From b73fd8eff7de70492e5ec819547621a5b52967cf Mon Sep 17 00:00:00 2001
From: Cassie Jones <cassie_jones@apple.com>
Date: Thu, 16 Jan 2025 15:19:23 -0800
Subject: [PATCH 1/2] [cxx-interop] Workaround compiler error when importing
 AppKit/UIKit with C++ interop

The AppKit/UIKit overlay refers to symbols declared via NS_OPTIONS
macro, which is causing issues in C++ language mode due to the macro
definition being different. This teaches the module interface loader to
drop the C++ interop flag when rebuilding the AppKit and UIKit overlay
from its interface.

This is the same fix as #78636, but for different modules.

rdar://143033209
(cherry picked from commit 7323a752b6d7124280ce1059a617b3f418f690a1)
---
 lib/Frontend/ModuleInterfaceLoader.cpp           |  5 ++++-
 .../Cxx/objc-correctness/appkit-uikit.swift      | 16 ++++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)
 create mode 100644 test/Interop/Cxx/objc-correctness/appkit-uikit.swift

diff --git a/lib/Frontend/ModuleInterfaceLoader.cpp b/lib/Frontend/ModuleInterfaceLoader.cpp
index d980c72ca6092..281b76d2feebb 100644
--- a/lib/Frontend/ModuleInterfaceLoader.cpp
+++ b/lib/Frontend/ModuleInterfaceLoader.cpp
@@ -2195,7 +2195,10 @@ InterfaceSubContextDelegateImpl::runInSubCompilerInstance(StringRef moduleName,
   // interop enabled by the Swift CI because it uses an old host SDK.
   // FIXME: Hack for CoreGraphics.swiftmodule, which cannot be rebuilt because
   // of a CF_OPTIONS bug (rdar://142762174).
-  if (moduleName == "Darwin" || moduleName == "CoreGraphics") {
+  // FIXME: Hack for AppKit.swiftmodule / UIKit.swiftmodule, which cannot be
+  // rebuilt because of an NS_OPTIONS bug (rdar://143033209)
+  if (moduleName == "Darwin" || moduleName == "CoreGraphics"
+      || moduleName == "AppKit" || moduleName == "UIKit") {
     subInvocation.getLangOptions().EnableCXXInterop = false;
     subInvocation.getLangOptions().cxxInteropCompatVersion = {};
     BuildArgs.erase(llvm::remove_if(BuildArgs,
diff --git a/test/Interop/Cxx/objc-correctness/appkit-uikit.swift b/test/Interop/Cxx/objc-correctness/appkit-uikit.swift
new file mode 100644
index 0000000000000..4bde2ab69d9ca
--- /dev/null
+++ b/test/Interop/Cxx/objc-correctness/appkit-uikit.swift
@@ -0,0 +1,16 @@
+// RUN: %target-swift-frontend -typecheck -verify -I %S/Inputs -cxx-interoperability-mode=default %s
+
+// REQUIRES: objc_interop
+// REQUIRES: VENDOR=apple
+
+#if canImport(AppKit)
+import AppKit
+
+var _: AttributeScopes.AppKitAttributes.UnderlineStyleAttribute! = nil
+
+#elseif canImport(UIKit)
+import UIKit
+
+var _: AttributeScopes.AppKitAttributes.UnderlineStyleAttribute! = nil
+
+#endif

From 4db47be6e762889c9a90c3750a3c9a5e9bdae26d Mon Sep 17 00:00:00 2001
From: Erik Eckstein <eeckstein@apple.com>
Date: Mon, 20 Jan 2025 12:38:40 +0100
Subject: [PATCH 2/2] tests: fix
 Interop/Cxx/objc-correctness/appkit-uikit.swift for iOS

(cherry picked from commit 34a68736ac6d171c78434374f8603915bb1b77f4)
---
 test/Interop/Cxx/objc-correctness/appkit-uikit.swift | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/test/Interop/Cxx/objc-correctness/appkit-uikit.swift b/test/Interop/Cxx/objc-correctness/appkit-uikit.swift
index 4bde2ab69d9ca..2569d66f97cb7 100644
--- a/test/Interop/Cxx/objc-correctness/appkit-uikit.swift
+++ b/test/Interop/Cxx/objc-correctness/appkit-uikit.swift
@@ -2,6 +2,7 @@
 
 // REQUIRES: objc_interop
 // REQUIRES: VENDOR=apple
+// REQUIRES: OS=macosx || OS=ios
 
 #if canImport(AppKit)
 import AppKit
@@ -11,6 +12,6 @@ var _: AttributeScopes.AppKitAttributes.UnderlineStyleAttribute! = nil
 #elseif canImport(UIKit)
 import UIKit
 
-var _: AttributeScopes.AppKitAttributes.UnderlineStyleAttribute! = nil
+var _: AttributeScopes.UIKitAttributes.UnderlineStyleAttribute! = nil
 
 #endif