Description:
------------
Assume a class with overload-support.
Now, if you use an instance of that class to __set/__get a property (of type string) an try to concatenate it with the return value of another function (which returns a string like session_id()) some strange things gonna happen. The actual return value (of the string-returning function, session_id() in this example) will be changed to '1'!

(see code and the actual/expected results... notice, that the session_id may differ, but it's never expected to give '1' as a session_id)

However, if a constant string (or if the return value is temporarily stored into another variable) is concatenated to the property, everthing works fine (see comments in the code). 

PHP configuration is:
 - Win 2000 SP4
 - minixampp containing
    - Apache/2.0.48 (Win32) 
    - PHP/4.3.4



Reproduce code:
---------------
<?php

class A {
  function A() {
    echo "A constructed<br>\n";
  }
	
  function __get($key, &$value) {
    $value = $_SESSION[$key];
    echo "__get was called with '$key' <br>\n";
    return true;
  }
	
  function __set($key, $value) {
    $_SESSION[$key] = $value;
    echo "__set was called with '$key' = '$value' <br>\n";
    return true;
  }
}
overload('A');

session_name("my_session");
session_start(); # make sure, a session is started
$a =& new A();
$a->my_var = "test";
$res = $a->my_var.session_id(); # <- doesn't work properly!

# the following one will work as expected
# $res = $a->my_var."_constant_string"; 
# (produces output: "test_constant_string")
# this one is ok, too:
# $res = $a->my_var."".session_id();

echo "concat test :".$res."<br>\n";
echo "session id  : ".session_id()."<br>\n";
?>

Expected result:
----------------
A constructed
__set was called with 'my_var' = 'test' 
__get was called with 'my_var' 
concat-test : test31b4ed95c6d107d9e40368c160843d8e
session id : 31b4ed95c6d107d9e40368c160843d8e


Actual result:
--------------
A constructed
__set was called with 'my_var' = 'test' 
__get was called with 'my_var' 
concat-test : test1
session id : 31b4ed95c6d107d9e40368c160843d8e