Not the superclass's. This can cause mapping types out of context to not
resolve archetypes, because the DeclContexts won't match, e.g:
internal class _IteratorBox<Base: IteratorProtocol> :
_AnyIteratorBoxBase<Base.Element> { internal override func next() ->
Base.Element? }
Here, _IteratorBox's associated type Element for IteratorProtocol is
Base.Element, but the conformance comes from the superclass,
_AnyIteratorBoxBase. This meant that Base.Element couldn't be mapped to
an interface type, which should be:
(dependent-member
(generic-type-parameter depth=0 index=0) member=Element)
It appears we were only using this to see if an associated type was
derived or defaulted. This code didn't mesh well with the other stuff
I was doing for default implementations, so I'd rather rip it out and
just rely on calling 'isImplicit' to check for derived associated
types instead.
Note that there's a small change of behavior -- if an associated type
is derived for one conformance, and then used as a witness in another,
we were previously only marking it as defaulted in the first one,
but now it is marked as defaulted in both. I do not believe this has
any meaningful consequences.
Migrate the check for whether a given type is representable in
Objective-C, which is currently used to verify when @objc can be
inferred or verify that an explicitly-written @objc is well-formed,
from Sema into a set of queries on the Type within the AST library, so
it can be used in other parts of the compiler.
As part of this refactoring, clean up and improve a number of aspects
of this code:
* Unify the "trivially representable" and "representable" code paths
into a single code path that covers these cases. Clarify the
different levels of "representable" we have in both the code and
in comments.
* Distinguish between representation in C vs. representation in
Objective-C. While we aren't using this now, I'm anticipating it
being useful to allow exporting C interfaces via @_cdecl (or
similar).
* Eliminate the special cases for bridging String/Array/Dictionary/Set
with their Foundation counterparts; we now consult
_ObjectiveCBridgeable conformances exclusively to get this
information.
* Cache foreign-representation information on the ASTContext in a
manner that will let us more easily get the right answer across
different contexts while providing more sharing than the TypeChecker
version.
Annoyingly, this only seemed to fix a small class of error where we
were permitting Unsafe(Mutable)Pointer<T> to be representable in
Objective-C when T was representable but not trivially representable,
e.g., T=String or T=AnyObject.Type.
When performing Swift API dumps, it's helpful to avoid putting
redundant APIs into the results. Therefore, filter out any APIs that
are overrides of another API or are witnesses for a protocol
requirement, since the original definition (that doesn't override any
other or is a protocol requirement) is what determines the APIs name.
Fix some interface type/context type confusion in the AST synthesis from the previous patch, add a unique private mangling for behavior protocol conformances, and set up SILGen to emit the conformances when property declarations with behaviors are visited. Disable synthesis of the struct memberwise initializer if any instance properties use behaviors; codegen will need to be redesigned here.
Parse 'var [behavior] x: T', and when we see it, try to instantiate the property's
implementation in terms of the given behavior. To start out, behaviors are modeled
as protocols. If the protocol follows this pattern:
```
protocol behavior {
associatedtype Value
}
extension behavior {
var value: Value { ... }
}
```
then the property is instantiated by forming a conformance to `behavior` where
`Self` is bound to the enclosing type and `Value` is bound to the property's
declared type, and invoking the accessors of the `value` implementation:
```
struct Foo {
var [behavior] foo: Int
}
/* behaves like */
extension Foo: private behavior {
@implements(behavior.Value)
private typealias `[behavior].Value` = Int
var foo: Int {
get { return value }
set { value = newValue }
}
}
```
If the protocol requires a `storage` member, and provides an `initStorage` method
to provide an initial value to the storage:
```
protocol storageBehavior {
associatedtype Value
var storage: Something<Value> { ... }
}
extension storageBehavior {
var value: Value { ... }
static func initStorage() -> Something<Value> { ... }
}
```
then a stored property of the appropriate type is instantiated to witness the
requirement, using `initStorage` to initialize:
```
struct Foo {
var [storageBehavior] foo: Int
}
/* behaves like */
extension Foo: private storageBehavior {
@implements(storageBehavior.Value)
private typealias `[storageBehavior].Value` = Int
@implements(storageBehavior.storage)
private var `[storageBehavior].storage`: Something<Int> = initStorage()
var foo: Int {
get { return value }
set { value = newValue }
}
}
```
In either case, the `value` and `storage` properties should support any combination
of get-only/settable and mutating/nonmutating modifiers. The instantiated property
follows the settability and mutating-ness of the `value` implementation. The
protocol can also impose requirements on the `Self` and `Value` types.
