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
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
DiscardAssignment expressions are special in that during constraint generation they'll introduce a new type variable, but not place any constraints upon it. (They are the only expression kind that behaves in this way.) If no subsequent expressions constrain the type variable, we may end up with a failed constraint system that's devoid of constraints, and hence no information to synthesize a diagnostic from. With no diagnostic associated with the DiscardAssignmentExpr's source location, we'll attempt to generate SIL and raise an assertion failure. Fortunately, we can detect these cases during the constraint salvage phase, and raise an appropriate error.
Swift SVN r19020
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
Do this by only warning on self-referential uses of a variable when there's
not another binding found in the local scope. This probably still restricts
some reasonable edge cases, but it at least allows shadowing the variable
with a local name.
<rdar://problem/17087232>
Swift SVN r18771
One difficulty in generating reasonable diagnostic data for type check failures has been the fact that many constraints had been synthesized without regard for where they were rooted in the program source. The result of this was that even though we would store failure information for specific constraints, we wouldn't emit it for lack of a source location. By making location data a non-optional component of constraints, we can begin diagnosing type check errors closer to their point of failure.
Swift SVN r18751
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
- rdar://problem/16776273, wherein conversions between nil and .None were permitted
due to an implicit conversion between nil and COpaquePointer.
- rdar://problem/16877526, where we needed to add new equality overloads to handle
conversions between nil and .None given the supression of user conversions.
(Some minor tweaks this time around for better interoperability with AnyObject.)
Swift SVN r18498
- rdar://problem/16776273, wherein conversions between nil and .None were permitted
due to an implicit conversion between nil and COpaquePointer.
- rdar://problem/16877526, where we needed to add new equality overloads to handle
conversions between nil and .None given the supression of user conversions.
(Thanks to Ted for the overloads and test.)
Swift SVN r18473
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
We can't actually make the "is" check any more efficient for arrays
anyway, and re-using the checked casting code makes "is" work properly
for arrays. More of <rdar://problem/16952771>.
Swift SVN r18395
The "is" expression itself isn't really able to cope with optionals
well itself, so in the hard cases we'll defer to a conditional checked
cast and then check whether the resulting optional is non-empty. Fixes
the rest of <rdar://problem/16953860>.
Swift SVN r18361
assert() and fatalError()
These functions are meant to be used in user code. They are enabled in debug
mode and disabled in release or fast mode.
_precondition() and _preconditionFailure()
These functions are meant to be used in library code to check preconditions at
the api boundry. They are enabled in debug mode (with a verbose message) and
release mode (trap). In fast mode they are disabled.
_debugPrecondition() and _debugPreconditionFailure()
These functions are meant to be used in library code to check preconditions that
are not neccesarily comprehensive for safety (UnsafePointer can be null or an
invalid pointer but we can't check both). They are enabled only in debug mode.
_sanityCheck() and _fatalError()
These are meant to be used for internal consistency checks. They are only
enabled when the library is build with -DSWIFT_STDLIB_INTERNAL_CHECKS=ON.
I modified the code in the standard library to the best of my judgement.
rdar://16477198
Swift SVN r18212
I suspect this can be made much better. It only
works for comparing Array<T> and Array<T>,
NativeArray<T> and NativeArray<T>, etc., not
NativeArray<T> and Array<T>. I also suspect
the implementation can be made better. The goal
was to make this functional, as this basic
functionality was missing.
Implements <rdar://problem/16768095>.
Swift SVN r18150
I didn't want to rip this logic out wholesale. There is a possibility
the character lexing can be reborn/revisited later, and
disabling it in the parser was easy.
Swift SVN r18102
