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[tuple.tuple]

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tmp/tmpvda0ou8p/{from.md → to.md} RENAMED
@@ -1,7 +1,9 @@
1
  ### Class template `tuple` <a id="tuple.tuple">[[tuple.tuple]]</a>
2
 
 
 
3
  ``` cpp
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  namespace std {
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  template<class... Types>
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  class tuple {
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  public:
@@ -123,10 +125,13 @@ namespace std {
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  template<class Alloc, class... UTypes>
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  tuple(allocator_arg_t, Alloc, tuple<UTypes...>) -> tuple<UTypes...>;
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  }
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  ```
127
 
 
 
 
128
  #### Construction <a id="tuple.cnstr">[[tuple.cnstr]]</a>
129
 
130
  In the descriptions that follow, let i be in the range \[`0`,
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  `sizeof...(Types)`) in order, `Tᵢ` be the iᵗʰ type in `Types`, and `Uᵢ`
132
  be the iᵗʰ type in a template parameter pack named `UTypes`, where
@@ -237,11 +242,11 @@ template<class... UTypes> constexpr explicit(see below) tuple(tuple<UTypes...>&
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  template<class... UTypes> constexpr explicit(see below) tuple(const tuple<UTypes...>& u);
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  template<class... UTypes> constexpr explicit(see below) tuple(tuple<UTypes...>&& u);
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  template<class... UTypes> constexpr explicit(see below) tuple(const tuple<UTypes...>&& u);
240
  ```
241
 
242
- Let `I` be the pack `0, 1, ..., (sizeof...(Types) - 1)`. Let
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  *`FWD`*`(u)` be `static_cast<decltype(u)>(u)`.
244
 
245
  *Constraints:*
246
 
247
  - `sizeof...(Types)` equals `sizeof...(UTypes)`, and
@@ -308,21 +313,21 @@ is `true`.
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  ``` cpp
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  template<tuple-like UTuple>
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  constexpr explicit(see below) tuple(UTuple&& u);
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  ```
312
 
313
- Let `I` be the pack `0, 1, …, (sizeof...(Types) - 1)`.
314
 
315
  *Constraints:*
316
 
317
  - `different-from<UTuple, tuple>` [[range.utility.helpers]] is `true`,
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  - `remove_cvref_t<UTuple>` is not a specialization of
319
  `ranges::subrange`,
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  - `sizeof...(Types)` equals `tuple_size_v<remove_cvref_t<UTuple>>`,
321
  - `(is_constructible_v<Types, decltype(get<I>(std::forward<UTuple>(u)))> && ...)`
322
  is `true`, and
323
- - either `sizeof...(Types)` is not `1`, or (when `Types...` expands to
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  `T`) `is_convertible_v<UTuple, T>` and `is_constructible_v<T, UTuple>`
325
  are both `false`.
326
 
327
  *Effects:* For all i, initializes the iᵗʰ element of `*this` with
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  `get<`i`>(std::forward<UTuple>(u))`.
@@ -331,10 +336,19 @@ Let `I` be the pack `0, 1, …, (sizeof...(Types) - 1)`.
331
 
332
  ``` cpp
333
  !(is_convertible_v<decltype(get<I>(std::forward<UTuple>(u))), Types> && ...)
334
  ```
335
 
 
 
 
 
 
 
 
 
 
336
  ``` cpp
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  template<class Alloc>
338
  constexpr explicit(see below)
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  tuple(allocator_arg_t, const Alloc& a);
340
  template<class Alloc>
@@ -573,11 +587,11 @@ template<tuple-like UTuple>
573
  *Constraints:*
574
 
575
  - `different-from<UTuple, tuple>` [[range.utility.helpers]] is `true`,
576
  - `remove_cvref_t<UTuple>` is not a specialization of
577
  `ranges::subrange`,
578
- - `sizeof...(Types)` equals `tuple_size_v<remove_cvref_t<UTuple>>`, and,
579
  - `is_assignable_v<``Tᵢ``&, decltype(get<`i`>(std::forward<UTuple>(u)))>`
580
  is `true` for all i.
581
 
582
  *Effects:* For all i, assigns `get<`i`>(std::forward<UTuple>(u))` to
583
  `get<`i`>(*this)`.
@@ -592,11 +606,11 @@ template<tuple-like UTuple>
592
  *Constraints:*
593
 
594
  - `different-from<UTuple, tuple>` [[range.utility.helpers]] is `true`,
595
  - `remove_cvref_t<UTuple>` is not a specialization of
596
  `ranges::subrange`,
597
- - `sizeof...(Types)` equals `tuple_size_v<remove_cvref_t<UTuple>>`, and,
598
  - `is_assignable_v<const ``Tᵢ``&, decltype(get<`i`>(std::forward<UTuple>(u)))>`
599
  is `true` for all i.
600
 
601
  *Effects:* For all i, assigns `get<`i`>(std::forward<UTuple>(u))` to
602
  `get<`i`>(*this)`.
@@ -619,11 +633,11 @@ Let i be in the range \[`0`, `sizeof...(Types)`) in order.
619
  `true`.
620
 
621
  *Preconditions:* For all i, `get<`i`>(*this)` is swappable
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  with [[swappable.requirements]] `get<`i`>(rhs)`.
623
 
624
- *Effects:* For each i, calls `swap` for `get<`i`>(*this)` with
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  `get<`i`>(rhs)`.
626
 
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  *Throws:* Nothing unless one of the element-wise `swap` calls throws an
628
  exception.
629
 
 
1
  ### Class template `tuple` <a id="tuple.tuple">[[tuple.tuple]]</a>
2
 
3
+ #### General <a id="tuple.tuple.general">[[tuple.tuple.general]]</a>
4
+
5
  ``` cpp
6
  namespace std {
7
  template<class... Types>
8
  class tuple {
9
  public:
 
