Introduce discriminators into freestanding macro expansion expressions
and declarations. Compute these discriminators alongside closure and
local-declaration discriminators, checking them in the AST verifier.
pack expansion type reprs.
Classic variadic parameters still use the postfix ellipsis syntax, and
pack expansion types now use a prefix 'repeat' keyword.
Always parse macro expansions, regardless of language mode, and
eliminate the fallback path for very, very, very old object literals
like `#Color`. Instead, check for the feature flag for macro
declaration and at macro expansion time, since this is a semantic
restriction.
While here, refactor things so the vast majority of the macro-handling
logic still applies even if the Swift Swift parser is disabled. Only
attempts to expand the macro will fail. This allows us to enable the
macro-diagnostics test everywhere.
The "local context" was only used to prevent parsing of closures in a
non-local context, and also string interpolations because they are
similar-ish to closures. However, this isn't something a parser should
decide, so remove this special-case semantic check from the parser and
eliminate the notion of "local context" entirely.
The parser no longer sets local discriminators, and this function is
currently only responsible for adding local type declarations to the
source file. Rename it and remove most of the former callers so it
does just that.
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.
These were keywords prior to Swift 2, and have only been kept around as
keywords to provide a custom error message to rewrite to `#file` et
al. It's incorrect to keep them as keywords, and that error should be
implemented differently if we care about it.
These were replaced by `#file`, `#line`, etc. with SE-0028, prior to
Swift 3. We don't need this custom error message any more, and they
shouldn't be keywords. Stop treating them as keywords in the lexer.
The lexer will be responsible for knowing whether we have a code completion token, everything else will also work for other IDE inspection features.
The changes start to really make sense once I rename CodeCompletion -> IDEInspection in a lot of places.
`getValue` -> `value`
`getValueOr` -> `value_or`
`hasValue` -> `has_value`
`map` -> `transform`
The old API will be deprecated in the rebranch.
To avoid merge conflicts, use the new API already in the main branch.
rdar://102362022
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`.
Fixes rdar://100872195 ( error: 'move' can only be applied to lvalues
error: Can not use feature when experimental move only is disabled!)
Identifiers with a single underscore are not reserved for use by the
language implementation. It is perfectly valid for a library to define
its own '_move'.
The contextual _move keyword should only be parse when it is followed by an lvalue, so should *not* conflict with user-defined '_move' functions.
https://github.com/apple/swift-evolution/blob/main/proposals/0366-move-function.md#source-compatibility
The new Swift parser uses a revamped set of syntax nodes for key paths
that better match the language. However, the C++ parser does not
produce anything like these syntax nodes, so switch to an "old"
keypath node style for now.
Remove the preallocated closure discriminator from KeyPathExpr and go back
to expanding them using an AutoClosureExpr inside of a CaptureListExpr now
that that's supported. This allows the discriminator to be assigned during
type checking without disturbing the indexing of explicit closure literals.
Previously, we would turn a key path literal like `\.foo` in function type
context into a double-wrapped closure like this:
```
foo(\.x) // before type checking
foo({ $kp$ in { $0[$kp$] } }(\.x)) // after type checking
```
in order to preserve the evaluation semantics of the key path literal. This
works but leads to some awkward raw SIL generated out of SILGen which misses
out on various SILGen peepholes and requires a fair number of passes to clean
up. The semantics can still be preserved with a single layer of closure, by
using a capture list:
```
foo({[$kp$ = \.x] in $0[$kp$] }) // after type checking
```
which generates better natural code out of SILGen, and is also (IMO) easier
to understand on human inspection.
Changing the AST representation did lead to a change in code generation that
interfered with the efficacy of CapturePropagation of key path literals; for
key path literals used as nonescaping closures, a mark_dependence of the
nonescaping function value on the key path was left behind, leaving the key
path object alive. The dependence is severed by the specialization done in
the pass, so update the pass to eliminate the dependence.
Compared to the previous patch, this version removes the attempt to have
the type-checked function expression carry the noescape-ness of its context,
and allows for coerceToType to introduce a function conversion instead, since
that FunctionConversionExpr is apparently load-bearing for default argument
generators.
Previously, we would turn a key path literal like `\.foo` in function type
context into a double-wrapped closure like this:
foo(\.x) // before type checking
foo({ $kp$ in { $0[$kp$] } }(\.x)) // after type checking
in order to preserve the evaluation semantics of the key path literal. This
works but leads to some awkward raw SIL generated out of SILGen which misses
out on various SILGen peepholes and requires a fair number of passes to clean
up. The semantics can still be preserved with a single layer of closure, by
using a capture list:
foo({[$kp$ = \.x] in $0[$kp$] }) // after type checking
which generates better natural code out of SILGen, and is also (IMO) easier
to understand on human inspection.
Changing the AST representation did lead to a change in code generation that
interfered with the efficacy of CapturePropagation of key path literals; for
key path literals used as nonescaping closures, a mark_dependence of the
nonescaping function value on the key path was left behind, leaving the key
path object alive. The dependence is severed by the specialization done in
the pass, so update the pass to eliminate the dependence.
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
SequenceExprSyntax should have odd number elements. Previously 'a as b'
was parsed like:
```
(sequence_expr
(identifier_expr "a"),
(as_expr
'as'
(typeidentifier "b")))
```
So it had even number elements. Now it's parsed
```
(sequence_expr
(identifier_expr "a"),
(unresolved_as_expr 'as')
(type_expr
(typeidentifier "b")))
```
