[clang] [Clang][Sema] Implement approved resolution for CWG2858 (PR #88042)

[Vlad Serebrennikov via cfe-commits]

================
@@ -58,3 +58,24 @@ void B<int>::g() requires true;
 #endif
 
 } // namespace dr2847
+
+namespace dr2858 { // dr2858: 19
+
+#if __cplusplus > 202302L
+
+template<typename... Ts>
+struct A {
+  // FIXME: The nested-name-specifier in the following friend declarations are declarative,
----------------
Endilll wrote:

Doesn't this mean that we only partially implement the DR?

https://github.com/llvm/llvm-project/pull/88042