public static List buildTypeDefs(List instances) {
    { List typeDefs = List.newList();
      Symbol name = null;

      { Symbol var = null;
        Cons iter000 = instances.theConsList;

        for (;!(iter000 == Stella.NIL); iter000 = iter000.rest) {
          var = ((Symbol)(iter000.value));
          name = ((Symbol)(Logic.$SYMBOL_VARIABLE_HASH_TABLE$.lookup(var)));
          if (!Logic.$DELETED_CASE_VARIABLES$.memberP(name)) {
            typeDefs.push(name);
          }
        }
      }
      return (typeDefs);
    }
  }