,
     location_table: &LocationTable,
     body: &Body<'tcx>,
@@ -43,7 +43,7 @@ struct ConstraintGeneration<'cg, 'tcx> {
     infcx: &'cg InferCtxt<'tcx>,
     all_facts: &'cg mut Option<AllFacts>,
     location_table: &'cg LocationTable,
-    liveness_constraints: &'cg mut LivenessValues<RegionVid>,
+    liveness_constraints: &'cg mut LivenessValues,
     borrow_set: &'cg BorrowSet<'tcx>,
     body: &'cg Body<'tcx>,
 }

compiler/rustc_borrowck/src/region_infer/mod.rs

@@ -59,7 +59,7 @@ pub struct RegionInferenceContext<'tcx> {
     /// regions, these start out empty and steadily grow, though for
     /// each universally quantified region R they start out containing
     /// the entire CFG and `end(R)`.
-    liveness_constraints: LivenessValues<RegionVid>,
+    liveness_constraints: LivenessValues,
 
     /// The outlives constraints computed by the type-check.
     constraints: Frozen<OutlivesConstraintSet<'tcx>>,
@@ -332,7 +332,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         member_constraints_in: MemberConstraintSet<'tcx, RegionVid>,
         universe_causes: FxIndexMap<ty::UniverseIndex, UniverseInfo<'tcx>>,
         type_tests: Vec<TypeTest<'tcx>>,
-        liveness_constraints: LivenessValues<RegionVid>,
+        liveness_constraints: LivenessValues,
         elements: &Rc<RegionValueElements>,
         live_loans: SparseBitMatrix<PointIndex, BorrowIndex>,
     ) -> Self {

compiler/rustc_borrowck/src/region_infer/values.rs

@@ -118,53 +118,57 @@ pub(crate) enum RegionElement {
 
 /// Records the CFG locations where each region is live. When we initially compute liveness, we use
 /// an interval matrix storing liveness ranges for each region-vid.
-pub(crate) struct LivenessValues<N: Idx> {
+pub(crate) struct LivenessValues {
     elements: Rc<RegionValueElements>,
-    points: SparseIntervalMatrix<N, PointIndex>,
+    points: SparseIntervalMatrix<RegionVid, PointIndex>,
 }
 
-impl<N: Idx> LivenessValues<N> {
+impl LivenessValues {
     /// Create an empty map of regions to locations where they're live.
     pub(crate) fn new(elements: Rc<RegionValueElements>) -> Self {
         Self { points: SparseIntervalMatrix::new(elements.num_points), elements }
     }
 
     /// Iterate through each region that has a value in this set.
-    pub(crate) fn regions(&self) -> impl Iterator<Item = N> {
+    pub(crate) fn regions(&self) -> impl Iterator<Item = RegionVid> {
         self.points.rows()
     }
 
     /// Records `region` as being live at the given `location`.
-    pub(crate) fn add_location(&mut self, region: N, location: Location) {
+    pub(crate) fn add_location(&mut self, region: RegionVid, location: Location) {
         debug!("LivenessValues::add_location(region={:?}, location={:?})", region, location);
         let point = self.elements.point_from_location(location);
         self.points.insert(region, point);
     }
 
     /// Records `region` as being live at all the given `points`.
-    pub(crate) fn add_points(&mut self, region: N, points: &IntervalSet<PointIndex>) -> bool {
+    pub(crate) fn add_points(
+        &mut self,
+        region: RegionVid,
+        points: &IntervalSet<PointIndex>,
+    ) -> bool {
         debug!("LivenessValues::add_points(region={:?}, points={:?})", region, points);
         self.points.union_row(region, points)
     }
 
-    /// Record `region` as being live at all the control-flow points.
-    pub(crate) fn add_all_points(&mut self, region: N) {
+    /// Records `region` as being live at all the control-flow points.
+    pub(crate) fn add_all_points(&mut self, region: RegionVid) {
         self.points.insert_all_into_row(region);
     }
 
     /// Returns whether `region` is marked live at the given `location`.
-    pub(crate) fn is_live_at(&self, region: N, location: Location) -> bool {
+    pub(crate) fn is_live_at(&self, region: RegionVid, location: Location) -> bool {
         let point = self.elements.point_from_location(location);
         self.points.row(region).is_some_and(|r| r.contains(point))
     }
 
     /// Returns whether `region` is marked live at any location.
-    pub(crate) fn is_live_anywhere(&self, region: N) -> bool {
+    pub(crate) fn is_live_anywhere(&self, region: RegionVid) -> bool {
         self.live_points(region).next().is_some()
     }
 
     /// Returns an iterator of all the points where `region` is live.
-    fn live_points(&self, region: N) -> impl Iterator<Item = PointIndex> + '_ {
+    fn live_points(&self, region: RegionVid) -> impl Iterator<Item = PointIndex> + '_ {
         self.points
             .row(region)
             .into_iter()
@@ -173,7 +177,7 @@ impl<N: Idx> LivenessValues<N> {
     }
 
     /// Returns a "pretty" string value of the region. Meant for debugging.
-    pub(crate) fn region_value_str(&self, region: N) -> String {
+    pub(crate) fn region_value_str(&self, region: RegionVid) -> String {
         region_value_str(
             self.live_points(region)
                 .map(move |p| RegionElement::Location(self.elements.to_location(p))),
@@ -310,7 +314,7 @@ impl<N: Idx> RegionValues<N> {
     /// `self[to] |= values[from]`, essentially: that is, take all the
     /// elements for the region `from` from `values` and add them to
     /// the region `to` in `self`.
-    pub(crate) fn merge_liveness<M: Idx>(&mut self, to: N, from: M, values: &LivenessValues<M>) {
+    pub(crate) fn merge_liveness(&mut self, to: N, from: RegionVid, values: &LivenessValues) {
         if let Some(set) = values.points.row(from) {
             self.points.union_row(to, set);
         }

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -899,7 +899,7 @@ pub(crate) struct MirTypeckRegionConstraints<'tcx> {
     /// not otherwise appear in the MIR -- in particular, the
     /// late-bound regions that it instantiates at call-sites -- and
     /// hence it must report on their liveness constraints.
-    pub(crate) liveness_constraints: LivenessValues<RegionVid>,
+    pub(crate) liveness_constraints: LivenessValues,
 
     pub(crate) outlives_constraints: OutlivesConstraintSet<'tcx>,