[interop][SwiftToCxx] workaround windows failure with Error new use in SwiftToCxxToSwift/hide-swift-module-namespace-in-swift.swift

Author: hyp

lib/PrintAsClang/_SwiftStdlibCxxOverlay.h

@@ -132,6 +132,8 @@ inline const void *_Nullable getErrorMetadata() {
   return ptr2;
 }
 
+#ifndef SWIFT_CXX_INTEROP_HIDE_SWIFT_ERROR
+
 class Error {
 public:
   Error() {}
@@ -369,4 +371,6 @@ using ThrowingResult = Swift::Expected<T>;
 
 #endif
 
+#endif // SWIFT_CXX_INTEROP_HIDE_SWIFT_ERROR
+
 #endif

test/Interop/SwiftToCxxToSwift/hide-swift-module-namespace-in-swift.swift

@@ -5,7 +5,7 @@
 
 // RUN: %FileCheck %s < %t/swiftMod.h
 
-// RUN: %target-swift-frontend -typecheck %t/swiftMod.swift -typecheck -module-name SwiftMod -emit-clang-header-path %t/swiftMod2.h -I %t -enable-experimental-cxx-interop
+// RUN: %target-swift-frontend -typecheck %t/swiftMod.swift -typecheck -module-name SwiftMod -emit-clang-header-path %t/swiftMod2.h -I %t -enable-experimental-cxx-interop -Xcc -DSWIFT_CXX_INTEROP_HIDE_SWIFT_ERROR
 
 // RUN: %check-interop-cxx-header-in-clang(%t/swiftMod2.h -DSWIFT_CXX_INTEROP_HIDE_STL_OVERLAY  -Wno-error)