Unlocking the Real Power of Swift 6’s Typed Throws with Error Chains

Discover how to turn Typed Throws from a headache into a superpower — with clean error handling and powerful debugging insights.

Swift 6 finally introduced one of the most requested features to Swift: Typed Throws. This improvement allows you to specify exactly which error types a function can throw, bringing Swift’s type safety to error handling. But with this power comes a new challenge I would call “nesting hell” — a problem that affects how errors propagate across layers of your application.

In this post, I’ll explain the nesting problem and show you how I’ve solved it in ErrorKit with a simple protocol that makes typed throws practical without boilerplate. As a bonus, you’ll see how proper error chaining can dramatically improve your debugging experience.

Typed Throws: The Promise and the Problem

First, let’s look at what Typed Throws gives us in Swift 6:

// Instead of just 'throws', we can specify the error type
func processFile() throws(FileError) {
    if !fileExists {
        throw FileError.fileNotFound(fileName: "config.json")
    }
    // Implementation...
}