This is required because `ApplicableFunction` constraint can
inject member reference constraints that require a declaration
context.
For example, `_ = { Double(...) }` would now produce a disjunction
for `Double.init` where overload choice declaration contexts point
to the closure instead of the enclosing context.
This addresses a long-standing FIXME in `simplifyApplicableFnConstraint`
and helps with disjunction optimizer because its correctness depends on
correct identification of declaration contexts where applications happen.
`participatesInInference` is now always true for
a non-empty body, remove it along with the separate
type-checking logic such that empty bodies are
type-checked together with the context.
Remove this bit from function decls and closures.
Instead, for closures, infer it from the presence
of a single return or single expression AST node
in the body, which ought to be equivalent, and
automatically takes result builders into
consideration. We can also completely drop this
query from AbstractFunctionDecl, replacing it
instead with a bit on ReturnStmt.
Parse typed throw specifiers as `throws(X)` in every place where there
are effects specified, and record the resulting thrown error type in
the AST except the type system. This includes:
* `FunctionTypeRepr`, for the parsed representation of types
* `AbstractFunctionDecl`, for various function-like declarations
* `ClosureExpr`, for closures
* `ArrowExpr`, for parsing of types within expression context
This also introduces some serialization logic for the thrown error
type of function-like declarations, along with an API to extract the
thrown interface type from one of those declarations, although right
now it will either be `Error` or empty.
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.
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.
This saves us from needing to re-match args to params in CSApply and is also
useful for a forthcoming change migrating code completion in argument position
to use the solver-based typeCheckForCodeCompletion api.
rdar://76581093
