Ensure we correctly handle the case where you're overriding a witness
that should be `public`. Currently this is working as a side-effect
of conformance checking, but we ought to be able to compute it with
lazy type-checking. No test case since it will be covered once we
rip out the eager type-checking in a following commit.
Modify relevant portions of the type-checker and parser to allow, when the 'LiteralExpressions' experimental feature is enabled, for arbitrary integer-typed expressions in enum raw value specifiers. These expressions will be type-checked and constant-folded into an integer literal expression, keeping the current interface of 'EnumElementDecl' consistent for clients.
Previously, 'EnumRawValuesRequest' had two different "modes" which were discerned based on typechecking stage (structural | interface), where the former had the request compute all raw values, both user-specified literal expressions and computing increment-derived values as well; the latter would also type-check the user-specified expressions and compute their types.
- With the need to have enum case raw values support arbitrary integer expressions, the request ('EnumRawValuesRequest') has been refactored and simplified to *always* both compute all case raw values and perform type-checking of user-specified raw value expressions. This is done in order to allow the AST-based constant-folding infrastructure ('ConstantFoldExpression' request) to run on the expressions. Constant folding is invoked during the evaluation of 'EnumRawValuesRequest' on all user-specified raw value expressions, in order to be able to compute subsequent increment values and ensure the expressions are foldable. If they are not, i.e. if constant folding fails, a relevant diagnostic will be emitted.
- 'EnumElementDecl' continues to store the raw value expression, which is no longer a 'LiteralExpr' but rather an 'Expr'; however, the getter ('getRawValueExpr') continues to return a 'LiteralExpr' by invoking the constant-folding request on the stored value, which is guaranteed to return a cached result from a prior invocation in 'EnumRawValuesRequest', assuming it succeeded.
- Furthermore, the 'structural' request kind was previously not cached, whereas now because the request must always do the complete type-checking work, it is always cached.
Resolves rdar://168005520
This change adds an experimental feature 'LiteralExpressions` which allows for use of simple binary expressions of integer type composed of literal value operands.
For now, such literal expressions are only supported in initializers of '@section` values.
Enable the feature by default, and add an experimental feature
`DeprecateCompatMemberwiseInit` to control the deprecation behavior
which was deferred from the proposal.
This change forces you to write ``@reparented` relationships
on an extension of a protocol, rather than on the protocol
itself.
The ProtocolConformance needs to be associated with some
GenericContext and IRGen expects it to be an ExtensionDecl.
That environment defines under what conditions the conformance
exists. We also need to define witnesses for the new parent's
requirements in an extension anyway, so it's a natural fit.
The previous workaround for this was kind of awful, as it'd
require searching all the protocol's extensions and "guess"
which extension they want to represent the conformance. While
we could try to synthesize an extension, there's two
challenges there:
1. Due to SuppressedAssociatedTypes, it's not so simple to
synthesize an unconstrained ExtensionDecl.
2. We currently rely on same-type requirements to pin the
associated types to particular witnesses of those requirements
in the extension. So it's not purely unconstrained! For example,
```
extension Seq: @reparented BorrowSeq where Iter == MyIter {}
```
The constraints that are disallowed (but not yet diagnosed)
are conditional conformance requirements, as the default
conformance for a reparenting cannot depend on those.
Thus, it's better that programmers to specify the extension.
A protocol that's been reparented declares it
by writing `@reparented` in its inheirtance clause
for each new parent. You can introduce a `@reparented`
parent to a pre-existing ABI-stable protocol's
inheritance hierarchy.
Only protocols declared to be `@reparentable` can be
used to reparent other protocols. Adding or removing
the `@reparentable` attribute is ABI-breaking, as it
effects the type metadata layout. Thus, reparentable
protocols must be born as such to use them with
protocols that are already ABI-stable.
This set of changes does not include the actual
implementation of ABI-stable reparenting.
For now, we write `read`/`modify` to .swiftinterface files
so they can be read by the draft implementation in current
compilers. Here are some of the issues:
* We _cannot_ support `read`/`modify` in Swift sources without
the user specifying a flag. That's because the idiom below occurs
in real code, and would be broken by such support. So when
we enable the `CoroutineAccessors` flag by default, we _must_
not support `read`/`modify` as accessor notations in source.
```
struct XYZ {
// `read` method that takes a closure
func read(_ closure: () -> ()) { ... }
// getter that uses the above closure
var foo: Type {
read { ... closure ... }
}
}
```
* .swiftinterface files don't have the above problem.
