test/shader_io/interpolate_integers.wgsl

struct Interface {
  [[location(0), interpolate(flat)]] i : i32;
  [[location(1), interpolate(flat)]] u : u32;
  [[location(2), interpolate(flat)]] vi : vec4<i32>;
  [[location(3), interpolate(flat)]] vu : vec4<u32>;
  [[builtin(position)]] pos : vec4<f32>;
};

[[stage(vertex)]]
fn vert_main() -> Interface {
  return Interface();
}

[[stage(fragment)]]
fn frag_main(inputs : Interface) -> [[location(0)]] i32 {
  return inputs.i;
}