libstdc++-v3/testsuite/25_algorithms/copy/debug/constexpr_neg.cc

// Copyright (C) 2020-2023 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING3.  If not see
// <http://www.gnu.org/licenses/>.

// { dg-options "-std=gnu++2a" }
// { dg-do compile { target c++2a } }
// { dg-require-debug-mode ""  }

#include <algorithm>
#include <array>

constexpr bool
test1()
{
  constexpr std::array<int, 12> ca0{{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11}};
  std::array<int, 12> ma0{{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}};

  const auto out6 = std::copy(ca0.begin() + 8, ca0.begin(), ma0.begin() + 2);

  return out6 == ma0.begin() + 10;
}

static_assert(test1()); // { dg-error "non-constant condition" }

constexpr bool
test2()
{
  constexpr std::array<int, 12> ca0{{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11}};
  std::array<int, 12> ma0{{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}};

  const auto out6 = std::copy(ca0.begin(), ca0.begin() + 8, ma0.begin() + 10);

  return out6 == ma0.begin() + 18;
}

static_assert(test2()); // { dg-error "is outside the bounds" }

// { dg-prune-output "in 'constexpr' expansion" }
// { dg-prune-output "builtin_unreachable" }
// { dg-prune-output "non-constant condition" }