Typed throws in Swift 6

Swift 6 introduces typed throws via SE-0413, letting a function declare exactly which error type it throws using throws(SomeError) syntax. This gives catch blocks the concrete error type, enabling compiler-checked exhaustive switch handling instead of casting from any Error. throws(Never) is equivalent to non-throwing, and a generic thrown type parameter can replace rethrows for pass-through cases like map, though only when the closure's error type is explicitly annotated (trailing closures still infer to any Error). The piece argues typed throws is best reserved for single-module code, generic rethrow-style functions, and embedded/dependency-free code where any Error boxing has runtime cost — because pinning a concrete error type on a public API is a source-breaking commitment if the error set ever needs to grow.

Source: https://sarunw.com/posts/typed-throws-in-swift. 8 Sync News only summarizes and links out; content copyright belongs to the authors and original sources.