22.4.3.1 Construction [tuple.cnstr] C++N4910:2022 (535) p678.cpp

# はじめに(Introduction)

N4910  Working Draft, Standard for Programming Language C++

http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2022/n4910.pdf

n4910は、ISO/IEC JTC1 SC22 WG21の作業原案(Working Draft)です。
公式のISO/IEC 14882原本ではありません。
ISO/IEC JTC1 SC22 WG21では、可能な限り作業文書を公開し、幅広い意見を求めています。
一連の記事はコード断片をコンパイルできる形にする方法を検討してコンパイル、リンク、実行して、規格案の原文と処理系(g++, Clang++)との違いを確認し、技術内容を検討し、ISO/IEC JTC1 SC22 WG21にフィードバックするために用います。
また、CERT C++, MISRA C++等のコーディング標準のコード断片をコンパイルする際の参考にさせていただこうと考えています。CERT C++, MISRA C++が標準化の動きとの時間的なずれがあれば確認できれば幸いです。また、boostライブラリとの関連、Linux OS, TOPPERSカーネル、g++(GCC), clang++(LLVM）との関係も調査中です。
何か、抜け漏れ、耳より情報がありましたらおしらせくださると幸いです。

 <この項は書きかけです。順次追記します。>

## 背景(back ground)
C/C++でコンパイルエラーが出ると、途方にくれることがしばしばあります。
何回かに１回は、該当するエラーが検索できます。
ただ、条件が違っていて、そこでの修正方法では目的を達成しないこともしばしばです。いろいろな条件のコンパイルエラーとその対応方法について、広く記録することによって、いつか同じエラーに遭遇した時にやくに立つことを目指しています。

この半年の間で、三度、自分のネットでの記録に助けられたことがあります。
また過去に解決できなかった記録を１０種類以上、最近になって解決できたことがあります。それは、主に次の３つの情報に基づいています。

https://stackoverflow.com
https://cpprefjp.github.io
http://ja.cppreference.com/

また
https://researchmap.jp/joub9b3my-1797580/#_1797580
に記載したサイトのお世話になっています。

## 作業方針(sequence)
Clang++では-std=c++03, C++2bの2種類
g++では-std=c++03, c++2bの２種類
でコンパイルし、

１）コンパイルエラーを収集する。
２）コンパイルエラーをなくす方法を検討する。
コンパイルエラーになる例を示すだけが目的のコードは、コンパイルエラーをなくすのではなく、コンパイルエラーの種類を収集するだけにする。
文法を示すのが目的のコード場合に、コンパイルエラーをなくすのに手間がかかる場合は、順次作業します。
３）リンクエラーをなくす方法を検討する。
文法を示すのが目的のコード場合に、リンクエラーをなくすのに手間がかかる場合は、順次作業します。
４）意味のある出力を作る。
コンパイル、リンクが通っても、意味のある出力を示そうとすると、コンパイル・リンクエラーが出て収拾できそうにない場合がある。順次作業します。

１）だけのものから４）まで進んだものと色々ある状態です。一歩でも前に進むご助言をお待ちしています。「検討事項」の欄に現状を記録するようにしています。

### C++N4910:2022 Standard Working Draft on ISO/IEC 14882(0) sample code compile list  

https://qiita.com/kaizen_nagoya/items/fc957ddddd402004bb91

### C++N4741, 2018 Standard Working Draft on ISO/IEC 14882 sample code compile list
https://qiita.com/kaizen_nagoya/items/3294c014044550896010

### C++N4606, 2016符号断片編纂一覧(example code compile list)
C++N4606, 2016 Working Draft 2016, ISO/IEC 14882, C++ standard(1) Example code compile list
https://qiita.com/kaizen_nagoya/items/df5d62c35bd6ed1c3d43/

### C++N3242, 2011 sample code compile list on clang++ and g++
https://qiita.com/kaizen_nagoya/items/685b5c1a2c17c1bf1318

## 編纂器(Compiler)
### clang++ --version
> Debian clang version 14.0.5-++20220610033153+c12386ae247c-1~exp1~20220610153237.151
Target: x86_64-pc-linux-gnu, Thread model: posix, InstalledDir: /usr/bin

