faulty cloning in nim

ball.nim

type
  # ...
  Vector*[T] = object
    x*, y*: T

  Animatable* = object of RootObj

  Ball* = object of Animatable
    pos*: Vector[float]
    

method clone*(anim: Animatable): ref Animatable  {.base.} =
  raise
  
method badclone*(anim: Animatable): ref Animatable  {.base.} =
  raise
  
# this makes a bad (incomplete) copy
method badclone*(ball: Ball): ref Animatable =
  result.new
  result[].deepCopy(ball)


# This works 
method clone*(ball: Ball): ref Animatable =
  var ball2 = new Ball
  ball2[].deepCopy(ball)
  result = ball2
  
var
  ball = Ball(pos: Vector[float](x: 111, y: 999))
  goodball = ball.clone
  badball = ball.badclone

echo repr ball
echo repr goodball
echo repr badball

discard """output:

nim c -r --verbosity\:0 --hint\[Processing\]\:off --excessiveStackTrace\:on /home/nick/i/gitworking/noofac/nim-bounce/scratch.nim
[pos = [x = 111.0,
y = 999.0]]

ref 0x7f13067e8048 --> [pos = [x = 111.0,
y = 999.0]]

ref 0x7f13067e9048 --> [pos = [x = 1.531603502107864e-322,
y = 0.0]]

"""