LWG3940 std::expected<void, E>::value() also needs E to be copy constructible

Author: burblebee

source/utilities.tex

@@ -9188,6 +9188,10 @@
 \end{itemdecl}
 
 \begin{itemdescr}
+\pnum
+\mandates
+\tcode{is_copy_constructible_v<E>} is \tcode{true}.
+
 \pnum
 \throws
 \tcode{bad_expected_access(error())} if \tcode{has_value()} is \tcode{false}.
@@ -9199,6 +9203,11 @@
 \end{itemdecl}
 
 \begin{itemdescr}
+\pnum
+\mandates
+\tcode{is_copy_constructible_v<E>} is \tcode{true} and
+\tcode{is_move_constructible_v<E>} is \tcode{true}.
+
 \pnum
 \throws
 \tcode{bad_expected_access(std::move(error()))}