Responding on the pro side, but I don't endorse this proposal without more
2017/01/25 13:40、Xiaodi Wu <email@example.com> のメッセージ:
This is contrary to several deliberate design decisions, if I understand
First, revisions to visibility rules in the Swift 3 timeline were made
with the deliberate intention that it should be possible to model greater
visibility within a type (e.g. public members) without actually exporting
that type. As Swift does not have optional warnings that can be turned off,
it would be incongruous if the language also warned users away from
creating internal types or variables before they are used. Unlike warnings
about unused variables within a scope, which are by definition local, a
warning such as proposed would be much more disruptive.
That decision wasn't really one made to support a deliberate design, but
to help make migration of fileprivate easier IIRC (Jordan Rose probably
remembers better than I do of the conversation we had about this).
It's important to note we already provide module-wide warnings (namely if
we detect you mutating a let-bound member we offer a fixit at the site of
the member decl) so this isn't new.
Second, a variable with no access modifier defaults to internal, and this
is deliberate for the purpose of progressive disclosure (i.e. it is, by
design, possible for a new user to write useful code separated across
multiple files without learning what access modifiers are). This would be
undone if nearly every such use prompted a warning.
That enforces hiding from clients, OP wants to enforce a model where we
enforce data hiding from yourself as well. If a variable's access needs to
be escalated we can provide that fixit as well (instead of the current
errors we offer now which are usually spurious type errors because lookup
Sure, the motivation is not ambiguous.
In the past, when new syntax for yet another access level has been
proposed, I've argued that perfect data hiding from yourself (as opposed to
clients) has been a non-goal (given the access levels available today) and
probably should continue to be. There's been disagreement about that--fine.
But _enforcing_ data hiding from yourself as The One True Way of Swift is
something else. Though not technically *source* breaking for existing code,
it is certainly radically design breaking. Far from being a bugfix, I'd
argue that such a change is big enough to merit one of those
manifesto-style big-picture discussions, and I'd want to be convinced of
huge wins for such a U-turn in direction.
In summary, I think the issue here is more one of style than safety, and
On Wed, Jan 25, 2017 at 4:34 PM, Robert Widmann <firstname.lastname@example.org> wrote:
IMO is more within the scope of a linter.
On Wed, Jan 25, 2017 at 12:27 Robert Widmann via swift-evolution < > email@example.com> wrote:
So, to be clear, a warning about making internal variables more private
based on their usage in the entire module?
Sounds doable. Probably wouldn't need to go through evolution to get it
too (but I'll let others make that call). Please file an SR about this too.
2017/01/25 3:25、Dave Kliman via swift-evolution <
I’m somewhat new to swift, so this issue may have been covered.
I really like how I get a warning for variables I’ve declared, but have
not mutated, or constants that I did not read.
What about warnings for anything not accessed outside its declared scope,
encouraging the use of *private*, or *fileprivate* more often?
swift-evolution mailing list
swift-evolution mailing list