Bells and whistles such as initializer expressions, accessors,
out-of-line initialization, etc. are not implemented. Additionally, behaviors
that instantiate storage are currently only supported on instance properties.
This also hasn't been tested past sema yet; SIL and IRGen will likely expose
additional issues.
TypeAlignments.h predates this whole mess; it was used for types with
stronger alignment in PointerLikeTypeTraits than the old default of
"2 by fiat and assumption". All remaining forward-declared types are
AST types, so fold them into TypeAlignments.h.
(The one exception is SILTypeList.h, but that's already gone on master.)
To avoid future ODR issues, explicitly include TypeAlignments.h into
every header that defines a type it forward-declares.
I wish we could use partial specialization to provide PointerLikeTypeTraits
for all derived classes of Decl, TypeBase, etc, but that's not something
you can do in C++ if you don't control the traits class.
This eliminates some minor overheads, but mostly it eliminates
a lot of conceptual complexity due to the overhead basically
appearing outside of its context.
The main idea here is that we really, really want to be
able to recover the protocol requirement of a conformance
reference even if it's abstract due to the conforming type
being abstract (e.g. an archetype). I've made the conversion
from ProtocolConformance* explicit to discourage casual
contamination of the Ref with a null value.
As part of this change, always make conformance arrays in
Substitutions fully parallel to the requirements, as opposed
to occasionally being empty when the conformances are abstract.
As another part of this, I've tried to proactively fix
prospective bugs with partially-concrete conformances, which I
believe can happen with concretely-bound archetypes.
In addition to just giving us stronger invariants, this is
progress towards the removal of the archetype from Substitution.
A protocol conformance needs to know what declarations satisfy requirements;
these are called "witnesses". For a value (non-type) witness, this takes the
form of a ConcreteDeclRef, i.e. a ValueDecl plus any generic specialization.
(Think Array<Int> rather than Array<T>, but for a function.)
This information is necessary to compile the conformance, but it causes
problems when the conformance is used from other modules. In particular,
the type used in a specialization might itself be a generic type in the
form of an ArchetypeType. ArchetypeTypes can't be meaningfully used
outside their original context, however, so this is a weird thing to
have to deal with. (I'm not going to go into when a generic parameter is
represented by an ArchetypeType vs. a GenericTypeParamType, partially
because I don't think I can explain it well myself.)
The above issue becomes a problem when we go to use the conformance from
another module. If module C uses a conformance from module B that has a
generic witness from module A, it'll think that the archetypes in the
specialization for the witness belong in module B. Which is just wrong.
It turns out, however, that no code is using the full specializations for
witnesses except for when the conformance is being compiled and emitted.
So this commit sidesteps the problem by just not serializing the
specializations that go with the ConcreteDeclRef for a value witness.
This doesn't fix the underlying issue, so we should probably still see
if we can either get archetypes from other contexts out of value witness
ConcreteDeclRefs, or come up with reasonable rules for when they're okay
to use.
rdar://problem/23892955
Apart from being general compile-time goodness, this helps break a
circularity issue involving serialization cross-references and the
Clang importer.
The test is being added to validation-tests because it relies on
several levels of non-laziness in the compiler, all of which we'd
like to fix. It's making sure we don't regress here, but it isn't
actually verifying this change in particular.
rdar://problem/22364953
Swift SVN r31455
Specifically track when we're resolving type witnesses for a given
conformance, and refuse to recursively attempt to resolve those type
witnesses. The standard library patch in rdar://problem/21789238
triggers this, and isolating it in a small test case has proven
illusive.
Swift SVN r30160
Modules occupy a weird space in the AST now: they can be treated like
types (Swift.Int), which is captured by ModuleType. They can be
treated like values for disambiguation (Swift.print), which is
captured by ModuleExpr. And we jump through hoops in various places to
store "either a module or a decl".
Start cleaning this up by transforming Module into ModuleDecl, a
TypeDecl that's implicitly created to describe a module. Subsequent
changes will start folding away the special cases (ModuleExpr ->
DeclRefExpr, name lookup results stop having a separate Module case,
etc.).
Note that the Module -> ModuleDecl typedef is there to limit the
changes needed. Much of this patch is actually dealing with the fact
that Module used to have Ctx and Name public members that now need to
be accessed via getASTContext() and getName(), respectively.
Swift SVN r28284
Allows us to distinguish between "we know this conformance exists" and
"we're doing a detailed check of this conformance". Use it, rather
than membership in the nebulous ASTContext-wide caching structure
"ConformsTo", to detect recursive attempts to complete a conformance.
