static S migrateClassesInStructureText(S s, O... migrations) {
  L<S> tok = javaTok(s);
  for (int i = 0; i < l(migrations); i += 2) {
    S from = cast migrations[i];
    O to = migrations[i+1];
    
    replace(tok, from, to instanceof S ? (S) to : shortClassName((Class) to));
  }
  ret join(tok);
}