It was difficult to preserve the existing, buggy behavior of availability
attribute inference with respect to attributes specifying availability for
non-platform-specific domains. Instead, this change improves attribute merging
by tracking every domain independently, and only merging attributes from the
same domain.
AvailableAttr::Kind and AvailabilityDomain are designed to replace
PlatformAgnosticAvailabilityKind, allowing AvailableAttr to more flexibly model
availability for arbitrary domains. For now, the new constructor just
translates its inputs into inputs for the existing constructor. Once all of the
callers of the existing AvailableAttr constructor have been updated to use the
new constructor, the representation of AvailableAttr will be updated to store
the new properties.
Fixes the immediate problem, but the presence of demangling code in the
runtime means that we'll need a follow-up to fix the compiler so that it
doesn't try to use the demangler to materialize metadata for function types
that have both isolation and a sending result.
rdar://142443925
Introduce an `unsafe` expression akin to `try` and `await` that notes
that there are unsafe constructs in the expression to the right-hand
side. Extend the effects checker to also check for unsafety along with
throwing and async operations. This will result in diagnostics like
the following:
10 | func sum() -> Int {
11 | withUnsafeBufferPointer { buffer in
12 | let value = buffer[0]
| | `- note: reference to unsafe subscript 'subscript(_:)'
| |- warning: expression uses unsafe constructs but is not marked with 'unsafe'
| `- note: reference to parameter 'buffer' involves unsafe type 'UnsafeBufferPointer<Int>'
13 | tryWithP(X())
14 | return fastAdd(buffer.baseAddress, buffer.count)
These will come with a Fix-It that inserts `unsafe` into the proper
place. There's also a warning that appears when `unsafe` doesn't cover
any unsafe code, making it easier to clean up extraneous `unsafe`.
This approach requires that `@unsafe` be present on any declaration
that involves unsafe constructs within its signature. Outside of the
signature, the `unsafe` expression is used to identify unsafe code.
As an example, use this for the "`@preconcurrency` on import has no
effect" warning, which is not yet working correctly. This disables it
by default but leaves it in place for our testing.
We have some problems on Linux where Glibc pulls in `<elf.h>` and then
we end up with conflicting definitions. Fix by using C++ interop and
putting our definitions into a namespace.
rdar://137201928
The newer version of clang will issue warnings in more cases,
specifically, -Winvalid-offsetof and -Wunused-but-set-variable.
This cleans up the new warnings issued from header, which shows up for
every TU that includes them. Fixing them should make the remaining
warnings easier to read.
