When performing a union query on the database and then adding order to the query an error is returned that triggers the incorrect usage of UNION and ORDER BY.

Steps to reproduce the issue

Following the examples in this tutorial:
https://docs.joomla.org/Using_the_union_methods_in_database_queries#union.2C_unionAll_and_unionDistinct

and using this as an example in my module helper file:
$q2
->select('')
->from('#__contact_details')
->where('catid = 26')
->setLimit(5)
;
$q1
->select('')
->from('#__contact_details')
->where('catid = 4')
->setLimit(10)
;
$query
->select('*')
->from('#__contact_details')
->where('1 = 0')
->union($q1)
->union($q2)
->order('name DESC')
;
$test = $db->setQuery($query)->loadObjectList();

Expected result

The expected result is that item are correctly sorted based on the order specified.

Actual result

I receive the error: incorrect usage of UNION and ORDER BY

System information (as much as possible)

Joomla 3.4

Additional comments

Fix can be found in the libraries/joomla/database/query.php

If you change the order that the order and union objects are referenced the query from the example above will work:

eg
if ($this->union)
{
$query .= (string) $this->union;
}

            if ($this->order)
            {
                $query .= (string) $this->order;
            }

Before submitting a pull request I wanted to see if anyone knows if there are any other repercussions in changing the order here.

Thanks