125
  template<class Alloc, class... UTypes>
126
  tuple(allocator_arg_t, Alloc, tuple<UTypes...>) -> tuple<UTypes...>;
127
  }
128
  ```
129
 
130
+ If a program declares an explicit or partial specialization of `tuple`,
131
+ the program is ill-formed, no diagnostic required.
132
+
133
  #### Construction <a id="tuple.cnstr">[[tuple.cnstr]]</a>
134
 
135
  In the descriptions that follow, let i be in the range \[`0`,
136
  `sizeof...(Types)`) in order, `Tᵢ` be the iᵗʰ type in `Types`, and `Uᵢ`
137
  be the iᵗʰ type in a template parameter pack named `UTypes`, where
 
242
  template<class... UTypes> constexpr explicit(see below) tuple(const tuple<UTypes...>& u);
243
  template<class... UTypes> constexpr explicit(see below) tuple(tuple<UTypes...>&& u);
244
  template<class... UTypes> constexpr explicit(see below) tuple(const tuple<UTypes...>&& u);
245
  ```
246
 
247
+ Let `I` be the pack `0, 1, `…`, (sizeof...(Types) - 1)`. Let
248
  *`FWD`*`(u)` be `static_cast<decltype(u)>(u)`.
249
 
250
  *Constraints:*
251
 
252
  - `sizeof...(Types)` equals `sizeof...(UTypes)`, and
 
313
  ``` cpp
314
  template<tuple-like UTuple>
315
  constexpr explicit(see below) tuple(UTuple&& u);
316
  ```
317
 
318
+ Let `I` be the pack `0, 1, `…`, (sizeof...(Types) - 1)`.
319
 
320
  *Constraints:*
321
 
322
  - `different-from<UTuple, tuple>` [[range.utility.helpers]] is `true`,
323
  - `remove_cvref_t<UTuple>` is not a specialization of
324
  `ranges::subrange`,
325
  - `sizeof...(Types)` equals `tuple_size_v<remove_cvref_t<UTuple>>`,
326
  - `(is_constructible_v<Types, decltype(get<I>(std::forward<UTuple>(u)))> && ...)`
327
  is `true`, and
328
+ - either `sizeof...(Types)` is not 1, or (when `Types...` expands to
329
  `T`) `is_convertible_v<UTuple, T>` and `is_constructible_v<T, UTuple>`
330
  are both `false`.
331
 
332
  *Effects:* For all i, initializes the iᵗʰ element of `*this` with
333
  `get<`i`>(std::forward<UTuple>(u))`.
 
336
 
337
  ``` cpp
338
  !(is_convertible_v<decltype(get<I>(std::forward<UTuple>(u))), Types> && ...)
339
  ```
340
 
341
+ The constructor is defined as deleted if
342
+
343
+ ``` cpp
344
+ (reference_constructs_from_temporary_v<Types, decltype(get<I>(std::forward<UTuple>(u)))>
345
+ || ...)
346
+ ```
347
+
348
+ is `true`.
349
+
350
  ``` cpp
351
  template<class Alloc>
352
  constexpr explicit(see below)
353
  tuple(allocator_arg_t, const Alloc& a);
354
  template<class Alloc>
 
587
  *Constraints:*
588
 
589
  - `different-from<UTuple, tuple>` [[range.utility.helpers]] is `true`,
590
  - `remove_cvref_t<UTuple>` is not a specialization of
591
  `ranges::subrange`,
592
+ - `sizeof...(Types)` equals `tuple_size_v<remove_cvref_t<UTuple>>`, and
593
  - `is_assignable_v<``Tᵢ``&, decltype(get<`i`>(std::forward<UTuple>(u)))>`
594
  is `true` for all i.
595
 
596
  *Effects:* For all i, assigns `get<`i`>(std::forward<UTuple>(u))` to
597
  `get<`i`>(*this)`.
 
606
  *Constraints:*
607
 
608
  - `different-from<UTuple, tuple>` [[range.utility.helpers]] is `true`,
609
  - `remove_cvref_t<UTuple>` is not a specialization of
610
  `ranges::subrange`,
611
+ - `sizeof...(Types)` equals `tuple_size_v<remove_cvref_t<UTuple>>`, and
612
  - `is_assignable_v<const ``Tᵢ``&, decltype(get<`i`>(std::forward<UTuple>(u)))>`
613
  is `true` for all i.
614
 
615
  *Effects:* For all i, assigns `get<`i`>(std::forward<UTuple>(u))` to
616
  `get<`i`>(*this)`.
 
633
  `true`.
634
 
635
  *Preconditions:* For all i, `get<`i`>(*this)` is swappable
636
  with [[swappable.requirements]] `get<`i`>(rhs)`.
637
 
638
+ *Effects:* For each i, calls `swap` for `get<`i`>(*this)` and
639
  `get<`i`>(rhs)`.
640
 
641
  *Throws:* Nothing unless one of the element-wise `swap` calls throws an
642
  exception.
643