Why can't we define re-assignable const reference variable?

[Frits van Bommel]

Janice Caron wrote:
>     char[] s;
>     s.length = 5;
>     /* blah */
>     s.length = 25;
>     /* blah */
>     s.length = 10;
> 
> etc. In this case, the buffer will be reallocated somewhere else, and
> the original contents copied so you don't lose anything. It's exactly
> like calling realloc() in C or C++.

Well, there's one difference between what happens there and realloc(); 
the latter deallocates the original while D leaves the original in place 
in case there are other references to it. (This is more workable in D 
than C/C++ though, since if there aren't the GC will clean it up)