libstdc++-v3/testsuite/25_algorithms/is_permutation/lwg3560.cc

   1 // { dg-do run { target c++20 } }
   2
   3 // LWG 3560. ranges::equal and ranges::is_permutation should short-circuit
   4 // for sized_ranges
   5
   6 #include <algorithm>
   7 #include <testsuite_iterators.h>
   8 #include <testsuite_hooks.h>
   9
  10 struct X
  11 {
  12   // Any equality comparison will cause the test to fail.
  13   bool operator==(const X&) const { VERIFY(false); }
  14 };
  15
  16 void
  17 test_std_is_permutation()
  18 {
  19   X vals[3];
  20   __gnu_test::random_access_container<X> r1(vals, vals+3);
  21   __gnu_test::random_access_container<X> r2(vals, vals+2);
  22   VERIFY( ! std::is_permutation(r1.begin(), r1.end(), r2.begin(), r2.end()) );
  23
  24   std::ranges::equal_to pred;
  25   VERIFY( ! std::is_permutation(r1.begin(), r1.end(), r2.begin(), r2.end(),
  26                                 pred) );
  27 }
  28
  29 void
  30 test_std_ranges_is_permutation()
  31 {
  32   X vals[3];
  33   __gnu_test::test_random_access_range<X> r1(vals, vals+3);
  34   __gnu_test::test_random_access_range<X> r2(vals, vals+2);
  35
  36   // Any application of the projection will cause the test to fail.
  37   auto proj = [](const X&) -> const X& { VERIFY(false); };
  38   VERIFY( ! std::ranges::is_permutation(r1.begin(), r1.end(),
  39                                         r2.begin(), r2.end(),
  40                                         {}, proj, proj) );
  41
  42   __gnu_test::test_forward_sized_range<X> r3(vals, vals+3);
  43   __gnu_test::test_forward_sized_range<X> r4(vals, vals+2);
  44   VERIFY( ! std::ranges::is_permutation(r3, r4, {}, proj, proj) );
  45 }
  46
  47 int main()
  48 {
  49   test_std_is_permutation();
  50   test_std_ranges_is_permutation();
  51 }