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. Tested powerpc64le-linux. Committed to trunk. This needs to go on the gcc-10 branch too.
commit 032a4b42cc5f2105f622690ce2552f1c30e1d227 Author: Jonathan Wakely <jwak...@redhat.com> Date: Thu Sep 3 16:26:16 2020 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. diff --git a/libstdc++-v3/include/std/tuple b/libstdc++-v3/include/std/tuple index 1c22d4db788..06f56337ce4 100644 --- a/libstdc++-v3/include/std/tuple +++ b/libstdc++-v3/include/std/tuple @@ -539,6 +539,10 @@ _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_; +};