### g++- --version
> g++ (GCC) 12.1.0  Copyright (C) 2022 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

#  22.4.3.1 Construction [tuple.cnstr] C++N4910:2022 (535) p678.cpp

## 算譜(source code)

```c++:p678.cpp
// C++N4910 Committee Draft, Standard for Programming Language C++
// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2022/n4910.pdf
const char * n4910 = " 22.4.3.1 Construction [tuple.cnstr] C++N4910:2022 (535) p678.cpp";
// Debian clang version 14.0.5-++20220610033153+c12386ae247c-
// g++ (GCC) 12.1.0 Copyright (C) 2022 Free Software Foundation, Inc.
// Edited by Dr. OGAWA Kiyoshi. Compile procedure and results record.
// C++N4910:2022 Standard Working Draft on ISO/IEC 14882(0) sample code compile list
// https://qiita.com/kaizen_nagoya/items/fc957ddddd402004bb91

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cassert>
#include <coroutine>
#include <vector>
#include <complex>
#include <map>
#include <atomic>
#include <unordered_map>
#include <memory>
#include <typeinfo>

using namespace std;

// Example 1
constexpr explicit(see below) tuple();
// Constraints: is_default_constructible_v<Ti> is true for all i.
// Effects: Value-initializes each element.
// Remarks: The expression inside explicit evaluates to true if and only if Ti is not copy-list-initializable from an empty list for at least one i.
// [Note 1: This behavior can be implemented with a trait that checks whether a const Ti& can be initialized with {}.
constexpr explicit(see below) tuple(const Types&...);
// Constraints: sizeof...(Types) ≥ 1 and is_copy_constructible_v<Ti> is true for all i. Effects: Initializes each element with the value of the corresponding parameter.
// Remarks: The expression inside explicit is equivalent to:
!conjunction_v<is_convertible<const Types&, Types>...>
template<class... UTypes> constexpr explicit(see_below) tuple(UTypes&&... u);
// Let disambiguating-constraint be:
// — negation<is_same<remove_cvref_t<U0>, tuple>> if sizeof...(Types) is 1;
// — otherwise,
bool_constant<!is_same_v<remove_cvref_t<U0>, allocator_arg_t> || is_- same_v<remove_cvref_t<T0>, allocator_arg_t>>
// if sizeof...(Types) is 2 or 3;
// — otherwise, true_type.
// Constraints:
// — sizeof...(Types) equals sizeof...(UTypes),
// — sizeof...(Types) ≥ 1, and
// — conjunction_v<disambiguating-constraint , is_constructible<Types, UTypes>...> is true.
// Effects: Initializes the elements in the tuple with the corresponding value in std::forward<UTypes>(u). Remarks: The expression inside explicit is equivalent to:
        !conjunction_v<is_convertible<UTypes, Types>...>
// This constructor is defined as deleted if
        (reference_constructs_from_temporary_v<Types, UTypes\&\&> || ...)
// is true.
        template<class U1, class U2> constexpr explicit(see_below) tuple(pair<U1, U2>& u);
template<class U1, class U2> constexpr explicit(see_below) tuple(const pair<U1, U2>& u);
template<class U1, class U2> constexpr explicit(see_below) tuple(pair<U1, U2>&& u);
template<class U1, class U2> constexpr explicit(see_below) tuple(const pair<U1, U2>&& u);
// Let FWD (u) be static_cast<decltype(u)>(u). Constraints:
// — sizeof...(Types) is 2,
// — is_constructible_v<T0, decltype(get<0>(FWD (u)))> is true, and
// — is_constructible_v<T1, decltype(get<1>(FWD (u)))> is true.
// Effects: Initializes the first element with get<0>(FWD (u)) and the second element with get<1>(FWD ( u)).
// Remarks: The expression inside explicit is equivalent to: !is_convertible_v<decltype(get<0>(FWD(u))), T0> ||
!is_convertible_v<decltype(get<1>(FWD(u))), T1>
// The constructor is defined as deleted if
tuple(const tuple& u) = default;
// Mandates: is_copy_constructible_v<Ti> is true for all i.
// Effects: Initializes each element of *this with the corresponding element of u.
tuple(tuple&& u) = default;
// Constraints: is_move_constructible_v<Ti> is true for all i.
// Effects: For all i, initializes the ith element of *this with std::forward<Ti>(get<i>(u)).
template<class... UTypes> constexpr explicit(see_below) tuple(tuple<UTypes...>& u);
template<class... UTypes> constexpr explicit(see_below) tuple(const tuple<UTypes...>& u);
template<class... UTypes> constexpr explicit(see_below) tuple(tuple<UTypes...>&& u);
template<class... UTypes> constexpr explicit(see_below) tuple(const tuple<UTypes...>&& u);
// Let I be the pack 0, 1, ..., (sizeof...(Types) - 1). Let FWD (u) be static_cast<decltype(u)>(u).
// Constraints:
// — sizeof...(Types) equals sizeof...(UTypes), and
// — (is_constructible_v<Types, decltype(get<I>(FWD (u)))> && ...) is true, and
// — either sizeof...(Types) is not 1, or (when Types... expands to T and UTypes... expands to U) is_convertible_v<decltype(u), T>, is_constructible_v<T, decltype(u)>, and is_- same_v<T, U> are all false.
// Effects: For all i, initializes the ith element of *this with get<i>(FWD (u)).
// Remarks: The expression inside explicit is equivalent to:
!(is_convertible_v<decltype(get<I>(FWD(u))), Types> && ...)
// The constructor is defined as deleted if
(reference_constructs_from_temporary_v<Types, decltype(get<I>(FWD(u)))> || ...)
// is true.
int main() {
    cout  <<  n4910 << endl;
    return EXIT_SUCCESS;
}
```

