WIPvariance

tools/analysis/traceevent/src/buffer.rs

@@ -303,13 +303,13 @@ where
                 // tried to get the event_desc before and it failed.
                 let desc_map = self.desc_map().ok_or_else(not_found)?;
                 let (desc, user) = desc_map.lookup(event_id).ok_or_else(not_found)?;
-                Ok((desc as *const EventDesc, user))
-            }).map(|(desc, user): &(*const EventDesc, *const T)| {
+                Ok((desc, user))
+            }).map(|(desc, user)| {
                 let user: *const T = *user;
                 let desc: *const EventDesc = *desc;
-                // SAFETY: EventDescMap contains &'h EventDesc, which we store as *const EventDesc
-                // to avoid variance issues. It's therefore completely safe to just cast it back to
-                // &'h EventDesc.
+                // SAFETY: EventDescMap::lookup() returns (&'h EventDesc, &'edm T), which we store
+                // as (*const EventDesc, *const T) to avoid variance issues. It's therefore
+                // completely safe to just cast it back to &'h EventDesc.
                 let desc: &'h EventDesc = unsafe{ &*desc };
                 let user: &'edm T = unsafe{ &*user};
                 (desc, user)