[[block]]
struct S {
  v : vec3<f32>;
};

[[group(0), binding(0)]] var<storage, read_write> U : S;

fn f() {
  U.v = vec3<f32>(1.0, 2.0, 3.0);
  U.v.x = 1.0;
  U.v.y = 2.0;
  U.v.z = 3.0;
}