diff --git a/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/IntroduceStaticTypeCastRule.java b/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/IntroduceStaticTypeCastRule.java
index b38e119..1de0b19 100644
--- a/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/IntroduceStaticTypeCastRule.java
+++ b/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/IntroduceStaticTypeCastRule.java
@@ -197,7 +197,7 @@
                     List<Mutable<ILogicalExpression>> expressionRefs = originalAssign.getExpressions();
                     ILogicalExpression expr = expressionRefs.get(position).getValue();
                     if (expr.getExpressionTag() == LogicalExpressionTag.FUNCTION_CALL) {
-                        ScalarFunctionCallExpression funcExpr = (ScalarFunctionCallExpression) expr;
+                        AbstractFunctionCallExpression funcExpr = (AbstractFunctionCallExpression) expr;
                         // that expression has been rewritten, and it will not
                         // fail but just return false
                         if (TypeComputerUtilities.getRequiredType(funcExpr) != null) {