(* Baseline: mutable record fields via r.f <- v *)
type counter = { mutable count : int; mutable last : int } ;;

let bump c =
  c.count <- c.count + 1 ;
  c.last <- c.count
;;

let c = { count = 0; last = 0 } ;;
bump c ;;
bump c ;;
bump c ;;
bump c ;;
bump c ;;
c.count + c.last