How to turn an inout(Object) into a string

[Meta via Digitalmars-d-learn]

On Sunday, 26 April 2015 at 04:52:36 UTC, Jonathan M Davis wrote:
> It's only undefined if mutation is involved, though I don't 
> know if mutation is involved in this case or not

I was thinking that a class can define an arbitrary toString() 
that modifies it some of its member variables, which definitely 
breaks const-correctness.

class CustomToString
{
     int n;

     override string toString()
     {
         n = 1;

         return "Uh oh";
     }
}

void main()
{
     import std.stdio;

     immutable c = new CustomToString();
     writeln(cast()c);
}