Swift Type Compatibility When you create a Swift class that descends from an Objective-C class, the class and its members—properties, methods, subscripts, and initializers—that are compatible with Objective-C are automatically available from Objective-C. This excludes Swift-only features, such as those listed here: Generics Tuples Enumerations defined in Swift without Int raw value type Structures defined in Swift Top-level functions defined in Swift Global variables defined in Swift Typealiases defined in Swift Swift-style variadics Nested types Curried functions