Revised wording from Ville (Part II)

Author: Dani-Hub

xml/issue2510.xml

@@ -230,26 +230,100 @@ extern const nothrow_t nothrow;
 […]
 // <i>20.3.5, pair piecewise construction</i>
 struct piecewise_construct_t { <ins>explicit piecewise_construct_t() = default;</ins> };
-constexpr piecewise_construct_t piecewise_construct{ <ins><i>unspecified</i></ins> };
+constexpr piecewise_construct_t piecewise_construct{};
+[&hellip;]
+</pre></blockquote>
+</li>
+
+<li><p>In <sref ref="[pairs.pair]"/>, change the class template <tt>pair</tt> synopsis:</p>
+
+<blockquote><pre>
+[&hellip;]
+pair(pair&amp;&amp;) = default;
+<ins><i>EXPLICIT</i></ins> constexpr pair();
+<i>EXPLICIT</i> constexpr pair(const T1&amp; x, const T2&amp; y);
 [&hellip;]
 </pre></blockquote>
 </li>
 
+<li><p>Around <sref ref="[pairs.pair]"/> p3, apply the following edits:</p>
+
+<blockquote>
+<pre>
+<ins><i>EXPLICIT</i></ins> constexpr pair();
+</pre>
+<blockquote>
+<p>
+-3- <i>Effects</i>: Value-initializes <tt>first</tt> and <tt>second</tt>.
+<p/>
+-4- <i>Remarks</i>: This constructor shall not participate in overload resolution unless 
+<tt>is_default_constructible&lt;first_type&gt;::value</tt> is <tt>true</tt> and 
+<tt>is_default_constructible&lt;second_type&gt;::value</tt> is <tt>true</tt>. 
+[<i>Note</i>: This
+behaviour can be implemented by a constructor template with default template arguments. &mdash; 
+<i>end note</i>]
+<ins>The constructor is explicit if and only if either <tt>first_type</tt> or <tt>second_type</tt> 
+is not implicitly default-constructible. 
+[<i>Note</i>: This behaviour can be implemented with a trait 
+that checks whether a <tt>const first_type&amp;</tt> or a <tt>const second_type&amp;</tt> can be 
+initialized with <tt>{}</tt>. &mdash; <i>end note</i>]</ins>
+</p>
+</blockquote>
+</blockquote>
+</li>
+
 <li><p>In <sref ref="[pair.piecewise]"/>, apply the following edits:</p>
 
 <blockquote><pre>
 struct piecewise_construct_t { <ins>explicit piecewise_construct_t() = default;</ins> };
-constexpr piecewise_construct_t piecewise_construct{ <ins><i>unspecified</i></ins> };
+constexpr piecewise_construct_t piecewise_construct{};
+</pre></blockquote>
+</li>
+
+<li><p>In <sref ref="[tuple.tuple]"/>, change the class template <tt>tuple</tt> synopsis:</p>
+
+<blockquote><pre>
+[&hellip;]
+<i>// 20.4.2.1, tuple construction</i>
+<ins><i>EXPLICIT</i></ins> constexpr tuple();
+<i>EXPLICIT</i> constexpr tuple(const Types&amp;...); <i>// only if sizeof...(Types) &gt;= 1</i>
+[&hellip;]
 </pre></blockquote>
 </li>
 
+<li><p>Around <sref ref="[tuple.cnstr]"/> p4, apply the following edits:</p>
+
+<blockquote>
+<pre>
+<ins><i>EXPLICIT</i></ins> constexpr tuple();
+</pre>
+<blockquote>
+<p>
+-4- <i>Effects</i>: Value initializes each element.
+<p/>
+-5- <i>Remarks</i>: This constructor shall not participate in overload resolution unless 
+<tt>is_default_constructible&lt;<i>T<sub>i</sub></i>&gt;::value</tt> is <tt>true</tt> for all <i>i</i>. 
+<ins>The constructor is explicit if and only if either <tt>first_type</tt> or <tt>second_type</tt> 
+is not implicitly default-constructible.</ins>
+[<i>Note</i>: This
+behaviour can be implemented by a constructor template with default template arguments. &mdash; 
+<i>end note</i>]
+<ins>The constructor is explicit if and only if any type <tt><i>T<sub>i</sub></i></tt> is not implicitly 
+default-constructible.
+[<i>Note</i>: This behaviour can be implemented with a trait that checks whether
+a <tt>const Ti&amp;</tt> can be initialized with <tt>{}</tt>. &mdash; <i>end note</i>]</ins>
+</p>
+</blockquote>
+</blockquote>
+</li>
+
 <li><p>In <sref ref="[memory.syn]"/>/1, change the header <tt>&lt;memory&gt;</tt> synopsis:</p>
 
 <blockquote><pre>
 [&hellip;]
 // <i>20.7.6, allocator argument tag</i>
 struct allocator_arg_t { <ins>explicit allocator_arg_t() = default;</ins> };
-constexpr allocator_arg_t allocator_arg{ <ins><i>unspecified</i></ins> };
+constexpr allocator_arg_t allocator_arg{};
 [&hellip;]
 </pre></blockquote>
 </li>
@@ -259,7 +333,7 @@ constexpr allocator_arg_t allocator_arg{ <ins><i>unspecified</i></ins> };
 <blockquote><pre>
 namespace std {
   struct allocator_arg_t { <ins>explicit allocator_arg_t() = default;</ins> };
-  constexpr allocator_arg_t allocator_arg{ <ins><i>unspecified</i></ins> };
+  constexpr allocator_arg_t allocator_arg{};
 }
 </pre></blockquote>
 <blockquote class="note">
@@ -285,8 +359,8 @@ We should decide whether or not to write out the <tt>std</tt> namespace in such
 paragraphs. I would suggest not to write it out.
 </p>
 </blockquote>
-
 </li>
+
 <li><p>In <sref ref="[thread.mutex]"/>/1, change the header <tt>&lt;mutex&gt;</tt> synopsis:</p>
 
 <blockquote><pre>
@@ -295,9 +369,9 @@ struct defer_lock_t { <ins>explicit defer_lock_t() = default;</ins> };
 struct try_to_lock_t { <ins>explicit try_to_lock_t() = default;</ins> };
 struct adopt_lock_t { <ins>explicit adopt_lock_t() = default;</ins> };
 
-constexpr defer_lock_t defer_lock { <ins><i>unspecified </i></ins> };
-constexpr try_to_lock_t try_to_lock { <ins><i>unspecified </i></ins> };
-constexpr adopt_lock_t adopt_lock { <ins><i>unspecified </i></ins> };
+constexpr defer_lock_t defer_lock { };
+constexpr try_to_lock_t try_to_lock { };
+constexpr adopt_lock_t adopt_lock { };
 [&hellip;]
 </pre></blockquote>
 </li>