## 編纂・実行結果(compile and go)

```ubuntu:bash
$ clang++ p678.cpp -std=03 -o p678l -I. -Wall
In file included from p678.cpp:19:
In file included from /usr/bin/../lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/atomic:38:
/usr/bin/../lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/bits/c++0x_warning.h:32:2: error: This file requires compiler and library support for the ISO C++ 2011 standard. This support must be enabled with the -std=c++11 or -std=gnu++11 compiler options.
#error This file requires compiler and library support \
 ^
p678.cpp:27:1: error: unknown type name 'constexpr'
constexpr explicit(see below) tuple();
^
p678.cpp:27:19: warning: explicit(bool) is a C++20 extension [-Wc++20-extensions]
constexpr explicit(see below) tuple();
                  ^
p678.cpp:27:20: error: use of undeclared identifier 'see'
constexpr explicit(see below) tuple();
                   ^
p678.cpp:32:1: error: unknown type name 'constexpr'
constexpr explicit(see below) tuple(const Types&...);
^
p678.cpp:32:19: warning: explicit(bool) is a C++20 extension [-Wc++20-extensions]
constexpr explicit(see below) tuple(const Types&...);
                  ^
p678.cpp:32:20: error: use of undeclared identifier 'see'
constexpr explicit(see below) tuple(const Types&...);
                   ^
p678.cpp:32:43: error: unknown type name 'Types'
constexpr explicit(see below) tuple(const Types&...);
                                          ^
p678.cpp:35:8: error: expected unqualified-id
       !conjunction_v<is_convertible<const Types&, Types>...>
       ^
p678.cpp:40:41: error: use of undeclared identifier 'U0'
bool_constant<!is_same_v<remove_cvref_t<U0>, allocator_arg_t> || is_- same_v<remove_cvref_t<T0>, allocator_arg_t>> 
                                        ^
p678.cpp:40:93: error: use of undeclared identifier 'T0'
bool_constant<!is_same_v<remove_cvref_t<U0>, allocator_arg_t> || is_- same_v<remove_cvref_t<T0>, allocator_arg_t>> 
                                                                                            ^
p678.cpp:40:66: error: use of undeclared identifier 'is_'
bool_constant<!is_same_v<remove_cvref_t<U0>, allocator_arg_t> || is_- same_v<remove_cvref_t<T0>, allocator_arg_t>> 
                                                                 ^
p678.cpp:50:42: error: use of undeclared identifier 'Types'
  (reference_constructs_from_temporary_v<Types, UTypes\&\&> || ...)
                                         ^
p678.cpp:50:61: error: expected ')'
  (reference_constructs_from_temporary_v<Types, UTypes\&\&> || ...)
                                                            ^
p678.cpp:50:3: note: to match this '('
  (reference_constructs_from_temporary_v<Types, UTypes\&\&> || ...)
  ^
p678.cpp:53:30: error: unknown type name 'constexpr'
template<class U1, class U2> constexpr explicit(see_below) tuple(const pair<U1, U2>& u); 
                             ^
p678.cpp:53:48: warning: explicit(bool) is a C++20 extension [-Wc++20-extensions]
template<class U1, class U2> constexpr explicit(see_below) tuple(const pair<U1, U2>& u); 
                                               ^
p678.cpp:53:49: error: use of undeclared identifier 'see_below'
template<class U1, class U2> constexpr explicit(see_below) tuple(const pair<U1, U2>& u); 
                                                ^
p678.cpp:54:30: error: unknown type name 'constexpr'
template<class U1, class U2> constexpr explicit(see_below) tuple(pair<U1, U2>&& u); 
                             ^
p678.cpp:54:48: warning: explicit(bool) is a C++20 extension [-Wc++20-extensions]
template<class U1, class U2> constexpr explicit(see_below) tuple(pair<U1, U2>&& u); 
                                               ^
p678.cpp:54:49: error: use of undeclared identifier 'see_below'
template<class U1, class U2> constexpr explicit(see_below) tuple(pair<U1, U2>&& u); 
                                                ^
p678.cpp:54:78: warning: rvalue references are a C++11 extension [-Wc++11-extensions]
template<class U1, class U2> constexpr explicit(see_below) tuple(pair<U1, U2>&& u); 
                                                                             ^
p678.cpp:55:30: error: unknown type name 'constexpr'
template<class U1, class U2> constexpr explicit(see_below) tuple(const pair<U1, U2>&& u);
                             ^
p678.cpp:55:48: warning: explicit(bool) is a C++20 extension [-Wc++20-extensions]
template<class U1, class U2> constexpr explicit(see_below) tuple(const pair<U1, U2>&& u);
                                               ^
p678.cpp:55:49: error: use of undeclared identifier 'see_below'
template<class U1, class U2> constexpr explicit(see_below) tuple(const pair<U1, U2>&& u);
                                                ^
p678.cpp:55:84: warning: rvalue references are a C++11 extension [-Wc++11-extensions]
template<class U1, class U2> constexpr explicit(see_below) tuple(const pair<U1, U2>&& u);
                                                                                   ^
p678.cpp:62:1: error: expected unqualified-id
!is_convertible_v<decltype(get<1>(FWD(u))), T1> 
^
fatal error: too many errors emitted, stopping now [-ferror-limit=]
