It looks like the code for generating optional-to-optional conversions may still have problems with nested optional subtype conversions, but I don't think the application phase is the right place to address them. To holistically address this class of problem, we may want to reconsider how these kinds of optional conversions are threaded through the constraint solver post-1.0.
Swift SVN r19731
Introduce the new BooleanLiteralConvertible protocol for Boolean
literals. Take "true" and "false" as real keywords (which is most of the
reason for the testsuite churn). Make Bool BooleanLiteralConvertible
and the default Boolean literal type, and ObjCBool
BooleanLiteralConvertible. Fixes <rdar://problem/17405310> and the
recent regression that made ObjCBool not work with true/false.
Swift SVN r19728
Previously, bridged value types and their corresponding Objective-C
classes allow inter-conversion via a number of user-defined conversion
functions in the Foundation module. Instead, make this a general
feature of the type checker so we can reason about it more
directly. Fixes <rdar://problem/16956098> and
<rdar://problem/17134986>, and eliminates 11 (half) of the
__conversion functions from the standard library and overlays.
A few notes:
- The XCTest changes are because a String can no longer directly
conform to CVarArg: this is a Good Thing (TM), because it should be
ambiguous: did you mean to pass it as an NSString or a C string?
- The Objective-C representations for the bridged collections are
hard-coded in the type checker. This is unfortunate and can be
remedied by adding another associated type to the
_BridgedToObjectiveC protocol.
Swift SVN r19618
If the lookup was resolved by optional unwrapping, unwrap the metatype when we apply the solution so we don't try to create an invalid metatype conversion from T?.Type to T.Type. Fixes <rdar://problem/17542185>.
Swift SVN r19500
When we see a '.member' expression in optional context, look for the member in the optional's object type if it isn't found in Optional itself. <rdar://problem/16125392>
Swift SVN r19469
Allow a String value to be implicitly converted to ConstUnsafePointer<{UInt8,Int8,Void}> by string-to-pointer conversion, when enabled by a staging flag.
Swift SVN r19366
JoeP helped tweak things to ensure that pointer conversions are still
considered, but we no longer need the disjunction on InOutExprs to accommodate
user-defined inout conversions.
This causes some regressions in error reporting:
<rdar://problem/17489983> inout type mismatches complain about '@lvalue inout T'
<rdar://problem/17489894> inout not rejected as operand to assignment operator
Swift SVN r19306
We no longer need this language feature. The Sema support is still skeletally kept in place because removing it seems to totally break pointer conversions; I need to work with Joe and Doug to figure out why that's the case.
Swift SVN r19289
We haven't been advertising this syntax much, and it's closure form
was completely broken anyway, so don't jump through hoops to provide
great Fix-Its here.
Swift SVN r19277
Previously, we were unable to handle bridged downcasts to optional
types from optional sources, because because we applied the bridging
operation after we had already evaluated all of the bound optionals
(causing a crash). Now, we perform the bridging immediately after the
underlying forced or conditional cast, before evaluating the outer
bound optionals.
This also eliminates a bunch of code duplication between the forced
and conditional downcasts, now that the bridging code is shared.
Swift SVN r19065
Previously, a forced downcast was implemented as a conditional
downcast following by an implicit unwrap, and relied on peephole
optimizations (in both constraint application and SILGen) to turn them
into a forced downcast. However, these didn't kick in for AnyObject ->
T[] downcasts, bypassing the more-efficient deferred checking our
native collections can do. Finishes <rdar://problem/17319154>.
Swift SVN r19064
Now that we use bridgeFromObjectiveCConditional to perform conditional
bridging, make bridgeFromObjectiveC handle forced bridging. For the
latter, deferred checking is acceptable.
Almost all of <rdar://problem/17319154>.
Swift SVN r19046
These changes prevent a certain class of bogus errors, as well as several crashers. Unfortunately, though, they don't quite get us to the point where we can broadly use recursively defined protocol requirements, in the standard library. (To do so would require significant changes across the entire stack.)
Swift SVN r19019
Add primitive type-checker rules for pointer arguments. An UnsafePointer argument accepts:
- an UnsafePointer value of matching element type, or of any type if the argument is UnsafePointer<Void>,
- an inout parameter of matching element type, or of any type if the argument is UnsafePointer<Void>, or
- an inout Array parameter of matching element type, or of any type if the argument is UnsafePointer<Void>.
A ConstUnsafePointer argument accepts:
- an UnsafePointer, ConstUnsafePointer, or AutoreleasingUnsafePointer value of matching element type, or of any type if the argument is ConstUnsafePointer<Void>,
- an inout parameter of matching element type, or of any type if the argument is ConstUnsafePointer<Void>, or
- an inout or non-inout Array parameter of matching element type, or of any type if the argument is ConstUnsafePointer<Void>.
