--- a/tools/profiler/lul/LulDwarf.cpp
+++ b/tools/profiler/lul/LulDwarf.cpp
@@ -596,17 +596,17 @@ bool CallFrameInfo::RuleMap::HandleTrans
       // state, and there's no way to remove entries.
       MOZ_ASSERT(0);
     } else {
       // Both maps have an entry for this register. Report the new
       // rule if it is different.
       if (*old_it->second != *new_it->second &&
           !new_it->second->Handle(handler, address, new_it->first))
         return false;
-      new_it++, old_it++;
+      new_it++; old_it++;
     }
   }
   // Finish off entries from this RuleMap with no counterparts in new_rules.
   while (old_it != registers_.end()) {
     if (!handler->SameValueRule(address, old_it->first))
       return false;
     old_it++;
   }