7 warnings and 20 errors generated.
$ clang++ p678.cpp -std=2b -o p678l -I. -Wall
p678.cpp:27:20: error: use of undeclared identifier 'see'
constexpr explicit(see below) tuple();
                   ^
p678.cpp:27:31: error: deduction guide must be declared in the same scope as template 'std::tuple'
constexpr explicit(see below) tuple();
                              ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/tuple:516:11: note: template is declared here
    class tuple : public _Tuple_impl<0, _Elements...>
          ^
p678.cpp:27:31: error: deduction guide cannot be declared 'constexpr'
constexpr explicit(see below) tuple();
~~~~~~~~~                     ^
p678.cpp:27:31: error: deduction guide declaration without trailing return type
p678.cpp:32:20: error: use of undeclared identifier 'see'
constexpr explicit(see below) tuple(const Types&...);
                   ^
p678.cpp:32:43: error: unknown type name 'Types'
constexpr explicit(see below) tuple(const Types&...);
                                          ^
p678.cpp:32:31: error: deduction guide must be declared in the same scope as template 'std::tuple'
constexpr explicit(see below) tuple(const Types&...);
                              ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/tuple:516:11: note: template is declared here
    class tuple : public _Tuple_impl<0, _Elements...>
          ^
p678.cpp:32:31: error: deduction guide cannot be declared 'constexpr'
constexpr explicit(see below) tuple(const Types&...);
~~~~~~~~~                     ^
p678.cpp:32:31: error: deduction guide declaration without trailing return type
p678.cpp:35:8: error: expected unqualified-id
       !conjunction_v<is_convertible<const Types&, Types>...>
       ^
p678.cpp:40:41: error: use of undeclared identifier 'U0'
bool_constant<!is_same_v<remove_cvref_t<U0>, allocator_arg_t> || is_- same_v<remove_cvref_t<T0>, allocator_arg_t>> 
                                        ^
p678.cpp:40:93: error: use of undeclared identifier 'T0'
bool_constant<!is_same_v<remove_cvref_t<U0>, allocator_arg_t> || is_- same_v<remove_cvref_t<T0>, allocator_arg_t>> 
                                                                                            ^
p678.cpp:40:66: error: use of undeclared identifier 'is_'
bool_constant<!is_same_v<remove_cvref_t<U0>, allocator_arg_t> || is_- same_v<remove_cvref_t<T0>, allocator_arg_t>> 
                                                                 ^
p678.cpp:48:3: error: expected unqualified-id
  !conjunction_v<is_convertible<UTypes, Types>...>
  ^
p678.cpp:53:49: error: use of undeclared identifier 'see_below'
template<class U1, class U2> constexpr explicit(see_below) tuple(const pair<U1, U2>& u); 
                                                ^
p678.cpp:53:60: error: deduction guide must be declared in the same scope as template 'std::tuple'
template<class U1, class U2> constexpr explicit(see_below) tuple(const pair<U1, U2>& u); 
                                                           ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/tuple:516:11: note: template is declared here
    class tuple : public _Tuple_impl<0, _Elements...>
          ^
p678.cpp:53:60: error: deduction guide cannot be declared 'constexpr'
template<class U1, class U2> constexpr explicit(see_below) tuple(const pair<U1, U2>& u); 
                             ~~~~~~~~~                     ^
p678.cpp:53:60: error: deduction guide declaration without trailing return type
p678.cpp:54:49: error: use of undeclared identifier 'see_below'
template<class U1, class U2> constexpr explicit(see_below) tuple(pair<U1, U2>&& u); 
                                                ^
fatal error: too many errors emitted, stopping now [-ferror-limit=]
20 errors generated.

$ g++ p678.cpp -std=03 -o p678g -I. -Wall
In file included from /usr/local/include/c++/12.1.0/atomic:38,
                 from p678.cpp:19:
/usr/local/include/c++/12.1.0/bits/c++0x_warning.h:32:2: error: #error This file requires compiler and library support for the ISO C++ 2011 standard. This support must be enabled with the -std=c++11 or -std=gnu++11 compiler options.
   32 | #error This file requires compiler and library support \
      |  ^~~~~
p678.cpp:27:1: warning: identifier 'constexpr' is a keyword in C++11 [-Wc++11-compat]
   27 | constexpr explicit(see below) tuple();
      | ^~~~~~~~~
p678.cpp:50:55: error: stray '\' in program
   50 |   (reference_constructs_from_temporary_v<Types, UTypes\&\&> || ...)
      |                                                       ^
p678.cpp:50:57: error: stray '\' in program
   50 |   (reference_constructs_from_temporary_v<Types, UTypes\&\&> || ...)
      |                                                         ^
p678.cpp:62:19: warning: identifier 'decltype' is a keyword in C++11 [-Wc++11-compat]
   62 | !is_convertible_v<decltype(get<1>(FWD(u))), T1>
      |                   ^~~~~~~~
p678.cpp:27:1: error: 'constexpr' does not name a type
   27 | constexpr explicit(see below) tuple();
      | ^~~~~~~~~
p678.cpp:27:1: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p678.cpp:32:1: error: 'constexpr' does not name a type
   32 | constexpr explicit(see below) tuple(const Types&...);
