[clang] No longer add enumeration constants to the wrong scope (PR #134998)

[Erich Keane via cfe-commits]

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@@ -1523,7 +1523,10 @@ void Sema::PushOnScopeChains(NamedDecl *D, Scope *S, bool AddToContext) {
 
   // Out-of-line definitions shouldn't be pushed into scope in C++, unless they
   // are function-local declarations.
-  if (getLangOpts().CPlusPlus && D->isOutOfLine() && !S->getFnParent())
+  bool OutOfLine = D->isOutOfLine();
+  if (const auto *ECD = dyn_cast<EnumConstantDecl>(D))
+    OutOfLine = OutOfLine || cast<Decl>(ECD->getDeclContext())->isOutOfLine();
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erichkeane wrote:

Hmm... What is the logic to set the `EnumConstantDecl` (or, that is, just the `Decls` themselves) to be `OutOfLine`? I can't imagine this is the only logic for `OutOfLine` that could be reasonable to check, and wonder if we should just set `EnumConstantDecl::OutOfLine` 'correctly'.

WDYT?

https://github.com/llvm/llvm-project/pull/134998