[#MDEV-20734] Allow reserved keywords as user defined type names

To avoid compatibility problems in the future, let's allow non-conflicting reserved keywords as user defined type (UDT) names.

This will allow to avoid backticking of user-defined data type names in SHOW CREATE TABLE and mysqldump.

CREATE TABLE t1 (a `udt`);

CREATE TABLE t1 (a udt);

The list of tokens that cannot be used as UDT names (because they cause grammar conflicts with built-in data type names) in 10.5 includes:

All other reserved keywords do not cause conflicts and can be used as UDT names.

CREATE TABLE t1 (a DUAL);

SELECT CAST(a AS DUAL);

ERROR 1064 (42000): You have an error in your SQL syntax .. near 'DUAL)' at line 1

After this change, the query will pass the parser syntactically. A different error will be returned:

ERROR 4161 (HY000): Unknown data type: 'DUAL'

[MDEV-20734] Allow reserved keywords as user defined type names Created: 2019-10-03 Updated: 2019-10-03 Resolved: 2019-10-03
Status:	Closed
Project:	MariaDB Server
Component/s:	Data types, Parser
Fix Version/s:	10.5.0