DIP77 - Fix unsafe RC pass by 'ref'

[Walter Bright via Digitalmars-d]

On 4/10/2015 4:49 AM, Michel Fortin wrote:
> ...or maybe not. Let's add another field to Big:
>
>      struct Handle
>      {
>          // shouldn't be able to make copies of this
>          @disable this(this) {}
>      }
>
>      struct Big
>      {
>          RCArray!T array;
>          int[1000] ints;
>          Handle handle;
>      }
>
> Now Big's implicit postblit becomes disabled too (because Handle can't handle
> copying), therefore it is no longer a RCO object and the compiler will no longer
> create temporary copies. Now you've trashed memory-safety.

The copy would be made of array, not Big.