PR libstdc++/89102 implement new common_type rules (P0435R1, P0548R1)
This change ensures that std::common_type<> is a complete type (LWG 2408), and that std::common_type<T>, std::common_type<cv T1, cv T2>, and std::common_type<T1, T2, R...> will use program-defined specializations for std::common_type<T1, T2> (LWG 2465). The implementation of common_type<T1, T2, R...> is changed to use void_t, and the specializations for duration and time_point are modified to also use void_t instead of depending on implementation details of common_type. PR libstdc++/89102 * doc/xml/manual/intro.xml: Document DR 2408 and 2465 changes. * include/std/chrono (__duration_common_type_wrapper): Replace with ... (__duration_common_type): New helper. (common_type<chrono::duration<R1, P2>, chrono::duration<R2, P2>>): Use __duration_common_type. (__timepoint_common_type_wrapper): Replace with ... (__timepoint_common_type): New helper. (common_type<chrono::time_point<C, D2>, chrono::time_point<C, D2>>): Use __time_point_common_type. * include/std/type_traits (common_type<>): Define, as per LWG 2408. (__common_type_impl): If either argument is transformed by decay, use the common_type of the decayed types. (__common_type_impl<_Tp, _Up, _Tp, _Up>): If the types are already decayed, use __do_common_type_impl to get the common_type. (common_type<_Tp>): Use common_type<_Tp, _Tp>. (__do_member_type_wrapper, __member_type_wrapper) (__expanded_common_type_wrapper): Remove. (__common_type_pack, __common_type_fold): New helpers. (common_type<_Tp, _Up, _Vp...>): Use new helpers instead of __member_type_wrapper and __expanded_common_type_wrapper. * testsuite/20_util/common_type/requirements/explicit_instantiation.cc: Test zero-length template argument list. * testsuite/20_util/common_type/requirements/sfinae_friendly_1.cc: Test single argument cases and argument types that should decay. * testsuite/20_util/common_type/requirements/sfinae_friendly_2.cc: Adjust expected error. * testsuite/20_util/duration/literals/range_neg.cc: Use zero for dg-error lineno. * 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. From-SVN: r270987
This commit is contained in:
Jonathan Wakely
Jonathan Wakely
parent
f7f36e3dc1
commit
f61a12b395
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@ -1,5 +1,38 @@
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2019-05-07 Jonathan Wakely <jwakely@redhat.com>
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PR libstdc++/89102
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* doc/xml/manual/intro.xml: Document DR 2408 and 2465 changes.
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* include/std/chrono (__duration_common_type_wrapper): Replace with ...
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(__duration_common_type): New helper.
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(common_type<chrono::duration<R1, P2>, chrono::duration<R2, P2>>): Use
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__duration_common_type.
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(__timepoint_common_type_wrapper): Replace with ...
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(__timepoint_common_type): New helper.
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(common_type<chrono::time_point<C, D2>, chrono::time_point<C, D2>>):
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Use __time_point_common_type.
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* include/std/type_traits (common_type<>): Define, as per LWG 2408.
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(__common_type_impl): If either argument is transformed by decay,
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use the common_type of the decayed types.
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(__common_type_impl<_Tp, _Up, _Tp, _Up>): If the types are already
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decayed, use __do_common_type_impl to get the common_type.
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(common_type<_Tp>): Use common_type<_Tp, _Tp>.
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(__do_member_type_wrapper, __member_type_wrapper)
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(__expanded_common_type_wrapper): Remove.
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(__common_type_pack, __common_type_fold): New helpers.
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(common_type<_Tp, _Up, _Vp...>): Use new helpers instead of
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__member_type_wrapper and __expanded_common_type_wrapper.
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* testsuite/20_util/common_type/requirements/explicit_instantiation.cc:
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Test zero-length template argument list.
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* testsuite/20_util/common_type/requirements/sfinae_friendly_1.cc:
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Test single argument cases and argument types that should decay.
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* testsuite/20_util/common_type/requirements/sfinae_friendly_2.cc:
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Adjust expected error.
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* testsuite/20_util/duration/literals/range_neg.cc: Use zero for
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dg-error lineno.
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* testsuite/20_util/duration/requirements/typedefs_neg1.cc: Likewise.
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* testsuite/20_util/duration/requirements/typedefs_neg2.cc: Likewise.
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* testsuite/20_util/duration/requirements/typedefs_neg3.cc: Likewise.
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* doc/xml/manual/intro.xml: Fix DR 2537 and DR 2566 confusion.
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2019-05-01 Nina Dinka Ranns <dinka.ranns@gmail.com>
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@ -1045,6 +1045,17 @@ requirements of the license of GCC.
