#include <algorithm>
#include <cassert>
#include <forward_list>
#include <vector>

int main()
{
    auto container = std::forward_list{0, 1, 2, 3};
    const auto rg = std::vector{-3, -2, -1};

#if __cpp_lib_containers_ranges
    container.prepend_range(rg);
#else
    container.insert_after(container.before_begin(), rg.cbegin(), rg.cend());
#endif
    assert(std::ranges::equal(container, std::forward_list{-3, -2, -1, 0, 1, 2, 3}));
}