      | ^~~~~~~~~
p678.cpp:32:1: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p678.cpp:35:8: error: expected unqualified-id before '!' token
   35 |        !conjunction_v<is_convertible<const Types&, Types>...>
      |        ^
p678.cpp:40:1: error: 'bool_constant' does not name a type
   40 | bool_constant<!is_same_v<remove_cvref_t<U0>, allocator_arg_t> || is_- same_v<remove_cvref_t<T0>, allocator_arg_t>>
      | ^~~~~~~~~~~~~
p678.cpp:53:30: error: 'constexpr' does not name a type
   53 | template<class U1, class U2> constexpr explicit(see_below) tuple(const pair<U1, U2>& u);
      |                              ^~~~~~~~~
p678.cpp:53:30: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p678.cpp:54:30: error: 'constexpr' does not name a type
   54 | template<class U1, class U2> constexpr explicit(see_below) tuple(pair<U1, U2>&& u);
      |                              ^~~~~~~~~
p678.cpp:54:30: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p678.cpp:55:30: error: 'constexpr' does not name a type
   55 | template<class U1, class U2> constexpr explicit(see_below) tuple(const pair<U1, U2>&& u);
      |                              ^~~~~~~~~
p678.cpp:55:30: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p678.cpp:62:1: error: expected unqualified-id before '!' token
   62 | !is_convertible_v<decltype(get<1>(FWD(u))), T1>
      | ^
p678.cpp:67:6: error: expected constructor, destructor, or type conversion before '(' token
   67 | tuple(tuple&& u) = default;
      |      ^
p678.cpp:70:15: warning: variadic templates only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
   70 | template<class... UTypes> constexpr explicit(see_below) tuple(tuple<UTypes...>& u);
      |               ^~~
p678.cpp:70:27: error: 'constexpr' does not name a type
   70 | template<class... UTypes> constexpr explicit(see_below) tuple(tuple<UTypes...>& u);
      |                           ^~~~~~~~~
p678.cpp:70:27: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p678.cpp:71:15: warning: variadic templates only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
   71 | template<class... UTypes> constexpr explicit(see_below) tuple(const tuple<UTypes...>& u);
      |               ^~~
p678.cpp:71:27: error: 'constexpr' does not name a type
   71 | template<class... UTypes> constexpr explicit(see_below) tuple(const tuple<UTypes...>& u);
      |                           ^~~~~~~~~
p678.cpp:71:27: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p678.cpp:72:15: warning: variadic templates only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
   72 | template<class... UTypes> constexpr explicit(see_below) tuple(tuple<UTypes...>&& u);
      |               ^~~
p678.cpp:72:27: error: 'constexpr' does not name a type
   72 | template<class... UTypes> constexpr explicit(see_below) tuple(tuple<UTypes...>&& u);
      |                           ^~~~~~~~~
p678.cpp:72:27: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p678.cpp:73:15: warning: variadic templates only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
   73 | template<class... UTypes> constexpr explicit(see_below) tuple(const tuple<UTypes...>&& u);
      |               ^~~
p678.cpp:73:27: error: 'constexpr' does not name a type
   73 | template<class... UTypes> constexpr explicit(see_below) tuple(const tuple<UTypes...>&& u);
      |                           ^~~~~~~~~
p678.cpp:73:27: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p678.cpp:81:1: error: expected unqualified-id before '!' token
   81 | !(is_convertible_v<decltype(get<I>(FWD(u))), Types> && ...)
      | ^

$ g++ p678.cpp -std=2b -o p678g -I. -Wall
p678.cpp:50:55: error: stray '\' in program
   50 |   (reference_constructs_from_temporary_v<Types, UTypes\&\&> || ...)
      |                                                       ^
p678.cpp:50:57: error: stray '\' in program
   50 |   (reference_constructs_from_temporary_v<Types, UTypes\&\&> || ...)
      |                                                         ^
p678.cpp:27:20: error: 'see' was not declared in this scope
   27 | constexpr explicit(see below) tuple();
      |                    ^~~
p678.cpp:27:23: error: expected ')' before 'below'
   27 | constexpr explicit(see below) tuple();
      |                   ~   ^~~~~~
      |                       )
p678.cpp:27:24: error: 'below' does not name a type
   27 | constexpr explicit(see below) tuple();
      |                        ^~~~~
p678.cpp:32:20: error: 'see' was not declared in this scope
   32 | constexpr explicit(see below) tuple(const Types&...);
      |                    ^~~
p678.cpp:32:23: error: expected ')' before 'below'
   32 | constexpr explicit(see below) tuple(const Types&...);
      |                   ~   ^~~~~~
      |                       )
p678.cpp:32:24: error: 'below' does not name a type
   32 | constexpr explicit(see below) tuple(const Types&...);
      |                        ^~~~~
p678.cpp:35:8: error: expected unqualified-id before '!' token
   35 |        !conjunction_v<is_convertible<const Types&, Types>...>
      |        ^
p678.cpp:40:41: error: 'U0' was not declared in this scope; did you mean 'y0'?
