libstdc++-v3/testsuite/23_containers/span/explicit.cc

   1 // Copyright (C) 2020-2023 Free Software Foundation, Inc.
   2 //
   3 // This file is part of the GNU ISO C++ Library.  This library is free
   4 // software; you can redistribute it and/or modify it under the
   5 // terms of the GNU General Public License as published by the
   6 // Free Software Foundation; either version 3, or (at your option)
   7 // any later version.
   8
   9 // This library is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13
  14 // You should have received a copy of the GNU General Public License along
  15 // with this library; see the file COPYING3.  If not see
  16 // <http://www.gnu.org/licenses/>.
  17
  18 // { dg-options "-std=gnu++2a" }
  19 // { dg-do compile { target c++2a } }
  20
  21 #include <span>
  22
  23 struct Range
  24 {
  25   int* begin();
  26   int* end();
  27   unsigned size() const;
  28 } r;
  29
  30 auto first = std::begin(r), last = std::end(r);
  31
  32 // span(It, size_type)
  33 std::span<int> s1 = {first, 2};
  34 std::span<int, 2> s2 = {first, 2}; // { dg-error "explicit constructor" }
  35
  36 // span(It, End)
  37 std::span<int> s3 = {first, last};
  38 std::span<int, 2> s4 = {first, last}; // { dg-error "explicit constructor" }
  39
  40 // span(R&&)
  41 std::span<int> s5 = r;
  42 std::span<int, 2> s6 = r; // { dg-error "conversion from" }
  43
  44 // span(const span<OtherElement, OtherExtent>&)
  45 std::span<const int> s7 = s5;
  46 std::span<const int> s8 = s6;
  47 std::span<const int, 1> s9 = s5.first(1);  // { dg-error "conversion from" }
  48 std::span<const int, 1> s10 = s7.first(1); // { dg-error "conversion from" }