The standard CQL list type doesn't allow for nulls inside the collection. However lists of IN values are the exception where bind nullsare allowed, for example in restrictions like: p IN (1, 2, null) To be able to use list_prepare_expression with lists of IN values a flag is added to specify whether nulls should be allowed. Signed-off-by: cvybhu <jan.ciolek@scylladb.com>