From: Ville Voutilainen Date: Wed, 30 Nov 2016 09:59:50 +0000 (+0200) Subject: Implement LWG 2534, Constrain rvalue stream operators. X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=a7da4881303a7bc9a59014f0d03cd946a9cdecec;p=gcc.git Implement LWG 2534, Constrain rvalue stream operators. * include/std/istream (__is_convertible_to_basic_istream): New. (__is_extractable): Likewise. (operator>>(basic_istream<_CharT, _Traits>&&, _Tp&&)): Turn the stream parameter into a template parameter and constrain. * include/std/ostream (__is_convertible_to_basic_ostream): New. (__is_insertable): Likewise. (operator<<(basic_ostream<_CharT, _Traits>&&, const _Tp&)): Turn the stream parameter into a template parameter and constrain. * testsuite/27_io/basic_istream/extractors_other/char/4.cc: New. * testsuite/27_io/basic_istream/extractors_other/wchar_t/4.cc: Likewise. * testsuite/27_io/basic_ostream/inserters_other/char/6.cc: Likewise. * testsuite/27_io/basic_ostream/inserters_other/wchar_t/6.cc: Likewise. From-SVN: r243006 --- diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog index 234516857df..fd26b1cfdf0 100644 --- a/libstdc++-v3/ChangeLog +++ b/libstdc++-v3/ChangeLog @@ -1,3 +1,22 @@ +2016-11-30 Ville Voutilainen + + Implement LWG 2534, Constrain rvalue stream operators. + * include/std/istream (__is_convertible_to_basic_istream): New. + (__is_extractable): Likewise. + (operator>>(basic_istream<_CharT, _Traits>&&, _Tp&&)): + Turn the stream parameter into a template parameter + and constrain. + * include/std/ostream (__is_convertible_to_basic_ostream): New. + (__is_insertable): Likewise. + (operator<<(basic_ostream<_CharT, _Traits>&&, const _Tp&)): + Turn the stream parameter into a template parameter + and constrain. + * testsuite/27_io/basic_istream/extractors_other/char/4.cc: New. + * testsuite/27_io/basic_istream/extractors_other/wchar_t/4.cc: + Likewise. + * testsuite/27_io/basic_ostream/inserters_other/char/6.cc: Likewise. + * testsuite/27_io/basic_ostream/inserters_other/wchar_t/6.cc: Likewise. + 2016-11-30 Christophe Lyon * testsuite/experimental/type_erased_allocator/2.cc: Add diff --git a/libstdc++-v3/include/std/istream b/libstdc++-v3/include/std/istream index c8a2e08e9f9..4f0e940b2aa 100644 --- a/libstdc++-v3/include/std/istream +++ b/libstdc++-v3/include/std/istream @@ -908,6 +908,28 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION ws(basic_istream<_CharT, _Traits>& __is); #if __cplusplus >= 201103L + + template + struct __is_convertible_to_basic_istream + { + template + static true_type __check(basic_istream<_Ch, _Up>*); + + static false_type __check(void*); + public: + using type = decltype(__check(declval<_Tp*>())); + constexpr static bool value = type::value; + }; + + template + struct __is_extractable : false_type {}; + + template + struct __is_extractable<_Istream, _Tp, + __void_t() + >> declval<_Tp>())>> + : true_type {}; + // [27.7.1.6] Rvalue stream extraction // _GLIBCXX_RESOLVE_LIB_DEFECTS // 2328. Rvalue stream extraction should use perfect forwarding @@ -921,9 +943,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION * rvalue streams since they won't bind to the extractor functions * that take an lvalue reference. */ - template - inline basic_istream<_CharT, _Traits>& - operator>>(basic_istream<_CharT, _Traits>&& __is, _Tp&& __x) + template + inline + typename enable_if<__and_<__not_>, + __is_convertible_to_basic_istream< + typename remove_reference<_Istream>::type>, + __is_extractable<_Istream&, _Tp&&>>::value, + _Istream&>::type + operator>>(_Istream&& __is, _Tp&& __x) { __is >> std::forward<_Tp>(__x); return __is; diff --git a/libstdc++-v3/include/std/ostream b/libstdc++-v3/include/std/ostream index 0bf53f00b03..a1fe892ccdb 100644 --- a/libstdc++-v3/include/std/ostream +++ b/libstdc++-v3/include/std/ostream @@ -613,6 +613,27 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION { return __os.flush(); } #if __cplusplus >= 201103L + template + struct __is_convertible_to_basic_ostream + { + template + static true_type __check(basic_ostream<_Ch, _Up>*); + + static false_type __check(void*); + public: + using type = decltype(__check(declval<_Tp*>())); + constexpr static bool value = type::value; + }; + + template + struct __is_insertable : false_type {}; + + template + struct __is_insertable<_Ostream, _Tp, + __void_t() + << declval())>> + : true_type {}; + /** * @brief Generic inserter for rvalue stream * @param __os An input stream. @@ -623,9 +644,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION * rvalue streams since they won't bind to the inserter functions * that take an