Definition Mint_LmodMixin :=
@LmodMixin _ [zmodType of M] (fun n x => x *~ n)
mulrzA_C mulr1z mulrzDr mulrzDl.
Canonical Mint_LmodType := LmodType int M^z Mint_LmodMixin.

Lemma mulz2 n : n * 2%:Z = n + n. Proof. by rewrite -mulrzz. Qed.