[swift-evolution] guard let x = x

[Jeremy Pereira]

> On 29 Oct 2016, at 02:10, Erica Sadun via swift-evolution <swift-evolution at swift.org> wrote:
> 
> Sounds good to me. Leaving the gist in its updated state (a little further from the last time) for the record.

I like the first part, even though I disagree that `if let foo = foo` conflicts with DRY principles. However, I think you should drop the part about unwrapping enums for now. That looks like a whole can of worms with a zillion edge cases and could be dangerous in the wrong hands:

@unwrappable(type: String)
public enum Result
{
    case success(String) // String is the data requested
    case error(String) // String is an error message
}

func getTheResult() -> Result { … }
….

if unwrap getTheResult() 
{
	// Here we put the code for the success case - or do we?
}

In the above, the code that uses unwrap would be broken simply by reordering the cases in the enum declaration and not in a good way. There would be no compilation or runtime error, an error message would simply be treated as normal data. 

Having code depend on the order of something somewhere else - not necessarily even in the same module doesn’t seem very Swifty to me.