Function absence_refused 

pub fn absence_refused(
    new_set: &[Package],
    context: &[Package],
    package: &str,
    container: &str,
    member: &str,
) -> bool

Whether a reader built against new_set refuses a payload in which the field member of struct container, in package package, is absent — the rule that makes an appended field breaking for its type (driftsys/ridl#598). context holds packages that references resolve against without being compared, such as ridl.std. false when container is not a struct of that package. The ridl check desk check reads it to say so in its RIDL-407 message for an append that also sits beside a moved sibling.