[clang] [Clang][Sema] Diagnose friend declarations with enum elaborated-type-specifier in all language modes (PR #80171)

[Krystian Stasiowski via cfe-commits]

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@@ -1637,10 +1637,8 @@ def err_inline_namespace_std : Error<
 def err_unexpected_friend : Error<
   "friends can only be classes or functions">;
 def ext_enum_friend : ExtWarn<
-  "befriending enumeration type %0 is a C++11 extension">, InGroup<CXX11>;
-def warn_cxx98_compat_enum_friend : Warning<
-  "befriending enumeration type %0 is incompatible with C++98">,
-  InGroup<CXX98Compat>, DefaultIgnore;
+  "elaborated enumeration type cannot be a friend">,
----------------
sdkrystian wrote:

@Endilll 
> Would it? I'd expect enumerators to have access to non-public constants.

The enumerators do not get any special access. Per [[class.friend] p3](http://eel.is/c++draft/class.friend#3):
> If the type specifier in a friend declaration designates a (possibly cv-qualified) class type, that class is declared as a friend; otherwise, the friend declaration is ignored.



https://github.com/llvm/llvm-project/pull/80171