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
This consolidates the \x, \u, and \U escape sequences into one \u{abc} escape sequence.
For now we still parse and cleanly reject the old forms with a nice error message, this
will eventually be removed in a later beta (tracked by rdar://17527814)
Swift SVN r19435
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
This allows us to cast "through" a bridged class type in an "as" case,
e.g.,
if let str = obj as String { ... }
where obj is an AnyObject (or optional/implicitly unwrapped optional
thereof). In such cases, we perform a checked cast to the
corresponding class type (NSString in this case) and then convert the
(optional!) result down to the value type.
Addresses the main part of <rdar://problem/15288553>, but we still
have trouble with "is" with optionals, and the #if false'd out
testcase incorrectly fails due to <rdar://problem/16953860>.
Swift SVN r18347
This allows "obj.description!" to work on iOS when 'obj' is an AnyObject,
even though 'description' is an implicit property created by the importer.
Swift SVN r18149
This fixes a case where the Swift-variadic and C-varargs versions of
various initializers were superseding each other
<rdar://problem/16801456>.
It also uncovered some more cases where we weren't getting quite the
right semantics for factory-methods-as-initializers, which are also
fixed here.
Swift SVN r18010
Test that string bridging interacts successfully both with native ObjC NSString methods and with Swift subclasses that define String methods end-to-end.
Swift SVN r5367
