73e8e1ba8d
While it's not necessary to qualify calls to `declval` it makes error messages very crypric if the declaration isn't reachable anymore
For example:
```
/home/nikolask/llvm-projects/libcxx/build/include/c++/v1/__chrono/duration.h:53:66: error: no type named 'type' in 'std::common_type<long, long>'
typedef chrono::duration<typename common_type<_Rep1, _Rep2>::type,
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
/home/nikolask/llvm-projects/libcxx/build/include/c++/v1/__type_traits/common_type.h:107:14: note: in instantiation of template class 'std::common_type<std::chrono::duration<long, std::ratio<3600, 1>>, std::chrono::duration<long, std::ratio<3600, 1>>>' requested here
: public common_type<_Tp, _Tp> {};
^
/home/nikolask/llvm-projects/libcxx/build/include/c++/v1/__chrono/duration.h:279:58: note: in instantiation of template class 'std::common_type<std::chrono::duration<long, std::ratio<3600, 1>>>' requested here
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR typename common_type<duration>::type operator+() const {return typename common_type<duration>::type(*this);}
^
/home/nikolask/llvm-projects/libcxx/build/include/c++/v1/__chrono/duration.h:308:54: note: in instantiation of template class 'std::chrono::duration<long, std::ratio<3600, 1>>' requested here
typedef duration< int, ratio_multiply<ratio<24>, hours::period>> days;
^
/home/nikolask/llvm-projects/libcxx/build/include/c++/v1/__chrono/duration.h:280:81: error: no type named 'type' in 'std::common_type<std::chrono::duration<long, std::ratio<3600, 1>>>'
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR typename common_type<duration>::type operator-() const {return typename common_type<duration>::type(-__rep_);}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
/home/nikolask/llvm-projects/libcxx/build/include/c++/v1/__chrono/duration.h:308:54: note: in instantiation of template class 'std::chrono::duration<long, std::ratio<3600, 1>>' requested here
typedef duration< int, ratio_multiply<ratio<24>, hours::period>> days;
^
/home/nikolask/llvm-projects/libcxx/build/include/c++/v1/__chrono/duration.h:53:66: error: no type named 'type' in 'std::common_type<int, int>'
typedef chrono::duration<typename common_type<_Rep1, _Rep2>::type,
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
/home/nikolask/llvm-projects/libcxx/build/include/c++/v1/__type_traits/common_type.h:107:14: note: in instantiation of template class 'std::common_type<std::chrono::duration<int, std::ratio<86400, 1>>, std::chrono::duration<int, std::ratio<86400, 1>>>' requested here
: public common_type<_Tp, _Tp> {};
^
/home/nikolask/llvm-projects/libcxx/build/include/c++/v1/__chrono/duration.h:279:58: note: in instantiation of template class 'std::common_type<std::chrono::duration<int, std::ratio<86400, 1>>>' requested here
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR typename common_type<duration>::type operator+() const {return typename common_type<duration>::type(*this);}
^
/home/nikolask/llvm-projects/libcxx/build/include/c++/v1/__chrono/duration.h:309:55: note: in instantiation of template class 'std::chrono::duration<int, std::ratio<86400, 1>>' requested here
typedef duration< int, ratio_multiply<ratio<7>, days::period>> weeks;
^
19 similar errors omitted
```
changes with qualification added to:
```
While building module 'std' imported from /home/nikolask/llvm-projects/libcxx/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/common_type.pass.cpp:13:
In file included from <module-includes>:17:
In file included from /home/nikolask/llvm-projects/libcxx/build/include/c++/v1/math.h:309:
In file included from /home/nikolask/llvm-projects/libcxx/build/include/c++/v1/limits:107:
In file included from /home/nikolask/llvm-projects/libcxx/build/include/c++/v1/type_traits:432:
In file included from /home/nikolask/llvm-projects/libcxx/build/include/c++/v1/__type_traits/common_reference.h:13:
/home/nikolask/llvm-projects/libcxx/build/include/c++/v1/__type_traits/common_type.h:28:43: error: declaration of 'declval' must be imported from module 'std.utility.__utility.declval' before it is required
using __cond_type = decltype(false ? std::declval<_Tp>() : std::declval<_Up>());
^
/home/nikolask/llvm-projects/libcxx/build/include/c++/v1/__utility/declval.h:30:34: note: declaration here is not visible
decltype(std::__declval<_Tp>(0)) declval() _NOEXCEPT;
^
/home/nikolask/llvm-projects/libcxx/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/common_type.pass.cpp:13:10: fatal error: could not build module 'std'
#include <functional>
~~~~~~~~^
2 errors generated.
