CWG2621 Kind of lookup for using enum declarations

Fixes NB CA 054 (C++23 CD).

Author: burblebee

source/declarations.tex

@@ -1356,11 +1356,6 @@
     class-key \opt{attribute-specifier-seq} \opt{nested-name-specifier} identifier\br
     class-key simple-template-id\br
     class-key nested-name-specifier \opt{\keyword{template}} simple-template-id\br
-    elaborated-enum-specifier
-\end{bnf}
-
-\begin{bnf}
-\nontermdef{elaborated-enum-specifier}\br
     \keyword{enum} \opt{nested-name-specifier} identifier
 \end{bnf}
 
@@ -7161,13 +7156,23 @@
 
 \begin{bnf}
 \nontermdef{using-enum-declaration}\br
-    \terminal{using} elaborated-enum-specifier \terminal{;}
+    \keyword{using} \keyword{enum} using-enum-declarator \terminal{;}
+\end{bnf}
+
+\begin{bnf}
+\nontermdef{using-enum-declarator}\br
+    \opt{nested-name-specifier} identifier\br
+    \opt{nested-name-specifier} simple-template-id
 \end{bnf}
 
 \pnum
-The \grammarterm{elaborated-enum-specifier}
-shall not name a dependent type
-and the type shall have a reachable \grammarterm{enum-specifier}.
+A \grammarterm{using-enum-declarator}
+names the set of declarations found by
+lookup\iref{basic.lookup.unqual,basic.lookup.qual}
+for the \grammarterm{using-enum-declarator}.
+The \grammarterm{using-enum-declarator}
+shall designate a non-dependent type
+with a reachable \grammarterm{enum-specifier}.
 
 \pnum
 A \grammarterm{using-enum-declaration}