- 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
Currently, this is staged in as `_forget`,
as part of SE-390. It can only be used on
`self` for a move-only type within a consuming
method or accessor. There are other rules, see
Sema for the details.
A `forget self` really just consumes self and
performs memberwise destruction of its data.
Thus, the current expansion of this statement
just reuses what we inject into the end of a
deinit.
Parsing of `forget` is "contextual".
By contextual I mean that we do lookahead to
the next token and see if it's identifier-like.
If so, then we parse it as the `forget` statement.
Otherwise, we parse it as though "forget" is an
identifier as part of some expression.
This way, we won't introduce a source break for
people who wrote code that calls a forget
function.
This should make it seamless to change it from
`_forget` to `forget` in the future.
resolves rdar://105795731
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.
And plumb through the logic such that the
DiagnosticEngine can handle StmtKind. We could
introduce a separate DescriptiveStmtKind a la
DescriptiveDeclKind, but it would be a 1:1 map,
so I'm not convinced it's currently worth doing.
`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
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.
Introduce the compiler directive `#_hasSymbol` which will be used to detect whether weakly linked symbols are present at runtime. It is intended for use in combination with `@_weakLinked import` or `-weak-link-at-target`.
```
if #_hasSymbol(foo(_:)) {
foo(42)
}
```
Parsing only; SILGen is coming in a later commit.
Resolves rdar://99342017
I need to determine when top-level code contains an `await` to determine
whether to make the source file an async context. This logic is
perfectly encapsulated in the `FindInnerAsync` AST walker.
Unfortunately, that is pushed down in Sema/ConstraintSystem and isn't
available at the AST level. I've pulled it up into the brace statement
so that I can use that as part of determining whether the source file is
async in `DeclContext::isAsyncContext`.
Unfortunately, statements don't have an AST context or evaluator or I
would make this a request.
Many, many, many types in the Swift compiler are intended to only be allocated in the ASTContext. We have previously implemented this by writing several `operator new` and `operator delete` implementations into these types. Factor those out into a new base class instead.
At the moment, if there is an error in the `switch` statement expression or if the `{` is missing, we return `nullptr` from `parseStmtSwitch`, but we consume tokens while trying to parse the `switch` statement. This causes the AST to not contain any nodes for the tokens that were consumed while trying to parse the `switch` statement.
While this doesn’t cause any issues during compilation (compiling fails anyway so not having the `switch` statement in the AST is not a problem) this causes issues when trying to complete inside an expression that was consumed while trying to parse the `switch` statement but doesn’t have a representation in the AST. The solver-based completion approach can’t find the expression that contains the completion token (because it’s not part of the AST) and thus return empty results.
To fix this, make sure we are always creating a `SwitchStmt` when consuming tokens for it.
Previously, one could always assume that a `SwitchStmt` had a valid `LBraceLoc` and `RBraceLoc`. This is no longer the case because of the recovery. In order to form the `SwitchStmt`’s `SourceRange`, I needed to add a `EndLoc` property to `SwitchStmt` that keeps track of the last token in the `SwitchStmt`. Theoretically we should be able to compute this location by traversing the right brace, case stmts, subject expression, … in reverse order until we find something that’s not missing. But if the `SubjectExpr` is an `ErrorExpr`, representing a missing expression, it might have a source range that points to one after the last token in the statement (this is due to the way the `ErrorExpr` is being constructed), therefore returning an invalid range. So overall I thought it was easier and safer to add another property.
Fixes rdar://76688441 [SR-14490]
LLVM, as of 77e0e9e17daf0865620abcd41f692ab0642367c4, now builds with
-Wsuggest-override. Let's clean up the swift sources rather than disable
the warning locally.
bindSwitchCasePatternVars() was introduced as a simpler way to wire up
the "parent" links for case variables with same-named case variables
from the previous case item, and is used in the function builders code
to handle switch statements. It duplicated some logic from the
statement checker that did the same thing using a more complicated
algorithm.
Switch (ha ha) the logic in the statement checker over to using
bindSwitchCasePatternVars(), fixing a bug involving unresolved
patterns along the way, and remove the old code that incrementally
wired up the parent links. The resulting code is simpler and is
unified across the various code paths.
Like switch cases, a catch clause may now include a comma-
separated list of patterns. The body will be executed if any
one of those patterns is matched.
This patch replaces `CatchStmt` with `CaseStmt` as the children
of `DoCatchStmt` in the AST. This necessitates a number of changes
throughout the compiler, including:
- Parser & libsyntax support for the new syntax and AST structure
- Typechecking of multi-pattern catches, including those which
contain bindings.
