And do a first pass of auditing existing uses of the parameter specifiers to
make sure that we look at the ValueOwnership mapping in most cases instead of
individual modifiers.
This lets us consolidate code paths that mostly run in parallel over the
existing InOutTypeRepr/SharedTypeRepr/OwnedTypeRepr family of types. This
patch by itself is NFC but makes it easier to introduce new spellings,
particularly the newly-official `borrowing` and `consuming` modifiers
that were approved in SE-0377.
And use the new bit to ensure we don't try to lower move-only types
with common layout value witness surrogates. Take a bit in the runtime
value witness flags to represent types that are not copyable.
Previously, typechecking and SILGen would treat a function body as fragile as long as the declaration had a `@backDeployed` attribute, regardless of the platform specified by the attribute. This was overly conservative since back deployed functions are only emitted into the client on specific platforms. Now a `@backDeployed` function can reference non-`public` declarations on the platforms it is resilient on:
```
@backDeployed(before: iOS 15)
public func foo() {
#if os(iOS)
// Fragile; this code may be emitted into the client.
#else
// Resilient; this code won't ever be exposed to clients.
#endif
}
```
Resolves rdar://105298520
Various requests expect to be walking over the current source file.
While we could add checks to all these to skip decls outside of the
current buffer, it's a little nicer to handle this during the walk
instead.
Allow ignoring nodes that are from macro expansions and add that flag to
the various walks that expect it.
Also add a new `getOriginalAttrs` that filters out attributes in
generated source.
Global peer macro expansions are not injected into the AST. Instead, they
are visited as "auxiliary declarations" when needed, such as in the decl
checker and during SILGen. This is the same mechanism used for local property
wrappers and local lazy variables.
- Remove the `Rewritten` field and `setRewritten()`. Make `getRewritten()` invoke the request.
- Rename fields `Macro` and `MacroLoc` to `MacroName` and `MacroNameLoc` respectively as well as their getters to match those in `MacroExpansionExpr`.
- Use the name lookup table instead of adding members from a macro expansion to the parent decl context.
- Require declaration macros to specify introduced names and used the declared names to guide macro expansions lazily.
Extend the name mangling scheme for macro expansions to cover attached
macros, and use that scheme for the names of macro expansions buffers.
Finishes rdar://104038303, stabilizing file/buffer names for macro
expansion buffers.
Introduce discriminators into freestanding macro expansion expressions
and declarations. Compute these discriminators alongside closure and
local-declaration discriminators, checking them in the AST verifier.
Having a request for semantic declaration attributes while still allowing
the original linked list to be mutated directly can cause use-after-frees
on pointers to old decl attributes. For now, introduce a request that
expands member attribute macros with a side effect of adding the new
attributes to the list. We can revisit this once attribute mutation via
getAttrs() is audited across the frontend.
Introduce 'getSemanticAttrs', which is a requestified replacement for
'getAttrs'. Right now, AttachedSemanticAttrsRequest calls 'getAttrs',
meaning future additions or removals from the linked list will not be
reflected via 'getSemanticAttrs'. Callers of 'getAttrs' that rely on
mutation will need to turn the computation into a request and vend the
attributes through AttachedSemanticAttrsRequest.
Describe attached macros with the `@attached` attribute, providing the
macro role and affected names as arguments to the macro. The form of
this macro will remain the same as it gains other kinds of attached
macro roles beyond "accessor".
Remove the "accessors" role from `@declaration`, which will be going
away.
Add support for freestanding declaration macros.
- Parse `@declaration` attribute.
- Type check and expand `MacroExpansionDecl`.
Known issues:
- Generic macros are not yet handled.
- Expansion does not work when the parent decl context is `BraceStmt`. Need to parse freestanding declaration macro expansions in `BraceStmt` as `MacroExpansionDecl`, and add expanded decls to name lookup.
Adopt new request-based utilities for looking up the enclosing declaration's availability when type checking an `@available` attribute. This consolidates implementations of the lookup and improves diagnostics by catching more cases where declarations are more available than their containers.
Align the grammar of macro declarations with SE-0382, so that macro
definitions are parsed as an expression. External macro definitions
are referenced via a referenced to the macro `#externalMacro`. Define
that macro in the standard library, and recognize uses of it as the
definition of other macros to use externally-defined macros. For
example, this means that the "stringify" macro used in a lot of
examples is now defined as something like this:
@expression macro stringify<T>(_ value: T) -> (T, String) =
#externalMacro(module: "MyMacros", type: "StringifyMacro")
We still parse the old "A.B" syntax for two reasons. First, it's
helpful to anyone who has existing code using the prior syntax, so they
get a warning + Fix-It to rewrite to the new syntax. Second, we use it
to define builtin macros like `externalMacro` itself, which looks like this:
@expression
public macro externalMacro<T>(module: String, type: String) -> T =
Builtin.ExternalMacro
This uses the same virtual `Builtin` module as other library builtins,
and we can expand it to handle other builtin macro implementations
(such as #line) over time.
Local discriminators for named entities are currently being set by the
parser, so entities not created by the parser (e.g., that come from
synthesized code) don't get local discriminators. Moreover, there is
no checking to ensure that every named local entity gets a local
discriminator, so some entities would incorrectly get a local
discriminator of 0.
Assign local discriminators as part of setting closure discriminators,
in response to a request asking for the local discriminator, so the
parser does not need to track this information, and all local
declarations---including synthesized ones---get local discriminators.
And add checking to make sure that every entity that needs a local
discriminator gets assigned one.
There are a few interesting cases in here:
* There was a potential mangling collision with local property
wrappers because their generated variables weren't getting local
discriminators
* $interpolation variables introduced for string interpolation weren't
getting local discriminators, they were just wrong.
* "Local rename" when dealing with captures like `[x]` was dependent on
the new delcaration of `x` *not* getting a local discriminator. There
are funny cases involving nesting where it would do the wrong thing.
Single expression is not going to cut it in this case because attribute
and attached declaration could have different availability, so we need
to use `if #available` to guard attribute instantiation and return `nil`
in cases where types are not available.
The runtime discoverable attribute generator just like a default
argument or a property wrapper doesn't have a distinct name or
a declaration. Sema should synthesize a call that could be used
to obtain a value of an attribute type and everything else is
going to be synthesized in SILGen.
One of the intended usages of `getRuntimeDiscoverableAttrTypeDecl`
is IRGen where we need to relate unique attributes to a list of their
(decl) attachments.
