// avoid creation of dummy ref
 FSTClazzInfo.FSTFieldInfo getCachedFI(Class... possibles) {
   if (curDepth >= refs.length) {
     return new FSTClazzInfo.FSTFieldInfo(possibles, null, true);
   } else {
     FSTClazzInfo.FSTFieldInfo inf = refs[curDepth];
     if (inf == null) {
       inf = new FSTClazzInfo.FSTFieldInfo(possibles, null, true);
       refs[curDepth] = inf;
       return inf;
     }
     inf.setPossibleClasses(possibles);
     return inf;
   }
 }