[gcc r10-9607] libstdc++: Add workaround for weird std::tuple error [PR 96592]
Jonathan Wakely
redi@gcc.gnu.org
Mon Mar 29 20:04:33 GMT 2021
https://gcc.gnu.org/g:202e96058031b8ac2edc8fdab2faab06b988a253
commit r10-9607-g202e96058031b8ac2edc8fdab2faab06b988a253
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Thu Sep 3 16:26:16 2020 +0100
libstdc++: Add workaround for weird std::tuple error [PR 96592]
This "fix" makes no sense, but it avoids an error from G++ about
std::is_constructible being incomplete. The real problem is elsewhere,
but this "fixes" the regression for now.
libstdc++-v3/ChangeLog:
PR libstdc++/96592
* include/std/tuple (_TupleConstraints<true, T...>): Use
alternative is_constructible instead of std::is_constructible.
* testsuite/20_util/tuple/cons/96592.cc: New test.
(cherry picked from commit 032a4b42cc5f2105f622690ce2552f1c30e1d227)
Diff:
---
libstdc++-v3/include/std/tuple | 4 ++
libstdc++-v3/testsuite/20_util/tuple/cons/96592.cc | 58 ++++++++++++++++++++++
2 files changed, 62 insertions(+)
diff --git a/libstdc++-v3/include/std/tuple b/libstdc++-v3/include/std/tuple
index 94b9e0335b1..99121532101 100644
--- a/libstdc++-v3/include/std/tuple
+++ b/libstdc++-v3/include/std/tuple
@@ -460,6 +460,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
template<bool, typename... _Types>
struct _TupleConstraints
{
+ template<typename _Tp, typename _Up> // Workaround for PR 96592
+ using is_constructible
+ = __bool_constant<__is_constructible(_Tp, _Up)>;
+
// Constraint for a non-explicit constructor.
// True iff each Ti in _Types... can be constructed from Ui in _UTypes...
// and every Ui is implicitly convertible to Ti.
diff --git a/libstdc++-v3/testsuite/20_util/tuple/cons/96592.cc b/libstdc++-v3/testsuite/20_util/tuple/cons/96592.cc
new file mode 100644
index 00000000000..326ab0ef2a6
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/tuple/cons/96592.cc
@@ -0,0 +1,58 @@
+// 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-do compile { target c++11 } }
+
+#include <tuple>
+
+// PR 96592 comment 0
+
+template <typename SessionT>
+struct SomeQuery {
+ SessionT& session_;
+ SomeQuery(SessionT& session) : session_(session) {}
+};
+
+template <typename SessionT>
+struct Handler {
+ std::tuple<SomeQuery<SessionT>> queries_;
+ Handler(SessionT& session) : queries_(session) {}
+};
+
+struct Session {
+ Handler<Session> handler_;
+ Session() : handler_{*this} {}
+};
+
+Session session;
+
+// PR 96592 comment 1
+template <typename T>
+class DependsOnT
+{
+public:
+ DependsOnT(T&) {}
+};
+
+class Test
+{
+public:
+ Test() : test_{*this} {}
+
+private:
+ std::tuple<DependsOnT<Test>> test_;
+};
More information about the Libstdc++-cvs
mailing list