let pebble_post ~loc pebble_set aux_var guard =
let v = Cil_const.make_logic_var aux_var.lv_name aux_var.lv_type in
let g = rename_pred aux_var v guard in
let g = Logic_const.pimplies ~loc (mk_sub ~loc pebble_set v, g) in
Logic_const.pforall ~loc ([v], g)