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;
  }
}