swift

23c3d81e - [cxx-interop] Do not always treat types with user-declared copy constructor as safe

[cxx-interop] Do not always treat types with user-declared copy constructor as safe `std::set` defined `insert` method with a return type `std::pair<iterator, bool>`. This type is unsafe to use in Swift. However, it is currently treated as safe, and `insert` is not renamed to `__insertUnsafe`, because `std::pair` defines a copy constructor. Let's not treat a user-declared copy constructor as a guarantee of safety. rdar://109529750