// MultiStack returns the best possible stack.Multi from the error or nil if // one isn't found. func MultiStack(err error) *stack.Multi { switch err := err.(type) { case *singleFrameError: var m stack.Multi m.Add(stack.Stack{err.frame}) return &m case *singleStackError: var m stack.Multi m.Add(err.stack) return &m case *multiStackError: return err.multiStack } return nil }