LWG3836 std::expected<bool, E1> conversion constructor expected(const expected<U, G>&) should take precedence over expected(U&&) with operator bool

Author: burblebee

source/utilities.tex

@@ -3473,9 +3473,13 @@
 \begin{itemdescr}
 \pnum
 \constraints
-\tcode{is_constructible_v<T, U>} is \tcode{true},
-\tcode{is_same_v<remove_cvref_t<U>, in_place_t>} is \tcode{false}, and
-\tcode{is_same_v<remove_cvref_t<U>, optional>} is \tcode{false}.
+\begin{itemize}
+\item \tcode{is_constructible_v<T, U>} is \tcode{true},
+\item \tcode{is_same_v<remove_cvref_t<U>, in_place_t>} is \tcode{false},
+\item \tcode{is_same_v<remove_cvref_t<U>, optional>} is \tcode{false}, and
+\item if \tcode{T} is \cv{} \tcode{bool},
+\tcode{remove_cvref_t<U>} is not a specialization of \tcode{optional}.
+\end{itemize}
 
 \pnum
 \effects
@@ -3509,7 +3513,8 @@
 \constraints
 \begin{itemize}
 \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}.
+\item if \tcode{T} is not \cv{} \tcode{bool},
+\tcode{\exposid{converts-from-any-cvref}<T, optional<U>>} is \tcode{false}.
 \end{itemize}
 
 \pnum
@@ -3543,7 +3548,8 @@
 \constraints
 \begin{itemize}
 \item \tcode{is_constructible_v<T, U>} is \tcode{true}, and
-\item \tcode{\exposid{converts-from-any-cvref}<T, optional<U>>} is \tcode{false}.
+\item if \tcode{T} is not \cv{} \tcode{bool},
+\tcode{\exposid{converts-from-any-cvref}<T, optional<U>>} is \tcode{false}.
 \end{itemize}
 
 \pnum
@@ -7509,6 +7515,7 @@
 \item
 \tcode{is_constructible_v<E, GF>} is \tcode{true}; and
 \item
+if \tcode{T} is not \cv{} \tcode{bool},
 \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
@@ -7559,7 +7566,10 @@
 \item
 \tcode{remove_cvref_t<U>} is not a specialization of \tcode{unexpected}; and
 \item
-\tcode{is_constructible_v<T, U>} is \tcode{true}.
+\tcode{is_constructible_v<T, U>} is \tcode{true}; and
+\item
+if \tcode{T} is \cv{} \tcode{bool},
+\tcode{remove_cvref_t<U>} is not a specialization of \tcode{expected}.
 \end{itemize}
 
 \pnum