Re: [swift-dev] New warning message while switching on an enum

2017-05-09 Thread Jordan Rose via swift-dev 
I think they'll all be IsPatterns, which means you can look at the 
CheckedCastKind.

Jordan


> On May 9, 2017, at 13:54, Robert Widmann  wrote:
> 
> Is there a catch-all to query for such casts (sorry, I'm away from my 
> computer at the moment).
> 
> ~Robert Widmann
> 
> 2017/05/09 16:40、Jordan Rose  > のメッセージ:
> 
>> I think any bridging conversion or upcast would count.
>> 
>> enum Foo {
>>   case foo(NSFileManager)
>>   case bar(NSString)
>>   case baz(Int)
>> }
>> func test(x: Foo) {
>>   switch x {
>>   case .foo(let obj as NSObject):
>> print("totally legal")
>>   case .bar(let obj as String):
>> print("also cool")
>>   case .baz(let obj as Any):
>> print("I'm not sure why, but sure")
>>   }
>> }
>> 
>> Jordan
>> 
>>> On May 9, 2017, at 11:29, Robert Widmann >> > wrote:
>>> 
>>> Right.  I guess I should have asked: Are there any other kinds of patterns 
>>> we consider exhaustive that have this structure?  
>>> 
>>> ~Robert Widmann
>>> 
 On May 9, 2017, at 2:23 PM, Jordan Rose > wrote:
 
 "as NSError" isn't a tautology, though—the original type is 'Error'. 
 Additionally, the presence or absence of a warning shouldn't affect 
 exhaustiveness analysis, which is currently an error when you get it 
 wrong. Warnings are things you can build with and fix later.
 
 Jordan
 
 
> On May 9, 2017, at 11:22, Robert Widmann  > wrote:
> 
> We’ll warn if that kind of cast is a tautology, right?  That leaves only 
> the dynamic casts, which can’t be assumed exhaustive.
> 
> ~Robert Widmann
> 
>> On May 9, 2017, at 2:13 PM, Jordan Rose > > wrote:
>> 
>> It's neither a variable binding nor an expression pattern, right? It has 
>> to be compared against the original type to know whether it's exhaustive 
>> or not. (Consider "let error as NSError" in a catch clause, which should 
>> be considered exhaustive.)
>> 
>> Jordan
>> 
>>> On May 9, 2017, at 11:12, Robert Widmann >> > wrote:
>>> 
>>> It’s mine, yep.  It looks like it’s classifying the cast in the first 
>>> pattern as a variable binding instead of an expression pattern.  I’ll 
>>> push a fix later.
>>> 
>>> Thanks!
>>> 
 On May 9, 2017, at 1:52 PM, Jordan Rose > wrote:
 
 That looks like a bug to me, since of course the first pattern won't 
 always match. I suspect this is Robert's work on trying to make the 
 exhaustive checks better, https://github.com/apple/swift/pull/8908 
 . Thanks for catching this!
 
 Jordan
 
 
> On May 9, 2017, at 07:09, Pushkar N Kulkarni via swift-dev 
> > wrote:
> 
> Hi there, 
> 
> I see a new warning message for switch statements on enums, like this 
> one: 
> 
> enum Test {
> case one(Any)
> case two
> }
> 
> let x: Test = .one("One")
> switch x {
> case .one(let s as String): print(s)
> case .one: break
> case .two: break
> }
> 
> enum.swift:9:10: warning: case is already handled by previous 
> patterns; consider removing it
> case .one: break 
> 
> 
> I do not see this warning with the 04-24 dev snapshot. 
> 
> The warning goes away with the use of the wildcard pattern in the 
> second case:
> 
> switch x {
> case .one(let s as String): print(s)
> case .one(_): break
> case .two: break
> }
> 
> 
> I am wondering if this change is intentional, though it does make 
> sense to me. Can someone please point me to the related commit?
> 
> Thanks in advance!
> 
> Pushkar N Kulkarni,
> IBM Runtimes
> 
> Simplicity is prerequisite for reliability - Edsger W. Dijkstra
> 
> 
> ___
> swift-dev mailing list
> swift-dev@swift.org 
> https://lists.swift.org/mailman/listinfo/swift-dev 
> 
 
>>> 
>> 
> 
 
>>> 
>> 

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Re: [swift-dev] New warning message while switching on an enum

2017-05-09 Thread Robert Widmann via swift-dev 
Is there a catch-all to query for such casts (sorry, I'm away from my computer 
at the moment).

