If an imported type's conformance cannot be implicitly inferred, allow
it to be explicitly stated via
`__attribute__((__swift_attr__("_BitwiseCopyable")))`.
An imported declaration which has storage that can't be represented in
Swift must not be inferred to be BitwiseCopyable: that inference
involves looking at the (visible) fields.
If an extension isn't imported either directly or via a transitive
(`@_exported`) import, its members should not be visible to name
lookup. Implement this behavior behind the experimental flag
ExtensionImportVisibility.
There are scenarios where different compilers are distributed with
compatible serialization format versions and the same tag. Distinguish
swiftmodules in such a case by assigning them to different distribution
channels. A compiler expecting a specific channel will only read
swiftmodules from the same channel. The channels should be defined by
downstream code as it is by definition vendor specific.
For development, a no-channel compiler loads or defining the env var
SWIFT_IGNORE_SWIFTMODULE_REVISION skips this new check.
rdar://123731777
and implement it for @isolated(any) function types.
The existing testing was pretty broken: we were diagnosing all sorts
of things that don't require type metadata (like using a tuple with
an extended existential in a value position in an API signature)
and not diagnosing several things that do (like covariant function
conversions that erase types). There's therefore some risk to this
patch, but I'm not too worried because needing metadata like this is
pretty uncommon, and it's likely that programs won't build correctly
anyway --- it'll just get caught by the linker instead of the compiler.
When `-enable-lazy-typecheck` is specified, serialization may be expected to
run on an AST containing invalid declarations since type checking may happen
on-demand, during serialization, in this mode. If the declarations that are
invalid are not skipped, then the compiler is likely to crash when attempting
to serialize them. Now, invalid declarations are skipped and an error is
emitted at the end of serialization to note that serialization failed.
Additionally, a new `-Rmodule-serialization` flag can be specified to request
more detailed information about module serialization failures. This would be
useful in a situation where lazy typechecking does not produce any diagnostic
for some reason, but module serialization fails and more information is
therefore required to debug.
Resolves rdar://123260476
When a NoncopyableGenericsMismatch happens between the compiler and
stdlib, allow the compiler to rebuild the stdlib from its interface
instead of exiting with an error.
properties.
Otherwise, types that rely on derived conformances to Equatable and friends will
fail to compile if a library adds a `@preconcurrency @MainActor` annotation. There
is no need to prevent conformance derivation, because the actor isolation checker
still runs on derived witnesses and will diagnose any concurrecy violations (with
appropriate downgrading behavior for `@preconcurrency`).
Instead it is a bit on ParamDecl and SILParameterInfo. I preserve the consuming
behavior by making it so that the type checker changes the ParamSpecifier to
ImplicitlyCopyableConsuming if we have a default param specifier and
transferring is set. NOTE: The user can never write ImplicitlyCopyableConsuming.
NOTE: I had to expand the amount of flags that can be stored in ParamDecl so I
stole bits from TypeRepr and added some logic for packing option bits into
TyRepr and DefaultValue.
rdar://121324715
