Constant MAX_IN_LIST_SIZE 

pub const MAX_IN_LIST_SIZE: usize = 20;

Default maximum number of entries in an IN (...) list that will be rewritten into a chain of per-value min/max checks by build_predicate_expression. Callers threading a PredicateRewriter can override this via PredicateRewriter::with_max_in_list_size, and query engines can wire it from the datafusion.execution.parquet.max_in_list_size config option.