INSERT silently truncates too long value for a virtual column without warnings or errors

CREATE TABLE t1 (a VARCHAR(3), v VARCHAR(3) AS (CONCAT('x-',a)) VIRTUAL);

INSERT INTO t1 (a) VALUES ('foo');

SELECT * FROM t1;

INSERT INTO t1 (a) VALUES ('foo');

SELECT * FROM t1;

a	v

foo	x-f

INSERT INTO t1 (a) VALUES ('foo');

Warnings:

Warning	1265	Data truncated for column 'v' at row 1

SELECT * FROM t1;

a	v

foo	x-f

mysqltest: At line 2: query 'INSERT INTO t1 (a) VALUES ('foo')' failed: 1406: Data too long for column 'v' at row 1