On Wed, May 24, 2017 at 12:57 PM, Tony Parker <[email protected]> wrote:
> > > On May 24, 2017, at 12:51 PM, Pavel Yaskevich <[email protected]> > wrote: > > Hi Tony, > > On Wed, May 24, 2017 at 12:37 PM, Jose Cheyo Jimenez via swift-evolution < > [email protected]> wrote: > >> The way I interpreted SE-110 is that it was suppose to address anonymous >> arguments. >> >> Instead of using $0.0, $0.1, One needs to use $0, $1 when there are >> multiple arguments. >> >> I was not aware of any implications for explicitly named parameters. >> >> Perhaps the issue is with the signature of forEach. Does it need to be a >> nested tuple? >> >> public func forEach(_ body: ((key: Key, value: >> Value)) throws -> Void) rethrows >> > > Jose is right about this one, since the signature of forEach is a tuple > nested into paren it means that `forEach` expects a single argument > of a tuple type instead of two arguments, such "tuple argument > destructuring" was supported by Swift 3 but after SE-0110 no longer is > because type-checker is preserving top level parens in > parameters/arguments. > > Best Regards, Pavel. > > > Well, frankly, I don’t think we should ship with such a glaring usability > regression. > > What’s the mitigation plan? Perhaps we should wholesale revert it until we > have time to reconsider the fallout? > There is a migrator support, and I've made a couple of diagnostic improvements for it, that produce fix-its which are exactly what you see in the aforementioned PR. Otherwise, I'd defer to Slava, who was implementor of SE-0110. > > - Tony > > > >> >> >> On May 24, 2017, at 12:12 PM, Tony Parker via swift-evolution < >> [email protected]> wrote: >> >> Hi everyone, >> >> We received a pull request in swift-corelibs-foundation which is >> apparently in response to a language change for SE-0110. >> >> It turns this perfectly reasonable code: >> >> - self.forEach { (keyItem, valueItem) in >> >> into this: >> >> >> + self.forEach { (arg) in >> + let (keyItem, valueItem) = arg >> >> Is that really the design pattern we want to encourage? What was wrong >> with the previous code? >> >> (https://github.com/apple/swift-corelibs-foundation/pull/995/files) >> >> - Tony >> >> _______________________________________________ >> swift-evolution mailing list >> [email protected] >> https://lists.swift.org/mailman/listinfo/swift-evolution >> >> >> >> _______________________________________________ >> swift-evolution mailing list >> [email protected] >> https://lists.swift.org/mailman/listinfo/swift-evolution > > >
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