19 General utilities library [utilities]

19.8 Storage for any type [any]

19.8.3 Class any [any.class]

19.8.3.2 Assignment [any.assign]

any& operator=(const any& rhs);
Effects: As if by any(rhs).swap(*this).
No effects if an exception is thrown.
Returns: *this.
Throws: Any exceptions arising from the copy constructor for the contained value.
any& operator=(any&& rhs) noexcept;
Effects: As if by any(std::move(rhs)).swap(*this).
Returns: *this.
Ensures: The state of *this is equivalent to the original state of rhs and rhs is left in a valid but otherwise unspecified state.
template<class T> any& operator=(T&& rhs);
Let VT be decay_­t<T>.
Requires: VT shall satisfy the Cpp17CopyConstructible requirements.
Effects: Constructs an object tmp of type any that contains an object of type VT direct-initialized with std::forward<T>(rhs), and tmp.swap(*this).
No effects if an exception is thrown.
Returns: *this.
Remarks: This operator shall not participate in overload resolution unless VT is not the same type as any and is_­copy_­constructible_­v<VT> is true.
Throws: Any exception thrown by the selected constructor of VT.