// Otherwise, we need to find the minimum remaining choice, if
// any, and take that.
debug!("choice_regions remaining are {:#?}", choice_regions);
- let min = |r1: ty::RegionVid, r2: ty::RegionVid| -> Option<ty::RegionVid> {
- let r1_outlives_r2 = self.universal_region_relations.outlives(r1, r2);
- let r2_outlives_r1 = self.universal_region_relations.outlives(r2, r1);
- match (r1_outlives_r2, r2_outlives_r1) {
- (true, true) => Some(r1.min(r2)),
- (true, false) => Some(r2),
- (false, true) => Some(r1),
- (false, false) => None,
- }
+ let Some(&min_choice) = choice_regions.iter().find(|&r1| {
+ choice_regions.iter().all(|&r2| {
+ self.universal_region_relations.outlives(r2, *r1)
+ })
+ }) else {
+ debug!("no choice region outlived by all others");
+ return false;
};
- let mut min_choice = choice_regions[0];
- for &other_option in &choice_regions[1..] {
- debug!(?min_choice, ?other_option,);
- match min(min_choice, other_option) {
- Some(m) => min_choice = m,
- None => {
- debug!(?min_choice, ?other_option, "incomparable; no min choice",);
- return false;
- }
- }
- }
let min_choice_scc = self.constraint_sccs.scc(min_choice);
debug!(?min_choice, ?min_choice_scc);