Query to NoWhere

In a three hundred line stored procedure (not bad) one developer noted that the performance issue came down to the corrolated sub-query. Upon inspection, this left-joined monster was not even referenced by any output column, where clause or reference.

What a FIND!

SELECT
a_bunch_of_stuff
FROM #RPT_ORDERS ot
LEFT JOIN (SELECT
Another_long_painful_query
FROM #RPTEXTRA toc
INNER JOIN A_BUNCH_OF_STUFF_TO_MAKE_IT_EVEN_SLOWER tm
WHERE toc.x = 400
GROUP BY toc.y
,tm.starts
) mt ON tmt.ord = mt.ord
AND tmt.starts = mt.starts
ORDER BY more_stuff