* [PATCH] libstdc++: std::variant with multiple identical types assignment fail to compile [PR91807]
@ 2020-07-01 17:46 Ville Voutilainen
2020-07-01 18:09 ` Ville Voutilainen
0 siblings, 1 reply; 5+ messages in thread
From: Ville Voutilainen @ 2020-07-01 17:46 UTC (permalink / raw)
To: gcc-patches List, libstdc++
[-- Attachment #1: Type: text/plain, Size: 521 bytes --]
Looks like just a small thinko. We construct a temporary and move-construct
from it, but we should construct the temporary with the right index.
OK for trunk and gcc-10 if full tests pass?
2020-07-01 Ville Voutilainen <ville.voutilainen@gmail.com>
PR libstdc++/91807
* include/std/variant
(_Copy_assign_base::operator=(const _Copy_assign_base&):
Do the move-construction from a temporary so that the temporary
is constructed with an explicit index.
* testsuite/20_util/variant/91807.cc: New.
[-- Attachment #2: pr91807.diff --]
[-- Type: text/x-patch, Size: 1830 bytes --]
diff --git a/libstdc++-v3/include/std/variant b/libstdc++-v3/include/std/variant
index c9504914365..eb3d6779205 100644
--- a/libstdc++-v3/include/std/variant
+++ b/libstdc++-v3/include/std/variant
@@ -611,7 +611,8 @@ namespace __variant
this->_M_destructive_copy(__rhs_index, __rhs_mem);
else
__variant_cast<_Types...>(*this)
- = variant<_Types...>(__rhs_mem);
+ = variant<_Types...>(std::in_place_index<__rhs_index>,
+ __rhs_mem);
}
}
else
diff --git a/libstdc++-v3/testsuite/20_util/variant/91807.cc b/libstdc++-v3/testsuite/20_util/variant/91807.cc
new file mode 100644
index 00000000000..ddede7c9b32
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/variant/91807.cc
@@ -0,0 +1,34 @@
+// { dg-do compile { target c++17 } }
+
+// 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/>.
+
+#include <variant>
+
+struct me_data {
+ me_data() = default;
+
+ me_data(const me_data &) {};
+ me_data(me_data &&) noexcept {};
+ me_data& operator=(const me_data &) = default;
+};
+
+int main() {
+ std::variant<me_data, me_data> v1, v2;
+
+ v2 = v1;
+}
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] libstdc++: std::variant with multiple identical types assignment fail to compile [PR91807]
2020-07-01 17:46 [PATCH] libstdc++: std::variant with multiple identical types assignment fail to compile [PR91807] Ville Voutilainen
@ 2020-07-01 18:09 ` Ville Voutilainen
2020-07-01 20:32 ` Ville Voutilainen
0 siblings, 1 reply; 5+ messages in thread
From: Ville Voutilainen @ 2020-07-01 18:09 UTC (permalink / raw)
To: gcc-patches List, libstdc++
On Wed, 1 Jul 2020 at 20:46, Ville Voutilainen
<ville.voutilainen@gmail.com> wrote:
>
> Looks like just a small thinko. We construct a temporary and move-construct
> from it, but we should construct the temporary with the right index.
>
> OK for trunk and gcc-10 if full tests pass?
>
> 2020-07-01 Ville Voutilainen <ville.voutilainen@gmail.com>
>
> PR libstdc++/91807
> * include/std/variant
> (_Copy_assign_base::operator=(const _Copy_assign_base&):
> Do the move-construction from a temporary so that the temporary
> is constructed with an explicit index.
> * testsuite/20_util/variant/91807.cc: New.
And sure, s/move-construction/move-assignment/.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] libstdc++: std::variant with multiple identical types assignment fail to compile [PR91807]
2020-07-01 18:09 ` Ville Voutilainen
@ 2020-07-01 20:32 ` Ville Voutilainen
2020-07-01 20:53 ` Jonathan Wakely
0 siblings, 1 reply; 5+ messages in thread
From: Ville Voutilainen @ 2020-07-01 20:32 UTC (permalink / raw)
To: gcc-patches List, libstdc++
[-- Attachment #1: Type: text/plain, Size: 485 bytes --]
On Wed, 1 Jul 2020 at 21:09, Ville Voutilainen
<ville.voutilainen@gmail.com> wrote:
> And sure, s/move-construction/move-assignment/.
