template<typename T, typename U>
void operator==(const Optional<T> &X, const Optional<U> &Y);
+template<typename T>
+bool operator==(const Optional<T> &X, NoneType) {
+ return !X.hasValue();
+}
+
+template<typename T>
+bool operator==(NoneType, const Optional<T> &X) {
+ return X == None;
+}
+
+template<typename T>
+bool operator!=(const Optional<T> &X, NoneType) {
+ return !(X == None);
+}
+
+template<typename T>
+bool operator!=(NoneType, const Optional<T> &X) {
+ return X != None;
+}
/// \brief Poison comparison between two \c Optional objects. Clients needs to
/// explicitly compare the underlying values and account for empty \c Optional
/// objects.