Description:
------------
When try converter $this to string, one Catchable fatal error occur.
$this to int, only Notice...

Reproduce code:
---------------
<?php
error_reporting(E_ALL);

class foo
{
  public $test = 'foo';

  public function __construct()
  {
      $this++; // don't convert
      ++$this; // don't convert

      //$this .= '';
      // Catchable fatal error: Object of class foo could not be converted to string    
      
      $this += 1;
      // Notice: Object of class foo could not be converted to int
      
      var_dump($this); //int(2)
      
      // $this->$this;
      // Odd... Notice: Undefined property:  foo::$2
      
      var_dump($this->test); // foo
      
      var_dump($this); // int(2)
  }
}

new foo;


Expected result:
----------------
Catchable fatal error: Object of class foo could not be converted to int

Actual result:
--------------
Notice: Object of class foo could not be converted to int in /home/felipe/public_html/bug.php on line 16
int(2)
string(3) "foo"
int(2)