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 eq_dvdp c quo q p : c != 0 -> c *: p = quo * q -> q %| p.