Accessor bodies aren't stored at all by default, and
when inlineable, we always write explicit `get`.
So we can continue to accept `read`/`modify` notation
in interface files.
So our strategy here is:
* We'll accept both `read`/`modify` and `yielding borrow`/`yielding mutate`
in interface files for a lengthy transition period.
* We'll write `read`/`modify` to swiftinterface files for
a little longer, then switch to `yielding borrow`/`yielding mutate`.
* We'll disable `read`/`modify` support in source files
when we enable `CoroutineAccessors` by default.
(We can't even diagnose, due to the above idiom.)
This means that early adopters will have to update their sources
to use the new terminology. However, swiftinterface files
will be exchangeable between the new and old compilers for a little
while.
We want to rely on the presence of yielding borrow with the introduction
of CoroutineAccessor feature. Emit it so that when the deployment target
is the same (or higher) as the CoroutineAccessor feature introduction we can
rely on the presence of yielding borrow. (assuming that the source code
was recompiled with a current toolchain at the time of introduction of the
feature)
Always enable checking for references to `@_implementationOnly` imports
even without library-evolution enabled but downgrade errors to warnings
by default. Clients should enable them as errors by adopting
`CheckImplementationOnly`.
This updates a large number of internal symbols, function names,
and types to match the final approved terminology. Matching the
surface language terminology and the compiler internals should
make the code easier for people to understand into the future.
This does not rename all the internal variables, functions, and types
whose names were based on the old syntax.
I think it adds new syntax support everywhere it's needed while
retaining enough of the old syntax support that early adopters will
see nice deprecation messages guiding them to the new syntax.
We now report properties referencing types imported from
implementation-only dependencies in non-library-evolution mode as the
memory layouts of structs and enums may be exposed to clients. Here we
exempt non-open classes from this check as clients hold pointers to
classes which hides the class internal memory layouts. Keep forbidding
it for open classes in order to error early, a client trying to subclass
an open class with such a reference from their property would already
see an error about members not deserializable.
Exclude properties with initial values from the memberwise initializer
if they are less accessible than the most accessible property, up to
`internal`. Introduce a compatibility overload that continues to
include the same properties as before until the next language mode.
This is gated behind the `ExcludePrivateFromMemberwiseInit` feature.
rdar://122416579
Store the original VarDecl in the same map we use for tracking the
original wrapper var for property wrappers. This will allow us to
use the same logic to determine the original var for both.
We need special handling for protocols whose requirement
signature exists but is in a serialized state, as we
cannot run the StructuralRequirementsRequest on such
a protocol as there's no work to be done, effectively.
This is similar to SuppressedAssociatedTypes, but infers
default requirements when primary associated types of
protocols are suppressed. This defaulting for the primary
associated types happens in extensions of the protocol,
along with generic parameters, whenever a source-written
requirement states a conformance requirement for the protocol.
Thus, the current scheme for this defaulting is a simplistic,
driven by source-written requirements, rather than facts
that are inferred while building generic signatures.
Defaults are not expanded for infinitely many associated types.
rdar://135168163
We need to serialize the underlying type substitution map for an
inlinable function. However, there is no reason to deserialize it
eagerly, since doing so can lead to cycles. It is better for
correctness and performance to only deserialize it when needed.
Technically this fixes a regression from #84299, but the actual
problem was there all along, it was just exposed by my change
on a specific project.
Fixes rdar://163301203.
Ensure that calls to SPI operators are only accepted in source files
importing the corresponding SPI group. This applies the same logic to
operators as we do for functions.
rdar://137713966
Implement the @export(implementation) and @export(interface) attributes
to replace @_alwaysEmitIntoClient and @_neverEmitIntoClient. Provide a
warning + Fix-It to start staging out the very-new
@_neverEmitIntoClient. We'll hold off on pushing folks toward
@_alwaysEmitIntoClient for a little longer.
Allow external declaration of global variables via `@_extern(c)`. Such
variables need to have types represented in C (of course), have only
storage (no accessors), and cannot have initializers. At the SIL
level, we use the SIL asmname attribute to get the appropriate C name.
While here, slightly shore up the `@_extern(c)` checking, which should
fix issue #70776 / rdar://153515764.
Don't consider implicitly exposed memory layouts when checking for
usable from inline correctness. That check applies only to memory
layouts marked as exposed explicitly. Consider the implict state only at
the general availability checking.
