Function extern_spec_T__slice_T_last 

pub fn extern_spec_T__slice_T_last<T>(self_: &[T]) -> Option<&T>

extern spec for slice<T>::last

This is not a real function: its only use is for documentation.

terminates

ghost

ensures

result == None ==> self@.len() == 0

ensures

forall<x> result == Some(x) ==> self[self@.len() - 1] == *x