Views based on FROM DUAL selects always evaluate all columns

CREATE OR REPLACE ALGORITHM = MERGE VIEW v AS

SELECT 1 a, SLEEP(3) b, SLEEP(3) c FROM DUAL;

EXPLAIN EXTENDED

SELECT a FROM v;

\W

CREATE OR REPLACE TABLE t (a INT) ENGINE = InnoDB;

INSERT INTO t VALUES (1);

CREATE OR REPLACE ALGORITHM = MERGE VIEW v AS

SELECT a, SLEEP(3) b, SLEEP(3) c FROM t;

EXPLAIN EXTENDED

SELECT a FROM v;