LWG4316 {can_}substitute specification is ill-formed

Author: burblebee

source/meta.tex

@@ -6217,6 +6217,19 @@
 
 \rSec2[meta.reflection.substitute]{Reflection substitution}
 
+\pnum
+Let \tcode{\placeholder{TARG-SPLICE}(x)} be:
+\begin{itemize}
+\item
+\tcode{template [: x :]} if \tcode{is_template(x)} is \tcode{true}, otherwise
+
+\item
+\tcode{typename [: x :]} if \tcode{is_type(x)} is \tcode{true}, otherwise
+
+\item
+\tcode{([: x :])}.
+\end{itemize}
+
 \begin{itemdecl}
 template<class R>
 concept @\deflibconcept{reflection_range}@ =
@@ -6237,7 +6250,7 @@
 
 \pnum
 \returns
-\tcode{true} if \tcode{Z<[:Args:]...>} is a valid \grammarterm{template-id}\iref{temp.names}
+\tcode{true} if \tcode{Z<\placeholder{TARG-SPLICE}(Args)...>} is a valid \grammarterm{template-id}\iref{temp.names}
 that does not name a function
 whose type contains an undeduced placeholder type.
 Otherwise, \tcode{false}.
@@ -6251,7 +6264,7 @@
 
 \pnum
 \begin{note}
-If forming \tcode{Z<[:Args:]...>} leads to a failure
+If forming \tcode{Z<\placeholder{TARG-SPLICE}(Args)...>} leads to a failure
 outside of the immediate context,
 the program is ill-formed.
 \end{note}
@@ -6272,7 +6285,7 @@
 
 \pnum
 \returns
-\tcode{\reflexpr{Z<[:Args:]...>}}.
+\tcode{\reflexpr{Z<\placeholder{TARG-SPLICE}(Args)...>}}.
 
 \pnum
 \throws
@@ -6281,7 +6294,7 @@
 
 \pnum
 \begin{note}
-If forming \tcode{Z<[:Args:]...>} leads to a failure outside of the immediate context,
+If forming \tcode{Z<\placeholder{TARG-SPLICE}(Args)...>} leads to a failure outside of the immediate context,
 the program is ill-formed.
 \end{note}