I guess I missed that discussion. This "feature" does more harm than good IMHO.
> On Jan 30, 2017, at 10:16 PM, Charlie Monroe via swift-evolution
> <swift-evolution@swift.org> wrote:
>
>
>> On Jan 31, 2017, at 1:03 AM, Matthew Johnson via swift-evolution
>> <swift-evolution@swift.org> wrote:
>>
>>
>>
>> Sent from my iPad
>>
>>> On Jan 30, 2017, at 5:25 PM, Slava Pestov via swift-evolution
>>> <swift-evolution@swift.org> wrote:
>>>
>>>
>>>> On Jan 30, 2017, at 2:58 PM, Daniel Duan via swift-evolution
>>>> <swift-evolution@swift.org> wrote:
>>>>
>>>> Hi all,
>>>>
>>>> Right now, expressions that evaluates to Optional<()>,
>>>> Optional<Optional<()>>… gets special treatment when it’s unused. For
>>>> example:
>>>>
>>>> func f(s: String) {}
>>>> let s: String = “”
>>>> s.map(f) // no warning here, even tho the resulting type is `Optional<()>`
>>>> and unused.
>>>>
>>>> func g() throws {}
>>>> try? g() // no warnings here neither.
>>>>
>>>> This is convenient, but encourages composing map/filter/reduce, etc with
>>>> side-effect-ful functions, which we have found a few cases of in our
>>>> production code recently. Granted, these cases could’ve been caught with
>>>> more careful code reviews. But we wouldn’t have missed them if this
>>>> “feature” didn’t exist.
>>>>
>>>> I think we should remove the special treatment so that code in the example
>>>> above would generate a warning about `()?` being unused. Users can silence
>>>> it manually by assigning the result to `_`.
>>>>
>>>> OTOH, this would undermine the convenience of `try?` when the throwing
>>>> function don’t return anything.
>>>
>>> IMHO, using ‘try?’ to ignore an error result, instead of just turning it
>>> into an optional, is an anti-pattern, and forcing users to write ‘_ = try?
>>> foo()’ might not be so bad…
>>
>> +1
>
> Isn't this how it was in Swift 2.x and the first versions of 3.0? I believe
> this was changed only recently - which I personally found as good news. In
> some cases you simply do not care about the error result since it has no
> impact if the call fails and typing "_ =" seemed like boilerplate...
>
> If I recall correctly, this was discussed here on the list and changed to the
> current behavior.
>
>
>>
>>>
>>>>
>>>> What do y’all think?
>>>>
>>>> Daniel Duan
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