- SILGen support
- Code completion updates
- Profiler updates
- Name lookup changes
This restructures the indentation logic around producing a single IndentContext
for the line being indented. An IndentContext has:
- a ContextLoc, which points to a source location to indent relative to,
- a Kind, indicating whether we should align with that location exactly, or
with the start of the content on its containing line, and
- an IndentLevel with the relative number of levels to indent by.
It also improves the handling of:
- chained and nested parens, braces, square brackets and angle brackets, and
how those interact with the exact alignment of parameters, call arguments,
and tuple, array and dictionary elements.
- Indenting to the correct level after an incomplete expression, statement or
decl.
Resolves:
rdar://problem/59135010
rdar://problem/25519439
rdar://problem/50137394
rdar://problem/48410444
rdar://problem/48643521
rdar://problem/42171947
rdar://problem/40130724
rdar://problem/41405163
rdar://problem/39367027
rdar://problem/36332430
rdar://problem/34464828
rdar://problem/33113738
rdar://problem/32314354
rdar://problem/30106520
rdar://problem/29773848
rdar://problem/27301544
rdar://problem/27776466
rdar://problem/27230819
rdar://problem/25490868
rdar://problem/23482354
rdar://problem/20193017
rdar://problem/47117735
rdar://problem/55950781
rdar://problem/55939440
rdar://problem/53247352
rdar://problem/54326612
rdar://problem/53131527
rdar://problem/48399673
rdar://problem/51361639
rdar://problem/58285950
rdar://problem/58286076
rdar://problem/53828204
rdar://problem/58286182
rdar://problem/58504167
rdar://problem/58286327
rdar://problem/53828026
rdar://problem/57623821
rdar://problem/56965360
rdar://problem/54470937
rdar://problem/55580761
rdar://problem/46928002
rdar://problem/35807378
rdar://problem/39397252
rdar://problem/26692035
rdar://problem/33760223
rdar://problem/48934744
rdar://problem/43315903
rdar://problem/24630624
Accessors logically belong to their storage and can be synthesized
on the fly, so removing them from the members list eliminates one
source of mutability (but doesn't eliminate it; there are also
witnesses for derived conformances, and implicit constructors).
Since a few ASTWalker implementations break in non-trivial ways when
the traversal is changed to visit accessors as children of the storage
rather than peers, I hacked up the ASTWalker to optionally preserve
the old traversal order for now. This is ugly and needs to be cleaned up,
but I want to avoid breaking _too_ much with this commit.
This is a step in the direction of fixing the fallthrough bug. Specifically, in
this commit I give case stmts a set of var decls for the bodies of the case
statement. I have not wired them up to anything except the var decl
list/typechecking.
rdar://47467128
These types are all allocated on the ASTContext's BumpPtrAllocator,
and by default their destructors are never called. (ModuleDecl is the
exception; it registers its destructor with the ASTContext on
construction.)
No functionality change.
Most of this patch is just removing special cases for materializeForSet
or other fairly mechanical replacements. Unfortunately, the rest is
still a fairly big change, and not one that can be easily split apart
because of the quite reasonable reliance on metaprogramming throughout
the compiler. And, of course, there are a bunch of test updates that
have to be sync'ed with the actual change to code-generation.
This is SR-7134.
For now, the accessors have been underscored as `_read` and `_modify`.
I'll prepare an evolution proposal for this feature which should allow
us to remove the underscores or, y'know, rename them to `purple` and
`lettuce`.
`_read` accessors do not make any effort yet to avoid copying the
value being yielded. I'll work on it in follow-up patches.
Opaque accesses to properties and subscripts defined with `_modify`
accessors will use an inefficient `materializeForSet` pattern that
materializes the value to a temporary instead of accessing it in-place.
That will be fixed by migrating to `modify` over `materializeForSet`,
which is next up after the `read` optimizations.
SIL ownership verification doesn't pass yet for the test cases here
because of a general fault in SILGen where borrows can outlive their
borrowed value due to being cleaned up on the general cleanup stack
when the borrowed value is cleaned up on the formal-access stack.
Michael, Andy, and I discussed various ways to fix this, but it seems
clear to me that it's not in any way specific to coroutine accesses.
rdar://35399664
This is our first statement attribute, made more complicated by the
fact that a 'case'/'default' isn't really a normal statement. I've
chosen /not/ to implement a general statement attribute logic like we
have for types and decls at this time, but I did get the compiler
parsing arbitrary attributes before 'case' and 'default'. As a bonus,
we now treat all cases within functions as being switch-like rather
than enum-like, which is better for recovery when not in a switch.
* Implement #warning and #error
* Fix #warning/#error in switch statements
* Fix AST printing for #warning/#error
* Add to test case
* Add extra handling to ParseDeclPoundDiagnostic
* fix dumping
* Consume the right paren even in the failure case
* Diagnose extra tokens on the same line after a diagnostic directive
