t: type = {
  operator[]: (this, _) = { }
}

main: () -> int = {
  (x := t()) { x[:() -> _ = 0]; }
  (x := t()) { x[:() -> _ = 0;]; }

  assert(!(:() 0; is int));

  return :i32 = 0;
}

x :== :i32 = 0;
y: i32     = 0;