Fix off-by-one

Author: pierwill

compiler/rustc_borrowck/src/region_infer/mod.rs

@@ -2046,7 +2046,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         // we still want to screen for an "interesting" point to
         // highlight (e.g., a call site or something).
         let target_scc = self.constraint_sccs.scc(target_region);
-        let mut range = 0..path.len();
+        let mut range = 0..categorized_path.len();
 
         // As noted above, when reporting an error, there is typically a chain of constraints
         // leading from some "source" region which must outlive some "target" region.
@@ -2162,7 +2162,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
             return categorized_path[i].clone();
         }
 
-        categorized_path.shift_remove_index(0).unwrap()
+        return categorized_path[0].clone();
     }
 
     crate fn universe_info(&self, universe: ty::UniverseIndex) -> UniverseInfo<'tcx> {