Function extern_spec_T_Option_T_as_mut 

pub fn extern_spec_T_Option_T_as_mut<T>(self_: &mut Option<T>) -> Option<&mut T>

extern spec for Option<T>::as_mut

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

terminates

ghost

ensures

*self == None ==> result == None && ^self == None

ensures

*self == None
|| exists<r: &mut T> result == Some(r) && *self == Some(*r) && ^self == Some(^r)