[swift-evolution] [Accepted] SE-0072: Fully eliminate implicit bridging conversions from Swift

[Joe Groff]

> On May 6, 2016, at 8:20 PM, Charles Srstka <cocoadev at charlessoft.com> wrote:
> 
>> On May 6, 2016, at 3:15 PM, Joe Groff via swift-evolution <swift-evolution at swift.org> wrote:
>> 
>>> On May 6, 2016, at 12:21 PM, Jacob Bandes-Storch via swift-evolution <swift-evolution at swift.org> wrote:
>>> 
>>> Does this affect the ability to use "x as? Int" (and similar) when x is an NSNumber?
>> 
>> No, this only affects compile-time implicit conversions. I proposed changing the runtime behavior of dynamic casts in SE-0083:
>> 
>> https://github.com/apple/swift-evolution/blob/master/proposals/0083-remove-bridging-from-dynamic-casts.md
> 
> I’d just like to throw in that the ability to use “x as? Int” when x is an NSNumber is terrible.
> 
> let num: AnyObject = NSNumber(int: 5)
> 
> let int = num as? Int		// 5
> let float = num as? Float		// 5
> let int32 = num as? Int32	// nil!
> 
> Completely unexpected failure, and you’ll never know about it until runtime.

My pitch to eliminate this casting behavior got pulled as SE-0083, up for review this week:

https://github.com/apple/swift-evolution/blob/master/proposals/0083-remove-bridging-from-dynamic-casts.md

-Joe