And with dg-options.
2020-07-01 Ville Voutilainen <ville.voutilainen@gmail.com>
PR libstdc++/91807
* include/std/variant
(_Copy_assign_base::operator=(const _Copy_assign_base&):
Do the move-assignment from a temporary so that the temporary
is constructed with an explicit index.
* testsuite/20_util/variant/91807.cc: New.
[-- Attachment #2: pr91807.diff --]
[-- Type: text/x-patch, Size: 1860 bytes --]
diff --git a/libstdc++-v3/include/std/variant b/libstdc++-v3/include/std/variant
index c9504914365..eb3d6779205 100644
--- a/libstdc++-v3/include/std/variant
+++ b/libstdc++-v3/include/std/variant
@@ -611,7 +611,8 @@ namespace __variant
this->_M_destructive_copy(__rhs_index, __rhs_mem);
else
__variant_cast<_Types...>(*this)
- = variant<_Types...>(__rhs_mem);
+ = variant<_Types...>(std::in_place_index<__rhs_index>,
+ __rhs_mem);
}
}
else
diff --git a/libstdc++-v3/testsuite/20_util/variant/91807.cc b/libstdc++-v3/testsuite/20_util/variant/91807.cc
new file mode 100644
index 00000000000..04bb5d7c807
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/variant/91807.cc
@@ -0,0 +1,35 @@
+// { dg-options "-std=gnu++17" }
+// { dg-do compile { target c++17 } }
+
+// 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/>.
+
+#include <variant>
+
+struct me_data {
+ me_data() = default;
+
+ me_data(const me_data &) {};
+ me_data(me_data &&) noexcept {};
+ me_data& operator=(const me_data &) = default;
+};
+
+int main() {
+ std::variant<me_data, me_data> v1, v2;
+
+ v2 = v1;
+}
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] libstdc++: std::variant with multiple identical types assignment fail to compile [PR91807]
2020-07-01 20:32 ` Ville Voutilainen
@ 2020-07-01 20:53 ` Jonathan Wakely
2020-07-01 21:00 ` Ville Voutilainen
0 siblings, 1 reply; 5+ messages in thread
From: Jonathan Wakely @ 2020-07-01 20:53 UTC (permalink / raw)
To: Ville Voutilainen; +Cc: gcc-patches List, libstdc++
On 01/07/20 23:32 +0300, Ville Voutilainen via Libstdc++ wrote:
>On Wed, 1 Jul 2020 at 21:09, Ville Voutilainen
><ville.voutilainen@gmail.com> wrote:
>> And sure, s/move-construction/move-assignment/.
>
>And with dg-options.
OK for master and gcc-10, thanks.
Does it apply cleanly to gcc-9 too?
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] libstdc++: std::variant with multiple identical types assignment fail to compile [PR91807]
2020-07-01 20:53 ` Jonathan Wakely
@ 2020-07-01 21:00 ` Ville Voutilainen
0 siblings, 0 replies; 5+ messages in thread
From: Ville Voutilainen @ 2020-07-01 21:00 UTC (permalink / raw)
To: Jonathan Wakely; +Cc: gcc-patches List, libstdc++
On Wed, 1 Jul 2020 at 23:53, Jonathan Wakely <jwakely@redhat.com> wrote:
>
> On 01/07/20 23:32 +0300, Ville Voutilainen via Libstdc++ wrote:
> >On Wed, 1 Jul 2020 at 21:09, Ville Voutilainen
> ><ville.voutilainen@gmail.com> wrote:
> >> And sure, s/move-construction/move-assignment/.
> >
> >And with dg-options.
>
> OK for master and gcc-10, thanks.
>
> Does it apply cleanly to gcc-9 too?
Yes. I managed to misremember where the new variant implementation
landed and misread the
bug title/version, so backporting there, too.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2020-07-01 21:01 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-07-01 17:46 [PATCH] libstdc++: std::variant with multiple identical types assignment fail to compile [PR91807] Ville Voutilainen
2020-07-01 18:09 ` Ville Voutilainen
2020-07-01 20:32 ` Ville Voutilainen
2020-07-01 20:53 ` Jonathan Wakely
2020-07-01 21:00 ` Ville Voutilainen
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).