Untyped throws (UntypedThrows)

A Swift function can declare that it can throw an error using throws, optionally providing a specific thrown error type:

func canThrowAnything() throws { ... }          // untyped throws
func canThrowMyError() throws(MyError) { ... }  // typed throws (only throws MyError)

When a specific thrown error type is omitted, any Error will be used instead. Throwing an error of type any Error involves a heap allocation as well as reference-counting overhead. Therefore, highly performance-sensitive code should prefer to use typed throws over untyped throws.

See Also

• SE-0413: Typed Throws