string types: const(char)[] and cstring

[Reiner Pope]

Walter Bright wrote:
> Under the new const/invariant/final regime, what are strings going to be 
> ? Experience with other languages suggest that strings should be 
> immutable. To express an array of const chars, one would write:
> 
>     const(char)[]
> 
...
> String literals, on the other hand, will be invariant (which means they 
> can be stuffed into read-only memory). So,
>     typeof("abc")
> will be:
>     invariant(char)[3]

The thing I don't get about this syntax is what happens when you take 
off the [].

1.   invariant(char) c = 'b'; // c is 'b' now, and will never change.
2.   final(char) d = 'b';     // but calling it final means the same...
3.   const(char) e = 'b';     // ummm... what?

It seems like const(char) is a constant char -- one that can't change. 
Does that make final obsolete?

Also, I can't see any difference between const(char) and 
invariant(char), since neither can ever be rebound. In that case, if I 
assume that they are identical types, how can an array of const(char) be 
different from an array of invariant(char)?

-- Reiner