message: Small fix to loop
diff: @@ -83,7 +83,7 @@ struct Loop<Mask, enable_if_jit_array_t<Mask>> {
  if constexpr (is_array_v<Value>) {
  if constexpr (array_depth_v<Value> == 1) {
  if constexpr (is_diff_array_v<Value>) {
  - if (has_grad(value))
  + if (grad_enabled(value))
  jit_raise("enoki::Loop::put(): loop variable is "
  "attached to the AD graph!");
  put(value.detach_());
  