When LLDB wraps a user-defined expression in the REPL, it takes something like this
```
<expr>
```
and turns it into (very very abstractly)
```
var result
do {
result = <expr>
}
print(result)
```
In the process, it creates an implicit pattern binding and an implicit do block. Of these, only the implicit do is considered by ASTScope lookup to be relevant. This presents a problem when <expr> is or contains a closure, as the parameters of that closure are defined within a scope that will never be expanded. Thus,
```
> [42].map { x in x } // <- cannot find 'x' in scope
```
This patch provides the Swift half of the fix wherein we privilege pattern bindings created by the debugger and look through them to the underlying user expression when performing ASTScope expansion.
rdar://78256873
The top-level scope for a conditional clause with a pattern is now
ConditionalClausePatternUseScope, which introduces the pattern's
bindings.
Since the patterns are not visible in their own initializer, a new
ConditionalClauseInitializerScope is used for the initializer.
While it is nested inside of the ConditionalClausePatternUseScope,
it's lookup parent skips one level, giving us the desired behavior.
The source range needs to contain any attributes on the subscript
declaration, since those might create child scopes (@_specialize,
property wrappers, etc).
Today, the reported source range of a GuardStmtScope is just that of
the statement itself, ending after the 'else' block. Similarly, a
PatternEntryDeclScope ends immediately after the initializer
expression.
Since these scopes introduce names until the end of the parent
BraceStmt (meaning they change the insertion point), we were
relying on the addition of child scopes to extend the source
range.
While we still need the hack for extending source ranges to deal
with string interpolation, at least in the other cases we can
get rid of it.
Note that this fixes a bug where a GuardStmtScope would end
before an inactive '#if' block if the inactive '#if' block was
the last element of a BraceStmt.
Let's use a ClosureParametersScope for all closures, even those
without an 'in' keyword. This eliminates the need for the
ClosureBodyScope and WholeClosureScope.
Also, let's move the lookup of capture list bindings from
CaptureParametersScope to CaptureListScope. This eliminates the
need for CaptureParametersScope to store a reference to the
capture list, which allows us to remove the AbstractClosureScope
base class entirely.
In a code snippet like the following,
static func ==(a: Foo, b: Foo) -> Bool {
switch (a, b) {
case (.x(let aa), .x(let bb)) where condition(aa, bb),
(.y(let aa), .y(let bb)) where condition(aa, bb):
return aa == bb
default:
return false
}
}
The CaseStmt defines two patterns, both of which bind
'aa' and 'bb'. The first 'aa'/'bb' are in scope inside the
first 'where' clause, and the second 'aa'/'bb' are in scope
inside the second 'where' clause.
Furthermore, the parser creates a "fake" VarDecl for
'aa' and 'bb' to represent the phi node merging the two
values along the two control flow paths; these are in scope
inside the body.
Model this situation by introducing a new CaseLabelItemScope
for the 'where' clauses, and a CaseStmtBodyScope for the
body.
* Re-create `ASTScope` for each completion
* Add generic params and where clause scope even without missing body
* Use `getOriginalBodySourceRange()` for `AbstractFunctionBodyScope`
* Source range translations for replaced ranges when finding scopes
* Bypass source range checks when the completion happens in the replaced
range
* Be lenient with ASTScope / DeclContext mismatch in code completion
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
`@differentiable` attributes may contain `where` clauses referencing generic
parameters from some generic context, just like `@_specialize` attributes.
Without special ASTScope support for `@differentiable` attributes,
ASTScopeLookup.cpp logic tries to resolve the generic parameter `DeclName`s in
`where` clauses based on source location alone
(`ASTScopeImpl::findChildContaining`) and fails.
The fix is to add a special `DifferentiableAttributeScope`, mimicking
`SpecializeAttributeScope`. Every `@differentiable` attribute has its own scope,
derived from the declaration on which it is declared. Unlike `@_specialize`,
`@differentiable` may also be declared on `AbstractStorageDecl` declarations
(subscripts and variables).
Upstreams https://github.com/apple/swift/pull/27451.
Progress towards TF-828: upstream `@differentiable` attribute type-checking.
This commit introduces a request to type-check a
default argument expression and splits
`getDefaultValue` into 2 accessors:
- `getStructuralDefaultExpr` which retrieves the
potentially un-type-checked default argument
expression.
- `getTypeCheckedDefaultExpr` which retrieves a
fully type-checked default argument expression.
In addition, this commit adds `hasDefaultExpr`,
which allows checking for a default expr without
kicking off a request.
Like the last commit, SourceFile is used a lot by Parse and Sema, but
less so by the ClangImporter and (de)Serialization. Split it out to
cut down on recompilation times when something changes.
This commit does /not/ split the implementation of SourceFile out of
Module.cpp, which is where most of it lives. That might also be a
reasonable change, but the reason I was reluctant to is because a
number of SourceFile members correspond to the entry points in
ModuleDecl. Someone else can pick this up later if they decide it's a
good idea.
No functionality change.
Most of AST, Parse, and Sema deal with FileUnits regularly, but SIL
and IRGen certainly don't. Split FileUnit out into its own header to
cut down on recompilation times when something changes.
No functionality change.
