test/tint/bug/tint/2121.wgsl

struct VSOut {
  @builtin(position) pos: vec4<f32>,
};

fn foo(out: ptr<function, VSOut>) {
  var pos = vec4f(1, 2, 3, 4);
  (*out).pos = pos;
}

@vertex fn main() -> VSOut {
  var out: VSOut;
  foo(&out);
  return out;
}