Invariants broken with out cast!!!

[Denton Cockburn]

On Thu, 06 Dec 2007 20:43:12 -0800, Robert DaSilva wrote:

> An invariant(int) can be assigned to an invariant(int)*, this wasn't
> possible in 2.007. Just compile the attach test case. import std.stdio;
> 
> void main()
> {
>     invariant(int) a;
>     invariant(int)* b = &a; // error in 2.007, ok in 2.008 writeln(*b);
>     a = 1;
> //    *b = 2; // error
>     writeln(*b);
> }

Then again, I'd expect *b to be mutable if a is mutable.
Someone care to explain what the correct behaviour should be and why?