struct FragIn {
  [[location(0)]]
  a : f32;
  [[builtin(sample_mask)]]
  mask : u32;
}

[[stage(fragment)]]
fn main(in : FragIn, [[location(1)]] b : f32) -> FragIn {
  if ((in.mask == 0u)) {
    return in;
  }
  return FragIn(b, 1u);
}