unfold G2_3, G2_4.
inline_first.
comp_skip.
inline_first.
eapply comp_spec_eq_impl_eq.
comp_skip.
eapply A_randomFunc_F_spec.
simpl in *.
comp_simp.
simpl.
eapply comp_spec_ret; intuition.
Qed.

(* Specifications: *)
Theorem G2_3_4_eq_until_bad :
forall x,
evalDist G2_3 (x, false) == evalDist G2_4 (x, false).
Theorem G2_3_4_eq_until_bad :
forall x,
evalDist G2_3 (x, false) == evalDist G2_4 (x, false).