`SourceEntityWalker` had an unbalanced `walkToDeclPre` and
`walkToDeclPost`, ie. `walkToDeclPost` could be called even though
`walkToDeclPre` was not. Specifically, this would occur for both
`OperatorDecl` and `PrecedenceGroupDecl` declarations.
These could both be added to the `if` in `walkToDeclPost`, but this
seems fairly errorprone in general - especially as new decls are added.
Indeed, there's already declarations that are being skipped because they
aren't explicitly tested for in `walkToDeclPre`, ie.
`PatternBindingDecl`.
Instead of skipping if not explcitly handled, only skip running the
`SEWalker` walk methods if the declaration is implicit (and not a
constructor decl, see TODO). This should probably also always visit
children, with various decls changed to become implicit (eg.
TopLevelCodeDecl), but we can do that later - breaks too many tests for
now.
This change exposed a few parameter declarations that were missing their
implicit flag, as well as unbalanced walk methods in `RangeResolver`.
We'll need this to get the right 'selfDC' when name lookup
finds a 'self' declaration in a capture list, eg
class C {
func bar() {}
func foo() {
_ = { [self] in bar() }
}
}
Add `async` to the type system. `async` can be written as part of a
function type or function declaration, following the parameter list, e.g.,
func doSomeWork() async { ... }
`async` functions are distinct from non-`async` functions and there
are no conversions amongst them. At present, `async` functions do not
*do* anything, but this commit fully supports them as a distinct kind
of function throughout:
* Parsing of `async`
* AST representation of `async` in declarations and types
* Syntactic type representation of `async`
* (De-/re-)mangling of function types involving 'async'
* Runtime type representation and reconstruction of function types
involving `async`.
* Dynamic casting restrictions for `async` function types
* (De-)serialization of `async` function types
* Disabling overriding, witness matching, and conversions with
differing `async`
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
