bug #504: in "datetime op int" comparison int wasn't converted to datetime

mysql-test/r/type_datetime.result

@@ -52,10 +52,17 @@ a
 0000-00-00 00:00:00
 drop table t1;
 create table t1 (id int, dt datetime);
-insert into t1 values (1,"2001-08-14 00:00:00"),(2,"2001-08-15 00:00:00"),(3,"2001-08-16 00:00:00");
+insert into t1 values (1,"2001-08-14 00:00:00"),(2,"2001-08-15 00:00:00"),(3,"2001-08-16 00:00:00"),(4,"2003-09-15 01:20:30");
 select * from t1 where dt='2001-08-14 00:00:00' and dt =  if(id=1,'2001-08-14 00:00:00','1999-08-15');
 id	dt
 1	2001-08-14 00:00:00
+create index dt on t1 (dt);
+select * from t1 where dt > 20021020;
+id	dt
+4	2003-09-15 01:20:30
+select * from t1 ignore index (dt) where dt > 20021020;
+id	dt
+4	2003-09-15 01:20:30
 drop table t1;
 CREATE TABLE `t1` (
 `date` datetime NOT NULL default '0000-00-00 00:00:00',

mysql-test/t/type_datetime.test

@@ -36,8 +36,11 @@ drop table t1;
 #
 
 create table t1 (id int, dt datetime);
-insert into t1 values (1,"2001-08-14 00:00:00"),(2,"2001-08-15 00:00:00"),(3,"2001-08-16 00:00:00");
+insert into t1 values (1,"2001-08-14 00:00:00"),(2,"2001-08-15 00:00:00"),(3,"2001-08-16 00:00:00"),(4,"2003-09-15 01:20:30");
 select * from t1 where dt='2001-08-14 00:00:00' and dt =  if(id=1,'2001-08-14 00:00:00','1999-08-15');
+create index dt on t1 (dt);
+select * from t1 where dt > 20021020;
+select * from t1 ignore index (dt) where dt > 20021020;
 drop table t1;
 
 #

sql/item_cmpfunc.cc

@@ -46,7 +46,7 @@ longlong Item_func_not::val_int()
 
 static bool convert_constant_item(Field *field, Item **item)
 {
-  if ((*item)->const_item() && (*item)->type() != Item::INT_ITEM)
+  if ((*item)->const_item())
   {
     if (!(*item)->save_in_field(field, 1) &&
 	!((*item)->null_value))