MDEV-26423 MariaDB server crash in Create_tmp_table::finalize

Removed prohibition of creating temporary field of Item_default_value
(added by mistake by 1d9b043a fix of
MDEV-10780 and MDEV-11265).

mysql-test/r/default.result

@@ -3404,4 +3404,13 @@ ERROR 01000: Expression for field `a` is referring to uninitialized field `a`
 show warnings;
 Level	Code	Message
 Error	4029	Expression for field `a` is referring to uninitialized field `a`
+#
+# MDEV-26423: MariaDB server crash in Create_tmp_table::finalize
+#
+CREATE TABLE t1 (pk varchar(36) DEFAULT uuid());
+INSERT INTO t1 VALUES (),();
+SELECT 1 FROM t1 GROUP BY DEFAULT(pk);
+1
+1
+DROP TABLE t1;
 # end of 10.2 test

mysql-test/r/default_innodb.result

+#
+# MDEV-26423: MariaDB server crash in Create_tmp_table::finalize
+#
+CREATE TABLE v0 (
+v2 DATE DEFAULT ( v1 MOD 68321183.000000 ) ,
+v1 DATETIME NULL ) engine=innodb;
+SHOW DATABASES LIKE 'x';
+Database (x)
+SELECT DISTINCT v2 , v1 , DEFAULT ( v2 ) FROM v0;
+v2	v1	DEFAULT ( v2 )
+DROP TABLE v0;
+CREATE TABLE t1 (v1 DATE, v2 DATE DEFAULT(v1)) engine=innodb;
+SELECT DISTINCT DEFAULT(v2) FROM t1 ;
+DEFAULT(v2)
+DROP TABLE t1;
+#
+# End of 10.2 tests
+#

mysql-test/t/default.test

@@ -2116,4 +2116,13 @@ DROP TABLE t1;
 create table t1 (a int as (a));
 show warnings;
 
+
+--echo #
+--echo # MDEV-26423: MariaDB server crash in Create_tmp_table::finalize
+--echo #
+
+CREATE TABLE t1 (pk varchar(36) DEFAULT uuid());
+INSERT INTO t1 VALUES (),();
+SELECT 1 FROM t1 GROUP BY DEFAULT(pk);
+DROP TABLE t1;
 --echo # end of 10.2 test

mysql-test/t/default_innodb.test

+
+--source include/have_innodb.inc
+
+--echo #
+--echo # MDEV-26423: MariaDB server crash in Create_tmp_table::finalize
+--echo #
+
+CREATE TABLE v0 (
+  v2 DATE DEFAULT ( v1 MOD 68321183.000000 ) ,
+  v1 DATETIME NULL ) engine=innodb;
+SHOW DATABASES LIKE 'x';
+SELECT DISTINCT v2 , v1 , DEFAULT ( v2 ) FROM v0;
+DROP TABLE v0;
+
+CREATE TABLE t1 (v1 DATE, v2 DATE DEFAULT(v1)) engine=innodb;
+SELECT DISTINCT DEFAULT(v2) FROM t1 ;
+DROP TABLE t1;
+
+
+--echo #
+--echo # End of 10.2 tests
+--echo #

sql/item.h

@@ -5502,7 +5502,6 @@ class Item_default_value : public Item_field
     if (field && field->default_value)
       field->default_value->expr->update_used_tables();
   }
-  Field *get_tmp_table_field() { return 0; }
   Item *get_tmp_table_item(THD *thd) { return this; }
   Item_field *field_for_view_update() { return 0; }
   bool update_vcol_processor(void *arg) { return 0; }