diff --git a/arangod/Aql/OptimizerRules.cpp b/arangod/Aql/OptimizerRules.cpp
index 7804e64cf2..395d140326 100644
--- a/arangod/Aql/OptimizerRules.cpp
+++ b/arangod/Aql/OptimizerRules.cpp
@@ -135,10 +135,7 @@ int triagens::aql::moveCalculationsUpRule (Optimizer* opt,
       continue;
     }
 
-    auto neededVars = n->getVariablesUsedHere();
-    // sort the list of variables that the expression needs as its input
-    // (sorting is needed for intersection later)
-    std::sort(neededVars.begin(), neededVars.end(), &Variable::Comparator);
+    auto const neededVars = n->getVariablesUsedHere();
 
     std::vector<ExecutionNode*> stack;
     for (auto dep : n->getDependencies()) {
@@ -260,7 +257,7 @@ int triagens::aql::moveFiltersUpRule (Optimizer* opt,
 
       // first, unlink the filter from the plan
       plan->unlinkNode(n);
-      // and re-insert into before the current node
+      // and re-insert into plan in front of the current node
       plan->insertDependency(current, n);
       modified = true;
     }