program T {
  entry {
    let xs = new []int
    print(len(xs))       # 0
    for i in 0 .. 20 { push(xs, i * i) }
    print(len(xs))       # 20
    print(xs[19])        # 361
    xs[3] = 777
    print(xs[3])         # 777
  }
}