diff --git a/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/ConstantFoldingRule.java b/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/ConstantFoldingRule.java
index 4a1f1fa..769ede3 100644
--- a/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/ConstantFoldingRule.java
+++ b/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/ConstantFoldingRule.java
@@ -174,6 +174,7 @@
             if (expr.getFunctionIdentifier().equals(AsterixBuiltinFunctions.UNORDERED_LIST_CONSTRUCTOR)
                     || expr.getFunctionIdentifier().equals(AsterixBuiltinFunctions.ORDERED_LIST_CONSTRUCTOR)) {
                 AbstractCollectionType listType = (AbstractCollectionType) TypeComputerUtilities.getRequiredType(expr);
+                // do not fold open lists nor nested lists
                 if (listType != null
                         && (listType.getItemType().getTypeTag() == ATypeTag.ANY || listType.getItemType() instanceof AbstractCollectionType)) {
                     return new Pair<Boolean, ILogicalExpression>(false, null);
diff --git a/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/typecast/StaticTypeCastUtil.java b/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/typecast/StaticTypeCastUtil.java
index a361b48..7be6936 100644
--- a/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/typecast/StaticTypeCastUtil.java
+++ b/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/typecast/StaticTypeCastUtil.java
@@ -202,6 +202,15 @@
         return true;
     }
 
+    /**
+     * This method statically cast the type of records from their current type to the required type.
+     * 
+     * @param func The record constructor expression.
+     * @param reqType  The required type.
+     * @param inputType The current type.
+     * @param env The type environment.
+     * @throws AlgebricksException
+     */
     private static void staticRecordTypeCast(AbstractFunctionCallExpression func, ARecordType reqType,
             ARecordType inputType, IVariableTypeEnvironment env) throws AlgebricksException {
         IAType[] reqFieldTypes = reqType.getFieldTypes();