> On Jul 29, 2017, at 4:33 PM, Chris Lattner <clatt...@nondot.org> wrote: >> On Jul 29, 2017, at 1:32 PM, John McCall <rjmcc...@apple.com> wrote: >> >>> On Jul 29, 2017, at 4:24 PM, Chris Lattner via swift-dev >>> <swift-dev@swift.org> wrote: >>> >>> On Jul 28, 2017, at 2:20 PM, Joe Groff via swift-dev <swift-dev@swift.org> >>> wrote: >>>> >>>> Overall, my intuition is that the tradeoffs come out in favor for >>>> nonunique metadata objects, but what do you all think? Is there anything >>>> I'm missing? >>> >>> I think your proposal makes sense, particularly when we start caring about >>> metadata/conformances for non-nominal types, which don’t have a declaration >>> location. They are a bit over the horizon right now, but we need to >>> support making tuples conform to protocols someday. Eliminating the >>> requirement for them to be uniquely emitted across the entire program would >>> make that much simpler, because otherwise you’re in the land of weak >>> symbols or something. >> >> Not really, because the conformance is presumably still declared somewhere >> in Swift and therefore has a natural unique definition point even if the >> type doesn’t. > > Ok, so you’re suggesting that the stdlib would have the “automatically > provided” conditional conformances for things like equatable, then each > module that actually uses one gets a specialization?
Well, presumably the stdlib's generic conformance would actually be usable itself, but yes, other modules could of course emit specialized witness tables if they want. John. _______________________________________________ swift-dev mailing list swift-dev@swift.org https://lists.swift.org/mailman/listinfo/swift-dev