   40 | bool_constant<!is_same_v<remove_cvref_t<U0>, allocator_arg_t> || is_- same_v<remove_cvref_t<T0>, allocator_arg_t>>
      |                                         ^~
      |                                         y0
p678.cpp:40:43: error: template argument 1 is invalid
   40 | bool_constant<!is_same_v<remove_cvref_t<U0>, allocator_arg_t> || is_- same_v<remove_cvref_t<T0>, allocator_arg_t>>
      |                                           ^
p678.cpp:40:16: error: template argument 1 is invalid
   40 | bool_constant<!is_same_v<remove_cvref_t<U0>, allocator_arg_t> || is_- same_v<remove_cvref_t<T0>, allocator_arg_t>>
      |                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
p678.cpp:40:66: error: 'is_' was not declared in this scope
   40 | bool_constant<!is_same_v<remove_cvref_t<U0>, allocator_arg_t> || is_- same_v<remove_cvref_t<T0>, allocator_arg_t>>
      |                                                                  ^~~
p678.cpp:40:93: error: 'T0' was not declared in this scope; did you mean 'y0'?
   40 | stant<!is_same_v<remove_cvref_t<U0>, allocator_arg_t> || is_- same_v<remove_cvref_t<T0>, allocator_arg_t>>
      |                                                                                     ^~
      |                                                                                     y0
p678.cpp:40:95: error: template argument 1 is invalid
   40 | ant<!is_same_v<remove_cvref_t<U0>, allocator_arg_t> || is_- same_v<remove_cvref_t<T0>, allocator_arg_t>>
      |                                                                                     ^

p678.cpp:40:71: error: 'same_v' was not declared in this scope
   40 | bool_constant<!is_same_v<remove_cvref_t<U0>, allocator_arg_t> || is_- same_v<remove_cvref_t<T0>, allocator_arg_t>>
      |                                                                       ^~~~~~
p678.cpp:40:113: error: wrong number of template arguments (2, should be 1)
   40 | ame_v<remove_cvref_t<U0>, allocator_arg_t> || is_- same_v<remove_cvref_t<T0>, allocator_arg_t>>
      |                                                                                              ^~

In file included from /usr/local/include/c++/12.1.0/bits/move.h:57,
                 from /usr/local/include/c++/12.1.0/bits/exception_ptr.h:43,
                 from /usr/local/include/c++/12.1.0/exception:168,
                 from /usr/local/include/c++/12.1.0/ios:39,
                 from /usr/local/include/c++/12.1.0/ostream:38,
                 from /usr/local/include/c++/12.1.0/iostream:39,
                 from p678.cpp:10:
/usr/local/include/c++/12.1.0/type_traits:98:11: note: provided for 'template<bool __v> using bool_constant = std::integral_constant<bool, __v>'
   98 |     using bool_constant = integral_constant<bool, __v>;
      |           ^~~~~~~~~~~~~
p678.cpp:48:3: error: expected unqualified-id before '!' token
   48 |   !conjunction_v<is_convertible<UTypes, Types>...>
      |   ^
p678.cpp:53:49: error: 'see_below' was not declared in this scope
   53 | template<class U1, class U2> constexpr explicit(see_below) tuple(const pair<U1, U2>& u);
      |                                                 ^~~~~~~~~
p678.cpp:53:30: error: 'decl-specifier' in declaration of deduction guide
   53 | template<class U1, class U2> constexpr explicit(see_below) tuple(const pair<U1, U2>& u);
      |                              ^~~~~~~~~
p678.cpp:53:60: error: deduction guide for 'std::tuple< <template-parameter-1-1> >' must have trailing return type
   53 | template<class U1, class U2> constexpr explicit(see_below) tuple(const pair<U1, U2>& u);
      |                                                            ^~~~~
In file included from /usr/local/include/c++/12.1.0/bits/stl_algobase.h:64,
                 from /usr/local/include/c++/12.1.0/string:50,
                 from /usr/local/include/c++/12.1.0/bits/locale_classes.h:40,
                 from /usr/local/include/c++/12.1.0/bits/ios_base.h:41,
                 from /usr/local/include/c++/12.1.0/ios:42:
/usr/local/include/c++/12.1.0/bits/stl_pair.h:90:11: note: 'template<class ...> class std::tuple' declared here
   90 |     class tuple;
      |           ^~~~~
p678.cpp:54:49: error: 'see_below' was not declared in this scope
   54 | template<class U1, class U2> constexpr explicit(see_below) tuple(pair<U1, U2>&& u);
      |                                                 ^~~~~~~~~
p678.cpp:54:30: error: 'decl-specifier' in declaration of deduction guide
   54 | template<class U1, class U2> constexpr explicit(see_below) tuple(pair<U1, U2>&& u);
      |                              ^~~~~~~~~
p678.cpp:54:60: error: deduction guide for 'std::tuple< <template-parameter-1-1> >' must have trailing return type
   54 | template<class U1, class U2> constexpr explicit(see_below) tuple(pair<U1, U2>&& u);
      |                                                            ^~~~~
/usr/local/include/c++/12.1.0/bits/stl_pair.h:90:11: note: 'template<class ...> class std::tuple' declared here
   90 |     class tuple;
      |           ^~~~~
p678.cpp:55:49: error: 'see_below' was not declared in this scope
   55 | template<class U1, class U2> constexpr explicit(see_below) tuple(const pair<U1, U2>&& u);
