Description:
------------
I have a class with a static property of type array. This array starts with a key/value pair with a numeric key (value 1 defined in a constant) used to start the indexing. After that, just another two values, expecting the keys to be autogenerated after the initial index.
I expect the array keys to be correlative starting from 1, and to 3. But the array has only two keys starting from 0, and to 1.

I attached a test script, for the script I expect the output to be:
array (
  1 => 'first',
  2 => 'second',
  3 => 'third',
)
but, instead I get:
array (
  0 => 'second',
  1 => 'third',
)
I tested it using [] and array() and get the same results.
It only happens when using self:: followed by constant name as first key in the static property, the next two code portions works as expected, both inside or outside of the class:
    $arr = array(
	1 => 'a',
	'b',
	'c'
    );

$arr = array(
	Test::FIRST	=> 'd',
	'e',
	'f'
);

Test script:
---------------
class Test
{
    const FIRST = 1;
    const SECOND = 2;
    const THIRD = 3;

    protected static $array = [
        self::FIRST => 'first',
        'second',
        'third'
    ];

    public function __construct()
    {
        var_export(self::$array);
    }
}

$test = new Test();


Expected result:
----------------
array (
  1 => 'first',
  2 => 'second',
  3 => 'third',
)

Actual result:
--------------
array (
  0 => 'second',
  1 => 'third',
)