> On Mar 16, 2016, at 5:27 PM, Alex Martini via swift-evolution > <swift-evolution@swift.org> wrote: > > To help keep proposals moving forward, the Swift core team has set aside some > time specifically for design discussions of upcoming proposals. Below are > some rough notes from the yesterday's discussion. > > These are informal comments, intended to guide the proposals in directions > that draw constructive feedback. You are welcome to ignore the feedback, > agree with it, or disagree with it. As always, the formal decision doesn't > happen until after the review period ends. > > SE-0048 > <file:///Users/alexmartini/DevPubs%20Git%20Repositories/Swift%20Language%20Review/_build/html/LR_MeetingNotes/MeetingNotes-03-15-2016.html#se-0048> > This is straightforward and 95% implemented. The contentious point is that it > starts simple: you can’t add constraints to the type alias. > > We want to avoid type-based metaprogramming. > > Unclear if this would work: > > typealias StringDictionary<T> = Dictionary<String, T> > It need to infer that T must be hashable. Maybe it’s only 85% implemented. > >
Clarification here: the example is typealias DictionaryToStrings<T> = Dictionary<T, String> Either we infer T to require Hashable, or we call this ill-formed and require the user to write typealias DictionaryToStrings<T: Hashable> = Dictionary<T, String> - Doug
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