Subquery's rand() column re-evaluated for every repeated selection in MySQL 5.7 vs MySQL 5.6

[Pavel Sharov]

I am doing a subselect in which I have a column involving random number generation. In the main query I select this column twice. In MySQL 5.6 it works as I expect, the rand() value being fixed. The 5.7 execution looks like rand() is re-evaluated individually for each selection. Is this correct behavior? What should I do in 5.7 to make it work just as in 5.6? I posted this question on StackOverflow (https://stackoverflow.com/questions/44336391/subquerys-rand-column-re-evaluated-for-every-repeated-selection-in-mysql-5-7), there's an opinion in comments there that it is a bug.

CREATE TABLE t (
`id` BIGINT(20) NOT NULL PRIMARY KEY AUTO_INCREMENT
) ENGINE=InnoDB;

insert into t values();
insert into t values();
insert into t values();
insert into t values();
insert into t values();

SELECT q.i, q.r, q.r
FROM (
SELECT
id AS i,
(FLOOR(RAND(100) * 4)) AS r
FROM t
) q;

MySQL 5.6 yields (values are the same):

+---+-----+-----+
| i | r | r |
+---+-----+-----+
| 1 | 0 | 0 |
| 2 | 2 | 2 |
| 3 | 3 | 3 |
| 4 | 2 | 2 |
| 5 | 1 | 1 |
+---+-----+-----+

while 5.7 yields (values are different):

+---+-----+-----+
| i | r | r |
+---+-----+-----+
| 1 | 0 | 2 |
| 2 | 3 | 2 |
| 3 | 1 | 1 |
| 4 | 2 | 1 |
| 5 | 2 | 0 |
+---+-----+-----+