int main()
{
  auto [min1, max1] = std::minmax(2, 1);  // UB
  auto [min2, max2] = std::minmax({2, 1});
  auto [min3, max3] = std::ranges::minmax(2, 1);  // UB
  auto [min4, max4] = std::ranges::minmax({2, 1});
}

$ clang++ prog.cc -std=c++2a
prog.cc:6:35: warning: temporary whose address is used as value of local variable '[min1, max1]' will be destroyed at the end of the full-expression [-Wdangling]
    6 |   auto [min1, max1] = std::minmax(2, 1);
      |                                   ^
prog.cc:6:38: warning: temporary whose address is used as value of local variable '[min1, max1]' will be destroyed at the end of the full-expression [-Wdangling]
    6 |   auto [min1, max1] = std::minmax(2, 1);
      |                                      ^
prog.cc:8:43: warning: temporary whose address is used as value of local variable '[min3, max3]' will be destroyed at the end of the full-expression [-Wdangling]
    8 |   auto [min3, max3] = std::ranges::minmax(2, 1);
      |                                           ^
prog.cc:8:46: warning: temporary whose address is used as value of local variable '[min3, max3]' will be destroyed at the end of the full-expression [-Wdangling]
    8 |   auto [min3, max3] = std::ranges::minmax(2, 1);
      |                                              ^
4 warnings generated.

$ g++ prog.cc -Wall -Wextra -std=c++2a -O2
prog.cc: In function 'int main()':
prog.cc:6:8: warning: possibly dangling reference to a temporary [-Wdangling-reference]
    6 |   auto [min1, max1] = std::minmax(2, 1);
      |        ^~~~~~~~~~~~
prog.cc:6:34: note: the temporary was destroyed at the end of the full expression 'std::minmax<int>(2, 1)'
    6 |   auto [min1, max1] = std::minmax(2, 1);
      |                       ~~~~~~~~~~~^~~~~~
prog.cc:11:34: warning: '<anonymous>' is used uninitialized [-Wuninitialized]
   11 |   std::cout << "min=" << min1 << " max=" << max1 << std::endl;
      |                                  ^~~~~~~
prog.cc:6:34: note: '<anonymous>' was declared here
    6 |   auto [min1, max1] = std::minmax(2, 1);
      |                       ~~~~~~~~~~~^~~~~~
prog.cc:11:45: warning: '<anonymous>' is used uninitialized [-Wuninitialized]
   11 |   std::cout << "min=" << min1 << " max=" << max1 << std::endl;
      |                                             ^~~~
prog.cc:6:34: note: '<anonymous>' was declared here
    6 |   auto [min1, max1] = std::minmax(2, 1);
      |                       ~~~~~~~~~~~^~~~~~
prog.cc:13:34: warning: '<anonymous>' is used uninitialized [-Wuninitialized]
   13 |   std::cout << "min=" << min3 << " max=" << max3 << std::endl;
      |                                  ^~~~~~~
prog.cc:8:42: note: '<anonymous>' was declared here
    8 |   auto [min3, max3] = std::ranges::minmax(2, 1);
      |                       ~~~~~~~~~~~~~~~~~~~^~~~~~
prog.cc:13:45: warning: '<anonymous>' is used uninitialized [-Wuninitialized]
   13 |   std::cout << "min=" << min3 << " max=" << max3 << std::endl;
      |                                             ^~~~
prog.cc:8:42: note: '<anonymous>' was declared here
    8 |   auto [min3, max3] = std::ranges::minmax(2, 1);
      |                       ~~~~~~~~~~~~~~~~~~~^~~~~~