      |                                                 ^~~~~~~~~
p678.cpp:55:30: error: 'decl-specifier' in declaration of deduction guide
   55 | template<class U1, class U2> constexpr explicit(see_below) tuple(const pair<U1, U2>&& u);
      |                              ^~~~~~~~~
p678.cpp:55:60: error: deduction guide for 'std::tuple< <template-parameter-1-1> >' must have trailing return type
   55 | template<class U1, class U2> constexpr explicit(see_below) tuple(const pair<U1, U2>&& u);
      |                                                            ^~~~~
/usr/local/include/c++/12.1.0/bits/stl_pair.h:90:11: note: 'template<class ...> class std::tuple' declared here
   90 |     class tuple;
      |           ^~~~~
p678.cpp:62:1: error: expected unqualified-id before '!' token
   62 | !is_convertible_v<decltype(get<1>(FWD(u))), T1>
      | ^
p678.cpp:67:7: error: template placeholder type 'tuple<...auto...>' must be followed by a simple declarator-id
   67 | tuple(tuple&& u) = default;
      |       ^~~~~
/usr/local/include/c++/12.1.0/bits/stl_pair.h:90:11: note: 'template<class ...> class std::tuple' declared here
   90 |     class tuple;
      |           ^~~~~
p678.cpp:67:1: error: deduction guide for 'std::tuple< <template-parameter-1-1> >' must have trailing return type
   67 | tuple(tuple&& u) = default;
      | ^~~~~
/usr/local/include/c++/12.1.0/bits/stl_pair.h:90:11: note: 'template<class ...> class std::tuple' declared here
   90 |     class tuple;
      |           ^~~~~
p678.cpp:70:46: error: 'see_below' was not declared in this scope
   70 | template<class... UTypes> constexpr explicit(see_below) tuple(tuple<UTypes...>& u);
      |                                              ^~~~~~~~~
p678.cpp:70:27: error: 'decl-specifier' in declaration of deduction guide
   70 | template<class... UTypes> constexpr explicit(see_below) tuple(tuple<UTypes...>& u);
      |                           ^~~~~~~~~
p678.cpp:70:57: error: deduction guide for 'std::tuple< <template-parameter-1-1> >' must have trailing return type
   70 | template<class... UTypes> constexpr explicit(see_below) tuple(tuple<UTypes...>& u);
      |                                                         ^~~~~
/usr/local/include/c++/12.1.0/bits/stl_pair.h:90:11: note: 'template<class ...> class std::tuple' declared here
   90 |     class tuple;
      |           ^~~~~
p678.cpp:71:46: error: 'see_below' was not declared in this scope
   71 | template<class... UTypes> constexpr explicit(see_below) tuple(const tuple<UTypes...>& u);
      |                                              ^~~~~~~~~
p678.cpp:71:27: error: 'decl-specifier' in declaration of deduction guide
   71 | template<class... UTypes> constexpr explicit(see_below) tuple(const tuple<UTypes...>& u);
      |                           ^~~~~~~~~
p678.cpp:71:57: error: deduction guide for 'std::tuple< <template-parameter-1-1> >' must have trailing return type
   71 | template<class... UTypes> constexpr explicit(see_below) tuple(const tuple<UTypes...>& u);
      |                                                         ^~~~~
/usr/local/include/c++/12.1.0/bits/stl_pair.h:90:11: note: 'template<class ...> class std::tuple' declared here
   90 |     class tuple;
      |           ^~~~~
p678.cpp:72:46: error: 'see_below' was not declared in this scope
   72 | template<class... UTypes> constexpr explicit(see_below) tuple(tuple<UTypes...>&& u);
      |                                              ^~~~~~~~~
p678.cpp:72:27: error: 'decl-specifier' in declaration of deduction guide
   72 | template<class... UTypes> constexpr explicit(see_below) tuple(tuple<UTypes...>&& u);
      |                           ^~~~~~~~~
p678.cpp:72:57: error: deduction guide for 'std::tuple< <template-parameter-1-1> >' must have trailing return type
   72 | template<class... UTypes> constexpr explicit(see_below) tuple(tuple<UTypes...>&& u);
      |                                                         ^~~~~
/usr/local/include/c++/12.1.0/bits/stl_pair.h:90:11: note: 'template<class ...> class std::tuple' declared here
   90 |     class tuple;
      |           ^~~~~
p678.cpp:73:46: error: 'see_below' was not declared in this scope
   73 | template<class... UTypes> constexpr explicit(see_below) tuple(const tuple<UTypes...>&& u);
      |                                              ^~~~~~~~~
p678.cpp:73:27: error: 'decl-specifier' in declaration of deduction guide
   73 | template<class... UTypes> constexpr explicit(see_below) tuple(const tuple<UTypes...>&& u);
      |                           ^~~~~~~~~
p678.cpp:73:57: error: deduction guide for 'std::tuple< <template-parameter-1-1> >' must have trailing return type
   73 | template<class... UTypes> constexpr explicit(see_below) tuple(const tuple<UTypes...>&& u);
      |                                                         ^~~~~
/usr/local/include/c++/12.1.0/bits/stl_pair.h:90:11: note: 'template<class ...> class std::tuple' declared here
   90 |     class tuple;
      |           ^~~~~
p678.cpp:81:1: error: expected unqualified-id before '!' token
   81 | !(is_convertible_v<decltype(get<I>(FWD(u))), Types> && ...)
      | ^

