Track https://github.com/mongodb/mongo-php-driver/pull/2212 

Passing a DateTimeInterface subclass whose constructor does not call the parent constructor to MongoDB\BSON\UTCDateTime::__construct() crashes the process with a segmentation fault. The object has no internal time value, and phongo_utcdatetime_init_from_date() dereferences the NULL time pointer.

class MyDateTime extends DateTime
{
    public function __construct() {}
}

new MongoDB\BSON\UTCDateTime(new MyDateTime()); // Segmentation fault