Reproducing code, expected line 6 to also be covered:

<?php

xdebug_start_code_coverage();
$mapped = array_map(
// This line is flagged as executable, but not covered in PHPUnit code coverage reports
function ( $value )
{
return $value;
},
array( 23, 42 )
);

var_dump( xdebug_get_code_coverage() );
// array(1) {
// ["test.php"] => array(7) {
// [0 ] => int(1)
// [4 ] => int(1)
// [8 ] => int(1)
// [9 ] => int(1)
// [10] => int(1)
// [11] => int(1)
// [13] => int(1)
// }
// }