Description:
------------
As of 7.1 rand() is mostly an alias of mt_rand.

This is explained in the doc notes http://php.net/manual/en/function.rand.php.

However it does have some difference to preserve BC.

See also the user note @ http://php.net/manual/en/function.rand.php#120782:

From PHP 7.1 rand() is documented as an alias of mt_rand().

Actually, if they are called with two arguments where the second is smaller than the first, their output differs.

For example

var_dump(rand(2,1), mt_rand(2,1));

may return

Warning: mt_rand(): max(1) is smaller than min(2)
int(2)
bool(false)

where rand() will return a random value between $max and $min


Expected result:
----------------
Clarify taht rand() isn't an exact alias.