| Message ID | 20170913140903.GA8606@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | PR libstdc++/81468 constrain std::chrono::time_point constructor | expand |
On 13/09/17 15:09 +0100, Jonathan Wakely wrote: >Howard reported this bug, caused by a missing SFINAE constraint on a >std::chrono::time_point constructor. > >I've also done a bit of simplification using alias templates. Here's the backport for the branches, which just adds the constraint (and tests) without the new alias templates. commit 4a6c846f3203dd0ceb13b7130e686833a4150d96 Author: Jonathan Wakely <jwakely@redhat.com> Date: Wed Sep 13 15:16:31 2017 +0100 PR libstdc++/81468 constrain std::chrono::time_point constructor PR libstdc++/81468 * include/std/chrono (time_point(const time_point<_Dur2>&)): Add missing constraint from LWG DR 1177. * testsuite/20_util/duration/cons/dr1177.cc: New. * testsuite/20_util/time_point/cons/81468.cc: New. * testsuite/20_util/duration/literals/range.cc: Update dg-error line. diff --git a/libstdc++-v3/include/std/chrono b/libstdc++-v3/include/std/chrono index c3a6ba8f873..cc63d44657b 100644 --- a/libstdc++-v3/include/std/chrono +++ b/libstdc++-v3/include/std/chrono @@ -622,7 +622,8 @@ _GLIBCXX_END_NAMESPACE_VERSION { } // conversions - template<typename _Dur2> + template<typename _Dur2, + typename = _Require<is_convertible<_Dur2, _Dur>>> constexpr time_point(const time_point<clock, _Dur2>& __t) : __d(__t.time_since_epoch()) { } diff --git a/libstdc++-v3/testsuite/20_util/duration/cons/dr1177.cc b/libstdc++-v3/testsuite/20_util/duration/cons/dr1177.cc new file mode 100644 index 00000000000..28c881ccc79 --- /dev/null +++ b/libstdc++-v3/testsuite/20_util/duration/cons/dr1177.cc @@ -0,0 +1,41 @@ +// Copyright (C) 2017 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 <chrono> +#include <type_traits> + +using namespace std; +using namespace std::chrono; + +// DR 1177 +static_assert(is_constructible<duration<float>, duration<double>>{}, + "can convert duration with one floating point rep to another"); +static_assert(is_constructible<duration<float>, duration<int>>{}, + "can convert duration with integral rep to one with floating point rep"); +static_assert(!is_constructible<duration<int>, duration<float>>{}, + "cannot convert duration with floating point rep to one with integral rep"); +static_assert(is_constructible<duration<int>, duration<long>>{}, + "can convert duration with one integral rep to another"); + +static_assert(!is_constructible<duration<int>, duration<int, ratio<2,3>>>{}, + "cannot convert duration to one with different period"); +static_assert(is_constructible<duration<float>, duration<int, ratio<2,3>>>{}, + "unless it has a floating-point representation"); +static_assert(is_constructible<duration<float>, duration<int, ratio<1,3>>>{}, + "or a period that is an integral multiple of the original"); diff --git a/libstdc++-v3/testsuite/20_util/duration/literals/range.cc b/libstdc++-v3/testsuite/20_util/duration/literals/range.cc index c0d1a6e5885..531b53c42ec 100644 --- a/libstdc++-v3/testsuite/20_util/duration/literals/range.cc +++ b/libstdc++-v3/testsuite/20_util/duration/literals/range.cc @@ -26,6 +26,6 @@ test01() // std::numeric_limits<int64_t>::max() == 9223372036854775807; auto h = 9223372036854775808h; - // { dg-error "cannot be represented" "" { target *-*-* } 892 } + // { dg-error "cannot be represented" "" { target *-*-* } 893 } } // { dg-prune-output "in constexpr expansion" } // needed for -O0 diff --git a/libstdc++-v3/testsuite/20_util/time_point/cons/81468.cc b/libstdc++-v3/testsuite/20_util/time_point/cons/81468.cc new file mode 100644 index 