Sema: keep FinalAttr in decl->getAttrs for print order compatibility

Author: xymus

lib/AST/TypeCheckRequests.cpp

@@ -248,6 +248,10 @@ void IsFinalRequest::cacheResult(bool value) const {
   auto decl = std::get<0>(getStorage());
   decl->LazySemanticInfo.isFinalComputed = true;
   decl->LazySemanticInfo.isFinal = value;
+
+  // Register Final in attributes, to preserve print order
+  if (value && !decl->getAttrs().hasAttribute<FinalAttr>())
+    decl->getAttrs().add(new (decl->getASTContext()) FinalAttr(/*Implicit=*/true));
 }
 
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