Instance Inhabitant_share : Inhabitant share := Share.bot. (* TODO: remove this, it's already in sublist.v *)
Instance Inhabitant_mpred : Inhabitant mpred := @FF mpred Nveric. (* TODO: remove this, it's already in sublist.v *)

Lemma mapsto_value_eq: forall sh1 sh2 t p v1 v2, readable_share sh1 -> readable_share sh2 ->
v1 <> Vundef -> v2 <> Vundef -> mapsto sh1 t p v1 * mapsto sh2 t p v2 |-- !!(v1 = v2).