Swift SVN r26248
* Lift NormalProtocolConformance::hasTypeWitness() to
ProtocolConformance. This method can be used to determine whether a
potentially invalid conformance has a particular type witness.
* ProtocolConformance::getWitness() may return nullptr if the witness
does not exist.
* In TypeChecker::getWitnessType(), don't complain that a builtin
protocol is broken if it's the conformance that's broken.
* ConformanceChecker should only emit diagnostics from within calls to
checkConformance().
* TypeChecker::conformsToProtocol() now returns true if the type
has a declared conformance to the protocol, regardless of whether the
conformance is valid. Clients must check the validity of the
ProtocolConformance themselves if necessary.
<rdar://problem/19495341> Can't upcast to parent types of type constraints without forcing
Swift SVN r25326
... and stop doing it when we're separating the archetypes of
extensions from the types they extend. I wasn't able to isolate a
useful test case for this; it triggers when building the standard
library with extension archetypes separated.
Swift SVN r20814
Previously, we only retained the module in which a normal protocol
conformance occurred, which meant we either had to go searching for
the appropriate extension (yuck) or do without that information. This
is part of the separating-extension-archetypes work.
Swift SVN r20793
sane and ad ProtocolConformance::getSubstitutedGenericParams() for
returning the generic params that were substituted into by a specialized
protocol conformance.
I am going to use this to handle inherited specialized inherited
conformance devirtualization.
Swift SVN r16907
This fixes the following two bugs:
1. We sometimes would create new conformances when deserializing a
witness method which would not be mapped in the SILModule to the
appropriate witness table. This would cause us to be unable to perform
devirtualization of this witness method. This is tested via a new
verifier check.
2. Different conformances would be created for an instance of a base
protocol and the original protocol. This would cause IRGen to try to
emit witness table global variables with differing types, hitting an
assertion. This is tested via a traditional test.
Swift SVN r15362
After chatting with Doug about this issue, the conclusion was reached that it is
more important to have the pointer identity of a protocol conformance be the
same for all types that reduce to the same canonical type.
Swift SVN r15335
Pass in the context generic parameters that correspond to the substitution vector in Substitution::subst. When we build the type substitution map, also collect the conformances from the substitutions into a map we can use to fill in those conformances in substituted substitutions where necessary, without relying on the '.Archetype' field.
Swift SVN r14964
A protocol conformance of a class A to a protocol P can be inherited
by a subclass B of A unless
- A requirement of P refers to Self (not an associated type thereof)
in its signature,
+ *except* when Self is the result type of the method in P and the
corresponding witness for A's conformance to B is a DynamicSelf
method.
Remove the uses of DynamicSelf from the literal protocols, going back
to Self. The fact that the conformances of NSDictionary, NSArray,
NSString, etc. to the corresponding literal protocols use witnesses
that return DynamicSelf makes NSMutableDictionary, NSMutableArray,
NSMutableString, and other subclasses still conform to the
protocol. We also correctly reject attempts to (for example) create an
NSDecimalNumber from a numeric literal, because NSNumber doesn't
provide a suitable factory method by which any subclass can be literal
convertible.
Swift SVN r14204
Change GenericFunctionType to reference a GenericSignature instead of containing its generic parameters and requirements in-line, and clean up some interface type APIs that awkwardly returned ArrayRef pairs to instead return GenericSignatures instead.
Swift SVN r13807
When applying getInheritedConformance to a specialized conformance, reapply the specialization to the found inherited conformance so we get a conformance for the same type we put in, making the specializer's job easier when finding conformances to insert into archetype_methods. To expose the problems this fixes, add a check in the SIL verifier that ArchetypeMethodInsts carry a ProtocolConformance that actually matches their lookup type.
Swift SVN r12988
Substitute a...um...substitution by remapping its Replacement mapping and recursively remapping any ProtocolConformances it has. Modify the Specializer to use Substitution::subst when specializing the substitutions of ArchetypeMethod and Apply instructions.
Swift SVN r12900
This is infrastructure toward allowing us to construct conformances
where there are type variables <rdar://problem/15168483>, which keeps
tripping up library work.
Swift SVN r12899
1. Implement parser and sema support for our subscript syntax proposal in
protocols. Now you have to use subscript(..) { get } or {get set} to
indicate what you want. I suspect that the syntax will evolve, but at
least we can express what we need now.
2. Change the representation of SubscriptDecls in protocols to make
(empty) funcdecls for the getter and setter. This guarantees that
every subscript has at least a getter.
Swift SVN r12555
