Check if arbitrary type can use for-each loop by using C++ SFINAE

iterable.h

#include <iterator>
#include <type_traits>

template<typename T, typename = void>
struct is_iterable : std::false_type {};

template<typename T>
struct is_iterable<T, std::void_t<decltype(*std::begin(std::declval<T&>()) != *std::end(std::declval<T&>())),
                                  decltype(++std::declval<decltype(std::begin(std::declval<T&>()))&>())>> : std::true_type {};

template<typename T>
inline constexpr bool is_iterable_v = is_iterable<T>::value;

/**
 * @tparam I iterable
 */
template<typename I>
using iterator_type = decltype(*std::begin(std::declval<I&>()));

/**
 * Check if `I` is Iterable<T>.
 * @tparam I iterable
 * @tparam T iterator type
 */
template<typename I, typename T>
concept Iterable1D = is_iterable_v<I&> && std::is_convertible_v<iterator_type<I>, T>;

/**
 * Check if `I` is Iterable<Iterable<T>>.
 * @tparam I iterable
 * @tparam T iterator type
 */
template<typename I, typename T>
concept Iterable2D = is_iterable_v<I> && Iterable1D<iterator_type<I>, T>;