Erroneous `Undefined constant`

[i582]

Code Example

<?php

\define('FREEDESKTOP_XML_URL', 'https://raw.github.com/minad/mimemagic/master/script/freedesktop.org.xml');

$mime_xml = @file_get_contents(FREEDESKTOP_XML_URL);

Actual Behavior

<critical> ERROR   undefined: Undefined constant FREEDESKTOP_XML_URL at ...:5
$mime_xml = @file_get_contents(FREEDESKTOP_XML_URL);
                               ^^^^^^^^^^^^^^^^^^^

Expected Behavior

No error.