[swift-evolution] [Discussion] A Problem With SE-0025?

[Robert Widmann]

But the proposal does not specify that and that is not how swift's access control mechanisms currently work, unfortunately.  A private aggregate must have private members, and those members are subject to private access whether annotated or not.

On top of that, you break containment this way.  A private member is not supposed to be visible outside of its current declaration.  An aggregate full of private members similarly.  You can see the aggregate, but you cannot see its members.  If we relax this, then private is no different from fileprivate and we should just stick to our current tri-valued access control system.

~Robert Widmann

2016/06/15 23:04、Jonathan Hull via swift-evolution <swift-evolution at swift.org> のメッセージ:

> My understanding of the proposal was that the unannotated properties/methods inside of a scope have the same *visibility* as their surrounding scope, or internal, whichever is less.
> 
> That is slightly different than having the same access level.  Thus:
> 
> private struct Outer {
> 	var inner:Int
> }
> 
> is different than:
> 
> private struct Outer {
> 	private var inner:Int
> }
> 
> In the first, inner is accessible precisely everywhere where Outer is accessible.  In the second, inner is only accessible within Outer itself.  It is important that we have the first behavior for unannotated inner, because there is no other way to spell it.
> 
> That is my understanding of the intent of SE-0025, even if the exact wording is confusing.
> 
> Thanks,
> Jon
> 
> P.S.  I would personally like to see unannotated properties/methods inside of a scope have the same visibility as their surrounding scope. Full stop. End of sentence.  (It seems to me like the special handling of internal is what is causing the confusion here).  That is what I would expect the behavior to be if I didn’t know.  That isn’t what was written in the proposal though...
> 
>> While implementing SE-0025 (fileprivate), I noticed an interesting bug in the proposal.  Under the implementation outlined there, any top-level structure, class, or enum declared private cannot possibly be instantiated and so cannot be used in any way.  Because of this, private top-level declarations are more often than not blown away entirely by the compiler for being unused.  It seems strange to me to allow a key language feature to act solely as a hint to the optimizer to reduce the size of your binary.  Perhaps the restrictions around private needs to be relaxed or the line between fileprivate and private needs to be investigated again by the community before inclusion in the language.
>> 
>> Thoughts?
>> 
>> ~Robert Widmann
> 
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