They only appear in an intermediate AST and disappear as soon as the
macro is expanded.
The only way to get these in is to construct an "incorrect" AST, e.g.:
```
let x = #does_not_exist() // MacroExpansionExpr
struct S {
#does_not_exist() // MacroExpansionDecl
}
```
This fetches the resource directory directly from the released
toolchains, allowing us to stop prebuilding and assembling them.
Moreover insertion of our resource directory is moved to the lua
tracing configuration (solving a `TODO`) and enhanced. Now all options
that start with the original resource directory (either explicit or
implied) are redirected to our resource directory.
This solves a problem where `-I <original resource dir>/some/path` was
passed to the extractor and did not work.
This works around the 5.9 linux compatibility problem by including the
`PackageDescription` swift modules in the in-dist toolchain. Copying the
toolchain and fixing the `-I` flag was not enough as for some reason
compilation of `PackageDescription.swiftinterface` was causing a crash
in the SIL pass. We work around that by pre-compiling those modules
during the build and including `.swiftmodule` files in the resource
directory.
TODO (apart from testing):
* the libraries included in the macOS toolchain are now fat (they were
intel only before), occupying more space. We should see if we need to
trim them down.
* there might be other swiftinterface files causing problems on linux
lurking around...
* if we go with this, we can simplify and trim down the prebuilding we
do leaving out the resource directory.
* `variables` under `CaseStmt` are now AST children, which solves
orphan `VarDecl`s in that case
* reordered `CaseStmt` AST children to be `labels > variables > body`
(was `body > labels`)
* made `NamedPattern::getVarDecl` an extracted property instead of
`getName`
* The above led to duplicate DB entities because of a quirk in the
Swift compiler code. This is solved by tweaking the extraction of
`variables` under `CaseStmt` to not use `getCaseBodyVariables`.
Before we extracted all the subexpressions from the `SequenceExpr` while we should've only extracted the expressions at odd indices:
```
...
/// SequenceExpr - A list of binary operations which has not yet been
/// folded into a tree. The operands all have even indices, while the
/// subexpressions with odd indices are all (potentially overloaded)
/// references to binary operators.
class SequenceExpr final : public Expr,
...
```
The AST for a `SequenceExpr` looks like this:
```
sequence_expr:
unresolved_dot_expr:
...
assign_expr:
member_ref_expr:
...
dot_syntax_call_expr:
...
unresolved_member_chain_expr:
...
```
however, what's is not visible with the "final" AST is that `unresolved_dot_expr` is the unresolved version of `assign_expr.member_ref_expr` and the `unresolved_member_chain_expr` is the unresolved version of `assign_expr.dot_syntax_call_expr`.
This becomes visible when I enable typechecker debugging:
```c++
auto &typeCheckerOptions = invocation.getTypeCheckerOptions();
typeCheckerOptions.DebugConstraintSolver = true;
```
Which prints the following snippets:
```
---Initial constraints for the given expression---
(assign_expr type='()' location=foo.swift:25:54 range=[foo.swift:25:13 - line:25:57]
(unresolved_dot_expr type='$T2' location=foo.swift:25:29 range=[foo.swift:25:13 - line:25:29] field 'preferredDatePickerStyle' function_ref=unapplied
(unresolved_dot_expr type='$T1' location=foo.swift:25:18 range=[foo.swift:25:13 - line:25:18] field 'datePicker' function_ref=unapplied
(declref_expr type='DatePickerCell' location=foo.swift:25:13 range=[foo.swift:25:13 - line:25:13] decl=foo.(file).DatePickerRowProtocol extension.configurePickerStyle(_:_:).cell@foo.swift:15:33 function_ref=unapplied)))
(unresolved_member_chain_expr implicit type='$T5' location=foo.swift:25:57 range=[foo.swift:25:56 - line:25:57]
(unresolved_member_expr type='$T4' location=foo.swift:25:57 range=[foo.swift:25:56 - line:25:57] name='wheels' function_ref=unapplied)))
// ...
---Type-checked expression---
(assign_expr type='()' location=foo.swift:25:54 range=[foo.swift:25:13 - line:25:57]
(member_ref_expr type='@lvalue UIDatePickerStyle' location=foo.swift:25:29 range=[foo.swift:25:13 - line:25:29] decl=UIKit.(file).UIDatePicker.preferredDatePickerStyle
(force_value_expr implicit type='UIDatePicker' location=foo.swift:25:18 range=[foo.swift:25:13 - line:25:18] implicit_iuo_unwrap
(load_expr implicit type='UIDatePicker?' location=foo.swift:25:18 range=[foo.swift:25:13 - line:25:18]
(member_ref_expr type='@lvalue UIDatePicker?' location=foo.swift:25:18 range=[foo.swift:25:13 - line:25:18] decl=foo.(file).DatePickerCell.datePicker@foo.swift:10:29
(declref_expr type='DatePickerCell' location=foo.swift:25:13 range=[foo.swift:25:13 - line:25:13] decl=foo.(file).DatePickerRowProtocol extension.configurePickerStyle(_:_:).cell@foo.swift:15:33 function_ref=unapplied)))))
(dot_syntax_call_expr type='UIDatePickerStyle' location=foo.swift:25:57 range=[foo.swift:25:56 - line:25:57]
(declref_expr type='(UIDatePickerStyle.Type) -> UIDatePickerStyle' location=foo.swift:25:57 range=[foo.swift:25:57 - line:25:57] decl=UIKit.(file).UIDatePickerStyle.wheels function_ref=unapplied)
(argument_list implicit
(argument
(type_expr implicit type='UIDatePickerStyle.Type' location=foo.swift:25:56 range=[foo.swift:25:56 - line:25:56] typerepr='UIDatePickerStyle')))))
```
The proposed solution is to only extract subexpressions at indices from `SequenceExpr` thus ignoring all the unresolved leftovers.
Note: I'm not entirely sure about the case when there is only child (`elements.size() == 1`) so I'm always extracting it.
This patch fixes the last source of unresolved expressions.
