CPP1115 — Copy/move assignment operators should be deleted

ValueBase has only a protected copy/move copy constructor to allow a derived class to make a copy, the assignment operators are deleted, because of this also for a valuebox the assignment operators should be deleted, so the 3rd bullet should be updated from

Protected copy and move assignment operators

to

Private deleted copy and move assignment operators

And in the code example

ColorValue& operator=(const ColorValue&);
ColorValue& operator=(ColorValue&&);

to

ColorValue& operator=(const ColorValue&) = delete;
ColorValue& operator=(ColorValue&&) = delete;

Value box classes shouldn't be assignable

Update to work with ValueBase