An AutoreleasingUnsafePointer argument accepts:
- an AutoreleasingUnsafePointer value of matching element type, or
- an inout parameter of matching element type.
This disrupts some error messages in unrelated tests, which is tracked by <rdar://problem/17380520>.
Swift SVN r19008
This entry point is used in conditional downcasts (as?) to attempt to
bridge from an Objective-C class down to a specific native type (e.g.,
array, dictionary), bridging all elements eagerly so that it can
produce nil if the bridging would fail.
This is the scaffolding for <rdar://problem/17319154>, and makes the
example there work, but there is much more cleanup and optimization to
do.
Swift SVN r18999
This means that we'll get deferred checking of array and dictionary
downcasts when writing "arr as Derived[]",
"(dict as? Dictionary<DerivedKey, DerivedValue>)!", etc, when the
collection can do so.
This is both a general optimization and also staging for
<rdar://problem/17319154>.
Swift SVN r18975
This makes categories of NSString, NSArray, and NSDictionary available
on String, Array, and Dictionary. Note that we only consider
categories not present in the Objective-C Foundation module, because
we want to manually map those APIs ourselves. Hence, no changes to the
NSStringAPI. Implements <rdar://problem/13653329>.
Swift SVN r18920
This is all goodness, and eliminates a major source of implicit conversions.
One thing this regresses on though, is that we now reject "x == nil" where
x is an option type and the element of the optional is not Equtatable. If
this is important, there are ways to enable this, but directly testing it as
a logic value is more straight-forward.
This does not include support for pattern matching against nil, that will be
a follow on patch.
Swift SVN r18918
Semantically, these expressions handle the same thing: an upcast of a
collection when the underlying element types of the source are
subtypes of or can be bridged to subtypes of the destination. This
reduces some branching in the type checker and eliminates duplication
in SILGen.
Swift SVN r18865
Allow class metatypes (including class-constrained existential metatypes) to be treated as subtypes of AnyObject, and single-@objc protocol metatypes to be treated as subtypes of the Protocol class from objc. No codegen support yet, so this is hidden behind a frontend flag for now.
Swift SVN r18810
Tweak the AST representation and type-checking of default arguments to preserve a full ConcreteDeclRef with substitutions to the owner of the default arguments. In SILGen, emit default argument generators with the same genericity as the original function.
Swift SVN r18760
We removed this feature when we changed casting syntax, but left it in
the type checker to help migrate code via a Fix-It. We no longer need
it.
Swift SVN r18729
Previously, we were only changing whether the object was of the right
type, and not performing a deep check that (for example) the
underlying array contained NSStrings for an "is String[]". Fixes the
rest of <rdar://problem/16972956>.
Swift SVN r18728
Rather than only allowing downcasting from AnyObject, allow it for any
class or Objective-C existential type, e.g., "NSArray() as
Int[]". While here, reduce our reliance on implicit conversions when
checking bridging. This is most of <rdar://problem/16972956>, but 'is'
still doesn't work properly in these cases.
Swift SVN r18693
There's a bit of a reshuffle of the ExplicitCastExpr subclasses:
- The existing ConditionalCheckedCastExpr expression node now represents
"as?".
- A new ForcedCheckedCastExpr node represents "as" when it is a
downcast.
- CoerceExpr represents "as" when it is a coercion.
- A new UnresolvedCheckedCastExpr node describes "as" before it has
been type-checked down to ForcedCheckedCastExpr or CoerceExpr. This
wasn't a strictly necessary change, but it helps us detangle what's
going on.
There are a few new diagnostics to help users avoid getting bitten by
as/as? mistakes:
- Custom errors when a forced downcast (as) is used as the operand
of postfix '!' or '?', with Fix-Its to remove the '!' or make the
downcast conditional (with as?), respectively.
- A warning when a forced downcast is injected into an optional,
with a suggestion to use a conditional downcast.
- A new error when the postfix '!' is used for a contextual
downcast, with a Fix-It to replace it with "as T" with the
contextual type T.
Lots of test updates, none of which felt like regressions. The new
tests are in test/expr/cast/optionals.swift.
Addresses <rdar://problem/17000058>
Swift SVN r18556
Previously, we were relying on user-defined conversions to perform the
final bridging from the Objective-C class type (e.g., NSString) to its
Swift value type (String). That works for NSString <-> String, but not
for arbitrary arrays. Use the bridgeFromObjectiveC() witness instead,
so we can handle:
let obj: AnyObject = ...
let strArr: String[] = obj!
Fixes <rdar://problem/16952771>.
Swift SVN r18422
This allows us to cast an AnyObject (or optional thereof) down to a
specific array, e.g.,
if let strArr = obj as String[] { ... }
Addresses most of <rdar://problem/16952771>.
Swift SVN r18397