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<listitem><para>Remove <code>explicit</code> from the constructor.
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</para></listitem></varlistentry>
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<varlistentry xml:id="manual.bugs.dr2408"><term><link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="&DR;#2408">2408</link>:
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<emphasis>SFINAE-friendly
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<code>common_type</code>/<code>iterator_traits</code>
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is missing in C++14
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</emphasis>
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</term>
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<listitem><para>Make <code>iterator_traits</code> empty if any of the
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types is not present in the iterator.
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Make <code>common_type<></code> empty.
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</para></listitem></varlistentry>
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<varlistentry xml:id="manual.bugs.dr2415"><term><link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="&DR;#2415">2415</link>:
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<emphasis>Inconsistency between <code>unique_ptr</code> and <code>shared_ptr</code></emphasis>
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</term>
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@ -1105,6 +1116,15 @@ requirements of the license of GCC.
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<listitem><para>Add debug mode assertion.
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</para></listitem></varlistentry>
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<varlistentry xml:id="manual.bugs.dr2465"><term><link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="&DR;#2465">2465</link>:
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<emphasis>SFINAE-friendly <code>common_type</code> is nearly impossible
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to specialize correctly and regresses key functionality
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</emphasis>
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</term>
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<listitem><para>Detect whether <code>decay_t</code> changes either type
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and use the decayed types if so.
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</para></listitem></varlistentry>
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<varlistentry xml:id="manual.bugs.dr2466"><term><link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="&DR;#2466">2466</link>:
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<emphasis><code>allocator_traits::max_size()</code> default behavior is incorrect
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</emphasis>
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@ -67,48 +67,51 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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// 20.11.4.3 specialization of common_type (for duration, sfinae-friendly)
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template<typename _CT, typename _Period1, typename _Period2, typename = void>
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struct __duration_common_type
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{ };
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template<typename _CT, typename _Period1, typename _Period2>
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struct __duration_common_type_wrapper
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struct __duration_common_type<_CT, _Period1, _Period2,
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__void_t<typename _CT::type>>
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{
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private:
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typedef __static_gcd<_Period1::num, _Period2::num> __gcd_num;
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typedef __static_gcd<_Period1::den, _Period2::den> __gcd_den;
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typedef typename _CT::type __cr;
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typedef ratio<__gcd_num::value,
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(_Period1::den / __gcd_den::value) * _Period2::den> __r;
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using __gcd_num = __static_gcd<_Period1::num, _Period2::num>;
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using __gcd_den = __static_gcd<_Period1::den, _Period2::den>;
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using __cr = typename _CT::type;
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using __r = ratio<__gcd_num::value,
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(_Period1::den / __gcd_den::value) * _Period2::den>;
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public:
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typedef __success_type<chrono::duration<__cr, __r>> type;
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using type = chrono::duration<__cr, __r>;
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};
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template<typename _Period1, typename _Period2>
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struct __duration_common_type_wrapper<__failure_type, _Period1, _Period2>
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struct __duration_common_type<__failure_type, _Period1, _Period2>
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{ typedef __failure_type type; };
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template<typename _Rep1, typename _Period1, typename _Rep2, typename _Period2>
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struct common_type<chrono::duration<_Rep1, _Period1>,
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chrono::duration<_Rep2, _Period2>>
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: public __duration_common_type_wrapper<typename __member_type_wrapper<
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common_type<_Rep1, _Rep2>>::type, _Period1, _Period2>::type
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chrono::duration<_Rep2, _Period2>>
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: __duration_common_type<common_type<_Rep1, _Rep2>, _Period1, _Period2>
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{ };
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// 20.11.4.3 specialization of common_type (for time_point, sfinae-friendly)
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template<typename _CT, typename _Clock>
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struct __timepoint_common_type_wrapper
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{
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typedef __success_type<chrono::time_point<_Clock, typename _CT::type>>
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type;
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};
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template<typename _CT, typename _Clock, typename = void>
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struct __timepoint_common_type
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{ };
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template<typename _Clock>
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struct __timepoint_common_type_wrapper<__failure_type, _Clock>
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{ typedef __failure_type type; };
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template<typename _CT, typename _Clock>
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struct __timepoint_common_type<_CT, _Clock, __void_t<typename _CT::type>>
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{
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using type = chrono::time_point<_Clock, typename _CT::type>;
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};
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template<typename _Clock, typename _Duration1, typename _Duration2>
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struct common_type<chrono::time_point<_Clock, _Duration1>,
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chrono::time_point<_Clock, _Duration2>>
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: public __timepoint_common_type_wrapper<typename __member_type_wrapper<
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common_type<_Duration1, _Duration2>>::type, _Clock>::type
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chrono::time_point<_Clock, _Duration2>>
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: __timepoint_common_type<common_type<_Duration1, _Duration2>, _Clock>
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{ };
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namespace chrono
