This undoes some of Joe's work in 8665342 to add a guarantee: if an
@objc convenience initializer only calls other @objc initializers that
eventually call a designated initializer, it won't result in an extra
allocation. While Objective-C /allows/ returning a different object
from an initializer than the allocation you were given, doing so
doesn't play well with some very hairy implementation details of
compiled nib files (or NSCoding archives with cyclic references in
general).
This guarantee only applies to
(1) calling `self.init`
(2) where the delegated-to initializer is @objc
because convenience initializers must do dynamic dispatch when they
delegate, and Swift only stores allocating entry points for
initializers in a class's vtable. To dynamically find an initializing
entry point, ObjC dispatch must be used instead.
(It's worth noting that this patch does NOT check that the calling
initializer is a convenience initializer when deciding whether to use
ObjC dispatch for `self.init`. If we ever add peer delegation to
designated initializers, which is totally a valid feature, that should
use static dispatch and therefore should not go through objc_msgSend.)
This change doesn't /always/ result in fewer allocations; if the
delegated-to initializer ends up returning a different object after
all, the original allocation was wasted. Objective-C has the same
problem (one of the reasons why factory methods exist for things like
NSNumber and NSArray).
We do still get most of the benefits of Joe's original change. In
particular, vtables only ever contain allocating initializer entry
points, never the initializing ones, and never /both/ (which was a
thing that could happen with 'required' before).
rdar://problem/46823518
SE-0072 took implicit bridging conversions away, which regressed the ability to express NSDictionaries as dictionary literals and index them using literal keys. Address this by changing the signature of init(dictionaryLiteral:) to use Hashable and Any, and by replacing the subscript from Objective-C with one using _Hashable that does the bridging on the user's behalf. This largely restores the QoI of working with NS collections.
One last bit of SE-0072. We shouldn't fall back to bridged classes in the absence of type context for literals anymore. By itself, this kind of hoses the use of literals with NS types, but I think we can get most of the QoI back with overlay changes I plan to propose following this.
Second pass at updates for SE-0086 feedback
<rdar://problem/26892977> Make sure NSOrderedSet keeps its NS
<rdar://problem/26880016> NSBundleResourceRequest should keep its NS
<rdar://problem/26892958> Make sure NSAttributedString keeps its NS
<rdar://problem/26653694> NSCoder.decodeTopLevelObjectForKey does not follow naming guidelines
<rdar://problem/27355801> Foundation should have a structural type for TextCheckingResult
<rdar://problem/26770611> NSExpression naming is a bit awkward in swift
<rdar://problem/26653451> NSCoder encodeDataObject is misleading
<rdar://problem/26653653> NSCoder decodeObjectOfClass is redundant
Most of this is in updating the standard library, SDK overlays, and
piles of test cases to use the new names. No surprises here, although
this shows us some potential heuristic tweaks.
There is one substantive compiler change that needs to be factored out
involving synthesizing calls to copyWithZone()/copy(zone:). Aside from
that, there are four failing tests:
Swift :: ClangModules/objc_parse.swift
Swift :: Interpreter/SDK/Foundation_test.swift
Swift :: Interpreter/SDK/archiving_generic_swift_class.swift
Swift :: Interpreter/SDK/objc_currying.swift
due to two independent remaining compiler bugs:
* We're not getting partial ordering between NSCoder's
encode(AnyObject, forKey: String) and NSKeyedArchiver's version of
that method, and
* Dynamic lookup (into AnyObject) doesn't know how to find the new
names. We need the Swift name lookup tables enabled to address this.
Like decodeTopLevelObjectOfClass(_:forKey:), this API works very nicely
as a generic method in Swift, and this one is actually the one we expect
to be commonly used. One thing to note here is that these methods are
stricter than their ObjC counterparts: they will do a forced checked cast
even when the unarchiver does not use "secure" coding.
This depends on the previous commit; without it, we do not actually
enforce type safety for these methods.
The API notes change is to make the non-generic version of this method
unavailable so that it does not participate in overload resolution.
Without this we prefer the non-generic method unless there's a contextual
type for the result. I've filed rdar://problem/22243198 to track taking
this out once Foundation has updated their headers.
rdar://problem/17060110 (again)
Swift SVN r31154
Due to the fact that AnyClass is not Hashable, and that currently
NSKeyedArchiver/Unarchiver work with NSObject-derived, NSCoding
compliant classes, we are marking the decodeObjectOfClasses API refined
for Swift in our objc header and providing the desired overlay in our
overlay as shown below.
Arrays were also considered (for both API), but the underlying
implementation is entirely set-based, and using Arrays in Swift vs Sets
in objective C felt like too far a deviation.
Patch by Michael LeHew Jr.
Changes to the Dictionary test are caused by bumping the Fonudation API
epoch and taking in a fix in the types used in an NSDictionary
initializer.
rdar://21486551
Swift SVN r30297
The rule changes are as follows:
* All functions (introduced with the 'func' keyword) have argument
labels for arguments beyond the first, by default. Methods are no
longer special in this regard.
* The presence of a default argument no longer implies an argument
label.
The actual changes to the parser and printer are fairly simple; the
rest of the noise is updating the standard library, overlays, tests,
etc.
With the standard library, this change is intended to be API neutral:
I've added/removed #'s and _'s as appropriate to keep the user
interface the same. If we want to separately consider using argument
labels for more free functions now that the defaults in the language
have shifted, we can tackle that separately.
Fixes rdar://problem/17218256.
Swift SVN r27704
The contract for LazyResolver::loadAllMembers() was that the caller
would handle actually adding the members, since it was an iterable
declaration context and could centralize that (simple) logic. However,
this fails in the Clang importer in rare but amusing ways when some of
the deferred actions (e.g., finishing a protocol conformance) depend
on having the members already set. The deferred action occurs after
the member list is complete in ClangImporter's loadAllMembers(), but
before its caller actual set the member list, leaving incomplete
conformances. Fixes rdar://problem/18884272.
Swift SVN r25630
Require 'as' when converting from Objective-C type to native type (but
continue to allow implicit conversion from native to Objective-C). This
conversion constraint is called ExplicitConversion; all implicit
conversions are covered by the existing Conversion constraint. Update
standard library and tests to match.
Swift SVN r24496
Previously the "as" keyword could either represent coercion or or forced
downcasting. This change separates the two notions. "as" now only means
type conversion, while the new "as!" operator is used to perform forced
downcasting. If a program uses "as" where "as!" is called for, we emit a
diagnostic and fixit.
Internally, this change removes the UnresolvedCheckedCastExpr class, in
favor of directly instantiating CoerceExpr when parsing the "as"
operator, and ForcedCheckedCastExpr when parsing the "as!" operator.
Swift SVN r24253
Per API review with Ali. While we're here, give the initializer a corresponding 'rawValue' argument label, and change the associated type name to RawValue to match.
Swift SVN r21888
Redefine the RawRepresentable protocol to use an 'init?' method instead of 'fromRaw(Raw)', and a 'raw' get-only property instead of 'toRaw()'. Update the compiler to support deriving conformances for enums and option sets with the new protocol. rdar://problem/18216832
Swift SVN r21762
