OpenE2K/gcc
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

libstdc++: Avoid CTAD for std::ranges::join_view [LWG 3474]

Browse Source 
In commit ef275d1f20 I implemented the
wrong resolution of LWG 3474. This removes the deduction guide and
alters the views::join factory to create the right type explicitly.

libstdc++-v3/ChangeLog:

	* include/std/ranges (join_view): Remove deduction guide.
	(views::join): Add explicit template argument list to prevent
	deducing the wrong type.
	* testsuite/std/ranges/adaptors/join.cc: Move test for LWG 3474
	here, from ...
	* testsuite/std/ranges/adaptors/join_lwg3474.cc: Removed.
This commit is contained in:
Jonathan Wakely 2020-10-06 09:41:16 +01:00
parent bf510679bb
commit 9065c4adab
3 changed files with 19 additions and 43 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
libstdc++-v3/include/std/ranges
View File

@ -2369,17 +2369,14 @@ namespace views
template<typename _Range>
explicit join_view(_Range&&) -> join_view<views::all_t<_Range>>;
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 3474. Nesting join_views is broken because of CTAD
template<typename _View>
explicit join_view(join_view<_View>) -> join_view<join_view<_View>>;
namespace views
{
inline constexpr __adaptor::_RangeAdaptorClosure join
= [] <viewable_range _Range> (_Range&& __r)
{
return join_view{std::forward<_Range>(__r)};
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 3474. Nesting join_views is broken because of CTAD
return join_view<views::all_t<_Range>>{std::forward<_Range>(__r)};
};
} // namespace views

16
libstdc++-v3/testsuite/std/ranges/adaptors/join.cc
View File

@ -123,6 +123,21 @@ test06()
b = ranges::end(v);
}
void
test07()
{
// LWG 3474. Nesting join_views is broken because of CTAD
std::vector<std::vector<std::vector<int>>> nested_vectors = {
{{1, 2, 3}, {4, 5}, {6}},
{{7}, {8, 9}, {10, 11, 12}},
{{13}}
};
auto joined = nested_vectors | std::views::join | std::views::join;
using V = decltype(joined);
static_assert( std::same_as<std::ranges::range_value_t<V>, int> );
}
int
main()
{
@ -132,4 +147,5 @@ main()
test04();
test05();
test06();
test07();
}

37
libstdc++-v3/testsuite/std/ranges/adaptors/join_lwg3474.cc
View File

@ -1,37 +0,0 @@
// Copyright (C) 2020 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 } }
#include <ranges>
#include <vector>
void
test01()
{
// LWG 3474. Nesting join_views is broken because of CTAD
std::vector<std::vector<std::vector<int>>> nested_vectors = {
{{1, 2, 3}, {4, 5}, {6}},
{{7}, {8, 9}, {10, 11, 12}},
{{13}}
};
auto joined = nested_vectors | std::views::join | std::views::join;
using V = decltype(joined);
static_assert( std::same_as<std::ranges::range_value_t<V>, int> );
}