Restrict filtering in `simplifyAppliedOverloadsImpl` to disable
overload set for operators only, because other calls e.g. regular
functions or subscripts could be filtered on labels and are less
overloaded.
Filtering non-operator calls could also lead to incorrect diagnostics
because first choice could have all sorts of different issues e.g.
incorrect labels and number of parameters.
Resolves: rdar://55369704
If member has been bound before the base and the base was
incorrect at that (e.g. fallback to default `Any` type),
then we need to re-activate all of the constraints
associated with this member reference otherwise some of
the constraints could be left unchecked in inactive state.
This is especially important for key path expressions because
`key path` constraint can't be retired until all components
are simplified.
Resolves: SR-13364
Resolves: rdar://66706980
Resolves: rdar://74711236
We now mark some DeclRefExpr and LookupExprs as implicitly async
during typechecking, depending on whether they appear in a context
that is only performing a read / get operation, and whether they
are cross-actor operations.
also resolves rdar://72403401 by improving the error messages
(no more vague "'await' in async context" when its clearly a call!)
The `try await` ordering is both easier to read and indicates the order
of operations better, because the suspension point occurs first and
then one can observe a thrown error.
Currently, we don't have a fix-it to insert 'async', so I've marked those places
as not expecting a fix-it, until someone goes and implements that (rdar://72313654)
Let's consider conditional requirement failure to mean that parent
conformance requirement wasn't satisfied and nothing more, that helps
to disambiguate certain situations and avoid filtering out conditional
failures.
Resolves: rdar://problem/64844584
When an 'async let' initializer can throw, any access to one of the
variables in the 'async let' can also throw, so require such accesses
to be annotated with 'try'.
Customize diagnostics when an 'await' is missing in an 'async let'
initializer. While here, fix the coverage checking so we also diagnose
a missing 'try'.
The initializer of an 'async let' is executed as a separate child task
that will run concurrently with the main body of the function. Model
the semantics of this operation by wrapping the initializer in an
async, escaping autoclosure (representing the evaluation of the child
task), and then a call to that autoclosure (to
This is useful both for actor isolation checking, which needs to treat
the initializer as executing in concurrent code, and also (eventually)
for code generation, which needs to have that code in a closure so
that it can be passed off to the task-creation functions.
There are a number of issues with this implementation producing
extraneous diagnostics due to this closure transformation, which will
be addressed in a follow-up commit.
Extend effects checking to ensure that each reference to a variable
bound by an 'async let' is covered by an "await" expression and occurs
in a suitable context.
We need to preserve the DiagnoseErrorOnTry bit stored in the Context when
exiting a ContextScope. Otherwise, we fail to produce a diagnostic if the
'try' expression pushes an intertwining Context, such as a string interpolation
or 'await'.
Fixes <https://bugs.swift.org/browse/SR-13654>, <rdar://problem/69958774>.
Fix the parsing of await/try/try?/try! so that the two can be nested
(e.g., `await try f()` or `try await f()`).
Then, fix the effects checking logic to preserve all throws-related
information under an `await`, and preserve all async/await-related
information under `try`/`try?`/`try!`.
Add a number of tests, and fix 'await' handling for string
interpolations as well.
Allow async calls and await expressions within @asyncHandler functions.
If we see an async call or await expression in a function that is not
an async context, also suggest adding @asyncHandler if the function
meets the semantic constraints.
Replace the uglified '__await' keyword with a contextual keyword
'await'. This is more of what we would actually want for the
concurrency model.
When concurrency is enabled, this will be a source-breaking change,
because this is valid Swift code today:
```swift
struct MyFuture<T> {
func await() -> }
func doSomething() {
let result = await()
}
}
```
but the call to `await()` will be parsed as an await expression when
concurrency is enabled. The source break is behind the experimental
concurrency flag, but this way we can see how much of an issue it is
in practice.
Closurea can become 'async' in one of two ways:
* They can be explicitly marked 'async' prior to the 'in'
* They can be inferred as 'async' if they include 'await' in the body
Implement missing restrictions on calls to 'async':
* Diagnose async calls/uses of await in illegal contexts (such as
default arguments)
* Diagnose async calls/uses of await in functions/closures that are not
asynchronous themselves
* Handle autoclosure arguments as their own separate contexts (so
'await' has to go on the argument), which differs from error handling
(where the 'try' can go outside) because we want to be more particular
about marking the specific suspension points.
Similar to `try`, await expressions have no specific semantics of their
own except to indicate that the subexpression contains calls to `async`
functions, which are suspension points. In this design, there can be
multiple such calls within the subexpression of a given `await`.
Note that we currently use the keyword `__await` because `await` in
this position introduces grammatical ambiguities. We'll wait until
later to sort out the specific grammar we want and evaluate
source-compatibility tradeoffs. It's possible that this kind of prefix
operator isn't what we want anyway.
* [CSDiagnostics] Adjusting MemberAccessOnOptionalBaseFailure to be able to handle key path component member base types
* [tests] Adding regression tests for SR-5688
* [CSDiagnostics] Adjusting source range to diagnose/insert the fixes in correct location
* [tests] Adjusting regression tests to handle the fixits
* [AST] Creating an helper getSourceRange function for KeyPathExpr::Component
* [ConstraintSystem] Store member base type when recording UnwrapOptionalBase fix
* [AST] Creating a new diagnostic note for removing optional from written type
* [CSDiagnostics] Adjusting logic around MemberAccessOnOptionalBaseFailure to emit the correct diagnostics and fixes
* [tests] Adjusting regression tests to add subscript and key path root cases with respective diagnostics
* [Diagnostics] Adjusting message to mention base type
* [CSDiagnostics] Better naming for method/variable that represents base source range
* [CSDiagnostics] Adjusting to use the stored base member only when member is a key path component.
* [Diagnostics] Adjusting minor typos and code
* [AST] Adjusting keypath root diagnostic note message for use unwrapped type
* [CSDiagnostics] Adjusments in MemberAccessOnOptionalBaseFailure diagnostics as per suggestion
* [tests] Adding more test cases for SR-5688
* [CSDiagnostics] Adjusting fixits for key path root and range for diagnostics
* [CSSimplify] Attempt to diagnose InsertExplicitCall for optional function return types when possible on simplifyOptionalObjectConstraint
* [tests] Adding TODO to improve the diagnostics refering to key path root infered as optional types
* [CSDiagnostics] Adjusting comments
* [CSSimplify] Adjusting logic on simplifyOptionalObjectConstraint to attempt InsertCall fix before remove unwrap
* [CSDiagnostics] Adjust the logic to use resolveType on MemberAccessOnOptionalBaseFailure construction