~Robert Widmann

2017/05/09 16:40、Jordan Rose  のメッセージ:

> I think any bridging conversion or upcast would count.
> 
> enum Foo {
>   case foo(NSFileManager)
>   case bar(NSString)
>   case baz(Int)
> }
> func test(x: Foo) {
>   switch x {
>   case .foo(let obj as NSObject):
> print("totally legal")
>   case .bar(let obj as String):
> print("also cool")
>   case .baz(let obj as Any):
> print("I'm not sure why, but sure")
>   }
> }
> 
> Jordan
> 
>> On May 9, 2017, at 11:29, Robert Widmann  wrote:
>> 
>> Right.  I guess I should have asked: Are there any other kinds of patterns 
>> we consider exhaustive that have this structure?  
>> 
>> ~Robert Widmann
>> 
>>> On May 9, 2017, at 2:23 PM, Jordan Rose  wrote:
>>> 
>>> "as NSError" isn't a tautology, though―the original type is 'Error'. 
>>> Additionally, the presence or absence of a warning shouldn't affect 
>>> exhaustiveness analysis, which is currently an error when you get it wrong. 
>>> Warnings are things you can build with and fix later.
>>> 
>>> Jordan
>>> 
>>> 
 On May 9, 2017, at 11:22, Robert Widmann  wrote:
 
 We’ll warn if that kind of cast is a tautology, right?  That leaves only 
 the dynamic casts, which can’t be assumed exhaustive.
 
 ~Robert Widmann
 
> On May 9, 2017, at 2:13 PM, Jordan Rose  wrote:
> 
> It's neither a variable binding nor an expression pattern, right? It has 
> to be compared against the original type to know whether it's exhaustive 
> or not. (Consider "let error as NSError" in a catch clause, which should 
> be considered exhaustive.)
> 
> Jordan
> 
>> On May 9, 2017, at 11:12, Robert Widmann  
>> wrote:
>> 
>> It’s mine, yep.  It looks like it’s classifying the cast in the first 
>> pattern as a variable binding instead of an expression pattern.  I’ll 
>> push a fix later.
>> 
>> Thanks!
>> 
>>> On May 9, 2017, at 1:52 PM, Jordan Rose  wrote:
>>> 
>>> That looks like a bug to me, since of course the first pattern won't 
>>> always match. I suspect this is Robert's work on trying to make the 
>>> exhaustive checks better, https://github.com/apple/swift/pull/8908. 
>>> Thanks for catching this!
>>> 
>>> Jordan
>>> 
>>> 
 On May 9, 2017, at 07:09, Pushkar N Kulkarni via swift-dev 
  wrote:
 
 Hi there, 
 
 I see a new warning message for switch statements on enums, like this 
 one: 
 
 enum Test {
 case one(Any)
 case two
 }
 
 let x: Test = .one("One")
 switch x {
 case .one(let s as String): print(s)
 case .one: break
 case .two: break
 }
 
 enum.swift:9:10: warning: case is already handled by previous 
 patterns; consider removing it
 case .one: break 
 
 
 I do not see this warning with the 04-24 dev snapshot. 
 
 The warning goes away with the use of the wildcard pattern in the 
 second case:
 
 switch x {
 case .one(let s as String): print(s)
 case .one(_): break
 case .two: break
 }
 
 
 I am wondering if this change is intentional, though it does make 
 sense to me. Can someone please point me to the related commit?
 
 Thanks in advance!
 
 Pushkar N Kulkarni,
 IBM Runtimes
 
 Simplicity is prerequisite for reliability - Edsger W. Dijkstra
 
 
 ___
 swift-dev mailing list
 swift-dev@swift.org
 https://lists.swift.org/mailman/listinfo/swift-dev
>>> 
>> 
> 
 
>>> 
>> 
> 
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Re: [swift-dev] New warning message while switching on an enum

2017-05-09 Thread Robert Widmann via swift-dev 
We’ll warn if that kind of cast is a tautology, right?  That leaves only the 
dynamic casts, which can’t be assumed exhaustive.

