Transitive const sucks

[Walter Bright]

Janice Caron wrote:
> Even something as simple as this needs logical const
> 
> class MyMathClass
> {
>     invariant int multiply(int x, int y) /* logically const */
>     {
>         debug logfile.writeLine("multiply.called");
>         return x * y;
>     }
> 
>     debug private Stream logfile;
> }
> 
> You can't tell me that's not a real world need.

You can:

1. make logfile a static member.

2. not use invariant on the multiply. After all, if it isn't actually 
invariant, the invariant declaration wouldn't have any more meaning than 
the comment you put on it.