[ub.cpp.concat] Remove universal-character-name formation from ##; no…

…w well-defined
cplusplus · jensmaurer · Apr 5, 2025 · Apr 5, 2025 · Apr 11, 2025 · Apr 11, 2025
commit d06ddfe7df3a79ce40da337734a35af9adc22bb7
diff --git a/source/ub.tex b/source/ub.tex
@@ -1660,21 +1660,6 @@
 
 \rSec2[ub.cpp.concat]{The \#\# operator}
 
-\pnum
-\ubxref{cpp.concat.universal.char} \\
-If a character sequence that matches the syntax of a \grammarterm{universal-character-name}
-is produced by token concatenation \iref{cpp.concat}, the behavior is undefined.
-
-\pnum
-\begin{example}
-\begin{codeblock}
-#define GUARD_NAME ï ## _GUARD // undefined behavior, character sequence produced contains
-                               // a \grammarterm{universal-character-name}
-#define COLUMN ï ##_column     // undefined behavior, character sequence produced contains
-                               // a \grammarterm{universal-character-name}
-\end{codeblock}
-\end{example}
-
 \pnum
 \ubxref{cpp.concat.invalid.preprocessing.token} \\
 If an invalid preprocessing token results from using the concat operator the behavior is undefined.