Currently they do nothing but allow stdlib code to use regular (Bool)
types. However, soon the wrappers for the _native variants will
provide point-of-use sanity checking.
These need to be fully generic to support class protocols and
single-payload enums (not just for optional). It also avoids a massive
amount of overloading for all the reference type variations
(AnyObject, Native, Unknown, Bridge) x 2 for optional versions of
each.
Because the wrapper is generic, type checking had to be deferred until
IRGen. Generating code for the wrapper itself will result in an
IRGen-time type error. They need to be transparent anyway for proper
diagnostics, but also must be internal.
Note that the similar external API type checks ok because it
forces conformance to AnyObject.
The sanity checks are disabled because our current facilities for
unsafe type casting are incomplete and unsound. SILCombine can
remove UnsafeMutablePointer and RawPointer casts by assuming layout
compatibility. IRGen will later discover layout incompatibility and
generate a trap.
I'll send out a proposal for improving the casting situation so we can
get the sanity checks back.
Swift SVN r28057
includes a number of QoI things to help people write the correct code. I will commit
the testcase for it as the next patch.
The bulk of this patch is moving the stdlib, testsuite and validation testsuite to
the new syntax. I moved a few uses of "as" patterns back to as? expressions in the
stdlib as well.
Swift SVN r27959
This reverts commit 64e9f11211a19fa603f5bc2d2bea171a9b07d3fa.
I think this is breaking ExistentialCollection test in the
Release + stdlib asserts build.
Swift SVN r27947
The wrappers for the _native variants provide point-of-use sanity checking.
They also allows stdlib code to use regular (Bool) types.
These need to be fully generic to support class protocols. It also
avoids a massive amount of overloading for all the reference type
variations (AnyObject, Native, Unknown, Bridge) x 2 for optional
versions of each.
Because the wrapper is generic, type checking had to be deferred until
IRGen. Generating code for the wrapper itself will result in an
IRGen-time type error. They need to be transparent anyway for proper
diagnostics, but also must be internal.
The external API passes type checks because it forces conformance to AnyObject.
Swift SVN r27930
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
This changes 'if let' conditions to take general refutable patterns, instead of
taking a irrefutable pattern and implicitly matching against an optional.
Where before you might have written:
if let x = foo() {
you now need to write:
if let x? = foo() {
The upshot of this is that you can write anything in an 'if let' that you can
write in a 'case let' in a switch statement, which is pretty general.
To aid with migration, this special cases certain really common patterns like
the above (and any other irrefutable cases, like "if let (a,b) = foo()", and
tells you where to insert the ?. It also special cases type annotations like
"if let x : AnyObject = " since they are no longer allowed.
For transitional purposes, I have intentionally downgraded the most common
diagnostic into a warning instead of an error. This means that you'll get:
t.swift:26:10: warning: condition requires a refutable pattern match; did you mean to match an optional?
if let a = f() {
^
?
I think this is important to stage in, because this is a pretty significant
source breaking change and not everyone internally may want to deal with it
at the same time. I filed 20166013 to remember to upgrade this to an error.
In addition to being a nice user feature, this is a nice cleanup of the guts
of the compiler, since it eliminates the "isConditional()" bit from
PatternBindingDecl, along with the special case logic in the compiler to handle
it (which variously added and removed Optional around these things).
Swift SVN r26150
The standard library has grown significantly, and we need a new
directory structure that clearly reflects the role of the APIs, and
allows future growth.
See stdlib/{public,internal,private}/README.txt for more information.
Swift SVN r25876
