bad_converter.nim

type
  CanMove = concept x
    x.move(0.0)

  ICanMove = ref object
    move: proc(tick: float)

  Mover = ref object
    movees: seq[ICanMove]

  Person = ref object

  Animal = ref object

proc ToICanMove[T:CanMove](canMove: T): ICanMove =
  ICanMove(move: proc(tick: float)=
    canMove.move(tick))

proc move(p: Person, tick: float) =
  echo "People can move, tick: " & $tick

template move(a: Animal, tick: float) =
  echo "Animals can move, tick: " & $tick

proc move(m: Mover, tick: float) =
  for movee in m.movees:
    movee.move(tick)

let
  p = new Person
  a = new Animal
  m = Mover(movees: @[])

m.movees.add ToICanMove(p)
m.movees.add ToICanMove(a)

m.move(0.3)
m.move(0.2)