[optional.ctor], [expected.object.ctor] Add converts-from-any-cvref

Author: jwakely

source/utilities.tex

@@ -3319,6 +3319,18 @@
 
 \rSec3[optional.ctor]{Constructors}
 
+\pnum
+The exposition-only variable template \exposid{converts-from-any-cvref}
+is used by some constructors for \tcode{optional}.
+\begin{codeblock}
+template<class T, class W>
+constexpr bool @\exposid{converts-from-any-cvref}@ =  // \expos
+  disjunction_v<is_constructible<T, W&>, is_convertible<W&, T>,
+                is_constructible<T, W>, is_convertible<W, T>,
+                is_constructible<T, const W&>, is_convertible<const W&, T>,
+                is_constructible<T, const W>, is_convertible<const W, T>>;
+\end{codeblock}
+
 \indexlibraryctor{optional}%
 \begin{itemdecl}
 constexpr optional() noexcept;
@@ -3493,15 +3505,8 @@
 \pnum
 \constraints
 \begin{itemize}
-\item \tcode{is_constructible_v<T, const U\&>} is \tcode{true},
-\item \tcode{is_constructible_v<T, optional<U>\&>} is \tcode{false},
-\item \tcode{is_constructible_v<T, optional<U>\&\&>} is \tcode{false},
-\item \tcode{is_constructible_v<T, const optional<U>\&>} is \tcode{false},
-\item \tcode{is_constructible_v<T, const optional<U>\&\&>} is \tcode{false},
-\item \tcode{is_convertible_v<optional<U>\&, T>} is \tcode{false},
-\item \tcode{is_convertible_v<optional<U>\&\&, T>} is \tcode{false},
-\item \tcode{is_convertible_v<const optional<U>\&, T>} is \tcode{false}, and
-\item \tcode{is_convertible_v<const optional<U>\&\&, T>} is \tcode{false}.
+\item \tcode{is_constructible_v<T, const U\&>} is \tcode{true}, and
+\item \tcode{\exposid{converts-from-any-cvref}<T, optional<U>>} is \tcode{false}.
 \end{itemize}
 
 \pnum
@@ -3534,15 +3539,8 @@
 \pnum
 \constraints
 \begin{itemize}
-\item \tcode{is_constructible_v<T, U>} is \tcode{true},
-\item \tcode{is_constructible_v<T, optional<U>\&>} is \tcode{false},
-\item \tcode{is_constructible_v<T, optional<U>\&\&>} is \tcode{false},
-\item \tcode{is_constructible_v<T, const optional<U>\&>} is \tcode{false},
-\item \tcode{is_constructible_v<T, const optional<U>\&\&>} is \tcode{false},
-\item \tcode{is_convertible_v<optional<U>\&, T>} is \tcode{false},
-\item \tcode{is_convertible_v<optional<U>\&\&, T>} is \tcode{false},
-\item \tcode{is_convertible_v<const optional<U>\&, T>} is \tcode{false}, and
-\item \tcode{is_convertible_v<const optional<U>\&\&, T>} is \tcode{false}.
+\item \tcode{is_constructible_v<T, U>} is \tcode{true}, and
+\item \tcode{\exposid{converts-from-any-cvref}<T, optional<U>>} is \tcode{false}.
 \end{itemize}
 
 \pnum
@@ -3751,14 +3749,7 @@
 \begin{itemize}
 \item \tcode{is_constructible_v<T, const U\&>} is \tcode{true},
 \item \tcode{is_assignable_v<T\&, const U\&>} is \tcode{true},
-\item \tcode{is_constructible_v<T, optional<U>\&>} is \tcode{false},
-\item \tcode{is_constructible_v<T, optional<U>\&\&>} is \tcode{false},
-\item \tcode{is_constructible_v<T, const optional<U>\&>} is \tcode{false},
-\item \tcode{is_constructible_v<T, const optional<U>\&\&>} is \tcode{false},
-\item \tcode{is_convertible_v<optional<U>\&, T>} is \tcode{false},
-\item \tcode{is_convertible_v<optional<U>\&\&, T>} is \tcode{false},
-\item \tcode{is_convertible_v<const optional<U>\&, T>} is \tcode{false},
-\item \tcode{is_convertible_v<const optional<U>\&\&, T>} is \tcode{false},
+\item \tcode{\exposid{converts-from-any-cvref}<T, optional<U>>} is \tcode{false},
 \item \tcode{is_assignable_v<T\&, optional<U>\&>} is \tcode{false},
 \item \tcode{is_assignable_v<T\&, optional<U>\&\&>} is \tcode{false},
 \item \tcode{is_assignable_v<T\&, const optional<U>\&>} is \tcode{false}, and
@@ -3813,14 +3804,7 @@
 \begin{itemize}
 \item \tcode{is_constructible_v<T, U>} is \tcode{true},
 \item \tcode{is_assignable_v<T\&, U>} is \tcode{true},
-\item \tcode{is_constructible_v<T, optional<U>\&>} is \tcode{false},
-\item \tcode{is_constructible_v<T, optional<U>\&\&>} is \tcode{false},
-\item \tcode{is_constructible_v<T, const optional<U>\&>} is \tcode{false},
-\item \tcode{is_constructible_v<T, const optional<U>\&\&>} is \tcode{false},
-\item \tcode{is_convertible_v<optional<U>\&, T>} is \tcode{false},
-\item \tcode{is_convertible_v<optional<U>\&\&, T>} is \tcode{false},
-\item \tcode{is_convertible_v<const optional<U>\&, T>} is \tcode{false},
-\item \tcode{is_convertible_v<const optional<U>\&\&, T>} is \tcode{false},
+\item \tcode{\exposid{converts-from-any-cvref}<T, optional<U>>} is \tcode{false},
 \item \tcode{is_assignable_v<T\&, optional<U>\&>} is \tcode{false},
 \item \tcode{is_assignable_v<T\&, optional<U>\&\&>} is \tcode{false},
 \item \tcode{is_assignable_v<T\&, const optional<U>\&>} is \tcode{false}, and
@@ -7377,6 +7361,11 @@
 
 \rSec3[expected.object.cons]{Constructors}
 
+\pnum
+The exposition-only variable template \exposid{converts-from-any-cvref}
+defined in \ref{optional.ctor}
+is used by some constructors for \tcode{expected}.
+
 \indexlibraryctor{expected}%
 \begin{itemdecl}
 constexpr expected();
@@ -7515,21 +7504,7 @@
 \item
 \tcode{is_constructible_v<E, GF>} is \tcode{true}; and
 \item
-\tcode{is_constructible_v<T, expected<U, G>\&>} is \tcode{false}; and
-\item
-\tcode{is_constructible_v<T, expected<U, G>>} is \tcode{false}; and
-\item
-\tcode{is_constructible_v<T, const expected<U, G>\&>} is \tcode{false}; and
-\item
-\tcode{is_constructible_v<T, const expected<U, G>>} is \tcode{false}; and
-\item
-\tcode{is_convertible_v<expected<U, G>\&, T>} is \tcode{false}; and
-\item
-\tcode{is_convertible_v<expected<U, G>\&\&, T>} is \tcode{false}; and
-\item
-\tcode{is_convertible_v<const expected<U, G>\&, T>} is \tcode{false}; and
-\item
-\tcode{is_convertible_v<const expected<U, G>\&\&, T>} is \tcode{false}; and
+\tcode{\exposid{converts-from-any-cvref}<T, expected<U, G>>} is \tcode{false}; and
 \item
 \tcode{is_constructible_v<unexpected<E>, expected<U, G>\&>} is \tcode{false}; and
 \item