COLLATE option not accepted in generated column definition

This bug fixed in MySQL 5.7.6 onwards also happens in MariaDB 10.3.17:

https://bugs.mysql.com/bug.php?id=76329

Inital Report from Mario Beck:

[15 Mar 2015 21:07] Mario Beck

Description:
When defining a generated column and the datatype is CHAR or VARCHAR (TEXT probably as well?) it is possible to define a character set but it is not possible to define a collation.

How to repeat:
CREATE TABLE bla (i int);
ALTER TABLE bla ADD COLUMN t CHAR(42) CHARACTER SET utf8 COLLATE utf8_bin GENERATED ALWAYS AS ("foo bar");

Same statement without the COLLATE option works fine.