I just got it! (invariant/const)

[Janice Caron]

On 09/04/2008, Denton Cockburn <diboss at hotmail.com> wrote:
>  > Of course, the explicit cast necessary to
>  > create an invariant C in the first place is a bit ugly. Maybe we need
>  > "inew" to make new invariant objects?
>
> Couldn't the compiler insert the cast based on the declaration?

No, because objects created by new are not necessarily transitively
unique. For example

    class C
    {
        int * p;

        this()
        {
            p = &someGlobalVariable;
        }
    }

    invariant C c = cast(invariant) new C;
    someGlobalVariable = 1;

Whoops! c just changed!

The explicit cast makes it the programmer's fault, not the compiler's!

Come to think of it, "inew" would suffer the exact same problem, so it
doesn't solve anything. Looks like there's no easy way to make an
invariant class instance.