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@ -2106,6 +2106,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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struct conditional<false, _Iftrue, _Iffalse>
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{ typedef _Iffalse type; };
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// __void_t (std::void_t for C++11)
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template<typename...> using __void_t = void;
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/// common_type
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template<typename... _Tp>
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struct common_type;
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@ -2115,65 +2118,81 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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struct __do_common_type_impl
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{
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template<typename _Tp, typename _Up>
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static __success_type<typename decay<decltype
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(true ? std::declval<_Tp>()
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: std::declval<_Up>())>::type> _S_test(int);
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using __cond_t
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= decltype(true ? std::declval<_Tp>() : std::declval<_Up>());
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template<typename _Tp, typename _Up>
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static __success_type<typename decay<__cond_t<_Tp, _Up>>::type>
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_S_test(int);
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template<typename, typename>
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static __failure_type _S_test(...);
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static __failure_type
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_S_test(...);
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};
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template<typename _Tp, typename _Up>
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struct __common_type_impl
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: private __do_common_type_impl
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{
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typedef decltype(_S_test<_Tp, _Up>(0)) type;
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};
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struct __do_member_type_wrapper
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{
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template<typename _Tp>
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static __success_type<typename _Tp::type> _S_test(int);
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template<typename>
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static __failure_type _S_test(...);
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};
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template<typename _Tp>
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struct __member_type_wrapper
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: private __do_member_type_wrapper
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{
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typedef decltype(_S_test<_Tp>(0)) type;
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};
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template<typename _CTp, typename... _Args>
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struct __expanded_common_type_wrapper
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{
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typedef common_type<typename _CTp::type, _Args...> type;
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};
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template<typename... _Args>
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struct __expanded_common_type_wrapper<__failure_type, _Args...>
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{ typedef __failure_type type; };
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// If sizeof...(T) is zero, there shall be no member type.
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template<>
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struct common_type<>
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{ };
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template<typename _Tp>
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struct common_type<_Tp>
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: common_type<_Tp, _Tp>
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// If sizeof...(T) is one, the same type, if any, as common_type_t<T0, T0>.
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template<typename _Tp0>
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struct common_type<_Tp0>
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: public common_type<_Tp0, _Tp0>
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{ };
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template<typename _Tp, typename _Up>
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struct common_type<_Tp, _Up>
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: public __common_type_impl<_Tp, _Up>::type
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// If sizeof...(T) is two, ...
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template<typename _Tp1, typename _Tp2,
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typename _Dp1 = typename decay<_Tp1>::type,
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typename _Dp2 = typename decay<_Tp2>::type>
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struct __common_type_impl
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{
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// If is_same_v<T1, D1> is false or is_same_v<T2, D2> is false,
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// let C denote the same type, if any, as common_type_t<D1, D2>.
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using type = common_type<_Dp1, _Dp2>;
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};
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template<typename _Tp1, typename _Tp2>
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struct __common_type_impl<_Tp1, _Tp2, _Tp1, _Tp2>
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: private __do_common_type_impl
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{
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// Otherwise, if decay_t<decltype(false ? declval<D1>() : declval<D2>())>
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// denotes a valid type, let C denote that type.
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using type = decltype(_S_test<_Tp1, _Tp2>(0));
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};
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// If sizeof...(T) is two, ...
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template<typename _Tp1, typename _Tp2>
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struct common_type<_Tp1, _Tp2>
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: public __common_type_impl<_Tp1, _Tp2>::type
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{ };
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template<typename _Tp, typename _Up, typename... _Vp>
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struct common_type<_Tp, _Up, _Vp...>
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: public __expanded_common_type_wrapper<typename __member_type_wrapper<
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common_type<_Tp, _Up>>::type, _Vp...>::type
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template<typename...>
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struct __common_type_pack
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{ };
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template<typename, typename, typename = void>
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struct __common_type_fold;
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// If sizeof...(T) is greater than two, ...
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template<typename _Tp1, typename _Tp2, typename... _Rp>
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struct common_type<_Tp1, _Tp2, _Rp...>
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: public __common_type_fold<common_type<_Tp1, _Tp2>,
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__common_type_pack<_Rp...>>
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{ };
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// Let C denote the same type, if any, as common_type_t<T1, T2>.
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// If there is such a type C, type shall denote the same type, if any,
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// as common_type_t<C, R...>.
