> On Jun 7, 2016, at 3:12 PM, Xiaodi Wu <xiaodi...@gmail.com> wrote: > > On Tue, Jun 7, 2016 at 2:49 PM, Michael Peternell via swift-evolution > <swift-evolution@swift.org <mailto:swift-evolution@swift.org>> wrote: > > > Am 07.06.2016 um 19:45 schrieb Charles Srstka via swift-evolution > > <swift-evolution@swift.org <mailto:swift-evolution@swift.org>>: > > > >> On Jun 7, 2016, at 11:47 AM, Brent Royal-Gordon via swift-evolution > >> <swift-evolution@swift.org <mailto:swift-evolution@swift.org>> wrote: > >> > >>> I disagree. We are discussing how to annotate a function in some way so > >>> that the compiler knows that the code following it will never be executed > >>> *and* so a human who reads the declaration knows that it does not return. > >>> “Never" is a poor choice for that. Never what? Never return? Never use > >>> this function? Never say never again? > >> > >> "Never return". That's why it's in the return type slot, right after the > >> `->`. If you read it out loud, you'll read "returns Never", which is > >> exactly correct. > >> > >> NoReturn, on the other hand, does *not* read well in that slot: "returns > >> NoReturn". Huh? I mean, I suppose you won't misunderstand it, but it makes > >> no sense whatsoever *as a type name*. > > > > But it’s *not* a type. You’ll never have an instance of it. > > That's the dictionary definition of a bottom type > <https://en.wikipedia.org/wiki/Bottom_type>, though: a type which has no > values. > > Since it’s not a type name, it doesn’t make sense that it needs to look like > one. What it is doing is telling you something about the behavior of the > function itself, not its return value. Its return value, if there were one, > is irrelevant, since the function, by its very nature, will never even get to > the point where it would return it. > > And that's the dictionary definition of a function where the return type is > bottom. This isn't something being made up just for Swift...
What’s the dictionary definition of a do loop? Or a for loop? Or try/catch? Swift doesn’t do things the same as other languages in lots of places. I don’t see why it has to be different here. @noreturn is a clearer description of what this construct does. Charles
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