Function extern_spec_T_Option_Option_T_flatten 

pub fn extern_spec_T_Option_Option_T_flatten<T>(
    self_: Option<Option<T>>,
) -> Option<T>

extern spec for Option<Option<T>>::flatten

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

terminates

ghost

ensures

self == None ==> result == None

ensures

self == None || self == Some(result)