Description:
------------
A segmentation fault is going to happen when you accidentally uses clone inside the jsonSerialize method that implements JsonSerializable and return the new cloned object. If you uncomment the following test script,  you will see that is going to be called several times until the recursive call get exhausted and finish given the segmentation fault.



Test script:
---------------
<?php


class CloneThis implements JsonSerializable {
  public $date;

  public function jsonSerialize() {
        $clone = clone $this;
//      var_dump($this);

//        if ($this->date instanceof DateTime) {
 //               $clone->date = $this->date->format('Y.m.d');
   //     }
        return $clone;
  }
 
}


$variable = new CloneThis;
$variable->date = new DateTime();

echo json_encode($variable);












Expected result:
----------------
I think should be :
 1. or the current date. 
 2. or An error where many recursive calls are done (maybe)


Actual result:
--------------
////////////////////////////////
...strings removed

object(CloneThis)#52273 (1) {
  ["date"]=>
  string(10) "2019.10.12"
}
object(CloneThis)#52274 (1) {
  ["date"]=>
  string(10) "2019.10.12"
}
object(CloneThis)#52275 (1) {
  ["date"]=>
  string(10) "2019.10.12"
}
object(CloneThis)#52276 (1) {
  ["date"]=>
  string(10) "2019.10.12"
}
object(CloneThis)#52277 (1) {
  ["date"]=>
Segment violation