This makes more efficient use of the permanent memory allocated for
`AvailabilityContext` representations and also fixes a leak that was introduced
in https://github.com/swiftlang/swift/pull/79718 where the small vector for
unavailable domain storage was not being cleaned up on `ASTContext`
deallocation.
Resolves rdar://145929932.
This is the missing check for "rule #1" in the isolated conformances proposal,
which states that an isolated conformance can only be referenced within
the same isolation domain as the conformance. For example, a
main-actor-isolated conformance can only be used within main-actor code.
Choose names that don't imply availability is versioned, since custom
availability will support domains that are version-less (they are simply
available or unavailable).
Introduce `SemanticAvailableAttr` conveniences to compute the deprecated and
obsoleted ranges for an attribute and ensure they remap versions when needed.
Within the constraint system, introduce a new kind of conformance constraint,
a "nonisolated conforms-to" constraint, which can only be satisfied by
nonisolated conformances. Introduce this constraint instead of the normal
conforms-to constraint whenever the subject type is a type parameter that
has either a `Sendable` or `SendableMetatype` constraint, i.e., when the type
or its values can escape the current isolation domain.
Witness checking itself is allowed to skip `@Sendable` mismatch in this
situation. This is a narrow fix for `SendableCompletionHandlers` feature
to make sure that the behavior doesn't change for non-ObjC witnesses
This simplifies the code to emit availabilty diagnostics and ensures that they
display domain names consistently. While updating existing diagnostics, improve
consistency along other dimensions as well.
Delay resolution of availability domain identifiers parsed in availability
specifications until type-checking. This allows custom domain specifications to
be written in `if #available` queries.
When it's available, use an open-coded allocator function that returns
an alloca without popping if the allocator is nullptr and otherwise
calls swift_coro_alloc. When it's not available, use the malloc
allocator in the synchronous context.
The serialized diagnostic format has some extra fields that we can
adopt for diagnostic groups. Specifically:
* Category: store the diagnostic group name here
* Flags: extend the hack used by educational notes of placing Markdown file paths here
This allows external tools to locate the metadata pointer without needing to call the accessor function.
This is only useful for non-generic types, so we borrow the HasCanonicalMetadataPrespecializations flag to indicate the presence of this pointer on non-generic types, and it continues to indicate the presence of prespecializations for generic types.
Only emit this pointer for internal/private types with no runtime initialization. Public type metadata can be found with the symbol, and it's not useful for types that require runtime initialization.
