Stored procedure execution fails if contains a functional index

DROP PROCEDURE IF EXISTS `sproc`;
DELIMITER $$
CREATE PROCEDURE `sproc`()
BEGIN
DROP TEMPORARY TABLE IF EXISTS `T1`;
CREATE TEMPORARY TABLE `T1`(
`C1` INT,
KEY ( ( `C1` > 0 ) )
);

SELECT 1 FROM ( SELECT 1 `C2` ) `T2`;
END$$
DELIMITER ;

mysql> CALL `sproc`(); CALL `sproc`(); CALL `sproc`();
+---+           
| 1 |           
+---+           
| 1 |           
+---+
1 row in set (0.00 sec)

Query OK, 0 rows affected (0.00 sec)
                
+---+           
| 1 |           
+---+           
| 1 |       
+---+
1 row in set (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

ERROR 3107 (HY000): Generated column can refer only to generated columns defined prior to it.

ERROR 3754 (HY000): Functional index 'functional_index' cannot refer to an auto-increment column.