Function cmp_version_precedence 

pub(crate) fn cmp_version_precedence(
    left: Option<&Version>,
    right: Option<&Version>,
) -> Ordering

Compare optional package versions by SemVer precedence, i.e. ignoring build metadata as the spec requires (1.0.0+a and 1.0.0+b rank equally). None orders below any Some, matching Option’s own ordering.