Add Zify UnOp Op_b2n.
#[global]
Instance Op_b2z : UnOp Z.b2z :=
{ TUOp := Z.b2z; TUOpInj _ := eq_refl }.
Add Zify UnOp Op_b2z.

Lemma b2z_spec b : (b = true /\ Z.b2z b = 1) \/ (b = false /\ Z.b2z b = 0).
#[global]
Instance b2zSpec : UnOpSpec Z.b2z :=
{ UPred b r := (b = true /\ r = 1) \/ (b = false /\ r = 0);
USpec := b2z_spec }.