Developing a plan for D2.0: Getting everything on the table

[Daniel Keep]

bearophile wrote:
> Andrei Alexandrescu:
>> It could if there was a way to disable the default constructor. Walter 
>> seemed to be interested in the idea.
> 
> (I'm always a little suspicious of library solutions, because they sometimes smell of over-generalization, but sometimes they are a better solution.)
> It's interesting, can you please quickly show me how disabling the default constructor may allow you to implement this solution?

Because:

> struct NonNullable(T)
> {
>   T ptr;
>   alias ptr this;
>
>   this(T ptr)
>   {
>     assert(ptr !is null);
>     this.ptr = ptr;
>   }
>   this(NonNullable!T ptr)
>   {
>     this.ptr = ptr.ptr;
>   }
> }
>
> // Boom!  I just broke your non-nullable type!
> NonNullable!Object o;