[swift-evolution] [Pitch] Introducing the "Unwrap or Die" operator to the standard library

Xiaodi Wu xiaodi.wu at gmail.com
Tue Jun 27 12:38:41 CDT 2017

As you write, this operator becomes sugar for “?? fatalError()” once Never
becomes a true bottom type.

In the meantime, can’t the same thing be accomplished by overloading
fatalError so it’s a generic function that returns a discardable result of
type T, which in turn calls the Never-returning overload?
On Tue, Jun 27, 2017 at 12:25 Erica Sadun via swift-evolution <
swift-evolution at swift.org> wrote:

> Using an operator to provide feedback on the context of a failed unwrap
> has become a commonly implemented approach in the Swift developer
> Community. What are your thoughts about adopting this widely-used operator
> into the standard library?
> guard !lastItem.isEmpty else { return }
> let lastItem = array.last !! "Array must be non-empty"
> Details here:
> https://gist.github.com/erica/423e4b1c63b95c4c90338cdff4939a9b
> Thank you for your thoughtful feedback, -- E
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