auto merge of #8411 : bblum/rust/assorted-fixes, r=brson

Each commit is pretty much what it says on the tin. r anybody.

1 files changed, 4 insertions, 6 deletions

diff --git a/src/libstd/rt/task.rs b/src/libstd/rt/task.rs
index b50e794cce0..c669f25d8b7 100644
--- a/src/libstd/rt/task.rs
+++ b/src/libstd/rt/task.rs
@@ -253,12 +253,10 @@ impl Task {
             }
         }
 
-        // FIXME(#7544): We pass the taskgroup into death so that it can be
-        // dropped while the unkillable counter is set. This should not be
-        // necessary except for an extraneous clone() in task/spawn.rs that
-        // causes a killhandle to get dropped, which mustn't receive a kill
-        // signal since we're outside of the unwinder's try() scope.
-        // { let _ = self.taskgroup.take(); }
+        // NB. We pass the taskgroup into death so that it can be dropped while
+        // the unkillable counter is set. This is necessary for when the
+        // taskgroup destruction code drops references on KillHandles, which
+        // might require using unkillable (to synchronize with an unwrapper).
         self.death.collect_failure(!self.unwinder.unwinding, self.taskgroup.take());
         self.destroyed = true;
     }