With the acceptance of SE-0458, allow the use of unsafe expressions, the
@safe and @unsafe attributes, and the `unsafe` effect on the for..in loop
in all Swift code.
Introduce the `-strict-memory-safety` flag detailed in the proposal to
enable strict memory safety checking. This enables a new class of
feature, an optional feature (that is *not* upcoming or experimental),
and which can be detected via `hasFeature(StrictMemorySafety)`.
Sometimes features are removed from `Features.def`, but they are not
removed from the test files. The compiler ignores every feature that
does not exist. This leads to removed features still being tested, and
with the introduction of #76740, `REQUIRED:`.
Modify the code that generates the active feature set for testing to
also generate the set of existing features, and pass this list of
existing features to the verifier script. If a feature is trying to be
activated and does not exist, the verifier will warn the user.
- `SwiftParser` feature was renamed `ParserASTGen`, but some tests were
using both spellings. Remove the mentions of `SwiftParser` in the
tests.
- `ImportObjcForwardDeclarations` was spelled with upper case `C` in
a couple of tests. Fix it so the matching is easier.
- `TransferringArgsAndResults` was an experimental feature that was
removed.
- Ignore the usage of inexisting feature in `swift-export-as.swift`
because it seems to be what the test is actually testing.
- Ignore the test `availability_define.swift` because it tests the
pseudo-feature `AvailabilityMacro=` which is not part of
`Features.def`.
Take the `Features.def` file used in other parts of the code and create
a file that can be used from the LLVM Lit configuration files to add new
available features that can be checked from the tests with `REQUIRES`
and others.
The file `lit.swift-features.cfg.inc` is preprocessed by Clang and
generates a file with Python syntax that can be loaded from both
`lit.site.cfg.in` files. The preprocessing output is copied into the
different test directories in the build directory, and added it is added
as a dependency of them, so it will be generate when the test run or
when `Features.def` changes.
`EXPERIMENTAL_FEATURES` are only enabled if they are available in
production or the compiler is being built with assertions, while
`UPCOMING_FEATURES` and the rest of the `LANGUAGE_FEATURES` are always
available.
