[swift-evolution] Warning for possible overflow or optional

[David Turnbull]

This is perfectly safe since it's checked at runtime. If you don't want it
checked at runtime you can use Int16(bitPattern: x).

I just finished writing the inflate algorithm in Swift. With your
suggestion I would have used bitPattern or truncatingBitPattern everywhere
to bypass warnings and missed at least two times where Swift caught a
mistake a runtime. C API users would have a similar problem.

-david  https://github.com/AE9RB/SwiftGL

On Tue, Feb 16, 2016 at 4:45 AM, Stéphane Lizeray <swift-evolution at swift.org
> wrote:

> Hello,
>
>
> Don’t you think that the compiler should emit a warning for a possible
> overflow in the following code?
>
>
> func foo(x:UInt16) {
>
> let y = Int16(x) <— Shouldn’t we have a warning here? Or an optional?
> print(y)
> }
>
> This code is very very fragile and Swift is supposed to bring safety?
>
>
> Thanks,
>
>
> Stéphane
>
>
>
>
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>
>
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