[clang] [Clang][Sema] Skip checking anonymous enum in using enum declaration (PR #87144)

[Richard Smith via cfe-commits]

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@@ -1537,6 +1537,10 @@ void Sema::PushOnScopeChains(NamedDecl *D, Scope *S, bool AddToContext) {
       cast<FunctionDecl>(D)->isFunctionTemplateSpecialization())
     return;
 
+  if (isa<UsingEnumDecl>(D) && D->getDeclName().isEmpty()) {
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zygoloid wrote:

Are those useful checks? It seems surprising to me that we'd push a `using enum` declaration into scope given that it never introduces any name of its own (the enumerators are handled separately). Are we really performing checks here that we need for a named enum but that are wrong pr unnecessary for an anonymous enum?

https://github.com/llvm/llvm-project/pull/87144