This is needed for general fidelity in SIL, since generic argument
lists are used for a lot of different things that aren't restricted
from containing multiple packs. I haven't actually done the work to
use Pack structure to disambiguate the resolution of pack parameters,
but this is a good start.
We'll probably need something like this in source eventually, so
there's no reason to regret adding all the infrastructure for it.
pack expansion type reprs.
Classic variadic parameters still use the postfix ellipsis syntax, and
pack expansion types now use a prefix 'repeat' keyword.
Some testing mechanisms depend on having closure discriminators
pre-computed when dumping the AST. When not dumping to either the
standard error or debugger output streams, trigger computation of
closure discriminators prior to dumping them.
Rather than set closure discriminators in both the parser (for explicit
closures) and then later as part of contextualizing closures (for
autoclosures), do so via a request that sets all of the discriminators
for a given context.
Although the declaration of macros doesn't appear in Swift source code
that uses macros, they still operate as declarations within the
language. Rework `Macro` as `MacroDecl`, a generic value declaration,
which appropriate models its place in the language.
The vast majority of this change is in extending all of the various
switches on declaration kinds to account for macros.
This is the start of the removal of the C++ implementation of libSyntax
in favor of the new Swift Parser and Swift Syntax libraries. Now that
the Swift Parser has switched the SwiftSyntaxParser library over to
being a thin wrapper around the Swift Parser, there is no longer any
reason we need to retain any libSyntax infrastructure in the swift
compiler.
As a first step, delete the infrastructure that builds
lib_InternalSwiftSyntaxParser and convert any scripts that mention
it to instead mention the static mirror libraries. The --swiftsyntax
build-script flag has been retained and will now just execute the
SwiftSyntax and Swift Parser builds with the just-built tools.
In the Swift grammar, the top-level of a source file is a mix of three
different kinds of "items": declarations, statements, and expressions.
However, the existing parser forces all of these into declarations at
parse time, wrapping statements and expressions in TopLevelCodeDecls,
so the primary API for getting the top-level entities in source files
is based on getting declarations.
Start generalizing the representation by storing ASTNode instances at
the top level, rather than declaration pointers, updating many (but
not all!) uses of this API. The walk over declarations is a (cached)
filter to pick out all of the declarations. Existing parsed files are
unaffected (the parser still creates top-level code declarations), but
the new "macro expansion" source file kind skips creating top-level
code declarations so we get the pure parse tree. Additionally, some
generalized clients (like ASTScope lookup) will now look at the list
of items, so they'll be able to walk into statements and expressions
without the intervening TopLevelCodeDecl.
Over time, I'd like to phase out `getTopLevelDecls()` entirely,
relying on the new `getTopLevelItems()` for parsed content. We can
introduce TopLevelCodeDecls more lazily for semantic walks.
Without this change, an `@_objcImplementation` cannot override parent class methods, because the special access control behavior breaks the access control checks for overrides.
Once we have expanded an expression macro, parse and type-check the
result given a priori knowledge of the expanded type. Then, create an
implicit macro-expansion expression to capture the result of the
rewrite.
Introduce `MacroExpansionExpr` and `MacroExpansionDecl` and plumb it through. Parse them in roughly the same way we parse `ObjectLiteralExpr`.
The syntax is gated under `-enable-experimental-feature Macros`.
Introduce the compiler directive `#_hasSymbol` which will be used to detect whether weakly linked symbols are present at runtime. It is intended for use in combination with `@_weakLinked import` or `-weak-link-at-target`.
```
if #_hasSymbol(foo(_:)) {
foo(42)
}
```
Parsing only; SILGen is coming in a later commit.
Resolves rdar://99342017
We needed a way to describe an ABI-safe cast of an address
representing an LValue to implement `@preconcurrency` and
its injection of casts during accesses of members.
This new AST node, `ABISafeConversionExpr` models what is
essentially an `unchecked_addr_cast` in SIL when accessing
the LVAlue.
As of now I simply implemented it and the verification of
the node for the concurrency needs to ensure that it's not
misused by accident. If it finds use outside of that,
feel free to update the verifier.
