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.
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.
Pattern matching as currently implemented is consuming, but that's not
necessarily what we want to be the default behavior when borrowing pattern
matching is implemented. When a binding of noncopyable type is pattern-matched,
require it to be annotated with the `consume` operator explicitly. That way,
when we introduce borrowing pattern matching later, we have the option to make
`switch x` do the right thing without subtly changing the behavior of existing
code. rdar://110073984
- replaces "move-only" terminology with "noncopyable"
- replaces compiler jargon like "guaranteed parameters"
and "lvalue" with corresponding language-level notions
- simplifies diagnostics about closures.
and probably more.
rdar://109281444
Before this change it was possible to:
1. Call mutating methods on a consume result.
2. assign into a consume (e.x.: var x = ...; (consume x) = value.
From an implementation perspective, this involved just taking the logic I
already used for the CopyExpr and reusing it for ConsumeExpr with some small
tweaks.
rdar://109479440
Some notes:
1. I implemented this as a contextual keyword that can only apply directly to
lvalues. This ensures that we can still call functions called copy, define
variables named copy, etc. I added tests for both the c++ and swift-syntax based
parsers to validate this. So there shouldn't be any source breaks.
2. I did a little bit of type checker work to ensure that we do not treat
copy_expr's result as an lvalue. Otherwise, one could call mutating functions on
it or assign to it, which we do not want since the result of copy_value is
3. As expected, by creating a specific expr, I was able to have much greater
control of the SILGen codegen and thus eliminate extraneous copies and other
weirdness than if we used a function and had to go through SILGenApply.
rdar://101862423
Make sure we look through a wrapping
`OptionalEvaluationExpr` and its injections when
looking for an assignment to mark a valid if/switch
source expression.
rdar://109305454
Also removes some redundant checks in SILGen for
the flag in order to process `_move` and `_borrow`
that are already checked for in Sema. We will keep
those behind the feature flag for now.
Always use `Decl::visitAuxiliaryDecls` to visit decls produced by macros, including peer macros and declaration macros. Use name-driven expansion for peer macros. Remove `MacroExpansionDecl::getRewritten()`.
Also make `ExpandMacroExpansionDeclRequest` cache the buffer ID (similar to other macros) instead of an array of decls.
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.
It appears that conditional casts require a check of the
type's metadata at runtime. There's no reason for us to
permit that at this time, since all such conditional
casts are going to fail, unless its the identity cast.
That is, a move-only type is currently only a subtype
of itself.
So for now, `is`, `as?`, `as!` casts from or to a
move-only type are now an error. The `as` casts
are permitted only if the two move-only types are
equal.
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.
`OpaqueUnderlyingTypeChecker` should skip conditional availability
blocks if none of the conditions restrict the current target.
Resolves: rdar://103445432
Most of the diagnostics for extra/missing/mislabeled arguments refer
to argument to a "call". Some (but not call) would substitute in
"subscript". None would refer to an argument to a macro expansion
properly.
Rework all of these to refer to the argument in a call, subscript, or
macro expansion as appropriate. Fix up lots of tests that now say
"subscript" instead, and add tests for macro expansions.
An early approach to codegen for `#_hasSymbol` relied on the Darwin platfom SDK, but now that the feature lowers directly to NULL checks in LLVM IR a platform restriction is no longer needed.
However, the tests for `#_hasSymbol` remain unsupported on Windows since that OS does not support weak linking.
`getValue` -> `value`
`getValueOr` -> `value_or`
`hasValue` -> `has_value`
`map` -> `transform`
The old API will be deprecated in the rebranch.
To avoid merge conflicts, use the new API already in the main branch.
rdar://102362022