```
Reviewed By: ldionne, Mordante, #libc
Spies: libcxx-commits
Differential Revision: https://reviews.llvm.org/D130854
106 lines
3.0 KiB
C++
106 lines
3.0 KiB
C++
// -*- C++ -*-
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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___FUNCTIONAL_REFERENCE_WRAPPER_H
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#define _LIBCPP___FUNCTIONAL_REFERENCE_WRAPPER_H
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#include <__config>
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#include <__functional/invoke.h>
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#include <__functional/weak_result_type.h>
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#include <__memory/addressof.h>
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#include <__type_traits/enable_if.h>
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#include <__type_traits/remove_cvref.h>
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#include <__utility/declval.h>
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#include <__utility/forward.h>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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# pragma GCC system_header
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#endif
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_LIBCPP_BEGIN_NAMESPACE_STD
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template <class _Tp>
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class _LIBCPP_TEMPLATE_VIS reference_wrapper : public __weak_result_type<_Tp>
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{
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public:
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// types
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typedef _Tp type;
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private:
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type* __f_;
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static void __fun(_Tp&) _NOEXCEPT;
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static void __fun(_Tp&&) = delete;
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public:
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template <class _Up, class = __enable_if_t<!__is_same_uncvref<_Up, reference_wrapper>::value, decltype(__fun(std::declval<_Up>())) > >
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
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reference_wrapper(_Up&& __u) _NOEXCEPT_(noexcept(__fun(std::declval<_Up>()))) {
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type& __f = static_cast<_Up&&>(__u);
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__f_ = _VSTD::addressof(__f);
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}
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// access
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
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operator type&() const _NOEXCEPT {return *__f_;}
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
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type& get() const _NOEXCEPT {return *__f_;}
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// invoke
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template <class... _ArgTypes>
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
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typename __invoke_of<type&, _ArgTypes...>::type
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operator() (_ArgTypes&&... __args) const {
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return std::__invoke(get(), std::forward<_ArgTypes>(__args)...);
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}
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};
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#if _LIBCPP_STD_VER > 14
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template <class _Tp>
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reference_wrapper(_Tp&) -> reference_wrapper<_Tp>;
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#endif
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template <class _Tp>
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inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
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reference_wrapper<_Tp>
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ref(_Tp& __t) _NOEXCEPT
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{
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return reference_wrapper<_Tp>(__t);
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}
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template <class _Tp>
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inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
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reference_wrapper<_Tp>
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ref(reference_wrapper<_Tp> __t) _NOEXCEPT
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{
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return __t;
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}
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template <class _Tp>
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inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
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reference_wrapper<const _Tp>
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cref(const _Tp& __t) _NOEXCEPT
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{
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return reference_wrapper<const _Tp>(__t);
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}
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template <class _Tp>
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inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
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reference_wrapper<const _Tp>
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cref(reference_wrapper<_Tp> __t) _NOEXCEPT
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{
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return __t;
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}
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template <class _Tp> void ref(const _Tp&&) = delete;
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template <class _Tp> void cref(const _Tp&&) = delete;
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP___FUNCTIONAL_REFERENCE_WRAPPER_H
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