LWG3436 std::construct_at should support arrays

Author: burblebee

source/algorithms.tex

@@ -11741,14 +11741,22 @@
 \begin{itemdescr}
 \pnum
 \constraints
-The expression \tcode{::new (declval<void*>()) T(declval<Args>()...)}
+\tcode{is_unbounded_array_v<T>} is \tcode{false}.
+The expression \tcode{::new (declval<void*>()) T(\linebreak{}declval<Args>()...)}
 is well-formed when treated as an unevaluated operand\iref{term.unevaluated.operand}.
 
+\pnum
+\mandates
+If \tcode{is_array_v<T>} is \tcode{true}, \tcode{sizeof...(Args)} is zero.
+
 \pnum
 \effects
 Equivalent to:
 \begin{codeblock}
-return ::new (@\placeholdernc{voidify}@(*location)) T(std::forward<Args>(args)...);
+if constexpr (is_array_v<T>)
+  return ::new (@\placeholdernc{voidify}@(*location)) T[1]();
+else
+  return ::new (@\placeholdernc{voidify}@(*location)) T(std::forward<Args>(args)...);
 \end{codeblock}
 \end{itemdescr}