Section S.
Variables x y: Z.
Variables XGe : x >= 0.
Variables YGt : y > 0.
Variables YLt : y < 0.
Goal False.
Proof using - XGe.
lia.
Qed.
Goal False.
Proof using YGt YLt x y.
lia.
Qed.
End S.

(*  Bug 5073 *)
Lemma opp_eq_0_iff a : -a = 0 <-> a = 0.