Properly call a generic function in Haxe 3

The following function does nothing useful, but illustrates the syntax I am trying to use.

@:generic public static function newPoint<T: Dynamic>(point: Point<T> = null): Point<T>
{
    if (point == null)
        point = new Point<T>();
    return point;
}

How is T determined/passed? var pt: Point<Int> = newPoint<Int>(); gives me an error, same with var pt: Point<Int> = newPoint();

So what is the correct way of calling such a generic function? Hours of searching for an example have given me nothing - Haxe really is a black box at times.

Here is another example:

@:generic static private function randomElement<T>(array: Array<T>, usedIndices: Map<Int, Int> = null): T
{
  var ix: Int;

  if (usedIndices != null)
  {
    do {
      ix = Math.floor(Math.random() * array.length);
    } while (usedIndices.exists(ix) == true);

    usedIndices.set(ix, 0);
  }
  else {
    ix = Math.floor(Math.random() * array.length);
  }

  return array[ix];
}

Now this works flawlessly for me:

var elems: Array<Int> = [2, 3, 8, 7, 11, 16];
var elem: Int = randomElement(elems);

So it looks like the <T> is determined automatically properly, although I don't know how exactly. It can make sense, but what are the precise rules?