This report focuses on , a feature introduced in Swift 5 to handle "non-frozen" enumerations—enums where new cases might be added in the future without breaking existing code. Core Functionality
: If your code is recompiled and there are known enum cases that you haven't explicitly handled, the compiler will issue a warning . A standard default would stay silent. Usage and Rules unknowndefault
: It is primarily used with enums from system frameworks (like CLLocationManager.authorizationStatus() ) or Objective-C enums that aren't marked as "closed". Placement : It must be the last case in a switch statement. This report focuses on , a feature introduced