Fixpoint int_of_one_bits (l: list int) : int :=
match l with
| nil => zero
| a :: b => add (shl one a) (int_of_one_bits b)
end.

(* Specifications: *)
Theorem one_bits_decomp:
forall x, x = int_of_one_bits (one_bits x).
Theorem one_bits_decomp:
forall x, x = int_of_one_bits (one_bits x).