From Jason Turner

[meta.trans]

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  1. tmp/tmpzes6o_g2/{from.md → to.md} +34 -20
tmp/tmpzes6o_g2/{from.md → to.md} RENAMED
@@ -8,44 +8,59 @@ transform one type to another following some predefined rule.
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  Each of the templates in [[meta.trans]] shall be a
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  *Cpp17TransformationTrait* [[meta.rqmts]].
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  #### Const-volatile modifications <a id="meta.trans.cv">[[meta.trans.cv]]</a>
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  #### Reference modifications <a id="meta.trans.ref">[[meta.trans.ref]]</a>
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  #### Sign modifications <a id="meta.trans.sign">[[meta.trans.sign]]</a>
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  #### Array modifications <a id="meta.trans.arr">[[meta.trans.arr]]</a>
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19
  [*Example 1*:
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  ``` cpp
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  // the following assertions hold:
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- assert((is_same_v<remove_extent_t<int>, int>));
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- assert((is_same_v<remove_extent_t<int[2]>, int>));
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- assert((is_same_v<remove_extent_t<int[2][3]>, int[3]>));
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- assert((is_same_v<remove_extent_t<int[][3]>, int[3]>));
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  ```
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29
  — *end example*]
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  [*Example 2*:
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  ``` cpp
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  // the following assertions hold:
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- assert((is_same_v<remove_all_extents_t<int>, int>));
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- assert((is_same_v<remove_all_extents_t<int[2]>, int>));
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- assert((is_same_v<remove_all_extents_t<int[2][3]>, int>));
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- assert((is_same_v<remove_all_extents_t<int[][3]>, int>));
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  ```
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  — *end example*]
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43
  #### Pointer modifications <a id="meta.trans.ptr">[[meta.trans.ptr]]</a>
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  #### Other transformations <a id="meta.trans.other">[[meta.trans.other]]</a>
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  [*Note 1*: The compilation of the expression can result in side effects
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  such as the instantiation of class template specializations and function
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  template specializations, the generation of implicitly-defined
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  functions, and so on. Such side effects are not in the “immediate
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  context” and can result in the program being ill-formed. — *end note*]
@@ -86,13 +101,13 @@ Given types `A` and `B`, let `X` be `remove_reference_t<A>`, let `Y` be
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  - Otherwise, `COMMON-REF(A, B)` is ill-formed.
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88
  If any of the types computed above is ill-formed, then
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  `COMMON-REF(A, B)` is ill-formed.
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- Note A: For the `common_type` trait applied to a template parameter pack
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- `T` of types, the member `type` shall be either defined or not present
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- as follows:
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  - If `sizeof...(T)` is zero, there shall be no member `type`.
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  - If `sizeof...(T)` is one, let `T0` denote the sole type constituting
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  the pack `T`. The member *typedef-name* `type` shall denote the same
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  type, if any, as `common_type_t<T0, T0>`; otherwise there shall be no
@@ -123,15 +138,14 @@ as follows:
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  constituting `T`. Let `C` denote the same type, if any, as
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  `common_type_t<T1, T2>`. If there is such a type `C`, the member
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  *typedef-name* `type` shall denote the same type, if any, as
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  `common_type_t<C, R...>`. Otherwise, there shall be no member `type`.
127
 
128
- Note B: Notwithstanding the provisions of [[meta.type.synop]], and
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- pursuant to [[namespace.std]], a program may specialize
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- `common_type<T1, T2>` for types `T1` and `T2` such that
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- `is_same_v<T1, decay_t<T1>>` and `is_same_v<T2, decay_t<T2>>` are each
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- `true`.
133
 
134
  [*Note 3*: Such specializations are needed when only explicit
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  conversions are desired between the template arguments. — *end note*]
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  Such a specialization need not have a member named `type`, but if it
@@ -139,12 +153,12 @@ does, the *qualified-id* `common_type<T1, T2>::type` shall denote a
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  cv-unqualified non-reference type to which each of the types `T1` and
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  `T2` is explicitly convertible. Moreover, `common_type_t<T1, T2>` shall
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  denote the same type, if any, as does `common_type_t<T2, T1>`. No
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  diagnostic is required for a violation of this Note’s rules.
143
 
144
- Note C: For the `common_reference` trait applied to a parameter pack `T`
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- of types, the member `type` shall be either defined or not present as
146
  follows:
147
 
148
  - If `sizeof...(T)` is zero, there shall be no member `type`.
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  - Otherwise, if `sizeof...(T)` is one, let `T0` denote the sole type in
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  the pack `T`. The member typedef `type` shall denote the same type as
@@ -170,12 +184,12 @@ follows:
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  `common_reference_t<T1, T2>`. Then:
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  - If there is such a type `C`, the member typedef `type` shall denote
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  the same type, if any, as `common_reference_t<C, Rest...>`.
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  - Otherwise, there shall be no member `type`.
174
 
175
- Note D: Notwithstanding the provisions of [[meta.type.synop]], and
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- pursuant to [[namespace.std]], a program may partially specialize
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  `basic_common_reference<T, U, TQual, UQual>` for types `T` and `U` such
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  that `is_same_v<T, decay_t<T>>` and `is_same_v<U, decay_t<U>>` are each
179
  `true`.
180
 
181
  [*Note 4*: Such specializations can be used to influence the result of
 
8
  Each of the templates in [[meta.trans]] shall be a
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  *Cpp17TransformationTrait* [[meta.rqmts]].
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11
  #### Const-volatile modifications <a id="meta.trans.cv">[[meta.trans.cv]]</a>
12
 
