diff --git a/ast/index_expression.go b/ast/index_expression.go
index 4cd9528..e1e65f1 100644
--- a/ast/index_expression.go
+++ b/ast/index_expression.go
@@ -11,6 +11,8 @@ type IndexExpression struct {
 	Value Expression
 }
 
+func (ie *IndexExpression) validIfCondition() bool { return true }
+
 func (ie *IndexExpression) expressionNode() {}
 
 func (ie *IndexExpression) String() string {
diff --git a/parser/parser_test.go b/parser/parser_test.go
index a5477f5..e8d68ed 100644
--- a/parser/parser_test.go
+++ b/parser/parser_test.go
@@ -397,6 +397,15 @@ func Test_IfExpression_PrefixExpressions_InvalidCompar(t *testing.T) {
 
 	r.Error(err, "syntax error: invalid if condition, got x = 1")
 }
+func Test_IfExpression_With_Map_Array_Index(t *testing.T) {
+	r := require.New(t)
+	input := `<% if (flash["error"] ) { x } %>`
+
+	_, err := Parse(input)
+
+	r.NoError(err)
+}
+
 func Test_IfExpression_InfixExpressions_InvalidCompare(t *testing.T) {
 	r := require.New(t)
 	input := `<% if ( y == 1 && x = 1) { x } %>`