Function extern_spec_T_Option_T_map_or_else 

pub fn extern_spec_T_Option_T_map_or_else<T, U, D: FnOnce() -> U, F: FnOnce(T) -> U>(
    self_: Option<T>,
    default: D,
    f: F,
) -> U

extern spec for Option<T>::map_or_else

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

requires

match self {
    None => default.precondition(()),
    Some(t) => f.precondition((t,)),
}

ensures

match self {
    None => default.postcondition_once((), result),
    Some(t) => f.postcondition_once((t,), result),
}