Function missing_policy_columns 

pub fn missing_policy_columns(
    allow: &[ReadPolicy],
    deny: &[ReadPolicy],
    present: &[&str],
) -> Vec<&'static str>

The columns of the policy’s own model that allow / deny read and present does not hold. A relation predicate counts its local join column only: its nested expression runs in SQL against the related table, where every column is there.