[clang] [Clang] Add template argument support for {con,de}structor attributes. (PR #151400)

[Jordan R AW via cfe-commits]

================
@@ -2152,29 +2152,44 @@ static void handleUnusedAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
   D->addAttr(::new (S.Context) UnusedAttr(S.Context, AL));
 }
 
+static std::optional<Expr *> sharedGetConstructorDestructorAttrExpr(Sema &S, const ParsedAttr &AL) {
----------------
ajordanr-google wrote:

I would note that there's a distinction between `getNumArgs() != 1` (`nullptr`) and the type being invalid through other means (`nullopt` here). What's the appropriate style recommendation for handling an error case here, separate from a nullptr then? An out parameter perhaps?

https://github.com/llvm/llvm-project/pull/151400