Prevent c-treeACE SQL crash with OR-ed subquery

Perceptive Software has reported a series of crashes at customer production sites recently. Upon detailed analysis of several of the mini dump logs obtained from the customers, and through manually forcing the c-treeSQL Server into a similar state as that observed in the mini dump logs, the FairCom R&D team has isolated the crash to the following query:

SELECT DISTINCT TT.* FROM IN_TASK_TEMPLATE TT INNER JOIN IN_USR_TASK_TEMPLATE_PRIV TTP ON TTP.USR_ID IN ( SELECT GROUP_USR_ID FROM IN_USR_GROUP WHERE USR_ID = ? ) OR TTP.USR_ID = ? WHERE TTP.PRIV_ID IN ( 15000 ) AND TT.TASK_TEMPLATE_ID = TTP.TASK_TEMPLATE_ID AND TT.IS_ACTIVE = 1 ORDER BY TT.TASK_TEMPLATE_NAME;

The appropriate internal fix to the c-treeSQL Server has been applied to this line of c-treeACE SQL.