Move logic from `ConstraintGenerator::visitOverloadedDeclRefExpr`
to pre-check to avoid including macro declarations referenced
without `#`. This means that pre-checking would synthesize
`TypeExpr` in situations when there is a type reference that
is shadowed by a stdlib macro.
Resolves: https://github.com/apple/swift/issues/67815
Resolves: rdar://114796811
This is phase-1 of switching from llvm::Optional to std::optional in the
next rebranch. llvm::Optional was removed from upstream LLVM, so we need
to migrate off rather soon. On Darwin, std::optional, and llvm::Optional
have the same layout, so we don't need to be as concerned about ABI
beyond the name mangling. `llvm::Optional` is only returned from one
function in
```
getStandardTypeSubst(StringRef TypeName,
bool allowConcurrencyManglings);
```
It's the return value, so it should not impact the mangling of the
function, and the layout is the same as `std::optional`, so it should be
mostly okay. This function doesn't appear to have users, and the ABI was
already broken 2 years ago for concurrency and no one seemed to notice
so this should be "okay".
I'm doing the migration incrementally so that folks working on main can
cherry-pick back to the release/5.9 branch. Once 5.9 is done and locked
away, then we can go through and finish the replacement. Since `None`
and `Optional` show up in contexts where they are not `llvm::None` and
`llvm::Optional`, I'm preparing the work now by going through and
removing the namespace unwrapping and making the `llvm` namespace
explicit. This should make it fairly mechanical to go through and
replace llvm::Optional with std::optional, and llvm::None with
std::nullopt. It's also a change that can be brought onto the
release/5.9 with minimal impact. This should be an NFC change.
When you have a type that's ambiguous because it's defined in 2 imported
modules, but you don't have to disambiguate by using the module name,
previously no index references were produced. Now most are for the
common case, but notably nested type constructors and generics still
aren't emitted, partially because of https://github.com/apple/swift/issues/65726
Fixes: https://github.com/apple/swift/issues/64598
namespace.
This moves the `isInMacroArgument` predicate and `lookupMacros` into `namelookup`.
ASTScope still encapsulates the scope tree and contains the operation to lookup
the enclosing macro scope, which then invokes a callback to determine whether a
potential macro scope is indeed a macro, because answering this question requires
name lookup.
This source location will be used to determine whether to add a name lookup
option to exclude macro expansions when the name lookup request is constructed.
Currently, the source location argument is unused.
- Allow an if/switch expression to become an
implicit return of a function that has a `#if`
body with a single active element that is an `if`
or `switch`.
- Allow `#if` branches of an if/switch expression,
as long as there is a single active expression
element.
rdar://107487977
Provide ASTWalker with a customization point to specify whether to
check macro arguments (which are type checked but never emitted), the
macro expansion (which is the result of applying the macro and is
actually emitted into the source), or both. Provide answers for the
~115 different ASTWalker visitors throughout the code base.
Fixes rdar://104042945, which concerns checking of effects in
macro arguments---which we shouldn't do.
Introduce SingleValueStmtExpr, which allows the
embedding of a statement in an expression context.
This then allows us to parse and type-check `if`
and `switch` statements as expressions, gated
behind the `IfSwitchExpression` experimental
feature for now. In the future,
SingleValueStmtExpr could also be used for e.g
`do` expressions.
For now, only single expression branches are
supported for producing a value from an
`if`/`switch` expression, and each branch is
type-checked independently. A multi-statement
branch may only appear if it ends with a `throw`,
and it may not `break`, `continue`, or `return`.
The placement of `if`/`switch` expressions is also
currently limited by a syntactic use diagnostic.
Currently they're only allowed in bindings,
assignments, throws, and returns. But this could
be lifted in the future if desired.
Factor out some type-checking logic for ReturnStmt,
including the conversion to FailStmt, into a
request. We can then invoke this request from
both the regular type-checking path, as well as
during a pre-check of an expression.
pack expansion type reprs.
Classic variadic parameters still use the postfix ellipsis syntax, and
pack expansion types now use a prefix 'repeat' keyword.
rather than relying on PackElementExprs collected by preCheck.
This handles pack element expressions and pack element type reprs, and enforces that
all packs expanded by a given pack expansion expression all have the same shape.
Once the parser creates PackExpansionExpr directly (based on a dedicated syntax instead
of postfix '...'), the code in preCheck for identifying and creating pack expansions
can simply be deleted.
During prechecking, postfix '...' expressions are rewritten to pack
expansion expressions if the operand contains pack references. References
to packs are replaced with opaque values, and the pack expansion stores
the opaque value bindings to decl refs.
Replace the use of bool and pointer returns for
`walkToXXXPre`/`walkToXXXPost`, and instead use
explicit actions such as `Action::Continue(E)`,
`Action::SkipChildren(E)`, and `Action::Stop()`.
There are also conditional variants, e.g
`Action::SkipChildrenIf`, `Action::VisitChildrenIf`,
and `Action::StopIf`.
There is still more work that can be done here, in
particular:
- SourceEntityWalker still needs to be migrated.
- Some uses of `return false` in pre-visitation
methods can likely now be replaced by
`Action::Stop`.
- We still use bool and pointer returns internally
within the ASTWalker traversal, which could likely
be improved.
But I'm leaving those as future work for now as
this patch is already large enough.
