Function core::slice::sort::insert_tail

unsafe fn insert_tail<T, F>(v: &mut [T], is_less: &mut F)where
    F: FnMut(&T, &T) -> bool,

🔬This is a nightly-only experimental API. (slice_internals)

Inserts v[v.len() - 1] into pre-sorted sequence v[..v.len() - 1] so that whole v[..] becomes sorted.