File "pr4824a_bad.ml", line 10, characters 2-45:
10 |   struct class c x = object val x = x end end
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Error: Signature mismatch:
       ...
       Class declarations do not match:
         class c : 'a -> object val x : 'a end
       does not match
         class c : 'a -> object val x : 'b end
       The instance variable x has type 'a but is expected to have type 'b