How do you call an untyped throwing overload from a typed one?

[Quedlinbug]

@Slava_Pestov

Have you considered adding a case (with payload) to FunctionsError to wrap the closure's error in, instead of going all the way to throwing an any Error?

Yes. I think there's room for the language to support such unions better in the future—people have some good ideas about them—perhaps if Never as associated values made cases not need to be checked…? I don’t see a related solution at present. FunctionsError can’t actually be assumed to be tied to the function, or a closure.

@Slava_Pestov

func f(_: () throws(InnerError) -> ()) throws -> () { print("any Error overload") }

That's …one error type? That overload has to account for all errors that are not Never, not one specific type in particular.