~Robert Widmann

> On May 9, 2017, at 2:13 PM, Jordan Rose  wrote:
> 
> It's neither a variable binding nor an expression pattern, right? It has to 
> be compared against the original type to know whether it's exhaustive or not. 
> (Consider "let error as NSError" in a catch clause, which should be 
> considered exhaustive.)
> 
> Jordan
> 
>> On May 9, 2017, at 11:12, Robert Widmann > > wrote:
>> 
>> It’s mine, yep.  It looks like it’s classifying the cast in the first 
>> pattern as a variable binding instead of an expression pattern.  I’ll push a 
>> fix later.
>> 
>> Thanks!
>> 
>>> On May 9, 2017, at 1:52 PM, Jordan Rose >> > wrote:
>>> 
>>> That looks like a bug to me, since of course the first pattern won't always 
>>> match. I suspect this is Robert's work on trying to make the exhaustive 
>>> checks better, https://github.com/apple/swift/pull/8908 
>>> . Thanks for catching this!
>>> 
>>> Jordan
>>> 
>>> 
 On May 9, 2017, at 07:09, Pushkar N Kulkarni via swift-dev 
 > wrote:
 
 Hi there, 
 
 I see a new warning message for switch statements on enums, like this one: 
 
 enum Test {
 case one(Any)
 case two
 }
 
 let x: Test = .one("One")
 switch x {
 case .one(let s as String): print(s)
 case .one: break
 case .two: break
 }
 
 enum.swift:9:10: warning: case is already handled by previous patterns; 
 consider removing it
 case .one: break 
 
 
 I do not see this warning with the 04-24 dev snapshot. 
 
 The warning goes away with the use of the wildcard pattern in the second 
 case:
 
 switch x {
 case .one(let s as String): print(s)
 case .one(_): break
 case .two: break
 }
 
 
 I am wondering if this change is intentional, though it does make sense to 
 me. Can someone please point me to the related commit?
 
 Thanks in advance!
 
 Pushkar N Kulkarni,
 IBM Runtimes
 
 Simplicity is prerequisite for reliability - Edsger W. Dijkstra
 
 
 ___
 swift-dev mailing list
 swift-dev@swift.org 
 https://lists.swift.org/mailman/listinfo/swift-dev 
 
>>> 
>> 
> 

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Re: [swift-dev] New warning message while switching on an enum

2017-05-09 Thread Jordan Rose via swift-dev 
It's neither a variable binding nor an expression pattern, right? It has to be 
compared against the original type to know whether it's exhaustive or not. 
(Consider "let error as NSError" in a catch clause, which should be considered 
exhaustive.)

Jordan

> On May 9, 2017, at 11:12, Robert Widmann  wrote:
> 
> It’s mine, yep.  It looks like it’s classifying the cast in the first pattern 
> as a variable binding instead of an expression pattern.  I’ll push a fix 
> later.
> 
> Thanks!
> 
>> On May 9, 2017, at 1:52 PM, Jordan Rose > > wrote:
>> 
>> That looks like a bug to me, since of course the first pattern won't always 
>> match. I suspect this is Robert's work on trying to make the exhaustive 
>> checks better, https://github.com/apple/swift/pull/8908 
>> . Thanks for catching this!
>> 
>> Jordan
>> 
>> 
>>> On May 9, 2017, at 07:09, Pushkar N Kulkarni via swift-dev 
>>> > wrote:
>>> 
>>> Hi there, 
>>> 
>>> I see a new warning message for switch statements on enums, like this one: 
>>> 
>>> enum Test {
>>> case one(Any)
>>> case two
>>> }
>>> 
>>> let x: Test = .one("One")
>>> switch x {
>>> case .one(let s as String): print(s)
>>> case .one: break
>>> case .two: break
>>> }
>>> 
>>> enum.swift:9:10: warning: case is already handled by previous patterns; 
>>> consider removing it
>>> case .one: break 
>>> 
>>> 
>>> I do not see this warning with the 04-24 dev snapshot. 
>>> 
>>> The warning goes away with the use of the wildcard pattern in the second 
>>> case:
>>> 
>>> switch x {
>>> case .one(let s as String): print(s)
>>> case .one(_): break
>>> case .two: break
>>> }
>>> 
>>> 
>>> I am wondering if this change is intentional, though it does make sense to 
>>> me. Can someone please point me to the related commit?
>>> 
>>> Thanks in advance!
>>> 
>>> Pushkar N Kulkarni,
>>> IBM Runtimes
>>> 
>>> Simplicity is prerequisite for reliability - Edsger W. Dijkstra
>>> 
>>> 
>>> ___
>>> swift-dev mailing list
>>> swift-dev@swift.org 
>>> https://lists.swift.org/mailman/listinfo/swift-dev 
>>> 
>> 
> 

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Re: [swift-dev] New warning message while switching on an enum

2017-05-09 Thread Robert Widmann via swift-dev 
It’s mine, yep.  It looks like it’s classifying the cast in the first pattern 
as a variable binding instead of an expression pattern.  I’ll push a fix later.

