[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:

Why do we push a `UsingEnumDecl` into the scope at all? Would it make sense for the caller to just add the declaration to the `DeclContext` instead of calling `PushOnScopeChains`?

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