```

## 検討事項(agenda)
コンパイルエラーを取るか、コンパイルエラーの理由を解説する。

<!-- リンクエラーの解説をする。clang++とg++の比較。意味のある出力。
コンパイルエラーを取るか、コンパイルエラーの理由を解説する。-->

# 参考資料(reference)

cpprefjp - C++日本語リファレンス

https://cpprefjp.github.io/

コンパイラの実装状況

https://cpprefjp.github.io/implementation-status.html


typedef は C++11 ではオワコン

https://qiita.com/Linda_pp/items/44a67c64c14cba00eef1

C99からC++14を駆け抜けるC++講座

https://qiita.com/yumetodo/items/e49a673afd9a3ecb81a8


@kazuo_reve 私が効果を確認した「小川メソッド」

https://qiita.com/kazuo_reve/items/a3ea1d9171deeccc04da

## 自己参照(self reference)

ockerにclang

https://qiita.com/kaizen_nagoya/items/8829ffeee397eda50e80

docker gnu(gcc/g++) and llvm(clang/clang++)

https://qiita.com/drafts/059874ea39c4de64c0f7

コンパイル用shell script C版(clangとgcc)とC++版(clang++とg++)

https://qiita.com/kaizen_nagoya/items/74220c0577a512c2d7da

C++N4910:2022 tag follower 200人超えました。ありがとうございます。

https://qiita.com/kaizen_nagoya/items/a63fb96d351ac5c16ff7

C++N4910:2022 tag follower 200人超えました。ありがとうございます。

https://qiita.com/kaizen_nagoya/items/a63fb96d351ac5c16ff7

コピペコンパイルエラーあるある

https://qiita.com/kaizen_nagoya/items/29c832de9d762aed2761

C++ Error Message Collection(1)does not name a type, 11 articles

https://qiita.com/kaizen_nagoya/items/acb9f1a9b5aad6df06bd

dockerにclang

https://qiita.com/kaizen_nagoya/items/8829ffeee397eda50e80

docker gnu(gcc/g++) and llvm(clang/clang++)

https://qiita.com/drafts/059874ea39c4de64c0f7

コンパイル用shell script C版(clangとgcc)とC++版(clang++とg++)

https://qiita.com/kaizen_nagoya/items/74220c0577a512c2d7da

Compare the contents of C++N4910:2022, C++N4741:2018 and C++N4606:2015

https://qiita.com/kaizen_nagoya/items/483246d40f98abff7ded

C++ sample list

https://qiita.com/kaizen_nagoya/items/54ad75b73825b7c04f86

clang++, g++コンパイルエラー方針の違いの例

https://qiita.com/kaizen_nagoya/items/ea6e5009fe126d270a82

astyle 使ってみた

https://qiita.com/kaizen_nagoya/items/3c9a87a781d53a1a23f3

C++N4606 Working Draft 2016, ISO/IEC 14882, C++ standardのコード断片をコンパイルするためにしていること
https://qiita.com/kaizen_nagoya/items/a8d7ee2f2e29e76c19c1

コンパイル用shell script C版(clangとgcc)とC++版(clang++とg++)
https://qiita.com/kaizen_nagoya/items/74220c0577a512c2d7da

Clang/Clang++(LLVM) gcc/g++(GNU) コンパイラ警告等比較
https://qiita.com/kaizen_nagoya/items/9a82b958cc3aeef0403f

C++2003とC++2017でコンパイルエラーになるならない事例集
https://qiita.com/kaizen_nagoya/items/a13ea3823441c430edff

Qiitaに投稿するCのStyle例(暫定)
https://qiita.com/kaizen_nagoya/items/946df1528a6a1ef2bc0d

cpprefjpのdecltypeをコンパイル試験
https://qiita.com/kaizen_nagoya/items/090909af702f0d5d8a67

MISRA C++ 5-0-16
https://qiita.com/kaizen_nagoya/items/7df2d4e05db724752a74

C++ Templates Part1 BASICS Chapter 3. Class Templates 3.2 Use of Class Template Stack stack1test.cpp
https://qiita.com/kaizen_nagoya/items/cd5fc49106fad5a4e9ed

ISO/IEC TS 17961:2013 C Secure Coding Rules(1) All list(to be confirmed)
https://qiita.com/kaizen_nagoya/items/54e056195c4f11b850a1

C言語（C++)に対する誤解、曲解、無理解、爽快。
https://qiita.com/kaizen_nagoya/items/3f3992c9722c1cee2e3a

C Puzzle Bookの有り難み5つ、C言語規格及びCコンパイラの特性を認識
https://qiita.com/kaizen_nagoya/items/d89a48c1536a02ecdec9

'wchar.h' file not found で困った clang++ macOS
https://qiita.com/kaizen_nagoya/items/de15cd46d657517fac11

Open POSIX Test Suiteの使い方を調べはじめました
https://qiita.com/kaizen_nagoya/items/644d5e407f5faf96e6dc

MISRA-C 2012 Referenceに掲載している文献の入手可能性を確認
https://qiita.com/kaizen_nagoya/items/96dc8b125e462d5575bb

どうやって MISRA Example Suiteをコンパイルするか
https://qiita.com/kaizen_nagoya/items/fbdbff5ff696e2ca7f00

MISRA C まとめ #include <misra_c.h>
https://qiita.com/kaizen_nagoya/items/f1a79a7cbd281607c7c9

「C++完全理解ガイド」の同意できること上位10
https://qiita.com/kaizen_nagoya/items/aa5744e0c4a8618c7671

DoCAP（ドゥーキャップ）って何ですか？

https://qiita.com/kaizen_nagoya/items/47e0e6509ab792c43327

小川メソッド　覚え（書きかけ）

https://qiita.com/kaizen_nagoya/items/3593d72eca551742df68


 ＜この記事は個人の過去の経験に基づく個人の感想です。現在所属する組織、業務とは関係がありません。＞

# 文書履歴(document history)
ver. 0.01 初稿 　20220724