This is similar to our ban on partial consuming a value for this release. The
reason for this is that, one can achieve a similar affect as partial consumption
via a consumption of the entire value and then a partial reinitialization. Example:
```swift
struct X : ~Copyable { var i = 5, var i2 = Klass() }
var x = X()
_ = consume x
x.i = 5
```
in the case above, we now have a value that is in a partially initialized state.
We still allow for move only types to have their fields initialized as long as
there is an intervening init.
rdar://111498740
As with the initial value of a property that is converted from a stored
property to a computed property by an accessor macro, remove
didSet/willSet. It is the macro's responsibility to incorporate their
code or diagnose them.
Fixes rdar://111101833.
@_implementationOnly was designed for use from resilient modules only,
using it from non-resilient modules in unsupported. This change adds a
warning about it.
If anyone hits this warning, they should either enable library-evolution
or consider adopting the new `internal import` when it is available as
it handles this scenario properly.
What leads to a crash: an @_implementationOnly import fully hides the
dependency from indirect clients. This can lead to the compiler being
unaware of some internal details of a non-resilient module when building
a client against it. In turn this may lead to run time crashes from
miscompilation.
In general one could still use @_implementationOnly in a non-resilient
modules as long as it's referenced only from function bodies. However,
references from even non-public properties does lead to important memory
layout information being hidden from clients of the module.
rdar://78129903
The old C++ pass didn't catch a few cases.
Also:
* The new pass is significantly simpler: it doesn't perform dataflow for _all_ memory locations at once using bitfields, but handles each store separately. (In both implementations there is a complexity limit in place to avoid quadratic complexity)
* The new pass works with OSSA
`CxxRecordSemanticsKind::ExplicitlyUnsafe` and `CxxRecordSemanticsKind::UnsafePointerMember` were never directly used, and those do not indicate semantics: they indicate safety of the type when used from Swift, which should be handled by another request `IsSafeUseOfCxxDecl` instead of `CxxRecordSemantics`.
Having `ExplicitlyUnsafe` and `UnsafePointerMember` as semantics indicators was problematic, for instance, for types that are move-only and store a pointer at the same time. Swift allowed the usage of these types (under the rules for `UnsafePointerMember` types) when move-only types are disabled, and did not apply the move-only attribute on such types when move-only types are enabled.
rdar://110644300
Renamed UnitTest to FunctionTest.
FunctionTests are now instantiated once as global objects--with their
names and the code they are to run--at which time they are stored by
name in a global registry.
Moved the types to the SIL library.
Together, these changes enable defining unit tests in the source file
containing the code to be tested.
Eliminate the error message
error: global freestanding macros not yet supported in script mode
by implementing name lookup, type checking, and code emission for
freestanding macros. The key problem here is that, in script mode,
it is ambiguous whether a use of a freestanding macro is an expression
or a declaration. We parse as an expression (as we do within a
function body), which then gets wrapped in a top-level code
declaration.
Teach various parts of the compiler to look through a top-level code
declaration wrapping a macro expansion expression that is for a
declaration or code-item macro, e.g., by recording these for global
name lookup and treating their expansions as "auxiliary" declarations.
Fixes rdar://109699501.
Address a few related issues that affect local types and opaque result types within macros:
* Don't add local types or opaque types encountered while parsing the
arguments of a freestanding macro to the global list. When we do add
them, make sure we're adding them to the outermost source file so
they'll get seen later. This avoids trying to generate code for these
types, because they aren't supposed to be part of the program. Note
that a similar problem remains for arguments to attached macros, which
will need to be addressed with a more significant refactoring.
* When determining whether opaque types should be substituted within a
resilience domain, check the outermost source files rather than the exact
source file, otherwise we will end up with a mismatch in
argument-passing conventions.
* When delaying the type checking of functions that occur as part of a
macro expansion, make sure we record them in the outermost Swift source
file. Otherwise, we won't come back to them.
There is a common theme here of using AST state on the source file in
a manner that isn't ideal, and starts to break down with macros. In
these cases, we're relying on side effects from earlier phases
(parsing and type checking) to inform later phases, rather than
properly expressing the dependencies through requests.
Fixes rdar://110674997&110713264.
APIs on ForwardingInstruction should be written as static taking in
a SILInstruction as a parameter making it awkward.
Introduce a ForwardingOperation wrapper type and move the apis from the
old "mixin" class to the wrapper type.
Add new api getForwardedOperands()
stated in the original source.
If an extension macro can introduce protocol conformances, macro expansion
will check which of those protocols already have a stated conformance in the
original source. The protocols that don't will be passed as arguments to
extension macro expansion, indicating to the macro that it should only add
conformances to those protocols.