00000000000..30d1c4a5ac7 --- /dev/null +++ b/libstdc++-v3/testsuite/20_util/time_point/cons/81468.cc @@ -0,0 +1,34 @@ +// Copyright (C) 2017 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 <chrono> +#include <type_traits> + +using namespace std; +using namespace std::chrono; + +template <class Duration> + using sys_time = time_point<system_clock, Duration>; + +static_assert(is_constructible<sys_time<milliseconds>, sys_time<seconds>>{}, + "Can construct time_point from one with lower precision duration"); + +// PR libstdc++/81468 - DR 1177 +static_assert(!is_constructible<sys_time<seconds>, sys_time<milliseconds>>{}, + "Cannot construct time_point from one with higher precision duration");
On Wed, Sep 13, 2017 at 10:55 AM, Jonathan Wakely <jwakely@redhat.com> wrote: > > +// DR 1177 > +static_assert(is_constructible<duration<float>, duration<double>>{}, > + "can convert duration with one floating point rep to another"); > +static_assert(is_constructible<duration<float>, duration<int>>{}, > + "can convert duration with integral rep to one with floating point rep"); > +static_assert(!is_constructible<duration<int>, duration<float>>{}, > + "cannot convert duration with floating point rep to one with integral rep"); > +static_assert(is_constructible<duration<int>, duration<long>>{}, > + "can convert duration with one integral rep to another"); > + > +static_assert(!is_constructible<duration<int>, duration<int, ratio<2,3>>>{}, > + "cannot convert duration to one with different period"); > +static_assert(is_constructible<duration<float>, duration<int, ratio<2,3>>>{}, > + "unless it has a floating-point representation"); "it" is a little ambiguous here unless you read the next message's mention of "the original"... > +static_assert(is_constructible<duration<float>, duration<int, ratio<1,3>>>{}, > + "or a period that is an integral multiple of the original"); This is backwards: duration<Inty, P1> is convertible to duration<Inty, P2> iff P1 is an integral multiple of P2, i.e., if the original's period is an integral multiple of "its" period. The static assert only passed because duration<float> was used as the destination type (presumably because of a copy/paste error). Tim
On 13/09/17 21:30 -0400, Tim Song wrote: >On Wed, Sep 13, 2017 at 10:55 AM, Jonathan Wakely <jwakely@redhat.com> wrote: >> >> +// DR 1177 >> +static_assert(is_constructible<duration<float>, duration<double>>{}, >> + "can convert duration with one floating point rep to another"); >> +static_assert(is_constructible<duration<float>, duration<int>>{}, >> + "can convert duration with integral rep to one with floating point rep"); >> +static_assert(!is_constructible<duration<int>, duration<float>>{}, >> + "cannot convert duration with floating point rep to one with integral rep"); >> +static_assert(is_constructible<duration<int>, duration<long>>{}, >> + "can convert duration with one integral rep to another"); >> + >> +static_assert(!is_constructible<duration<int>, duration<int, ratio<2,3>>>{}, >> + "cannot convert duration to one with different period"); >> +static_assert(is_constructible<duration<float>, duration<int, ratio<2,3>>>{}, >> + "unless it has a floating-point representation"); > >"it" is a little ambiguous here unless you read the next message's >mention of "the original"... > >> +static_assert(is_constructible<duration<float>, duration<int, ratio<1,3>>>{}, >> + "or a period that is an integral multiple of the original"); > >This is backwards: duration<Inty, P1> is convertible to duration<Inty, >P2> iff P1 is an integral multiple of P2, i.e., if the original's >period is an integral multiple of "its" period. > >The static assert only passed because duration<float> was used as the >destination type (presumably because of a copy/paste error). > >Tim Good catch, thanks. I've committed this patch. commit 5c021e19e0758e5ad7e47feadbd0632b15f85785 Author: Jonathan Wakely <jwakely@redhat.com> Date: Mon Sep 18 19:04:25 2017 +0100 PR libstdc++/81468 fix test for duration conversions PR libstdc++/81468 * testsuite/20_util/duration/cons/dr1177.cc: Fix incorrect test and improve static assertion messages. diff --git a/libstdc++-v3/testsuite/20_util/duration/cons/dr1177.cc b/libstdc++-v3/testsuite/20_util/duration/cons/dr1177.cc index 28c881ccc79..d90cd27f482 100644 --- a/libstdc++-v3/testsuite/20_util/duration/cons/dr1177.cc +++ b/libstdc++-v3/testsuite/20_util/duration/cons/dr1177.cc @@ -36,6 +36,6 @@ static_assert(is_constructible<duration<int>, duration<long>>{}, static_assert(!is_constructible<duration<int>, duration<int, ratio<2,3>>>{}, "cannot convert duration to one with different period"); static_assert(is_constructible<duration<float>, duration<int, ratio<2,3>>>{}, - "unless it has a floating-point representation"); -static_assert(is_constructible<duration<float>, duration<int, ratio<1,3>>>{}, - "or a period that is an integral multiple of the original"); + "... unless the result type has a floating-point representation"); +static_assert(is_constructible<duration<int, ratio<1,3>>, duration<int>>{}, + "... or the original's period is a multiple of the result's period");
diff --git a/libstdc++-v3/include/std/chrono b/libstdc++-v3/include/std/chrono index 1bcbf524a7b..fc058fcd8d8 100644 --- a/libstdc++-v3/include/std/chrono +++ b/libstdc++-v3/include/std/chrono @@ -179,10 +179,17 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION : std::true_type { }; + template<typename _Tp> + using __enable_if_is_duration + = typename enable_if<__is_duration<_Tp>::value, _Tp>::type; + + template<typename _Tp> + using __disable_if_is_duration + = typename enable_if<!__is_duration<_Tp>::value, _Tp>::type; + /// duration_cast template<typename _ToDur, typename _Rep, typename _Period> - constexpr typename enable_if<__is_duration<_ToDur>::value, - _ToDur>::type + constexpr __enable_if_is_duration<_ToDur> duration_cast(const duration<_Rep, _Period>& __d) { typedef typename _ToDur::period __to_period; @@ -211,7 +218,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION # define __cpp_lib_chrono 201510 template<typename _ToDur, typename _Rep, typename _Period> - constexpr enable_if_t<__is_duration<_ToDur>::value, _ToDur> + constexpr __enable_if_is_duration<_ToDur> floor(const duration<_Rep, _Period>& __d) { auto __to = chrono::duration_cast<_ToDur>(__d); @@ -221,7 +228,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION } template<typename _ToDur, typename _Rep, typename _Period> - constexpr enable_if_t<__is_duration<_ToDur>::value, _ToDur> + constexpr __enable_if_is_duration<_ToDur> ceil(const duration<_Rep, _Period>& __d) { auto __to = chrono::duration_cast<_ToDur>(__d); @@ -294,6 +301,17 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION template<typename _Rep, typename _Period> struct duration { + private: + template<typename _Rep2> + using __is_float = treat_as_floating_point<_Rep2>; + + // _Period2 is an exact multiple of _Period + template<typename _Period2> + using __is_harmonic + = __bool_constant<ratio_divide<_Period2, _Period>::den == 1>; + + public: + typedef _Rep rep; typedef _Period period; @@ -305,22 +323,18 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION // 20.11.5.1 construction / copy / destroy constexpr duration() = default; - // NB: Make constexpr