Is type iterable trait.

iterable_type_trait.h

namespace detail {

    template<typename T>
    auto is_iterable_impl(int) -> decltype(
        std::begin(std::declval<T&>()) != std::end(std::declval<T&>()),
        ++std::declval<decltype(std::begin(std::declval<T&>()))&>(),
        void(*std::begin(std::declval<T&>())),
        std::true_type{}
    );

    template <typename T>
    std::false_type is_iterable_impl(...);
    
}

///
/// Is the given type iterable?
///
template<typename T>
using is_iterable = decltype(detail::is_iterable_impl<T>(0));