fixed row union processing

mysql-test/r/subselect.result:
  row union test
mysql-test/t/subselect.test:
  row union test

mysql-test/r/subselect.result

@@ -1361,3 +1361,11 @@ userid	pmtotal	pmnew	calc_total	calc_new
 1	0	0	9	3
 2	0	0	4	2
 drop table t1, t2;
+create table t1 (s1 char(5));
+select (select 'a','b' from t1 union select 'a','b' from t1) from t1;
+ERROR 21000: Cardinality error (more/less than 1 columns)
+insert into t1 values ('tttt');
+select * from t1 where ('a','b')=(select 'a','b' from t1 union select 'a','b' from t1);
+s1
+tttt
+drop table t1;

mysql-test/t/subselect.test

@@ -922,3 +922,13 @@ insert into t2 values(1,0,0),(2,0,0);
 insert into t1 values(1,0),(1,0),(1,0),(1,12),(1,15),(1,123),(1,12312),(1,12312),(1,123),(2,0),(2,0),(2,1),(2,2);
 select userid,pmtotal,pmnew, (select count(rd) from t1 where toid=t2.userid) calc_total, (select count(rd) from t1 where rd=0 and toid=t2.userid) calc_new from t2 where userid in (select distinct toid from t1);
 drop table t1, t2;
+
+#
+# row union
+#
+create table t1 (s1 char(5));
+-- error 1240
+select (select 'a','b' from t1 union select 'a','b' from t1) from t1;
+insert into t1 values ('tttt');
+select * from t1 where ('a','b')=(select 'a','b' from t1 union select 'a','b' from t1);
+drop table t1;

sql/item_subselect.cc

@@ -846,7 +846,7 @@ void subselect_union_engine::fix_length_and_dec(Item_cache **row)
     SELECT_LEX *sl= unit->first_select();
     bool fake= 0;
     res_type= set_row(sl, item, row, &fake);
-    for (sl= sl->next_select(); sl; sl->next_select())
+    for (sl= sl->next_select(); sl; sl= sl->next_select())
     {
       List_iterator_fast<Item> li(sl->item_list);
       Item *sel_item;