CWG3063 Lifetime extension of temporaries past function return

eisenwave · tkoeppe · commit 98bf7ee0a3b2 · 2025-12-13T17:13:25.000Z
Fixes NB CA 040 (C++26 CD).
diff --git a/source/basic.tex b/source/basic.tex
@@ -3667,6 +3667,24 @@
 the address of an unspecified byte of storage
 occupied by the complete object of that subobject.
 
+\pnum
+The \defnx{constituent values}{constituent value} of an object $o$ are
+\begin{itemize}
+\item
+if $o$ has scalar type, the value of $o$;
+\item
+otherwise, the constituent values of any direct subobjects of $o$
+other than inactive union members.
+\end{itemize}
+The \defnx{constituent references}{constituent reference} of an object $o$ are
+\begin{itemize}
+\item
+any direct members of $o$ that have reference type, and
+\item
+the constituent references of any direct subobjects of $o$
+other than inactive union members.
+\end{itemize}
+
 \pnum
 Some operations are described as
 \defnx{implicitly creating objects}{object!implicit creation}
diff --git a/source/expressions.tex b/source/expressions.tex
@@ -8291,31 +8291,13 @@
     conditional-expression
 \end{bnf}
 
-\pnum
-The \defnx{constituent values}{constituent value} of an object $o$ are
-\begin{itemize}
-\item
-if $o$ has scalar type, the value of $o$;
-\item
-otherwise, the constituent values of any direct subobjects of $o$
-other than inactive union members.
-\end{itemize}
-The \defnx{constituent references}{constituent reference} of an object $o$ are
-\begin{itemize}
-\item
-any direct members of $o$ that have reference type, and
-\item
-the constituent references of any direct subobjects of $o$
-other than inactive union members.
-\end{itemize}
-
 \pnum
 The constituent values and constituent references of
 a variable \tcode{x} are defined as follows:
 \begin{itemize}
 \item
 If \tcode{x} declares an object,
-the constituent values and references of that object are
+the constituent values and references of that object\iref{intro.object} are
 constituent values and references of \tcode{x}.
 \item
 If \tcode{x} declares a reference,
diff --git a/source/statements.tex b/source/statements.tex
@@ -1142,10 +1142,14 @@
 \end{note}
 
 \pnum
-In a function whose return type is a reference,
+In a function
 other than an invented function for \tcode{std::is_convertible}\iref{meta.rel},
-a \tcode{return} statement that binds the returned reference to
-a temporary expression\iref{class.temporary} is ill-formed.
+a \tcode{return} statement that binds
+\begin{itemize}
+\item a returned reference or
+\item a constituent reference\iref{intro.object} of a returned object
+\end{itemize}
+to a temporary expression\iref{class.temporary} is ill-formed.
 \begin{example}
 \begin{codeblock}
 auto&& f1() {
