although IN operator is allowed over the last clustering or partitioning columns, the CQL Query Validator is rejecting queries when they attempt to fetch collection columns in their result set.
It seems a similar bug (
CASSANDRA-5376) was raised some time ago, and a fix (rather mask) was provided to give a better error message to such queries in 1.2.4.
Considering that Cassandra & CQL has evolved a great deal from that period, it now seems possible to provide an actual fix to this problem, i.e. allowing queries to fetch collection columns even when IN operator is used.
please read the following mail thread to understand the context :