Introduce some basic support for defining specific language features
that can be checked by name, e.g.,
#if $AsyncAwait
// use the feature
#endif
For backward compatibility with older compilers, to actually prevent
the parser from parsing, one will have to do a Swift compiler version
check, even though the version number doesn't matter. For example:
#if compiler(>=5.3) && $AsyncAwait
// use the feature
#endif
We have two ways of knowing if we're inside of an inactive #if clause.
Refactor the only two places that called getScopeInfo().isInactiveConfigBlock()
to check InInactiveClauseEnvironment instead.
This removes the last remaining usage of Scope that's not related to
parse-time name lookup.
Currently when parsing a SourceFile, the parser
gets handed pointers so that it can write the
interface hash and collected tokens directly into
the file. It can also call `setSyntaxRoot` at
the end of parsing to set the syntax tree.
In preparation for the removal of
`performParseOnly`, this commit formalizes these
values as outputs of `ParseSourceFileRequest`,
ensuring that the file gets parsed when the
interface hash, collected tokens, or syntax tree
is queried.
Remove the `EvaluateConditionals` flags from the
parser, and instead query the source file.
This commit also changes ParserUnit such that it
doesn't evaluate #if conditions by default, as
none of its clients appear to require it. The
only client that wasn't explicitly disabling #if
evaluation and is processing the resulting AST is
swift-indent, so this commit also adds a test to
ensure it continues to work correctly with #if
decls.
Add support for conditional compilation under macCatalyst
Developers can now detect whether they are compiling for macCatalyst at
compile time with:
#if targetEnvironment(macCatalyst)
// Code only compiled under macCatalyst.
#end
For example, for "#if os(simulator)", offer a fixit to change
"os" to "targetEnvironment", instead of offering to change "simulator".
Resolves SR-11037.
Instead of creating the AST directly in the parser (and libSyntax or
SwiftSyntax via SyntaxParsingContext), make Parser to explicitly create
a tree of ParsedSyntaxNodes. Their OpaqueSyntaxNodes can be either
libSyntax or SwiftSyntax. If AST is needed, it can be generated from the
libSyntax tree.
If syntax trees are requested, we shouldn't skip inactive code. Notice the
inactive code won't be skipped in SwiftSyntax because we always set
PerformConditionEvaluation false for the in-process parser.
This is mostly needed for testing purposes where we add -verify-syntax-tree
to regular compiler invocations.
rdar://50837165
Until now, only ">=" was supported in #if swift() expressions, for example:
```#if swift(>=2.1)
```#endif
This means that if we want to evaluate code only when the language version is
less than a particular version we need to do the following:
```#if !swift(>=2.1)
```#endif
An alernative to make this more readable (the "!" can be easily missed in a code
review) is to introduce another supported unary operator, "<". The previous
example could be rewritten like this:
```#if swift(<2.1)
```#endif
This commit adds support for that unary operator, along with some tests.
In Swift3:
* `#if A is B` were warning
* `#if A(foo:)` were warning
* `#if A || B && C` has different meaning from Swift4+ and was diagnosed with
migration support fix-it.
This implementation required a compromise between parser
performance and AST structuring. On the one hand, Parse
must be fast in order to keep things in the IDE zippy, on
the other we must hit the disk to properly resolve 'canImport'
conditions and inject members of the active clause into the AST.
Additionally, a Parse-only pass may not provide platform-specific
information to the compiler invocation and so may mistakenly
activate or de-activate branches in the if-configuration decl.
The compromise is to perform condition evaluation only when
continuing on to semantic analysis. This keeps the parser quick
and avoids the unpacking that parse does for active conditions
while still retaining the ability to see through to an active
condition when we know we're moving on to semantic analysis anyways.
This changes `getBaseName()` on `DeclName` to return a `DeclBaseName`
instead of an `Identifier`. All places that will continue to be
expecting an `Identifier` are changed to call `getBaseIdentifier` which
will later assert that the `DeclName` is actually backed by an
identifier and not a special name.
For transitional purposes, a conversion operator from `DeclBaseName` to
`Identifier` has been added that will be removed again once migration
to DeclBaseName has been completed in other parts of the compiler.
Unify approach to printing declaration names
Printing a declaration's name using `<<` and `getBaseName()` is be
independent of the return type of `getBaseName()` which will change in
the future from `Identifier` to `DeclBaseName`
