Description:
------------
PHP 7.3 introduced a minor BC syntax break against 7.2.

Likely this regression was introduced while refactoring to introduce support for flexible heredoc/nowdoc syntax in 7.3.

You can see a failing build here:

https://travis-ci.org/kodus/mail/jobs/485801377

This build succeeds under 7.1 and 7.2, but fails under 7.3.

You can see the parse error affecting 7.3.0 and 7.3.1 here:

https://3v4l.org/1H0l7

(by the way: looks like the documentation page was never updated to reflect changed from the flexible heredoc/nowdoc syntax RFC.)


Test script:
---------------
<?php

$mime_header = <<<MIME
Date: Thu, 15 Sep 2016 17:20:54 +0200
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
MIME;


Expected result:
----------------
Should compile.


Actual result:
--------------
Exits with the following error:

> Parse error: syntax error, unexpected ':' in /in/1H0l7 on line 5