CWG2818 Use of predefined reserved identifiers

Author: burblebee

source/lex.tex

@@ -899,7 +899,9 @@
 \tcode{\unun}
 \indextext{character!underscore}%
 or begins with an underscore followed by
-an uppercase letter
+an uppercase letter,
+other than those specified in this document
+(for example, \xname{cplusplus}\iref{cpp.predefined}),
 \indextext{uppercase}%
 is reserved to the implementation for any use.
 \item