dawn-cmake/test/shader_io/fragment_input_builtins_struct.wgsl

struct FragmentInputs {
  [[builtin(position)]] position : vec4<f32>;
  [[builtin(front_facing)]] front_facing : bool;
  [[builtin(sample_index)]] sample_index : u32;
  [[builtin(sample_mask)]] sample_mask : u32;
};

[[stage(fragment)]]
fn main(inputs : FragmentInputs) {
  if (inputs.front_facing) {
    let foo : vec4<f32> = inputs.position;
    let bar : u32 = inputs.sample_index + inputs.sample_mask;
  }
}