enclose else block in terminating scope

Author: dingxiangfei2009

compiler/rustc_typeck/src/check/region.rs

@@ -144,6 +144,7 @@ fn resolve_block<'tcx>(visitor: &mut RegionResolutionVisitor<'tcx>, blk: &'tcx h
                     // the sequence of visits agree with the order in the default
                     // `hir::intravisit` visitor.
                     mem::swap(&mut prev_cx, &mut visitor.cx);
+                    visitor.terminating_scopes.insert(els.hir_id.local_id);
                     visitor.visit_block(els);
                     // From now on, we continue normally.
                     visitor.cx = prev_cx;

src/test/ui/async-await/async-await-let-else.no-drop-tracking.stderr

@@ -35,8 +35,7 @@ LL |         bar2(Rc::new(())).await
    |              |
    |              has type `Rc<()>` which is not `Send`
 LL |     };
-LL | }
-   | - `Rc::new(())` is later dropped here
+   |     - `Rc::new(())` is later dropped here
 note: required by a bound in `is_send`
   --> $DIR/async-await-let-else.rs:19:15
    |