Auto merge of #104765 - chenyukang:yukang-fix-104639-lifetime-check, r=oli-obk

[rust.git] / compiler / rustc_borrowck / src / region_infer / mod.rs

diff --git a/compiler/rustc_borrowck/src/region_infer/mod.rs b/compiler/rustc_borrowck/src/region_infer/mod.rs
index 90e2b6b698cf832ec4a2d45e266e173369a3062f..e9c98bdc514967a63f4f1dc39be0e6be7d1919ed 100644 (file)
--- a/compiler/rustc_borrowck/src/region_infer/mod.rs
+++ b/compiler/rustc_borrowck/src/region_infer/mod.rs
@@ -747,27 +747,14 @@ fn apply_member_constraint(
         // 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);