enum SomeError : ErrorType {
  case Error
}

enum SomethingOrError<T> {
  case err(SomeError)
  case some(T)
}

func doit() -> SomethingOrError<Int> {
  return SomethingOrError.some(0)
}

func doit() throws -> Int {
  return 0
}

let something = try! doit()

t.swift:18:22: error: ambiguous use of 'doit()'
let something = try! doit()
                     ^
t.swift:10:6: note: found this candidate
func doit() -> SomethingOrError<Int> {
     ^
t.swift:14:6: note: found this candidate
func doit() throws -> Int {
     ^