lvalue reference. */ - template - inline basic_ostream<_CharT, _Traits>& - operator<<(basic_ostream<_CharT, _Traits>&& __os, const _Tp& __x) + template + inline + typename enable_if<__and_<__not_>, + __is_convertible_to_basic_ostream< + typename remove_reference<_Ostream>::type>, + __is_insertable<_Ostream&, const _Tp&>>::value, + _Ostream&>::type + //basic_ostream<_CharT, _Traits>& + operator<<(_Ostream&& __os, const _Tp& __x) { __os << __x; return __os; diff --git a/libstdc++-v3/testsuite/27_io/basic_istream/extractors_other/char/4.cc b/libstdc++-v3/testsuite/27_io/basic_istream/extractors_other/char/4.cc new file mode 100644 index 00000000000..0922b0b643c --- /dev/null +++ b/libstdc++-v3/testsuite/27_io/basic_istream/extractors_other/char/4.cc @@ -0,0 +1,96 @@ +// { dg-do run { target c++11 } } + +// Copyright (C) 2016 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 +// . + +// 27.6.2.5.3 basic_ostream manipulator inserters + +#include + +struct X {}; +std::istream& operator>>(std::istream&, X&) = delete; + +struct Y {}; +std::istream& operator>>(std::istream& is, Y&) {return is;} +std::istream& operator>>(std::istream& is, Y&&) {return is;} + +struct Z{}; + +template +auto f(T&&) -> decltype(void(std::declval() + >> std::declval()), + std::true_type()); + +std::false_type f(...); + +template +auto g(T&&) -> decltype(void(std::declval() + >> std::declval()), + std::true_type()); + +std::false_type g(...); + +void test01() +{ + Y y; + std::istringstream is; + is >> y; + is >> Y(); + std::istringstream() >> y; + std::istringstream() >> Y(); + static_assert(!std::__is_extractable::value, ""); + static_assert(!std::__is_extractable::value, ""); + static_assert(!std::__is_extractable::value, ""); + static_assert(!std::__is_extractable::value, ""); + static_assert(std::__is_extractable::value, ""); + static_assert(std::__is_extractable::value, ""); + static_assert(std::__is_extractable::value, ""); + static_assert(std::__is_extractable::value, ""); + static_assert(!std::__is_extractable::value, ""); + static_assert(!std::__is_extractable::value, ""); + static_assert(!std::__is_extractable::value, ""); + static_assert(!std::__is_extractable::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); + static_assert(std::is_same())), + std::true_type>::value, ""); + static_assert(std::is_same())), + std::true_type>::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); + static_assert(std::is_same())), + std::true_type>::value, ""); + static_assert(std::is_same())), + std::true_type>::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); +} + +int main() +{ + test01(); +} diff --git a/libstdc++-v3/testsuite/27_io/basic_istream/extractors_other/wchar_t/4.cc b/libstdc++-v3/testsuite/27_io/basic_istream/extractors_other/wchar_t/4.cc new file mode 100644 index 00000000000..87c4ce420de --- /dev/null +++ b/libstdc++-v3/testsuite/27_io/basic_istream/extractors_other/wchar_t/4.cc @@ -0,0 +1,96 @@ +// { dg-do run { target c++11 } } + +// Copyright (C) 2016 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 +// . + +// 27.6.2.5.3 basic_ostream manipulator inserters + +#include + +struct X {}; +std::wistream& operator>>(std::wistream&, X&) = delete; + +struct Y {}; +std::wistream& operator>>(std::wistream& is, Y&) {return is;} +std::wistream& operator>>(std::wistream& is, Y&&) {return is;} + +struct Z{}; + +template +auto f(T&&) -> decltype(void(std::declval() + >> std::declval()), + std::true_type()); + +std::false_type f(...); + +template +auto g(T&&) -> decltype(void(std::declval() + >> std::declval()), + std::true_type()); + +std::false_type g(...); + +void test01() +{ + Y y; + std::wistringstream is; + is >> y; + is >> Y(); + std::wistringstream() >> y; + std::wistringstream() >> Y(); + static_assert(!std::__is_extractable::value, ""); + static_assert(!std::__is_extractable::value, ""); + static_assert(!std::__is_extractable::value, ""); + static_assert(!std::__is_extractable::value, ""); + static_assert(std::__is_extractable::value, ""); + static_assert(std::__is_extractable::value, ""); + static_assert(std::__is_extractable::value, ""); + static_assert(std::__is_extractable::value, ""); + static_assert(!std::__is_extractable::value, ""); + static_assert(!std::__is_extractable::value, ""); + static_assert(!std::__is_extractable::value, ""); + static_assert(!std::__is_extractable::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); + static_assert(std::is_same())), + std::true_type>::value, ""); + static_assert(std::is_same())), + std::true_type>::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); + static_assert(std::is_same())), + std::true_type>::value, ""); + static_assert(std::is_same())), + std::true_type>::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); +} + +int