dawn-cmake/test/shader_io/vertex_input_builtins_struct.wgsl

struct VertexInputs {
  [[builtin(vertex_index)]] vertex_index : u32;
  [[builtin(instance_index)]] instance_index : u32;
};

[[stage(vertex)]]
fn main(inputs : VertexInputs) -> [[builtin(position)]] vec4<f32> {
  let foo : u32 = inputs.vertex_index + inputs.instance_index;
  return vec4<f32>();
}