by move/ltnW->.
rewrite leq_eqVlt; case/orP; first by move/eqP->.
by move/modp_small; rewrite rpq => h; move: nq0; rewrite h eqxx.
Qed.

Lemma dvdp_mul2l r p q: r != 0 -> (r * p %| r * q) = (p %| q).