Script:

<?php

xdebug_start_code_coverage(XDEBUG_CC_UNUSED);

function test()
{
substr('', 2,
0 + 3 + 0
);
}

test();

print_r(xdebug_get_code_coverage());

Actual Result:

Array
(
[code_coverage.php] => Array
(
[5] => 1
[7] => 1
[8] => -1
[9] => 1
[10] => 1
[12] => 1
[14] => 1
)

)

Expected Result:

Array
(
[code_coverage.php] => Array
(
[5] => 1
[7] => 1
[8] => 1
[9] => 1
[10] => 1
[12] => 1
[14] => 1
)

)