Thanks!

> On May 9, 2017, at 1:52 PM, Jordan Rose  wrote:
> 
> That looks like a bug to me, since of course the first pattern won't always 
> match. I suspect this is Robert's work on trying to make the exhaustive 
> checks better, https://github.com/apple/swift/pull/8908 
> . Thanks for catching this!
> 
> Jordan
> 
> 
>> On May 9, 2017, at 07:09, Pushkar N Kulkarni via swift-dev 
>> > wrote:
>> 
>> Hi there, 
>> 
>> I see a new warning message for switch statements on enums, like this one: 
>> 
>> enum Test {
>> case one(Any)
>> case two
>> }
>> 
>> let x: Test = .one("One")
>> switch x {
>> case .one(let s as String): print(s)
>> case .one: break
>> case .two: break
>> }
>> 
>> enum.swift:9:10: warning: case is already handled by previous patterns; 
>> consider removing it
>> case .one: break 
>> 
>> 
>> I do not see this warning with the 04-24 dev snapshot. 
>> 
>> The warning goes away with the use of the wildcard pattern in the second 
>> case:
>> 
>> switch x {
>> case .one(let s as String): print(s)
>> case .one(_): break
>> case .two: break
>> }
>> 
>> 
>> I am wondering if this change is intentional, though it does make sense to 
>> me. Can someone please point me to the related commit?
>> 
>> Thanks in advance!
>> 
>> Pushkar N Kulkarni,
>> IBM Runtimes
>> 
>> Simplicity is prerequisite for reliability - Edsger W. Dijkstra
>> 
>> 
>> ___
>> swift-dev mailing list
>> swift-dev@swift.org 
>> https://lists.swift.org/mailman/listinfo/swift-dev
> 

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Re: [swift-dev] New warning message while switching on an enum

2017-05-09 Thread Jordan Rose via swift-dev 
That looks like a bug to me, since of course the first pattern won't always 
match. I suspect this is Robert's work on trying to make the exhaustive checks 
better, https://github.com/apple/swift/pull/8908 
. Thanks for catching this!

Jordan


> On May 9, 2017, at 07:09, Pushkar N Kulkarni via swift-dev 
>  wrote:
> 
> Hi there, 
> 
> I see a new warning message for switch statements on enums, like this one: 
> 
> enum Test {
> case one(Any)
> case two
> }
> 
> let x: Test = .one("One")
> switch x {
> case .one(let s as String): print(s)
> case .one: break
> case .two: break
> }
> 
> enum.swift:9:10: warning: case is already handled by previous patterns; 
> consider removing it
> case .one: break 
> 
> 
> I do not see this warning with the 04-24 dev snapshot. 
> 
> The warning goes away with the use of the wildcard pattern in the second case:
> 
> switch x {
> case .one(let s as String): print(s)
> case .one(_): break
> case .two: break
> }
> 
> 
> I am wondering if this change is intentional, though it does make sense to 
> me. Can someone please point me to the related commit?
> 
> Thanks in advance!
> 
> Pushkar N Kulkarni,
> IBM Runtimes
> 
> Simplicity is prerequisite for reliability - Edsger W. Dijkstra
> 
> 
> ___
> swift-dev mailing list
> swift-dev@swift.org
> https://lists.swift.org/mailman/listinfo/swift-dev

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[swift-dev] New warning message while switching on an enum

2017-05-09 Thread Pushkar N Kulkarni via swift-dev 
Hi there, I see a new warning message for switch statements on enums, like this one: enum Test {    case one(Any)    case two}let x: Test = .one("One")switch x {    case .one(let s as String): print(s)    case .one: break    case .two: break}enum.swift:9:10: warning: case is already handled by previous patterns; consider removing it    case .one: break I do not see this warning with the 04-24 dev snapshot. The warning goes away with the use of the wildcard pattern in the second case:switch x {    case .one(let s as String): print(s)    case .one(_): break    case .two: break}I am wondering if this change is intentional, though it does make sense to me. Can someone please point me to the related commit?Thanks in advance!Pushkar N Kulkarni,
IBM RuntimesSimplicity is prerequisite for reliability - Edsger W. Dijkstra


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