Unknowndefault -

: Like a regular default , it matches any value not explicitly covered by other cases.

In Swift, every switch statement must be exhaustive. While a standard default case acts as a "catch-all" and satisfies this requirement, it can hide errors if you accidentally forget to handle a new, known case. solves this by: unknowndefault

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 : Like a regular default , it matches