diff --git a/compiler/rustc_borrowck/src/region_infer/reverse_sccs.rs b/compiler/rustc_borrowck/src/region_infer/reverse_sccs.rs index b2ed8a358279..8e04791461b2 100644 --- a/compiler/rustc_borrowck/src/region_infer/reverse_sccs.rs +++ b/compiler/rustc_borrowck/src/region_infer/reverse_sccs.rs @@ -7,6 +7,8 @@ use rustc_middle::ty::RegionVid; use crate::RegionInferenceContext; use crate::constraints::ConstraintSccIndex; +use crate::region_infer::ConstraintSccs; +use crate::universal_regions::UniversalRegions; pub(crate) struct ReverseSccGraph { graph: VecGraph, @@ -19,6 +21,29 @@ pub(crate) struct ReverseSccGraph { } impl ReverseSccGraph { + pub(super) fn compute( + constraint_sccs: &ConstraintSccs, + universal_regions: &UniversalRegions<'_>, + ) -> Self { + let graph = constraint_sccs.reverse(); + let mut paired_scc_regions = universal_regions + .universal_regions_iter() + .map(|region| (constraint_sccs.scc(region), region)) + .collect::>(); + paired_scc_regions.sort(); + let universal_regions = paired_scc_regions.iter().map(|&(_, region)| region).collect(); + + let mut scc_regions = FxIndexMap::default(); + let mut start = 0; + for chunk in paired_scc_regions.chunk_by(|&(scc1, _), &(scc2, _)| scc1 == scc2) { + let (scc, _) = chunk[0]; + + scc_regions.insert(scc, start..start + chunk.len()); + start += chunk.len(); + } + ReverseSccGraph { graph, scc_regions, universal_regions } + } + /// Find all universal regions that are required to outlive the given SCC. pub(super) fn upper_bounds(&self, scc0: ConstraintSccIndex) -> impl Iterator { let mut duplicates = FxIndexSet::default(); @@ -40,23 +65,7 @@ impl RegionInferenceContext<'_> { return; } - let graph = self.constraint_sccs.reverse(); - let mut paired_scc_regions = self - .universal_regions() - .universal_regions_iter() - .map(|region| (self.constraint_sccs.scc(region), region)) - .collect::>(); - paired_scc_regions.sort(); - let universal_regions = paired_scc_regions.iter().map(|&(_, region)| region).collect(); - - let mut scc_regions = FxIndexMap::default(); - let mut start = 0; - for chunk in paired_scc_regions.chunk_by(|&(scc1, _), &(scc2, _)| scc1 == scc2) { - let (scc, _) = chunk[0]; - scc_regions.insert(scc, start..start + chunk.len()); - start += chunk.len(); - } - - self.rev_scc_graph = Some(ReverseSccGraph { graph, scc_regions, universal_regions }); + self.rev_scc_graph = + Some(ReverseSccGraph::compute(&self.constraint_sccs, self.universal_regions())); } }