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template<typename _CTp, typename... _Rp>
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struct __common_type_fold<_CTp, __common_type_pack<_Rp...>,
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__void_t<typename _CTp::type>>
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: public common_type<typename _CTp::type, _Rp...>
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{ };
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// Otherwise, there shall be no member type.
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template<typename _CTp, typename _Rp>
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struct __common_type_fold<_CTp, _Rp, void>
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{ };
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template<typename _Tp, bool = is_enum<_Tp>::value>
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@ -2446,9 +2465,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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template<bool _Cond, typename _Tp = void>
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using __enable_if_t = typename enable_if<_Cond, _Tp>::type;
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// __void_t (std::void_t for C++11)
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template<typename...> using __void_t = void;
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#if __cplusplus >= 201703L || !defined(__STRICT_ANSI__) // c++17 or gnu++11
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#define __cpp_lib_void_t 201411
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/// A metafunction that always yields void, used for detecting valid types.
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@ -214,6 +214,7 @@ static_assert(is_type<std::common_type<void(&&)(), void(&)()>,
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static_assert(is_type<std::common_type<void(&&)(), void(&&)()>,
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void(*)()>(), "");
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static_assert(is_type<std::common_type<ImplicitTo<int>, int>, int>(), "");
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static_assert(is_type<std::common_type<const ImplicitTo<int>, int>, int>(), "");
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static_assert(is_type<std::common_type<ImplicitTo<int>, ImplicitTo<int>>,
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ImplicitTo<int>>(), "");
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static_assert(is_type<std::common_type<ImplicitTo<int>, int,
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@ -260,19 +261,22 @@ static_assert(is_type<std::common_type<volatile Ukn&&, volatile Ukn&&>,
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Ukn>(), "");
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static_assert(is_type<std::common_type<X1, X2>, RX12>(), "");
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static_assert(is_type<std::common_type<const X1, X2>, RX12>(), "");
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static_assert(is_type<std::common_type<X1&, const X2>, RX12>(), "");
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static_assert(is_type<std::common_type<const X1&, const X2&>, RX12>(), "");
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static_assert(is_type<std::common_type<X2, X1>, RX21>(), "");
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static_assert(is_type<std::common_type<X1, X2, X1>, Y1>(), "");
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static_assert(is_type<std::common_type<X2, X1, X1>, Y3>(), "");
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static_assert(is_type<std::common_type<X1, X1, X2>, RX12>(), "");
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static_assert(is_type<std::common_type<X1&, const X1, const X2&&>, RX12>(), "");
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static_assert(is_type<std::common_type<X1, X1, X2, X1>, Y1>(), "");
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static_assert(!has_type<std::common_type<>>(), "");
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static_assert(!has_type<std::common_type<int, S>>(), "");
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static_assert(!has_type<std::common_type<U, S>>(), "");
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static_assert(!has_type<std::common_type<U, U2>>(), "");
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static_assert(!has_type<std::common_type<const ImplicitTo<int>, int>>(), "");
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static_assert(!has_type<std::common_type<PrivateImplicitTo<int>, int>>(), "");
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static_assert(!has_type<std::common_type<const PrivateImplicitTo<int>,
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int>>(), "");
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@ -26,6 +26,6 @@ test01()
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// std::numeric_limits<int64_t>::max() == 9223372036854775807;
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auto h = 9223372036854775808h;
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// { dg-error "cannot be represented" "" { target *-*-* } 908 }
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// { dg-error "cannot be represented by duration" "" { target *-*-* } 0 }
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}
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// { dg-prune-output "in .constexpr. expansion" } // needed for -O0
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@ -29,4 +29,4 @@ void test01()
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test_type d; // { dg-error "required from here" }
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}
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// { dg-error "rep cannot be a duration" "" { target *-*-* } 316 }
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// { dg-error "rep cannot be a duration" "" { target *-*-* } 0 }
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||||
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@ -30,5 +30,5 @@ void test01()
|
|||
test_type d; // { dg-error "required from here" }
|
||||
}
|
||||
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||||
// { dg-error "must be a specialization of ratio" "" { target *-*-* } 317 }
|
||||
// { dg-error "must be a specialization of ratio" "" { target *-*-* } 0 }
|
||||
// { dg-prune-output "not a member" }
|
||||
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|||
|
|
@ -31,4 +31,4 @@ void test01()
|
|||
test_type d; // { dg-error "required from here" }
|
||||
}
|
||||
|
||||
// { dg-error "period must be positive" "" { target *-*-* } 319 }
|
||||
// { dg-error "period must be positive" "" { target *-*-* } 0 }
|
||||
|
|
|
|||
Loading…
Reference in New Issue