implicit. This cannot be explicitly - // constexpr, as any UDT that is not a literal type with a - // constexpr copy constructor will be ill-formed. duration(const duration&) = default; - template<typename _Rep2, typename = typename - enable_if<is_convertible<_Rep2, rep>::value - && (treat_as_floating_point<rep>::value - || !treat_as_floating_point<_Rep2>::value)>::type> + template<typename _Rep2, typename = _Require< + is_convertible<_Rep2, rep>, + __or_<__is_float<rep>, __not_<__is_float<_Rep2>>>>> constexpr explicit duration(const _Rep2& __rep) : __r(static_cast<rep>(__rep)) { } - template<typename _Rep2, typename _Period2, typename = typename - enable_if<treat_as_floating_point<rep>::value - || (ratio_divide<_Period2, period>::den == 1 - && !treat_as_floating_point<_Rep2>::value)>::type> + template<typename _Rep2, typename _Period2, typename = _Require< + __or_<__is_float<rep>, + __and_<__is_harmonic<_Period2>, + __not_<__is_float<_Rep2>>>>>> constexpr duration(const duration<_Rep2, _Period2>& __d) : __r(duration_cast<duration>(__d).count()) { } @@ -455,18 +469,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION return __cd(__cd(__lhs).count() - __cd(__rhs).count()); } - template<typename _Rep1, typename _Rep2, bool = - is_convertible<_Rep2, - typename common_type<_Rep1, _Rep2>::type>::value> - struct __common_rep_type { }; - - template<typename _Rep1, typename _Rep2> - struct __common_rep_type<_Rep1, _Rep2, true> - { typedef typename common_type<_Rep1, _Rep2>::type type; }; + // SFINAE helper to obtain common_type<_Rep1, _Rep2> only if _Rep2 + // is implicitly convertible to it. + template<typename _Rep1, typename _Rep2, + typename _CRep = typename common_type<_Rep1, _Rep2>::type> + using __common_rep_t + = typename enable_if<is_convertible<_Rep2, _CRep>::value, _CRep>::type; template<typename _Rep1, typename _Period, typename _Rep2> - constexpr - duration<typename __common_rep_type<_Rep1, _Rep2>::type, _Period> + constexpr duration<__common_rep_t<_Rep1, _Rep2>, _Period> operator*(const duration<_Rep1, _Period>& __d, const _Rep2& __s) { typedef duration<typename common_type<_Rep1, _Rep2>::type, _Period> @@ -475,14 +486,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION } template<typename _Rep1, typename _Rep2, typename _Period> - constexpr - duration<typename __common_rep_type<_Rep2, _Rep1>::type, _Period> + constexpr duration<__common_rep_t<_Rep2, _Rep1>, _Period> operator*(const _Rep1& __s, const duration<_Rep2, _Period>& __d) { return __d * __s; } template<typename _Rep1, typename _Period, typename _Rep2> - constexpr duration<typename __common_rep_type<_Rep1, typename - enable_if<!__is_duration<_Rep2>::value, _Rep2>::type>::type, _Period> + constexpr + duration<__common_rep_t<_Rep1, __disable_if_is_duration<_Rep2>>, _Period> operator/(const duration<_Rep1, _Period>& __d, const _Rep2& __s) { typedef duration<typename common_type<_Rep1, _Rep2>::type, _Period> @@ -504,8 +514,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION // DR 934. template<typename _Rep1, typename _Period, typename _Rep2> - constexpr duration<typename __common_rep_type<_Rep1, typename - enable_if<!