[2026-03 CWG Motion 8] P3598R0 CWG 3158 - const-ification of Splice Expressions

source/expressions.tex

@@ -3560,7 +3560,7 @@
 \end{example}
 
 \pnum
-For a \grammarterm{splice-expression} of the form \grammarterm{splice-specifier},
+For a \grammarterm{splice-expression} $E$ of the form \grammarterm{splice-specifier},
 let $S$ be the construct designated by \grammarterm{splice-specifier}.
 \begin{itemize}
 \item
@@ -3610,10 +3610,24 @@
 Otherwise, if $S$ is a variable or a structured binding,
 $S$ shall either have static or thread storage duration or
 shall inhabit a scope enclosing the expression.
-The expression is an lvalue referring to the object or function $X$
-associated with or referenced by $S$,
-has the same type as that of $S$, and
+$E$ is an lvalue referring to the object or function $X$
+associated with or referenced by $S$, and
 is a bit-field if and only if $X$ is a bit-field.
+If $E$ appears in the predicate of a contract assertion C\iref{basic.contract}
+and $S$ is
+\begin{itemize}
+\item
+a variable declared outside of $C$
+of object type \tcode{T},
+\item
+a variable declared outside of $C$
+of type ``reference to \tcode{T}'', or
+\item
+a structured binding of type \tcode{T}
+whose corresponding variable is declared outside of $C$,
+\end{itemize}
+then the type of $E$ is \tcode{const T},
+otherwise $E$ has the same type as that of $S$.
 \begin{note}
 The type of a \grammarterm{splice-expression}
 designating a variable or structured binding of reference type