dmd 0.79, WIN98SE

void main(){
  struct data{
    int v1;
  } data d;
  int[data] dict;

  d.v1=1;
  dict[d]=1;
}

The docs say:
| Key types cannot be functions or voids.

Then the example above should work. It compiles but the linker cannot
link:
| Error 42: Symbol Undefined __init_21TypeInfo_S_Dmain4data

So long.