Replace the existing C++ implementation of extractInlinableText with
a new implementation based on swift-syntax. It uses SwiftIfConfig to
remove inactive regions (with a special mode), and a new compiler-only
entrypoint in the library to remove comments and `#sourceLocation`.
* Strip comments from inlinable text
* Simplify implementation, and avoid trimming trailing whitespace after the comment.
* Update test
* Feedback and handle more cases (with added tests)
* Handle #sourceLocation
* Fix #sourceLocation and fix FileCheck tests
We already have something called "module interfaces" -- it's the
generated interface view that you can see in Xcode, the interface
that's meant for developers using a library. Of course, that's also a
textual format. To reduce confusion, rename the new module stability
feature to "parseable [module] interfaces".
Textual module interfaces don't actually depend on SILGen, so we
shouldn't need to run SILGen (or serialize an entire binary module) if
we're just trying to emit a textual interface. On the other hand, if
we /are/ going to run SILGen and then SIL diagnostics, we shouldn't
delay those diagnostics by spending time emitting a textual interface,
or for that matter a TBD file.
Using this, update all the ModuleInterface tests that use
`-emit-module -o /dev/null` to use `-typecheck` instead, except for
those using `-merge-modules`.
Previously, a #if of the form:
```swift
#if (
false
)
print("x")
#endif
```
Would be emitted after #if-stripping as
```swift
false
)
print("x")
```
Because the old logic assumed conditions will always appear on one line.
Instead, for active clauses that have conditions, skip to the next line
after the end of the condition instead.
* [InterfaceGen] Remove #ifs from default args
This patch removes all #if configs form the bodies of default arguments,
which can contain multiline closures, while preserving the bodies of the
clauses that are active.
This code is generalized and should "just work" for inlinable function
bodies, which will come in a later patch.
* Address review comments
* Fix and test CharSourceRange.overlaps
* Fix CharSourceRange::print to respect half-open ranges