main() +{ + test01(); +} diff --git a/libstdc++-v3/testsuite/27_io/basic_ostream/inserters_other/char/6.cc b/libstdc++-v3/testsuite/27_io/basic_ostream/inserters_other/char/6.cc new file mode 100644 index 00000000000..f5b27f9ce1b --- /dev/null +++ b/libstdc++-v3/testsuite/27_io/basic_ostream/inserters_other/char/6.cc @@ -0,0 +1,96 @@ +// { dg-do run { target c++11 } } + +// Copyright (C) 2016 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 +// . + +// 27.6.2.5.3 basic_ostream manipulator inserters + +#include + +struct X {}; +std::ostream& operator<<(std::ostream&, const X&) = delete; + +struct Y {}; +std::ostream& operator<<(std::ostream& os, const Y&) {return os;} +std::ostream& operator<<(std::ostream&& os, const Y&) {return os;} + +struct Z{}; + +template +auto f(T&&) -> decltype(void(std::declval() + << std::declval()), + std::true_type()); + +std::false_type f(...); + +template +auto g(T&&) -> decltype(void(std::declval() + << std::declval()), + std::true_type()); + +std::false_type g(...); + +void test01() +{ + Y y; + std::ostringstream os; + os << y; + os << Y(); + std::ostringstream() << y; + std::ostringstream() << Y(); + static_assert(!std::__is_insertable::value, ""); + static_assert(!std::__is_insertable::value, ""); + static_assert(!std::__is_insertable::value, ""); + static_assert(!std::__is_insertable::value, ""); + static_assert(std::__is_insertable::value, ""); + static_assert(std::__is_insertable::value, ""); + static_assert(std::__is_insertable::value, ""); + static_assert(std::__is_insertable::value, ""); + static_assert(!std::__is_insertable::value, ""); + static_assert(!std::__is_insertable::value, ""); + static_assert(!std::__is_insertable::value, ""); + static_assert(!std::__is_insertable::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); + static_assert(std::is_same())), + std::true_type>::value, ""); + static_assert(std::is_same())), + std::true_type>::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); + static_assert(std::is_same())), + std::true_type>::value, ""); + static_assert(std::is_same())), + std::true_type>::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); +} + +int main() +{ + test01(); +} diff --git a/libstdc++-v3/testsuite/27_io/basic_ostream/inserters_other/wchar_t/6.cc b/libstdc++-v3/testsuite/27_io/basic_ostream/inserters_other/wchar_t/6.cc new file mode 100644 index 00000000000..1aed058f2e6 --- /dev/null +++ b/libstdc++-v3/testsuite/27_io/basic_ostream/inserters_other/wchar_t/6.cc @@ -0,0 +1,96 @@ +// { dg-do run { target c++11 } } + +// Copyright (C) 2016 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 +// . + +// 27.6.2.5.3 basic_ostream manipulator inserters + +#include + +struct X {}; +std::wostream& operator<<(std::wostream&, const X&) = delete; + +struct Y {}; +std::wostream& operator<<(std::wostream& os, const Y&) {return os;} +std::wostream& operator<<(std::wostream&& os, const Y&) {return os;} + +struct Z{}; + +template +auto f(T&&) -> decltype(void(std::declval() + << std::declval()), + std::true_type()); + +std::false_type f(...); + +template +auto g(T&&) -> decltype(void(std::declval() + << std::declval()), + std::true_type()); + +std::false_type g(...); + +void test01() +{ + Y y; + std::wostringstream os; + os << y; + os << Y(); + std::wostringstream() << y; + std::wostringstream() << Y(); + static_assert(!std::__is_insertable::value, ""); + static_assert(!std::__is_insertable::value, ""); + static_assert(!std::__is_insertable::value, ""); + static_assert(!std::__is_insertable::value, ""); + static_assert(std::__is_insertable::value, ""); + static_assert(std::__is_insertable::value, ""); + static_assert(std::__is_insertable::value, ""); + static_assert(std::__is_insertable::value, ""); + static_assert(!std::__is_insertable::value, ""); + static_assert(!std::__is_insertable::value, ""); + static_assert(!std::__is_insertable::value, ""); + static_assert(!std::__is_insertable::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); + static_assert(std::is_same())), + std::true_type>::value, ""); + static_assert(std::is_same())), + std::true_type>::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); + static_assert(std::is_same())), + std::true_type>::value, ""); + static_assert(std::is_same())), + std::true_type>::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); + static_assert(std::is_same())), + std::false_type>::value, ""); +} + +int main() +{ + test01(); +}