Copy Constructor DIP

[RazvanN]

> But there's a super explicit `@implicit` thing written right 
> there... so should we expect that an *explicit* call to the 
> copy constructor is not allowed? Or maybe it is allowed and 
> `@implicit` is a lie?

The @implicit is there to point out that you cannot call that 
method
explicitly; it gets called for you implicitly when you construct 
an object
as a copy of another object.