message: width() support arrays with zero dimensions
diff: @@ -1089,7 +1089,7 @@ ENOKI_INLINE void eval(const Ts&... values) {
  }
  template <typename T> ENOKI_INLINE size_t width(const T &value) {
  - if constexpr (array_depth_v<T> > 1)
  + if constexpr (array_depth_v<T> > 1 && array_size_v<T> > 0)
  return width(value.derived().entry(0));
  else if constexpr (is_array_v<T>)
  return value.derived().size();
  