Bug #36995: valgrind error in remove_const during subquery executions

When copying the Item class one must copy its attributes as well.

mysql-test/r/innodb_mysql.result

@@ -1303,4 +1303,16 @@ t1	CREATE TABLE `t1` (
   CONSTRAINT `f2_ref` FOREIGN KEY (`f2`) REFERENCES `t1` (`f1`)
 ) ENGINE=InnoDB DEFAULT CHARSET=latin1
 DROP TABLE t1;
+#
+# Bug #36995: valgrind error in remove_const during subquery executions
+#
+create table t1 (a bit(1) not null,b int) engine=myisam;
+create table t2 (c int) engine=innodb;
+explain
+select b from t1 where a not in (select b from t1,t2 group by a) group by a;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+2	DEPENDENT SUBQUERY	t1	system	NULL	NULL	NULL	NULL	0	const row not found
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	1	
+DROP TABLE t1,t2;
 End of 5.0 tests

mysql-test/t/innodb_mysql.test

@@ -1063,4 +1063,14 @@ CREATE TABLE t1 (f1 INTEGER PRIMARY KEY COMMENT 'My ID#', f2 INTEGER DEFAULT NUL
 SHOW CREATE TABLE t1;
 DROP TABLE t1;
 
+--echo #
+--echo # Bug #36995: valgrind error in remove_const during subquery executions
+--echo #
+
+create table t1 (a bit(1) not null,b int) engine=myisam;
+create table t2 (c int) engine=innodb;
+explain
+select b from t1 where a not in (select b from t1,t2 group by a) group by a;
+DROP TABLE t1,t2;
+
 --echo End of 5.0 tests

sql/item.cc

@@ -409,6 +409,7 @@ Item::Item(THD *thd, Item *item):
   name(item->name),
   orig_name(item->orig_name),
   max_length(item->max_length),
+  name_length(item->name_length),
   marker(item->marker),
   decimals(item->decimals),
   maybe_null(item->maybe_null),
@@ -416,7 +417,9 @@ Item::Item(THD *thd, Item *item):
   unsigned_flag(item->unsigned_flag),
   with_sum_func(item->with_sum_func),
   fixed(item->fixed),
+  is_autogenerated_name(item->is_autogenerated_name),
   collation(item->collation),
+  with_subselect(item->with_subselect),
   cmp_context(item->cmp_context)
 {
   next= thd->free_list;				// Put in free list