CppUG_staticAssert.h

#include <type_traits>

template <class T>
void swap(T& a, T& b) {
    static_assert(std::is_copy_constructible<T>::value,
                  "Swap requires copying");
    static_assert(std::is_nothrow_move_constructible<T>::value
               && std::is_nothrow_move_assignable<T>::value,
                  "Swap may throw");
    auto c = b;
    b = a;
    a = c;
}