Problems with tracing location in callback-ed functions/methods

Problems with tracing location in callback-ed functions/methods

Exceptions thown in a function/method been called via 'call_user_func' or 'call_user_func_array', have key 'file' and 'line' disappeared in their first element (array[0]) from Exception::getTrace().

getTrace());
}

function callback() {
 call_user_func('test');
}

try {
 callback();
} catch (Exception $e) {
 var_dump($e->getTrace());
}
?>

G:\wwwroot\Test\Exception>php trace_func.php
#0  test() called at [G:\wwwroot\Test\Exception\trace_func.php:8]
array(1) {
  [0]=>
  array(4) {
    ["file"]=>
    string(40) "G:\wwwroot\Test\Exception\trace_func.php"
    ["line"]=>
    int(8)
    ["function"]=>
    string(4) "test"
    ["args"]=>
    array(0) {
    }
  }
}
#0  test()
#1  call_user_func(test) called at [G:\wwwroot\Test\Exception\trace_func.php:14]
#2  callback() called at [G:\wwwroot\Test\Exception\trace_func.php:18]
array(3) {
  [0]=>
  array(2) {
    ["function"]=>
    string(4) "test"
    ["args"]=>
    array(0) {
    }
  }
  [1]=>
  array(4) {
    ["file"]=>
    string(40) "G:\wwwroot\Test\Exception\trace_func.php"
    ["line"]=>
    int(14)
    ["function"]=>
    string(14) "call_user_func"
    ["args"]=>
    array(1) {
      [0]=>
      string(4) "test"
    }
  }
  [2]=>
  array(4) {
    ["file"]=>
    string(40) "G:\wwwroot\Test\Exception\trace_func.php"
    ["line"]=>
    int(18)
    ["function"]=>
    string(8) "callback"
    ["args"]=>
    array(0) {
    }
  }
}

Similar result given by debug_print_backtrace(), is this a bug or an unexpected feature ? XD