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+ The templates specified in [[meta.trans.cv]] add or remove
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+ cv-qualifications [[basic.type.qualifier]].
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+
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  #### Reference modifications <a id="meta.trans.ref">[[meta.trans.ref]]</a>
17
 
18
+ The templates specified in [[meta.trans.ref]] add or remove references.
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+
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  #### Sign modifications <a id="meta.trans.sign">[[meta.trans.sign]]</a>
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+ The templates specified in [[meta.trans.sign]] convert an integer type
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+ to its corresponding signed or unsigned type.
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+
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  #### Array modifications <a id="meta.trans.arr">[[meta.trans.arr]]</a>
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+ The templates specified in [[meta.trans.arr]] modify array types.
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+
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  [*Example 1*:
30
 
31
  ``` cpp
32
  // the following assertions hold:
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+ static_assert(is_same_v<remove_extent_t<int>, int>);
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+ static_assert(is_same_v<remove_extent_t<int[2]>, int>);
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+ static_assert(is_same_v<remove_extent_t<int[2][3]>, int[3]>);
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+ static_assert(is_same_v<remove_extent_t<int[][3]>, int[3]>);
37
  ```
38
 
39
  — *end example*]
40
 
41
  [*Example 2*:
42
 
43
  ``` cpp
44
  // the following assertions hold:
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+ static_assert(is_same_v<remove_all_extents_t<int>, int>);
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+ static_assert(is_same_v<remove_all_extents_t<int[2]>, int>);
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+ static_assert(is_same_v<remove_all_extents_t<int[2][3]>, int>);
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+ static_assert(is_same_v<remove_all_extents_t<int[][3]>, int>);
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  ```
50
 
51
  — *end example*]
52
 
53
  #### Pointer modifications <a id="meta.trans.ptr">[[meta.trans.ptr]]</a>
54
 
55
+ The templates specified in [[meta.trans.ptr]] add or remove pointers.
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+
57
  #### Other transformations <a id="meta.trans.other">[[meta.trans.other]]</a>
58
 
59
+ The templates specified in [[meta.trans.other]] perform other
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+ modifications of a type.
61
+
62
  [*Note 1*: The compilation of the expression can result in side effects
63
  such as the instantiation of class template specializations and function
64
  template specializations, the generation of implicitly-defined
65
  functions, and so on. Such side effects are not in the “immediate
66
  context” and can result in the program being ill-formed. — *end note*]
 
101
  - Otherwise, `COMMON-REF(A, B)` is ill-formed.
102
 
103
  If any of the types computed above is ill-formed, then
104
  `COMMON-REF(A, B)` is ill-formed.
105
 
106
+ For the `common_type` trait applied to a template parameter pack `T` of
107
+ types, the member `type` shall be either defined or not present as
108
+ follows:
109
 
110
  - If `sizeof...(T)` is zero, there shall be no member `type`.
111
  - If `sizeof...(T)` is one, let `T0` denote the sole type constituting
112
  the pack `T`. The member *typedef-name* `type` shall denote the same
113
  type, if any, as `common_type_t<T0, T0>`; otherwise there shall be no
 
138
  constituting `T`. Let `C` denote the same type, if any, as
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  `common_type_t<T1, T2>`. If there is such a type `C`, the member
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  *typedef-name* `type` shall denote the same type, if any, as
141
  `common_type_t<C, R...>`. Otherwise, there shall be no member `type`.
142
 
143
+ Notwithstanding the provisions of [[meta.rqmts]], and pursuant to
144
+ [[namespace.std]], a program may specialize `common_type<T1, T2>` for
145
+ types `T1` and `T2` such that `is_same_v<T1, decay_t<T1>>` and
146
+ `is_same_v<T2, decay_t<T2>>` are each `true`.
 
147
 
148
  [*Note 3*: Such specializations are needed when only explicit
149
  conversions are desired between the template arguments. — *end note*]
150
 
151
  Such a specialization need not have a member named `type`, but if it
 
153
  cv-unqualified non-reference type to which each of the types `T1` and
154
  `T2` is explicitly convertible. Moreover, `common_type_t<T1, T2>` shall
155
  denote the same type, if any, as does `common_type_t<T2, T1>`. No
156
  diagnostic is required for a violation of this Note’s rules.
157
 
158
+ For the `common_reference` trait applied to a parameter pack `T` of
159
+ types, the member `type` shall be either defined or not present as
160
  follows:
161
 
162
  - If `sizeof...(T)` is zero, there shall be no member `type`.
163
  - Otherwise, if `sizeof...(T)` is one, let `T0` denote the sole type in
164
  the pack `T`. The member typedef `type` shall denote the same type as
 
184
  `common_reference_t<T1, T2>`. Then:
185
  - If there is such a type `C`, the member typedef `type` shall denote
186
  the same type, if any, as `common_reference_t<C, Rest...>`.
187
  - Otherwise, there shall be no member `type`.
188
 
189
+ Notwithstanding the provisions of [[meta.rqmts]], and pursuant to
190
+ [[namespace.std]], a program may partially specialize
191
  `basic_common_reference<T, U, TQual, UQual>` for types `T` and `U` such
192
  that `is_same_v<T, decay_t<T>>` and `is_same_v<U, decay_t<U>>` are each
193
  `true`.
194
 
195
  [*Note 4*: Such specializations can be used to influence the result of