Why doesn't the N3421 provide a noexcept classifier?

Question

In N3421 - Creating functional operators more <> , a new specialization for std function objects:

template <> struct plus<void> {
  template <class T, class U> auto operator()(T&& t, U&& u) const
  -> decltype(std::forward<T>(t) + std::forward<U>(u));
};

instead

template <> struct plus<void> {
  template <class T, class U> auto operator()(T&& t, U&& u) const
  noexcept(noexcept(decltype(std::forward<T>(t) + std::forward<U>(u))
                     (std::move(std::forward<T>(t) + std::forward<U>(u)))))
  -> decltype(std::forward<T>(t) + std::forward<U>(u));
};

• Is there a reason for this?
• Does it make sense to use noexceptin this use case?

Edit: link to a working draft on github .

Edit 2: link to libC ++ plus specialization .

Answer 1

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-, LWG -, noexcept.

Answer 2

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