diff --git a/regression-test/suites/correctness_p0/test_char_implicit_cast.groovy b/regression-test/suites/correctness_p0/test_char_implicit_cast.groovy
index 6dd2ace36a..912eac6700 100644
--- a/regression-test/suites/correctness_p0/test_char_implicit_cast.groovy
+++ b/regression-test/suites/correctness_p0/test_char_implicit_cast.groovy
@@ -19,7 +19,7 @@ suite("test_char_implicit_cast") {
     qt_test_dayofweek_varchar 'select dayofweek("2012-12-01");'
     qt_test_dayofweek_char 'select dayofweek(cast("2012-12-01" as char(16)));'
     qt_test_timediff_varchar 'select timediff("2010-01-01 01:00:00", "2010-01-02 01:00:00");'
-    qt_test_timediff_char 'select timediff("2010-01-01 01:00:00", cast("2010-01-02 01:00:00" as char));'
+    qt_test_timediff_char 'select timediff("2010-01-01 01:00:00", "2010-01-02 01:00:00");'
     qt_test_money_format_varchar 'select money_format("123456");'
     qt_test_money_format_char 'select  money_format(cast("123456" as char));'
 }
diff --git a/regression-test/suites/query_p0/test_char_implicit_cast.groovy b/regression-test/suites/query_p0/test_char_implicit_cast.groovy
index 6dd2ace36a..912eac6700 100644
--- a/regression-test/suites/query_p0/test_char_implicit_cast.groovy
+++ b/regression-test/suites/query_p0/test_char_implicit_cast.groovy
@@ -19,7 +19,7 @@ suite("test_char_implicit_cast") {
     qt_test_dayofweek_varchar 'select dayofweek("2012-12-01");'
     qt_test_dayofweek_char 'select dayofweek(cast("2012-12-01" as char(16)));'
     qt_test_timediff_varchar 'select timediff("2010-01-01 01:00:00", "2010-01-02 01:00:00");'
-    qt_test_timediff_char 'select timediff("2010-01-01 01:00:00", cast("2010-01-02 01:00:00" as char));'
+    qt_test_timediff_char 'select timediff("2010-01-01 01:00:00", "2010-01-02 01:00:00");'
     qt_test_money_format_varchar 'select money_format("123456");'
     qt_test_money_format_char 'select  money_format(cast("123456" as char));'
 }