43AJ37IXON6PMMYRZM6OB2MJXPYCNIWW2XBDVNBXIRH5DD7JDTVQC
if !del {
if let Some(intro) = n.introduced_by {
// Check that the edge actually existed at some point.
if !validate_edge(intro, n.from, n.to.start_pos(), n.previous)? {
debug!("edge doesn't exist: {:?}", n);
return Err(crate::Error::InconsistentChange.into());
}
}
}