foreach, tupleof

[Ellery Newcomer]

Hello.

In D1, this code fails:
void foo(S)(ref S s){
  foreach(ref k; s.tupleof){
    k = 1;
  }
}

struct K{
  int g;
}

void main(){
  K k;
  foo(k);
  assert(k.g == 1);
}


test.d(5): Error: no storage class for value k

(referring to 'k = 1;')

Is this an expected error, and is there a good way to get the semantics 
to actually work?