__is_duration<_Rep2>::value, _Rep2>::type>::type, _Period> + constexpr + duration<__common_rep_t<_Rep1, __disable_if_is_duration<_Rep2>>, _Period> operator%(const duration<_Rep1, _Period>& __d, const _Rep2& __s) { typedef duration<typename common_type<_Rep1, _Rep2>::type, _Period> @@ -614,7 +624,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION { } // conversions - template<typename _Dur2> + template<typename _Dur2, + typename = _Require<is_convertible<_Dur2, _Dur>>> constexpr time_point(const time_point<clock, _Dur2>& __t) : __d(__t.time_since_epoch()) { } diff --git a/libstdc++-v3/testsuite/20_util/duration/cons/dr1177.cc b/libstdc++-v3/testsuite/20_util/duration/cons/dr1177.cc new file mode 100644 index 00000000000..28c881ccc79 --- /dev/null +++ b/libstdc++-v3/testsuite/20_util/duration/cons/dr1177.cc @@ -0,0 +1,41 @@ +// Copyright (C) 2017 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 <chrono> +#include <type_traits> + +using namespace std; +using namespace std::chrono; + +// DR 1177 +static_assert(is_constructible<duration<float>, duration<double>>{}, + "can convert duration with one floating point rep to another"); +static_assert(is_constructible<duration<float>, duration<int>>{}, + "can convert duration with integral rep to one with floating point rep"); +static_assert(!is_constructible<duration<int>, duration<float>>{}, + "cannot convert duration with floating point rep to one with integral rep"); +static_assert(is_constructible<duration<int>, duration<long>>{}, + "can convert duration with one integral rep to another"); + +static_assert(!is_constructible<duration<int>, duration<int, ratio<2,3>>>{}, + "cannot convert duration to one with different period"); +static_assert(is_constructible<duration<float>, duration<int, ratio<2,3>>>{}, + "unless it has a floating-point representation"); +static_assert(is_constructible<duration<float>, duration<int, ratio<1,3>>>{}, + "or a period that is an integral multiple of the original"); diff --git a/libstdc++-v3/testsuite/20_util/duration/literals/range.cc b/libstdc++-v3/testsuite/20_util/duration/literals/range.cc index b5105dff38b..36e71eea72b 100644 --- a/libstdc++-v3/testsuite/20_util/duration/literals/range.cc +++ b/libstdc++-v3/testsuite/20_util/duration/literals/range.cc @@ -26,6 +26,6 @@ test01() // std::numeric_limits<int64_t>::max() == 9223372036854775807; auto h = 9223372036854775808h; - // { dg-error "cannot be represented" "" { target *-*-* } 880 } + // { dg-error "cannot be represented" "" { target *-*-* } 891 } } // { dg-prune-output "in constexpr expansion" } // needed for -O0 diff --git a/libstdc++-v3/testsuite/20_util/duration/requirements/typedefs_neg1.cc b/libstdc++-v3/testsuite/20_util/duration/requirements/typedefs_neg1.cc index 17f74187098..d57f6dedd66 100644 --- a/libstdc++-v3/testsuite/20_util/duration/requirements/typedefs_neg1.cc +++ b/libstdc++-v3/testsuite/20_util/duration/requirements/typedefs_neg1.cc @@ -30,4 +30,4 @@ void test01() test_type d; // { dg-error "required from here" } } -// { dg-error "rep cannot be a duration" "" { target *-*-* } 300 } +// { dg-error "rep cannot be a duration" "" { target *-*-* } 318 } diff --git a/libstdc++-v3/testsuite/20_util/duration/requirements/typedefs_neg2.cc b/libstdc++-v3/testsuite/20_util/duration/requirements/typedefs_neg2.cc index 282a9dbdc85..39283b2cb74 100644 --- a/libstdc++-v3/testsuite/20_util/duration/requirements/typedefs_neg2.cc +++ b/libstdc++-v3/testsuite/20_util/duration/requirements/typedefs_neg2.cc @@ -31,5 +31,5 @@ void test01() test_type d; // { dg-error "required from here" } } -// { dg-error "must be a specialization of ratio" "" { target *-*-* } 301 } +// { dg-error "must be a specialization of ratio" "" { target *-*-* } 319 } // { dg-prune-output "not a member" } diff --git a/libstdc++-v3/testsuite/20_util/duration/requirements/typedefs_neg3.cc b/libstdc++-v3/testsuite/20_util/duration/requirements/typedefs_neg3.cc index c57f9d947a5..9beaa83fbfa 100644 --- a/libstdc++-v3/testsuite/20_util/duration/requirements/typedefs_neg3.cc +++ b/libstdc++-v3/testsuite/20_util/duration/requirements/typedefs_neg3.cc @@ -32,4 +32,4 @@ void test01() test_type d; // { dg-error "required from here" } } -// { dg-error "period must be positive" "" { target *-*-* } 303 } +// { dg-error "period must be positive" "" { target *-*-* } 321 } diff --git a/libstdc++-v3/testsuite/20_util/time_point/cons/81468.cc b/libstdc++-v3/testsuite/20_util/time_point/cons/81468.cc new file mode 100644 index 00000000000..30d1c4a5ac7 --- /dev/null +++ b/libstdc++-v3/testsuite/20_util/time_point/cons/81468.cc @@ -0,0 +1,34 @@ +// Copyright (C) 2017 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 <chrono> +#include <type_traits> + +using namespace std; +using namespace std::chrono; + +template <class Duration> + using sys_time = time_point<system_clock, Duration>; + +static_assert(is_constructible<sys_time<milliseconds>, sys_time<seconds>>{}, + "Can construct time_point from one with lower precision duration"); + +// PR libstdc++/81468 - DR 1177 +static_assert(!is_constructible<sys_time<seconds>, sys_time<milliseconds>>{}, + "Cannot construct time_point from one with higher precision duration");
Howard reported this bug, caused by a missing SFINAE constraint on a std::chrono::time_point constructor. I've also done a bit of simplification using alias templates. PR libstdc++/81468 * include/std/chrono (__enable_if_is_duration) (__disable_if_is_duration): New alias templates to simplify SFINAE. (duration_cast, floor, ceil): Use __enable_if_is_duration. (duration::__is_float, duration::__is_harmonic): New alias templates to simplify SFINAE. (duration::duration(const _Rep2&)): Use _Require, __is_float and __is_harmonic. (duration::duration(const duration<_Rep2, _Period2>&)): Likewise. (__common_rep_type): Remove, replace with ... (__common_rep_t): New alias template. (operator*, operator/, operator%): Use __common_rep_t and __disable_if_is_duration. (time_point::time_point(const time_point<clock, _Dur2>&)): Add missing constraint from LWG DR 1177. * testsuite/20_util/duration/cons/dr1177.cc: New. * testsuite/20_util/duration/literals/range.cc: Update dg-error line. * testsuite/20_util/duration/requirements/typedefs_neg1.cc: Likewise. * testsuite/20_util/duration/requirements/typedefs_neg2.cc: Likewise. * testsuite/20_util/duration/requirements/typedefs_neg3.cc: Likewise. * testsuite/20_util/time_point/cons/81468.cc: New. Tested on powerp64le-linux, committed to trunk. commit e06db0fa47676eeb386bfd1a582a005d341fb678 Author: Jonathan Wakely <jwakely@redhat.com> Date: Wed Sep 13 13:00:50 2017 +0100 PR libstdc++/81468 constrain std::chrono::time_point constructor PR libstdc++/81468 * include/std/chrono (__enable_if_is_duration) (__disable_if_is_duration): New alias templates to simplify SFINAE. (duration_cast, floor, ceil): Use __enable_if_is_duration. (duration::__is_float, duration::__is_harmonic): New alias templates to simplify SFINAE. (duration::duration(const _Rep2&)): Use _Require, __is_float and __is_harmonic. (duration::duration(const duration<_Rep2, _Period2>&)): Likewise. (__common_rep_type): Remove, replace with ... (__common_rep_t): New alias template. (operator*, operator/, operator%): Use __common_rep_t and __disable_if_is_duration. (time_point::time_point(const time_point<clock, _Dur2>&)): Add missing constraint from LWG DR 1177. * testsuite/20_util/duration/cons/dr1177.cc: New. * testsuite/20_util/duration/literals/range.cc: Update dg-error line. * testsuite/20_util/duration/requirements/typedefs_neg1.cc: Likewise. * testsuite/20_util/duration/requirements/typedefs_neg2.cc: Likewise. * testsuite/20_util/duration/requirements/typedefs_neg3.cc: Likewise. * testsuite/20_util/time_point/cons/81468.cc: New.