libcxx/test/std/utilities/function.objects/comparisons/constexpr_init.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // UNSUPPORTED: c++03, c++11
  10
  11 // <functional>
  12
  13 // equal_to, not_equal_to, less, et al.
  14
  15 // Test that these types can be constructed w/o an initializer in a constexpr
  16 // context. This is specifically testing gcc.gnu.org/PR83921
  17
  18
  19 #include <functional>
  20 #include "test_macros.h"
  21
  22 template <class T>
  23 constexpr bool test_constexpr_context() {
  24   std::equal_to<T> eq;
  25   ((void)eq);
  26   std::not_equal_to<T> neq;
  27   ((void)neq);
  28   std::less<T> l;
  29   ((void)l);
  30   std::less_equal<T> le;
  31   ((void)le);
  32   std::greater<T> g;
  33   ((void)g);
  34   std::greater_equal<T> ge;
  35   ((void)ge);
  36   return true;
  37 }
  38
  39 static_assert(test_constexpr_context<int>(), "");
  40 static_assert(test_constexpr_context<void>(), "");
  41
  42
  43 int main(int, char**) {
  44
  45
  46   return 0;
  47 }