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;
}