> On Jun 6, 2017, at 12:08 AM, Jens Persson via swift-evolution
> <[email protected]> wrote:
>
> IMHO There seems to be a lot of bugs and inconsistencies left in more than
> just the reflective type system, for example the following won't compile
> although the two foo funcs clearly take different types as argument:
>
> func foo(fun: (Int, Int) -> ()) { print("was given a function of type: (Int,
> Int) -> ()") }
> func foo(fun: ((Int, Int)) -> ()) { print("was given a function of type:
> ((Int, Int)) -> ()") }
I took a look at this. When determining if we have conflicting declarations, we
compute an interface type and this computation is stripping the parens around
the tuple in the second example, resulting in these two signatures appearing to
be the same, despite the fact that the types of the arguments to the two
functions are different.
> // This will result in error: invalid redeclaration of 'foo(fun:)'
>
> I would expect this to compile, and I can't understand how this has anything
> to do with the reflective type system.
>
>
> Here is another example:
>
> func add(_ a: Int, _ b: Int) -> Int { return a + b }
> let a: (Int, Int) -> Int = add
> let b: ((Int, Int)) -> Int = add // This is OK, unexpectedly
I didn’t have a chance to look at this yet. I suspect this is related to the
swap example that you gave previously.
> I would not expect it to compile since the add func does not have the type
> ((Int, Int)) -> Int.
> I don't think that is a dynamic cast, is it?
Would you mind opening bugs for all four issues - the two mentioned above and
the two from the previous e-mail (with type(of:) and swap examples)? Despite
the fact that some of these might have different underlying causes it would be
useful to have separate bugs and if they turn out to be the same issue we can
dup as appropriate.
Mark
>
> /Jens
>
>
>
>
> On Tue, Jun 6, 2017 at 2:45 AM, John McCall <[email protected]
> <mailto:[email protected]>> wrote:
>> On Jun 5, 2017, at 12:08 AM, Jens Persson via swift-evolution
>> <[email protected] <mailto:[email protected]>> wrote:
>> So the bug in the reflective type system needs to be fixed before SE-0110
>> can actually be implemented (so that the statements in its title and text
>> are true when compared to the actual behavior of the current Swift 4
>> compiler),
>
> Gaps in the reflective type system are bugs, but they are not showstopper
> bugs. We do not even expose any way to query the reflective system today; it
> basically only affects type equality and dynamic casts that programmers are
> very unlikely to use. The changes in call type-checking are vastly more
> important, are implemented (modulo bugs, of course), and by themselves
> warrant calling SE-0110 implemented.
>
> John.
>
>>
>> And yet:
>>
>> 1. The status of SE-0110 is "Implemented"
>>
>> 2. These statuses of the following issues are "resolved":
>> SR-2008: Distinguish between single-tuple and multiple-argument function
>> types
>> SR-2216: Confusing behavior related to closure types and tuples
>> SR-296: Fix inconsistencies related to tuples, arg/param lists, type
>> params, typealiases
>>
>> Why?
>>
>> /Jens
>>
>>
>> On Sun, Jun 4, 2017 at 5:49 PM, Ben Rimmington <[email protected]
>> <mailto:[email protected]>> wrote:
>> I assumed that Swift 3 mode would be the default, so that existing
>> `#!/usr/bin/swift` scripts continue to work.
>>
>> -- Ben
>>
>> > On 3 Jun 2017, at 23:47, Jens Persson <[email protected]
>> > <mailto:[email protected]>> wrote:
>> >
>> > Yes of course, try my demonstration code yourself.
>> > (In the current dev snapshots, -swift-version 4 is the default and
>> > -swift-version 3 is what you need to set if you want 3 compability)
>> >
>> >> On Sun, Jun 4, 2017 at 12:37 AM, Ben Rimmington <[email protected]
>> >> <mailto:[email protected]>> wrote:
>> >>
>> >> Are you using the Swift 4 language mode?
>> >>
>> >> <https://swift.org/blog/swift-4-0-release-process/#source-compatibility
>> >> <https://swift.org/blog/swift-4-0-release-process/#source-compatibility>>
>> >>
>> >> -- Ben
>>
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