Description:
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well, I am trying to define constants in a file called config.php then I wanna use it in a file called "debug.php". 
I defined a variable like 
$test="test". 
then call this variable by 
echo $test; 
in "debug.php".
it never works..
but if I rename the config.php to other names like"config1.php", it works. 

I dont know why that happens? it's reserved file name or something?

Thanks.

Reproduce code:
---------------
file: debug.php
<?php
include "config.php";
echo $test;


?>

file: config.php

$test="test";


?>


Expected result:
----------------
i am expecting to see 

test

Actual result:
--------------
I see nothing.