std::experimental::ranges::tagged<Base,Tags...>::operator=

tagged &operator=(tagged&& that) = default;
 (1)
tagged &operator=(const tagged& that) = default;
 (2)
template <class Other>

    requires Assignable<Base&, Other>
constexpr tagged& operator=(ranges::tagged<Other, Tags...>&& that)

    noexcept(std::is_nothrow_assignable<Base&, Other>::value);
 (3)
template <class Other>

    requires Assignable<Base&, const Other&>

constexpr tagged& operator=(const ranges::tagged<Other, Tags...>& that);
 (4)
template <class U>

    requires Assignable<Base&, U> && !Same<std::decay_t<U>, tagged>

constexpr tagged& operator=(U&& that) noexcept(std::is_nothrow_assignable<Base&, U>::value);
 (5)

Assigns the contents of that to *this.

1-2) tagged has defaulted copy and move assignment operators that invoke the corresponding assignment operator of Base.
3) Converting move assignment from a different tagged specialization with matching tags. Equivalent to static_cast<Base&>(*this) = static_cast<Other&&>(that);.
4) Converting copy assignment from a different tagged specialization with matching tags. Equivalent to static_cast<Base&>(*this) = static_cast<const Other&>(that);.
5) Assigns that to the Base subobject. Equivalent to static_cast<Base&>(*this) = std::forward<U>(that);

Return value

*this.