algorithm/classify_dangling.cpp

This is an example of how the classify() function returns std::ranges::dangling when range is a temporary.

#include <array>
#include <exptl/algorithm>
#include <ranges>
#include <type_traits>
 
// true
static_assert(
  std::is_same_v<std::ranges::range_value_t<decltype(exptl::classify(
                   0, std::array{[](int v) { return v; }}))>,
                 std::ranges::dangling>);