Inference of type witnesses for associated types was previously
implemented as part of value witness matching in the constraint
solver. This led to a number of serious problems, including:
- Recursion problems with the solver hunting for a type witness,
which triggers more attemts to match value witnesses...
- Arbitrarily crummy attempts to break the recursion causing
type-check failures in fun places.
- Ordering dependencies abound: different results depending on which
value witnesses were satisfied first, failures because of the order
in which we attempted to infer type witnesses, etc.
This new implementation of type witness inference uses a separate pass
that occurs whenever we're looking for any type witness, and solves
all of the type witnesses within a given conformance
simultaneously. We still look at potential value witnesses to infer
type witnesses, but we match them structurally, without invoking the
constraint solver.
There are a few caveats to this implementation:
* We're not currently able to infer type witnesses from value
witnesses that are global operators, so some tricks involving global
operators (*cough* ~> *cough*) might require some manually-specified
type witnesses. Note that the standard library doesn't include any
such cases.
* Yes, it's another kind of solver. At simple one, fortunately.
On the other hand, this implementation should be a big step forward:
* It's far more predictable, order-invariant, and non-recursive.
* The diagnostics for failures to infer type witnesses have
improved.
Fixes rdar://problem/20598513.
Swift SVN r27616
This reverts commit r27576.
(In some cases of catastrophic error recovery, ctor types may still be null during constraint solving, so it was wrong of me to assume otherwise.)
Swift SVN r27599
We need to use the constrants from the extension, otherwise we might
pass in the wrong witness method table at the call site, among other
problems.
Fixes rdar://problem/20532214.
Swift SVN r27585
This reverts commit r27568 to unblock the buildbot. It regressed three
compiler crashers:
Swift :: compiler_crashers_fixed/0367-llvm-errs.swift
Swift :: compiler_crashers_fixed/1769-getselftypeforcontainer.swift
Swift :: compiler_crashers_fixed/1916-swift-nominaltypedecl-getdeclaredtypeincontext.swift
Swift SVN r27576
- When inferring 'throws' for a closure function type, look inside of catchless do blocks for 'try' expressions.
- When simplifying overload constriants for applications of throwing initializers, the bound member type of the initializer should also be marked as throwing.
(Not doing so would cause us to incorrectly reject the overload.)
Swift SVN r27568
Fix crashes when type-checking ErrorType dynamic casts when NSError isn't available. Split the ErrorType execution tests into separate units for bridging and non-bridging, so that we get better coverage of this situation in both ObjC and non-ObjC builds. Fixes rdar://problem/20585210.
Swift SVN r27556
Update the Fix-It thats suggests adding a #available() check to include the
wildcard query '*', which is now required. We were omitting it before, which
meant that after applying this Fix-It the developer would get a second Fix-It
to add the '*'.
rdar://problem/20601569
Swift SVN r27514
The type checker (and various other parts of the front end) jump
through many hoops to try to cope with the lack of a proper
declaration for an inferred type witness, causing various annoying
bugs. Additionally, we were creating implicit declarations for
derived/synthesized witnesses, leading to inconsistent AST
representations. This ch
Note that we'll now end up printing the inferred type aliases for type
witnesses, which represents a reversal of the decision that closed
rdar://problem/15168378. This result is more consistent.
Now with a simpler accessibility computation.
Swift SVN r27512
Handle substitutions properly when a typealias declared in a protocol
extension is used to satisfy an associated type requirement. Fixes
rdar://problem/20564605.
Swift SVN r27490
The type checker (and various other parts of the front end) jump
through many hoops to try to cope with the lack of a proper
declaration for an inferred type witness, causing various annoying
bugs. Additionally, we were creating implicit declarations for
derived/synthesized witnesses, leading to inconsistent AST
representations. This ch
Note that we'll now end up printing the inferred type aliases for type
witnesses, which represents a reversal of the decision that closed
rdar://problem/15168378. This result is more consistent.
Swift SVN r27487
Add syntax "[#Color(...)#]" for object literals, to be used by
Playgrounds for inline color wells etc. The arguments are forwarded to
the relevant constructor (although we will probably change this soon,
since (colorLiteralRed:... blue:... green:... alpha) is kind of
verbose). Add _ColorLiteralConvertible and _ImageLiteralConvertible
protocols, and link them to the new expressions in the type checker.
CSApply replaces the object literal expressions with a call to the
appropriate protocol witness.
Swift SVN r27479
already. NFC right now, but this allows us to simplify SILGen.
It would also be reasonable to do this in the parser instead of sema, and would also
be reasonable to do for deinit and normal void-returning functions as well, thoughts
welcome.
Swift SVN r27468
When we're checking for a particular witness in a protocol conformance
because the result is needed elsewhere, capture the diagnostic we
would emit and then store it in the ASTContext. We will emit these
diagnostics when doing the full check of the conformance. Addresses
the rest of rdar://problem/20564378.
Swift SVN r27449
Suppress API availability diagnostics about protocol conformances when the
-disable-availability-checking frontend flag is passed. We weren't
checking the flag before, so there was no way to disable this diagnostic.
I've added a test to make sure this flag is honored. We can remove the test when
we remove the flag, which is temporary.
Swift SVN r27439
Fixes the crash in rdar://problem/20564378. In these cases, we end up
swallowing some diagnostics. That will be addressed in a subsequent
commit.
Swift SVN r27436
The post-type-checking error that was here is arguably better QoI, but it is causing ambiguities that break the non-ObjC-compatible build in the stdlib. We shouldn't even attempt these conversions if there's no runtime support to back them up.
Swift SVN r27407
This doesn't actually break the circular type-checking issues with
have with associated type inference, but it makes them less
painful. Fixes rdar://problem/20549165.
While here, and as a test, remove the _prext_underestimateCount
workound from the library. _CollectionDefaultsType now refines
_SequenceDefaultsType.
Swift SVN r27368
Allow an unversioned 'deprecated' attribute to specify unconditional
deprecation of an API, e.g.,
@availability(*, deprecated, message="sorry")
func foo() { }
Also support platform-specific deprecation, e.g.,
@availability(iOS, deprecated, message="don't use this on iOS")
func bar() { }
Addresses rdar://problem/20562871.
Swift SVN r27355
Move the map that keeps track of conforming decl -> requirement from ASTContext
to a nominal type's ConformanceLookupTable, and populate it lazily.
This allows getSatisfiedProtocolRequirements() to work with declarations from module files.
Test on the SourceKit side.
Part of rdar://20526240.
Swift SVN r27353
Allow an unversioned 'deprecated' attribute to specify unconditional
deprecation of an API, e.g.,
@availability(*, deprecated, message="sorry")
func foo() { }
Also support platform-specific deprecation, e.g.,
@availability(iOS, deprecated, message="don't use this on iOS")
func bar() { }
Addresses rdar://problem/20562871.
Swift SVN r27339
This is an internal-only affordance for the numerics team to be able to work on SIMD-compatible types. For now, it can only increase alignment of fixed-layout structs and enums; dynamic layout, classes, and other obvious extensions are left to another day when we can design a proper layout control design.
Swift SVN r27323
Introduce basic validation for throwing @objc initializers, e.g., a
failable @objc initializer cannot also be throwing. However,
Objective-C selector computation is broken.
Swift SVN r27292
For a throwing @objc method, we place the error parameter just before
the last parameter of (possibly-optional) function type. Allow this
default to be overridden with an explicit @objc(selector) attribute,
which can contain an "error" selector piece to indicate where the
error parameter goes (or an "Error" word suffix on the first selector
piece to put the error argument at the beginning).
Swift SVN r27278
