Description:
------------
I had some old code running for years (since PHP 5.3.x). After upgrade it started to segfault in a overwritten offsetGet method in a class implementing ArrayAccess. After debugging it I reached the broken code at following function made long ago:

  public function offsetGet($key)
  {
    if (in_array($key, array_keys($this->_structure), true) && !isset($this[$key]))
    {
      return null;
    }

    return (parent::offsetExists($key)) ? parent::offsetGet($key) : null;
  }

The result at dbg:

Program received signal SIGSEGV, Segmentation fault.
zend_call_method (object_pp=object_pp@entry=0x7fffff7ff078, obj_ce=0x1d14658, fn_proxy=fn_proxy@entry=0x1d5beb0, 
    function_name=function_name@entry=0xb2598c "offsetGet", function_name_len=function_name_len@entry=9, 
    retval_ptr_ptr=retval_ptr_ptr@entry=0x7fffff7ff088, param_count=1, arg1=0x2059d28, arg2=0x0)
    at /build/php5-NIujy4/php5-5.6.4+dfsg/Zend/zend_interfaces.c:47
47      in /build/php5-NIujy4/php5-5.6.4+dfsg/Zend/zend_interfaces.c

I made it work after changing the last tine to:

    return (parent::offsetExists($key)) ? $this->_structure[$key] : null;                                          

Hope that helps.