AA with complex keytype?

[Manfred Nowak]

Joel Salomon wrote

> Do you know where D insists that “some” ordering be applied to
> a type, and why?

I have given an example that an ordering _operator_ is required by D in 
another branch of this thread:

class C{
  hash_t toHash() { 
    return 0;
  }
}
void main(){
  bool[C] map;
  map[ new C]= true;
  map[ new C]= false;
}

And this branch of the thread discusses Stewarts remark, that an 
ordering operator, which doesn't implement an ordering is senseless in 
his opinion.

-manfred