new principle of division between structures and classes

[Weed]

Bill Baxter пишет:

> But since classes can be polymorphic, value copying gets you into
> slicing problems.  That's why value copying is disabled to begin with.
>  So disabling value copies is a good thing.

It is not always a good thing.

I propose to prohibit only the copying by value of the base type to
derivative type

> 
> And that's also the problem with putting scope'd things inside another
> class or an array.  Since they don't have value semantics,

Yes, this is what I mean