Function extern_spec_T_Option_T_and 

pub fn extern_spec_T_Option_T_and<T, U>(
    self_: Option<T>,
    optb: Option<U>,
) -> Option<U>

extern spec for Option<T>::and

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

terminates

ghost

ensures

self == None ==> result == None && resolve(optb)

ensures

self == None || (result == optb && resolve(self))